Leptin Status and some Biochemical Parameters in Type 2 Diabetic Males with Diabetic Nephropathy in Gaza Strip

Abstract

Background: diabetic nephropathy (DN) is the appearance of persistent clinical albuminuria in an individual with diabetes. Although the role of leptin hormone in obesity is well established, its status in DN stages is still unclear and controversial. Objective: To assess leptin status and some biochemical parameters in type 2 diabetic males with diabetic nephropathy in Gaza Strip Materials and Methods: Data were obtained from questionnaire interview, and biochemical analysis of blood and urine samples of 150 type 2 diabetic patients. ELISA and turbidumetric techniques were used to investigate serum leptin and urinary albumin levels respectively. Enzymatic and colorimetric techniques were used to investigate urea, creatinine and lipid profile. To study DN, 22 macroalbuminuric patients found in the 150 diabetic patients were involved. The same number of diabetic patients were selected and classified into normo- and microalbuminuric groups. The control group also included 22 non diabetics. All groups were matched for age and BMI. Results: The average age of the controls was 49.07±6.0 years whereas that of diabetic patients was 50.6±6.0 years. The educational level, family history and diet were associated with diabetes (P=0.000). About half of patients were diabetics since ≤5 years. The main self-reported complications were retinopathy, cardiovascular diseases and neuropathy. The longer the duration of diabetes, the higher the percentage of self reported complications. Body mass index (BMI) was positively associated with diabetes (P=0.038). Serum glucose was significantly higher in diabetics compared to controls (179.4±83.0 vs 85.6±14.2 mg/dl, % difference=70.8, P=0.000). Serum urea and creatinine were lower in diabetics (24.4±7.9 vs 31.5±7.8 and 0.64±0.19 vs 0.80±0.20 mg/dl, % differences=25.4 and 22.2, respectively and P=0.000). Cholesterol, triglycerides and low density lipoprotein cholesterol (LDL-C) were significantly higher in diabetics (198.3±38.8, 230±101.2 and 109.4±37.0 mg/dl) than controls (168.1±42.0, 152.2±77.8 and 68±40.1 mg/dl) with % differences of 16.5, 41.0 and 24.0 %, respectively and P=0.000). In contrast, high density lipoprotein cholesterol (HDL-C) was significantly lower in diabetics (42.9±6.3 vs. 51.5±10.3mg/dl, % difference=18.2 and P=0.000). Diabetic patients showed higher urinary albumin levels and GFR (110.7±179.2 vs 24.3±81.0 mg/g and 163.7±62.0 vs 127.1±343.80 ml/min/1.73m2, % difference=128.0 and 25.5, respectively and P=0.000). Urinary creatinine level was lower in patients (103.4±44.4 vs. 148.0±61.4 mg/dl and, % difference=35.5 and P=0.547). Normo-, micro- and macroalbuminuric patients were 79(52.5%), 49(32.6%) and 22(14.7%), respectively. Serum leptin was significantly higher in the microalbuminuric (14.6±11.7 ng/ml) and the macroalbuminuric (15.6±13.5 ng/ml) groups compared to control (5.9±4.0 ng/ml) group (P<0.05). Serum glucose, Cholesterol, triglycerides, LDL-C, urinary albumin were significantly higher in diabetic nephropathy patients than controls, In contrast, serum urea, creatinine, HDL-C and urinary creatinine were lower in diabetic nephropathy patients. For the study population there were positive significant correlation between serum leptin and BMI (r=0.410, P=0.000), duration (r=0.251, P=0.042), serum glucose (r=0.298, P=0.005), cholesterol (r=0.323, P=0.002), triglycerides (r=0.361, P=0.000), LDL-C (r=0.248, P=0.02) and urinary albumin (r=0.374, P=0.000), In contrast, leptin was negatively correlated with HDL-C (r=-0.313, P=0.001) and urinary creatinine (r=-0.256, P=0.016). Conclusions: Serum leptin hormone may consider according to the present funding new as a biomarker for progression of kidney disease in diabetic nephropathy patients.