Lesson 104 - Abnormalities of Lipid Metabolism

What makes up triglycerides?

3 long chain fatty acids and glycerol

How are lipids transported in blood?

lipoproteins

What makes up lipoproteins?

triglyceride or cholesterol and protein

What is the main sterol?

cholesterol

What is the function of cholesterol?

cell membranes and hormones

What is the function of triglycerides and fatty acids?

energy source

What is lipemia?

lipids in blood causing turbin appearance

What does lipemia increase the concentration of?

bile acids and calcium

What does lipemia decrease the concentration of?

sodium and chloride

What can lipemia also affect?

liver, pancreatic enzymes, bilirubin, glucose

What is hyperlipemia?

increase lipid concentration in serum

What does hyperlipidemia occur?

after ingesting a meal

What is fasting hyperlipidemia?

abnormal lipid increase

What causes fasting hyperlipidemia?

metabolism or endocrine disease

What is hyperlipoproteinemia?

increase lipid proteins

Does hyperlipidemia always result in lipemia?

No

What lipid is usually causing hyperlipemia?

triglycerides

What does not cause lipemia?

hypercholesterolemia

What amount of TGs cause turbidity?

>100 mg/dL

What amount of TGs cause lactescent?

>1000 mg/dL

What is exogenous lipemia?

chylomicrons

What is endogenous lipemia?

very low density lipoproteins

Which lipemia is caused by dietary fat?

exogenous lipemia

Which lipemia is caused by excess production by liver?

endogenous lipemia

What does exogenous lipemia look like?

fat rises to the top to form a cream

What does endogenous lipemia look like?

turbidity uniformly present

What happens to density with lipoproteins as protein content is increased?

density increases

How do we get cholesterol?

ingested or produced by the liver

What is the process for synthesizing cholesterol?

complex mulistep process through Acetyl CoA

What are other tissues that produce cholesterol?

gonads and adrenals

How do we get triglycerides?

ingestion of synthesized in the liver

What is the starting point for triglycerides in non-ruminants?

glucose

What is the starting point for triglycerides in ruminants?

acetate

What is the most important protein in the blood that breaks down chylomicron?

lipoprotein lipase

What happens if you have a deficiency in lipoprotein lipase?

prolonged VLDLs in the circulation leading to lipemia

What are the types of hyperlipemia?

physiologic, primary, secondary

What is physiologic hyperlipemia?

in dogs and cats increase chylomicrons post-prandial

When do you expect chylomicrons to be cleared?

<8 hrs

If there is delayed clearing of chylomicrons, what should you think?

secondary hyperlipidemia

What is primary hyperlipemia?

congenital defect in lipoprotein lipase or apoprotein CII enzymes

What causes secondary hyperlipemia?

pancreatitis, cholestasis, hypothyroidism, diabetes mellitus, cushings, obesity, high fat diets, drugs

How long should you fast patient before collecting blood?

8 hours

What is familial in miniature schnauzers?

primary hyperlipidemia

What age is primary hyperlipidemia?

> 4 yrs

What can chronic hyperlipidemia result in?

increase ALP, abdominal pain, pancreatitis, seizures

What other breeds have primary hyperlipidemia?

beagles, poodles, shelties

What is primary hyperlipidemia in cats?

Type III LPL deficiency in himalayan, siamese, DSH

What are the clinical signs of primary hyperlipemia in dogs?

vomiting, diarrhea, pancreatitis, diabetes, seizures

What are clinical signs of primary hyperlipemia in cats?

multiple hematomas affecting peripheral nerves causing loss of sensation, paralysis, horners syndrome, muscle atrophy, cutaneous xanthomas, lipemia retinalis

What is cutaneous xanthomas?

lipid-laden macrophages in the skin

What animals have primary hypercholesterolemia?

doberman pinschers, rottweilers, briards

How does hypothyroidism cause secondary hyperlipemia?

decrease cholesterol uptake and decrease hepatic lipase degradation of cholesterol to bile acids

What will the serum cholesterol be in hypothyroidism?

markedly increased with mild TG increase

What is the result of secondary hyperlipemia due to hypothyroidism?

vascular disease, subsequent neurologic or cardiac abnormalities

How does diabetes mellitus cause hyperlipemia?

decrease insulin which decreases lipoprotein lipase activity which decreases intravascular lipolysis

What levels will be increase with secondary hyperlipemia due to diabetes mellitus?

hyperlipoproteinemia, increase triglycerides, increase cholesterol

How does cushings cause secondary hyperlipemia?

steroids increase synthesis of VLDL by the liver and increases hormone sensitive lipase which increases fatty acid influx

How does steroids affect insulin and the affect of that with hyperlipemia?

steroids antagonize insulin which will decrease LPL activity

What levels will be increased with cushings secondary hyperlipemia?

increase cholesterol and triglycerides

How does acute pancreatitis cause secondary hyperlipemia?

cholestasis or diabetes maybe

What is increased in acute pancreatitis secondary hyperlipemia?

increase triglycerides and/or cholesterol and increase VLDLs

What levels will be increased with cholestatic hepatic disease?

increase cholesterol and triglycerides

What is nephrotic syndrome?

protein losing glomerulonephropathy

How does nephrotic syndrome cause secondary hyperlipemia?

decrease lipolysis of lipoproteins with apoprotein B, decrease intravascular processing, stimulate VLDL synthesis in hepatocytes

What levels will be affected in nephrotic syndrome?

increase cholesterol, increase triglycerides, hypoalbuminemia

What is obesity?

excessive hepatic synthesis of VLDL

What animals get hepatic lipidosis?

lactating dairy cows, pregnancy toxemia in sheep/goats, anorexia obese cats, anorexic equids and camelids

What are common diseases associated with hyperlipemia in horses?

pars pituitary intermedia dysfunction, colic, laminitis, GI parasites

What causes severe hypertriglyceridemia in horses?

small equids during any systemic diseases that produces negative energy balance like starvation, chronic illness, obesity, pregnancy, lactation, stress, etc.

Why do horses get increase VLDL production in negative energy balance?

have poorly developed pathways for ketone production so produce VLDL instead

What causes hyperlipemia in camelids?

negative energy balance situations like stress, anorexia, pregnancy, lactation

What does hyperlipemia lead to in horses and camelids?

hepatic lipidosis

What are ruminants inefficient with?

inefficient transportation of VLDL from the liver

What is the test for negative energy balance in cows?

non esterified fatty acids

What is the test for ketosis in cows?

B-hydroxy butyrate

What cows likely develop ketosis?

dairy cows in late lactation

What causes ketosis in sheep and goats?

pregnancy toxemia

What causes hypolipidemia?

chronic liver disease, PSS, GI/pancreatic disease

What GI/pancreatic disease causes hypolipidemia?

maldigestion, malabsorption, protein losing enteropathy, lymphangiectasia, starvation