Association of serum sodium levels with fractures and mortality in patients undergoing maintenance hemodialysis.

BACKGROUND: Hyponatremia is implicated in pathological bone resorption and has been identified as a risk factor for bone fracture in the general population. However, there are limited data on the association between serum sodium levels and fracture risk in patients undergoing hemodialysis (HD). METHODS: We analyzed a historical cohort of 2220 maintenance HD patients to examine the association between serum sodium levels and the risk of fracture and mortality. We also examined the association between serum sodium levels and osteoporosis, based on metacarpal bone mineral density, in a subcohort of 455 patients with available data. In addition, we examined the association between serum sodium levels and bone turnover markers in a separate cross-sectional cohort of 654 maintenance HD patients. RESULTS: During a median follow-up of 5.4 years, 712 patients died, 113 experienced clinical fractures, and 64 experienced asymptomatic vertebral fractures. Lower serum sodium levels were associated with an increased risk of mortality (HR 1.06 per 1 mEq/L decrease; 95% CI 1.03-1.09) but not with the risk of clinical fracture (HR 1.04 per 1 mEq/L decrease; 95% CI 0.97-1.11). A similar lack of association was observed for asymptomatic vertebral fracture and any fracture. Serum sodium levels were also not associated with osteoporosis in a subcohort with available data (n = 455) or with bone alkaline phosphatase or tartrate-resistant acid phosphatase-5b in a separate cross-sectional cohort. CONCLUSION: Serum sodium levels were associated with mortality but not with fracture risk, osteoporosis, or bone turnover markers in maintenance HD patients.

De novo posttransplant membranous nephropathy after COVID-19 vaccination 9 years after renal transplantation in a patient with polycystic kidney disease.

A 63-year-old man with polycystic kidney disease underwent kidney transplantation from his wife. Nine years later, after the first and second doses of the COVID-19 vaccination, he developed proteinuria, hematuria, and elevated C-reactive protein. Kidney biopsy 7 months after the initial appearance of proteinuria showed immunoglobulin (Ig)-G granular stain, predominantly IgG1, and spike formation in the glomerular basement membrane. Electron microscopy revealed mainly subepithelial deposits, which corresponds to membranous nephropathy (MN) stage 3 of the Ehrenreich-Churg classification indicating chronic disease, but it also showed electron-dense deposits and endothelial damage. Because a kidney biopsy was performed 1 h after renal transplantation and a biopsy of the patient's native kidney showed intact glomeruli, atypical de novo posttransplant membranous nephropathy (MN) was diagnosed, and a close relationship with COVID-19 vaccination was assumed. Clinicians should consider the involvement of COVID-19 vaccination in de novo posttransplant MN with unclear pathogenesis.

Japanese clinical practice patterns of rituximab treatment for minimal change disease in adults 2021: A web-based questionnaire survey of certified nephrologists.

BACKGROUND: In Japan, rituximab (RTX) for adult-onset frequently relapsing (FR)/steroid-dependent (SD) minimal change disease (MCD) is not explicitly reimbursed by insurance, and its standard regimen has not been established. METHODS: We conducted a cross-sectional web-based survey between November and December 2021. The participants were nephrologists certified by the Japanese Society of Nephrology and answered 7 items about RTX for adult MCD. Factors related to the experience of RTX administration at their facilities were estimated by generalized estimating equations. RESULTS: Of 380 respondents, 181 (47.6%) reported the experience of RTX use for adult MCD at their current facilities. Those who worked at university hospitals (vs. non-university hospitals, proportion difference 13.7%) and at facilities with frequent kidney biopsies (vs. 0 cases/year, 19.2% for 1-40 cases/year; 37.9% for 41-80 cases/year; 51.9% for ≥ 81 cases/year) used RTX more frequently. Of 181 respondents, 28 (15.5%) answered that there was no insurance coverage for RTX treatment. Of 327 respondents who had the opportunity to treat MCD, which was a possible indication for RTX, 178 (54.4%) indicated withholding of RTX administration. The most common reason was the cost due to lack of insurance coverage (141, 79.2%). Regarding RTX regimens for FR/SD MCD, introduction treatment with a single body surface area-based dose of 375 mg/m2 and maintenance treatment with a 6-month interval were the most common. CONCLUSION: This survey revealed the nephrologists' characteristics associated with RTX use, the barriers to RTX use, and the variation in the regimens for adult MCD in Japan.

