8-oxo-7,8-dihydro-guanosine-urine levels are elevated in patients with liver cirrhosis and hepatic encephalopathy

Background Hepatic encephalopathy (HE) is a frequent complication in liver cirrhosis and oxidative stress plays an important role in its pathogenesis. A self-amplifying cycle of astrocyte swelling and oxidative as well as nitrosative stress leads to the alteration of neuronal function and the clinical symptoms of HE. 8-oxo-7,8-dihydro-guanosine (8-OHG) is a marker for oxidative stress, that can be measured in urine.

Aim Evaluation of 8-OHG as a marker for oxidative stress in patients with liver cirrhosis and HE

Study design Until now 64 Patients were included: 34 with liver cirrhosis and HE, 2 with liver cirrhosis and no HE, 10 controls with no known liver disease, 12 patients with various tumor diseases and 6 patients with pneumonia and no liver disease.

Hepatic encephalopathy was assessed using a computer based testing battery (Wiener Testsystem, Schuhfried GmbH, Wien), that is well established at our clinic. Furthermore the critical flicker frequency (CFF) of all patients was measured using the Hepatonorm analyzer (nevoLAB®, Meyerhöfen). From all patients with liver cirrhosis blood and urine samples were taken and analyzed. Blood-ammonia levels were measured in the routine diagnostics in the central laboratory of the university hospital Düsseldorf. 8-OHG-levels were measured in urine by mass spectroscopy.

Results Patients with liver cirrhosis and HE have statistically significant higher levels of 8-OHG in urine then patients with liver cirrhosis and no HE or controls without liver disease (3,55 µmol/mol creatinine vs. 2,16 µmol/mol creatinine vs. 2,20 µmol/mol creatinine). The levels of 8-OHG in patients with liver cirrhosis and HE were comparable with the levels in tumor patients or patients with pneumonia. Furthermore we identified a trend towards a negative correlation between 8-OHG levels and CFF. In addition our data show a significant negative correlation between 8-OHG and the serum levels of the antioxidant uric acid.

Discussion Our data indicate that 8-OHG is a marker for hepatic encephalopathy in patients with liver cirrhosis. Moreover higher levels of 8-OHG seems to be connected to more severe episodes of HE. Further experiments will investigate a potential decrease of 8-OHG levels in patients recovering from an episode of HE.

Supported by DFG through SFB 974.

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Artikel online veröffentlicht:
04. Januar 2021