Treating Hyperlipidemias Flashcards
What is the difference between a hyperlipidemia and a hyperlipemia?
- hyperlipidemia: elevations in any lipoprotein species
- hyperlipemia: elevation in triglycerides
What are lipoproteins?
high molecular weight complexes of specific proteins and lipids (e.g. VLDL, LDL, HDL) used to transport triglycerides and cholesterol in the blood
Why are hyperlipidemias a clinical problem?
because they can lead to acute pancreatitis or atherosclerosis
Which kind of cholesterol is shown to be beneficial and anti-atherogenic?
HDL
Which lipoproteins tend to contain more triglyceride?
larger, less dense ones
What is the role of chylomicrons?
they are synthesized in the enterocytes and transport dietary lipids into the circulation
What is the role of VLDL?
synthesized in hepatocytes, these transport fatty acids and cholesterol to peripheral tissues
What is the role of HDL?
transfer of cholesterol and apoliporztoeins among different lipoprotein subclasses and the liver
What is the role of LDL?
formed from remnants of depleted VLDL by the action of hepatic lipase, they are catabolized in hepatocytes via receptor-mediated endocytosis
Why is LDL problematic in patients?
because that which isn’t taken up by hepatic LDL receptors migrates into the vascular intima, to be taken up by scavenger receptors, oxidized, and accumulates in foam cells, damaging the intima via foam cell necrosis
Why is HDL good?
it decreases the amount of cholesterol available for tissue deposition by removing it from macrophages and promoting its return to the liver
Primary Hypertriglyceridemia
- a state of high triglycerides
- most commonly in the setting of familial hypertriglyceridemia but occasionally familial lipoprotein lipase deficiency or apoCII deficiency
- fibrates are the drug of choice
- treatment includes dietary change, weight reduction, exercise
Familial Hypercholesterolemia
- presents with high cholesterol and normal triglycerides
- due to a defect in the LDL-receptor
- cholesterol levels are elevated from birth and require treatment
- typically responds well to statins and other lipid lowering drugs
- homozygotes have worse disease than heterozygotes and may have CVD in childhood
Familial Defective ApoB100
- a mutation in ApoB100 leads to a decreased affinity for the LDL-receptor
- present with high cholesterol and normal triglycerides (a primary hypercholesterolemia)
- respond well to statins and niacin
Familial Combined
- a complex lipid profile of elevated cholesterol, LDL, and triglycerides, often with reduced HDL
- relatively common (1% prevalence)
- often presents with obesity, hyperinsulinemia, glucose intolerance, and mild hypertension
- requires treatment; usually statins in combination with fibrates
Dysbetalipoproteinemia
- a mixed hyperlipidemia resulting from an poE defect
- see an increase in chylomicrons and IDL-like particles
- present with elevated total cholesterol, LDL, and triglycerides, often with reduced HDL
- treatment involves decreasing fat and cholesterol intake along with niacin and fibrates
Risk of heart disease correlates with what lipid profiles?
- correlates with increased LDL and increased triglycerides
- inverse correlation with HDL