Thrombotic events of arteriovenous fistulae in hemodialysis patients related to the C677T thermolabile variant of methylenetetrahydrofolate reductase
| Autor: | Hernán Trimarchi, Genoud, J. Schropp, M. Forrester, María Mercedes Castañon, E. Freixas, Lucía Kordich, H. Pereyra |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
medicine.medical_specialty
Hyperhomocysteinemia Methionine Homocysteine biology business.industry medicine.medical_treatment medicine.disease Gastroenterology Surgery chemistry.chemical_compound chemistry Nephrology Internal medicine Methylenetetrahydrofolate reductase Methylcobalamin biology.protein Medicine Vitamin B12 Hemodialysis Thermolabile business medicine.drug |
| Zdroj: | The journal of vascular access. 5(2) |
| ISSN: | 1129-7298 |
| Popis: | Background Hyperhomocysteinemia is a risk factor for thrombosis, a frequent complication of vascular access (VA) in hemodialysis (HD). The enzyme methylenetetrahydrofolate reductase (MTHFR) is necessary for the remethylation of homocysteine (Hcy) to methionine. It has been postulated that patients homozygous and, to a lesser extent, heterozygous for the C677T thermolabile variant of this enzyme present a reduced catalytic activity, with secondary increases in plasmatic Hcy levels (normal: 10 ± 5 μmol/L) and an elevated risk of vascular thromboses. Methods Sixty-two patients on chronic HD were divided into two groups: group A (n = 23, 37.1%) was normal for the enzyme (CC); group B (n = 39, 62.9%) was heterozygous (CT). Both groups were not different according to age, sex, time on HD, hematocrits (Hct), baseline levels of Hcy, folic acid and vitamin B12. After the 1st HD session patients were started on folic acid 10 mg/day and 500 μg/week of intravenous (i.v.) methylcobalamin. Results Two years later, thrombotic events were not different between the two groups. Group A = 5 (21.7%) vs. group B = 12 (30.7%), Hcy levels were significantly different between final and baseline measurements (group A 21.5 ± 5.2 vs. 16.6 ± 3.9 μmol/L, p = 0.02; group B 22.1 ± 8.9 vs. 16.1 ± 3.9 μmol/L, p = 0.008), folic acid (group A 22.1 vs. 346.9 ng/ml, range (r) = 166–527, p12 (group A 1489 vs. 3192.3 pg/ml, r = 1494–4890, p = 0.01; group B 1086 vs. 1513.8 pg/ml, r = 1092–1934, p = 0.02). Conclusions HD patients heterozygous for the C677T variant of the enzyme MTHFR can present a similar risk of thrombotic events in arteriovenous fistulae (AVF) compared to patients normal for the enzyme at a 1-yr follow-up. These results could be explained by an adequate control of Hcy levels after folic acid and methylcobalamin replacement therapy. |
| Databáze: | OpenAIRE |
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