Animal disease preparedness plans including depopulation guidelines are paramount to prevent the spread of emerging infectious diseases but difficult to implement for swine under field conditions. However, water‐based foam (WBF) is currently an approved and successfully deployed depopulation methodology in poultry. Therefore, the reliability of WBF as a depopulation method and the effectiveness and irreversibility of consciousness and consequential mortality in pigs of different ages was assessed across two trials. Trial 1 investigated the time to loss of consciousness and cessation of cardiac activity in nursery pigs (n = 72) at six different foam immersion time points (2.5, 5, 7.5, 10, 12.5 and 15 min) when placed in a 1.47 m3 (1.2 × 1.2 × 1.02 m, length × width × height) plastic bulk container. One pig per replicate was implanted with an ECG bio‐logger. Irreversible loss of consciousness was observed after a 5‐min immersion. The average (SD) time to development of a fatal arrhythmia from the initiation of the foam application was 7.3 min (1.82 s). Trial 2 aimed to validate the findings from Trial 1 in 75 larger cull sows across three replicates (n = 25). Sows were loaded into a 41‐m3 sealed trailer (12.2 × 1.5 × 2.24 m), immersed in WBF and left undisturbed for 5 min post foam‐filling completion. Six pigs in each replicate were implanted with an ECG bio‐logger. A 5‐min dwell time resulted in irreversible loss of consciousness and subsequent mortality in all cull sows. The average time (SD) to cessation of movement and fatal arrhythmia post foam‐filling completion was 2.2 min (34.8 s) and 8.7 min (138.0 s), respectively. While a 5‐min immersion in WBF induced irreversible loss of consciousness and death in both trials, a 7.5‐min dwell time followed by observation for confirmation of death post WBF removal would be advisable for pigs of all sizes.

Floor cleaning and disinfection are essential components of maintaining animal health status and meeting regulatory requirements in research vivaria. However, best practices for method, frequency, and evaluation techniques have not been established. Reuse of cotton string mop and bucket systems has been implicated in spreading contamination in the human hospital setting. We evaluated 4 different combinations of disinfectant and mop systems commonly used in rodent vivaria. Eight housing rooms were mopped a total of 4 times using one of the following methods: quaternary ammonium compound (QUAT) and cotton string mop (QC), QUAT and microfiber mop (QM), hydrogen peroxide disinfectant (HPD) and cotton string mop (HC), or HPD and microfiber mop (HM). ATP and RODAC samples of the floor were taken before and after mopping. The time to mop each room, floor drying time, and the amount of disinfectant used were recorded. The QC method was associated with significantly more bacterial contamination while all other methods significantly reduced bacterial contamination. The QC method performed significantly worse in reducing bacterial contamination as compared with all other methods when cotton mop heads were reused. All methods except QC significantly reduced ATP levels, with the HC and HM methods being significantly more effective at reducing ATP levels than the QC and QM methods. Costs were similar for the QC, QM, and HM methods. The results of this study indicate that reuse of cotton string mop heads with QUAT increases floor contamination while HPD is effective for up to 3 reuses. Single use microfiber mops were effective with both QUAT and HPD but did not result in more effective cleaning or disinfection than cotton string mops.

Current options for depopulation of adult cattle outlined in the “AVMA Guidelines for the Depopulation of Animals” are limited, have logistic constraints, and may not be practical on a large scale. Water-based foam is advantageous because the necessary equipment is readily available, easy to use and presents minimal personnel risk. Foam has been successfully used to depopulate poultry but no research has been conduct­ed on cattle.

