Atherosclerosis Flashcards
Arteriosclerosis
Arteriolosclerosis
Stiffening of the blood vessels with loss of compliance
◉Arteriosclerosis= large and middle arteries
Hyaline arteriolosclerosis and hyperplastic arteriolosclerosis
◉Arteriolosclerosis= small arteries and arterioles
due to the process of atherosclerosis. growing fatty deposits (atheroma) but also lose compliance due to calcification and an increase in fibrous tissue in the vessel wall.
Atherosclerosis
A disease of large and medium-sized arteries characterized by
◉endothelial dysfunction,
◉vascular inflammation
◉accumulation of lipids, cholesterol, calcium and cellular debris
within the intima of the vessel wall.
Endothelial Dysfunction
inflammatory activationof vascular cells in diseased vessels
Response-to-injury hypothesis
This model views atherosclerosis as a chronic inflammatory response of the arterial wall to endothelial injury
Causes of endothelial injury
◉Physical injury or stress as a result of direct trauma or hypertension
◉Turbulent blood flow
◉Circulation of reactive oxygen species (free radicals), e.g., from smoking or air pollutants
◉Hyperlipidaemia (high blood concentrations of LDL or VLDL)
◉Chronically elevated blood glucose levels
◉Homocysteinaemia, an inherited metabolic defect that leads to very high levels of the homocysteine, a metabolite of methionine; high concentrations are toxic to the endothelium
What happens during inflammation in Endothelial Cells?
◉Disrupted permeability barrier
Increased prod of inflammatory cytokines > permeability
◉>prod of leukocyte adhesion molecules > immune cell recruitment
◉
Types of inflammatory cytokines
IL-1, IL-6, IL-8,TNF a
Types of leukocyte adhesion molecules
V-CAM, I-CAM,E-Selectin, P-Selectin
What happens during inflammation in Smooth Muscle Cells?
◉> prod of inflammatory cytokines
◉> extracellular matrix synthesis
◉> inc migration and proliferation into sub-intima
Stages of Plaque Development
Fatty Streak
Plaque development
Plaque Disruption/Rupture
Fatty Streak Development
LDL enter permeable endothelium - accumulation in tunica intima and bind to proteoglycans in extracellular matrix - Plasma LDL is oxidised and readily taken up by scavenger receptors on macrophages - transform to lipid laden foam cell. Oxidised LDL release cytokines, GF, - Endothelial cells release chemokines and macrophage - > recruitment. Further inducing of endothelial dysfunction
Plaque Development
Cytokines and GF stimulate SMC migration from media to intima and proliferation of SMC and ECM prod. - inflammation reinforced and atheroma formed (fibrofatty lesion) - calcification and continuous fibrosis - apoptosis of SMC > acellular fibrous capsule
RIsk factors for atherosclerosis
Cardiovascular disease risks ◉Non modifiable - Age Gender Ethnicity Genetics ◉Modifiable High BP Smoking DM Physical inactivity Obesity High blood cholesterol/ Dyslipidaemia/Hyperlipidaemia
Chlamydia pneumoniae infection
Acute Coronary Syndrome
Life-threatening conditions that encompass a continuum ranging fromunstable angina (UA)pectoris to the development of a large acutemyocardial infarction (MI),
MI symptoms
Chest pain - metabolic products activate pain receptors Tachycardia Dyspnoea Diaphoresis - >symp tone Nause/Vomiting >parasymp tone
Cardiac markers
Cardiac Troponin I and T - 3-4hrs, remains 10-14dyas
CK-MB - Heart and skeletal muscle -3-6hrs(pk14hrs) ,remains 48-72hrs