CC - LIPIDS 2 Flashcards
Transport of hepatic-derived lipids
Endogenous Pathway
IN Endogenous Pathway, ______ loses core lipids once secreted in the circulation
VLDL
Loss of core lipids leads to conversion of VLDL to _____
remnants
About half of the remnants are converted to ____, and half are taken in by the ____
LDL ; liver
- Mediated by HDL
- Excess cholesterol from peripheral cells is transported back to the liver
Reverse Cholesterol Transport Pathway
HDL serves to taxi cholesteryl esters to chylomicrons/VLDL remnants to liver
Reverse Cholesterol Transport Pathway
Conversion of cholesterol into bile acids for removal
Reverse Cholesterol Transport Pathway
Specimen Collection for Lipid Analysis
- Serum
- Fasting
preferred specimen
12 hour fast preferred
avoid _____, Presence of fat droplets suspended in a solution.
lipemia
Lipemia affects assays by affecting absorbance due to ______ of light
refraction
high plasma lipid concentrations can cause excessive plasma _____ and interfere with _________
turbidity ; spectrophotometric methods
Concentration differs between men, women and children due to ________. ______ and _______
sex hormone, concentration, and age
- Higher HDL
- Lower Cholesterol, triglyceride
is seen in
Women
As aging, Men and women increase in ______, _______ and ______
total cholesterol, LDL cholesterol and triglyceride
Colorimetric measurement procedures are less costly but are subject to ________ substances and may require _________ and ________
interfering ; extraction steps ; strong acids
Classical method
Liebermann-Burchard
Liebermann-Burchard is involved extraction & hydrolysis. Uses _____ & ______
sulfuric ; acetic acids
In Liebermann-Burchard, results in formation of a ______, proportional to the __________.
green color ; cholesterol concentration
Anything that affects HDL & LDL levels will affect cholesterol concentration-because these lipoprotein contain increased ______
cholesterol
______ level inversely affects cholesterol level
Thyroxine
hypothyroid associated with ________
hyper cholesterol
hyper thyroid associated with _______
hypo cholesterol
documented that post-menopausal women have increased LDL cholesterol
Estrogen
altered endocrine function resulting in increased cholesterol
Pregnancy
Other factors include ______, _______, ________, and _________
hepatitis, nephrotic syndrome, emotional stress and diabetes mellitus
Dextran sulfate or phosphotungstate acid with magnesium chloride precipitates LDL and VLDL lipoproteins
Precipitation Reaction
HDL left in the supernatant is tested using cholesterol assay. The answer represents the amount of HDL in the sample
Precipitation Reaction
Elevated triglyceride levels - level exceeds 400 mg/dL
Drawbacks
Detergents or enzymes binds sites of VLDL and LDL particles. HDL is then left to react with colored products and can be measured
Homogeneous Reaction
Dsiadvantages (Homogenous Reaction)
lacks specificity for HDL
desirable range for HDL
> 60 mg/dL
gray-area for HDL
40-59 mg/dL
high risk level of HDL
< 40 mg/dL
- Enzymatic
- Colorimetric
- Involve the liberation of glycerol by lipase
Triglyceride Measurement Methods
recommended triglyceride range
< 150 mg/dL
triglyceride borderline high
150-199 mg/dL
very high triglyceride level
> 500 mg/dL
Friedewald estimation ( calculation ) is used for ___ measurement
LDL measurement
Total Cholesterol, Total Triglycerides and HDL with routine procedure
Estimate the LDL with the following :
LDL= Chol- HDL -VLDL
and VLDL= Triglycerides/5
LDL Measurement
stems from the deposition of lipids in artery walls.
Arteriosclerosis
Result of malfunctions in the synthesis, transport or catabolism of lipoproteins
Hyperlipoproteinemia
Elevated lipoprotein levels
Hyperlipoproteinemia
Hyperlipoproteinemia divisions
/Hypercholesterolemia
/Hypertriglyceridemia
/Combined hyperlipidemia: elevation of cholesterol and triglyceride
- Linked to heart disease
- Familial hypercholesterolemia (FH)
- Genetic abnormality that predisposes people to high cholesterol levels, specifically LDL cholesterol.
- Make cholesterol normally but lack or are deficient in active LDL receptors, so LDL builds up in the circulation .
- Without the LDL receptors, LDL cannot be bound and cholesterol cannot be transferred into the cell
Hypercholesterolemia
- Imbalance between synthesis and clearance of VLDL in circulation
- Deficiency of LDL or apo-C ( co-factor for LPL activity)
- Chylomicrons cannot be cleared and triglycerides remain high
- Normal function is for LDL to hydrolyze triglycerides carried in the chylomicrons and VLDL to give cells energy
Hypertriglyceridemia
causes of Hypertriglyceridemia
genetic abnormalities such as Familial hypertriglyceridemia
secondary causes of Hypertriglyceridemia
Hormonal abnormalities in pancreas, adrenals, pituitary and of diabetes mellitus
Hypertriglyceridemia is Influenced by many hormones such as
- Insulin, glucagon, pituitary growth hormone, adrenocorticotropic hormone (ACTH), thyrotropin, epinephrine, norepinephrine,
Hormones trigger lipase can cause _____ and _______
acute and recurrent pancreatitis
- Presence of elevated levels of serum cholesterol and triglycerides
- Results from accumulation of cholesterol-rich VLDL and chylomicron remnants from defective catabolism
- Risk factor for CHD
- Primarily congenital
Combined Hyperlipoproteinemia
Low levels of lipoproteins
Hypolipoproteinemia
2 forms of Hypolipoproteinemia
- Hypoalphalipoproteinemia
- Hypobetalipoproteinemia
- Decrease in circulating HDL (< 40 mg/dL)
- Lack of hypertriglyceridemia
- Due to a genetic defect (Tangier Disease)
Hypoalphalipoproteinemia
Low levels of LDL cholesterol
Hypobetalipoproteinemia
Absence of lipoproteins containing Apo-b
Abetalipoproteinemia
Abetalipoproteinemia includes
LDL and VLDL
Abetalipoproteinemia results in
Difficulty in weight gain and growth
Fat absorption problems
RBC membrane defects
Usually effects infants
activate hormone-sensitive lipase in adipose tissue, thereby increasing the supply of fatty acids for oxidation in other tissues, and inactivate acetyl-CoA carboxylase.
Glucagon and Epinephrine
regulates the levels of acetyl-CoA carboxylase and fatty acid synthase by controlling their rate of synthesis.
Insulin
complete absence of HDL with very low levels of apoAI and apoAII due to inheritance of homozygous recessive alleles.
Tangier disease
Tangier disease results to accumulation of cholesterol esters in
liver, spleen, lymph nodes, cornea, skin
(Familial chylomicronemia)
– elevated chylomicron due to ineffective or
insufficient LPL
Fredrickson type 1
(Primary hypercholesterolemia)
- increased LDL
Fredrickson type II
(Familial dysbetalipoprotinemia)
- increased IDL
Fredrickson type III
(Familial hypertriglyceridemia)
- increased VLDL
Fredrickson type IV
markedly increased triglyceride
Fredrickson type V
deficiency of β –glucocerebrosidase
Gaucher’s disease
deficiency of sphingomyelinase
Niemann – Pick disease
accumulation of galactocerebroside-β – galactosidase
Krabbe’s disease
deficient α – galactosidase A
Fabry’s disease
deficiency in hexosaminidase A
Tay-Sachs disease