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that leads to progressive joint destruction involving multiple joints. There is a large body of evidence that suggests a crucial role for activated synovial fibroblasts (RASF) in mediating both direct tissue injury and perpetuation of the complex disease process in RA [1]. RASF from RA patients are able to attach to articular cartilage and deeply invade and degrade the cartilage matrix [2] and have been shown to migrate to secondary joint locationsin vivoand invade and degrade cartilage similarly to the primary site [3].Human gingival-derived mesenchymal stem cells (GMSC) are promising therapeutic cell treatments for autoimmune diseases due to their immunomodulatory capacity [4]. Others have demonstrated the ability of GMSC, and exosomes derived from GMSCs (GMSCExo) to suppress the deleteriousin vivoeffects of the collagen induced arthritis model in mice [5].ObjectivesOur aim was to test whether the destructive invasive effects of RASF in anin vivochimeric mouse model of RA could be modulated by the presence of GMSC or GMSCExo. In addition, we analyzed the effects of both GMSC and GMSCExo on the ability of RASF to migrate to secondary locations. Mechanistic studies were done to understand how the GMSC were inhibiting the invasiveness of the RASF.MethodsA chimeric human/mouse model of synovitis was created by surgically implanting SCID mice with a small piece of human articular cartilage surrounded by RASF. Each mouse received two implants; the primary implant on the right flank of the mouse contained RASF, the secondary implant contained no RASF. Mice were retro-orbitally injected once with either GMSC or GMSCExo at 5-7 days post-implantation. The implants were removed after 60 days for evaluation. Histology and IHC were used to assess RASF invasion of the cartilage. Flow cytometry was used to understand the homing ability of GMSCin vivo,the incidence of apoptosis of RASF and the exchange of exosomesin vitro.ResultsWe demonstrate that both GMSC and GMSCExo are potent inhibitors of the deleterious effects of RASF. Both treatments were effective in inhibiting the invasive destructive properties of RASF as well as the potential of these cells to migrate to secondary locations and attack the cartilage there. We also present evidence that GMSC home to the site of the implant and induce programmed cell death of the RASF through the direct transfer of exosomes.ConclusionOur results indicate that both GMSC and GMSCExo can block the pathological effects of RASF in this chimeric model of RA. A single dose of either GMSC or GMSCExo can inhibit the deleterious effects of RASF. These treatments can also block the invasive migration of the RASF, suggesting that they can inhibit the spread of RA to other joints. Because the gingival tissue is harvested with little difficulty, relatively small amounts of tissue are required to expand the cells, the fairly simplein vitroexpansion process, and the increasing technological advances in the production of therapeutic exosomes, we believe that GMSCExo are excellent candidates as a potential therapeutic for RA.References[1] Pap, T., et al., Fibroblast biology. Role of synovial fibroblasts in the pathogenesis of rheumatoid arthritis.Arthritis Res,2000. 2(5): p. 361-7.[2] Muller-Ladner, U., et al., Synovial fibroblasts of patients with rheumatoid arthritis attach to and invade normal human cartilage when engrafted into SCID mice.Am J Pathol,1996. 149(5): p. 1607-15.[3] Lefevre, S., et al., Synovial fibroblasts spread rheumatoid arthritis to unaffected joints.Nat Med,2009. 15(12): p. 1414-20.[4] Gan, L., et al., Dental Tissue-Derived Human Mesenchymal Stem Cells and Their Potential in Therapeutic Application.Stem Cells Int,2020. 2020: p. 8864572.[5] Tian, X., et al.,Gingival mesenchymal stem cell-derived exosomes are immunosuppressive in preventing collagen-induced arthritis. JCell Mol Med, 2022. 26(3): p. 693-708.Acknowledgements:NIL.Disclosure of InterestsNone Declared.

Background Rheumatoid arthritis is a chronic systemic autoimmune disease that involves transformation of the lining of synovial joints into an invasive and destructive tissue. Synovial fibroblasts become transformed, invading and destroying bone and cartilage of the affected joint(s). Due to the significant role these cells play in the progression of the disease process, developing a therapeutic strategy to target and inhibit their invasive destructive nature could help patients who are afflicted with this debilitating disease. Gingival-derived mesenchymal stem cells are known to possess immunomodulatory properties and have been studied extensively as potential cell-based therapeutics for several autoimmune disorders. Methods A chimeric human/mouse model of synovitis was created by surgically implanting SCID mice with a piece of human articular cartilage surrounded by RASF. Mice were injected once with either GMSC or GMSCExo at 5–7 days post-implantation. Histology and IHC were used to assess RASF invasion of the cartilage. Flow cytometry was used to understand the homing ability of GMSC in vivo and the incidence of apoptosis of RASF in vitro.​ Results We demonstrate that both GMSC and GMSCExo are potent inhibitors of the deleterious effects of RASF. Both treatments were effective in inhibiting the invasive destructive properties of RASF as well as the potential of these cells to migrate to secondary locations and attack the cartilage. GMSC home to the site of the implant and induce programmed cell death of the RASF.​ Conclusions Our results indicate that both GMSC and GMSCExo can block the pathological effects of RASF in this chimeric model of RA. A single dose of either GMSC or GMSCExo can inhibit the deleterious effects of RASF. These treatments can also block the invasive migration of the RASF, suggesting that they can inhibit the spread of RA to other joints. Because the gingival tissue is harvested with little difficulty, relatively small amounts of tissue are required to expand the cells, the simple in vitro expansion process, and the increasing technological advances in the production of therapeutic exosomes, we believe that GMSCExo are excellent candidates as a potential therapeutic for RA.