In vitro metabolic assessment of bone marrow-derived stem cells and its application to central nervous system trauma
Abstract
Trauma to the central nervous system (CNS) results in devastating consequences for those afflicted. Both spinal cord injury (SCI) and traumatic brain injury (TBI) can result in varying degrees of sensorimotor function loss, with TBI typically accompanied by cognitive damage. At the cellular level, central nervous system trauma typically consists of neurite connection damage, which in turn can lead to neuronal and glial necrosis, as well as permanent loss of neurological function. A deeper understanding of CNS trauma has been formed through numerous in vitro and in vivo studies. In vitro injury models have been used to isolate specific outcomes of injury, while in vivo injury models have contributed insight into how individual characteristics of injury combine to create long-term secondary effects. Additionally, both model categories have been used to evaluate a myriad of potential treatments, with some so promising that they have eventually been tested in human trials. Two of the most promising treatments for CNS injury have been external electric field application and adult stem cell implantation. Implantable electric field stimulators have been proven to induce axonal regeneration and improve neurological function after SCI in animal studies. Implanted bone marrow-derived adult stem cells have also demonstrated this ability. Additionally, these stem cells have exhibited some promise in treating TBI. During in vivo CNS trauma experiments involving stem cell implantation, the cells' metabolic state is rarely considered either before or after implantation at the injury site. Before implantation, the stem cells are typically differentiated in culture environments with a higher glucose concentration than the area of the CNS at which they will eventually be implanted. This is an important consideration because the discrepancy in energy availability may affect the stem cells' terminal differentiation post-implantation. However, the first step to answering such a question is to investigate whether or not the cells' metabolic state is altered with changes to their environment's glucose concentration. This dissertation details a series of in vitro experiments designed to evaluate metabolism and viability characteristics of bone marrow-derived stem cells while compared to a neural tissue model in the form of PC12 cells. More specifically, it contains a discussion pertaining to a CNS injury simulation study to assess the cells' viability after various changes to the injury profile. Afterward, it details the results of a metabolism study in which the cells were subjected to culture environments with glucose concentrations reflective of either typical pre-implantation, in vitro culture or post-injury CNS tissue. Additionally, it assesses the metabolic state of the cells to better understand how a potential combination with external electric field-based therapy may affect the metabolism of both the stem cells and the injured CNS tissue. Overall, the contributions of this research will aid in the design of stem cell treatments for CNS injury at the critical juncture moving from in vitro culture to in vivo implantation.
Degree
Ph.D.
Advisors
Nauman, Purdue University.
Subject Area
Cellular biology|Neurobiology
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