Anti-Neuron-Derived Neurotrophic Factor Antibodies in Secondary Membranous Nephropathy Caused by Syphilis: A Case Report.

We present the case of a 61-year-old man who developed nephrotic syndrome as a result of syphilis-associated secondary membranous nephropathy (MN). The patient showed nephrotic syndrome remission following antibiotic treatment for syphilis alone. Pathologically, the target antigen of immune complexes accumulated on glomerular basement membranes (GBM) in secondary MN caused by syphilis has been reported to be neuron-derived neurotrophic factor (NDNF). His renal histopathology was consistent with secondary MN caused by syphilis, with a full-house pattern on immunofluorescence microscopy, in addition to NDNF deposits that colocalized with IgG deposits granularly on the GBM. However, to date, there is no serological evidence for the involvement of NDNF in the GBM. In the present study, we found that anti-NDNF autoantibodies in the acute-phase serum disappeared in the convalescent-phase serum of a patient who recovered from syphilis and nephrotic syndrome after antibiotic therapy alone. This result supports the hypothesis that treatment of syphilis with antibiotics suppresses NDNF's antigenicity. In summary, we found new serological evidence emphasizing that NDNF is an etiological antigen in secondary MN caused by syphilis.

Multidisciplinary Prophylactic Strategies for Recurrence of Laryngeal Edema After Tooth Extraction in a Patient With Hereditary Angioedema: A Case Report.

Hereditary angioedema (HAE), caused by C1-inhibitor (C1-INH) deficiency or dysfunction, is a rare and potentially life-threatening disease that leads to unpredictable recurrent attacks of angioedema in localized regions, including the larynx. As medical or dental procedures can trigger laryngeal edema, resulting in asphyxiation, major global guidelines recommend short-term prophylaxis prior to invasive procedures and long-term prophylaxis to prevent acute attacks and achieve near-normal lives. Here, we report the case of a 63-year-old male who experienced asphyxiation after tooth extraction. Emergency tracheotomy had saved his life at the age of 40 years, before the diagnosis of HAE. At the age of 63, when he had another opportunity for tooth extraction, he was definitively diagnosed with HAE. Administering short-term prophylaxis with ongoing long-term prophylaxis for HAE and perioperative multidisciplinary management for tooth extraction helped prevent recurrent fatal angioedema due to dental procedures and this can be useful when managing patients with HAE.

Predicting dry weight change in Hemodialysis patients using machine learning.

BACKGROUND: Machine Learning has been increasingly used in the medical field, including managing patients undergoing hemodialysis. The random forest classifier is a Machine Learning method that can generate high accuracy and interpretability in the data analysis of various diseases. We attempted to apply Machine Learning to adjust dry weight, the appropriate volume status of patients undergoing hemodialysis, which requires a complex decision-making process considering multiple indicators and the patient's physical conditions. METHODS: All medical data and 69,375 dialysis records of 314 Asian patients undergoing hemodialysis at a single dialysis center in Japan between July 2018 and April 2020 were collected from the electronic medical record system. Using the random forest classifier, we developed models to predict the probabilities of adjusting the dry weight at each dialysis session. RESULTS: The areas under the receiver-operating-characteristic curves of the models for adjusting the dry weight upward and downward were 0.70 and 0.74, respectively. The average probability of upward adjustment of the dry weight had sharp a peak around the actual change over time, while the average probability of downward adjustment of the dry weight formed a gradual peak. Feature importance analysis revealed that median blood pressure decline was a strong predictor for adjusting the dry weight upward. In contrast, elevated serum levels of C-reactive protein and hypoalbuminemia were important indicators for adjusting the dry weight downward. CONCLUSIONS: The random forest classifier should provide a helpful guide to predict the optimal changes to the dry weight with relative accuracy and may be useful in clinical practice.

Inhibition of Importin- α -Mediated Nuclear Localization of Dendrin Attenuates Podocyte Loss and Glomerulosclerosis.

