Fat-bottomed girls (Lipid transport) Flashcards
Pancreatic lipase
Degradation of dietary TG in small intestine
Lipoprotein lipase (LPL)
Degradation of TG circulating in chylomicrons & VLDLs
Hepatic TG lipase
Degradation of TG remaining in IDL
Hormone-sensitive lipase
Degradation of TG stored in adipocytes
Lecithin-cholesterol acyltransferase
aka LCAT
Catalyzes esterification of cholesterol
Cholesterol ester transfer protein
aka CETP
Mediates transfer of cholesterol esters to other lipoprotein particles
Hyperchylomicronemia
Type I familial dyslipidemia
Increased chylomicrons
Elevated TG, cholesterol
LPL deficiency or altered apolipoprotein C-II (LPL cofactor)
Causes pancreatitis, hepatomegaly, & eruptive/pruritic xanthomas
*No increased risk for atherosclerosis!
Familial hypercholesterolemia
Familial dyslipidemia type IIa
Increased LDL
Elevated cholesterol
AD absence or decrease of LDL receptors
Causes accelerated atherosclerosis (heart attacks in 20s!), tendon xanthomas, & corneal arcus
Hypertriglyceridemia
Family dyslipidemia type IV
Increased VLDL
Elevated TG
Hepatic overproduction of VLDL. Causes pancreatitis
Abetalipoproteinemia
Hereditary inability to synthesize lipoproteins due to deficiencies in apoB-100 (Binds LDL recepto) & apoB-48 (Mediates chylomicron secretion)
AR; symptoms occur in 1st few months of life
Intestinal biopsy –> accumulation win enterocytes
Findings: failure to thrive, steatorrhea, acanthocytosis, ataxia, night blindness
Roles of the 5 types of lipoproteins
Chylomicrons- deliver dietary TGs to peripheral tissue; deliver cholesterol to liver as chylomicron remnants (depleted of triacylglycerols); secreted by intestinal epithelial cells
VLDL- Delivers hepatic TGs to peripheral tissue; secreted by liver
IDL- Formed in the degradation of VLDL; delivers triglycerides & cholesterol to liver to be degraded to LDL
LDL- Delivers hepatic cholesterol to peripheral tissues; formed by LPL modification of VLDL in peripheral tissue; taken up by target cells via receptor-mediated endocytosis
HDL- Mediates reverse cholesterol transport from periphery to liver; acts as a repository for apoC and apoE (needed for chylomicron & VLDL metabolism); secreted from both liver & intestine
Statins MOA
HMG-CoA reductase inhibitors
Significantly decrease LDL; slight increase in HDL; minimal decrease in TGs
Inhibit cholesterol precursor, mevalonate; upregulate apo B/E receptors on hepatocytes
SE: Hepatotoxicity, rhabdo, teratogenic
Niacin MOA
Inhibits lipolysis in adipose tissue; reduces hepatic VLDL secretion into circulation
Significantly increases HDL; decreases LDL & triglycerides
SE: Red, flushed face (pre-treat w/ aspirin)
Hyperglycemia, hyperuricemia (look out for gout)
Resins
Prevent intestinal reabsorption of bile acids; liver must use cholesterol to make more
Decreases LDL, slightly increases HDL, increases triglycerides
SE: It tastes NASTY; causes GI discomfort, decreased absorption of fat soluble vitamins; cholesterol gallstones
Ezetimbe
Prevents reabsorption of cholesterol at small intestine brush border
SE: rarely increases LFTs
