Allogenic multilayered fibroblast sheets promote anastomotic site healing in a rat model of esophageal reconstruction.

OBJECTIVE: Anastomotic leakage is a common and severe complication of esophageal reconstruction. Accordingly, there is a clinical need for novel methods to prevent it. We developed multilayered, growth factor-secreting fibroblast sheets that promote wound healing and angiogenesis. The present study aimed to assess the utility of allogenic multilayered fibroblast sheets in preventing esophageal anastomotic leakage in a rat model of esophageal reconstruction. METHODS: Allogenic multilayered fibroblast sheets prepared from oral mucosal tissues were implanted at esophageal anastomotic sites. RESULTS: The allogenic multilayered fibroblast sheet group had significantly higher burst pressure and collagen deposition compared to a control group five days postoperatively. The expression levels of collagen type I and III mRNAs around esophageal suture sites were higher in the allogenic multilayered fibroblast sheet group compared to the control group on postoperative days 0, 3, and 5. There was a trend toward lower anastomotic leakage and lower abscess scores in the allogenic multilayered fibroblast sheet group compared to the control group; however, these differences did not reach statistical significance. Allogenic multilayered fibroblast sheets completely disappeared at ten days after implantation. Further, no inflammation was observed at suture sites with implanted allogenic multilayered fibroblast sheets at five days after surgery. CONCLUSION: Allogenic multilayered fibroblast sheets may represent a promising method of preventing esophageal anastomotic leakage.

Histological characteristics of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in asthmatic murine model during A(H1N1)pdm09 infection.

Pandemic influenza virus A(H1N1)pdm09 infection occurred in healthy children and young adults, but asthmatic patients presented more rapid progression of respiratory distress and plastic bronchitis. To investigate the pathogenesis of worsening respiratory symptoms after A(H1N1)pdm09 infection, we focused on matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum from mice with and without asthma were evaluated after A(H1N1)pdm09 or seasonal A(H1N1) infection. MMP-9 levels were more elevated in Asthma/A(H1N1)pdm09-infected mice than in non-Asthma/A(H1N1)pdm09-infected mice on both 3 and 7 days post-infection. Immunohistochemical findings in this pneumonia model showed that MMP-9 and TIMP-1 positive cells were observed in blood vessels and bronchus of lung tissue in severe pathological findings of pneumonia with asthma. Microscopically, shedding cells and secretions were conspicuous in the trachea on days 3 and 7 post-infection, in the A(H1N1)pdm09-infected mice with asthma. Our results suggest that MMP-9 and TIMP-1 expressions are related to severe pneumonia in the A(H1N1)pdm09 infection with asthma, leading to cause epithelial cell shedding.

Dry preserved multilayered fibroblast cell sheets are a new manageable tool for regenerative medicine to promote wound healing.

This study investigated the therapeutic effects of dry-preserved multi-layered fibroblast cell sheets (dry sheets) on cutaneous ulcers. Dry sheets were prepared by air-drying multi-layered fibroblast cell sheets (living sheets) to cease their life activities. Before in vivo application, we tested the release of growth factors into the medium to examine the mechanisms of dry sheets in wound healing. Vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) were released from both dry and living sheets, while high levels of fibroblast growth factor-2 (FGF-2) and high mobility group box 1 (HMGB1) protein were only from dry sheets. An in vitro fibroblast proliferation assay revealed that the dry sheet eluate significantly enhanced cell proliferation and VEGF and HGF production compared with living sheet eluate. FGF-2-neutralizing antibodies significantly blocked this proliferative response. In wounds created on diabetic mice, the dry sheet-treatment groups using autologous or allogeneic cells showed significantly accelerated wound closure compared with that in the no-treatment group. The storage stability of the dry sheet was better at refrigeration temperature than at room temperature and remained stable for at least 4 weeks. Our data indicated that allogeneic dry sheets represent a promising new tool for regenerative medicine that promotes wound healing.

Enhanced airway hyperresponsiveness in asthmatic children and mice with A(H1N1)pdm09 infection.

