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A replacement heart valve that expands as a child grows is one of Kristi Anseth's engineering aims.
Rebecca Richards-Kortum, an HHMI professor and biomedical engineer at Rice University, sees science and engineering along a spectrum. “At one end, there is pure science, where we just want to understand how the world works, and at the other is pure engineering where we just want to solve a problem like 'I need a rapid test for HIV that's 99 percent accurate and costs less than a dollar.'” There's a lot of overlap among individual researchers, she says.
HHMI investigator Kristi Anseth has at the root of all her endeavors a fundamental question: how does a cell get information from its surrounding environment? But she has ambitious practical applications for her findings.
“I want to design materials that I can use to culture cells”—cells for use in reconstructing damaged tissues, such as knees and hearts, says the chemical engineer at the University of Colorado at Boulder.
It is not yet possible to grow new tissues in a dish. A bit of structural engineering is necessary. Anseth creates an artificial scaffold that supports cells from her patients while delivering the proper molecules to encourage growth. The crux of the problem is figuring out what signaling molecules are needed—and the answer varies, depending on the tissue being regenerated.
According to Anseth, with such a complex subject, it's easy to get overwhelmed. “You can't understand every pathway within the cell, let alone what happens to that cell when it interacts with other cells,” she says.
She uses her engineer's training to reduce the scope of the problem. “I look at a complicated problem where we don't have enough information,” she says, “and I try to figure out what's the critical information, and make a judgment that's 90 percent correct.” In most cases, Anseth says, that approach is enough to learn what she needs and move forward. In one project, she is building a replacement heart valve for children with congenital valve defects. “There's no good option for them right now,” she says. “Most treatments require many surgeries because the children are growing so fast. If we could create a living, reengineered valve structure that could grow with a child, that would have lots of benefits.”
Anseth is not tackling the complex problem on her own: her team is collaborating with molecular biologists who specialize in diseases of the heart. “We're learning about cells in heart valves and what goes wrong that leads to these valve defects,” she says. “Once we understand what cues may be used to reverse this process, we can try to regenerate and grow healthy valve structures.”
Photo: Brigid McAuliffe