Wei Shi

Podocyte injury is a common hallmark of chronic kidney disease (CKD). The podocin-nephrin complex localized in lipid rafts of podocyte is vital to reduce podocyte injury and proteinuria, however, the mechanism underlying its localization remains unclear. This study uncovers an important role of Flot2 in stabilizing the podocin-nephrin complex localized in lipid rafts. We first confirmed that Flot2 was expressed in podocyte and demenstrated that podocyte-specific Flot2 deletion worsen albuminuria, podocyte injury and glomerular pathology in LPS/ADR-induced nephropathy mouse models. Meanwhile, podocyte injury, albuminuria and pathologic aberrance were prevented in podocyte-specific Flot2 overexpression transgenic mice when challenged with LPS or ADR. Further found that Flot2 was vital to recruit podocin and nephrin into rafts and ameliorated podocyte injury. Flot2 and podocin directly interacted with each other via their SPFH domain. Meanwhile, we also showed that Flot-2 is a direct target of Krüppel-like factor (KLF15). Importanly, we observed that Flot2 was downregulated in renal biopsies from patients with podocytopathies and its expression negatively correlated with proteinuria and positively correlated with eGFR, indicating that Flot2 may be a novel therapeutic target for proteinuric kidney disease.

Autophagy is important for maintaining normal physiological functions and podocyte cell homeostasis. Amino acid signaling is an important upstream signaling pathway for autophagy regulation. However, the function and the associated mechanism of amino acid signaling in podocyte autophagy is unclear. The present study used normal culture medium and amino acid deprivation medium to culture podocytes in vitro. Multiple methods were utilized to detect autophagic activity including western blot analysis to measure the levels of microtubule‑associated protein 1 light chain 3 (LC3) II and beclin1, reverse transcription‑quantitative polymerase chain reaction was performed to evaluate the levels of LC3 mRNA and transmission electron microscopy was conducted to observe autophagosomes. In addition, tandem green fluorescent protein (GFP)‑monomeric red fluorescent protein (mRFP)‑LC3 adenoviruses were employed to transduce podocytes to observe autophagic flux. Furthermore, the present study examined the effects of amino acid signaling on mammalian target of rapamycin (mTOR) activity and the nuclear translocation of transcription factor EB (TFEB), a core regulator of autophagy, using western blotting and immunofluorescence. The results revealed that amino acid starvation promoted the expression of LC3II and beclin1, and increased the number of autophagosomes and autolysosomes. Amino acid starvation inhibited mTOR activity, and promoted nuclear translocation and TFEB activity. Inhibition of TFEB blocked amino acid starvation‑induced autophagy. These results indicated that amino acid starvation stimulated podocyte autophagy, and thus suggested that mTOR suppression and TFEB activation may mediate amino acid starvation‑induced autophagy in podocytes.

We present the case of a 42‐year‐old female patient who attempted suicide by taking approximately 100 tablets of metformin (500 mg). Laboratory tests revealed severe lactic acidosis with lactate levels of 24 mmol/L and pH of 7.09. The patient was treated with high‐volume continuous venovenous hemodiafiltration (CVVH) and resin‐sorbent hemoperfusion. Metformin concentrations were measured by high‐performance liquid chromatography during CVVH and hemoperfusion treatment. Before extracorporeal treatment, the plasma metformin concentration was 208.5 mg/L. After CVVH treatment for 24 h, the plasma metformin concentration had decreased to 13.9 mg/L. Resin‐based sorbent hemoperfusion plus CVVH treatment had reduced the metformin plasma concentration by 61.8% after 3 h. After 7 days, the patient's laboratory tests and clinical syndrome were improved, and she was discharged from hospital. We provide evidence that CVVH plus hemoperfusion is effective in eliminating metformins and metabolic products.

Tacrolimus inhibits hepatitis B virus entry into hepatocytes through targeting the HBV receptor, sodium taurocholate cotransporting polypeptide. This study was performed to evaluate the efficacy and safety of Tacrolimus combined with entecavir antiviral therapy for HBV-associated glomerulonephritis patients with biopsy-proven membranous nephropathy. A cohort of 42 patients was enrolled in this retrospective study. Twenty-three patients received Tacrolimus (0.05 mg/kg/day) in combination entecavir over 24 weeks, whereas the other 19 patients only received entecavir monotherapy. The probability of proteinuria remission in the Tacrolimus+entecavir group was 69 and 87% after 12 and 24 weeks, whereas was only 26 and 42%, respectively, in the entecavir group. The mean time to partial or complete remission was 18.6 weeks in the Tacrolimus+entecavir group and 34.3 weeks in the entecavir group (P<0.001). A decrease in the HBV DNA titer was observed in all patients with active HBV replication. None of the HBV carriers in the Tacrolimus+entecavir group showed evidence of HBV reactivation. The serum creatinine and alanine aminotransferase levels remained stable in both groups. The Tacrolimus target trough concentration was 5-10 ng/mL. Tacrolimus combined with entecavir rapidly and effectively induced remission of HBV-GN in Chinese adults. Furthermore, Tacrolimus may have a synergistic antiviral effect with entecavir.

