Abstract
Background and AimsBy blocking TNFα-related effects, thalidomide not only inhibits hepatic fibrogenesis but improves peripheral vasodilatation and portal hypertension in cirrhotic rats. Nonetheless, the investigation of thalidomide's effects on splanchnic and collateral microcirculation has been limited. Our study explored the roles of intestinal and mesenteric TNFα along with inflammasome-related pathway in relation to cirrhosis and the splanchnic/collateral microcirculation.MethodsUsing in vivo and in vitro approaches, mechanisms of the effects of thalidomide on intestinal and mesenteric inflammatory, vasodilatory and angiogenic cascades-related abnormalities were explored in cirrhotic rats that had received 1-month thalidomide (C-T) treatment.ResultsIn cirrhotic rats, high tumor necrosis factor (TNF)α, vascular endothelial growth factor (VEGF) and nitric oxide (NO)x levels were associated with the NOD-like receptors protein 3 (NLRP3), IL-1β and caspase-1 inflammasome over-expression in splenorenal shunt and mesenteric tissues. The thalidomide-related inhibition of mesenteric and splenorenal shunt inflammasome expression was accompanied by a significantly decreased intestinal mucosal injury and inflammasome immunohistochemical staining expression. Suppression of various angiogenic cascades, namely VEGF-NOS-NO, was paralleled by a decrease in mesenteric angiogenesis as detected by CD31 immunofluorescence staining and by reduced portosystemic shunting (PSS) in C-T rats. The down-regulation of the mesenteric and collateral vasodilatory VEGF-NOS-NO cascades resulted in a correction of vasoconstrictive hypo-responsiveness and in an attenuation of vasodilatory hyper-responsiveness when analyzed by in situ perfusion of the superior mesenteric arterial (SMA) and portosystemic collaterals. There was also a decrease in SMA blood flow and an increase in SMA resistance in the C-T rats. Additionally, acute incubation with thalidomide abolished TNFα-augmented VEGF-mediated migration of and tube formation of human umbilical vein endothelial cells, which was accompanied by corresponding changes in inflammatory and angiogenic substances release.ConclusionsThe suppression of inflammasome over-expression by chronic thalidomide treatment ameliorates inflammatory, angiogenic and vasodilatory cascades-related pathogenic changes in the splanchnic and collateral microcirculation of cirrhotic rats. Thalidomide seems to be a promising agent that might bring about beneficial changes to the disarrangements of peripheral, hepatic, splanchnic and collateral systems in cirrhosis.
Highlights
Up-regulated vascular endothelial growth factor (VEGF) and nitric oxide (NO)-mediated splanchnic angiogenesis and vasodilatation, together with an attempt to divert the stagnant portal blood flow into the systemic circulation, are important for the development of hyperdynamic syndrome in cirrhotic portal hypertensive (PH) rats [1,2,3,4,5,6,7].When there is a chronic inflammatory disease like cirrhosis present, TNFα brings about the stimulation of VEGF and NO-derived angiogenesis in order to supply nutrients and oxygen to the affected tissue [5,8]
High tumor necrosis factor (TNF)α, vascular endothelial growth factor (VEGF) and nitric oxide (NO)x levels were associated with the NOD-like receptors protein 3 (NLRP3), IL-1β and caspase-1 inflammasome over-expression in splenorenal shunt and mesenteric tissues
The down-regulation of the mesenteric and collateral vasodilatory VEGF-NOS-NO cascades resulted in a correction of vasoconstrictive hypo-responsiveness and in an attenuation of vasodilatory hyper-responsiveness when analyzed by in situ perfusion of the superior mesenteric arterial (SMA) and portosystemic collaterals
Summary
Up-regulated vascular endothelial growth factor (VEGF) and nitric oxide (NO)-mediated splanchnic angiogenesis and vasodilatation, together with an attempt to divert the stagnant portal blood flow into the systemic circulation, are important for the development of hyperdynamic syndrome in cirrhotic portal hypertensive (PH) rats [1,2,3,4,5,6,7].When there is a chronic inflammatory disease like cirrhosis present, TNFα brings about the stimulation of VEGF and NO-derived angiogenesis in order to supply nutrients and oxygen to the affected tissue [5,8]. Up-regulated vascular endothelial growth factor (VEGF) and nitric oxide (NO)-mediated splanchnic angiogenesis and vasodilatation, together with an attempt to divert the stagnant portal blood flow into the systemic circulation, are important for the development of hyperdynamic syndrome in cirrhotic portal hypertensive (PH) rats [1,2,3,4,5,6,7]. TNFα mediates the activation of the inflammasome and contributes to the progression of chronic inflammation [10,11,12]. Via an IL-1β independent mechanism, the NOD-like receptors proteins (NLRPs) inflammasome contributes to VEGF-mediated angiogenesis [16,17]. Our study explored the roles of intestinal and mesenteric TNFα along with inflammasome-related pathway in relation to cirrhosis and the splanchnic/collateral microcirculation
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