Assay to detect inhibitory substances in serum of patients with acute liver failure.

Patients with acute liver failure accumulate toxic substances in the circulation which may impair recovery of hepatic function. The aim of this study was to test an in vitro assay to detect inhibitory substances in the serum of patients with acute liver failure. Human liver-derived HepG2 cells were incubated for 24h in 96 well plates (30,000 cells/well) with sera (10%) from 24 patients with acute liver failure due to paracetamol overdose or NANB hepatitis and 11 normal controls. DNA synthesis was determined from the incorporation of 3H-thymidine and cell viability by the metabolism of the tetrazolium dye MTS. HepG2 cells exposed to acute liver failure sera incorporated significantly less 3H-thymidine (median 30% of control, range 0.2-169%) than normal sera (100%, 76-133%, p=0.002). Cell viability was also reduced (75%, 33-112% vs 100%, 96-105%, p<0.001). There was no correlation between these values and patient outcome or levels of plasma TNF-alpha or serum interferon-gamma. The assay detected inhibitory substances in sera of patients with acute liver failure and could be used to monitor the use of liver support systems.