Skip to main content
2024 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Tissue Engineering

Tissue Engineering - Poster Session D

Poster L5 - Stimulating endogenous neurogenesis improves tissue regeneration after extracellular matrix hydrogel implantation in stroke.

Friday, October 25, 2024
3:30 PM - 4:30 PM EST
Location: Exhibit Hall E, F & G

Introduction:  An endogenous neurogenic response in the brain is caused by a stroke and participates in the repair of damaged tissues. However, neurogenesis is not able to replace lost tissue. The extracellular matrix (ECM) has been shown to act as a functional bioscaffold to fill tissue cavities caused by a stroke, while promoting the infiltration of neural progenitors that contribute to a de novo tissue formation [1]. Still, this invasion of neural progenitors is insufficient to achieve a neuronal density matching homologous tissue. We here hypothesized that a stimulation of neurogenesis with a neural growth factor, betacellulin (BTC), will increase the neuronal density in de novo tissue.

Materials and

Methods:  A transient right Middle Cerebral Artery occlusion (MCAo) was performed as a rat model of stroke. ECM was injected and semi-osmotic pumps (Alzet) were placed 14 days post-stroke and BTC was delivered continuously into the lateral ventricle for 14 days. Rats were perfused transcardially 28 days post-stroke. Sox2, a gene mainly expressed in neural stem cells in neurogenic niches—including the subventricular zone (SVZ), subcallosal zone (SCZ), and the subgranular zone of the dentate gyrus—served as a marker for neurogenesis. 50μm thick sections were stained with anti-Sox2 primary antibody, with corresponding AlexaFluor secondary antibodies and Hoechst as a nuclear counterstain. Images were acquired using a Keyence BZ-X810 microscope and processed in FIJI to remove background and quantify Sox2+ cell density in the SVZ, SCZ, the striatum, cortex, and the bioscaffold. Averages were calculated per section and per slide (4 sections) and graphed in Prism 10 (GraphPad). One-way ANOVA (with Bonferroni post-hoc testing) or Student’s t-test tests were run with a significance of p< 0.05.

Results, Conclusions, and Discussions: The density of Sox2+ cells was significantly increased in MCAo + ECM + BTC across the SVZ, striatal tissue and bioscaffold compared to naïve animals. Although Sox2 density was higher in naïve + BTC and MCAo only animals compared to naive, it did not reach statistical significance. However, MCAo animals with BTC or ECM injections exhibited significantly increased neurogenesis. The bioscaffold region was segmented into striatal and cortical regions in each animal based on the nature of the damaged tissue. In the striatal bioscaffold, BTC revealed a marked increase in Sox2+ cell density. This suggests that the infusion of BTC in the ventricle following a stroke increases the density of neural stem cells throughout the brain. The combination of BTC and ECM injection to the lesion produced the largest increase in Sox2+ cell density, further supporting that ECM is a viable bioscaffold material to encourage the invasion of new cells to the stroke lesion. Further immunohistochemical analysis using DCX (doublecortin), a marker for young migrating neurons, and NeuN, a marker for mature neurons, is needed to understand the full effect BTC has on the cellular composition of the bioscaffold. Stimulation of endogenous neurogenesis with BTC was effective and produced a significant increase in neural progenitors invading the bioscaffold. This approach could hence provide a more efficient process to promote tissue regeneration after a stroke.

Acknowledgements (Optional):  [1] Damian, Corina et al. (2021). Post-Stroke Timing of ECM Hydrogel Implantation Affects Biodegradation and Tissue Restoration. International journal of molecular sciences, 22(21), 11372.

This research was funded by the National Institute for Neurological Disease and Stroke (R21NS118399). Kylie Wishneski was supported by the Department of Radiology, the Swanson School of Engineering, and the Frederick Honors College at the University of Pittsburgh.