Plasma homocysteine concentration changes after renal transplantation in children.

Hyperhomocysteinemia, a risk factor for vascular disease, is found in children as well as in 80% of adult patients with end-stage renal disease. The aim of this study was to assess the changes in plasma homocysteine concentrations after renal transplantation (RT). Plasma homocysteine, vitamin B(12), and folate concentrations were prospectively measured in six patients at three points, before and post transplantation (6 months, 4 years), and compared with controls using standardized scores (Z score) for each of these parameters. Folic acid supplementation was introduced after the evaluation at 6 months. Patients had elevated median plasma homocysteine Z scores during dialysis (4.12). When assessed at 6 months and 4 years, median plasma homocysteine Z scores were, respectively, 2.35 and 0.29. Median folate Z scores were 1.89 during dialysis, -0.26 at 6 months, and 3.26 at 4 years post RT. Median vitamin B(12) Z score was 2.12 during dialysis, 0.58 at 6 months, and -0.07 at 4 years post RT. Glomerular filtration rate (GFR) improved after RT, with median GFR of 84.5 ml/min per 1.73 m(2) at 6 months. This stabilized to a value of 70.5 ml/min per 1.73 m(2) at 4 years. When comparing values before and after RT at 6 months, changes were observed only for GFR ( P<0.03) and vitamin B(12) ( P<0.05). There were no changes in plasma homocysteine, folate, and serum albumin. At 4 years, a significant decrease in plasma homocysteine was observed ( P<0.05) with increased GFR ( P<0.03). No significant changes were observed in plasma albumin, folate, and vitamin B(12) concentrations. In conclusion, elevated plasma homocysteine in children during dialysis persists after RT despite a significant improvement in renal function. However, normalization was attained when patients were supplemented with folic acid. Further controlled studies are required to evaluate the determinants and treatment of elevated plasma homocysteine in pediatric transplant patients.