BACKGROUND: Severe asthma exacerbation is an important comorbidity of the 2009 HIN1 pandemic (A(H1N1)pdm09) in asthmatic patients. However, the mechanisms underlying severe asthma exacerbation remain unknown. In this study, airway hyperresponsiveness (AHR) was measured in pediatric asthma patients infected with A(H1N1)pdm09. We also evaluated AHR in asthmatic mice with A(H1N1)pdm09 infection and those with seasonal influenza for comparison. METHODS: AHRs in asthmatic children were defined as the provocative acetylcholine concentration causing a 20% reduction in forced expiratory volume in 1 s (PC20 ). To investigate the pathophysiology using animal models, BALB/c mice aged 6-8 weeks were sensitized and challenged with ovalbumin. Either mouse-adapted A(H1N1)pdm09, seasonal H1N1 virus (1 × 105 pfu/20 µl), or mock treatment as a control was administered intranasally. At 3, 7, and 10 days after infection, each group of mice was evaluated for AHR by methacholine challenge using an animal ventilator, flexiVent. Lung samples were resected and observed using light microscopy to assess the degree of airway inflammation. RESULTS: AHRs in the children with bronchial asthma were temporarily increased, and alleviated by 3 months after discharge. AHR was significantly enhanced in A(H1N1)pdm09-infected asthmatic mice compared to that in seasonal H1N1-infected mice (p < .001), peaking at 7 days postinfection and then becoming similar to control levels by 10 days postinfection. Histopathological examination of lung tissues showed more intense infiltration of inflammatory cells and severe tissue destruction in A(H1N1)pdm09-infected mice at 7 days postinfection than at 10 days postinfection. CONCLUSION: Our results suggest that enhanced AHR could contribute to severe exacerbation in human asthmatic patients with A(H1N1)pdm09 infection.

Risk for lymph node metastasis in Epstein-Barr virus-associated gastric carcinoma with submucosal invasion.

OBJECTIVES: Epstein-Barr virus-associated gastric cancer (EBVGC) has been reported to be associated with a low risk for lymph node metastasis (LNM). However, the curative criteria for endoscopic submucosal dissection (ESD) for submucosal EBVGC (pT1b-EBVGC) remain unclear. Our study aimed to investigate the risk factors for LNM in pT1b-EBVGC. METHODS: This was a retrospective multicenter study at five institutes in Japan. We reviewed medical records and extracted all pT1b-EBVGC cases that met the following criteria: (i) histologically proven submucosal gastric cancer; (ii) surgical or endoscopic resection between January 2000 and December 2016; and (iii) presence of Epstein-Barr virus (EBV) in tumor cells verified by EBV-encoded small RNA in situ hybridization (EBER-ISH). The association between clinicopathological factors and LNM were assessed using multivariable logistic regression analysis. RESULTS: A total of 185 pT1b-EBVGC cases were included in the analysis. LNM was found in nine cases (4.9%). Multivariable logistic regression analysis demonstrated that lymphatic invasion (OR 9.1; 95% CI 2.1-46.1) and submucosal invasion ≥4000 µm (OR 9.2; 95% CI 1.3-110.3) were significant risk factors for LNM. When we focused on pT1b-EBVGC without lymphatic invasion and with submucosal invasion <2000 µm, the rate of LNM was 0% (0/96, 95% CI 0-3.8%). CONCLUSIONS: Our findings indicated that lymphatic invasion and submucosal invasion ≥4000 µm were significant risk factors for LNM. ESD could be an appropriate option for pT1b-EBVGC without lymphatic invasion and with submucosal invasion <2000 µm.

Cathepsin B is highly expressed in pancreatic cancer stem-like cells and is associated with patients' surgical outcomes.

