Interstitial Fibrosis Research Articles

SFN promotes renal fibrosis via binding with MYH9 in chronic kidney disease

Chronic kidney disease (CKD) is a clinical syndrome characterized by persistent renal function decline. Renal fibrosis is the main pathological process in CKD, but an effective treatment does not exist. Stratifin (SFN) is a highly-conserved, multi-function soluble acidic protein. Therefore, this study explored the effects of SFN on renal fibrosis. First, we found that SFN was highly expressed in patients with CKD, as well as in renal fibrosis animal and cell models. Next, transforming growth factor-beta 1 (TGF-β1) induced injury and fibrosis in human renal tubule epithelial cells, and SFN knockdown reversed these effects. Furthermore, SFN knockdown mitigated unilateral ureteral obstruction (UUO)-induced renal tubular dilatation and renal interstitial fibrosis in mice. Liquid chromatography-tandem mass spectrometry/mass spectrometry (LC-MS/MS), co-immunoprecipitation (Co-IP), and immunofluorescence co-localization assays demonstrated that SFN bound the non-muscle myosin-encoding gene, myosin heavy chain 9 (MYH9), in the cytoplasm of renal tubular epithelial cells. MYH9 knockdown also reduced Col-1 and α-SMA expression, which are fibrosis markers. Finally, silencing SFN decreased MYH9 expression, alleviating renal fibrosis. These results suggest that SFN promotes renal fibrosis in CKD by interacting with MYH9. This study may provide potential strategies for the treatment of CKD.

Aberrant proximal tubule DNA methylation underlies phenotypic changes related to kidney dysfunction in patients with diabetes.

Epigenetic mechanisms are considered to contribute to diabetic nephropathy by maintaining memory of poor glycemic control during the early stages of diabetes. However, DNA methylation changes in the human kidney are poorly characterized, because of the lack of cell type-specific analysis. We examined DNA methylation in proximal tubules purified from diabetic nephropathy patients and identified differentially methylated CpG sites, given the critical role of proximal tubules in the kidney injury. Hypermethylation was observed at CpG sites annotated to genes responsible for proximal tubule functions, including gluconeogenesis, nicotinamide adenine dinucleotide synthesis, transporters of glucose, water, phosphate, and drugs, in diabetic kidneys, while genes involved in oxidative stress and the cytoskeleton exhibited demethylation. Methylation levels of CpG sites annotated to ACTN1, BCAR1, MYH9, UBE4B, AFMID, TRAF2, TXNIP, FOXO3, and HNF4A were correlated with the estimated glomerular filtration rate, while methylation of the CpG site in RUNX1 was associated with interstitial fibrosis and tubular atrophy. Hypermethylation of G6PC and HNF4A was accompanied by decreased expression in diabetic kidneys. Proximal tubule-specific hypomethylation of metabolic genes related to HNF4A observed in control kidneys was compromised in diabetic kidneys, suggesting a role for aberrant DNA methylation in the dedifferentiation process. Multiple genes with aberrant DNA methylation in diabetes overlapped genes with altered expressions in maladaptive proximal tubule cells, including transcription factors PPARA and RREB1. In conclusion, DNA methylation derangement in the proximal tubules of patients with diabetes may drive phenotypic changes, characterized by inflammatory and fibrotic features, along with impaired function in metabolism and transport.

Assessment of Probability of Pulmonary Fibrosis Progression in Patients with Interstitial Lung Diseases to Determine Further Treatment Tactics

The objective: to develop a method for assessing the probability of progression of pulmonary fibrosis in patients with interstitial lung diseases in order to determine further treatment tactics.Subjects and Methods. 80 patients with interstitial lung diseases underwent lung biopsies with consequent morphological and immunohistochemical tests. The group with progressive fibrosis consisted of 42 patients. The prognostic model was built using the binary logistic regression method.Results. A statistical model was developed in the form of a regression equation consisting of 3 parameters: the presence of a morphological pattern of interstitial fibrosis; intensity of CTGF expression; and intensity of TGF-β expression. This mathematical model makes it possible to predict the progression of pulmonary fibrosis in patients with interstitial lung diseases with 83.3% sensitivity and 84.2% specificity.