SIGNIFICANCE STATEMENT: Nuclear translocation of dendrin is observed in injured podocytes, but the mechanism and its consequence are unknown. In nephropathy mouse models, dendrin ablation attenuates proteinuria, podocyte loss, and glomerulosclerosis. The nuclear translocation of dendrin promotes c-Jun N -terminal kinase phosphorylation in podocytes, altering focal adhesion and enhancing cell detachment-induced apoptosis. We identified mediation of dendrin nuclear translocation by nuclear localization signal 1 (NLS1) sequence and adaptor protein importin- α . Inhibition of importin- α prevents nuclear translocation of dendrin, decreases podocyte loss, and attenuates glomerulosclerosis in nephropathy models. Thus, inhibiting importin- α -mediated nuclear translocation of dendrin is a potential strategy to halt podocyte loss and glomerulosclerosis. BACKGROUND: Nuclear translocation of dendrin is observed in the glomeruli in numerous human renal diseases, but the mechanism remains unknown. This study investigated that mechanism and its consequence in podocytes. METHODS: The effect of dendrin deficiency was studied in adriamycin (ADR) nephropathy model and membrane-associated guanylate kinase inverted 2 ( MAGI2 ) podocyte-specific knockout ( MAGI2 podKO) mice. The mechanism and the effect of nuclear translocation of dendrin were studied in podocytes overexpressing full-length dendrin and nuclear localization signal 1-deleted dendrin. Ivermectin was used to inhibit importin- α . RESULTS: Dendrin ablation reduced albuminuria, podocyte loss, and glomerulosclerosis in ADR-induced nephropathy and MAGI2 podKO mice. Dendrin deficiency also prolonged the lifespan of MAGI2 podKO mice. Nuclear dendrin promoted c-Jun N -terminal kinase phosphorylation that subsequently altered focal adhesion, reducing cell attachment and enhancing apoptosis in cultured podocytes. Classical bipartite nuclear localization signal sequence and importin- α mediate nuclear translocation of dendrin. The inhibition of importin- α / ß reduced dendrin nuclear translocation and apoptosis in vitro as well as albuminuria, podocyte loss, and glomerulosclerosis in ADR-induced nephropathy and MAGI2 podKO mice. Importin- α 3 colocalized with nuclear dendrin in the glomeruli of FSGS and IgA nephropathy patients. CONCLUSIONS: Nuclear translocation of dendrin promotes cell detachment-induced apoptosis in podocytes. Therefore, inhibiting importin- α -mediated dendrin nuclear translocation is a potential strategy to prevent podocyte loss and glomerulosclerosis.

Hereditary angioedema with an acute attack resolved after bone marrow transplantation for acute myeloid leukemia: a case report.

BACKGROUND: Hereditary angioedema (HAE), which is caused by C1-inhibitor (C1-INH) deficiency or dysfunction, is a rare and potentially life-threatening disease. In patients with HAE, excess production of bradykinin causes acute unpredictable recurrent attacks of angioedema in localized regions, including the larynx and intestines. Given the fact that HAE is an autosomal dominant disease, C1-INH produced in patients with HAE is 50% of that produced in healthy individuals. However, most patients with HAE present plasma C1-INH function of < 25% owing to the chronic consumption of C1-INH by kallikrein-kinin, contact, complement, coagulation, and fibrinolysis cascades. Recently, several therapeutic options have been developed for acute attacks and prophylaxis in the treatment of HAE; however, currently, there is no curative therapy for HAE. CASE PRESENTATION: Here we report the case of a 48-year-old male patient who presented with a long-standing history of HAE and underwent bone marrow transplantation (BMT) for acute myeloid leukemia (AML) at the age of 39 years and has been in complete remission of AML and HAE thereafter. Notably, after BMT, his C1-INH function gradually increased as follows: < 25%, 29%, 37%, and 45.6%. Since his 20 s, he intermittently presented with an acute attack of HAE once every 3 months from the initial attack. Further, after undergoing BMT, the number of acute attacks decreased to twice within 4 years until the age of 45 years, and subsequently, the patient has been free of acute attacks. C1-INH is mainly synthesized by hepatocytes, but it is known to be partially produced and secreted from peripheral blood monocytes, macrophages, endothelial cells, and fibroblasts. We speculate that the C1-INH function may be increased by extrahepatic production of C1-INH, possibly synthesized by differentiated cells derived from hematopoietic and mesenchymal stem cells after BMT. CONCLUSIONS: This case report supports efforts to focus on extrahepatic production of C1-INH in the next strategy of new treatment development for HAE.

IgA-dominant infection-related glomerulonephritis with NAPlr-positive tubulointerstitial nephritis.

