ALS mice improved with stem cell therapy; first step for science in finding better treatment  

TAMPA, Fla. (May 12, 2017) – Researchers at the University of South Florida show in a new study that bone marrow stem cell transplants helped improve motor functions and nervous system conditions in mice with the disease amyotrophic lateral sclerosis (ALS) by repairing damage to the  blood-spinal cord barrier.

In a study recently published in the journal Scientific Reports, researchers in USF’s Center of Excellence for Aging and Brain Repair say the results of their experiment are an early step in pursuing stem cells for potential repair of the blood-spinal cord barrier, which has been identified as key in the development of ALS. USF Health Professor Svitlana Garbuzova-Davis, PhD, led the project.

Previous studies in development of various therapeutic approaches for ALS typically used pre-symptomatic mice. This is the first study advancing barrier repair that treats symptomatic mice, which more closely mirrors conditions for human patients, Dr. Garbuzova-Davis said.

Svitlana Garbuzova-Davis, PhD, led the study.

Using stem cells harvested from human bone marrow, researchers transplanted cells into mice modeling ALS and already showing disease symptoms. The transplanted stem cells differentiated and attached to vascular walls of many capillaries, beginning the process of blood-spinal cord barrier repair.

The stem cell treatment delayed the progression of the disease and led to improved motor function in the mice, as well as increased motor neuron cell survival, the study reported.

ALS is a progressive neurodegenerative disease that affects neuronal cells in the brain and the spinal cord, which send signals to control muscles throughout the body. The progressive degeneration of motor neuron cells leads to death from ALS. More than 6,000 Americans each year are diagnosed with the disease.

Because stem cells have the ability to develop into many different cell types in the body, researchers at USF’s Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Brain Repair have focused on using stem cells to restore function lost through neurodegenerative disorders or injuries.

Damage to the barrier between the blood circulatory system and the central nervous system has been recently recognized as a factor in ALS development, leading researchers to work on targeting the barrier for repair as a potential strategy for ALS therapy.

In this study, the ALS mice were given intravenous treatments of one of three different doses of the bone marrow stem cells. Four weeks after treatment, the scientists determined improved motor function and enhanced motor neuron survival. The mice receiving the higher doses of stem cells fared better in the study, the researcher noted.

The transplanted stem cells had differentiated into endothelial cells – which form the inner lining of a blood vessel, providing a barrier between blood and spinal cord tissue – and attached to capillaries in the spinal cord. Furthermore, the researchers observed reductions in activated glial cells, which contribute to inflammatory processes in ALS.

USF Health Morsani College of Medicine researchers Crupa Kurien, Avery Thomson, Dimitri Falco, Sohaib Ahmad, Joseph Staffetti, George Steiner, Sophia Abraham, Greeshma James, Ajay Mahendrasah, Paul R. Sanberg and Cesario V. Borlongan joined in the project. The study was funded by the National Institutes of Health, National Institute of Neurological Disorders and Stroke.

Read the full study here.

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News release by Vickie Chachere, USF Research and Innovation

Media contact: 
Anne DeLotto Baier, USF Health Communications
abaier@health.usf.edu or (813) 974-3303

University of South Florida researchers have suggested a new view of how stem cells may help repair the brain following trauma. In a series of preclinical experiments, they report that transplanted cells appear to build a “biobridge” that links an uninjured brain site where new neural stem cells are born with the damaged region of the brain.

Their findings were recently reported online in the peer-reviewed journal PLOS ONE.

“The transplanted stem cells serve as migratory cues for the brain’s own neurogenic cells, guiding the exodus of these newly formed host cells from their neurogenic niche towards the injured brain tissue,” said principal investigator Cesar Borlongan, PhD, professor and director of the USF Center for Aging and Brain Repair.

A team led by Cesar Borlongan, director of the University of South Florida Center for Aging and Brain Repair, offers a new concept for how transplanted stem cells help prod the brain’s own repair mechanism following traumatic brain injury.

Based in part on the data reported by the USF researchers in this preclinical study, the U.S. Food and Drug Administration recently approved a limited clinical trial to transplant SanBio Inc’s SB632 cells (an adult stem cell therapy) in patients with traumatic brain injury.

Stem cells are undifferentiated, or blank, cells with the potential to give rise to many different cell types that carry out different functions. While the stem cells in adult bone marrow or umbilical cord blood tend to develop into the cells that make up the organ system from which they originated, these multipotent stem cells can be manipulated to take on the characteristics of neural cells.

To date, there have been two widely-held views on how stem cells may work to provide potential treatments for brain damage caused by injury or neurodegenerative disorders.  One school of thought is that stem cells implanted into the brain directly replace dead or dying cells.  The other, more recent view is that transplanted stem cells secrete growth factors that indirectly rescue the injured tissue.

The USF study presents evidence for a third concept of stem-cell mediated brain repair.

The researchers randomly assigned rats with traumatic brain injury and confirmed neurological impairment to one of two groups. One group received transplants of bone marrow-derived stem cells (SB632 cells) into the region of the brain affected by traumatic injury. The other (control group) received a sham procedure in which solution alone was infused into the brain with no implantation of stem cells.

At one and three months post-TBI, the rats receiving stem cell transplants showed significantly better motor and neurological function and reduced brain tissue damage compared to rats receiving no stem cells. These robust improvements were observed even though survival of the transplanted cells was modest and diminished over time.

The researchers then conducted a series of experiments to examine the host brain tissue.

At three months post-traumatic brain injury, the brains of transplanted rats showed massive cell proliferation and differentiation of stem cells into neuron-like cells in the area of injury, the researchers found. This was accompanied by a solid stream of stem cells migrating from the brain’s uninjured subventricular zone — a region where many new stem cells are formed – to the brain’s site of injury.

In contrast, the rats receiving solution alone showed limited proliferation and neural-commitment of stem cells, with only scattered migration to the site of brain injury and virtually no expression of newly formed cells in the subventricular zone. Without the addition of transplanted stem cells, the brain’s self-repair process appeared insufficient to mount a defense against the cascade of traumatic brain injury-induced cell death.

The researchers conclude that the transplanted stem cells create a neurovascular matrix that bridges the long-distance gap between the region in the brain where host neural stem cells arise and the site of injury. This pathway, or “biobridge,” ferries the newly emerging host cells to the specific place in the brain in need of repair, helping promote functional recovery from traumatic brain injury.

Article citation:
“Stem Cell Recruitment of Newly Formed Host Cells via a Successful Seduction? Filling the Gap between Neurogenic Niche and Injured Brain Site;”  Naoki Tajiri, Yuji Kaneko, Kazutaka Shinozuka, Hiroto Ishikawa, Ernest Yankee, Michael McGrogan, Casey Case, and Cesar V. Borlongan; PLOS ONE 8(9): e74857.  Published Sept. 4, 2013.