TISSUE BANKING: Standards, Procedures, and Applications.

TISSUE BANKING:

Standards, Procedures, and Applications

Tissue Banking: History

Prior to 1980’s, very few active tissue banks existed.– Apart from corneas, storage of human tissue was not common

– Tissues for transplantation were scarce

– No professional standards and government control meant that effectiveness were uncertain

Tissue Banking: History

Introduction of Immunosuppressant drugs in the 1980’s led to:– Successful organ transplants

– Public support and effective organ donation programs

– Paved the way for use of cadaver tissue donations.

– Increased availability of tissue allografts

– Tissue banks combined with organ and tissue procurement agencies (COPA, UNOS)

Tissue Banking: History

Early Tissue Banking– Originally managed by surgeons, had many quality control

problems

– Poor stored tissue quality

– Very little disease testing

– Poor tracking of tissue sources

TMS Involvement Improved Quality of Work– ABO, Rh typing

– Improvements in source tracking

– Better quality storage equipment

– Reputation of blood banking improved community relations and donor pool

Tissue Banking: History

Government Regulations of Tissue Banks– In 1993, an Interim Rule was implemented by the FDA

– Allowed FDA inspection of tissue banks, ability to recall and destroy unsuitable tissues

– FDA requirements focused on assuring safety of tissue for transplant, accuracy of medical history and records, proper processing and storage of tissue.

Tissue Banking: History

Increasing Surgical Demands For Allografts– Demand for bone in hip replacements, femoral head allografts,

mending acetabular and femoral defects.

– Demands for cadaver skin in burn patients exceeds supply in US, skin imported from Europe to meet demands.

Tissue Banking: Applications

Apart From Blood, Banked Tissues Include:– Bone, frozen, freeze-dried, and de-mineralized

– Corneas

– Heart valves

– Tendons

– Skin

– Haematopoetic Tissues, bone marrow and cord blood

– Dura mater, ear ossicles, and cartilage, to a lesser degree

Tissue Banking: Applications

Growth In Tissue Banking– 300,000 bone allografts made annually

– 40,000 corneas transplanted annually

– 20,000 cadaveric organs transplanted annually

– 50,000-100,000 vials of powdered bone in dental practice annually

Tissue Banking: Applications

Common Clinical Uses For Banked Tissue– Bone allografts used in spinal fusion surgery

– Tendon allografts for knee ligament replacement

– Heart valves for treatment of congenital heart defect in children

– Viable and non-viable skin dressing for burn patients

– Powdered bone used in dental repairs

– Hematopoetic stem cells and marrow used to replace bone marrow

Tissue Banking: Standards

Process required for Safe Tissue Transplantation– Donor’s medical and social history – next of kin, physicians,

hospital records

– Donor blood microbiological testing • Serologic

• PCR

– Physical examination of cadavers• tattoos

• needle marks

• other indications of risky lifestyle

– Review of autopsy exam results.

– Aseptic tissue retrieval.

Tissue Banking: Standards

Requirements For Donor Selection– National Blood Service require:

• HIV 1 & 2

• Hepatitis B & C

• serologic testing for syphilis

– Non-mandatory tests: CMV, Hepatitis G, and HTLV I & II

Various Testing Methods Used to Detect Viruses– Hepatitis B testing for surface antigens

– HIV and Hepatitis C detect presence of antibodies to virus

– ELISA used for HIV, may not detect donors in seroconversion

– PCR used to detect HIV viral nucleotide without depending on antibody response – more sensitive and specific

Procedures: ABO, Rh

ABO & Rh Typing– Major ABO mismatching can cause rapid graft rejection due to

damage by ABO antibodies, causing endothelial damage and thrombosis

– ABO matching is important to the success of all vascular tissue grafts – liver, kidneys, heart, lungs, and pancreas

ABO/Rh Typing Not Needed For Non-Vascular Tissue Grafts– Fascia

– Bone

– Heart Valves

– Skin

– Corneas

Procedures: HLA

HLA A, B, and Dr Loci are Matched For:– Kidneys and other soft organs when time permits