Elevated myocardial extracellular volume fraction is associated with the development of conduction pathway defects following transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) has become an established method of aortic stenosis treatment but suffers from the risk of heart block and pacemaker requirement. Risk stratification for patients who may develop heart block remains imperfect. Simultaneously, myocardial fibrosis as measured by cardiac magnetic resonance imaging (CMR) has been demonstrated as a prognostic indicator of ventricular recovery and mortality following TAVR. However, the association of CMR-based measures of myocardial fibrosis with post-TAVR conduction disturbances has not yet been explored. We evaluated whether myocardial fibrosis, as measured by late gadolinium enhancement and extracellular volume (ECV) from CMR would be associated with new conduction abnormalities following TAVR. One hundred seventy patients who underwent CMR within 2 months before TAVR were retrospectively reviewed. Septal late gadolinium enhancement (LGE) and ECV measurements were made as surrogates for replacement and interstitial fibrosis respectively. New conduction abnormalities were defined by the presence of transient or permanent atrioventricular block, new bundle branch blocks, and need for permanent pacemaker. Association of myocardial fibrosis and new conduction derangements were tested using receiver operator curve (ROC) and regression analysis in patients with and without pre-existing conduction issues. Forty-six (27.1%) patients developed post-TAVR conduction deficits. ECV was significantly higher among patients who experienced new conduction defects (26.2 ± 3.45% vs. 24.7% ± 4.15%, p value: 0.020). A greater fraction of patients that had new conduction defects had an elevated ECV of ≥26% (54.3% vs. 36.3%, p value: 0.026). ECV ≥ 26% was independently associated with the development of new conduction defects (odds ratio [OR]: 2.364, p value: 0.030). ROC analysis revealed a significant association of ECV with new conduction defects with an area under the receiver operating characteristic curve (AUC) of 0.632 (95% confidence interval: 0.555-0.705, p value: 0.005). The combination of prior right bundle branch block (RBBB) and ECV revealed a greater AUC of 0.779 (0.709-0.839, p value: <0.001) than RBBB alone (Delong p value: 0.049). No association of LGE/ECV with new conduction defects was observed among patients with pre-existing conduction disease. Among patients without baseline conduction disease, ECV was independently associated with the development of new conduction deficits (OR: 3.685, p value: 0.008). The present study explored the association of myocardial fibrosis, as measured by LGE and ECV with conduction deficits post-TAVR. Our results demonstrate an association of ECV, and thereby interstitial myocardial fibrosis, with new conduction derangement post-TAVR and introduce ECV as a potentially new risk stratification tool to identify patients at higher risk for needing post-TAVR surveillance and/or permanent pacemaker.

DNA methylation of miR-181a-5p mediated by DNMT3b drives renal interstitial fibrosis developed from acute kidney injury.

Aim: To explore the role of miR-181a-5p in the progression of acute kidney injury (AKI) to renal interstitial fibrosis (RIF) from the perspective of DNA methylation.Materials & methods: The role of miR-181a-5p was confirmed by collecting clinical samples, injecting miR-181a-5p agomir into tail vein, and transfecting miR-181a-5p mimic in vitro. The mechanism of miR-181a-5p's influence on AKI induced RIF was investigated by methylation-specific PCR, bioinformatic analysis, transcriptome sequencingand so on.Results: MiR-181a-5p plays an important role in AKI induced RIF. DNMT3b-mediated miR-181a-5p promoter hypermethylation is the main reason for the downregulation of miR-181a-5p. HDAC9 and SNAI2 are direct targets of miR-181a-5p.Conclusion: Hypermethylation of miR-181a-5p promoter mediated by DNMT3b promotes AKI induced RIF by targeting HDAC9 and SNAI2.

The pathogenic mechanism of monosodium urate crystal-induced kidney injury in a rat model.

