Renin Inhibition and the Long-Term Renal Function in Patients With Hypertensive Emergency: A Retrospective Cohort Study

BACKGROUND

The rehospitalization rate in a hypertensive emergency is high, indicating the necessity for optimizing its long-term management. The role of the renin-angiotensin system (RAS) blockade in this disorder remains uncertain.

METHODS

We conducted a retrospective analysis involving 20 admitted patients who received aliskiren, a direct renin inhibitor (DRI), for the management of hypertensive emergency associated with elevated plasma renin activity (PRA). We analyzed the changes in blood pressure (BP), kidney function, and RAS activity in the subacute and chronic phases.

RESULTS

The use of DRI was associated with a marked reduction in PRA (median, from 25.0 to 1.2 ng/ml/h) and serum aldosterone levels (from 404 to 130 pg/ml) during the index admission. BP also decreased from 226/143 to 142/80 mm Hg. A comparison of clinical characteristics according to the renal function indicated that dialysis-dependent patients had higher aldosterone levels than non-dialysis-dependent patients at admission, despite comparable BP levels. After a median follow-up of 567 days in non-dialysis-dependent patients with DRI, eGFR levels were significantly increased from 14.3 to 23.1 ml/min/1.73 m2. PRA levels were consistently suppressed at 0.8 ng/ml/h. We found a significant correlation between the degree of PRA suppression and changes in eGFR (r = -0.58), indicating that the effective blockade of RAS is associated with the preservation of eGFR in the study subjects.

CONCLUSIONS

DRI can successfully suppress PRA in patients with high-renin hypertensive emergency in both subacute and chronic phases. An efficient RAS blockade is associated with preserved renal function in these patients.

Slowly Progressive ANCA-associated Glomerulonephritis with Strong Mesangial MPO Deposits Following a Diagnosis of Interstitial Lung Disease

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.

Evidence of a Hardening in the Cosmic Ray Proton Spectrum at around 166 TeV Observed by the GRAPES-3 Experiment

We present the measurement of the cosmic ray proton spectrum from 50 TeV to 1.3 PeV using 7.81×10^{6} extensive air shower events recorded by the ground-based GRAPES-3 experiment between 1 January 2014 and 26 October 2015 with a live time of 460 day. Our measurements provide an overlap with direct observations by satellite and balloon-based experiments. The electromagnetic and muon components in the shower were measured by a dense array of plastic scintillator detectors and a tracking muon telescope, respectively. The relative composition of the proton primary from the air shower data containing all primary particles was extracted using the multiplicity distribution of muons which is a sensitive observable for mass composition. The observed proton spectrum suggests a spectral hardening at ∼166  TeV and disfavors a single power law description of the spectrum up to the Knee energy (∼3  PeV).

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.

[A Case of Double Cancer of Squamous Cell Carcinoma of the Rectum and Adenocarcinoma of the Sigmoid Colon]

A 72-year-old male was transported to our hospital with complaints of heart palpitations and dyspnea since a month earlier and was immobile. Blood examination showed severe anemia, and colonoscopy revealed circumferential tumors in the rectum and the sigmoid colon. Histopathologic examination revealed the tumors as squamous cell carcinoma of the rectum and adenocarcinoma of the sigmoid colon. Therefore, they were diagnosed as double colorectal cancers. CT and MRI showed that rectal cancer invaded the seminal vesicles and the prostate; therefore, the patient underwent neoadjuvant chemoradiotherapy(oral capecitabine and concomitant radiation therapy: a total dose of 50.4 Gy/28 Fr)followed by total pelvic exenteration. Subsequent specimen pathology revealed a tumor regression grading of Grade 2 for the rectal and sigmoid colon cancers, and both were staged as ypT3N0M0, ypStage Ⅱa. Herein, we report a rare case of double cancer of adenocarcinoma of the sigmoid colon and squamous cell carcinoma of the rectum with a literature review.

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.

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.

