Rationale and design of the Japanese Biomarkers in Nephrotic Syndrome (J-MARINE) study

INTRODUCTION

Disease subtyping and monitoring are essential for the management of nephrotic syndrome (NS). Although various biomarkers for NS have been reported, their clinical efficacy has not been comprehensively validated in adult Japanese patients.

METHODS

The Japanese Biomarkers in Nephrotic Syndrome (J-MARINE) study is a nationwide, multicenter, and prospective cohort study in Japan, enrolling adult (≥18 years) patients with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), membranoproliferative glomerulonephritis (MPGN), C3 glomerulopathy (C3G), and lupus nephritis (LN). Baseline clinical information and plasma and urine samples will be collected at the time of immunosuppressive therapy initiation or biopsy. Follow-up data and plasma and urine samples will be collected longitudinally based on the designated protocols. Candidate biomarkers will be measured: CD80, cytotoxic T-lymphocyte antigen 4, and soluble urokinase plasminogen activator receptor for MCD and FSGS; anti-phospholipase A2 receptor and thrombospondin type-1 domain-containing protein 7A antibodies for MN; fragment Ba, C3a, factor I, and properdin for MPGN/C3G; and CD11b, CD16b, and CD163 for LN. Outcomes include complete and partial remission, relapse of proteinuria, a 30% reduction in estimated glomerular filtration rate (eGFR), eGFR decline, and initiation of renal replacement therapy. The diagnostic accuracy and predictive ability for clinical outcomes will be assessed for each biomarker.

RESULTS

From April 2019 to April 2023, 365 patients were enrolled: 145, 21, 138, 10, and 51 cases of MCD, FSGS, MN, MPGN/C3G, and LN, respectively.

CONCLUSION

This study will provide valuable insights into biomarkers for NS and serve as a biorepository for future studies.

Detecting and exploring kidney-derived extracellular vesicles in plasma

BACKGROUND

Extracellular vesicles (EVs) have received considerable attention as ideal biomarkers for kidney diseases. Most reports have focused on urinary EVs, that are mainly derived from the cells in the urinary tract. However, the detection and the application of kidney-derived EVs in plasma remains uncertain.

METHODS

We examined the kidney-derived small EVs (sEVs) in plasma that were supposedly released from renal mesangial and glomerular endothelial cells, using clinical samples from healthy controls and patients with kidney transplants. Plasma from healthy controls underwent ultracentrifugation, followed by on-bead flow cytometry, targeting α8 integrin, an antigen-specific to mesangial cells. To confirm the presence of kidney-derived sEVs in peripheral blood, plasma from ABO-incompatible kidney transplant recipients was ultracentrifuged, followed by western blotting for donor blood type antigens.

RESULTS

Immunohistochemistry and immunoelectron microscopy confirmed α8 integrin expression in kidney mesangial cells and their sEVs. The CD9-α8 integrin double-positive sEVs were successfully detected using on-bead flow cytometry. Western blot analysis further revealed transplanted kidney-derived sEVs containing blood type B antigens in non-blood type B recipients, who had received kidneys from blood type B donors. Notably, a patient experiencing graft kidney loss exhibited diminished signals of sEVs containing donor blood type antigens.

CONCLUSION

Our findings demonstrate the potential usefulness of kidney-derived sEVs in plasma in future research for kidney diseases.

Establishment of an adverse effect prevention protocol on plasma exchange using fresh frozen plasma prior to ABO-incompatible living donor kidney transplantation at our hospital

INTRODUCTION

Simple plasma exchange (PE) with fresh-frozen plasma replacement allows antibody removal for ABO-incompatible living donor kidney transplantation, but is associated with a high incidence of allergic reactions. We developed, implemented, and evaluated a protocol for safe preoperative PE.

METHODS

The protocol comprised pretreatment (125 mg methylprednisolone infusion, 400 mg acetaminophen and 30 mg diphenhydramine orally) with a replacement fluid rate < 20 mL/min. Allergic reaction incidence was investigated in controls who underwent ABO-incompatible living donor kidney transplantation between 2016 and March 2020 (group C) and patients who underwent the protocol and procedure between April 2020 and February 2023 (group N).

RESULTS

Ten (group C) and 19 (group N) patients performed 11 and 30 sessions of PE, respectively. Allergic reactions occurred in 81.8% and 36.7% (p = 0.014), respectively, with an odds ratio of the protocol was 0.056 (95% CI 0.0059-0.5380, P = 0.013).

CONCLUSION

Our protocol resulted in a significantly lower incidence of allergic reactions.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Basigin is released in extracellular vesicles derived from the renal tubular epithelium in response to albuminuria

AIM

Irrespective of the cause, albumin/proteinuria induces tubulointerstitial damage and accelerates the progression of kidney diseases. Our series of studies demonstrated that proteinuria, an independent prognostic factor for chronic kidney disease (CKD), is correlated with urinary basigin/CD147 (Bsg) levels. We examined the morphology and origin of Bsg in the tubular lumen through the effects of filtered glucose and protein solutes on the tubules.

METHODS

Diabetic kidney disease (DKD) patients (N = 50) were treated with spironolactone 25 mg for 4 weeks or by conservative treatment. The associations between urinary Bsg values and clinical indicators were examined. Primary-cultured proximal tubular epithelial cells (PTECs) from human adult kidneys were exposed to high glucose or bovine serum albumin (BSA).

RESULTS

In patients with early phase DKD, urinary Bsg levels were closely correlated with proteinuria but not HbA1c. Full-length Bsg on extracellular vesicles (EVs) was investigated primarily in urine collected from DKD patients. EVs obtained from the urine of DKD patients included Bsg and SGLT2 proteins. Notably, spironolactone treatment concomitantly suppressed the release of Bsg-bearing EVs in correlation with decreased albuminuria. Exposure of PTECs to BSA (but not high glucose) enhanced the storage of supernatant Bsg in EVs despite the absence of exposure-specific changes in Bsg transcription.

CONCLUSION

Proteinuria induces the release of Bsg-bearing EVs derived from PTECs into the tubular lumen.

Renal pathology in adult and paediatric population of Japan: review of the Japan renal biopsy registry database from 2007 to 2017

BACKGROUND

The Japan Renal Biopsy Registry (J-RBR), a nationwide, web-based, registry system, started in 2007. This study aimed to summarise the epidemiology of biopsy-diagnosed kidney disease in Japan over 10 years.

