Objectives of the study: The aim of this study was to set up methods for estimation of two important markers of advanced damage caused by oxidative and carbonyl stresses – advanced glycation end products (AGEs) and advanced oxidation protein products (AOPP) and to determine their levels in the serum of patients with diabetes mellitus and in haemodialyzed patients. Methods: AGEs were assessed fluorimetrically (excitation 350 nm, emission 440 nm) and are expressed in arbitrary (fluorescence) units (FU) and as fluorescence per gram of protein (FU/g). AOPP were measured spectrophotometrically according to Witko-Sarsat (absorbance at 340 nm) and are expressed in chloramine units (mmol/l). AGEs and AOPP are stable in serum frozen at –80 °C for 3 months. Coefficients of variation of these methods are 3.21 % for AGEs estimation and 3.31 % for AOPP detection. Results: Both AGEs and AOPP were elevated in diabetics (AGEs 3.39±0.8x10 5 FU vs 2.88±0.52x10 5 FU in blood donors, p < 0.001, AOPP 115.43±64.54 mmol/l vs 69.07±35.83 mmol/l in blood donors, p < 0.001) and even more in dialyzed patients (AGEs 1.03±24x10 6 FU, p <0.001 vs blood donors and diabetics, AOPP 252.99±84.90 mmol/l, p < 0.001 vs blood donors and diabetics). We found a close correlation of AGEs with AOPP which is most pronounced in diabetics (r = 0.77) An interesting finding is the correlation of AGEs with age only in male blood donors (r = 0.47) and increased AOPP levels in male blood donors in comparison to females (78.60±44.01 mmol/l vs 57.20±16.31 mmol/l, p < 0.05). Both methods are fast, simple, cheap and time saving. They require, however, necessary equipment. Assessment of AGEs and AOPP as markers of damage in various diseases can be used in clinical practice.

        Key words: oxidative stress, carbonyl stress, advanced glycation end products (AGEs), advanced oxidation protein products (AOPP), spectrophotometry, spectrofluorimetry.