Urinary cyclophilin A as an early marker of chronic kidney disease with underlying type 2 diabetes

Cyclophilin A (CypA) is a novel renal inflammation biomarker, with levels altered in various diseases, particularly in patients with diabetes mellitus (DM) and kidney damage. This study aimed to investigate the correlation between urinary cyclophilin A (uCypA) and chronic kidney disease (CKD) conditions with and without type 2 diabetes mellitus (T2DM) using an in-house enzyme-linked immunoassay (ELISA) method. A uCypA strip-test prototype was also developed. An indirect ELISA was performed to determine the uCypA levels. A 0.48 µg/mL uCypA cutoff differentiated healthy patients from those with early-stage CKD (stages I and II). The uCypA levels were significantly increased in patients with progression of renal deterioration, especially in the T2DM with late-stage CKD group, compared to the control group. Fasting blood sugar (FBS), estimated glomerular filtration rate (eGFR), albumin/creatinine ratio, and metformin use were associated with uCypA levels. Multinomial logistic regression analysis revealed an association between uCypA levels and T2DM diagnosed for over five years and early-stage CKD. This finding shows that uCypA could be used as a biomarker for distinguishing early-stage CKD as well as T2DM complications, which is beneficial for patients to be aware of their health status and change their behavior to slow kidney deterioration.