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Mesenchymal stem cell (MSC) is a promising tool for the therapy of immune disorders. However, their efficacy and mechanisms in treating allergic skin disorders are less verified. We sought to investigate the therapeutic efficacy of human umbilical cord blood-derived MSCs (hUCB-MSCs) against murine atopic dermatitis (AD) and to explore distinct mechanisms that regulate their efficacy. AD was induced in mice by the topical application of Dermatophagoides farinae. Na€ ıve or activated-hUCB-MSCs were administered to mice, and clinical severity was determined. The subcutaneous administration of nucleotide-binding oligomerization domain 2 (NOD2)-activated hUCBMSCs exhibited prominent protective effects against AD, and suppressed the infiltration and degranulation of mast cells (MCs). A b-hexosaminidase assay was performed to evaluate the effect of hUCB-MSCs on MC degranulation. NOD2-activated MSCs reduced the MC degranulation via NOD2-cyclooxygenase-2 signaling. In contrast to bone marrow-derived MSCs, hUCB-MSCs exerted a cell-to-cell contact-independent suppressive effect on MC degranulation through the higher production of prostaglandin E 2 (PGE 2 ). Additionally, transforming growth factor (TGF)-b1 production from hUCB-MSCs in response to interleukin-4 contributed to the attenuation of MC degranulation by downregulating FceRI expression in MCs. In conclusion, the subcutaneous application of NOD2-activated hUCB-MSCs can efficiently ameliorate AD, and MSC-derived PGE 2 and TGF-b1 are required for the inhibition of MC degranulation.

Previous studies have addressed the differences in risk factors and stroke mechanisms between ICAS and ECAS, 2,3 but the results are inconsistent. Whereas some reported that hypertension, diabetes mellitus, and metabolic syndrome (MetS) are more closely associated with ICAS, 4-8 this was not confirmed by others. 9-11 It also remains unclear whether the risk factors and stroke mechanisms differ between anterior and posterior circulation atherosclerosis. 12Previous studies examined a small number of patients at single hospitals. 6,7,11 Most importantly, prospective studies that used detailed examinations, including advanced brain and vascular imaging, are scarce. The purpose of this study was to elucidate the differences in the risk factors and mechanisms of stroke between ICAS and ECAS, and between anterior and posterior circulation atherosclerosis. We developed a Background and Purpose-The aim of this study was to investigate differences in risk factors and stroke mechanisms between intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) and between anterior and posterior circulation atherosclerosis. Methods-A multicenter, prospective, Web-based registry was performed on atherosclerotic strokes using diffusionweighted magnetic resonance imaging and magnetic resonance angiography. Stroke mechanisms were categorized as artery-to-artery embolism, in situ thrombo-occlusion, local branch occlusion, or hemodynamic impairment. Results-One-thousand patients were enrolled from 9 university hospitals. Age (odds ratio [OR]

Rheumatoid arthritis (RA) is a long-lasting intractable autoimmune disorder, which has become a substantial public health problem. Despite widespread use of biologic drugs, there have been uncertainties in efficacy and long-term safety. Mesenchymal stem cells (MSCs) have been suggested as a promising alternative for the treatment of RA because of their immunomodulatory properties. However, the precise mechanisms of MSCs on RA-related immune cells are not fully elucidated. The aim of this study was to investigate the therapeutic potential of human umbilical cord blood-derived MSCs (hUCB-MSCs) as a new therapeutic strategy for patients with RA and to explore the mechanisms underlying hUCB-MSC-mediated immunomodulation. Mice with collagen-induced arthritis (CIA) were administered with hUCB-MSCs after the onset of disease, and therapeutic efficacy was assessed. Systemic delivery of hUCB-MSCs significantly ameliorated the severity of CIA to a similar extent observed in the etanercept-treated group. hUCB-MSCs exerted this therapeutic effect by regulating macrophage function. To verify the regulatory effects of hUCB-MSCs on macrophages, macrophages were co-cultured with hUCB-MSCs. The tumor necrosis factor (TNF)-α-mediated activation of cyclooxygenase-2 and TNF-stimulated gene/protein 6 in hUCB-MSCs polarized naive macrophages toward an M2 phenotype. In addition, hUCB-MSCs down-regulated the activation of nucleotide-binding domain and leucine-rich repeat pyrin 3 inflammasome via a paracrine loop of interleukin-1β signaling. These immune-balancing effects of hUCB-MSCs were reproducible in co-culture experiments using peripheral blood mononuclear cells from patients with active RA. hUCB-MSCs can simultaneously regulate multiple cytokine pathways in response to pro-inflammatory cytokines elevated in RA microenvironment, suggesting that treatment with hUCB-MSCs could be an attractive candidate for patients with treatment-refractory RA.

