M. Odenthal

Acute liver failure is associated with elevated liver stiffness and hepatic stellate cell activation

Acute liver failure (ALF) is associated with massive short‐term cell death, whereas chronic liver injury is accompanied by continuous cell death. Hepatic stellate cells (HSCs) contribute to tissue repair and liver fibrosis in chronic liver injury, although their role in ALF remains unexplained. Twenty‐nine patients (median age = 43 years, 17 females and 12 males) with ALF according to the Acute Liver Failure Study Group criteria were included. Upon the diagnosis of ALF and after 7 days, we determined liver stiffness (LS) with FibroScan, standard laboratory parameters, and serum levels of matrix metalloproteinase 1 (MMP‐1), MMP‐2, MMP‐9, tissue inhibitor of metalloproteinases 1 (TIMP‐1), TIMP‐2, hyaluronic acid, and markers of overall cell death (M65) and apoptosis (M30). Stellate cell activation and progenitor response were analyzed immunohistochemically in biopsy samples of 12 patients with α‐smooth muscle actin (α‐SMA), keratin‐17, and keratin‐19 staining, respectively. Cell death markers (M30 level = 2243 ± 559.6 U/L, M65 level = 3732 ± 839.9 U/L) and fibrosis markers (TIMP‐1 level = 629.9 ± 69.4 U/mL, MMP‐2 level = 264 ± 32.5 U/mL, hyaluronic acid level = 438.5 ± 69.3 μg/mL) were significantly increased in patients versus healthy controls. This was paralleled by collagen deposition, elevated α‐SMA expression, and higher LS (25.6 ± 3.0 kPa). ALF was associated with ductular progenitor proliferation. Conclusion: Our results demonstrate HSC activation and a progenitor response in ALF. Positive correlations between LS, the degree of liver cell damage, and the intensity of HSC activation suggest that fibrosis is a response to ALF in an attempt to repair damaged tissue. (Hepatology 2010)

Adiponectin inhibits steatotic CD95/Fas up-regulation by hepatocytes: therapeutic implications for hepatitis C.

BACKGROUND/AIMS Steatosis may trigger hepatocytes to up-regulate CD95/Fas thereby increasing susceptibility to apoptosis, inflammation and fibrosis. We investigated this concept and potential roles of adiponectin and its receptors (AdipoR1; AdipoR2) in chronically HCV-infected patients. METHODS In 98 HCV+ patients and 20 controls, sera were tested for HCV genotypes, FFAs, adiponectin and the M30 apoptosis indicator, and biopsies were evaluated for steatosis/inflammation/fibrosis, CD95/Fas (mRNA/protein), adiponectin (mRNA/protein), AdipoR1/-R2 (mRNA) and M30 (protein). We also questioned whether adiponectin protects HepG2 hepatoblastoma cells from FFA-triggered CD95/Fas up-regulation and apoptosis. RESULTS Patients [HCV clades 1 (78%), 2 (3%) and 3 (19%)] revealed increased FFA and adiponectin serum levels (p = .005). Hepatocyte CD95/Fas up-regulation correlated with steatosis, inflammation and fibrosis (p = .004). Advanced fibrosis correlated significantly (p = .05) with serum M30. Liver adiponectin correlated with steatosis (p = .016), CD95/Fas (p < .001) and inflammation/fibrosis. Hepatocyte AdipoR2 mRNA specifically correlated with serum adiponectin and steatosis (p = .003), while hepatocyte AdipoR1 mRNA dropped in pronounced fibrosis (p = .060). Finally, adiponectin protected HepG2 cells from FFA-triggered CD95/Fas expression and induction of apoptosis (p = .0396). CONCLUSIONS In chronic HCV infection, steatosis up-regulates hepatocyte CD95/Fas and thus increases apoptosis, which facilitates inflammation and fibrosis. The physiologic countermeasure of adiponectin up-regulation may offer clues for future therapeutic intervention.

Intrahepatic IL-8 producing Foxp3⁺CD4⁺ regulatory T cells and fibrogenesis in chronic hepatitis C.

BACKGROUND & AIMS Regulatory CD4(+) T cells (Tregs) are considered to affect outcomes of HCV infection, because they increase in number during chronic hepatitis C and can suppress T-cell functions. METHODS Using microarray analysis, in situ immunofluorescence, ELISA, and flowcytometry, we characterised functional differentiation and localisation of adaptive Tregs in patients with chronic hepatitis C. RESULTS We found substantial upregulation of IL-8 in Foxp3(+)CD4(+) Tregs from chronic hepatitis C. Activated GARP-positive IL-8(+) Tregs were particularly enriched in livers of patients with chronic hepatitis C in close proximity to areas of fibrosis and their numbers were correlated with the stage of fibrosis. Moreover, Tregs induced upregulation of profibrogenic markers TIMP1, MMP2, TGF-beta1, alpha-SMA, collagen, and CCL2 in primary human hepatic stellate cells (HSC). HSC activation, but not Treg suppressor function, was blocked by adding a neutralizing IL-8 antibody. CONCLUSIONS Our studies identified Foxp3(+)CD4(+) Tregs as an additional intrahepatic source of IL-8 in chronic hepatitis C acting on HSC. Thus, Foxp3(+)CD4(+) Tregs in chronic hepatitis C have acquired differentiation as regulators of fibrogenesis in addition to suppressing local immune responses.

[Liver biopsy in chronic hepatitis C. Histopathology, molecular diagnostic analysis, and implications for therapeutic management].

ZusammenfassungDie Leberbiopsie gilt als Goldstandard für die Ermittlung des Leberparenchymschadens bei chronischer Hepatitis C. Im Zusammenhang mit klinisch-anamnestischen und serologischen Daten ermöglicht sie Aussagen zur Prognose und lässt daher die Notwendigkeit einer antiviralen Therapie und ihre Erfolgsaussichten abschätzen. Beurteilt werden muss der Grad der entzündlichen Aktivität sowie das Stadium der bestehenden Fibrose, die anhand bewährter, detaillierter Scoring-Systeme festgelegt werden. Ferner ist es notwendig, auf Schädigungsmuster zu achten, die nicht zum typischen histomorphologischen Bild einer chronischen Hepatitis C passen, da bei der Häufigkeit dieser Infektion immer auch mit koinzidenten Erkrankungen zu rechnen ist. Hierzu zählen insbesondere nutritiv- und medikamentös-toxische Parenchymschäden, biliäre Erkrankungen und die genetische Hämochromatose. Für spezielle Fragestellungen und serologisch unklare Situationen besteht heute zusätzlich die Möglichkeit, auch direkt aus der paraffineingebetteten Leberbiopsie das Hepatitis-C-Virus mittels RT-PCR sicher nachzuweisen.AbstractHistological evaluation of liver biopsies is the gold standard for assessing the severity of liver disease in chronic hepatitis C. In conjunction with anamnestic and serological data, it provides critical information regarding prognosis and therapeutic consequences. Grading of the necroinflammatory activity and staging of the manifested fibrosis according to well-established scoring systems are the essential parameters of the histopathological report. The frequency of chronic hepatitis C necessitates awareness of coinciding liver damage by nutritional or drug toxicity, bile duct diseases, and hereditary hemochromatosis. Detection of hepatitis C virus (HCV) RNA directly from the formalin fixed, paraffin-embedded biopsy specimen is highly sensitive and offers help in cases of equivocal results of serological testing for HCV.

Diagnostik der “seronegativen” chronischen Hepatitis am Gewebe

ZusammenfassungDie Beurteilung der Leberbiopsie bei einer chronischen Hepatitis sollte eine Stellungnahme zur Ätiologie, zum Aktivitätsgrad und zum Stadium der Erkrankung einschließen. Die sog. “seronegative” chronische Hepatitis kann bestimmte Fälle von chronischer Hepatitis C, Infektionen mit anderen Viren wie EBV und CMV, Fälle von markernegativer autoimmuner Hepatitis, medikamenteninduzierter chronischer Hepatitis sowie bei jüngeren Patienten den Morbus Wilson umfassen. Zur Aufklärung derartiger Fälle sollten molekularbiologische Methoden sowie histochemische Färbungen (z. B. für Kupfer) eingesetzt werden und nach histologischen Merkmalen für autoimmune Hepatitis oder Medikamentenschaden gefahndet werden.AbstractThe evaluation of a liver biopsy in chronic hepatitis should make a statement on the etiology and report the degree of activity and stage of the disease. The category of so called seronegative chronic hepatitis may include cases of chronic hepatitis C or infection with other viruses such as the Epstein-Barr virus (EBV) and cytomegalovirus (CMV), cases of marker-negative autoimmune hepatitis as well as drug-induced injury and Wilsons disease in younger patients. In order to establish the diagnosis, sensitive techniques of molecular biology should be applied as well as copper staining by histochemistry. Exact and detailed histopathologic analysis can reveal certain features of autoimmune hepatitis or drug injury.