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ENDOTHELIAL DYSFUNCTION - ED A Marker of Cardio Vascular Disease. Dr.R.V.S.N. Sarma., M.D., M.Sc., (Canada) Consultant Physician and Chest Specialist. Visit us at : www.drsarma.in. The Endothelium. Tunica intima. LUMEN. Tunica adventitia. Tunica media. LUMEN.
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ENDOTHELIAL DYSFUNCTION - EDA Marker of Cardio Vascular Disease Dr.R.V.S.N. Sarma., M.D., M.Sc., (Canada) Consultant Physician and Chest Specialist Visit us at : www.drsarma.in
Tunica intima LUMEN Tunica adventitia Tunica media
LUMEN Can you see the endothelium? What type of tissue is it? Why?
Vasoconstriction and dilatation Normal Vasoconstriction Vasodilatation
Vasoconstriction and dilatation ↓Resistance to flow ↑ Resistance to flow Vasodilatation Vasoconstriction
Endothelial Apoptosis Apoptosed Normal
The Vascular Endothelium • The inner lining of our bloods vessels is the Endothelium • It plays a central role in regulating the vasomotror tone & • Local homeostasis & control of the coagulation process • Endothelial cells have ‘Sensors’ and release ‘Mediators’ • ‘Mediators’ are the functional molecules on the cell surface
Oxidative stress and Endothelial dysfunction • Oxidative Stress leads to ED • Endothelial dysfunction is mainly due to reduced bioavailability and bioactivity of Nitric Oxide (NO) • It is also a physiological process • Takes place gradually by age and menopause.
The Effects of ED • Oxidant stress and Endothelial dysfunction are major factors for atherosclerosis – the common pathway– • for most of the cardiovascular risk factors including Hypertension, DM, Dyslipidemia and Smoking. • Both endothelial dysfunction and oxidant stress result in clinical conditions - Heart failure, IHD and MI
Vascular Endothelial Mediators Include the following • Nitric oxide (NO) • Cycloxygenase (CxO) • Endothelin-1 (ET-1) • Endothelium Depolarisation Factor (EDF) • And many others - thus • It is the largest endocrine gland
Nitric Oxide (NO) • Half-life of NO, is affected by its chemical reaction and inactivation by superoxide anion • NO is the most abundant free-radical in the body • It is the only biological molecule in high concentrations to out-compete superoxide dismutase for superoxide • NO has an anti-thrombogenic & anti-atherogenic role
Protective actions of NO Endothelial NO has the following actions • Smooth muscle relaxation and vasodilatation • Essential for regulation of blood pressure • Reduces proliferation of vascular smooth muscle • Protects blood vessel intima from injurious consequences of platelet aggregation
ED and NO ↓ NO deficiency in the vessel wall promotes • Inflammation • Oxidation of lipoproteins • Smooth muscle proliferation • Accumulation of lipid rich material • Platelet activation and thrombus formation Finally results in atherosclerosis.
Genes Coronary Risk Factors Endothelial Dysfunction NO ↑ Inflammation ↑ Thrombosis Coronary Heart Disease The Essential Components The Universal Damage
Regulatory Functions of the EndotheliumNormal Dysfunction Vasodilation Vasoconstriction NO, PGI2, EDHF, BK, C-NP ROS, ET-1, TxA2, A-II, PGH2 Thrombolysis Thrombosis tPA, Protein C, TF-I, vWF PAI-1, TF-α, Tx-A2 Platelet Disaggregation NO, PGI2 Adhesion Molecules CAMs, P,E Selectins Antiproliferation NO, PGI2, TGF-, Hep Growth Factors ET-1, A-II, PDGF, ILGF, ILs Inflammation ROS, NF-B Lipolysis LPL Vogel R
Oxidative Stress: Endothelial Dysfunction and CAD/Renal Risk Factors Homocysteine Estrogen deficiency Smoking LDL Diabetes Hypertension O2Endothelial Cells and H2O2 Vascular Smooth Muscle Endothelial Dysfunction Lipid deposition Thrombosis Apoptosis VSMC growth Leukocyte adhesion Vasoconstriction
Coronary Arteries Epicardial Artery Diameter with ACh CBF with ACh Epicardial Artery Diameter with Adenosine Forearm Brachial Artery Diameter with Arterial Occlusion FMD Forearm Blood Flow with ACh Clinical Methods for Assessing Endothelium - Dependent Dilation
Comparison of Brachial and Coronary Flow-Mediated Vasodilation
CVE’s over 7.7 Years in 147 Subjects with CAD According to Coronary Artery Responses to Ach, Cold Pressor, and FMD CVE’s
CVE’s over 4 Years in 176 Subjects without CAD as per CVR and CA Diameters Changes with ACh
Effect of ACh-Induced Forearm Vasodilation on CVE’s (%) in 225 Never Treated HTN cases
CVE’s According to FBF Responses to ACh and I.V. Vitamin C in 281 Subjects with CHD ACh-induced FBF Responses Vitamin C Responses
Brachial Artery Flow-Mediated VasodilationBaseline5 MinutesPost-OcclusionBlood Pressure Cuff Occlusion – 1 Minute Release 3.6 mm 3.1 mm
CHD Events over 5 Years in 76 CAD Patients According to Brachial Artery FMD
5-Year Outcome in 350 Postmenopausal Hypertensive Women with controlledBP (<140/90) Change in BAFMD
What is the Rx. for Endothelial Dysfunction? • Control of all the known CV risk factors • Main focus on the big six – DM, HTN, Lipids, Obesity, Smoking, Sedentary life style • Diet and physical activity are vital in Rx of ED • Statins are the first line treatment for ED • Glitazones have proven value to improve ED • Insulin and Rx. Insulin resistance improves ED