PECAM1 and pulmonary artery enlargement: Similar results were obtained using Western blot analysis when considering the PECAM/CD31 protein (decrease by 66% at P2, p = 0.0317, n = 5 for control and PAE groups, U = 2; 50% at P5 p = 0.0397, control n = 5 and PAE n = 4, U = 1.5, Mann–Whitney test; Fig. 1F).