Mesenchymal stem cells (MSC) have been shown to improve wound healing and sup-press inflammatory immune responses. Newer research also indicates that MSC exhibit antimicrobial activity, although the mechanisms underlying this activity have not been fully elucidated. Therefore, we conducted in vitro and in vivo studies to examine the ability of resting and activated MSC to kill bacteria, including multidrug resistant strains. We investigated direct bacterial killing mechanisms and the interaction of MSC with host innate immune responses to infection. In addition, the activity of MSC against chronic bacterial infections was investigated in a mouse biofilm infection model. We found that MSC exhibited high levels of spontaneous direct bactericidal activity in vitro. Moreover, soluble factors secreted by MSC inhibited Staphylococcus aureus biofilm formation in vitro and disrupted the growth of established biofilms. Secreted factors from MSC also elicited synergistic killing of drug-resistant bacteria when combined with several major classes of antibiotics. Other studies demonstrated interactions of activated MSC with host innate immune responses, including triggering of neutrophil extracellular trap formation and increased phagocytosis of bacteria. Finally, activated MSC administered systemically to mice with established S. aureus biofilm infections significantly reduced bacterial numbers at the wound site and improved wound healing when combined with antibiotic therapy. These results indicate that MSC generate multiple direct and indirect, immunologically mediated antimicrobial activities that combine to help eliminate chronic bacterial infections when the cells are administered therapeutically.
Jamaican fruit bats (Artibeus jamaicensis) are used as an animal model for several viruses, including Middle East respiratory syndrome virus, dengue virus, Zika virus, and Tacaribe virus. However, despite ongoing studies regarding these pathogens, little is known regarding the bats' normal physiology. In this study, phlebotomy of the propetagial (cephalic) vein was performed to establish baseline hematologic parameters in an apparently healthy, captive population of Jamaican fruit bats. Furthermore, we compared results from physically restrained and isoflurane-anesthetized bats. Our findings indicate significant increases in WBC count, lymphocytes, and monocytes in the anesthetized bats. However, RBC and platelet parameters were not different between the 2 groups. This information on the normal hematologic parameters of Jamaican fruit bats, adds to our overall understanding of the normal physiology of this species, and expands our knowledge on bat species in general.
Antimicrobial resistance and biofilm formation both present challenges to treatment of bacterial infections with conventional antibiotic therapy and serve as the impetus for development of improved therapeutic approaches. Mesenchymal stromal cell (MSC) therapy exerts an antimicrobial effect as demonstrated in multiple acute bacterial infection models. This effect can be enhanced by pre-conditioning the MSC with Toll or Nod-like receptor stimulation, termed activated cellular therapy (ACT). The purpose of this review is to summarize the current literature on mechanisms of antimicrobial activity of MSC with emphasis on enhanced effects through receptor agonism, and data supporting use of ACT in treatment of bacterial infections in veterinary species including dogs, cats, and horses with implications for further treatment applications. This review will advance the field’s understanding of the use of activated antimicrobial cellular therapy to treat infection, including mechanisms of action and potential therapeutic applications.
professional growth and development, and a well-organized program to introduce junior faculty to the institution's research culture could greatly improve outcomes 4. Leadership development may also be useful to ensure that department chairs communicate with their faculty, particularly those that are new and inexperienced. The IO can function as a staunch advocate of efforts to improve the overall animal research program and outcomes to the benefit of faculty, staff, and the animals.
A 15-year-old spayed female mixed-breed dog was presented to the Ohio State University Veterinary Medical Center for a gingival mass and progressive anorexia. Prior history included moderate dental disease, chronically increased liver enzymes, a recently diagnosed liver mass, and intermittent urinary tract infections. At the time of presentation, she was receiving doxycycline at a dose of 5 mg/kg PO q12h as empirical treatment for a suspected urinary tract infection based on recent hematuria. On physical examination, a 1.5 cm × 2 cm, raised, pink, firm gingival mass extended along the left maxillary premolar region with a smaller, red, ulcerated mass just rostral to the primary mass. Fine-needle aspirate preparations of the larger, firm gingival mass were submitted for evaluation (Figure 1). Cytologic Interpretation: Carcinoma, concerning for metastatic urothelial cell carcinoma (UC).Cytologic Description: Five direct smears were highly cellular with variably cohesive clusters of oval to polygonal cells in a background of blood. The cells were characterized by a low to moderate nuclear-to-cytoplasmic ratio with marked anisocytosis and anisokaryosis. Moderate amounts of moderately to deeply basophilic granular cytoplasm sometimes displayed wispy to irregular borders. Occasionally, the cells contained round, variably sized eosinophilic inclusions consistent with Melamed-Wolinska bodies.
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