Piezo ion channels: long-sought-after mechanosensors mediating hypertension and hypertensive nephropathy.

Recent advances in mechanobiology and the discovery of mechanosensitive ion channels have opened a new era of research on hypertension and related diseases. Piezo1 and Piezo2, first reported in 2010, are regarded as bona fide mechanochannels that mediate various biological and pathophysiological phenomena in multiple tissues and organs. For example, Piezo channels have pivotal roles in blood pressure control, triggering shear stress-induced nitric oxide synthesis and vasodilation, regulating baroreflex in the carotid sinus and aorta, and releasing renin from renal juxtaglomerular cells. Herein, we provide an overview of recent literature on the roles of Piezo channels in the pathogenesis of hypertension and related kidney damage, including our experimental data on the involvement of Piezo1 in podocyte injury and that of Piezo2 in renin expression and renal fibrosis in animal models of hypertensive nephropathy. The mechanosensitive ion channels Piezo1 and Piezo2 play various roles in the pathogenesis of systemic hypertension by acting on vascular endothelial cells, baroreceptors in the carotid artery and aorta, and the juxtaglomerular apparatus. Piezo channels also contribute to hypertensive nephropathy by acting on mesangial cells, podocytes, and perivascular mesenchymal cells.

MICT ameliorates hypertensive nephropathy by inhibiting TLR4/NF-κB pathway and down-regulating NLRC4 inflammasome.

BACKGROUND: Hypertensive nephropathy (HN) is one of the main causes of end-stage renal disease (ESRD), leading to serious morbidity and mortality in hypertensive patients. However, existing treatment for hypertensive nephropathy are still very limited. It has been demonstrated that aerobic exercise has beneficial effects on the treatment of hypertension. However, the underlying mechanisms of exercise in HN remain unclear. METHODS: The spontaneously hypertensive rats (SHR) were trained for 8 weeks on a treadmill with different exercise prescriptions. We detected the effects of moderate intensity continuous training (MICT) and high intensity interval training (HIIT) on inflammatory response, renal function, and renal fibrosis in SHR. We further investigated the relationship between TLR4 and the NLRC4 inflammasome in vitro HN model. RESULTS: MICT improved renal fibrosis and renal injury, attenuating the inflammatory response by inhibiting TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. However, these changes were not observed in the HIIT group. Additionally, repression of TLR4/NF-κB pathway by TAK-242 inhibited activation of NLRC4 inflammasome and alleviated the fibrosis in Ang II-induced HK-2 cells. CONCLUSION: MICT ameliorated renal damage, inflammatory response, and renal fibrosis via repressing TLR4/NF-κB pathway and the activation of NLRC4 inflammasome. This study might provide new references for exercise prescriptions of hypertension.

The Protective Effect of Vitexin on Hypertensive Nephropathy Rats.

INTRODUCTION: Vitexin is a natural flavonoid compound extracted from Vitex leaves or seeds, exhibiting various pharmacological activities including anticancer, antihypertensive, anti-inflammatory, and spasmolytic effects. However, its protective effects on hypertensive nephropathy (HN) and the underlying mechanisms remain unclear. METHODS: Spontaneous hypertension rats were fed a high-sugar and high-fat diet for 8 weeks to induce the disease HN model. From the 5th week, the rats were administered vitexin via gavage. Blood pressure was measured biweekly using the tail-cuff method. Histopathological changes were assessed using HE staining, and biochemical analyses were performed to evaluate the effects of vitexin on HN rats. The underlying mechanisms of vitexin treatment were investigated through western blotting. RESULTS: The data demonstrated that vitexin significantly lowered systolic, diastolic, and mean arterial pressures and ameliorated histopathological changes in HN rats. Biochemical analyses revealed that vitexin reduced the levels of creatinine (Cr), blood urea nitrogen (BUN), total cholesterol (TC), triglycerides (TG), total protein (TP), low-density lipoprotein cholesterol (LDL-C), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and advanced glycation end products (AGEs), while increasing the levels of albumin (ALB) and superoxide dismutase (SOD). Western blotting results indicated that vitexin treatment decreased the expression of TNF-α, IL-6, and nuclear factor kappa-B (NF-κB), while increasing the expression of SOD. CONCLUSION: The findings of this study suggest that vitexin exerts protective effects against HN, providing pharmacological evidence for its potential use in HN treatment.

