ID3 and pulmonary fibrosis: The effect of Id1 and 3 expression levels on angiogenesis and microvascular remodeling following adult tissue injury has not been a subject of investigation with the exception of studies of bleomycin induced lung injury [25] that showed increased endothelial cell apoptosis and lung fibrosis in Id1 knockout mice and dermal wound healing [26] that showed impaired angiogenesis and granulation tissue formation in endothelial specific Id1 and Id3 knockout mice.