Background and Purpose-An optimal strategy for management of symptomatic intracranial atherosclerotic stenosis (ICAS) has not yet been established. We compared the efficacy of 2 combinations of antiplatelets, aspirin plus cilostazol (cilostazol group) verus aspirin plus clopidogrel (clopidogrel group), on the progression of ICAS, which is known to be associated with clinical stroke recurrence. Methods-In this investigator-initiated double-blind trial, 457 patients with acute symptomatic stenosis in the M1 segment of the middle cerebral artery or the basilar artery were randomly allocated into either a cilostazol group or a clopidogrel group. After 7 months of treatment, follow-up MR angiogram and MRI were performed. The primary end point was the progression of ICAS in comparison with stenosis on the baseline MR angiogram. Secondary end points included the occurrence of new ischemic lesions on MRI, composite of cardiovascular events, and major bleeding complications. Results-Cardiovascular events occurred in 15 of 232 patients (6.4%) in the cilostazol group and 10 of 225 (4.4%) in the clopidogrel group (Pϭ0.312). Cilostazol did not reduce the progression of symptomatic ICAS (20 of 202) compared to clopidogrel (32 of 207) (odds ratio, 0.61; Pϭ0.092), although favorable changes in serum lipoproteins were observed in the cilostazol group. There were no significant differences between the 2 groups with respect to new ischemic lesions (18.7% versus 12.0%; Pϭ0.078) and major hemorrhagic complications (0.9% versus 2.6%; Pϭ0.163). Conclusions-This trial failed to show significant difference in preventing progression of ICAS and new ischemic lesions between the 2 combination antiplatelet therapies in the patients with symptomatic ICAS. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00130039.

Our in vivo data further suggest that the immune-mediated pathologic process occurring in NMO spares most of the cortex. NMO differs from multiple sclerosis, where CLs and atrophy are frequently found, even in early disease phases. Thus, MRI analysis of the cortex may be a potential diagnostic tool, especially in ambiguous cases.

Because human mesenchymal stem cells (hMSC) have profound immunomodulatory effects, many attempts have been made to use hMSCs in preclinical and clinical trials. For hMSCs to be used in therapy, a large population of hMSCs must be generated by in vitro expansion. However, the immunomodulatory changes following the in vitro expansion of hMSCs have not been elucidated. In this study, we evaluated the effect of replicative senescence on the immunomodulatory ability of hMSCs in vitro and in vivo. Late-passage hMSCs showed impaired suppressive effect on mitogen-induced mononuclear cell proliferation. Strikingly, late-passage hMSCs had a significantly compromised protective effect against mouse experimental colitis, which was confirmed by gross and histologic examination. Among the anti-inflammatory cytokines, the production of prostaglandin E2 (PGE2) and the expression of its primary enzyme, cyclooxygenase-2 (COX-2), were profoundly increased by pre-stimulation with interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α), and this response was significantly decreased with consecutive passages. We demonstrated that the impaired phosphorylation activity of p38 MAP kinase (p38 MAPK) in late-passage hMSCs led to a compromised immunomodulatory ability through the regulation of COX-2. In conclusion, our data indicate that the immunomodulatory ability of hMSCs gradually declines with consecutive passages via a p38-mediated alteration of COX-2 and PGE2 levels.

Mesenchymal stem cell (MSC) has been applied for the therapy of allergic disorders due to its beneficial immunomodulatory abilities. However, the underlying mechanisms for therapeutic efficacy are reported to be diverse according to the source of cell isolation or the route of administration. We sought to investigate the safety and the efficacy of human adipose tissue-derived MSCs (hAT-MSCs) in mouse atopic dermatitis (AD) model and to determine the distribution of cells after intravenous administration. Murine AD model was established by multiple treatment of Dermatophagoides farinae. AD mice were intravenously infused with hAT-MSCs and monitored for clinical symptoms. The administration of hAT-MSCs reduced the gross and histological signatures of AD, as well as serum IgE level. hAT-MSCs were mostly detected in lung and heart of mice within 3 days after administration and were hardly detectable at 2 weeks. All of mice administered with hAT-MSCs survived until sacrifice and did not demonstrate any adverse events. Co-culture experiments revealed that hAT-MSCs significantly inhibited the proliferation and the maturation of B lymphocytes via cyclooxygenase (COX)-2 signaling. Moreover, mast cell (MC) degranulation was suppressed by hAT-MSC. In conclusion, the intravenous infusion of hAT-MSCs can alleviate AD through the regulation of B cell function.