anti ox-LDL ELISA

Lipid peroxidation is a natural process essential for cell growth. However, when the
oxidative stress overwhelms the antioxidative cell defense, the balance is disturbed
and enhanced formation of lipid peroxidation products occurs. At present, lipid peroxidation
is considered to be one of the basic mechanisms involved in the initiation
and progression of many diseases. Various studies have provided evidence that oxidative
stress resulting in lipid peroxidation and protein modification is involved in
the pathogenesis of atherosclerosis and coronary heart disease.
Lipid peroxidation products are formed during normal cell metabolism via producing
an excess of free radicals that can react with unsaturated fatty acids, in particularly
low-density lipoprotein (LDL), the major carrier of plasma cholesterol. LDL is
eliminated by macrophages. Normally, receptor-mediated uptake of LDL is suppressed
through down-regulation of LDL receptor expression in response to increasing
cholesterol levels. Once LDL is oxidised, it is still internalised by macrophages
but through scavenger receptors whose expression is not controlled by cholesterol
loading. The binding of oxidised LDL (ox-LDL) is the step by which cholesterol accumulation
in macrophages is induced transforming them into lipid-loaded ‘foam
cells’. This process is accompanied by extensive cell proliferation and elaboration of
extra cellular matrix components and contributes to the genesis and progression of
atherosclerosis by promoting endothelial damage and amplifying the inflammatory
response within the vessel wall. Cholesterol-loaded macrophage ‘foam cells’ are present
in the earliest detectable atherosclerotic lesions, the precursor of more complex
atherosclerosis that cause stenosis and limited blood flow. These advanced lesions
ultimately represent the sites of thrombosis leading to myocardial infarction.
Oxidised LDL is not only an essential trigger of arteriosclerosis and vascular ageing.
When modified by the oxidation LDL becomes immunogenic. Specific auto antibodies
against epitopes (e.g. malondialdehyde-Lysine) of oxidised LDL in serum have
been detected. Auto antibodies against oxidised low density lipoprotein have been
found in sera of patients with a number of different symptoms, like diabetes, vascular
diseases, carotid arteriosclerosis and others. The ox-LDL antibodies recognise tissues
with atherosclerotic lesions. The titer of oxidised LDL antibodies is considered as an
independent indicator for the progress of atherosclerosis.