Chronic Diseases & Nutrition Cardiovascular Diseases PDF

Chronic Diseases & Nutrition Cardiovascular Diseases and Hypertension Faculty of Science | Department of Biochemistry Faculty of Science | Department of Biochemistry Cardiovascular Diseases (CVD) At the root of most forms of CVD is atherosclerosis:...

Chronic Diseases & Nutrition Cardiovascular Diseases and Hypertension Faculty of Science | Department of Biochemistry Faculty of Science | Department of Biochemistry Cardiovascular Diseases (CVD) At the root of most forms of CVD is atherosclerosis: Hardening of the arteries caused by plaques High saturated fat diet contributes to the build up of plaque Atherosclerosis is also the body’s inflammatory response to tissue damage A long‐standing myth is that CVD is a men’s disease; in fact, more women than men die of CVD in all of its forms each year. Men have more heart attacks than women do, but women still have them in large numbers. Faculty of Science | Department of Biochemistry How Atherosclerosis Develops Damage begins with: High LDL cholesterol Hypertension Toxins from cigarette smoking Elevated homocysteine levels in blood Viral or bacterial infections Such damage produces an inflammatory response that provokes the immune system to send white blood cells (macrophages) to the site to try to repair the damage. Soon particles of LDL cholesterol become trapped in the blood vessel walls and become oxidized by free radicals produced during inflammatory responses. As the macrophages become engorged with oxidized LDL, they become known as foam cells. Faculty of Science | Department of Biochemistry Image Source: http://www.nhlbi.nih.gov/health/health‐topics/topics/cad/ Arteries hardened and narrowed by plaques cannot expand, so the blood pressure rises. The increased pressure damages the artery walls further and strains the heart. Faculty of Science | Department of Biochemistry Progression of Atherosclerosis a. Initial lesion develops in the vessel and fatty streak begins to form b. Lesion progresses accumulating inflammatory cells, etc c. Lesion is vulnerable to a rupture d. Advanced obstruction or occlusion Image from: Rader & Daugherty (2008) Nature 451, 904‐913 doi:10.1038/nature06796 Faculty of Science | Department of Biochemistry Blood clots Thrombus: Stationary clot Thrombosis: Large clot that closes off a blood vessel Embolus: A clot that breaks loose Embolism: A clot that becomes stuck A clot may: Lodge in an artery of the heart, causing sudden death of part of the heart muscle: a heart attack. Lodge in an artery of the brain, killing a portion of brain tissue: a stroke. Faculty of Science | Department of Biochemistry Abdominal aorta Aortic Aneurysm: forms because of pressure build up and damage to the artery wall Faculty of Science | Department of Biochemistry Sanz & Fayad. Imaging of atherosclerotic cardiovascular disease. Nature 451, 953‐957(2008) doi:10.1038/nature06803 Faculty of Science | Department of Biochemistry Patterns of vascular ageing in men and women. ‘+’ symbols represent the presence of estrogen receptors in the arterial vasculature (including endothelium, smooth muscle cells and extracellular matrix). Coronary arteries with 50% to 75% loss of inner diameter Angina with exercise (ischemia) 90% = ischemia and pain at rest Acute Treatment: angioplasty/stent Planned Treatment: Bypass surgery or stent Allison A Merz, and Susan Cheng Heart 2016;102:825-831 Faculty of Science | Department of Biochemistry Faculty of Science | Department of Biochemistry The Seven Countries Study Ancel Keys suggested 2/3 variation in serum cholesterol were attributable to saturated fatty acids Faculty of Science | Department of Biochemistry In men, aging becomes a significant risk factor for heart disease at age 45 years or older. In women, the risk increases after age 55 up to age 45, a woman’s risk of developing heart disease is lower than a man’s of the same age, but for women past menopause, rates of heart disease increase two to three times over premenopause rates Early heart disease in immediate family members (siblings or parents) is a major risk factor for developing it. Faculty of Science | Department of Biochemistry LDL carry cholesterol to the cells, including the cells that line the arteries, where it can build up as part of the plaques of atherosclerosis. HDL carry cholesterol away from the cells to the liver for other uses or disposal. Elevated HDL indicates a reduced risk of atherosclerosis and heart attack, with growing evidence that it may prevent stroke as well. Faculty of Science | Department of Biochemistry Adults Standards for Blood Lipids, Body Mass Index (BMI), and Blood Pressure Faculty of Science | Department of Biochemistry Framingham Risk Score Score = Values for Age + HDL + BP +Total Chol Dr. Harding’s Score = 5 0 1 1 =7 Faculty of Science | Department of Biochemistry 10 yr Risk 20 score: 70 year old male Up to Low HDL levels 27.5% (F) Treated HT (still mildly HT) >30% (M) Mod total cholesterol levels Faculty of Science | Department of Biochemistry Risk Factors for CVD Hypertension Worsens CVD Accelerates plaque formation Diabetes Independent risk factor for CVD Obesity and physical inactivity Central obesity and physical inactivity elevate LDL cholesterol, lower HDL cholesterol Faculty of Science | Department of Biochemistry Risk Factors for CVD Smoking Directly damages heart with toxins and increases blood pressure Makes blood clots likely to develop When people quit smoking, their risk of heart disease begins to drop within a few months; a year later, their risk has dropped by half, and after 15 years of staying smoke‐free, their risks equal those of lifetime nonsmokers Atherogenic diet Diet high in saturated fat, trans fat, and cholesterol Faculty of Science | Department of Biochemistry Risk Factors for CVD Metabolic syndrome A characteristic cluster of CVD risk factors Features of metabolic syndrome: Central obesity Abnormal blood lipids: low HDL and high triglycerides Elevated blood pressure Elevated fasting blood glucose or insulin Resistance People with elevated triglycerides should limit simple sugars and highly refined starchy foods, which often cause triglycerides to rise Faculty of Science | Department of Biochemistry Atherogenic Lipoprotein Phenotype Raised VLDL Predominance of small dense LDL Low HDL Clinically can be identified by: Elevated plasma TAG >1.7 mmol/L and Low HDL‐cholesterol ;