[Annuloaortic Ectasia Associated with Single Coronary Artery and Ventricular Septal Defect;Report of a Case].

Single coronary artery is rear. Various combination anomalies have been reported in patients with this anomaly undergoing heart surgery. We report a case of annuloaortic ectasia combined with single coronary artery and ventricular septal defect. The patient was a 67-year-old man with exertional dyspnea. Coronary angiography and computed tomography revealed a single coronary artery. Aortography showed severe aortic regurgitation and dilatation of Valsalva sinus. Ultrasonic cardiography showed small ventricular septal defect at the membranous septum. He underwent Modified Bentall's operation. He recovered without any complications. An annuloaortic ectasia associated with single coronary and ventricular septal defect is a very rare combination.

A novel in vivo regulatory role of P-glycoprotein in alloimmunity.

P-glycoprotein (P-gp) is required for adaptive immunity through defined functions in T cell activation and antigen presenting cell (APC) maturation. The potential role of P-gp as an in vivo regulator of alloimmunity is currently unknown. Here we show that P-gp blockade prolongs graft survival in a murine heterotopic cardiac allotransplantation model through in vivo inhibition of the T helper 1 (Th1) cytokine IFN-gamma and the Th2 product IL-4, and via downregulation of the APC-expressed positive costimulatory molecule CD80. In vitro, the P-gp antagonist PSC833, a non-calcineurin-inhibitory cyclosporine A analogue, specifically inhibited cellular efflux of the P-gp substrate rhodamine-123 in wild-type CD3(+) T cells and MHC class II(+) APCs but not their P-gp knockout counterparts that lacked rhodamine-123 efflux capacity. Additionally, P-gp blockade significantly inhibited murine alloimmune T cell activation in a dose-dependent fashion. In vivo, P-gp blockade significantly prolonged graft survival in Balb/c recipients of C57BL/6 cardiac allografts from 8.5+/-0.5 to 11.7+/-0.5 days (P<0.01), similar in magnitude to the effects of monotherapy with cyclosporine A. Moreover, P-gp blockade, compared to controls, attenuated intragraft expression of CD3 and CD80, but not CD86, and inhibited IFN-gamma and IL-4 production (P<0.05). In the setting of systemic CD86 inhibition, P-gp blockade suppressed IFN-gamma and IL-4 production significantly further (to 98% and 89% inhibition, respectively) compared to either P-gp or anti-CD86 blockade alone, and markedly prolonged allograft survival compared to anti-CD86 blockade alone (40.5+/-4.6 versus 22.5+/-2.6 days, respectively, P<0.01). Our findings define a novel in vivo regulatory role of P-gp in alloimmunity and identify P-gp as a potential therapeutic target in allotransplantation.

Upregulation of the apoptosis-related inflammasome in cardiac allograft rejection.

BACKGROUND: Inflammation is a major factor in cardiac allograft rejection. Accumulating reports have demonstrated an important role of the inflammation-induced adaptor complex, called the inflammasome, in the field of immunology. The apoptosis-associated, speck-like protein containing a caspase recruitment domain (ASC) is an adaptor protein that forms the inflammasome and regulates caspase-1-dependent generation of inflammatory cytokines. The aim of the present study was to determine how ASC is associated with the development of cardiac allograft rejection. METHODS: We used a murine heterotopic cardiac transplantation model between fully incompatible strains. Donor hearts (n = 9 for each time-point) were harvested for examination on Days 1, 4, 7 and 12 after transplantation. Histopathologic findings of cardiac grafts were evaluated using rejection scores. The expression of ASC and inflammatory cytokines in cardiac grafts were analyzed by immunohistochemistry and real-time reverse transcript-polymerase chain reaction (RT-PCR). RESULTS: Expression levels of both ASC and IL-1 beta were higher in the myocardial interstitium of allografts in parallel to the progress of cardiac rejection during the acute phase after transplantation. In contrast, expression of ASC and IL-1 beta remained low in isografts. Cardiac allografts treated with tacrolimus showed decreased expression of both ASC and IL-1 beta similar to that seen in isografts. Real-time RT-PCR demonstrated similar alteration of ASC and IL-1 beta mRNA expression in cardiac grafts during the acute phase. CONCLUSIONS: Our results demonstrate a novel finding showing that upregulation of ASC is closely associated with the inflammation induced in cardiac grafts after transplantation in the mouse.

