Homocysteine, its metabolites, and B-group vitamins in renal transplant patients.
BACKGROUND
Increased plasma total homocysteine (tHcy) levels are an independent risk factor for cardiovascular morbidity in patients with normal and impaired renal function, including stable renal transplant recipients (RTRs). Plasma concentrations of the metabolites of Hcy, such as cystathionine (Cys), methylmalonic acid (MMA), 2-methylcitric acid (MC), and its diastereomers MCI and MCII have been reported in only a few articles. We therefore looked for the serum concentration of these metabolites and their relationship to renal function, cardiovascular diseases, the immunosuppressive treatment, and serum concentrations of cobalamin and folate.


METHODS
Fifty RTRs (mean age 50.4 +/- 11.8 years, 35.9 +/- 44.4 months after kidney transplantation) and 35 controls (NP; mean age 43.5 +/- 14.4 years) were studied. Total Hcy and its metabolites were measured by gas chromatography-mass spectrometry (GC-MS).


RESULTS
Total Hcy, MMA, Cys, and MC were elevated twofold to sixfold as compared with NP, with a significant interrelationship between these compounds. With the exception of Cys, they were significantly correlated with serum creatinine. Serum folate levels were inversely correlated with tHcy, Cys and cobalamin with MMA and the ratio of MCI/MCII. There was no correlation between tHcy concentration and its metabolites with immunosuppressive treatment (CsA vs. FK506), clinical history, or current findings of cardiovascular complications and blood pressure profile.


CONCLUSIONS
Prospective studies are needed to find out whether the lowering or normalization of serum concentrations of tHcy and its metabolites due to treatment with B vitamins should be achieved to reduce the cardiovascular risk and improve the long-term outcome of allografts and of patients.
Stein
G
G
Department of Internal Medicine IV, Institute of Pharmacology, Friedrich-Schiller-University of Jena, Jena, Germany. guenter.stein@polkim.med.uni-jena.de
Müller
A
A
Busch
M
M
Fleck
C
C
Sperschneider
H
H
D000328:Adult; D002318:Cardiovascular Diseases / Q000209:etiology; D016022:Case-Control Studies; D005260:Female; D006710:Homocysteine / Q000378:metabolism*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000150:complications / Q000188:drug therapy; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014803:Vitamin B Complex / Q000627:therapeutic use*
D007166:Immunosuppressive Agents; D006710:Homocysteine; D014803:Vitamin B Complex