Self-measured home blood pressure highlights cardiovascular risk in women: the HOMED-BP study

No studies examined sex differences in relation to the prognostic significance of self-measured home blood pressure (HBP). We compared the predictive power for the risk of cardiovascular events in 1547 women and 1516 men with hypertension using HBP captured at treatment-free baseline and during on-treatment follow-up, based on the Hypertension Objective Treatment Based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) study. To express the change in risk for the composite cardiovascular endpoint associated with a 1-SD increase in HBP at baseline or on treatment, we derived multivariable-adjusted hazard ratios (HR) based on a Cox regression model. Over a median follow-up of 7.3 years, 100 composite events occurred, including 40 events in women. In women, systolic HBP both at baseline and on-treatment showed significant risk increment (at baseline: HR per 1-SD increment, 1.62; 95% confidence interval [CI], 1.17-2.24. on-treatment: HR, 1.74; 95% CI, 1.32-2.29). However, systolic HBP at baseline did not predict cardiovascular events in men (P = 0.25). On-treatment HBP was significantly associated with cardiovascular risk (P ≤ 0.012) irrespective of sex. Nevertheless, the point estimate of HR for systolic HBP in men (1.33) was less than that in women (1.74), and the interaction of sex with 1 SD-increase in systolic HBP in cardiovascular risk was significant irrespective of baseline (P = 0.039) or follow-up (P = 0.040) measurement when they were mutually adjusted. The increase in cardiovascular risk with the systolic HBP was steeper in women than in men for both baseline and on-treatment. The current findings unveil the importance of the control of systolic HBP, especially in women. Clinical Trial Registration: UMIN Clinical Trial Registry ( http://www.umin.ac.jp/ctr ), Unique identifier: C000000137.

[Impact of Residual Radioactivity Rate of 99mTc-macro Aggregated Albumin (MAA) in Syringes and Administration Routes with a Focus on Pediatric Nuclear Medicine Examinations]

PURPOSE

The purpose of this study was to evaluate the residual radioactivity in the syringe and route of administration of a low fluid volume 99mTc-macro aggregated albumin (MAA) intended for pediatric nuclear medicine examinations.

METHOD

We evaluated the residual characteristics, as the effect of elapsed time from drawing up of radiopharmaceuticals to plastic syringe to administration, and the effect of volume of 99mTcO4- solution to be labeled, the effect of rinsed times of plastic syringe, effect of dose of calculated by consensus guidelines for pediatric nuclear medicine and residual location in injection sets with 99mTc-MAA. Residual radioactivity was measured using planar images obtained by the gamma camera.

RESULTS

Residual radioactivity rate of 99mTc-MAA, 99mTc-MAG3, 123I-IMP showed 41.3±1.6%, 14.4±0.6%, 14.6±2.0%, respectively. 99mTc-MAA clearly showed a higher residual rate. Residual radioactivity rate increased with the extension of the elapsed time, and reached a high value of 41.3% in 30 minutes. Residual radioactivity rate was dependent on the different volume of 99mTcO4- to be labeled (4.0 ml and 8.0 ml). Residual radioactivity rate did not change when the number of rinsed was more than one. Residual rate was around 40% at all doses of calculated by consensus guidelines for pediatric nuclear medicine.

CONCLUSION

99mTc-MAA showed the highest residual radioactivity rate among radiopharmaceuticals used in pediatric nuclear medicine examinations. The factor that most affected the residual radioactivity rate of 99mTc-MAA was the elapsed time from draw up to the plastic syringe to administration.

Strangulated bowel obstruction caused by an ileo-ileal knot: a rare case report

BACKGROUND

Intestinal knot formation is a condition wherein two segments of the intestine are knotted together; however, reports of small-intestinal ileo-ileal knot formation are rare.

CASE PRESENTATION

The patient was a 62-year-old Asian male with a history of endoscopic colorectal adenoma resection and a spontaneous pneumothorax. The patient had no history of a laparotomy. He consulted his local doctor with the chief complaint of abdominal pain and was admitted to our hospital with suspicion of an acute abdomen. The abdomen had muscular guarding with tenderness and rebound tenderness. Contrast-enhanced computed tomography (CT) showed torsion of the mesentery of the small intestine with poor contrast filling. The patient was referred to our department with strangulated bowel obstruction and underwent an emergency laparotomy. Intraoperative findings revealed that two segments of the ileum were wrapped around each other to form a knot, and the strangulated small bowel was necrotic. After the release of the knot, partial resection of the small intestine was performed from 220 cm distal to the ligament of Treitz to 80 cm proximal to the cecum. The patient had a good postoperative course and was discharged on the 11th postoperative day.

CONCLUSION

Ileo-ileal knots should be considered as part of the differential diagnosis when treating strangulated bowel obstruction.

