Even in earlier stages of fibrosis in individuals with NAFLD/metabolic-associated fatty liver disease (MAFLD), deficiencies in urea synthesis (in part caused by impaired liver-α-cell axis with glucagon resistance and impaired ureagenesis24), microglial activation, astrocyte swelling, and possibly even neurodegenerative changes and brain atrophy – all caused by elevated ammonia levels – have been reported.25 Here, GCG is linked to Brain atrophy.