Submitted to: American Journal of Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 23, 2003
Publication Date: October 1, 2003
Citation: Elsasser, T.H. 2003. Insulin-like growth factor-I: A traffic control device on the road to tissue recovery. American Journal of Physiology. 285:R722-R723.
Interpretive Summary: For years following its identification as the peptide that modulates the anabolic activities of growth hormone, insulin-like growth factor-1 (IGF-1) has largely been thought of in a nutrition and growth regulator. We now see that the role of IGF-1 in the body is significantly more sophisticated than originally thought, in particular as regards its interaction with the immune system through a systematized influence of several signal transduction pathways that accelerate or retard tissue growth as the scenario dictates. The feature discussed herein is that through the use of a technique called gene transfer, a specific delivery of the IGF-1 gene can be delivered to a tissue region and only that region will be affected by the subsequent manufacture and production of IGF-1 protein. To accomplish this, the active part of the IGF-1 gene is biochemically placed inside another set of genes that will allow the IGF-1 gene to be activated inside the body. The gene set is mixed into a fatty matrix and injected by needle into a specific site. In this manner, the actions of IGF-1 are present only locally and do not interfere with other body functions. Therefore wound healing can be hastened locally improving the health of the patient.
This review article serves to create a logic path originating with generalizations regarding insulin-like growth factor-1 (IGF-1) as a system wide growth factor affecting protein and energy use on a whole body basis and ending with specific novel roles for IGF-1 as a multifunctional regulator of apoptosis and tissue repair. The review serves as an invited 'Editorial Focus' for the American Journal of Physiology highlighting a series of papers written by Jeschke et al., that describe the utility of site-directed, liposome-mediated IGF-1 gene transfer as a therapeutic advance to speed tissue healing and wound repair in animals. In the process of reviewing relevant literature, this paper demonstrates how the biochemical attributes of IGF-1 can be temporally up- and down-regulated in controlling the proinflammatory mediator nuclear factor kappa-B (NF-'B).