title: Evidence of altered homocysteine metabolism in chronic renal failure.
abstract: The fasting serum concentrations of total homocysteine and metabolites of transsulfuration (cystathionine, cysteine, methylmalonic acid, 2-methylcitric acid) and remethylation (methionine) were determined by gas chromatography-mass spectrometry in 40 nondialyzed patients with chronic renal disease and in 50 patients with end-stage renal disease requiring chronic maintenance hemodialysis. The nondialyzed patients and 28 of the dialysis patients did not receive additional vitamin supplementations. Twenty-two of the dialysis patients received daily oral vitamin preparations containing 10 mg pyridoxine (vitamin B(6)), 6 microg cyanocobalamin (vitamin B(12)), and 1 mg folic acid. In the nondialyzed patients, linear regression analysis showed positive correlations between serum concentrations of creatinine and total homocysteine (r = 0.68, p < 0.0001), cystathionine (r = 0.73, p < 0. 0001), methylmalonic acid (r = 0.77, p < 0.0001), and 2-methylcitric acid (r = 0.81, p < 0.0001). Serum homocysteine was positively correlated with serum concentrations of cystathionine (r = 0.59, p < 0.0001), cysteine (r = 0.69, p = 0.004), methylmalonic acid (r = 0. 64, p = 0.0001), and 2-methylcitric acid (r = 0.64, p < 0.0001). There was no significant correlation between serum concentrations of homocysteine and methionine (r = -0.14, p = 0.63). In the hemodialysis patients receiving oral vitamin supplementation, serum homocysteine and cystathionine concentrations were significantly lower than in hemodialysis patients not receiving vitamins (homocysteine 21.8 +/- 1.1 vs. 33.2 +/- 3.7 micromol/l, p = 0.0004; cystathionine 2,075.9 +/- 387.1 vs. 3,171.3 +/- 680.2 nmol/l, p = 0. 02; mean +/- SEM). In summary, our results show increased intermediate products of the transsulfuration pathway, but no increase in remethylation of homocysteine in chronic renal disease, including end-stage renal disease requiring chronic maintenance dialysis.
authors.affiliation: Medizinische Klinik I, Marienhospital Herne, University of Bochum, Germany.
authors.forename: B F
authors.initials: BF
authors.lastname: Henning
authors.forename: R
authors.initials: R
authors.lastname: Riezler
authors.forename: M
authors.initials: M
authors.lastname: Tepel
authors.forename: K
authors.initials: K
authors.lastname: Langer
authors.forename: H
authors.initials: H
authors.lastname: Raidt
authors.forename: U
authors.initials: U
authors.lastname: Graefe
authors.forename: W
authors.initials: W
authors.lastname: Zidek
mesh_terms: D001161:Arteriosclerosis / Q000209:etiology / Q000517:prevention & control; D002951:Citrates / Q000097:blood; D003404:Creatinine / Q000097:blood; D003540:Cystathionine / Q000097:blood; D003545:Cysteine / Q000097:blood; D005260:Female; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000378:metabolism* / Q000628:therapy; D008297:Male; D008715:Methionine / Q000097:blood; D008764:Methylmalonic Acid / Q000097:blood; D008875:Middle Aged; D006435:Renal Dialysis; D012307:Risk Factors; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood
chemical_list: D002951:Citrates; D014815:Vitamins; D006710:Homocysteine; D003540:Cystathionine; C031605:2-methylcitric acid; D008764:Methylmalonic Acid; D008715:Methionine; D003404:Creatinine; D003545:Cysteine