Determinants of Fasting Total Serum Homocysteine Levels in Liver Transplant Recipients

Abstract

Objectives: Homocysteine (HCY) is a sulfur-containing amino acid considered to be a marker for a relative folate deficiency. Hyperhomocysteinemia is a known risk factor for development of cardiovascular disease, vascular dementia, depression, and possibly some carcinogeneses. Liver transplant recipients have an increased risk for cardiovascular disease because of a high incidence of obesity, arterial hypertension, diabetes mellitus, and hyperlipidemia. The aim of this study is to elucidate the determinants for hyperhomocysteinemia as an additional risk factor in these patients.

Materials and Methods: Seventy stable liver transplant recipients, 48 men (mean age, 50 ± 11 years) and 22 women (mean age, 52 ± 13 years) had their serum homocysteine levels tested after orthotopic liver transplantation. For mainstay immunosuppression, 53 patients were treated with tacrolimus, 10 with cyclosporine, 3 with mycophenolate mofetil, and 4 with sirolimus. Fasting blood samples were obtained and analyzed immediately (within 1 hour) for total serum homocysteine by high-performance liquid chromatography.

Results: In all patients, mean homocysteine levels were 22.7 ± 14 µmol/L (normal range, 9-15 µmol/L). Forty-six patients were found to have homocysteine levels > 15 µmol/L, and all 70 recipients had homocysteine levels > 9 µmol/mL. In our patients, increased homocysteine levels correlated well with body mass index and renal function. Homocysteine levels in patients receiving cyclosporine were higher than those in patients receiving tacrolimus (22.3 ± 6 vs 17.9 ± 12 µmol/L, P < .05).

Conclusions: Overall, homocysteine levels are significantly increased in liver transplant recipients. Homocysteine levels correlate well with obesity, renal function, and the particular immunosuppressant protocol. Therefore, a specific treatment for patients after liver transplantation (eg, one with folates) might reduce the risk of complications resulting from hyperhomocysteinemia.