Kupffer cell-initiated remote hepatic injury following bilateral hindlimb ischemia is complement dependent

Abstract

Intravital fluorescence microscopy was applied to the livers of male Wistar rats to test the hypothesis that complement mobilization stimulates Kupffer cells and subsequently initiates hepatic injury after hindlimb ischemia/reperfusion (I/R). Following 3 h of limb reperfusion, hepatocellular viability (serum levels of alanine transaminase and cell death via propidium iodide labeling) decreased significantly from levels in sham-operated animals. Inhibition of complement mobilization with soluble complement receptor type 1 (20 mg/kg body wt) and interruption of Kupffer cell function with GdCl(3) (1 mg/100g body wt) resulted in significant hepatocellular protection. Although the effects of hindlimb I/R on hepatic microvascular perfusion were manifest as increased heterogeneity, both complement inhibition and suppression of Kupffer cell function resulted in marked improvements. No additional hepatocellular protection and microvascular improvements were provided by combining the interventions. Furthermore, inhibition of complement mobilization significantly depressed Kupffer cell phagocytosis by 42% following limb reperfusion. These results suggest that the stimulation of Kupffer cells via complement mobilization is necessary but is not the only factor contributing to the early pathogenesis of hepatic injury following hindlimb I/R.

Inhalation of carbon monoxide prevents liver injury and inflammation following hind limb ischemia/reperfusion

“…In the present study, remote organ injury resulting from hind limb I/R led to disturbances in the sinusoidal microcirculation, increased inflammation, and increased hepatocellular injury, confirming previous results (11,12,24). Interestingly, inhalation of CO (250 ppm) either reversed or significantly reduced such changes, whereas inhalation in naïve mice had no effect.…”

“…Using intravital video microscopy, we showed that induction of heme oxygenase (HO-1), the rate-limiting enzyme in the catabolism of heme into carbon monoxide (CO), biliverdin, and free iron (7), prevented hepatocellular death, microvascular perfusion deficits, and inflammation that results following hind limb ischemia/reperfusion (I/R) (8)(9)(10)(11)(12). It is now generally accepted that increased HO activity is protective in several models of hepatic stress.…”

Protective effects of a potent c5a receptor antagonist on experimental acute limb ischemia-reperfusion in rats

“…We have recently shown an elevation of serum TNF-␣ levels following gut I/R, and kidney tissue TNF-␣ levels following renal I/R, and blockade of these increased levels to I/R by the same C5a antagonist used in the present study [29,30]. In the present study, we found that the C5a antagonist significantly blocked the rise in liver TNF-␣, indicating that C5a is also involved in the elevation of TNF-␣ following limb I/R, perhaps through the direct activation of Kupffer cells located in the liver [9,10]. This inhibition of circulating and tissue levels of TNF-␣ by C5a antagonists has been shown by us and others in a variety of inflammatory disease models where complement activation is involved [27][28][29][30][31]48].…”

“…The involvement of the complement system in limb I/R injury has been clearly demonstrated in numerous studies utilizing C5-deficient mice, an anti-C5a antibody, and the soluble complement C1 receptor, sCR1 [5,10,19,[22][23][24][25]. These studies have shown that complement activation during ischemia and reperfusion leads to the development of local muscle damage and remote lung and liver injury during the reperfusion phase.…”

Inhibition of haem oxygenase activity increases leukocyte accumulation in the liver following limb ischaemia-reperfusion in mice

“…While models of limb I-R associated with hypotension have shown evidence of remote injury in the lung (Welbourn et al 1991), heart and kidney (Walker, 1991), recent studies using a normotensive model of limb I-R have shown remote injury in the intestine (Corson et al 1992) and most recently within the liver (Brock et al 1999(Brock et al , 2001). …”