Dual-specificity phosphatase 26 protects against kidney injury caused by ischaemia-reperfusion through restraint of TAK1-JNK/p38-mediated apoptosis and inflammation of renal tubular epithelial cells.

Dual-specificity phosphatase 26 (DUSP26) acts as a pivotal player in the transduction of signalling cascades with its dephosphorylating activity. Currently, DUSP26 attracts extensive attention due to its particular function in several pathological conditions. However, whether DUSP26 plays a role in kidney ischaemia-reperfusion (IR) injury is unknown. Aims of the current work were to explore the relevance of DUSP26 in kidney IR damage. DUSP26 levels were found to be decreased in renal tubular epithelial cells following hypoxia-reoxygenation (HR) and kidney samples subjected to IR treatments. DUSP26-overexpressed renal tubular epithelial cells exhibited protection against HR-caused apoptosis and inflammation, while DUSP26-depleted renal tubular epithelial cells were more sensitive to HR damage. Upregulation of DUSP26 in rat kidneys by infecting adenovirus expressing DUSP26 markedly ameliorated kidney injury caused by IR, while also effectively reducing apoptosis and inflammation. The mechanistic studies showed that the activation of transforming growth factor-ß-activated kinase 1 (TAK1)-JNK/p38 MAPK, contributing to kidney injury under HR or IR conditions, was restrained by increasing DUSP26 expression. Pharmacological restraint of TAK1 markedly diminished DUSP26-depletion-exacebated effects on JNK/p38 activation and HR injury of renal tubular cells. The work reported a renal-protective function of DUSP26, which protects against IR-related kidney damage via the intervention effects on the TAK1-JNK/p38 axis. The findings laid a foundation for understanding the molecular pathogenesis of kidney IR injury and provide a prospective target for treating this condition.

Development and validation of a novel nomogram model for predicting delayed graft function in deceased donor kidney transplantation based on pre-transplant biopsies.

BACKGROUND: Delayed graft function (DGF) is an important complication after kidney transplantation surgery. The present study aimed to develop and validate a nomogram for preoperative prediction of DGF on the basis of clinical and histological risk factors. METHODS: The prediction model was constructed in a development cohort comprising 492 kidney transplant recipients from May 2018 to December 2019. Data regarding donor and recipient characteristics, pre-transplantation biopsy results, and machine perfusion parameters were collected, and univariate analysis was performed. The least absolute shrinkage and selection operator regression model was used for variable selection. The prediction model was developed by multivariate logistic regression analysis and presented as a nomogram. An external validation cohort comprising 105 transplantation cases from January 2020 to April 2020 was included in the analysis. RESULTS: 266 donors were included in the development cohort, 458 kidneys (93.1%) were preserved by hypothermic machine perfusion (HMP), 96 (19.51%) of 492 recipients developed DGF. Twenty-eight variables measured before transplantation surgery were included in the LASSO regression model. The nomogram consisted of 12 variables from donor characteristics, pre-transplantation biopsy results and machine perfusion parameters. Internal and external validation showed good discrimination and calibration of the nomogram, with Area Under Curve (AUC) 0.83 (95%CI, 0.78-0.88) and 0.87 (95%CI, 0.80-0.94). Decision curve analysis demonstrated that the nomogram was clinically useful. CONCLUSION: A DGF predicting nomogram was developed that incorporated donor characteristics, pre-transplantation biopsy results, and machine perfusion parameters. This nomogram can be conveniently used for preoperative individualized prediction of DGF in kidney transplant recipients.

USP7 accelerates FMR1-mediated ferroptosis by facilitating TBK1 ubiquitination and DNMT1 deubiquitination after renal ischemia-reperfusion injury.

