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BackgroundInhibitors of vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) signaling, such as bevacizumab (Bmab), are used for the treatment of various advanced cancers. However, these inhibitors induce renal thrombotic microangiopathy (TMA). Recently, two European cohort studies showed a distinctive histopathological pseudothrombotic pattern different from TMA in Bmab-treated patients.MethodsWe analyzed 9 renal biopsies from proteinuric cancer patients treated with VEGF-VEGFR2 inhibitors in our Japanese cohort. Clinical and laboratory features were also assessed in these patients.ResultsAll 9 patients had moderate to heavy proteinuria with normal or slightly elevated serum creatinine levels. On light microscopy, a patchy pattern of hemispherical/spherical lesions along glomerular capillary walls was a characteristic finding. On immunofluorescence microscopy, staining for immunoglobulins (IgM dominant) at varying intensities was observed mainly along glomerular capillary walls. Especially, hemispherical/spherical positive staining for immunoglobulins was a characteristic pattern. Immunohistochemical studies showed positive staining for immunoglobulins and negative staining for CD61-positive platelets in capillary hemispherical/spherical lesions and positive VEGF staining in podocytes. On electron microscopy, variably electron-dense material in dilated glomerular capillaries and partial effacement of podocyte foot processes were observed. After the withdrawal of VEGF-VEGFR2 inhibitors, proteinuria improved without any specific treatment in 8 patients.ConclusionsHistopathological findings in our patients treated with VEGF-VEGFR2 inhibitors were consistent with those observed in the recently described new form of Bmab-associated hyaline occlusive glomerular microangiopathy. This form should be considered in proteinuric cancer patients treated with VEGF-VEGFR2 inhibitors. Discontinuing VEGF-VEGFR2 inhibitors may lead to improvement of glomerular microangiopathy induced by these drugs.

It has been reported that certain microRNAs (miRNA) are associated with the pathogenesis of lymphoma. We have previously demonstrated that histone deacetylase inhibitors restore tumor‐suppressive miRNAs, such as miR‐16, miR‐29, miR‐150, and miR‐26, in advanced cutaneous T‐cell lymphoma (CTCL). Among these, the function of miR‐26 remains unclear. In this study, we aimed to reveal the function of miR‐26 in CTCL oncogenesis. First, we confirmed that the miR‐26 family was markedly dysregulated in CTCL cell lines and primary samples. In vivo analysis using miR‐26a‐transduced CTCL cells injected into immunodeficient NOG mice demonstrated the significant prolonged survival of the mice, suggesting that the miRNA had a tumor‐suppressive function. We performed gene expression assays and identified 12 candidate miR‐26 targets, namely RGS13, FAM71F1, OAF, SNX21, CDH2, PTPLB, IL22, DNAJB5, CASZ1, CACNA1C, MYH10, and CNR1. Among these, IL22 was the most likely candidate target because the IL‐22–STAT3–CCL20–CCR6 cascade is associated with tumor invasion and metastasis of advanced CTCL. In vitro analysis of IL22 and IL22RA knockdown and miR‐26 transduction demonstrated inhibited CTCL cell migration. In particular, IL22 knockdown induced cell apoptosis. Finally, we conducted in vivo inoculation analysis of mice injected with shIL22‐transfected CTCL cells, and found no tumor invasion or metastasis in the inoculated mice, although the control mice showed multiple tumor invasions and metastases. These results, along with our previous data, demonstrated that miR‐26 is a tumor suppressor that is associated with tumor invasion and the metastasis of advanced CTCL by regulating the IL‐22–STAT3–CCL20 cascade. Therefore, a IL‐22‐targeting therapy could be a novel therapeutic strategy for advanced CTCL. We found that IL22 is an miR‐26 target and is involved in invasion and metastasis in advanced CTCL. It is reported that high IL‐22 expression levels were observed in the serum and skin lesions of CTCL patients, suggesting that IL‐22 inhibition may be new CTCL treatment strategy. Together, we were able to provide basic evidence that the development of IL‐22 neutralizing antibody is promising for the treatment of CTCL.

Human herpesvirus-8 (HHV8)-positive, human immunodeficiency virus (HIV)-negative multicentric Castleman disease (MCD) is a rare and age-related lymphoproliferative disorder caused by cytokine storm. Rituximab treatment is currently recommended because B-cell depletion eliminates the primary reservoir for HHV8. We report the first case of effective rituximab treatment of a Japanese patient (an 87-year-old woman) with this disorder. Her inflammatory symptoms and lymphadenopathy improved after medium-dose steroid therapy, but these symptoms recurred during steroid tapering. After one course of rituximab therapy, she achieved sustained remission. HHV8-associated MCD should be considered as a possible diagnosis in HIV-negative patients with inflammatory symptoms and lymphadenopathy.

