Correlation between Oxidized Low Density Lipoproteins and von Willebrand Factor in Chronic Renal Failure

Abstract

SummaryAn ELISA specific for a wide spectrum of oxidized apo B-100 in OxLDL was developed and applied to blood samples from 27 control subjects, 20 mild chronic renal failure (MCRF) patients, 21 severe chronic renal failure patients on conservative treatment (SCRF) and 56 severe chronic renal failure patients on maintenance hemodialysis (HEMO). Mean levels of OxLDL were 0.59 mg/dl in controls (95% Cl, 0.52-0.66 mg/dl), and were 2.7-fold (p <0.01), 3.1-fold (p <0.001) and 5.4-fold (p <0.001) higher in MCRF, SCRF and HEMO patients, respectively. Levels of von Willebrand factor, a marker of endothelial injury, were 100 percent in controls (95% Cl, 90-110 percent), and were 1.5-fold (p = NS), 1.6-fold (p <0.01) and 2.1-fold (p <0.001) higher in MCRF, SCRF and HEMO patients, respectively. Multiple regression analysis revealed that the extent of renal failure (F = 14; p = 0.0004) accounted for a significant fraction of the variation in OxLDL levels, also after exclusion of patients with evidence of ischemic atherosclerotic disease (F = 21; p = 0.0001). After adjustment for the extent of renal failure, hemodialysis (F = 5.6; p = 0.021) and LDL cholesterol levels (F = 7.1, p = 0.0095) contributed significantly to the variation in OxLDL levels. Whereas the extent of renal failure contributed only marginally to the individual variations in vWF levels (F = 4.1; p = 0.048), these levels correlated significantly with plasma levels of OxLDL (F=26; p=0.0001). In conclusion, atherogenic OxLDL increase progressively during the development of renal failure suggesting that the oxidation of LDL may be associated with endothelial injury and atherogenesis in these patients.

Oxidized Low Density Lipoproteins in Patients With Transplant-Associated Coronary Artery Disease

“…15 Standard preparations of MDA-modified and copper-oxidized LDL were prepared as described elsewhere 16,17 and were used as assay control subjects. 10 Characterization of modified LDL involved measurement of thiobarbituric acid-reactive substances, determination of electrophoretic mobility on 1% agarose gels, quantification of cholesterol and fatty acids by high-performance liquid chromatography on a Nova-Pak C18 reversed-phase column (Waters Associates), and quantification of proteins by Lowry assay and of phospholipids by enzymatic assay (Biomérieux). 18 Oxidized LDLs were isolated from the purified LDL fractions of patients by fast flow chromatography on a mono-QSepharose column.…”

“…We have demonstrated that the specificity of the mAb E6 depends on the extent of protein modification only. 10 All lipoprotein concentrations were therefore expressed in terms of protein.…”

“…10 Standard oxidized LDL and plasma samples were diluted in PBS containing antioxidants and antiplatelet agents as described above. Equal volumes of diluted, purified mAb 4E6 solution (final concentration, 7.5 ng/mL) and of diluted standard solution (copper-oxidized LDL added as a competing ligand at a final concentration ranging between 50 and 500 ng/mL) were mixed and incubated for 30 minutes at room temperature.…”

“…10,18 Immobilized antigens for this assay included native LDL prepared from pooled human plasma (protected against in vitro oxidation as described above), copper-oxidized and MDA-modified LDL, and human serum albumin. The plasma samples were diluted 40-fold and incubated for 2 hours at room temperature in the coated microtiter plates.…”

“…In the present study we have used an ELISA that is highly specific for oxidized LDL. 10 The ELISA was used to study the association between plasma levels of oxidized LDL and CAD. …”