– Bone marrow

– Peripheral blood stem cells

– Second cornea grafts

HLA Matching Not Needed For Non-Viable Tissue– Bone

– Tendon

– Fascia

– Cartilage

– Epidermal Dressing

Procedures: Bone Collection

Collection Procedures– Fresh, autologous bone taken from illiac crest, reduces risk of

disease transmission

– Allograft bone also collected when conditions make autologous collection in impractical

– Can be frozen or freeze-dried, and stored at room temperature for five years

– Freeze dried bone is processed to remove marrow and blood, treated with alcohol, and irradiated, resulting in decreased risk of disease transmission

– Demineralizing bone makes proteins and growth factors readily available, promoting healing

Procedures: Skin Collection

Collection Procedures– Allograft skin used as dressing in deep burn patients

– Layers of skin 0.015 inch thick are removed

– Skin can be stored at 2-8 OC for up to 14 days, in a nutrient and antibiotic broth media

– Skin frozen and stored in liquid nitrogen freezer, or at –70 OC.

– Tissue stored using Dimethylsulfoxide, 15% Glycerol, or Phosphate Buffered Saline and another Cryoprotective Agent

– Thawing depends on freezing media used, some have cytotoxic effects at higher temperatures

Procedures: Skin Collection

Many Factors Affect Quality Of Skin– Delay in post-mortem collection reduces viability of tissue

– Autolytic and enzymatic degradation of tissue allows for enhancement of bacterial load

Secondary Concern Is Surface Contamination– Skin primarily collected in mortuary or funeral home.

Proper Aseptic Retrieval– Use of sterile drapes

– Decontamination of Skin

– Operating room techniques

– Use of sterile collection containers and instruments

Procedures: Skin Collection

Normal Skin carries both residual and transient normal flora– Normal flora reduced by transport at low temperatures in a sealed

container

– Normally placed in an antibiotic transport solution

– Transport solution similar to medium used to grow tissue cultures, helps maintain viability of graft

Procedures: Heart Valve Collection

Collection Procedures– Allografts do not require anticoagulation therapy like mechanical

grafts.

– Whole Heart aseptically collected in Operating Room or at autopsy.

– Aortic and pulmonary valves removed.

– Placed in DMSO, frozen in liquid nitrogen for storage

Procedures: Infection Control

Diseases Transmitted By Transplants:– HIV transmitted by bone and solid organ transplants

– Hepatitis transmitted by bone, bone marrow, and other organs

– Tuberculosis transmitted by bone and heart valves

– Prion diseases transmitted by corneas and dura mater

– Rabies has been transmitted by corneas

Incidence of Fungal and Bacterial Diseases– Occasionally of donor origin

– More commonly, acquired during tissue procurement, processing, or storage

Procedures: Infection Control

Sterilization of Banked Tissues Antimicrobial mixtures used must be effective against bacterial and

fungal contamination Ohio Valley Tissue and Skin Center – 0.4 mM L-glutamine, 100 units

penicillin, 100 g streptomycin, 200 g kanamycin, 8 mg gentamycin, and 100 g nystatin.

“Reina Sofia” Cordoba Spain – 50 g/ml tobramycin, 50 g/ml co-trimoxazole, 50 g/ml vancomycin, 50 g/ml amphotericin B

In clinical trials, both mixtures were 100% effective against normal flora gram-positive bacteria and had varying degrees of effectiveness against gram-negative and drug resistant gram-positive bacteria.

Against Candida sp., the Reina Sofia mixture was 100% effective, while the OVTSC mixture was shown to be ineffective on all trials.

Procedures: UNC Hospitals

Frozen Skin at UNC:– UNC Hospitals use tissue banked by OVTSC for skin allograft

– Tissues ordered and distributed by the Transfusion Medicine Services

– Tissue stored in -70 Degree Celsius Freezer

– Collected in 2x8 and 3x8 strips, ordered by square foot

ABO, Rh, HLA at UNC– UNC requires ABO/Rh type match on all tissues and organs

– HLA match done pre-transplant on kidneys only

– HLA match done post-transplant on heart, liver, lungs, and other organs, due to need for rapid transplant of these organs