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nature.com
Fat cells boost blood vessel growth
Could liposuction left-overs help repair hearts?
5 March 2004
MICHAEL HOPKIN
Immature fat cells secrete molecules to boost blood vessel growth.
© Alamy.com
Fat is bad for your heart, right? Maybe not entirely, says a group of US researchers. The team claims that cells found in fatty tissues can boost blood-vessel production.
The discovery could pave the way for innovative treatments for conditions such as angina, in which narrowed arteries starve the heart of oxygen. Fat-derived cells could be injected close to the heart where they could form a new network of vessels, says Jalees Rehman of Indiana University School of Medicine, who led the study published online by the journal Circulation1. Liposuction patients could even find a use for their own unwanted blubber, he adds.
The cells could be injected wherever a patient needs them most, the researchers suggest. For someone with very poor circulation in their legs, for example, the treatment could avert the need for amputation.
Rehman's team injected immature fat cells, called stromal cells, into the hind legs of mice with poor circulation. The treatment boosted their blood flow fivefold.
The cells may work by secreting a nourishing cocktail of growth factors that promote blood vessel growth, explains Rehman. Cultured stromal cells release a protein called vascular endothelial growth factor. In turn this can recruit neighbouring cells to help form new veins and arteries.
Previous attempts to treat circulatory diseases with growth factors directly have failed. Rehman thinks that the cells, which secrete these molecules where and when they are most needed, offer a more sensitive solution. His team refers to them as "intelligent factories" for growth factors.
Liposuction leftovers
But can these diseases really by treated with the leftovers from liposuction? "When we tell people about it, they often say it sounds too simple to be true," Rehman admits.
The idea needs further study before it can enter doctors' therapeutic arsenal, says Adam Katz, a plastic surgeon at the University of Virginia. "There is a great deal more to learn about these cells before they can have clinical use," he warns. "I think there is a danger in rushing into things."
But treatments using fat cells are a hot topic of research, says Katz, especially as increasing numbers of people are carrying something of a surplus in that area. "No other tissue in the body is more abundant or expendable," he says.
It is already known that fat contains stem cells, which can give rise to a range of tissues including bone, muscle and cartilage2. The discovery led to liposuction being hailed as an alternative source of stem cells that would sidestep ethical worries over the use of fetal material.
Stromal and stem cells are both primitive cell types, but researchers are not sure whether they are the same, or subtly different. "The fact that different people use different names for them reflects the early stage of our understanding," comments Katz.
Although stromal cells may perhaps function as stem cells, Rehman says that their ability to recruit other cells, rather than simply dividing repeatedly to form new structures, could offer a more efficient way to build new blood vessels. "The body may have enough building blocks lying around already," he says.
References
Rehman, J. et al. Circulation, published online, doi:10.1161/01.CIR.0000121425.42966.F1 (2004). |Article|
Zuk, P. A. et al. Tissue Eng, 7, 211 - 228, (2004).
© Nature News Service / Macmillan Magazines Ltd 2004 |
