Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Sir,

We read with great interest the article entitled “Effects of Insulin, Metoprolol and Deferoxamine on Fat Graft Survival” by Okyay et al. [1] in Aesthetic Plastic Surgery. The authors found that the three drugs did not exert a significant influence on fat graft survival.

The fat grafts treated with three kinds of drugs and the control group were implanted into the back of the rat. We are concerned that implanting different drugs on the back of one rat would result in drug absorption by the body and interfere with other groups.

In this study, the inguinal fat pads were split into four nearly equal parts as grafts. However, there would be a larger contact area between the grafts and the drug if the grafts were dissected into small pieces. Both shredded fat grafts and fat mass transplantation have been reported in the literature [2, 3], whose outcome may be different.