Delayed Transplantation of Neural Stem Cells Improves Initial Graft Survival after Stroke

Area of Science:

• Neuroscience
• Regenerative Medicine
• Stem Cell Biology

Background:

• Stroke creates a hostile microenvironment hindering neural stem cell therapy efficacy.
• The evolving nature of the stroke microenvironment necessitates identifying optimal transplantation timing.
• Uncertainty exists regarding whether acute or delayed cell transplantation benefits graft survival post-stroke.

Purpose of the Study:

• To determine the optimal transplantation window for neural progenitor cells (NPCs) after stroke.
• To compare the efficacy of acute versus delayed intracerebral transplantation of human induced pluripotent stem cell-derived NPCs.
• To investigate the impact of transplantation timing on graft survival, proliferation, and differentiation in a stroke model.

Main Methods:

• Utilized a mouse model of large cortical stroke.
• Transplanted human induced pluripotent stem cell-derived neural progenitor cells (iPSCs-NPCs) at acute (1 day) and delayed (7 days) post-stroke time points.
• Employed in vivo bioluminescence imaging over 6 weeks to monitor graft survival and proliferation.

Main Results:

• Delayed NPC transplantation (7 days post-stroke) significantly enhanced graft proliferation and survival compared to acute transplantation (1 day post-stroke).
• In vivo imaging revealed a >5-fold increase in bioluminescence signal in delayed transplantation group over 6 weeks.
• Increased early proliferation drove enhanced cell numbers in delayed group; differentiation into neurons was observed in both groups after 6 weeks.

Conclusions:

• Delayed intracerebral transplantation of iPSCs-NPCs at 7 days post-stroke optimizes early graft survival and proliferation.
• These findings suggest a critical therapeutic window for maximizing the effectiveness of NPC-based stroke recovery therapies.
• Optimizing transplantation timing is crucial for enhancing the success of neural stem cell therapies in stroke patients.