Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
24 Cards in this Set
- Front
- Back
What are the major families of lipoproteins?
|
-Chylomicrons
-VLDL -IDL -LDL -HDL |
|
Describe chylomicrons
|
-Originate in the intesting from exogenous (dietary) fat and are componsed primarily of triglycerides
-Serve to transport dietary fat from the intestine to sites of utilization and storage in the body -Usually rapidly shorn of much of their triglyceride through intravascular lipolysis -Chylomicron remnants are removed by the liver -Absent from plasma after 12-14 hours of fasting |
|
Describe VLDL
|
-Originate in the liver and small intestine
-Composed primarily of triglycerides of endogenous origin -Major function is triglyceride transport -Cholesterol:triglyceride ratio = 1:5 -15-25g of VLDL triglycerized released into bloodstream daily -VLDL undergoes rapid lipolysis to a IDL (30% cholesterol, 40% triglyceride) and then to LDL |
|
Describe LDL
|
-Major product of intravascular metabolism of VLDL
-50% cholesterol by weight -Removed from blood stream by specific LDL receptors on hepatic and peripheral cells -Elevation of LDL causes increased risk of coronary heart disease (CHD) |
|
Describe HDL
|
-Arises from liver and intestin
-Accepts cholesterol and other lipid nad protein fragments from VLDL and chylomicrons during intravascular lipolysis -Also transports cholesterol from peripheral tissue to the liver (reverse cholesterol transport) -Involves ABC-A1 and ABC-G1 transporters in peripheral tissues and scavenger receptor B1 (SR-B1) in the liver -HDL level inversely related to CHD |
|
What is the major carrier of cholesterol in the blood stream?
|
LDL, transporting 60-75% of the total plasma cholesterol
HDL accounts for less than 25% of the total plasma cholesterol |
|
Describe HDL levels between males nad females
|
Even in both sexes until pubescence when HDL concentrations in males falls ~20%
|
|
What determines HDL and LDL levels?
|
-Genetics and environment
-Strongest environmental factor is diet -Diet with high saturated fat and cholesterol cause high LDL -Higher HDL levels associated with moderate alcohol intake, exercise, and body leanness -Cigarette smoking, sedentary behaviour, insulinopenic diabetes, and obesity can lower HDL levels -Blacks have higher HDL levels than white |
|
Describe Lp(a)
|
-Cholesterol-rich lipoprotein
-Contains apoB-100 covalently linked to a protein with homology to plasminogen -Plasma levels of Lp(a) associated with prevalent of CHD -Not modified by dietary maneuvers or by most lipid-altering mediactions -Levels fall in response to treatment with nicotinic acid or estrogens |
|
How does Lp(a) predispose to CHD
|
-Delivering cholesterol to the vessel wall
-Interfering with thrombolytic events -Inhibiting expression of tissue factor -Carrying pro-inflammatory oxidized phospholipids |
|
What are the categories of LDL levels?
|
-Optimal (<100 mg/dl)
-Near optimal (100-130 mg/dl) -Borderline high (130-159 mg/dl) -High (160-189 mg/dl) -Very high (>190 mg/dl) |
|
What are the categories of HDL levels?
|
-Low (<40 mg/dl)
-Normal (40-59 mg/dl) -High (>60 mg/dl) |
|
What are the three risk categories of LDL levels?
|
-CHD/10-yr CHD risk >20% (LDL goal <100 mg/dl)
->2 Risk Factors (10-yr risk <10%) (<130 mg/dl) -0-1 Risk Factor (<160 mg/dl) |
|
Who are in the highest risk category for LDL levels?
|
-Those who already have developed CHD or who have a 10yr CHD risk similar to those with established CHD
-Other clinical forms of atherosclerosis (perip. arterial disease, abdom. aortic aneurysm, cerebrovascular disease) -Diabetes mellitus -Multiple risk factors conferring a 10yr risk of CHD >20% |
|
Who are in the middle risk category for LDL levels?
|
-Those with at least 2 risk factors for CHD (other than high LDL) conferring 10yr risk <20%
|
|
What are the CHD risk factors?
|
a. Cigarette smoking
b. Hypertension (SBP>140, DBP>90 or taking antihypertensive medication) c. Low HDL cholesterol (<40mg/dl) (HDL-c>60mg/dl is a negative risk factor, reduced total count by 1) d. Family history of premature CHD a. Male first degree relative <55yo b. Female first degree relative <65yo e. Age (men>45yo, women>55yo) |
|
What is the primary target in hyperlipidemia treatment? Secondary target?
|
Primary target: LDL
Secondary target: Non-HDL cholesterol in individuals with fasting triglyceride levels in the 200-499 range |
|
What are the categories of triglyceride levels?
|
-Normal (<150mg/dl)
-Borderline high (150-199mg/dl) -High (200-499 mg/dl) -Very high (>500 mg/dl) |
|
What are some clear reasons to treat elevated triglyceride levels?
|
-Very high levels pose a risk of pancreatitis and xanthomatosis
-High levels often occur as a manifestation of metabolic syndrome, an atherogenic constellation of effects of obesity and insulin resistance -High levels reduce concentration of HDL |
|
What should people with low HDL do?
|
-Exercise
-Achieve and maintain ideal weight -Cessation of smoking -Pharmacological measures in patients with CHD or CHD risk equivalent who have HDL <40md/dl |
|
Describe how lipid levels change through time
|
Serum lipid and lipoprotein concentrations normally increase with age. An acceptable level for cholesterol in a person 40 to 50 years old would be alarmingly high in a 10 yo child
|
|
How are cholesterol levels affected by MI?
|
Serum lipoprotein levels change dramatically immediately and for 6 weeks after a myocardial infarction. The plasma cholesterol, LDL and HDL levels may fall by as much as 60% in the first days after a heart attack
|
|
How does one estimate LDL levels
|
LDL = TC - Tg/5 - HDL
Tg = Fasting triglyceride levels Tg/5 is an estimate of VLDL |
|
What are the potential causes of secondary hyperlipidemia?
|
-Diabetes
-Hypothyroidism -Alcohol use -Nephrotic syndrome -Uremia -Hepatic disease -Dysglobulinemia -Porphyria |