(MSU) crystals usually in the kidney tubules especially collecting ducts in the medulla. Previous animal models have not fully reproduced the impact of MSU on kidneys under non-hyperuricemic conditions. In the group treated with MSU, the upper pole of the rat kidney was injected intrarenally with 50 mg/kg of MSU, while the lower pole was injected with an equivalent volume of PBS solution. The body weight and kidney mass of the rats were observed and counted. H&E staining was used to observe the pathological damage of the kidney and to count the number of inflammatory cells. Masoon staining was used to observe the interstitial fibrosis in the kidneys of the rat model. Flow cytometric analysis was used for counting inflammatory cells in rats. ElISA was used to measure the concentration of serum and urine uric acid, creatinine and urea nitrogen in rats. At the MSU injection site, a significantly higher infiltration of inflammatory cells and a substantial increase in the area of interstitial fibrosis compared to the control group and the site of PBS injection were observed. The serum creatinine level was significantly increased in the MSU group. However, there were no significant differences in the rats' general conditions or blood inflammatory cell counts when compared to the control group. The injection of urate crystals into the kidney compromised renal function, caused local pathological damage, and increased inflammatory cell infiltration and interstitial fibrosis. Intrarenal injection of MSU crystals may result in urate nephropathy. The method of intrarenal injection did not induce surgical infection or systemic inflammatory response.

Left Ventricular Fibrosis by Cardiac Magnetic Resonance Tissue Characterization in Chronic Mitral Regurgitation Patients.

Background: Left ventricular remodeling in chronic mitral regurgitation (MR) encompasses two types of myocardial fibrosis: replacement fibrosis, identified by late gadolinium enhancement (LGE), and diffuse interstitial fibrosis, assessed by pre- and postcontrast T1 mapping techniques. These may explain irreversible LV dysfunction after MR correction. We aimed to assess the presence of myocardial fibrosis in patients with moderate and severe MR with no criteria for surgery versus mild MR controls. Methods: We enrolled 137 patients with chronic primary MR and 130 controls; all underwent cardiac magnetic resonance, and were followed up in a median of 2.9 years to assess mortality and the need for mitral valve replacement. Results: Patients in the study group displayed significantly higher degrees of LGE (28.4% vs 7.69%, p < 0.05), higher native T1 values (1167 ± 58.5 versus 971 ± 51.4 (p < 0.05)), and higher extracellular volumes compared to controls (32.3% ± 3.5 versus 23.9 ± 2.2, (p < 0.05)). The composite outcome occurred in 28 patients in the study group (20.4%), and significantly higher with LGE+ (78.5%). Replacement fibrosis (HR = 1.83, 95% CI, p < 0.01) and interstitial fibrosis (HR = 1.61, 95% CI, p < 0.01) were independent predictors for the composite outcome. Conclusions: Patients with moderate and severe MR with no criteria for surgery still exhibit a significant degree of both replacement and interstitial fibrosis, with prognostic implications.

Role of TSP-1 and its receptor ITGB3 in the renal tubulointerstitial injury of focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS), a common cause of primary glomerulonephritis, has a poor prognosis and is pathologically featured by tubulointerstitial injury. Thrombospondin-1 (TSP-1) is an extracellular matrix protein that acts in combination with different receptors in the kidney. Here, we analyzed the tubular expression of TSP-1 and its receptor integrin β3 (ITGB3) in FSGS. Previously the renal interstitial chip analysis of FSGS patients with tubular interstitial injury showed that the expressions of TSP-1 and ITGB3 were up-regulated. We found that the level of TSP-1 and ITGB3 increased in the tubular cells of FSGS patients. The serum level of TSP-1 increased and was correlated to the degree of tubulointerstitial lesions in FSGS patients. THBS1/ITGB3 signaling induced renal tubular injury in HK-2 cells exposure to BSA and the ADR-induced nephropathy model. THBS1 knockout ameliorated tubular injury and renal fibrosis in ADR-treated mice. THBS1 knockdown decreased the expression of KIM-1 and caspase 3 in the HK-2 cells treated with BSA, while THBS1 overexpression could induce tubular injury. In vivo, we identified cyclo-RGDfK as an agent to block the binding of TSP-1 to ITGB3. Cyclo-RGDfK treatment could alleviate ADR-induced renal tubular injury and interstitial fibrosis in mice. Moreover, TSP-1 and ITGB3 were colocalized in tubular cells of FSGS patients and ADR-treated mice. Taken together, our data showed that TSP-1/ITGB3 signaling contributed to the development of renal tubulointerstitial injury in FSGS, potentially identifying a new therapeutic target for FSGS.