Transcriptome Analysis of BAFF/BAFF-R System in Murine Nephrotoxic Serum Nephritis.

Chronic kidney disease (CKD) is an emerging cause for morbidity and mortality worldwide. Acute kidney injury (AKI) can transition to CKD and finally to end-stage renal disease (ESRD). Targeted treatment is still unavailable. NF-κB signaling is associated with CKD and activated by B cell activating factor (BAFF) via BAFF-R binding. In turn, renal tubular epithelial cells (TECs) are critical for the progression of fibrosis and producing BAFF. Therefore, the direct involvement of the BAFF/BAFF-R system to the pathogenesis of CKD is conceivable. We performed non-accelerated nephrotoxic serum nephritis (NTN) as the CKD model in BAFF KO (B6.129S2-Tnfsf13btm1Msc/J), BAFF-R KO (B6(Cg)-Tnfrsf13ctm1Mass/J) and wildtype (C57BL/6J) mice to analyze the BAFF/BAFF-R system in anti-glomerular basement membrane (GBM) disease using high throughput RNA sequencing. We found that BAFF signaling is directly involved in the upregulation of collagen III as BAFF ko mice showed a reduced expression. However, these effects were not mediated via BAFF-R. We identified several upregulated genes that could explain the effects of BAFF in chronic kidney injury such as Txnip, Gpx3, Igfbp7, Ccn2, Kap, Umod and Ren1. Thus, we conclude that targeted treatment with anti-BAFF drugs such as belimumab may reduce chronic kidney damage. Furthermore, upregulated genes may be useful prognostic CKD biomarkers.

Lymphatic System and the Kidney: From Lymphangiogenesis to Renal Inflammation and Fibrosis Development.

The lymphatic kidney system plays a crucial role in managing interstitial fluid removal, regulating fluid balance, and tuning immune response. It also assists in the reabsorption of proteins, electrolytes, cytokines, growth factors, and immune cells. Pathological conditions, including tissue damage, excessive interstitial fluid, high blood glucose levels, and inflammation, can initiate lymphangiogenesis-the formation of new lymphatic vessels. This process is associated with various kidney diseases, including polycystic kidney disease, hypertension, ultrafiltration challenges, and complications post-organ transplantation. Although lymphangiogenesis has beneficial effects in removing excess fluid and immune cells, it may also contribute to inflammation and fibrosis within the kidneys. In this review, we aim to discuss the biology of the lymphatic system, from its development and function to its response to disease stimuli, with an emphasis on renal pathophysiology. Furthermore, we explore how innovative treatments targeting the lymphatic system could potentially enhance the management of kidney diseases.

Relevance of histopathological findings for predictive scoring of short-term treatment response to plasma exchange in severe ANCA-associated renal vasculitides.

Introduction: Rapidly progressive glomerulonephritis (RPGN) is characterized by a rapid loss of kidney function, affecting both renal and overall patient survival. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small vessel vasculitis affecting multiple organ systems including the kidney, and among most frequent causes of RPGN. We here aimed to validate a recently described scoring system for short-term treatment response to therapeutic plasma exchange (PLEX) in a well-characterized and independent cohort of severe renal AAV presenting with RPGN. Furthermore, we compared this scoring with established classification systems in renal AAV including histopathological findings. Methods: We here directly compare the scoring system with retrospective data about PLEX treatment in our own clinical practice and according to current recommendations in a cohort of 53 patients with severe AAV presenting with RPGN confirmed by kidney biopsy. Results: We here confirm that PLEX scoring is capable to identify patients at risk for short-term poor outcome in severe AAV presenting with RPGN (p<0.0001). Furthermore, multiple stepwise regression analysis revealed that the PLEX score with renal biopsy performed best to predict poor outcome in this patient population (p<0.0001). Conclusion: Our observations underscore the relevance of performing a kidney biopsy in this patient population that is often challenged in the setting of intensive care treatment, requirement of KRT with need for anticoagulation and bleeding risk. Therefore, validation of our observations and this recent scoring system for treatment response to PLEX in independent cohorts would be of great clinical relevance in the treatment of patients with severe AAV presenting with RPGN.

