Impaired Glucagon-Mediated Suppression of VLDL-Triglyceride Secretion in Individuals With Metabolic Dysfunction–Associated Fatty Liver Disease (MAFLD)
Sara Heebøll, Jeyanthini Risikesan, Steffen Ringgaard, Indumathi Kumarathas, Thomas Damgaard Sandahl, Henning Grønbæk, Esben Søndergaard, Søren Nielsen
Abstract
Individuals with metabolic dysfunction-associated fatty liver disease (MAFLD) have elevated plasma lipids as well as glucagon, although glucagon suppresses hepatic VLDL-triglyceride (TG) secretion. We hypothesize that the sensitivity to glucagon in hepatic lipid metabolism is impaired in MAFLD. We recruited 11 subjects with severe MAFLD (MAFLD+), 10 with mild MAFLD (MAFLD-), and 7 overweight control (CON) subjects. We performed a pancreatic clamp with a somatostatin analog (octreotide) to suppress endogenous hormone production, combined with infusion of low-dose glucagon (0.65 ng/kg/min, t = 0-270 min, LowGlucagon), followed by high-dose glucagon (1.5 ng/kg/min, t = 270-450 min, HighGlucagon). VLDL-TG and glucose tracers were used to evaluate VLDL-TG kinetics and endogenous glucose production (EGP). HighGlucagon suppressed VLDL-TG secretion compared with LowGlucagon. This suppression was markedly attenuated in MAFLD subjects compared with CON subjects (MAFLD+: 13% ± [SEM] 5%; MAFLD-: 10% ± 3%; CON: 36% ± 7%, P < 0.01), with no difference between MAFLD groups. VLDL-TG concentration and VLDL-TG oxidation rate increased between LowGlucagon and HighGlucagon in MAFLD+ subjects compared with CON subjects. EGP transiently increased during HighGlucagon without any difference between the three groups. Individuals with MAFLD have a reduced sensitivity to glucagon in the hepatic TG metabolism, which could contribute to the dyslipidemia seen in MAFLD patients. ClinicalTrials.gov: NCT04042142.