Advances in the Treatment of Neurodegenerative Disorders Employing Nanoparticles

Recent Patents on Drug Delivery & Formulation 2012, 6, 000-000 1

1872-2113/12 $100.00+.00 © 2012 Bentham Science Publishers

Advances in the Treatment of Neurodegenerative Disorders Employing Nanoparticles

Carlos Spuch1*, Ortolano Saida

1 and Carmen Navarro

1

1Department of Pathology and Neuropathology, University Hospital of Vigo, Spain

Received: November 3, 2011; Accepted: December 6, 2011; Revised: November 30, 2011

Abstract: Nanoparticles could potentially revolutionise treatment for neurodegenerative diseases such as Alz-heimer's disease (AD), Parkinson's disease (PD) and strokes. Nanotechnologies hold great promise in brain therapy

as they protect the therapeutic agent and allow its sustained release; the nanoparticles can be used as gene delivery ve-

hicles. The application of neurotrophic factors is able to modulate neuronal survival and synaptic connectivity and it is a

promising therapeutic approach for many neurodegenerative diseases, however, due to limitations posed by the restrictive

blood brain barrier (BBB), it is very difficult to ensure long-term administration in the brain. Drug delivery to the brain

remains the major challenge for the treatment of all neurodegenerative diseases because of the numerous protective barri-

ers surrounding the central nervous system (CNS). New therapeutics with the capacity to cross the BBB is critically

needed for treatment of these diseases. In recent years, nanotechnology had patented new formulations and has evolved as

a new treatment for brain diseases, especially for neurodegenerative diseases, where genetically engineered cells can be

used to deliver specific growth factors to target cells.

Overall, the aim of this review is to summarize the last patents, clinical trials and news related with nanoparticles technol-

ogy for the treatment of neurodegenerative diseases.

Keywords: Alzheimer’s disease, blood brain barrier, brain, central nervous system, drug delivery, nanotechnology, nanoparti-cles, neurodegenerative diseases, Parkinson’s disease, prion diseases, therapeutics.

NEURODEGENERATIVE DISEASES

Neurodegenerative diseases are some of the most debili-tating disorders, affecting thinking, skilled movements, feel-ings, cognitive and memory. Nowadays neurodegenerative diseases are the fourth leading cause of death in the devel-oped world after heart diseases, cancer and stroke [1]. Each year, over 10 million people globally suffer from neurode-generative diseases. This figure is expected to grow by 20% over the next decade as the aging population increases and lives longer. Many similarities appear that relate these dis-eases to each other on a sub-cellular and molecular levels [2]. Discovering these similarities and signalling pathways could offer hope for therapeutic advances that ameliorate many diseases simultaneously.

The spectrum of disorders of the brain is large, covering hundreds of disorders that are listed in either the mental or neurological disorder chapters of the established interna-tional diagnostic classification systems. These disorders have a high prevalence as well as short- and long-term impair-ments and disabilities. Therefore they are an emotional, fi-nancial and social burden to the patients, their families and their social network. Only within the group of neurodegen-erative disease includes serious disorders such as AD, PD, Lewy body dementia (LBD), frontotemporal dementia

*Address correspondence to this author at the Department of Pathology and Neuropathology, University Hospital of Vigo, Hospital of Meixoeiro,

Meixoeiro s/n, 36215, Vigo, Spain; Tel: +34 986814585; Fax: +34 986276416; E-mail1: [email protected];

2: [email protected]

(FTD), Vascular dementia (VD) and some rare disorders such as amyotrophic lateral sclerosis (ALS), Huntington dis-ease (HD), spinocerebellar ataxia and prion diseases [3]. Despite the important differences in clinical manifesta-tion, neurodegenerative disorders share common features such as their appearance late in life, the extensive neuronal loss and synaptic abnormalities, and the presence of cerebral deposits of misfolded proteins aggregates [3]. Approxi-mately 24 million people worldwide suffer from dementia, 60% of cases being due to AD, which occurs in 1% of indi-viduals aged 50 to 70 and dramatically increases to 50% for those over 70 years [4]. Dramatically, these numbers are estimated to increase to 15 million in the next 40 years [5].

AD is a chronic and progressive neurodegenerative dis-order and the most cause of dementia in the elderly. It is typified clinically by learning and memory impairment and pathologically by gross cerebral atrophy, indicative of neu-ronal loss, with numerous extracellular neuritic amyloid plaques and intracellular neurofibrillary tangles found pre-dominantly in the frontal and temporal lobes, including the hippocampus [6]. Although the mechanisms underlying AD are not completely clear yet several approaches aimed at inhibiting disease progression have advanced to clinical tri-als. Among these, strategies targeting the production and clearance of the amyloid-beta peptide are the most advanced [7]. In AD there are two types of protein deposits: amyloid plaques are deposited extracellularly in the brain parenchyma and around the cerebral vessels walls and their main compo-nent is a 1-40 and 1-42 residues peptide termed beta-amyloid protein [8, 9].

https://www.researchgate.net/publication/7409168_Global_Prevalence_of_Dementia_A_Delphi_Consensus_Study?el=1_x_8&enrichId=rgreq-c06c8b6a-9d0a-49e8-9df4-2a3b866cbf2d&enrichSource=Y292ZXJQYWdlOzIyMTc3MzMwMztBUzoxMzc5ODYxMzgxODU3MzBAMTQwOTkwOTg2NzgzMw==

https://www.researchgate.net/publication/49826428_Alzheimer_Disease_Advances_in_Pathogenesis_Diagnosis_and_Therapy?el=1_x_8&enrichId=rgreq-c06c8b6a-9d0a-49e8-9df4-2a3b866cbf2d&enrichSource=Y292ZXJQYWdlOzIyMTc3MzMwMztBUzoxMzc5ODYxMzgxODU3MzBAMTQwOTkwOTg2NzgzMw==

2 Recent Patents on Drug Delivery & Formulation, 2012, Vol. 6, No. 1 Spuch et al.

It is well established that innocuous monomers of amy-loid beta become neurotoxic upon aggregation [10] and the toxicity of amyloid beta involved self aggregation of mono-mers into oligomers and higher aggregated forms [11]. Amy-loid plaques in the human AD brain are known to contain a heterogeneous mixture of amyloid beta peptides [12]. In ad-dition to main amyloid beta species (1-40 and 1-42), a vari-ety of post-transcriptionally modified variants have been identified [13]. The predominant accumulation and initial peptide deposited in the brain parenchyma is a highly fibril-logenic amyloid-beta 1-42 [9]. Targeting amyloid-beta 1-42 in all its aggregation forms has been suggested for therapeu-tic and diagnostic purposes [14, 15]. Moreover, it has been recently demonstrated that brain and blood amyloid-beta are in equilibrium through the BBB, and sequestration of amy-loid-beta in the blood may shift this equilibrium, drawing out the excess from the brain [16-18].

PD is also a chronic and progressive movement disorder that involves the malfunction of dopaminergic neurons. It is not fatal but it gets worse over time. The symptoms of the disease include tremors, stiffness and slow or hesitant speech. PD is characterized by massive depletion of striatal dopamine as a result of degeneration of dopaminergic neu-rons in the substantia nigra pars compacta. Besides the lack of dopamine at the cellular level may appear the formation of Lewy bodies in the substantia nigra, which are cytoplasmic inclusions composed of fibrils, ubiquitin and alpha-synuclein [19, 20]. Worldwide, there are an estimated 7-10 million people living with PD. Unfortunately, many people with PD will develop a mild form of dementia, with slowed though processes, memory problems, difficulty concentrating, apa-thy and poor motivation, word-finding difficulty with com-plicated tasks or tasks involving visual space. Actually there are almost 1.2 million people suffering from PD in Europe and over 1 million in US, however, medication only provides patients with temporary symptomatic relief, while access to care and treatment differs widely depending on where pa-tients live [21].

LBD is the second most common type of progressive dementia after AD, causes a progressive decline in mental abilities. LBD is characterized by fluctuations in cognition with variations in attention and alertness, recurrent formed visual hallucinations, visual spatial dysfunction and, like PD; LBD can result in rigid muscles, slowed movement and tremors [22]. Despite the heterogeneity of their clinical phe-notypes, a significant neuropathological overlap is observed among AD, PD and LBD. The hallmark histological lesion is the presence of Lewy bodies and Lewy neurites. Variation in the distribution of Lewy body pathology is present among LBD, with more neocortical and limbic system Lewy bodies in both [23].

LBD overlaps clinically with AD and PD, but is more associated with the latter. With LBD, the loss of cholinergic neurons is thought to account for the degradation of cogni-tive functioning, as in AD; while the loss of dopaminergic neurons is thought to account for the degradation of motor control, as in PD. Thus, LBD is similar in some ways to both the dementia resulting from AD and PD. The overlap of neu-ropathologies and presenting symptoms (cognitive, emo-tional, and motor) can make an accurate differential diagno-

sis difficult. In fact, it is often confused in its early stages with AD or VD, the main difference is that AD usually be-gins quite gradually and LBD often has a rapid and acute onset, with especially rapid decline in the first few months. Current estimates are that about 60 to 75% of diagnosed de-mentias are of the AD and 10 to 15% are LBD [24].

FTD is a clinical syndrome associated with shrinking of the frontal and temporal anterior lobes of the brain. The cur-rent designation of the syndrome groups together Pick’s dis-ease, primary progressive aphasia, and semantic dementia as FTD. As it is defined today, the symptoms of FTD fall into two clinical patterns that involve either: changes in behav-iour and problems with language. The first symptoms often involve changes in personality, judgment, planning and so-cial functioning. Individuals may make rude or off-colour remarks to family or strangers. They may show apathy and loss of interest or excessive happiness and excitement. Indi-viduals may have a strong desire to eat and gain weight as a result [25].

FTD affects parts of the brain containing microscopic Pick bodies; abnormal protein-filled structures that develop within neurons. The histological features of FTD are the presence of neurofibrillary tangles of phosphor-Tau in the brain [26]. Also, a variety of mutations on several different genes have been linked to specific subtypes of FTD such as MAPT, PGRN, FUS or VCP genes [27]. But more than half the people who develop FTD have no family history of de-mentia. FTD is often misdiagnosed as a psychiatric problem or as AD, but FTD tends to occur at a younger age than does AD, typically between the ages 40 and 70 [28].

VD is widely considered the second most common type of dementia. It is a distinct type of dementia with spectrum of specific clinical and pathophysiological features. How-ever, in a very large majority of cases, these alterations occur in an already aged brain, characterized by a milieu of cellular and molecular events common for different neurodegenera-tive diseases. VD develops when impaired blood flow to parts of the brain deprives cells of food and oxygen. The diagnosis may be clearest when symptoms appear soon after a single major stroke blocks a large blood vessel and disrupts the blood supply to a significant portion of the brain. This situation is sometimes called post-stroke dementia. Symp-toms of VD can vary, depending on the specific brain areas deprived of blood. Impairment may occur in steps, where there is a fairly sudden, noticeable change in function, rather than the slow, steady decline usually seen in AD. Memory problems may or may not be a prominent symptom, depend-ing on whether brain regions important in memory are af-fected [29].

Other rare neurodegenerative diseases with a much lower incidence but equally serious are:

• ALS is a form of motor neuron disease caused by the degeneration of neurons located in the ventral horn of the spinal cord and the cortical neurons that provide their afferent input. This disorder is characterized by rapidly progressive weakness, muscle atrophy and fas-ciculation, spasticity and respiratory compromise [30].

• HD is a rare fatal brain disorder caused by inherited changes in a single gene called huntingtin (Htt). The

Nanoparticles for the Treatment of Neurodegenerative Disorders Recent Patents on Drug Delivery & Formulation, 2012, Vol. 6, No. 1 3

disease is caused by an autosomal dominant mutation on either of an individual's two copies of the gene. It is the most common genetic cause of abnormal involuntary writhing movements called chorea. These changes lead to destruction of neurons in certain brain regions [31].

