Tissue engineering has been applied to various tissues, and particularly significant progress has been made in the areas of skin, cartilage, and bone regeneration. Inclusion of bioactive factors into the synthetic scaffolds has been suggested as one of the possible tissue engineering strategies. The growth factors are polypeptides that transmit signals to modulate cellular activities. They have short half-lives, for example, platelet-derived growth factor (PDGF), isolated from platelets, has a half life of less than 2 minutes when injected intravenously. Extended biological activity and the controlled release of growth factor are achieved by incorporating growth factor into the polymeric device. This review will focus on growth factor delivery for tissue engineering. Particular examples will be given whereby growth factors are delivered from a tissue-engineered device to facilitate wound healing and tissue repair.
Animal ; Biomedical Engineering/methods* ; Bone Morphogenetic Proteins/administration & dosage ; Cytokines/therapeutic use ; Cytokines/administration & dosage* ; Growth Substances/physiology

Recently, thanks to the rapid progress of new technologies in cell modulation, extracellular matrix fabrication and synthetic polymers mimicking bodily structures, the self-regeneration of bodily defects by host tissue has been considered by many researchers. The conventional science of art in biomaterials has been concerned with restoring damaged tissue using non-biological materials such as metals, ceramics and synthetic polymers. To overcome the limitations of using such non-viable materials, several attempts to construct artificial organs mimicking natural tissue by combining modulated cells with extracellular matrix-hybridized synthetic polymers have produced many worthy results with biologically functioning artificial tissues. The process involved in manufacturing biomaterials mimicking living tissue is generally called tissue engineering. However recently, the extension of knowledge about cell biology and embryology has naturally moved the focus from tissue restoration to tissue regeneration. Especially, embryonic and mesenchymal stem cells are attractive resources due to their potential for the differentiation of various tissue cells in response to signal transduction mediated by cytokines. Although no one knows yet what is the exact factor responsible for a stem cell's ability to differentiate between specific cells to generate specific tissue, what has been agreed is that delivering stem cells into the body provides a strong potential for the regeneration of tissue. In this review, the historical issues and future possibilities involved in medical tissue restoration and tissue regeneration are discussed.
Animal ; Biocompatible Materials/therapeutic use ; Biodegradation ; Biomedical Engineering*y ; Cell Transplantation/methods ; Extracellular Matrix/physiology ; Growth Substances/therapeutic use ; Growth Substances/administration & dosage ; Human ; Polymers/therapeutic use ; Regeneration* ; Stem Cells/transplantation

OBJECTIVETo study the effect of autogenous vein cuff and injection of cerebral cell growth peptide on the recovery of the injured facial nerve.

METHODSThe injured facial nerve was anastomosed and covered with an autogenous vein cuff. Cerebral cell growth peptide was then injected to it. The different repairing methods were evaluated and compared with electromyography and observing functional recovery of the mimetic muscles.

RESULTSThe new repairing method accelerated the recovery of the injured facial nerve. The recovery period of mimetic muscle function was significant shorter than the traditional method (P < 0.01). The recovery period of I-stage repairing was significant shorter than that of II--stage repairing (P < 0.01). The conduction velocity of the repaired facial nerves had no obvious differences between the new repairing method and the traditional method (P > 0.05).

CONCLUSIONApplication of the autogenous vein cuff to cover the nerve anastomosis and injection of cerebral cell growth peptide is a promising method for facial nerve repairing.

Adolescent ; Adult ; Aged ; Child ; Facial Nerve ; physiopathology ; Facial Nerve Injuries ; physiopathology ; surgery ; Female ; Growth Substances ; administration & dosage ; Humans ; Male ; Middle Aged ; Neural Conduction ; Veins ; transplantation