Intranasal delivery of neural stem cells alone or in combination with environmental enrichment as a potential therapy for experimental TBI

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Traumatic brain injury (TBI) affects more than 10 million individuals worldwide each year and is a major cause of disability, resulting in long-term functional deficits for TBI survivors. To date, the major unmet needs for treating TBI are effective strategies to restore neuronal networks and recover function. Although pharmacologic strategies are the most common approach to treat TBI, they, and other approaches, are hindered by blood-brain- barrier (BBB) permeability. Therefore, a therapeutic approach that circumvents the BBB is needed. Neural stem cell (NSC)-based therapies may be a feasible alternative to pharmacotherapies for improving function after TBI. However, stem cell-based therapies are contingent on efficient delivery to the areas of damage. In our pilot TBI studies, well-characterized allogeneic human NSCs genetically modified to express the human L-Myc gene (LM- NSC008) migrated to and distributed at damaged brain regions, and rats showed improved spatial learning after receiving intranasally delivered NSCs. We hypothesize that 1) intranasally-delivered LM-NSC008 NSCs will migrate to TBI sites, accumulate in sufficient quantities, and contribute to motor and cognitive recovery post-injury, and 2) augmenting NSCs with environmental enrichment (EE) will provide further benefits. To test our hypothesis and optimize NSC delivery, we propose three Aims. Aim 1: To determine the optimal dose of NSC delivery for maximal distribution to areas of TBI damage. We will test two dosing paradigms: one of two bolus doses (6x106 or 12x106 NSCs) or vehicle will be given on day 7 after moderate TBI or sham injury, or a lower dose (1x106 or 2x106 NSCs) will be given on alternate days starting on day 7 post-surgery through day 17. Computational analytical methods applied to optically-cleared brain sections (CLARITY technique) will be used to quantify and validate NSC migration and distribution in TBI vs. shams. Characterizing NSC distribution in 3D tissue combined with route finding algorithms will allow us to predict NSC dosing-dependent routes of migration and brain tissue biodistribution. Aim 2: To determine the extent to which NSC therapy improves motor outcome and cognition (reference memory and executive function). The optimal dose of NSCs, determined by the greatest distribution at the site of injury, from Aim 1 will be administered to separate cohorts of rats at one of three times (7-d [acute phase], 21-d [delayed phase], and 3-mo [chronic phase]) after TBI or sham injury. Aim 3: To determine the effect of combining EE with NSC therapy on motor and cognitive benefits. The NSC regimen used in Aim 2 will be combined with a clinically-relevant rehabilitation paradigm of 4 h of EE per day, which we have optimized to mimic patient time in the clinic. The EE receiving groups will be compared to standard-housed (non-enriched) groups in Aim 2. We expect that the combination will be more effective at improving motor and cognitive function than NSC therapy alone. All experiments will include male and normal cycling female rats. Achieving the specific aims has the potential to make tremendously improve the treatment of TBI patients and potentially impact therapeutic paradigms for other neurodegenerative diseases.