METHODS

We analysed the J-RBR database, from 2007 to 2017. Patients' clinical data collected at the time of biopsy and histopathological diagnoses were used for epidemiological and clinicopathologic analyses.

RESULTS

The predominant renal biopsy diagnoses were immunoglobulin A nephropathy (39.2%), lupus nephritis (6.5%) and minimal change disease (6.0%) in younger adults (19-64 years), and membranous nephropathy (17.4%), antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis (13.0%), and immunoglobulin A nephropathy (12.5%) in older adults (≥ 65 years). The percentages of patients diagnosed with membranoproliferative glomerulonephritis and immunoglobulin A nephropathy decreased, whereas those with immunoglobulin A vasculitis and diabetic nephropathy increased over the decade. In paediatric patients (< 19 years), immunoglobulin A nephropathy (36.1%), minimal change disease (17.6%), and immunoglobulin A vasculitis (8.6%) were the predominant diagnoses. The percentage of patients diagnosed with immunoglobulin A vasculitis increased over the decade. Based on the sex distribution, minimal change disease and membranous nephropathy were predominant in men aged < 20 and > 40 years, respectively, whereas immunoglobulin A vasculitis and antineutrophil cytoplasmic antibody-associated vasculitis or anti-glomerular basement membrane glomerulonephritis were predominant in women in their 20s and 30s and aged < 50 years, respectively. Immunoglobulin A nephropathy was predominant in men at most ages and in women in their 20s to 40s.

CONCLUSIONS

This study describes the distribution and changes in kidney biopsy diagnoses over 10 years in Japan and paves the way for future research on kidney diseases in adults and children.

IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium

Fibrillary glomerulonephritis (FGN), a rare disease is pathologically characterized by glomerular fibril accumulation ranging from 12 to 24 nm in diameter with negative Congo red staining. Recently, the identification of DnaJ homolog subfamily B member 9 (DNAJB9) as a highly sensitive and specific marker for FGN has revolutionized diagnosis of this disease. However, few recent studies have reported DNAJB9-negative glomerulonephritis with fibrillar deposits. As such, it remains unclear whether DNAJB9-negative cases can be considered equivalent to FGN. Here, we report the case of a 70-year-old woman who developed renal impairment and nephrotic-range proteinuria. Renal biopsy and pathological examination revealed focal glomerulonephritis with fibrocellular crescents. Immunofluorescence microscopy showed IgA-dominant deposition of polytypic IgG in the glomerulus. Electron microscopy revealed hump-like subepithelial electron dense deposits with fibrils of 15-25 nm in diameter. These findings were consistent with FGN; thus, Congo red and direct fast scarlet (DFS) staining, and immunohistochemistry for DNAJB9 were performed. In addition to negative Congo red/DFS/DNAJB9 staining, laser microdissection (LMD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) resulted negative for DNAJB9, which is a highly sensitive and specific marker for FGN. The patient's renal function further declined, prompting administration of rituximab weekly for 2 weeks, similar to the treatment for FGN. This is a unique case of IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium, unlike previous DNAJB9-negative cases. Thus, DNAJB9-negative cases diagnosed based on accurate electron microscopic evaluation must be gathered, and LMD and LC-MS/MS must be used to analyze the organized fibrillar deposits to reveal the disease entity.

Temporal Profiles of Symptom Scores After Palliative Radiotherapy for Bleeding Gastric Cancer With Adjustment for the Palliative Prognostic Index: An Exploratory Analysis of a Multicentre Prospective Observational Study (JROSG 17-3)

AIMS

Although palliative radiotherapy for gastric cancer may improve some symptoms, it may also have a negative impact due to its toxicity. We investigated whether symptoms improved after radiotherapy with adjustment for the Palliative Prognostic Index (PPI) considering that patients with limited survival tend to experience deterioration of symptoms.

MATERIALS AND METHODS

This study was an exploratory analysis of the Japanese Radiation Oncology Study Group study (JROSG 17-3). We assessed six symptom scores (nausea, anorexia, fatigue, shortness of breath, pain at the irradiated area and distress) at registration and 2, 4 and 8 weeks thereafter. We tested whether symptoms linearly improved after adjusting for the baseline PPI. Shared parameter models were used to adjust for potential bias in missing data.

RESULTS

The present study analysed all 55 patients enrolled in JROSG 17-3. With time from registration as the only explanatory variable in the model, a significant linear decrease was observed in shortness of breath, pain and distress (slopes, -0.26, -0.22 and -0.19, respectively). Given that the interaction terms (i.e. PPI × time) were not significantly associated with symptom scores in any of the six symptoms, only PPI was included as the main effect in the final multivariable models. After adjusting for the PPI, shortness of breath, pain and distress significantly improved (slope, -0.25, -0.19 and -0.17; P < 0.001, 0.002 and 0.047, respectively). An improvement in fatigue and distress was observed only in patients treated with a biologically effective dose ≤14.4 Gy.

CONCLUSION

Shortness of breath, pain and distress improved after radiotherapy. Moreover, a higher PPI was significantly associated with higher symptom scores at all time points, including baseline. In contrast, PPI did not seem to influence the improvement of these symptoms. Regardless of the expected survival, patients receiving radiotherapy for gastric cancer can expect an improvement in shortness of breath, pain and distress over 8 weeks. Multiple-fraction radiotherapy might hamper the improvement in fatigue and distress by its toxicity or treatment burden.

Systematic characterization of seed overlap microRNA cotargeting associated with lupus pathogenesis

BACKGROUND

Combinatorial gene regulation by multiple microRNAs (miRNAs) is widespread and closely spaced target sites often act cooperatively to achieve stronger repression ("neighborhood" miRNA cotargeting). While miRNA cotarget sites are suggested to be more conserved and implicated in developmental control, the pathological significance of miRNA cotargeting remains elusive.