• Spinocerebellar ataxia is an inherited disorder of brain function. It is characterized by increasing problems with coordination that often affect the legs, hands and speech. There are more than 20 types of spinocerebellar ataxia that have been described [32]. All types of spinocerebel-lar ataxia are characterized by a progressive incoordina-tion of walking. In addition, they are often associated with poor coordination of hand movements, eye move-ments, and speech.

• With some exceptions, the onset of symptoms usually occurs after the age of 18. Spinocerebellar ataxia is slowly progressive, which means that symptoms of the condition gradually worsen over a period of years. Some types of spinocerebellar ataxia can progress more rap-idly than others. Brain scans such as magnetic resonance imaging (MRI) and computerized tomography (CT) of affected persons often show shrinkage or atrophy of the cerebellum that becomes more noticeable as the disease progresses [33].

• Prion diseases are conformational neurodegenerative disorders characterized by the structural modification of the normal cellular prion protein (PrPC) into a patho-logical conformer, scrapie prion protein (PrPSc) [34]. They are a unique category of illness in that they can be inherited, infectious or sporadic in occurrence. Thus, the conversion of PrPC to PrPSc can be related to an exoge-nous infectious source of PrPSc, a mutation in the prion protein that predisposes to such a conformational change or a spontaneous conformational change, as occurs in sporadic prion disease. A comprehensive body of evi-dence has presented compelling data that the transmissi-

ble pathogen for these diseases is a proteinaceous infec-tious particle (hence the term ‘prion’).

• These spontaneous disorders in humans are very rare, affecting only about one person per million worldwide each year. However, transmissible prion proteins can reach epidemic proportions, as was seen in the UK. Cur-rently, there is no effective therapy for this group of dis-eases [35].

NANOPARTICLES TECHNOLOGY AS THERAPEU-TIC CHALLENGES FOR NEURODEGENERATIVE DISEASES

Recent years have witnessed unprecedented growth of research and applications in the area of nanotechnology. There is increasing optimism that nanotechnology, as applied to biomedicine, will bring significant advances in the diag-nosis and treatment of disease. Anticipated applications in medicine include drug delivery, diagnostics and production of improved biocompatible materials [18, 36-38] Table 1. The advent of nanotechnology can provide a solution to overcome the future diagnostic and new neurotherapeutic challenges for neurodegenerative diseases as frequent as AD, PD, FTD, HD, etc.

Nanoparticles are solid colloidal matrix-like particles made of polymers or lipids, generally administered by intra-venous route like liposomes. This technology employs engi-neered materials with the smallest functional organization on the nanometre scale that are able to interact with biological systems at the molecular level. Nanotechnology employs engineered materials or devices with the smallest functional organization on the nanometre scale (1–100nm) that are able to interact with biological systems at the molecular level. Engineered nanoparticles are an important tool to realize a number of these applications. It has to be recognized that not all particles used for medical purposes comply with the re-cently proposed and now generally accepted definition of a

Table 1. Overview of Nanoparticles and their Applications

Particle Class Materials Application

Chitosan Drug and gene delivery

Dextrane Drug and gene delivery

Gelatine Drug and gene delivery

Alginates Drug and gene delivery

Liposomes Drug and gene delivery

Natural materials

Starch Drug and gene delivery

Dendrimers Branched polymers Drug delivery

Fullerenes Carbon based carriers Photodynamics and drug delivery

SPIONS Imaging by MRI Ferrofluids

USPIONS Imaging by MRI

Quantum dlots Cd/Zn selenides Imaging and diagnostic


size 100nm. However, this does not necessarily has an im-pact on their functionality in medical applications. The rea-son why these nanoparticles are attractive for medical pur-poses is based on their important and unique features, such as their surface to mass ratio that is much larger than that of other particles, their quantum properties and their ability to adsorb and carry other compounds. Nanoparticles have a relatively large (functional) surface which is able to bind, adsorb and carry other compounds such as drugs, probes and proteins. However, many challenges must be overcome if the application of nanotechnology is to realize the anticipated improved understanding of the pathophysiological basis of disease, bring more sophisticated diagnostic opportunities, and yield improved therapies.

The advantages of using nanoparticles as a drug delivery system include:

• Particle size and surface characteristics of nanoparticles can be easily manipulated to achieve both passive and active drug targeting after parenteral administration.

• They control and sustain the release of drugs during their transportation and at the site of localization, alter-ing organ distribution and subsequent clearance of the drug so as to achieve increase in drug therapeutic effi-cacy and to reduce its side effects.

• Controlled release and particle degradation characteris-tics can be readily modulated by the choice of matrix constituents. Drug loading is relatively high and drugs can be incorporated into the systems without any chemi-cal reaction. For preserving the drug activity, this is an important factor.

• Site-specific targeting can be achieved by attaching tar-geting ligands to surface of particles or by the use of magnetic guidance.

• The system can be used for various routes of administra-tion including oral, nasal, parenteral, intra-ocular etc.

Nanoparticles can be prepared from a variety of materials such as proteins, polysaccharides and synthetic polymers. The factors that govern the selection of materials for the preparation of nanoparticles include the size of nanoparticles required, inherent properties of the drug e.g., aqueous solu-bility and stability; surface characteristics such as charge and permeability, degree of biodegradability, biocompatibility and toxicity, desired drug release profile and antigenicity of the final product.

Initially, the intravenous administration of nanoparticles did not prove to be successful in targeting the drugs to the brain. Limitations of drug targeting by nanoparticles was described to reach the central nervous system in appreciable quantity was attributed to their uptake by the reticulo-endothelial system. This mechanism significantly removes a large portion of nanoparticles from the vascular space, thus limiting their exposure to the cerebrovasculature and result-ing in decreased drug concentration in the brain. The prob-lem of rapid uptake of nanoparticles by the reticulo-endothelial system was partially solved by coating them with surfactants [39]. Primary surfactants used include polaxam-ine 908 and polysorbate-80.

The treatment of brain disorders is particularly challeng-ing because of a variety of formidable barriers to effective and persistent delivery of therapeutic compounds. From sev-eral perspectives the brain is a challenging organ for drug delivery. First, the incidence of degenerative diseases in the brain will increase with the aging population. Secondly, the BBB is well-known as the best gatekeeper in the body to-ward exogenous substances [40]. Generally pharmaceuticals including most small molecules do not cross the BBB. The endothelial barrier is specifically tight at the interface with the brain astrocytes and can in normal conditions only be passed using endogenous BBB transporters resulting in car-rier mediated transport, active efflux transport and receptor mediated transport [41]. However the barrier properties may be compromised intentionally or unintentionally by drug treatment allowing passage of nanoparticles. Nanoparticles are able to penetrate the BBB of in vitro and In vivo models disrupting the temporally the barrier and allowing the incor-poration the therapeutic agents into the brain [42]. One inter-esting pathway to reach introduce drugs with nanoparticles into the brain can be with previous phagocytise using im-mune cells that are able to across the BBB [43-45] Fig. (1).

Nanoparticles are able to penetrate the BBB of in vitro and In vivo models; and therefore can be used to develop diagnostic tools as well as nano-enabled delivery systems that can bypass the BBB in order to facilitate conventional and novel neurotherapeutic interventions such as drug ther-apy, gene therapy, and tissue regeneration. The ideal nanoparticles properties required for the drug brain delivery are:

1. Nontoxic, biodegradable and biocompatible: There is a large variety of the nanoparticles developed so far, how-ever we will focus on nanoparticles investigated from brain delivery. Nanoparticles made of polybutycya-noacryllate (PBCA) have been intensively investigated since 20 years ago showing that when coated with the non-ionic surfactant polysorbate 80 they permitted to deliver drugs to the brain with many limitations in the pharmacokinetic profile and low stability in blood circu-lation [46]. Today the best alternative nontoxic, biode-gradable and biocompatible for the nanoparticles are made of polylactide homopolimers (PLA) and poly(lactide-co-glycolide) heteropolymers (PLGA) [47].

2. Particle with diameter below 100nm: Nanoparticles size can influence the biodistribution and bioavailability. The nanoparticles range between 10-1000nm, however, nanoparticles with size above 100 nm the clearance rate by the mononuclear phagocyte system increases with the size, while for sizes below 100nm charge is more impor-tant [48]

3. Physical stability in blood to avoid the aggregation: The toxicity of several types of nanoparticles was attributed to a disseminated intravascular coagulation and associ-ated events related to the physical surface properties rather than to the chemical toxicity [49].

4. Prolonger blood circulation time avoiding the mononu-clear phagocyte system: Lacking stealth properties, nanoparticles administered intravenously are rapidly cleared from the blood stream by the mononuclear


phagocyte system and mainly accumulated in liver and spleen [50]. Only pegylated nanoparticles have lower mononuclear phagocyte system uptake and prolonged blood circulation in vivo.

5. BBB targeted and brain delivery: Most of the nanoparti-cles cannot freely diffuse through the BBB and require receptor-mediated transport through brain capillary en-dothelium and epithelium from choroid plexus. To im-prove this property has been carried out nanoparticles with pegylated immunoliposomes that access the brain form blood via receptor mediated transcytosis and de-liver their content into the brain parenchyma without damaging the BBB. This requires the presence of recep-tor specific targeting ligands at the tip of the PEG strands, such as monoclonal antibodies able to trigger the activation of receptors (transferring or insulin recep-tors) [51-53].

6. Scalable and cost-effective manufacturing process: The potential use of nanotechnology in medicine for clinical applications always needs an evaluation of cost effective during the manufacturing process.

7. Amenable to small molecules, peptides, proteins and nucleic acids: Due to the hydro solubility of these mole-cules the preparation method is generally based on the water-in-oil-water solvent evaporation technique [54].

However, proteins are highly organized complex struc-tures that have to be preserved to maintain biological ac-tivity. To avoid structural and chemical integrity lost during nanoparticle preparation and storage, each nanoparticle formulation of protein is unique and re-quires specific adaptation and evaluation [55].

8. Possible modulation of drug release profiles: Nanotech-nology may represent a breakthrough to overcome prob-lems associated with cell therapy. Advances in material biocompatibility and production protocols have put this field close to its clinical application. However, issues such as the possibility of tracking drug-containing nanoparticles, monitoring drug viability, and discon-tinuation of the therapeutic activity when necessary [56].

Actually, peptides are considered the new generation of biologically active tools because they are key regulators in cellular and intercellular physiological responses, which pos-sess enormous potential for the treatment of various central nervous system diseases [57]. In spite of their clinical poten-tial, native peptides have seen limited use due to their poor bioavailability and low stability in physiological conditions. Some strategies used to improve both bioavailability and uptake of peptide drugs for delivery into the brain was sug-gested by conjugation to a polymer such as nanoparticles can offer tremendous hope in the treatment of brain disorders. At

Fig. (1). Schematic representation of different actions of nanoparticles within neuron (axon, dendrites or cytoplasm).


the same manner that we commented previously with other drugs, the polymer conjugation with peptides improves pharmacokinetics by increasing the molecular mass of pro-teins and peptides and shielding them from proteolytic en-zymes. These new strategies will create new opportunities for the future development of neuro-therapeutic drugs. Re-cently, Chen et al. developed 29-amino-acid peptide derived from rabies virus glycoprotein (RVG29) peptide conjugated itraconazole-loaded albumin nanoparticles (RVG29-ITZ-NPs). The RVG29 peptide was conjugated to the albumin nanoparticles using biotin-binding streptavidin as cross linker. They demonstrated that RVG29 significantly facili-tated the intracellular delivery of nanoparticles and a signifi-cant accumulation was observed for RVG29 nanoparticles in brain. They suggested that these nanoparticles can be ex-ploited as a potential therapeutic formulation for the intrac-ranial fungal infection [58].

