Masanao Nasuno

Conditioned mesenchymal stem cells produce pleiotropic gut trophic factors.

BackgroundAlthough mounting evidence implicates mesenchymal stem cells (MSCs) in intestinal tissue repair, controversy remains regarding the engraftment, proliferation, and differentiation for repopulating MSCs in recipient tissues. Therefore, we investigated the paracrine and/or endocrine role of MSCs in experimental colitis.MethodsWe analyzed the therapeutic effects of MSC-conditioned medium (MSC-CM) on dextran sulfate sodium (DSS)- or 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. We investigated the effects of MSC-CM on the epithelial cell viability, mobility, cell cycle, and cytokine production in ex vivo lamina propria/mesenteric lymphocytes, a macrophage cell line, and the mixed lymphocyte reaction. An optimal regimen against colitis was explored. The contents of MSC-CM were analyzed using a WNT signaling pathway polymerase chain reaction array, an inflammatory cytokines antibody array, and liquid chromatography-tandem mass spectrometry analysis.ResultsIndependent of the systemic administration route, MSC-CM concentrates were effective for the inductive phase of TNBS-induced colitis and for the recovery phase of DSS-induced colitis. Hypoxia appeared to be one of the optimal preconditioning factors assessed by cell motility and viability through activating the PI3K-Akt pathway in rat small intestine epithelial cells, IEC-6. Thus, Hypoxia had profound effects on the contents of MSC-CM, which comprised pleiotropic gut trophic factors involved in each wound healing process, including the anti-inflammatory, proliferative, and tissue remodeling phases.ConclusionsIdentification and optimization of potential gut trophic factors in MSC-CM is urgently needed to form the basis for new drug discovery and for optimizing cell-based therapies for inflammatory bowel disease.

Mesenchymal Stem Cells Cancel Azoxymethane‐Induced Tumor Initiation

The role of mesenchymal stem cells (MSCs) in tumorigenesis remains controversial. Therefore, our goal was to determine whether exogenous MSCs possess intrinsic antineoplastic or proneoplastic properties in azoxymethane (AOM)‐induced carcinogenesis. Three in vivo models were studied: an AOM/dextran sulfate sodium colitis‐associated carcinoma model, an aberrant crypt foci model, and a model to assess the acute apoptotic response of a genotoxic carcinogen (AARGC). We also performed in vitro coculture experiments. As a result, we found that MSCs partially canceled AOM‐induced tumor initiation but not tumor promotion. Moreover, MSCs inhibited the AARGC in colonic epithelial cells because of the removal of O6‐methylguanine (O6MeG) adducts through O6MeG‐DNA methyltransferase activation. Furthermore, MSCs broadly affected the cell‐cycle machinery, potentially leading to G1 arrest in vivo. Coculture of IEC‐6 rat intestinal cells with MSCs not only arrested the cell cycle at the G1 phase, but also induced apoptosis. The anti‐carcinogenetic properties of MSCs in vitro required transforming growth factor (TGF)‐β signaling because such properties were completely abrogated by absorption of TGF‐β under indirect coculture conditions. MSCs inhibited AOM‐induced tumor initiation by preventing the initiating cells from sustaining DNA insults and subsequently inducing G1 arrest in the initiated cells that escaped from the AARGC. Furthermore, tumor initiation perturbed by MSCs might potentially dysregulate WNT and TGF‐β‐Smad signaling pathways in subsequent tumorigenesis. Obtaining a better understanding of MSC functions in colon carcinogenesis is essential before commencing the broader clinical application of promising MSC‐based therapies for cancer‐prone patients with inflammatory bowel disease. Stem Cells 2014;32:913–925

Contextual niche signals towards colorectal tumor progression by mesenchymal stem cell in the mouse xenograft model

BackgroundThe role of mesenchymal stem/stromal cells (MSCs) in tumorigenesis remains controversial. This study aimed to determine whether heterotypic interactions between MSCs and colon cancer cells can supply contextual signals towards tumor progression.MethodsXenografts consisting of co-implanted human colorectal cancer cells with rat MSCs in immunodeficient mice were evaluated by tumor progression, angiogenic profiles, and MSC fate. Furthermore, we investigated how MSCs function as a cancer cell niche by co-culture experiments in vitro.ResultsTumor growth progressed in two ways, either independent of or dependent on MSCs. Such cell line-specific dependency could not be explained by host immune competency. COLO 320 xenograft angiogenesis was MSC-dependent, but less dependent on vascular endothelial growth factor (VEGF), whereas HT-29 angiogenesis was not MSC-dependent, but was VEGF-dependent. MSCs and COLO 320 cells established a functional positive feedback loop that triggered formation of a cancer cell niche, leading to AKT activation. Subsequently, MSCs differentiated into pericytes that enhanced angiogenesis as a perivascular niche. In contrast, the MSC niche conferred an anti-proliferative property to HT-29 cells, through mesenchymal–epithelial transition resulting in p38 activation.ConclusionsIn conclusion, MSCs demonstrate pleiotropic capabilities as a cancer cell or perivascular niche to modulate colorectal cancer cell fate in a cell line-dependent manner in a xenogeneic context.