RESULTS

Here, we report the pathogenic impacts of combinatorial miRNA regulation on inflammation in systemic lupus erythematosus (SLE). In the SLE mouse model, we identified the downregulation of two miRNAs, miR-128 and miR-148a, by TLR7 stimulation in plasmacytoid dendritic cells. Functional analyses using human cell lines demonstrated that miR-128 and miR-148a additively target KLF4 via extensively overlapping target sites ("seed overlap" miRNA cotargeting) and suppress the inflammatory responses. At the transcriptome level, "seed overlap" miRNA cotargeting increases susceptibility to downregulation by two miRNAs, consistent with additive but not cooperative recruitment of two miRNAs. Systematic characterization further revealed that extensive "seed overlap" is a prevalent feature among broadly conserved miRNAs. Highly conserved target sites of broadly conserved miRNAs are largely divided into two classes-those conserved among eutherian mammals and from human to Coelacanth, and the latter, including KLF4-cotargeting sites, has a stronger association with both "seed overlap" and "neighborhood" miRNA cotargeting. Furthermore, a deeply conserved miRNA target class has a higher probability of haplo-insufficient genes.

CONCLUSIONS

Our study collectively suggests the complexity of distinct modes of miRNA cotargeting and the importance of their perturbations in human diseases.

Protocol for a Phase 1, Open-Label, Multiple-Center, Dose-Escalation Study to Evaluate the Safety and Tolerability of ADR-001 in the Treatment of Immunoglobulin A Nephropathy

Introduction

Immunoglobulin A (IgA) nephropathy is a disease that presents with urinary symptoms such as glomerular hematuria and urinary protein positivity, with predominant deposition of IgA in the mesangial region of the glomerulus. Corticosteroids are mainly used for treatment; however, infection is a serious adverse event, and evidence regarding therapeutic efficacy is insufficient, thus new treatments are strongly desired. Mesenchymal stem cells (MSCs) contribute to the amelioration of inflammation and recovery of organ function in inflammatory environments by converting the character of leukocytes from inflammatory to anti-inflammatory and inducing the proliferation and differentiation of organ component cells, respectively. These properties of MSCs have led to their clinical application in various inflammatory diseases, but this study is the first clinical trial of MSCs for refractory glomerulonephritis in the world. This study is registered and assigned the number, jRCT2043200002 and NCT04342325.

Methods

This will be a phase 1, open-label, multiple-center, dose-escalation study of adult patients with refractory IgA nephropathy resistant to or difficult to treat with existing therapies. ADR-001 will be administered intravenously to from three to six patients at a dose of 1 × 108 cells once in the first cohort and to six patients twice at 2-week intervals in the second cohort, and observation will continue until 52 weeks. The primary endpoint will be the evaluation of adverse events up to 6 weeks after the start of ADR-001 administration. Secondary endpoints will be the respective percentages of patients with adverse events, clinical remission, partial remission, remission of urine protein, remission of hematuria, time to remission, changes in urine protein, hematuria, and estimated glomerular filtration rate.

Results

Following the administration of ADR-001 to patients with IgA nephropathy, the respective percentages of patients with adverse events, asymptomatic pulmonary emboli, clinical remission, partial remission, urine protein remission, hematuria remission, their time to remission, changes in urine protein, hematuria, and glomerular filtration rate will be determined.

Conclusion

This study will evaluate the safety and tolerability of ADR-001 and confirm its therapeutic efficacy in adult patients with refractory IgA nephropathy.

Increased Monocyte/Lymphocyte Ratio as Risk Marker for Cardiovascular Events and Infectious Disease Hospitalization in Dialysis Patients

Introduction

In dialysis patients, cardiovascular disease (CVD) and infectious disease contribute to poor clinical outcomes. We investigated if a higher monocyte/lymphocyte ratio (MLR) is associated with an increased risk of CVD events and infectious disease hospitalizations in incident dialysis patients.

Methods

In an ongoing observational prospective cohort study, 132 Japanese dialysis patients (age 58.7 ± 11.7 years; 70% men) starting dialysis therapy were enrolled and followed up for a median of 48.7 months. Laboratory biomarkers, including white blood cell count and its differential count, were determined at baseline. Event-free time and relative risks (RRs) were calculated using the Kaplan-Meier curves and Cox models, respectively.

Results

When divided into 2 groups according to median MLR (0.35 [range, 0.27–0.46]), the periods without CVD events were significantly shorter in the high MLR group than in the low MLR group (log-rank test = 5.60, p = 0.018). The RR of CVD events, after adjusting for age, sex, and diabetes, was 2.43 (1.22–4.84) in the high MLR group compared to the low MLR group. The periods without infections requiring hospitalization were also shorter (log-rank test = 4.16, p = 0.041). The RR of infections requiring hospitalization was 1.98 (1.02–3.83) after the same adjustments. The number of CVD events was higher in the high MLR group (18.6 events per 100 person-years at risk [pyr]) than the low MLR group (11.1 events per 100 pyr). The duration of infectious disease hospitalization was longer in the high MLR group (6.3 days per pyr) than in the low MLR group (2.8 days per pyr).

Conclusion

A higher MLR is associated with increased risks of both CVD events and infectious disease hospitalization in dialysis patients.

Basigin deficiency prevents anaplerosis and ameliorates insulin resistance and hepatosteatosis

Monocarboxylates, such as lactate and pyruvate, are precursors for biosynthetic pathways, including those for glucose, lipids, and amino acids via the tricarboxylic acid (TCA) cycle and adjacent metabolic networks. The transportation of monocarboxylates across the cellular membrane is performed primarily by monocarboxylate transporters (MCTs), the membrane localization and stabilization of which are facilitated by the transmembrane protein basigin (BSG). Here, we demonstrate that the MCT/BSG axis sits at a crucial intersection of cellular metabolism. Abolishment of MCT1 in the plasma membrane was achieved by Bsg depletion, which led to gluconeogenesis impairment via preventing the influx of lactate and pyruvate into the cell, consequently suppressing the TCA cycle. This net anaplerosis suppression was compensated in part by the increased utilization of glycogenic amino acids (e.g., alanine and glutamine) into the TCA cycle and by activated ketogenesis through fatty acid β-oxidation. Complementary to these observations, hyperglycemia and hepatic steatosis induced by a high-fat diet were ameliorated in Bsg-deficient mice. Furthermore, Bsg deficiency significantly improved insulin resistance induced by a high-fat diet. Taken together, the plasma membrane–selective modulation of lactate and pyruvate transport through BSG inhibition could potentiate metabolic flexibility to treat metabolic diseases.

