A molecular pathway that connects the growth of hair across the human body could be key to future cosmetic treatments of baldness and unwanted growth, according to a new study.

The mouse model showed how different regions of hair are connected by the Wnt signaling pathway and bone morphogenetic proteins (BMP), according to the scientists from University of California, Irvine.

The two factors were previously connected to hair growth in isolated areas – but the latest breakthrough described in the journal eLife describes mathematical models that show the effects extend across all parts of the skin.

“In analogy with languages spoken in two neighboring countries, it was unclear how the back skin ‘talks’ with the belly skin to coordinate the tasks of growing hairs,” said Maksim Plikus, one of the authors, an assistant professor of developmental and cell biology. “We showed that although different signaling ‘dialects’ may exist between belly and back skin,  for instance, all hair can understand one another through the use of similar ‘words’ and ‘sentences.’”

The “language” between the hairs regulates growth by dictating the push-pull between Wnt and BMP. But if there is a breakdown in the communication, hairs function independently – either growing too much or not enough.

In male pattern baldness, for instance, the hair at the front and crown of the head loses the connection – but not the back of the head.

They discovered the relative levels of the two factors through complex mathematical modeling, provided by the laboratory of Qing Nie, a mathematics professor at UC-Irvine.

The theory: the communication pathway can be activated pharmacologically to keep the coordination between the follicles.

“If communication between nonbalding and balding regions can be reactivated, hair growth signals can then start spreading across the entire head skin, preventing regional baldness,” said Plikus, in a school statement.