Preference for anti-phospholipase A2 receptor antibody assay in patients with suspected membranous nephropathy: a survey study on medical practice after publication of Japanese Guidelines for Nephrotic Syndrome 2020.

BACKGROUND: International practice guidelines advocate for the use of anti-phospholipase A2 receptor (PLA2R) antibody testing to diagnose primary membranous nephropathy (pMN). This study aimed to clarify the current status of anti-PLA2R antibody testing in the diagnosis of pMN in Japan and to scrutinize the factors associated with the implementation of this antibody test. METHODS: Utilizing a web-based questionnaire for nephrologists, responses were collected from 306 facilities and 427 nephrologists between November 2021 and December 2021. Preference for anti-PLA2R antibody testing was also investigated. Factors related to the experience of quantifying anti-PLA2R antibodies were estimated by generalized estimating equations using a robust analysis of variance with clusters of facilities of affiliation. RESULTS: Of the 427 respondents, 140 (32.8%) had previous measurement experience at their current workplace and 165 (38.6%) had previous measurement experience overall. In pMN-suspected cases without contraindications to renal biopsy, 147 (34.4%) of the respondents opted to request anti-PLA2R antibody testing. The respondents' experience with anti-PLA2R antibody quantification at their current place of work was generally higher in university hospitals and increased with the annual number of kidney biopsies and the number of years since graduation. CONCLUSION: The results of this study suggest that a significant proportion of nephrologists in Japan have no experience in performing anti-PLA2R antibody assays, and that the assays may be hampered by the limited capabilities of the current workplace and the financial burden on facilities and patients.

Practice patterns of rituximab for primary membranous nephropathy 2021 in Japan: a web-based survey of board-certified nephrologists.

BACKGROUND: Although rituximab (RTX) is recommended by kidney disease improving global outcomes as one of the standard therapies for primary membranous nephropathy (pMN), given the constraint of insurance coverage, it is not clear how the drug is used in Japan. METHODS: This cross-sectional study was conducted via a web-based survey between November and December 2021. The participants were certified nephrologists and recruited through convenience sampling. Experience with RTX for pMN was compared to experience with RTX for minimal change nephrotic syndrome (MCNS). Reasons for withholding RTX for pMN, even when it is indicated, were also investigated. Furthermore, the proportion difference in RTX experience was analyzed. RESULTS: Responses from 380 nephrologists across 278 facilities were analyzed. RTX was used for pMN by 83 (21.8%), which was less than the 181 (47.6%) who had used RTX for MCNS (ratio of proportions: 0.46). RTX use for pMN was more frequent in facilities performing 41-80 and 81 or more kidney biopsies annually (vs. none) and by physicians with experience in anti-PLA2R antibody measurement. RTX administration for pMN was covered by insurance for 56 (67.5%), was facility-paid for 10 (12.0%), and was copaid by patients for 6 (7.2%). The most common reason for withholding RTX for pMN was difficulty in ensuring financing (146, 79.3%). CONCLUSIONS: RTX use for pMN is less common than for MCNS but not infrequent. Treatment with RTX was more frequent in biopsy-intensive facilities, and it was fully paid by the facility or patient in one-fifth of cases.

Dynamic and static control of the off-target interactions of antisense oligonucleotides using toehold chemistry.

