Diffuse white matter response in trauma-injured brain to bone marrow stromal cell treatment detected by diffusional kurtosis imaging
Li L, Chopp M, Ding G, Davoodi-Bojd E, Li Q, Mahmood A, Xiong Y, and Jiang Q. Diffuse White Matter Response in Trauma-Injured Brain to Bone Marrow Stromal Cell Treatment Detected by Diffusional Kurtosis Imaging. Brain Res 2019; 1717:127-135.
Diffuse white matter (WM) response to traumatic brain injury (TBI) and transplantation of human bone marrow stromal cells (hMSCs) after the injury were non-invasively and dynamically investigated. Male Wistar rats (300-350g) subjected to TBI were intravenously injected with 1ml of saline (n=10) or with hMSCs in suspension ( approximately 3x10(6)hMSCs, n=10) 1-week post-TBI. MRI measurements of T2-weighted imaging and diffusional kurtosis imaging (DKI) were acquired on all animals at multiple time points up to 3-months post-injury. Functional outcome was assessed using the Morris water maze test. DKI-derived metrics of fractional anisotropy (FA), axonal water fraction (AWF) and radial kurtosis (RK) longitudinally reveal an evolving pattern of structural alteration post-TBI occurring in the brain region remote from primary impact site. The progressive structural change is characterized by gradual disruption of WM integrity at an early stage (weeks post-TBI), followed by spontaneous recovery at a later stage (months post-TBI). Transplantation of hMSCs post-TBI promotes this structural plasticity as indicated by significantly increased FA and AWF in conjunction with substantially elevated RK at the later stage. Our long-term imaging data demonstrate that hMSC therapy leads to modified temporal profiles of these metrics, inducing an earlier presence of enhanced structural remodeling, which may contribute to improved functional recovery.