Study indicates early infusion of mononuclear cells could aid in recovery from stroke

Results of a clinical trial published today in STEM CELLS are the first to document the safety and feasibility of the early administration of bone marrow cells to treat acute ischemic stroke patients.

Results of a clinical trial published today in STEM CELLS are the first to document the safety and feasibility of the early administration of bone marrow cells to treat acute ischemic stroke patients. The information provided by the study could aid in developing new cellular therapies for this most common form of stroke — caused by a blocked artery — which affects over 13 million people each year, according to the World Health Organization.

The study in STEM CELLS is a follow up to the initial report on the first 10 patients in the trial, published in the Annals of Neurology in 2011. The STEM CELLS paper represents the total group of 25 patients.

Sean Savitz, M.D., director of the Institute for Stroke and Cerebrovascular Disease and professor of neurology at McGovern Medical School at UTHealth Houston, was lead investigator on the study. “Having found no clear evidence of harm to the initial 10 patients,” he said, “we broadened the inclusion criteria and enrolled additional patients. Our choice of cell type — bone marrow mononuclear cells (BM MNCs) – dose (10 million cells/kg), timing; route of administration; and the autologous approach was based on, and is in line with, growing evidence from animal stroke models and clinical evidence for possible treatment effects in our traumatic brain injury studies and other diseases.”

BM MNCs are attractive in regenerative medicine studies because they can be rapidly isolated; are enriched with hematopoietic, mesenchymal and endothelial progenitor cells; and permit autologous applications. Preclinical studies consistently indicate that MNCs improve outcome when administered within 72 hours of stroke onset and at least one clinical trial has shown they are not effective beyond seven days, the researchers said.

The regenerative potential of BM-derived MNCs is attributed to various mechanisms that impact stroke recovery. The cells migrate to the site of injury, release cytokines and other trophic factors, decrease proinflammatory and upregulate anti-inflammatory pathways, among other things. They also are easily amenable to autologous infusion, eliminating the need for immunosuppressive drugs.

“In contrast to the generation of autologous mesenchymal stem cells, another promising cell therapy,” added Dr. Savitz, “MNCs do not require passage in culture, which allows for testing in the early post-stroke time window.”

Each patient in the Savitz team’s study received an intravenous dose of their own BM MNCs within 72 hours after onset of their stroke. They were then followed for one year after treatment and the results compared to a control group of 185 acute ischemic stroke patients who received conventional treatment only. No definite severe adverse events related to the procedures were seen in any of the 25 patients, the research showed.


“In the light of our findings,” said Dr. Savitz, “we believe that MNCs pose no additional harm in ischemic stroke patients when given during the acute phase, doses up to 10 million cells/kg are tolerated and it is feasible to perform a BM harvest and re-infusion of MNCs for a wide range of stroke patients. Well-designed random clinical trials are needed to further assess safety and efficacy of this novel approach to enhance stroke recovery.”

“New options to treat Ischemic stroke are desperately needed,” said Dr. Jan Nolta, Editor-in-Chief of STEM CELLS. “This important clinical trial provides solid safety and feasibility data on which later trials can be built, using the patient’s own bone marrow stem/progenitor cells to potentially enhance recovery after ischemic stroke.”

The full article, “Intravenous Bone Marrow Mononuclear Cells for Acute Ischemic Stroke: Safety, Feasibility, and Effect Size from a Phase I Clinical Trial,” can be accessed at

About the Journal: STEM CELLS, a peer reviewed journal published monthly, provides a forum for prompt publication of original investigative papers and concise reviews. The journal covers all aspects of stem cells: embryonic stem cells/induced pluripotent stem cells; tissue-specific stem cells; cancer stem cells; the stem cell niche; stem cell epigenetics, genomics and proteomics; and translational and clinical research. STEM CELLS is co-published by AlphaMed Press and Wiley.

About AlphaMed Press: Established in 1983, AlphaMed Press with offices in Durham, NC, San Francisco, CA, and Belfast, Northern Ireland, publishes three internationally renowned peer-reviewed journals with globally recognized editorial boards dedicated to advancing knowledge and education in their focused disciplines. STEM CELLS® ( is the world’s first journal devoted to this fast paced field of research. THE ONCOLOGIST® ( is devoted to community and hospital-based oncologists and physicians entrusted with cancer patient care. STEM CELLS TRANSLATIONAL MEDICINE® ( is dedicated to significantly advancing the clinical utilization of stem cell molecular and cellular biology. By bridging stem cell research and clinical trials, SCTM will help move applications of these critical investigations closer to accepted best practices.

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Lead investigator on the study, Sean Savitz, M.D.