Natural intestinal metabolite xylitol reduces BRD4 levels to mitigate renal fibrosis.

Renal fibrosis is a typical pathological change from chronic kidney disease (CKD) to end-stage renal failure, which presents significant challenges in prevention and treatment. The progression of renal fibrosis is closely associated with the "gut-kidney axis," therefore, although clinical intervention to modulate the "gut-kidney axis" imbalance associated with renal fibrosis brings hope for its treatment. In this study, we first identified the close relationship between renal fibrosis development and the intestinal microenvironment through fecal microtransplantation and non-absorbable antibiotics experiments. Then, we analyzed the specific connection between the intestinal microenvironment and renal fibrosis using microbiomics and metabolomics, screening for the differential intestinal metabolite. Potential metabolite action targets were initially identified through network simulation of molecular docking and further verified by molecular biology experiment. We used flow cytometry, TUNEL apoptosis staining, immunohistochemistry, and Western blotting to assess renal injury and fibrosis extent, exploring the potential role of gut microbial metabolite in renal fibrosis development. We discovered that CKD-triggered alterations in the intestinal microenvironment exacerbate renal injury and fibrosis. When metabolomic analysis was combined with experiments in vivo, we found that the differential metabolite xylitol delays renal injury and fibrosis development. We further validated this hypothesis at the cellular level. Mechanically, bromodomain-containing protein 4 (BRD4) protein exhibits strong binding with xylitol, and xylitol alleviates renal fibrosis by inhibiting BRD4 and its downstream transforming growth factor-ß (TGF-ß) pathway. In summary, our findings suggest that the natural intestinal metabolite xylitol mitigates renal fibrosis by inhibiting the BRD4-regulated TGF-ß pathway.

The role of regulatory T cells in the pathogenesis of acute kidney injury.

The incidence of acute kidney injury (AKI) is on the rise and is associated with high mortality; however, there are currently few effective treatments. Moreover, the relationship between Tregs and other components of the immune microenvironment (IME) in the pathogenesis of AKI remains unclear. We downloaded four publicly accessible AKI datasets, GSE61739, GSE67401, GSE19130, GSE81741, GSE19288 and GSE106993 from the gene expression omnibus (GEO) database. Additionally, we gathered two kidney single-cell sequencing (scRNA-seq) samples from the Department of Organ Transplantation at Zhujiang Hospital of Southern Medical University to investigate chronic kidney transplant rejection (CKTR). Moreover, we also collected three samples of normal kidney tissue from GSE131685. By analysing the differences in immune cells between the AKI and Non-AKI groups, we discovered that the Non-AKI group contained a significantly greater number of Tregs than the AKI group. Additionally, the activation of signalling pathways, such as inflammatory molecules secretion, immune response, glycolytic metabolism, NOTCH, FGF, NF-κB and TLR4, was significantly greater in the AKI group than in the Non-AKI group. Additionally, analysis of single-cell sequencing data revealed that Tregs in patients with chronic kidney rejection and in normal kidney tissue have distinct biology, including immune activation, cytokine production, and activation fractions of signalling pathways such as NOTCH and TLR4. In this study, we found significant differences in the IME between AKI and Non-AKI, including differences in Tregs cells and activation levels of biologically significant signalling pathways. Tregs were associated with lower activity of signalling pathways such as inflammatory response, inflammatory molecule secretion, immune activation, glycolysis.

CARARIME: Interactive web server for comprehensive analysis of renal allograft rejection in immune microenvironment.

