Cytori’s system is already used in Europe, Japan, and elsewhere for cosmetic enhancement, wound healing, and breast reconstruction surgery. But for cardiac use, the company had to retool its “Celution” machine to create a solution safe enough to be injected directly into the coronary artery without clotting. The procedure is relatively straightforward. When a patient comes to the emergency room after a heart attack, a physician removes a fat sample and runs it through Cytori’s machine, where enzymes break down the fat and free up the desired cells in the surrounding matrix. “We’ve taken a seven-to-eight-hour lab process, validated it, optimized it, and put it in a box. Then each patient gets his own sterile tissue right back,” Calhoun says. An hour after the fat is harvested, surgeons place a stent into the patient’s coronary artery and deliver the slurry of cells.
The procedure has been tested in a 12-person pilot trial in Europe, and the results seem encouraging: after six months, patients who were given a solution of their own fat-derived stem cells within 12 hours of a heart attack had about half as much dead tissue as those who hadn’t had the treatment. That translated into fewer irregular heartbeats, better oxygen delivery, and improved blood flow. (Another trial, for chronic heart failure, also shows potential, and the procedure has been approved in Europe.)
Cytori began a large-scale trial this month and hopes to test the procedure on 360 patients. The company aims to start large-scale clinical trials on heart attack patients in the United States by 2014 and on patients with chronic heart failure even earlier than that.
“This cell type holds a lot of potential, and I think it could become a very important treatment for heart attack and [restricted blood flow],” says Keith March, director of the Indiana Center for Vascular Biology and Medicine at Indiana University in Indianapolis. “So the fact that they’re starting this trial and have shown good evidence of feasibility and safety is very encouraging—we’re anxious to see what it shows. That these cells can be obtained so readily and the procedure done in a point-of-care fashion means that this technology could be affordable and accessible even in areas of the world where highly technical surgery may not be possible.”
But it’s still early. Clinical trials of stem cells derived from bone marrow have shown mixed results in treating heart disease, and it’s unclear whether fat-derived cells will fare better. “If it works, it would be wonderful to have a ready-made source of autologous stem cells,” says Richard Schatz, research director of cardiovascular interventions at Scripps Health in San Diego, one of the inventors of the coronary stent. But he and others note that it will take many more trials to determine how effective Cytori’s methods are compared with treatments based on marrow stem cells.