The significance of plasma lysophospholipids in patients with renal failure on hemodialysis.

Abnormal phospholipid metabolism may play an important role in the progression of atherosclerosis in renal failure. We analyzed plasma phospholipid and lysophospholipid contents and fatty acid composition in the phospholipids of 18 patients with renal failure on hemodialysis (HD) and compared the levels with those of healthy controls. HD patients had a notably higher molar ratio of the plasma lysophosphatidylcholine (lysoPC)/phosphatidylcholine (PC) distributed from 0.072 to 0.207, and the control group showed a ratio lower than 0.150. Plasma phosphatidylethanolamine (PE) concentration significantly increased in HD patients compared with control subjects. A much higher level of plasma lysophosphatidic acid (lysoPA) (1.41 +/- 0.16 nmol/mL) was observed in HD patients compared with controls (0.54 +/- 0.08 nmol/mL). A strong correlation was found between plasma lysoPA and lysoPC concentrations (r = 0.609, p < 0.01) in HD patients. Serum inorganic phosphate (P) concentration was associated with the abnormal plasma lysoPC/PC, PE, and lysoPA levels in HD patients. Important decreases in eicosapentaenoic acid (EPA) of plasma PC and of dietary intake were observed in HD patients. Plasma thiobarbituric acid reactive substance (TBARS) concentration was negatively correlated with the amount of vitamin E intake in both subjects. These findings demonstrated the specific characteristics of the abnormal phospholipid metabolism in HD patients. The cause and consequences of elevated lysoPC/PC molar ratio and lysoPA in the plasma of HD patients remain to be established.