Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2011;6(6):e21381.
doi: 10.1371/journal.pone.0021381. Epub 2011 Jun 22.

Interleukin-8 is activated in patients with chronic liver diseases and associated with hepatic macrophage accumulation in human liver fibrosis

Henning W Zimmermann  1 , Sebastian Seidler, Nikolaus Gassler, Jacob Nattermann, Tom Luedde, Christian Trautwein, Frank Tacke
Affiliations

Interleukin-8 is activated in patients with chronic liver diseases and associated with hepatic macrophage accumulation in human liver fibrosis

Henning W Zimmermann et al. PLoS One. 2011.

Abstract

Background: Interleukin-8 (IL-8, CXCL8) is a potent chemoattractant for neutrophils and contributes to acute liver inflammation. Much less is known about IL-8 in chronic liver diseases (CLD), but elevated levels were reported from alcoholic and hepatitis C-related CLD. We investigated the regulation of IL-8, its receptors CXCR1 and CXCR2 and possible IL-8 responding cells in CLD patients.

Methodology: Serum IL-8 levels were measured in CLD patients (n = 200) and healthy controls (n = 141). Intrahepatic IL-8, CXCR1 and CXCR2 gene expression was quantified from liver samples (n = 41), alongside immunohistochemical neutrophil (MPO) and macrophage (CD68) stainings. CXCR1 and CXCR2 expression was analyzed on purified monocytes from patients (n = 111) and controls (n = 31). In vitro analyses explored IL-8 secretion by different leukocyte subsets.

Principal findings: IL-8 serum levels were significantly increased in CLD patients, especially in end-stage cirrhosis. Interestingly, patients with cholestatic diseases exhibited highest IL-8 serum concentrations. IL-8 correlated with liver function, inflammatory cytokines and non-invasive fibrosis markers. Intrahepatically, IL-8 and CXCR1 expression were strongly up-regulated. However, intrahepatic IL-8 could only be associated to neutrophil infiltration in patients with primary biliary cirrhosis (PBC). In non-cholestatic cirrhosis, increased IL-8 and CXCR1 levels were associated with hepatic macrophage accumulation. In line, CXCR1, but not CXCR2 or CXCR3, expression was increased on circulating monocytes from cirrhotic patients. Moreover, monocyte-derived macrophages from CLD patients, especially the non-classical CD16⁺ subtype, displayed enhanced IL-8 secretion in vitro.