Short- and Long-Term Outcomes of Infliximab Treatment for Steroid-Refractory Ulcerative Colitis and Related Prognostic Factors: A Single-Center Retrospective Study

Background/Aims: The aim of this study was to analyze the short- and long-term outcomes of infliximab (IFX) treatment to cure steroid-refractory ulcerative colitis (UC) and related prognostic factors. Methods: Retrospective data were collected from 125 patients with steroid-refractory UC who received IFX treatment at our center from July 2005 to November 2013. The Lichtiger clinical activity index score was calculated at baseline, 2 weeks, 6 weeks, and 1 year, and the cumulative non-colectomy rate following IFX administration was estimated. Remission rate prognostic factors and the cumulative colectomy rate prognostic factors were evaluated using multivariate logistic regression analysis and multivariate Cox regression analysis, respectively. Results: Remission rates at 2 weeks, 6 weeks, and 1 year were 46, 58, and 45%, respectively. The 1-, 3-, and 5-year cumulative non-colectomy rates were 80, 78, and 75%, respectively. Previous treatment with calcineurin inhibitors was a significant prognostic factor for lower remission and cumulative non-colectomy rates, whereas concomitant immunomodulators was a significant prognostic factor for the higher remission rate. Gender (female) was a prognostic factor for higher remission rate at 1 year and higher cumulative non-colectomy rate. Conclusions: This study revealed good short- and long-term outcomes of IFX treatment in patients with steroid-refractory UC. Previous treatment with calcineurin inhibitors was a prognostic factor for poor outcomes of IFX treatment, whereas concomitant immunomodulators and gender (female) were prognostic factors for good outcomes.

P-059 Short-Term Outcomes of Adalimumab for Japanese Patients with Crohnʼs Disease and Associated Prognostic Factors

Background:In Japan, adalimumab has only been used to treat patients with Crohns disease (CD) for approximately 4 years. Therefore, the factors that determine the efficacy of adalimumab treatment in Japanese CD patients are unclear. Here, we evaluated the short-term outcomes of adalimumab for patients with CD and its associated prognostic factors. Methods:Retrospective data were collected from patients with luminal CD who received adalimumab treatment at some time between October 2010 to November 2014 at the IBD Center, Sapporo Kosei General Hospital. The initial Harvey–Bradshaw index (HBI) score of these subjects was ≥5; remission was defined as an HBI score of ⩽4 and complete remission (CR) was defined as an HBI score of ⩽4 with a normal C-reactive protein (CRP) level. The HBI score and CRP level were investigated at baseline and at 2, 4, 8, and 12 weeks following adalimumab administration. Missing data were imputed by the last observation carried forward method. The prognostic factors associated with the CR rate at 12 weeks were evaluated via univariate analysis. Further, we investigated the effect of previous treatment with infliximab on the CR rate at 12 weeks. Results:Of the 78 patients included in this study (mean age, 31.2 years), 28 were females. The mean duration of disease was 6.4 years. The mean CRP level and HBI score at baseline were 1.87 mg/dL and 8.1, respectively. Fifty-two patients had ileocolitis, 13 had ileitis, and 13 had colitis. In addition, 23 patients had stricturing disease, 4 had intra-abdominal fistulas, and 43 had perianal disease. Sixteen patients were smokers. Concomitant treatment with azathioprine or 6-mercaptopurine, 5-aminosalicylic acid, elemental diet therapy, and prednisolone was administered in 29, 64, 30, and 14 patients, respectively. Before initiating adalimumab therapy, 23 patients had had at least one intestinal resection, and 51 patients were naïve to infliximab. The respective HBI scores and CRP levels significantly decreased sequentially from baseline to 2, 4, 8, and 12 weeks as follows: from 8.1 and 1.87 mg/dL to 4.0 and 0.76 mg/dL, 3.1 and 0.54 mg/dL, 3.4 and 0.83 mg/dL, and 3.4 and 1.12 mg/dL. The remission and CR rates at 2, 4, 8, and 12 weeks were 64% and 35%, 80% and 59%, 73% and 56%, and 73% and 55%, respectively. Stricturing disease, intra-abdominal fistulas, previous bowel resection, and previous infliximab use significantly decreased the CR rate at 12 weeks. A significant 12-week CR rate was achieved in patients with greater disease duration and a higher baseline HBI score. The CR rate at 12 weeks was significantly higher in patients naïve to infliximab compared with those who had previously undergone infliximab therapy (73% versus 22%, P < 0.001); no significant prognostic factor associated to the CR rate at 12 weeks was identified in both groups. Conclusions:The efficacy of adalimumab treatment for Japanese patients with CD was demonstrated early, with CR rates of approximately 50%. Compared with patients with previous infliximab use, those who were naïve to infliximab achieved higher CR rates, regardless of their clinical characteristics.