BACKGROUND: Renal ischemia/reperfusion (I/R) leads to acute kidney injury and is associated with cell ferroptosis, an oxidative programmed cell death. This study aims to explore whether USP7 regulates ferroptosis in rat kidneys suffered I/R and the underlying mechanisms. METHODS: Human renal tubular epithelial cells HK-2 were treated with hypoxia/reoxygenation (H/R) to establish a cell model. The expression of ubiquitin specific peptidase 7 (USP7) in H/R-treated cells was determined. USP7 siRNA was transfected into H/R-treated cells, followed by the detection of cell proliferation, iron ion concentration, oxidative stress levels and glutathione peroxidase 4 (GPX4) and solute carrier family 7-member 11 (SLC7A11) protein levels. Western blotting and immunoprecipitation analyses were performed to detect the effects of USP7 on the ubiquitination of TANK-binding kinase 1 (TBK1) and DNA methyltransferase 1 (DNMT1). Then, H/R-treated cells were transfected with USP7 siRNA alone or together with TBK1 siRNA. Co-immunoprecipitation was used to detect binding relationship between TBK1 and FMRP translational regulator 1 (FMR1). The level of DNMT1 and methylation ratio of the FMR1 promoter region were determined with chromatin immunoprecipitation and methylation specific PCR assays, respectively. Furthermore, USP7 siRNA and FMR1 siRNA were transfected alone or together into H/R-treated cells, followed by the detection of cell functions. An I/R rat model was constructed to analyze the effects of USP7 on renal function in rats. RESULTS: USP7 was significantly upregulated in H/R-treated cells. USP7 interference markedly increased HK-2 cell proliferation and the protein levels of GPX4 and SLC7A11, restrained the iron ion concentration, and ameliorated oxidative stress. USP7 promoted TRIM27-mediated TBK1 ubiquitination and degradation. USP7 inhibition resulted in increased ubiquitination and decreased stability of DNMT1. USP7 was able to recruit DNMT1 to the FMR1 promoter region, which increased promoter methylation rates and suppressed FMR1 expression. TBK1 or FMR1 overexpression could reverse the effects of USP7 on cell functions. Inhibition of USP7 alleviated renal ischemia-reperfusion injury in rats. CONCLUSIONS: USP7 inhibition attenuated I/R-induced renal injury by inhibiting ferroptosis through decreasing ubiquitination of TBK1 and promoting DNMT1-mediated methylation of FMR1.

Predictive value of hypothermic machine perfusion parameters combined perfusate biomarkers in deceased donor kidney transplantation.

BACKGROUND: Delayed graft function (DGF) is the main cause of renal function failure after kidney transplantation. This study aims at investigating the value of hypothermic machine perfusion (HMP) parameters combined with perfusate biomarkers on predicting DGF and the time of renal function recovery after deceased donor (DD) kidney transplantation. METHODS: HMP parameters, perfusate biomarkers and baseline characteristics of 113 DD kidney transplantations from January 1, 2019 to August 31, 2019 in the First Affiliated Hospital of Xi'an Jiaotong University were retrospectively analyzed using univariate and multivariate logistic regression analysis. RESULTS: In this study, the DGF incidence was 17.7% (20/113); The multivariate logistic regression results showed that terminal resistance (OR: 1.879, 95% CI 1.145-3.56) and glutathione S-transferase (GST)(OR = 1.62, 95% CI 1.23-2.46) were risk factors for DGF; The Cox model analysis indicated that terminal resistance was an independent hazard factor for renal function recovery time (HR = 0.823, 95% CI 0.735-0.981). The model combining terminal resistance and GST (AUC = 0.888, 95% CI: 0.842-0.933) significantly improved the DGF predictability compared with the use of terminal resistance (AUC = 0.756, 95% CI 0.693-0.818) or GST alone (AUC = 0.729, 95% CI 0.591-0.806). CONCLUSION: According to the factors analyzed in this study, the combination of HMP parameters and perfusate biomarkers displays a potent DGF predictive value.

Exosomal MicroRNA-374b-5p From Tubular Epithelial Cells Promoted M1 Macrophages Activation and Worsened Renal Ischemia/Reperfusion Injury.

Tubular epithelial cells (TECs) represent the primary site of renal ischemia/reperfusion injury (RIRI). However, whether the damage of TECs could drive the initiation of inflammation was unclear. Here we investigated the role of the TECs and macrophages during RIRI. Increased expression of inflammation response and activated M1 macrophage were determined in the mice model of RIRI. Moreover, we demonstrated global miRNA expression profiling of renal exosomes, and miR-374b-5p was most upregulated in these exosomes in vivo. Inhibition of miR-374b-5p in the mice upon RIR operation would alleviate the kidney injury via decreasing the production of proinflammatory cytokines and suppressing the macrophage activation. Similar results were also identified in the hypoxia-induced cell model where exosomal miR-374b-5p was dramatically upregulated. Uptake of exosomes derived from the hypoxic TECs by macrophages would trigger M1 polarization via transferring miR-374b-5p. Besides, we confirmed that miR-374b-5p could directly bind to Socs1 using a dual-luciferase reporter assay. Notably, when we injected the miR-374b-5p-enriched exosomes into mice, a high-level inflammatory response and M1 macrophage activation were performed. Our studies demonstrated that exosomal miR-374b-5p played an essential role in the communication between injured TECs and macrophages, resulting in the M1 macrophage activation during RIRI. The blockage of the release of such exosomes may serve as a new therapeutic strategy for RIRI.

miR-182-5p and miR-378a-3p regulate ferroptosis in I/R-induced renal injury.