Refractory Hypotension Caused by Selenium Deficiency in a Patient on Peritoneal Dialysis

Selenium is essential for human health; its deficiency leads to cardiac dysfunction. We herein report a 79-year-old man on peritoneal dialysis who presented with refractory hypotension caused by selenium deficiency. He was admitted to our hospital with bacterial pneumonia and hypotension and abnormal electrocardiogram (ECG) findings. Despite improvement of pneumonia, his hypotension continued, and intravenous noradrenalin could not be discontinued. His serum selenium level was extremely low, and he was started on intravenous selenium. His hypotension and ECG findings gradually improved, and noradrenalin was discontinued. Physicians should consider selenium deficiency when patients on peritoneal dialysis show refractory hypotension.

Acquired Fanconi Syndrome in a Patient with Nontyphoidal Salmonella Bacteremia

Nontyphoidal Salmonella is a common cause of bacterial gastroenteritis, occasionally causing bacteremia. We herein report the case of an 80-year-old man who presented with bacteremia and pre-renal acute kidney injury (AKI) secondary to diarrhea caused by nontyphoidal Salmonella. Despite AKI improvement on fluid administration, some serological abnormalities, such as hypokalemia, hypophosphatemia, and hypouricemia, and abnormal urinary findings emerged, including renal glycosuria and aminoaciduria. Fractional excretion of phosphate and uric acid was increased, suggesting that the serological and urinary abnormalities may have arisen from Fanconi syndrome. Physicians should consider acquired Fanconi syndrome when patients with nontyphoidal Salmonella bacteremia present with electrolyte disorders.

Efficacy of favipiravir for an end stage renal disease patient on maintenance hemodialysis infected with novel coronavirus disease 2019

BACKGROUND

Novel coronavirus disease 2019 (COVID-19) refers to infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogen, and has spread to pandemic levels since its inception in December 2019. While several risk factors for severe presentation have been identified, the clinical course for end-stage renal disease (ESRD) patients on maintenance hemodialysis with COVID-19 has been unclear. Previous studies have revealed that some antiviral agents may be effective against COVID-19 in the general population, but the pharmacokinetics and pharmacodynamics of these agents in ESRD patients remain under investigation. Favipiravir, an antiviral agent developed for treatment of influenza, is one candidate treatment for COVID-19, but suitable dosages for patients with renal insufficiency are unknown. Here we provide a first report on the efficacy of favipiravir in a patient with ESRD undergoing hemodialysis.

CASE PRESENTATION

The case involved a 52-year-old woman with COVID-19 who had been undergoing maintenance hemodialysis three times a week for 3 years due to diabetic nephropathy. She had initially been treated with lopinavir/ritonavir and ciclesonide for 5 days, but developed severe pneumonia requiring invasive positive-pressure ventilation. Those antiviral agents were subsequently switched to favipiravir. She recovered gradually, and after 2 weeks was extubated once the viral load of SARS-CoV-2 fell below the limit of detection. Although concentrations of several biliary enzymes were elevated, no major adverse events were observed.

CONCLUSION

Favipiravir may be an effective option for the treatment of COVID-19-infected patients with ESRD.

A Prospective, Randomized Clinical Trial of Etelcalcetide in Patients Receiving Hemodialysis With Secondary Hyperparathyroidism (the DUET Trial)

INTRODUCTION

The clinical trial on the Development of a treatment strategy for chronic kidney disease‒mineral and bone disorder by a mUltilateral mechanism of ETelcalcetide hydrochloride, or the DUET trial, was designed to determine the efficacy of etelcalcetide, an intravenous calcimimetic, for control of secondary hyperparathyroidism (SHPT).

METHODS

Eligible SHPT maintenance hemodialysis patients (n = 124) were randomized (1:1:1) for inclusion in the DUET trial, a 12-week, multicenter, open-label, parallel-group study (jRCTs041180108), and assigned to either an etelcalcetide + active vitamin D group (group E+D), an etelcalcetide + oral calcium preparation group (group E+Ca), or a control group (group C). The primary endpoint was number of patients with a 50% reduction from baseline of intact parathyroid hormone (iPTH) levels, and iPTH levels ≤ 240 pg/mL at 12 weeks after start of the trial.

RESULTS

The proportion of patients reaching the primary endpoint (95% confidence interval [CI]) was 90.0% (76.3%-97.2%) in group E+D, 56.8% (39.5%-72.9%) in group E+Ca, and 19.5% (8.8%-34.9%) in group C. Etelcalcetide treatment led to a significant increase in the number of patients achieving the endpoint (odds ratio, 13.4; 95% CI, 5.10-35.3) on logistic regression analysis, with iPTH, corrected serum calcium, and phosphate at baseline as covariates. Significantly more patients achieved the endpoint in group E+D compared with group E+Ca (odds ratio, 6.35; 95% CI, 1.79-22.48). There were fewer hypocalcemic visits in group E+D compared with group E+Ca (P = 0.018), yet the former group was prone to hyperphosphatemia.

CONCLUSION

Etelcalcetide showed good control of iPTH for maintenance hemodialysis patients with SHPT. Active vitamin D was useful in correcting hypocalcemia, but the oral calcium preparation was superior for suppression of hyperphosphatemia.

The effect of maintaining high hemoglobin levels on long-term kidney function in kidney transplant recipients: a randomized controlled trial

Background

Posttransplant anemia may be a major determinant of chronic allograft nephropathy. However, the impact of correcting anemia on graft function remains controversial.

Methods

A 3-year follow-up of an open-label, multicenter, randomized controlled trial involving kidney transplantation recipients examined whether sustained maintenance of target hemoglobin (Hb) concentrations at a high level (12.5–13.5 g/dL, n = 64) with either darbepoetin alfa or epoetin beta pegol would slow the graft function decline rate as the primary efficacy endpoint, compared with maintenance of a low Hb concentration (10.5–11.5 g/dL, n = 63).

