According to the researchers: use of an antidepressant can prevent osteoporosis
In the photo: the research team (from right to left) Prof. Itai Bab, Prof. Esther Shahmi and Prof. Raz Yeremia. Photo courtesy of the Hebrew University.
Researchers from the Hebrew University discovered that depression plays a crucial role in the decrease in bone density that causes osteoporosis and fractures. The research findings are of great importance in understanding the mechanisms linking the brain and the skeleton. Based on the findings, the effectiveness of using antidepressants to prevent bone loss has already been demonstrated. An article about their research will be published today, October 30, in the prestigious American journal PNAS (Proceedings of the National Academy of Sciences).
Osteoporosis is the most common degenerative disease in Western society. A decrease in bone density is the main cause of bone fractures and osteoporosis, which mainly women suffer from, after the cessation of the menstrual cycle. The disease affects one in four women over the age of 55, and it is estimated that more than one-third of women and one-sixth of men will suffer at least one osteoporotic crisis during their lifetime. Fractures of this type can lead to death in more than ten percent of cases and reduce the long-term quality of life for half of the people who survive.
The research is part of a project designed to find out the connection between the brain, mental states and changes in the structure of the skeleton. This research serves as a basis for the development of new and effective drugs for osteoporosis. On the basis of the research findings, the company "Yishom", the research development company of the Hebrew University, submitted an application for registration of a patent for the treatment of osteoporosis with the help of antidepressants.
The research group includes researchers from the Brain and Behavior Laboratory led by Prof. Raz Yeremia, from the Department of Psychology at the Hebrew University; Researchers from the bone laboratory headed by Prof. Itai Bab, from the school of dentistry at the university; and researchers from the brain trauma research laboratory led by Prof. Esther Shehami, from the school of pharmacy at the university. Doctoral students Inbal Goshen, Alon Bejaio, Tertzah Kreisel, Sharon Feldman and Yosef Tam also participated in the research.
To test the relationship between depression and bone loss, the researchers used a model for depression, caused by exposure of laboratory mice to mild chronic stress. Similar to the effect of depression on humans, a depression-like state in mice is characterized by a reduction in hedonic behavior and social interaction. Animals that were depressed for four weeks showed a dramatic decrease in bone density, including the density of the femur bones and the vertebral bones. The bone depletion is caused by a disruption in the process of bone regeneration which is essential for maintaining normal bone density. The disorder occurred following a reduction in the number of bone-building cells, called osteoblasts. Chronic treatment with the antidepressant drug imipramine (tofernil) resulted not only in the prevention of the behavioral depressive state but also in halting the decrease in bone density.
The researchers even characterized a neural pathway linking the state of depression to bones. They found that depression activates a nervous system that connects the brain and internal organs, including the skeleton. This system is called the "sympathetic nervous system". Its activation causes the release of a chemical in the bones called norepinephrine, which affects the bone-building cells. The researchers found that treatment with a drug that inhibits the activity of norepinephrine actually blocks the harmful effect of depression on the bone, although it does not prevent the behavioral depressive state.
"The relationship between the brain and bone in general, and the effect of depression on bone density in particular, is a new field of research and very little is known about it," says Prof. Raz Yeremia. "The new findings discovered in the laboratories of the Hebrew University point for the first time to depression as an important risk factor for bone loss and osteoporosis."
According to Prof. Babb, "Together with other studies published in the last year by our research group, this study defines a new scientific field that we call 'neuro-psycho-osteology'. This field of research deals with the connections between the brain, the mental state and the skeleton."
The research is funded by the "Bikura" program of the Israel National Science Foundation, which supports unique topics and pioneering multidisciplinary projects.