Renal tubular cell death is the key factor of the pathogenesis of ischemia/reperfusion (I/R) kidney injury. Ferroptosis is a type of regulated cell death (RCD) found in various diseases. However, the underlying molecular mechanisms related to ferroptosis in renal I/R injury remain unclear. In the present study, we investigated the regulatory role of microRNAs on ferroptosis in I/R-induced renal injury. We established the I/R-induced renal injury model in rats, and H/R induced HK-2 cells injury in vitro. CCK-8 was used to measure cell viability. Fe2+ and ROS levels were assayed to evaluate the activation of ferroptosis. We performed RNA sequencing to profile the miRNAs expression in H/R-induced injury and ferroptosis. Western blot analysis was used to detect the protein expression. qRT-PCR was used to detect the mRNA and miRNA levels in cells and tissues. We further used luciferase reporter assay to verify the direct targeting effect of miRNA. We found that ischemia/reperfusion-induced ferroptosis in rat's kidney. We identified that miR-182-5p and miR-378a-3p were upregulated in the ferroptosis and H/R-induced injury, and correlates reversely with glutathione peroxidases 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression in renal I/R injury tissues, respectively. In vitro studies showed that miR-182-5p and miR-378a-3p induced ferroptosis in cells. We further found that miR-182-5p and miR-378a-3p regulated the expression of GPX4 and SLC7A11 negatively by directly binding to the 3'UTR of GPX4 and SLC7A11 mRNA. In vivo study showed that silencing miR-182-5p and miR-378a-3p alleviated the I/R-induced renal injury in rats. In conclusion, we demonstrated that I/R induced upregulation of miR-182-5p and miR-378a-3p, leading to activation of ferroptosis in renal injury through downregulation of GPX4 and SLC7A11.

Knockdown of ANGPTL2 Protects Renal Tubular Epithelial Cells Against Hypoxia/Reoxygenation-Induced Injury via Suppressing TLR4/NF-κB Signaling Pathway and Activating Nrf2/HO-1 Signaling Pathway.

Renal ischemia/reperfusion (I/R) injury is a particular threat faced by clinicians in kidney transplantation. Previous studies have confirmed the importance of oxidative stress and inflammation in the pathogenesis of I/R injury. Angiopoietin-like protein 2 (ANGPTL2) belongs to the angiopoietin-like family and has been found to be involved in the regulation of kidney function as well as oxidative and inflammatory response. In the present study, we aimed to evaluate the role of ANGPTL2 in renal I/R injury in vitro. The human proximal tubular epithelial cell line (HK-2 cells) was subjected to hypoxia/ reoxygenation (H/R) to mimic I/R injury in vitro. We found that the expression level of ANGPTL2 was markedly increased in H/R-induced HK-2 cells. Knockdown of ANGPTL2 improved the decreased cell viability of HK-2 cells in response to H/R stimulation. Knockdown of ANGPTL2 significantly inhibited the H/R-caused increase in levels of reactive oxygen species, malondialdehyde, and proinflammatory cytokines, including interleukin (IL)-6, IL-1ß, and tumor necrosis factor-alpha, as well as a decrease in superoxide dismutase activity in the HK-2 cells. Besides, the increased bax expression and caspase-3 activity and decreased bcl-2 expression in H/R-induced HK-2 cells were also attenuated by knockdown of ANGPTL2. Moreover, ANGPTL2 overexpression showed the opposite effects. Further mechanism investigations proved that the activation of Nrf2/HO-1 signaling pathway and the inhibition of toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway were both implicated in the renal-protective effects of ANGPTL2 knockdown on H/R-induced HK-2 cells. Collectively, these findings suggested that ANGPTL2 might be a new possible target for the treatment and prevention of renal I/R injury.

Inhibition of myeloid differentiation protein 2 attenuates renal ischemia/reperfusion-induced oxidative stress and inflammation via suppressing TLR4/TRAF6/NF-kB pathway.