Fasting alleviates bleomycin-induced lung inflammation and fibrosis via decreased Tregs and monocytes

PurposeIdiopathic pulmonary fibrosis (IPF), a chronic and progressively worsening condition characterized by interstitial lung inflammation and fibrosis of unknown etiology, has a grim prognosis. The treatment options for IPF are limited and new therapeutic strategies are urgently needed. Dietary restriction can improve various inflammatory diseases, but its therapeutic effect on bleomycin (BLM)-induced pulmonary fibrosis mouse model remains unclear. This study aims to investigate whether intermittent fasting (IF) can alleviate BLM-induced pulmonary inflammation and fibrosis. MethodsPulmonary fibrosis mouse models were induced by BLM. The IF group underwent 24-hour fasting cycles for one week prior and three weeks following BLM administration. Meanwhile, the ad libitum feeding group had unrestricted access to food throughout the experiment. The evaluation focused on lung pathology via histological staining, qPCR analysis of collagen markers, and immune cell profiling through flow cytometry. ResultsIF group significantly reduced inflammation and fibrosis in lung tissues of BLM-induced mice compared to ad libitum feeding group. qPCR results showed IF remarkably decreased the mRNA expression of Col 1a and Col 3a in the lungs of BLM-induced mouse models. IF also reduced the numbers of regulatory T cells (Tregs), T helper 17 (Th17) cells, monocytes, and monocyte-derived alveolar macrophages (MoAMs) in the lung tissues. ConclusionsIF may improve BLM-induced pulmonary fibrosis by decreasing numbers of immune cells including Treg cells, Th17 cells, monocytes, and MoAMs in the lungs. This study offers experimental validation for dietary intervention as a viable treatment modality in IPF management.

Outcomes of Early Thrombotic Microangiopathy in Renal Transplantation.

Alternate complement dysregulation postrenal transplantation can result in thrombotic microangiopathy (TMA). There is a scarcity of data regarding outcomes based on the timing of TMA post-transplant, coupled with a lack of follow-up biopsy findings post TMA diagnosis. This study aims to assess allograft and patient outcomes in individuals developing early TMA, defined within 4months post-transplantation, and explore any differences in follow-up surveillance biopsies compared to a non-TMA group. This is a single center retrospective study between January 1, 2002 and October 10, 2019. Patients who developed TMA within 4months post-transplantation were compared to a propensity matched non-TMA group. Thirty-one patients developed TMA within 4months of renal transplantation. Index TMA biopsy featured noticeable glomerular, and vascular lesions along with acute tubular injury. Four-month surveillance biopsy showed significant glomerulitis, transplant glomerulopathy and chronic interstitial fibrosis as compared to non-TMA group. However, at 1year, these differences were no longer significant. There was no significant difference in patient survival (TMA vs. non-TMA, p=0.083); however, death censored graft survival was significantly lower in the TMA group (p<0.001). TMA patients had a significantly lower estimated glomerular filtration rate at 4months and at 1year as compared to the non-TMA group. Early onset TMA post renal transplant leads to decreased renal function and lower graft survival. Early recognition and prompt treatment may help in reducing the adverse outcomes.

Src inhibition modulates AMBRA1-mediated mitophagy to counteract endothelial-to-mesenchymal transition in renal allograft fibrosis.

