Objective: To study the distribution patterns, amount, as well as the physical and chemical properties of malondialdehyde (MDA) and 4-hydroxynonenal (HNE) modified apolipoprotein B (apo B) in atherosclerotic lesions of human aorta. The distribution patterns of MDA and HNE modified apo B were also compared with those of lipoprotein(a) [LP(a)] and apo B.
Methods: Immunohistochemistry, electronic microscopy, immunoelectronic microscopic and biochemistry methods were used for qualitative and quantitative analysis.
Results: It was found that the distribution of MDA and HNE modified apo B coincided with Lp(a) and apo B in the extracellular matrix. While the distribution of MDA-apo B and HNE-apo B in foam cells appeared annular or particulate, similar to ceroids but different from that of Lp(a) or apo B. The physical and chemical properties of LDL from lesions on the intima were similar to those of in vitro modified LDL. In addition, a higher level of aldehyde modified LDL was extracted from the lesion areas than from normal intima.
Conclusion: Oxidative modification of apo B containing lipoproteins is necessary for atherogenesis.