The requirements of metabolizing tissue are both continuous and variable; accordingly, the microvasculature serving that tissue must be similarly dynamic. Just as it is recognized that males and females of the same species have differing metabolic requirements, is it not likely that the microvasculature serving these tissues will differ by sex? This section focusing on the constituents of the microcirculation identifies what is known presently about the role sex plays in matching metabolic demand with microvascular function and areas requiring additional study. Many of the identified sex differences are subtle and easily ignored. In the aggregate, though, they can profoundly alter phenotype, especially under stressful conditions including pregnancy, exercise, and disease states ranging from diabetes to heart failure. Although the features presently identified to "have sex" range from differences in growth, morphology, protein expression, and intracellular signaling, males and females alike achieve homeostasis, likely by different means. Studies of microvascular sexual dimorphism are also identifying age as an independent but interacting factor requiring additional attention. Overall, attempting to ignore either sex and/or age is inappropriate and will prevent the design and implementation of appropriate interventions to present, ameliorate, or correct microvascular dysfunction.
Keywords: Aquaporin; Arterioles; Barrier function; Blood flow regulation; Capillaries; Coronary microvascular dysfunction; Endothelium; Fibrinolysis; Fluid homeostasis; Glycocalyx; Hydrostatic pressure; Hypertension; Lymphatics; Microcirculation; Microvascular network; Myogenic response; Orthostatic intolerance; Pericyte; Peripheral resistance; Pregnancy; Rarefaction; Sepsis; Sex difference; Sexual dimorphism; Syndecan-1; Vascular homeostasis; Venules.