Adult stem cells improve fracture healing

June 16, 2008

In an approach that could become a new treatment for the 10 to 20 percent of people whose broken bones fail to heal, researchers at the University of North Carolina at Chapel Hill have shown that transplantation of adult stem cells can improve healing of fractures.

Adult stem cells are specialized cells with the ability to regenerate tissue in response to damage. However, many patients lack sufficient numbers of these cells and thus cannot heal properly.

Researchers have used adult stem cells in a few cases to improve fracture healing, but further studies were needed to show that this method was truly effective and safe before it can be pursued as a new treatment.

Now scientists at UNC have provided the scientific foundation for future clinical trials of this approach by demonstrating in animal models that these cells can be used to repair broken bones.

"This finding is critical to patients who lack the proper healing process and to individuals prone to broken bones, such as those with osteoporosis and the rare genetic condition known as brittle bone disease," said Dr. Anna Spagnoli, associate professor of pediatrics and biomedical engineering in the UNC School of Medicine and senior author on the study.

The study, presented Monday, June 16 at the annual Endocrine Society meeting in San Francisco by the first author, Froilan Granero-Molto, Ph.D., post-doctoral associate researcher in UNC's pediatrics department, is the first to visualize the action of transplanted adult stem cells as they mend fractures in mice.

During normal fracture healing, stem cells migrate to the site of the break, forming the cartilage and bone needed to fuse the broken bones back together. But in more than 600,000 Americans a year, this process does not occur as it should and these bones stay broken. The result can be long periods of immobilization, pain, bone deformities and even death.

Current therapies, such as multiple surgeries with bone autografts and artificial prosthetic materials, often are not enough to cure these patients.

"Man-made materials do not address the normal bone's function, and recurrent fractures, wear and toxicity are a real problem," Spagnoli said. "There is clearly a need to develop alternative therapies to enhance fracture healing in patients with bone union failure."

Kicking stem cells into repair mode is one of the objectives of a new branch of medicine called regenerative medicine. With a little prodding, stem cells in human bone marrow – called mesenchymal stem cells – can turn into bone, cartilage, fat, muscle and blood vessel cells.

"The beauty of regenerative medicine is that we are helping the body improve its innate ability to regenerate healthy tissue on its own, rather than introducing manmade materials to try to patch up a broken bone," Spagnoli said.

Granero-Molto and other colleagues led by Spagnoli demonstrated this approach by transplanting adult stem cells in mice with fractures of the tibia, the long bone of the leg. The cells were taken from the bone marrow of mice that produce luciferase, the same molecule that allows fireflies to glow. In addition to possessing the ability to glow, the cells were engineered to express a molecule called insulin-like growth factor 1 (IGF-1). IGF-1 is a potent bone regenerator necessary for bones to grow both in size and strength.

The researchers transplanted the cells through a simple intravenous injection and then placed the mice into a dark box so they could track the glowing stem cells as they migrated within the rodent. They found that these cells were specifically attracted to the fracture site, and that a particular molecule called CXCR4 – which acts as a homing signal – was necessary for the migration.

Using a computerized tomography (CT or CAT) scan, the researchers showed that the stem cells not only migrated to the site of the fracture, but also improved healing there by increasing the bone and cartilage that bridged the bone gap. The bone at the fracture site in the treated mice was about three times stronger than that of untreated controls.

If scientists can duplicate the results of this animal study in humans, it may lead to a new treatment for the millions of people who suffer fractures that do not heal properly, Spagnoli said. Once a physician determines that the bone has not healed, they could obtain adult stem cells from the person's bone marrow in a minimally invasive procedure and transplant them at the same time the patient is receiving a bone graft.

Spagnoli said adult stem cells may pose fewer problems than embryonic stem cells, since they are not associated with the ethical controversy that surrounds the latter. Also, they may avoid the problem of rejection by the immune system, since the patient's own cells can be used.

Source: University of North Carolina at Chapel Hill

Explore further: Bolstering fat cells offers potential new leukemia treatment

Related Stories

Bolstering fat cells offers potential new leukemia treatment

October 16, 2017
Killing cancer cells indirectly by powering up fat cells in the bone marrow could help acute myeloid leukemia patients, according to a new study from McMaster University.

Researchers describe mechanism that underlies age-associated bone loss

September 22, 2017
A major health problem in older people is age-associated osteoporosis—the thinning of bone and the loss of bone density that increases the risk of fractures. Often this is accompanied by an increase in fat cells in the ...

A new CRISPR-engineered cancer model to test therapeutics

October 5, 2017
One major challenge in cancer research is developing robust pre-clinical models for new therapies, ones that will accurately reflect a human response to a novel compound. All too often, a potential treatment that initially ...

Bone marrow protein a 'magnet' for passing prostate cancer cells

September 19, 2017
Scientists at the University of York have shown that a protein in the bone marrow acts like a 'magnetic docking station' for prostate cancer cells, helping them grow and spread outside of the prostate.

Umbilical cord stem cells show promise as heart failure treatment

September 26, 2017
A heart failure treatment using umbilical cord-derived stem cells may lead to notable improvements in heart muscle function and quality of life, according to a new study published in Circulation Research, an American Heart ...

Research redefines proteins' role in the development of spinal sensory cells

September 19, 2017
A recent study led by Samantha Butler at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA has overturned a common belief about how a certain class of proteins in the spinal cord regulate ...

Recommended for you

Inflammation trains the skin to heal faster

October 18, 2017
Scars may fade, but the skin remembers. New research from The Rockefeller University reveals that wounds or other harmful, inflammation-provoking experiences impart long-lasting memories to stem cells residing in the skin, ...

Large variety of microbial communities found to live along female reproductive tract

October 18, 2017
(Medical Xpress)—A large team of researchers from China (and one each from Norway and Denmark) has found that the female reproductive tract is host to a far richer microbial community than has been thought. In their paper ...

Study of what makes cells resistant to radiation could improve cancer treatments

October 18, 2017
A Johns Hopkins University biologist is part of a research team that has demonstrated a way to size up a cell's resistance to radiation, a step that could eventually help improve cancer treatments.

New approach helps rodents with spinal cord injury breathe on their own

October 17, 2017
One of the most severe consequences of spinal cord injury in the neck is losing the ability to control the diaphragm and breathe on one's own. Now, investigators show for the first time in laboratory models that two different ...

Pair of discoveries illuminate new paths to flu and anthrax treatments

October 17, 2017
Two recent studies led by biologists at the University of California San Diego have set the research groundwork for new avenues to treat influenza and anthrax poisoning.

New method to measure how drugs interact

October 17, 2017
Cancer, HIV and tuberculosis are among the many serious diseases that are frequently treated with combinations of three or more drugs, over months or even years. Developing the most effective therapies for such diseases requires ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.