Off-target interactions between antisense oligonucleotides (ASOs) with state-of-the-art modifications and biological components still pose clinical safety liabilities. To mitigate a broad spectrum of off-target interactions and enhance the safety profile of ASO drugs, we here devise a nanoarchitecture named BRace On a THERapeutic aSo (BROTHERS or BRO), which is composed of a standard gapmer ASO paired with a partially complementary peptide nucleic acid (PNA) strand. We show that these non-canonical ASO/PNA hybrids have reduced non-specific protein-binding capacity. The optimization of the structural and thermodynamic characteristics of this duplex system enables the operation of an in vivo toehold-mediated strand displacement (TMSD) reaction, effectively reducing hybridization with RNA off-targets. The optimized BROs dramatically mitigate hepatotoxicity while maintaining the on-target knockdown activity of their parent ASOs in vivo. This technique not only introduces a BRO class of drugs that could have a transformative impact on the extrahepatic delivery of ASOs, but can also help uncover the toxicity mechanism of ASOs.

A Case of Glomerular Microangiopathy-like Nephropathy Caused by Hyperthyroidism.

A 49-year-old Japanese woman was admitted to our hospital with weight loss of 15 kg, nephrotic-range proteinuria (4.5 g/g.Cre), and hematuria over a 6-month period. She had received two doses of the COVID-19 vaccine one year before the onset of the disease, after which the estimated glomerular filtration rate increased. Laboratory tests and other tests led to a diagnosis of hyperthyroidism, and a kidney biopsy showed thrombotic microangiopathy-like glomerular microangiopathy comprising mainly glomerular endothelial cell damage. Thiamazole (30 mg) was started for the hyperthyroidism. Three months later, the thyroid function normalized, and two months later, the proteinuria and hematuria disappeared, suggesting that COVID-19 vaccination and these events were related.

Syphilis-related Membranous Nephropathy in a 35-year-old Woman.

A 35-year-old woman was admitted for the examination of lower leg edema and proteinuria. A kidney biopsy showed membranous nephropathy (MN) with fine granular deposits of IgG along the glomerular capillary and poor spike formation, differing from primary MN in the presence of positive IgG3 and C1q. Lupus nephritis was excluded because serum complement and anti-dsDNA antibody, anti-Smith antibody, and anti-cardiolipin antibody tests were negative. The serological test for syphilis was positive, as was the Treponema pallidum hemagglutination test. The patient was diagnosed with syphilis, and the proteinuria disappeared with antibiotic treatment. In MN with positive IgG3 and C1q, syphilis nephropathy may be a differential diagnosis.

Demographics and treatment of patients with primary nephrotic syndrome in Japan using a national registry of clinical personal records.

The nationwide clinical features of Japanese patients with primary nephrotic syndrome (NS), including minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), or membranous nephropathy (MN), have not yet been reported. We collected the clinical personal records of patients with primary NS between 2015 and 2018 from the national registry organized by the Japanese Ministry of Health, Labour, and Welfare. Overall, the demographics, chronic kidney disease classification based on glomerular filtration rate and albuminuria, and treatment of 6036 patients were collected: 3394 (56.2%) with MCD, 677 (11.2%) with FSGS, 1455 (24.1%) with MN, and 510 (8.5%) with others. MN patients were older than MCD and FSGS patients (67 vs. 42 and 47 years, respectively). Steroid-dependent NS or frequently relapsing NS was found in 70.2%, 40.5%, and 24.6%, whereas steroid-resistant NS was found in 6.4%, 36.0%, and 37.9% of patients in the MCD, FSGS, and MN, respectively. The present oral prednisolone use (mean dose, mg/day) was 87.2% (21.2), 80.9% (20.0), and 77.5% (18.8) of patients in the MCD, FSGS, and MN, respectively. The national registry of clinical personal records of primary NS could provide an informative insight into the characteristics, clinical features, and treatment approaches for patients with primary NS in Japan.

Water-Dispersible Carbon Nano-Test Tubes as a Container for Concentrated DNA Molecules.

