Assessment of Urinary Periostin Level as a Predictor of Nephropathy in Patients with Type 2 Diabetes Mellitus

Abstract

Background Periostin, originally identified in osteoblasts, functions as a cell adhesion molecule for pre-osteoblasts. It is categorized as a soluble extracellular matrix protein of 836 amino acids in length. Periostin is not observed in adult kidneys under normal conditions. It was prominently expressed in tubulointerstitial areas during renal injury and its urinary level indicates the loss of renal tubular cells
in response to diverse renal injuries. Presently, information regarding the role of periostin in chronic kidney diseases remains scarce. This study aims to clarify the potential role of urinary periostin as a predictor of nephropathy in patients with type 2 diabetes mellitus and to evaluate its relation to clinical and laboratory parameters. Methods: This study was carried out on 60 type 2 diabetic patients, divided according to urinary albumin/creatinine ratio into 20 with normoalbuminuria, 20 with microalbuminuria and 20 with macroalbuminuria. Also, 20 healthy subjects were included as a control group. Urinary periostin level, glycosylated hemoglobin, urinary albumin/creatinine ratio and serum creatinine were measured. Estimated glomerular filteration rate (eGFR) was calculated.
Results: The mean urinary periostin level was statistically significantly higher in patients with macroalbuminuria as compared to the control, normoalbuminuria & microalbuminuria groups. Also, the mean urinary periostin level was statistically significantly higher in patients with microalbuminuria as compared to the control & normoalbuminuria groups. Moreover, it was statistically significantly higher in normoalbuminuric group as compared to control group. Urinary periostin level was positively correlated with duration of diabetes, fasting and postprandial blood glucose levels, glycosylated hemoglobin, urinary albumin/creatinine ratio, serum creatinine, total cholesterol and triglycrides but negatively correlated with eGFR. Conclusion: An increased urinary periostin level is considered as an early predictor for deterioration of renal function in diabetic patients, suggesting that periostin can be used to identify diabetics at risk for diabetic kidney disease development. Clearly, further well-designed prospective studies are required to prove this hypothesis.