Osteoporosis is a disease in which bones become fragile and more likely to break. If left untreated, osteoporosis can progress painlessly until a bone fractures in the hip, spine and wrist. According to the World Health Organization, osteoporosis affects one in four women over the age of 50.
Interferon gamma (IFN) is a hormone produced by our own bodies, and is a strong inhibitor of osteoclast differentiation and activity and holds great promise to repair bones affected by osteoporosis.
Researchers have found that manipulating mesenchymal stem cells (MSCs) with IFN gamma could promote bone growth.
“We have identified a new pathway, centered on IFN gamma, that controls the bone remodeling process both in-vivo and in-vitro,” explains Dr. Richard Kremer, the study’s lead author. “More studies are required to describe it more precisely, but we are hopeful that it could lead to a better understanding of the underlying causes of osteoporosis, as well as to innovative treatments.”
“First, we stimulated cultured MSCs to turn into bone cells (osteoblasts) in-vitro,” says Dr Kremer. “We realized that this differentiation process involved IFN gamma-related genes, but also that these bone cells precursors could both be stimulated by IFN gamma and produced IFN gamma.”
The next step was to move to an animal model where IFN gamma effect is blocked by inactivating its receptor, a model called IFN gamma receptor knock-out. Bone density tests, comparable to those used to diagnose people with osteoporosis, were conducted. The results revealed that these animals have significantly lower bone mass than their healthy counterparts. In addition, their MSCs have a decreased ability to make bone. “These findings confirm that IFN gamma is an integral factor for MSCs differentiation into osteoblasts also in-vivo,” says Dr. Kremer.
Both in-vitro and in-vivo results proved that IFN gamma is key to the differentiation of MSCs into bone cells, and to growth process of the bone. The exact pathway by which IFN acts on bone cells’ formation will require more research to be described, but the strict correlation highlighted in this study leaves no doubt on its importance.
1. Richard Kremer, et al. Autocrine Regulation of Interferon Gamma in Mesenchymal Stem Cells Plays a Role in Early Osteoblastogenesis. Stem Cells, doi:10.1634/stemcells.2008-0886.