Alveolar type I cells as diagnostic markers for acute lung injury

Recent work in an Oklahoma State University lab on type I cells in the alveoli has opened up a new field of investigation.

Most exchange of oxygen and carbon dioxide between the body and the environment occurs in the alveoli. Approximately 95% of the alveolar surface is covered by alveolar type I cells, with the remainder made up of type II cells. Type II cells and their role in surfactant secretion have been studied extensively, but much less is known about the role of type I cells, in part due to technical difficulties in obtaining a highly purified type I cell preparation.

The current study uses a powerful DNA microarray technique to obtain the gene expression profile of highly purified type I cells, and then uses the data to infer a novel physiological function for this cell type. In addition to their role in gas exchange, the results suggest that type I cells protect the alveolus from oxidative injury. Moreover, many type I cell-specific genes were identified that could potentially serve as diagnostic markers of acute lung injury, thereby opening up a new field of investigation in alveolar cell biology.

This study began in 2002 in the Lung Biology and Toxicology Laboratory at the Oklahoma State University. When asked about the potential implications of the study, Dr. Lin Liu, director of the lab and one of the authors of the study, said, "With the availability of primary alveolar type I cells and the gene expression profile of this cell type, I believe that more novel functions of type I cells in the lung and new therapeutic targets for pulmonary diseases will be discovered in the near future".