Infection-related glomerulonephritis (IRGN) is one of the most common causes of acute kidney injury (AKI). Positive glomerular staining of the nephritis-associated plasmin receptor (NAPlr) has been reported as a useful biomarker of IRGN. Although the infection can provoke acute tubulointerstitial nephritis (AIN), there are few reports of positive staining for NAPlr with AIN. We report a case of methicillin-sensitive Staphylococcus aureus (MSSA) infection-related nephritis complicated with AIN, which showed positive staining for tubulointerstitial NAPlr. The patient developed AKI and nephrotic syndrome during an intraperitoneal MSSA infection. A diagnosis of IRGN complicated by infection-related acute tubulointerstitial nephritis (IRAIN) was made based on glomerular endocapillary proliferation with tubulointerstitial infiltrating cells and tubular atrophy. Tubulointerstitial infiltrating cells were positive for NAPlr staining and plasmin activity. Treatment of the infection by antibiotics and drainage did not improve the AKI, but steroid administration improved that. NAPlr evaluation is a helpful tool for identifying causes of AIN during infection.

A rare case of nephrotic syndrome associated with Dent's disease: a case report.

Dent's disease is a rare X-linked condition caused by a mutation in CLCN5 and OCRL gene, which impair the megalin-cubilin receptor-mediated endocytosis in kidney's proximal tubules. Thus, it may manifest as nephrotic-range low-molecular-weight proteinuria (LMWP). On the other hand, glomerular proteinuria, hypoalbuminemia, and edema formation are the key features of nephrotic syndrome that rarely found in Dent's disease. Here, we reported a man in his 30 s with Dent's disease presented with leg edema for 5 days. The laboratory results revealed hypoalbuminemia and a decrease of urine ß2-microglobulin/urine protein ratio (Uß2-MG /UP), indicating that the primary origin of proteinuria shifted from LMWP to glomerular proteins. The kidney biopsy revealed glomerular abnormality and calcium deposition in the renal medulla. Electron microscopy of the kidney tissue indicated extensive foot-process effacement of the glomerular podocytes and degeneration of tubular epithelium. After a combination of treatment with prednisolone and cyclosporine (CyA), the nephrotic syndrome was remitted. Given the atypical clinical presentation and the shift of LMWP to glomerular proteinuria in this patient, glomerulopathy and the Dent's disease existed separately in this patient.

MAGI-2 and scaffold proteins in glomerulopathy.

In many cells and tissues, including the glomerular filtration barrier, scaffold proteins are critical in optimizing signal transduction by enhancing structural stability and functionality of their ligands. Recently, mutations in scaffold protein membrane-associated guanylate kinase inverted 2 (MAGI-2) encoding gene were identified among the etiology of steroid-resistant nephrotic syndrome. MAGI-2 interacts with core proteins of multiple pathways, such as transforming growth factor-ß signaling, planar cell polarity pathway, and Wnt/ß-catenin signaling in podocyte and slit diaphragm. Through the interaction with its ligand, MAGI-2 modulates the regulation of apoptosis, cytoskeletal reorganization, and glomerular development. This review aims to summarize recent findings on the role of MAGI-2 and some other scaffold proteins, such as nephrin and synaptopodin, in the underlying mechanisms of glomerulopathy.

Impact of anaemia treatment for left ventricular remodelling prior to initiation of dialysis in chronic kidney disease patients: Efficacy and stability of long acting erythropoietin stimulating agents.

AIM: Anaemia is a common complication in patients with chronic kidney disease (CKD), which may initiate or accelerate left ventricular (LV) hypertrophy (LVH). The present study is a retrospective analysis to assess whether anaemia treatment is independently associated with LV remodelling prior to initiation of dialysis in CKD patients. METHODS: Biochemical and physical values were collected over a period of more than 120 days prior to the initiation of dialysis in 27 patients with CKD. The left ventricular mass index (LVMI) was evaluated by echocardiography twice (at the baseline and the follow-up at the initiation of the dialysis period). RESULTS: Patients using long-acting erythropoietin stimulating agents (L-ESA) had the tendency of maintaining higher levels of haemoglobin (Hb) than those using short-acting ESA (S-ESA). Patients using L-ESA showed a more significant improvement in the erythropoietin resistance index (ERI) than those of using S-ESA. In a multivariate regression analysis, the average Hb level for the observational period, the level of Hb at the initiation of dialysis and the use of L-ESA were independently associated factors for the LVMI at the initiation of dialysis. A lower LVMI at the initiation of dialysis and an improvement of the LVMI during the observational period were detected in the highest tertile of average Hb (10.4 g/dL). CONCLUSION: Long-acting ESA was effective and stable when treating anaemia until the start of dialysis. It is important to treat anaemia for the prevention of LV remodelling in CKD patients. These findings have some therapeutic implications for treatment strategies for pre-dialysis patients.