Results

The mean blood pressures in the two groups were well controlled throughout the study. In the high Hb group, mean Hb concentrations increased to >12 g/dL at 3 months, reaching the target range at 18 months. At the end of this study (36 months), the mean Hb concentration was 12.8 ± 0.7 g/dL in the high Hb group and 11.5 ± 1.2 g/dL in the low Hb group. The decline rate of the estimated glomerular filtration (eGFR) rate was considerably greater in the low Hb group (ΔeGFR, −5.1 ± 9.5 mL/min/1.73 m²) than in the high Hb group (−1.0 ± 8.4 mL/min/1.73 m²) (P = 0.02). Of note, only a few high Hb patients developed cardiovascular events and returned to hemodialysis, but the low Hb patients did not.

Conclusion

This prospective study suggests that correcting anemia to the target Hb level range (12.5–13.5 g/dL) slows renal function deterioration by >3 years in the chronic phase of allograft nephropathy.

Successful Introduction of Peritoneal Dialysis in an End-stage Renal Failure Patient with Idiopathic Aplastic Anemia

A 45-year-old man with idiopathic aplastic anemia required renal replacement therapy (RRT) due to end-stage renal disease (ESRD). We succeeded in inserting the peritoneal dialysis (PD) catheter under cover of frequent red blood cell and platelet infusions because of severe pancytopenia. During the one-year period after starting PD using an ultraviolet-ray sterilization device, he developed severe leukopenia but no PD-related peritonitis or exit site/tunnel infection until he died of pneumonia. This case suggests that PD might be a suitable choice as RRT in ESRD patients with aplastic anemia, even in those with severe pancytopenia.

Circulating levels of CD34+ cells predict long-term cardiovascular outcomes in patients on maintenance hemodialysis

CD34+ cells maintain vascular homeostasis and predict cardiovascular outcomes. We previously evaluated the association of CD34+ cells with cardiovascular disease (CVD) events over 23 months, but long-term CVD outcomes in relation to levels of CD34+ cells in patients on maintenance hemodialysis are unclear. Herein, we analyzed the long-term predictive potential levels of CD34+ cells for CVD outcomes and all-cause mortality. Between March 2005 and May 2005, we enrolled 215 patients on maintenance hemodialysis at Nagoya Kyoritsu Hospital and followed them up to 12.8 years. According to the CD34+ cell counts, patients were classified into the lowest, medium, and highest tertiles. Levels of CD34+ cells were analyzed in association with four-point major adverse CV events (MACEs), CVD death, and all-cause mortality. In univariate analysis age, smoking habit, lower geriatric nutrition risk index, lower calcium × phosphate product, and lower intact parathyroid hormone were significantly associated with the lowest tertile. Whereas, in multivariate analysis, age and smoking habit were significantly associated with the lowest tertile. Among 139 (64.7%) patients who died during a mean follow-up period of 8.0 years, 39 (28.1%) patients died from CVD. Patients in the lowest tertile had a significantly lower survival rate than those in the medium and highest tertiles (p ≤ 0.001). Using multivariable analyses, the lowest tertile was significantly associated with four-point MACEs (hazard ratio 1.80, p = 0.023) and CVD death (hazard ratio 2.50, p = 0.011). In conclusion, our long-term observational study revealed that a low level of CD34+ cells in the circulation predicts CVD outcomes among patients on maintenance hemodialysis.

Increase of core temperature affected the progression of kidney injury by repeated heat stress exposure

An epidemic of chronic kidney disease of unknown etiology (Mesoamerican nephropathy) has emerged in hot regions of Central America. We have demonstrated that dehydration associated with recurrent heat exposure causes chronic kidney disease in animal models. However, the independent influence of core body temperature on kidney injury has not been explored. In the present study, we tested the hypothesis that kidney injury could be accelerated by increasing body temperature independent of external temperature. Wild-type mice were exposed to heat (39.5°C, 30 min, 2 times daily) with or without the mitochondrial uncoupling agent 2,4-dinitrophenol (DNP) for 10 days. Core temperature, renal function, proteinuria, and renal histological and biochemical analyses were performed. Isolated mitochondria markers of oxidative stress were evaluated from kidney tissue. DNP increased body core temperature in response to heat by 1°C (42 vs. 41°C), which was transient. The mild increase in temperature correlated with worsening albuminuria (R = 0.715, P < 001), renal tubular injury, and interstitial infiltration of monocytes/macrophages. Tubular injury was marked in the outer medulla. This was associated with a reduction in kidney tissue ATP levels (nonheated control: 16.71 ± 1.33 nmol/mg and DNP + heat: 13.08 ± 1.12 nmol/mg, P < 0.01), reduced mitochondria, and evidence for mitochondrial oxidative stress. The results of the present study suggest that kidney injury in heat stress is markedly worsened by increasing core temperature. This is consistent with the hypothesis that clinical and subclinical heat stroke may play a role in Mesoamerican nephropathy.

CD147/Basigin Deficiency Prevents the Development of Podocyte Injury through FAK Signaling

Podocytes, which are susceptible to injury by various stimuli and stress, are critical regulators of proteinuric kidney diseases, regardless of the primary disease and pathogenesis. We further confirmed a significant correlation between urinary CD147/basigin (Bsg) levels and proteinuria in patients with focal segmental glomerulosclerosis. However, the molecular mechanism of podocyte injury involving Bsg is not fully understood. Here, the involvement of Bsg in the pathogenesis of podocyte injury was elucidated. Healthy podocytes rarely express Bsg protein. In two independent mouse models, including adriamycin-induced nephropathy and N^ω-nitro-l-arginine methyl ester (l-name)-induced endothelial dysfunction, Bsg induction in injured podocytes caused podocyte effacement, which led to development of proteinuria. Bsg silencing in cultured podocytes exposed to transforming growth factor-β suppressed focal adhesion rearrangement and cellular motility via the activation of β₁ integrin-focal adhesion kinase-matrix metallopeptidase signaling. In addition, induction of vascular endothelial growth factor and endothelin-1, which are implicated in podocyte-to-endothelial cross-communication, was lower in the supernatants of cultured Bsg-silenced podocytes stimulated with transforming growth factor-β. In this setting, Bsg may be involved in a physiological positive feedback loop that accelerates podocyte cell motility and depolarization. The current study thus suggests that Bsg silencing via suppression of β₁ integrin-focal adhesion kinase-matrix metallopeptidase signaling may be an attractive therapeutic strategy for the maintenance of podocytes in patients with proteinuric kidney diseases.

