Page 146 - Read Online

appear to affect the cytokine production may be stranded positive-sense RNA virus and is one of the
associated with susceptibility to HCV infection and major causes for acute hepatitis worldwide. C-X-C
resistance to combined antiviral therapy. [6] motif ligand 8 (CXCL-8) is a small multifunctional
proinflammatory chemokine. It was reported
Mitochondria are a major source of ROS under recently that HEV infection significantly upregulates
physiologic conditions, because 2% to 3% of the CXCL-8 gene expression. [67]
O consumed is converted to O 2 •− mainly by auto
−

2
oxidation of ubisemiquinone which transfer electrons The severity of HEV infection and associated adverse
from complexes I and II to complex III. Hepatocyte outcome might be mediated by cytokine1. In a
ischemia described in chronic liver pathology, pregnant and non-pregnant HEV infected women
enhances O 2 •− production by impairing function study, HEV viral load in acute viral hepatitis and

of complex III. TNF-α as one of the cytokines fulminant hepatic failure were comparatively higher
[59]
released from endotoxin-stimulated KC, through levels of TNF-α, IL-6, IFN-γ and TGF-β1 than those
intracellular signaling, leads to decreased function in controls; moreover TNF-α, IL-6 and IFN-γ had
of complex III. [60] Endotoxemia has been described significant positive correlation with viral load, serum
in chronic hepatitis. Furthermore, activation of bilirubin and prothrombin time within infected
sinusoidal inflammatory cells such as lymphocytes women. [68]
and KC has been described in chronic hepatitis C
virus infection. Therefore, ROS serve as signaling Cytokines and hepatic schistosoma infection
[61]
molecules for the initiation and perpetuation of the (Schistosomiasis)
inflammatory process that occurs with conditions Schistosomiasis is a chronic and debilitating disease
[69]
of oxidative stress. This involves genetic regulation. that affects over 200 million people worldwide.
Transcription factors that are directly influenced by The pathology, resulting from infection with the
reactive species and proinflammmatory signaling helminth parasite Schistosoma mansoni or Schistosoma
include NF-kB. NF-kB plays a central role in regulating japonicum, is predominantly caused by the host
genetic transcription and encoding of inflammatory immune response to parasite eggs that are laid
cytokines, growth factors, acute phase proteins, in the portal venous system and then become
adhesion molecules, other transcription factors, and trapped in hepatic sinusoids and sequestered
[70]
cell death regulators. These NF-kB regulated genes within granulomatous lesions. Cytokines, which
are important in regulating genetic activity during communicate between the fibrotic areas and the
critical illness, inflammatory diseases, and cancer. [62] immune system, form a network of host-parasite
responses. Nevertheless, the mechanisms involved in
Cytokines and hepatic hepatitis B virus infection the pathogenesis and progression of hepatic fibrosis
Hepatitis B, which is caused by hepatitis B virus in patients with schistosomiasis have not yet been
(HBV) infection, remains a major health threat fully elucidated. [71]
worldwide. Hepatic injury and regeneration from
chronic inflammation are the main driving factors of Studies on certain-cytokines knockout mice which
liver fibrosis and cirrhosis in chronic hepatitis B. [63] had been infected with Schistosoma mansoni showed
that egg granulomas and the hepatic fibrosis are
[72]
During HBV infection, intrahepatic production of dependent on the regulation of cytokines. Higher
Th1 inflammatory cytokines and type-I IFNs activates levels of eosinophil-derived cytokines were observed
two functionally independent pathways: an early in periportal fibrosis. A mixed cytokine pattern,
elimination of HBV nucleocapsid particles from characterized by positive correlation between TNF-α,
the hepatocytes; and a later post-transcriptional IL-4 and IL-5 was observed in periportal fibrosis.
downregulation of viral RNA. Most of these effects Also, the positive association between lymphocyte-
are mediated direct or indirectly by IFN-α, β and γ. derived IL-10 and the eosinophils cytokine profile
[64]
Additionally, chronic HBV patients who clear the virus was observed exclusively in intestine further
have higher levels of IL-12 than patients who remain emphasize the hypothesis that immunoregulatory
HBV positive. IL-12 can inhibit the replication of events take place controlling disease morbidity
[65]
[73]
HBV through the induction of IFN-γ. [66] in human schistosomiasis or in experimental
[74]
models. However, in human and animal
Cytokines and hepatitis E virus schistosomiasis, studies have shown that high levels
Hepatitis E virus (HEV) is a small non enveloped single- of TNF-α produced by peripheral blood mononuclear

Hepatoma Research | Volume 2 | June 1, 2016 137