BIOMED SCIE Lecture 10

• Stents


  Treatments/Medical interventions
• Coronary artery bypass surgery


  Treatments/Medical interventions

  
• Local hormones


  Intracellular hormone-like substances, usually made and used locally within cells, not transported in the bloodstream to other cells for action
• Local hormone synthesis


  1. Essential fatty acids converted to arachidonic acid in membranes

  2. Arachidonic acid released from membrane and converted into local hormones such as prostaglandins, thromboxanes and leukotrienes

  
• Local hormones


  • Regulate immunity, platelet aggregation (ie blood clotting), vascular dilation, inflammation
• Aspirin


  • Inhibits the breakdown of arachidonic acid from membranes to produce prostaglandins and thromboxanes
  • Inhibits thromboxane that helps platelets clot, so anti-platelet/anti-clotting
  • Derivative of salicylate from bark of the willow tree
  • First made in 1853 and sold by Bayer pharmaceuticals
  • In patients at risk of MI/stroke aspirin is used long-term, at low doses
  • Side-effects (enteric coating)
  • One of the most widely used drugs in the world, with an estimated 40,000 tonnes of it consumed globally each year

  
• Angina


  • Lack of blood supply to part of the heart
  • Results in "Cramp" in your heart
  • Lack of oxygen = pain
• Nitrates


  • Acute vasodilators - open up coronary arteries quickly
  • Nitroglycerin provides symptomatic relief
  • Converted to NO which is a potent vasodilator – expands the blood vessels
  • Can develop drug tolerance - drug free period

  
• Beta-blockers


  • Beta-adrenergic receptor antagonists (inhibit effects of adrenaline)
  • Decrease heart rate and heart O2 demand
• Blood pressure


  • Measured from an artery in the arm at the same height as the heart
  • For a healthy 20-year-old at rest is 120mm Hg at systole and 70mmHg at diastole

  
• Hypertension


  • Elevated "blood pressure", promotes endothelial dysfunction/damage
  • Tension/Pressure exerted by blood on the arteries
  • Activation of epithelial cells, expression of adhesion molecules, monocyte migration

  
• Vasodilators


  Alleviate smooth muscle contraction in artery wall
• Diuretics


  Reduce blood pressure, by reducing blood volume
• Statins


  • Inhibitors of HMG-CoA reductase, an enzyme used to make cholesterol in liver
  • Reduced blood cholesterol (including LDL)
  • Reduce risk of heart attack
  • Primary preventative intervention for people with risk factors for coronary heart disease
  • Secondary intervention for those with pre-existing heart disease or associated complications (eg previous heart attack, angina, stroke…)
  • eg Atorvastatin (Pfizer) – best selling medication in history
• Leading global risks for mortality


  • High blood pressure
  • Tobacco use
  • High blood glucose
  • Physical inactivity
  • Overweight and obesity
• 86% of deaths and 77% of disease burden in Ireland are now caused by lifestyle-related chronic diseases: certain forms of cancer, cardiovascular disease, stroke, chronic respiratory diseases and type II diabetes. Lifestyle effects begin in childhood.
• These conditions represent the significant majority of GP consultations and hospital admissions.
• 75% of healthcare expenditure in Ireland is allocated to the management of chronic diseases
• 80% of premature heart disease and stroke is preventable.

  
• Non-communicable diseases


  • Including diabetes, cancer and ischaemic heart disease account for 60% of all deaths worldwide
  • The prevalence of diseases such as type II diabetes has reached epidemic proportions
• Estimated 285 million people (6.4% of the world's adult population), lived with diabetes in 2010. Expected to grow to 438 million (7.8% of the adult population) by 2030.
• ~250,000 people diagnosed with diabetes in Ireland. It is estimated that this number would double if all cases were diagnosed.
• Type II diabetes was considered to be "adult-onset" now children and teenagers are being diagnosed
• 80% of type II diabetes is preventable by changing diet, increasing physical activity and improving the living environment.
• Mediterranean diet


  • Eating a generous amount of fruits and vegetables (up to 9 servings)
  • Consuming 'healthy fats' such as olive oil
  • Bread but wholegrain and no saturated/trans fats
  • Eating small portions of nuts (walnuts: Omega-3)
  • Consuming very little red meat
  • Eating fish on a regular basis (Omega-3)
  • Reduce portion size of high-fat and -sugar food
• French Paradox


  • Relatively high amounts of saturated fat in their diet (no trans-fats)
  • Despite this fat intake, the French have lower rates of heart disease. Attributed to the possible benefits of drinking red wine in moderation
  • Possible cardioprotective constituents of moderate red wine consumption: Antioxidants present in red wine - polyphenols, resveratrol (in grapeskin)
  • These compounds are proposed to act by inhibiting low-density lipoprotein oxidation and thrombosis
• What's the solution to reducing incidence of Cardiovascular Disease in Ireland?


  • Consume a diet high in fruits, vegetables, nuts and whole grains, and low in refined grains
  • Avoid trans fats - hard margarines, any product containing "hydrogenated vegetable oil" or partially hydrogenated vegetable oil"
  • Avoid excess saturated fats - animal fat and dairy fat
  • Increase consumption of omega-3 fatty acids from fish or plant sources
  • Avoid excessively salty or sugary foods
  • Get at least 30 minutes of regular physical activity on most days
  • Avoid smoking
  • Maintain a healthy weight
• Educating our population would go along way to reducing our huge health care burden!
• Anti-inflammatory approach:Inflammation plays a role in atherosclerosis and thrombus formation• Aspirin inhibits inflammation and reduces the risk of heart attacks and stroke
• Hypertension, or high blood pressure, promotes atherosclerosis and increases the risk of heart attack and stroke• Hypertension can be reduced by dietary changes, exercise and/or medication (eg vasodilators and diuretics)