The Accumulation of Heparan Sulfate S-Domains in Kidney Transthyretin Deposits Accelerates Fibril Formation and Promotes Cytotoxicity

The highly sulfated domains of heparan sulfate (HS), alias HS S-domains, are made up of repeated trisulfated disaccharide units [iduronic acid (2S)-glucosamine (NS, 6S)] and are selectively remodeled by extracellular endoglucosamine 6-sulfatases (Sulfs). Although HS S-domains are critical for signal transduction of several growth factors, their roles in amyloidoses are not yet fully understood. Herein, we found HS S-domains in the kidney of a patient with transthyretin amyloidosis. In in vitro assays with cells stably expressing human Sulfs, heparin, a structural analog of HS S-domains, promoted aggregation of transthyretin in an HS S-domain-dependent manner. Interactions of cells with transthyretin fibrils and cytotoxicity of these fibrils also depended on HS S-domains at the cell surface. Furthermore, glypican-5, encoded by the susceptibility gene for nephrotic syndrome GPC5, was found to be accumulated in the transthyretin amyloidosis kidney. Our study, thus, provides a novel insight into the pathologic roles of HS S-domains in amyloidoses, and we propose that enzymatic remodeling of HS chains by Sulfs may offer an effective approach to inhibiting formation and cytotoxicity of amyloid fibrils.

Therapeutic efficacy of rituximab for the management of adult-onset steroid-dependent nephrotic syndrome: a retrospective study

BACKGROUND

Recent reports have described the efficacy of rituximab in treating steroid-dependent nephrotic syndrome (SDNS) in pediatric patients. However, few reports describe data regarding adult-onset SDNS. We investigated the efficacy of rituximab for the management of adult-onset SDNS.

METHODS

We performed a retrospective cohort study investigating eight patients with adult-onset SDNS who were treated with rituximab. Clinical data were obtained at the initiation of rituximab therapy. The primary outcomes evaluated were successful suppression of relapses and CD19+ cells after rituximab treatment. The corticosteroid- and immunosuppressant-sparing effect and adverse events were additionally evaluated.

RESULTS

All eight patients were diagnosed with minimal change nephrotic syndrome and received immunosuppressants in addition to corticosteroid. Total number of relapses was 10.5 times as a median value. Rituximab administration was repeated in two patients, whereas six received single-dose rituximab. Three of eight (37.5%) patients showed relapse after rituximab therapy. A rituximab-induced depletion in CD19+ cells noted initially was followed by their reappearance in all patients. There were cases with no relapse after the reappearance of CD19+ cells. The median relapse time pre- and post-rituximab therapy showed a decrease from 1 time/year (interquartile range [IQR] 1-3 times/year) to 0 time/year (IQR 0-1 time/year). Rituximab treatment induced a significant reduction in the required doses of corticosteroid and cyclosporine (P < 0.01). No serious adverse events were observed.

CONCLUSION

Rituximab treatment was effective not only in childhood-onset but also in adult-onset SDNS. Further studies are needed to establish optimal treatment regimens.

Lacking ketohexokinase-A exacerbates renal injury in streptozotocin-induced diabetic mice

OBJECTIVE

Ketohexokinase (KHK), a primary enzyme in fructose metabolism, has two isoforms, namely, KHK-A and KHK-C. Previously, we reported that renal injury was reduced in streptozotocin-induced diabetic mice which lacked both isoforms. Although both isoforms express in kidney, it has not been elucidated whether each isoform plays distinct roles in the development of diabetic kidney disease (DKD). The aim of the study is to elucidate the role of KHK-A for DKD progression.

MATERIALS AND METHODS

Diabetes was induced by five consecutive daily intraperitoneal injections of streptozotocin (50 mg/kg) in C57BL/6J wild-type mice, mice lacking KHK-A alone (KHK-A KO), and mice lacking both KHK-A and KHK-C (KHK-A/C KO). At 35 weeks, renal injury, inflammation, hypoxia, and oxidative stress were examined. Metabolomic analysis including polyol pathway, fructose metabolism, glycolysis, TCA (tricarboxylic acid) cycle, and NAD (nicotinamide adenine dinucleotide) metabolism in kidney and urine was done.

RESULTS

Diabetic KHK-A KO mice developed severe renal injury compared to diabetic wild-type mice, and this was associated with further increases of intrarenal fructose, dihydroxyacetone phosphate (DHAP), TCA cycle intermediate levels, and severe inflammation. In contrast, renal injury was prevented in diabetic KHK-A/C KO mice compared to both wild-type and KHK-A KO diabetic mice. Further, diabetic KHK-A KO mice contained decreased renal NAD⁺ level with the increase of renal hypoxia-inducible factor 1-alpha expression despite having increased renal nicotinamide (NAM) level.

CONCLUSION

These results suggest that KHK-C might play a deleterious role in DKD progression through endogenous fructose metabolism, and that KHK-A plays a unique protective role against the development of DKD.

Purification and Some Chemical Properties of Thrombin-Like Enzyme from Trimeresurus Flavoviridis Venom

There has been no previous report indicating whether thrombin-like enzyme is contained in the venomof Trimeresurus flavoviridis whichhas the strongest toxic effect in the case of Habu bite. The presentstudy was undertaken to clarify the existence of thrombin-like enzyme in Trimeresurus flavoviridis venom. As a starting material, lyophilized crude venom of Trimeresurus flavoviridis was used, and ammonium sulphate fractionation, gel filtration using Sephadex G-25, Sephadex G-150 and arginine-Sepharose affinity chromatography were carried out to separate and purify a thrombin-like enzyme from the crude venom. The enzyme was purified to a 137-fold increase in specific activity and the purified preparation revealed a single band on SDS-PAGE. The molecular weight of the enzyme was estimated to be 65,000-70,000 daltons by means of SDS-PAGE and gel filtration, and its isoelectric point was pH 4.5-5.5. Furthermore, the optimal pH of the enzyme was in the range of pH 8.0 to 8.5. Some of the differences in enzymatic properties between this enzyme and bovine thrombin were studied. The snake enzyme could coagulate only rabbit plasma and convert only purified rabbit fibrinogen to fibrin gel. In addition, this thrombin-like enzyme released only fibrinopeptide A from purified rabbit fibrinogen and did not release fibrinopeptide B.

