Equine bone marrow MSC-derived extracellular vesicles mitigate the inflammatory effects of interleukin-1ß on navicular tissues in vitro.

BACKGROUND: Safe, efficacious therapy for treating degenerate deep digital flexor tendon (DDFT) and navicular bone fibrocartilage (NBF) in navicular horses is critically necessary. While archetypal orthobiologic therapies for navicular disease are used empirically, their safety and efficacy are unknown. Mesenchymal stem cell-derived extracellular vesicles (EV) may overcome several limitations of current orthobiologic therapies. OBJECTIVES: To (1) characterise cytokine and growth factor profiles of equine bone marrow mesenchymal stem cell (BM-MSC)-derived extracellular vesicles (BM-EV) and (2) evaluate the in vitro anti-inflammatory and extracellular matrix (ECM) protective potentials of BM-EV on DDFT and NBF explant co-cultures in an IL-1ß inflammatory environment. STUDY DESIGN: In vitro experimental study. METHODS: Cytokines (IL-1ß, IL-6, IL-10, IL-1ra and TNF-α) and growth factors (TGFß1, VEGF, IGF1 and PDGF) in equine BM-EV isolated via ultracentrifugation and precipitation methods were profiled. Forelimb DDFT and NBF explant co-cultures from seven horses were exposed to media alone, or media containing 2 × 109 ± 0.1 × 109 particles/mL or 10 µg/mL BM-EV (BM-EV), 10 ng/mL interleukin-1ß (IL-1ß), or IL-1ß + BM-EV for 48 h. Co-culture media IL-6, TNF-α, MMP-3, MMP-13 concentrations and explant sulphated glycosaminoglycan (sGAG) content were quantified. RESULTS: IL-6, IGF1 and VEGF concentrations were 102.1 (37.61-256.2) and 182.3 (163.1-226.3), 72.3 (8-175.6) and 2.4 (0.1-2.6), 108.3 (38.3-709.1) and 211.4 (189.1-318.2) pg/mL per 2 × 109 ± 0.1 × 109 particles/mL or 10 µg/mL 10 µg of BM-EV isolated via ultracentrifugation and precipitation methods, respectively. Co-culture media MMP-3 in BM-EV- (p = 0.03) and BM-EV + IL-1ß-treated (p = 0.01) groups were significantly lower than the respective media and IL-1ß groups. DDFT explant sGAG content of BM-EV (p = 0.003) and BM-EV + IL-1ß groups were significantly higher compared with IL-1ß group. MAIN LIMITATIONS: Specimen numbers are limited, in vitro model may not replicate clinical case conditions, lack of non-MSC-derived EV control group. CONCLUSIONS: Equine BM-EV contains IL-6 and growth factors, IGF1 and VEGF. The anti-inflammatory and ECM protective potentials of BM-EV were evident as increased IL-6 and decreased MMP-3 concentrations in the DDFT-NBF explant co-culture media. These results support further evaluation of BM-EV as an acellular and 'off-the-shelf' intra-bursal/intrasynovial therapy for navicular pathologies.

Zonal characterization and differential trilineage potentials of equine intrasynovial deep digital flexor tendon-derived cells.

BACKGROUND: Intrasynovial deep digital flexor tendon (DDFT) injuries occur frequently and are often implicated in cases of navicular disease with poor outcomes and reinjuries. Cell-based approaches to tendon healing are gaining traction in veterinary medicine and ultimately may contribute to improved DDFT healing in horses. However, a better understanding of the innate cellular characteristics of equine DDFT is necessary for developing improved therapeutic strategies. Additionally, fibrocartilaginous, intrasynovial tendons like the DDFT are common sites of injury and share a poor prognosis across species, offering translational applications of this research. The objective of this study is to isolate and characterize tendon-derived cells (TDC) from intrasynovial DDFT harvested from within the equine forelimb podotrochlear bursa. TDC from the fibrocartilaginous and tendinous zones are separately isolated and assessed. Flow cytometry is performed for mesenchymal stem cell (MSC) surface markers (CD 29, CD 44, CD 90). Basal tenogenic, osteogenic and chondrogenic markers are assessed via quantitative real time-PCR, and standard trilineage differentiation is performed with third passage TDC from the fibrocartilaginous (fTDC) and tendinous (tTDC) zones of DDFT. RESULTS: Low-density plating isolated homogenous TDC populations from both zones. During monolayer passage, both TDC subpopulations exhibited clonogenicity, high in vitro proliferation rate, and fibroblast-like morphology. fTDC and tTDC were positive for MSC surface markers CD90 and CD29 and negative for CD44. There were no significant differences in basal tenogenic, osteogenic or chondrogenic marker expression between zones. While fTDC were largely restricted to chondrogenic differentiation, tTDC underwent osteogenic and chondrogenic differentiation. Both TDC subpopulations displayed weak adipogenic differentiation potentials. CONCLUSIONS: TDC at the level of the podotrochlear bursa, that potentially could be targeted for enhancing DDFT injury healing in horses were identified and characterized. Pending further investigation, promoting chondrogenic properties in cells administered exogenously into the intrasynovial space may be beneficial for intrasynovial tendon regeneration.

Assessing Greenhouse Gas Emissions and Health Co-Benefits: A Structured Review of Lifestyle-Related Climate Change Mitigation Strategies.

This is the first structured review to identify and summarize research on lifestyle choices that improve health and have the greatest potential to mitigate climate change. Two literature searches were conducted on: (1) active transport health co-benefits, and (2) dietary health co-benefits. Articles needed to quantify both greenhouse gas emissions and health or nutrition outcomes resulting from active transport or diet changes. A data extraction tool (PRISMA) was created for article selection and evaluation. A rubric was devised to assess the biases, limitations and uncertainties of included articles. For active transport 790 articles were retrieved, nine meeting the inclusion criteria. For diet 2524 articles were retrieved, 23 meeting the inclusion criteria. A total of 31 articles were reviewed and assessed using the rubric, as one article met the inclusion criteria for both active transport and diet co-benefits. Methods used to estimate the effect of diet or active transport modification vary greatly precluding meta-analysis. The scale of impact on health and greenhouse gas emissions (GHGE) outcomes depends predominately on the aggressiveness of the diet or active transport scenario modelled, versus the modelling technique. Effective mitigation policies, infrastructure that supports active transport and low GHGE food delivery, plus community engagement are integral in achieving optimal health and GHGE outcomes. Variation in culture, nutritional and health status, plus geographic density will determine which mitigation scenario(s) best suit individual communities.