Background: Renal transplantation is a very effective treatment for renal failure patients following kidney transplant. However, the clinical benefit is restricted by the high incidence of organ rejection. Therefore, there exists a wealth of literature regarding the mechanism of renal transplant rejection, including a large library of expression data. In recent years, research has shown the immune microenvironment to play an important role in renal transplant rejection. Nephrology web analysis tools currently exist to address chronic nephropathy, renal tumors and children's kidneys, but no such tool exists that analyses the impact of immune microenvironment in renal transplantation rejection. Methods: To fill this gap, we have developed a web page analysis tool called Comprehensive Analysis of Renal Allograft Rerejction in Immune Microenvironment (CARARIME). Results: CARARIME analyzes the gene expression and immune microenvironment of published renal transplant rejection cohorts, including differential analysis (gene expression and immune cells), prognosis analysis (logistics regression, Univariable Cox Regression and Kaplan Meier), correlation analysis, enrichment analysis (GSEA and ssGSEA), and ROC analysis. Conclusions: Using this tool, researchers can easily analyze the immune microenvironment in the context of renal transplant rejection by clicking on the available options, helping to further the development of approaches to renal transplant rejection in the immune microenvironment field. CARARIME can be found in http://www.cararime.com.

Up-regulation of VSIG4 alleviates kidney transplantation-associated acute kidney injury through suppressing inflammation and ROS via regulation of AKT signaling.

Prolonged cold ischemia (CI) is a risk factor for acute kidney injury (AKI) after kidney transplantation (KT). AKI is an abrupt and rapid reduction in renal function due to multi-factors, including inflammation, oxidative stress and apoptosis. V-set immunoglobulin-domain-containing 4 (VSIG4) is a B7 family-related protein and specifically expressed in resting tissue-resident macrophages to mediate various cellular events. In the study, we attempted to explore the effects of VSIG4 on CI/KT-induced AKI in a mouse model. Our results showed that VSIG4 expression was markedly down-regulated in serum of kidney transplant recipients with acute rejection, and in renal tissues of cold ischemia-reperfusion (IR)-operated mice with AKI, which was confirmed in murine macrophages stimulated by oxygen glucose deprivation/reoxygenation (OGD/R). We then found that exogenous VSIG4 markedly ameliorated histological changes in kidney of CI/KT mice by suppressing inflammation and apoptosis through restraining nuclear factor-κB (NF-κB) and Caspase-3 activation, respectively. Oxidative stress and reactive oxygen species (ROS) accumulation in renal tissues were also mitigated by exogenous VSIG4 in CI/KT mice through improving nuclear factor-erythroid 2 related factor 2 (Nrf2) nuclear expression. The inhibitory effects of VSIG4 on inflammation, ROS generation and cell death were confirmed in OGD/R-treated macrophages, which further ameliorated oxidative damage and apoptosis in podocytes. More in vivo and in vitro studies showed that CI/KT- and OGD/R-induced AKI was further accelerated by VSIG4 knockdown. Mechanistically, VSIG4 directly interacted with AKT, and AKT activation was necessary for VSIG4 to govern all these above mentioned cellular processes. Collectively, our findings demonstrated that VSIG4 could mitigate AKI in a CI/KT mouse model, and we identified VSIG4/AKT axis as a promising therapeutic target for the treatment of the disease.

Single-Cell Profiling of Kidney Transplant Recipients With Immunosuppressive Treatment Reveals the Dynamic Immune Characteristics.

Kidney transplantation is currently the first choice of treatment for various types of end-stage renal failure, but there are major limitations in the application of immunosuppressive protocols after kidney transplantation. When the dose of immunosuppressant is too low, graft rejection occurs easily, while a dose that is too high can lead to graft loss. Therefore, it is very important to explore the immune status of patients receiving immunosuppressive agents after kidney transplantation. To compare the immune status of the recipient's whole peripheral blood before and after receipt of immunosuppressive agents, we used single-cell cytometry by time-of-flight (CyTOF) to detect the peripheral blood immune cells in five kidney transplant recipients (KTRs) from the Department of Organ Transplantation of Zhujiang Hospital of Southern Medical University before and after receiving immunosuppressive agents. Based on CyTOF analysis, we detected 363,342 live single immune cells. We found that the immune cell types of the KTRs before and after receipt of immunosuppressive agents were mainly divided into CD4+ T cells, CD8+ T cells, B cells, NK cells/γδ T cells, monocytes/macrophages, granulocytes, and dendritic cells (DCs). After further reclustering of the above cell types, it was found that the immune cell subclusters in the peripheral blood of patients underwent major changes after receipt of immunosuppressants. After receiving immunosuppressive therapy, the peripheral blood of KTRs had significantly increased levels of CD57+NK cells and significantly decreased levels of central memory CD4+ T cells, follicular helper CD4+ T cells, effector CD8+ T cells, effector memory CD8+ T cells and naive CD8+ T cells. This study used CyTOF to classify immune cells in the peripheral blood of KTRs before and after immunosuppressive treatment, further compared differences in the proportions of the main immune cell types and immune cell subgroups before and after receipt of immunosuppressants, and provided relatively accurate information for assessment and treatment strategies for KTRs.