Cancer stem-like cells (CSLCs) in solid tumors are resistant to conventional chemotherapy and molecularly targeted therapy, which is thought to contribute to cancer recurrence and metastasis. The present study aimed to identify biomarkers for pancreatic CSLCs (P-CSLCs). Using our previously reported methods, P-CSLC-enriched populations were generated from pancreatic cancer cell lines. The protein expression profiles of these populations were compared with those of parental cells using two-dimensional electrophoresis, tandem mass spectrometry, flow cytometry and immunohistochemistry. Protein expression in surgical specimens was also evaluated for relationships with clinical outcomes. A lysosomal cysteine protease, cathepsin B (CTSB), was significantly upregulated in P-CSLCs compared with that in the parental cells, as shown using western blotting. Flow cytometry analysis also confirmed that CTSB was more highly expressed on the surface of P-CSLCs compared with that on parental cells. Moreover, PCLCs had elevated cellular secretions of CTSB compared with the parental cells. Finally, CTSB expression was evaluated in 69 resected tumor specimens, and high expression was associated with the patients' clinicopathological features and surgical outcomes. The present results suggested that CTSB is a biomarker for poor survival in patients with pancreatic cancer, which is possibly associated with P-CSLCs. This novel biomarker may also have potential as a therapeutic target.

Abnormal nuclear morphology is independent of longevity in a zmpste24-deficient fish model of Hutchinson-Gilford progeria syndrome (HGPS).

Lamin is an intermediate protein underlying the nuclear envelope and it plays a key role in maintaining the integrity of the nucleus. A defect in the processing of its precursor by a metalloprotease, ZMPSTE24, results in the accumulation of farnesylated prelamin in the nucleus and causes various diseases, including Hutchinson-Gilford progeria syndrome (HGPS). However, the role of lamin processing is unclear in fish species. Here, we generated zmpste24-deficient medaka and evaluated their phenotype. Unlike humans and mice, homozygous mutants did not show growth defects or lifespan shortening, despite lamin precursor accumulation. Gonadosomatic indices, blood glucose levels, and regenerative capacity of fins were similar in 1-year-old mutants and their wild-type (WT) siblings. Histological examination showed that the muscles, subcutaneous fat tissues, and gonads were normal in the mutants at the age of 1 year. However, the mutants showed hypersensitivity to X-ray irradiation, although p53target genes, p21 and mdm2, were induced 6 h after irradiation. Immunostaining of primary cultured cells from caudal fins and visualization of nuclei using H2B-GFP fusion proteins revealed an abnormal nuclear shape in the mutants both in vitro and in vivo. The telomere lengths were significantly shorter in the mutants compared to WT. Taken together, these results suggest that zmpste24-deficient medaka phenocopied HGPS only partially and that abnormal nuclear morphology and lifespan shortening are two independent events in vertebrates.

Expression levels of UL16 binding protein 1 and natural killer group 2 member D affect overall survival in patients with gastric cancer following gastrectomy.

UL16 binding protein 1 (ULBP1) expressed on the tumor cell surface binds to the natural killer group 2 member D (NKG2D) receptor presenting on natural killer (NK), cluster of differentiation (CD)8+ T, and γ δ T cells. However, the roles of ULBP1 and NKG2D expression and associated immune responses in gastric cancer are unclear. The present study investigated the associations between ULBP1 and NKG2D expression and clinical outcomes in patients with gastric cancer. The levels of ULBP1 and NKG2D expression were examined in human gastric cancer cell lines and gastric cancer tissues from 98 patients who underwent surgery from 2004 to 2008. MKN-74 cells expressed ULBP1 with ULBP2, -5, or -6. NKG2D was expressed at a higher level following activation of T cells and NK cells. Among the tissue sections positive for NKG2D expression, 6 patients were positive for CD8 and CD56. In all tissues, NKG2D-expressing cells were typically aCD8+ T cells. Patients with NKG2D expression in tumors exhibited significantly longer overall survival (OS) compared with patients without NKG2D expression in tumors (P=0.0217). The longest OS was observed in patients positive for ULBP1 and NKG2D, whereas the shortest OS was observed in patients negative for ULBP1 and NKG2D. The interaction between ULBP1 and NKG2D may improve OS in patients with gastric cancer, and may have applications in immunotherapy for the induction of adaptive immunity in patients with cancer. Additionally, ULBP1 and NKG2D may be useful as prognostic biomarkers in gastric cancer.

High secreted protein acidic and rich in cysteine expression in peritumoral fibroblasts predicts better prognosis in patients with resectable gastric cancer.

