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Lipid and lipoprotein levels in undialyzed patients with chronic renal failure
Insights
Uremic men exhibit altered lipid profiles, with lower high-density lipoprotein (HDL) cholesterol and higher triglycerides compared to healthy individuals. Undialyzed patients show better lipid levels than those on dialysis, with racial differences observed in lipid and apoprotein levels.
Area of Science:
- Nephrology
- Cardiovascular Medicine
- Clinical Biochemistry
Background:
- Chronic kidney disease (CKD) is associated with significant alterations in lipid metabolism.
- Uremia, the buildup of waste products in the blood due to kidney failure, profoundly impacts lipoprotein profiles.
- Understanding these lipid changes is crucial for managing cardiovascular risk in CKD patients.
Purpose of the Study:
- To compare lipid and lipoprotein levels in undialyzed uremic men with healthy controls.
- To evaluate lipid profiles of undialyzed uremic patients in comparison to those undergoing dialysis.
- To investigate potential racial differences in lipid metabolism among undialyzed uremic men.
Main Methods:
- Measurement of serum lipid and lipoprotein levels (HDL, LDL, triglycerides, cholesterol) in three groups: undialyzed uremic men, dialyzed uremic men, and healthy controls.
- Assay of lecithin: cholesterol acyl transferase (LCAT) activity using both endogenous and exogenous substrates.
- Assessment of the rate of reverse cholesterol transport (RCT) from HDL to other lipoproteins.
- Analysis of apoprotein A-I and B levels and their correlation with HDL levels, stratified by race (black vs. white patients).
Main Results:
- Undialyzed uremic men had lower HDL cholesterol and higher triglycerides than healthy controls.
- Undialyzed patients demonstrated more favorable lipid profiles (higher HDL, cholesterol, triglycerides) compared to dialyzed patients.
- LCAT activity was reduced in undialyzed patients when using an exogenous substrate, and RCT was significantly impaired.
- Black undialyzed patients exhibited lower cholesterol and triglycerides, higher HDL and HDL3, elevated apoprotein A-I, and reduced apoprotein B compared to white patients. A strong correlation between apoprotein A-I and HDL was noted in black patients.
Conclusions:
- Uremia significantly dysregulates lipid metabolism, leading to an atherogenic lipid profile.
- Lipid abnormalities appear to worsen with dialysis, suggesting potential benefits of managing lipids before dialysis initiation.
- Racial variations in lipid profiles and apoprotein levels exist in uremic populations, influencing cardiovascular risk and HDL metabolism.
Abstract:
Lipid and lipoprotein levels were measured in undialyzed uremic men and compared with levels of healthy control subjects. The patients had lower high-density lipoprotein (HDL) cholesterol (mean +/- SD, 46.3 +/- 14.8 vs 54.1 +/- 18.2 mg/dl) and increased serum triglycerides (197 +/- 151 vs 142 +/- 87.7 mg/dl). When compared with patients maintained on dialysis, the undialyzed patients had higher HDL cholesterol (46.3 +/- 14.8 vs 30.3 +/- 13.3 mg/dl), serum cholesterol (226 +/- 81 vs 151 +/- 42 mg/dl), and triglycerides (197 +/- 151 vs 146 +/- 105 mg/dl). The low-density lipoprotein (LDL): high-density lipoprotein cholesterol ratios were 3.78, 3.24, and 2.84 in the dialyzed, undialyzed, and control groups, respectively. Lecithin: cholesterol acyl transferase activity of undialyzed patients was similar to controls when measured by an endogenous substrate assay (148 +/- 112 vs 112 +/- 28 nmol/ml/hr), but were significantly lower when assayed using exogenous substrate (73.3 +/- 25.6 vs 112.8 +/- 7 nmol/ml/hr). The rate of cholesterol transfer (RCT) from HDL to very low density lipoprotein and LDL was in the following order: dialyzed patients (1.85 +/- 1.29 mg/dl/hr) less than undialyzed patients (2.41 +/- 1.57 mg/dl/hr) less than control subjects (4.83 +/- 3.13 mg/dl/hr). Within the undialyzed patient group, black patients had lower serum cholesterol and triglycerides and higher HDL and HDL3 cholesterol than white patients. Apoprotein A-I levels were higher and apoprotein B levels were lower in the black patients. There was a strong correlation (r = 0.9501) between apoprotein A-I and HDL levels in the black patients, but not in the white patients (r = -0.148).(ABSTRACT TRUNCATED AT 250 WORDS)