Predominant CD8+ cell infiltration and low accumulation of regulatory T cells in immune checkpoint inhibitor-induced tubulointerstitial nephritis.

Immune checkpoint inhibitors (ICIs) can provide survival benefits to cancer patients; however, they sometimes result in the development of renal immune-related adverse events (irAEs). Tubulointerstitial nephritis (TIN) is the most representative pathological feature of renal irAEs. However, the clinicopathological entity and underlying pathogenesis of ICI-induced TIN are unclear. Therefore, we compared the clinical and histological features of this condition with those of non-ICI drug-induced TIN. Age and C-reactive protein levels were significantly higher in ICI-induced TIN, but there were no significant differences in renal function. Immunophenotyping of ICI-induced TIN showed massive T cell and macrophage infiltration with fewer B cells, plasma cells, neutrophils, and eosinophils. Compared with those in non-ICI drug-induced TIN, CD4+ cell numbers were significantly lower in ICI-induced TIN but CD8+ cell numbers were not significantly different. However, CD8/CD3 and CD8/CD4 ratios were higher in ICI-induced TIN. Moreover, CD25+ and FOXP3+ cells, namely regulatory T cells, were less abundant in ICI-induced TIN. In conclusion, T cell, B cell, plasma cell, neutrophil, and eosinophil numbers proved useful for differentiating ICI-induced and non-ICI drug-induced TIN. Furthermore, the predominant distribution of CD8+ cells and low accumulation of regulatory T cells might be associated with ICI-induced TIN development.

Inhibition of Transglutaminase 2 Reduces Peritoneal Injury in a Chlorhexidine-Induced Peritoneal Fibrosis Model.

Long-term peritoneal dialysis (PD) is often associated with peritoneal dysfunction leading to withdrawal from PD. The characteristic pathologic features of peritoneal dysfunction are widely attributed to peritoneal fibrosis and angiogenesis. The detailed mechanisms remain unclear, and treatment targets in clinical settings have yet to be identified. We investigated transglutaminase 2 (TG2) as a possible novel therapeutic target for peritoneal injury. TG2 and fibrosis, inflammation, and angiogenesis were investigated in a chlorhexidine gluconate (CG)-induced model of peritoneal inflammation and fibrosis, representing a noninfectious model of PD-related peritonitis. Transforming growth factor (TGF)-ß type I receptor (TGFßR-I) inhibitor and TG2-knockout mice were used for TGF-ß and TG2 inhibition studies, respectively. Double immunostaining was performed to identify cells expressing TG2 and endothelial-mesenchymal transition (EndMT). In the rat CG model of peritoneal fibrosis, in situ TG2 activity and protein expression increased during the development of peritoneal fibrosis, as well as increases in peritoneal thickness and numbers of blood vessels and macrophages. TGFßR-I inhibitor suppressed TG2 activity and protein expression, as well as peritoneal fibrosis and angiogenesis. TGF-ß1 expression, peritoneal fibrosis, and angiogenesis were suppressed in TG2-knockout mice. TG2 activity was detected by α-smooth muscle actin-positive myofibroblasts, CD31-positive endothelial cells, and ED-1-positive macrophages. CD31-positive endothelial cells in the CG model were α-smooth muscle actin-positive, vimentin-positive, and vascular endothelial-cadherin-negative, suggesting EndMT. In the CG model, EndMT was suppressed in TG2-knockout mice. TG2 was involved in the interactive regulation of TGF-ß. As inhibition of TG2 reduced peritoneal fibrosis, angiogenesis, and inflammation associated with TGF-ß and vascular endothelial growth factor-A suppression, TG2 may provide a new therapeutic target for ameliorating peritoneal injuries in PD.

Tissue Sodium Accumulation Induces Organ Inflammation and Injury in Chronic Kidney Disease.