Mineralocorticoid Receptor Antagonists for Preventing Chronic Kidney Disease Progression: Current Evidence and Future Challenges

Regulation and action of the mineralocorticoid receptor (MR) have been the focus of intensive research over the past 80 years. Genetic and physiological/biochemical analysis revealed how MR and the steroid hormone aldosterone integrate the responses of distinct tubular cells in the face of environmental perturbations and how their dysregulation compromises fluid homeostasis. In addition to these roles, the accumulation of data also provided unequivocal evidence that MR is involved in the pathophysiology of kidney diseases. Experimental studies delineated the diverse pathological consequences of MR overactivity and uncovered the multiple mechanisms that result in enhanced MR signaling. In parallel, clinical studies consistently demonstrated that MR blockade reduces albuminuria in patients with chronic kidney disease. Moreover, recent large-scale clinical studies using finerenone have provided evidence that the non-steroidal MR antagonist can retard the kidney disease progression in diabetic patients. In this article, we review experimental data demonstrating the critical importance of MR in mediating renal injury as well as clinical studies providing evidence on the renoprotective effects of MR blockade. We also discuss areas of future investigation, which include the benefit of non-steroidal MR antagonists in non-diabetic kidney disease patients, the identification of surrogate markers for MR signaling in the kidney, and the search for key downstream mediators whereby MR blockade confers renoprotection. Insights into these questions would help maximize the benefit of MR blockade in subjects with kidney diseases.

Long COVID and hypertension-related disorders: a report from the Japanese Society of Hypertension Project Team on COVID-19

The coronavirus disease 2019 (COVID-19) affects infected patients even after the acute phase and impairs their health and quality of life by causing a wide variety of symptoms, referred to as long COVID. Although the evidence is still insufficient, hypertension is suspected to be a potential risk factor for long COVID, and the occurrence of cardiovascular diseases seems to be a key facet of multiple conditions observed in long COVID. Nonetheless, there are few reports that comprehensively review the impacts of long COVID on hypertension and related disorders. As a sequel to our previous report in 2020 which reviewed the association of COVID-19 and hypertension, we summarize the possible influences of long COVID on hypertension-related organs, including the cardiovascular system, kidney, and endocrine system, as well as the pathophysiological mechanisms associated with the disorders in this review. Given that the clinical course of COVID-19 is highly affected by age and sex, we also review the impacts of these factors on long COVID. Lastly, we discuss areas of uncertainty and future directions, which may lead to better understanding and improved prognosis of clinical problems associated with COVID-19.

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.

Current situation of telemedicine research for cardiovascular risk in Japan

Hypertension continues to be a principal risk factor for the occurrence of cardiovascular disorders, stroke, and kidney diseases. Although more than 40 million subjects suffer from hypertension in Japan, its optimal control is achieved only a subpopulation of patients, highlighting the need for novel approaches to manage this disorder. Toward the better control of blood pressure, the Japanese Society of Hypertension has developed the Future Plan, in which the application of the state-of-art information and communication technology, including web-based resources, artificial intelligence, and big data analysis, is considered as one of the promising solutions. In fact, the rapid advance of digital health technologies, as well as ongoing coronavirus disease 2019 pandemic, has triggered the structural changes in the healthcare system globally, increasing demand for the remote delivery of the medical services. Nonetheless, it is not entirely clear what evidence exists that support the widespread use of telemedicine in Japan. Here, we summarize the current status of telemedicine research, particularly in the field of hypertension and other cardiovascular risk factors. We note that there have been very few interventional studies in Japan that clearly showed the superiority or noninferiority of telemedicine over standard care, and that the methods of online consultation considerably varied among studies. Clearly, more evidence is necessary for wide implementation of telemedicine in hypertensive patients in Japan, and also those with other cardiovascular risk factors.

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 (MitK_ATP), 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 MitK_ATP 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 MitK_ATP 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.

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.

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.

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.

Xanthine Oxidoreductase Inhibitors Suppress the Onset of Exercise-Induced AKI in High HPRT Activity Urat1-Uox Double Knockout Mice

BACKGROUND

Hereditary renal hypouricemia type 1 (RHUC1) is caused by URAT1/SLC22A12 dysfunction, resulting in urolithiasis and exercise-induced AKI (EIAKI). However, because there is no useful experimental RHUC1 animal model, the precise pathophysiologic mechanisms underlying EIAKI have yet to be elucidated. We established a high HPRT activity Urat1-Uox double knockout (DKO) mouse as a novel RHUC1 animal model for investigating the cause of EIAKI and the potential therapeutic effect of xanthine oxidoreductase inhibitors (XOIs).

METHODS

The novel Urat1-Uox DKO mice were used in a forced swimming test as loading exercise to explore the onset mechanism of EIAKI and evaluate related purine metabolism and renal injury parameters.