The emerging role of T cell Ig mucin 1 in alloimmune responses in an experimental mouse transplant model.

T cell Ig mucin 1 (TIM-1) plays an important role in regulating immune responses in autoimmune and asthma models, and it is expressed on both Th1 and Th2 cells. Using an antagonistic TIM-1-specific antibody, we studied the role of TIM-1 in alloimmunity. A short course of TIM-1-specific antibody monotherapy prolonged survival of fully MHC-mismatched vascularized mouse cardiac allografts. This prolongation was associated with inhibition of alloreactive Th1 responses and preservation of Th2 responses. TIM-1-specific antibody treatment was more effective in Th1-type cytokine-deficient Stat4(-/-) recipients as compared with Th2-type cytokine-deficient Stat6(-/-) recipients. Subtherapeutic doses of rapamycin plus TIM-1-specific antibody resulted in allograft acceptance and prevented the development of chronic allograft vasculopathy. Allograft survival via this treatment was accompanied by a Th1- to Th2-type cytokine switch. Depletion of natural Tregs abrogated the graft-protecting effect of the TIM-1-specific antibody. Importantly, CD4(+)CD25(+) Tregs obtained from long-term survivors had enhanced regulatory activity as compared with naive CD4(+)CD25(+) Tregs. Consistent with this, TIM-1-specific antibody treatment both preserved Tregs and prevented the expansion of alloreactive effector Th1 cells in an alloreactive TCR transgenic adoptive transfer model. These studies define previously unknown functions of TIM-1 in regulating alloimmune responses in vivo and may provide a novel approach to promoting transplantation tolerance.

Identification of cells initiating human melanomas.

Tumour-initiating cells capable of self-renewal and differentiation, which are responsible for tumour growth, have been identified in human haematological malignancies and solid cancers. If such minority populations are associated with tumour progression in human patients, specific targeting of tumour-initiating cells could be a strategy to eradicate cancers currently resistant to systemic therapy. Here we identify a subpopulation enriched for human malignant-melanoma-initiating cells (MMIC) defined by expression of the chemoresistance mediator ABCB5 (refs 7, 8) and show that specific targeting of this tumorigenic minority population inhibits tumour growth. ABCB5+ tumour cells detected in human melanoma patients show a primitive molecular phenotype and correlate with clinical melanoma progression. In serial human-to-mouse xenotransplantation experiments, ABCB5+ melanoma cells possess greater tumorigenic capacity than ABCB5- bulk populations and re-establish clinical tumour heterogeneity. In vivo genetic lineage tracking demonstrates a specific capacity of ABCB5+ subpopulations for self-renewal and differentiation, because ABCB5+ cancer cells generate both ABCB5+ and ABCB5- progeny, whereas ABCB5- tumour populations give rise, at lower rates, exclusively to ABCB5- cells. In an initial proof-of-principle analysis, designed to test the hypothesis that MMIC are also required for growth of established tumours, systemic administration of a monoclonal antibody directed at ABCB5, shown to be capable of inducing antibody-dependent cell-mediated cytotoxicity in ABCB5+ MMIC, exerted tumour-inhibitory effects. Identification of tumour-initiating cells with enhanced abundance in more advanced disease but susceptibility to specific targeting through a defining chemoresistance determinant has important implications for cancer therapy.

PDL1 is required for peripheral transplantation tolerance and protection from chronic allograft rejection.