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein that may serve an important role in epithelial-mesenchymal transition. Recent studies have demonstrated that SPARC status is a prognostic indicator in various cancer types; however, its value remains unclear in gastric cancer (GC). In the present study, the localization and prognostic impact of SPARC expression were evaluated in patients with GC. Immunohistochemical analysis of SPARC expression was performed in 117 surgically resected GC specimens, and the localization of SPARC positive cells, as well as the rassociation between SPARC expression and clinicopathological characteristics were evaluated. High SPARC expression was observed in 47 cases; the glycoprotein was localized in the peritumoral fibroblasts, but was rarely observed in the cytoplasm of cancer cells. Heterogeneity of SPARC expression was observed in 52 cases. High stromal SPARC expression was identified to be an independent predictor of more favorable prognosis (overall survival and recurrence free survival) in all patients (P<0.001). On subgroup analysis, this association remained significant in patients who received adjuvant chemotherapy, but not in patients who did not (P<0.001). Stromal SPARC expression predicts better prognosis in GC patients who underwent curative resection; this appears to be associated with improved response to chemotherapy.

Pulmonary inflammation and cytokine dynamics of bronchoalveolar lavage fluid from a mouse model of bronchial asthma during A(H1N1)pdm09 influenza infection.

Asthmatic patients present more rapid progression of respiratory distress after A(H1N1)pdm09 influenza infection than after seasonal infection. Here, we sought to clarify the pathophysiology of early deterioration in asthmatic patients after A(H1N1)pdm09 infection. Cytokine levels and virus titres in bronchoalveolar lavage fluid from mice with and without asthma after A(H1N1)pdm09 or seasonal H1N1 infection were examined. In asthma/A(H1N1)pdm09 mice, IL-6 and TNF-α levels peaked at 3 days post-infection and were higher than those in all other groups. IFN-γ levels in asthma/A(H1N1)pdm09 mice at 3 days post-infection were higher than in all other mice at any time point, whereas at 7 days post-infection, the levels were lowest in asthma/A(H1N1)pdm09 mice. Virus titres in asthma/A(H1N1)pdm09 mice were highest at 3 days post-infection, and decreased by 7 days post-infection, although the levels at this time point were still higher than that in any other group. Histopathological examination showed more inflammatory cell infiltration and lung tissue destruction in the asthma/A(H1N1)pdm09 group than in any other group. The distinct cytokine profiles in A(H1N1)pdm09-infected asthmatic mice indicated excessive inflammation and virus replication within a few days after infection. Thus, bronchial asthma could be a more exacerbating factor for pandemic influenza infection than for seasonal influenza infection.

Development of Novel Mouse Model of Ulcers Induced by Implantation of Magnets.

We developed a novel mouse model of human refractory cutaneous ulcers that more faithfully reflects pathology and evaluated the effects of mixed cell sheets comprising peripheral blood mononuclear cells and fibroblasts, which we previously developed for treating refractory cutaneous ulcers. Model development involved sandwiching the skin between two magnets, one of which was implanted under the skin for 7 consecutive days. This magnet-implanted ulcer model produced persistently large amounts of exudate and induced the infiltration of the ulcer with inflammatory cells. The model mice had a thicker epidermis and impaired transforming growth factor-ß (TGF-ß) signaling followed by SMAD2 down-regulation, which causes epidermal hyperplasia in chronic ulcers. Impaired TGF-ß signaling also occurred in the ulcers of critical limb ischemia patients. Mixed cell implantation in this ulcer model reduced TNF-α and IL-6 levels in the tissues surrounding the mixed cell sheet-treated ulcers compared with controls or mice treated with trafermin (FGF2). Seven days after commencing therapy, the epidermis was thinner in mice treated with the mixed cell sheets than in controls. This model may therefore serve as a clinically relevant model of human ulcers, and our mixed cell sheets may effectively relieve chronic inflammation and inhibit refractoriness mechanisms.

Ulcer healing effect of autologous mixed sheets consisting of fibroblasts and peripheral blood mononuclear cells in rabbit ischemic hind limb.

