Growth factor concentrates are defined as a class of secreted bioactive molecules that affect cells.growth, but this definition has now been broadened to include secreted factors that promote or inhibitmitosis or affect cell differentiation. They act on the surface receptors of characteristic cells, transmittingtheir growth signals to other intracellular components, resulting in changes in gene expression.Many growth factors are peptides or proteins; they bind with high affinity to a specific surface receptor.Most cell surface receptors for growth factors show tyrosine kinase activity, meaning they put aphosphate group on a downstream protein tyrosine residue. An exception are the surface receptors forthe transforming growth factor-beta (TGF-beta) family of cytokines. When activated by the binding ofTGF-Beta cytokines, the receptor phosphorylates downstream proteins on serine and threonine.residues.
Some growth factors are small peptides called cytokines. Although all cytokines affect signalstransduction pathways, only those cytokines that affect cell growth and differentiation signalling pathwaysare considered growth factors. Examples of protein growth factors are epidermal growth factor (EGF),vascular endothelial growth factor (VEGF), and platelet-derived growth factor (PDGF). Insulin growthfactor (IGF), and TGF (transforming growth factor). Growth factors achieve specificity for specific cell types.through the expression of highly specific cell surface receptors, which helps in cell proliferation andrestructures the follicular unit grafts. The growth factor concentrate ACD gel-based tubes are preactivated and delivers substantial results within 3U+002d4 sessions in saving the ailing grafts and inspiring hairre-growth.
