The sticky substance secreted by the cells could actually be a natural scaffold for tissue growth, according to Deepak Nagrath, an Indian-origin researcher at the Rice University.
The substance, derived from adipose cells-body fat-turned out to be a natural extracellular matrix.
"I thought it was contamination, so I threw the plates away," said Nagrath.
And since then, Nagrath and his colleagues have built a biological scaffold that allows cells to grow and mature.
He hopes the new material, when suffused with stem cells, will someday be injected into the human body, where it can repair tissues of many types without fear of rejection.
And the basic idea is simple-prompt fat cells to secrete what bioengineers call "basement membrane."
The membrane mimics the architecture tissues naturally use in cell growth, literally a framework to which cells attach while they form a network.
When the cells have matured into the desired tissue, they secrete another substance that breaks down and destroys the scaffold.
Structures that support the growth of living cells into tissues are highly valuable to pharmaceutical companies for testing drugs in vitro. Companies commonly use Matrigel, a protein mixture secreted by mouse cancer cells, but for that reason it can't be injected into patients.
"Fat is one thing that is in excess in the body. We can always lose it," said Nagrath.
The substance derived from the secretions, called Adipogel, has proven effective for growing hepatocytes, the primary liver cells often used for pharmaceutical testing.
"My approach is to force the cells to secrete a natural matrix," he said.
The matrix is a honey-like gel that retains the natural growth factors, cytokines and hormones in the original tissue.
Nagrath is convinced that his strategy is ultimately the most practical for rebuilding tissue in vivo, and not only because it may cost significantly less than Matrigel.
"The short-term goal is to use this as a feeder layer for human embryonic stem cells. It's very hard to maintain them in the pluripotent state, where they keep dividing and are self-renewing," he said.
Once that goal is achieved, Adipogel may be just the ticket for transplanting cells to repair organs.
"You can use this matrix as an adipogenic scaffold for stem cells and transplant it into the body where an organ is damaged. Then, we hope, these cells and the Adipogel can take over and improve their functionality," said Nagrath.
The research appeared last week in the Federation of American Societies for Experimental Biology (FASEB) Journal.