Long-term effects of xenotransplantation of human enteric glia in immunocompetent rats with brain injury

BackgroundAcute brain injury is characterized by extensive tissue damage, resulting in neuronal loss and functional deficits in patients. The capacity of nerve tissue to self-regenerate is insufficient to repair damaged tissue, thus therapies based on exogenous cells are urgently needed. Human enteric glia (EG) have interesting intrinsic properties that make them a valuable candidate for regenerative medicine. In this long-term study, we investigated whether human EG treatment induces tissue repair and improves functional recovery in a rat model of brain injury. MethodsAcute brain injury was induced by malonate injection in the motor cortex of female rats, causing extensive tissue damage and long-lasting sensorimotor deficits. Human EG were isolated from gut tissue, expanded and administered intranasally in awake immunocompetent rats. To determine the long-term safety and efficacy of human EG treatment, longitudinal evaluation of sensorimotor function, post-mortem tissue regeneration and the fate of human EG were assessed thirty-six weeks after intranasal administration. ResultsTransplanted human EG satisfied the safety criteria, non-immunogenic and non-tumorigenic, required for cell therapy; they were well tolerated in immunocompetent rats, and induced sensorimotor improvement. Importantly, thirty-six weeks post-treatment, intranasally delivered human EG were detected in the rat brain, mainly in the injured motor cortex. This indicated that transplanted human EG migrated and successfully engrafted and integrated with the host tissue. Additionally, human EG induced tissue regeneration by enhancing endogenous angiogenesis and neurogenesis. Notably, thirty-six weeks after administration, human EG generated mature neurons that were enveloped by oligodendrocytes and formed synaptic connections with the host tissue. ConclusionsTransplanted human EG induced tissue repair and showed regenerative potential after brain injury. This is the first study demonstrating the feasibility, safety and efficacy of intranasal administration of human EG for treatment of brain injury.