Kentaro Yamashita

Enhancing epithelial engraftment of rat mesenchymal stem cells restores epithelial barrier integrity.

The cellular origin, in vivo function and fate of donor bone marrow‐derived cells residing in the recipient intestinal epithelial cells, pericryptal myofibroblasts or endothelial cells remain obscure. Although ‘immunoprivileged’ mesenchymal stem cells (MSCs) are prime candidates for cell‐ and gene‐based therapy, their precise role in colitis remains largely undetermined. Using a dextran sulphate sodium (DSS) colitis with busulphan (BU)‐induced hypoplastic marrow model, we examined the therapeutic effects of MSC transplantation, focusing on the role of MSCs as both cell providers and immunomodulators. Donor‐derived MSCs were detected by eGFP immunofluorescence and fluorescence in situ hybridization for Y‐chromosome (Y‐FISH) analysis. Western blot analysis of apical‐most tight junction proteins was performed with antibodies against claudin‐2, ‐7, ‐8, ‐12, ‐13, ‐15 and ZO‐1. Cytokine and cell cycle profiles were analysed by semi‐quantitative RT‐PCR and flow cytometry. Susceptibility to DSS colitis was significantly increased by co‐existing BU‐induced bone marrow hypoplasia and this increase was significantly reduced by enhancing epithelial engraftment of MSCs, an effect depending on restoring epithelial barrier integrity rather than inhibiting host immune responses. We provide evidence that implicates MSCs in maintaining epithelial barrier function by reassembling apical‐most tight junction proteins, claudins. The therapeutic efficacy of extrinsic MSCs depends on enhancing epithelial engraftment in damaged crypts by busulphan conditioning. Such a role for the MSC‐derived intestinal cells in colitis therapy merits further examination and may offer a promising new treatment for inflammatory bowel disease (IBD). Copyright

Phase I/II study of docetaxel/cisplatin/fluorouracil combination chemotherapy against metastatic esophageal squamous cell carcinoma.

Introduction: More effective regimens are urgently needed for squamous cell carcinoma of esophagus (SCCE), therefore, we conducted a phase I/II trial of a combination of docetaxel, platinum, and fluorouracil (TPF) for treating metastatic SCCE. Methods: This phase I/II trial (n = 12/39) was conducted in our institute from April 2005 to June 2008. Progression-free survival (PFS) and overall survival were analyzed by the Kaplan-Meier method. Results: The recommended dose of docetaxel was determined to be 50 mg/m2 in phase I. In phase II with a mean follow-up period of 13.3 months, the objective response rate was 66.6%, a median survival period of 13 months and PFS of 7 months was achieved, and the 1-year survival and PFS rates were 52.9% and 19.6%, respectively. Grade 3/4 toxicities of leukopenia, neutropenia, and anorexia were observed in 53.8%, 43.6%, and 25.6%, respectively. Conclusions: A TPF regimen against metastatic SCCE was well tolerated and achieved a favorable objective response rate and survival benefit compared with other recently reported regimens. Randomized phase III trials of the TPF regimen are warranted and urgently required.

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.

Myogenic lineage differentiated mesenchymal stem cells enhance recovery from dextran sulfate sodium-induced colitis in the rat

BackgroundAlthough mounting evidence implicates mesenchymal stem cells (MSCs) in intestinal tissue repair, uncertainty remains concerning the distribution, function, and fate of repopulating MSCs in recipient colonic tissues. Therefore, we investigated the role of transplanted MSCs in the repair phase of DSS colitis.MethodsLacZ-labeled rat MSCs were transplanted into rats with colitis induced by 4% DSS on day 2. Regular water replaced the DSS solution on day 6. Therapeutic effect was evaluated on day 9 by clinicopathologic and growth factor/cytokine expression profiles. We analyzed the Notch signaling pathway by Western blotting and characterized immunofluorescence of lacZ-labeled MSCs with confocal laser microscopy. In vivo differentiation of MSC was confirmed by transmission electron microscopy (TEM).ResultsRecovery of colitis was modestly but significantly promoted by MSC transplantation due to proceeding cell cycle and inhibiting apoptosis in the epithelia. Tgfa mRNA expression increased significantly, while Notch signaling was inhibited in the colonic tissues with MSC transplantation. β-Galactosidase-positive cells, which expressed α-SMA, desmin, and vimentin, were infrequently detected in the lamina propria stroma. DSS exposure in vitro proved to be the most potent inducer for α-SMA in MSCs where TEM demonstrated myogenic lineage differentiation.ConclusionsWe found that MSCs transplantation modestly promoted the repair of DSS colitis. The donor-derived MSCs were likely reprogrammed to differentiate to myogenic lineage cells by cues from the micro milieu. Further characterization of these cells is warranted as a basis for applying cell-based therapy for inflammatory bowel disease.

Development of transient thyroid disease and reaction during treatment of chronic hepatitis C with interferon

Six of 50 (12%) patients with chronic hepatitis C who were treated with interferon developed thyroid disease or an autoimmune thyroid reaction while undergoing treatment. One patient developed silent thyroiditis, with an increase in serum tri-iodothyronine (T3), thyroxine (T4), free T3, free T4, and markedly suppressed thyroid-stimulating hormone (TSH) levels, accompanied by the appearance of both antithyroglobulin (TgAb) and antimicrosomal antibodies (McAb). One patient developed hypothyroidism in association with moderately elevated TSH levels and high titers of McAb. TSH, TgAb, and McAb levels returned to the initial values at least 4 months after the end of interferon treatment (9 months of follow up). Four patients whose TgAb and/or McAb levels were elevated during treatment with interferon had been diagnosed as having subclinical autoimmune thyroiditis; however, their thyroid function remained in the normal range. These results suggested that treatment with interferon can cause a transient autoimmune thyroid reaction and disease as a side effect.

