[Frontiers in Bioscience 15, 718-739, January 1, 2010]

Aging and the control of human skin blood flow

Lacy A. Holowatz1, Caitlin Thompson-Torgerson2, W. Larry Kenney1,3

1Department of Kinesiology, The Pennsylvania State University, Noll Laboratory, University Park, PA 16802, 2Department of Biomedical Engineering, Johns Hopkins Medical Institutions, Baltimore, MD 21205, 3Graduate Physiology Program, The Pennsylvania State University, Noll Laboratory, University Park, PA 16802

TABLE OF CONTENTS

1. Abstract
2. Introduction
2. Cutaneous vasoconstriction
2.1. Introduction
2.2. Reflex vasoconstriction
2.2.1. Young
2.2.2. Aging
2.2.2.1. Sympathetic autonomic dysfunction:
2.2.2.2. Impaired transmitter synthesis/release
2.2.2.3. Blunted end-organ responsiveness
2.2.3. Clinical Population
2.3. Local vasoconstriction
2.3.1. Young
2.3.2. Aging
2.3.3.Clinical Populations
2.4. Conclusions
3. Cutaneous vasodilation
3.1. Introduction
3.1.1. Aging and the integrated cardiovascular response to heat stress
3.2. Reflex Vasodilation
3.2.1.Young
3.2.2. Aging
3.2.2.1. Acetycholine
3.2.2.2. NO-dependent mechanisms
3.2.2.3. Vessel structural alterations
3.2.3. Clinical populations
3.2.3.1. Essential Hypertension
3.2.3.2. Type 2 Diabetes Mellitus
3.2.3.3. Congestive Heart Failure
3.3. Local vasodilation
3.3.1. Young
3.3.2. Aging
3.3.3. Clinical populations
3.4. Conclusions
4. References

1. ABSTRACT

Human exposure to cold and heat stimulates cutaneous vasoconstriction and vasodilation via distinct sympathetic reflex and locally mediated pathways. The mechanisms mediating cutaneous vasoconstriction and vasodilation are impaired with primary aging, rendering the aged more vulnerable to hypothermia and cardiovascular complications from heat-related illness, respectively. This paper highlights recent findings discussing how age-related decrements in sympathetic neurotransmission contribute directly to thermoregulatory impairments, whereas changes in local intracellular signaling suggest a more generalized age-associated vascular dysfunction.