Journal
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
Volume 302, Issue 3, Pages H567-H581Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.00360.2011
Keywords
coronary microcirculation; endothelial cells; pericytes; inflammation; thrombosis; polymorphonuclear leucocytes
Funding
- University of Munich
- German Phlebological Society
- Friedrich-Baur-Stiftung Munich
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Juchem G, Weiss DR, Knott M, Senftl A, Forch S, Fischlein T, Kreuzer E, Reichart B, Laufer S, Nees S. Regulation of coronary venular barrier function by blood borne inflammatory mediators and pharmacological tools: insights from novel microvascular wall models. Am J Physiol Heart Circ Physiol 302: H567-H581, 2012. First published November 11, 2011; doi:10.1152/ajpheart.00360.2011.-We hypothesized that postcapillary venules play a central role in the control of the tightness of the coronary system as a whole, particularly under inflammatory conditions. Sandwich cultures of endothelial cells and pericytes of precapillary arteriolar or postcapillary venular origin from human myocardium as models of the respective vascular walls (sandwich cultures of precapillary arteriolar or postcapillary venular origin) were exposed to thrombin and components of the acutely activatable inflammatory system, and their hydraulic conductivity (L-P) was registered. L-P of SC-PAO remained low under all conditions (3.24 +/- 0.52 . 10(-8)cm . s(-1) . cmH(2)O(-1)). In contrast, in the venular wall model, PGE(2), platelet-activating factor (PAF), leukotriene B-4 (LTB4), IL-6, and IL-8 induced a prompt, concentration-dependent, up to 10-fold increase in L-P with synergistic support when combined. PAF and LTB4 released by metabolically cooperating platelets, and polymorphonuclear leucocytes (PMNs) caused selectively venular endothelial cells to contract and to open their clefts widely. This breakdown of the barrier function was preventable and even reversible within 6-8 h by the presence of 50 mu M quercetin glucuronide (QG). LTB4 synthesis was facilitated by biochemical involvement of erythrocytes. Platelets segregated in the arterioles and PMNs in the venules of blood-perfused human myocardium (histological studies on donor hearts refused for heart transplantation). Extrapolating these findings to the coronary microcirculation in vivo would imply that the latter's complex functionality after accumulation of blood borne inflammatory mediators can change rapidly due to selective breakdown of the postcapillary venular barrier. The resulting inflammatory edema and venulo-thrombosis will severely impair myocardial performance. The protection afforded by QG could be of particular relevance in the context of cardiosurgical intervention.
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