The alpha-lipoic acid decreases urinary podocalyxin excretion in type 2 diabetics by inhibiting oxidative stress in vivo

Objective: To observe the effects of Alpha-lipoic acid (ALA) on oxidative stress (OS) in vivo and urinary podocalyxin (PCX, the glomerular podocyte marker protein) excretion in type 2 diabetics and explore its possible protective mechanisms on glomerular podocytes. Methods: Thirty-six type 2 diabetics were recruited as observation group and treated with ALA on the basis of initial therapy for six months, and 30 healthy subjects were selected as control group. FBG, HbA1c, serum glutathione peroxidase (SGSH-Px), superoxide dismutase (SSOD) activity, urinary malondialdehyde (UMDA), 8-hydroxy-deoxyguanosine (U8-OHdG), albumin (UALB), creatinine (UCr) and urinary PCX (UPCX) were determined at baseline and after six months' observation. Results: Compared with the control group, the ratios of UMDA/UCr (UMCR), U8-OHdG/UCr (U8CR), UALB/UCr (UACR) and UPCX/UCr (UPCR) increased markedly, SGSH-Px and SSOD decreased significantly in the diabetics (P < 0.01); after sixth month treatment, the levels of UMCR, U8CR, UACR and UPCR reduced and SGSH-Px and SSOD increased markedly in the observation group (P < 0.05) with no significant changes in FBG and HbA1c. UPCR had positive correlation with UACR, UMCR and U8CR (r = 0.720, r = 0.661, r = 0.698, P < 0.01), and negative correlation with SGSH-Px and SSOD in the diabetics (r = 0.608, r = 0.559, P < 0.01). Conclusion: ALA can provide some protection against glomerular podocyte injury in type 2 diabetics, which may be related partly to its effects in alleviating enhanced OS and strengthening antioxidant ability in vivo. (C) 2015 Elsevier Inc. All rights reserved.