Altered low density lipoproteins in peripheral vascular disease patients

Several studies have shown that peripheral vascular disease (PVD) patients have abnormal lipoproteins. The mechanism whereby this abnormal lipid metabolism influences arterial occlusive disease in these PVD patients is not known. In the present study we found that low density lipoproteins (LDL) obtained from PVD patients have lower affinity to B receptor of normal fibroblasts compared to LDL obtained from control subjects. The nanograms of 125I LDL bound per milligram of B receptor was 254 +/- 19 for LDL from control subjects, 152 +/- 12 for LDL from PVD without diabetes, and 108 +/- 8 for PVD with diabetes (P less than 0.01). Further, the preincubation of LDL obtained from PVD patients with pentoxifylline (xanthine derivative used for PVD) increased the binding affinity of the LDL to B receptor sites from 107 +/- 9 to 210 +/- 34 (P less than 0.01). There was no significant difference in the binding properties of LDL with fibroblasts either from PVD patients (254 +/- 19) or control subjects (267 +/- 22) (P greater than 0.5), thereby suggesting that the number of receptor sites may be the same in both types of fibroblasts. From these results it can be concluded that defect in the metabolism of LDL may promote arterial occlusive disease seen in the PVD patients.