Curcumin alleviates diabetic nephropathy via inhibiting podocyte mesenchymal transdifferentiation and inducing autophagy in rats and MPC5 cells.

Context: Curcumin could ameliorate diabetic nephropathy (DN), but the mechanism remains unclear.Objective: The efficacy of curcumin on epithelial-to-mesenchymal transition (EMT) of podocyte and autophagy in vivo and in vitro was explored.Materials and methods: Thirty male Sprague-Dawley rats were divided into the normal, model and curcumin (300 mg/kg/d, i.g., for 8 weeks) groups. Rats received streptozotocin (50 mg/kg, i.p.) and high-fat-sugar diet to induce DN. Biochemical indicators and histomorphology of renal tissues were observed. In addition, cultured mouse podocytes (MPC5) was induced to EMT with serum from DN rats, and then exposed to curcumin (40 µM) with or without fumonisin B1, an Akt specific activator or 3BDO, the mTOR inducer. Western blot analysed the levels of EMT and autophagy associated proteins.Results: Administration of curcumin obviously reduced the levels of blood glucose, serum creatinine, urea nitrogen and urine albumen (by 28.4, 37.6, 33.5 and 22.4%, respectively), and attenuated renal histomorphological changes in DN rats. Podocytes were partially fused and autophagic vacuoles were increased in curcumin-treated rats. Furthermore, curcumin upregulated the expression of E-cadherin and LC3 proteins and downregulated the vimentin, TWIST1, p62, p-mTOR, p-Akt and P13K levels in DN rats and MPC5 cells. However, fumonisin B1 or 3BDO reversed the effects of curcumin on the expression of these proteins in cells.Discussion and conclusions: The protection against development of DN by curcumin treatment involved changes in inducing autophagy and alleviating podocyte EMT, through the PI3k/Akt/mTOR pathway, providing the scientific basis for further research and clinical applications of curcumin.

Autophagy activity and expression pattern of autophagy-related markers in the podocytes of patients with lupus nephritis: association with pathological classification.

OBJECTIVE: To identify the significance of autophagy in lupus nephritis (LN). METHODS: The number of autophagosomes in podocytes was counted and the expression of multiple molecular markers associated with autophagy was evaluated in LN specimens: in renal biopsy specimens from 90 patients with LN and 15 healthy controls, autophagosomes in podocytes were counted using transmission electron microscopy and the expression levels of four autophage related proteins including Beclin-1, microtubule-associated protein light chain 3 (LC3), autophagy-related gene 7 (Atg7), and UNC-51-like kinase 1 (ULK1) were measured using immunohistochemistry. RESULTS: The number of autophagosomes in patients with LN types III, IV, and combined V-IV type were significantly higher than in controls (p < 0.0001; p < 0.0001; p = 0.009, respectively). However, the autophagosomes numbers in patients with II and V types LN were significantly lower than controls (both p < 0.0001). Various levels of marker expression were identified, and they correlated significantly with LN pathology classifications. Moreover, the percentage of marker expression in LN types III, IV and V-IV were significantly higher than controls (p < 0.05), while that in types II and V were lower than controls, although the difference for LC3 and ULK1 was not statistically significant. CONCLUSIONS: Autophagy activity and expression pattern of autophagy-related markers in podocytes were significantly positively correlated with LN of types III, IV, and V-IV, but negatively correlated with II and V types. Therefore autophagy could be a useful predictor of LN pathology type, and be informative and helpful in the development of treatment strategies in clinical settings.

Effect of autophagy and stromal interaction molecule 1 on podocyte epithelial-mesenchymal transition in diabetic nephropathy.

AIM: We aimed to assess the effect of autophagy and stromal interaction molecule 1 (STIM1) on podocyte epithelial-mesenchymal transition in diabetic nephropathy. METHODS: The sera of 8-week-old db/db and C57BL/KsJ rats were used to culture MPC5 cells. The experiment was divided into 4 groups: MPC5 + siRNA-Scr + 10% C57BL/KsJ (Group A), MPC5 + siRNA-STIM1 + 10% C57BL/KsJ (Group B), MPC5 + siRNA-Scr + 10% db/db (Group C), and MPC5 + siRNA-STIM1 + 10% db/db (Group D). Podocyte autophagy was evaluated via immunofluorescence staining for LC3II and P62, and via Western blotting for P62 and LC3 (LC3II/LC3I). Western blotting was also used to assess the expression of TRPC6, Orai1, Beclin-1, Bcl-2, Caspase3, E-cadherin, fibronectin, and α-SMA protein. Furthermore, podocyte apoptosis was assessed via flow cytometry. RESULTS: We found that, in podocytes cultured in the serum of diabetic nephrotic rats, the autophagy level decreased, whereas the apoptosis level increased, and EMT can be advanced. However, after silencing STIM1 with siRNA, a converse outcome was noted. Furthermore, in diabetic nephropathy rats, the up-regulated expression of podocyte STIM1 can activate TRPC6 and Orai1 channels, which results in Ca2+ entry. CONCLUSIONS: We found that, in podocytes cultured in the serum of diabetic nephrotic rats, the autophagy level increased, whereas the apoptosis level decreased, and EMT can be inhibited by silencing STIM1 with siRNA.

Modified laparoscopic placement of peritoneal dialysis catheter with intra-abdominal fixation.

PURPOSE: Peritoneal dialysis (PD) is a commonly accepted method of treating end-stage renal disease (ESRD). Various laparoscopic techniques for the placement of PD catheter have been described. In this study, we developed a novel modified laparoscopic technique for PD catheter placement and evaluated the early results. METHODS: A straight Tenckhoff PD catheter was placed employing the modified technique in 39 consecutive patients with ESRD from May 2013 to April 2016. The technique is laparoscopically guided intra-abdominal fixation of the PD catheter tip at one point by using suture passer hernia forceps. Individual information including sex, age, primary disease etiology, complications, surgical duration, morbidity, mortality and catheter survival was collected and analyzed. RESULTS: The modified laparoscopic procedure was effectively performed in all patients with a mean operative time of 45 ± 7 min. No conversions from laparoscopy to open surgery of catheter placement occurred. There was one case showing early pericatheter leakage. There were no serious complications, such as bleeding, abdominal wall hernias, distal catheter cuff extrusion and infections of the exit site or tunnel during surgery or the postoperative duration. No mortality was observed in this group of patients. The 6-month follow-up study showed 100% catheter-related complication-free survival. CONCLUSIONS: Our modified laparoscopic intra-abdominal fixation technique using suture passer hernia forceps is a simple and safe method for PD catheter placement and is effective in minimizing the risk of catheter migration.