Circulating lipids and lipoproteins in glycogen storage disease type I with nocturnal intragastric feeding

With the advent of nocturnal intragastric feeding which protects against acute metabolic complications and promotes growth, patients with glycogen storage disease type I are attracting less attention. However, several biochemical alterations persist and suggest that the long-term risk of atherosclerotic heart disease remains high. Persisting hypertriglyceridemia and hypercholesterolemia were found in seven glycogen storage disease type I subjects, six of them following 5-6 yr of nocturnal intragastric feeding. When compared to ten age-matched controls, the patients showed significantly (P less than 0.001) higher low density lipoprotein cholesterol (LDL-C) (247.7 +/- 46.8 vs. 115.3 +/- 5.0 mg/dl) and lower high density lipoprotein cholesterol (HDL-C) (26.4 +/- 3.4 vs. 55.8 +/- 2.9 mg/dl). Triglyceride (TG) enrichment with cholesteryl ester depletion characterized the lipoprotein classes. The diameters of very low density lipoproteins (VLDL) and LDL were larger, while that of HDL was smaller and consistent with the predominance of the HDL3 subclass and a lower apoA-I/apoA-II ratio. The raised levels of TG appeared attributable not only to the well-described lipogenesis, but also to impaired catabolism of fat, as evidenced by the significantly (P less than 0.001) decreased activity of both peripheral lipoprotein lipase (3.17 +/- 0.43 vs. 14.15 +/- 0.50 mumol FFA.ml-1.hr-1) and hepatic lipase (1.88 +/- 0.30 vs. 4.83 +/- 0.90). This may well explain the high concentration of intermediate density lipoprotein (IDL) and the impaired conversion of HDL3 to HDL2. Low apoC-II/apoC-III1 could be related to defective lipoprotein lipase activity. These data suggest that glycogen storage disease type I patients on nocturnal intragastric feeding remain at risk for atherosclerosis and its complications.