High salt intake is a primary cause of over-hydration in chronic kidney disease (CKD) patients. Inflammatory markers are predictors of CKD mortality; however, the pathogenesis of inflammation remains unclear. Sodium storage in tissues has recently emerged as an issue of concern. The binding of sodium to tissue glycosaminoglycans and its subsequent release regulates local tonicity. Many cell types express tonicity-responsive enhancer-binding protein (TonEBP), which is activated in a tonicity-dependent or tonicity-independent manner. Macrophage infiltration was observed in the heart, peritoneal wall, and para-aortic tissues in salt-loading subtotal nephrectomized mice, whereas macrophages were not prominent in tap water-loaded subtotal nephrectomized mice. TonEBP was increased in the heart and peritoneal wall, leading to the upregulation of inflammatory mediators associated with cardiac fibrosis and peritoneal membrane dysfunction, respectively. Reducing salt loading by a diuretic treatment or changing to tap water attenuated macrophage infiltration, TonEBP expression, and inflammatory marker expression. The role of TonEBP may be crucial during the cardiac fibrosis and peritoneal deterioration processes induced by sodium overload. Anti-interleukin-6 therapy improved cardiac inflammation and fibrosis and peritoneal membrane dysfunction. Further studies are necessary to establish a strategy to regulate organ dysfunction induced by TonEBP activation in CKD patients.

Interleukin-6 blockade reduces salt-induced cardiac inflammation and fibrosis in subtotal nephrectomized mice.

Cardiovascular disease is the most common comorbidity in patients with chronic kidney disease (CKD), affecting both their prognosis and quality of life. Cardiac fibrosis is common in patients with CKD with left ventricular diastolic dysfunction, and it is associated with increased risk of heart failure and mortality. Recent evidence suggests that high salt intake activates immune responses associated with local accumulation of sodium. We reported that high salt intake promotes cardiac inflammation in subtotal nephrectomized (Nx) mice. We investigated the effects of administration of MR16-1, a rat anti-mouse monoclonal interleukin (IL)-6 receptor antibody, in Nx mice with salt loading (Nx-salt). Expression of monocyte chemoattractant protein-1, tumor necrosis factor-α, IL-1ß, and IL-6 mRNAs and macrophage infiltration was significantly reduced in the heart of Nx-salt mice treated with MR16-1 (Nx-salt-MR16-1) compared with Nx-salt mice treated with control rat rat IgG1 (Nx-salt-rat IgG1). Correspondingly, cardiac fibrosis was significantly attenuated in Nx-salt-MR16-1 mice compared with Nx-salt-rat IgG1 mice. Furthermore, in the heart of Nx-salt-MR16-1 mice, expression of mRNA for nicotinamide adenine dinucleotide phosphate oxidase-2, an oxidative stress marker, was significantly downregulated compared with Nx-salt-rat IgG1 mice. Increases in cardiac metabolites, including histidine and γ-butyrobetaine, were also reversed by IL-6 blockade treatment. In conclusion, IL-6 blockade exerts anti-inflammatory, antifibrotic, and partial antioxidative effects in the heart of Nx-salt mice.NEW & NOTEWORTHY In the present study, IL-6 blockade exerted anti-inflammatory, antifibrotic, and partial antioxidative effects on the hearts of mice with CKD on a high-salt diet. Therefore, IL-6 potentially mediates cardiac fibrosis induced by high salt intake in patients with CKD, a finding with therapeutic implications. Of note, the next therapeutic implication may simply be the reinforcement of low-salt diets or diuretics and further research on the anti-inflammatory effects of these measures rather than IL-6 blockade with high-salt diet.

Kinetics of carnitine concentration after switching from oral administration to intravenous injection in hemodialysis patients.