Investigation on the benefits of mycophenolate mofetil and therapeutic drug monitoring in the treatment of Japanese patients with lupus nephritis

BACKGROUND

Mycophenolate mofetil (MMF) is recommended as a first-line immunosuppressant to treat lupus nephritis (LN). Prognosis and therapeutic response in LN are known to vary depending on race. We investigated the benefits of MMF and therapeutic drug monitoring (TDM) in the treatment of Japanese LN patients.

METHODS

In this retrospective cohort study, a total of 20 patients with LN who started MMF treatment were included. Clinical data were collected regularly after MMF administration. We evaluated complete remission (CR) rate as the primary outcome. Predictors of CR were identified using univariate and multivariate analyses. In the research of TDM, the correlation with the area under the curve (AUC) was analyzed at MMF dose, single-point value, treatment response, and adverse events.

RESULTS

Overall, 70% of cases showed CR; both flare-ups and refractory cases had favorable results. Cases of LN with nephrotic syndrome (NS) or class III/IV + V showed a significantly lower CR rate (p < 0.005). The ratio of maintaining CR after MMF therapy was as high as 85.7%. In multivariate analysis, NS was an independent negative predictor of CR (HR 0.09, 95% confidence interval 0.01-0.81; p = 0.03). The relationship between AUC and MMF dose was low, and AUC correlated with trough level (r = 0.73). AUC tended to be high in the treatment responder (p = 0.09), but did not correlate with adverse events of infection (p = 0.92).

CONCLUSION

MMF is a beneficial treatment option for Japanese LN patients, and further investigation on TDM-based therapy is needed.

The clinical relevance of plasma CD147/basigin in biopsy-proven kidney diseases

BACKGROUND

Precise understanding of kidney disease activity is needed to design therapeutic strategies. CD147/basigin is involved in the pathogenesis of acute kidney injury and renal fibrosis through inflammatory cell infiltration. The present study examined the clinical relevance of CD147 in biopsy-proven kidney diseases that lead to the progression of chronic kidney disease.

METHODS

Kidney biopsy specimens and plasma and urine samples were obtained from patients with kidney diseases, including IgA nephropathy (IgAN), Henoch-Schönlein purpura nephritis (HSPN), diabetic kidney disease (DKD), focal segmental glomerulosclerosis (FSGS), and membranous nephropathy (MN), who underwent renal biopsy between 2011 and 2014. Plasma and urinary CD147 levels were measured and evaluated for their ability to reflect histological features. Disease activity of IgAN tissues was evaluated according to the Oxford classification and the Japanese histological grading system.

RESULTS

In biopsy tissues, CD147 induction was detected in injured lesions representing renal inflammation. Plasma CD147 values correlated with eGFR in patients with inflammation-related kidney diseases such as IgAN, HSPN, and DKD. Particularly in IgAN patients, plasma CD147 levels were correlated with injured regions comprising more than 50% of glomeruli or with tubular atrophy/interstitial injury in biopsy tissues. Proteinuria showed a closer correlation with urinary values of CD147 and L-FABP. Of note, plasma and urinary CD147 levels showed a strong correlation with eGFR or proteinuria, respectively, only in DKD patients.

CONCLUSION

Evaluation of plasma and urinary CD147 levels might provide key insights for the understanding of the activity of various kidney diseases.

Single-dose Rituximab Therapy for Refractory Idiopathic Membranous Nephropathy: A Single-center Experience

To date, a recognized treatment for refractory membranous nephropathy (MN) has not been established. Recently, several reports have indicated the efficacy of rituximab as a novel treatment option. However, only a few published accounts exist of rituximab therapy for idiopathic MN (IMN) in the Asian population. We present the cases of three IMN patients who were treated with single-dose rituximab after they showed no response to conventional therapies, including corticosteroids, cyclosporine, cyclophosphamide, mizoribine, and mycophenolate mofetil. Although one case showed no response, a complete or incomplete remission was achieved in the other two cases. Rituximab may therefore be a beneficial treatment option for IMN.

Urinary soluble CD163 level reflects glomerular inflammation in human lupus nephritis

BACKGROUND

In addition to classically activated macrophages that have effector roles in tissue injury, alternatively activated M2 macrophages are involved in the resolution of inflammation in animal models of kidney disease. To clarify the clinical relevance of macrophage phenotypes in human glomerular diseases, we evaluated the renal accumulation of macrophages and plasma and urine levels of CD163, an M2 marker, in lupus nephritis (LN) patients.

METHODS

Kidney biopsies and plasma and urine samples were obtained from LN patients who underwent renal biopsy between 2008 and 2012. CD163⁺, CD68⁺ and CD204⁺ cells were counted in paraffin-embedded and frozen sections. LN histological activity was evaluated semiquantitatively using the biopsy activity index. Plasma and urinary soluble CD163 (sCD163) concentrations were also measured and evaluated for their significance as potential LN biomarkers.

RESULTS

Immunohistological analysis of glomeruli from LN patients revealed that >60% of CD68⁺ macrophages had merged with CD163⁺ cells. The increased number of glomerular CD163⁺ macrophages was correlated with LN severity, as determined by the biopsy active index (r = 0.635). Urinary (u-) sCD163 level was strongly correlated with glomerular CD163⁺ cell counts and histological disease score as well as urinary monocyte chemoattractant protein 1 levels (r = 0.638 and 0.592, respectively). Furthermore, the u-sCD163 level was higher in patients with active LN than in those with other diseases.

CONCLUSIONS

Glomerular CD163⁺ macrophages are the predominant phenotype in the kidneys of lupus patients. These findings indicate that the u-sCD163 level can serve as a biomarker for macrophage-dependent glomerular inflammation in human LN.