The PD-1:PDL pathway plays an important role in regulating alloimmune responses but its role in transplantation tolerance is unknown. We investigated the role of PD-1:PDL costimulatory pathway in peripheral and a well established model of central transplantation tolerance. Early as well as delayed blockade of PDL1 but not PDL2 abrogated tolerance induced by CTLA4Ig in a fully MHC-mismatched cardiac allograft model. Accelerated rejection was associated with a significant increase in the frequency of IFN-gamma-producing alloreactive T cells and expansion of effector CD8(+) T cells in the periphery, and a decline in the percentage of Foxp3(+) graft infiltrating cells. Similarly, studies using PDL1/L2-deficient recipients confirmed the results with Ab blockade. Interestingly, while PDL1-deficient donor allografts were accepted by wild-type recipients treated with CTLA4Ig, the grafts developed severe chronic rejection and vasculopathy when compared with wild-type grafts. Finally, in a model of central tolerance induced by mixed allogeneic chimerism, engraftment was not abrogated by PDL1/L2 blockade. These novel data demonstrate the critical role of PDL1 for induction and maintenance of peripheral transplantation tolerance by its ability to alter the balance between pathogenic and regulatory T cells. Expression of PDL1 in donor tissue is critical for prevention of in situ graft pathology and chronic rejection.

Hepatocyte growth factor prevents pulmonary ischemia-reperfusion injury in mice.

BACKGROUND: Ischemia-reperfusion (IR) injury after lung transplantation leads to significant morbidity and mortality in recipients, which remains the major obstacle in clinical lung transplantation. To reduce pulmonary graft dysfunction and improve prognosis after lung transplantation, prevention of IR-induced lung injury in the peri-operative period is required. In the present study, we investigated the effects of recombinant hepatocyte growth factor (HGF) on pulmonary IR injury using a murine model system. METHODS: To assess the protective effect of HGF against lung injury, mice with pulmonary IR were divided into two groups and injected with 500 microg/kg of human recombinant HGF or the same dose of saline alone as a control. RESULTS: After pulmonary IR injury, the lung injury score increased in a time-dependent manner up to 24 hours. A significant reduction of lung injury score was observed with the administration of exogenous HGF. Moreover, the ratio of apoptotic cells was significantly reduced in mice treated with HGF. Significantly increased expression of Bcl-xL was observed after IR in mice administered HGF as compared with saline-treated controls. In contrast, expression of Bax was reduced significantly in HGF-treated mice. Serum levels of endogenous murine HGF were increased significantly in HGF-treated mice. CONCLUSIONS: Our findings indicate that administration of exogenous HGF ameliorates the pulmonary tissue injury induced by IR, which may provide an alternative for prevention of IR-induced lung injury in the peri-operative period in lung transplantation.

A novel alloantigen-specific CD8+PD1+ regulatory T cell induced by ICOS-B7h blockade in vivo.

Delayed ICOS-B7h signal blockade promotes significant prolongation of cardiac allograft survival in wild-type but not in CD8-deficient C57BL/6 recipients of fully MHC-mismatched BALB/c heart allografts, suggesting the possible generation of CD8(+) regulatory T cells in vivo. We now show that the administration of a blocking anti-ICOS mAb results in the generation of regulatory CD8(+) T cells. These cells can transfer protection and prolong the survival of donor-specific BALB/c, but not third party C3H, heart grafts in CD8-deficient C57BL/6 recipients. This is unique to ICOS-B7h blockade, because B7 blockade by CTLA4-Ig prolongs graft survival in CD8-deficient mice and does not result in the generation of regulatory CD8(+) T cells. Those cells localize to the graft, produce both IFN-gamma and IL-4 after allostimulation in vitro, prohibit the expansion of alloreactive CD4(+) T cells, and appear to mediate a Th2 switch of recipient CD4(+) T cells after adoptive transfer in vivo. Finally, these cells are not confined to the CD28-negative population but express programmed death 1, a molecule required for their regulatory function in vivo. CD8(+)PD1(+) T cells suppress alloreactive CD4(+) T cells but do not inhibit the functions by alloreactive CD8(+) T cells in vitro. These results describe a novel allospecific regulatory CD8(+)PD1(+) T cell induced by ICOS-B7h blockade in vivo.

Suppression of acute and chronic rejection by hepatocyte growth factor in a murine model of cardiac transplantation: induction of tolerance and prevention of cardiac allograft vasculopathy.