The time-averaged serum potassium was more comprehensive to reflect the all-time changes of serum potassium levels during peritoneal dialysis (PD). However, the association of fluctuation of time-averaged serum potassium level with long-time survival of PD patients remains unknown. In this retrospective study, we included 357 incident PD patients in 2 centers from January 1, 2007 to October 31, 2012 with follow-up through October 31, 2014. Our data demonstrated that it was the lower time-averaged serum potassium level rather than baseline of serum potassium level that was associated with high risk of death. Patients with higher standard deviation (SD) had significantly poorer all-cause (p = 0.016) and cardiovascular mortality (p = 0.041). Among the patients with time-averaged serum potassium levels below 4.0 mEq/L, a lower mean value was more important than its SD to predict death risk. In contrast, the patients with time-averaged serum potassium levels above 4.0 mEq/L, those with serum potassium SD < 0.54 mEq/L, exhibited a higher 3-year and 5-year survival rate for both all-cause and cardiovascular mortality compared to the control groups. Our data clearly suggested both time-averaged serum potassium and its fluctuation contributed disproportionately to the high death risk in PD patients.

The Hakka are a sub-ethnicity with unique diet customs in South China. This study investigated hyperphosphatemia in hemodialysis patients in relation to the current Hakka dietary customs and explored health education patterns for hyperphosphatemia control. Two continuous cross-sectional surveys were conducted among the local patients on dialysis. After the first survey, the patients with hyperphosphatemia were semi-randomized into regular (group 1) and individual (group 2) education groups. Regular health education was conducted for both groups. In group 2, the awareness of health knowledge and dietary customs was investigated using a self-designed questionnaire. Based on the questionnaire, individual dietary guidance was given. The second survey was performed after 3 months. In the first survey, a high-phosphorus diet was found in all 46 patients with 43 (93.5%) diagnosed with hyperphosphatemia. In group 1 and group 2, 15 patients and 25 patients completed the two surveys, respectively. In group 1, no patient changed their dietary habits; however, in group 2, some patients did. The level of serum inorganic phosphorus in group 1 increased significantly. In group 2, the data remained stable; the awareness rate of chronic kidney disease–mineral and bone disorder (CKD–MBD) increased, and six patients with good compliance showed decreased serum inorganic phosphorus (p = 0.046). High-phosphorus dietary customs and low CKD–MBD knowledge awareness are important reasons for the difficulty in hyperphosphatemia control of patients on dialysis in the Hakka region. Individual health education led by medical staff might be helpful in hyperphosphatemia control, but the pattern still needs further exploration.

Necrostatin-1 (Nec-1) inhibits necroptosis and is usually regarded as having no effect on other cell deaths. Here, this study explored whether the addition of Nec-1 has an effect on cell death induced by simulated ischemia injury in rat tubular cell line NRK-52E. In addition, we also investigated the mechanism of Nec-1 attenuates cell death in this renal ischemia model. The NRK-52E cells were incubated with TNF-α + antimycinA (TA) for 24 h with or without Nec-1. Cell death was observed under fluorescent microscope and quantified by flow cytometry. Cell viabilities were detected by MTT assay. The protein expression of dynamin-related protein 1 (Drp1) was detected by Western blotting and immunofluorescence assay. Increased cell death in simulated ischemia injury of NRK-52E cells were markedly attenuated in the Nec-1 pretreated ischemia injury group. Meanwhile, cell viability was significantly improved after using Nec-1. In addition, we also observed that the protein expression of Drp1, a mediator of mitochondrial fission, was significantly increased in simulated ischemia injury group. Increased Drp1 expression in the ischemia injury group can be abolished by Nec-1 or Drp1-knock down, accompanied with decreased cell death and improved cell viabilities. These results suggest that Nec-1 may inhibit cell death induced by simulated ischemia injury in the rat tubular cell line NRK-52E through decreased Drp1 expression.