Most α-SMA positive cells in the media from lung donors, non-thromboembolic PH and CTEPH patients express desmin (Figure 6A, B, C) and SMMHC (Figure 6E, F, G), whereas only a low proportion of SMC in the neointima from CTEPH patients were co-stained for α-SMA and desmin (Figure 6D) or α-SMA and SMMHC (Figure 6H). This evidence concerns the gene ACTA1 and chronic thromboembolic pulmonary hypertension.