Chronic allograft dysfunction (CAD) poses a significant challenge in kidney transplantation, with renal vascular endothelial-to-mesenchymal transition (EndMT) playing a vital role. While renal vascular EndMT has been verified as an important contributing factor to renal allograft interstitial fibrosis/tubular atrophy in CAD patients, its underlying mechanisms remain obscure. Currently, Src activation is closely linked to organ fibrosis development. Single-cell transcriptomic analysis in clinical patients revealed that Src is a potential pivotal mediator in CAD progression. Our findings revealed a significant upregulation of Src which closely associated with EndMT in CAD patients, allogeneic kidney transplanted rats and endothelial cells lines. In vivo, Src inhibition remarkably alleviate EndMT and renal allograft interstitial fibrosis in allogeneic kidney transplanted rats. It also had a similar antifibrotic effect in two endothelial cell lines. Mechanistically, the knockout of Src resulted in an augmented AMBRA1-mediated mitophagy in endothelial cells. We demonstrate that Src knockdown upregulates AMBRA1 level and activates mitophagy by stabilizing Parkin's ubiquitination levels and mitochondrial translocation. Subsequent experiments demonstrated that the knockdown of the Parkin gene inhibited mitophagy in endothelial cells, leading to increased production of Interleukin-6, thereby inducing EndMT. Consequently, our study underscores Src as a critical mediator of renal vascular EndMT and allograft interstitial fibrosis, exerting its impact through the regulation of AMBRA1/Parkin-mediated mitophagy.

Hydrogen combined with tetrandrine attenuates silica-induced pulmonary fibrosis via suppressing NF-kappaB/NLRP3 signaling pathway-mediated epithelial mesenchymal transition and inflammation

Silicosis is a progressive disease characterized by interstitial fibrosis resulting from inhalation of silica particles, and currently lacks specific treatment. Hydrogen (H2) has demonstrated antioxidative, anti-inflammatory, and anti-fibrotic properties, yet its efficacy in treating silicosis remains unexplored. In this study, rats exposed to silica were administered interventions of H2 combined with tetrandrine, and euthanized at 14, 28, and 56 days post-intervention. Lung tissues and serum samples were collected for analysis. Histological examination, MDA assay, enzyme-linked immunosorbent assay, hydroxyproline assay, and Western blotting were employed to assess the impact of H2 combined with tetrandrine on pulmonary fibrosis. The results revealed that this combination significantly alleviated inflammation in silicosis-afflicted rats, effectively suppressed levels of MDA, TNF-α, and IL-1β expression, and inhibited epithelial-mesenchymal transition (EMT), thereby ameliorating pulmonary fibrosis. Notably, protein expression level of E-cadherin was increased，however protein expression levels of vimentin and α-SMA were reduced, and TGF-β were reduced, alongside a significant decrease in hydroxyproline content. Furthermore, H2 combined with tetrandrine downregulated protein expression of NF-κB p65, NF-κB p-p65, Caspase-1, ASC, and NLRP3. These findings substantiate the hypothesis that H2 combined with tetrandrine mitigates inflammation associated with silicosis and suppresses the EMT process to ameliorate fibrosis via the NF-κB/NLRP3 signaling pathway. However, the pressure of airway opening was not assessed in this study and dynamic readings of lung physiological function were not obtained, which is a major limitation of this study.

Early Detection of Cardiotoxicity Using [64Cu]Cu-NODAGA-E[(cRGDyK)]2 PET Imaging in a Rat Model of Doxorubicin-Induced Heart Failure.

Doxorubicin (DOX) is a common and highly effective chemotherapeutic. However, its use is limited by cardiotoxic effects and the lack of methods to detect these at early time points. In the present study, we evaluated if [64Cu]Cu-NODAGA-E[(cRGDyK)]2 positron emission tomography-computed tomography ([64Cu]Cu-RGD PET/CT) could detect cardiotoxicity in a rat model of DOX-induced heart failure. Male Lewis rats were divided into two groups and treated with either a cumulative dose of 15 mg/kg of DOX or left untreated. Cardiac anatomy and function were assessed using magnetic resonance imaging at baseline and in week 8. [64Cu]Cu-RGD PET/CT scans were performed in week 4. DOX treatment led to a decline in pump function as well as an increase in cardiac and thymic uptake of [64Cu]Cu-RGD. In addition, DOX altered cardiac gene expression, led to infiltration of immune cells, reduced endothelial content, and increased interstitial fibrosis. Furthermore, concentrations of inflammatory plasma proteins were increased in the DOX group. In conclusion, DOX treatment resulted in the development of cardiotoxicity and heart failure, which could be detected using [64Cu]Cu-RGD PET/CT at early time points. [64Cu]Cu-RGD uptake in the myocardial septum and thymus predicted a low left ventricular ejection fraction in week 8.

