Association of time-averaged serum uric acid level with clinicopathological information and long-term outcomes in patients with IgA nephropathy.

Objective: Whether serum uric acid (SUA) at baseline could been identiûed as a risk factor for progression in IgA nephropathy (IgAN) patients remains unclear, therefore, long- term SUA control levels must be monitored. We aimed to investigate the relevant factors affecting time-averaged SUA (TA-SUA) and to assess the prognostic value of TA-SUA in IgAN. Methods: This retrospective study included 152 patients with IgAN. The relationships between TA-SUA and clinicopathological features and renal outcomes (defined as the doubling of the baseline serum creatinine level or end-stage renal disease) were analyzed in groups divided by quartiles of TA-SUA levels, the presence of hyperuricemia, and sex. Results: Patients with high TA-SUA levels had higher levels of baseline SUA, blood urea nitrogen (BUN), triglycerides, serum C3 and serum C4 and were more likely to be male and have hypertension, proteinuria, poor renal function, and pathological injuries including high grades of tubular atrophy/interstitial fibrosis (T1-T2). These patients had a poorer prognosis compared with patients with low TA-SUA levels. The TA-SUA level was positively correlated with baseline age and BUN, triglycerides, serum C3, and serum C4 levels, and negatively correlated with baseline eGFR. Survival curve analysis indicated that persistent hyperuricemia was associated with significantly poorer renal outcomes than normo-uricemia in both men and women. The TA-SUA level also was an independent predictor of renal outcome in patients with IgAN, with optimal cutoû values of 451.38 µmol/L (area under the curve (AUC) = 0.934) for men and 492.83 µmol/L (AUC = 0.768) for women. Conclusions: The TA-SUA level is associated with triglyceride level, complement component levels, renal function, and pathological severity of IgAN, and it may be a prognostic indicator in male and female patients with IgAN.

Gasdermin D-Mediated Pyroptosis Promotes the Development of Atherosclerosis.

Atherosclerosis is a chronic inflammatory cardiovascular disease with a high-morbidity and mortality rate. An increasing number of studies have addressed the crucial contribution of gasdermin D (GSDMD)-mediated pyroptosis, which is triggered by the inflammasomes to the development of atherosclerosis. However, the underlying mechanism is still unclear. This study aimed to uncover the detailed role of GSDMD in the development of atherosclerosis. An atherosclerotic model was established in Gsdmd-/-/Ldlr-/- mice and Gsdmd+/+/Ldlr-/- mice fed with a high-fat diet. The atherosclerotic lesions, the activation of GSDMD, and the expression level of inflammatory cytokines and chemokines were evaluated. Gsdmd deletion ameliorated the atherosclerotic lesion sizes and the infiltration of immune cells and inflammatory cells in the aortas of mice. Additionally, Gsdmd deletion suppressed the pyroptosis of macrophages and endothelial cells induced by the serum of Ldlr-/- mice fed with a high-fat diet. Furthermore, the formation of neutrophil extracellular traps was also attenuated by knockout of Gsdmd. Bone marrow chimeras confirmed that the genetic deficiency of Gsdmd in both immune cells and intrinsic cells played a role in the promotion of arteriosclerosis. Collectively, our study demonstrated that Gsdmd deletion hindered the pathogenesis of atherosclerosis by inhibiting endothelial cell and macrophage cell death, and the formation of neutrophil extracellular traps.

Time-Averaged Hematuria as a Prognostic Indicator of Renal Outcome in Patients with IgA Nephropathy.

We aim to investigate the association of time-averaged hematuria (TA-hematuria) with the progression of IgA nephropathy (IgAN). Based on TA-hematuria during follow-up, 152 patients with IgAN were divided into a hematuria remission group (≤28 red blood cells [RBCs]/µL) and a persistent hematuria group (>28 RBCs/µL). The persistent hematuria group had a higher percentage of patients with macroscopic hematuria, lower levels of hemoglobin and TA-serum albumin, and more severe renal pathologic lesions. The composite endpoint is defined as a doubling of the baseline SCr level (D-SCr), or the presence of ESRD. During the mean follow-up of 58.08 ± 23.51 months, 15 patients (9.9%) reached the primary outcome of ESRD and 19 patients (12.5%) reached the combined renal endpoint. Kaplan-Meier analysis showed that the persistent hematuria group had a lower renal survival rate. The persistent hematuria patients who were incorporated with proteinuria (≥1.0 g/day) and low TA-serum albumin (<40 g/L) had the worst renal outcomes. Multivariate Cox regression indicated that TA-hematuria (hazard ratio [HR] = 0.004, 95% CI: 0.001, 0.008; p = 0.010) was independently associated with the progression of IgAN. Receiver operating characteristic analysis indicated the optimal TA-hematuria cutoff value for predicting the progression of IgAN was 201.21 RBCs/µL in females and 37.25 RBCs/µL in males.

