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ABSTRACT: Background
It is now widely recognized that radiotherapy of thoracic and chest wall tumors increases the long-term risk of cardiovascular damage although the underlying mechanisms are not fully elucidated. There is increasing evidence that microvascular damage is involved. Endoglin, an accessory receptor for TGF-?1, is highly expressed in damaged endothelial cells and may play a crucial role in cell proliferation and revascularization of damaged heart tissue. We have therefore specifically examined the role of endoglin in microvascular damage and repair in the irradiated heart.Materials & methods
A single dose of 16 Gy was delivered to the heart of adult Eng(+/+) or Eng(+/-) mice and damage was evaluated at 4, 20 and 40 weeks, relative to age-matched controls. Gated single photon emission computed tomography (gSPECT) was used to measure cardiac geometry and function, and related to histo-morphology, microvascular damage (detected using immuno- and enzyme-histochemistry) and gene expression (detected by microarray and real time PCR).Results
Genes categorized according to known inflammatory and immunological related disease were less prominently regulated in irradiated Eng(+/-) mice compared to Eng(+/+) littermates. Fibrosis related genes, TGF-?1, ALK 5 and PDGF, were only upregulated in Eng(+/+) mice during the early phase of radiation-induced cardiac damage (4 weeks). In addition, only the Eng(+/+) mice showed significant upregulation of collagen deposition in the early fibrotic phase (20 weeks) after irradiation. Despite these differences in gene expression, there was no reduction in inflammatory invasion (CD45+cells) of irradiated Eng(+/-) hearts. Microvascular damage (microvascular density, alkaline phosphatase and von-Willebrand-Factor expression) was also similar in both strains.Conclusion
Eng(+/-) mice displayed impaired early inflammatory and fibrotic responses to high dose irradiation compared to Eng(+/+) littermates. This did not result in significant differences in microvascular damage or cardiac function between the strains.
SUBMITTER: Seemann I
PROVIDER: S-EPMC3722207 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
PloS one 20130724 7
<h4>Background</h4>It is now widely recognized that radiotherapy of thoracic and chest wall tumors increases the long-term risk of cardiovascular damage although the underlying mechanisms are not fully elucidated. There is increasing evidence that microvascular damage is involved. Endoglin, an accessory receptor for TGF-β1, is highly expressed in damaged endothelial cells and may play a crucial role in cell proliferation and revascularization of damaged heart tissue. We have therefore specifical ...[more]