Objectives: The role of extracellular matrix collagen biomarkers in chronic thromboembolic pulmonary hypertension (CTEPH) is not well known. Our goal was to investigate the matrix metalloproteinase (MMP)-2 and -9 protein levels in patients with CTETH.
Methods: This is a prospective, cross-sectional study. Patients with CTETH who underwent pulmonary endarterectomy comprise group 1, and the control group included patients who underwent lung surgery without pulmonary hypertension (group 2) between March 2020 and March 2021. In addition to serum levels of MMP-9, the pulmonary endarterectomy and control pulmonary artery tissue samples were measured by the enzyme-linked immunosorbent assay 4pl, cubic, quadratic and Western blot techniques. Levels of MMP-2, which consist of pro MMP-2/ß-actin and active MMP-2/ß-actin and MMP-9/ß-actin, were measured only in the tissue samples.
Results: Forty-eight patients were enrolled consecutively in group 1 (n: 24) and group 2 (n: 24). The serum concentrations of MMP-9 were similar in both groups. Similarly, a comparison of tissue sample levels of pro MMP-2/ß-actin (P = 0.496) and active MMP-2/ß-actin (P = 0.216) showed no significant difference between the groups. The tissue samples from patients with CTETH had significantly lower amounts of MMP-9/ß-actin compared to the control group (P = 0.001).
Conclusions: This study indicates that serum levels of extracellular matrix collagen biomarkers were similar in patients with CTETH who were candidates for surgery and in patients who had non-pulmonary hypertension who underwent lung surgery. Differences in levels of MMP-9/ß-actin in tissue samples may play a role in pulmonary vascular remodelling in operable patients.
Keywords: chronic thromboembolic pulmonary hypertension; matrix metalloproteinases 2 and 9; pulmonary endarterectomy.
© The Author(s) 2023. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.