Carnitine has high dialyzability and is often deficient in dialysis patients. This deficiency is treated by either intravenous (IV) or oral supplementation of carnitine. In this study, the mode of carnitine administration was changed from oral to IV in 17 hemodialysis (HD) patients, and the treatment was discontinued after 1 year. We found that the levels of total carnitine (TC), free-carnitine (FC), and acyl-carnitine (AC) significantly increased after 3 months of switching to IV administration (p < .05). After discontinuation of carnitine administration, the TC, FC, and AC levels decreased before dialysis. The average FC value was maintained at the normal levels until 9 months, but fell below the normal values when measured at the 12th month of discontinuation. In conclusion, carnitine was maintained at significantly high levels despite the smaller dose by IV infusion as compared with that by oral administration. We therefore suggest that our results be considered while determining both the carnitine administration route and the administration period in dialysis patients under clinical settings.

High urinary albumin/creatinine ratio at admission predicts poor functional outcome in patients with acute ischaemic stroke.

AIM: Albuminuria and a low estimated glomerular filtration rate (eGFR) are widely recognized indices of kidney dysfunction and have been linked to cardiovascular events, including stroke. We evaluated albuminuria, measured using the urinary albumin/creatinine ratio (UACR), and the eGFR in the acute phase of ischaemic stroke, and investigated the clinical characteristics of ischaemic stroke patients with and those without kidney dysfunction. METHODS: The study included 422 consecutive patients admitted between June 2010 and May 2012. General blood and urine examinations were performed at admission. Kidney dysfunction was defined as a low eGFR (<60 mL/min per 1.73 m2 ), high albuminuria (≥30 mg/g creatinine), or both. Neurological severity was evaluated using the National Institutes of Health Stroke Scale (NIHSS) at admission and the modified Rankin scale (mRS) at discharge. A poor outcome was defined as a mRS score of 3-5 or death. The impacts of the eGFR and UACR on outcomes at discharge were evaluated using multiple logistic regression analysis. RESULTS: Kidney dysfunction was diagnosed in 278 of the 422 patients (65.9%). The eGFR was significantly lower and UACR was significantly higher in patients with a poor outcome than in those with a good outcome. In multivariate analyses performed after adjusting for confounding factors, UACR >31.2 mg/g creatinine (OR, 2.58; 95% CI, 1.52-4.43; P = 0.0005) was independently associated with a poor outcome, while a low eGFR was not associated. CONCLUSIONS: A high UACR at admission may predict a poor outcome at discharge in patients with acute ischaemic stroke.

Febuxostat for treating allopurinol-resistant hyperuricemia in patients with chronic kidney disease.

BACKGROUND: Availability of the novel xanthine oxidase inhibitor febuxostat, which has multiple excretion pathways, enables investigation of the significance of serum uric acid control on renal function in patients with chronic kidney disease (CKD). METHODS: This was an exploratory, retrospective, observational study conducted at a single Japanese center. Serum uric acid concentrations and serum creatinine levels in the 6 months before and after the start of febuxostat treatment were collected for CKD patients switched from allopurinol after failing to achieve serum uric acid concentrations ≤6.0 mg/dL. RESULTS: Evaluable data were available for 60 patients, 67% of whom had advanced CKD (eGFR <30 mL/min/1.73 m2). Mean dose of febuxostat was 15.9 (± 8) mg/day. Mean serum uric acid concentration decreased from 8.4 (±1.4) mg/dL at baseline to 6.2 (±1.2) mg/dL at 6 months; 47.5% of patients achieved a level ≤6.0 mg/dL. The change from baseline in eGFR was positive at all time points during febuxostat treatment and the increase of 2.3 (±5.6) mL/min/1.73 m2 at 6 months was significant (p = 0.0027). Whereas the eGFR slope was negative during allopurinol treatment, it became positive after the switch to febuxostat. The change in eGFR slope before and after febuxostat treatment was significant for all patients (p < 0.01), for male patients (p < 0.05), and for patients with a baseline eGFR of <15 mL/min/1.73 m2 (p < 0.05). CONCLUSIONS: In patients with CKD, febuxostat reduces serum uric acid concentrations effectively and may suppress the progressive decline in renal function.

Low Serum Albumin Levels are Associated with Short-Term Recurrence of Arteriovenous Fistula Failure.

