NUR226- HLD

cholesterol

lipids, essential structural component of animal cell membranes

exogenous cholesterol

25% of cholesterol; dietary

endogenous cholesterol

75% of cholesterol

manufactured mu cells from the liver

uses saturated fat

HDL

“good” cholesterol

50% protein, 20% cholesterol, 5% triglycerides

want a higher amount of this cholesterol

decreases lipid in blood vessels

LDL

“bad” cholesterol

20-25% protein, 45-55% cholesterol, 5-10% triglycerides

desired to be lower

blood serum after eating a high fat meal

cloudy and dense

normal amount of total cholesterol in the body

<200 mg/dL (ranges from 100-200)

normal amount of HDL in males

>45 mg/dL

normal amount of HDL in females

>55 mg/dL

normal amount of triglycerides in the body

<150 mg/dL (ranges from 40-150)

normal amount of LDL in males

< 0.5 mg/dL

normal amount of LDL in females

<4.5 mg/dL

function of HDL

absorbs excess cholesterol in the blood and transports it to the liver

function of LDL

delivers cholesterol to the tissues

function of VLDL

transports triglycerides and cholesterol to tissues; can cause atherosclerosis

atherosclerosis

injury to endothelium: coronary arteries and peripheral arterial walls; thickening or hardening of the arterial wall

causes of atherosclerosis

smoking, chronic hemodynamic wall stress (HTN), hyperglycemia

hyperlipidemia/hypercholestermia

too much cholesterol in the body

>200 mg/dL of cholesterol in the body:

hyperlipidemia

risk factors for HLD

smoking, diet, physical activity, HTN, family hx, age, genetics

modifiable risk factors for HLD

smoking, diet, physical activity

what happens in familial hypercholesterolemia

liver can’t efficiently remove LDL from the blood caused by a defect in LDL receptors in liver cells; leads to elevated LDL cholesterol level in the blood

How does atherosclerosis affect cholesterol?

elevated LDL and cholesterol

sequence of progression of atherosclerosis

injury

increased permeability

LDL molecules into vessel wall

damaged endothelium

macrophages arrive- engulf lipids

release of inflammatory mediators

excess lipids and debris accumulate in vessel wall

plaque with large lipid core prone to rupture

ruptured plaque- platelet aggregation- thrombus formation

statins

drugs that inhibit the production of cholesterol and LDL in the liver

decrease the risks of stroke, CAD, CVD, atherosclerosis, mortality

usually taken at night because liver makes cholesterol at night

ischemia

tissues don’t get enough oxygen

infarction

death of tissue from lack of oxygen

thrombus

clot formation

Coronary artery disease

caused by atherosclerosis, low oxygen delivery to the heart

HMG-CoA reductase inhibitor (statins)

inhibits cholesterol production in liver and more LDL removed from blood

can prevent CAD, stroke, decrease mortality

effect of HMG-CoA reductase inhibitor on cholesterol

decreases LDL and triglycerides, increases HDL

adverse reactions to HMG-CoA reductase inhibitor

myopathy (weakness, cramps), rhabdomyolysis(breakdown of muscle fibers and acute kidney failure), hepatotoxicity``

HMG-CoA reductase inhibitor drug example

atorvastatin (Lipitor)

secondary causes of HLD

diet, drugs, diseases, disorders, altered metabolism

increases LDL and triglycerides

bile acid sequestrants function

decrease LDL by preventing absorption of cholesterol and promoting excretion

where is bile produces

liver

how does the liver produce bile

metabolizes cholesterol

a class of drugs that help lower cholesterol levels by binding to bile acids in the gastrointestinal tract

bile acid sequestrants

example of bile acid sequestrant

cholestyramine (Questran)

(can decrease absorption of other drugs)

niacin function

increase effectiveness of some statins to decrease LDL and increase HDL

niacin + lovastatin

Advicor

niacin + simvastatin

Simcor

nicotinic acid effects

decrease LDL 14-20%

increase HDL 22-26%

decrease TG 28-35%

nicotinic acid adverse reactions

flushing and hot flashes, hyperglycemia, hyperuricemia, UGI distress, hepatotoxicity (injury to liver function)

fibric acid derivatives (fibrates) function

lipid lowering agents (if TG levels are elevated; decrease secretion of LDL by liver

How do fibric acid derivatives (fibrates) affect VLDLs

accelerate their clearance

How do fibric acid derivatives (fibrates) affect TG?

increase drug breakdown and elimination

(drug of choice for increased TG levels)

How do fibric acid derivatives (fibrates) affect HDL

facilitate HDL formation

effects of fibric acid derivatives (fibrates)

decrease LDL 6-10%

decrease VLDL up to 50%

increase HDL 10-20%

decrease TG 20-50%

fibric acid derivatives (fibrates) adverse reactions

dyspepsia, gallstones, myopathy

example of fibric acid derivatives (fibrates)

gemfibrozil (Lopid)

consideration for fibric acid derivatives (fibrates)

avoid with liver or kidney disease and statins as it can increase the risk of myopathy and rhabdomyolysis

myopathy

disease that affects the muscles that control voluntary movement

rhabdomyolysis

a serious medical condition that occurs when muscle tissue breaks down and releases its contents into the bloodstream.

cholesterol absorption inhibitor function

blocks absorption of cholesterol in jejunum- dietary and cholesterol secreted in bile

example of cholesterol absorption inhibitor

ezetimibe (Zetia)

ezetimibe + simvastatin

vytorin

cholesterol absorption inhibitor in combination with statin effect:

15-20% greater decrease in LDL than either alone

effects of cholesterol absorption inhibitor

decrease LDL 19%

increase HDL 1-4%

decrease TG 5-10%

adverse reactions of cholesterol absorption inhibitor

headache, myalgia, arthralgia, abdominal pain, diarrhea

fish oil constituents

omega-3 polyunsaturated fatty acids

high doses of fish oil (1-4g) function

decrease TG levels

low doses of fish oil (850mg- 1g) function

decrease platelet aggregation, thrombosis, and inflammation

examples of fish oil types

mackerel, halibut, herring, salmon, albacore tuna, trout

goal for consumption of fish oil

1g/day

consideration with fish oil

careful with allergies to shellfish and seafood