World First: The healing power of ‘happy fat’

15 March 2011

The ability to initiate muscle regeneration — to enable the body to create healthy, new tissue — is both a scientific and medical holy grail. The clinical applications could dramatically improve the quality of life for people suffering from chronic degenerative diseases. It's this quest that drives Dr. Fabio Rossi, MSFHR 2004 Career Investigator and Canada Research Chair in regenerative medicine, and has led him to several important discoveries including a previously unknown cell that could unlock the process of tissue regeneration.

"Until we started our research, there was no indication of where the cells that made the scar tissue came from," says Rossi. "Our research found cells that were excellent candidates."

These cells — called fibro/adipogenic progenitors (FAPs) — are often filled with fat, and can also make new fat that is embedded in the fibrous tissue. They are present throughout the body. In fact, they are the same cells that make new fat when we gain weight.

"When you gain weight, there are two mechanisms at play — the first is that the existing fat cells become larger, and the second is that the cells make new fat cells," he says. The second mechanism is good; the first is bad. While large fat cells become dysfunctional and lead to disease, small fat cells remain "happy."

The level of inflammation that develops in damaged muscle determines whether FAP cells die or multiply. Rossi's team discovered that FAP cells become activated before the muscle-making stem cells and that these two types of cells interact to direct the stem cells' function.

"If everything goes well, the muscle-making stem cells send a signal to the FAPs, which then die," says Rossi. But if the muscle-making stem cells do not have the situation in hand, the signal is not sent, the FAP cells don't die, and they form a fibrous scar.

To translate this information to clinical practice, Rossi is working to determine how the signalling works between the cell types. "We need to really understand how the cells coordinate their actions by talking to each other so that we can modify the messages," he says.

Understanding this cellular talk could lead to the development of therapies that enable humans to regenerate tissue.

"That's the long-term goal — to regulate the process so the scar-making cells don't take over," says Rossi.

Rossi's research on scar tissue and FAP cells is one of many noteworthy achievements of MSFHR Career Investigators identified in a new report that analyses MSFHR's Career Investigator Program and its contribution to building BC's health research capacity.