Source and characterization of hepatic macrophages in acetaminophen-induced acute liver failure in humans

Abstract

Acetaminophen‐induced acute liver failure (AALF) is associated with innate immunity activation, which contributes to the severity of hepatic injury and clinical outcome. A marked increase in hepatic macrophages (h‐mϕ) is observed in experimental models of AALF, but controversy exists regarding their role, implicating h‐mϕ in both aggravation and resolution of liver injury. The role of h‐mϕ in human AALF is virtually unexplored. We sought to investigate the role of chemokine (C‐C motif) ligand 2 (CCL2) in the recruitment of circulating monocytes to the inflamed liver and to determine how the h‐mϕ infiltrate and liver microenvironment may contribute to tissue repair versus inflammation in AALF. We evaluated circulating monocytes, their chemokine (C‐C motif) receptor 2 (CCR2) expression, and serum CCL2 levels in patients with AALF. Cell subsets and numbers of circulation‐derived (MAC387+) or resident proliferating (CD68/Ki67+) h‐mϕ in hepatic immune infiltrates were determined by immunohistochemistry. Inflammatory cytokine levels were determined in whole and laser microdissected liver tissue by proteome array. In AALF, circulating monocytes were depleted, with the lowest levels observed in patients with adverse outcomes. CCL2 levels were high in AALF serum and hepatic tissue, and circulating monocyte subsets expressed CCR2, suggesting CCL2‐dependent hepatic monocyte recruitment. Significant numbers of both MAC387+ and CD68+ h‐mϕ were found in AALF compared with control liver tissue with a high proportion expressing the proliferation marker Ki67. Levels of CCL2, CCL3, interleukin (IL)‐6, IL‐10, and transforming growth factor‐β1 were significantly elevated in AALF liver tissue relative to chronic liver disease controls. Conclusion: In AALF, the h‐mϕ population is expanded in areas of necrosis, both through proliferation of resident cells and CCL2‐dependent recruitment of circulating monocytes. The presence of h‐mϕ within an anti‐inflammatory/regenerative microenvironment indicates that they are implicated in resolution of inflammation/tissue repair processes during AALF. (HEPATOLOGY 2012)

Hepatoprotective Potential of Green Tea Extract against Experimental Hepatotoxicity in Rats

“…It might be due to acetaminophen-treated hepatic damage [28] . Further, significant (P<0.05) rise in TLC in acetaminophen-treated control group could possibly be due to the stimulation of immune system against the invading antigens and also to an IL-1β-mediated rise in the respective colony stimulating factors [29] . Treatment with NAC and GTE reversed these alterations in haematological parameters, which could be attributed to the protective effects on tissue repair and deceleration of disease progression.…”

Identification of CD68+ neutrophil granulocytes in in vitro model of acute inflammation and inflammatory bowel disease

“…The present findings need to be considered when immunohistological studies on cryostat or paraffin material from human inflammatory disorders are undertaken, as it is conceivable that a potentially erroneous impression of macrophage-derived damage is present [28][29][30].…”

Th-17 cells infiltrate the liver in human biliary atresia and are related to surgical outcome

“…Cell counting was performed according to a previously published technique (21,22) using an 'eyepiece graticule' attachment (0.25mm 2 ) to superimpose a cell counting grid (Datasights, Ltd., Middlesex, UK) onto a magnified slide image. Ten randomly chosen portal tracts and ten lobules were counted by two observers (RH, AQ).…”