MPO and acute respiratory distress syndrome: Interstitial edema, collagen fiber content (Table 1), levels of IL-6, TNF-α, and TGF-β in lung tissue homogenate (Figure 4), MPO activity in lung tissue (Figure 5), and gene expression of types I and III procollagen (Figure 6) were increased in Control-ALI compared to Control-SAL, but not in Obese-ALI compared to Obese-SAL.