Bone And Cartilage Tissue Engineering For Growth Modification Using Bone Marrow Derived Mesenchymal Stem Cells (Bmmscs) On A Resorbable Electro-Spun Scaffold

Abstract

Introduction: Cartilage tissue engineering (CTE), using bone marrow stem cells, has been extensively used in orthopedic surgery mainly in the healing of osteoarthritis. The long term implication for successful CTE would be its application in animals then humans to stimulate mandibular growth as would be needed in the orthopedic treatment of severe distoclusions. Aims: Evaluate: 1. Osteogenic and chondrogenic potential of bone marrow mesenchymal stem cells (BMMSCs) embedded in an electrospun scaffold [poly L/DL lactide (PLDL)] with and without tension. 2. The effect of tension on stem cells differentiation. 3. Bone and cartilage communication with and without tension. Methods: BMMSCs are isolated from green fluorescent protein (GFP) transgenic mice using intact bone marrow plugs, and bone stroma by enzymatic digestion. BMMSCs and Human MSCs are then seeded on PLDL resorbable electrospun scaffold to replace 3D pieces of in vivo tissues. Dexamethasone and TGF ß are added every 3 days, over 21 days, to induce osteogenic and chondrogenic differentiation respectively. Successful cell seeding on the PLDL mesh is examined microscopically. Bone and cartilage differentiation is identified through alizarin red and alcian blue staining, respectively and through immunofluorescence by identifying osteopontin and Aggrecan antibodies. A uniaxial stretching device (STB-140; Strex) applies continuous tension on the MSCs. Stem cells differentiation is detected by morphological and orientation changes microscopically and at the gene expression level. Collagen type I, alkaline phosphatase, collagen type II and aggrecan expression are detected by real time PCR. Results: Murine bone marrow MSCs were successfully isolated from bone marrow plugs and bone. Human MSCs seeded on PLDL scaffold were effectively differentiated into bone and cartilage. Stretching increased aggrecan expression of stem cells. There is an indirect communication between bone and stem cells as well as cartilage and stem cells. Conclusion: Therefore, functional appliances in addition to stem cell therapy are an alternative to increase condylar growth. Furthermore, in vivo studies are necessary to evaluate the effect and safety of this therapy before any clinical trial.