Effects of gallic acid biofabricated rGO nanosheets combined with radiofrequency radiation for the treatment of renal cell carcinoma.

The combination of biologically active compounds and nanomaterials in biomedicine field is growing rapidly and provided excellent forecasts for the progress of facile non-invasive approaches for the diagnosis of cancer therapy. In this present study, we demonstrated that as-prepared gallic acid (GA) coated reduced graphene oxide (rGO) combined with radiofrequency (RF) ablation has facilitated for the treatment of human renal epithelial cancer (A-489) cells without disturbing the renal proximal epithelial (HK-2) cells. The successful biofabrication of GA onto the rGO nanostructure has been elaborated with the support of peak intensities of diffracted X-ray patterns and Raman spectral visualizations. The micrograph imageries are displayed that the warped and ribbed structure containing wrinkled paper-like arrangement with multilayer structure of rGO with assistance of GA molecules. The synthesized GA-rGO nanomaterials exhibited a very good apoptosis and toxic effect on A-489 renal cancer cells, which was found to exhibit enhanced tumor cytotoxicity in RF combination treatment compared to RF treated alone. Moreover, the results are highly cheering to go for functionalized nanomaterial and RF radiation, combined drug delivery system to overcome the limitation to treat kidney cancers.

[Role of miR-663 in acute renal graft rejection: an in vitro study].

OBJECTIVE: To compare the serum miR-663 levels in renal transplant patients with and without acute rejection (AR) and explore the role of miR-663 acute renal graft rejection. METHODS: Real time-PCR was used to determine serum miR-663 levels in renal transplant recipients with and without AR. MTT assay and Annexin V-FITC assay were employed to examine the viability and apoptosis of human renal glomerular endothelial cells (HRGEC) treated with a miR-663 mimic or a miR-663 inhibitor, and ELISA was performed to detect the expression of inflammation-related cytokines including IL-6, IFN-γ, CCL-2 and TNF-α in the cells. Transwell assay was used to examine the effect of miR-663 mimic and miR-663 inhibitor on the chemotactic capability of macrophages. RESULTS: Serum miR-663 level was significantly higher in renal transplant recipients with AR than in those without AR. The miR-663 mimic significantly inhibited the viability of HRGECs and increase the cell apoptosis rate, while miR-663 inhibitor suppressed the cell apoptosis. The miR-663 mimic increased the expression levels of inflammation-related cytokines and enhanced the chemotactic capability of macrophages. CONCLUSION: miR-663 might play important roles in acute renal graft rejection and may become a therapeutic target for treating AR.

MicroRNA-10b downregulation mediates acute rejection of renal allografts by derepressing BCL2L11.