Also, alternatives routes to drug delivery to the brain are being developed in the laboratories. In the meantime intrave-nous administration is most popular choice in clinical stud-ies. However, some approaches that have been gaining con-siderable attention, such as oral route, inhalation or intra-traqueal installation, via migration along the olfactory or trigeminal nerve ending after deposition on the olfactory mucosa in the nasal region, convection enhanced diffusion

and intratechal drug delivery systems in addition to conven-tional model like intravenous administration. Therefore, the administration route of nanoparticles becomes an important criterion of consideration so as to overcome the physiologi-cal barriers of the brain and to achieve high drug concentra-tions therein [59-62] Table 2.

UP-TAKE MECHANISMS OF NANOPARTICLES INTO BRAIN

Overcoming the difficulty of delivering therapeutic agents to specific regions of the brain presents a major chal-lenge to treatment of most brain disorders. In its neuropro-tective role, the BBB functions to hinder the delivery of many potentially important diagnostic and therapeutic agents to the brain.

Transport from the blood to the brain is limited by the BBB. The barrier is formed by brain endothelial cells that line the cerebral microvessels. It is supported by other cell types surrounding the endothelium, such as astrocytes and pericytes [41]. These surrounding cells contribute to the in-duction of many barrier characteristics of the endothelium, such as tight junctions, that closely join the endothelial cells together. However, the BBB is also a transport barrier. This aspect is formed by specific transport proteins and transcyto-

Table 2. The administration route of nanoparticles becomes an important criterion of consideration so as to overcome the physio-

logical barriers of the brain and to achieve high drug concentrations therein. Table 2 summarize a list of recent patents

employing nanoparticles to treat specifically the brain

Class Function Into Brain Patent Number Reference

Nanocapsules Drug delivery TW201006495

WO2009135853

[63]

[64]

Gold nanoparticle Drug delivery US2011262546 [151]

Magnetic nanoparticle Drug delivery and imaging US2011213193 [65]

Solid lipid nanoparticle Drug delivery US2011208161 [66]

Nanoparticle Drug delivery US2011195125 [67]

Gold nanoparticle Drug delivery US2011111040 [68]

HDL nanoparticle Imaging WO2011044545 [69]

Nanoparticle Drug delivery MX2010012137 [70]

Nanoemulsion Drug delivery CN101884614 [71]

Hydrophilic nanoparticle Drug delivery CN101701061 [72]

Dendritic conjugates Diagnostic WO2009142754 [73]

Gold nanoparticle Imaging WO2009136763 [74]

Chitosan nanoparticle Imaging US2010260686 [75]

Manganese oxide nanoparticle Diagnostic KR20100078508 [76]

Magnetic nanoparticle Imaging KR20070121788 [77]

Lipid nanoparticle Drug delivery WO2008024753 [78]

Lipid nanoparticle Drug delivery WO2008018932 [79]


sis mechanisms that mediate the uptake and efflux of mole-cules. A very important and an unknown fact about the BBB is the metabolic function. The barrier is formed by the ex-pression of metabolizing enzymes such as growth factors, hormones, peptidases, cytochrome P450 enzymes, and monoamine oxidases [63-65]. All of these barrier functions control and regulate both inward and outward transfer of molecules between blood and the brain.

There are several routes for the transport of molecules across the barrier. Paracellular transport of hydrophilic molecules is highly restricted by the tight junctions present between brain endothelial cells. Lipid-soluble molecules with molecular weights below 400 Da are able to cross by transcellular lipophilic diffusion, provided that they are not bound to plasma proteins to a high extent, or form a substrate for a transport system at the BBB.

For a variety of molecules that are essential for brain function, such as amino acids, glucose, peptides, and pro-teins, specific endogenous blood brain barrier transporters exist. These are expressed at both the luminal and the baso-lateral membranes of the endothelium [66]. These transport-ers are generally responsible for the transport of small mole-cules with a fixed size and mass smaller than 600 Da.

Carrier-mediated transcytosis is used for the delivery of nutrients such as glucose, amino acids, and purine bases to the brain. It is substrate selective and only drugs that closely mimic the endogenous carrier substrates will be taken up [67].

Endocytosis at the BBB is effectuated through adsorption or receptor binding. Receptor-mediated endocytosis is initi-ated by the binding of a receptor-specific ligand. Following adsorption or binding, the substance is internalized and transported via the early endosome to the lysosome, or tran-scytosed to the plasma membrane. The only way for larger molecules and particles such as antibodies, lipoproteins, pro-teins and nanoparticles to be transported into the brain is via receptor or adsorptive-mediated endocytosis [41]

Next to these influx systems, many efflux mechanisms exist at the BBB as well. These include P-glycoprotein, MDR-related protein, ABC transporters, and several others. They restrict entry of molecules into the brain by promoting luminal release of compounds and are important in removing harmful substances from the brain, thereby reducing toxic side effects of central nervous system drug metabolites.

RECENT ADVANCES IN THE TREATMENT OF AD WITH NANOPARTICLES

Pharmaceutical agents that are used to treat AD are usu-ally administered orally, such as donepezil, memantine, ri-vastigmine, galantamine and tacrine [7]. However, most of the ingested drugs do not reach the brain in a fully way and are, instead, metabolized totally or partially by the liver. This inefficient utilization of drug may require ingestions of higher drug concentrations that can produce toxic effects in the heart, liver or kidney. Also, many therapeutic agents are poorly soluble or insoluble in aqueous solutions. These drugs provide challenges to deliver them orally or parentally, how-ever these compounds can have significant benefits when formulated through other technologies such as nanoparticles

The greatest obstacle in the treatment of AD with these drugs is often not drug potency, but the physical barriers that render the usual circulatory routes of delivery ineffective [80]. The delivery of drugs to brain is limited by the pres-ence of the BBB. This physical barrier is characterized by tight intracellular junctions (zona occludens) with an absence of fenestrations [41]. Thus, the BBB prevents the uptake of all large molecules and more than 98% of pharmaceutical small-molecule drugs [81]. Furthermore, the BBB expresses high levels of drug efflux pumps such as P-glycoprotein, which actively remove chemotherapeutic drugs from the brain [82]. In addition, diffusion in the brain parenchyma is very weak. Finally, brain tissue is highly sensitive, so only limited doses of therapeutic agents can be used.

Many strategies have been developed to overcome these obstacles. Among these, drug delivery nanosystems have been produced to protect therapeutic agents and improve their biodistribution and therapeutic index. These systems include mainly polymer or lipid-based carriers such as nanoparticles including nanospheres and nanocapsules, mi-celles, dendrimers, nanocrystals, and nanogolds. The tech-nology of nanoparticles represents a promising strategy in which the particles could release therapeutic products immo-bilized and immunoprotected within polymeric and biocom-patible devices [83].

To circumvent the BBB, nanoparticles can be adminis-tered directly into the brain via a bolus injection. This has the advantage of delivering much higher concentrations of drug-loaded nanoparticles to the brain [84-87]. Based on this con-cept, last year we patented the therapeutic use of microen-capsulation of VEGF (vascular endothelial growth factor) over-expression cells [88, 89]. We generated encapsu-lated VEGF-secreting cells and implant them in a transgenic mouse model of AD, the double mutant amyloid precursor protein/presenilin 1 (APP/Ps1) mice, which showed a dis-turbed vessel homeostasis, and of adult C57BL/6 mice. Cra-nial implants of microencapsulated cells secreting VEGF promoted brain vessel formation within the cerebral cortex of adult C57BL/6 mice compared with the non-transfected cell microcapsules-treated group. Two weeks after implanta-tion of encapsulated VEGF secreting cells in adult C57BL/6 mice, vascular density was markedly augmented in the cere-bral cortex in comparison with the control group. This in-creased effect was maintained during all the treatment and was maximal after 3 months. Our findings confirmed previ-ous evidence of a potential therapeutic benefit of VEGF therapy in brain angiogenesis, neuroprotection and cerebro-microvascular exchange of substrates and nutrients [90]. Several studies have reported the successful use of encapsu-lated cell implants that allow diffusion of therapeutic factors into biological fluids, including CSF [91, 92]. According to these data, may be feasible and attractive to implant geneti-cally modified cells into peripheral compartments. We pro-pose that implantation of VEGF microcapsules may have a therapeutic value in the treatment and prevention of brain diseases

One goal of theses findings was to develop the therapeu-tic methodology without alter the BBB and reduce the dam-age of the brain increasing the vascularity at cortical levels and reducing the amyloid-beta deposits [93].


The penetration of a drug into the brain decreases expo-nentially with the distance from the cerebrospinal fluid sur-face, so it is necessary to administer high concentrations of drug into the cerebrospinal fluid compartment. The ependy-mal surface is thus exposed to very high drug concentrations, which can have toxic side effects. The treatments with nanoparticles releasing growth factors are very promising; however there are side effects due to the route of administra-tion. The intracerebroventricular (icv) administration of NGF (nerve growth factor) resulted in axonal sprouting and Schwann cell hyperplasia on the ependymal or arachnoids surface [94]. The icv administration of fibroblast growth factor (FGF)-2 results in periventricular astrogliosis [95]. A promising therapy against AD has been published, consisting in the local and long term administration of CNTF (ciliary neurotrophic factor) using recombinant cells encapsulated with alginate secreting this neurotrophin factor [96, 97].

The major problem with the introduction into brain of nanotechnology is the slower movement of nanoparticles within the brain due to limited diffusion coefficients and backflow of the injection. This is because of the closely packed arrangement of cells in both the gray and white mat-ter microenvironments. Convection enhanced delivery has been used to overcome these problems. Using an external pressure gradient inducing fluid convection in the brain via a surgically implanted catheter, this method allows a greater volume of distribution to be achieved compared with diffu-sion alone [98]. A combination of nanotechnology with the convection enhanced delivery technique has shown promis-ing results in brain diseases.

CeONP can be used to treat or prevent neurodegenerative diseases, including for example AD, PD or HD. In particular, CeONP having an average size of about 2 nm to about 100 nm can be administered in an amount sufficient to block production of hydroxyl or superoxide radicals, block free radical production by amyloid-beta (1-42), neuronal death, [Ca2+] dysfunction in neurons, lipid peroxidation, decrease loss of dopaminergic neurotransmission, or reduce mito-chondrial dysfunction in a cell. CeONP can also be effective in treating conditions involving toxic exposures to com-pounds that induce mitochondrial dysfunction, such as rote-none, cyanide, carbon monoxide, polychlorinated biphenyls and other mitochondrial toxins [99-101].

Another invention relates to nanoparticles containing physiologically active agents. It was patented a new disper-sions containing new nanoparticles within nicotine and co-tinine are particularly suitable for transdermal mode of ad-ministration (DE102007017298). This methodology is mainly published as antismoking and tranquilizer method, however, also showed activity such as neuro-protector in AD animal models [102].

Two different methods it was recently patented using gold nanoparticles. In one of them described an interesting methodology to prepare gold nanoparticles coated with dif-ferent layers a polyelectrolyte its use as carriers intended to cross BBB and as medicament for treatment of AD, PD, HD and prion diseases (CA20092742915, WO2010052665). The outer layer of human albumin is essential for the passage and protection of the BBB and the layer of polyelectrolyte avoid the aggregation of the nanoparticles [103].

In the second patent, gold nanoparticles are using such as diagnostic method for AD and associated dementias (KR101003124). This method confirms the presence of amy-loid beta aggregation due to binding of gold nanoparticles [104]. Other invention relates to the use of metal nanoparti-cles for the diagnosis of AD. In this patent, nanoparticles coupled to metal ions was take up by the macrophages that are associated with a mechanism of inflammation correlated with AD, and are able to cross the BBB (US2010111876). Then the nanoparticles has to be detected by MRI, the in-creasing of this nanoparticles is associated with brain in-flammation and dementia [104].