As a major risk factor of acute kidney injury, renal ischemia/reperfusion (I/R) has a high mortality rate. Myeloid differentiation protein 2 (MD-2) is a secretory glycoprotein that plays an important role in inflammation. Our study aimed to explore the roles of MD-2 in I/R-induced inflammation and oxidative stress in vivo and in vitro. For the in vivo studies, male C57BL/6 mice were randomly divided into four groups: 1) sham, 2) I/R, 3) negative control for siRNA (siNC) and I/R treatment, or 4) MD-2 siRNA (siMD-2) and I/R. Levels of blood urea nitrogen and creatinine in the plasma were tested, and hematoxylin and eosin staining was performed at 24 h after I/R injury. The inflammatory cytokines TNF-α, IL-6, and MCP-1 were measured using ELISA and Real-time qPCR (RT-qPCR). Malondialdehyde (MDA) content and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity were estimated. For the in vitro studies, HK-2 cells were transfected with siMD-2 and then exposed to hypoxia/reoxygenation (H/R). Inflammatory cytokine expression and oxidative stress then were evaluated. We found decreased levels of blood urea nitrogen and creatinine levels after MD-2 silencing. MD-2 deficiency improved histological damage. MD-2 downregulation attenuated levels of inflammatory cytokines. Inhibition of MD-2 resulted in reduced MDA content and increased SOD, CAT, and GPx activity. Loss of function of MD-2 inhibited the H/R-induced production and expression of inflammatory cytokines. MD-2 silencing reduced MDA content after H/R, and MD-2 suppression enhanced SOD, CAT, and GPx activity. MD-2 deficiency also blocked H/R-mediated activation of the TLR4/TRAF6/NF-κB pathway, and pyrrolidinedithiocarbamate (PDTC) pretreatment strengthened the anti-inflammatory and antioxidant damage effects of MD-2 silencing. Taken together, our study revealed that MD-2 deficiency ameliorated renal I/R-induced inflammation and oxidative stress via inhibition of TLR4/TRAF6/NF-κB pathway.

Comprehensive assessment of deceased donor kidneys with clinical characteristics, pre-implant biopsy histopathology and hypothermic mechanical perfusion parameters is highly predictive of delayed graft function.

Background: Due to the current high demand for transplant tissue, an increasing proportion of kidney donors are considered extended criteria donors, which results in a higher incidence of delayed graft function (DGF) in organ recipients. Therefore, it is important to fully investigate the risk factors of DGF, and establish a prediction system to assess donor kidney quality before transplantation.Methods: A total of 333 donation after cardiac death kidney transplant recipients were included in this retrospective study. Both univariate and multivariate analyses were used to analyze the risk factors of DGF occurrence. Receiver operating characteristic (ROC) curves were used to analyze the predictive value of variables on DGF posttransplant.Results: The donor clinical scores, kidney histopathologic Remuzzi scores and hypothermic mechanical perfusion (HMP) parameters (flow and resistance index) were all correlated. 46 recipients developed DGF postoperatively, with an incidence of 13.8% (46/333). Multivariate logistic regression analysis of the kidney transplants revealed that the independent risk factors of DGF occurrence post-transplantation included donor score (OR = 1.12, 95% CI 1.06-1.19, p < 0.001), Remuzzi score (OR = 1.21, 95% CI 1.02-1.43, p = 0.029) and acute tubular injury (ATI) score (OR = 4.72, 95% CI 2.32-9.60, p < 0.001). Prediction of DGF with ROC curve showed that the area under the curve was increased to 0.89 when all variables (donor score, Remuzzi score, ATI score and HMP resistance index) were considered together.Conclusions: Combination of donor clinical information, kidney pre-implant histopathology and HMP parameters provide a more accurate prediction of DGF occurrence post-transplantation than any of the measures alone.

C1q/TNF-related protein 6 (CTRP6) attenuates renal ischaemia-reperfusion injury through the activation of PI3K/Akt signalling pathway.

