German researchers looking at the reliability and regenerative potential of fat grafting report in a recent study that the abdomen might be a better site for fat harvesting than the inner thigh and knee.

In trying to identify the most appropriate fat harvesting site, the researchers studied lipoaspirate properties of fat from the three body areas. They harvested lipoaspirates from 25 healthy subjects and measured the content of soluble factors as well as assessed the yield, adipogenic differentiation, proliferation of stromal vascular fraction cells and the percentage of adipose-derived stem cells in the stromal vascular fraction, according to theAesthetic Surgery Journal study published earlier this year

They found that abdominal lipoaspirates had significantly higher matrix metalloproteinase-9 concentrations, compared with those in the knee. While it was not a statistically significant finding, the abdomen also tended to be the site with the highest contents of basic fibroblast growth factor, platelet-derived growth factor-BB and insulin-like growth factor.

So, while the potentially richer soluble factor content from abdominal fat might be a slight favorite over that from the inner thigh and knee, according to the authors, it’s not the only criteria to consider when deciding from where to harvest fat.

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Lisa M. Donofrio, M.D., who is not a study author but commented on its findings forCosmetic Surgery Times, says, “It’s possible that where the fat is harvested from matters, but we need much more information to make that decision.”

Dr. Donofrio, who is vice president of the American Society for Dermatologic Surgery and associate clinical professor of dermatology at Yale University School of Medicine and Tulane University School of Medicine, says additional helpful information should address body shape. Where did the participants tend to store their fat? Were they “apples” or “pears”?

“In my experience, this is the most important question when deciding where to harvest from. Not only does it benefit the patient cosmetically, but perhaps the inability to lose the fat from these areas at least anecdotally suggests a better, or more robust ‘take,’” Dr. Donofrio says. “Interestingly, I hardly ever take fat from the abdomen, inner thighs or knees. My preferred harvest sites are flanks (men and women) and outer thighs in women. I would have liked to see these areas investigated in this study.”

Dr. Santos’s opinion: “It’s important to harvest from the site that might provide the highest success for fat take.  The abdomen tends to have the highest concentration of the important growth factors and stem cells when compared to other harvest sites.  I favor harvesting from this site whenever possible.”