Evaluating the Safety and Efficacy of Cartilage Regeneration with Tunable Inflammation Resistance

Abstract The repair of large cartilage lesionswhich often lead to osteoarthritisOAremains a significant clinical problem with few good treatment optionsPrevious work at Cytex has focused on the developing of aD woven textile scaffold for cartilage repairdesigned to function immediately upon implantationwhile encouraging cell ingrowthproliferationand subsequent tissue developmentBy combining this proprietaryD woven implant with adiposederived stem cellsASCswe have demonstrated the ability to generate largeanatomically shaped cartilage constructs with biomimetic mechanical propertiesNeverthelessfor a cell based cartilage therapy to be successful in an OA patientit must withstand the catabolic effects of joint inflammationwhich are mediated by the action of elevated levels of pro inflammatory cytokines such as interleukinILand tumor necrosis factor alphaTNFaHoweverbecause of the pleiotropic role of ILand TNFa in vivolong term sustained anticytokine therapy is not recommendedThereforethe objective of this project is to evaluate the safety and efficacy of an engineered functional cartilage replacement capable of protecting itself from OA inflammation by producing an anti cytokine therapyTo this endwe propose to use an inflammation responsive promoter to drive expression of therapeutic factorsspecificallyILreceptor antagonist and soluble TNF receptorThis will create an auto regulated system in which cells express and secrete anti cytokine proteins only when inflammatory signaling is presentIn Aimwe will modulate the lentiviral transduction process in an effort to minimize the risk of genetic side effects in our biomimetic cartilage implantOur goal is to minimize the number of viral integration events in each cellwhile maintaining a high transduction efficiencyso that the ASCs in our implant can effectively deliver the anti cytokine therapyIn Aimour engineered cartilage will be implanted subcutaneously in an inflammatory mouse model to test the construct s ability to sense and prevent catabolic degradationSerum will be collected from the mice longitudinally to measure the levels of inflammatory cytokines present in the modelas well as the levels of anti cytokine therapeutics produced by our implant in direct response to the inflammatory cytokinesAt sacrificethe cartilage constructs will be excised and assessed histologicallybiochemicallyand biomechanically to quantify any degradative changes that have occurred in the tissueAdditionallyall major organ systems of the mice will be examined histologically to assess the safety of implanting transduced cells and utilizing anti cytokine therapyThis proposal addresses the clinical need for large functional cartilage replacements that can thrive in an inflamed osteoarthritic jointand couldas a consequencehave a major impact on the treatment paradigm of this disease OsteoarthritisOAis one of the leading causes of disability in the worldand while a totaljoint replacement is a highly successful treatment option for patients older thanyearsof agethere areunfortunatelyno good current treatment options for the young patientpopulation suffering from this diseaseThe objective of this study is to further the developmentof abiosyntheticimplant that can both replace diseased cartilage and also detect and respond todegradative inflammation to protect the long term integrity of the implant