J.M. Dominguez II, R.D. Prisby, B.J. Behnke, M.R. Allen, and M.D. Delp
Div Exercise Physiology and Center for Interdisciplinary Research Cardiovascular Sciences, West Virginia Univ Sch Medicine, Morgantown, West Virginia USA
Dept Applied Physiology & Kinesiology, Univ Florida, Gainesville, Florida USA
Dept Anat & Cell Biol, Indiana University Sch Medicine, Indianapolis, Indiana USA
Introduction: The purpose of this study was to determine whether regional blood flow (microspheres) in the femur is diminished with aging, and whether a reduction in flow is associated with impaired endothelium-dependent vasodilation.
Materials and Methods: Blood flow and PNA endothelium-dependent vasodilation was measured in young (4-6 months old) and aged (24-26 months old) male Fischer-344 rats.
Results: Blood flow in the aged rats was ~25% lower in femoral bone and 45% lower in diaphyseal marrow. Endothelium-dependent vasodilation was lower with old age (young: 83 6% maximal relaxation; aged: 62 5% maximal relaxation) and was mediated through impairment of the NOS signaling pathway, which resulted in a lower nitric oxide bioavailability (young: 168 56 nM nitric oxide; aged: 50 7 nM nitric oxide).
Discussion: Such age-related changes in bone perfusion and nitric oxide signaling could impact clinical bone loss, increase risk of fracture, and impair fracture healing in the elderly.