The tissue engineering industry is a rapidly developing frontier in the medical device and pharmaceutical world. One major development in the tissue engineering industry is the application of growth factors in generating new tissue. Simple molecules isolated from the Tumor Growth Factor (TGF) superfamily of proteins have the power to affect cells and the growth of tissues with dramatic effects offering the potential to direct the establishment of entire organs if applied properly.
Several therapies involving variants of growth factors have already been approved and are marketed with revenues exceeding hundreds of millions of dollars. Regranex gel, now marketed by Healthpoint, Inc. delivers a molecule called Platelet Derived Growth Factor (PDGF) directly to wounds in diabetic patients. PDGF is present naturally in platelets is now produced recombinantly through modern genetic engineering and when applied to a wound causes fibroblast cells within the wound tissue to have increased mobility and produce new tissue at an accelerated rate leading to faster wound healing. Stryker corporation markets OP-1 which contains the growth factor Bone Morphogenic Protein (BMP) 6.
BMP6 causes basal adult stem cells to convert to osteogenic cells including osteoclastss and osteoblasts and produce new bone tissue. The product has applications in restoring new bone tissue in shattered long bones where no union exists between the two ends of broken bone. A similar BMP molecule is used to fuse vertebra in the spine over damaged spinal discs to relieve pressure on the spine nerve. The BMP produces new bone fusing the two vertebra over a matter of days effectively guiding and producing new tissue in the exact location where the drug is applied.
Genentech-Roche markets an antagonist to a growth factor that is used to prevent macular degeneration in opthalmology patients and to decrease the growth of tumors in oncology. The drug, called Avastin is an antigen in that it inhibits the binding of a growth factor called vascular endothelial growth factor (VEGF) to vascular progenitor cells. Both macular degeneration and the blood supply of tumors depend on growth of new blood vessels and the inhibition of this factor has led to significant advances in treatment of both of these diseases.
The tissue engineering industry is poised for substantial growth as new therapies undergo testing in disease and organ regeneration. VEGF is undergoing testing in vascular regeneration for cardiac and venous reflux diseases where the directed application of the molecule can rebuild missing blood vessels in patients where that growth is compromised. Keratinocyte cells which regenerate the top layer of skin respond rapidly to keratinocyte growth factor which shows promise as a therapy to regrow skin in burn patients.
Combination therapies in which sequential growth factors are released show potential to regrow organs and specific components are regenerated in a stepwise fashion to form vascular structure, connective tissue and new cellular function. As the growth factor component of the tissue engineering industry matures it is feasible that carefully metered doses of growth factors can be used to effectively regrow new organs in patients where organ function has become impaired.