Critical Role of histone deacetylase 3 in the regulation of kidney inflammation and fibrosis.

Chronic kidney disease (CKD) is characterized by kidney inflammation and fibrosis. However, the precise mechanisms leading to kidney inflammation and fibrosis are poorly understood. Since histone deacetylase is involved in inflammation and fibrosis in other tissues, we examined the role of histone deacetylase 3 (HDAC3) in the regulation of inflammation and kidney fibrosis. HDAC3 is induced in the kidneys of animal models of CKD but mice with conditional HDAC3 deletion exhibit significantly reduced fibrosis in the kidneys compared with control mice. The expression of proinflammatory and profibrotic genes was significantly increased in the fibrotic kidneys of control mice, which was impaired in mice with HDAC3 deletion. Genetic deletion or pharmacological inhibition of HDAC3 reduced the expression of proinflammatory genes in cultured monocytes/macrophages. Mechanistically, HDAC3 deacetylates Lys122 of NF-κB p65 subunit turning on transcription. RGFP966, a selective HDAC3 inhibitor, reduced fibrosis in cells and in animal models by blocking NF-κB p65 binding to κB-containing DNA sequences. Thus, our study identified HDAC3 as a critical regulator of inflammation and fibrosis of the kidney through deacetylation of NF-κB unlocking its transcriptional activity. Hence, targeting HDAC3 could serve as a novel therapeutic strategy for CKD.

Imperatorin ameliorates kidney injury in diabetic mice by regulating the TGF-ß/Smad2/3 signaling axis, epithelial-to-mesenchymal transition, and renal inflammation.

Diabetic nephropathy (DN) is a serious concern in patients with diabetes mellitus. Prolonged hyperglycemia induces oxidative damage, chronic inflammation, and build-up of extracellular matrix (ECM) components in the renal cells, leading to kidney structural and functional changes. Imperatorin (IMP) is a naturally occurring furanocoumarin derivative with proven antioxidative and anti-inflammatory properties. We investigated whether IMP could improve DN and employed high glucose (HG)-induced HK-2 cells and high-fat diet-fed streptozotocin (HFD/STZ)-generated DN experimental model in C57BL/6 mice. In vitro, IMP effectively reduced the HG-activated reactive oxygen species generation, disturbance in the mitochondrial membrane potential (MMP) and epithelial-to-mesenchymal transition (EMT)-related markers, and the transforming growth factor (TGF)-ß and collagen 1 expression in HK-2 cells. In vivo, we found an elevation of serum creatinine, kidney histology alterations, and collagen build-up in the kidneys of the DN control group. Also, we found an altered expression of EMT-related markers, upregulation of the TGF-ß/Smad2/3 axis, and elevated pro-inflammatory molecules, TNF-α, IL-1ß, IL-18 and phospho-NF-kB (p65) in the DN control group. IMP treatment did not significantly reduce the blood glucose level compared to the DN control group. However, IMP treatment effectively improved renal damage by ameliorating kidney histological changes and serum renal injury markers. IMP treatment restored renal antioxidants and exhibited anti-inflammatory effects in the kidneys. Moreover, the abnormal manifestation of EMT-related attributes and elevated levels of TGF-ß, phospho-Smad2/3, and collagen 1 were also normalized in the IMP treatment group. Our findings highlight that IMP may be a potential candidate for treating DN.

Shen Qi Wan ameliorates nephritis in chronic kidney disease via AQP1 and DEFB1 regulation.

