VEGFA and idiopathic pulmonary fibrosis: Patients with IPF had decreased levels of endothelial progenitor cells and increased levels of compensatory proangiogenic mediator VEGF, a key cytokine of angiogenesis, which may contribute to the growth of alveolar epithelial type II cells and the production of surfactant, angiogenesis, and anti-apoptotic effects [13,34].