Also, antibodies can be associated with nanoparticles and could be useful for treatment and diagnosis of AD. Mono-clonal antibodies have been envisioned as useful agents for human therapeutic and diagnostic applications in vivo. Re-cent results from human clinical trials suggest that this po-tential is becoming a reality. Attention is now shifting to the development of methods to produce monoclonal antibodies of a quality acceptable for widespread human use, and in sufficient quantity to be a commercially viable product. Mi-croencapsulation technology has been demonstrated to be suited to the large-scale production of both human and mur-ine monoclonal antibodies of high purity and activity, for use in applications In vivo (US20097473423). It was previously commented the possibility of encapsulating antibodies for the treatment of brain diseases. The same technology using anti-VE-cadherin monoclonal antibodies allowed to open a new alternative for the inhibition of angiogenesis and dem-onstrates the feasibility of using microencapsulated cells as a control-drug delivery system [105, 106]. Also, it the use of human IgM antibodies encapsulated in alginate, it has been recently patented; it has been proved to have a demonstrated activity in the treatment of demyelinating diseases as well as other diseases of the central nervous system that are of viral, bacterial or idiopathic origin, including neural dysfunction caused by spinal cord injury [107].

RECENT ADVANCES IN THE TREATMENT OF PD WITH NANOPARTICLES

PD is a progressive disabling neurodegenerative move-ment disorder without cure. Loss of dopamine causes critical nerve cells in the brain to fire out of control, leaving patients unable to direct or control their movement in a normal man-ner. Currently available therapies can neither arrest nor re-verse the progression of the disease [108]. Several drugs that boost the levels of dopamine or mimic its effects are avail-able for treating PD, but none has surpasses the clinical effi-cacy of its biological precursor L-DOPA [109]. Nowadays, the goal of treatment is to reduce symptoms and to allow a person to function normally, and with as few side effects, as possible. Current treatment options include medications and surgery. There are many effective medications for Parkin-son’s symptoms work by influencing dopamine. The major classes include: levodopa, dopamine agonists, catechol-O-methytransferease (COMP) inhibitors, monoamine oxidase (MAO) B inhibitors, anticholinergics and other medications including amantadine.

In recent years there has been increasing interest in de-veloping drug delivery systems able to target pharmacologi-


cally active molecules in close proximity to their site of ac-tion. Among these, liposomes, polymeric or lipid nanoparti-cles seem to be the most effective in providing tools to inter-act with biological systems at molecular level with a degree of specificity, to provide neuro-protection and neuro-repair.

Actually, increasing interest has been addressed toward the introduction of new therapeutic approaches to obtaining continuous dopaminergic stimulation. The goal of this thera-peutic strategy is to reduce the occurrence and severity of L-DOPA associated motor fluctuations and dyskinesia, and provides good long-term safety and tolerability. This stimu-lation can be achieved by the administration of oral dopa-mine agonists with a long half-life, transdermal, and subcu-taneous delivery or with nanoparticles of dopamine agonists. To allow higher concentrations of L-DOPA to reach the brain and to reduce peripheral side effects, the therapeutic approach provides the concomitant administration of L-DOPA, carbidopa and entacapone that have been developed in tablet form, standard L-DOPA/carbidopa, L-DOPA/ben-serazide, L-DOPA/entacapone, L-DOPA/tolcapone associa-tions or long-acting controlled release formulations, L-DOPA/carbidopa and L-DOPA/benserazide. Alternatively to solid formulations, LD/carbidopa liquid forms have been developed. Furthermore, the authors examine a series of new L-DOPA drugs and non-dopaminergic drugs for PD treat-ment including nanoparticles and biocompatible microparti-cles. Similar strategy was recently developed with the for-mulation of dopamine loaded chitosan nanoparticles. These nanoparticles revealed that were stable allowing to be used such as potential dopamine carrier systems for PD patients [110].

Another recent strategy, and very similar to dopamine loaded chitosan nanoparticles, was developed with apomor-phine distributed with solid lipid nanoparticles. Apomor-phine is a dopamine receptor agonist for treating PD with the main problem that it has very poor oral bioavailability. This system allows the apomorphine delivery via oral ingestion, showing higher bioavailability and a better distribution in the striatum [111]. These experimental results suggest that solid lipid nanoparticles may offer a promising strategy for apo-morphine delivery via oral ingestion.

Nanotechnology hold potential to advance medical treatment through construction of materials with enhanced biological effects, at the atomic scale. Recently, by con-structing nanopharmaceuticals it was developed and patented cerium oxide nanoparticles with a potent antioxidant activity preserving neuronal function in a preclinical model of PD [99-101].

A very interesting project it is going on by Amanda Haes’s group based on develop a novel capillary electropho-resis and nanoparticle-based assay for analysis and separa-tion of plasma samples for PD diagnosis, management, and treatment. This system of capillary electrophoresis needs a small sample volume requirement (can be blood, CSF or brain extracts), allow an excellent separation capability. Samples are injected into the system in the presence of nanoparticles which will serve to significantly enhance both detection and separation efficiencies of the targeted bio-markers [112, 113].

Neurotrophic factors are small proteins necessary for neuron survival and maintenance of phenotype. During the last years they are considered as promising therapeutic tools for neurodegenerative diseases. It is well known that the glial cell line-derived neurotrophic factor (GDNF) and cerebral dopamine neurotrophic factor (CDNF) protects catechola-minergic cells from toxic insults; thus, its potential therapeu-tic applicability in PD has been intensely investigated. In recent years, there have been major advances in the analysis of GDNF signalling pathways in peripheral neurons and em-bryonic dopamine mesencephalic cells. However, the actual physiological role of GDNF in maintaining catecholaminer-gic central neurons during adulthood is only starting to be unravelled, and the mechanisms whereby GDNF protects central brain neurons are poorly known.

Compacted DNA nanoparticles represent a promising non-viral technology that is safe and has been shown to be effective in the lung [114] nasal mucosa [115], eye [116] and brain [117]. Single molecules of plasmid DNA can be com-pacted by polycations to form colloidally stable nanoparti-cles that have the minimum possible theoretical size based on the partial specific volumes of the constituent compo-nents. Based on this nanotechnology, Copernicus Therapeu-tics Inc and Yurek’s group are developing a promising pro-ject with compacted DNA nanoparticles to deliver plasmid DNA to brain cells and produce transgene expression of GDNF. The recombinant plasmid DNA encodes for GDNF and compacted into nanoparticles are injected safely into the brain, and successfully transfected brain cells to over-express GDNF and provide neurotrophic support for dopamine neu-rons [117, 118].

Another study using lactoferrin-modified nanoparticles was also used as a potential non-viral gene vector due to lactoferrin is an interesting molecule key such as brain-targeting and BBB-crossing ability. This study administered via intravenous lactoferrin-modifies nanoparticles with GDNF encapsulated. The results showed that multiple injec-tions of these nanoparticles obtained higher GDNF expres-sion and this gene expression was maintained for a longer time. Even, multiple dosing intravenous administration of this treatment could significantly improve locomotor activ-ity, reduce dopaminergic neuronal loss, and enhance mono-amine neurotransmitter levels on rat model for PD [119]

Other example using other methodology is using encap-sulation procedures, it is the case of microencapsulation of PC12 cells (dopaminergic cell line) and also embryonic grafts of dopaminergic cells were able to ameliorate behav-iours in rat and primates, after the implant of these micro-capsules in experimental parkinsonian models [120, 121].

RECENT ADVANCES IN THE TREATMENT OF LBD WITH NANOPARTICLES

LBD is a neurodegenerative disorder characterized by the presence of Lewy bodies in the affected neurons. The Lewy bodies are cytoplasmic inclusions containing alpha-synuclein protein aggregates. LBD affects an estimated 1.3 million individuals in the United States. The main problem of LBD is that the symptoms can closely resemble other more com-monly known diseases like AD and PD; therefore it is cur-rently widely under diagnosed. LBD is a term for two related


diagnoses; it refers to both PD dementia and dementia with Lewy bodies. A poorly understood feature of LBD is loss of sympathetic nerves in the heart and other organs, manifest-ing as orthostatic hypotension. The earliest symptoms of these two diseases, LBD and PD, differ but reflect the same underlying biological changes in the brain. Over time, people with both diagnoses will develop very similar cognitive, physical, sleep, and behavioural symptoms [122].

Patients with LBD may present a unique set of symptoms and challenges to family caregivers compared with other types of dementia. Prominent difficulties include motor im-pairment, activities of daily living disability, recurrent be-havioural and emotional problems. Cholinesterase inhibitors are considered the standard treatment for cognitive symp-toms in LBD. These medications were developed to treat AD. However, some researchers believe that people with LBD may be even more responsive to these types of medica-tions than those with AD. Movement symptoms may be treated with a PD medication called levodopa. However, some people with LBD are extremely sensitive or may react negatively to certain medications used to treat AD or PD.

Abnormally accumulated alpha-synuclein is a pathologi-cal hallmark of LBD. However, it is not well understood whether and how abnormal accumulation of alpha-synuclein leads to cognitive impairment or dementia in LBD [123]. Furthermore, it is not known whether targeted removal of alpha-synuclein pathology can reverse cognitive decline. Key treatment targets include cognitive and functional im-pairments, neuropsychiatric symptoms including intense and persistent visual hallucinations, and parkinsonism. Six-month, placebo-controlled randomized controlled trials of the cholinesterase inhibitor rivastigmine have indicated modest but significant benefits in cognition, function, global outcome and neuropsychiatric symptoms in LBD. The evi-dence base for other cholinesterase inhibitors from clinical trials is inconclusive. More recent clinical trials with me-mantine in PD and LBD patients indicate a benefit with re-gard to global outcome, with some suggestion of a specific benefit with respect to sleep disturbance [124].

There is no effective therapy for LBD, thus nanotechnol-ogy could not developed any effective nano-carrier to treat it. The unique efforts of this field are to degraded or alter the abnormal alpha-synuclein accumulation in the brain. The inhibition of fibril formation is a potential therapeutic strat-egy for these conditions. There is several experimental therapies using nanoparticles to clear or prevent the synu-clein pathology to treat PD but can be used also in LBD pa-thology.

Vasogen Inc. is working with a preparation of phosphol-ipid nanoparticles incorporating phosphatidylglycerol that has been shown to have neuroprotective effects in PD and LBD. This drug increasing the proteosome system prevents the deficits in motor coordination and dopamine observed in a proteasome inhibitor rat model of PD [125].

Other potential therapeutic strategy is investigated with polyamidoamine (PAMAM) dendrimers as inhibitors of fi-bril formation in vitro. Although is the first step in the devel-opment of new therapy wit this dendrimer, the PAMAM dendrimer caused an inhibition of fibrillation of alpha-

synuclein and could be a potential new drug for PD and LBD [126].

RECENT ADVANCES IN THE TREATMENT OF FTD WITH NANOPARTICLES

FTD is late-onset neurodegenerative disorders that are associated with mutations in the TARDBP gene. The product of this gene, TDP-43, has also been identified as the main component of the intracellular inclusions typical of most cases of FTD. This dementia is progressive and gradually destroys the ability to behave appropriately, empathize with others, learn, reason, make judgments, communicate and carry out daily activities. In people under age 60, FTD is the most common cause of dementia and affects as many people as AD in the 45-64 age group. FTD is a clinical syndrome associated with shrinking of the frontal and temporal anterior lobes of the brain. Signs and symptoms vary, depending upon the portion of the brain affected. There are several forms of the disease that lead to slightly different behav-ioural, language and motor symptoms. Due to the symptoms, FTD can be mistaken for AD, PD or a primarily psychiatric disorder like depression, manic-depression, obsessive-compulsive disease or schizophrenia [127].