Shen Qi Wan (SQW) has been proven to exert anti-inflammatory effects in the kidneys of CKD models accompanied by unclear therapeutic mechanisms. This study aims to evaluate the kidney-protective and anti-inflammatory effects of SQW and to elucidate its fundamental mechanisms for CKD treatment. Firstly, the main active components of SQW were identified by UPLC-Q-TOF/MS technique. Subsequently, we evaluated inflammatory factors, renal function and renal pathology changes following SQW treatment utilizing adenine-induced CKD mice and aquaporin 1 knockout (AQP1-/-) mice. Additionally, we conducted RNA-seq analysis and bioinformatics analysis to predict the SQW potential therapeutic targets and anti-nephritis pathways. Simultaneously, WGCNA analysis method and machine learning algorithms were used to perform a clinical prognostic analysis of potential biomarkers in CKD patients from the GEO database and validated through clinical samples. Lipopolysaccharide-induced HK-2 cells were further used to explore the mechanism. We found that renal collagen deposition was reduced, serum inflammatory cytokine levels decreased, and renal function was improved after SQW intervention. It can be inferred that ß-defensin 1 (DEFB1) may be a pivotal target, as confirmed by serum and renal tissue samples from CKD patients. Furthermore, SQW assuages inflammatory responses by fostering AQP1-mediated DEFB1 expression was confirmed in in vitro and in vivo studies. Significantly, the renal-protective effect of SQW is to some extent attenuated after AQP1 gene knockout. SQW could reduce inflammatory responses by modulating AQP1 and DEFB1. These findings underscore the potential of SQW as a promising contender for novel prevention and treatment strategies within the ambit of CKD management.

OTUD1 promotes hypertensive kidney fibrosis and injury by deubiquitinating CDK9 in renal epithelial cells.

Hypertensive renal disease (HRD) contributes to the progression of kidney dysfunction and ultimately leads to end-stage renal disease. Understanding the mechanisms underlying HRD is critical for the development of therapeutic strategies. Deubiquitinating enzymes (DUBs) have been recently highlighted in renal pathophysiology. In this study, we investigated the role of a DUB, OTU Domain-Containing Protein 1 (OTUD1), in HRD models. HRD was induced in wild-type or Otud1 knockout mice by chronic infusion of angiotensin II (Ang II, 1 µg/kg per min) through a micro-osmotic pump for 4 weeks. We found that OTUD1 expression levels were significantly elevated in the kidney tissues of Ang II-treated mice. Otud1 knockout significantly ameliorated Ang II-induced HRD, whereas OTUD1 overexpression exacerbated Ang II-induced kidney damage and fibrosis. Similar results were observed in TCMK-1 cells but not in SV40 MES-13 cells following Ang II (1 µM) treatment. In Ang II-challenged TCMK-1 cells, we demonstrated that OTUD1 bound to CDK9 and induced CDK9 deubiquitination: OTUD1 catalyzed K63 deubiquitination on CDK9 with its Cys320 playing a critical role, promoting CDK9 phosphorylation and activation to induce inflammatory responses and fibrosis in kidney epithelial cells. Administration of a CDK9 inhibitor NVP-2 significantly ameliorated Ang II-induced HRD in mice. This study demonstrates that OTUD1 mediates HRD by targeting CDK9 in kidney epithelial cells, suggesting OTUD1 is a potential target in treating this disease.

The effect of mycophenolate mofetil on podocytes in nephrotoxic serum nephritis.

Mycophenolate mofetil (MMF) is applied in proteinuric kidney diseases, but the exact mechanism of its effect on podocytes is still unknown. Our previous in vitro experiments suggested that MMF can ameliorate podocyte damage via restoration of the Ca2+-actin cytoskeleton axis. The goal of this study was to characterize podocyte biology during MMF treatment in nephrotoxic serum (NTS) nephritis (NTN). NTN was induced in three-week old wild-type mice. On day 3, half of the mice were treated with MMF (100 mg/kgBW/d p.o.) for one week. On day 10, we performed proteomic analysis of glomeruli as well as super-resolution imaging of the slit diaphragm. For multiphoton imaging of Ca2+ concentration ([Ca2+]i), the experimental design was repeated in mice expressing podocyte-specific Ca2+ sensor. MMF ameliorated the proteinuria and crescent formation induced by NTS. We identified significant changes in the abundance of proteins involved in Ca2+ signaling and actin cytoskeleton regulation, which was further confirmed by direct [Ca2+]i imaging in podocytes showing decreased Ca2+ levels after MMF treatment. This was associated with a tendency to restoration of podocyte foot process structure. Here, we provide evidence that MPA has a substantial direct effect on podocytes. MMF contributes to improvement of [Ca2+]i and amelioration of the disorganized actin cytoskeleton in podocytes. These data extend the knowledge of direct effects of immunosuppressants on podocytes that may contribute to a more effective treatment of proteinuric glomerulopathies with the least possible side effects.