Promoting renal I/R injury repair by in-situ electric stimulation using biodegradable piezoelectric polylactide/vitamin B2 composite nanofibrous membrane

Ischemia/reperfusion (I/R) injury during renal transplantation remains a prevalent challenge. Recent studies proposed protective effects against renal I/R injury using electric fields during organ preservation stage. However, I/R process extends to the post reperfusion stage and traditional electrical stimulation methods face limitations, requiring power sources and electrodes. Hence, there is a need for implantable, biodegradable materials capable of continuously generating electrical stimulation to treat kidney I/R injury over an extended period. In this work, a polylactide/Vitamin B2 (PLLA/VB2) composite nanofibrous membrane was designed. The incorporation of VB2 into PLLA, coupled with electrospinning, significantly enhanced its piezoelectric performance and flexibility, thereby enabling optimal adherence and efficient in-situ electrical stimulation. Experimental results underscored that PLLA/VB2 nanofibrous membrane could mitigate tubular injury, facilitate cell regeneration, and alleviate interstitial fibrosis possibly by preserving mitochondrial structure and function. This innovative approach not only pioneers new strategies for addressing I/R related conditions but also offers potential treatments for a range of diseases linked to oxidative stress.

From diverticulosis to complicated diverticular disease: Progression of myogenic alterations and oxidative imbalance.

The natural history and pathophysiology of diverticular disease (DD) are still uncertain. An ex-vivo human complicated DD (cDD) model has recently shown a predominant transmural oxidative imbalance. The present study aims to evaluate whether the previously described alterations may precede the symptomatic form of the disease. Colonic surgical samples obtained from patients with asymptomatic diverticulosis (DIV), complicated DD, and controls were systematically and detailed morphologically and molecularly analyzed. Therefore, histologic, histomorphometric, immunohistochemical evaluation, and gene and protein expression analysis were performed to characterize colonic muscle changes and evaluate chronic inflammation, oxidative imbalance, and hypoxia. Functional muscle activity was tested on strips and isolated cells in response to contractile and relaxant agents. Compared with controls, DD showed a marketed increase in muscle layer thickness, smooth muscle cell syncytium disarray, and increased interstitial fibrosis; moreover, the observed features were more evident in the cDD group. These changes mainly affected longitudinal muscle and were associated with altered contraction-relaxation dynamics and fibrogenic switch of smooth muscle cells. Chronic lymphoplasmacytic inflammation was primarily evident in the mucosa and spared the muscle. A transmural increase in carbonylated and nitrated proteins, with loss of antioxidant molecules, characterized both stages of DD, suggesting early oxidative stress probably triggered by recurrent ischemic events, more pronounced in cDD, where HIF-1 was detected in both muscle and mucosa. The different DD clinical scenarios are part of a progressive process, with oxidative imbalance representing a new target in the management of DD.

Crohn's disease-associated IgA nephropathy may prone to better renal outcome.