BACKGROUND: Vascular access intervention therapy (VAIVT) is widely used as a treatment for arteriovenous fistula (AVF) failure. However, recurrent AVF failure is a major concern for dialysis patients. By prospectively observing patients after an initial VAIVT, we attempted to identify risk factors for developing restenosis of AVF. METHODS: This single-center prospective study evaluated 57 patients who underwent their first VAIVT procedure at our hospital from April 2022 through March 2023. We performed blood and biochemical tests during the first VAIVT to collect data on clinical variables. Ultrasonography was used to measure vessel diameter reduction rate, flow volume (FV) reduction rate, and increase in resistance index (RI) rate over a 3-month period. RESULTS: Within 3 months, 24 patients developed short-term shunt stenosis and 30 did not. Three were not traceable. In a comparison of the two groups, significant differences were observed in albumin (ALB), FV, RI, and elbow shunt. Analysis of change rates in the three ultrasound findings identified five factors (hematocrit, platelet count, activated partial thromboplastin time, ALB, and FV). The results of logistic regression models revealed that ALB was the most significant predictive factor for short-term shunt stenosis (p = 0.031). CONCLUSION: In conclusion, our findings suggest that low serum ALB at the time of initial VAIVT is a significant risk factor for short-term recurrence of AVF failure in hemodialysis patients. These findings emphasize the importance of careful routine monitoring to reduce the risk of AVF failure and associated complications.

Effect of Dotinurad on Serum Uric Acid Concentration in Chronic Kidney Disease Patients Treated with Febuxostat.

BACKGROUND: Febuxostat is recommended for treatment of severe hyperuricemia in chronic kidney disease (CKD). We previously reported a significant positive correlation between fractional excretion of uric acid (FEUA) and estimated excretion of uric acid (eEUA) in patients receiving febuxostat and proposed that the addition of uricosuric agents could further decrease serum uric acid (sUA) levels by enhancing FEUA and eEUA in patients treated with febuxostat. METHODS: This retrospective study included 34 patients with CKD who were categorized into three groups (G3-G5) according to their estimated glomerular filtration rate (eGFR). The effects on sUA, FEUA, and eEUA of adding dotinurad (0.5 mg/day) to febuxostat (10 mg/day) were evaluated in these patients. Specifically, we examined changes in sUA, FEUA, and eEUA in each group after the addition of dotinurad. RESULTS: Dotinurad significantly increased FEUA in all groups and notably decreased sUA in groups G3 and G4 but not in group G5. There was no significant change in eEUA in any group. Dotinurad maintained the significant positive correlation between FEUA and eEUA in patients receiving febuxostat. CONCLUSIONS: This study is the first to show the effect of combining dotinurad with febuxostat in lowering sUA levels in G3 and G4 patients. Additional research is required in order to clarify the pharmacological mechanisms of dotinurad in patients with CKD.

The efficacy and safety of ivabradine hydrochloride in hemodialysis patients with chronic heart failure.

INTRODUCTION: There is little evidence for ivabradine hydrochloride in patients undergoing hemodialysis. METHODS: In this open-label prospective interventional trial of hemodialysis patients with chronic heart failure, during 12 weeks of treatment, changes in Heart rate (HR), frequency of dialysis-related hypotension were examined, and we investigated health-related quality of life (HR-QOL) and adverse effects. RESULTS: 18 patients from 6 facilities were enrolled in the study. HR significantly decreased over time, from 87 ± 12.61/min at baseline to 75.85 ± 8.91/min (p = 0.0003), and systolic blood pressure also increased significantly (p < 0.0001). The frequency of dialysis-related hypotension was markedly reduced (p = 0.0001). The HR-QOL survey showed significant improvements in Social Functioning among others (p = 0.0178). No specific adverse events occurred. CONCLUSION: Ivabradine hydrochloride improved dialysis-related hypotension. Furthermore, the HR-QOL improvement effect were suggested. These results demonstrated the safety and effectiveness of ivabradine hydrochloride.

