Effect of lipoic acid on urinary microalbumin and inflammation in patients with diabetic nephropathy at different stages

Abstract

Objective To investigate the effect of lipoic acid on urinary microalbumin and inflammation in patients with diabetic nephropathy at different stages. Methods Ninety patients with type 2 diabetes who were hospitalized at the Department of Endocrinology, Meizhou People's Hospital from July 2015 to December 2017 were selected, and they were divided into three groups according to 24-hour urinary albumin excretion rate (UAER): normal albuminuria group (NA group, UAER<30 mg/24 h), microalbuminuria group (MA group, 30 mg/24 h≤UAER<300 mg/24 h), and clinical nephropathy group (CN group, UAER≥300 mg/24 h). At the same time, we randomly selected 30 patients who underwent physical examination as a normal control group (NC group). Then, the three groups of diabetes patients were randomly and equally divided into an observation group and a control group using a random number table. The control group was given conventional treatment. The observation group was given 0.45 g lipoic acid for injection plus 0.9% sodium chloride injection 250 mL by slow intravenous infusion, once a day for 2 weeks. The changes of UAER, serum creatinine (SCr), blood glucose, hs-CRP, and TNF-α levels were observed. Results The levels of serum hs-CRP and TNF-α in the three groups of patients with type 2 diabetic nephropathy were significantly higher than those in the NC group [(5.98±1.54) mg/L, (6.49±1.84) mg/L, (7.02±1.75) mg/L vs (2.95±0.86) mg/L, F=15.63, P<0.01; (17.19±5.05) ng/L, (19.61±5.42) ng/L, (20.25±6.23) ng/L vs (10.24±3.16) ng/L, F=25.22, P<0.01]; however, there was no significant difference among the three groups of patients with type 2 diabetic nephropathy. The levels of hs-CRP, TNF-α, SCr, and UAER were decreased significantly after lipoic acid treatment in the observation groups than in the control groups [(5.01±0.93) mg/L vs (3.89±0.72) mg/L, (5.51±1.23) mg/L vs (4.25±0.88) mg/L, (6.15±1.32) mg/L vs (4.78±1.01) mg/L, t=3.689, 3.227, 3.192, P<0.05; (15.59±4.19) ng/L vs (12.04±3.45) ng/L, (18.02±4.42) ng/L vs (14.43±4.22) ng/L, (18.67±4.88) ng/L vs (15.09±4.47) ng/L, t=2.526, 2.275, 2.095, P<0.05; (83.5±9.4) μmol/L vs (67.3±6.2) μmol/L, (85.6±16.0) μmol/L vs (61.3±16.7) μmol/L, (98.5±20.4) μmol/L vs (69.4±16.8) μmol/L, t=5.572, 4.069, 4.265, P<0.05; (16.5±7.4) mg/24 h vs (13.3±6.2) mg/24 h, (145.6±66.0) mg/24 h vs (106.3±56.7) mg/24 h, (805.5±166.4) mg/24 h vs (612.3±110.8) mg/24 h, t=5.597, 2.051, 3.742, P<0.05]. Conclusion The inflammatory reaction exists in type 2 diabetic nephropathy patients. Lipoic acid can protect the kidney by improving the inflammatory state of type 2 diabetic nephropathy, reducing urinary microalbumin excretion, and lowering serum creatinine levels. Key words: Lipoic acid; Diabetic nephropathy; Inflammatory factors; Hypersensitive C-reactive protein; Tumor necrosis factor alpha