🦴 This protein would affect men's bones (but not women's)

According to a recent study, the liver may play a previously unrecognized role in bone health, but only in men.

The study conducted at McGill University and published in Matrix Biology revealed that a protein produced in the liver helped regulate bone growth in male mice, but not in female mice. This finding could explain why men with liver disease are more likely to suffer from bone loss.

This protein, plasma fibronectin, is naturally present in the blood in greater quantity in men than in women, its concentration decreases when the liver is damaged, and it accumulates in bones to modulate bone formation. Thus, men would depend more on this protein than women for maintaining their bone strength.

"Approximately 60% of osteoporosis cases in men are linked to underlying health problems," says Mari Tuulia Kaartinen, Associate Professor in the Faculty of Dental Medicine and Oral Health Sciences at McGill University and senior author of the study. "Our findings suggest that this protein could be one of the biological links between liver disease and bone loss."

A mechanism that differs by sex

Osteoporosis has always been considered an aging-related disease and linked to internal bone processes, and it is more frequently associated with women. At least one in three women and one in five men will suffer an osteoporosis-related fracture during their lifetime.

"We know that women lose bone mass largely due to hormonal changes related to menopause, but men lose it too, especially after age 50, but it's not exactly known why," explains Professor Mari Tuulia Kaartinen.

During laboratory experiments, the research team deactivated the fibronectin gene in the liver, thereby preventing the protein from being released into the blood. Without this protein, bone strength tended to be lower in male mice.

"Here is another example showing that diseases can develop differently depending on sex," specifies Mari Tuulia Kaartinen. "It is essential to better account for biological differences in medical research to define more precise approaches for prevention and care."

More broadly, the study supports the increasingly prevalent hypothesis that osteoporosis is not a condition that affects only the bones, but the entire body, she adds.