At cellular level, FTD is marked by cell loss and scarring in the frontal lobes, parts of the temporal lobes and the deeper brain structures that link to them. The tissue loss re-sults from changes in the proteins that normally help cells function. Unlike AD, the brain tissue of people with FTD does not show plaques and rarely shows tangles. Brain tissue from patients with FTD often shows cellular inclusions in neurons named Pick body. These inclusions stain positively for a Tau protein. About 40% of people with FTD have these tau-positive inclusions. A second type of cellular inclusion found in people with FTD is made up of two other proteins called ubiquitin and TDP-43. Ubiquitin is a protein that is involved with clearing waste products from the cell, while TDP-43 is a protein involved with making proteins from the instructions contained in DNA [128].

Unfortunately, there is no way to reverse the damage caused by FTD yet, but many medications and lifestyle chan-ges can help relieve the symptoms. Furthermore, researchers are actively searching for new treatments and running clini-cal trials to test promising new medications.

Recent evidence suggests that TDP-43 is essential for proper development and involved in several fundamental cellular processes, including gene transcription, RNA proc-essing, and the spatial regulation of mRNA translation. Pathogenic TARDBP mutations that impair TDP-43 function could therefore be related to neuronal degeneration in FTD [129]. At the present time there is no known treatment for diseases involving TDP-43 proteinopathies. As TDP-43 pa-thology is throughout the brain in FTD, recently it was pat-ented a new therapy using adenovirus and gene delivery for widespread TDP-43 expression in the brain and spinal cord (US20110203007). Accordingly, this invention relates to the fields of novel assays for the study of neurodegenerative diseases and in the future could be combined with nanotech-nology for the delivery of the gene into brain. More specifi-cally, this invention describes the use of viral delivery of


TDP-43 to create assays of diseases involving TDP-43 such as FTD [130].

RECENT ADVANCES IN THE TREATMENT OF VD WITH NANOPARTICLES

VD is widely considered the second most common type of dementia. It develops when impaired blood flow to parts of the brain deprives cells of food and oxygen. There is also a form in which a series of very small strokes, or infarcts, block small blood vessels. Individually, these strokes do not cause major symptoms, but over time their combined effect becomes noticeable. This type is referred to as vascular cog-nitive impairment (VCI) or multi-infarct dementia [131]. The molecular perspective on VD is rather limited; the general concept of this type of cognitive impairment has derived from clinical and imaging findings and is correlated, at the cellular level, with neuronal death and the sudden interrup-tion of neuronal networks. The main pathological changes leading to different forms of VD take place in both large (atherosclerosis and thrombosis) and small (lipohyalinosis and fibrosis) cerebral vessels, secondary to common vascular risk factors, such as hypertension, diabetes mellitus, and dyslipidemia. The reduction in cerebral blood flow starts early during vascular disease [132] and, therefore, a major vascular event can be preceded by a variable period of chronic hypoxia. As a result, the brain cellular microenvi-ronment might change and adaptive processes may lead to cellular malfunction, rather than cellular death [133].

The diagnosis may be clearest when symptoms appear soon after a single major stroke blocks a large blood vessel and disrupts the blood supply to a significant portion of the brain. This situation is sometimes called post-stroke demen-tia.

Symptoms of VD can vary, depending on the specific brain areas deprived of blood. Impairment may occur in steps, where there is a fairly sudden, noticeable change in function, rather than the slow, steady decline usually seen in AD. VD symptoms include: confusion, trouble paying atten-tion and concentrating, reduced ability to organize thought or actions, difficulty deciding what to de next, problems with memory, restlessness and agitation, etc.

But VD can also develop very gradually, just like AD. Studies show that people with dementia symptoms usually have brain changes typical of more than one type. Because VD is closely tied to diseases of the heart and blood vessels, many experts consider it the most potentially treatable form: monitoring of blood pressure, weight, blood sugar and cho-lesterol should begin early in life. There is not yet a known cure for VD, so prevention is important. The best way to prevent VD is to lower the risk of stroke. This means getting high blood pressure under control, avoiding cigarettes, and controlling cholesterol levels and diabetes. The FDA has not, as yet, approved any medications for the treatment of VD. However, a number of medications used to treat the cognitive symptoms of AD appear to work for VD, too (cho-linesterase inhibitors and memantine).

At the same manner that other neurodegenerative disease there is no effective therapy for VD, thus nanotechnology could not developed any effective nano-carrier to treat it.

The unique efforts of this field are to detect different markers of hypoxia such as hypoxia inducible factor-1 (HIF-1). HIF-1 was used experimentally as a biomarker of hypoxia in the cortex of young and old spontaneously hypertensive rats [134]. Interestingly, the increase in HIF1 was documented only in aged animals, along with an imbalance between mi-crovessels and astrocytes at the level of the neurovascular unit. In hypoxic conditions, HIF-1 is upregulated, translo-cates into the nucleus, and binds to hypoxia responsive ele-ments of target genes, such as vascular endothelial growth factor (VEGF), glucose transporter-1 (GLUT1), lactate de-hydrogenase (LDH), erythropoietin (Epo), and nitric oxide synthase (NOS). This molecular pathway can open new po-tential therapies combining growth factors and nanotechnol-ogy.

Using this concept our laboratory generated and patented (WO2010089442 and WO2010010223) new encapsu-lated VEGF-secreting cells and implant them in a transgenic mouse model of AD, which showed a disturbed ves-sel homeostasis [89, 90]. Cranial implants of microencapsu-lated cells secreting VEGF promoted brain vessel formation within the cerebral cortex of adult C57BL/6 mice compared with the non-transfected cell microcapsules-treated group. Two weeks after implantation of encapsulated VEGF secret-ing cells in adult C57BL/6 mice, vascular density was mark-edly augmented in the cerebral cortex in comparison with the control group. This increased effect was maintained during all the treatment and was maximal after 3 months. Our find-ings confirmed previous evidence of a potential therapeutic benefit of VEGF therapy in brain angiogenesis, neuroprotec-tion and cerebromicrovascular exchange of substrates and nutrients [93].

Similar invention was also recently patented using nanoparticles composed of chitosan, poly-glutamic acid, and at least one protein drug or bioactive agent characterized with a positive surface charge and their enhanced permeabil-ity for paracellular protein drug and bioactive agent delivery. This protein drug can be different angiogenic and neurotro-phic growth factors such as VEGF, HIF1, and IGF-I [135]. Other invention provides slow releasing nanoparticles of huperzine A for curing specifically AD and VD [136].

RECENT ADVANCES IN THE TREATMENT OF PRION DISEASES WITH NANOPARTICLES

Prion diseases, also known as transmissible spongiform encephalopathies (TSE), are a family of fatal neurodegenera-tive disorders [137-140]. Prion diseases include Scrapie in sheep, Bovine Spongiform Encephalopathy (BSE) in cattle, Chronic Wasting Disease (CWD) in deer, elk and kuru, Creutzfeldt-Jakob disease (CJD), Fatal Familiar Insomnia (FFI) and Gerstmann-Straussler-Scheinker syndrome (GSS) in humans. Clinically disease is characterised by dementia and motor dysfunction, and neuropathologically by amyloid deposition (in the form of prion protein), spongiform changes in the brain (holes in the tissue with resultant spongy architecture due to vacuole formation in neurons) and neuronal loss. However, the clinical symptoms can vary between and within the different prion syndromes. The pro-gression of prion diseases is rapid, after the initial onset of


symptoms death normally ensues within 1-3 years [141, 142].

The mature human cellular prion protein denoted PrPc consists of 209 amino acids. Invariably, all of these diseases involve the modification of the endogenous and functional PrPC into a nonfunctional but much more stable form (PrPSc) giving rise to the so-called amyloid plaques in the brain and other nervous tissues [143]. Prion diseases ei-ther occur spontaneously without explanation, or are ac-quired through exposure to prion-infected tissue, or are in-herited through mutations of the prion protein gene (PRNP).

The “protein-only” hypothesis is the most widely ac-cepted model that explains the nature and replication of pri-ons and the transmission of the disease. Prions are devoid of nucleic acid and seem to be composed exclusively of the scrapie isoform of the prion protein designated PrPSc. Solu-ble, protease-sensitive PrPC is converted into PrPSc, which is protease-resistant, through a process whereby a portion of its a-helical and coil structure is refolded into a -sheet struc-ture. Consequently, PrPSc exhibits a high propensity to ag-gregate. It is thought that PrPSc acts as a template upon which PrPc is refolded into the PrPSc isoform through a process possibly facilitated by another protein or molecular chaperone. It is thought that PrPSc is responsible for the neu-rodegenerative processes in prion diseases.

Detection of its presence for contention in cattle or diag-nosis in humans or blood transfusion banks [144] is very difficult even by state of the art immunological methods such as fluorescence immunoassay, RIA, or ELISA [145] or protein misfolding cyclic amplification, which can be. The development of unique detection techniques capable of accu-rately detecting/diagnosing the presence of prions in the blood or serum of infected but not clinically sick animals to avoid the dissemination of the disease is therefore much needed. Recently it was published a promising method to detect prions in biological fluids before to the appearance of the first symptoms [146].

The major challenge of prion disease diagnosis at the presymptomatic stage is how to sensitively or selectively discriminate and detect the minute quantity of disease asso-ciated prion protein isoform in complex biological systems such as serum and brain homogenate. In this contribution, there were published different strategies using different as-pects of the nanotechnology with quantum dots [147, 148] and suparamagnetic nanoparticles [149].

Magnetic nanoparticle capture presents an interesting and important utility to decontaminate biological products de-rived from potentially contaminated sources. Other methods, such as sodium hydroxide, sodium hypochlorite, and phos-photungstic acid treatments, destroy or remove prions but also damage the material of interest. In contrast, magnetic nanoparticles capture PrPSc with specificity [149]. Obvi-ously, the developing of this technique can be applied also to prion detection in biological samples.

Calvo et al. employed a novel strategy by using PEGy-lated polycyanoacrylate nanoparticles as vector for drug de-livery in experimental model of prion disease [150]. The work showed that these nanoparticles produced a higher up-

take by the spleen and the brain which are the both target tissue of PrP.

To date, there have been no reports showing that any compound can reverse or ameliorate prion disease progres-sion following the onset of neurological symptoms. How-ever, several patents were published using nanoparticles to treat different prion disease: US2011262546, WO201015-1085 and WO2010121000. The current therapeutic chal-lenges are to stop the further production of PrPSc molecules, and to remove the PrPSc molecules that accumulated during the pre-symptomatic phase of the disease. Given the extreme chemical and physical resistance of infectious prions to inac-tivation, accomplishing the latter task without disrupting normal cellular physiology would appear daunting. How-ever, in vitro studies with a number of different nanoparticles suggest that this technology might be able to inactivate or eliminate PrPSc molecules though unique interactions that do not compromise cell viability [151-154].

CURRENT & FUTURE DEVELOPMENTS

Neurodegenerative diseases are one of the most serious health problems in the industrialized world. The use of nanotechnology in neurodegenerative medicine and more specifically drug delivery is set to spread rapidly. Nanotech-nology has proven to have great potential for providing nan-otherapeutics modalities to limit and reverse the neuropa-thology of neurodegenerative diseases, such as AD and PD, by supporting and promoting functional regeneration of damaged neurons, providing neuroprotection, and facilitating the delivery of neuroactives such as drugs, growth factors, genes and cells across the BBB Table 3. One of the main problems to recover the brain function is that the neurons are relatively difficult targets for genetic manipulation, present-ing obstacles for both basic research and therapeutic devel-opment. Based on this aspect, biomaterials are playing an increasingly important role in the development of novel, potentially efficacious approaches to brain treatment and repair. Programmable biomaterials enable and augment the targeted delivery of drugs into the brain and allow cell trans-plants to be effectively delivered and integrate into the brain, to serve as delivery vehicles for therapeutic proteins, and rebuild damaged circuits.

