Health & Medicine
Fat-Forming Cells Help Aid Muscles After Injury
Kathleen Lees
First Posted: Apr 21, 2013 11:27 AM EDT
A recent study confirms that after eosinophils move to the shite of an injury, they actually collaborate with a kind of progenitor cell-immature cells similar to stem cells, and drive the formation of new muscle fibers.
The progenitors, called the fibro/adipogenic cells (FAP), don't spin off muscle cells directly. Researchers from the UCSF Cardiovascular Research Institute investigated just how this process worked, with insights from the lead investigator, Ajay Chawla, MD, PhD.
"Without eosinophils you cannot regenerate muscle," Chawla said, according to Science Daily.
FAP cells have been known for their role in fat making, which often occurs as the body ages or experiences prolonged immobility. They also have been known to create cells that form connective tissues. Yet the UCSF study showed that the FAP cells also join with the eosinophils to make injured muscles stronger through fat tissue when they are damaged, at least in mice, as shown in the study.
In a kind of cellular chain reaction, Chawla's team found that when eosinophils at the site of muscle injury secrete a molecule called IL-4, FAP cells respond by expanding their numbers. And instead of becoming fat cells, they act on the true muscle stem cells to trigger the regrowth of muscle fibers.
"They wake up the cells in muscle that divide and form muscle fibers," he said.
Eosinophils help fight bacteria and parasites, as do other immune cells, but eosinophils are more often thought of for their maladaptive roles in allergies and other inflammatory reactions. Eosinophils comprise only a few percent of immune cells.
"Eosinophils, acting via FAPs, are needed for the rapid clearance of necrotic debris, a process that is necessary for timely and complete regeneration of tissues," Chawla said.
Chawla's team found that, even before active muscle repair, the chain reaction initiated by eosinophils performs another necessary task -- taking out the garbage.
Bigger and more abundant immune cells called macrophages -- with large appetites and a propensity to gobble up debris in other destructive scenarios -- had often, but erroneously, been credited with cleaning up messes within distressed muscle tissue.
The National Institutes for Health and the California Institute for Regenerative Medicine funded the research, and the findings are published in April's issue of Cell.
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First Posted: Apr 21, 2013 11:27 AM EDT
A recent study confirms that after eosinophils move to the shite of an injury, they actually collaborate with a kind of progenitor cell-immature cells similar to stem cells, and drive the formation of new muscle fibers.
The progenitors, called the fibro/adipogenic cells (FAP), don't spin off muscle cells directly. Researchers from the UCSF Cardiovascular Research Institute investigated just how this process worked, with insights from the lead investigator, Ajay Chawla, MD, PhD.
"Without eosinophils you cannot regenerate muscle," Chawla said, according to Science Daily.
FAP cells have been known for their role in fat making, which often occurs as the body ages or experiences prolonged immobility. They also have been known to create cells that form connective tissues. Yet the UCSF study showed that the FAP cells also join with the eosinophils to make injured muscles stronger through fat tissue when they are damaged, at least in mice, as shown in the study.
In a kind of cellular chain reaction, Chawla's team found that when eosinophils at the site of muscle injury secrete a molecule called IL-4, FAP cells respond by expanding their numbers. And instead of becoming fat cells, they act on the true muscle stem cells to trigger the regrowth of muscle fibers.
"They wake up the cells in muscle that divide and form muscle fibers," he said.
Eosinophils help fight bacteria and parasites, as do other immune cells, but eosinophils are more often thought of for their maladaptive roles in allergies and other inflammatory reactions. Eosinophils comprise only a few percent of immune cells.
"Eosinophils, acting via FAPs, are needed for the rapid clearance of necrotic debris, a process that is necessary for timely and complete regeneration of tissues," Chawla said.
Chawla's team found that, even before active muscle repair, the chain reaction initiated by eosinophils performs another necessary task -- taking out the garbage.
Bigger and more abundant immune cells called macrophages -- with large appetites and a propensity to gobble up debris in other destructive scenarios -- had often, but erroneously, been credited with cleaning up messes within distressed muscle tissue.
The National Institutes for Health and the California Institute for Regenerative Medicine funded the research, and the findings are published in April's issue of Cell.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone