Macroencapsulation of human cartilage implants: pilot study with polyelectrolyte complex membrane encapsulation

Autogenous cartilage transplantation is a generally accepted method in reconstructive surgery. A promising alternative to this established method could be represented by in vitro engineering of cartilage tissue. In both methods of autogenous transplantation, host response induces reduction of transplant size and transplant instability to an unforseeable extent. To investigate if polyelectrolyte complex (PEC) membranes were able to avoid host-induced effects on implanted tissues without neglecting the tissue metabolism, human septal cartilage was encapsulated with polyelectrolyte complex membranes and subcutaneously implanted on the back of nude mice. Septal cartilage implants, without encapsulation served as control group. Histochemical and electron microscopic investigations were performed 1, 4, 8 and 16 weeks after implantation. In the case of an intact PEC-membrane no interactions between the host and the implant could be observed. In some implants, the capsule was torn in several areas and signs of chronic inflammation with the cartilage having been affected mildly could be observed. Implanted cartilage protected with PEC-encapsulation showed no signs of degeneration and significantly lower level of after effects of chronic inflammation than implanted cartilage without PEC-encapsulation. Therefore, it could be expected, that PEC membrane encapsulation offers a novel approach to protect cartilage implants from host response after autogenous transplantation.