Risk Factors for Progression of CKD with and without Diabetes.

Objective: We aim to identify independent risk factors to predict CKD progression to end stage renal disease (ESRD) in patients with or without diabetes. Methods: In this retrospective study, we enrolled CKD stage 3-4 patients between January 2013 and December 2018 and followed them until December 2020 or the initiation of dialysis. We used Kaplan-Meier to plot the survival curve. Univariate and multivariable Cox proportional hazards model was used to explore risk factors affecting the progression of CKD. The final model was used to construct nomogram for predicting CKD progression. Calibration plots and concordance index (C-index) were used to evaluate the accuracy and discrimination of the risk model. Results: We enrolled 309 CKD patients, including 80 cases in G3a, 98 cases in G3b, and 131 cases in G4. Among them, 141 patients had diabetes and 168 did not. The mean age of patients at enrolled was 57.86 ± 15.10 years, and 67% were male. The median follow-up time was 25.6 months. There were 81 patients (26.2%) that started dialysis in the total CKD cohort, 52 cases (36.9%) in the CKD with diabetes group, and 29 cases (17.3%) in the CKD without diabetes group. Hypoalbuminemia (HR =2.655, P < 0.001), proteinuria (HR =2.592, P = 0.042), increased LDL (HR =2.494, P < 0.001), diabetes (HR =2.759, P < 0.001), hypertension (HR =3.471, P = 0.037), and CKD stage (HR =2.001, P = 0.046) were risk factors for CKD progression to ESRD in the overall population. For those without diabetes, only hypoalbuminemia (HR =2.938, P = 0.030) was a risk factor for CKD progression to ESRD. For those with diabetes, both hypoalbuminemia (HR =2.758, P = 0.002), the increased level of LDL (HR =3.982, P < 0.001), and CKD stage (HR =3.781, P = 0.001) were risk factors for CKD progression to ESRD. The C-index of the final nomograms was 0.760 (P < 0.001). Conclusions: The results from our risk factor model suggest that CKD disease progression can be predicted and early strategic intervention is necessary for CKD patients to avoid renal function deterioration.

Value of a quantitative model of axillary venous blood flow spectrum for the detection of central venous stenosis in patients undergoing hemodialysis via radiocephalic arteriovenous fistula.

Background: Central venous stenosis (CVS) of radiocephalic arteriovenous fistula (RCAVF) affects RCAVF function and longevity. Ultrasound screening for CVS is limited by acoustic window. Herein, we analyzed the quantitative axillary venous (AxV) spectrum in hemodialysis patients via RCAVF, and constructed central venous stenosis index (CVSI) model based on the spectrum parameters to early detect resting asymptomatic CVS. Methods: From August 2017 to May 2021, stage 5 chronic kidney disease (CKD) patients dialysed via RCAVF at the First Affiliated Hospital of Fujian Medical University were included in this study. No CVS-related symptoms were found and the pulsation at the arteriovenous anastomosis was normal. However, the patients had the sensation of swelling in the ipsilateral upper limb during dialysis; the venous pressure advanced upon the completion of dialysis; or both (n=52). The inclusion criteria were as follows: (I) Ultrasound (US) showed that the temporal phases of the AxV spectrum were "normal"; and (II) CVS was confirmed by digital subtraction angiography (DSA). The exclusion criteria were as follows: (I) stent placement; (II) multiple stenosis; and (III) placement of central venous catheter. A total of 37 patients participated in the analysis. Eighteen patients were included in the CVS group, and 19 cases without CVS were included in the control group. Independent sample t-test was used to screen each parameter of the AxV spectrum, and a CVSI model was constructed by principal component analysis (PCA). The receiver operating characteristic curve (ROC) was applied to analyze the diagnostic value of CVSI. Results: According to the independent sample t-test, 9 parameters were found to have statistical significance (all P<0.05); they were analyzed by PCA, and the CVSI model was constructed. The ROC showed that CVSI had diagnostic value for CVS. When the cut-off value of CVSI was 7.13, the maximum value of the Youden index was 0.842, with a sensitivity of 100% and a specificity of 84.2%. Conclusions: The CVSI helps to early detect resting asymptomatic CVS and dramatically increases the detection rate of CVS.

