Serum fibroblast growth factor 21 and lipocalin as early biomarkers of nephropathy in TYPE 2 diabetes mellitus and their relationship with adipocytokines

Type 2 Diabetes Mellitus (Type 2DM) is the most common metabolic disease worldwide. One of the major complications of this disease is diabetic nephropathy (DN) which is the leading cause of end-stage renal disease in the Western world. Microalbuminuria (MAU) is the earliest and most widely used laboratory index of DN and is independently associated with cardiovascular risk in diabetic patients. Although MAU remains an indispensable tool for monitoring risk stratification and disease progression in DN, several factors have questioned its ability to predict the disease. Our aim in this study is to investigate serum fibroblast growth factor-21 (fibroblast growth factor-21-FGF-21) and neutrophil gelatinase-associated lipocalin (neutrophil gelatinase associated lipocalin-NGAL) levels in patients with Type 2DM, with (n = 40) and without MAU (n = 40). The role of adipocytokines such as adiponectin, leptin and plasminogen activator inhibitor Type 1(PAI-1) in the early diagnosis and follow-up of renal damage are also investigated. Adiponectin, leptin and PAI-1 were analysed with Multiplex Assay Systems which allowed smaller sample volume and faster measurement, while FGF-21, NGAL and cystatin C levels were measured with ELISA. FGF-21 and NGAL levels were significantly higher and PAI-1 levels were significantly lower in patients with MAU. In general, there was a (-) correlation between cystatin C and PAI-1, and (+) correlation between adiponectin and leptin. It was concluded that FGF-21 and NGAL may be clinically important new biomarkers in DN related with Type2DM and further studies on PAI-1 should be performed. Studies with large cohorts and different DN stages will help us to understand the pathophysiology of renal complications in patients with Type 2DM.