BACKGROUND: It has been demonstrated that the products of tryptophan degradation,kynurenamines, play an important role in senile cataract formation. However, the involvement of thesecompounds in the development of diabetic cataract has not been studied. The aim of the present studywas to compare the concentration of tryptophan and kynurenamines in the aqueous humor and lenses obtainedfrom non-diabetic and diabetic patients with cataract.
MATERIAL AND METHODS: The concentration of tryptophan,kynurenine, 3-hydroxykynurenine, kynurenic acid and anthranilic acid was measured using high-performanceliquid chromatography (HPLC) with appropriate detection in aqueous humor and lenses obtained from 38non-diabetic subjects and 20 patients with type II diabetes in course of surgical cataract extraction.
RESULTS:In diabetic patients the concentration of kynurenine, 3-hydroxykynurenine and anthranilic acid in theaqueous humor was increased in comparison with non - diabetic subjects, while the concentration of tryptophanand kynurenic acid was similar in both groups. In the lenses obtained from patients with diabetes accumulationof tryptophan and all of its assayed metabolites was observed.
CONCLUSIONS: Concentrations of the productsof kynurenine pathway of tryptophan degradation in the aqueous humor and the lenses of diabetic patientsare increased. We suggest that these compounds could play an important role in the development of diabeticcataract.

Keywords: kynurenamines, diabetes