Lipoprotein(a)

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Lipoprotein(a) (also called LP(a) and Lp-a) is a lipoprotein subclass. Lp-a is a risk factor for Coronary heart disease and other vascular diseases.

Contents 1 Metabolism 2 Populations 3 Function 4 Lipoprotein(a) and Disease 5 Cardiology diagnostic tests 6 See also 7 References 8 External links

[edit] Metabolism

Lipoprotein(a) is assembled in the blood from Low density lipoprotein (LDL) molecules and glycoprotein molecules called apolipoprotein-a (apo-a). Plasma apo-a is secreted by the liver. The mechanism and sites of Lp(a) catabolism are unknown.

[edit] Populations

Lp-a is genetically linked with concentrations varying over one thousandfold, from < 0.2 to > 200 mg/dL. African populations have Lp-a concentrations severalfold higher than Caucasians and Asian populations.

[edit] Function

Lipoprotein(a) recruits inflammatory cells through interaction with Mac-1 integrin.

[edit] Lipoprotein(a) and Disease

High Lp(a) in blood is a risk factor for coronary heart disease (CHD), cerebrovascular disease (CBD), atherosclerosis, thrombosis, and stroke. Lp-a concentrations may be affected by disease states, but are only moderately affected by diet, exercise, and other environmental factors. Lipid-reducing drugs have no effect on Lp(a) concentration.

High Lp(a) predicts risk of early atherosclerosis similar to high LDL, but in advanced atherosclerosis, Lp(a) is an independent risk factor not dependant on LDL. Lp(a) then indicates a coagulant risk of plaque thrombosis. Apo(a) contains domains that are very similar to plasminogen (PLG). Lp(a) accumulates in the vessel wall and inhibits binding of PLG to the cell surface, reducing plasmin generation which increases clotting. This inhibition of PLG by Lp(a) also promotes proliferation of smooth muscle cells. These unique features of Lp(a) suggest Lp(a) causes generation of clots and atherosclerosis.^[1]

[edit] Cardiology diagnostic tests

Lipoprotein(a) - Lp(a)

Desirable: < 14 mg/dL

Borderline risk: 14 - 30 mg/dL

High risk: 31 - 50 mg/dL

Very high risk: > 50 mg/dL

[edit] See also

• Lipoprotein
• Apolipoprotein
• Very low density lipoprotein
• Low density lipoprotein
• Combined hyperlipidemia

[edit] References

• Beyond Cholesterol, Julius Torelli MD, 2005 ISBN 0-312-34863-0 page 91.
• Hidden Causes of Heart Attack and Stroke, Christian Wilde, 2003 ISBN 0-9724959-0-8 pages 182-183.

1. ^ Caplice et al.

[edit] External links

• Lipoprotein(a) summary by Utermann
• Lipoprotein(a) as a Risk Factor for Preclinical Atherosclerosis, by Schreiner, et al. (pdf)
• Lipoprorein(a) linked to thrombosis, by Caplice et al.
• Lipoprotein(a) in atherosclerotic plaques recruits inflammatory cells, by Sotiriou, et al.