6,7,15,16 To fulfill the metabolic demands of the cancer at the very early stages of its development, the pre-existing vasculature of the host supplies oxygen and nutrients. 7,15,16 The origin and distribution of blood supply to lung carcinomas also varies depending on the type (primary or metastatic) and stage of the tumor, and can develop from either the pulmonary or bronchial circulation or both. Notably, the two lung vessel types show different pathophysiological responses, namely in hypoxia and hyperoxia, 10,11 cor pulmonale, 12 fibrosis, 13 pulmonary hypertension, 14 and cancer.
8,9 At the level of the terminal bronchioles, the bronchial vasculature often forms anastomoses with the pulmonary vasculature. Although, the left bronchial artery was small and had variable origin, which derived from the internal thoracic artery with similar branch structure as the right bronchial artery. At the back of the right main brochus, it ramifies for the different lobes of the lung. On its way to the lung, it gives off branches to the trachea, esophagus, and paratracheal and mediastinal tissue. 4,6–8 However, in mouse the right bronchial artery originates from the mammaria interna and runs downwards on the right side of the trachea. 2–5 The origin and distribution of the bronchial vasculature varies to a large extent between and among the species. 2 In addition, the lung is supplied with systemic blood flow for nourishment by the bronchial circulation, which originates from the descending aorta and supplies the wall of the airways down to the level of the respiratory region and the vasa vasorum of the large vessels. Pulmonary vessels originate from the conus arteriosus of the right ventricle and distribute blood to the capillary bed of the alveolar sac, enabling the gas exchange. 2–4 In the adult human lung, the pulmonary arteries run alongside the airways, branching with them, and decreasing in diameter. In most mammals studied, the arterial vascularization of the lung is organized in two systems: a functional part from the pulmonary arteries, and nutritive vessels from the bronchial arteries, the vasa-privata of the lung.
1 Analysis of the angio-architecture of lung tumors is necessary to identify the nutritive supplier of tumor cells and to improve the efficacy of cancer therapies. Lung cancer is among the most commonly occurring malignancies in the world and is one of the few that continues to show an increasing incidence. In this model of peripheral parenchymal malignancy, new imaging techniques allowed effective visualization of lung tumor growth and vascularization in living mice, demonstrating a pulmonary blood supply for lung tumors. Flat-panel volumetric computed tomography provided longitudinal visualization of tissue bridges between the growing tumor and the pulmonary vasculature. After filling the vessels with a vascular cast, the microanatomy of vessels being derived from the pulmonary artery was visualized with micro computed tomography. When compared to healthy lung parenchyma (13:1), Lewis lung carcinoma tumor tissue (52:1) showed a fourfold increase in pulmonary to systemic microspheres, indicating that the pulmonary arteries are the predominant tumor-feeding vessels. The relative contribution of tumor blood supply via the pulmonary and systemic arteries was studied in detail using fluorescent microspheres (10 μm). Within 7 days, histological examinations showed progressive tumor growth at the peripheral parenchymal region. To examine this in vivo, primary bronchogenic Lewis lung carcinoma cells were intratracheally instilled in C57BL/6 mice. In lung carcinomas the blood supply varies depending on tumor type and stage and can develop from pulmonary or bronchial circulation, or both.
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