An Elderly Case of Minimal Change Nephrotic Syndrome: Correlation between Renal Tubular Dysfunction and the Onset of Oliguric Acute Kidney Injury Requiring Hemodialysis.

Several theories have been proposed to explain the development of severe acute kidney injury (AKI) in patients with minimal change nephrotic syndrome (MCNS), but the exact mechanism remains unclear. We encountered an elderly patient with biopsy-proven MCNS who suffered from oliguric AKI, which required hemodialysis at the onset and during the first relapse of nephrotic syndrome. Throughout her relapse, we were able to monitor tubular injury markers, namely, urinary N-acetyl-ß-D-glucosaminidase and urinary alpha-1-microglobulin levels. This patient had hypertension. 8.5 years after achieving complete remission, she experienced a relapse of nephrotic syndrome accompanied by AKI, necessitating hemodialysis. The hemodialysis was discontinued after 7 weeks of corticosteroid therapy and cyclosporin A treatment. During this relapse, we observed a correlation between the sudden increase in renal tubular injury markers and proteinuria levels and the progression of severe AKI. Conversely, a reduction in renal tubular injury markers and proteinuria was associated with the resolution of AKI. The abrupt elevation of both tubular injury markers and proteinuria levels suggests a possible breakdown in protein endocytosis in proximal tubular cells. Moreover, it is less likely that the acute reduction in intra-glomerular pressure is the primary cause of tubular injury, as it might result in a decrease in both glomerular filtration rate and proteinuria levels. It is conceivable that massive proteinuria, in conjunction with the patient's clinical characteristics, may contribute to tubular injury, ultimately leading to severe AKI in this patient.

Effective Management of Hypertensive Emergencies with Aliskiren Treatment in a Patient Before and After Introducing Hemodialysis Secondary to Scleroderma Renal Crisis-like Condition Under Corticosteroid Treatment for Sjögren Syndrome-associated Multiple Mononeuropathy.

A middle-aged woman presented with hypertensive emergency after corticosteroid treatment for Sjögren syndrome-associated multiple mononeuropathy with suspected systemic sclerosis. Hypertensive heart failure with hyperreninemia improved with antihypertensives, including aliskiren; however, she became hemodialysis-dependent. Clinical findings and biopsy-proven thrombotic microangiopathy indicated conditions resembling scleroderma renal crisis (SRC). Severe hypertension and heart failure with hyperreninemia occurred after stopping aliskiren for hypotension due to diverticular bleeding, which improved after the reintroduction of aliskiren. Aliskiren appears to be effective in managing hypertensive heart failure in patients with SRC. Nevertheless, hemodialysis remained necessary in our case, and whether or not aliskiren can restore the renal function is unclear.

Discontinuing Hemodialysis through Corticosteroid Treatment in a Patient with Cryofibrinogen-associated Glomerulonephritis.

Cryofibrinogen-associated glomerulonephritis (CryoFiGN) is rare, and its diagnosis is difficult while treatment is not established. We herein report an elderly woman with CryoFiGN who experienced recurrent purpura and nephritic features that subsequently progressed to nephrotic syndrome and required hemodialysis during the 18-month clinical course. The patient was treated with corticosteroids, which led to the discontinuation of hemodialysis. The diagnosis of CryoFiGN was based on the clinical presentation, characteristic glomerular deposits, and results of laser microdissection and liquid chromatography-tandem mass spectrometry of the glomeruli. This case highlights the potential utility of corticosteroids as a treatment option for patients with CryoFiGN, even after hemodialysis.

Slowly Progressive ANCA-associated Glomerulonephritis with Strong Mesangial MPO Deposits Following a Diagnosis of Interstitial Lung Disease: A Case Report.

An elderly woman showed positive conversion of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCAs) following the diagnosis of interstitial lung disease (ILD) and glomerular hematuria and subsequently experienced slowly progressive glomerulonephritis. A kidney biopsy revealed chronic damage and necrotizing crescentic glomerulonephritis with mesangial MPO deposits. After corticosteroid treatment, the patient's urinalysis results and MPO-ANCA titers almost normalized and her renal function stabilized. This case is similar to recently reported cases of slowly progressive ANCA-associated glomerulonephritis. ILD likely triggered the production of MPO-ANCAs, and the accumulation of MPO deposits in the glomeruli may have contributed to the progression of her renal disease.

