Serum homocysteine concentration in kidney transplant recipients

Kim, Yeo Kyeoung; Lee, Youn Kyoung; Lee, Kyun Sang; Cho, Min Seok; Jeong, Taek Kyun; Park, Byoung Seok; Jeong, Gyun Ho; Ma, Seong Kwon; Kim, Soo Wan; Kim, Nam Ho; Choi, Ki Chul

Abstract

BACKGROUND: Cardiovascular disease (CVD) after kidney transplantation is a major cause of both graft loss and patient death in kidney transplant recipeints. There are several well known risk factors of CVD, such as hyperlipidemia, hypertension, diabetes melitus, old age and smoking. Non-classic risk factors are acute rejection episode, LVH, C-reactive protein and hyperhomocysteinemia. Homocysteine is an amino acid filtered through the glomerulus and hyperhomocysteinemia is considered as a risk factor of CVD in end-stage renal disease (ESRD) and kidney transplant patients. So homocysteine lowering trials, such as folic acid and vitamine supplement therapy, are being made. We evaluated the prevelance and determinants of hyperhomocysteinemia in kidney transplant recipients.
METHODS
We measured serum total homocysteine concentration (tHcy) and its determinants in 21 normal persons, 37 chronic renal failure (CRF) patients with conservative treatment (predialysis) and 48 kidney transplant patients.
RESULTS
The prevalence of hyperhomocysteinemia was 4.8%, 83.8% and 45.8% among normal persons, predialysis and kidney tranplant patients, respectively. Among the kidney transplant recipients the prevelence of hyperhomocysteinemia was 18.8% in normal renal function (serum creatitine concentration male: below 1.2 mg/dL, female: below 1.1 mg/dL) group and 59.4% in abnormal renal function group. The tHcy values in kidney transplant patients are significantly lower than those in predialysis patients (16.38+/-6.48 nmol/L vs. 24.68+/-9.01 nmol/L, p < 0.01), but higher than those in normal persons (16.38+/-6.48 nmol/L vs. 8.80+/-2.07 nmol/L, p < 0.01). Among the kidney transplant recipients the tHcy values in normal creatinine group are significantly lower than those in abnormal creatinine group (12.02+/-3.68 nmol/L vs. 18.57+/-6.51 nmol/L, p < 0.01). Using muliple regression analysis, this study showed increased serum creatinine concentration is a major determinant of tHcy concentrations in kidney transplant recipients and hyperhomocysteinemia is not correlated with whole blood trough level of cyclosporin (mean 126.26+/-62.19 ng/mL, range: 26~322 ng/mL) or vitamines supplement therapy.
CONCLUSION
In this study the serum homocysteine values in kidney transplant recipients were higher than in normal control group but significantly lower than in CRF patients with conservative treatment. The major determinant for serum homocysteine concentration is a serum creatinine concentration.