Uncoupling of glomerular IgA deposition and disease progression in alymphoplasia mice with IgA nephropathy.

Previous clinical and experimental studies have indicated that cells responsible for IgA nephropathy (IgAN), at least in part, are localized in bone marrow (BM). Indeed, we have demonstrated that murine IgAN can be experimentally reconstituted by bone marrow transplantation (BMT) from IgAN prone mice in not only normal mice, but also in alymphoplasia mice (aly/aly) independent of IgA+ cells homing to mucosa or secondary lymphoid tissues. The objective of the present study was to further assess whether secondary lymph nodes (LN) contribute to the progression of this disease. BM cells from the several lines of IgAN prone mice were transplanted into aly/aly and wild-type mice (B6). Although the transplanted aly/aly showed the same degree of mesangial IgA and IgG deposition and the same serum elevation levels of IgA and IgA-IgG immune-complexes (IC) as B6, even in extent, the progression of glomerular injury was observed only in B6. This uncoupling in aly/aly was associated with a lack of CD4+ T cells and macrophage infiltration, although phlogogenic capacity to nephritogenic IC of renal resident cells was identical between both recipients. It is suggested that secondary LN may be required for the full progression of IgAN after nephritogenic IgA and IgA/IgG IC deposition.

Dietary zinc is a key environmental modifier in the progression of IgA nephropathy.

IgA nephropathy (IgAN) shows diverse epidemiological characteristics, resulting from both genetic and acquired (e.g., environmental) causes. Environmental factors, such as diet or exposure to exogenous antigens, may prescribe the progression or prognosis of IgAN. It remains unclear as to how diet and infection influence susceptibility to IgAN. A relationship, such as Toll-like receptors (TLRs), especially TLR9 and TLR4, was demonstrated between IgAN and pathogen-recognition molecules. Recently, zinc (Zn) was discovered to be involved in various immune-related diseases, affecting B, T, and dendritic cells (DCs). This study investigates the relationship between dietary Zn and IgAN development in IgAN-prone mice. Seven-week-old IgAN-prone mice were divided into low, normal, and high Zn diet groups. To assess exogenous pathogen-mediated immune responses, lipopolysaccharide (LPS) was nasally administered. The activity of IgAN was biochemically and pathologically evaluated during the disease course. We also examined in vitro IgA production in spleen cells or in combinations of cocultured B, T, and DCs under various Zn conditions with or without LPS. Dietary conditioning with Zn affected serum immunoglobulins and urinary albumin levels, and mesangial deposition of IgA and IgG. Zn deficiency is associated with IgAN progression through the activation of the TLR4/TIR-domain-containing adapter-inducing interferon-ß (TRIF), but not the TLR9, in DCs. Zn supplementation prevented disease aggravation. Our findings indicate that immune conditioning with dietary Zn alters nephritogenic IgA production after mucosal infection.

Reevaluation of the mucosa-bone marrow axis in IgA nephropathy with animal models.

Impaired immune regulation along the 'mucosa-bone marrow axis' has been postulated to play an important role in the pathogenesis of IgA nephropathy (IgAN). Animal models have allowed us to study such changes in detail. Recently, we established several useful animal models, including IgAN-prone mice. Using these animal models, our group is approaching the underlying mechanisms by which bone marrow and mucosal cell interrelate and finally induce this disease. Accumulating evidence from these approaches suggests that there is dysregulation of innate and cellular immunity in IgAN resulting in changes in the mucosal immune system. These changes appear to be closely linked to disruption of mucosal tolerance, resulting in abnormal priming and dissemination of cells to sites such as the bone marrow where they are responsible for synthesis of nephritogenic IgA. Our clinical studies further support these ideas and indicate that the tonsils may be a major mucosal priming site in human IgAN. In addition, our findings also suggest clinical application of nephritogenic IgA (IgA1) as a biological marker and possible future treatment strategies that focus on manipulating the priming and dissemination of these memory cells in order to prevent the appearance of nephritogenic IgA (IgA1) in the systemic compartment.

Toll-like receptor 9 affects severity of IgA nephropathy.

