Future potentials for using osteogenic stem cells and biomaterials in orthopedics

Ideal skeletal reconstruction depends on regeneration of normal tissues tha t result from initiation of progenitor cell activity. However, knowledge of the origins and phenotypic characteristics of these progenitors and the co ntrolling factors that govern bone formation and remodeling to give a funct ional skeleton adequate for physiological needs is limited, Practical metho ds are currently being investigated to amplify in in vitro culture the appr opriate autologous cells to aid skeletal healing and reconstruction. Recent advances in the fields of biomaterials, biomimetics, and tissue engineerin g have focused attention on the potentials for clinical application, Curren t cell therapy procedures include the use of tissue-cultured skin cells for treatment of burns and ulcers, and in orthopedics, the use of cultured car tilage cells for articular defects. As mimicry of natural tissues is the go al, a fuller understanding of the development, structures, and functions of normal tissues is necessary. Practically all tissues are capable of being repaired by tissue engineering principles. Basic requirements include a sca ffold conducive to cell attachment and maintenance of cell function, togeth er with a rich source of progenitor cells. In the latter respect, bone is a special case and there is a vast potential for regeneration from cells wit h stem cell characteristics. The development of osteoblasts, chondroblasts, adipoblasts, myoblasts, and fibroblasts results from colonies derived from such single cells. They may thus, theoretically, be useful for regeneratio n of all tissues that this variety of cells comprise: bone, cartilage, fat, muscle, tendons, and ligaments. Also relevant to tissue reconstruction is the field of genetic engineering, which as a principal step in gene therapy would be the introduction of a functional specific human DNA into cells of a patient with a genetic disease that affects mainly a particular tissue o r organ, Such a situation is pertinent to osteogenesis imperfecta, for exam ple, where in more severely affected individuals any improvements in long b one quality would be beneficial to the patient. In conclusion, the potentia ls for using osteogenic stem cells and biomaterials in orthopedics for skel etal healing is immense, and work in this area is likely to expand signific antly in the future, (Bone 25:5S-9S; 1999) (C) 1999 by Elsevier Science Inc . All rights reserved.