The molecular mechanisms involved in the terminal differentiation of erythroblasts have been elucidated by comparing enucleation and cell division. Although various similarities and differences between erythroblast enucleation and cytokinesis have been reported, the mechanisms that control enucleation remain unclear. We previously reported that dynein and microtubule-organizing centers mediated the polarization of nuclei in human erythroblasts. Moreover, the accumulation of F-actin was noted during the enucleation of erythroblasts. Therefore, during enucleation, upstream effectors in the signal transduction pathway regulating dynein or actin, such as cell division control protein 42 homolog (Cdc42), may be crucial. We herein investigated the effects of the Cdc42 inhibitor, CASIN, on cytokinesis and enucleation in colony-forming units-erythroid (CFU-Es) and mature erythroblasts (day 10). CASIN blocked the proliferation of CFU-Es and their enucleation in a dose-dependent manner. Dynein adopted an island-like distribution in the cytoplasm of non-treated CFU-Es, but was concentrated near the nucleus as a dot and co-localized with γ-tubulin in CASIN-treated cells. CASIN blocked the accumulation of F-actin in CFU-Es and day 10 cells. These results demonstrated that Cdc42 plays an important role in cytokinesis, nuclear polarization and nuclear extrusion through a relationship with dynein and actin filament organization during the terminal differentiation of erythroblasts.

BackgroundHigh-IgA ddY (HIGA) mice, an animal model of human IgA nephropathy (IgAN), spontaneously develop nephropathy with glomerular IgA deposition and markedly elevated serum IgA levels from 25 weeks of age.MethodsWe performed a comparative proteomic analysis of the renal proteins collected from HIGA mice and control C57BL/6 mice at 5 or 38 weeks of age (the H5, H38, C5, and C38 groups) (n = 4 in each group). Proteins were extracted from the left whole kidney of each mouse and analyzed using nano-liquid chromatography–tandem mass spectrometry. The right kidneys were used for histopathological examinations.ResultsImmunohistochemical examinations showed glomerular deposition of IgA and the immunoglobulin joining (J) chain, and increased numbers of interstitial IgA- and J-chain-positive plasma cells in the H38 group. In the proteomic analysis, > 5000 proteins were identified, and 33 proteins with H38/H5 ratios of > 5.0, H38/C38 ratios of > 5.0, and C38/C5 ratios of < 1.5 were selected. Among them, there were various proteins that are known to be involved in human IgAN and/or animal IgAN models. Immunohistochemical examinations validated the proteomic results for some proteins. Furthermore, two proteins that are known to be associated with kidney disease displayed downregulated expression (H38/H5 ratio: 0.01) in the H38 group.ConclusionsThe results of comparative proteomic analysis of renal proteins were consistent with previous histopathological and serological findings obtained in ddY and HIGA mice. Various proteins that are known to be involved in kidney disease, including IgAN, and potential disease marker proteins exhibited markedly altered levels in HIGA mice.

BackgroundThe prognostic significance of glomerular extracapillary hypercellularity (EXHC) in diabetic kidney disease (DKD) is unclear. The aim of this study was to investigate the clinicopathological features and outcomes of DKD patients with EXHC.MethodsWe studied 70 cases of renal biopsy-confirmed type 2 DKD that were diagnosed between 2004 and 2014 and compared the clinicopathological features and outcomes of 22 patients with EXHC (EXHC group) with those of 48 patients without EXHC (control group). All of the patients were Japanese. We assessed the renal biopsy specimens based on the Renal Pathology Society classification system. Clinical and laboratory data were collected at the time of the renal biopsy, and renal outcomes were assessed based on progression to end-stage renal disease (ESRD) requiring renal replacement therapy. The median duration of the observation period was 3 years.ResultsIn pathological features, nodular sclerosis (Kimmelstiel–Wilson lesions) was observed more frequently in the EXHC group than in the control group (63.6% vs. 35.4%, P = 0.027). There were no significant intergroup differences in clinical features or renal outcomes. Univariate and multivariate Cox regression analyses of all patients showed that a high level of proteinuria, a low initial eGFR, and severe interstitial inflammation were poor prognostic factors.ConclusionsEXHC is related to nodular sclerosis, which is a known risk factor for ESRD. Careful observation is needed during the follow-up of DKD patients with EXHC, although there were no significant differences in renal outcomes between the EXHC and control groups.

Although the neuronal protein α-synuclein (α-syn) is thought to play a central role in the pathogenesis of Parkinson’s disease (PD), its physiological function remains unknown. It is known that α-syn is also abundantly expressed in erythrocytes. However, its role in erythrocytes is also unknown. In the present study, we investigated the localization of α-syn in human erythroblasts and erythrocytes. Protein expression of α-syn increased during terminal differentiation of erythroblasts (from day 7 to day 13), whereas its mRNA level peaked at day 11. α-syn was detected in the nucleus, and was also seen in the cytoplasm and at the plasma membrane after day 11. In erythroblasts undergoing nucleus extrusion (day 13), α-syn was detected at the periphery of the nucleus. Interestingly, we found that recombinant α-syn binds to trypsinized inside-out vesicles of erythrocytes and phosphatidylserine (PS) liposomes. The dissociation constants for binding to PS/phosphatidylcholine (PC) liposomes of N-terminally acetylated (NAc) α-syn was lower than that of non NAc α-syn. This suggests that N-terminal acetylation plays a significant functional role. The results of the present study collectively suggest that α-syn is involved in the enucleation of erythroblasts and the stabilization of erythroid membranes.