C1q/TNF-related protein 6 (CTRP6) is a member of the CTRP family that has been reported to exhibit a nephroprotective effect. However, the role of CTRP6 in renal ischaemia/reperfusion (I/R) injury (IRI) remains unclear. In the present study, we aimed to explore the protective effect of CTRP6 in renal IRI and the potential mechanism. We found that CTRP6 expression was markedly decreased in the kidneys of mice subjected to I/R and HK-2 cells in response to hypoxia/reoxygenation (H/R) stimulation. Recombinant CTRP6 protein protected against renal I/R injury by the reduction of blood urea nitrogen (BUN) and creatinine levels. The increased production of ROS and malondialdehyde (MDA), as well the decreased activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) caused by H/R induction were mitigated by CTRP6 in HK-2 cells. The caspase-3 activity and apoptotic rate were both decreased in CTRP6-overexpressing HK-2 cells. In addition, we also found that knockdown of CTRP6 aggravated H/R-caused oxidative stress and cell apoptosis in HK-2 cells. Moreover, CTRP6 overexpression enhanced the H/R-stimulated activation of PI3K/Akt pathway in HK-2 cells. Inhibition of PI3K reversed the nephroprotective effects of CTRP6 in HK-2 cells. Taken together, CTRP6 exerted protective effects against H/R-caused oxidative injury in HK-2 cells via activating the PI3K/Akt pathway.

Prediction of kidney transplant outcome based on different DGF definitions in Chinese deceased donation.

BACKGROUND: Delayed graft function (DGF) is an important complication of kidney transplantation and can be diagnosed according to different definitions. DGF has been suggested to be associated with the long-term outcome of kidney transplantation surgery. However, the best DGF definition for predicting renal transplant outcomes in Chinese donations after cardiac death (DCDs) remains to be determined. METHOD: A total of 372 DCD kidney transplant recipients from June 2013 to July 2017 in the First Affiliated Hospital of Xi'an Jiaotong University were included in this retrospective study to compare 6 different DGF definitions. The relationships of the DGF definitions with transplant outcome were analyzed, including graft loss (GL) and death-censored graft loss (death-censored GL). Renal function indicators, including one-year estimated glomerular filtration rate (eGFR) and three-year eGFR, and were compared between different DGF groups. RESULTS: The incidence of DGF varied from 4.19 to 35.22% according to the different DGF diagnoses. All DGF definitions were significantly associated with three-year GL as well as death-censored GL. DGF based on requirement of hemodialysis within the first week had the best predictive value for GL (AUC 0.77), and DGF based on sCr variation during the first 3 days post-transplant had the best predictive value for three-year death-censored GL (AUC 0.79). Combination of the 48-h sCr reduction ratio and classical DGF can improve the AUC for GL (AUC 0.85) as well as the predictive accuracy for death-censored GL (83.3%). CONCLUSION: DGF was an independent risk factor for poor transplant outcome. The combination of need for hemodialysis within the first week and the 48-h serum creatinine reduction rate has a better predictive value for patient and poor graft outcome.

FOXP1 inhibits high glucose-induced ECM accumulation and oxidative stress in mesangial cells.

Diabetic nephropathy (DN) is a common complication of diabetes that remains the major cause of end-stage renal disease (ESRD). Forkhead box P1 (FOXP1) is a member of FOX family involved in the progression of diabetes. However, the pathogenic role of FOXP1 in DN remains unclear. This study was aimed to explore the effects of FOXP1 on glomerular mesangial cells (MCs) in response to high glucose (HG) stimulation. We found that HG stimulation markedly inhibited the FOXP1 expression in MCs in dose-and time-dependent manner. CCK-8 assay proved that FOXP1 overexpression attenuated HG-induced cell proliferation in MCs. FOXP1 exhibited anti-oxidative activity in HG-induced MCs, as proved by the decreased production of ROS and expressions of ROS producing enzymes, NADPH oxidase (NOX) 2 and NOX4. Besides, FOXP1 suppressed the expression and secretion of extracellular matrix (ECM) proteins including collagen IV (Col IV) and fibronectin (FN). Furthermore, FOXP1 overexpression significantly prevented HG-induced activation of Akt/mTOR signaling in MCs, and Akt activator blocked FOXP1-mediated cell proliferation, ROS production and ECM accumulation in MCs. Collectively, FOXP1 prevented HG-induced proliferation, oxidative stress, and ECM accumulation in MCs via inhibiting the activation of Akt/mTOR signaling pathway. The findings suggested that FOXP1 might be a therapeutic target for the treatment of DN.

Role of prostaglandin E2 receptor 4 in the modulation of apoptosis and mitophagy during ischemia/reperfusion injury in the kidney.

