2017 ACVIM Forum Research Abstract Program

Both CD4 + CD25 + FoxP3 + Tregs and CD4 + FoxP3 + Tregs may have a relevance to the pathogenesis of CAD in course of atopic dermatitis. This study demonstrated negative association between Treg frequency and disease severity. The numbers of circulating tregs of atopic dogs decreased as they got older. Francisella tularensis, a pathogenic Gram negative intracellular bacteria that causes pneumonia, skin lesions, and systemic illness known as Tularemia that can affect cats in certain regions of the United States. 12/15 lipoxygenase (LO) is an enzyme that utilizes arachidonic acid to produce anti-inflammatory mediators. Deletion would be expected to produce an increase in the severity of disease. Since 12/15-LO has a role in regulating inflammation, our hypothesis is pneumonic tularemia in mice would produce increases in morbidity and mortality. Francisella tularensis Live Vaccine Strain (Ft LVS) is pathogenic to mice but not to people. C3H wild type (WT) and 12/15 LO knock out (KO) mice were infected intratracheally with a sublethal dose of Ft LVS and their weights were monitored for 10 days. On day 10 post-infection the mice were euthanized and the lungs, spleens, and liver were collected for analysis. The cellular phenotype of infiltrating inflammatory cells, leukotriene B4 (LTB4) and KC levels were determined from lung tissue. Histopathology was assessed from the lung and liver, and splenic weights were determined. 12/15 LO KO mice had increased morbidity compared to WT mice indicated by their significant weight loss. KC, a chemoattractant for neutrophils, was significantly (P < 0.05) higher in the lung tissue of KO mice. Inflammatory cells (neutrophils, T cells, and macrophages) and pulmonary histopathology scores were significantly higher (P < 0.05) in KO mice. In contrast LTB4, which assists in host defense was significantly decreased (P < 0.05) in 12/15 LO KO mice. Splenic weights were significantly (P < 0.05) higher than WT spleens correlating with the severity of disease. Given this information, 12/15 LO plays a role in regulating inflammation in pneumonic Tularemia. Eicosanoids are highly conserved among species and It is possible that 12/15 LO agonists may be used as natural therapeutics to aide in the resolution of pneumonia in domestic animals, but further studies are needed. Mesenchymal stem cells (MSCs) have immunomodulatory functions and differentiation capacity, conferring them with various clinical uses. Although MSCs have been applied in the treatment in various inflammatory diseases, mechanistic research on feline MSCs is lacking. Accordingly, in this study, we aimed to analyse the immunomodulatory mechanisms of MSCs isolated from feline adipose tissue (fAT-MSCs). Cytokine expression in RAW264.7 murine macrophages and allogeneic feline peripheral blood mononuclear cells (fPBMCs) was measured using quantitative real-time polymerase chain reaction (qRT-PCR) and compared according to the presence of fAT-MSCs. We also extracted RNA and collected supernatants from fAT-MSCs for measurement of soluble factor expression levels by qRT-PCR and enzyme-linked immunosorbent assay. The levels of pro-inflammatory cytokines, e.g., tumour necrosis factor-a (TNF-a), inducible nitric oxide synthase and interleukin (IL)-1b, were significantly decreased in coculture of mitogen-stimulated RAW264.7 cells with fAT-MSCs compared with that in RAW264.7 cells. Additionally, the expression of immunomodulatory factors from fAT-MSCs, including cycloo