Plasma homocysteine in renal failure

Area of Science:

• Nephrology
• Clinical Chemistry
• Metabolic Disorders

Background:

• Elevated plasma homocysteine is a risk factor for cardiovascular disease.
• Chronic renal failure (CRF) is associated with various metabolic disturbances.
• The relationship between homocysteine levels and renal function requires further elucidation.

Purpose of the Study:

• To investigate plasma homocysteine levels in patients with varying degrees of chronic renal failure.
• To assess the impact of different dialysis modalities on homocysteine levels.
• To explore the mechanisms underlying homocysteine accumulation in CRF.

Main Methods:

• Plasma homocysteine levels were measured in control subjects and patients with CRF (without dialysis, CAPD, hemodialysis).
• Renal function was assessed by serum creatinine and glomerular filtration rate (GFR).
• Homocysteine and creatinine clearance were compared; methionine loading was performed in some patients.

Main Results:

• Plasma homocysteine was significantly increased in all CRF groups compared to controls.
• Patients with mildly reduced renal function (normal creatinine, reduced GFR) did not show elevated homocysteine.
• Homocysteine clearance as a percentage of creatinine clearance was increased in CRF patients, suggesting impaired tubular uptake.
• No significant diurnal variation in homocysteine was observed, but methionine loading caused a slight increase in severe CRF patients.

Conclusions:

• Chronic renal failure leads to elevated plasma homocysteine, independent of dialysis type.
• Impaired homocysteine clearance in CRF may involve reduced glomerular filtration and depressed tubular uptake.
• Disturbed homocysteine metabolism in CRF, possibly via the transsulphuration pathway, warrants further investigation.