Co-cultured human mast cells stimulate fibroblast-mediated contraction of collagen gels

In the current study, we asked whether mast cells might modulate remodeling of extracellular matrix by affecting fibroblast-mediated contraction of th ree-dimensional collagen gels. Mast cells and human lung fibroblasts were c o-cultured in floating type I collagen gels. The area of the gels was measu red by an image analyzer. Mast cells in co-culture augmented fibroblast con tractility (P < 0.001) in a time- and concentration dependent manner. The t ryptase inhibitor bis(5-amidino-2-benzimidazo-1-yl)methane (BABIM) were una ble to block the augmented fibroblast contractility induced by co-cultured mast cells and tryptase added alone in the culture system had no effect on contractility, suggesting that other mediators besides tryptase might be in volved. The amount of collagen in dissolved gels, measured as hydroxyprolin e, did not change after co-culture indicating that degradation of collagen may not be a major mechanism. Our findings support the hypothesis that the activity of mast cells may drive rearrangement of extracellular matrix and this and could subsequently lead to fibrosis and tissue dysfunction.