A Diagnostic and Therapeutic Dilemma Concerning Exostosin 1/Exostosin 2-associated Lupus-like Membranous Nephropathy with Positive Antinuclear Antibody in an Elderly Man with Various Immune Abnormalities.

Exostosin 1 (EXT1) and exostosin 2 (EXT2)-associated membranous nephropathy (MN) may be associated with active autoimmune disease. We encountered an elderly man who presented with EXT1/EXT2-associated lupus-like MN with full house immune deposits, monoclonal gammopathy of uncertain significance and Sjögren's syndrome. The patient exhibited various other immune abnormalities. Although he did not fulfill the criteria of clinical systemic lupus erythematosus (SLE), he met a stand-alone renal criterion of the Systemic Lupus International Collaborating Clinics (SLICC) 2012. Whether or not a stand-alone renal criterion with EXT1/EXT2 positivity, as in the present patient, can efficiently guide decisions regarding the diagnosis and treatment of SLE remains a clinical dilemma.

Nicorandil protects podocytes via modulation of antioxidative capacity in acute puromycin aminonucleoside-induced nephrosis in rats.

Nephrotic syndrome, characterized by proteinuria and hypoalbuminemia, results from the dysregulation of glomerular podocytes and is a significant cause of end-stage kidney disease. Patients with idiopathic nephrotic syndrome are generally treated with immunosuppressive agents; however, these agents produce various adverse effects. Previously, we reported the renoprotective effects of a stimulator of the mitochondrial ATP-dependent K+ channel (MitKATP), nicorandil, in a remnant kidney model. Nonetheless, the cellular targets of these effects remain unknown. Here, we examined the effect of nicorandil on puromycin aminonucleoside-induced nephrosis (PAN) rats, a well-established model of podocyte injury and human nephrotic syndrome. PAN was induced using a single intraperitoneal injection. Nicorandil was administered orally at 30 mg/kg/day. We found that proteinuria and hypoalbuminemia in PAN rats were significantly ameliorated following nicorandil treatment. Immunostaining and ultrastructural analysis under electron microscopy demonstrated that podocyte injury in PAN rats showed a significant partial attenuation following nicorandil treatment. Nicorandil ameliorated the increase in the oxidative stress markers nitrotyrosine and 8-hydroxy-2-deoxyguanosine in glomeruli. Conversely, nicorandil prevented the decrease in levels of the antioxidant enzyme manganese superoxide dismutase in PAN rats. We found that mitochondrial Ca2+ uniporter levels in glomeruli were higher in PAN rats than in control rats, and this increase was significantly attenuated by nicorandil. We conclude that stimulation of MitKATP by nicorandil reduces proteinuria by attenuating podocyte injury in PAN nephrosis, which restores mitochondrial antioxidative capacity, possibly through mitochondrial Ca2+ uniporter modulation. These data indicate that MitKATP may represent a novel target for podocyte injury and nephrotic syndrome.NEW & NOTEWORTHY Our findings suggest that the mitochondrial Ca2+ uniporter may be an upstream regulator of manganese superoxide dismutase and indicate a biochemical basis for the interaction between the ATP-sensitive K+ channel and Ca2+ signaling. We believe that our study makes a significant contribution to the literature because our results indicate that the ATP-sensitive K+ channel may be a potential therapeutic target for podocyte injury and nephrotic syndrome.

IgA vasculitis with transient glomerular hematuria, diarrhea, and pericarditis following COVID-19 mRNA vaccination in a young patient with possible pre-existing ulcerative colitis.

