Hyperhomocysteinemia and the presence of cardiovascular disease are associated with kynurenic acid levels and carotid atherosclerosis in patients undergoing continuous ambulatory peritoneal dialysis.

INTRODUCTION

Hyperhomocysteinemia and the activation of kynurenine (KYN) pathway have been reported as the factors participated in atherosclerosis in uraemic patients. The objective of this study was to verify whether hyperhomocysteinemia may be involved in atherosclerotic cardiovascular disease (CVD) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

MATERIALS AND METHODS

We determined the plasma concentrations of KYN, KYNA, KYNA/KYN ratio, homocysteine (Hcy) and intima-media thickness (IMT) - an early reflection of the systemic atherosclerosis in CAPD patients both with and without CVD and healthy controls.

RESULTS

KYNA concentrations and KYNA/KYN ratio were about 3 times higher in the patients with hyperhomocysteinemia (Hcy>15μM) compared to those with normal Hcy levels (<15μM), and they were significantly lower in CVD[+] than in CVD[-] patients in these studied groups. The presence of CVD was associated with higher Hcy levels only in the patients with Hcy>15μM. The positive association was between Hcy and KYNA, KYNA/KYN ratio in all CAPD patients and in CVD[+] patients with hyperhomocysteinemia. IMT was positively associated with Hcy levels in patients with hyperhomocysteinemia, whereas there was no relationship between IMT and KYNA concentrations in the studied groups.

CONCLUSIONS

These results showed the association between hyperhomocysteinemia and carotid atherosclerosis as well as the possible role of hyperhomocysteinemia in the activation of KYNA production in CAPD patients. The elevated KYNA levels observed in patients with hyperhomocysteinemia seem to be protective against Hcy-mediated atherosclerosis in these patients.