OBJECTIVETo investigate the relationship of gut flora and gut-derived endotoxin with minimal hepatic encephalopathy (MHE).

METHODSPatients with hepatitis B virus-related liver cirrhosis (HBV-LC) were screened for MHE using the number connect test-A (NCT-A) and digital symbol test (DST) and divided into the following groups: HBV-LC with (+) MHE (n = 26) and HBV-liver cirrhosis without (-) MHE (n = 25); in addition, one healthy immediate family member of each patient in the HBV-LC + MHE group was enrolled as a control. Each participant provided fecal and blood samples. PCR amplification and 454 pyrosequencing were used to detect bacterial 16S rRNA in feces. Turbidimetric Limulus amebocyte lysate assay was used to detect level of endotoxin in serum. The significance of inter-group differences was assessed by one-way ANOVA or Student's t-test.

RESULTSThe three groups showed different distributions of gut flora. The differences in the microbial communities' members and distributions were related to disease or health status, but not to the patient's genetic makeup or diet. In particular, the HBV-LC + MHE patients showed significantly lower amounts of different bacterial species and abundance of these species than the other two (non-MHE) groups (P less than 0.05). The healthy control family members had a richer diversity of gut flora than their counterparts with HBV-LC + MHE (P less than 0.05). The HBV-LV + MHE patients also had higher serum levels of endotoxin.

CONCLUSIONDevelopment of minimal hepatic encephalopathy in patients with HBV-LC may be related to a gut flora disorder or higher levels of endotoxin in serum.