GSDME-mediated pyroptosis promotes inflammation and fibrosis in obstructive nephropathy.

Renal tubular cell (RTC) death and inflammation contribute to the progression of obstructive nephropathy, but its underlying mechanisms have not been fully elucidated. Here, we showed that Gasdermin E (GSDME) expression level and GSDME-N domain generation determined the RTC fate response to TNFα under the condition of oxygen-glucose-serum deprivation. Deletion of Caspase-3 (Casp3) or Gsdme alleviated renal tubule damage and inflammation and finally prevented the development of hydronephrosis and kidney fibrosis after ureteral obstruction. Using bone marrow transplantation and cell type-specific Casp3 knockout mice, we demonstrated that Casp3/GSDME-mediated pyroptosis in renal parenchymal cells, but not in hematopoietic cells, played predominant roles in this process. We further showed that HMGB1 released from pyroptotic RTCs amplified inflammatory responses, which critically contributed to renal fibrogenesis. Specific deletion of Hmgb1 in RTCs alleviated caspase11 and IL-1ß activation in macrophages. Collectively, our results uncovered that TNFα/Casp3/GSDME-mediated pyroptosis is responsible for the initiation of ureteral obstruction-induced renal tubule injury, which subsequentially contributes to the late-stage progression of hydronephrosis, inflammation, and fibrosis. This novel mechanism will provide valuable therapeutic insights for the treatment of obstructive nephropathy.

Risk factors for renal failure and short-term prognosis in patients with spontaneous intracerebral haemorrhage complicated by acute kidney injury.

BACKGROUND: Although acute kidney injury (AKI) is a known risk factor for adverse clinical outcomes in patients with spontaneous intracerebral haemorrhage (SICH), little is known about the predisposing factors that contribute to renal failure and short-term prognosis in the setting of SICH already complicated by AKI. In this study, we aimed to identify the renal failure factors in SICH patents with AKI. METHODS: Five hundred forty-three patients with SICH complicated by differential severities of AKI who were admitted to the First Affiliated Hospital of Fujian Medical University from January 2016 to December 2018 were retrospectively studied. Logistic regression and receiver operator characteristic (ROC) curve analysis were performed to determine the best predictive and discriminative variables. Multivariate Cox regression analysis was performed to identify prognostic factors for renal recovery. RESULTS: In the multivariable adjusted model, we found that hypernatremia, metabolic acidosis, elevated serum creatine kinase, hyperuricaemia, proteinuria, and the use of colloids and diuretics were all independent risk factors for the occurrence of stage 3 AKI in SICH patients. The area under the curve analysis indicated that hypernatremia and hyperuricaemia were predictive factors for stage 3 AKI, and the combination of these two parameters increased their predictability for stage 3 AKI. Kaplan-Meier survival curves revealed that the renal recovery rate in SICH patients with stages 1 and 2 AKI was significantly higher than that in SICH patients with stage 3 AKI. Multivariate Cox regression analysis suggested that hypernatremia and the occurrence of stage 3 AKI are predictors for poor short-term renal recovery. CONCLUSIONS: These findings illustrate that hypernatremia and hyperuricaemia represent potential risk factors for the occurrence of stage 3 AKI in SICH patients. Those patients with hypernatremia and stage 3 AKI were associated with a poor short-term prognosis in renal recovery.

RIPK3 collaborates with GSDMD to drive tissue injury in lethal polymicrobial sepsis.