Risk due to Elevated Uric Acid Levels in Children With Henoch-Schonlein Purpura.

PURPOSE: To compare uric acid levels in children with Henoch-Schonlein purpura (HSP)without nephritis and with renal damage, and at different pathological grades. METHODS: A total of 451 children were enrolled in this study, including 64 with HSP without nephritis and 387 HSP with kidney damage. Age, gender, uric acid, urea, creatinine and cystatin C levels were reviewed. Pathological findings of those with renal impairment were also reviewed. RESULTS: Among the HSP children with renal damage, 44 were grade I, 167 were grade II and 176 were grade III. There were significant differences in age, uric acid, urea, creatinine and cystatin C levels between the two groups (p<0.05, all). Correlation analysis showed that uric acid levels in children with HSP without nephritis were positively correlated with urea and creatinine levels (p<0.05). Uric acid levels in HSP children with renal damage was positively correlated with age, urea, creatinine and cystatin C levels (p<0.05, all). Regression analysis found that, without adding any correction factors, there were significant differences in uric acid levels between the two groups; however, after adjusting for pathological grade, there was no longer a significant difference. CONCLUSIONS: There were significant differences of uric acid levels in children with HSP without nephritis and with renal impairment. Uric acid levels in the renal impairment group were significantly higher than that in the HSP without nephritis group. Uric acid levels were related to only the presence or absence of renal damage, not to the pathological grade.

Long-term outcome of combination therapy with corticosteroids, mizoribine and RAS inhibitors as initial therapy for severe childhood IgA vasculitis with nephritis.

BACKGROUND: Patients with severe IgA vasculitis with nephritis (IgAVN) typically receive aggressive therapy as an initial approach. We have consistently performed combination therapy including corticosteroids and immunosuppressants as initial therapy for severe IgAVN over a 20-year-plus period, with only minor changes to the treatment protocol. This study seeks to reveal the efficacy of combination therapy for severe IgAVN. METHODS: We retrospectively studied 50 Japanese children diagnosed between 1996 and 2019 with clinicopathologically severe IgAVN who were defined as ISKDC classification grade IIIb-V and/or serum albumin < 2.5 g/dL. RESULTS: The median age at the onset of IgAVN was 8.0 years (IQR: 6.0-10.0). At biopsy, 44% of patients had nephrotic syndrome and 14% had kidney dysfunction. All patients were treated with combination therapy after biopsy. Abnormal proteinuria resolved after initial therapy in all 50 patients. However, eight patients (16%) had recurrence of proteinuria. Abnormal proteinuria was again resolved in three of these patients with additional treatment. At the last follow-up (median 59.5 months; IQR, 26.2-84.2), the median urine protein-to-creatine ratio was 0.08 g/gCr (IQR, 0.05-0.15), and only one patient had kidney dysfunction. CONCLUSIONS: Combination therapy provided good kidney outcomes for Japanese children with severe IgAVN. Even including recurrent cases, the degree of proteinuria was slight, and kidney function was good at the last follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

Infection-Related Cryoglobulinemic Glomerulonephritis with Serum Anti-Factor B Antibodies Identified and Staining for NAPlr/Plasmin Activity Due to Infective Endocarditis.

In this rare case of infection-related cryoglobulinemic glomerulonephritis with infective endocarditis, a 78-year-old male presented with an acute onset of fever and rapidly progressive glomerulonephritis. His blood culture results were positive for Cutibacterium modestum, and transesophageal echocardiography showed vegetation. He was diagnosed with endocarditis. His serum immunoglobulin M, IgM-cryoglobulin, and proteinase-3-anti-neutrophil cytoplasmic antibody levels were elevated, and his serum complement 3 (C3) and C4 levels were decreased. Renal biopsy results showed endocapillary proliferation, mesangial cell proliferation, and no necrotizing lesions on light microscopy, with strong positive staining for IgM, C3, and C1q in the capillary wall. Electron microscopy showed deposits in the mesangial area in the form of fibrous structures without any humps. Histological examination confirmed a diagnosis of cryoglobulinemic glomerulonephritis. Further examination showed the presence of serum anti-factor B antibodies and positive staining for nephritis-associated plasmin receptor and plasmin activity in the glomeruli, suggesting infective endocarditis-induced cryoglobulinemic glomerulonephritis.

