Relation of kynurenine/tryptophan with immune and inflammatory markers in coronary artery disease.

BACKGROUND

Inflammation and immune activation have a crucial role in the pathogenesis of cardiovascular diseases. Indolamine 2,3-dioxygenase, a tryptophan catabolising enzyme, is up-regulated with various inflammatory stimuli. The aim of this study was to evaluate the relationship of tryptophan degradation with immune and inflammatory markers in coronary artery disease.

METHODS

57 subjects undergoing coronary angiography were recruited. 18 subjects with normal coronary arteries according to Gensini scoring were selected as a control group and the rest of subjects were included in patient group. Serum tryptophan and kynurenine levels were determined with HPLC-UV method, and kynurenine/tryptophan ratio was evaluated as IDO activity. Serum neopterin and myeloperoxidase activity were measured by ELISA method.

RESULTS

While the kynurenine/tryptophan ratio and neopterin levels were similar in both groups, the patient group had higher myeloperoxidase and hs-CRP levels than controls (p = 0.02, p = 0.002, respectively). The kynurenine/tryptophan ratio was correlated with neopterin in both groups (r = 0.389, p = 0.025; r = 0.683, p = 0.002, respectively) and with hs-CRP in patients (r = 0.637, p = 0.001). Also, neopterin levels were correlated with hs-CRP in patients (r = 0.755, p = 0.0001).

CONCLUSIONS

Our results are in line with a role of inflammation in coronary artery disease. The study provides evidence that IDO activity is related with immune and inflammatory states. Also, the study was performed in a limited hospital-based population. Further studies are warranted in the larger groups.