BackgroundWe determined the usefulness and prognostic ability of the renal risk score (RRS), proposed in Europe, for Japanese patients with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN) and high myeloperoxidase (MPO)-ANCA positivity; these aspects remain to be verified.MethodsThis retrospective study was conducted on 86 Japanese patients with new, biopsy-confirmed AAGN. We calculated the RRS and analyzed the relationship between this classification, and clinicopathological features and prognosis. We also compared the predictive values between RRS for endpoints including renal death and conventional prognostic tools for patients with AAGN.ResultsThere were 33, 37, and 16 patients in the low-, medium-, and high-risk groups, respectively. All patients were MPO-ANCA positive. The median follow-up period was 33 months; 16 (18.6%) patients progressed to end-stage renal disease (ESRD). In the high-risk group, 9/16 (56.3%) patients progressed to ESRD, and renal prognosis was significantly poorer than that in other groups (low-risk group, P < 0.001; medium-risk group, P = 0.004). In Cox multivariate regression analysis, RRS was an independent, poor renal prognostic factor (hazard ratio 5.22; 95% confidence interval 2.20–12.40; P < 0.001). The receiver-operating characteristic curves of the RRS for each endpoint were comparable with those of the 2010 histological classification and those of the severity classification of Japanese rapidly progressive glomerulonephritis.ConclusionsThis is the first study to report the usefulness of the RRS for predicting renal outcomes among Japanese patients with AAGN. Our predictive value of the RRS was comparable with that of conventional prognostic tools.

BackgroundSeveral recent studies in patients with idiopathic membranous nephropathy (iMN) from Western and Asian counties showed that some single nucleotide polymorphisms (SNPs) within the PLA2R1 and HLA-DQA1 genes are significantly associated with iMN. However, there is only 1 report on analysis of PLA2R1 and HLA regions in Japanese patients with iMN.MethodsA total of 58 patients with iMN, 26 patients with secondary MN (sMN), and 50 patients with other diseases were enrolled. All patients were Japanese. We selected 6 SNPs within PLA2R1 and 1 SNP within HLA-DQA1, which were significantly associated with iMN in reported white European cohorts, and sequenced these exons using genomic DNA prepared from peripheral mononuclear cells from each patient. We then analyzed differences in PLA2R1 and HLA-DQA1 sequence variants among the 3 groups.ResultsGenotypic and allelic frequency distributions for 3 out of 6 SNPs within PLA2R1, rs3749117, rs35771982, and rs2715918 were significantly different between the iMN and control groups. Allelic frequency distributions for SNP rs2187668 within HLA-DQA1 were significantly different between the iMN and control groups. There were no correlations between PLA2R1 and HLA-DQA1 sequence variants and clinical parameters in patients with iMN. There were no significant differences in genotypic or allelic frequency distributions for examined SNPs between the sMN and control groups.ConclusionsThere are some differences in PLA2R1 SNP distributions between previously reported cohorts from other countries and our Japanese cohort of patients with iMN, while there is a significant association between SNP rs35771982 and iMN in most of reported cohorts.

Background Few studies have been conducted on the long-term prognosis of patients with amyloid light chain (AL) and amyloid A (AA) renal amyloidosis in the same cohort. Methods We retrospectively examined 68 patients with biopsy-proven renal amyloidosis (38 AL and 30 AA). Clinicopathological findings at the diagnosis and follow-up data were evaluated in each patient. We analyzed the relationship between clinicopathological parameters and survival data. Results Significant differences were observed in several clinicopathological features, such as proteinuria levels, between the AL and AA groups. Among all patients, 84.2 % of the AL group and 93.3 % of the AA group received treatments for the underlying diseases of amyloidosis. During the follow-up period (median 18 months in AL and 61 months in AA), 36.8 % of the AL group and 36.7 % of the AA group developed end-stage renal failure requiring dialysis, while 71.1 % of the AL group and 56.7 % of the AA group died. Patient and renal survivals were significantly longer in the AA group than in the AL group. eGFR of >60 mL/min/1.73 m 2 at biopsy and an early histological stage of glomerular amyloid deposition were identified as low-risk factors. A multivariate analysis showed that cardiac amyloidosis and steroid therapy significantly influenced patient and renal survivals. Conclusions Our results showed that heart involvement was the major predictor of poor outcomes in renal amyloidosis, and that the prognosis of AA renal amyloidosis was markedly better than that in previously reported cohorts. Therapeutic advances in inflammatory diseases are expected to improve the prognosis of AA amyloidosis.