Stem Cell Therapy Repairs Brain Damage Hours After Stroke Occurs

According to the Center for Disease Control, stroke is a leading cause of death in the United States. Fortunately stroke has been the subject of significant research efforts, but unfortunately, developing treatments that ensure complete recovery for stroke patients is extremely challenging. The challenge increase when more than a few hours have passed between onset of the stroke and administration of treatment.

Thus a new study released in STEM CELLS Translational Medicine has generated more than a little excitement. This study indicates that indicates that endothelial precursor cells (EPCs), which are found in the bone marrow, umbilical cord blood, and rarely in peripheral blood, can make a significant difference for these patients’ recovery. The contribution of EPCs even extends to the later stages of stroke. In animal studies, EPC implantation into the brain after a stroke minimized the initial brain injury and helped repair the stroke damage.

“Previous studies indicated that stem/progenitor cells derived from human umbilical cord blood (hUCB) improved functional recovery in stroke models,” noted Branislava Janic, Ph.D., a member of Henry Ford Health System’s Cellular and Molecular Imaging Laboratory in Detroit and lead author of the study. “We wanted to examine the effect of hUCB-derived AC133+ endothelial progenitor cells (EPCs) on stroke development and resolution in rats.”

Dr. Janic and his team injected EPCs into the brains of rats that had suffered strokes. When they later examined the animals using MRI, they found that the transplanted EPCs had selectively migrated to the injured area, stopped the tissue damage from spreading, initiated regeneration, and affected the time course for stroke resolution. The lesion size in the brain was significantly decreased at a dose of 10 million cells, if the cells were given as early as seven days after the onset of the stroke.

“This led us to conclude that cord blood-derived EPCs can significantly contribute to developing more effective treatments that allow broader time period for intervention, minimize the initial brain injury and help repair the damage in later post-stroke phases,” Dr. Janic said.

“The early signs of stroke are often unrecognized, and many patients cannot take advantage of clot-busting treatments within the required few hours after stroke onset,” said Anthony Atala, M.D., editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “In this animal study, a combination of stem cells shows promise for healing stroke damage when administered 24 hours after the stroke.”

Stem Cells Heal Damaged Baboon Arteries in the Lab

A research group at the Texas Biomedical Research Institute in San Antonio, Texas has reprogrammed embryonic stem cells derived from baboon embryos to completely restore a severely damaged artery. Such results lay the ground work for what might be a new way to completely heal large blood vessels that have been damaged by congenital diseases, the ravages of disease, or simply old age.

John L. VandeBerg, chief scientific officer at the Texas Biomedical Research Institute, said: “We first cultured the stem cells in Petri dishes (culture dishes) under special conditions to make them differentiate into cells that are the precursors of blood vessels, and we saw that we could get them to form tubular and branching structures, similar to blood vessels.”

Since VandeBerg and his colleagues were able to differentiate baboon embryonic stem cells into blood vessel precursors, they wanted to try a much more difficult experiment and try to use these blood vessels precursor cells to repair a damaged blood vessel in a simulated environment.

By removing the cells that line the inside of a baboon artery, VandeBerg and co-workers replaced the lining with the blood vessel precursors derived from baboon embryonic stem cells. Then they connected this artery segment to a plastic tubing inside a device known as a “bioreactor.” Bioreactors are designed to grow cells and tissues under conditions that closely mimic those inside the human body. In this case, the bioreactor also pumped fluid through it as though it were inside a real, living baboon.

The artery was bathed in culture medium, and by three days, the complex inner layer of the artery showed signs of regenerating, and by 14 days, it was perfectly restored to its complex, natural state. In two weeks, the artery had gone from stripped to a fully functioning artery.

VandeBerg said of these experiments: “Just think of what this kind of treatment would mean to a patient who had just suffered a heart attack as a consequence of a damaged coronary artery. And this is the real potential of stem cells regenerative medicine – that is, a treatment with stem cells that regenerates a damaged or destroyed tissue or organ.”

A control experiment also showed that the arteries could not regenerate without the added cell stems, they used an artery that can been internally stripped and hooked it up to the bioreactor without seeding it with stem cells. Under these conditions, no healing occurred.

When the arteries were stained for those proteins normally found in a properly functioning artery, the healed artery showed all the same staining characteristics as arteries that had not been internally stripped. Of this result, VandeBerg noted: “This is evidence that we can harness stem cells to treat the gravest of arterial injuries.”

Researchers such as Vandeberg hope to take a skin cell or a white blood cell, or a cell from just about anywhere else in the body and induce it to differentiate into induced pluripotent stem cells that can be used to differentiate into blood vessel precursors that can be used to repair damaged blood vessels.