Tecnica Co.Di per la produzione di cartilagine solida umana

Abstract

Abstract English Tissue or organ transplantation is severely limited by the problems of donor shortage and immune rejection from the patients. The cartilage defects are difficult to reconstruct. In head and neck surgery, as in septal reconstruction, auricular reconstruction for injury or malformation, in laryngotracheal reconstruction, surgeons harvest autologous cartilage from a donor site (of the patient) in order to reconstruct the defect. Today's current therapies to reconstruct cartilage defects involve the use of autologous cartilage grafts or biocompatible implants, but these seem inadequate to restore form and function, have many limits and are related with many complications. Due to the its limited ability to self repair, cartilage is an ideal candidate for tissue engineering. The essential requirement for a bio-engineered cartilage are: cell source and 3D biocompatible scaffold that allow cell replication and chondrogenesis. The main problem in tissue engineered cartilage is the scaffold. Several scaffold material shave been investigated for tissue engineering cartilage. It is necessary a 3 D scaffold that could define the shape of the engineering tissue, had to support the cell proliferation, maintaining their differentiation. The three-dimensional scaffold used by the authors is a dermal substitute usually employed to cover the loss of cutaneous substance and for the treatment of difficult wounds. This scaffold is a 3-dimensional porous matrix of cross-linked collagen and glycosaminoglycans. The authors used human chondrocytes Kit: hyaline human chondrocytes, in specific chondrocytes grow medium for cells ready to be used, are easy to be bought. The authors have produced three-dimensional hyaline cartilage using human chondrocytes on a three-dimensional scaffold, a cube , and implanting the chondrocyte-scaffold complex, without adding growth factors or other, in a subcutaneous pocket created on the back of a rabbit. After 8 weeks the neocartilage was explanted and hystological analysis by light microscopy and HLA typization were made. Histological section shows the following: proliferation of immature cartilage associated with abundant neoangiogenesis, with a central portion of mature cartilage, in the form of plate. Is evident also an eosinophilic infiltrate (immuno-allergic phase) to the periphery of the specimen. The inflammatory infiltrate, evident in the sample, was identified and consists mainly of eosinophils and T lymphocytes (CD3 positive). No evidence of inflammatory reaction to foreign body. Proliferating chondrocytes present cytoplasms and nuclei without necrobiotic alterations, cytolytic (as coagulation and / or colliquative necrosis) and apoptotic. These are signs of cell viability. HLA tissue typing showed the human origin of proliferating chondrocytes The exams confirm that the tissue engineering product is a well organized cartilage, that maintains the cube shape of the scaffold. In all the samples neocartilage was produced and was similar histologically to native cartilage. The advantages of this engineered tissue are multiple: the new cartilage retains the original 3-D shape of the scaffold so that it could be created into the desired shape preoperatively, using an easy-to-find scaffold. In addition, the engineered cartilage is an autologous tissue that would avoid the risk of graft rejection or extrusion while encouraging long-term durability and even proportional growth.