Endothelial communication. State of the art lecture.

Abstract

SUMMARY By virtue of its location at the interface of flowing blood and vascular tissue, the endothelial cell monolayer is in a unique position for interactions with soluble and cellular elements of the blood on one side and with component cells of the vascular tissue on the other. This brief review outlines humoral and contact-mediated endothelial communication with other cells, particularly the resident cells of the vessel wall. Evidence for gap junctional communication channels between endothelium and vascular cells is summarized and discussed in relation to endothelial ion channel activity. Myoendothelial gap junctional communication is proposed as a mechanism involved in vasorelaxation, either independent of or in concert with secreted endothelium-derived relaxing factor(s). criteria, endothelial cells interact by two general mechanisms with neighboring cells. First, the synthesis and secretion of endothelial products into the extracellular fluid are an effective humoral mechanism for interactions by diffusion and convection to other cells. Second, direct contact between endothelium and other vascular cells occurs in several morphologically defined ways, the most important of which appears to be the communicating gap junction. The types of cells involved in such communication, together with possibilities for their humoral and contact-mediated interactions, are illustrated in Figure 1

Dominant role of an endothelium‐derived hyperpolarizing factor (EDHF)‐like vasodilator in the ciliary vascular bed of the bovine isolated perfused eye

“…Moreover, evidence has been reported suggesting that the process of relaxation involves hyperpolarization of endothelial cells (Edwards et al, 1998; and consequent gap junctional transmission between endothelium and smooth muscle, resulting in smooth muscle hyperpolarization and relaxation (Davies et al, 1988;Beny, 1990;Chaytor et al, 1998). Regardless of the con¯icting evidence for the proposed candidates, there is consensus that EDHF responses are mediated by an increase in K + conductance and thus are sensitive to depolarizing solutions of K + (Adeagbo & Triggle, 1993;Corriu et al, 1996a) and by inhibitors of certain types of K + channels.…”

Differential regulation of gap junctions by proinflammatory mediators in vitro.

“…Subconfluent cultures of HUVSMCs were labeled with PKH26 (Red Fluorescent General Cell Linker Kit; Sigma Chemical Co., St. Louis, MO). 2 ϫ 10 7 HUVSMCs suspended in diluent C were mixed 1:1 with 4 M PKH26 in diluent C, incubated at 25 Њ C for 5 min. FCS (2 ml) was added to the sample, and was incubated for 1 min.…”

“…Human vascular smooth muscle cells only express Cx43 and Cx40 (5,6). Functional myoendothelial gap junctional coupling has been observed in a number of studies (7)(8)(9). Since endothelial cells are located at the interface between the blood and vascular tissue, they may act in the transfer of circulatory signals to subendothelial cells by the GJIC of second messenger molecules.…”

“…Since endothelial cells are located at the interface between the blood and vascular tissue, they may act in the transfer of circulatory signals to subendothelial cells by the GJIC of second messenger molecules. Indeed, such mechanisms may be central to controlling vascular tonus (7,8).…”

A Potential Gravity-Sensing Role of Vascular Smooth Muscle Cell Glycocalyx in Altered Gravitational Stimulation

“…It has been well established that SMCs exhibit a remarkable capability to transform between ''contractile'' and ''synthetic'' phenotypes and a continuum of states in between (Halayko and Solway, 2001). Moreover, the transformation can be modulated by mechanical factors like stretch and shear stress (Davies et al, 1988). Recently, a study in our laboratory demonstrated that VSMCs can react to gravity alteration at the single cellular level.…”