Microenvironmental Changes in the Surviving Fat 1 Year After Autologous Fat Transplantation for Breast Augmentation

Autologous fat is currently one of the most commonly used soft tissue materials in plastic surgery, but the changes that occur in fat after transplantation are unclear. Existing studies on the changes in surviving fat mostly involve animal experiments.

The aim of this study was to obtain surviving fat 1 year after clinical autologous fat transplantation for breast augmentation, to explain the microenvironmental changes after fat transplantation from a clinical perspective, and to verify previous research conclusions, thus providing new insight into fat survival.

Samples of surviving fat were obtained from 5 patients 1 year after they had undergone autologous fat transplantation for breast augmentation, and normal fat samples were obtained from 5 patients who had not undergone this procedure. The differences between CD68 and CD31 were analyzed immunohistochemically, and between CD34 and Ki67 by immunofluorescence. We also tested whether UCP-1 is expressed in surviving fat.

The relative CD68, CD34, and Ki67 expression levels in the surviving fat tissue were significantly higher than those in the normal fat tissue (PCD68 = 0.04, PCD34 = 0.03, PKi67 = 0.02). The relative CD31 expression was not significantly different between the two groups (P = 0.52). No UCP-1 expression was observed in any surviving fat tissue.

Chronic inflammatory reactions mediated by macrophages were detectable 1 year after autologous fat transplantation for breast augmentation. The mesenchymal stem cell content in surviving fat was higher than that in normal fat, but the number of blood vessels was close to that in normal breast fat tissue. No genesis of brown fat was found.