Sa1207 Endoscopic Examination Is Necessary for Deciding to Discontinue Infliximab in Patients With Refractory Ulcerative Colitis Who Have Maintained Clinical Remission With Infliximab Maintenance Treatment

Background: Infliximab is typically administered to patients with inflammatory bowel disease (IBD) using a 2-hour infusion interval. Several studies have shown that shortened infusion intervals are well tolerated and are associated with increased patient satisfaction. The aim of this study was to determine long-term safety and efficacy of accelerated infliximab infusions in a cohort of IBD patients. Methods: A cohort of IBD patients on stable maintenance dosing of infliximab were offered accelerated infusions at our institution. Patients initially received infusions over a 90 minute interval, and if tolerated then continued with 60 minute infusions at each subsequent infusion. Patient demographics, number of accelerated infusions, and acute or delayed infusion reactions were recorded. Results: 44 patients with IBD (24 male, 8 ulcerative colitis) on stable infliximab dosing received accelerated infusions at our institution. A total of 652 accelerated infusions were administered. Median duration of accelerated infusions was 27 months (range 8-35 months). Mild acute infusion reactions were reported in 0.8% (5/652) and did not recur with return to 2 hour infusions. No severe infusion reactions were reported. No patients discontinued infliximab due to loss of response, although adjustments in infliximab dose or frequency occurred in 10 patients during the follow up period. Patient satisfaction with accelerated infusions was high (90%). Conclusion: Accelerated (60 minute) infliximab infusions were safe and well tolerated in our cohort of IBD patients. Accelerated infusions were associated with an acceptably low risk of infusion reaction and were not associated with a significant risk of loss of response over a median of 27 months of follow up. Patient acceptance of accelerated infliximab infusions was high and is consistent with results from prior studies.

Mo1168 Mesenchymal Stem Cells Partially Cancel Azoxymethane-Induced Tumor Initiation

Background: Western-style diet (WD) is known to be associated with insulin resistance and colonic inflammation which contributes to carcinogenesis. Biguanide metformin (M) and probiotics VSL#3 (V) can reduce insulin resistance and intestinal inflammation to inhibit tumor growth. We investigated the chemopreventive effect and the mechanism of the agents in WD-induced colitis associated carcinogenesis Methods: Male BALB/c mice were fed a control diet (CD) or WD for 8 weeks and WD groups were divided into groups of no treatment, M alone, V alone and combination therapy (CT). They were exposed to azoxymethane (AOM, 10mg/kg) and followed by 2 % dextran sodium sulfate (DSS) for 7 days. Tumor mass area was measured and tumor nodules were counted in colon of sacrificed mice. Disease activity index (DAI) was checked for 7 days during DSS exposure. Plasma glucose and insulin levels were measured and F4/80, Ki-67, claudin-1 and AMPK expressions were evaluated. Results: Tumor mass area and number of tumor nodules (.4 mm) were significantly decreased in CT group compared with WD group (p,0.01, p=0.016, respectively) and CT group showed low Ki-67 proliferation index (p,0.01). Plasma insulin and glucose levels in treatment groups (M, V, and CT group) were lower than those in WD group. CT group revealed low scores of DAI and decreased F4/80 positive cells accumulation during colitis compared with WD group (p=0.03, p,0.05, respectively). CT group showed maintained epithelial integrity by claudin-1 expression and increased AMPK activation. Conclusions: These results provide that combination therapy with metformin and VSL#3 attenuates tumor growth in WD induced colitic cancer model, which suggest that the treatment strategy could be useful in chemoprevention of colon cancer. The possible mechanisms were AMPK activation and inhibiting macrophage infiltration by maintaining epithelial integrity during colitis. Key word: colitic cancer, chemoprevention, metformin, VSL#3, western-style diet