The mechanisms by which prostaglandin E2 receptor 4 (EP4) protects against renal ischemia­reperfusion (I/R) injury (IRI) remain to be fully elucidated. In the present study, the protective effects of EP4 signaling on renal mitochondria and against renal IRI, as well as the underlying mechanisms, were investigated. A rat model of renal IRI was established. The right kidney was separated without damaging the artery clip, and the renal blood perfusion was then restored after 60 min. One group of animals was treated with EP4 agonists prior to I/R. The mitochondrial mass, the copy number of mitochondrial (mt)DNA, adenosine triphosphate (ATP) production and mitochondrial autophagy were analyzed. It was identified that renal IRI reduced the mitochondrial mass, decreased the mtDNA copy number and inhibited ATP production. The loss of renal mitochondria was attributed to the excessive mitochondrial autophagy induced by renal IRI. Pre­treatment with EP4 agonist inhibited excessive mitochondrial autophagy, the loss of mitochondria and maintained and the energy imbalance within the cells. It was indicated that renal IRI causes excessive mitochondrial autophagy, which is one of the important causes of renal dysfunction.

Probiotics ameliorate renal ischemia-reperfusion injury by modulating the phenotype of macrophages through the IL-10/GSK-3ß/PTEN signaling pathway.

After renal ischemic reperfusion injury, a series of pathological changes, such as impaired intestinal barrier function, intestinal flora, and endotoxin translocation, are caused by intestinal ischemia and hypoxia, which then trigger systemic inflammatory responses and affect the condition and prognosis of the patients. In this study, a rat model of ischemia-reperfusion injury was established by examining changes in renal function, intestinal barrier function, inflammatory index, oxidative stress, and macrophage phenotypes to evaluate the effect of probiotic VSL#3 on renal ischemia-reperfusion injury. The results showed that, after VSL#3 intervention, the levels of BUN, Scr, Cys C, PRO, and NGAL were all significantly decreased compared with the I/R group, while the value of Ccr showed a significant increase. In addition, the concentrations of MPO, IL-1ß, TNF-α, IL-6, ED-1, and PCNA were all significantly lower than those in the I/R group, while the levels of endotoxin, DOA, and D-lactic acid were significantly decreased. Furthermore, the proteins associated with intestinal barrier functions, such as ZO-1, Occludin, and Claudin-1, were significantly upregulated compared with the I/R group. Overall, the VSL#3 intervention group was able to maintain the required number of beneficial intestinal flora and to inhibit the proliferation of harmful bacteria. At the same time, the VSL#3 intervention could also prevent the decrease in the levels of CAT, GSH-PX, H2O2, and T-SOD, while downregulating the expression of Keap1 and Nrf2. After the intervention with the VSL#3, the expression levels of CD68 and CD86 proteins were significantly decreased, while the expression levels of CD163 and CD206 proteins were significantly higher. Further experiments confirmed that the expression of iNOS protein was significantly decreased after the VSL#3 intervention, and the expression of Arg-1 and Ym1 proteins was significantly increased. The VSL#3 was able to induce high expressions of p-GSK-3ß and p-PTEN proteins, while the use of IL-10 antibody impaired the effect of the VSL#3. In summary, this research confirms that probiotics can alleviate renal dysfunction caused by ischemia and reperfusion by protecting the intestinal barrier function and maintaining the functions of intestinal flora. The pathway screening test of this study suggests that IL-10/GSK3ß/PTEN may play an important role in the process of the prototypic VSL#3 inducing M2 transformation of macrophages.

Predictive Score Model for Delayed Graft Function Based on Hypothermic Machine Perfusion Variables in Kidney Transplantation.

