In a study of 14 people who had a heart attack, fat-derived stem cells reduced the amount of damaged heart tissue, increased blood flow in the heart, and improved the heart's pumping ability, compared with placebo.
Due to the study's small size, however, the difference between the two groups could have been due to chance.
"But given the dramatic and consistent results, we think it is a real effect," says study head Eric Duckers, MD, PhD, of Erasmus University Medical Center in Rotterdam, Netherlands.
U.S. stem cell researcher Douglas Losordo, MD, of the program in cardiovascular regenerative medicine at Northwestern Memorial Hospital in Chicago, tells WebMD, "The evidence strongly suggests fat stem cells can stimulate the repair process after a heart attack. But these are still early days. We have to await the results of larger randomized trials [pitting placebo against fat stem cells] to determine if the method improves quality of life and extends lives."
It's not the first time heart attack patients have been treated with stem cells. But previous studies used bone marrow stem cells, Duckers says. "The advantage of fat-derived cells is the ease with which you can get them."
"You don't get enough stem cells from bone marrow, so you have to culture them in the lab, a process that can take six to eight weeks," Duckers tells WebMD. He estimates that the 40 cubic centimeters of bone marrow typically removed yields about 25,000 stem cells.
In contrast, just 100 cubic centimeters of fat tissue -- about a half a coffee cup -- contains 2 million stem cells, he says. "With that many cells, you can isolate them and go straightway back to the patient."
How the Stem Cell Technique Works
In the study, the first of its kind, people were treated within 24 hours of their heart attack after undergoing cardiac catheterization to assess blood flow and angioplasty to open up the blocked heart artery and restore blood flow.
The findings were presented here at the American Heart Association's Scientific Sessions 2010.
The researchers liposuctioned fat from the abdomen of 10 patients, isolated 20 million stem cells, and infused them back into the patient through a catheter -- all in 10 minutes. The other four patients got placebo infusions.
By six months later, SPECT imaging showed that blood flow to the heart had improved 3.5-fold in people getting fat stem cells, compared with those getting placebo. Heart pumping ability increased 5.7% in the stem cell group.
As seen on MRI scans, the average area of heart muscle scarring was cut in half in the treatment group, from 31.6% after the heart attack to 15.4%.
"It was dramatic," Duckers says. "There was one patient in whom we couldn't even see a scar anymore."
Among people getting placebo infusions, there was no change in scarring.
The infused stem cells did not interfere with blood flow in the heart or cause potentially fatal erratic heartbeats called ventricular arrhythmias, both of which had been a concern.
Duckers notes that all the patients were white Europeans. The results are not necessarily applicable to non-whites, he says.
The researchers have initiated a more robust phase II-III clinical trial called ADVANCE that will enroll up to 375 heart attack patients at 35 medical centers in the European Union. Patients will get one of two doses of fat-derived stem cells or placebo infusions.
The study was funded by Cytori Therapeutics Inc.
This study was presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.