Vascular dysfunction in aged mice contributes to persistent lung fibrosis.

Area of Science:

• Pulmonary Medicine
• Vascular Biology
• Aging Research

Background:

• Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease associated with aging and impaired repair.
• The role of lung vasculature in fibrosis resolution remains unclear.
• Vascular alterations are increasingly recognized in IPF pathogenesis.

Purpose of the Study:

• To investigate the role of endothelial cells (ECs) in lung fibrosis resolution in young versus aged mice.
• To determine the contribution of endothelial nitric oxide synthase (eNOS) to lung repair and fibrosis.
• To explore the therapeutic potential of targeting vascular function in IPF.

Main Methods:

• Intratracheal bleomycin administration in young and aged mice.
• Analysis of lung capillary density and EC gene expression.
• Investigated eNOS deficiency in young mice and its effect on fibrosis.
• Assessed the impact of NO signaling on human lung fibroblasts and ECs.

Main Results:

• Aged mice showed capillary rarefaction and altered EC gene expression post-injury, unlike young mice.
• eNOS was transiently upregulated in young mice but not aged mice following injury.
• eNOS deficiency in young mice led to non-resolving lung fibrosis, mimicking aged mice.
• NO signaling reduced pro-fibrotic gene expression in human lung fibroblasts and ECs.

Conclusions:

• Persistent lung fibrosis in aging is associated with capillary rarefaction and impaired eNOS expression.
• eNOS plays a critical role in resolving lung fibrosis.
• Targeting vascular function, particularly eNOS, may be a promising therapeutic strategy for IPF and aging-related lung diseases.