CP01

Right ventricular (RV) remodeling is a severe and frequently fatal consequence of pulmonary hypertension (PH). A better understanding of the complex functional and structural adaption processes is crucial, since RV remodeling is reversible. Chronic thromboembolic pulmonary hypertension (CTEPH) is a specific form of precapillary PH and is to date the only potentially curable form of PH. Operable CTEPH may therefore serve as an ideal model for switching from chronic RV impairment to normal conditions. During the first and the second funding period, baseline biopsies (before pulmonary endarterectomy, PEA) of the RV (CTEPH_RV) from 100 CTEPH patients were collected during the surgical procedure. Moreover, 34 follow-up biopsies (12 months after PEA) and an additional number of 3 preoperative baseline biopsies were taken at the right ventricular septum (CTEPH_septum) by catheter intervention. Also, blood samples from 425 inoperable CTEPH patients who underwent BPA were collected and added to THE CP01 biobank. RNA sequencing followed by bioinformatic analysis was performed on CTEPH_RV and on CTEPH_septum. Bioinformatic analysis showed a chamber-specific gene expression pattern. We confronted microscopic morphometric data of baseline biopsies with follow-up biopsies and found that myocardial reverse remodeling is highly significant in follow-up biopsies (cooperation with A08, A06). In cooperation with project B07, several potential biomarkers for right ventricular remodeling and maladaption like SPARCL1, CILP1, Osteopontin, and galectin-3 were identified in our CTEPH and PH blood sample bank (cooperation B08). We further categorized our sample cohort in order to identify genes relevant for clinical disease evolution, rather than solely an on/off phenomenon before and after surgical intervention: we classified our CTEPH patients into three subgroups based on their clinical parameters and according to 2022 ESC/ERS guidelines: CTEPH_RV low risk, CTEPH_RV intermediate risk, and CTEPH_RV high risk. The number of differentially expressed genes (DEGs) in CTEPH_RV compared to a Control_RV cohort was 7577 genes. In CTEPH subgroups, the numbers of DEGs comparing CTEPH_RV High risk to CTEPH_RV Intermediate risk and to CTEPH_RV Low risk were 5 and 516. The number of genes comparing CTEPH_RV Intermediate versus CTEPH_RV Low risk was 100 genes. We identified (cooperation projects A01 and B07) ANKRD1 and SERPINE1 as the top regulated genes. Assessment in animal models (cooperation A05, A08) and in cardiac fibroblasts and endothelial cells suggests a key role for both genes in RV remodeling.  Increased expression of targets on a mRNA and protein level was further shown in PH animal models, and currently project B03 compares the CP01 sequencing data with the weanling rat RV hypertrophy model to assess them for further in vivo functional evaluation. Finally, an internal web-based platform was established during the second funding period for storing our OMics data, as well as all clinical parameters of our cohort. Easy access to this platform was granted to all members of CRC1213. In the next funding period, the CP01 data will be further used to 1) correlate a) specific target gene expression and b) protein expression (proteomics) with clinical CTEPH phenotypes before and after PEA in detail (e.g. cooperation A05, B02, B03, B07) and 2) establish “trans-sample” biomarkers for clinical disease evolution in our blood sample bank (Olink data (cooperations B07, B08. 3).  As further developments we will a) include CTEPD (chronic thromboembolic pulmonary disease lacking clinically manifest PH) samples in our cohort in order to differentiate transcriptomic and proteomic changes through mere increase of pulmonary arterial pressures and b) compare our samples to heathy donor heart samples, 4) submit paraffin-embedded material from our biobank to spatial gene expression analysis in order to study the topographic relation of identified highly expressed genes and histomorphological changes (fibrosis, hypertrophy). In addition, 5) sampling of right atrial cardiac tissue from CTEPH patients will allow project B10N to assess gene expression changes in atrial fibrillation in PH and 6) collection of PEA specimens with pre-obstructive pulmonary arterial wall samples and post-obstructive intima samples in order to establish endothelial cell-, smooth muscle cell- and fibroblast-cultures from patients with CTEPH as a service for various CRC projects.