Stem Cell Transplantation for Ischemic Stroke
Studies in animal models of ischemic stroke have shown that stem cells transplanted into the brain can lead to functional improvement. However, to date, evidence for the benefits of stem cell transplantation in patients with ischemic stroke is lacking. Our objective was to assess the efficacy and safety of stem cell transplantation compared with conventional treatments in patients with ischemic stroke.
We searched the Cochrane Stroke Group Trials Register (last searched February 2010), the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2009, Issue 3), MEDLINE (1966 to August 2008), EMBASE (1980 to August 2008), Science Citation Index (1900 to August 2008), and BIOSIS (1926 to August 2008). We hand-searched potentially relevant conference proceedings, screened reference lists, and searched ongoing trials and research registers. We also contacted individuals active in the field and stem cell manufacturers.
We included randomized controlled trials recruiting patients with ischemic stroke, in any phase of the disease, and an ischemic lesion confirmed by CT or MRI scan. We included all types of stem cell transplantation regardless of cell source (autograft, allograft, or xenograft; embryonic, fetal, or adult; from brain or other tissues), route of cell administration (systemic or local), and dosage. The primary outcome was efficacy (assessed as combined functional outcome or disability and dependency) at longer follow-up (minimum 6 months). Secondary outcomes included postprocedure safety outcomes (death, worsening of neurological deficit, infections, and neoplastic transformation).
We identified 3 very small randomized controlled trials. Of these, 2 are still awaiting classification because only subgroups of patients could be included in this meta-analysis and additional unpublished data are needed. The third trial randomized 30 patients to intravenous transplantation of autologous mesenchymal stem cell (10 participants) or a reference group (20 participants; 5 participants, initially randomized to the intervention group, refused the treatment, and were allocated to the reference group) and found a statistically nonsignificant functional improvement in treated patients at longer follow-up. No adverse cell-related events were reported.
Implications for Practice
No large trials of stem cell transplantation have been performed in patients with ischemic stroke and it is too early to know whether this intervention can improve functional outcome.
Implications for Research
Large and well-designed trials are needed.
This article is based on a Cochrane Review published in The Cochrane Library 2010, Issue 9 (see www.thecochranelibrary.com for information). Cochrane Reviews are regularly updated as new evidence emerges and in response to feedback, and The Cochrane Library should be consulted for the most recent version of the review.1
- Received September 28, 2010.
- Revision received October 26, 2010.
- Accepted October 27, 2010.
- © 2011 American Heart Association, Inc.