Plasma sKL and Nrf2 Levels in Patients with Calcium Oxalate Stones

Abstract Objective To investigate the relationship between the plasma levels of sKL and Nrf2 and calcium oxalate calculi.Methods The clinical data of 135 patients with calcium oxalate calculi treated in the Department of Urology of the Second Affiliated Hospital of Xinjiang Medical University from February 2019 to December 2022 (the stone group) and 125 healthy persons who underwent physical examination in the same period (the healthy control group) were collected. The levels of sKL and Nrf2 were measured by ELISA. A correlation test was used to analyze the risk factors for calcium oxalate stones. Logistic regression analysis was used to analyze the risk factors for calcium oxalate stones, and an ROC curve was used to evaluate the sensitivity and specificity of sKL and Nrf2 in predicting urinary calculi.Results Compared with the healthy control group, the plasma sKL level in the stone group was decreased (111.53 ± 27.89 vs. 130.68 ± 32.51), and the plasma Nrf2 level was increased (300.74 ± 114.31 vs. 246.74 ± 108.22). There was no significant difference in the distribution of age and sex between the healthy control group and the stone group, but there were significant differences in plasma levels of WBC, NEUT, CRP, BUN, BUA, and SCr, BMI and eating habits. The results of the correlation test showed that the level of plasma Nrf2 was positively correlated with SCr (r = 0.181, P < 0.05) and NEUT (r = 0.144 P < 0.05). Plasma sKL was not significantly correlated with Nrf2 (r = 0.047, P > 0.05), WBC (r = 0.108, P > 0.05), CRP (r=-0.022, P > 0.05), BUN (r=-0.115, P > 0.05), BUA (r=-0.139, P > 0.05), SCr (r = 0.049, P > 0.05), or NEUT (r = 0.027, P > 0.05). Plasma Nrf2 was not significantly correlated with WBC (r = 0.097, P > 0.05), CRP (r = 0.045, P > 0.05), BUN (r = 0.122, P > 0.05), or BUA (r = 0.122, P > 0.05).=0.078, P > 0.05). Logistic regression showed that elevated plasma sKL (OR = 0.978, 95% CI: 0.969 ~ 0.988, P < 0.05) was a protective factor for the occurrence of calcium oxalate stones. BMI (OR = 1.122, 95% CI: 1.045 ~ 1.206, P < 0.05), dietary habit score (OR = 1.571, 95% CI: 1.221 ~ 2.020, P < 0.05), WBC (OR = 1.551, 95% CI: 1.423 ~ 1.424, P < 0.05), NEUT (OR = 1.539, 95% CI: 1.391 ~ 1.395, P < 0.05) and CRP (OR = 1.118, 95% CI: 1.066 ~ 1.098, P < 0.05) were risk factors for the occurrence of calcium oxalate stones.Conclusion Plasma sKL levels were decreased and Nrf2 levels were increased in patients with calcium oxalate calculi. Plasma sKL may play an antioxidant role in the pathogenesis of calcium oxalate stones through the Nrf2 antioxidant pathway.