Peculiarities of purine metabolism at the different forms of gouty arthritis and nephropathy

Abstract

Objective — to evaluate parameters of purine metabolism in case of complex variants of articular and renal syndromes in patients with gout.Materials and methods. Examinations involved 105 patients with primary gout, from them 92 % of men and 8 % of women aged between 26 to 76 years (51 years on average), and women were 8 years older. The average duration of the disease was 12 years. The first sign of gout was the joint crisis in 91 % of the patients, and renal colic in the rest of cases The ratio of the frequency of intermittent and chronic forms of arthritis was 2 : 1, the latent type of nephropathy occur-red in 66 % of cases, urolithiasis in 34 %, and the ratio of stages I, II, III and IV of chronic kidney disease was 4 : 2 : 1 : 1. The levels of purine metabolism factors were investigated: levels of uric acid in blood and urine (AUb and AUu), and serum levels of oxypurinol — OP, adenine — Ad, guanine — Gu, xanthine — Xa, hypoxanthine — HX, xanthine oxidase — XO, xanthine deaminase — XD, adenosine deaminase — AD, 5 nucleotidase — 5N, molybdenum — Mo, lead — Pb. The renal clearance tests (Cau, Cop, Cau/Cop) were performed. A spectrophotometer SF46 (Russia), an Olympus-AU 640 (Japan) bioanalyzer and an atomic absorption spectrometer with an SolAAr-Mk2-MOZe electrograph atomizer (UK) were used. Patients were examined during absence of arthritis exacerbation.Results and discussion. In cases of gout, the AUb indicators were (514.6 ± 13.65) µmol/l, AUu — (5.0 ± 0.23) µmol/l, Cau — (6.8 ± 0.32) ml/min, OP — (105.9 ± 6.62) µmol/l, Cop — (16.9 ± 0.62) ml/min, Ad — (136.8 ± 3.66) u. e., Gu — (183.7 ± 4.45) u. e., Xa — (148.2 ± 2.72) u. e., HXa — (7.1 ± 0.41) u. e., XO — (7.1 ± 0.41) nmol/ml ⋅ min, XD — (7.7 ± 0.45) nmol/ml ⋅ min, AD — (14,9 ± 2,04) nmol/ml ⋅ min, 5N — (6.0 ± 0.10) nmol/ml ⋅ min, Mo — (1.6 ± 0,08) µg/l, Pb — (63.4 ± 2.77) µg/l. The ratio of Cau to the glomerular filtration rate was (9.7 ± 0.74) %, and Cau/Cop was (53.3 ± 4.94) %. In comparison with the control group of practically healthy people, a significant increase in the parameters of AUb by 90 %, OP — in 10.7 times, XO — in 2.0 times, AD — in 9.3 times and Pb — by 59 % was observed. But the parameters of Cau were decreased by 72 % and Cop — by 15 %, which was established in 100, 93, 38, 98, 53, 100 and 59 % cases of observations respectively. The integral changes in the parameters were enhancing with the increase of the disease duration and were associated with the patients’ gender (men had higher levels of uricemia and urticaria), depended on the form of joint and kidney syndromes, the presence of peripheral and bone tophi, the stage of chronic kidney disease. They determine bone-destructive articular and structural kidney lesions and the character of the urinary syndrome. With this, the negative prognostic signs for the severity of bone-destructive changes in cases of gouty arthritis included blood levels of purine bases Ad > 175 u. e., Gu > 230 u. e., Xa > 175 u. e., HXa > 200 u. e. The blood indices of Pb > 90 µg/l are recommended for prognosing of the kidney function reduction.Conclusions. It has been established that various components of purine metabolism in patients with gout are involved in the pathogenetic development of joint and renal syndromes, the high parameters of purine bases and level of plumbemia have a high prognostic value.