Angiogenesis, the formation (sprouting) of new blood vessels from pre-existing vasculature, is impaired in aging. This impairment is detrimental to the healing of wounds and revascularization of ischemic tissues. Inspite of its clinical importance, the cellular mechanisms that regulate angiogenic sprouting, and the microvascular endothelial cells (ECs) and mural cells that comprise newly formed vessels, are poorly understood in aging. The details of angiogenic sprouting are difficult to observe in vivo due to tissue thickness and the presence of stromal and inflammatory cells. Moreover, the tip region of each sprout, which is a critical area of investigation, is rarely found in tissue sections. We propose that vascular segments cultured ex vivo are the most effective means to study the details of angiogenic sprouts. In this model, vascular segments are isolated from tissues with an abundant microcirculation (e.g., adipose) and placed in 3-dimensional collagen gels that simulate interstitial matrix in vivo. The segments serve as """"""""parent vessels"""""""" from which sprouts are generated and imaged. We propose to use microvessels from young and aged mice, in conjunction with novel culture methods and modern image analysis, to refine and extend the capabilities of the microvascular sprout model. Our hypothesis is that aged sprouts will show an increase in the number of mural cells, relative to ECs, and that the formation of cell-cell contacts is delayed. We also postulate that deposition of basement membrane will proceed normally, but there will be deficient matrix turnover at sprout tips.
Aim 1 will define the cellular components, their morphology, orientation, and the influence of migration, relative to proliferation.
Aim 2 will determine the influence of age on formation of cell-cell contacts, the deposition of basement membrane proteins, and the expression/activity of matrix degrading metalloproteinases. The results will define the key points of deficient microvascular growth in the aged and also develop the microvessel sprout model into a highly useful tool for studies of vascular growth in general.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AG024458-02
Application #
7074692
Study Section
Special Emphasis Panel (ZRG1-CMAD (01))
Program Officer
Kohanski, Ronald A
Project Start
2005-07-01
Project End
2008-06-30
Budget Start
2006-07-01
Budget End
2008-06-30
Support Year
2
Fiscal Year
2006
Total Cost
$171,845
Indirect Cost
Name
University of Washington
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Damodarasamy, Mamatha; Johnson, Richard S; Bentov, Itay et al. (2014) Hyaluronan enhances wound repair and increases collagen III in aged dermal wounds. Wound Repair Regen 22:521-6
Reed, May J; Vernon, Robert B (2012) Miniaturized assays of angiogenesis in vitro. Methods Mol Biol 843:87-98
Reed, May J; Damodarasamy, Mamatha; Vernon, Robert B (2011) Angiogenesis In Vitro Utilizing Murine Vascular Explants in Miniaturized 3-Dimensional Collagen Gels. Open Circ Vasc J 4:12-17
Damodarasamy, Mamatha; Vernon, Robert B; Karres, Nathan et al. (2010) Collagen extracts derived from young and aged mice demonstrate different structural properties and cellular effects in three-dimensional gels. J Gerontol A Biol Sci Med Sci 65:209-18
Reed, May J; Eyman, Daniel; Karres, Nathan (2008) Nitric oxide effects on the function of aged cells ex vivo and in vivo. In Vivo 22:673-9
Reed, May J; Karres, Nathan; Eyman, Daniel et al. (2007) Culture of murine aortic explants in 3-dimensional extracellular matrix: a novel, miniaturized assay of angiogenesis in vitro. Microvasc Res 73:248-52