RESULTS

Urat1-Uox DKO mice had uricosuric effects and elevated levels of plasma creatinine and BUN as renal injury markers, and decreased creatinine clearance observed in a forced swimming test. In addition, Urat1-Uox DKO mice had increased NLRP3 inflammasome activity and downregulated levels of Na⁺-K⁺-ATPase protein in the kidney, as Western blot analysis showed. Finally, we demonstrated that topiroxostat and allopurinol, XOIs, improved renal injury and functional parameters of EIAKI.

CONCLUSIONS

Urat1-Uox DKO mice are a useful experimental animal model for human RHUC1. The pathogenic mechanism of EIAKI was found to be due to increased levels of IL-1β via NLRP3 inflammasome signaling and Na⁺-K⁺-ATPase dysfunction associated with excessive urinary urate excretion. In addition, XOIs appear to be a promising therapeutic agent for the treatment of EIAKI.

SLC23A3 is a renal hypoxanthine transporter

LLC-PK1 renal cells show Na⁺-dependent and Na⁺-independent hypoxanthine uptake. While the latter is inhibited by adenine, neither are inhibited by xanthine. In rats, intestinal Na⁺-dependent hypoxanthine transporter Slc23a4 is not expressed in the kidney, and its action is inhibited by xanthine. This study aimed to clone Slc23a4-paralog SLC23A3 from the human kidney and investigate its hypoxanthine transport activity. We observed Na⁺-dependent 10 nM [³H]-hypoxanthine uptake in SLC23A3 RNA-injected Xenopus oocytes. Moreover, 100 μM xanthine did not inhibit Na⁺-independent 300 nM [³H]-hypoxanthine uptake, whereas 100 μM adenine did. These results confirm that SLC23A3 is a hypoxanthine transporter in the human kidney.

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.

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 novel I551F variant of the Na+/HCO3- cotransporter NBCe1-A shows reduced cell surface expression, resulting in diminished transport activity

Homozygous mutations in SLC4A4, which encodes the electrogenic Na⁺/[Formula: see text] cotransporter (NBCe1), cause proximal renal tubular acidosis associated with extrarenal symptoms. Although 17` mutated sites in SLC4A4 have thus far been identified among patients with proximal renal tubular acidosis, the physiological significance of other nonsynonymous single-nucleotide variants (SNVs) remains largely undetermined. Here, we investigated the functional properties of SNVs in NBCe1. From the National Center for Biotechnology Information dbSNP database, we identified 13 SNVs that have not previously been characterized in the highly conserved, transmembrane domains of NBCe1-A. Immunocytochemical analysis revealed that the I551F variant was present predominantly in the cytoplasm in human embryonic kidney (HEK)-293 cells, whereas all other SNVs did not show as dramatic a change in subcellular distribution. Western blot analysis in HEK-293 cells demonstrated that the I551F variant showed impaired glycosylation and a 69% reduction in cell surface levels. To determine the role of I551 in more detail, we examined the significance of various artificial mutants in both nonpolarized HEK-293 cells and polarized Madin-Darby canine kidney cells, which indicated that only I551F substitution resulted in cytoplasmic retention. Moreover, functional analysis using Xenopus oocytes demonstrated that the I551F variant had a significantly reduced activity corresponding to 39% of that of the wild-type, whereas any other SNVs and artificial I551 mutants did not show significant changes in activity. Finally, immunofluorescence experiments in HEK-293 cells indicated that the I551F variant retained wild-type NBCe1-A in the cytoplasm. These data demonstrate that the I551F variant of NBCe1-A shows impaired transport activity predominantly through cytoplasmic retention and suggest that the variant can have a dominant negative effect by forming complexes with wild-type NBCe1-A.NEW & NOTEWORTHY Electrogenic Na⁺/[Formula: see text] cotransporter 1-A (NBCe1-A) in the proximal tubule regulates the acid/base balance and fluid volume homeostasis. From the National Center for Biotechnology Information dbSNP database, we identified the I551F variant of NBCe1-A, which showed reduced glycosylation, cell surface expression, and transport activity. We also found that the I551F variant can exert a dominant negative effect on wild-type NBCe1-A, suggesting its physiological significance.

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.

Hyperkalemia in patients undergoing hemodialysis: its pathophysiology and management

Potassium is a major intracellular cation in the body, regulating membrane potential of excitable cells, such as cardiomyocytes and skeletal muscle cells. Because the kidney plays a critical role in controlling potassium balance, the elevation in serum potassium levels is one of the most common complications in patients with maintenance hemodialysis (MHD). In addition to reduced renal potassium excretion, the alteration in body potassium distribution owing to comorbid conditions may also contribute to dyskalemia. Besides potassium elimination through hemodialysis in MHD patients, accumulating data indicate the potential importance of extra‐renal elimination involving the gastrointestinal system, which can be affected by the inhibitors of the renin‐angiotensin‐aldosterone system. In this article, the literature on potassium physiology in MHD patients is reviewed with an emphasis on the changes from individuals with normal kidney function. This article also summarizes the findings of recent studies on dietary control, dialysate prescription, and pharmacological therapy.

