Contribution of inflammation and impaired angiogenesis to the pathobiology of chronic thromboembolic pulmonary hypertension.

Deficient angiogenesis and systemic inflammation could be involved in the pathophysiology of chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to characterise the histopathology of pulmonary vascular lesions from 52 CTEPH patients who underwent a pulmonary endarterectomy (PEA) and investigate a potential link between clinical, biological and morphometric parameters.Collagen, elastin, fibrin, lipid, endothelial, smooth muscle and inflammatory cell content was investigated using immunohistochemistry. Qualitative changes were evaluated using severity scores. Circulating levels of inflammatory mediators were measured using ELISA.Neointima, thrombotic, recanalised and atherosclerotic lesions were found. Accumulation of macrophages, T-lymphocytes and neutrophils was found mainly in atherosclerotic and thrombotic lesions. Angiogenesis was observed in all kinds of lesions; low-scored angiogenesis predicted adverse outcome, including persistent pulmonary hypertension post-PEA, start of medical therapy and poor survival. C-reactive protein (CRP), interleukin-10, monocyte chemotactic protein-1, macrophage inflammatory protein-1α and matrix metalloproteinase (MMP)-9 were significantly elevated in CTEPH patients. Plasma CRP and MMP-9 levels correlated with neutrophil and macrophage accumulation, respectively.Enhanced systemic inflammation parallels local inflammatory cell infiltration in major pulmonary arteries at advanced stages of CTEPH. Impaired neovascularisation is associated with poor survival, start of medical treatment and persistent pulmonary hypertension post-PEA. These findings suggest that inflammation and impaired angiogenesis could contribute to the progression of the disease.

NF-κB pathway is involved in CRP-induced effects on pulmonary arterial endothelial cells in chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombofibrotic obstruction of proximal pulmonary arteries. The cellular and molecular mechanisms underlying the pathogenesis remain incompletely understood, although we recently evidenced the potential involvement of the inflammatory marker C-reactive protein (CRP). We aimed to investigate the intracellular mechanisms induced by CRP in proximal pulmonary arterial endothelial cells (PAEC). PAEC were isolated from vascular material obtained during pulmonary endarterectomy. RNA was extracted from CRP-stimulated PAEC, and first-stand cDNA was generated. A RT(2) profiler PCR Array was used to evaluate the expression of 84 key genes related to NF-κB-mediated signal transduction. CRP-induced NF-κB activation was studied. The effects of pyrrolidine-dithio-carbamate ammonium (PDTC), an inhibitor of the NF-κB pathway, were investigated on CRP-induced adhesion of monocytes to PAEC, adhesion molecule expression, endothelin-1 (ET-1), interleukin-6 (IL-6), and von Willebrand factor (vWF) secretion. Compared with nonstimulated PAEC, serotonin receptor 2B was downregulated by 25%, inhibitor of NF-κB kinase subunit epsilon (IKBKE) by 30%, and toll-like receptor-4 and -6 by 18 and 39%, respectively, in CRP-stimulated PAEC. The transcription factor FOS was threefold upregulated. CRP induced RelA/NF-κBp65 phosphorylation. PDTC dose dependently inhibited the adhesion of monocytes to CRP-stimulated PAEC. PDTC also inhibited the CRP-induced expression of ICAM-1 at the surface of PAEC. PDTC impaired the secretion of ET-1 by 18% and tended to inhibit the secretion of IL-6 by CRP-stimulated PAEC by 46%. PDTC did not inhibit the CRP-induced secretion of vWF. These results suggest an involvement of the NF-κB pathway in mediating different effects of CRP on proximal CTEPH-PAEC.

Multiplex protein profiling of bronchoalveolar lavage in idiopathic pulmonary fibrosis and hypersensitivity pneumonitis.