BACKGROUND: Although treatment with immunosuppressive agents has contributed to overcoming acute rejection and improving the midterm survival of transplanted hearts, cardiac allograft vasculopathy (CAV) has remained the main cause of primary graft failure. Recent approaches have shown that hepatocyte growth factor (HGF) exhibits cardiotrophic functions. We therefore addressed whether HGF would regulate acute and chronic rejection in cardiac transplantation. METHODS AND RESULTS: We used a murine heterotopic cardiac transplantation model between fully incompatible strains and administered 500 microg x kg(-1) x d(-1) HGF during the initial 14 days after transplantation. The HGF-treated allografts showed significantly prolonged survival (42.3+/-4.1 days, P<0.001) compared with the controls (11.1+/-0.6 days), with tolerance induction in 47.4%. Histopathologically, the number of infiltrating cells was significantly decreased and myocardial necrosis was less prominent with a reduction of apoptosis in the allografts by HGF treatment during acute rejection. In the long-term surviving allografts, HGF significantly inhibited the development of CAV and interstitial fibrosis. With respect to intragraft cytokine mRNA expression, HGF treatment reduced the early expression of interferon-gamma and enhanced the expression of transforming growth factor-beta1 during the acute phase and of interleukin-10 continuously through the acute phase to the chronic phase. CONCLUSIONS: Our findings demonstrate that HGF can prolong the survival of allografts by its cardioprotective and immunomodulative potencies. Thus, HGF administration may constitute a new therapeutic approach to preventing cardiac graft failure that has not been overcome by conventional immunosuppressive agents.

Stromal tumor of the pancreas with expression of c-kit protein: report of a case.

We report on a case of a stromal tumor, similar to a gastrointestinal stromal tumor, originating from the pancreas. The patient was a 54-year-old woman, who was seen at the Kofu Municipal Hospital because of an abdominal tumor. On abdominal computed tomography and splenic arteriography, the tumor was detected in the pancreatic tail. The patient underwent distal pancreatectomy with splenectomy. Macroscopically, the cut surface of the tumor showed almost completely surrounded by the normal pancreatic tissue. Microscopically, the tumor composed of spindle-shaped cells that were immunoreactive for vimentin, CD34, and c-kit protein. Therefore, the tumor was diagnosed as a stromal tumor of the pancreas. The expression of c-kit protein suggests that this pancreatic stromal tumor may originate from primitive mesenchymal cells which can be a logical candidate for the origin of gastrointestinal stromal tumors and extra-gastrointestinal stromal tumors.

Expression of matrix metalloproteinases in cardiac allograft vasculopathy and its attenuation by anti MMP-2 ribozyme gene transfection.

OBJECTIVE: Proliferation and migration of vascular smooth muscle cells (SMCs) causes intimal thickening during cardiac allograft vasculopathy (CAV). This process requires the degradation or remodeling of extracellular matrix (ECM) surrounding the cells. Imbalance between degradation and accumulation of ECM also contributes to the development of CAV. In this study, we investigated the contribution of matrix metalloprotenases (MMPs), enzymes regulating ECM turnover, to the development of CAV. METHODS: Donor hearts from male DBA mice were heterotopically transplanted to male B10.D2 recipient mice, and harvested at days 15 and 30 post transplantation. We examined expression MMP-2, -3, -9 and -13 of graft vessels using immunohistochemistry. To clarify the role of MMP-2 in CAV, anti MMP-2 ribozyme was delivered into donor hearts just before transplantation, mediated by a hemagglutinating virus of Japan-liposome complex to specifically suppress MMP-2 activity. RESULTS: All MMPs were immunopositive in SMCs from the slightly thickened neointima at day 15. In the advanced stage of intimal thickening at day 30, in addition to increased number of SMCs, accumulation of collagenous fibers was observed; expression of MMP-3, -9 and -13 was decreased. In contrast, MMP-2 expression remained distinctly positive throughout the progression of the vascular remodeling. After the gene transfer of MMP-2 ribozyme, luminal occlusion was significantly decreased compared to non-treated allografts [25.0+/-6.5 vs. 55.1+/-7.0% (P<0.05)] at day 30 post transplantation. CONCLUSION: MMP-2 is a principle MMP throughout the progression of the vascular remodeling in CAV. Anti MMP-2 therapy could therefore be one of the candidates for a supplemental therapy for CAV.