Serum levels of total homocysteine, homocysteine metabolites and of advanced glycation end-products (AGEs) in patients after renal transplantation.

Aims: Hyperhomocysteinemia has been described as an independent risk factor for cardiovascular diseases (CVD) influencing patient outcome. Advanced glycation end-products (AGEs) are involved in the pathogenesis of vascular damage in uremia. This study was undertaken to assess whether high serum levels of total homocysteine (tHcy) with its metabolites methylmalonic acid (MMA), methylcitric acid (MCA) and cystathionine (CYSTA) as well as elevated serum concentrations of the AGEs pentosidine and Nepsilon-carboxymethyllysine (CML) are independent risk factors for CVD, left ventricular hypertrophy (LVH) or hypertension as well as kidney dysfunction in renal transplant recipients (RTR).

Methods: Serum levels of tHCy, MMA, MCA and CYSTA were measured by a gas chromatographic-mass spectrometric assay, pentosidine by HPLC and CML using an ELISA assay.

Results: All measured parameters were significantly higher in RTRs than in healthy subjects (p < 0.0001). The levels of pentosidine and CML as well as of tHcy and its metabolites correlated significantly with each other, but not with those ofMMA and CYSTA. Significant correlations were also found between pentosidine and tHcy, MMA or MCA as well as between CML, MMA and MCA, respectively. Acute or chronic rejection did not influence these values. No significant differences were observed between patients with or without CVD or with hypertension. In RTRs with LVH, only the tHcy levels were significantly higher than in those RTRs without LVH (p = 0.006). Logistic regression analysis revealed an independent influence of tHcy on the presence of LVH.

Conclusion: These results may indicate an association between high tHcy values and LVH. Further investigation is needed to determine whether a reduction of tHcy and Hcy metabolites and/or AGE serum concentrations would significantly improve patient outcome after undergoing renal transplantation.