Biochemical consequences of mechanical forces generated by distention and distortion.

This review includes a number of concepts: (1) mechanical forces are transmitted to cell membranes by adhesion complexes between solid elements in the extracellular environment and the cytoskeleton; (2) the adhesion complexes require inhibition of proteases to maintain their adhesion; and (3) hydrostatic pressure is a mechanical stress on solid elements in the tissues, and it is controlled by the microcirculation and lymphatic system. Hypotheses include the following: (1) mechanical forces act on the cell membrane and induce inhibitors of proteases, thereby maintaining the adhesion complexes; (2) the transduction of chemical signals--protease inhibition--is more flexible in young cells, wounds, and psoriasis. In old tissues, protease inhibition is more sustained; and (3) cell shape, cell migration, and mitosis are in part controlled by such mechanisms. These hypotheses are supported by evidence from the literature and observations from my experience and that of many co-workers in the fields of microcirculation, lymphatic systems, angiogenesis, wound healing, and proteases.