Exacerbations or de novo autoimmune/autoinflammatory disease have been reported after COVID-19 vaccination. A young male presented with cutaneous IgA vasculitis with glomerular hematuria, diarrhea and pericarditis following his second COVID-19 mRNA vaccination. He also showed positivity for proteinase 3 anti-neutrophil cytoplasmic antibody (PR3-ANCA) and anti-cardiolipin antibody. Skin biopsy was compatible to IgA vasculitis. His purpura subsided and hematuria spontaneously disappeared. Treatment with anti-inflammatory medications and prednisolone resolved the pericarditis. He had a history of persistent diarrhea, and colonic biopsies showed possible ulcerative colitis without vasculitis. Kidney biopsy after prednisolone therapy revealed minor glomerular abnormalities without any immune reactants and did not show vasculitis. After prednisolone treatment, PR3-ANCA decreased in a medium degree despite of improvement of symptoms and inflammatory data, suggesting that his PR3-ANCA may be associated with ulcerative colitis. The cause of the transient glomerular hematuria was unclear, however, it might be caused by focal glomerular active lesions (glomerular vasculitis) due to vaccine-induced IgA vasculitis with nephritis. This case highlights that COVID-19 mRNA vaccination can activate multiple autoimmune/autoinflammatory systems. The conditions might help us better understand the mutual mechanisms of the relevant disorders.

Tubulointerstitial B-cell infiltration and tertiary lymphoid tissue in adult-onset immunoglobulin A vasculitis with nephritis.

PURPOSE: This study aimed to examine tubulointerstitial B-cell infiltration in patients with adult-onset immunoglobulin A vasculitis (IgAV) and nephritis (IgAV-N), and to evaluate whether B-cell infiltration correlated with clinicopathological variables at kidney biopsy and with short-term renal outcomes. METHODS: Twenty patients with adult-onset IgAV-N and 10 control patients with thin basement membrane nephropathy (TBMN) were retrospectively examined. The lymphatic organization was graded based on B-cell infiltration and was classified into 4 groups: 0-T cells without B cells, 1-scattered B and T cells, 2-clustered B and T cells, and 3-nodular compartmentally arranged B- and T-cell aggregates, equivalent to tertiary lymphoid tissue (TLT). RESULTS: The B-cell infiltration grade was significantly higher in patients with IgAV-N than in patients with TBMN, and no age differences were observed. The B-cell infiltration grade in patients with IgAV-N was significantly correlated with age, serum IgA level, renal dysfunction, and tubulointerstitial injury parameters, but was not correlated with duration after purpura or glomerular injury parameters. Most patients with IgAV-N were treated with corticosteroids. The proteinuria level was significantly decreased, but renal function was not improved in 12 patients after the 24-month follow-up compared with the values at baseline. The B-cell infiltration grade was significantly correlated with renal dysfunction after 24 months of follow-up. CONCLUSIONS: The B-cell infiltration grade in patients with IgAV-N was associated with renal dysfunction and tubulointerstitial injuries but not with glomerular injury parameters. B-cell infiltration and TLT might have a pathologically significant role in irreversible renal dysfunction in patients with early phase adult-onset IgAV-N.

Selenium Associates With Response to Erythropoiesis-Stimulating Agents in Hemodialysis Patients.

Introduction: Impaired response to erythropoiesis-stimulating agents (ESAs) is associated with increased mortality in patients with end-stage kidney disease. However, the underlying mechanisms are not fully elucidated. Accumulating data reveal that selenium (Se), a trace element, plays a key role in stress erythropoiesis and erythrocyte homeostasis. We evaluated the relationship between serum Se levels and the response to ESAs in hemodialysis patients. Methods: In this cross-sectional study, we determined serum Se levels in 173 hemodialysis patients. We analyzed the association of serum Se with ESA responsiveness, as defined by ESA resistance index. Results: Of the study participants, 50% had lower Se levels than the population-based reference values. We found that serum Se levels were significantly and inversely correlated with erythropoiesis resistance index (ERI) but not transferrin saturation (TSAT) or ferritin levels. Multiple regression analyses confirmed the association between Se levels and ESA hyporesponsiveness, independently of other known factors, such as iron status, being female, and dialysis vintage (ß = -0.11, P < 0.001). When patients were divided according to Se levels and iron status, both low serum Se (<10.5 µg/dl) and iron deficiency significantly affected the response to ESA. Conversely, serum Se levels were significantly different among groups when patients were divided according to ERI quartiles. The association of low serum Se with ESA hyporesponsiveness persisted after adjustment of confounding variables. Conclusion: Serum Se levels are associated with the response to ESAs and can predict ESA resistance independently of iron status in Japanese hemodialysis patients. These data open the possibility to test whether Se supplementation reduces ESA demand.