Changes in Treatment Conditions for Patients Receiving Hemodialysis at Nippon Medical School Hospital during the COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic has had an enormous impact on hemodialysis patients. This study investigated changes in hemodialysis treatment at our hospital after the start of the pandemic. METHODS: We analyzed data from the Diagnosis Procedure Combination (DPC) system. Data for inpatients receiving dialysis during collection periods A (before the COVID-19 pandemic) and B (after the start of the COVID-19 pandemic) were extracted and compared. The numbers of inpatients and new patients, the number of patients admitted (by department), duration of stay, mortality, place of residence, surgical procedures, and DPC classification were compared. RESULTS: There were no significant differences between periods in patient age, duration of hospital stay, number of new patients, number of ambulance transports, number of deaths, body mass index, comorbidities, laboratory variables before the first dialysis after hospitalization, or patient area of residence. Although differences were observed among the departments, the numbers of emergency dialysis inpatients and maintenance dialysis inpatients increased. The number of surgeries also increased overall, particularly for maintenance dialysis patients (p = 0.0273). The percentage of DPC III patients was significantly higher in period B (p = 0.0368). CONCLUSIONS: The number of surgeries performed on maintenance dialysis patients and the overall DPC III rate significantly increased after the start of the COVID-19 pandemic at our hospital, suggesting that COVID-19 worsened the condition of maintenance dialysis patients and prolonged hospital stays.

The effects of tolvaptan on patients with severe chronic kidney disease complicated by congestive heart failure.

BACKGROUND: Tolvaptan, a diuretic with a new mechanism of action, selectively binds to the vasopressin V2 receptor and inhibits reabsorption of water. Its effect on heart failure is proven, but its benefit for patients with chronic kidney disease (CKD) has not been not confirmed. In this study, we examined the effect of tolvaptan on patients with severe CKD. METHODS: We analyzed patients with stage 4 or higher CKD who had congestive heart failure that was resistant to existing diuretics. The patients were administered an initial tolvaptan dose of 7.5 mg/day. We assumed urine volume and urine osmolality to be the main effective endpoint and recorded free water clearance, serum osmolality, serum creatinine (Cr) level, and adverse events. RESULTS: There was no instance of clinically significant hypernatremia. The urine volume increased significantly (P < 0.0001), as did the urine osmolality (P = 0.0053). Free water clearance showed a tendency to increase, although the difference was not statistically significant. The serum creatinine level did not change significantly, and there was no clear effect on renal function. However, in patients with stage 5 CKD, the serum creatinine level decreased significantly (n = 5, P = 0.0435). There were no adverse events. CONCLUSION: We confirmed that tolvaptan has a diuretic effect in patients with both severe CKD and congestive heart failure without causing either clinically significant hypernatremia or an adverse effect on renal function. Tolvaptan is an effective diuretic for patients with CKD.

A possible role of classical complement pathway activation in the pathogenesis of immunoglobulin G nephropathy: a case report.

Immunoglobulin G (IgG) nephropathy refers to a rare group of diseases characterized by deposits of IgG in the mesangial region. However, IgG nephropathy is controversial as a single disease entity, and its pathogenesis remains to be elucidated. In the present report, we discuss a case of IgG nephropathy in which we observed activation of the classical complement pathway.A 47-year-old woman was admitted to our hospital with nephrotic syndrome. Light-microscopic examination revealed neither proliferative nor sclerotic lesions in the glomeruli. However, unusual and large deposits were observed in the paramesangial area. An immunofluorescence study revealed predominant IgG and C1q and slight C3 deposits in the paramesangial area, suggesting immune-complex-type glomerular disease. An electron microscopic study also revealed different sizes of non-organized electron-dense deposits with a similar pattern of distribution, which were accompanied by foot process effacement. Clinically, there was no evidence of systemic diseases, such as infectious or autoimmune diseases (including systemic lupus erythematosus). Based on these findings, she was diagnosed with IgG nephropathy and treated with prednisolone. Steroid therapy was effective, and complete remission was maintained.Additional immunological examination revealed that IgG deposits were polyclonal and consisted mainly of the IgG1 and IgG3 subclasses. Furthermore, staining was positive for C4d and C5b-9. The present findings indicate that the pathogenesis of IgG nephropathy in our patient may have involved activation of the classical complement pathway.

