Tissue-engineered nipple reconstruction

We describe a simple, effective approach to the creation of autologous tiss ue-engineered cartilage in the shape of a human nipple by injecting a rever se thermosensitive polymer seeded with autologous chondrocytes in an immuno competent porcine animal model. A biodegradable, biocompatible copolymer of polyethylene oxide and polypropylene oxide (Pluronic F-127),which exists a s a liquid below 4 degrees C and polymerizes to a thick gel when it is expo sed to physiologic temperatures (body temperatures), was used as a vehicle for chondrocyte delivery and as a scaffold to guide growth. Autologous chondrocytes isolated from porcine auricular elastic cartilage a nd suspended in 30% (weight/volume) Pluronic F-127 were injected on the ven tral surface of the pigs from which the cells had been isolated. A circumfe rential subdermal suture was used to support the contour of the implant and assist in its projection in the form of a human nipple. After 3 weeks, the skin over and surrounding the implant was tattooed to create the appearanc e of a human nipple-areolar complex. As controls, an equal number of inject ions were made using either cells alone (not suspended in hydrogel), or hyd rogel alone. After 10 weeks, all specimens were excised and examined both g rossly and histologically. Before harvesting, visual inspection of the tattooed chondrocyte-Pluronic F -127 hydrogel implant sites revealed that they closely resembled a human fe male nipple-areolar complex. Nodules were similar in size, shape, and textu re to a human nipple at each injection site. Glistening opalescent tissue w as surgically isolated from each implant site. Hematoxylin and eosin, safra nine o, trichrome blue, and Verhoeff's stains of the experimental implants showed nodules with the characteristic histologic signs of elastic cartilag e. Control injections of copolymer hydrogel alone exhibited no evidence of cartilage formation. Control injections of chondrocytes alone showed eviden ce of dissociated microscopic nodules of elastic cartilage.