Nanoparticles can easily enter brain capillaries before reaching the surface of the brain microvascular endothelial cells, under the condition that the surface of these colloids is modified in a proper way (i.e., by PEG). The prolonged blood circulation of these surface-modified nanoparticles enhances exposure of the BBB, which favours interaction and penetration into brain endothelial cells. Passage of the BBB may also be achieved by masking certain drug charac-teristics preventing or limiting binding to cellular efflux sys-tems like p-glycoprotein or via an LDL receptors-dependent pathway forming a complex with LDL in the blood stream. Other promising routes for reaching the brain, circumventing the BBB, may be via migration along the olfactory or tri-geminal nerve endings after deposition on the olfactory mu-cosa in the nasal region. In order to increase the specific up-take via the inhalation route nanoparticles have been func-tionalized by conjugation with bioactive ligands-lectins to the surface of PEG-PLA nanoparticles. However, it needs to


Table 3. Biological approaches of central nervous system drug delivery primarily emanate from the understanding of the physiologi-

cal and anatomical structures of the BBB transportation. Further the new nanoparticles developed to enter into brain also it

is very important develop new available drugs that can be conjugated with the nanoparticles. Many available approaches

are developing the pharmaceutical companies such as conjugation of a drug with antibodies or biological methods for tar-

geting exploit ligands in the form of sugar or lectins, which can be directed to specific receptors found on cell surfaces. Here

in this table we enumerate the recent patents of new neurotherapeutic where nanoparticles are developing in different neu-

rodegenerative diseases. AD: Alzheimer’s disease, PD: Parkinson’s disease, HD: Huntington's disease, VD: Vascular demen-

tia, LBD: Lewy Body dementia, FTD: Frontotemporal dementia and prion diseases

Disease Reference or Patent Principle active in the nanoparticles

AD US20056926888 CNTF

AD [70] NGF

AD [71] FGF-2

AD [72] CNTF

AD WO2007002662 CeONP

AD and PD US2009092671 CeONP

AD WO2009052295 CeONP

AD DE102007017298 Nicotine

AD KR101003124 Ab for diagnosis

AD US2010111876 Macrophages

AD US20097473423 VE-Cadherin

AD, PD, HD and Prion diseases CA20092742915 Albumin

AD, PD, HD and Prion diseases WO2010052665 Albumin

AD and VD WO2010089442 VEGF

AD and VD WO2010010223 VEGF

AD and VD [111] Huperzine A

PD [85] Dopamine

PD [86] Apomorphine

PD [89, 90, 91, 92] DNA microparticles

PD [92, 93] GDNF

PD [94] lactoferrin

PD [95, 96] PC12 cells

LBD [100] Phosphatidylglicerol

LBD [101] PANAM dendrimers

FTD US20110203007 TDP43

VD [110] VEGF, HIF1, IGF-I

Prion diseases [122, 123] Quantum dots

Prion diseases [124] Suparamagnetic NP

Prion diseases [125] PEGylataed NP

Prion diseases WO2010121000 Clearance of PrPSc

Prion diseases WO2010151085 Clearance of PrPSc

Prion diseases US2011262546 Clearance of PrPSc


be stated that both passage of the BBB and the olfactory route only account for up to 2% nanoparticles uptake, and its efficacy with regard to drug delivery needs to make consid-erable increments before use.

However, many of these approaches are gaining momen-tum because nanotechnology allows greater control over material-cell interactions that induce specific developmental processes and cellular responses including differentiation, migration, and outgrowth. The new generation of nanoparti-cles might control the delivery of drugs both by prolonging drug circulation and by targeting the drug to the site of ac-tion in a specific manner. Further experiments are necessary to the better comprehension of the mechanisms which man-age these different nanoparticle-mediated transport of the drugs to the brain, these nanoparticles may be helpful in the treatment of brain diseases, because they offer clinical ad-vantages such as decreased drug dose, reduced drug side effects, increased drug viability, non-invasive routes of ad-ministration, and improved patient quality of life.

Considering the rapidly ageing western countries popula-tion and the resulting increase in the incidence of neurode-generative diseases, there is an urgent need to address an urgent search for new and promising therapies presented by nanoparticles towards neurodegenerative diseases. New treatments for disease progression and more effective symp-tomatic therapies are urgently required. The challenge in-volved in the discovery and development of novel drug tar-gets for the treatment of neurodegenerative diseases is a ma-jor task for both the academic and pharmaceutical communi-ties. This area represents the most important unmet medical need in the treatment of central nervous system disease.

ACKNOWLEDGMENTS

We thank Tania Vazquez for editorial assistance. This work was supported by grants from Xunta de Galicia (IN-CITE2009, 09CSA051905PR), Ministerio de Ciencia e In-novación (PI11/00842) and “Isidro Parga Pondal” pro-gramme.

CONFLICT OF INTEREST

None of the authors of this manuscript have any financial interest that has influenced the results or interpretation of this manuscript.

REFERENCES

[1] OECD. Dementia Prevalence, in OECD, Health at a Glance: Europe 2010, OECD Publishing 2010; 54-55.

[2] Forlenza O, Diniz B, Gattaz W. Diagnosis and biomarkers of pre-dementia in Alzheimer’s disease. BMC Medicine 2010; 8:89.

[3] Soto C. Unfolding the role of protein misfolding in neurodegenera-tive diseases. Nat Rev Neurosci 2003; 4: 49-60.

[4] Bertram L, Tanzi R. The genetic epidemiology of neurodegenera-tive disease. J Clin Invest 2005; 115: 1449-57.

[5] Ferri CP, Prince M, Brayne C, Brodaty H, Fratiglioni L, Ganguli M, et al. Global prevalence of dementia: A Delphi consensus study.

Lancet 2005; 366: 2112-7. [6] Morgan D. Immunotherapy for Alzheimer’s disease. J Intern Med

2011; 269: 54-63. [7] Pasic MD, Diamandis EP, McLaurin J, Holtzman DM, Schmitt-

Ulms G, Quirion R. Alzheimer disease: Advances in pathogenesis, diagnosis and therapy. Clin Chem 2011; 57:5.

[8] Morley JF, Hurtig HI. Current understanding and management of

Parkinson disease: Five new things. Neurology 2010; 75: 9-15. [9] Glenner GG, Wong CW. Alzheimer’s disease: Initial report of the

purification and characterization of a novel cerebrovascular amy-loid protein. Biochem Biophys Res Commun 1984; 120: 885-90.

[10] Pike CJ, Walencewicz AJ, Glabe CG, Cotman CW. In vitro aging of beta amyloid protein causes peptide aggregation and neurotoxic-

ity. Brain Res 1991; 563: 311-4. [11] Lorenzo A, Yankner BA. Beta amyloid neurotoxicity requires fibril

conformation and is inhibited by congo red. Proc Natl Acad Sci USA 1994; 91: 12243-7.

[12] Walker LC, Rosen RF, LeVine H. Diversity of Abeta deposits in the aged brain: A window on molecular heterogeneity? Rom J

Morphol Embryol 2008; 49:5-11. [13] Kuo YM, Kokjohn TA, Beach TG, Sue LI, Brune D, Lopez JC, et

al. Comparative analysis of amyloid beta chemical structure and amyloid plaque morphology of transgenic mouse and Alzheimer’s

disease brains. J Biol Chem 2001; 276: 12991-8. [14] Santos E, Zarate J, Orive G, Hernandez R, Pedraz J. Biomaterials

in cell microencapsulation. Adv Exp Med Biol 2010; 670: 5-21. [15] Chang TM. Semipermeable microcapsules. Science 1964; 146:

524-5. [16] Jain RA. The manufacturing techniques of various drug loaded

biodegradable poly(lactide-co-glicolide) (PLGA) devices. Biomate-rials 2000; 21: 2475-90.

[17] Spuch C, Antequera D, Portero A, Orive G, Hernandez RM, Molina JA, et al. The effect of encapsulated VEGF-secreting cells

on brain amyloid load and behavioural impairment in a mouse model of Alzheimer’s disease. Biomaterials 2010; 31: 5608-18

[18] Spuch C, Navarro C. The therapeutic potential of microencapsulate implants: Patents and clinical trials. Rec Pat Endocrine, Metabolic

& Immune Drug Discovery 2010; 4: 59-68. [19] Kincses ZT, Vecsej L. Pharmacological therapy in Parkinson dis-

ease: Focus on neuroprotection. CNS Neurosci Ther 2011; 17: 345-67.

[20] Gustavsson A, Svensson M, Jacobi F, Allqulander C, Alonso J, Beghi E, et al. Cost of disorders of the brain in Europe 2010. Eur

Neuropsychopharmacol 2011; Sep 12. In press. [21] Henchcliffe C, Severt WL. Disease modification in Parkinson’s

disease. Drugs Aging 2011; 28: 605-15. [22] Osona-Nuñez L, Guisado-Macias JA, Pons M. Cognition and Lewy

body disease. Actas Esp Psiquiatr 2011; 39: 267-70. [23] Ho GJ, Liang W, Waragai M, Sekiyama K, Masliah E, Hashimoto

M. Bridging molecular genetics and biomarkers in lewy body and related disorders. Int J Alzheimer Dis 2011; 2011: 842475.

[24] Jellinger KA, Attems J. Prevalence and pathology of dementia with Lewy bodies in the oldest old: a comparison with other dementing

disorders. Dement Geriatr Cogn Disord 2011; 31: 309-16. [25] Seeley WW, Zhou J, Kim EJ. Frontotemporal dementia: What can

the behavioural variant teach us about human brain organization? Neuroscientist 2011; Jun 13, in press.

[26] Gotz J, Eckert A, Matamales M, Ittner LM, Liu X. Modes of Abeta toxicity in Alzheimer’s disease. Cell Mol Life Sci 2011; 20: 3359-

75. [27] Rohrer JD. Structural brain imaging in frontotemporal dementia.

Biocheim Biophys Acta 2011; Jul 30, in press. [28] Portugal Mda G, Marinho V, Laks J. Pharmacological treatment of

frontotemporal lobar degeneration: systemic review. Rev Bras Psi-quiatr 2011; 33: 81-90.

[29] Enciu AM, Constantinescu SN, Popescu LM, Muresanu DF, Po-pescu BO. Neurobiology of vascular dementia. J Aging Res 2011;

2011: 401604. [30] Lasiene J, Yamanaka K. Glial cells in amyotrophic lateral sclerosis.

Neurol Res Int 2011; 2011: 718987. [31] Lo DC, Hughes RE. Neurobiology of Huntington’s disease: appli-

cations to drug discovery. Neurobiology of Huntington’s disease, 2nd edition, Boca Raton: CRC Press; 2011. Frontiers in Neurosci-

ence ISBN: 978-0-8493-9000 [32] Perlman SL. Spinocerebellar degenerations. Handb Clin Neurol

2011; 100: 113-140. [33] Teive HA. Spinocerebellar ataxias. Arq Neuropsiquitr 2009; 67:

1133-42. [34] Gambetti P, Cali I, Notari S, Kong Q, Zou WQ, Surewicz WK.

Molecular biology and pathology of prion strains in sporadic hu-man prion diseases. Acta Neuropathol 2011; 121:79-90.


[35] Wadsworth JD, Collinge J. Molecular pathology of human prion

disease. Acta Neuropathol 2011; 121: 69-77. [36] Duncan R. The dawning era of polymer therapeutics. Nat Rev Drug

Disc 2003; 2: 347-60. [37] Spuch C, Navarro C. Liposomes for targeted delivery of active

agents against neurodegenerative diseases: Alzheimer’s disease and Parkinson’s disease. J Drug Deliv 2011; in press.

