| Previous studies show cardiogenic edema fluid (EF) increases in vitro Na+ transport by fetal distal lung epithelia (FDLE) (J. Physiol, 2002). The present study investigates the effect of EF on Na+ and fluid transport in the adult lung. EF-treated primary cultures of alveolar type II (ATII) epithelium had a dose-dependent increase in amiloride-insensitive Na+ transport. Treatment of ATII with high or low doses of EF did not alter amiloride-sensitive Na+ transport; however, moderate doses increased it. Plasma did not have a similar effect. Globulins-treated cells demonstrated a conversion of amiloride-sensitive to amiloride-insensitive current without increasing total current. Changes in ENaC mRNA levels did not always parallel changes in treatment-induced bioelectric properties. We conclude that cardiogenic EF increases ion transport by ATII, predominately via increased amiloride-insensitive Isc. These studies point towards new therapeutic approaches for patients with congestive heart failure or adult respiratory distress syndrome-induced pulmonary edema. |
