Acute pulmonary embolism generally resolves within 6 months. However, if thrombus is infected venous thrombi transform into fibrotic vascular obstructions leading to chronic deep vein thrombosis and/or chronic thromboembolic pulmonary hypertension (CTEPH), but precise mechanisms remain unclear. Neutrophils are crucial in sequestering pathogens, therefore, the role of neutrophil extracellular traps (NETs) in chronic thrombosis was investigated. Since chronic pulmonary thrombotic obstructions are biologically identical to chronic deep venous thrombi, the murine inferior vena cava ligation model was used to study the transformation of acute to chronic thrombus. Mice with staphylococcal infection presented with larger thrombi containing more neutrophils and NETs, but less resolution. Targeting NETs with DNase1 diminished fibrosis, and promoted thrombus resolution. For translational studies in humans, we focused on patients with CTEPH, a severe type of deep venous and pulmonary artery fibrotic obstruction following thrombosis. Neutrophils, markers of neutrophil activation, and NET formation were increased in CTEPH patients. NETs promoted the differentiation of monocytes to activated fibroblasts with the same cellular phenotype as fibroblasts from CTEPH vascular occlusions. RNA sequencing of fibroblasts isolated from thrombo-endarterectomy specimens and pulmonary artery biopsies revealed transforming growth factor-β (TGF-β) as the central regulator, a phenotype which was replicated in mice with fibroblast-specific TGF-β overactivity. Our findings uncover a role of neutrophil-mediated inflammation to enhance TGF-β signaling which leads to fibrotic thrombus remodeling. Targeting thrombus NETs with DNases may serve as a new therapeutic concept to treat thrombosis and prevent its sequelae.

BackgroundVarious immunotherapeutic approaches have been used for the treatment of cancer. A number of natural compounds are designed to repair, stimulate, or enhance the immune system response. Among them are the hemocyanins (Hcs) - extracellular copper proteins isolated from different arthropod and mollusc species. Hcs are oxygen transporter molecules and normally are freely dissolved in the hemolymph of these animals. Hemocyanins are very promising class of anti-cancer therapeutics due to their immunogenic properties and the absence of toxicity or side effects. KLH (Megathura crenulata hemocyanin) is the most studied molecule of this group setting a standard for natural carrier protein for small molecules and has been used in anti-tumor clinical trials.ResultsThe Hcs isolated from marine snail Rapana thomasiana (RtH) and the terrestrial snail Helix pomatia (HpH) express strong in vivo anti-cancer and anti-proliferative effects in the developed by us murine model of colon carcinoma. The immunization with RtH and HpH prolonged the survival of treated animals, improve humoral anti-cancer response and moderate the manifestation of C-26 carcinoma symptoms as tumor growth, splenomegaly and lung metastasis appearance.ConclusionHemocyanins are used so far for therapy of superficial bladder cancer and murine melanoma models. Our findings demonstrate a potential anti-cancer effect of hemocyanins on a murine model of colon carcinoma suggesting their use for immunotherapy of different types of cancer.

Objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by one or more of the following features: intraluminal thrombus organization, fibrous stenosis, and complete obliteration of major pulmonary arteries, amenable to significant improvement by pulmonary endarterectomy (PEA) or balloon pulmonary angioplasty, and medical treatments with vasodilators. Because treatment practices and outcomes differ in Europe versus Japan, we hypothesized that population-based characteristics of pulmonary vascular phenotypes may exist in Austria compared with Japan. The objectives of this study were to analyze clinical characteristics, hemodynamics, and PEA specimens in consecutive patients with CTEPH undergoing PEA in Austria and Japan.Methods: Clinical features, hemodynamics, and PEA specimens were collected and analyzed in patients with CTEPH undergoing PEA, and clinical features and hemodynamics were collected and analyzed in patients with notoperated CTEPH and in patients with nonthromboembolic pulmonary arterial hypertension.Results: Apart from key differences between Austrian and Japanese patients regarding body size, lung function vital capacity, cardiac output, and serum high-density lipoprotein levels, Austrian patients were more likely to be obese, have greater hematocrits and greater white blood cells counts, greater C-reactive protein levels, and significantly elevated serum myeloperoxidase levels compared with Japanese patients with CTEPH. Analysis of PEA specimens demonstrated more proximal thrombus and more fresh red thrombus components in Austrian patients.Conclusions: This study documents an inflammatory thrombotic phenotype in Austrian compared with Japanese patients with CTEPH that may be a determinant of differential treatment outcomes.