In ARDS which is damaged?

In ARDS,alveolar capillary endothelial cells & type 1 pneumocytes(alveolar epithelial cells) are damaged/injured,leading to the loss of the normally tight alveolar barrier to fluid and macromolecules.As a result,edema fluid rich in protein accumulates in the interstitial & alveolar spaces.Condensed plasma proteins aggregate in the air spaces with cellular debris and dysfunctional pulmonary surfactant to form hyaline membrane whorls. Reference:Harrison's Medicine-20th edition,page no:2032