[Keratinocyte growth factor and Hepatocyte growth factor: their roles in alveolar epithelial repair]

The alveolar epithelium is the principal target in the course of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) and to a lesser extent in chronic reactions like pulmonary fibrosis.

Keratinocyte growth factor (KGF) and Hepatocyte growth factor (HGF) are potent growth factors for type II pneumocytes and seem to play a specific role in the process of alveolar repair.

The studies conducted by our group have demonstrated 1) that KGF and HGF are present in biologically active concentrations in human pulmonary alveoli in ALI and ARDS, 2) that in these patients as well as those with pulmonary fibrosis circulating neutrophils are an important source of HGF. HGF and KGF act within a system involving other factors such as parathyroid hormone related protein (PTHrP). PTHrP acts in an autocrine and paracrine manner to regulate the balance between proliferation and apoptosis of alveolar epithelial cells.

Our results obtained in humans suggest a beneficial role for neutrophils in the alveolar repair after acute or chronic lung injury. The experimental data suggest that use of KGF and HGF might be considered in the future in the treatment of human acute or chronic lung injury.