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Updated: Mar 15, 2026
Intra-Arterial Delivery of Neural Stem Cells to the Rat and Mouse Brain: Application to Cerebral Ischemia
Published on: June 26, 2020
Clinical trial design for stem cell therapies in stroke: What have we learned?
1Institute of Neuroscience and Psychology, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, G51 4TF, UK.
Abstract:
Stem cells of various sources have been investigated in a series of small, safety and feasibility-focused studies over the past 15 years. Understanding of mechanisms of action has evolved and the trial paradigms have become focused on two different approaches - one being an early subacute delivery of cells to reduce acute tissue injury and modify the tissue environment in a direction favourable to reparative processes (for example by being anti-inflammatory, anti-apoptotic, and encouraging endogenous stem cell mobilisation); the other exploring later delivery of cells during the recovery phase after stroke to modulate the local environment in favour of angiogenesis and neurogenesis. The former approach has generally investigated intravenous or intra-arterial delivery of cells with an expected paracrine mode of action and no expected engraftment within the brain. The latter has explored direct intracerebral implantation adjacent to the infarct. Several relevant trials have been conducted, including two controlled trials of intravenously delivered bone marrow-derived cells in the early subacute stage, and two small single-arm phase 1 trials of intracerebrally implanted cells. The findings of these studies and their implications for future trial design are considered.
Insights
Investigating stem cell therapy for stroke shows promise. Early delivery aims to reduce injury, while later delivery promotes healing, guiding future clinical trial designs.
Area of Science:
- Regenerative Medicine
- Neuroscience
- Cell Therapy
Background:
- Over 15 years, stem cell research for stroke has progressed from safety studies to mechanistic understanding.
- Two main therapeutic strategies have emerged: early intervention for acute injury and later intervention for recovery.
Purpose of the Study:
- To review current stem cell trial paradigms for stroke.
- To discuss the implications of existing findings for future clinical trial design.
Main Methods:
- Review of safety and feasibility studies over the past 15 years.
- Analysis of two distinct stem cell delivery approaches: early subacute and late recovery phases.
- Consideration of intravenous, intra-arterial, and intracerebral delivery methods.
Main Results:
- Early cell delivery (intravenous/intra-arterial) focuses on paracrine effects like anti-inflammation and anti-apoptosis.
- Late cell delivery (intracerebral) aims to enhance angiogenesis and neurogenesis post-stroke.
- Existing trials include controlled studies of bone marrow-derived cells and phase 1 trials of intracerebral implantation.
Conclusions:
- Stem cell therapy for stroke is evolving with distinct strategies targeting different phases of recovery.
- Future trials should consider these approaches, delivery methods, and mechanistic insights for optimized patient outcomes.
