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Spontaneous production of fibronectin by alveolar macrophages in patients with scleroderma
M B Kinsella1, E A Smith, K S Miller
1Department of Medicine, Medical University of South Carolina, Charleston.
Abstract:
Interstitial pulmonary fibrosis is a common manifestation of systemic sclerosis (SSc) and is a pathologic feature shared by a variety of other diseases. In these other disease processes, the glycoprotein fibronectin (FN) has been shown to be released by the alveolar macrophage, and is thus implicated in the development of fibrosis. We therefore studied the release of FN by alveolar macrophages obtained by bronchoalveolar lavage of 17 patients with SSc and 14 controls. We found that SSc alveolar macrophages released significantly more FN than did those of controls. Furthermore, the level of FN correlated positively with the level of inflammation determined by cellular analysis of lavage fluid and negatively with carbon monoxide diffusing capacity. FN may therefore play a role in the development of lung fibrosis in SSc and may be a marker of alveolitis.
Insights
Systemic sclerosis (SSc) patients show increased fibronectin (FN) release from alveolar macrophages, suggesting FN’s role in lung fibrosis and potential as an alveolitis marker.
Area of Science:
- Pulmonary Medicine
- Rheumatology
- Cellular Biology
Background:
- Interstitial pulmonary fibrosis is a common manifestation of systemic sclerosis (SSc).
- Fibronectin (FN), a glycoprotein, is implicated in fibrosis development in other lung diseases.
- Alveolar macrophages are a potential source of fibronectin in pulmonary fibrosis.
Purpose of the Study:
- To investigate fibronectin (FN) release by alveolar macrophages in patients with systemic sclerosis (SSc).
- To determine the relationship between FN levels, inflammation, and lung function in SSc.
Main Methods:
- Bronchoalveolar lavage was performed on 17 SSc patients and 14 healthy controls.
- Alveolar macrophages were isolated and their fibronectin (FN) release was measured.
- Cellular analysis of lavage fluid assessed inflammation; carbon monoxide diffusing capacity measured lung function.
Main Results:
- Alveolar macrophages from SSc patients released significantly higher levels of fibronectin (FN) compared to controls.
- Elevated FN levels positively correlated with inflammation markers in lavage fluid.
- FN levels showed a negative correlation with carbon monoxide diffusing capacity.
Conclusions:
- Fibronectin (FN) may play a significant role in the pathogenesis of lung fibrosis in systemic sclerosis (SSc).
- Fibronectin (FN) release by alveolar macrophages could serve as a biomarker for alveolitis in SSc.