Background: Individuals with Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) have both elevated triglyceride and glucagon levels, although glucagon suppresses the very-low-density lipoprotein-triglyceride (VLDL-TG) secretion in lean individuals. Therefore, we hypothesized that the glucagon-mediated suppression of VLDL-TG secretion is impaired in MAFLD, with greater impairment in individuals with steatohepatitis (MASH) than individuals with simple steatosis (MAFL) .
Methods: 28 participants were included in the study (seven overweight control subjects (CON) , patients with MAFL, and with MASH) . We performed a somatostatin-clamp with replacement doses of growth hormone, insulin (0.2 mU/kg/min) and glucagon to suppress endogenous hormone production. Participants were studied during low-dose glucagon infusion (0.65 ng/kg/min, t=0─270 min, LowG) followed by a high-dose glucagon infusion (1.5 ng/kg/min, t=270─450 min, HighG) . We used 14C-labeled VLDL-TG and 3H-labeled glucose tracers to evaluate VLDL-TG secretion and endogenous glucose production (EGP) .
Results: HighG suppressed VLDL-TG secretion compared to LowG in all groups, but with a greater reduction in VLDL-TG secretion in CON than in the MAFLD groups (CON 36% (±SD 19%) ; MAFL 10% (±SD 8%) ; MASH 13% (±SD 16%) , p<0.01) . Thus, the suppression was similarly mitigated in both MAFLD groups. This led to insignificant reductions in plasma VLDL-TG, TG and VLDL-TG oxidation rates in the CON group, in contrast to stable or increasing values in the MAFLD groups (CON vs. MAFLD delta-values, p<0.01, p=0.02 and p=0.04) , respectively) . EGP was similar in all groups throughout the LowG period and rose similarly when increasing glucagon infusion rate.
Conclusions: Patients with MAFLD, MAFL as well as MASH, have an impaired glucagon-mediated suppression of VLDL-TG secretion which is a probable contributing factor to the dyslipidemia and the increased cardiovascular risk observed in individuals with MAFLD. NCT04042142
S.Heebøll: None. J.R.Risikesan: None. H.Gronbaek: Other Relationship; ARLA, Research Support; AbbVie Inc., Intercept Pharmaceuticals, Inc., Speaker's Bureau; AstraZeneca, Novartis AG. E.Søndergaard: None. S.Nielsen: None.
Independent Research Fund Denmark (9039-00177B and -00278B) and Aase og Ejnar Danielsens Fond