Impaired Very‐Low‐Density Lipoprotein catabolism links hypoglycemia to hypertriglyceridemia in Glycogen Storage Disease type Ia

Joanne Hoogerland (1, 2) , Fabian Peeks (1, 2) , Brenda Hijmans (1, 2) , Justina Wolters (1, 2) , Sander Kooijman (3) , Trijnie Bos (1, 2) , Aycha Bleeker (1, 2) , Theo Dijk (1, 2) , Henk Wolters (1, 2) , Albert Gerding (1, 2) , Karen Eunen (1, 2) , Rick Havinga (1, 2) , Amanda Pronk (3) , Patrick Rensen (3) , Gilles Mithieux (4, 5, 6) , Fabienne Rajas (4, 5, 6) , Folkert Kuipers (1, 2) , Dirk‐jan Reijngoud (1, 2) , Terry Derks (1, 2) , Maaike Oosterveer (1, 2)

1 University of Groningen [Groningen]
2 UMCG - University Medical Center Groningen [Groningen]
3 LUMC - Leiden University Medical Center
4 NUDICE - Nutrition, diabète et cerveau
5 Université de Lyon
6 UCBL - Université Claude Bernard Lyon 1

Prevention of hypertriglyceridemia is one of the biomedical targets in Glycogen Storage Disease type Ia (GSD Ia) patients, yet it is unclear how hypoglycemia links to plasma triglyceride (TG) levels. We analyzed whole-body TG metabolism in normoglycemic (fed) and hypoglycemic (fasted) hepatocyte-specific glucose-6-phosphatase deficient (L-G6pc-/- ) mice. De novo fatty acid synthesis contributed substantially to hepatic TG accumulation in normoglycemic L-G6pc-/- mice. In hypoglycemic conditions, enhanced adipose tissue lipolysis was the main driver of liver steatosis, supported by elevated free fatty acid concentrations in GSD Ia mice and GSD Ia patients. Plasma very-low-density lipoprotein (VLDL) levels were increased in GSD Ia patients and in normoglycemic L-G6pc-/- mice, and further elevated in hypoglycemic L-G6pc-/- mice. VLDL-TG secretion rates were doubled in normo- and hypoglycemic L-G6pc-/- mice, while VLDL-TG catabolism was selectively inhibited in hypoglycemic L-G6pc-/- mice. In conclusion, fasting-induced hypoglycemia in L-G6pc-/- mice promotes adipose tissue lipolysis and arrests VLDL catabolism. This mechanism likely contributes to aggravated liver steatosis and dyslipidemia in GSD Ia patients with poor glycemic control and may explain clinical heterogeneity in hypertriglyceridemia between GSD Ia patients.

Keywords: Glycogen Storage Disease type Ia; hepatic steatosis; hypertriglyceridemia; metabolic control; translational research

Domains: Neurons and Cognition [q-bio.NC]

Joanne Hoogerland, Fabian Peeks, Brenda Hijmans, Justina Wolters, Sander Kooijman, et al.. Impaired Very‐Low‐Density Lipoprotein catabolism links hypoglycemia to hypertriglyceridemia in Glycogen Storage Disease type Ia. Journal of Inherited Metabolic Disease, 2021, Online ahead of print. ⟨10.1002/jimd.12380⟩. ⟨inserm-03257886⟩