Chronic Hypoxia and Hyperoxia Modifies Morphology and Vegf Expression of the Lungs of the Developing Chicken (Gallus Gallus Domesticus) Page: 12
View a full description of this thesis.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
match the needs of the tissue (Alberts et al., 2007). Hypoxia is the best-characterized
inducer of VEGF mRNA expression (Clerici and Planes, 2009). A shortage of oxygen
increases concentrations of HIF-1 which stimulates transcription of VEGF. VEGF acts
on nearby endothelial cells and stimulates sprouting of blood vessels in order to bring
blood to the tissues, thus increasing the oxygen concentration (Alberts et al., 2007).
Among the organs in animal systems, the lung has one of the highest levels of
VEGF expression, resulting in a large number of physiological effects, including
angiogenesis and vasculogenesis (Voelkel et al., 2006). Many of these VEGF
controlled physiological effects pertain specifically to the lung during fetal development,
as well as in structural maintenance of the adult lung (Voelkel et al., 2006; Tuder et al.,
2007). Levels of fetal lung VEGF are critical because undisturbed angiogenesis and
vasculogenesis are necessary for proper vessel development which determines lung
structure maturation. The hypoxic environment of the fetal lung favors HIF-1 gene
expression which stimulates VEGF transcription. Additionally, HIF-2 controls
expression of certain VEGF isoforms during lung development (Voelkel et al., 2006).
Inhibition of fetal VEGF receptor signaling impairs blood vessel and airway branching in
the lungs, whereas, lung overexpression of fetal VEGF results in a hypervascular lung
(Tuder et al., 2007). In growing rats, inhibition of the VEGF receptor or addition of anti-
angiogenic factors resulted in reduced artery formation and failure of alveolar septation
in the lungs (Haworth and Hislop, 2003). Reduction of angiogenesis and alveolarization
in the developing rat lung, due to inhibition of the VEGF receptor, persists into
adulthood. Levels of lung VEGF in fetal development are of critical importance because
overexpression of VEGF results in lung dysmorphogenesis, whereas a decrease in lung12
Upcoming Pages
Here’s what’s next.
Search Inside
This thesis can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Thesis.
Lewallen, Melissa Anjanette. Chronic Hypoxia and Hyperoxia Modifies Morphology and Vegf Expression of the Lungs of the Developing Chicken (Gallus Gallus Domesticus), thesis, December 2012; Denton, Texas. (https://digital.library.unt.edu/ark:/67531/metadc177224/m1/19/: accessed April 23, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; .