Human mast cell basic fibroblast growth factor in pulmonary fibrotic disorders

Area of Science:

• Pulmonary Medicine
• Cell Biology
• Immunology

Background:

• Mast cells (MCs) are prevalent in fibrotic tissues, but their role in fibrosis development is unclear.
• Emerging evidence suggests MCs may produce basic fibroblast growth factor (bFGF), a key fibrogenic mediator.

Purpose of the Study:

• To investigate the hypothesis that MC-derived bFGF contributes to the fibrotic response in human interstitial lung diseases.
• To determine the presence, localization, and clinical relevance of bFGF in MCs within diseased lung tissue.

Main Methods:

• Analysis of lung tissue, bronchoalveolar lavage fluid, and serum from patients with idiopathic pulmonary fibrosis, chronic beryllium disease, sarcoidosis, and controls.
• Immunohistochemistry to identify bFGF-expressing cells, morphometric analysis of fibrosis, and measurement of bFGF levels.
• In vitro studies using a human MC line to confirm bFGF expression and localization.

Main Results:

• MCs were the predominant bFGF-expressing cells in the lung interstitium, particularly in idiopathic pulmonary fibrosis.
• The distribution of bFGF+ MCs correlated with extracellular matrix deposition and fibrosis extent.
• Elevated bFGF levels in bronchoalveolar lavage fluid and serum were associated with disease severity and gas exchange impairment.

Conclusions:

• MCs are a significant source of bFGF in the fibrotic lung.
• MC-derived bFGF plays a role in the pathogenesis of human interstitial lung diseases and is linked to clinical outcomes.