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Relationships between homocysteine and related amino acids in chronic hemodialysis patients.
Clin Nephrol 2001; 55(6):465-70CN

Abstract

AIMS

Homocysteine (Hcy) has emerged as an important risk factor for atherosclerotic disease. Elevated levels in chronic dialysis patients may contribute to high vascular mortality, but little is known about levels of related amino acids in this group. In an observational study in the clinical setting we sought to document these.

METHODS

In 114 hemodialysis patients pre-dialysis total plasma homocysteine, vitamin B12 and red blood cell (RBC) folate concentrations were measured. In a subgroup of patients (n = 42), other plasma amino acids were measured pre- and post-dialysis. All patients were routinely taking oral folic acid supplements (1.2 mg per week).

RESULTS

Elevated homocysteine concentrations were found in all patients (geometric mean 33.1 umol/l, range 13.8 - 69.2 umol/l, laboratory reference range (RR) 3-13 umol/l). RBC folate levels were high (1223 +/- 54.5 nmol/l mean +/- SE, RR 300 - 710 nmol/l) and inversely related to pre-dialysis plasma Hcy (r = -0.44, p < 0.001). Hcy levels were not related to vitamin B12 levels. A history of vascular disease was not associated with higher concentrations of Hcy. Hcy clearance on dialysis was substantial (mean Hcy reduction 33 +/- 14%). While plasma methionine levels were normal, serine levels were significantly lower than the reference range (59.3 +/- 2.39 umol/l (mean +/- SE, RR 70 - 195 umol/l)) and directly related to levels of glycine (r = 0.52, p < 0.001). Glycine levels were within normal range. Although overall levels were low, higher serine levels were related to elevated homocysteine (r = 0.42, p < 0.01). Dialytic loss of glycine, serine and methionine was moderate.

CONCLUSION

An inverse association between RBC folate and homocysteine levels extended to 3 times the upper limit of normal for folate, suggesting a role for high dose folic acid supplementation in the treatment of renal-failure related hyperhomocysteinemia. Low serine levels are expected as it is primarily synthesized in the kidney. The direct relationship between serine and homocysteine is consistent with the reported lack of effect of serine supplements on high Hcy levels.

Authors+Show Affiliations

Department of Biochemistry, Flinders Medical Centre, Adelaide, Australia. stephenm@menzies.edu.auNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

11434358

Citation

McDonald, S P., et al. "Relationships Between Homocysteine and Related Amino Acids in Chronic Hemodialysis Patients." Clinical Nephrology, vol. 55, no. 6, 2001, pp. 465-70.
McDonald SP, Whiting MJ, Tallis GA, et al. Relationships between homocysteine and related amino acids in chronic hemodialysis patients. Clin Nephrol. 2001;55(6):465-70.
McDonald, S. P., Whiting, M. J., Tallis, G. A., & Barbara, J. A. (2001). Relationships between homocysteine and related amino acids in chronic hemodialysis patients. Clinical Nephrology, 55(6), pp. 465-70.
McDonald SP, et al. Relationships Between Homocysteine and Related Amino Acids in Chronic Hemodialysis Patients. Clin Nephrol. 2001;55(6):465-70. PubMed PMID: 11434358.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Relationships between homocysteine and related amino acids in chronic hemodialysis patients. AU - McDonald,S P, AU - Whiting,M J, AU - Tallis,G A, AU - Barbara,J A, PY - 2001/7/4/pubmed PY - 2001/11/3/medline PY - 2001/7/4/entrez SP - 465 EP - 70 JF - Clinical nephrology JO - Clin. Nephrol. VL - 55 IS - 6 N2 - AIMS: Homocysteine (Hcy) has emerged as an important risk factor for atherosclerotic disease. Elevated levels in chronic dialysis patients may contribute to high vascular mortality, but little is known about levels of related amino acids in this group. In an observational study in the clinical setting we sought to document these. METHODS: In 114 hemodialysis patients pre-dialysis total plasma homocysteine, vitamin B12 and red blood cell (RBC) folate concentrations were measured. In a subgroup of patients (n = 42), other plasma amino acids were measured pre- and post-dialysis. All patients were routinely taking oral folic acid supplements (1.2 mg per week). RESULTS: Elevated homocysteine concentrations were found in all patients (geometric mean 33.1 umol/l, range 13.8 - 69.2 umol/l, laboratory reference range (RR) 3-13 umol/l). RBC folate levels were high (1223 +/- 54.5 nmol/l mean +/- SE, RR 300 - 710 nmol/l) and inversely related to pre-dialysis plasma Hcy (r = -0.44, p < 0.001). Hcy levels were not related to vitamin B12 levels. A history of vascular disease was not associated with higher concentrations of Hcy. Hcy clearance on dialysis was substantial (mean Hcy reduction 33 +/- 14%). While plasma methionine levels were normal, serine levels were significantly lower than the reference range (59.3 +/- 2.39 umol/l (mean +/- SE, RR 70 - 195 umol/l)) and directly related to levels of glycine (r = 0.52, p < 0.001). Glycine levels were within normal range. Although overall levels were low, higher serine levels were related to elevated homocysteine (r = 0.42, p < 0.01). Dialytic loss of glycine, serine and methionine was moderate. CONCLUSION: An inverse association between RBC folate and homocysteine levels extended to 3 times the upper limit of normal for folate, suggesting a role for high dose folic acid supplementation in the treatment of renal-failure related hyperhomocysteinemia. Low serine levels are expected as it is primarily synthesized in the kidney. The direct relationship between serine and homocysteine is consistent with the reported lack of effect of serine supplements on high Hcy levels. SN - 0301-0430 UR - https://www.unboundmedicine.com/medline/citation/11434358/Relationships_between_homocysteine_and_related_amino_acids_in_chronic_hemodialysis_patients_ L2 - https://medlineplus.gov/dialysis.html DB - PRIME DP - Unbound Medicine ER -