Calcitonin gene-related peptide increases microcirculation after mechanically induced ischemia in an experimental island flap

Abstract

Vasoconstriction, as a result of mechanical manipulation of blood vessels during microsurgery, may produce a decrease in blood supply and endanger flap viability. A study was undertaken to determine the effects of the topical vasodilator calcitonin gene-related peptide on the microcirculation of flaps after mechanically induced ischemia. A neurovascular island flap based on the superficial epigastric vessels was raised in 42 rats. Blood cell flux in the flap was recorded continuously with a laser Doppler flux meter. The feeding artery was pinched to induce vasospasm, and different concentrations of calcitonin gene-related peptide (10(-7), 10(-8), 10(-9), 10(-10) mol) or a control of sodium chloride 0.9% was applied topically to relieve the ischemia. Results showed that calcitonin gene-related peptide at a concentration of 10(-7) mol significantly shortened the time to reach 50% of the original blood cell flux values (270 +/- 123 seconds) and significantly increased the number of flaps in which the blood cell flux values were restored to prestress levels within 30 minutes. The data support the conclusion that, in this model, topical calcitonin gene-related peptide at the concentration of 10(-7) mol was effective in promoting recovery of the microcirculation after mechanically induced ischemia, without the adverse effects associated with other commonly used vasodilators.