Researchers at the Children’s Medical Center Research Institute at UT Southwestern Medical Center have found that mesenchymal stromal cells (MSCs) expressing leptin-receptors are the main source of bone and adipocytes formed in the adult bone marrow. The identification of such a biomarker opens up a door of possibilities for researchers to correctly identify and characterize the function of MSCs in the body, a subject of particular relevance, since there are almost 200 active clinical trials focusing on these cells for a broad range of conditions such as bone fractures, cartilage injury, degenerative disc disease, and osteoarthritis.
The team found that, in mice, approximately 0.3% of bone marrow cells expressed the leptin-receptor biomarker and that although normally quiescent, these cells proliferate after cirurgy to regenerate bone. Additionally, MSCs positive for the leptin-receptor are also the main source of factors responsible for the maintenance of blood-forming stem cells in the bone marrow.
Although the clinical interest in MSCs has increased over the last years, advances in this field have been slow partly because researchers were not able to accurately identify MSCs and study their physiological function in the body.
Dr. Sean Morrison, senior author of the study and holder of the Mary McDermott Cook Chair in Pediatric Genetics at UT Southwestern, stated that “unfortunately, many clinical trials that are testing potential therapies using MSCs have been hampered by the use of poorly characterized and impure collections of cultured cells.”
The team hopes to duplicate their findings with human MSCs, increasing the probability of success for clinical trials using such cells.
Dr. Bo Zhou, a postdoctoral research fellow in Dr. Sean Morrison’s laboratory, was the first author of this study, published in this months’ edition of the peer-reviewed journal Cell Stem Cell and funded by the National Heart, Lung, and Blood Institute, the Cancer Prevention and Research Institute of Texas, and donors to the Children’s Medical Center Foundation.