Extracellular Matrix Modifications in Rat Tissues of Different Ages: Correlations between elastin and collagen type I mRNA expression and Iysyl-oxidase activity

We used a rat model to correlate age, matrix gene expression and lysyl oxidase activity in three connective tissues, skin, aorta and lung. By in situ hybridization, we showed that intense collagen type I and elastin mRNA expression were limited to a brief postnatal period. Although there were some organ-specific differences, the mRNA abundance for these two scleroproteins drastically diminished with time. Thus, the majority of mesenchymal cells in young (60 days) and old (720 days) animals, appeared to be in a quiescent state, consistent with the slow turnover of these two scleroproteins. We also measured the activity of lysyl oxidase, an enzyme which plays a crucial role in the formation of crosslinks in both procollagen and tropoelastin molecules. In all the organs investigated, we observed a tissue-dependent pattern of activity. Moreover in this study we focused on the importance of gene matrix expression in evaluating lysyl oxidase activity of aging tissues

Localized effects of transforming growth factor beta on extracellular matrix gene expression during wound healing. Excisional wound model.

The effect of transforming growth factor-beta 1 (TGF-beta 1) on matrix gene expression has been investigated during the process of wound repair, where the formation of new connective tissue represents a critical step in restoring tissue integrity. Split-thickness excisional wounds in the pig were studied by in situ hybridization in order to obtain subjective findings on the activity and location of cells involved in matrix gene expression after the administration of recombinant TGF-beta 1. Data focus on the stimulatory role of this growth factor in granulation tissue formation, on the enhanced mRNA content of collagen types I and III, fibronectin, TGF-beta 1 itself, and on the reduction in stromelysin mRNA, suggesting that increased matrix formation measured after treatment with TGF-beta 1 is due to fibroplasia regulated by the abundance of mRNAs for several different structural, matrix proteins as well as inhibition of proteolytic phenomena elicited by metalloproteinases. These studies reveal elastin mRNA early in the repair process, and elastin mRNA expression is enhanced by administration of TGF-beta 1. Moreover, we show that TGF-beta 1 was auto-stimulating in wounds, accounting, at least in part, for the persistent effects of single doses of this multipotential cytokine

Proteomic Approaches for Studying the Phases of Wound Healing

© 2009, Springer Berlin Heidelberg. Proteome level information is necessary to understand the function of specific cell types and their roles in health and disease. Proteomics is a rapidly developing field with a wide range of applications in wound healing. The ability to use proteomics to assess the wound healing process would have many benefits, including earlier evidence of healing and better understanding of how different treatments affect the wound at the protein level. The basis of what is known about the chronic wound proteome is based on results from a broad collection of studies utilizing a number of different proteomic techniques on fluids and tissues from wounds with different etiologies. The identification of biomarkers associated with healing or delayed healing in chronic wounds could have great significance in the use of current treatments, as well as in the development of new therapeutic interventions