Therapeutic Recruitment of Thermoregulation in Humans by Selective Thermal Stimulation along the Spine

Abstract

Abstract Mammals and birds that regulate the core body temperature have an elaborate and highly effective thermoregulatory system. This system depends on the ability to move heat between the body core and surface via the convection of blood. Glabrous areas of skin, located in humans primarily on the palms, soles, ears, and selected facial sites, contain a vascular network with large-bore shunt vessels called arteriovenous anastomoses (AVAs) that have a highly dynamic and specialized control. Under conditions of core energy conservation, AVAs tightly vasoconstrict. Under conditions of core heat rejection, they vasodilate so that a significant fraction of the cardiac output can flow through them to exchange heat with the environment. A primary site of control is the preoptic anterior hypothalamus (POAH). This paper presents evidence that humans have a parallel controller peripheral to the POAH lying along the spinal cord, consistent with prior evidence in other mammalian and avian species. The ability to thermally access the spinal controller simply and safely provides an opportunity to exercise management of the body core temperature independent of the POAH to induce therapeutic hypothermia, which can have life-saving consequences for multiple medical conditions. Data are presented demonstrating the efficacy of selective thermal stimulation (STS) to the spinal cord as a means to regulate blood flow to the AVAs on demand. STS can be used in combination with dedicated heat exchangers placed onto glabrous skin to produce large heat fluxes into and out of the body for therapeutic purposes. This technology provides the basis for a new generation of medical heat transfer devices.