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Plasma lecithin-cholesterol acyltransferase activities in uraemic patients
Insights
Plasma lecithin-cholesterol acyltransferase (LCAT) activity is reduced in dialysis patients. Heparin temporarily inhibits LCAT by increasing free fatty acids, with levels returning post-dialysis.
Area of Science:
- Nephrology
- Biochemistry
- Lipid Metabolism
Background:
- Plasma lecithin-cholesterol acyltransferase (LCAT) plays a crucial role in reverse cholesterol transport.
- Patients undergoing chronic dialysis often exhibit dyslipidemia, but the underlying mechanisms are not fully understood.
Purpose of the Study:
- To investigate plasma LCAT activity in patients on hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD).
- To examine the effect of heparin administration on LCAT activity in dialysis patients and healthy subjects.
Main Methods:
- LCAT activity was measured in 43 HD patients, 15 CAPD patients, and 19 healthy controls.
- The impact of intravenous heparin (100 U/kg) on LCAT activity was assessed before, during, and after hemodialysis sessions.
Main Results:
- LCAT activity was significantly lower in both HD and CAPD patients compared to normal subjects.
- Heparin administration inhibited LCAT activity, correlating with increased plasma free fatty acids.
- LCAT inhibition persisted throughout dialysis, returning to baseline levels one hour post-dialysis.
Conclusions:
- Dialysis patients exhibit reduced plasma LCAT activity, independent of other biochemical parameters studied.
- Heparin-induced LCAT inhibition is a transient effect linked to elevated free fatty acids.
- The precise cause of low LCAT in uremic plasma requires further investigation, but uraemic inhibitors are unlikely.
Abstract:
Plasma lecithin-cholesterol acyltransferase (LCAT) activity was measured in 43 haemodialysis and 15 peritoneal dialysis (CAPD) patients. LCAT activities in both groups of patients were significantly lower than those of normal subjects and did not correlate with any of the other biochemical parameters studied. The effect of intravenous administration of 100 U/kg of heparin on LCAT activity was examined in 21 haemodialysis patients and 19 normal subjects. Heparin inhibited LCAT activity by increasing plasma free fatty acid concentrations. LCAT remained inhibited throughout a dialysis session and returned towards pre-dialysis levels an hour after haemodialysis was discontinued. The cause of the low LCAT activities in the patients was not certain, but did not appear to be due to the presence of inhibitors in the uraemic plasma. The significance of these findings is discussed.