Conclusions: IL-8 is strongly activated in CLD, thus likely contributing to hepatic inflammation. Our study suggests a novel role of IL-8 for recruitment and activation of hepatic macrophages via CXCR1 in human liver cirrhosis.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Serum IL-8 levels in healthy controls and patients with chronic liver disease.
(A) Serum IL-8 levels are significantly increased in patients compared to healthy controls. (B) Cirrhotic patients show higher IL-8 serum levels than non-cirrhotics. (C) Dissecting the various stages of CLD revealed that IL-8 levels are highest in end-stage liver disease. (D) Patients with underlying alcoholic and biliary/autoimmune liver diseases showed higher IL-8 serum concentrations than viral hepatitis or other causes of CLD. (E) To normalize for the stage of cirrhosis, IL-8 serum levels were divided by the Child-Pugh score points. Elevated IL-8 in cholestatic and alcoholic liver diseases remained significant. CLD, chronic liver disease; AIH, autoimmune hepatitis.
Figure 2
Figure 2. Intrahepatic IL-8 and IL-8 receptor gene expression.
Gene expression levels of IL-8 (A) and the IL-8 receptors CXCR1 (B) and CXCR2 (C) were assessed from liver tissue by real-time qPCR and are displayed as fold induction. Samples from CLD patients were divided according to fibrosis stage (middle graphs) and to disease etiology (right graphs). Tissue from acute liver failure (ALF) was analyzed in parallel for comparison. CLD, chronic liver disease; ctrl, control; PBC, primary biliary cirrhosis; ALD, alcoholic liver disease; ALF, acute liver failure.
Figure 3
Figure 3. Immunohistochemical analysis of neutrophil and macrophage accumulation in chronic liver disease.
(A) Myeloperoxidase (MPO) staining was performed to detect neutrophils within the liver. Upper panels depict representative images of neutrophil accumulation in PBC (left column) and HCV (right column) with F4 fibrosis at 200× magnification, lower panels magnify the periportal region of upper panels. MPO-positive neutrophils accumulate in PBC in comparison to ALD, HCV and HBV, whereas degree of fibrosis was not indicative for neutrophil count within the liver. Neutrophil cell infiltrate predominate within the cirrhotic fibres in periportal regions whereas remaining parenchyma was absent for neutrophil invasion. (B) CD68+ cells indicating macrophages accumulate according to severity of liver disease irrespective of underlying etiology. Images represent exemplarily distribution of CD68+ in F0 fibrosis (AIH) and F4 fibrosis (PBC). Scale bars represent 100 µm. AIH, autoimmune hepatitis; PBC, primary biliary cirrhosis; ALD, alcoholic liver disease.
Figure 4
Figure 4. CXCR1 and CXCR2 mRNA and protein expression on circulating monocytes.
(A) Monocytes were purified from whole blood by MACS with anti-CD14 antibodies, revealing purities above 95%. Representative FACS analysis before and after purification is shown. (B–C) Gene expression levels of the IL-8 receptors CXCR1 (B) and CXCR2 (C) were assessed from purified circulating monocytes of patients and controls and are displayed as relative expression levels. CLD, chronic liver disease. (D) CXCR1 and CXCR2 expression was also measured on a protein level by FACS. Representative plots from a healthy control (left) and patients with alcoholic Child C cirrhosis (right) are shown; pre-gating on CD14+ monocytes to exclude CXCR1 expression by neutrophils. (E) Representative histograms showing how mean fluorescence intensity (MFI) was assessed: isotype control staining was subtracted from CXCR1 expression on circulating CD14+ monocytes from healthy controls or patients. (F) Comparison of monocytic CXCR1 protein expression between healthy controls and patients with liver cirrhosis. Peripheral blood neutrophils served as a positive control for CXCR1 and CXCR2 staining (not shown).
Figure 5
Figure 5. IL-8 secretion by monocyte-derived macrophages.
(A) Macrophages were derived from blood monocytes of healthy donors (n = 20) and patients with Child B or C liver cirrhosis (n = 15). IL-8 secretion was measured in supernatant after 2 days of culture with autologous serum (white bars) as well as after stimulation with LPS (grey). Representative bright field microscopy pictures of cultured macrophages are displayed. (B) CD14+CD16+ monocytes, CD14++CD16− monocytes and lymphocytes were isolated from healthy donors. IL-8 secretion was measured in supernatant after 5 days of culture with autologous serum (white bars) as well as after stimulation with LPS (grey).
See this image and copyright information in PMC

References

    1. Schuppan D, Afdhal NH. Liver cirrhosis. Lancet. 2008;371:838–851. - PMC - PubMed
    1. Iredale JP. Models of liver fibrosis: exploring the dynamic nature of inflammation and repair in a solid organ. J Clin Invest. 2007;117:539–548. - PMC - PubMed
    1. Karlmark KR, Wasmuth HE, Trautwein C, Tacke F. Chemokine-directed immune cell infiltration in acute and chronic liver disease. Expert Rev Gastroenterol Hepatol. 2008;2:233–242. - PubMed
    1. Zimmermann HW, Seidler S, Nattermann J, Gassler N, Hellerbrand C, et al. Functional contribution of elevated circulating and hepatic non-classical CD14CD16 monocytes to inflammation and human liver fibrosis. PLoS One. 2010;5:e11049. - PMC - PubMed
    1. Karlmark KR, Weiskirchen R, Zimmermann HW, Gassler N, Ginhoux F, et al. Hepatic recruitment of the inflammatory Gr1+ monocyte subset upon liver injury promotes hepatic fibrosis. Hepatology. 2009;50:261–274. - PubMed

Publication types

MeSH terms