Efficacy of aliskiren in Japanese chronic kidney disease patients with hypertension.

BACKGROUND: Aliskiren, a novel direct renin inhibitor, is hypothesized to inhibit the renin-angiotensin- system. This study attempted to provide insight into this mechanism by examining the antihypertensive and renoprotective effects of aliskiren in hypertensive chronic kidney disease (CKD) patients. METHODS: After recruitment, 43 hypertensive CKD patients (mean age, 53.7 years) began treatment of aliskiren. The patients were classified into high (over 30 mL/min/1.73 m(2)) estimated glomerular filtration rate (eGFR) group or low (under 30 mL/min/1.73 m(2)) eGFR group for comparison of measurements of various parameters over the 6-month observation period. RESULTS: Systolic blood pressure/diastolic blood pressure of 150 mg/day group decreased to an average of 126.8 ± 21.6 mmHg/69.3 ± 15.1 mmHg (average decrease: -7.4/-8.3 mmHg) over the 6-month observation period, while that of 300 mg/day group significantly decreased to an average of 133.5 ± 14.0 mmHg/71.5 ± 11.7 mmHg (average decrease: -21.1/-14.6 mmHg). Urinary protein of all patients decreased slightly and insignificantly to 1.1 ± 1.7 g/gCr from 1.4 ± 2.5 g/gCr. The serum creatinine (Cr) level of all patients decreased from 1.81 ± 1.10 mg/dL to 1.78 ± 0.82 mg/dL. Although the serum Cr level of the high eGFR group decreased from 1.28 ± 0.45 mg/dL to 1.27 ± 0.57 mg/dL, that of the low eGFR group slightly but insignificantly increased from 2.49 ± 0.64 mg/dL to 2.69 ± 1.11 mg/dL. CONCLUSION: Administration of aliskiren exerts an antihypertensive effect on hypertensive CKD patients that may lead to a decrease in urinary protein and an improvement in renal functioning.

Effects of Renal Function on Urinary Excretion and Serum Concentration of Uric Acid in Patients Treated with Febuxostat for Chronic Kidney Disease.

BACKGROUND: Febuxostat is recommended for lowering serum uric acid (sUA) concentration in chronic kidney disease (CKD) patients with hyperuricemia. However, it remains uncertain how febuxostat affects associations between several laboratory variables related to glomerular filtration and renal tubular reabsorption of uric acid. METHODS: We retrospectively analyzed the records of 148 patients with CKD and hyperuricemia: 122 were treated with febuxostat, and 26 were not. Clinical and laboratory variables were used to calculate estimated glomerular filtration rate (eGFR), fractional excretion of uric acid (FEUA), and estimated 24-h urinary excretion of uric acid (eEUA). We examined correlations of those variables and compared patients who did and did not receive febuxostat. RESULTS: eGFR and FEUA were significantly inversely regardless of febuxostat-treatment status. eGFR was significantly inversely correlated with sUA in patients who received febuxostat, but not in those who did not. Similarly, there was a significant positive correlation between FEUA and eEUA only in patients treated with febuxostat. CONCLUSIONS: FEUA increased as eGFR decreased in our patients. Febuxostat changed correlation patterns for clinical and laboratory variables. Additional administration of uricosuric agents might help further lower sUA by increasing FEUA and eEUA in patients treated with febuxostat.

Risk Factors for Early Peritoneal Dialysis Discontinuation: Importance of Heart Failure.

