ABSTRACT
Objective: Osteoarthritis (OA) is a chronic joint disease, with limited treatment options, characterized by inflammation and matrix degradation, and resulting in severe pain or disability. Progressive inflammatory interaction among key cell types, including chondrocytes and macrophages, leads to a cascade of intra- and inter-cellular events which culminate in OA induction. In order to investigate these interactions, we developed a multi-cellular in vitro OA model, to characterize OA progression, and identify and evaluate potential OA therapeutics in response to mediators representing graded levels of inflammatory severity. Methods: We compared macrophages, chondrocytes and their co-culture responses to "low" Interleukin-1 (IL-1) or "high" IL-1/tumor necrosis factor (IL-1/TNF) levels of inflammation. We also investigated response changes following the administration of dexamethasone (DEX) or mesenchymal stromal cell (MSC) treatment via a combination of gene expression and secretory changes, reflecting not only inflammation, but also chondrocyte function. Results: Inflamed chondrocytes presented an osteoarthritic-like phenotype characterized by high gene expression of pro-inflammatory cytokines and chemokines, up-regulation of ECM degrading proteases, and down-regulation of chondrogenic genes. Our results indicate that while MSC treatment attenuates macrophage inflammation directly, it does not reduce chondrocyte inflammatory responses, unless macrophages are present as well. DEX however, can directly attenuate chondrocyte inflammation. Conclusions: Our results highlight the importance of considering multi-cellular interactions when studying complex systems such as the articular joint. In addition, our approach, using a panel of both inflammatory and chondrocyte functional genes, provides a more comprehensive approach to investigate disease biomarkers, and responses to treatment.
ABSTRACT
BACKGROUND: Global collaboration has the potential to induce a shift in research focus away from the priorities of those in low- and low-middle-income countries (LICs and LMICs). This study quantified international collaboration among surgery publications by Fellows of the West African College of Surgeons (WACS) and investigated if collaboration with upper-middle-income and high-income countries (UMICs and HICs) decreases the homophily of research focus. METHODS: Publications by WACS surgery Fellows from 1960 to 2019 were characterized as local WACS publications, collaborative publications without UMIC/HIC participation, or collaborative publications with UMIC/HIC participation. Research topics were determined for each publication, and topic percentages were compared between collaboration groups. RESULTS: We analyzed 5065 publications. Most (3690 publications, 73%) were local WACS publications, while 742 (15%) were collaborative publications with UMIC/HIC participation and 633 (12%) were collaborative publications without UMIC/HIC participation. UMIC/HIC collaborations contributed to 49% of the increase (378 out of 766 publications) from 2000 to 2019. Topic homophily was significantly lower between local WACS publications and collaborations with UMIC/HIC participation (differed in nine research topics) than it was between local WACS publications and collaborations without UMIC/HIC participation (differed in two research topics). CONCLUSIONS: Publications without international collaboration comprise most WACS research, but the rate of UMIC/HIC collaborations is rapidly increasing. We found that UMIC/HIC collaborations decreased the homophily of topic focus in WACS publications, indicating that global collaborations need to have greater emphasis on the priorities of those in LICs and LMICs.