[38] Spuch C, Navarro C. Cell Microencapsulation Implants into the Central Nervous System. Rec Pat Nanomed 2011; 1: 60-7.

[39] Spuch C, Navarro C. The therapeutic potential of cell encapsulation technology for drug delivery in neurological disorders. Edited by

Rosario Pignatello. Published by Intech. Biomaterials science and engineering 2011; 20: 403-20. ISBN 978 953 307 609 6.

[40] Dietrich M, Spuch C, Antequera D, Rodal I, De Yebenes JG, Molina JA, et al. Megalin mediates the transport of leptin across

the blood-CSF barrier. Neurobiol Aging 2008; 29: 902-12. [41] Spuch C, Navarro C. Transport Mechanisms at the Blood-

Cerebrospinal-Fluid Barrier: Role of Megalin (LRP2). Rec Pat En-doc Metab Immun Drug Discov 2010; 4: 190-205.

[42] Koziara JM, Lockman PR, Allen DD, Mumper RJ. The blood brain barrier and brain drug delivery. J Nanosci Naniotechnol 2006; 6:

2712-35. [43] Day-Lollini PA, Stewart GR, Taylor MJ, Johnson RM, Chellman

GJ. Hyperplastic changes within the leptomeninges of the rat and monkey in response to chronic intracerebroventricular infusion of

nerve growth factor. Exp Neurol 1997; 145: 24-37. [44] Olivier JC. Drug transport to brain with targeted nanoparticles.

NeuroRx 2005; 2: 108-119. [45] Lockman PR, Koziara J, Roder KE, Paulson J, Abbruscato TJ,

Mumper RJ, et al. In vivo and in vitro assessment of baseline blood-brain barrier parameters in the presence of novel nanoparti-

cles. Pharm Res 2003; 20: 705-13. [46] Gref R, Domb A, Quellec P, Blunk T, Muller RH, Verbavatz JM, et

al. The controlled intravenous delivery of drugs using PEG-coated sterically stabilized nanospheres. Adv Drug Deliv Rev 1995; 16:

215-33. [47] Alyautdin R, Gothier D, Petrov V, Kharkevich D, Kreuter J. Anal-

gesic activity of the hexapeptide dalargin adsorbed on the surface of polysorbate 80 coated poly(butyl cyanocrylate) nanoparticles.

Eur J Pharm Biopharm 1995; 41: 44-8. [48] Senior J, Gregoriadis G. Is half life of circulating small unilamellar

liposomes determined by changes in their permeability? FEBS lett 1982; 145: 109-114.

[49] Kreuter J, Alyautdin R, Kharkevich D, Ivanov A. Passage of pep-tides through the blood brain barrier with colloidal polymer parti-

cles (nanoparticles). Brain Res 1995; 674: 171-4. [50] Grislain L, Couvreur P, Lenaerts V, Roland M, Deprez-

Decampeneere D, Speiser P. Pharmacokinetics and distribution of a biodegradable drug carrier. Int J Pharm 1983; 15: 335-45.

[51] Orive G, Anitua E, Pedraz JL, Emerich DF. Biomaterials for pro-moting brain protection, repair and regeneration. Nat Rev Neurosci

2009; 10: 682-92. [52] Pardridge WM. Biophamarceutical drug targeting to the brain. J

Drug Target 2010; 18: 157-67. [53] Pardridge WM. Drug transport in brain via the cerebrospinal fluid.

Fluids Barriers CNS 2011; 8: 7-9. [54] Li Y, Pei Y, Zhang X, Gu Z, Zhou Z, Yuan W, et al. PEGylated

PLGA nanoparticles as preparation carriers: synthesis, preparation and biodistribution in rats. J Control Release 2001; 71: 203-211.

[55] Blanco MD, Alonso MJ. Development and characterization of protein loaded poly(lactide-co-glycolide) nanospheres. Eur J Pharm

Biopharm 1997; 43: 287-94. [56] Catena R, Santos E, Orive G, Hernandez RM, Pedraz JL, Calvo A.

Improvement of the monitoring and biosafety of encapsulated cells using the SFGNESTGL triple repórter system. J Control Release

2010; 146: 93-8. [57] Chen W, Zhan C, Gu B, Meng Q, Wang H, Lu W, Hou H. Targeted

brain delivery of itraconazole via RVG29 anchored nanoparticles. J Drug Target 2011; 19: 228-234

[58] Malavolta L., Cabral FR. Peptides: Important tools for the treat-ment of central nervous system disorders. Neuropeptides 2011; 45:

309-316. [59] Rae CS, Wei Khor I, Wang Q, Destito G, Gonzalez MJ, Singh P, et

al. Systemic trafficking of plant virus nanoparticles in mice via the oral route. Virology 2005; 343: 224-35.

[60] Elder A, Gelein R, Silva V, Feikert T, Opanashuk L, Carter J, et al.

Translocation of inhaled ultrafine manganese oxide particles to the central nervous system. Environ Health Perspect 2006; 114: 1172-

8. [61] Oberdorster G, Oberdorster E, Oberdorster J. Conceps of nanopar-

ticle dose metric and response metric. Environ Health Perspect 2007; 117: 290.

[62] Semmler-Behnke M, Kreyling WG, Lipka J, Fertsch S, Wenk A, Takenaka S, et al. Biodistribution of 1.4 and 18 nm gold particles

in rats. Small 2008; 4: 2108-11. [63] Beaton, A., Catchpoleian, R. Encapsulation of biologically active

agents. TW2010006495 (2010). [64] Catchpoleian, R., Wayne, G.G., Papanicolau, I. Encapsulation of

biologically active agents. WO2009135853 (2009). [65] Madhavan, N., Zainulabedin, S. Magnetic nanodelivery of thera-

peutic agents across the blood braion barrier. US2011213193 (2011).

[66] Yehuda, I. Intracochlear drug delivery to the central nervous sys-tem. US2011213193 (2011).

[67] McDonough, J., Dixon, H., Cabell, L. Nanoparticles for drug deliv-ery to the central nervous system. US2011195125 (2011).

[68] Krol, S., Lopez-Biota J. polyelectrolyte encapsulated gold nanopar-ticles capable of crossing blood brain barrier. US2011111040

(2011). [69] Sigalov, A. Methods and composition for targeted imaging.

WO2011044545 (2011). [70] Wayne, G.G., Catchpoleian, R., Papanicolau, I., Beaton, A. Encap-

sulation of biologically active agents. MX2010012137 (2010). [71] Chuanhua, L., Lei, W. Preparation of brain targeting chuanxiogzine

oral oil package oil nano-emulsion. CN101884614 (2010). [72] Chen, P., Yang, J., Zhuang, D. Drug delivering material taking

vitamin C as hydrophilic fragments and preparation method thereof. CN101701061 (2010).

[73] Hemant, S. Dendritic conjugates and methods of use. WO2009142754 (2009).

[74] Jin, W.C., Jae-Hyun, L. Nanoparticles for penetration of blood brain barrier. WO2009136763 (2009).

[75] Miqin, Z., Conroy, S., Omid, V., Narayan, B.I. Nanoparticles for brain tumor Imaging. US2010260686 (2010).

[76] Ho, L.G., Ming, C.Y., Jeong, K.T., Young, P.J., Tae, W.S. Coated manganese oxide nanoparticles by biocompatible ligand and syn-

thesizing thereof. KR20100078508 (2010). [77] Massoud, A., Jerome, E. Functionalized magnetic nanoparticles

and methods of use thereof. KR20070121788 (2007). [78] Jayanth, P., Mahesh, C. Lipid derived nanoparticles for brain tar-

geted drug delivery. WO2008024753 (2008). [79] Bright, C., Bright, R., Churchill, E., Leong, K.W., Mochly-Rosen,

D. Method and use of nano-scale devices for reduction of tissue in-jury in ischemic and reperfusion injury. WO2008018932 (2008).

[80] Ghersi-Egea JF, Leninger-Muller B, Suleman G, Siest G, Minn A. Localization of drug-metabolizing enzyme activities to blood-brain

interfaces and circumventricular organs. J Neurochem1994; 62:1089-96.

[81] Ghersi-Egea JF, Leininger-Muller B, Cecchelli R, Fenstermacher JD. Blood-brain interfaces: relevance to cerebral drug metabo-

lism. Toxicol Lett 1995; 82: 645-53. [82] Abbott NJ. Prediction of blood-brain barrier permeation in drug

discovery from in vivo, in vitro and in silico models. Drug Discov Today: Technologies 2004; 1: 337-463.

[83] Boer AB, Lange EL, Sandt ICJ, Breimer DD. Transporters and the blood-brain barrier (BBB) Int J Clin Pharmacol Ther 1998; 36:14-

15. [84] Boer AG, Gaillard PJ. Drug targeting to the brain. Annu Rev

Pharmacol Toxicol 2007; 47: 323-55. [85] Pardridge WM. Molecular biology of the blood brain barrier. Mol

Biotechnol 2005; 30: 57-70. [86] Pardridge WM. Molecular biology of the blood brain barrier.

Methods Mol Med 2003; 89: 385-99 [87] Golden PL, Pollack GM. Blood brain barrier efflux transport. J

Pharm Sci 2003; 92: 1739-53. [88] Orive G, Hernández RM, Gascon AR, De Vos P, Hortelano G,

Hunkeler D, et al. Cell encapsulation: Promise and progress. Nat Med 2003; 9: 104-7.

[89] Orive, G., Hernandez, RM., Spuch, C., Antequera D, Carro E, Pedraz JL. Method for treating neurodegenerative diseases.

WO2010089442 (2010).


[90] Hernandez, R.M., Orive, G., Spuch, C., Antequera, D., Carro E,

Pedraz JL, Use of microparticles containing genetically modifies cells in the treatment of neurodegenerative diseases.

WO2010010223 (2010). [91] Aebischer P, Schluep M, Déglon N, Joseph JM, Hirt L, Heyd B, et

al. Intrathecal delivery of CNTF using encapsulated genetically modified xenogeneic cells in amyotrophic lateral sclerosis patients.

Nat Med 1996; 2: 696-9. [92] Sieving PA, Caruso RC, Tao W, Coleman HR, Thompson DJ,

Fullmer KR, et al. Ciliary neurotrophic factor (CNTF) for human retinal degeneration: Phase I trial of CNTF delivered by encapsu-

lated cell intraocular implants. Proc Natl Acad Sci USA 2006; 103: 3896-901.

[93] Spuch C, Antequera D, Portero A, Orive G, Hernandez RM, Molina JA, et al. The effect of encapsulated VEGF-secreting cells

on brain amyloid load and behavioural impairment in a mouse model of Alzheimer’s disease. Biomaterials 2010; 31: 5608-18.

[94] Day-Lollini PA, Stewart GR, Taylor MJ, Johnson RM, Chellman GJ. Hyperplastic changes within the leptomeninges of the rat and

monkey in response to chronic intracerebroventricular infusion of nerve growth factor. Exp Neurol 1997; 145: 24-37.

[95] Yamada K, Kinoshita A, Kohmura E, Sakaguchi T, Taguchi J, Kataoka K, et al. Basic fibroblast growth factor prevents thalamic

degeneration after cortical infarction. J Cereb Blood Flow Metab 1991; 11: 472-8.

[96] Orive G, Ali OA, Anitua E, Peraz JL, Emerich DF. Biomaterial-based Technologies for brain anti-cancer therapeutics and imaging.

Biochim Biophys Acta 2010; 1806: 96-107. [97] Bjerkvig, R. Alginate capsules for use in the treatment of brain

tumour. US20056926888 (2005). [98] Allard E, Passirani C, Benoit JP. Convention enhanced delivery of

nanocarriers for the treatment of brain tumours. Biomaterials 2009; 30: 2302-2318.