A Patient with Acute Kidney Injury Associated with Massive Proteinuria and Acute Hyperuricemia after Epileptic Seizures.

A 25-year-old man presented with acute kidney injury (AKI), massive proteinuria and hyperuricemia after epileptic seizures. His AKI improved along with the disappearance of proteinuria after corticosteroid treatment. A kidney biopsy revealed no significant glomerular abnormalities, but varying degrees of tubular injury, such as proximal tubular simplification, mild distal tubular proliferation, and Tamm-Horsfall protein-like material accumulation with extravasation into the interstitium, were noted. A further analysis revealed the intratubular depositions of uric acid crystals, indicating the involvement of acute uric acid nephropathy associated with seizures. Our patient's condition is rare, and the clinicopathological aspects of the diagnostic challenges are discussed.

Emergence of proteinase 3-antineutrophil cytoplasmic antibody-associated glomerulonephritis with mesangial immune deposition during the clinical course of IgG λ monoclonal gammopathy of uncertain significance.

Patients with monoclonal gammopathy of uncertain significance (MGUS) is sometimes associated with renal diseases, usually due to the deposition of secreted monoclonal immunoglobulin or a fragment thereof, a condition which is defined as monoclonal gammopathy of renal significance. Patients with MGUS appear to be at increased risk for various autoimmune conditions. We report the case of a 68-year-old man developed nephritic syndrome and mild renal insufficiency during the course of IgG λ MGUS. Laboratory findings showed hypocomplementemia, cryoglobulinemia, proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) positivity and monoclonal proteins (λ light chain and λ-Bence-Jones protein) in the urine. A kidney biopsy revealed crescentic glomerulonephritis with mesangial immune deposits without paraproteins. Treatment with prednisolone for ANCA-associated glomerulonephritis, normalized urinalysis and decreased PR3-ANCA but MGUS persisted. This is a rare case of PR3-ANCA-associated glomerulonephritis with comorbid IgG λ MGUS with various pathological paraproteins. We highlight it as a clinical example with diagnostic and therapeutic implications.

A Young Patient with Microscopic Polyangiitis Requiring Hemodialysis with Complications of Repeated Episodes of Posterior Reversible Encephalopathy Syndrome Probably Due to Different Etiologies.

A young woman with microscopic polyangiitis (MPA) requiring hemodialysis showed repeated posterior reversible encephalopathy syndrome (PRES) with spatiotemporal multiple lesions over a period of two months. The first PRES episode with confusion and the second PRES episode with vertigo and nausea were caused by MPA, hypertension and renal failure. These symptoms were improved by the reinforcement of MPA treatment and blood pressure management. The third PRES episode with nausea, headache, seizure and visual changes was induced by rituximab infusion and hypertension. The PRES was improved with blood pressure and convulsant management. These conditions are challenging to diagnose and treat.

Bilateral nephromegaly due to direct leukemic cell invasion in the initial and relapse phases of T-cell acute lymphoblastic leukaemia: A case report.

