Increased P-selectin gene expression in the liver vasculature and its role in the pathophysiology of neutrophil-induced liver injury in murine endotoxin shock

Abstract

We studied the role of P-selectin, an adhesion molecule known to be important for neutrophil localization to sites of inflammation, in a model of inflammatory liver injury. Male C3Heb/ FeJ (ET-sensitive) mice treated with 700 mg/kg galactosamine and 100 g/kg Salmonella abortus equi endotoxin (Gal/ET), murine tumor necrosis factor ␣ (TNF-␣, 15 g/kg), or interleukin-1 (IL-1, 13-23 g/kg), showed increased P-selectin mRNA levels in the liver. In contrast, C3H/HeJ (ET-resistant) mice responded only to cytokines with P-selectin mRNA formation. Whereas no P-selectin expression was detectable in control livers, there was temporary staining of endothelium in large blood vessels but not in sinusoids between 3 and 5 h after ET, TNF-␣, or IL-1 treatment. Severe liver injury induced by Gal/ET at 7 h was not inhibited by an anti-P-selectin antibody in C3Heb/FeJ mice or in P-selectin-deficient animals. Sequestration of neutrophils in sinusoids, i.e. those neutrophils that have been identified as critical for the injury, was not affected by the antibody or in P-selectindeficient mice. However, the temporary margination in portal and post-sinusoidal venules was reduced by 75% in anti-P-selectin antibody-treated animals and by 51% in P-selectin-deficient mice. We conclude that hepatic P-selectin gene transcription in vivo involves cytokines. However, blocking P-selectin neither attenuated sinusoidal neutrophil sequestration nor prevented neutrophil-induced liver injury during endotoxin shock but attenuated neutrophil margination in larger vessels. Thus, our data demonstrate similarities and fundamental differences in the requirement for adhesion molecules to localize neutrophils in the liver vasculature compared to other organs during an inflammatory response.

Molecular mechanisms of tumor necrosis factorα–stimulated leukocyte recruitment into the murine hepatic circulation

“…7 Finally, despite the reduction in venular recruitment, ␣ 4 -integrin-antibody treatment had absolutely no impact on the number of stationary leukocytes in the sinusoids. Essani et al 35 have shown that despite an increase in VCAM-1 expression on sinusoidal endothelium and Kupffer cells in response to endotoxin stimulation (associated with increased ␣ 4 -integrin expression on circulating neutrophils), blocking VCAM-1 had no effect on the number of leukocytes accumulated in the sinusoids. 33 Although this latter study could be explained by the potential recruitment via selectins, our work extends this view to suggest that no known tethering molecules (selectins or ␣ 4 -integrin) play a dominant role in the liver sinusoids.…”

“…This concentration of TNF has been shown to increase P-selectin expression in the portal and central venules of the liver. 6 The TNF-␣ response was first compared between the wild-type animals and mice deficient in P-selectin. In another set of P-selectindeficient animals, a baseline recording was made and the animal was injected with an anti-E-selectin antibody (Ab) (9A9, 100 µg intravenously [IV]) (a gift from Dr. B. Wolitsky).…”

“…4 Mediators such as LTC 4 or endotoxin, which induced selectin-dependent rolling in numerous vascular beds, induced selectin-independent adhesion in the sinusoids. 5,6 It is unclear whether this was a result of the low shear rates and physical trapping within the liver microcirculation or the fact that the selectins are not required for leukocyte-endothelial cell interactions in the liver. One possible explanation for a lack of a selectin role may be a dominant role for ␣ 4 -integrin, which has been shown to support rolling and adhesion in vitro, albeit at lower shear rates.…”

Inhibition of macrophages with gadolinium chloride alters intercellular adhesion molecule-1 expression in the liver during acute endotoxemia in rats

“…7-9 Increased quantities of soluble circulating adhesion molecules have also been detected in various models of liver injury. 2,7,8,10 These findings, together with the observation that liver injury is abrogated by administration of antibodies to certain cell adhesion molecules, [4][5][6]11 suggest that they play a role in hepatotoxicity associated with inflammation.Endotoxin is a bacterially derived product known to induce liver injury at toxic doses. 12 We have previously demonstrated that acute endotoxemia is associated with an increase in the number of macrophages in the liver.…”

“…Cell adhesion molecules are a group of membraneassociated proteins present on leukocytes, endothelial cells, and parenchymal cells that facilitate monocyte adherence and emigration out of the blood and into the tissue. Expression of several different classes of cell adhesion molecules have been reported to be up-regulated on liver cells after exposure of animals to hepatotoxic doses of alcohol 1,2 or endotoxin, 3,4 following reperfusion injury, 5,6 and in humans with acute and chronic inflammatory liver diseases. [7][8][9] Increased quantities of soluble circulating adhesion molecules have also been detected in various models of liver injury.…”