CONTEXT: Idiopathic pulmonary fibrosis (IPF) and chronic hypersensitivity pneumonitis (HP) are diffuse parenchymal lung diseases characterized by a mixture of inflammation and fibrosis, leading to lung destruction and finally death. AIMS: The aim of this study was to compare different pathophysiological mechanisms, such as angiogenesis, coagulation, fibrosis, tissue repair, inflammation, epithelial damage, oxidative stress, and matrix remodeling, in both disorders using bronchoalveolar lavage (BAL). METHODS: at diagnosis, patients underwent bronchoscopy with BAL and were divided into three groups: Control (n = 10), HP (n = 11), and IPF (n = 11), based on multidisciplinary approach (clinical examination, radiology, and histology): Multiplex searchlight technology was used to analyze 25 proteins representative for different pathophysiological processes: Eotaxin, basic fibroblast growth factor (FGFb), fibronectin, hepatocyte growth factor (HGF), interleukine (IL)-8, IL-12p40, IL-17, IL-23, monocyte chemotactic protein (MCP-1), macrophage-derived chemokine (MDC), myeloperoxidase (MPO), matrix metalloproteinase (MMP)-8, MMP-9, active plasminogen activating inhibitor 1 (PAI-1), pulmonary activation regulated chemokine (PARC), placental growth factor (PlGF), protein-C, receptor for advanced glycation end products (RAGE), regulated on activation normal T cells expressed and secreted (RANTES), surfactant protein-C (SP-C), transforming growth factor-ß1 (TGF-ß1), tissue inhibitor of metalloproteinase-1 (TIMP-1), tissue factor, thymic stromal lymphopoietin (TSLP), and vascular endothelial growth factor (VEGF). RESULTS: All patients suffered from decreased pulmonary function and abnormal BAL cell differential compared with control. Protein levels were increased in both IPF and HP for MMP-8 (P = 0.022), MMP-9 (P = 0.0020), MCP-1 (P = 0.0006), MDC (P = 0.0048), IL-8 (P = 0.013), MPO (P = 0.019), and protein-C (P = 0.0087), whereas VEGF was decreased (P = 0.0003) compared with control. HGF was upregulated in HP (P = 0.0089) and active PAI-1 was upregulated (P = 0.019) in IPF compared with control. Differences in expression between IPF and HP were observed for IL-12p40 (P = 0.0093) and TGF-ß1 (P = 0.0045). CONCLUSIONS: Using BAL, we demonstrated not only expected similarities but also important differences in both disorders, many related to the innate immunity. These findings provide new clues for further research in both disorders.

Characterization of proximal pulmonary arterial cells from chronic thromboembolic pulmonary hypertension patients.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is associated with proximal pulmonary artery obstruction and vascular remodeling. We hypothesized that pulmonary arterial smooth muscle (PASMC) and endothelial cells (PAEC) may actively contribute to remodeling of the proximal pulmonary vascular wall in CTEPH. Our present objective was to characterize PASMC and PAEC from large arteries of CTEPH patients and investigate their potential involvement in vascular remodeling. METHODS: Primary cultures of proximal PAEC and PASMC from patients with CTEPH, with non-thromboembolic pulmonary hypertension (PH) and lung donors have been established. PAEC and PASMC have been characterized by immunofluorescence using specific markers. Expression of smooth muscle specific markers within the pulmonary vascular wall has been studied by immunofluorescence and Western blotting. Mitogenic activity and migratory capacity of PASMC and PAEC have been investigated in vitro. RESULTS: PAEC express CD31 on their surface, von Willebrand factor in Weibel-Palade bodies and take up acetylated LDL. PASMC express various differentiation markers including α-smooth muscle actin (α-SMA), desmin and smooth muscle myosin heavy chain (SMMHC). In vascular tissue from CTEPH and non-thromboembolic PH patients, expression of α-SMA and desmin is down-regulated compared to lung donors; desmin expression is also down-regulated in vascular tissue from CTEPH compared to non-thromboembolic PH patients. A low proportion of α-SMA positive cells express desmin and SMMHC in the neointima of proximal pulmonary arteries from CTEPH patients. Serum-induced mitogenic activity of PAEC and PASMC, as well as migratory capacity of PASMC, were increased in CTEPH only. CONCLUSIONS: Modified proliferative and/or migratory responses of PASMC and PAEC in vitro, associated to a proliferative phenotype of PASMC suggest that PASMC and PAEC could contribute to proximal vascular remodeling in CTEPH.

Effects of C-reactive protein on human pulmonary vascular cells in chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterised by proximal pulmonary vascular obstruction by thrombo-fibrotic material, the origin of which has not been elucidated. Enhanced inflammation could contribute to persistent obstruction by impairing pulmonary vascular cell function in CTEPH. We investigated C-reactive protein (CRP) effects on pulmonary vascular cell function in vitro. Primary cultures of proximal pulmonary endothelial cells (ECs) and smooth muscle cells (SMCs) from CTEPH and nonthromboembolic pulmonary hypertension (PH) patients were established. Recombinant CRP effects on mitogenic activity, adhesion capacity, endothelin-1 and von Willebrand factor (vWF) secretion and intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule-1 expression were investigated in ECs and/or SMCs. Expression of the CRP receptor, lectin-like oxidised low-density lipoprotein receptor (LOX)-1, was evaluated in proximal pulmonary arterial tissue and cells by Western blotting and immunofluorescence. CRP increased CTEPH-SMC proliferation by 250%. CRP increased adhesion capacity, endothelin-1 and vWF secretion by CTEPH-ECs by 37%, 129% and 694%, respectively. CRP-induced adhesion of CTEPH-ECs to monocytes was mediated by ICAM-1. CRP had no effect on cells from nonthromboembolic PH patients, probably because of overexpression of LOX-1 in CTEPH. Local expression of CRP was detected in ECs and SMCs within pulmonary arterial tissue. CRP may contribute to persistent obstruction of proximal pulmonary arteries in CTEPH by promoting vascular remodelling, endothelial dysfunction and in situ thrombosis.