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

Autogenous cartilage transplantation is a generally accepted method in reco nstructive surgery. A promising alternative to this established method coul d be represented by in vitro engineering of cartilage tissue. In both metho ds of autogenous transplantation, host response induces reduction of transp lant size and transplant instability to an unforseeable extent. To investig ate if polyelectrolyte complex (PEC) membranes were able to avoid host-indu ced effects on implanted tissues without neglecting the tissue metabolism, human septal cartilage was encapsulated with polyelectrolyte complex membra nes 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 af ter implantation. In the case of an intact PEC-membrane no interactions bet ween the host and the implant could be observed. In some implants, the caps ule was torn in several areas and signs of chronic inflammation with the ca rtilage having been affected mildly could be observed. Implanted cartilage protected with PEC-encapsulation showed no signs of degeneration and signif icantly 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 im plants from host response after autogenous transplantation. (C) 2000 Elsevi er Science Ltd. All rights reserved.