Randomized control trial for the assessment of the anti-albuminuric effects of topiroxostat in hyperuricemic patients with diabetic nephropathy (the ETUDE study)

Proteinuria is an established risk factor for diabetic nephropathy. Recent studies indicate that some xanthine oxidase inhibitors have a renoprotective effect. The aim of this study was to assess whether topiroxostat reduces albuminuria in hyperuricemic patients with diabetic nephropathy and overt proteinuria. The ETUDE study is an ongoing 24-week, multicenter, open-label, randomized (1:1), parallel group study involving hyperuricemic patients with diabetic nephropathy (estimated glomerular filtration rate [eGFR] ≥ 20 mL/min/1.73 m(2)) and overt proteinuria (0.3 ≤ urine protein to creatinine ratio (UPCR) < 3.5 g/g Cr). Patients are randomly assigned to high dose (topiroxostat 160 mg daily) or low dose (topiroxostat 40 mg daily) on top of standard of care. The primary endpoint is the change in albuminuria indicated by urine albumin-to-creatinine ratio after 24 treated weeks relative to the baseline values. This trial was registered at the Japanese University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR: UMIN 000015403). The background, rationale, and study design of this trial are presented here. Seventy-six patients from four registered facilities have already been enrolled and received at least one dose of topiroxostat. This trial will end in 2017. The ETUDE trial is the first randomized controlled study of topiroxostat in hyperuricemic patients with diabetic nephropathy and overt proteinuria. We will clarify the pleiotropic function of topiroxostat including an anti-albumiuric effect as well as its effects on safely decreasing serum uric acid levels.

Therapeutic Potential of Stem Cells from Human Exfoliated Deciduous Teeth in Models of Acute Kidney Injury

Background

Acute kidney injury (AKI) is a critical condition associated with high mortality. However, the available treatments for AKI are limited. Stem cells from human exfoliated deciduous teeth (SHED) have recently gained attention as a novel source of stem cells. The purpose of this study was to clarify whether SHED have a therapeutic effect on AKI induced by ischemia-reperfusion injury.

Methods

The left renal artery and vein of the mice were clamped for 20 min to induce ischemia. SHED, bone marrow derived mesenchymal stem cells (BMMSC) or phosphate-buffered saline (control) were administered into the subrenal capsule. To confirm the potency of SHED in vitro, H₂O₂ stimulation assays and scratch assays were performed.

Results

The serum creatinine and blood urea nitrogen levels of the SHED group were significantly lower than those of the control group, while BMMSC showed no therapeutic effect. Infiltration of macrophages and neutrophils in the kidney was significantly attenuated in mice treated with SHED. Cytokine levels (MIP-2, IL-1β, and MCP-1) in mice kidneys were significantly reduced in the SHED group. In in vitro experiments, SHED significantly decreased MCP-1 secretion in tubular epithelial cells (TEC) stimulated with H₂O₂. In addition, SHED promoted wound healing in the scratch assays, which was blunted by anti-HGF antibodies.

Discussion

SHED attenuated the levels of inflammatory cytokines and improved kidney function in AKI induced by IRI. SHED secreted factors reduced MCP-1 and increased HGF expression, which promoted wound healing. These results suggest that SHED might provide a novel stem cell resource, which can be applied for the treatment of ischemic kidney injury.

CD147/basigin limits lupus nephritis and Th17 cell differentiation in mice by inhibiting the interleukin-6/STAT-3 pathway

OBJECTIVE

Interleukin-17 (IL-17)-producing T cells (Th17 cells) play critical roles in the pathogenesis of immune-related diseases, including systemic lupus erythematosus. However, the fundamental mechanism regulating Th17 cell differentiation is not fully understood. Recently, we demonstrated that plasma levels of CD147/basigin (Bsg) in patients with lupus nephritis (LN) were closely associated with disease activity. but the molecular mechanism involving Bsg has been elusive. Here, we addressed the role of Bsg in the pathogenesis of LN.

METHODS

Injections of pristane (2,6,10,14-tetramethylpentadecane [TMPD]) were administered to Bsg(-/-) or Bsg(+/+) mice to induce LN. The mice were killed 6 months after being injected, for histologic and biochemical analyses of the kidneys and spleens.

RESULTS

Pristane induced LN more strikingly in Bsg(-/-) mice than in Bsg(+/+) mice, even though humoral autoimmunity was similarly increased in both genotypes. The increased number of Th17, but not Th1, Treg cells, was augmented in Bsg(-/-) mice. The expression of IL-17 was also increased in the kidneys of Bsg(-/-) mice, in proportion to LN disease activity. Furthermore, treatment with anti-IL-17 antibody reduced LN disease activity in Bsg(-/-) mice. Complementary to these phenotypes of Bsg(-/-) mice, Bsg expression was enhanced in activated CD4+ T cells in vivo and in vitro. Bsg deficiency selectively augmented in vitro differentiation of naive CD4+ T cells to Th17 cells and STAT-3 phosphorylation during this differentiation. Moreover, STAT-3 phosphorylation was suppressed by crosslinking of Bsg with its antibody.

CONCLUSION

Bsg plays an indispensable role in Th17 cell differentiation as a negative regulator by suppressing the IL-6/STAT-3 pathway.

Increase of Antimyeloperoxidase Antineutrophil Cytoplasmic Antibody (ANCA) in Patients with Renal ANCA-associated Vasculitis: Association with Risk to Relapse

Objective.

The diagnostic values of antiproteinase 3 and antimyeloperoxidase tests using antineutrophil cytoplasmic antibodies (ANCA) are well established. Our study determined whether an increase in ANCA level was a predictor of disease flareup.

Methods.

Our study included 126 patients with ANCA-associated renal vasculitis treated at 9 nephrology centers in Japan. The relationship between increased ANCA levels and relapse was assessed using time-dependent multivariate Cox regression models adjusted for clinically relevant factors. The outcome of interest was the time from remission to first relapse.

Results.

During the observation period [median 41 mos, interquartile range (IQR) 23–66 mos], 118 patients (95.8%) achieved remission at least once. After achieving remission, 34 patients relapsed (21.7%). Time-dependent multivariate Cox regression models revealed that lung involvement (adjusted HR 2.29, 95% CI 1.13–4.65, p = 0.022) and increased ANCA levels (adjusted HR 17.4, 95% CI 8.42–36.0, p < 0.001) were significantly associated with relapse. The median time from ANCA level increase to relapse was 0.6 months (IQR 0–2.1 mos).

Conclusion.

In our study, an increase in ANCA level during remission was associated with a risk of disease relapse. A rise in ANCA level may be useful for guiding treatment decisions in appropriate subsets of patients with ANCA-associated vasculitis.