Renal involvement in Crohn's Disease (CD) was rare in the population. Little was known between IgA nephropathy and CD. This study aimed to investigate the differences in clinical and outcome features of CD-associated IgA nephropathy (CD-IgAN)and primary IgA nephropathy (PIgAN). Clinical data of patients diagnosed with IgAN by kidney biopsy were collected in the Sixth Affiliated Hospital of Sun Yat-sen University from January 1st, 2016 to June 1st, 2023. 17 patients with CD-IgAN and 87 patients with PIgAN were enrolled in this retrospective study. Compared with PIgAN patients, CD-IgAN patients had lower levels of urinary protein excretion (1.57g per 24h vs. 0.33g per 24h, p < 0.01), but higher levels of estimated glomerular filtration rate (77.63 ± 40.11ml per min per 1.73m2 vs. 104.53 ± 32.97ml per min per 1.73m2, p = 0.008). From the point of renal pathology of PIgAN, patients with CD-IgAN had a less incidence of tubular atrophy or interstitial fibrosis (p = 0.001). CD-IgAN patients had a higher incidence of complete remission of proteinuria (45.8% vs. 81.8%, p = 0.031) or hematuria (10.4% vs. 45.4%, p = 0.019) than PIgAN patients after twelve-month treatments. CD-IgAN manifests a milder progression of renal function than those PIgAN. After the treatment, proteinuria or hematuria are more prone to remit in patients with CD-IgAN.

Assessing renal interstitial fibrosis using compartmental, non-compartmental, and model-free diffusion MRI approaches

ObjectiveTo assess renal interstitial fibrosis (IF) using diffusion MRI approaches, and explore whether corticomedullary difference (CMD) of diffusion parameters, combination among MRI parameters, or combination with estimated glomerular filtration rate (eGFR) benefit IF evaluation.MethodsForty-two patients with chronic kidney disease were included, undergoing MRI examinations. MRI parameters from apparent diffusion coefficient (ADC), intra-voxel incoherent motion (IVIM), diffusion kurtosis imaging (DKI), and diffusion-relaxation correlated spectrum imaging (DR-CSI) were obtained both for renal cortex and medulla. CMD of these parameters was calculated. Pathological IF scores (1–3) were obtained by biopsy. Patients were divided into mild (IF = 1, n = 23) and moderate-severe fibrosis (IF = 2–3, n = 19) groups. Group comparisons for MRI parameters were performed. Diagnostic performances were assessed by the receiver operator’s curve analysis for discriminating mild from moderate-severe IF patients.ResultsSignificant inter-group differences existed for cortical ADC, IVIM-D, IVIM-f, DKI-MD, DR-CSI VB, and DR-CSI VC. Significant inter-group differences existed in ΔADC, ΔMD, ΔVB, ΔVC, ΔQB, and ΔQC. Among the cortical MRI parameters, VB displayed the highest AUC = 0.849, while ADC, f, and MD also showed AUC > 0.8. After combining cortical value and CMD, the diagnostic performances of the MRI parameters were slightly improved except for IVIM-D. Combining VB with f brings the best performance (AUC = 0.903) among MRI bi-variant models. A combination of cortical VB, ΔADC, and eGFR brought obvious improvement in diagnostic performance (AUC 0.963 vs 0.879, specificity 0.826 vs 0.896, and sensitivity 1.000 vs 0.842) than eGFR alone.ConclusionOur study shows promising results for the assessment of renal IF using diffusion MRI approaches.Critical relevance statementOur study explores the non-invasive assessment of renal IF, an independent and effective predictor of renal outcomes, by comparing and combining diffusion MRI approaches including compartmental, non-compartmental, and model-free approaches.Key PointsSignificant difference exists for diffusion parameters between mild and moderate-severe IF.Generally, cortical parameters show better performance than corresponding CMD.Bi-variant model lifts the diagnostic performance for assessing IF.Graphical