Environmental pathogens are suspected to aggravate renal injury in IgA nephropathy (IgAN), but neither underlying mechanisms nor specific exogenous antigens have been identified. In this study, a genome-wide scan of ddY mice, which spontaneously develop IgAN, was performed, and myeloid differentiation factor 88 (MyD88) was identified as a candidate gene for progression of renal injury (chi(2) = 21.103, P = 0.00017). For evaluation of the potential influence of environmental pathogens on progression of renal injury, ddY mice were housed in either conventional or specific pathogen-free conditions. Expression of genes encoding toll-like receptors (TLR) and the signaling molecule MyD88 were quantified by real-time reverse transcription-PCR in splenocytes. Although the housing conditions did not affect the prevalence of IgAN, the severity of renal injuries was higher in the conventionally housed group. Mice that had IgAN and were housed in conventional conditions had higher levels of TLR9 and MyD88 transcripts than mice that had IgAN and were housed in specific pathogen-free conditions. Furthermore, nasal challenge with CpG-oligodeoxynucleotides, which are ligands for TLR9, aggravated renal injury, led to strong Th1 polarization, and increased serum and mesangial IgA. For investigation of whether these results may be generalizable to humans, single-nucleotide polymorphisms in the TLR9 and MyD88 genes were analyzed in two cohorts of patients with IgAN; an association was observed between TLR9 polymorphisms and disease progression. In summary, these findings suggest that activation of the TLR9/MyD88 pathway by common antigens may affect the severity of IgAN.

Roles of bone marrow, mucosa and lymphoid tissues in pathogenesis of murine IgA nephropathy.

Previous studies indicated that bone marrow cells may contribute to the pathogenesis of IgA nephropathy (IgAN). However, the cell types and mechanisms responsible remain unclear. Our recent study showed that 'grouped ddY mice' is a useful model to approach the pathogenesis of IgAN. Moreover, we also reported that bone marrow transplantation (BMT) from the onset mice of this model reconstituted IgAN in healthy recipients with strong Th1-polarization. We aimed to examine the roles of bone marrow (BM) cells, mucosa and lymphoid tissues in IgAN. We employed onset ddY mice and mutant mice lacking all systemic lymph nodes, Payer's patch, isolated lymphoid follicles in the lamina propria (LP) and IgA producing cells. BM cells from the onset mice were transplanted into the mutant and wild type (C57BL/6:B6). After BMT, serum elevation of IgA and IgA(+)B220(-) plasma cells in BM, but not IgA producing cells in LP, were observed in the mutant mice. Although both transplanted mice showed mesangial IgA deposition, glomerular lesions with IgG2a co-deposition were detected only in B6 mice. The present results suggest that glomerular IgA deposition, but not glomerular damage, can be induced by BM-derived or -primed IgA-producing cells independently of priming in mucosa and secondary lymphoid tissues.

[Comparison of prediction equations of glomerular filtration rate in Japanese adults].

OBJECTIVE: Creatinine clearance (Ccr) is widely used for the evaluation of the glomerular filtration rate (GFR). Since the clearance method requires urine collection, formulae for predicting GFR without urine collection have been developed. In the guidelines of the Kidney Disease Outcomes Quality Initiative(K/ DOQI), the formulae developed from the Modification of Diet in Renal Disease Study (MDRD) are recommended for estimating GFR. The objective of the present study is to compare measured Ccr and Ccr estimated by the Cockcroft-Gault, Horio and MDRD equations in Japanese adults. MATERIALS AND METHODS: In 100 inpatients (67 men and 33 women) in this hospital, we evaluated the correlation between measured Ccr derived from 24-hour urinary collections and predicted Ccr or GFR calculated using the Cockcroft-Gault, Horio, and MDRD equations. RESULTS: The equation of linear regression is given as y = 0.8165x+2.1229 (r = 0.9415, p < 0.0001) by the Cockcroft-Gault formula, y = 0.7478x+1.6757 (r = 0.9458, p < 0.0001) by the Horio formula and y = 0.8335x+4.4261 (r = 0.9209, p < 0.0001) by the MDRD formula (y : measured Ccr, x : estimated Ccr or GFR). These predictive formulae demonstrated a strong correlation. CONCLUSION: Although the Cockcroft-Gault formula derived from Japanese patients demonstrated the highest correlation with Ccr, both the Horio formula and the MDRD formula also showed a high correlation. These predictive formulae could be useful for the prediction of Ccr in Japanese patients.