RATIONALE: T-cell acute lymphoblastic leukemia is a relatively uncommon disorder in adults. Kidneys are not frequently invaded by leukemic cells, and patients with adult ALL showing nephromegaly as an initial presentation are rare. PATIENT CONCERNS: A 54-year-old man was referred to our institution for mild anemia and thrombocytopenia. Laboratory tests showed bicytopenia with abnormal lymphoid cells in the peripheral blood and mild renal dysfunction. DIAGNOSIS: Ultrasonography and computed tomography (CT) revealed bilateral enlargement of the kidneys. [18F]-fluorodeoxyglucose positron emission tomography/CT demonstrated a strong increase in metabolic uptake in the bilateral kidneys. A kidney biopsy revealed a leukemia invasion into the parenchyma. Based on the lymphocytic repertoire, the patient's condition was diagnosed as T-cell acute lymphoblastic leukaemia. INTERVENTIONS: The patient received hyper-cyclophosphamide, vincristine, adriamycin, and dexamethasone and high-dose methotrexate and cytarabine as induction chemotherapy. After his leukemia relapsed, he received nelarabine as a second induction therapy and underwent haploidentical peripheral blood stem cell transplantation. OUTCOMES: Complete remission (CR) was achieved after chemotherapy. Chemotherapy also improved renal function associated with the normalization of bilateral nephromegaly. Repeated [18F]-fluorodeoxyglucose - positron emission tomography/CT posttreatment showedregression of metabolic uptake in the bilateral kidneys. The patient underwent cord blood transplantation at the first CR, but his leukemia relapsed 9 months later. At relapse, bilateral nephromegaly reappeared. Then, the second induction therapy induced CR for at least 10 months after induction therapy. LESSONS: Although rare, ALL in the initial and relapsed phases can be associated with bilateral nephromegaly and renal impairment due to the invasion of leukemic cells into the parenchyma with or without abnormal leukemic cells in circulation. Leukemia is an important differential diagnosis of renal impairment with bilateral nephromegaly.

Characterization of pendrin in urinary extracellular vesicles in a rat model of aldosterone excess and in human primary aldosteronism.

Pendrin is a Cl-/HCO3- exchanger selectively present in the intercalated cells of the kidney. Although experimental studies have demonstrated that pendrin regulates blood pressure downstream of the renin-angiotensin-aldosterone system, its role in human hypertension remains unclear. Here, we analyzed the quantitative changes in pendrin in urinary extracellular vesicles (uEVs) isolated from a total of 30 patients with primary aldosteronism (PA) and from a rat model of aldosterone excess. Western blot analysis revealed that pendrin is present in dimeric and monomeric forms in uEVs in humans and rats. In a rodent model that received continuous infusion of aldosterone with or without concomitant administration of the selective mineralocorticoid receptor (MR) antagonist esaxerenone, pendrin levels in uEVs, as well as those of epithelial Na+ channel (ENaC) and Na-Cl-cotransporter (NCC), were highly correlated with renal abundance. In patients with PA, pendrin levels in uEVs were reduced by 49% from baseline by adrenalectomy or pharmacological MR blockade. Correlation analysis revealed that the magnitude of pendrin reduction after treatment significantly correlated with the baseline aldosterone-renin ratio (ARR). Finally, a cross-sectional analysis of patients with PA confirmed a significant correlation between the ARR and pendrin levels in uEVs. These data are consistent with experimental studies showing the role of pendrin in aldosterone excess and suggest that pendrin abundance is attenuated by therapeutic interventions in human PA. Our study also indicates that pendrin analysis in uEVs, along with other proteins, can be useful to understand the pathophysiology of hypertensive disorders.

Renal Involvement as Rare Acute Tubulointerstitial Nephritis in a Patient with Eosinophilic Disorder Treated with Early Add-on Administration of Mepolizumab.

A 39-year-old man presented with peripheral eosinophilia, pulmonary eosinophilic infiltrate, and renal failure due to acute tubulointerstitial nephritis (TIN). He had experienced childhood asthma and was negative for anti-neutrophil cytoplasmic antibody (ANCA). He was tentatively diagnosed with ANCA-negative eosinophilic granulomatous polyangiitis (EGPA) or idiopathic hypereosinophilic syndrome (HES). Renal involvement of isolated TIN with eosinophil infiltration is rare in EGPA and HES and does not seem to have a good prognosis in the literature. However, his condition improved well with corticosteroids and mepolizumab. The revised classification of EGPA based on the etiology should dictate the proper treatment in suspected EGPA patients with nonsystemic vasculitis.

A Ruptured Jejunal Arterial Aneurysm in a Young Woman Undergoing Chronic Hemodialysis Due to Myeloperoxidase-antineutrophil Cytoplasmic Antibody-associated Vasculitis.

