For example, chondrocytes dissociation from healthy tissue and their ex vivo expansion (to reach the proper number for reimplantation) would fall under the somatic cell therapy product definition. It was immediately obvious that different rules should apply to tissue engineered products. Orthopedic surgeons had previously used autologous tissues (for ex. Growth factors to ultimately organize into normal healthy bone or cartilage as the scaffold Ideally the cells would attach to the scaffoldĪnd proliferate and differentiate under the control of endogenous and exogenous Molecules and three-dimensional matrices. Involves one or more of the following key ingredients: harvested cells, recombinant signaling Permanent implants, the tissue-engineered bone becomes integrated within the patient,Īffording a potentially permanent and specific cure of the disease state. The function of the two types of tissues. Seeking to address the needs by the realization of viable substitutes that restore and maintain Particularly, in the repair of bone and cartilage, the tissue engineering approaches are Moreover the manipulation required was much more than that needed for autologous bone marrow transplant, where the source tissue is harvested but hardly “processed” at all. When commercial establishments began to provide these manipulated cells to surgeons within the United States it became clear that such a class of products had not been explicitly considered by the FDA. Each of these applications may also take advantage of a possible genetic modification of the patient's or of the donor's cells by the insertion of a modified, or repaired or new gene.Ĭommercial distribution of such products could provide a relatively simple solution to a common type of injuries, satisfying the needs of a large number of patients. Other applications of the tissue engineering approaches presently at a preclinical or very early clinical stage are the repair of skeletal and cardiac muscle fibers, the implant of fat cells for cosmetic augmentation, the realization of vascular prosthesis and the selection of cells with a neuroregenerative potential. Additional examples were chondrocytes cultured and implanted in focal cartilage defects, allogeneic dermal fibroblasts for dermal wound healing and the transplant of specific endocrine cells. The first “manipulated” cells intended for structural repair or reconstruction were autologous keratinocytes expanded ex vivo for treatment of burn wounds and leg ulcers. Repair of soft tissues - previously hardly feasible - may now be envisioned and performed by transplanting the engineered tissue obtained from the expansion of cells of the patient in association with resorbable materials (either synthetic or of natural origin). Ideally the new approaches based on cell-biomaterial associated products will substitute the previously used devices which do not represent sufficient or satisfactory solutions. These can now be used in unlimited quantities.
Tissue engineering, i.e., the association of ex vivo grown cells and/or biologically active molecules with different materials, is furthermore driving the production, the testing and the marketing of new generations of transplantable biomaterials. In particular, a role for several growth factors controlling cell proliferation and differentiation has been established and cell culture techniques have been improved to allow the in vitro selective expansion of restricted cell populations.
Have made available to clinicians tissues to be used in reconstructive surgery for the repair of extensive lesions. Progress in cell biology and biotechnology and improvements in therapeutic treatments Represent useful examples to evidence the related regulatory issues. The nature of the products or of the therapeutic strategies will not be dealt with, unless they A general outlook of the requisites for the manufacturing of tissue-engineered products will be discussed, spanning from the origin of the cellular component of the composite to the release The reader's attention will be primarily focused on the cell-based composites, being these products the most challenging in terms of application of this approach to bone repair. To be considered when projecting a possible product application in the field of tissue engineering. We will discuss existing guidelines and legislation, giving an overview of the requirements The influence of the market and of the private enterprises, as well as that of the academic world, is also taken into consideration when defining rules to follow. An overview of the current regulatory authorities is presented to evidence their role as responsible rule-makers. Researchers must consider when planning new therapeutic approaches, especially in the bone and cartilage repair field. In this chapter we propose a brief description of the relevant issues that tissue-engineering