A Case of Mixed Connective Tissue Disease That Transformed Into Systemic Lupus Erythematosus After a Long Clinical Course.

Mixed connective tissue disease (MCTD), a multisystem autoimmune disease that was first proposed in 1972, has overlapping features with other autoimmune diseases. In recent studies, mixed connective tissue disease has been reported to change into other connective tissue diseases (CTD; such as systemic lupus erythematosus [SLE], polymyositis, and systemic sclerosis [SSc]) in the long term. We report the case of a 58-year-old Japanese man diagnosed with mixed connective tissue disease 15 years ago. During his clinical course, he developed discoid lupus erythematosus, pancytopenia, a low complement titer, proteinuria, and hematuria. He also turned positive for the anti-double-stranded deoxyribonucleic acid (dsDNA) antibody. A kidney biopsy revealed lupus nephritis (LN) class IV. Therefore, we considered this to be a shift from mixed connective tissue disease to systemic lupus erythematosus. We changed his treatment to lupus nephritis, after which he remained in remission. Our case suggests that mixed connective tissue disease may shift to other connective tissue diseases over a long period; therefore, it is necessary to identify whether patients with mixed connective tissue disease fulfill the diagnostic criteria for other connective tissue diseases when new manifestations appear.

Soluble receptor for advanced glycation end products protects from ischemia- and reperfusion-induced acute kidney injury.

The full-length receptor for advanced glycation end products (RAGE) is a multiligand pattern recognition receptor. High-mobility group box 1 (HMGB1) is a RAGE ligand of damage-associated molecular patterns that elicits inflammatory reactions. The shedded isoform of RAGE and endogenous secretory RAGE (esRAGE), a splice variant, are soluble isoforms (sRAGE) that act as organ-protective decoys. However, the pathophysiologic roles of RAGE/sRAGE in acute kidney injury (AKI) remain unclear. We found that AKI was more severe, with enhanced renal tubular damage, macrophage infiltration, and fibrosis, in mice lacking both RAGE and sRAGE than in wild-type (WT) control mice. Using murine tubular epithelial cells (TECs), we demonstrated that hypoxia upregulated messenger RNA (mRNA) expression of HMGB1 and tumor necrosis factor α (TNF-α), whereas RAGE and esRAGE expressions were paradoxically decreased. Moreover, the addition of recombinant sRAGE canceled hypoxia-induced inflammation and promoted cell viability in cultured TECs. sRAGE administration prevented renal tubular damage in models of ischemia/reperfusion-induced AKI and of anti-glomerular basement membrane (anti-GBM) glomerulonephritis. These results suggest that sRAGE is a novel therapeutic option for AKI.

Trehalose ameliorates peritoneal fibrosis by promoting Snail degradation and inhibiting mesothelial-to-mesenchymal transition in mesothelial cells.

Peritoneal fibrosis (PF) is a severe complication of peritoneal dialysis, but there are few effective therapies for it. Recent studies have revealed a new biological function of trehalose as an autophagy inducer. Thus far, there are few reports regarding the therapeutic effects of trehalose on fibrotic diseases. Therefore, we examined whether trehalose has anti-fibrotic effects on PF. PF was induced by intraperitoneal injection of chlorhexidine gluconate (CG). CG challenges induced the increase of peritoneal thickness, ColIα1 mRNA expression and hydroxyproline content, all of which were significantly attenuated by trehalose. In addition, CG challenges induced a marked peritoneal accumulation of α-SMA+ myofibroblasts that was reduced by trehalose. The number of Wt1+ α-SMA+ cells in the peritoneum increased following CG challenges, suggesting that a part of α-SMA+ myofibroblasts were derived from peritoneal mesothelial cells (PMCs). The number of Wt1+ α-SMA+ cells was also suppressed by trehalose. Additionally, trehalose attenuated the increase of α-SMA and ColIα1 mRNA expression induced by TGF-ß1 through Snail protein degradation, which was dependent on autophagy in PMCs. These results suggest that trehalose might be a novel therapeutic agent for PF through the induction of autophagy and the suppression of mesothelial-to-mesenchymal transition in PMCs.

Relationship between anti-erythropoietin receptor autoantibodies and responsiveness to erythropoiesis-stimulating agents in patients on hemodialysis: a multi-center cross-sectional study.

BACKGROUND: A decreased response to erythropoiesis-stimulating agents (ESAs) leads to refractory anemia and worse prognosis in patients with chronic kidney disease. We examined the association between autoantibodies to the erythropoietin receptor (EPOR) and responsiveness to ESAs in patients on maintenance hemodialysis. METHODS: A total of 108 Japanese patients on maintenance hemodialysis at three institutions were enrolled. Sera from these patients were screened for anti-EPOR antibodies using an enzyme-linked immunosorbent assay. An ESA resistance index (ERI) was calculated, and patients in the highest ERI quartile were defined as ESA hyporesponsive. RESULTS: Anti-EPOR antibodies were detected in 11 patients (10%). Body mass index and hemoglobin, platelet, magnesium, and ferritin levels decreased with higher ERI levels. On the other hand, C-reactive protein (CRP) levels and the prevalence of anti-EPOR antibodies increased with higher ERI levels. In multivariate analysis, the presence of anti-EPOR antibodies together with CRP was a significant risk factor for ESA hyporesponsiveness. CONCLUSIONS: Anti-EPOR antibodies were detected in patients on maintenance hemodialysis, and these autoantibodies were independent factors for hyporesponsiveness to ESAs in these patients.

Inhibition of CTGF ameliorates peritoneal fibrosis through suppression of fibroblast and myofibroblast accumulation and angiogenesis.

Peritoneal fibrosis (PF) is a serious complication in various clinical settings, but the mechanisms driving it remain to be fully determined. Connective tissue growth factor (CTGF) is known to regulate fibroblast activities. We therefore examined if CTGF inhibition has anti-fibrotic effects in PF. PF was induced by repetitive intraperitoneal injections of chlorhexidine gluconate (CG) in mice with type I pro-collagen promoter-driven green fluorescent protein (GFP) expression to identify fibroblasts. FG-3019, an anti-CTGF monoclonal antibody, was used to inhibit CTGF. CG-induced PF was significantly attenuated in FG-3019-treated mice. CG challenges induced marked accumulations of proliferating fibroblasts and of myofibroblasts, which were both reduced by FG-3019. Levels of peritoneal CTGF expression were increased by CG challenges, and suppressed in FG-3019-treated mice. FG-3019 treatment also reduced the number of CD31+ vessels and VEGF-A-positive cells in fibrotic peritoneum. In vitro studies using NIH 3T3 fibroblasts and peritoneal mesothelial cells (PMCs) showed that CTGF blockade suppressed TGF-ß1-induced fibroblast proliferation and myofibroblast differentiation, PMC mesothelial-to-mesenchymal transition, and VEGF-A production. These findings suggest that the inhibition of CTGF by FG-3019 might be a novel treatment for PF through the regulation of fibroblast and myofibroblast accumulation and angiogenesis.