Advanced glycation end products and the absence of premature atherosclerosis in glycogen storage disease Ia

Introducton: Despite their unfavourable cardiovascular risk profile, patients with glycogen storage disease type Ia (GSD Ia) do not develop premature atherosclerosis. We hypothesized that this paradox might be related to a decreased formation of advanced glycation end products (AGEs) resulting from lifetime low plasma glucose levels and decreased oxidative stress. Methods: In 8 GSD Ia patients (age 20-34 years) and 30 matched controls we measured carotid intima-media thickness (IMT), skin autofluorescence (AF; a non-invasive index for AGEs), and specific AGEs (pentosidine, N-(carboxymethyl)lysine (CML), N-(carboxyethyl)lysine (CEL)) and collagen linked fluorescence (CLF, measured at excitation/emission wavelength combinations of 328/378 and 370/440 nm) in skin samples. Results: Carotid IMT was significantly lower in GSD Ia patients. Skin AF did not differ between patients and controls. The skin samples showed higher CEL levels in the patient group (p=0.008), but similar levels of pentosidine, CML, and CLF. In the total group, skin AF correlated with CML (r=0.39, p=0.031), CLF 328/378 nm (r=0.53; p=0.002) and CLF 370/440 nm (r=0.60; p=0.001). In the control group, AF also correlated with the maximum carotid IMT (r=0.6; p=0.004). Conclusion: Although our data confirm that GSD Ia patients present with a reduced burden of atherosclerosis, this phenomenon cannot be explained by differences in AGE accumulation as measured in the skin.