[99] Rzigalinski, B., Ariane, C. Anti-inflammatory, radioprotective and longevity enhancing capabilities of cerium oxide nanoparticles.

WO2007002662 (2007). [100] Rzigalinski, B., Cohen, C., Singh, N. Cerium oxide nanoparticles

for treatment and prevention of Alzheimer’s disease, Parkinson’s disease and disorders associated with free radical production and

/or mitochondrial dysfunction. WO2009052295 (2009). [101] Rzigalinski, B., Singh, N., Cohen, C. Cerium oxide nanoparticles

for treatment and prevention of Alzheimer’s disease, Parkinson’s disease and disorders associated with free radical production and

/or mitochondrial dysfunction. US2009092671 (2009). [102] Lautenschaeleger, H., Elias, I. New nanoparticles containing nico-

tine and/or cotinine useful e.g. for cigarette weaning and to treat e.g. attention-deficit hyperactivity disorder, Parkinson's disease,

Alzheimer's disease and Binswanger'. DE102007017298 (2007). [103] Legname, G., Krol, S., Costa de Sousa, M. Gold nanoparticles

coated with polyelectrolytes and use thereof as medicament for the treatment of neurodegenerative diseases caused by protein aggre-

gates. WO2010052665 (2010). [104] Mook, I.H., Han, S.H., Chang, Y.J. Method for diagnosing Alz-

heimer’s disease or dementia related neurological disease using gold nanoparticle. KR101003124 (2010).

[105] Corot, C. Use of metal nanoparticles in the diagnosis of Alz-heimer’s disease. US2010111876 (2010).

[106] Orive G, Hernandez RM, Gascon AR, Igartua M, Rojas A, Pedraz JL. Microencapsulation of an anti-VE-cadherin antibody secreting

1B5 hybridoma cells. Biotechnol Bioeng 2001; 76: 285-294. [107] Rodriguez, M., Miller, D.J., Pease, L.R. Human immunoglobulin

M antibodies. US20097473423 (2009). [108] Singh N, Pillay V, Choonata YE. Advances in the treatment of

Parkinson’s disease. Prog Neurobiol 2007; 81: 29-44. [109] LeWitt PA. Levodopa for the treatment of Parkinson’s disease. N

Engl J Med 2008; 359: 2468-2476. [110] De Giglio, Trapani A, Cafagna D, Sabbatini L, Cometa S. Dopa-

mine loaded chotosan nanoparticles: formulation and analytical characterization. Anal Bioanal Chem 2011; 400: 1997-2002.

[111] Tsai MJ, Huang YB, Wu PC, Fu YS, Kao YR, Fang JY, et al. Oral apomorphine delivery from solid lipid nanoparticles with different

monoesterate emusifiers: pharmacokinetic and behavioural evalua-tions. J Pharm Sci 2011; 100: 547-57.

[112] Volvert AA, Subramaniam V, Ivanov MR, Goodman AM, Haes AJ. Salt-mediated self assembly of thioctic acid on gold nanoparti-

cles. ACS Nano 2011; 5: 4570-80.

[113] Ivanov MR, Haes AJ. Nanomaterial surface chemistry design for

advancements in capillary electrophoresis modes. Analyst 2011; 136: 54-63.

[114] Ziady AG, Gedeon CR, Miller T, Quan W, Payne JM, et al. Trans-fection of airway epithelium by stable PEGylated poly-L-Lysine

DNA nanoparticles in vivo. Mol Ther 2003; 8: 936-47. [115] Kordower JH, Chu Y, Hauser RA, Freeman TB, Olanow CW.

Lewy body like pathology in long term embryonic nigral trans-plants in Parkinson’s disease. Nat Med 2008; 14: 504-6.

[116] Farjo R, Skaggs J, Quiambao AB, Cooper MJ, Naash MI. Efficient non viral ocular gene transfer with compacted DNA nanoparticles.

PLoS ONE 2006; 1:e38. [117] Yurek DM, Fletcher AM, Smith GM, Seroogy KB, Ziady AG,

Molter J, et al. Long-term transgene expression in the central nerv-ous system using DNA nanoparticles. Mol Ther 2009; 17; 641-50.

[118] Yurek, DM, Fletcher AM., Kowalczyk TH, Padegimas L, Cooper MJ. Compacted DNA nanoparticle gene transfer of GDNF to the

rat striatum enhances the survival of grafted fetal dopamine neu-rons. Cell Transplant 2009, 18: 1183-96.

[119] Huang R, Ke W, Liu Y, Wu D, Feng L, Jiang C, et al. Gene ther-apy using lactoferrin-modified nanoparticles in a rotenone-induced

chronic Parkinson model. J Neurol Sci 2010; 290: 123-30. [120] Wu S, Ma C, Li G, Mai M, Wu Y. Intrathecal implantation of mi-

croencapsulated PC12 cells reduces cold allodynia in a model of neuropathic pain. Artif Organs 2011; 35: 294-300.

[121] Roberts T, De Boni U, Sefton MV. Dopamine secretion by PC12 cells microencapsulated in a hydroxyethyl methacrylate-methyl

methacrylate copolymer. Biomaterials 1996; 17: 267-75. [122] Ballard C, Kahn Z, Corbett A. Treatment of dementia with lewy

bodies and parkinson’s dementia. Drugs Aging 2011; 28: 769-77. [123] Volpicelli-Daley LA, Luk KC, Patel TP, Tanik SA, Riddle DM, et

al. Exogenous alpha-synuclein fibrils induce Lewy body pathology leading to synaptic dysfunction and neuron death. Neuron 2011;

72: 57-71. [124] Lim Y, Kehm VM, Lee EB, Soper JH, Li C, Trojanowski JQ, et al.

Alpha synuclein suppression reverse synaptic and memory defects in a mouse model of dementia with Lewy bodies. J Neurosci 2011;

72: 57-71. [125] Fitzgerald P, Mandel A, Bolton AE, Sullivan AM, Nolan Y.

Treatment with phosphotidylglycerol-based nanoparticles prevents motor deficits induced by proteasome inhibition: Implications for

Parkinson's disease. Behav Brain Res 2008; 195: 271-4. [126] Milowska K, Malachowska M, Gabryelak T. PAMAM G4 den-

drimers affect the aggregation of alpha-synuclein. Int J Biol Mac-romol 2011; 48: 742-6.

[127] Knopman DS. Alzheimer’s disease and other dementias. In: Gold-man L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa:

Saunders Elsevier 2007: chapter 425. [128] Barmada SJ, Finkneiner S. Pathogenic TARDBP mutations in

amyotrophic lateral sclerosis and frontotemporal dementia: Dis-ease-associated pathways. Rev Neurosci 2010; 21: 251-72.

[129] Rohrer JD, Geser F, Zhou J, Gennatas ED, Sidhu M, Trojanowski JQ, et al. TDP-43 subtypes are associated with distinct atrophy pat-

terns in frontotemporal dementia. Neurology 2010; 75: 2204-11. [130] Klein, R., Henning, P., Wang, D., Dayton, R., Tatom, J., Orchard,

E. Assays of neurodegenerative disorders, including frontotemporal dementia and amyotrophic lateral sclerosis. US20110203007

(2011). [131] Enciu AM, Constantinescu SN, Popescu LM, Mures D, Popescu

BO. Neurobiology of vascular dementia. J Aging Res 2011; 401604: 1-11

[132] Cohen RA. Hypertension and cerebral blood flow: Implications for the development of vascular cognitive impairment in the elderly.

Stroke 2007; 38: 1715-7. [133] Mogi M, Horiuchi M. Neurovascular coupling in cognitive im-

pairment associated with diabetes mellitus. Circulation J 2011; 75: 1042-8.

[134] Ritz MF, Fluri F, Engelter ST, Schaeren-Wiemers N, Lyrer PA. Cortical and putamen age related changes in the microvessel den-

sity and astrocytes deficiency in spontaneously hypertensive and stroke-prone spontaneously hypertensive rats. Current Neurovascu-

lar Research 2009; 6: 279-87. [135] Sung, H.W., Liang, H., Tu, H. Nanoparticles for protein drug de-

livery. US20117863257 (2011).


[136] Li, Y., Gu, W., Chen, L. Huperzine, A and its derivates or salts

sustained release nanometer granule and preparing method thereof. CN101264058 (2010).

[137] Prusiner SB. Prions. Proc Natl Acad Sci 1998; 95: 13363-83 [138] Dormont D. Prion diseases: pathogenesis and public health con-

cerns. FEBS Let 2002; 592: 17-21. [139] Abid K, Soto C. Biomedicine and diseases: Review the intriguing

prion disorders. Cell. Mol Life Sci 2006; 63: 2342-51. [140] Hu W, Kieseier B, Frohman E, Eagar TN, Rosenberg RN, et al.

Prion proteins: Physiological functions and role in neurological disorders. J Neurol Sci 2008; 264: 1-8

[141] Tatzelt J, Schatzl HM. Molecular basis of cerebral neurodegenera-tion in prion disease. FEBS J 2007; 274: 606-11.

[142] Wadsworth JDF, Collinge J. Update on human prion disease. Bio-chim Biophys Acta 1772; 598-609.

[143] Taraboulos A, Jendroska K, Serban D, Yang SL, DeArmond SJ, Prusiner SB. Regional mapping of prion proteins in brain. Proc

Natl Acad Sci USA 1992; 89: 7620-4. [144] Aguzzi A, Glatzel M. Prion infections, blood and transfusions. Nat

Clin Pract Neurol 2006; 2:321-9. [145] Castilla J, Saa P, Soto C. Detection of prions in blood. Nat Med

2005; 11: 982-5. [146] Alvarez-Puebla RA, Agarwal A, Manna P, Khanal BP,

Aldeanueva-Potel P, Carbó-Argibay E, et al. Gold nanorods 3D-supercrystals as surface enhanced Raman scattering spectroscopy

substrates for the rapid detection of scrambled prions. Proc Natl Acad Sci USA 2011; 108: 8157-61.

[147] Xiao SJ, Hu PP, Wu XD, Chen LQ, Peng L, Ling J, et al. Sensitive

discrimination and detection of prion disease-associated isoform with a dual-aptamer strategy by developing a sandwich structure of

magnetic microparticles and quantum dots. Anal Chem 2010; 82: 9736-42.

[148] Zhang LY, Zheng HZ, Long YJ, Huang CZ, Hao JY, Zhou DB. CdTe quantum dots as a highly selective probe for prion protein de-

tection: Colorimetric qualitative, semi-quantitative and quantitative detection. Talanta 2011; 83: 1716-20.

[149] Miller MB, Supattapone S. Superparamagnetic nanoparticle capture of prions for amplification. J Virol 2011; 85: 2813-7.

[150] Calvo P, Gouritin B, Brigger I, Lasmezas C, Desyls JP, Williams A, et al. PEGylated polycyanoacrylates nanoparticles as vector for

drug delivery in prion diseases. J Neurosci Methods 2001; 111: 151-55.

[151] Legname, G.A., Krol, S., Costa de Sousa, M.F. Gold nanoparticles coated with polyelectrolytes and albumin. US20112622546 (2011).

[152] Cheon, J.W., Lee, J.H. Zinc containing magnetic nanoparticle based magnetic separation systems and magnetic sensors.

WO2010151085 (2010). [153] Deasi, N., Peykov, V., Soon-Shiong, P. Prion free nanoparticle

compositions and methods. WO2010121000 (2010). [154] Bergen JM, Park IK, Horner PJ, Pun SH. Nonviral approaches for

neuronal delivery of nucleic acids. Pharm res 2008; 25: 983-98. [155] Legname, G.A., Krol, S., Costa de Sousa, M.F. Gold nanoparticles

coated with polyelectrolytes and albumin. US2011262546 (2011)

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