IL6 and pulmonary arterial hypertension: Moreover, the inflammatory factors (IL-6, TNF-α and IL-1β) and M1 macrophage markers (iNOS) in PAH rats were all decreased, while the M2 macrophage marker (Arg1) was increased following treatment with BMSC-EVs, whereas all these changes in mRNAs and proteins were reversed after the loss of miR-200b (Fig. 4E).