Lege Artis Medicinae

[Ways and tools of the organism's defence in atherosclerosis - The mysterious HDL particle]

JAKAB Lajos

JANUARY 27, 2009

Lege Artis Medicinae - 2009;19(01)

[Every type of injury elicits an immediate defending, preventing response in the living organism, which involves the whole organism’s participation. In case of a single effect, the events and symptoms together can be designated as “acute phase reaction syndrome”. The pathogenic constituents' effects on the arterial wall are, however, permanent, though varying in composition and intensity. The protecting reaction serving the prevention of the continuously arising vessel wall lesion is inflammation itself. Beginning of the inflammatory phenomenon carries within itself the criteria of the acute tissue response but it takes on involuntarily chronic features as a consequence of the chronic etiology. In the arterial wall ongoing vasculitis affects all the three layers of the vessels. The HDL particle is involved in triggering and progression of vasculitis. It transports cholesterol from the tissues to the liver, defends the integrity and physiological functions of the endothelium, exerts antioxidant effects, and it has the capacity to inhibit secretion and effects of cytokines, cell migration and the thrombotic process. These are all together serving as controllers of the ongoing vasculitis in the artery wall. Composition of the HDL particle is exceptionally complex. Almost half of the identifiable - at least 48 - components could be considered as acute phase reactants, and almost as many are related to cholesterol and lipoprotein metabolism. Participation of proteinase inhibitors and complement system components and regulators is very important for its function. Some constituents have a glycosaminoglycan binding capacity. The physiological roles of some acute phase reactants are not completely identified as today. This is especially valid concerning the characteristics of the HDL particle as an entity. Nevertheless, on the basis of present study data, it is ascertainable that HDL is an acute phase reactant; it is an inherent part of the natural, innate immune system of the organism. However, it is only one single component of the large group of the anti-inflammatory mechanisms and factors.]

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