BACKGROUND: Hypothermic machine perfusion (HMP) is being used more often in cardiac death kidney transplantation; however, the significance of assessing organ quality and predicting delayed graft function (DGF) by HMP parameters is still controversial. Therefore, we used a readily available HMP variable to design a scoring model that can identify the highest risk of DGF and provide the guidance and advice for organ allocation and DCD kidney assessment. METHODS: From September 1, 2012 to August 31, 2016, 366 qualified kidneys were randomly assigned to the development and validation cohorts in a 2:1 distribution. The HMP variables of the development cohort served as candidate univariate predictors for DGF. The independent predictors of DGF were identified by multivariate logistic regression analysis with a P < 0.05. According to the odds ratios (ORs) value, each HMP variable was assigned a weighted integer, and the sum of the integers indicated the total risk score for each kidney. The validation cohort was used to verify the accuracy and reliability of the scoring model. RESULTS: HMP duration (OR = 1.165, 95% confidence interval [CI]: 1.008-1.360, P = 0.043), resistance (OR = 2.190, 95% CI: 1.032-10.20, P < 0.001), and flow rate (OR = 0.931, 95% CI: 0.894-0.967, P = 0.011) were the independent predictors of identified DGF. The HMP predictive score ranged from 0 to 14, and there was a clear increase in the incidence of DGF, from the low predictive score group to the very high predictive score group. We formed four increasingly serious risk categories (scores 0-3, 4-7, 8-11, and 12-14) according to the frequency associated with the different risk scores of DGF. The HMP predictive score indicates good discriminative power with a c-statistic of 0.706 in the validation cohort, and it had significantly better prediction value for DGF compared to both terminal flow (P = 0.012) and resistance (P = 0.006). CONCLUSION: The HMP predictive score is a good noninvasive tool for assessing the quality of DCD kidneys, and it is potentially useful for physicians in making optimal decisions about the organs donated.

Beneficial Effect of Moderately Increasing Hypothermic Machine Perfusion Pressure on Donor after Cardiac Death Renal Transplantation.

BACKGROUND: Vascular resistance and flow rate during hypothermic machine perfusion (HMP) of kidneys is correlated with graft function. We aimed to determine the effects of increasing HMP pressure versus maintaining the initial pressure on kidney transplantation outcomes. METHODS: We retrospectively reviewed the data of 76 primary transplantation patients who received HMP-preserved kidneys from 48 donors after cardiac death between September 1, 2013, and August 31, 2015. HMP pressure was increased from 30 to 40 mmHg (1 mmHg = 0.133 kPa) in kidneys with poor flow and/or vascular resistance (increased pressure [IP] group; 36 patients); otherwise, the initial pressure was maintained (constant pressure group; 40 patients). Finally, the clinical characteristics and transplantation outcomes in both groups were assessed. RESULTS: Delayed graft function (DGF) incidence, 1-year allograft, patient survival, kidney function recovery time, and serum creatinine level on day 30 were similar in both groups, with improved flow and resistance in the IP group. Among patients with DGF, kidney function recovery time and DGF duration were ameliorated in the IP group. Multivariate logistic regression analysis revealed that donor hypertension (odds ratio [OR]: 1.43, 95% confidence interval [CI]: 1.02-2.06, P = 0.035), donor terminal serum creatinine (OR: 1.27, 95% CI: 1.06-1.62, P = 0.023), warm ischemic time (OR: 3.45, 95% CI: 1.97-6.37, P = 0.002), and terminal resistance (OR: 3.12, 95% CI: 1.76-6.09, P = 0.012) were independent predictors of DGF. Cox proportional hazards analysis showed that terminal resistance (hazard ratio: 2.06, 95% CI: 1.32-5.16, P = 0.032) significantly affected graft survival. CONCLUSION: Increased HMP pressure improves graft perfusion but does not affect DGF incidence or 1-year graft survival.

LncRNA CRNDE is a biomarker for clinical progression and poor prognosis in clear cell renal cell carcinoma.

Colorectal neoplasia differentially expressed (CRNDE) served as an oncogenic long noncoding RNA (lncRNA) to be involved in the initialization and development of human cancers. However, the clinical significance and biological function of CRNDE in clear cell renal cell carcinoma (ccRCC) was not fully understood. In our study, we found CRNDE levels were increased in ccRCC tissue specimens and cell lines, and corrected with advanced clinical stage, large tumor size, lymph node metastasis, distant metastasis, and poor pathological grade in patients with ccRCC. Furthermore, levels of CRNDE were negatively correlated with overall survival of patients with ccRCC, and high-expression of CRNDE was an independent poor prognostic factor for patients with ccRCC. Moreover, loss-of-function and gain-of-function approaches showed CRNDE-enhanced ccRCC cell migration and invasion through modulating EMT-associated genes. In conclusion, CRNDE acts as an oncogenic lncRNA in ccRCC.

Early Immunosuppressive Exposure of Enteric-Coated-Mycophenolate Sodium Plus Tacrolimus Associated with Acute Rejection in Expanded Criteria Donor Kidney Transplantation.