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

Characteristics of Japanese inflammatory bowel disease susceptibility loci

BackgroundThere are substantial differences in inflammatory bowel disease (IBD) genetics depending on the populations examined. We aimed to identify Japanese population-specific or true culprit susceptibility genes through a meta-analysis of past genetic studies of Japanese IBD.MethodsFor this study, we reviewed 2,703 articles. The review process consisted of three screening stages: we initially searched for relevant studies and then relevant single nucleotide polymorphisms (SNPs). Finally, we adjusted them for the meta-analysis. To maximize our chances of analysis, we introduced proxy SNPs during the first stage. To minimize publication bias, no significant SNPs and solitary SNPs without pairs were combined to be reconsidered during the third stage. Additionally, two SNPs were newly genotyped. Finally, we conducted a meta-analysis of 37 published studies in 50 SNPs located at 22 loci corresponding to the total number of 4,853 Crohn’s disease (CD), 5,612 ulcerative colitis (UC) patients, and 14,239 healthy controls.ResultsWe confirmed that the NKX2–3 polymorphism is associated with common susceptibility to IBD and that HLA-DRB1*0450 alleles increase susceptibility to CD but reduce risk for UC while HLA-DRB1*1502 alleles increase susceptibility to UC but reduce CD risk. Moreover, we found individual disease risk loci: TNFSF15 and TNFα to CD and HLA-B*5201, and NFKBIL1 to UC. The genetic risk of HLA was substantially high (odds ratios ranged from 1.54 to 2.69) while that of common susceptibility loci to IBD was modest (odds ratio ranged from 1.13 to 1.24).ConclusionsResults indicate that Japanese IBD susceptibility loci identified by the meta-analysis are closely associated with the HLA regions.

Genetic Variants in Surfactant, Pulmonary associated Protein D (SFTPD) and Japanese Susceptibility to Ulcerative Colitis

Background: Identifying culprit genes for a complex trait in a homogeneous population such as the Japanese remains challenging. We aimed to use previous achievements of genome‐wide association studies to identify precise susceptibility loci for inflammatory bowel disease in Japanese people and to simultaneously investigate the replication of recently identified susceptibility loci. Methods: An unrelated Japanese population of 174 Crohns disease patients, 296 ulcerative colitis (UC) patients, and 394 healthy controls was consecutively enrolled in this study. Genotype and haplotype analyses focusing on susceptibility to inflammatory bowel disease were performed using 7 single nucleotide polymorphisms (SNPs) including 5 HapMap tag SNPs within surfactant, pulmonary‐associated protein D (SFTPD) along with the 2 Caucasian susceptibility loci. We performed fine‐scale mapping of trait‐associated loci with the extension of a shattered coalescent process in a Bayesian framework. Epistasis on disease phenotypes was statistically explored with the interaction dendrogram. Results: A minor allele G of rs911887 reached statistical significance for susceptibility to UC. The 2‐allele haplotype GG comprising rs911887 and rs2243639 (Ala160Thr) within SFTPD was significantly associated with susceptibility to UC. A posterior density plot shows that trait‐associated variants in the vicinity of rs911887 are likely to exist. An association between NKX2‐3 and UC susceptibility was replicated and diverse evidence of epistasis in Japan was suggested. Conclusions: This preliminary study suggests that SFTPD is both a susceptibility gene and a disease‐modifying gene for UC in Japanese. Replication of the causality and functional analyses of SFTPD is urgently warranted. (Inflamm Bowel Dis 2009;)

Histological findings in asymptomatic hepatitis C virus carriers

There is controversy about clinical management of individuals who persistently have hepatitis C virus antibodies (HCVAb) but who have no symptoms or signs of liver disease. Liver biopsy samples were taken from 15 individuals, all of whom had normal alanine aminotransferase (ALT) levels, to determine the prevalence of liver disease and whether HCVAb and HCV‐RNA correlate with histological findings. Eleven patients with hepatitis C viremia had histological evidence of chronic hepatitis on biopsy. On the other hand, four HCV‐RNA‐negative individuals had almost normal liver histology. These findings indicate that serum HCV‐RNA is a sensitive and specific marker of liver disease in HCVAb‐positive subjects, independent of ALT levels. Furthermore, these results suggest that there are very few histologically healthy carriers of HCV among HCV‐RNA‐positive individuals.

Hepatic infarction with portal thrombosis

A case of hepatic infarction with portal thrombosis is reported. A 63-year-old woman with liver cirrhosis and esophageal varices was admitted for treatment of the esophagel varices. Endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy (EIS) were performed. Two months later, she experienced right hypochondralgia and right flank pain. Serum transaminase levels were suddenly elevated, and computed tomography scans of the liver showed multiple small nodular lesions. Her condition worsened, and she died of hepatic failure. Autopsy revealed splenic and portal vein thrombosis, multiple hepatic infarction, and evidence of chronic pancreatitis. We believe that liver cirrhosis and chronic pancreatitis were the main risk factors for the portal thrombosis, and the treatment for esophageal varices appeared to have triggered the thrombosis. The hepatic infarction was caused by the portal thrombosis.