Angiotensin II binding to human embryonic lung fibroblasts causes transient changes in cytosolic calcium and promotes fibrin gel contraction.

ABSTRACT

Contraction of granulation tissue is promoted by the peptide vasoconstrictor angiotensin II (AII), which presumably acts on the fibroblasts present in granulation tissue. Direct effects of AII on fibroblast contraction were examined using an in vitro fibrin gel contraction model. Fibrin gels were formed by mixing cultured human embryonic lung fibroblasts with fibrinogen, in the presence of thrombin and measurement of gel volume was used to determine the extent of fibrin gel contraction by fibroblasts. AII stimulated an additional 28.5 +/- 3% decrease in gel size after 24 hr, AII is also shown to specifically bind to human embryonic lung fibroblasts and stimulate rapid transient increases in cytosolic calcium. AII stimulates contraction of human embryonic lung fibroblasts as reflected by acceleration of fibrin gel contraction. Fibrin clot contraction contributes to extra cellular matrix reorganization during initial stages of wound repair and AII-stimulated fibroblast contraction may accelerate this process.