We developed mixed cell sheets consisting of fibroblasts and peripheral blood mononuclear cells that had high potency for secreting vascular endothelial growth factor. The purpose of this study was to confirm the therapeutic effects of mixed sheets in rabbits suffering from ulcers at the ischemic hind limbs. We used the ulcer model, which was constructed by implantation and sandwiching the skin between two magnets to be a representative of human refractory cutaneous ulcer. The ulcer healing rate of mixed cell sheets was higher than that of the control at an early stage of healing. The calf blood pressure and angiographic score, which were considered to reflect rough collateral blood flow, did not vary amongmixed cell sheets. However, through laser Doppler perfusion image, implantation of mixed cell sheets revealed a significant improvement in microvascular blood flow in the healed skin of the ischemic limb compared to trafermin, a recombinant human basic fibroblast growth factor, and the control. These results suggest that mixed cell may operate predominantly on the surface of the ischemic tissue by their angiogenic potency, thereby promoting healing of the ischemic ulcer. Mixed cell sheets could become a promising therapeutic material for refractory cutaneous ulcers.

Distinct Distribution of Immunocytes in a Retropharyngeal Lymphadenopathy Associated with Kawasaki Disease: A Case Study Compared with Tonsillitis.

OBJECTIVES: Retropharyngeal lesions are often associated with Kawasaki disease (KD). A 4-year-old male first presented a peritonsillar and retropharyngeal abscess-like lesion. Surgical tonsillectomy was performed to avoid a risk of mediastinal abscess, but he fulfilled the diagnostic criteria of KD after the operation. This prompted us to perform a histological study on the KD tonsils. METHODS: The histopathology of the KD tonsil specimens were compared with hypertrophic tonsils obtained from 4 patients with chronic tonsillitis unrelated to KD assessed by the immunostainings. RESULTS: KD tonsils showed small lymphatic follicles and neutrophil infiltration in the peritonsillar muscle layer, with no evidence of vasculitis or abscess formation. The KD tonsils exclusively showed (1) predominant activated CD4+ T cells in the perifollicular interstitium, (2) sparse scattering of CD68+ monocytes/macrophages in the lymphatic follicles, and (3) polyclonal carcinoembryonic antigen-positive cells in the lymphatic follicles and venules with the high endothelial cells. CONCLUSIONS: The uniquely distributed immunocytes suggest the inflammatory process of KD involving the pathogen-associated molecules.

Calreticulin is highly expressed in pancreatic cancer stem-like cells.

Cancer stem-like cells (CSLCs) in solid tumors are thought to be resistant to conventional chemotherapy or molecular targeting therapy and to contribute to cancer recurrence and metastasis. In this study, we aimed to identify a biomarker of pancreatic CSLCs (P-CSLCs). A P-CSLC-enriched population was generated from pancreatic cancer cell lines using our previously reported method and its protein expression profile was compared with that of parental cells by 2-D electrophoresis and tandem mass spectrometry. The results indicated that a chaperone protein calreticulin (CRT) was significantly upregulated in P-CSLCs compared to parental cells. Flow cytometry analysis indicated that CRT was mostly localized to the surface of P-CSLCs and did not correlate with the levels of CD44v9, another P-CSLC biomarker. Furthermore, the side population in the CRThigh /CD44v9low population was much higher than that in the CRTlow /CD44v9high population. Calreticulin expression was also assessed by immunohistochemistry in pancreatic cancer tissues (n = 80) obtained after radical resection and was found to be associated with patients' clinicopathological features and disease outcomes in the Cox proportional hazard regression model. Multivariate analysis identified CRT as an independent prognostic factor for pancreatic cancer patients, along with age and postoperative therapy. Our results suggest that CRT can serve as a biomarker of P-CSLCs and a prognostic factor associated with poorer survival of pancreatic cancer patients. This novel biomarker can be considered as a therapeutic target for cancer immunotherapy.

In vivo 3D analysis of systemic effects after local heavy-ion beam irradiation in an animal model.