Kidney transplantation is the major therapeutic option for end-stage kidney diseases. However, acute rejection could cause allograft loss in some of these patients. Emerging evidence supports that microRNA (miRNA) dysregulation is implicated in acute allograft rejection. In this study, we used next-generation sequencing to profile miRNA expression in normal and acutely rejected kidney allografts. Among 75 identified dysregulated miRNAs, miR-10b was the most significantly downregulated miRNAs in rejected allografts. Transfecting miR-10b inhibitor into human renal glomerular endothelial cells recapitulated key features of acute allograft rejection, including endothelial cell apoptosis, release of pro-inflammatory cytokines (interleukin-6, tumor necrosis factor α, interferon-γ, and chemokine (C-C motif) ligand 2) and chemotaxis of macrophages whereas transfection of miR-10b mimics had opposite effects. Downregulation of miR-10b directly derepressed the expression of BCL2L11 (an apoptosis inducer) as revealed by luciferase reporter assay. Taken together, miR-10b downregulation mediates many aspects of disease pathogenicity of acute kidney allograft rejection. Restoring miR-10b expression in glomerular endothelial cells could be a novel therapeutic approach to reduce acute renal allograft loss.

[Impact of recipient/donor killer cell immunoglobulin-like receptor gene mismatch on outcomes of renal transplant].

OBJECTIVE: To explore the impact of killer cell immunoglobulin-like receptor (KIR) gene mismatch on the outcomes of renal transplantation. METHODS: We collected the data from 111 donor-recipient pairs of kidney transplant and analyzed the status of KIR gene matching, acute rejection (AR), and 1-year and 3-year survival of the recipients who were followed continuously for over 37 months. RESULTS: Seventeen KIR genes were expressed in both recipient and donor groups, and the frequency of KIR3DS1 was significantly higher in the recipients than in the donors (38.75% vs 24.66%, OR=2.17, χ² = 3.94, P<0.05). The average rate of donor-recipient KIR matching was 82.53%. The donor-recipient KIR2DS1 matching rate was significantly higher in AR group than in no-AR group (85.00% vs 54.95%, χ² = 6.19, P<0.05). The rate of donor-recipient KIR AB-AB genotype was significantly higher in AR group than in no-AR group (33.33% vs 8.00%, P<0.05). The 1- and 3-year survival rates was 94.59% and 82.88% in these recipients, respectively. The frequency of donor KIR-AB genotpye was significantly higher in recipients with poor outcomes (57.89% vs 29.63%, χ² = 8.19, P<0.05); the frequency of both donor and recipient KIR-AB genotype was also significantly higher in recipients with poor prognoses (36.84% vs 9.78%, χ² = 14.87, P<0.05). CONCLUSIONS: KIR3DS1 may be the susceptible gene associated with uremia. A KIR-AB genotype of either the donor or the recipient can increase the risk of AR and reduce the 1- and 3-year survival rate. This finding can be of ethically importance in choosing a living related donor.

Tacrolimus strongly inhibits multiple human UDP-glucuronosyltransferase (UGT) isoforms.

The objective of the present study is to clearly evaluate the inhibitory effects of tacrolimus (tacro) on important UGT isoforms in human liver, including determination of inhibition kinetic type and calculation of inhibition kinetic parameters. An in vitro incubation system was used to investigate the inhibitory effect of tacro on UGT isoforms. The recombinant UGT isoforms were used as enzyme source, and a nonspecific substrate 4-methylumbelliferone (4-MU) was utilized as substrate. Among the tested UGT isoforms, UGT1A1, UGT1A3, UGT2B7 and UGT2B15 were strongly inhibited by tacro in a concentration-dependent manner. Dixon and Lineweaver-Burk plots showed that the inhibition of UGT1A1, UGT1A3, and UGT2B7 was all best fit to competitive inhibition type, and the inhibition of UGT2B15 was best fit to noncompetitive type. The inhibition kinetic parameters (Ki) were determined to be 4.7, 1.3, 1.9, and 4.3 microM for UGT1A1, UGT1A3, UGT2B7, and UGT2B15, respectively. Inhibition of these important UGT isoforms in human liver might be an important reason for clinically frequent drug-drug interaction between tacro and other drugs.

[Effect of CD40 blockade on acute renal graft rejection in rats].

