Evaluation of intrathecal transplantation of allogeneic mesenchymal stem cells into healthy and neurological sequelae horses

Mesenchymal stem cells (MSC) have anti-inflammatory, immunomodulatory, neuroprotective and neuro-regenerative properties. Due to the limited regenerative capacity of neural tissue, the therapeutic potential of stem cells has been studied in several pathological conditions of the central nervous system (CNS). Therefore, the objective of this study was to evaluate the viability, safety and the response to successive intrathecal injections of MSC from different sources in horses. For that, the transdifferentiation, therapeutic potential and co-culture of MSC with cerebrospinal fluid (CSF) from bone marrow, adipose tissue and umbilical cord were evaluated. Later, MSC were used for intrathecal (IT) transplantation through the lumbosacral cistern (LS), atlanto-occipital (AO) and between the C1-C2 vertebrae into healthy horses (HG), totalizing 3 injections between 30 days apart. Additionally, MSC tracking were performed after AO and LS transplantation. After this step, MSC were used for IT transplantation through the space between the C1-C2 vertebrae in horses with Equine Protozoal Myeloencephalitis (EPM) sequelae - sick group (SG) under the same protocol. All animals (HG and SH) were evaluated by serial clinical and neurological exams, hematological and CSF analysis before and after transplantation. The results demonstrated that MSC from several sources is a possibility of therapy for the CNS diseases, because their behavior in the presence of CSF have shown positive effects, it is a safe and viable therapy using different intrathecal routes, and safe even with high doses and successive transplants of MSC. In addition, IT transplantation between C1-C2 has been shown to be more feasible to be performed in the field and in animals with neurological signs. Finally, MSC therapy demonstrated beneficial effects for chronic sequelae in the spinal cord from EPM. (AU)