With an aging population, increasing focus is on treating conditions that develop in later life, such as atherosclerosis and its progression to ischemia, a condition in which the blood flow (and thus oxygen) is restricted to a part of the body. Many times ischemia is found in the lower extremities in older individuals. Older patients are thought to have less tolerance to acute ischemia than younger patients, often leading to poor outcomes resulting in increased risk of mortality and amputation.
According to the American Vascular Association (AVA) Resident Research Prize Paper, presented at the 62nd Annual Meeting of the Society for Vascular Surgery, older patients also may have less ability to repair of vessels and arteries after acute injury, similar to other effects of aging.
Study author and Resident Research Prize recipient Tormod S. Westvik, MD, a resident at the Yale University School of Medicine, New Haven, Conn., described how researchers created a model mimicking severe leg ischemia, to examine the effects of age and whether it depresses the regeneration of blood vessels and arteries in severe acute limb ischemia.
Dr. Westvik explained in the lab 15 young adult (three months) and 20 aged (18 months) mice underwent right common iliac artery and vein ligation and transection. Data were collected on days 0, 7 and 14. After severe hindlimb ischemia, both groups of mice had a similar degree of decreased perfusion and all became ischemic. Older mice had a significantly impaired arteriogenesis and functional recovery after 14 days. Aged mice also had increased capillary density and endiothelial progenitor cell numbers compared to young mice, but diminished collateral supply to the ischemic limb.
"On a biological level, both groups of mice produced the components necessary to form new vessels. However, only the young animals succeeded in arranging these components into functioning vessels which improved blood flow to the injured leg," said Dr. Westvik.
"These results suggest that strategies to stimulate arteriogenesis may complement those that increase angiogenesis, thus may result in improved relief of ischemia."
"Based on the results in our study, we propose that further investigations should be aimed at improving the ability of older animals (and subsequently patients) to arrange these available components into functioning vessels, thus improving the outcome after acute ischemia," said Dr. Westvik.