Despite innovations in surgical interventions, treatment of cartilage injury in osteoarthritic joints remains a challenge due to concomitant inflammation. Obstructing a single dominant inflammatory cytokine has shown remarkable clinical benefits in rheumatoid arthritis, and similar strategies are being suggested to target inflammatory pathways in osteoarthritis (OA). Here, we describe the utility of gelatin microspheres that are responsive to proteolytic enzymes typically expressed in arthritic flares, resulting in on-demand and spatiotemporally controlled release of antiinflammatory cytokines for cartilage preservation and repair. These microspheres were designed with a net negative charge to sequester cationic anti-inflammatory cytokines, and the magnitude of the negative charge potential increased with an increase in crosslinking density. Collagenase-mediated degradation of the microspheres was dependent on the concentration of the enzyme. Release of antiinflammatory cytokines from the loaded microspheres directly correlated with the degradation of the gelatin matrix. Exposure of the IL-4 and IL-13 loaded microspheres reduced the inflammation of chondrocytes up to 80%. Hence, the delivery of these microspheres in an OA joint can attenuate the stimulation of chondrocytes and the resulting secretion of catabolic factors such as proteinases and nitric oxide. The microsphere format also allows for minimally invasive delivery and is less susceptible to mechanically induced drug release. Consequently, bioresponsive microspheres can be an effective tool for cartilage preservation and arthritis treatment.
Second career preservice teachers’ perceptions about the out-of-field teaching phenomenon might influence career decisions, such as retention and attrition. A target group of 133 second career graduating Master of Teaching students voluntarily participated in this mixed method study which offered findings through analysed open and Likert-scale questions and semi-structured interview data. The pilot offers new information about second career preservice teachers’ perceptions about their possible involvement in out-of-field teaching practices and the phenomenon’s implications for capabilities, skills knowledge, self-efficacy, support needs and professional identity. A critical reflection on quality teaching and teacher training programs, and preparation for the teaching profession form the foundation for further research in this field. The analyses further stimulate a deeper understanding of the future second career teaching workforce and perceptions of support resources.
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