OBJECTIVE: To explore the effect of CD40 blockade in suppressing acute rejection of renal graft in rats. METHODS: With Wistar rats as the donor and male SD rats as the recipients, rat models of acute renal graft rejection was established. The rat models were divided into therapy group and control group, and in the former group, CD40 ligand (CD40L) monoclonal antibody was injected daily for 4 consecutive days starting on the next day following kidney transplantation. On day 5 after the transplantation, the renal graft was harvested for histological examination, and graft rejection was evaluated semiquantitatively. RESULTS: The mean semiquantitative score of the renal graft was 0.63∓0.52 in the therapy group, significantly lower than that of the control group (3.72∓1.48, P<0.05). CONCLUSION: CD40L monoclonal antibody can inhibit acute renal graft in rats.

[The role of miR-223 in the acute rejection after kidney transplantation].

AIM: To explore the role of miR-223 in the acute rejection after kidney transplantation. METHODS: 33 patients who received kidney transplantation in our hospital within a year were collected and 12 of them appeared acute rejection within 1 month after surgery. In all the patients, the peripheral blood miR-223 level was collected and detected by blind arrangements. Furthermore, PBMCs from healthy volunteers were also collected and stimulated by PHA and then miR-223 level was measured. RESULTS: In the peripheral blood cell, the miR-223 was increased 2 times after acute rejection, as well as 3. 76 times after PHA treatment.Furthermore, using miR-223 predicts AR had a specificity of 90% and sensitivity of 92%. CONCLUSION: The miR-223 may have significant role in the acute rejection of kidney transplantation.

[Clinical study of pulmonary infection in kidney transplantation recipients taking new immunosuppressant].

OBJECTIVE: To explore the etiopathogenesis, therapy and incidence of pulmonary infection in kidney transplantation recipients taking new immunosuppressant. METHODS: The clinical data from 752 kidney transplant recipients were retrospectively analyzed, who were divided into 3 groups according to the immunosuppressants administered, namely group A (CsA+MMF+Pred, n=226), group B (FK506+MMF+Pred, n=386) and group C (FK506+Rap+Pred, n=140). The incidence and mortality of pulmonary infection were recorded and the analysis of etiopathogenesis, diagnosis and therapy of pulmonary infection were carried out in the 3 groups. RESULTS: Fifty-three patients acquired post-transplant pulmonary infection. The incidence of pulmonary infection was 7.08% (16/226) in group A, 7.25% (28/386) in group B and 6.43% (9/140) in group C. One patient died in group A and 2 in group B. Among the 53 patients, 24 had simple bacterial infection, 9 had cytomegalovirus infection, 1 had mycotic infection, 17 had combined infection, and 2 had unidentified pathogen infection. Of the pathogenic bacteria detected, 68.35% were Gram-negative. CONCLUSION: Gram-negative bacteria are most likely responsible for pulmonary infection after kidney transplantation, which most possibly occurs within 6 months after kidney transplantation. Early diagnosis and early treatment are critical for decreasing the mortality of severe pneumonia and for improving the survival rate of the patients and grafts.

[Application of tacrolimus and cyclosporine A in HBV-carrying renal transplant recipients].

OBJECTIVE: To compare the long-term effect and safety of tacrolimus (FK506) and cyclosporine (CsA) in kidney transplant (KT) recipients carrying hepatitis B Virus(HBV). METHODS: A total of 109 patients with HBV were randomized into FK506 group (52 cases) and CsA group (57 cases) after KT, and a 2-year-long follow-up of the patients was conducted to record the patient and graft survival, incidence of acute graft rejection and postoperative liver function. RESULTS: The 2-year patient/graft survival was 86.0%/73.7% and 94.2%/90.3% in CsA and FK506 groups, respectively (P<0.05), with incidence of acute rejection of 10.5% and 9.6% (P>0.05), and rate of abnormal liver function of 26.3% and 15.4% (P<0.05), respectively. Eight patients (14.4%) in CsA group required a drug conversion but none in FK506 group. The drug conversion resulted in significant reduction of ALT/AST level from 255.13+/-31.38/201.88+/-21.25 U/L to 31.25+/-11.50/25.13+/-9.68 U/L (P<0.01). CONCLUSION: For HBV-carrying renal transplant recipients, FK506 as the primary choice of immunosuppressant can be more effective and safer than CsA.

