Biology

In this weeks lecture that membrane fluidity is a function of the kinds of fatty acids and the cholesterol content within that membrane Is there any evidence that hyperlipidemia for example could change membrane composition If that is the ca

Hyperlipidemia and Membrane Composition Lipids are an important source of energy to our body in the absence of glucose. They are stored in the body in the form fat and circulate in the form of Low, intermediate and high density lipoproteins. Hyperlipidemia is a condition in which there is an increase in the amount of these circulating lipoproteins. Hyperlipidemias are divided into different classes according to the increase in the amount of specific lipoproteins and the pathology behind it.
The mammalian cell membrane is a lipid bilayer membrane. They have a central hydrophilic layer incorporated in between the two hydrophobic layers of lipids. Lipids serve as the major structural and functional components of the membrane. The major function of the lipids is to maintain the fluidity of the membrane. They also serve as important channels through which lipid soluble substances diffuse in and out of the cell while lipid insoluble substances pass through specific protein channels.
As mentioned earlier that the lipids are an important component of the cell membranes, they are also affected by an increase or decrease in the amount of circulating lipids in the body. The increased amount of lipids in the body leads to an increased number of fatty acids. These increased free fatty acids are taken up by cell membranes of many ells of the body, the most important of which are erythrocytes, immune cells and platelets. The increased fatty acid content of the cell membrane helps to retain its fluidity of the membrane but, on the other hand it also affects the enzymatic activity of the membrane due to oxidative damage to membrane proteins (Fatty acids: physiological and behavioral functions, 2001). The alteration in the structure and function of erythrocyte due to increased incorporation of fatty acid was found to be a cause of their hemorheological behavior leading to many diseases. The major protein channel affected by this was Na-K ATPase transporter (Koter M et al, 2004).
Atherosclerosis, a diseased characterized by increased aggregation of platelets was also found to be caused by increased lipid content of the body. Increased amount of arachidonic acid in platelets cell membrane was thought to be a cause of this increased platelet aggregation (omega-3 fatty acids and health, 1995).
Apart from all the adverse of hyperlipidemias on membrane composition and function, they have been found to be rather helpful in patients with epilepsy. Increases lipid content decreases one’s susceptibility to seizures as increased fatty acids in the membrane affects the protein channels leading to decreased firing capacity of neuronal and glial cells (Fatty acids: physiological and behavioral functions, 2001).
REFERENCES
1. Koter, M, I Franiak, K Strychalska, M Broncel, and J Chojnowska-Jezierska. "Damage to the Structure of Erythrocyte Plasma Membranes in Patients with Type-2 Hypercholesterolemia." The International Journal of Biochemistry &amp. Cell Biology. 36.2 (2004): 205-215. Print.
2. Nettleton, Joyce A. Omega-3 Fatty Acids and Health. New York: Chapman &amp. Hall, 1995. Prin
3. Mostofsky, David I, Shlomo Yehuda, and Norman Salem. Fatty Acids: Physiological and Behavioral Functions. Totowa, N.J: Humana Press, 2001. Print

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