Paeoniflorin suppresses kidney inflammation by regulating macrophage polarization via KLF4-mediated mitophagy.

BACKGROUND: Macrophages M1 polarization involved in the process of renal inflammatory injury, is a well-established hallmark of chronic kidney disease (CKD). Paeoniflorin (PF), a water-soluble monoterpene glycoside extracted from Paeonia lactiflora, revealed renal anti-inflammatory activities in our previous study. However, the potential molecular mechanism of PF on CKD remains unknown. PURPOSE: The present study aims to investigate the regulation of PF on macrophage polarization in CKD. METHODS: A CKD model was established by cationic bovine serum albumin and a murine macrophage cell line RAW264.7 induced with lipopolysaccharide (LPS) were used to clarify the underlying mechanisms of PF in CKD. RESULTS: Results showed that PF exhibited favorable protective effects on CKD model mice by promoting renal function, ameliorating renal pathological injury and podocyte damage. Furthermore, PF inhibited the infiltration of M1 macrophage marker CD68 and iNOS in kidney tissue, but increased the proportion of M2 macrophage marker CD206. In RAW264.7 cells stimulated with LPS, the levels of cytokines including IL-6, IL-1ß, TNF-α, MCP-1 were lessened under PF treatment, while the levels of Arg1, Fizz1, IL-10 and Ym-1 were augmented. These results indicated that PF promoted macrophage polarization from M1 to M2 in vivo and in vitro. More importantly, PF repaired the damaged mitochondria through increasing mitochondrial membrane potential and reducing ROS accumulation. The mitophagy-related proteins PINK1, Parkin, Bnip3, P62 and LC3 were up-regulated by PF, accompanied by the incremental expressions of Krüppel-like transcription factor 4 (KLF4). Moreover, the promotion of mitophagy and inhibition of M1 macrophage polarization owing to PF were reversed by mitophagy inhibitor Mdivi-1 or silencing KLF4. CONCLUSION: Overall, PF suppressed renal inflammation by promoting macrophage polarization from M1 to M2 and inducing mitophagy via regulating KLF4. It is expected to provide a new strategy for exploring the effects of PF in treating CKD.

Effect of Nonimmune Factors on Renal Prognosis in Adult IgA Vasculitis With Nephritis: A Long-Term Retrospective Cohort Study.

OBJECTIVE: Adult immunoglobulin A vasculitis (IgAV) is documented to be associated with more renal involvement and poorer renal outcomes compared to children, but adult IgAV nephritis (IgAV-N) data are rather limited. The present study aimed to describe the characteristics of adult IgAV-N and investigate the long-term prognostic factors. METHODS: Clinical and morphological data from 106 adult patients with biopsy-proven IgAV-N and follow-up data from 94 patients in a single Chinese center were analyzed in this retrospective study. Median follow-up time interval was 102 months. RESULTS: The median age of patients with IgAV-N at biopsy was 38 (IQR 24-53) years, and 52.8% were male. The median blood pressure was 126/80 mmHg, and 25.5% of patients were hypertensive at baseline. The median initial proteinuria was 1.4 (IQR 0.7-2.2) g/day and estimated glomerular filtration rate (eGFR) was 103 (IQR 84-121) mL/min/1.73 m2. The median time interval of onset to biopsy was 8 (IQR 3-40) weeks. In biopsy, the median percentage of global sclerosis was 5.9% (IQR 0.0-13.8), whereas 45.3% of patients had interstitial fibrosis and tubular atrophy. Further, during follow-up, 7.4% patients died, 4.3% patients progressed to endstage kidney disease (ESKD), and 6.4% patients developed > 30% eGFR reduction from baseline. Multivariate Cox proportional analyses revealed hypertension (HTN) history and > 10% global sclerosis at presentation were independent prognostic factors for poor outcome. CONCLUSION: The present adult IgAV-N cohort revealed a relatively young onset age, and lower incidence of nephrotic syndrome and ESKD. Moreover, nonimmune factors such as history of HTN and renal chronic histological lesions in biopsy played a crucial role in prognosis of IgAV-N.

