The SAGE Encyclopedia of Stem Cell Research. Группа авторов
Center for Regenerative Medicine (Cord Blood Registry, or CBR), which is known to be the world’s largest and most experienced stem cell bank. The trial will enroll 10 children ages 18 months to 17 years who have umbilical cord blood banked with CBR and have suffered moderate to severe TBI. This study is not designed for acute care and will only enroll participants within 6–18 months of their injury.
In order to enroll in the study, parents or caregivers of patients who have suffered a traumatic brain injury should contact CBR and after consent is obtained, the information will be relayed to the UTHealth research group. CBR helps by connecting the child and family with appropriate researchers and thus plays a significant role in the study. If all qualifications are met, the patient will travel to Children’s Memorial Hermann Hospital. The cells will be processed and intravenously infused. Patients will be followed at six months, one year, and two years. This study is considered to be the forefront of researches evaluating a juvenile’s own cord blood stem cells’ ability to help the healing process after TBI-induced damage to nerve tissue in the brain.
Three Theories Defining How Stem Cells Work in TBI
Up till now, there have been two widely held opinions on how stem cells can work to provide potential treatments for brain damage caused by injury or neurodegenerative disorders. One doctrine is that stem cells implanted into the site of injured brain tissue directly replace dead or dying cells. The other, more current view is that transplanted stem cells secrete growth factors that indirectly save the injured tissue.
In late 2013, University of South Florida (USF) researchers presented evidence for a third theory of stem cell mediated brain repair following trauma. In a series of preclinical experiments under principal investigator Professor Cesar Borlongan, who is also the director of the USF Center for Aging and Brain Repair, the team reported that transplanted stem cells appear to build a “biobridge” that links an undamaged intact brain site where new neural stem cells are born with the damaged injured region of the brain. According to the USF rsearchers, the transplanted stem cells serve as migratory signals for the brain’s own neurogenic cells, guiding the migration of these newly formed host cells from their neurogenic niche toward the injured brain tissue.
The researchers at USF indiscriminately assigned rats with TBI and confirmed neurological impairment to one of two groups. One group received transplants of SanBio Inc.’s bone marrow–derived stem cells (SB632 cells) into the region of the brain affected by traumatic injury. The other control group received a replica procedure in which solution alone was infused into the brain with no implantation of stem cells.
At one and three months post-TBI follow-up, the rats receiving stem cell transplants displayed considerably better motor and neurological function and reduced brain tissue damage compared to the control group rats receiving solution alone. These healthy improvements were observed even though the survival of the transplanted cells was modest and reduced over time.
The researchers then conducted a series of experiments to examine the host rats’ brain tissue. At three months post TBI, the brains of the rats transplanted with stem cells showed substantial cell proliferation and differentiation of stem cells into neuron-like cells in the area of injury. This was accompanied by a solid stream of stem cells migrating from the brain’s uninjured subventricular zone (SVZ), one of the two major stem cell niches in the brain, as described above, to the brain’s site of injury.
On the other hand, the rats receiving solution alone showed restricted proliferation and neural commitment of stem cells, with only dispersed migration to the site of brain injury and virtually no expression of newly formed cells in the SVZ. Without the addition of transplanted stem cells, the brain’s self-repair process appeared inadequately deficient to maintain a defense against the cascade of TBI-induced cell death. Based on the data reported by the USF researchers in this preclinical study, the FDA recently approved a limited clinical trial to transplant SB632 cells (an adult stem cell therapy) prepared by SanBio Inc. into patients with traumatic brain injury.
Syed A. Quadri
Desert Regional Medical Center, Palm Springs
Mudassir Farooqui
Aga Khan University Hospital
Atif Zafar
University of Iowa Hospitals and Clinics
Fahad Mehmood
Shariq Nawab
Dow University of Health Sciences
Muhammad Junaid Uddin Zaheer
Aga Khan University Hospital
See Also: Stem Cell Banking; Stem Cell Niche; University of Texas Health Science Center at Houston.
Further Readings
SanBio. http://www.san-bio.com (Accessed May 2014).
“Stem Cells.” National Institutes of Health. http://stemcells.nih.gov/info/basics/pages/basics4.aspx (Accessed May 2014).
Clinical Trials Outside the United States
Clinical Trials Outside the United States
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Clinical Trials Outside the United States
Although research utilizing stem cells is still nascent, the cumulative research endeavors around the world will eventually lead to new treatments for a variety of diseases. Stem cell research is any form of research that focuses on the regenerative abilities of stem cells as possible therapeutic interventions for a wide array of diseases. The research of most interest surrounds possible treatments for chronic and debilitating diseases that have for so long evaded the scope of medical therapies, such as diabetes mellitus, cardiovascular disease, diseases of the nervous system, and osteoarthritis. In this day and age, these diseases are manageable but lack an outright cure. Stem cell research is so vital because many of the illnesses that are being targeted are so prevalent around the world.
Diabetes
The World Health Organization (WHO) estimates that approximately 347 million people are currently afflicted with some form of diabetes. Diabetes is a disease that vastly diminishes the body’s ability to regulate blood sugar levels, in part due to a decrease in insulin production (type 1) or a metabolic disorder characterized by hyperglycemia in the context of insulin resistance and relative decrease in insulin (type 2).
The type 1 variant of the disease is not as easily managed. Since the body is unable to harness its own insulin reserves, external insulin must be administered daily. This administration can be in the form of an insulin pump or a hypodermic needle. The external insulin is derived from bacteria, which have been inserted with a gene to produce human insulin. These therapies are not a cure for the disease, however, and those with type 1 diabetes constantly struggle to maintain their glucose levels.
Type 2 diabetes is a chronic disease associated with a 10-year shorter life expectancy, partially due to the associated complications that include but are not limited to cardiovascular disease, stroke, lower-limb amputations, and damage to the blood vessels, eyes, kidneys, nerves, and other systems. Many lifestyle factors are associated with the development of type 2 diabetes, including obesity and overweight, sedentary lifestyle, stress, and poor diet. Current methods to circumvent the deleterious effects of the disease include a combination of diet, exercise, and weight loss. A sustained regimen of weight loss has shown signs of improved sensitivity of the tissues to insulin.
In order to gain a better understanding of the key role stem cells can play in the fight against diabetes, it is necessary to first provide a greater understanding of the physiology of the disease.