Cysteinyl leukotriene receptor antagonist regulates vascular permeability by reducing vascular endothelial growth factor expression

Inflammation of the asthmatic airway is usually accompanied by increased vascular permeability and plasma exudation. Cysteinyl leukotrienes (cysLTs) potently elicit increased vascular permeability in airways, leading to airway edema. Vascular endothelial growth factor (VEGF) is 1 of the most potent proangiogenic cytokines and also increases vascular permeability so that plasma proteins can leak into the extravascular space. However, the mechanisms by which cysLTs induce increased vascular permeability are not clearly understood. An aim of the current study was to determine the role of the cysLTs, more specifically in the increase of vascular permeability. We used a BALB/c mouse model of allergic asthma to examine effects of cysLT receptor antagonists on bronchial inflammation and airway hyperresponsiveness, more specifically on the increase of vascular permeability. These mice develop the following typical pathophysiological features of asthma in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased vascular permeability, and increased levels of VEGF. Administration of cysLT receptor antagonists markedly reduced plasma extravasation and VEGF levels in allergen-induced asthmatic lungs. These results indicate that cysLT receptor antagonists modulate vascular permeability by reducing VEGF expression and suggest that cysLT receptor may regulate the VEGF expression.