BACKGROUND: The number of patients on peritoneal dialysis (PD) in our hospital has increased during the past 5 years, but the number discontinuing PD has also increased. The purpose of this study was to identify the risk factors for PD discontinuation by analyzing the association between technical survival period (defined as the duration of PD) and various clinical factors. METHODS: We retrospectively investigated 87 patients who were started on PD at our hospital and attended regularly from April 2015 to March 2020, and we analyzed the association between technical survival period and various clinical factors. We also looked for associations between technical survival period and hospitalizations for heart failure, peritonitis, and exit-site infections among patients undergoing PD. RESULTS: The patients using renin-angiotensin-aldosterone system inhibitors (RASi) (P = 0.0218), those with left ventricular ejection fraction (LVEF) > 50% (P = 0.0194) when they started PD, and those with estimated glomerular filtration rate (eGFR) ≥ 6 (mL/min/1.73 m2) (P = 0.0013) at the initiation of PD showed significantly longer technical survival period, and those who were hospitalized for heart failure had significantly shorter period (P = 0.0008). CONCLUSION: Treatment of RASi, LVEF > 50% and eGFR ≥ 6 mL/ min/1.73 m2 when the initiation of PD and better volume control to prevent ultrafiltration failure and heart failure may improve technical survival period in patients undergoing PD.

Imaging Findings in a Case of Bacteremia Caused by Non-Typhoidal Salmonella Associated with a Congenital Venous Malformation.

Non-typhoidal Salmonella infection is a typical food-poisoning disease, which rarely causes bacteremia, except in immunocompromised individuals. We report the case of a healthy adult in whom a varicose vein associated with a lower-leg venous malformation was considered the source of Salmonella bacteremia.

Anti-neutrophil Cytoplasmic Antibody-associated Vasculitis Superimposed on Post-streptococcal Acute Glomerulonephritis.

A 44-year-old woman was admitted due to gross hematuria and progressive renal dysfunction. Poststreptococcal acute glomerulonephritis (PSAGN) was suspected due to her elevated anti-streptolysin O and anti-streptokinase titers and hypocomplementemia. A renal biopsy showed crescent formation and endocapillary hypercellularity with neutrophil infiltrate. An immunofluorescence analysis showed granular immunoglobulin G and C3 deposition, suggesting immune-complex-type glomerulonephritis. However, myeloperoxidase anti-neutrophil cytoplasmic antibody (ANCA) was positive, and peritubular capillaritis was observed. Furthermore, citrullinated histone H3-positive neutrophils were detected as markers for neutrophil extracellular trap formation. Therefore, she was diagnosed with ANCA-associated vasculitis superimposed on PSAGN that was the main contributor to her progressive renal injury.

Long-Term Benefits of Treatment with Tolvaptan in Patients with Autosomal Dominant Polycystic Kidney Disease.

BACKGROUND: Tolvaptan is the first effective drug treatment for autosomal dominant polycystic kidney disease (ADPKD) patients, but few long-term observations of the effects of tolvaptan have been reported. METHODS: In this single center, retrospective cohort study, we investigated nine patients who participated in a phase 3 trial of tolvaptan for ADPKD patients at our hospital between 2008 and 2014. Six of the patients discontinued tolvaptan at the end of the clinical trial and were defined as the discontinuation group, and three continued to take it; these were defined as the continuation group. The observation period was 3 years before and after the end of the tolvaptan trial, and we compared the following data in each group: serum creatinine, estimated glomerular filtration rate (eGFR), total kidney volume, serum sodium concentration, and urine specific gravity. RESULTS: eGFR was significantly improved after the end of the trial in the continuation group (P = 0.0446), but there was no significant change in the regression line before and after the end of the trial in the discontinuation group. The increases in mean total kidney volume rates over the 3 years before and after the trial were 0.01%/year vs. 0.067%/year in the discontinuation group (P = 0.0247). On the other hand, serum sodium concentration and urine specific gravity showed no change during the observation period. CONCLUSION: This study suggested that long-term administration of tolvaptan may improve renal function and inhibit total kidney volume growth.