Stroke is a worldwide cause of disability and death. Ischemic stroke makes up for 80% of cases. Each year, around 800,000 Americans experience a new or recurrent stroke, and it is the fifth leading cause of death in the U.S. Stroke affects the arteries leading to and inside of the brain, and it occurs when a blood vessel develops a clot or ruptures. Cell-based therapies are showing promise for the treatment of stroke.
How Stem Cells work in Treating Stroke
Stem cell therapy works for stroke by targeting the brain’s neural circuitry, which controls motor function. The cells travel to the brain lesions in attempt to promote repair and regeneration through secretion of cytokines and nerve growth factors. Improvements can be seen in 2-6 months in most patients. The results are permanent, and therapy should be used in conjunction with other rehabilitation. Improvements seen include: enhance posture, physical coordination, lower body movement, and speech; ability to stand; improve hand-eye coordination; increased overall muscle strength; and reduced muscle tension.
In some mice studies, laboratory rodents shown reduction of infarct lesion by 50% only two days after therapy. Stem cell therapy has been found to result in the upregulation of growth factors that could be responsible for outgrowth of endogenous fiber processes, as well as the inhibition of inflammatory processes. Stem cells in animal studies was found to induce reinstatement of functional connectivity as determined by MRI scans.
Clinical Studies involving Stem Cells
A group of researchers evaluated the effectiveness of stem cell therapy in 12 people with stroke. Human neuronal cells were transplanted. After six months, half of the participants had increased fluorodeoxyglucose at the site of transplantation. In addition, moderate improvement was noted. Another study was conducted involving intravenous stem cell therapy after stroke. After 12 months, symptom scores improved and the patients had no notable side effects.
A large study involving 52 people with ischemic stroke was conducted via observer-blinded trial. In the study, 12 people were treated with stem cells 1-4 months following stroke. The research team concluded that intravenous autologous MSCs were effective and safe for management of ischemic stroke. Another trial involving stem cells from umbilical cord blood showed significant improvement in transplanted patients compared to the control group.
A recent clinical trial involved intrathecal (into the space around the spinal cord) injection of stem cells in 26 patients with stroke. Improvement was seen in several indexes in the majority of participants, and researchers did not find any adverse effects. In addition, there has been other studies similar that proved safe for stroke patients. It appears adult stem cells are a good choice for stroke therapy because they secrete bioactive substances, such as growth factors, trophic factors, and cytokines.
A long-term safety and efficacy study involved MSC transplantation in a large sample of 85 patients. The patients were randomly allocated to one of two groups. Some received intravenous cultured stem cells, and others received a saline solution. The patients were followed for five years following the study. Of the patients, no side effects were observed, and clinical improvement was higher in the MSC treatment group. In addition, MSC therapy was associated with serum levels of stromal cell-derived factor 1.
Lee JS, Hong JM, Moon JM, et al. (2010). A Long-Term Follow-Up Study of Intravenous Autologous Mesenchymal Stem Cell Transplantation in Patients With Ischemic Stroke. Stem Cells, 28(6).
Patel AN, Park E, Kuzman M, Benetti F, Silva FJ, Allickson JG. Multipotent menstrual blood stromal stem cells: Isolation, characterization, and differentiation. Cell Transplant. 2008;17:303–11.
Rodrigues MC, Glover LE, Weinbren N, Rizzi JA, Ishikawa H, Shinozuka K, et al. Toward personalized cell therapies: Autologous menstrual blood cells for stroke. J Biomed Biotechnol. 2011;2011:194720.
Sanberg PR, Eve DJ, Willing AE, Garbuzova-Davis S, Tan J, Sanberg CD, et al. The treatment of neurodegenerative disorders using umbilical cord blood and menstrual blood-derived stem cells. Cell Transplant. 2011;20:85–94.
Yang QC, Zhang XD, Liang CC, Du Y, Li HW. Functional evaluation of stroke patients 6 months after intrathecal injection of neural stem cells. Chinese J Clin Rehabil. 2005;9:208–10.
Young-Bang O, Ki EH, Cha JM, & Moon GJ (2016).Adult Stem Cell Therapy for Stroke: Challenges and Progress. J Stroke, 18(3), 256-266.