Sepsis is a systemic inflammatory disease causing life-threatening multi-organ dysfunction. Accumulating evidences suggest that two forms of programmed necrosis, necroptosis and pyroptosis triggered by the pathogen component lipopolysaccharide (LPS) and inflammatory cytokines, play important roles in the development of bacterial sepsis-induced shock and tissue injury. Sepsis-induced shock and tissue injury required receptor-interacting protein kinase-3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL) phosphorylation, caspase11 activation and gasdermin D (GSDMD) cleavage. However, the synergistic effect of necroptosis and pyroptosis in the pathological progress of sepsis remains elusive. In this study, we found that blockage of both necroptosis and pyroptosis (double deletion of Ripk3/Gsdmd or Mlkl/Gsdmd) resulted in accumulative protection against septic shock, systemic blood clotting and multi-organ injury in mice. Bone marrow transplantation confirmed that necroptosis and pyroptosis in both myeloid and nonmyeloid cells are indispensable in the progression of sepsis-induced multi-organ injury. Both RIPK3 and GSDMD signaling collaborated to amplify necroinflammation and tissue factor release in macrophages and endothelial cells, which led to tissue injury. Furthermore, cell death induced by inflammatory cytokines and high-mobility group box 1 could be prevented by double ablation of Ripk3/Gsdmd or Mlkl/Gsdmd, suggesting that a positive feedback loop interconnecting RIPK3/MLKL and GSDMD machinery and inflammation facilitated sepsis progression. Collectively, our findings demonstrated that RIPK3-mediated necroptosis and GSDMD-mediated pyroptosis collaborated to amply inflammatory signaling and enhance tissue injury in the process of sepsis, which may shed new light on two potential targets of combined therapeutic interventions for this highly lethal disorder.

RIPK3-MLKL-mediated necroinflammation contributes to AKI progression to CKD.

Necroptosis predominates functionally over apoptosis in the pathophysiology of renal ischemia-reperfusion injury (IRI). Inhibition of the core components of the necroptotic pathway-receptor-interacting protein kinase 1 (RIPK1), RIPK3 or mixed lineage kinase domain-like protein (MLKL) reduced renal injury after ischemia/reperfusion (IR). Necrosis can initiate inflammation, which enhances necrosis in a positive feedback loop, subsequently leading to triggering more inflammation, termed as necroinflammation. However, the mechanisms underlying necroinflammation driven by renal tubular cell necroptosis in progression of AKI to CKD are still largely unknown. Here we showed that the upregulated expression and interactions between RIPK3 and MLKL induced necroptosis of renal proximal tubular cells and contributed to NLRP3 inflammasome activation under the conditions of IRI. Gene deletion of Ripk3 or Mlkl ameliorated renal tubular cell necroptosis, macrophage infiltration and NLRP3 inflammasome activation with a reduction in caspase-1 activation and maturation of IL-1ß, and then finally reduced interstitial fibrogenesis in the long term after IRI. Bone marrow chimeras confirmed that RIPK3-MLKL-dependent necroptosis is responsible for the initiation of the early renal injury after IRI, and then necroptosis triggered NLRP3 inflammasome activation, which subsequently accelerates necroptosis and triggers more inflammation in an auto-amplification loop. These data indicate that necroinflammation driven by RIPK3-MLKL-dependent necroptosis plays a crucial role in the progression of IRI to CKD.

Interstitial complement C3 activation and macrophage infiltration in patients with hypertensive nephropathy
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BACKGROUND: The interplay between interstitial complement C3 activation and macrophage infiltration might play an important role in the pathogenesis of hypertensive nephropathy (HN), but human data are limited. We sought to investigate interstitial complement C3 expression and macrophage infiltration in HN as well as the relationships between C3 activation and macrophage infiltration, their association with clinicopathologic data, and changes in renal function. MATERIALS AND METHODS: Using immunohistochemistry, we analyzed 20 renal tissue specimens from HN patients and 40 control specimens for complement C3, angiotensin (AGT), angiotensin II, and macrophage marker CD68 levels. Serum creatinine levels, estimated glomerular filtration rate (eGFR), annual rates of change in eGFR, and the interstitial fibrosis, glomerulosclerosis, and arteriolar lesion scores were recorded. RESULTS: Patients with HN showed elevated levels of interstitial C3 expression, AGT, angiotensin II, and interstitium-infiltrating macrophages compared to controls. The enhanced interstitial expression of C3 was correlated significantly with interstitial macrophage density, serum creatinine level as well as interstitial fibrosis, glomerulosclerosis, and arteriolar lesion scores, but was inversely correlated with eGFR and annual rates of change in eGFR. CONCLUSION: In human HN, inflammation involving complement C3 activation and macrophage infiltration as well as interactions between them, may play important roles in the pathogenesis and progression of interstitial fibrosis and kidney damage.
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Bone marrow-derived mesenchymal stem cells ameliorate nephrosis through repair of impaired podocytes.