Outcome of children with IgA vasculitis with nephritis treated with steroids: a matched controlled study.

BACKGROUND: IgA vasculitis (IgAV) is the most common vasculitis in children. IgAV long-term prognosis depends on kidney involvement or IgA vasculitis with nephritis (IgAVN). To date, steroid treatment (oral steroids or methylprednisolone pulses) has not proven to be formally efficient. This study aimed to assess the role of steroids on IgAVN outcome. METHODS: All children with IgAVN diagnosed 2000-2019 in 14 French pediatric nephrology units with minimal follow-up of 6 months were retrospectively included. Outcomes of patients treated with steroids were compared with those of a control group of untreated patients matched for age, sex, proteinuria, eGFR, and histological features. The primary endpoint was IgAVN remission defined as urine protein-to-creatinine ratio < 20 mg/mmol without impaired eGFR one year after disease onset. RESULTS: A total of 359 patients with IgAVN were included with a median follow-up time of 249 days (range 43-809). One hundred eight (30%) patients received oral steroids alone, 207 (51%) patients received three methylprednisolone pulses followed by oral steroids, and 44 patients (12.5%) did not receive steroids. Thirty-two children treated with oral steroids alone were compared with 32 matched control patients who did not receive steroids. One year after disease onset, IgAVN remission proportion was not different between these two groups: 62% versus 68%, respectively. Ninety-three children treated with oral steroids alone were compared with 93 matched patients treated with three methylprednisolone pulses followed by oral corticosteroids. IgAVN remission proportion was not different between these two groups: 77% versus 73%, respectively. CONCLUSION: The benefit of oral steroids alone and methylprednisolone pulses could not be established based on this observational study. Randomized controlled trials are thus required to determine the efficacy of steroids in IgAVN. A higher resolution version of the Graphical abstract is available as Supplementary information.

Stem Cells in Kidney Ischemia: From Inflammation and Fibrosis to Renal Tissue Regeneration.

Ischemic nephropathy consists of progressive renal function loss due to renal hypoxia, inflammation, microvascular rarefaction, and fibrosis. We provide a literature review focused on kidney hypoperfusion-dependent inflammation and its influence on renal tissue's ability to self-regenerate. Moreover, an overview of the advances in regenerative therapy with mesenchymal stem cell (MSC) infusion is provided. Based on our search, we can point out the following conclusions: 1. endovascular reperfusion is the gold-standard therapy for RAS, but its success mostly depends on treatment timeliness and a preserved downstream vascular bed; 2. anti-RAAS drugs, SGLT2 inhibitors, and/or anti-endothelin agents are especially recommended for patients with renal ischemia who are not eligible for endovascular reperfusion for slowing renal damage progression; 3. TGF-ß, MCP-1, VEGF, and NGAL assays, along with BOLD MRI, should be extended in clinical practice and applied to a pre- and post-revascularization protocols; 4. MSC infusion appears effective in renal regeneration and could represent a revolutionary treatment for patients with fibrotic evolution of renal ischemia.

Two Cases of Acute Focal Bacterial Nephritis With Central Nervous System Manifestations in Children and Literature Review.

Acute focal bacterial nephritis (AFBN) is a kidney disease characterized by a localized bacterial infection that manifests as an inflammatory mass. Most children with AFBN have nonspecific symptoms including fever, vomiting, and abdominal discomfort, and some develop neurological symptoms such as meningeal irritation, unconsciousness, and seizures as their condition worsens. This was 2 cases of AFBN with central nervous system manifestations in children, and we analyzed its possible mechanisms of the clinical and radiographic features. We experience 2 very unusual cases of AFBN which were linked to central nervous system abnormalities. A 6-year-old boy with AFBN and clinically moderate ncephalitis/encephalopathy with a reversible splenial lesion (MERS) presented with neurological symptoms, including unconsciousness and convulsions. The second case involved an 8-year-old child with AFBN-associated acute encephalopathy who exhibited neurological symptoms, including unconsciousness. According to previous research, AFBN is linked to central nervous system impairment. As a result, when a clinician meets a patient with an inexplicable fever caused by a neurological condition, he should pay attention to this diagnosis of AFBN and follow it in the abdominal graph.