Human Embryonic Stem Cell-Derived Endothelial Precursor Cell Conditioned Medium Reduces the Thickness of the Capsule Around Silicone Implants in Rats.

[BACKGROUND] We postulated that the fibrotic capsule around a silicone implant could be induced by ischemic conditions, based on previous reports that hypoxia is an important microenvironmental factor in the development of tissue fibrosis.

[OBJECTIVE] This study aimed to determine the effect of human embryonic stem cell (hESC)-derived endothelial precursor cell (EPC) conditioned medium (CM), which has strong angiogenic potential, on the development of capsule around the silicone implant in a rat model.

[METHODS AND MATERIALS] Three groups had a mini-silicone implant with a smooth surface inserted. In 2 experimental groups, hESC-EPC CM was administered into the subcutaneous pocket either 1 or 2 times. After 2 months, the capsules were harvested and analyzed by histologic examination.

[RESULTS] There was a significant reduction in the thickness of the peri-implant capsules (P < 0.05) between the control and experimental groups. There is no tendency that hESC-EPC CM reduces inflammatory reaction in early postoperative periods. The experimental group showed increased angiogenesis compared to the control group (P < 0.05).

[CONCLUSIONS] Tissue hypoxia around the implant may be another cause for the peri-implant capsule. A preventive or therapeutic strategy to decrease capsular contracture by relieving the ischemic condition around the implant can be investigated in the future.