Nine times stronger
A new study will help women strengthen bones and preserve them in old age
Dmitry Mazalevsky, Naked Science
More than 200 million people worldwide suffer from osteoporosis. In healthy people, bone tissue is constantly recycled, the old tissue is destroyed and replaced with a new one, but with age this cycle leads to loss of bone mass, as a result of which our bones become more fragile.
According to a study conducted by researchers at the University of California, San Francisco and Los Angeles, some brain cells may play a special role in controlling bone density in women. In a study published in the journal Nature Communications, scientists have shown that the removal of estrogen receptors in the hypothalamus neurons causes female mice to create unusually strong bones and preserve them as they age, which gives hope for new approaches to the prevention and treatment of osteoporosis in older women.
"Our colleagues, who have been studying skeletons all their lives, said they had never seen such strong bones. Today's understanding of how the body controls bone growth cannot explain this, which suggests that we may have found a completely new way that can be used to improve bone strength in older women and other people with fragile bones," says senior author of the study Holly Ingraham.
Women are at particularly high risk of osteoporosis after menopause due to a decrease in the level of estrogen, a sex hormone that usually promotes bone growth. Estrogen plays an important role in the female body, especially in the regulation of reproduction, but its function in the brain is still poorly understood.
A mouse bone sample from the control (left) and experimental group aged about 1.5 years. A snapshot from the UCSF Ultra-Sturdy Bones press release, with a Surprising Origin, Suggests a New Osteoporosis Approach - VM.
The study by California scientists began with the discovery that the genetic removal of the estrogen receptor protein in the hypothalamus neurons causes animals to gain weight and become less active. To detect the source of the extra weight, they decided to use an ultra-sensitive laboratory technique that also detected changes in bone density. To the surprise of the researchers, it really turned out to be bone tissue: the mass of animal bones increased by 800 percent. In addition, the bones of the mice became very hard. According to Ingraham, when her staff decided to test the strength of the fabric by trying to crush them, the equipment almost failed.
It is noteworthy that this works exclusively with female mice, and interference with the arcuate transmission of estrogen signals in males does not seem to have any effect. According to Ingraham, most neuroscientists in their research are limited to male mice, and only a few study estrogen, which may explain why this discovery has not been made before. Further experiments showed that genetically modified animals retained increased bone density until old age. Usually female mice begin to lose bone mass by the age of 20 weeks, but these animals retained weight during the second year of life - by mouse standards, this is quite an old age.
It is also interesting that scientists were able to reverse the existing bone degeneration in an experimental model of osteoporosis. In female mice that had already lost more than 70 percent of bone density due to experimentally reduced estrogen levels in the blood, removal of the estrogen arc receptors led to the fact that within a few weeks bone density was restored by 50 percent.
At the moment, researchers are investigating exactly how this interaction between the brain and bones occurs, and the results of their research will help in the development of drugs to increase bone strength in postmenopausal women without dangerous side effects.
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