Chronic thromboembolic pulmonary hypertension (CTEPH) develops in 1.5–2.0% of patients experiencing pulmonary embolism (PE) and is characterized by stable pulmonary artery obstruction, heart failure, and poor prognosis. Little is known about involvement of autonomic nervous system (ANS) in the mechanisms of CTEPH. This study was aimed at evaluation of the effect of vagal and sympathetic denervation, as well as stimulation of the parasympathetic nervous system, on the outcomes of CTEPH in rats. CTEPH was induced by multiple intravenous injections of alginate microspheres. Sympathetic and vagal denervation was performed using unilateral surgical ablation of the stellate ganglion and vagotomy, respectively. Stimulation of the parasympathetic nervous system was carried out by administering pyridostigmine. The effect of neuromodulatory effects was assessed in terms of hemodynamics, histology, and gene expression. The results demonstrated the key role of ANS in the development of CTEPH. Sympathetic denervation as well as parasympathetic stimulation resulted in attenuated pulmonary vascular remodeling. These salutary changes were associated with altered MMP2 and TIMP1 expression in the lung and decreased FGFb level in the blood. Unilateral vagotomy had no effect on physiological and morphological outcomes of the study. The data obtained contribute to the identification of new therapeutic targets for CTEPH treatment.

Chronic thromboembolic pulmonary hypertension (CTEPH) remains a severe disease with low survival rates in inoperable patients, despite advances in treatment. The molecular mechanisms underlying the pathogenesis of CTEPH are not fully understood, necessitating further research to identify new therapeutic targets. Although numerous animal models of CTEPH have been developed, demonstrating their clinical relevance requires establishing molecular bioequivalence with human pathophysiological processes, particularly through matching gene expression profiles. The aim of this study was to analyze differential gene expression in rat lung tissues following CTEPH modeling via alginate microsphere administration and to assess the applicability of this model for developing and investigating new therapeutic strategies for CTEPH. CTEPH was modeled in Wistar rats via repeated intravenous injections of biodegradable alginate microspheres. The transcriptional profile in lung tissue samples collected from CTEPH rats at weeks 2 and 6, as well as from control rats, was analyzed using high-throughput RNA sequencing technology. Differentially expressed genes (DEGs) were identified via DESeq2. Gene expression changes were validated by reverse transcription polymerase chain reaction (RT-PCR). Transcriptomic analysis revealed that CTEPH modeling at week 2 upregulated the expression of inflammation-related genes, whereas at week 6, it downregulated the expression of extracellular matrix-related genes. Transcription factor analysis showed a predominant regulation of DEG promoters by Cys2-His2 zinc finger (C2H2 ZF) proteins Zfp278 and Klf5, suggesting their involvement in the cellular response during CTEPH development. RT-PCR analysis of Cav1, Eng, vWF, and Gja5 gene expression in a larger sample set of lung tissue confirmed its dynamics detected in the transcriptomic analysis. Here, we revealed dynamic transcriptional changes during CTEPH development in rats, including the dysregulation of extracellular matrix-, inflammation-, and endothelial dysfunction-related genes, consistent with the current understanding of CTEPH pathogenesis. The data obtained demonstrate the comparability of the developed rat model with the clinical course of CTEPH in humans at the transcriptional level, supporting its relevance for preclinical research.