Bovine distal pulmonary arterial media is composed of a uniform population of well-differentiated smooth muscle cells with low proliferative capabilities

The media of the normal bovine main pulmonary artery (MPA) is composed of phenotypically heterogeneous smooth muscle cells (SMC) with markedly different proliferative capabilities in response to serum, mitogens, and hypoxia. Little, however, is known of the SMC phenotype in distal pulmonary arteries...

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Bibliographic Details
Published in:American journal of physiology. Lung cellular and molecular physiology 2003-10, Vol.29 (4), p.L819-L828
Main Authors: STIEBELLEHNER, Leopold, FRID, Maria G, REEVES, John T, LOW, Robert B, GNANASEKHARAN, Meena, STENMARK, Kurt R
Format: Article
Language:English
Subjects:
Biological and medical sciences
Cells
Hypertension
Medical sciences
Pneumology
Pulmonary arteries
Pulmonary hypertension. Acute cor pulmonale. Pulmonary embolism. Pulmonary vascular diseases
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Summary:The media of the normal bovine main pulmonary artery (MPA) is composed of phenotypically heterogeneous smooth muscle cells (SMC) with markedly different proliferative capabilities in response to serum, mitogens, and hypoxia. Little, however, is known of the SMC phenotype in distal pulmonary arteries (PA), particularly in arterioles, which regulate the pulmonary circulation. With a panel of muscle-specific antibodies against -smooth muscle (SM)-actin, SM-myosin heavy chains (SM-MHC), SM-MHC-B isoform, desmin, and meta-vinculin, we demonstrate a progressive increase in phenotypic uniformity and level of differentiation of SMC along the proximal-to-distal axis of normal adult bovine pulmonary circulation so that the media of distal PA (1,500- to 100-µm diameter) is composed of a phenotypically uniform population of "well-differentiated" SMC. Similarly, when isolated and assessed in vitro, distal PA-SMC is composed of a single, uniform population of differentiated SMC that exhibited minimal growth responses to a variety of mitogens while their cell size increased substantially in response to serum. Their growth was inhibited by hypoxic exposure under all conditions tested. Distal PA-SMC also differed from MPA-SMC by exhibiting a distinct pattern of DNA synthesis in response to serum and mitogens. Thus, in contrast to the MPA, distal PA media is composed of an apparently uniform population of well-differentiated SMC that are proliferation resistant and have a substantial capacity to hypertrophy in response to growth-promoting stimuli. We thus speculate that distinct SMC phenotypes present in distal vs. proximal PA may confer different response mechanisms during remodeling in conditions such as hypertension. [PUBLICATION ABSTRACT]
ISSN:1040-0605
1522-1504