Radiotherapy is widely used in cancer treatment. In addition to inducing effects in the irradiated area, irradiation may induce effects on tissues close to and distant from the irradiated area. Japanese medaka, Oryzias latipes, is a small teleost fish and a model organism for evaluating the environmental effects of radiation. In this study, we applied low-energy carbon-ion (26.7 MeV/u) irradiation to adult medaka to a depth of approximately 2.2 mm from the body surface using an irradiation system at the National Institutes for Quantum and Radiological Science and Technology. We histologically evaluated the systemic alterations induced by irradiation using serial sections of the whole body, and conducted a heart rate analysis. Tissues from the irradiated side showed signs of serious injury that corresponded with the radiation dose. A 3D reconstruction analysis of the kidney sections showed reductions in the kidney volume and blood cell mass along the irradiated area, reflecting the precise localization of the injuries caused by carbon-beam irradiation. Capillary aneurysms were observed in the gill in both ventrally and dorsally irradiated fish, suggesting systemic irradiation effects. The present study provides an in vivo model for further investigation of the effects of irradiation beyond the locally irradiated area.

BUBR1 overexpression predicts disease-specific survival after nephroureterectomy in patients with upper tract urothelial carcinoma.

OBJECTIVE: To date, there are few reliable markers to distinguish tumors with aggressive characteristics in upper tract urothelial carcinoma. The purpose of this study was to identify a biomarker related to genetic instability (chromosomal instability or microsatellite instability) with prognostic value, in patients with upper tract urothelial carcinoma. METHODS: Expression of chromosomal instability-related markers (BUBR1, p53, polo-like kinase 1) and microsatellite instability-related markers (mismatch repair proteins, MLH1 and MSH2) were assessed by immunohistochemistry in 100 patients who had radical nephroureterectomy for upper tract urothelial carcinoma. Numerical aberrations of chromosomes 7, 9 and 17 were evaluated by fluorescence in situ hybridization, which allowed an estimation of the degree of chromosomal instability. BUB1B copy number was examined by array-based comparative genomic hybridization in 32 patients with upper tract urothelial carcinoma. RESULTS: BUBR1 status was most significantly correlated with chromosomal instability-related and low mismatch repair parameters, according to the molecular biomarkers examined. Overexpression of BUBR1 is frequently detected in tumors with higher histological grade (P < 0.0001) and is significantly associated with chromosomal instability (P = 0.0071). Array-based comparative genomic hybridization revealed that no tumors (0%) showed BUB1B amplification and gain, indicating that overexpression of BUBR1 was independent of BUB1B copy number. For disease-specific survival, BUBR1 overexpression, lymphovascular invasion, pathological tumor stage, pathological lymph node involvement and low MSH2 expression were significant prognostic factors in univariate analyses. In multivariate analyses, BUBR1 overexpression was an independent prognostic factor for disease-specific survival (P = 0.0483, risk ratio 3.76, 95% confidence interval: 1.01-18.43). CONCLUSIONS: BUBR1 may have significant potential as a biomarker for estimating disease-specific survival in patients with upper tract urothelial carcinoma treated by radical nephroureterectomy.

Rituximab-associated progressive multifocal leukoencephalopathy derived from non-Hodgkin lymphoma: neuropathological findings and results of mefloquine treatment.

A 66-year-old man with non-Hodgkin lymphoma (NHL) developed progressive multifocal leukoencephalopathy (PML) after undergoing chemotherapy including rituximab. Although the administration of mefloquine at a dose of 500 mg weekly temporarily led to a dramatic decrease in the copy number of JC Virus DNA in the cerebrospinal fluid, the patient's symptoms gradually worsened. The CD4(+) T count remained continuously low, at least until approximately five months after the last cycle of chemotherapy. A postmortem examination performed 10 months after the onset of PML disclosed a severe condition associated with rituximab-treated PML originating from NHL and a high mefloquine concentration in the brain. The accumulation of further data regarding mefloquine treatment in PML cases may help to elucidate the optimal dosage and time window for effectively treating PML.

Proposal of intestinal tissue engineering combined with Bianchi's procedure.

