Gclc as a Marker for Injured Distal Nephron in Ischemia-Reperfusion Induced Acute Kidney Injury.

Purpose: The distal nephron of kidney plays a pivotal role in advancing acute kidney injury (AKI). Understanding the role of distal nephrons in AKI and identifying markers of injured distal nephrons are critical to comprehending the mechanism of renal injury and identifying novel therapeutic targets. Methods: We analyzed single-cell RNA sequencing (scRNA-seq) data from mice with AKI induced by ischemia-reperfusion (IR), unilateral ureteral obstruction (UUO), cisplatin (CP), sodium oxalate (SO) and lipopolysaccharide (LPS). Additionally, we analyzed renal transcriptomics samples for AKI. Subsequently, we validated the effectiveness of targeting the biomarker Gclc in vitro and in vivo through metabolomics and immunofluorescence. Results: The LOH-Inj and DCT-Inj subtypes were identified through scRNA-seq. Compared to normal distal nephrons, the injured distal nephrons exhibited higher levels of ferroptosis, pro-inflammation, and fibrosis. The expression of ferroptosis-related gene Gclc were high in various AKI models. Furthermore, Gclc was exclusively expressed in the distal nephron and upregulated in the injury subtype. To confirm our findings, we suppressed GCLC expression in the kidneys, resulting to aggravated IR-induced AKI. Inhibition of Gclc promoted damage to primarily renal tubular epithelial cells by promoting inflammatory infiltration, inhibiting glutathione metabolism and exacerbating oxidative stress. Conclusion: Our research findings suggest that Gclc is a potential marker for injured distal nephron.

The probiotic Lactobacillus casei Zhang-mediated correction of gut dysbiosis ameliorates peritoneal fibrosis by suppressing macrophage-related inflammation via the butyrate/PPAR-γ/NF-κB pathway.

Peritoneal fibrosis is a complication of long-term peritoneal dialysis (PD) that restricts its clinical application for the treatment of end-stage renal disease. Lactobacillus casei Zhang (LCZ), a probiotic strain isolated from traditional fermented koumiss, exhibits health benefits such as anti-inflammatory and antioxidative effects, improvement of insulin resistance and mitigation of renal injury. However, whether LCZ can prevent peritoneal fibrosis remains unknown. Here, we assessed the effects of LCZ in a mouse model of PD-induced peritoneal fibrosis. Our results showed that the administration of LCZ significantly ameliorated peritoneal fibrosis in experimental mice. Macrophage infiltration, inflammatory M1 polarization and inflammatory cytokines in peritoneal dialysis effluents were effectively reduced by LCZ. Meanwhile, LCZ corrected gut dysbiosis and enriched beneficial bacteria that produce short-chain fatty acids, specifically Dubosiella, Lachnospiraceae, Parvibacter, and Butyricicoccus. Correspondingly, the local butyrate level in peritoneal dialysis effluents was significantly elevated by LCZ. Mechanistically, we found activation of PPARγ and inhibition of the NF-κB pathway in LCZ-treated mice, an observation that was replicated in a butyrate-treated macrophage cell line. In conclusion, our study suggests that LCZ is beneficial for preventing PD-induced peritoneal fibrosis through modulating the gut microbiota, enhancing butyrate production, activating PPARγ, and suppressing NF-κB-mediated inflammation.

Effects of probiotics on non-alcoholic fatty liver disease: a review of human clinical trials.

Non-alcoholic fatty liver disease (NAFLD) is a global public health issue, of which the prevalence is about 25% worldwide. The incidence of NAFLD is increasing in patients with obesity, type 2 diabetes (T2DM) and the metabolic syndrome. The crosstalk between gut microbiota and metabolism-related diseases has been raised great concern. Patients with NAPLD were observed with disruption of gut microbiota. Several researches showed that gut microbiota was the determination in the progression of NAFLD by the experiments using fecal microbiota transplants. The application of probiotics, as one of the most important strategies for the regulation of gut microbiota disorder, have been explored whether it is beneficial to gut-related diseases of intestine-distal organs. Some probiotics were showed to improve the liver parameters and phenotype in patients with NAFLD. The oral intake of them might become the effective management for the prevention and treatment of NAFLD. In this review, we summarized the human clinical trials focusing on the effects of probiotics on NAFLD to give some evidential reference for the administration of NAFLD.

Deep Sea Water Inhibited Pancreatic ß-Cell Apoptosis and Regulated Glucose Homeostasis by Affecting Lipid Metabolism in Db/Db Mice.

Purpose: Deep sea water (DSW) is a natural resource rich in minerals, which participates in biological processes such as energy metabolism, regulates serum glucose and lipids levels, and has a certain protective effect on endocrine and metabolism-related diseases. Studies have shown that the improvement of glucose tolerance in diabetic mice by DSW may be associated with the protective effect on the structure and function of pancreatic islets, and the specific mechanism is still unclear. Other studies have shown that long-term exposure to high concentrations of fatty acids can lead to apoptosis and dysfunction of pancreatic ß-cell, increasing the risk of type 2 diabetes mellitus (T2DM). Down-regulation of plasma fatty acid levels may reduce pancreatic ß-cell dysfunction, thereby improving glucose homeostasis. Understanding the specific mechanism of DSW regulating blood glucose is of great significance for its clinical application. Methods: In the present study we used db/db mice as a T2DM model and treated mice with deep ocean mineral concentration (DOMC, a commercial product of DSW) for 4 and 12 weeks. Basic information, serum biochemical indicators, and pathological tissues were gathered for exploration. Results: The db/db mice treated with 4 weeks' DOMC (db/db+DOMC) showed decreased plasma cholesterol and triglyceride levels. Tests implied that in adipose tissues, the db/db+DOMC group's lipolysis process was inhibited, and the ß-fatty acid oxidation process was promoted. Besides, DOMC reduced lipogenesis and encouraged ß-oxidation in the liver, as a result, improved fatty liver in db/db mice. Further measurements showed DOMC improved glucose homeostasis slightly in db/db animals after a 12-week treatment by preventing pancreatic ß-cell apoptosis. Conclusion: DOMC inhibited pancreatic ß-cell apoptosis and regulated glucose homeostasis in db/db mice by lowering the lipid levels via regulation of fatty acid ß-oxidation, lipolysis, and lipogenesis processes.

