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Open Access Research

Defective alterations in the collagen network to prostacyclin in COPD lung fibroblasts

Anna-Karin Larsson-Callerfelt1*, Oskar Hallgren12, Annika Andersson-Sjöland1, Lena Thiman1, Johan Björklund1, Josefine Kron1, Kristian Nihlberg1, Leif Bjermer2, Claes-Göran Löfdahl2 and Gunilla Westergren-Thorsson1

Author Affiliations

1 Unit of Lung Biology, Department of Experimental Medical Sciences, BMC D12, Lund University, 221 84, Lund, Sweden

2 Department of Respiratory Medicine and Allergology, Skåne University Hospital, Lund University, Lund, Sweden

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Respiratory Research 2013, 14:21  doi:10.1186/1465-9921-14-21

Published: 14 February 2013

Abstract

Background

Prostacyclin analogs are potent vasodilators and possess anti-inflammatory properties. However, the effect of prostacyclin on extracellular matrix (ECM) in COPD is not well known. Collagen fibrils and proteoglycans are essential ECM components in the lung and fibroblasts are key players in regulating the homeostasis of ECM proteins. The aim was to study the synthesis of prostacyclin and its effect on fibroblast activity and ECM production, and in particular collagen I and the collagen-associated proteoglycans biglycan and decorin.

Methods

Parenchymal lung fibroblasts were isolated from lungs from COPD patients (GOLD stage IV) and from lungs and transbronchial biopsies from control subjects. The prostacyclin analog iloprost was used to study the effect of prostacyclin on ECM protein synthesis, migration, proliferation and contractile capacity of fibroblasts.

Results

TGF-β1 stimulation significantly increased prostacyclin synthesis in fibroblasts from COPD patients (p < 0.01), but showed no effect on fibroblasts from control subjects. Collagen I synthesis was decreased by iloprost in both control and COPD fibroblasts (p < 0.05). Conversely, iloprost significantly altered biglycan and decorin synthesis in control fibroblasts, but iloprost displayed no effect on these proteoglycans in COPD fibroblasts. Proliferation rate was reduced (p < 0.05) and contractile capacity was increased in COPD fibroblasts (p < 0.05) compared to control fibroblasts. Iloprost decreased proliferative rate in control fibroblasts (p < 0.05), whereas iloprost attenuated contraction capacity in both COPD (p < 0.01) and control fibroblasts (p < 0.05).

Conclusions

Iloprost reduced collagen I synthesis and fibroblast contractility but did not affect the collagen-associated proteoglycans or proliferation rate in fibroblasts from COPD patients. Enhanced prostacyclin production could lead to improper collagen network fibrillogenesis and a more emphysematous lung structure in severe COPD patients.

Keywords:
Chronic obstructive pulmonary disease; Collagen I; Fibroblast; Prostacyclin; Proteoglycans; Decorin; Biglycan; Proliferation; Fibroblast gel contraction; Transforming growth factor β