A 21-year-old woman was admitted to our hospital because of massive intestinal bleeding. She started hemodialysis due to myeloperoxidase antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) at 18 years of age. Her ANCA titers remained stable; however, her C-reactive protein increased on 5 mg/day prednisolone before admission. Computed tomography angiography revealed a ruptured jejunal arterial aneurysm. Transcatheter arterial embolization, blood transfusion and the reinforcement of steroid therapy resolved her symptoms of AAV. Our case of a young patient with AAV and medium-sized arterial vasculitis is rare and emphasizes that the ANCA titer does not always rise, especially in patients with nonrenal vasculitis flare-ups.

Pyuria without Casts and Bilateral Kidney Enlargement Are Probable Hallmarks of Severe Acute Kidney Injury Induced by Acute Pyelonephritis: A Case Report and Literature Review.

The patient was a 38-year-old man who had experienced nausea and fever for a few days and presented with back pain, oliguria, and pyuria, suggesting acute pyelonephritis (APN). He showed acute kidney injury (AKI) with bilateral kidney enlargement and was using nonsteroidal anti-inflammatory drugs (NSAIDs). AKI-induced by APN was confirmed by kidney biopsy. The AKI was successfully treated with antibiotic therapy. A search of the relevant literature for reports on histopathologically-proven APN-induced severe AKI revealed that the key characteristics were bilateral kidney enlargement with pyuria without casts. Oligoanuria was frequently associated with APN-induced severe AKI, and NSAID use may be a possible risk factor. Prompt antibiotic treatment based on the clinical characteristics of APN-induced AKI can improve the renal outcome.

Urinary phosphate-containing nanoparticle contributes to inflammation and kidney injury in a salt-sensitive hypertension rat model.

Although disturbed phosphate metabolism frequently accompanies chronic kidney disease (CKD), its causal role in CKD progression remains unclear. It is also not fully understood how excess salt induces organ damage. We here show that urinary phosphate-containing nanoparticles promote kidney injury in salt-sensitive hypertension. In Dahl salt-sensitive rats, salt loading resulted in a significant increase in urinary phosphate excretion without altering serum phosphate levels. An intestinal phosphate binder sucroferric oxyhydroxide attenuated renal inflammation and proteinuria in this model, along with the suppression of phosphaturia. Using cultured proximal tubule cells, we confirmed direct pathogenic roles of phosphate-containing nanoparticles in renal tubules. Finally, transcriptome analysis revealed a potential role of complement C1q in renal inflammation associated with altered phosphate metabolism. These data demonstrate that increased phosphate excretion promotes renal inflammation in salt-sensitive hypertension and suggest a role of disturbed phosphate metabolism in the pathophysiology of hypertensive kidney disease and high salt-induced kidney injury.

Cardio-renal protective effect of the xanthine oxidase inhibitor febuxostat in the 5/6 nephrectomy model with hyperuricemia.

Although hyperuricemia has been shown to be associated with the progression of cardiovascular disorder and chronic kidney disease (CKD), there is conflicting evidence as to whether xanthine oxidase (XO) inhibitors confer organ protection besides lowering serum urate levels. In this study, we addressed the cardio-renal effects of XO inhibition in rodent CKD model with hyperuricemia. Sprague-Dawley rats underwent 5/6 nephrectomy and received a uricase inhibitor oxonic acid for 8 weeks (RK + HUA rats). In some rats, a XO inhibitor febuxostat was administered orally. Compared with control group, RK + HUA group showed a significant increase in albuminuria and renal injury. Febuxostat reduced serum uric acid as well as urinary albumin levels. Histological and immunohistochemical analysis of the kidney revealed that febuxostat alleviated glomerular, tubulointerstitial, and arteriolar injury in RK + HUA rats. Moreover, in the heart, RK + HUA showed individual myofiber hypertrophy and cardiac fibrosis, which was significantly attenuated by febuxostat. We found that renal injury and the indices of cardiac changes were well correlated, confirming the cardio-renal interaction in this model. Finally, NF-E2-related factor 2 (Nrf2) and the downstream target heme oxygenase-1 (HO-1) protein levels were increased both in the heart and in the kidney in RK + HUA rats, and these changes were alleviated by febuxostat, suggesting that tissue oxidative stress burden was attenuated by the treatment. These data demonstrate that febuxostat protects against cardiac and renal injury in RK + HUA rats, and underscore the pathological importance of XO in the cardio-renal interaction.