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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Carbon Tetrachloride, Cyclooxygenase Inhibitors, Disease Models, Animal, Enzyme Inhibitors, Heme Oxygenase (Decyclizing), Indomethacin, Liver Cirrhosis, Male, Mesenteric Arteries, Mesoporphyrins, NG-Nitroarginine Methyl Ester, Nitric Oxide Synthase, Phenylephrine, Rats, Rats, Wistar, Regional Blood Flow, Splanchnic Circulation, Statistics, Nonparametric, Stress, Mechanical, Vasoconstriction, Vasoconstrictor Agents, Vasodilation.
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Is mesenteric arteries responsiveness to acute variations of wall shear stress impaired in rats with liver cirrhosis? Context: In liver cirrhosis, excessive splanchnic vasodilation is due to abnormal synthesis of endogenous vasodilators and to decreased sensitivity to vasoconstrictors. The role of mechanical stimuli such as wall shear stress (WSS) on splanchnic circulation remains unclear. The aim of this study was to assess the vasodilation induced by wall shear stress (WSS) and acute changes in blood flow in the mesenteric arteries in an experimental model of liver cirrhosis. The effect of acute changes in intraluminal flow (0, 10, and 20 μl/min) and WSS on the diameter of the mesenteric arteries (diameters <500 μm) of control and cirrhotic rats was assessed, at baseline and after the inhibition of nitric oxide synthase, cyclooxygenase and hemeoxygenase. Concentration-response curves to phenylephrine were also obtained. In controls, the increase in intraluminal flow led to a significant increase in arterial diameter (p < 0.05), while WSS remained stable; the effect was maintained in vessels pre-constricted with phenylephrine, blocked by the exposure to indomethacin and L-NAME and restored by the subsequent addition of chromium mesoporphyrin (p < 0.05). In cirrhotic arteries, arterial diameters did not change in response to acute increase in flow, neither at baseline nor after exposure to indomethacin and L-NAME, while WSS increased (p < 0.01). Responsiveness to flow was partially restored (p < 0.05) after exposure of the arteries to chromium mesoporphyrin in addition to indomethacin and L-NAME.
assistant
Arteries from cirrhotic rats showed an abolished responsiveness to acute variations in flow, which exposes the mesenteric endothelium to sudden variations in WSS. Final Decision: yes