BACKGROUND: Immunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection (BPAR) after expanded criteria donor (ECD) kidney transplantation. The aim of this study was to investigate the relationships between early immunosuppressive exposure and the development of BPAR. METHODS: We performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolimus (Tac), and prednisone. The levels of mycophenolic acid-area under the curve (MPA-AUC)0-12h and Tac C0were measured at the 1st week and the 1st month posttransplant, respectively. The correlation was assessed by multivariate logistic regression. RESULTS: The occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC0-12h at the 1st week posttransplant was found in BPAR recipients (38.42 ± 8.37 vs. 50.64 ± 13.22, P < 0.01). In addition, the incidence of BPAR was significantly high (P < 0.05) when the MPA-AUC0-12hlevel was <30 mg·h-1·L-1 at the 1st week (15.0% vs. 44.4%) or the Tac C0was <4 ng/ml at the 1st month posttransplant (33.3% vs. 21.6%). Multivariable logistic regression analysis showed that the MPA-AUC0-12h at the 1st week (OR: 0.842, 95% CI: 0.784-0.903) and the Tac C0at the 1st month (OR: 0.904, 95% CI: 0.822-0.986) had significant inverse correlation with BPAR (P < 0.05). CONCLUSIONS: Low-level exposure of MPA and Tac C0in the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC0-12h <30 mg·h-1·L-1 and Tac C0 <4 ng/ml should be avoided in the first few weeks after transplantation.

Predictive Score Model for Delayed Graft Function Based on Easily Available Variables before Kidney Donation after Cardiac Death.

BACKGROUND: How to evaluate the quality of donation after cardiac death (DCD) kidneys has become a critical problem in kidney transplantation in China. Hence, the aim of this study was to develop a simple donor risk score model to evaluate the quality of DCD kidneys before DCD. METHODS: A total of 543 qualified kidneys were randomized in a 2:1 manner to create the development and validation cohorts. The donor variables in the development cohort were considered as candidate univariate predictors of delayed graft function (DGF). Multivariate logistic regression was then used to identify independent predictors of DGF with P < 0.05. Date from validation cohort were used to validate the donor scoring model. RESULTS: Based on the odds ratios, eight identified variables were assigned a weighted integer; the sum of the integer was the total risk score for each kidney. The donor risk score, ranging from 0 to 28, demonstrated good discriminative power with a C-statistic of 0.790. Similar results were obtained from validation cohort with C-statistic of 0.783. Based on the obtained frequencies of DGF in relation to different risk scores, we formed four risk categories of increasing severity (scores 0-4, 5-9, 10-14, and 15-28). CONCLUSIONS: The scoring model might be a good noninvasive tool for assessing the quality of DCD kidneys before donation and potentially useful for physicians to make optimal decisions about donor organ offers.

Outcomes for primary kidney transplantation from donation after Citizens' death in China: a single center experience of 367 cases.

BACKGROUND: The cases of donation after brain death followed by circulatory death (DBCD) and donation after cardiac death (DCD) have been increased year by year in China. Further research is needed to understand in the outcomes and risk factors of delayed graft function (DGF) in order to minimize the risk of DGF and ameliorate its potential impact on long-term outcomes. This study was to explore the differences in outcomes between DBCD and DCD transplant and the main risk factors for DGF in DBCD. METHODS: Retrospective analysis of the clinical data of 367donations after citizens' death kidney transplant procedures (donors and recipients) between July 2012 and August 2015 at our center. RESULTS: During the study period, the donation success rate was 25.3%. 164 cases of DBCD and 35 cases of DCD had been implemented and 367 kidneys were transplanted. The incidence of DGF in DBCD group were significantly lower than that of DCD group (12.0% vs. 27.0%, p = 0.002). The 1-year percent freedom from acute rejection (AR) was significantly higher in DBCD group compared with it of DCD group (94% vs. 82%, p = 0.036). Multivariate logistic regression analysis of the kidney transplants revealed that the high risk factors for DGF after renal transplantation in DBCD were history of hypertension (Odds Ratio [OR] = 5.88, 95% CI: 1.90 to 18.2, p = 0.002), low blood pressure (BP < 80 mmHg) (OR = 4.86, 95% CI: 1.58 to 14.9, p = 0.006) and serum creatinine of donor (OR = 1.09, 95% CI: 1.03 to 1.16, p = 0.003) before donation. CONCLUSIONS: The outcomes of DBCD could be better than DCD in DGF and AR. The main risk factors for DGF in DBCD kidney transplants are donors with a history of hypertension, low blood pressure, and serum creatinine of donor before donation.