Diagnostic Value of Serum Cathepsin S and Chromogranin A in DKD

1. Evulate the diagnostic value of serum cathepsin S and chromogranin A for Diabetic kidney disease. 2. To correlate the levels of serum Cathepsin S and chromogranin A with HbA1c and eGFR in type 2 diabetic patients based on urinary Albumin- Creatinine Ratio.

Diabetic nephropathy (DN) is a common and serious complication of diabetes and has been shown to be a major cause of end-stage renal disease (ESRD), requiring costly renal replacement therapy in the form of dialysis or transplantation . It is appreciated that up to 40% of patients with type 1 and type 2 diabetes mellitus (DM) present DN . Early detection and appropriate treatment are essential to prevent disability and death. Cathepsin S (Cat-S) was a secreted cysteine proteolytic enzyme that is mainly expressed in macrophages. Macrophages undergoing chemotaxis adhere to the basement membrane of blood vessels and secrete Cat-S, and the secreted Cat-S was involved in hydrolysis of elastin, laminin, collagen and other extracellular matrix components, causing vascular damage . So, Cathepsin S(Cat-S), a novel non-invasive diagnostic marker mediates vascular endothelial dysfunction. In recent years, studies have shown that up regulation of Cat-S was associated with the development of IgA nephropathy, lupus nephritis, insulin resistance, diabetes and other renal diseases. Chromogranin A (CgA) is the main member of the chromogranin family and is an acidic glycoprotein consisting of 439 amino acids with an approximate molecular mass of 48 kDa. CgA is used as a diagnostic marker of neuroendocrine tumors(6). The kidney is the main site for the removal of CgA, and it is retained in serum with declining renal function. In patients with renal failure, serum CgA increases much more than creatinine and the other studied low-MW proteins.