Expression of transforming growth factors beta (1, 2, 3) and connective tissue growth factor in the peripheral lung from GOLD stage 1-2 COPD patients and smokers with normal lung function

Transforming growth factor (TGF)-ß1 is highly expressed in epithelium and macrophages of small airways in patients with chronic obstructive pulmonary disease (COPD). It is a potent inducer of fibrosis, partly via the release of the potent fibrogenic mediator, connective tissue growth factor (CTGF). Two other members (2 and 3) of TGF family may also be pro-fibrogenics in vitro. However, the expression of TGF2 and 3, and CTGF in the peripheral lung of patients with mild to moderate chronic obstructive pulmonary disease (COPD) has not been previously studied. We have investigated the expression of TGF1, 2, 3, and CTGF in lung parenchyma of smokers with mild to moderate (GOLD stages 1 and 2) COPD (n=16) compared with age-matched smokers with normal lung function (n=18). Peripheral lung tissue was obtained during lung resection surgery. We examined formalin-fixed paraffin-embedded lung sections. By immunohistochemistry (IHC) we detected TGF1, 2, 3, and CTGF expression mainly in bronchiolar epithelial cells and macrophages. The semiquantitative IHC scoring for TGF1, 2, 3, and CTGF in bronchiolar epithelial cells and endoalveolar macrophages was not significantly different between COPD patients and smokers with normal lung function. These data suggest that TGF1, 2, 3, and CTGF expression are not increased in the peripheral lung of GOLD stage 1 and 2 COPD patients.