Prognostic value of tryptophan load test followed by serum kynurenine determination. It's comparison with pyridoxal-5-phosphate, kynurenine, homocysteine and neopterin amounts

Tryptophan load test followed by serum kynurenine determination at fasting state and after L-tryptophan loading, as well as serum pyridoxal-5-phosphate (P-5-P), homocysteine and neopterin concentrations at fasting state have been examined in 30 healthy individuals and 87 patients with coronary heart disease (CHD), verified by coronary angiography. Received results have shown that low serum P-5-P concentration as well as P-5-P deficiency identified by tryptophan load test have been found in 78% of CHD patients, while increased homocysteine concentration above 15 μmol/L in 31.8%, and elevated neopterin concentration above 8.7 nmol/L in 32.1% of cases. It allows to conclude that a lot of CHD patients have P-5-P deficiency. Moreover P-5-P deficiency is an earlier indicator of CHD than increased homocysteine level above 15 μmol/L. Elevated serum neopterin concentration above 8.7 nmol/L may be a marker of coronary disease activity rather than a marker of the presence of CHD.