1. Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, D09 YD60, Ireland
2. Tissue Engineering Research Group, Department of Anatomy, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, D02 H903, Ireland
3. Interfaculty Institute of Biochemistry, Eberhard Karls Universität Tübingen, Geschwister-Scholl-Platz 72074 Tübingen, Germany
4. Department of Respiratory & Interstitial Lung Disease, Tallaght University Hospital Tallaght, Dublin D24 NR0A, Ireland
5. School of Medicine, Trinity College Dublin, The University of Dublin, College Green, Dublin D02 PN40, Ireland