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heart was barely functioning. Worse, two of hiscoronary arteries were fully blocked and anotherwas disastrously close. The experimentaltherapy was a no-go. The doctors said insteadthey had to perform a much riskier open heartsurgery—immediately.That’s when they discovered that his hearthad swelled to the size of a football. Fraizer’sprevious heart attacks had, through the years,caused part of his heart muscle to balloon out.Often, the part of the heart that is starved ofoxygen during an attack can become so damagedthat it cannot do the work it used to do.The rest of the heart tries to make up for it,yet it can’t always compensate. So the damagedpart of the heart responds by thinning,ballooning, and stiffening. These reactionsreduce the muscle’s efficiency further and canlead to heart failure—something that Fraizerhad been flirting with for years without evenknowing it.While Fraizer was having his heart resculptedin the operating room, William Wagner andcolleagues were several blocks away exploringhow to prevent the need for such operationsin the first place. Wagner, the deputy directorof the University of Pittsburgh–UPMCMcGowan Institute for Regenerative Medicine,is a tissue engineer and Pitt professor ofsurgery, bioengineering, and chemical engineering.Along with Pitt colleague MichaelSacks, William Kepler Whiteford Professorof Bioengineering, Wagner oversees the developmentof a biodegradable heart patch thatmay one day prevent the long-term cardiacdamage that Fraizer and others suffer afterheart attacks. Wagner and Sacks’ work was recognizedby Scientific American as among the 50most outstanding acts of leadership in scienceand technology in 2006.Reportedly, heart tissue has been extremelydifficult to engineer because of its mechanicalproperties. It is strong, yet flexible, and is moreeasily stretched in one direction than another,depending on the direction in which its fibersare aligned. In addition, the body is sensitive tothe introduction of foreign materials that don’tquite match heart tissue’s natural properties.In his office, Wagner is surrounded by oldjournal issues, images of blood vessels, a whiteboardon which someone has scribbled circuitdiagrams and graphs, three cacti (remnants ofa youth spent in Phoenix), and numerous photosof his two young boys. Someone wanderingin might wonder whether he is a scientist oran engineer, a surgeon or a chemist. Wagnerthinks of himself as a translator between theworlds of engineering and medicine. Throughthe years that has meant working closely withpatients, doctors, and other types of scientists.“The way I describe it is as engineeringapplied to address cardiovascular disease,”Wagner says of his work.Engineering cardiac tissue in the labrequires expertise in many areas—mechanicaland materials engineering, chemistry, molecularbiology, immunology, and surgery, to namea few. Pitt stands out, observers say, becauseit has established a cadre of experts who workcohesively together.“That’s really how high-impact science isbeing done nowadays,” Wagner says. “It’sbeing able to assemble teams of experts whereyou have world leaders in different areas comingtogether and hashing out ideas.”“They have really made things happen,”says Kim Woodhouse about Pitt’s cardiacbioengineers. Woodhouse is a professor ofengineering and applied chemistry at theUniversity of Toronto. The Pitt team is pragmatic,synergistic, and creative, she says, andthis combination puts them right “at the leadingedge.”Wagner first became interested in applyingengineering to medicine when he was in graduateschool for chemical engineering at theUniversity of Texas at Austin. One day, whenlistening to an engineering professor talk abouthis work on blood clots, Wagner suddenly sawhow the engineering science that he’d learnedas an undergraduate could be applied to thehuman body.“I immediately knew that’s what I wantedto do,” he says.He graduated with a PhD in chemical engineering,after having spent many a Saturdayat the Texas Medical Association Library,slouched over medical journal articles. ThenWagner got an unexpected call from a surgeonat the University of Pittsburgh looking to hirea postdoctoral fellow to study blood clots andartificial hearts.“And I’m thinking, Pittsburgh? I’m fromArizona,” says Wagner with a laugh. Nevertheless,he visited.“Within a couple of meetings with people,I realized that it was kind of like Mecca,” herecalls. The problems he had only seen onmicroscope stages or in library cubicles inTexas were right in front of him at Pitt, havinga “very real impact on patients every day,” hesays. He accepted the position.At that point, Wagner wasn’t quite readyto step up to the role of translator—he was,literally, still learning the language of medicine.“I knew a lot of the terms, and I’d read themdozens of times,” he says, “but I’d never actuallyheard them pronounced!” As he immersedhimself, he started noticing an interesting trend:Some medical terms were oddly vague, and thereason for this, he realized, was that no onereally understood the processes they were tryingto describe. That, he thought, was a hole thatengineering could help fill.Wagner, along with Michael Sacks, a PhDbiomechanical engineer with a dry sense ofhumor and an astute eye for detail, began closelystudying the mechanics of cardiac processes, anarea Sacks first started researching in graduateschool at the University of Texas SouthwesternMedical Center at Dallas. The heart can bethought of as a machine, and Wagner and Sackswanted to understand it inside and out so thatthey could, in a sense, reverse-engineer parts ofit. Wagner and Sacks realized there was a hugemedical need for engineered cardiac tissue.Other bioengineers have typically used materialsthat poorly mimic the properties of cardiactissue—so Wagner decided it was up to his teamto develop something better.The engineers imagined developing a cardiacpatch that could help damaged hearts repairthemselves. This patch would work best, theytheorized, if it could mimic the types of temporaryscaffolds the body makes on its own allthe time.“When you cut yourself, you make a clot,and then you put a temporary scaffold in there,”Wagner explains. Then special immune cellsarrive, release enzymes that help the tissue regenerate,and clear the temporary scaffold away.But when the heart gets injured during a heartattack or because of other defects, it might notbe able to repair itself. Instead, it might respondthe way Fraizer’s heart did—by ballooning out,which causes further problems and makes theheart even less efficient. Wagner and his teamthen wondered whether it would be possible tocreate a synthetic scaffold that, if applied to theheart within a few weeks of a heart attack, couldallow the heart to repair itself.They went to work. One of Wagner’s postdoctoralfellows, Jianjun Guan, created a polyurethanematerial that was nontoxic, highlyelastic, strong, and biodegradable. Polyurethaneis the stuff of seat cushions, and Wagnerexplains that, like a good cushion, the materialis strong yet flexible, able to bounce backafter being compressed or stretched. His teamfound ways to manipulate the material so thatit stretches more in one direction than the30 PITTMED