Relationship of Serum Zinc Level with Severity of Diabetic Nephropathy

Chronic kidney disease (CKD) is an irreversible , progressive disease with high morbidity and mortality that occurs commonly in the general adult population, especially in people with diabetes and hypertension . It's defined as decreased kidney function shown by glomerular filtration rate (GFR) of less than 60 mL/min per 1·73 m2, or markers of kidney damage, or both, of at least 3 months duration, regardless of the underlying cause .

Diabetic kidney disease represents the most common cause of CKD in developed countries. Approximately 30% to 40% of diabetes mellitus (DM) subjects develop Diabetic kidney disease "DKD", and its presence significantly increases the risk for morbidity and mortality.

Zinc is an essential element and is the second most abundant divalent cation in the human body (2-4 g). It is mainly distributed in skeletal muscles (57%) and bone (29%) and acts as a cofactor for more than 300 enzymes. In addition, zinc is involved in the cellular mechanisms of proliferation, maintenance of structural integrity, and in the systemic regulation of the immune system . Zinc seems to have a potential role in kidney and body homeostasis in diabetic individuals which include stabilization of insulin hexamers and pancreatic insulin storage and improved glycemic control. Decreased zinc levels can impair insulin function and glucose metabolism, potentially worsening diabetes control and increasing the risk of kidney damage. Zinc is important for maintaining endothelial cell integrity and function. Endothelial dysfunction is a hallmark of DKD, and decreased zinc levels can exacerbate vascular complications associated with diabetes. Lower serum zinc levels have been associated with increased proteinuria, a common symptom of DKD. Proteinuria indicates kidney damage and is a predictor of disease progression. Zinc is involved in modulating the immune response. Deficiency can lead to a heightened inflammatory state, exacerbating kidney damage. Several studies underline the critical role of zinc in reducing oxidative stress levels, which is considered the common denominator of the mechanisms responsible for the progression of kidney disease. Zinc is a cofactor for various enzymes involved in heme synthesis and erythropoiesis