Lipoproteins blood levels

A better indication of a person s riidi of heart disease comes from a measurement of blood lipoprotein levels. Lipoproteins arc romfdex mol ecules with both lipid and protein parts that transport lipids through the body. They can be divided into four types ucconbiig to density as shown in 6tble 27.4. People with a high serum level high-density lipoproteins 4 HDL s) seem to have a decreased risk of heart disease. Asa rule of thumb, u person s risk drops about for each increase of 5 mg/dl.. in HDL con-... 

A woman was told by her physician to go on a low-fat diet. She decided to continue to consume the same number of calories by increasing her carbohydrate intake, while decreasing her fat intake. Which of the following blood lipoprotein levels would be decreased as a consequence of this diet ... 

The lipoprotein triacylglycerols in chylomicrons and VLDL are hydrolyzed to fatty acids and glycerol by lipoprotein lipase (LPL), an enzyme attached to endothelial cells of capillaries in muscle and adipose tissue. The enzyme found in muscle, particularly heart muscle, has a low for these blood lipoproteins. Therefore, it acts even when these lipoproteins are present at very low concentrations in the blood. The fatty acids enter muscle cells and are oxidized for energy. The enzyme found in adipose tissue has a higher and is most active after a meal when blood lipoprotein levels are elevated. 

The expected outcomes for die patient may include a dierapeutic response to dierapy (lowered blood lipid levels), management of common adverse drug reactions, and an understanding of die dietary measures necessary to reduce lipid and lipoprotein levels. 

Estrogens are thought to exert their cardiovascular effects by acting on blood lipoproteins or by direct effects on blood vessels. In studies performed in rats, fulvestrant had no effect on plasma cholesterol levels. When administered along with estradiol, however, it blocked the cholesterol-lowering activity of estradiol (Lundeen et al. 1997). 

Triacylglycerol in the forms of chylomicrons or very low density lipoproteins constitutes the mass transport system of fat in the blood. Excessive levels, particularly of VLDL, can give rise to various pathological problems which are grouped together under the title lipoproteinaemias and are discussed in Chapter 11 (Appendix 11.9). 

Although nicotinic acid and nicotinamide function identically as vitamins, their pharmacologic effects differ. In large doses (up to 6 g/day), nicotinic acid is effective in reducing serum lipids (low-density lipoprotein [LDL], high-density lipoprotein [HDL], triglycerides, and lipoprotein A. Nicotinic acid produces vasodilation and increased blood flow due to histamine release. Nicotinamide does not affect blood lipid levels or the cardiovascular system. 

Water soluble, high viscosity grade cellulose ether compositions are useful for the reduction of serum lipid levels, particularly total serum cholesterol, serum triglycerides and low density lipoprotein (LDL) levels, and/or attenuate the rise of blood glucose levels. The compositions may be in the form of a prehydrated ingestible composition, e.g. a gelatin, or a comestible, e.g. a biscuit. 

In contrast to saturated fats, unsaturated fats tend to increase blood HDL levels, which is desirable because these lipoproteins are effective at removing plaque from artery walls. 

Until 1993 apolipoprotein E was best known for its central role in plasma lipoproteins and cholesterol transport (Fig. 21-1). However, one of the three common alleles of the apoE gene confers a significant risk of development of Alzheimer disease.12171218 A high blood cholesterol level is also correlated with increased risk.12191220 Membrane abnormalities in mitochondria have been associated with Alzheimer disease.1221 Also related to membranes and lipid metabolism, vitamin E appears to combat Alzheimer disease.843 1218... 

Hyperlipidemia is a condition characterized by the presence of elevated lipoprotein levels in the blood. The term hyperlipidemia encompasses a number of different conditions, but it most often refers to high levels of cholesterol in the form of low-density lipoprotein (LDL). LDL cholesterol is often called bad cholesterol. High-density lipoprotein (HDL) is the good form of cholesterol. High LDL and/or low HDL levels are widely believed to be linked to increased heart disease risk. Because of the prevalence of hyperlipidemia in developed nations, antihyperlipidemic drugs are in high demand. 

Chylomicrons are triglyceride rich and contain apolipoprotein B-48 and the A types. The latter are synthesized in the intestinal tract cells. Additional apoproteins are transferred to the chylomicrons from HDL in circulation the apoE and apoC types. Their site of synthesis is the liver. The chylomicrons are subject to degradation by lipoprotein lipase in the peripheral tissue, especially adipose tissue. Lipoprotein lipase activity is increased by increased blood insulin levels. This enzyme is extracellular, attached to the capillary endothelial cells, and activated by ApoC-II, which is present in the chylomicrons. Lipoprotein lipase causes the hydrolysis of triglycerides, thus decreasing chylomicron size... 

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