AIM: The aim of this study is to examine the feasibility of the small intestinal submucosa (SIS) when the longitudinal staples during Bianchi's procedure are replaced with SIS graft. METHODS: The mesentery of the bowel was separated based on the bifurcated vessels in five beagles. A 2×7-cm longitudinal half of the bowel was excised and the defect was repaired using SIS with similar blood supply in Bianchi's operation. Six months later, intestinal motility in the SIS-grafted area was recorded. Tissue preparations were obtained from the reorganized area. An organ bath technique with electrical field stimulation was applied. Both the native small intestine and grafted area were morphologically investigated using immunohistochemistry. MAIN RESULTS: All dogs survived and thrived with no anastomotic leakage. Isoperistaltic migrating contractility during fasting was observed through the grafted segment including the reorganized area. The SIS-reorganized tissue contracted in response to an acetylcholine agonist and electrical field stimulation. The mucosa was covered with normal epithelium. Reorganization of neural and smooth muscle cells was observed. CONCLUSIONS: SIS has the potential for use as a scaffold that promotes the formation of a physical and physiological neointestine. Our present proposal approaches a novel surgical treatment in patients with short bowel syndrome.

Combination immunotherapy with 4-1BB activation and PD-1 blockade enhances antitumor efficacy in a mouse model of subcutaneous tumor.

BACKGROUND/AIM: The purpose of the present study was to establish an effective immunotherapy by skewing the cosignal balance to be on the positive side by using the combination of monoclonal antibody (mAb) against 4-1BB also known as Cluster of Differentiation (CD) 137 as a co-stimulatory effector and to programmed death-1 (PD-1) to blockade the immune checkpoint. MATERIALS AND METHODS: Mice implanted with 1×10(5) CT26 cells were treated with anti 4-1BB mAb alone, anti PD-1 mAb alone, or both anti 4-1BB mAb and anti PD-1 mAb. Immune cell populations were analyzed by flow cytometry. Tumor-infiltrating T-cells were evaluated by immunohistochemistry. RESULTS: Mice treated with the combination therapy had the best antitumor response that resulted in complete tumor rejection. The numbers of CD4(+) interferon (IFN)-γ(+) and CD8(+) IFN-γ(+) T-cells were significantly higher in the combination group. The number of tumor-infiltrating T-cells was significantly increased in the combination therapy. CONCLUSION: The therapeutic strategy of targeting co-signal molecules has promising clinical applications in the future.

Influence of mesenchymal stem cells on stomach tissue engineering using small intestinal submucosa.

Small intestinal submucosa (SIS) is a biodegradable collagen-rich matrix containing functional growth factors. We have previously reported encouraging outcomes for regeneration of an artificial defect in the rodent stomach using SIS grafts, although the muscular layer was diminutive. In this study, we investigated the feasibility of SIS in conjunction with mesenchymal stem cells (MSCs) for regeneration of the gastrointestinal tract. MSCs from the bone marrow of green fluorescence protein (GFP)-transgenic Sprague-Dawley (SD) rats were isolated and expanded ex vivo. A 1 cm whole-layer stomach defect in SD rats was repaired using: a plain SIS graft without MSCs (group 1, control); a plain SIS graft followed by intravenous injection of MSCs (group 2); a SIS graft co-cultured with MSCs (group 3); or a SIS sandwich containing an MSC sheet (group 4). Pharmacological, electrophysiological and immunohistochemical examination was performed to evaluate the regenerated stomach tissue. Contractility in response to a muscarinic receptor agonist, a nitric oxide precursor or electrical field stimulation was observed in all groups. SIS grafts seeded with MSCs (groups 3 and 4) appeared to support improved regeneration compared with SIS grafts not seeded with MSCs (groups 1 and 2), by enabling the development of well-structured smooth muscle layers of significantly increased length. GFP expression was detected in the regenerated interstitial tissue, with fibroblast-like cells in the seeded-SIS groups. SIS potently induced pharmacological and electrophysiological regeneration of the digestive tract, and seeded MSCs provided an enriched environment that supported tissue regeneration by the SIS graft in the engineered stomach.