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Background: During peritoneal dialysis (PD), solute transport and ultrafiltration are mainly achieved by the peritoneal blood vasculature. Glycocalyx lies on the surface of endothelial cells and plays a role in vascular permeability. Low-glucose degradation product (GDP), pH-neutral PD solutions reportedly offer higher biocompatibility and lead to less peritoneal injury. However, the effects on the vasculature have not been clarified., Methods: Peritoneal tissues from 11 patients treated with conventional acidic solutions (acidic group) and 11 patients treated with low-GDP, pH-neutral solutions (neutral group) were examined. Control tissues were acquired from 5 healthy donors of kidney transplants (control group). CD31 and ratio of luminal diameter to vessel diameter (L/V ratio) were evaluated to identify endothelial cells and vasculopathy, respectively. Immunostaining for heparan sulfate (HS) domains and Ulex europaeus agglutinin-1 (UEA-1) binding was performed to assess sulfated glycosaminoglycans and the fucose-containing sugar chain of glycocalyx., Results: Compared with the acidic group, the neutral group showed higher CD31 positivity. L/V ratio was significantly higher in the neutral group, suggesting less progression of vasculopathy. Both HS expression and UEA-1 binding were higher in the neutral group, whereas HS expression was markedly more preserved than UEA-1 binding in the acidic group. In vessels with low L/V ratio, which were found only in the acidic group, HS expression and UEA-1 binding were diminished, suggesting a loss of glycocalyx., Conclusion: Peritoneal endothelial glycocalyx was more preserved in patients treated with low-GDP, pH-neutral solution. The use of low-GDP, pH-neutral solutions could help to protect peritoneal vascular structures and functions., (© 2021. Japanese Society of Nephrology.)

Background: The Moncrief-Popovich technique of peritoneal catheter implantation has beneficial effects for peritoneal dialysis (PD) initiation. However, it might increase the risk of peritoneal catheter obstruction by fibrin clots, because the catheter is buried under the skin for several weeks to months. Effects of treatment of intraluminal occlusion of PD catheters with tissue plasminogen activator, recommended by the International Society for Peritoneal Dialysis guidelines/recommendations are reportedly limited. We investigated the effectiveness of the 'alpha-replacer' (JMS, Tokyo, Japan) for PD catheter obstruction., Methods: We retrospectively analyzed a total of 193 patients in whom PD was initiated. PD catheters were embedded using the Moncrief-Popovich technique in 130 of these patients. We assessed the occurrence rates of peritoneal catheter obstruction and the utility of the alpha-replacer for treating intraluminal catheter occlusion by fibrin clots., Results: Catheter obstruction occurred in eight cases with embedded catheters, one due to omental wrapping and the others due to fibrin clots, in which median catheter burial durations were 477 (interquartile range [IQR], 226-510) days. All catheter obstructions due to fibrin clots were successfully treated with the alpha-replacer, leading to improved catheter drainage. The median amount of contrast agent used in catheterography was 10 (IQR 9-10) mL, which did not adversely affect residual renal function. There were no complications. No recurrence occurred during the observation period (median 111, IQR 55.5-141 months)., Conclusion: Our results suggest that treatment with the alpha-replacer is a safe and effective treatment option for intraluminal obstruction of PD catheters by fibrin clots.

Background: Hypernatremia is a major electrolyte disorder associated with death among critically ill patients. Glucocorticoid therapy may cause hypernatremia in refractory septic shock patients, but the association between glucocorticoid and intensive care unit (ICU)-acquired hypernatremia (IAH) remains unclear. The aim of this study was to clarify whether glucocorticoid administration was associated with IAH., Methods: This was a nested case-control study using data from an established cohort including 121 IAH cases identified from 1756 patients who were admitted to ICU in a tertiary care facility in Japan. We included patients who were admitted with a normal range of serum sodium concentrations (130-149 mEq/L) from January 1, 2013 to December 31, 2015 and remained in ICU for ≥ 2 days. Hypernatremia was defined as serum sodium concentration ≥ 150 mEq/L. Each case was matched to one control., Results: Multivariable conditional logistic regression revealed high-dose glucocorticoid {odds ratio (OR), 4.15 [95% confidence interval (CI) 1.29-13.4]}, acute kidney injury (AKI) [OR, 2.72 (95% CI 1.31-5.62)], and osmotic diuretics [OR, 3.44 (95% CI 1.41-8.39)] to be significantly associated with IAH. The contents and amounts of fluid infusion were not significantly associated with IAH. There were also significant duration-response effects between duration of glucocorticoid use and IAH; however, pulse glucocorticoid administration was not associated with IAH., Conclusion: In this nested case-control study, we demonstrated a significant association between IAH and high-dose glucocorticoid with significant duration-response effects. Serum sodium concentrations should be monitored carefully in critically ill patients administered prolonged high-dose glucocorticoid.