[Retrospective study of the risk factors of transplant renal artery stenosis].

OBJECTIVE: To investigate the risk factors of transplant renal artery stenosis (TRAS). METHODS: The clinical records of 26 patients undergoing renal transplantation in our hospital between 2000 and 2005 were retrospectively analyzed, whose final diagnosis of TRAS was established on the basis of arteriographic findings. A case-control group of 52 post-renal transplantation patients were sampled by stratified randomization, whose blood pressure and renal graft function were without complications of avascularity or urinary passage. The two groups were matched for the operation time, gender, age, primary diseases, blood type, PRA and HLA matching and use of immunosuppressants. Possible events related to TRAS such as cold ischemia time, acute rejection, delayed graft function and approaches of arterial anastomosis were compared. RESULTS: Fifteen patients (57.7%) with TRAS had a history of acute rejection episode, 7 (26.9%) had delayed graft function, both rates of which were higher than those in the control group (P<0.05). The cold ischemic time and type of arterial anastomosis showed no significant effect on TRAS occurrence (P>0.05). CONCLUSIONS: Post-transplant renal artery stenosis is closely associated with acute rejection and delayed graft function but not with the cold ischemic time or the type of arterial anastomosis.

[Clinical observation on long-term surviving patients after combined abdominal organ transplantation].

OBJECTIVE: To summarize the treatment experience of long-term surviving patients after combined abdominal organ transplantation. METHODS: From October 2001 to January 2005, 19 patients received combined abdominal organ transplantation in Nanfang Hospital, including 6 with simultaneous kidney-pancreas transplantation (SKPT), 12 with combined liver-kidney transplantation (CLKT), and 1 with simultaneous liver-pancreas transplantation (SLPT). The periods of follow up were from 6 months to 3 years and 8 months. Summarize primary diseases of the patients, factors which impacted on patients long-term survival rate, and immunological characteristics of combined abdominal organ transplantation. RESULTS: All of 19 transplant cases were performed successfully. Among then, 18 were followed up; 16 survived till now; 2 patients undergoing liver-kidney transplantation were dead, one of which died from myocardial infarction in the 18 months after operation, and one died from cytomegalovirus in infection of lung in 13 months; 1 liver-kidney transplantation patient and 2 pancreas-liver transplantation patients experienced acute rejection once; 2 patients were found nephrotoxicity. Among the 18 patients, 4 patients' survival time were over 3 years, 7 over 2 years, 6 over 1 year, 1 over 10 months. CONCLUSIONS: Combined abdominal organ transplantation is effective for treatment of two abdominal organ failure diseases. Factors which impact on patients long-term surviving include choosing suitable recipient, high quality of donated organ, avoidance of surgical complication, the history of myocardial infarction before operation, immunosuppressive regime and virus infection late after transplantation. Combined abdominal organ transplantation has some different immunological characteristics from single organ transplantation.

[Simultaneous liver-pancreas-duodenum transplantation: one case report and review of the literature].

OBJECTIVE: To investigate the effect of treatment on end-stage liver disease and type-I diabetes mellitus with simultaneous liver-pancreas-duodenum transplantation. METHOD: In September 2003, one patient with chronic hepatitis B, liver cirrhosis, hepatic cellular cancer, and insulin-dependent diabetes received simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantation. Liver and pancreas graft function was monitored after transplantation. RESULTS: The function of pancreas allograft was recovered immediately and the patient became insulin-independence postoperatively. The liver allograft was experienced an acute rejection episode and reversed by intravenous bolus methylprednisolone. The recipient was currently liver disease-free and insulin-free more than 21 months. CONCLUSIONS: The simultaneous liver-pancreas-duodenum transplantation is an effective method in the treatment of end-stage liver disease and type-I diabetes mellitus.