Invited for the cover of this issue are Takashi Kyotani, Tetsuji Itoh and co-workers at Tohoku University, Gunma University and AIST. The image depicts the synthesis of water-dispersible carbon nano-test tubes by using a template technique and the selective adsorption of DNA into the inner space of these test tubes. Read the full text of the article at 10.1002/chem.202301422.

Water-Dispersible Carbon Nano-Test Tubes as a Container for Concentrated DNA Molecules.

Water-dispersible carbon nano-test tubes (CNTTs) with an inner and outer diameter of about 25 and 35 nm, respectively, were prepared by the template technique and then their inner carbon surface was selectively oxidized to introduce carboxy groups. The adsorption behavior of DNA molecules on the oxidized CNTTs (Ox-CNTTs) was examined in the presence of Ca2+ cations. Many DNA molecules are attracted to the inner space of Ox-CNTTs based on the Ca2+ -mediated electrostatic interaction between DNA phosphate groups and carboxylate anions on the inner carbon surface. Moreover, the total net charge of the DNA adsorbed was found to be equal to the total charge of the carboxylate anions. This selective adsorption into the interior of Ox-CNTTs can be explained from the fact that the electrostatic interaction onto the inner concave surface is much stronger than that on the outer convex surface. On the other hand, the desorption of DNA easily occurs whenever Ca2+ cations are removed by washing with deionized water. Thus, each of Ox-CNTTs works well as a nano-container for a large amount of DNA molecules, thereby resulting in the occurrence of DNA enrichment in the nanospace.

Sequential chiral induction between organic and inorganic supramolecular helical assemblies for the in situ formation of chiral carbon dots.

Self-organised helical bilayers of dicationic gemini surfactants confined in helical silica nanospace were transformed in situ to carbon dots (CDots) via pyrolysis. These water-dispersible CDots exhibit electronic absorption spanning the UV and visible range and possess symmetrical circular dichroism (CD) signals, the sign of which depends on the handedness of the helices.

Terahertz bandpass filter with Babinet complementary metamaterial mirrors and silicon subwavelength structure.

We fabricated a rigid bandpass filter with a broad far-infrared wavelength range of high transmission using a silicon subwavelength structure with a Babinet complementary metamaterial half-mirror pair, despite its apparent light-blocking structure. The rigid one-piece filter was produced by a simple process involving photolithography, dry etching, and deposition, each performed only once. The transmission principle relies on the Fabry-Perot resonance with a metamaterial half-mirror pair that exhibits extraordinary optical transmission due to spoof surface plasmon polaritons. The transmission center wavelength was successfully predicted by the basic equation of Fabry-Perot resonance with an effective medium approximation. In contrast, a narrower bandwidth and a lower minimum transmittance than those predicted from the basic equation were provided by the subwavelength Si structure between the metamaterial mirrors, resulting in enhanced bandpass filter characteristics.

Japanese clinical practice patterns of primary nephrotic syndrome 2021: a web-based questionnaire survey of certified nephrologists.

BACKGROUND: With the publication of the "Evidence-Based Clinical Practice Guideline for Nephrotic Syndrome 2020," we examined nephrologists' adherence to the recommendations of four of its clinical questions (CQs). METHODS: This was a cross-sectional web-based survey conducted between November and December 2021. The target population comprised nephrologists certified by the Japanese Society of Nephrology who were recruited using convenience sampling. The participants answered six items regarding the four CQs about adult patients with nephrotic syndrome and their characteristics. RESULTS: In total, 434 respondents worked in at least 306 facilities, of whom 386 (88.9%) provided outpatient care for primary nephrotic syndrome. Of these patients, 179 (41.2%) answered that they would not measure anti- phospholipase A2 receptor antibody levels in cases of suspected primary membranous nephropathy (MN) in which kidney biopsy was not possible (CQ1). Regarding immunosuppressants as maintenance therapy after relapse of minimal change nephrotic syndrome (CQ2), cyclosporine was the most common choice (290 [72.5%] and 300 [75.0%] of 400 respondents after the first and second relapses, respectively). The most common treatment for steroid-resistant cases of primary focal segmental glomerulosclerosis (CQ3) was cyclosporine (323 of 387, 83.5%). For the initial treatment of primary MN with nephrotic-range proteinuria (CQ4), corticosteroid monotherapy was the most common choice (240 of 403, 59.6%), followed by corticosteroid and cyclosporine (114, 28.3%). CONCLUSION: Gaps in recommendations and practices regarding serodiagnosis and treatment of MN (i.e., CQ1 and 4) are observed, suggesting the need to address the barriers to their insurance reimbursement and the lack of evidence behind them.

