Low blood zinc exacerbates minimal hepatic encephalopathy via altered functional brain activity

Minimal hepatic encephalopathy (MHE) is a neuropsychiatric syndrome that significantly affects quality of life. It is associated with neural activity changes, reflected by the amplitude of low-frequency fluctuation (ALFF) in resting-state functional magnetic resonance imaging (rs-fMRI). Zinc deficiency compromises cognition; however, its relationship with the neural activity changes in MHE remains unclear.

To investigate blood zinc variations in MHE and their associations with ALFF.

Blood zinc levels were compared in 150 patients with cirrhosis. Among them, 49 underwent rs-fMRI to evaluate associations between zinc levels and ALFF, after adjusting for confounders.

Blood zinc levels were significantly lower in patients with MHE than in those with no hepatic encephalopathy (4.63 vs. 5.06 mg/L; P = 0.022). MHE prevalence was higher in females than in males (35.2% vs. 19.0%; P = 0.025). ALFFs in the bilateral angular gyrus and precuneus were positively correlated with blood zinc levels, whereas those in the bilateral fusiform gyrus were negatively correlated (P < 0.05 and P < 0.05, respectively).

Low blood zinc levels in patients with MHE are associated with altered neural activity in the bilateral angular gyrus, precuneus, and bilateral fusiform gyrus, representing a neural basis for cognitive impairment in MHE.