Fracture healing is a problem that affects an estimated 600,000 people annually in North America [1]. This problem can be caused by diseases such as , brittle bone disease and osteoporosis. Researchers at the University of North Carolina School of Medicine studied the effects of mesenchymal stem cells (MSCs) on bone fractures in mice [1].

The researchers engineered mice MSCs to express insulin-like growth factor-1 (IGF-I) then transplanted the treated cells into mice with non-union fractures. Computed tomography scanning showed that the mice treated with MSCs expressing IGF-I experienced faster healing than the control group and the mice treated with only MSCs. The new bone was shown to be three or four times stronger, and more bone bridging the fracture gap than the control group.

A similar study was done by Dr. Richard Kremer at McGill University Health Care. First, mesenchymal stem cells were cultured to turn into osteoblasts in-vitro and it was found that the differentiation process involved interferon (IFN) gamma-related genes [2]. In order to study the involvement of IFN gamma-related genes, they moved to an animal model where the IFN gamma effect was blocked by inactivating its receptor. Blocking this effect caused significantly lower bone mass than their healthy counterparts. Their MSCs also showed a decreased ability to make bone, confirming that IFN gamma is an integral factor for MSCs differentiation into osteoblasts. These findings suggest that IFN gamma, or another molecule involved in its pathway could become a treatment for osteoporosis.

Researchers from the University of California, Davis Health System have engineered a molecule, LLP2A-alendronate, that when injected into the bloodstream prompts indigenous stem cells to travel to the surface of bones and differentiate into osteoblasts [3]. LLP2A-alendronate is a hybrid molecule that consists of the LLP2A part that attaches to the MSCs in the bone marrow, and a second part that consists of the bone-homing drug, alendronate [4]. This molecule was tested on mice and showed evidence of reducing the signs of osteoporosis, holding major promise for the development of new drugs to treat this disease. This technique directs a person’s endogenous MSCs to the bone surface so that they can regenerate bones.

MSCs can be used to speed the healing of non-union fractures and strengthen bones through the use of different protein signals and molecules. The most effective way to signal MSCs to repair bones is currently undergoing research. These studies show potential for the development of new drugs to treat osteoporosis.

Vitro Biopharma has recently launched its initial line of osteoblasts derived from human MSCs for use in drug discovery and development. These products enable researchers to conduct various cellular assays to assist in development of novel therapies of bone degenerative diseases and accelerated recovery of fractured bones.

 

Contributed by Lianne Nelsen, Research Technician, Vitro Biopharma & Chemical Engineering student at the Colorado School of Mines.

 

[1] Lang, Les. 6 Jun 2011. “Stem cell treatment may offer option for broken bones that don’t heal.” Web.  <http://www.med.unc.edu/www/newsarchive/2011/june/stem-cell-treatment-may-offer-option-for-broken-bones-that-don2019t-heal>

[2] “Stem cells could halt osteoporosis, promote bone growth MUHC team describes a new pathway that controls bone remodeling.” 4 Mar 2009.  Web. <http://muhc.ca/newsroom/news/stem-cells-could-halt-osteoporosis-promote-bone-growth-muhc-team-describes-new-pathway-controls>

[3] “Study uses stem cells to treat osteoporosis.” Web.  <http://www.canadianpharmacymeds.com/news/study-uses-stem-cells-to-treat-osteoporosis–800702652>

[4] “UC Davis investigators develop method of directing stem cells to increase bone formation and bone strength.” 6 Feb 2012. Web. <www.ucdmc.ucdavis.edu/publish/news>