Enhancing therapeutic potential of olfactory ensheathing cells in spinal cord injury by phagocytosis

Under normal physiological condition the body needs to fight bacterial infection, clear old dead or dying cells as well as regenerate new ones. Phagocytosis is the immunological process required for cells to digest and destroy particulates thereby maintaining a systemic homeostasis. Phagocytosis involves four steps of recognition, engulfment, formation of phagosome, degradation and elimination. In the nervous system, the phagocytes are the glial cells which support the system framework, primarily microglia. Spinal cord injury is an irreparable nervous system injury and restoration of function is very difficult. One strategy which could aid repair and regeneration is to enhance the phagocytic process thereby removing cell debris and bacteria from the injury site. Glial cells are involved in phagocytosis and clearing the spinal cord injury area. Understanding this process may improve strategies to develop therapy, particularly those that involve cell transplantation such as peripheral nerve glia. Within the nervous system, the main phagocytic glia, which has been studied, in the central nervous system (CNS) are astrocytes and microglia, and in the peripheral nervous system (PNS), the main glia are Schwann cells for most nerves, with olfactory ensheathing cells (OECs) in the olfactory nerve. In this study, my first objective was to compare the CNS and PNS cells like astrocytes, microglia, OECs and trigeminal Schwann cells (TgSCs) for their antimicrobial response to bacterial infection (S. aureus). Results showed live bacteria could be isolated from all glia after 24 h in culture, and microglia, OECs and TgSCs exhibited better protection against intracellular S. aureus survival than astrocytes. All glial types responded to the bacteria by cytokine secretion, but overall, OECs secreted the lowest level of cytokines. Debris clearance is crucial for neural regeneration and OECs have the ability to phagocytose both bacteria and cell debris. OECs and SCs are being considered
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Pharmacy & Med Sci
Griffith Health
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