Microscopy Image Dataset for Deep Learning-Based Quantitative Assessment of Pulmonary Vascular Changes.

Pulmonary hypertension (PH) is a syndrome complex that accompanies a number of diseases of different etiologies, associated with basic mechanisms of structural and functional changes of the pulmonary circulation vessels and revealed pressure increasing in the pulmonary artery. The structural changes in the pulmonary circulation vessels are the main limiting factor determining the prognosis of patients with PH. Thickening and irreversible deposition of collagen in the pulmonary artery branches walls leads to rapid disease progression and a therapy effectiveness decreasing. In this regard, histological examination of the pulmonary circulation vessels is critical both in preclinical studies and clinical practice. However, measurements of quantitative parameters such as the average vessel outer diameter, the vessel walls area, and the hypertrophy index claimed significant time investment and the requirement for specialist training to analyze micrographs. A dataset of pulmonary circulation vessels for pathology assessment using semantic segmentation techniques based on deep-learning is presented in this work. 609 original microphotographs of vessels, numerical data from experts' measurements, and microphotographs with outlines of these measurements for each of the vessels are presented. Furthermore, here we cite an example of a deep learning pipeline using the U-Net semantic segmentation model to extract vascular regions. The presented database will be useful for the development of new software solutions for the analysis of histological micrograph.

Sympathetic Denervation and Pharmacological Stimulation of Parasympathetic Nervous System Prevent Pulmonary Vascular Bed Remodeling in Rat Model of Chronic Thromboembolic Pulmonary Hypertension.

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.

Inhibition of JAK1,2 Prevents Fibrotic Remodeling of Pulmonary Vascular Bed and Improves Outcomes in the Rat Model of Chronic Thromboembolic Pulmonary Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism with poor clinical outcomes. Therapeutic approaches to prevention of fibrotic remodeling of the pulmonary vascular bed in CTEPH are limited. In this work, we tested the hypothesis that Janus kinase 1/2 (JAK1/2) inhibition with ruxolitinib might prevent and attenuate CTEPH in a rat model. CTEPH was induced by repeated embolization of the pulmonary artery with partially biodegradable 180 ± 30 µm alginate microspheres. Two weeks after the last injection of microspheres, ruxolitinib was administered orally at doses of 0.86, 2.58, and 4.28 mg/kg per day for 4 weeks. Prednisolone (1.475 mg/kg, i.m.) was used as a reference drug. Ruxolitinib in all doses as well as prednisolone reduced pulmonary vascular wall hypertrophy. Ruxolitinib at a dose of 2.58 mg/kg and prednisolone reduced vascular wall fibrosis. Prednisolone treatment resulted in decreased right ventricular systolic pressure. Pulmonary vascular resistance was lower in the prednisolone and ruxolitinib (4.28 mg/kg) groups in comparison with the placebo group. The plasma level of brain natriuretic peptide was lower in groups receiving ruxolitinib at doses of 2.58 and 4.28 mg/kg versus placebo. This study demonstrated that JAK1/2 inhibitor ruxolitinib dose-dependently reduced pulmonary vascular remodeling, thereby preventing CTEPH formation in rats.

Mechanisms of Regenerative Potential Activation in Cardiac Mesenchymal Cells.

Recovery of the contractile function of the heart and the regeneration of the myocardium after ischemic injury are contemporary issues in regenerative medicine and cell biology. This study aimed to analyze early transcriptional events in cardiac tissue after infarction and to explore the cell population that can be isolated from myocardial tissue. We induced myocardial infarction in Wistar rats by permanent ligation of the left coronary artery and showed a change in the expression pattern of Notch-associated genes and Bmp2/Runx2 in post-MI tissues using RNA sequencing and RT-PCR. We obtained primary cardiac mesenchymal cell (CMC) cultures from postinfarction myocardium by enzymatic dissociation of tissues, which retained part of the activation stimulus and had a pronounced proliferative potential, assessed using a "xCELLigence" real-time system. Hypoxia in vitro also causes healthy CMCs to overexpress Notch-associated genes and Bmp2/Runx2. Exogenous activation of the Notch signaling pathway by lentiviral transduction of healthy CMCs resulted in a dose-dependent activation of the Runx2 transcription factor but did not affect the activity of the Bmp2 factor. Thus, the results of this study showed that acute hypoxic stress could cause short-term activation of the embryonic signaling pathways Notch and Bmp in CMCs, and this interaction is closely related to the processes of early myocardial remodeling after a heart attack. The ability to correctly modulate and control the corresponding signals in the heart can help increase the regenerative capacity of the myocardium before the formation of fibrotic conditions.

Rodent models of pulmonary embolism and chronic thromboembolic pulmonary hypertension.