C4d expression in focal segmental glomerulosclerosis

BackgroundThere is a little information about of expression of C4d (complement fragment) in Focal segmental glomerulosclerosis (FSGS) subtypes. Our aim was to determine the expression of C4d in FSGS subtypes in percutaneous native renal biopsies in a second-level hospital and its correlation with clinical, biochemical and histological variables. Material and methodsA retrospective study in paraffin blocks of patients with biopsy with FSGS aged 16–65 years, indistinct sex, not diabetic or obese. Immunohistochemistry was performed for C4d and their expression was analyzing in non-sclerosed glomerular capillaries (GC) and sclerosis areas (SA). Clinical and biochemical variables were recorded. The cases were divided into C4d positive and C4d negative groups and compared. The correlation between C4d staining scores in CG and SA with clinical and biochemical variables were analyzed. ResultsTwenty samples were analyzed, 4 for each subtype. At the time of biopsy average age 38.8 ± 18.6 years, 65% male, 8.7% were hypertension. The percentage of positivity for C4d was 40% in GC, 30% SA and 35% in mesangium. The highest expression was for cellular and collapsing subtypes. C4d positivity cases had increased proteinuria (p = 0.035). A significant correlation was found between percentage of C4d expression in CG with SA (p = 0.012) and SA with tubular atrophy and interstitial fibrosis (p < 0.05). ConclusionsC4d expression in FSGS predominated in the cellular and collapsing subtypes, which translates complement activation. C4d is a possible surrogate marker in GSFS.

Banff 2022 Kidney Commentary: Reflections and Future Directions.

In September 2022, in Banff, Alberta, Canada, the XVIth Banff meeting, corresponding to the 30th anniversary of the Banff classification, was held, leading to 2 recent publications. Discussions at the Banff meeting focused on proposing improvements to the Banff process as a whole. In line with this, a unique opportunity was offered to a selected group of 16 representatives from the pathology and transplant nephrology community, experts in the field of kidney transplantation, to review these 2 Banff manuscripts. The aim was to provide an insightful commentary, to gauge any prospective influence the proposed changes may have, and to identify any potential areas for future enhancement within the Banff classification. The group expressed its satisfaction with the incorporation of 2 new entities, namely "microvascular inflammation/injury donor-specific antibodies-negative and C4d negative" and "probable antibody-mediated rejection," into category 2. These changes expand the classification, facilitating the capture of more biopsies and providing an opportunity to explore the clinical implications of these lesions further. However, we found that the Banff classification remains complex, potentially hindering its widespread utilization, even if a degree of complexity may be unavoidable given the intricate pathophysiology of kidney allograft pathology. Addressing the histomorphologic diagnosis of chronic active T cell-mediated rejection (CA TCMR), potentially reconsidering a diagnostic-agnostic approach, as for category 2, to inflammation in interstitial fibrosis and tubular atrophy and chronic active T cell-mediated rejection was also an important objective. Furthermore, we felt a need for more evidence before molecular diagnostics could be routinely integrated and emphasized the need for clinical and histologic context determination and the substantiation of its clinical impact through rigorous clinical trials. Finally, our discussions stressed the ongoing necessity for multidisciplinary decision-making regarding patient care.

Single-cell RNA transcriptomic reveal the mechanism of MSC derived small extracellular vesicles against DKD fibrosis

Diabetic kidney disease (DKD), a chronic kidney disease, is characterized by progressive fibrosis caused due to persistent hyperglycemia. The development of fibrosis in DKD determines the patient prognosis, but no particularly effective treatment. Here, small extracellular vesicles derived from mesenchymal stem cells (MSC-sEV) have been used to treat DKD fibrosis. Single-cell RNA sequencing was used to analyze 27,424 cells of the kidney, we have found that a novel fibrosis-associated TGF-β1+Arg1+ macrophage subpopulation, which expanded and polarized in DKD and was noted to be profibrogenic. Additionally, Actin+Col4a5+ mesangial cells in DKD differentiated into myofibroblasts. Multilineage ligand-receptor and cell-communication analysis showed that fibrosis-associated macrophages activated the TGF-β1/Smad2/3/YAP signal axis, which promotes mesangial fibrosis-like change and accelerates renal fibrosis niche. Subsequently, the transcriptome sequencing and LC-MS/MS analysis indicated that MSC-sEV intervention could restore the levels of the kinase ubiquitin system in DKD and attenuate renal interstitial fibrosis via delivering CK1δ/β-TRCP to mediate YAP ubiquitination degradation in mesangial cells. Our findings demonstrate the unique cellular and molecular mechanisms of MSC-sEV in treating the DKD fibrosis niche at a single-cell level and provide a novel therapeutic strategy for renal fibrosis.