Comorbidity of cardiorespiratory and locomotor dysfunction following cervical spinal cord injury in the rat.

Cervical spinal cord injury interrupts supraspinal pathways innervating thoracic sympathetic preganglionic neurons and results in cardiovascular dysfunction. Both respiratory and locomotor functions were also impaired due to damages of motoneuron pools controlling respiratory and forelimb muscles, respectively. However, no study has investigated autonomic and somatic motor functions in the same animal model. The present study aimed to establish a cervical spinal cord injury model to evaluate cardiorespiratory response and locomotor activity in unanesthetized rats. Cardiovascular response and respiratory behavior following laminectomy or cervical spinal contusion were measured using noninvasive blood pressure analyzer and plethysmography systems, respectively. Locomotor activity was evaluated by an open-field test and a locomotor rating scale. The results demonstrated that mean arterial blood pressure and heart rate were significantly reduced in contused rats compared with uninjured rats at the acute injured stage. Tidal volume was also significantly reduced during the acute and subchronic stages. Moreover, locomotor function was severely impaired, evidenced by decreasing moving ability and locomotor rating scores from the acute to chronic injured stages. Retrograde neurotracer results revealed that cervical spinal cord injury caused a reduction in number of phrenic and triceps motoneurons. Immunofluorescence staining revealed a significant attenuation of serotonergic, noradrenergic, glutamatergic, and GABAergic fibers innervating the thoracic sympathetic preganglionic neurons in chronically contused rats. These results revealed the pathological mechanism underlying the comorbidity of cardiorespiratory and locomotor dysfunction following cervical spinal cord injury. We proposed that this animal model can be used to evaluate the therapeutic efficacy of potential strategies to improve different physiological functions.NEW & NOTEWORTHY The present study establishes a preclinical rodent model to comprehensively investigate physiological functions under unanesthetized condition following cervical spinal cord contusion. The results demonstrated that cervical spinal cord contusion is associated with impairments in cardiovascular, respiratory, and locomotor function. Respiratory and forelimb motoneurons and neurochemical innervations of sympathetic preganglionic neurons were damaged following injury. This animal model can be used to evaluate the therapeutic efficacy of potential strategies to improve different physiological functions.

Therapeutic effect of induced pluripotent stem cell -derived extracellular vesicles in an in vitro and in vivo osteoarthritis model.

Background/Objective: Osteoarthritis (OA) is a multifactorial joint disease associated with the deterioration of chondrocytes and inflammation. Treatment of OA is only aimed at reducing pain and improving joint function. Recently, extracellular vesicles (EVs) secreted from stem cells have emerged as a cell regenerative tool in several degenerative diseases, including OA. We hypothesised that induced pluripotent stem cell (iPSC)-derived EVs would be beneficial for regenerating chondrocytes and OA therapy. Therefore, we aimed to investigate iPSC-EVs' effects on chondrocyte behaviour in an interleukin 1 beta (IL-1ß)-induced in vitro OA model and anterior cruciate ligament transection (ACLT)-induced in vivo OA model of rabbit articular cartilage. Methods: The iPSC-EVs were isolated by sequential ultracentrifugation from a 48-h-incubated conditional medium of iPSC. The isolated iPSC-EVs were characterised by transmission electron microscopy, western blot analyses, and dynamic light scatter. The effects of iPSC-EVs on the viability of human primary chondrocytes and cell senescence were analysed. Premature senescence of cells was induced by long-term incubation with low doses of hydrogen peroxide. To investigate the therapeutic effect of iPSC-EVs on OA chondrocytes in vitro, IL-1ß was used to induce chondrocyte damage. Inflammatory macrophages were activated from THP-1 monocytes to observe the impact of iPSC-EV on macrophage polarisation. The phenotypes of the macrophages exposed to iPSC-EVs were evaluated by ELISA and western blot analyses. The primary chondrocytes were co-cultured with different phenotypes of macrophages to observe the expression of collagen II and catabolic enzymes in chondrocytes. iPSC-EVs were injected intraarticularly into the rabbit with an ACLT-induced OA model. The progression of lesions was assessed through macroscopic and histopathological studies. Results: We showed that iPSC-EVs significantly stimulated the proliferation of primary human chondrocytes and suppressed cell senescence by regulating the expression of p21 and collagen II. iPSC-EVs reduced matrix degradation enzymes and IL-6 expression and attenuated IL-1ß-mediated cell death of chondrocytes. Furthermore, iPSC-EVs modulated macrophage polarisation, resulting in the rescue of damaged chondrocytes in an inflammatory microenvironment. In the rabbit ACLT model, the OA-like lesions, including inflammation, subchondral bone protrusion, and articular cartilage destruction, were ameliorated by iPSC-EV. A histopathological study consistently revealed that iPSC-EVs attenuated ACLT-mediated alteration of MMP13 and ADAMTS5 and collagen II expression. Conclusion: iPSC-EVs protected chondrocytes by enhancing cell proliferation, suppressing premature senescence, and maintaining homeostasis of collagen II synthesis and matrix degradation enzymes such as matrix metalloproteinases (MMPs) and ADAMTS5. iPSC-EVs also reduced cell death in IL-1ß-mediated chondrocyte cell damage. In the rabbit ACLT-induced OA model, iPSC-EV injection reduced cartilage destruction, as indicated by the upregulation of collagen II and down-regulation of MMP13 and ADAMTS5. Overall, our results suggest that iPSC-EVs possess therapeutic potential and may be used as an OA treatment option. The translational potential of this article: This study highlights the potential of iPSC-EVs as a therapeutic option for chondrocyte regeneration and OA treatment.

Human Olfactory Ensheathing Cell-derived Extracellular Cesicles: miRNA Profile and Neuroprotective Effect.

BACKGROUND: Extracellular Vesicle (EV)-based therapy has been identified as a leading alternative approach in several disease models. EV derived from the Olfactory Ensheathing Cell (OEC) has been documented for its strong neuro-regenerative capacity. However, no information on its cargo that may contribute to its therapeutic effect has been available. OBJECTIVE: To report the first miRNA profile of human OEC (hOEC) -EV, and investigate the neuroprotective effects. METHODS: hOEC-EV was isolated and sequenced. We established in vitro experiments to assess the therapeutic potential of hOEC-EVs with respect to insulted neural progenitor cells (NPCs), and the angiogenesis effect. Secondary post-injury insults were imitated using t-BHP-mediated oxidative stress. RESULTS: We noted a strong abundance of hOEC-EV-miRNAs, including hsa-miR148a-3p, hasmiR151a- 3p and several members of let-7 family. The common targets of 15 miRNAs among the top 20 miRNAs were thrombospondin 1 and cyclin dependent kinase 6. We demonstrated that hOEC-EVs promote normal NPC proliferation and differentiation to neuron-like morphologies with prolonged axons. hOEC-EVs protect cells from t-BHP mediated apoptosis. We also found that the migration rate of either NPCs or endothelial cells significantly improved with hOEC-EVs. Furthermore, in vitro tube formation assays indicated that angiogenesis, an important process for tissue repair, was significantly enhanced in human umbilical vein endothelial cells exposed to hOEC-EVs. CONCLUSION: Our results revealed that hOEC-EVs exert neuroprotective effects by protecting cells from apoptosis and promoting in vitro biological processes that are important to neural tissue repair, including neural cell proliferation, axonal growth, and cell migration, in addition to enhancing angiogenesis.