Hormone found that would strengthen bone density

MADRID (EFE).— A team of American scientists has discovered a hormone that strengthens and keeps the bones of lactating women strong.

The discovery could help heal bone fractures and treat osteoporosis, which affects more than 200 million people worldwide.

The team, made up of researchers from the University of California in San Francisco and Davis, demonstrated in an experiment with mice that this hormone, known as maternal brain hormone (CCN3), increases bone density and strength.

The study, details of which were published yesterday in the journal Nature, uncovered the reason why women’s bones remained robust during breastfeeding, even as calcium is drawn from the bones during that stage.

In fact, “if we hadn’t studied female mice, which is unfortunately the norm in biomedical research, we might have missed this discovery,” warns Holly Ingraham, senior author of the paper and professor of cellular molecular pharmacology at San Francisco.

For this reason, among others, this study “underlines how important it is to observe both males and females throughout life to obtain a complete understanding of biology,” he said.

More than 200 million people worldwide suffer from osteoporosis, a serious weakening of the bones that can lead to frequent fractures.

Women are at high risk of osteoporosis after menopause due to decreased levels of estrogen, which promotes bone formation.

But although estrogen levels are also low during lactation, osteoporosis and bone fractures are much rarer during this period, suggesting that there were other factors that promote bone growth.

In previous studies, Ingraham’s lab found that female mice achieved specific increases in bone mass, and although they suspected a blood hormone was responsible for the super-strong bones, they couldn’t find it.

In the new work, Ingraham and her colleagues conducted an exhaustive search for this bone-strengthening hormone and ultimately pinpointed CCN3 as the factor responsible in the mutant females.

At first, the team was surprised by this result, since CCN3 did not fit the typical profile of a hormone secreted by neurons.

Their doubts were dispelled after finding CCN3 in the same brain region in lactating female mice.

Without CCN3 production in these selected neurons, lactating mice rapidly lost bone mass and their offspring began to lose weight, confirming the importance of the hormone in maintaining bone health during lactation.

Since its discovery, CCN3 has been called maternal brain hormone (MBH).

Tests with old male mice.

By applying strategies to increase circulating CCN3 in young adult and older female or male mice, their bone mass and strength increased over the course of weeks.

In some female mice that were completely lacking estrogen or were very old, CCN3 was able to more than double bone mass.

Researchers plan to conduct future studies on the molecular mechanisms of CCN3, its levels in lactating women, as well as the hormone’s potential to treat various bone conditions.

“Bone loss occurs not only in postmenopausal women, but also in breast cancer survivors taking certain hormone-blocking drugs, in younger, highly trained elite athletes, and in older men whose relative survival rate is lower than that of women after a hip fracture,” Ingraham explains.

“It would be incredibly exciting if CCN3 could increase bone mass in all of these scenarios,” he concludes.