Unique Crosslinking Properties of Psoralen-Conjugated Oligonucleotides Developed by Novel Psoralen N-Hydroxysuccinimide Esters.

Psoralens and their derivatives, such as trioxsalen, have unique crosslinking features to DNA. However, psoralen monomers do not have sequence-specific crosslinking ability with the target DNA. With the development of psoralen-conjugated oligonucleotides (Ps-Oligos), sequence-specific crosslinking with target DNA has become achievable, thereby expanding the application of psoralen-conjugated molecules in gene transcription inhibition, gene knockout, and targeted recombination by genome editing. In this study, we developed two novel psoralen N-hydroxysuccinimide (NHS) esters that allow the introduction of psoralens into any amino-modified oligonucleotides. Quantitative evaluation of the photo-crosslinking efficiencies of the Ps-Oligos to target single-stranded DNAs revealed that the crosslinking selectivity to 5-mC is the unique feature of trioxsalen. We found that the introduction of an oligonucleotide via a linker at the C-5 position of psoralen can promote favorable crosslinking to target double-stranded DNA. We believe our findings are essential information for the development of Ps-Oligos as novel gene regulation tools.

Evaluation of ABCG2-mediated extra-renal urate excretion in hemodialysis patients.

Two-thirds of urate is excreted via the renal pathway and the remaining one-third via the extra-renal pathway, the latter mainly via the intestine in healthy individuals. ABCG2, a urate exporter, is expressed in various tissues including the kidney and intestine, and its dysfunction leads to hyperuricemia and gout. ABCG2 is regarded as being responsible for most of the extra-renal urate excretion. However, the extra-renal urate excretion capacity via ABCG2 remains undefined in end-stage kidney diseases. Therefore, we evaluated the capacity of extra-renal ABCG2 using 123 anuric hemodialysis patients whose urate excretion depended on only the extra-renal pathway. ABCG2 function in each participant was estimated based on ABCG2 dysfunctional variants. We computed the uric acid pool (PoolUA) from bodyweight and serum urate level (SUA) using previously reported radio-isotopic data, and we analyzed the association between ABCG2 function and the PoolUA. SUA and PoolUA increased significantly with ABCG2 dysfunction, and extra-renal ABCG2 could excrete up to approximately 60% of the daily uric acid turnover in hemodialysis patients. Our findings indicate that the extra-renal urate excretion capacity can expand with renal function decline and highlight that the extra-renal pathway is particularly important in the uric acid homeostasis for patients with renal dysfunction.

Enhanced podocyte differentiation and changing drug toxicity sensitivity through pressure-controlled mechanical filtration stress on a glomerulus-on-a-chip.