Activation of Rac1-Mineralocorticoid Receptor Pathway Contributes to Renal Injury in Salt-Loaded db/db Mice

[Figure: see text].

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.

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.

Hypertension and related diseases in the era of COVID-19: a report from the Japanese Society of Hypertension Task Force on COVID-19

Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has affected more than seven million people worldwide, contributing to 0.4 million deaths as of June 2020. The fact that the virus uses angiotensin-converting enzyme (ACE)-2 as the cell entry receptor and that hypertension as well as cardiovascular disorders frequently coexist with COVID-19 have generated considerable discussion on the management of patients with hypertension. In addition, the COVID-19 pandemic necessitates the development of and adaptation to a “New Normal” lifestyle, which will have a profound impact not only on communicable diseases but also on noncommunicable diseases, including hypertension. Summarizing what is known and what requires further investigation in this field may help to address the challenges we face. In the present review, we critically evaluate the existing evidence for the epidemiological association between COVID-19 and hypertension. We also summarize the current knowledge regarding the pathophysiology of SARS-CoV-2 infection with an emphasis on ACE2, the cardiovascular system, and the kidney. Finally, we review evidence on the use of antihypertensive medication, namely, ACE inhibitors and angiotensin receptor blockers, in patients with COVID-19.

Rhabdomyolysis-induced acute kidney injury requiring hemodialysis after a prolonged immobilization at home in 2 morbidly obese women: case reports with literature review

Background

Rhabdomyolysis may develop into acute kidney injury (AKI), a life-threatening complication. Obese people are at risk for rhabdomyolysis due to prolonged immobilization. However, there are only a few reports of rhabdomyolysis-induced AKI due to prolonged immobilization after falls in morbidly obese people. Myoglobin is a causative compound for rhabdomyolysis-induced AKI, but the lack of treatments targeting its mechanism is a problem.

Case presentation

Two morbidly obese women (body mass index > 40.0 kg/m2) who fell on the floor at home and remained in the same posture for more than 12 h developed rhabdomyolysis-induced AKI. Both patients received aggressive fluid resuscitation but required hemodialysis because of persistent oliguria. They underwent 11 and 2 intermittent hemodialysis (HD) sessions with a conventional polymethylmethacrylate (PMMA) high-flux dialyzer, respectively, and their renal functions returned to baseline after withdrawal of HD.

Conclusions

We should be aware that morbidly obese people are at risk for rhabdomyolysis-induced AKI due to prolonged immobilization, such as after falls. At present, prophylactic renal replacement therapy (RRT) is not recommended for rhabdomyolysis. We need to reevaluate whether RRT using the appropriate membranes to effectively remove myoglobin including the PMMA membrane can improve the renal outcome in patients with rhabdomyolysis-induced AKI.

PGI2 Analog Attenuates Salt-Induced Renal Injury through the Inhibition of Inflammation and Rac1-MR Activation

Renal inflammation is known to be involved in salt-induced renal damage, leading to end-stage renal disease. This study aims to evaluate the role of inflammation in anti-inflammatory and renoprotective effects of beraprost sodium (BPS), a prostaglandin I₂ (PGI₂) analog, in Dahl salt-sensitive (DS) rats. Five-week-old male DS rats were fed a normal-salt diet (0.5% NaCl), a high-salt diet (8% NaCl), or a high-salt diet plus BPS treatment for 3 weeks. BPS treatment could inhibit marked proteinuria and renal injury in salt-loaded DS rats with elevated blood pressure, accompanied by renal inflammation suppression. Notably, high salt increased renal expression of active Rac1, followed by increased Sgk1 expressions, a downstream molecule of mineralocorticoid receptor (MR) signal, indicating salt-induced activation of Rac1-MR pathway. However, BPS administration inhibited salt-induced Rac1-MR activation as well as renal inflammation and damage, suggesting that Rac1-MR pathway is involved in anti-inflammatory and renoprotective effects of PGI₂. Based upon Rac1 activated by inflammation, moreover, BPS inhibited salt-induced activation of Rac1-MR pathway by renal inflammation suppression, resulting in the attenuation of renal damage in salt-loaded DS rats. Thus, BPS is efficacious for the treatment of salt-induced renal 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.