Is There A Place for Plasma Osteaopontin as Key Mediator in Patients With Diabetic Nephropathy?

Background: micro- and macro-vasculopathies, such as nephropathy and coronary artery disease (CAD), respectively, are common in diabetes and constitute the major causes of death for in these patients. Pro-inflammatory cytokines play a critical role in the pathogenesis of diabetic complications through various biochemical and cellular pathways. Osteopontin (OPN) has been identified as a key regulator of many metabolic and inflammatory diseases including obesity, diabete and  diabetic nephropathy. The aim of this study was to evaluate  plasma level of osteopontin in different stages of diabetic nephropathy in type II DM, and to correlate it with the stage of nephropathy and with other measured parameters. Patients and methods:the study was conducted on 58 patients with diabetic nephropathy as well as  15 apparently healthy subjects as a control group. Patients were classified into 2 main groups according to the level of  glycosylated hemoglobin (H_bA_1c) Group I: controlled type II DM (H_bA_1c 5.55%-7.6%). Group II: uncontrolled type II DM (H_bA_1c 7.6 %).Each group was subdivided into two subgroups (A and B) according to the presence of microalbuminuriaor macroalbuminuria (degree of nephropathy). In addition to, Group III: DM type II with end stage renal disease (serum creatinine ≥ 5mg/dl) and just starting hemodialysis (1-3 sessions Only) plasma osteopontin was measured by ELISA. Results of the study revealed significant increase of serum  osteopontin  in all studied groups
Results: compared to normal control subjects (P<0.001).There was a statistically positive correlation between serum osteopontin versus all variables in group I and II; except   HBA1C in group I, and FBS in group II. But, no statistical correlation change between serum osteopontin versus all variables in group III (P>0.05).Cut ROC curve of osteopontin levels of all cases of diabetic nephropathy indicates high validity of OPN to detect positive cases of diabetic nephropathy with accuracy of 100%, andOPN is considered a high validity test in  prediction of  end-stage renal disease (ESRD) more than prediction of microalbumnuria.  Conclusion: plasma level of osteopontin increases with the progression of diabetic nephropathy and osteopontin may be useful as a biomarker to trace disease progression as well as a potential diagnostic biomarker for the prediction of diabetic ESRD.