Podocytes, localized in the glomerulus, are a prognostic factor of proteinuria in kidney disease and are exposed to distinct physiological stimuli from basal to apical filtration flow. Research studies on drug discovery and disease modeling for glomerulopathy have developed a glomerulus-on-a-chip and studied podocyte mechanobiology to realize alternative methods to animal experiments. However, the effect of filtration stimulus on podocytes has remained unclear. Herein, we report the successful development of a user-friendly filtration culture device and system that can precisely control the filtration flow using air pressure control by incorporating a commercially available culture insert. It allows mouse podocytes to be cultured under filtration conditions for three days with a guarantee of maintaining the integrity of the podocyte layer. Using our system, this study demonstrated that podocyte damage caused by hyperfiltration resulting from glomerular hypertension, a common pathophysiology of many glomerulopathies, was successfully recapitulated and that filtration stimulus promotes the maturation of podocytes in terms of their morphology and gene expression. Furthermore, we demonstrated that filtration stimulus induced different drug responsiveness in podocytes than those seen under static conditions, and that the difference in drug responsiveness was dependent on the pharmacological mechanism. Overall, this study has revealed differentiating and pharmacodynamic properties of filtration stimulus and brings new insights into the research field of podocyte mechanobiology towards the realization of glomerulus-on-a-chip.

Serum Sclerostin Levels and Mortality in Hemodialysis Patients: An 8-Year Prospective Study.

INTRODUCTION: Sclerostin is an osteocyte-derived inhibitor of bone formation and is increased in kidney failure. Sclerostin might be involved in the pathogenesis of vascular calcification, but few studies have examined the association between sclerostin and mortality in hemodialysis patients. METHODS: We analyzed a prospective cohort of 654 patients undergoing maintenance hemodialysis. The primary exposure variable was the baseline serum sclerostin level measured at study enrollment. The primary outcome was 8-year all-cause mortality. Mortality risk was assessed using Cox regression models adjusted for potential confounders. RESULTS: During a median follow-up of 7.6 years (interquartile range, 4.1-8.0 years), 229 of the 654 participants died. In a univariate analysis, serum sclerostin levels were not associated with mortality (HR per doubling, 0.94; 95% CI, 0.76-1.17). This result was unchanged after adjustment for age, sex, dialysis vintage, diabetes, prior cardiovascular disease, and body mass index (HR per doubling, 0.92; 95% CI, 0.72-1.17). Similar results were obtained for cardiovascular mortality. CONCLUSION: Serum sclerostin levels were not associated with mortality in maintenance hemodialysis patients. Further research is required to determine the role of sclerostin in vascular calcification and cardiovascular disease in kidney failure.

Hyporesponsiveness to erythropoiesis-stimulating agent in non-dialysis-dependent CKD patients: The BRIGHTEN study.

Among non-dialysis-dependent chronic kidney disease (ND-CKD) patients, a low hematopoietic response to erythropoiesis-stimulating agents (ESAs) is a predictor for poor renal and cardiovascular outcome. To assess the method for evaluating hyporesponsiveness to ESA in patients with ND-CKD, a multicenter, prospective, observational study of 1,980 adult patients with ND-CKD with renal anemia was conducted. Darbepoetin alfa (DA) and iron supplement administrations were provided according to the recommendation of the attached document and the guidelines of JSDT (Japanese Society of Dialysis and Transplantation). The primary outcomes were progression of renal dysfunction and major adverse cardiovascular events. ESA responsiveness was assessed using pre-defined candidate formulae. During the mean follow-up period of 96 weeks, renal and cardiovascular disease (CVD) events occurred in 683 (39.6%) and 174 (10.1%) of 1,724 patients, respectively. Among pre-set candidate formulae, the one expressed by dividing the dose of DA by Hb level at the 12-week DA treatment was statistically significant in predicting renal (hazard ratio [HR], 1.449; 95% confidence interval [CI], 1.231-1.705; P<0.0001) and CVD events (HR, 1.719; 95% CI, 1.239-2.386; P = 0.0010). The optimum cut-off values for both events were close to 5.2. In conclusion, hyporesponsiveness to ESA in ND-CKD cases, which is associated with a risk for renal and CVD events, may be evaluated practicably as the dose of DA divided by the Hb level at the 12-week DA treatment, and the cut-off value of this index is 5.2. A search for the causes of poor response and measures for them should be recommended in such patients. Trial registration: ClinicalTrials. gov Identifier: NCT02136563; UMIN Clinical Trial Registry Identifier: UMIN000013464.