Pulmonary hypertension (PH) is a group of fatal diseases, including idiopathic pulmonary arterial hypertension (IPAH) and chronic thromboembolic PH (CTEPH), which are rare diseases with treatment options. Although there are suggested molecular mechanisms for IPAH, the pathogenesis of CTEPH remains unclear.

This study hypothesized that PH-related genes and their post-transcriptional regulators, miRNAs, may show specific expression patterns in IPAH and CTEPH patients.

In this study, healthy controls (n = 12), IPAH (n = 15), and CTEPH (n = 12) patients were recruited. The expression levels of PH-related ABCA3, ATP13A3, BMPR1A, BMPR2, KCNK3, NOTCH1, SMAD9, SOX17, and TET2 genes, along with hsa-miR-30a-5p, hsa-miR-210–3p, hsa-miR-155–5p, and hsa-miR-126–3p were determined using qRT-PCR. The associations between expression levels and clinical measurements were assessed.

ABCA3 expression was decreased in IPAH (p = 0.007), while SMAD9 expression was elevated in CTEPH patients (p = 0.012). miR-210–3p and miR-126–3p were increased in IPAH and CTEPH, while miR-30a-5p was increased in IPAH patients (p = 0.005). Moreover, systolic pulmonary artery pressure showed significant negative correlation with ATP13A3, BMPR1A, BMPR2, KCNK3, SMAD9, SOX17, and TET2 expression in IPAH patients, while NOTCH1 expression levels were positively correlated with pulmonary artery wedge pressure in CTEPH group.

The study identifies distinct gene and miRNA expression profiles in IPAH and CTEPH patients. Specifically, ABCA3 is downregulated in IPAH, while SMAD9 is upregulated in CTEPH, suggesting potential markers. Additionally, dysregulated miRNAs highlight the importance of post-transcriptional regulation. The correlations between gene expression and clinical parameters emphasize their prognostic value. These results represent preliminary findings and need further validation in larger cohorts.