PURPOSE: The purpose of this study was to investigate the effects of bone marrow-derived mesenchymal stem cells (BMSC) on podocytes of puromycin amino nuclear glucoside (PAN) -induced nephrosis in mice. METHODS: Mice were randomly divided into Control, PAN and BMSC groups. Mice were injected with PAN (0.5 mg/g weight) via the tail vein. The 24-h urinary protein was obtained after modelling, and urinary protein excretion was determined. The blood and kidney specimens were isolated after the tenth day of modelling. Blood samples were collected for measuring serum creatinine (SCr) and blood urea nitrogen (BUN). A sample of kidney was taken for observing pathological changes through hematoxylin-eosin staining and electron microscopy, and the rest of the kidney was used for detecting the protein and mRNA expression of nephrin, CD2AP, synaptopodin, TRPC6 by real-time quantitative PCR, Western-blot and immunohistochemistry. RESULTS: After PAN injection, podocyte foot process fusion was detected by electron microscopy, and the 24 h urinary protein excretion increased compared with control mice on days 3, 7 and 10 post-PAN injection (P.

Role of complement 3 in TNF-α-induced mesenchymal transition of renal tubular epithelial cells in vitro.

Injured renal tubular epithelial cells (RTECs) have been recently thought to directly contribute to the accumulation of myofibroblasts in renal tubulointerstitial fibrosis through a process of epithelial to mesenchymal transition (EMT). However, the factors inducing RTECs to undergo EMT and the underlying mechanisms need to be further elucidated. This study aimed to determine the EMT-inducing activity of proinflammatory cytokine TNF-α and the role for complement 3 (C3) in this activity in an in vitro model of human RTECs (HK-2 cells). Wild type HK-2 cells were treated with TNF-α, IFN-γ or C3a; C3 siRNA- or control siRNA-carrying HK-2 cells were treated with TNF-α. Changes in the cell morphology and phenotype were assessed by microscopy, RT-PCR, western blotting, and immunostaining. TNF-α effectively induced HK-2 cells to express C3 and to transform into morphologically myofibroblast-like cells that lost E-cadherin (a classical epithelial cell marker) expression but acquired alpha-smooth muscle actin (α-SMA, a classical myofibroblast differentiation marker) expression. C3 siRNA robustly attenuated all the morphologic and phenotypic changes induced by TNF-α but the control siRNA showed no effect. Our preliminary observations suggest that TNF-α may induce EMT in RTECs through inducing C3 expression.

Bone marrow-derived mesenchymal stem cells differentiation into tubular epithelial-like cells in vitro.

The possibility of differentiating bone marrow-derived mesenchymal stem cells (BMSCs) into tubular epithelial-like cells is explored in vitro. Purified BMSCs from Sprague-Dawley rats were obtained by density gradient centrifugation. Third generation BMSCs were divided into six groups and were cultured under different conditions. The expression of alkaline phosphatase and cytokeratin (CK)-18 protein was detected through staining and immunocytochemistry, respectively, and the expression of E-cadherin proteins was recorded through immunofluorescence. Some cells in ischemia/reperfusion (I/R), all-trans retinoic acid (ATRA), epidermal growth factor (EGF) and bone morphogenetic protein-7 (BMP-7) groups turned positive, whereas the positive cells in the combined group significantly increased compared with the other groups. Compared with the control group, the positive expression rates of CK-18 in the I/R, ATRA, EGF, BMP-7 and the combined group were 11·50% ± 3·84%, 27·40% ± 2·70%, 29·60% ± 4·51%, 26·80% ± 5·00% and 44·00% ± 3·16%, respectively, and CK-18 mRNA expression in the combined group was obviously higher than that in the other groups (P < 0·01). Immunofluorescence detection showed that E-cadherin expression was not detectable in the control group, whereas the positive expression rates of E-cadherin in the I/R, ATRA, EGF, BMP-7 and the combined group were 6·75% ± 2·13%, 16·40% ± 2·69%, 18·25% ± 3·50%, 16·06% ± 2·00% and 30·26% ± 5·16%, respectively. The addition of ATRA, EGF and BMP-7 induces BMSCs differentiation into tubular epithelial-like cells in stimulated acute renal failure microenvironment in vitro.