Knowledge on spinal cord injury in animals and providing a new approach for its treatment using stem cells

In multicellular organisms, stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. They are the earliest type of cell in a cell lineage. They are found in both embryonic and adult organisms, but they have slightly different properties in each. They are usually distinguished from progenitor cells, which cannot divide indefinitely, and precursor or blast cells, which are usually committed to differentiating into one cell type. Stem cells are the body's raw materials — cells from which all other cells with specialized functions are generated. Under the right conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells. Intervertebral disc diseases (IVDD) represent the majority of neurological attendance and responsible for the most cases of paralysis in dogs. Treatments currently used do not show satisfactory results in patients with more severe and chronic neurological manifestations. To promote nerve and muscular recovery, as well as improve quality of life, we aimed to create a double-blind test method, associating spinal decompression surgery and allogeneic transplantation of amniotic membrane-derived stem cells (AMSCs) in dogs with chronic IVDD. Cells were characterized as fetal mesenchymal cells and safe for application. Eight animals completed the experiment: stem cell applications were made in four animals that had previously undergone an unsuccessful surgical procedure (“SC group”, n = ۴); two animals were submitted to surgery, followed by applications of stem cells (“Surgery + SC”, n = ۲); two other animals were submitted to surgery, followed by the application of saline solution (“Surgery + placebo”, n = ۲). During the surgical procedure, a topical application was performed on the lesion and after fifteen and forty-five days another two applications were made via epidural. Animals were monitored biweekly and reassessed three months after surgery, by functional tests and magnetic resonance exams. Some animals presented significant neurological improvement, such as the recovery of nociception and ability to remain on station. Despite the need further studies, until the present moment, cell therapy has been feasible and has no harmful effects on animals. The protocol of preclinical trial showed the association with decompressive surgery and cell transplantation in dogs with thoracolumbar IVDD proved feasible, and it was possible to observe neurological improvement after treatment. No tissue improvement through MRI was found. The double-blind test guaranteed reliability of the evaluations and results obtained that, even with a small sample size, generated satisfactory results for the animals and owners.

Keywords:

cell therapy , spinal cord injury , discopathy , amnion , regenerative medicine