Background: There have been only a few large-scale cohort studies that have reviewed accumulated cases of thrombotic microangiopathy (TMA). The aim of this study was to collect and analyze TMA cases based on the renal biopsy, as a nationwide survey in Japan., Methods: In this cross-sectional study, large nationwide data from the Japan Renal Biopsy Registry (J-RBR) were used. Among the patients registered in the J-RBR online system from July 2007 to July 2017, TMA cases were extracted and epidemiological data and clinical findings were investigated., Results: Out of the 38,495 patients enrolled in a period of 10 years, 152 (0.39%) cases had been diagnosed with TMA. The patient age was widely distributed, including 9.2%, 66.4%, and 24.3% for children, adults, and the elderly, respectively. There were various causes of TMA. Among them, hemolytic uremic syndrome (HUS)/thrombotic thrombocytopenic purpura (TTP) (16.4%), connective tissue disease (CTD)-related (17.1%), and drug-induced (16.4%) were frequently observed. The background factors of TMA were different in children and adults. In a comparison between groups consisting of HUS/TTP, CTD-related, and drug-induced, the HUS/TTP group was significantly younger (p = 0.01), and the drug-induced TMA group tended to have a high urinary protein positive rate (p = 0.05). A comparative analysis according to the age group showed significantly higher serum creatinine levels in the elderly (p < 0.01)., Conclusion: This is the first report of epidemiological and clinical data of biopsy-proven TMA in Japan. The characteristics of TMA with diversity based on the underlying disease and age group were reported.

In the original publication, some errors have been found in the alignment of Table 9. The corrected table is given below.

Background: Practice patterns and bleeding complications of percutaneous native kidney biopsy (PNKB) have not recently been investigated and the Japanese Society of Nephrology performed a nationwide questionnaire survey in 2018., Methods: The survey consisted of nine sections about PNKB: (1) general indications; (2) indications for high-risk patients; (3) informed consent; (4) pre-biopsy evaluation; (5) procedures; (6) sedation; (7) post-biopsy hemostasis, bed rest, and examinations; (8) bleeding complications; and (9) specimen processing. A supplementary survey examined bleeding requiring transcatheter arterial embolization (TAE)., Results: Overall, 220 directors of facilities (nephrology facility [NF], 168; pediatric nephrology facility [PF], 52) completed the survey. Indications, procedures, and monitoring protocols varied across facilities. Median lengths of hospital stay were 5 days in NFs and 6 days in PFs. Gauge 14, 16, 18 needles were used in 5%, 56%, 33% in NFs and 0%, 63%, 64% in PFs. Mean limits of needle passes were 5 in NFs and 4 in PFs. The bed rest period was 16-24 h in 60% of NFs and 65% of PFs. Based on 17,342 PNKBs, incidence rates of macroscopic hematuria, erythrocyte transfusion, and TAE were 3.1% (NF, 2.8%; PF, 6.2%), 0.7% (NF, 0.8%; PF, 0%), and 0.2% (NF, 0.2%; PF, 0.06%), respectively. Forty-six percent of facilities processed specimens all for light microscopy, immunofluorescence, and electron microscopy, and 21% processed for light microscopy only. Timing of bleeding requiring TAE varied among PNKB cases., Conclusion: Wide variations in practice patterns of PNKB existed among facilities, while PNKBs were performed as safely as previously reported.

Background: The morphological changes induced by bio-incompatible peritoneal dialysis (PD) solutions are well known. However, the morphological damage induced by long-term low-glucose degradation product (GDP), pH-neutral solutions has not been reported in detail. The aim of this study was to investigate the long-term effects of pH-neutral PD solutions on morphological and functional changes in the peritoneal membrane., Methods: We assessed peritoneal membrane biopsy samples from PD patients treated with acidic (Conventional group) or pH-neutral solutions (pH-neutral group) using pathology and immunopathology techniques., Results: Analyses of 54 Conventional and 73 pH-neutral group samples showed that the peritoneal membrane was thicker (P < 0.001), the ratio of luminal diameter to vessel diameter (L/V ratio) was significantly smaller (P < 0.001), and advanced glycation end-product (AGE) accumulation was higher in the Conventional than in the pH-neutral group (P < 0.001). Comparison of samples from patients in the Conventional (n = 33) and pH-neutral groups (n = 33) who were treated for 4-10 years also showed significant differences in peritoneal thickness, L/V ratio and AGE score. Furthermore, the L/V ratio in the Conventional group significantly decreased over time (P < 0.01); however, no such change was seen in the pH-neutral group. Peritoneal membrane thickness was not associated with PD duration in both groups. Dialysate-to-plasma ratio of creatinine and L/V ratio negatively correlated with PD treatment duration in the Conventional group, but not in the pH-neutral group., Conclusions: These findings suggest that pH-neutral solutions prevent the morphological and functional peritoneal changes induced by long-term PD treatment.

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.

