Breast implant capsules are partially composed of bone marrow-derived cells.

Capsular contracture is the most common complication following breast augmentation or reconstruction with implants. We recently demonstrated that bone marrow-derived cells provide fibroblasts to murine skin during wound healing. To determine if bone marrow-derived cells were the cellular source of periprosthetic capsules, we created chimeric C57BL mice containing bone marrow cells from isogeneic enhanced green fluorescent protein (EGFP(+)) mice and implanted with a textured silicone shell implant. We found that none of the mice developed infection or capsular contracture, but day 30 capsules were composed of 26.4 +/- 6.1% EGFP(+) cells, and day 60 capsules had 21.8 +/- 10.3% EGFP(+) cells. Immunohistochemistry revealed a small population of EGFP(+) cells in the capsules that were myofibroblasts. Thus, breast implant capsules are partially composed of bone marrow-derived cells and, given the potential of these cells to become myofibroblasts, may explain the cellular source of capsular contracture when it develops.