VASCULAR ENDOTHELIUM & VASCULAR ENDOTHELIUM & ITS ITS FUNCTIONAL ASSESSMENT FUNCTIONAL ASSESSMENT Upa Kukongviriyapan Upa Kukongviriyapan Department of Physiology, Faculty of Medicine Department of Physiology, Faculty of Medicine Khon Kaen University, Thailand. Khon Kaen University, Thailand. B.Sc. Experimental Pathology B.Sc. Experimental Pathology Queen Mary’s School of Medicine and Queen Mary’s School of Medicine and Dentistry Dentistry The Royal London Hospital The Royal London Hospital October 12, 2005 October 12, 2005
31
Embed
VASCULAR ENDOTHELIUM & ITS FUNCTIONAL ASSESSMENT Upa Kukongviriyapan Department of Physiology, Faculty of Medicine Khon Kaen University, Thailand. B.Sc.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
B.Sc. Experimental PathologyB.Sc. Experimental PathologyQueen Mary’s School of Medicine and Queen Mary’s School of Medicine and
DentistryDentistryThe Royal London HospitalThe Royal London Hospital
October 12, 2005October 12, 2005
Topic ContentsTopic Contents
• Structure and functions of Structure and functions of vascular endothelial cell.vascular endothelial cell.
• The endothelial dysfunction. The endothelial dysfunction. • The oxidant- stress induced The oxidant- stress induced
endothelial dysfunction.endothelial dysfunction.• How to assess endothelial How to assess endothelial
functions.functions.• SummarySummary
The Normal Vascular EndotheliumThe Normal Vascular Endothelium
• Historically viewed as a passiveHistorically viewed as a passive vascular liningvascular lining..
Vascular Endothelium Vascular Endothelium
• Many important roles to maintain vascular Many important roles to maintain vascular homeostasis:homeostasis:– Vascular tone regulationVascular tone regulation– VSMC proliferationVSMC proliferation– Inflammatory responsesInflammatory responses– HaemostasisHaemostasis
• It produces and releases vasoactive, thromb It produces and releases vasoactive, thromb oregulatory and growth factor substances. oregulatory and growth factor substances.
Tousoulis, et al., Heart 2005; 91Tousoulis, et al., Heart 2005; 91: 353-358.: 353-358.
) • Noninvasive, simple, reproducible and less Noninvasive, simple, reproducible and less
observer dependent, need further validationobserver dependent, need further validation..
• The strain-gauge is attached to the upper forearm, and connected to plethysmographic device.
..• FBF is measured by temporarily occluding the FBF is measured by temporarily occluding the
venous return (by a cuff inflated to 40 mmHg) and venous return (by a cuff inflated to 40 mmHg) and measured the slight swelling of the distal portion measured the slight swelling of the distal portion of the limb due to continued arterial inflow.of the limb due to continued arterial inflow.
• The initial rate of The initial rate of swelling represents the swelling represents the arterial inflow.arterial inflow.
• The technique evaluates The technique evaluates the percentage change the percentage change of flow from baseline to of flow from baseline to the maximum flow the maximum flow during reactive during reactive hyperaemia following a hyperaemia following a five minute ischaemia of five minute ischaemia of the forearm.the forearm.
Forearm blood flow(Strain-gauge plethysmogra phy)
Tousoulis D, et al., Heart 2005: 91: 553-558.Tousoulis D, et al., Heart 2005: 91: 553-558.
Sample window• The FBF is estimated by the gradient of the tangent to the curve
during the first cardiac cycles.• R esult of forearm flow is expressed as ml/100 ml tiss/min or the percent changes in flow.
Timetable of FMD & FBF
Tousoulis D, et al., Heart 2005; 91Tousoulis D, et al., Heart 2005; 91: 353-358.: 353-358.
Application in clinical trials
• Study design: A - cute or long term intervention tr
ials.
• Sample size: A crossover or - a parallel group de
sign study.
• Methodology: S elect most reproducible results.
• E valuating precision of the technique.
• I ndividual training in the principles and te
chnical
aspect of Doppler ultrasonography and Strain-
gauge
plethysmography.
SUMMARYSUMMARY
• Endothelial functional testing can be used as an indicator for vascular damage or vascular disease and also other diseases relating to oxidative stress conditions.
• Reversal of endothelial dysfunction protects against progression of vascular disease.
• Proposed new tests for evaluating endothelial function should be developed with optimal characteristics; – Cost-effective, reproducible and
standardization.– Ability to predict risk and relationship to
established tests of risk.– Useful as a screen for drug development.– Can identify individual patients.– Can predict a reduction in the risk of clinical
events.
SUMMARYSUMMARY
QUESTIONSQUESTIONS
• What are the main functions of the vascular What are the main functions of the vascular
endothelial cell?endothelial cell?
• What is the endothelial dysfunction? How can it What is the endothelial dysfunction? How can it
lead to the cardiovascular disease?lead to the cardiovascular disease?
• How can we evaluate the endothelial How can we evaluate the endothelial
functions?functions?
• What are the key points for evaluating the What are the key points for evaluating the
endothelial dysfunction?endothelial dysfunction?
The End For NowThe End For NowBut there is much more to But there is much more to