Homing of peripherally injected bone marrow cells in rat after experimental myocardial injury

Background and objectives: significant progress has been achieved during the past 10 years in cell transplantation and recent research has focused on the possibility of improving ventricular function after myocardial infarction. Most studies in the field of cardiac tissue repair are performed by direct intramyocardial injection of cells of different origin. Since this approach requires a surgical intervention, in this study we investigated the feasibility of non-invasive administration of bone marrow mononuclear cells (BMMNCs) by assessing the fate of peripherally injected, purified, labeled cells in cryodamaged hearts. Design and methods: ten donor and ten recipient inbred isogenic adult (4 weeks old) Fisher rats were used as models to mimic autologous transplantation. Myocardial damage was obtained in recipient rats by placing a frozen metal probe on the anterior left ventricular wall for 15 seconds (freeze-thaw injury technique). BMMNCs were purified and labeled with a red fluorescent cell dye. Seven days after the injury about 15-25x10(6) cells were infused through the femoral vein of recipient rats. Seven days after the infusion, the heart, lungs, liver, kidneys, spleen and thymus were harvested to track transplanted cells. RESULTS: Labeled cells were found only in the injured area of the heart and not in the normal tissue, and a limited number of cells were identified in the spleen of all the animals. Most of the labeled cells in the infarcted area were Thy-1(+) and some were CD34(+). Interpretation and conclusions: our data suggest that peripherally injected BMMNCs can traffic through the circulation to the site of damage; we hypothesize that tissue injury leads to the priming of a cytokine cascade acting as chemoattractant for the infused cells

Intestinal microbiota sustains inflammation and autoimmunity induced by hypomorphic RAG defects

Omenn syndrome (OS) is caused by hypomorphic Rag mutations and characterized by a profound immunodeficiency associated with autoimmune-like manifestations. Both in humans and mice, OS is mediated by oligoclonal activated T and B cells. The role of microbial signals in disease pathogenesis is debated. Here, we show that Rag2R229Q knock-in mice developed an inflammatory bowel disease affecting both the small bowel and colon. Lymphocytes were sufficient for disease induction, as intestinal CD4 T cells with a Th1/Th17 phenotype reproduced the pathological picture when transplanted into immunocompromised hosts. Moreover, oral tolerance was impaired in Rag2R229Q mice, and transfer of wild-type (WT) regulatory T cells ameliorated bowel inflammation. Mucosal immunoglobulin A (IgA) deficiency in the gut resulted in enhanced absorption of microbial products and altered composition of commensal communities. The Rag2R229Q microbiota further contributed to the immunopathology because its transplant into WT recipients promoted Th1/Th17 immune response. Consistently, long-term dosing of broad-spectrum antibiotics (ABXs) in Rag2R229Q mice ameliorated intestinal and systemic autoimmunity by diminishing the frequency of mucosal and circulating gut-tropic CCR9+ Th1 and Th17 T cells. Remarkably, serum hyper-IgE, a hallmark of the disease, was also normalized by ABX treatment. These results indicate that intestinal microbes may play a critical role in the distinctive immune dysregulation of OS

Aero-thermal Characteristics of an Automotive CCM Vented Brake Disc

The paper reports on an experimental investigation of the aero-thermal behavior of a vented automotive brake disc. A CCM disc with radial cooling channels and drilling holes was tested. Local mean temperature and velocity measurements at disc exit were carried out; global parameters, as the vented mass flow rate and the convective heat transfer coefficient were then evaluated. It was found that the flow structure scales with the rotational speed and the braking conditions. The vented mass flow rate decreases with increasing the disc temperature. The heat flux increase with increasing disc temperature is not linear. The convective heat transfer coefficient showed large values, that are well correlated with the Reynolds number by common empirical correlations for heat exchangers

Fusion between cancer cells and macrophages occurs in a murine model of spontaneous neu+ breast cancer without increasing its metastatic potential

Cell fusion between neoplastic and normal cells has been suggested to play a role in the acquisition of a malignant phenotype. Several studies have pointed to the macrophage as the normal partner in this fusion, suggesting that the fused cells could acquire new invasive properties and become able to disseminate to distant organs. However, this conclusion is mainly based on studies with transplantable cell lines. We tested the occurrence of cell fusion in the MMTV-neu model of mouse mammary carcinoma. In the first approach, we generated aggregation chimeras between GFP/ neu and RFP/neu embryos. Tumor cells would display both fluorescent proteins only if cell fusion with normal cells occurred. In addition, if cell fusion conferred a growth/dissemination advantage, cells with both markers should be detectable in lung metastases at increased frequency. We confirmed that fused cells are present at low but consistent levels in primary neoplasms and that the macrophage is the normal partner in the fusion events. Similar results were obtained using a second approach in which bone marrow from mice carrying the Cre transgene was transplanted into MMTV-neu/LoxP-tdTomato transgenic animals, in which the Tomato gene is activated only in the presence of CRE recombinase. However, no fused cells were detected in lung metastases in either model. We conclude that fusion between macrophages and tumor cells does not confer a selective advantage in our spontaneous model of breast cancer, although these data do not rule out a possible role in models in which an inflammation environment is prominent

Monovalency Unleashes the Full Therapeutic Potential of the DN-30 Anti-Met Antibody*

Met, the high affinity receptor for hepatocyte growth factor, is one of the most frequently activated tyrosine kinases in human cancer and a validated target for cancer therapy. We previously developed a mouse monoclonal antibody directed against the extracellular portion of Met (DN-30) that induces Met proteolytic cleavage (receptor “shedding”) followed by proteasome-mediated receptor degradation. This translates into inhibition of hepatocyte growth factor/Met-mediated biological activities. However, DN-30 binding to Met also results in partial activation of the Met kinase due to antibody-mediated receptor homodimerization. To safely harness the therapeutic potential of DN-30, its shedding activity must be disassociated from its agonistic activity. Here we show that the DN-30 Fab fragment maintains high affinity Met binding, elicits efficient receptor shedding and down-regulation, and does not promote kinase activation. In Met-addicted tumor cell lines, DN-30 Fab displays potent cytostatic and cytotoxic activity in a dose-dependent fashion. DN-30 Fab also inhibits anchorage-independent growth of several tumor cell lines. In mouse tumorigenesis assays using Met-addicted carcinoma cells, intratumor administration of DN-30 Fab or systemic delivery of a chemically stabilized form of the same molecule results in reduction of Met phosphorylation and inhibition of tumor growth. These data provide proof of concept that monovalency unleashes the full therapeutic potential of the DN-30 antibody and point at DN-30 Fab as a promising tool for Met-targeted therapy