Background: Ultrafiltration failure associated with peritoneal membrane dysfunction is one of the main complications for patients on long-term peritoneal dialysis (PD). The dialysate-to-plasma concentration ratio (D/P) of creatinine is widely used to assess peritoneal membrane function. However, other small-sized solutes have not been studied in detail as potential indicators of peritoneal permeability., Methods: We studied the D/Ps of small, middle-sized and large molecules in peritoneal equilibration tests in 50 PD patients. We applied metabolomic analysis of comprehensive small molecular metabolites using capillary electrophoresis time-of-flight mass spectrometry., Results: D/Ps of middle-sized and large molecules correlated positively with D/P creatinine. Most D/Ps of small molecules correlated positively with D/P creatinine. Among 38 small molecules contained in the dialysate, urea, citrulline and choline showed significantly lower ability to permeate than creatinine. In the relationship between D/Ps of creatinine and small molecules, regression coefficients of three molecules were less than 0.3, representing no correlation to D/P creatinine. Five molecules showed negative regression coefficients. Among these molecules, hippurate and 3-indoxyl sulfate showed relatively high teinpro binding rates, which may affect permeability. Serum concentrations of two molecules were higher in the Low Kt/V group, mainly due to high protein binding rates., Conclusions: D/Ps of some molecules did not correlate with D/P creatinine. Factors other than molecular weight, such as charge and protein binding rate, are involved in peritoneal transport rates. Metabolomic analysis appears useful to analyze small molecular uremic toxins, which could accumulate in PD patients, and the status of peritoneal membrane transport for each molecule.

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.

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.

Background: The Oxford Classification is utilized globally, but has not been fully validated. In this study, we conducted a comparative analysis between the Oxford Classification and Japanese Histologic Classification (JHC) to predict renal outcome in Japanese patients with IgA nephropathy (IgAN)., Methods: A retrospective cohort study including 86 adult IgAN patients was conducted. The Oxford Classification and the JHC were evaluated by 7 independent specialists. The JHC, MEST score in the Oxford Classification, and crescents were analyzed in association with renal outcome, defined as a 50% increase in serum creatinine., Results: In multivariate analysis without the JHC, only the T score was significantly associated with renal outcome. While, a significant association was revealed only in the JHC on multivariate analysis with JHC., Conclusions: The JHC and T score in the Oxford Classification were associated with renal outcome among Japanese patients with IgAN. Superiority of the JHC as a predictive index should be validated with larger study population and cohort studies in different ethnicities.

Background: Previous studies have suggested that high neutrophil/lymphocyte ratios are related to worse outcome in patients with cardiovascular diseases. Patients with end-stage renal disease, especially those with inflammation, are at an increased risk of premature mortality, primarily because of cardiovascular disease. We aimed to clarify if high neutrophil/lymphocyte ratio is associated with increasing cardiovascular events in Japanese patients with end-stage renal disease., Methods: We enrolled 86 incident Japanese dialysis patients (58 men, age 58 ± 11 years) in a prospective cohort study. The median follow-up was for 38.7 months. The association between neutrophil/lymphocyte ratio at the start of dialysis therapy and clinical biomarkers was investigated. Relative risks and cumulative cardiovascular disease events were calculated., Results: The median neutrophil/lymphocyte ratio reported was 3.72. The duration from the start of the dialysis therapy to the first cardiovascular disease event was significantly shorter as a neutrophil/lymphocyte ratio increased (log-rank test, P = 0.003). The relative risk of cardiovascular disease events in patients with neutrophil/lymphocyte ratio > median to cardiovascular events in patients with the ratio < median as a reference was 3.02 (95 % CI 1.32-8.00) in a Cox proportional hazard model. The cumulative cardiovascular disease events during the observational period was higher in patients with neutrophil/lymphocyte ratio > median (23.0 events 100 person-years) than in patients with the ratio < median (6.8 events 100 person-years)., Conclusions: A higher neutrophil/lymphocyte ratio is associated with increased risk of cardiovascular disease events and is a stronger predictor of future events.

Incretin-based therapy was first made available for the treatment of type 2 diabetes mellitus (T2DM) in the US in 2006 and in Japan in 2009. Four DPP-4 inhibitors and two GLP-1 analog/receptor agonists are currently available. The effects of incretin-based therapy are assumed to be exerted mainly through the hormonal and neuronal actions of one of the incretins, GLP-1, which is secreted from L cells localized in the small intestine. The benefits of this therapy over conventional sulfonylureas or insulin injections, such as fewer hypoglycemic events and reduced body weight gain, derive from the glucose-dependent insulinotropic effect. The protective effects of this therapy on vulnerable pancreatic β-cells and against micro/macroangiopathy in T2DM are also most welcome. Indications and/or contraindications for incretin-based therapy should be clarified by prospectively studying the experiences of Japanese T2DM patients undergoing this therapy in the clinical setting.