Identification of Major Risk Factors and Non-linear Effects to the Development of Left Ventricular Hypertrophy in Chronic Kidney Disease by Constructing and Validation of Nomograms.

Background: Left ventricular hypertrophy (LVH) is a common cardiovascular complication among chronic kidney disease (CKD) patients. The present study aimed to identify major independent risk factors and determine their contribution and relationship to LVH development. Methods: Clinical and echocardiographic data of 2002 pre-dialytic CKD patients were retrospectively collected. Independent risk factors for LVH were identified using univariable and multivariable logistic regression. Nomograms together with restricted cubic splines method were employed to explore the effect size and possible non-linear relationship with regard to LVH. A simplified predictive model was constructed and its predictive ability was validated to demonstrate to which extent the identified risk factors accounted for LVH risk. Results: Multivariable logistic regression identified age, body mass index (BMI), systolic blood pressure (SBP), eGFR and hemoglobin as independent influencing factors for LVH. Nomogram revealed BMI, SBP and hemoglobin concentration as the most important risk factors. Impaired renal function only showed obvious risk for LVH when eGFR declined below 30 ml/min/1.73 m2. Significant threshold effects existed for blood pressure and obesity that the risks for LVH doubled when SBP exceeded 160 mmHg or BMI exceeded 30 kg/m2. The predictive model constructed performed well on both the training and validation cohort using calibration curve, ROC curve and AUC value, with AUC above 0.80 for both the training cohort and the validation cohort. Conclusions: With the help of nomogram model, we identified five independent factors that explain a large proportion of LVH risk in CKD patients. Among them, major contribution to LVH development was resulted from comorbidities and complications of CKD (hypertension, anemia, obesity) rather than eGFR reduction per se. Non-linear relationship and threshold relationship between eGFR, blood pressure, obesity and LVH risk were also identified.

Blocking connexin 43 and its promotion of ATP release from renal tubular epithelial cells ameliorates renal fibrosis.

Whether metabolites derived from injured renal tubular epithelial cells (TECs) participate in renal fibrosis is poorly explored. After TEC injury, various metabolites are released and among the most potent is adenosine triphosphate (ATP), which is released via ATP-permeable channels. In these hemichannels, connexin 43 (Cx43) is the most common member. However, its role in renal interstitial fibrosis (RIF) has not been fully examined. We analyzed renal samples from patients with obstructive nephropathy and mice with unilateral ureteral obstruction (UUO). Cx43-KSP mice were generated to deplete Cx43 in TECs. Through transcriptomics, metabolomics, and single-cell sequencing multi-omics analysis, the relationship among tubular Cx43, ATP, and macrophages in renal fibrosis was explored. The expression of Cx43 in TECs was upregulated in both patients and mice with obstructive nephropathy. Knockdown of Cx43 in TECs or using Cx43-specific inhibitors reduced UUO-induced inflammation and fibrosis in mice. Single-cell RNA sequencing showed that ATP specific receptors, including P2rx4 and P2rx7, were distributed mainly on macrophages. We found that P2rx4- or P2rx7-positive macrophages underwent pyroptosis after UUO, and in vitro ATP directly induced pyroptosis by macrophages. The administration of P2 receptor or P2X7 receptor blockers to UUO mice inhibited macrophage pyroptosis and demonstrated a similar degree of renoprotection as Cx43 genetic depletion. Further, we found that GAP 26 (a Cx43 hemichannel inhibitor) and A-839977 (an inhibitor of the pyroptosis receptor) alleviated UUO-induced fibrosis, while BzATP (the agonist of pyroptosis receptor) exacerbated fibrosis. Single-cell sequencing demonstrated that the pyroptotic macrophages upregulated the release of CXCL10, which activated intrarenal fibroblasts. Cx43 mediates the release of ATP from TECs during renal injury, inducing peritubular macrophage pyroptosis, which subsequently leads to the release of CXCL10 and activation of intrarenal fibroblasts and acceleration of renal fibrosis.

The probiotic L. casei Zhang slows the progression of acute and chronic kidney disease.

The relationship between gut microbial dysbiosis and acute or chronic kidney disease (CKD) is still unclear. Here, we show that oral administration of the probiotic Lactobacillus casei Zhang (L. casei Zhang) corrected bilateral renal ischemia-reperfusion (I/R)-induced gut microbial dysbiosis, alleviated kidney injury, and delayed its progression to CKD in mice. L. casei Zhang elevated the levels of short-chain fatty acids (SCFAs) and nicotinamide in the serum and kidney, resulting in reduced renal inflammation and damage to renal tubular epithelial cells. We also performed a 1-year phase 1 placebo-controlled study of oral L. casei Zhang use (Chinese clinical trial registry, ChiCTR-INR-17013952), which was well tolerated and slowed the decline of kidney function in individuals with stage 3-5 CKD. These results show that oral administration of L. casei Zhang, by altering SCFAs and nicotinamide metabolism, is a potential therapy to mitigate kidney injury and slow the progression of renal decline.