Pulmonary embolism (PE) is the third most prevalent cardiovascular disease. It is associated with high in-hospital mortality and the development of acute and chronic complications. New approaches aimed at improving the prognosis of patients with PE are largely dependent on reliable animal models. Mice, rats, hamsters, and rabbits, are currently most commonly used for PE modeling because of their ethical acceptability and economic feasibility. This article provides an overview of the main approaches to PE modeling, and the advantages and disadvantages of each method. Special attention is paid to experimental endpoints, including morphological, functional, and molecular endpoints. All approaches to PE modeling can be broadly divided into three main groups: 1) induction of thromboembolism, either by thrombus formation in vivo or by injection of in vitro prepared blood clots; 2) introduction of particles of non-thrombotic origin; and 3) surgical procedures. The choice of a specific model and animal species is determined based on the objectives of the study. Rodent models of chronic thromboembolic pulmonary hypertension (CTEPH), which is the most devastating complication of PE, are also described. CTEPH models are especially challenging because of insufficient knowledge about the pathogenesis and high fibrinolytic activity of rodent plasma. The CTEPH model should demonstrate a persistent increase in pulmonary artery pressure and stable reduction of the vascular bed due to recurrent embolism. Based on the analysis of available evidence, one might conclude that currently, there is no single optimal method for modeling PE and CTEPH.

Analysis of Models of Doxorubicin-Induced Cardiomyopathy in Rats and Mice. A Modern View From the Perspective of the Pathophysiologist and the Clinician.

Today the pharmacological possibilities of treating cancer are expanding and as a result, life expectancy is increasing against the background of chemotherapy and supportive treatment. In the conditions of successful antitumor treatment, complications associated with its toxic effect on healthy tissues and organs began to come to the fore. Anthracycline cardiomyopathy was the first serious cardiovascular complication to draw the attention of oncologists and cardiologists around the world. Anthracycline drugs such as doxorubicin, epirubicin, idarubicin are still widely used in oncological practice to treat a wide range of solid and hematological malignancies. Doxorubicin-induced cardiomyopathy is closely associated with an increase in oxidative stress, as evidenced by reactive oxygen species (ROS) nduced damage such as lipid peroxidation, and decreased levels of antioxidants. Myofibrillar destruction and dysregulation of intracellular calcium are also important mechanisms, usually associated with doxorubicin-induced cardiotoxicity. Despite the abundance of data on various mechanisms involved in the implementation of doxorubicin-induced cardiotoxicity, a final understanding of the mechanism of the development of doxorubicin cardiomyopathy has not yet been formed. It poses the most significant challenges to the development of new methods of prevention and treatment, as well as to the unambiguous choice of a specific treatment regimen using the existing pharmacological tools. In order to resolve these issues new models that could reflect the development of the chemotherapy drugs effects are needed. In this review we have summarized and analyzed information on the main existing models of doxorubicin cardiomyopathy using small laboratory animals. In addition, this paper discusses further areas of research devoted to the development and validation of new improved models of doxorubicin cardiomyopathy suitable both for studying the mechanisms of its implementation and for the preclinical drugs effectiveness assessment.

Model of Chronic Thromboembolic Pulmonary Hypertension in Rats Caused by Repeated Intravenous Administration of Partially Biodegradable Sodium Alginate Microspheres.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare and life-threatening complication of pulmonary embolism. As existing animal models of CTEPH do not fully recapitulate complex disease pathophysiology, we report a new rat model for CTEPH evoked by repetitive embolization of the distal pulmonary artery branches with partially biodegradable alginate microspheres (MSs). MSs (180 ± 28 µm) were intravenously administered eight times at 4-day intervals; control animals received saline. The validity of the model was confirmed using transthoracic echocardiography, exercise testing, catheterization of the right ventricle, and histological examination of the lung and heart. The animals in the CTEPH group demonstrated a stable increase in right ventricular systolic pressure (RVSP) and decreased exercise tolerance. Histopathological examination revealed advanced medial hypertrophy in the small pulmonary arteries associated with fibrosis. The diameter of the main pulmonary artery was significantly larger in the CTEPH group than in the control group. Marinobufagenin and endothelin-1 serum levels were significantly elevated in rats with CTEPH. In conclusion, repetitive administration of alginate MSs in rats resulted in CTEPH development characterized by specific lung vasculature remodeling, reduced exercise tolerance, and a persistent rise in RVSP. The developed model can be used for pre-clinical testing of promising drug candidates.

Rat Left Ventricular Cardiomyocytes Characterization in the Process of Postinfarction Myocardial Remodeling.

Ischemic lesions of the heart, including myocardial infarction, are the most common pathologies of human cardiovascular system. Despite all the research and achievements of medicine in this field, the mortality from this disease remains heavy. Therefore, studying of processes occurring in the myocardium in the early and late postinfarction periods remains important. Rat left ventricular cardiomyocyte (CMC) ploidy, hypertrophy, hyperplasia, and ultrastructure were investigated in 2, 6, and 26 weeks after experimental myocardial infarction, caused by permanent ligation of left coronary artery. Cytofluorimetric study of CMC ploidy revealed no difference between normal, sham-operated, and infarcted animals for all the tested stages. However, interference microscopy indicated significant changes in cells size. CMC dry mass of infarcted rats in 2 weeks after surgery was 1.5 times lower than in control and sham operated groups. Electron microscopy analysis of CMC revealed disruption of sarcomere structure. However, in 6 weeks after surgery CMC dry mass was 1.6 times higher than in control. In 26 weeks after myocardial infarction CMC dry mass exceeded control only in peri-infarction zone. Cell counting showed that the number of left ventricular CMC, reduced as a result of myocardial infarction, was not restored during myocardial remodeling. © 2019 International Society for Advancement of Cytometry.