Liver glycogen accumulation is associated with liver fat accumulation in type 1 diabetes

What is it about?

Glycogen is a storage form of glucose that is deposited in liver and in muscle in healthy people, but can occur in excess in disease states. Glycogenic hepatopathy is diagnosed clinically based on the combination of poorly controlled type 1 diabetes, an enlarged liver, elevated markers of liver damage and elevated lactate. Ultrasound is often used in such settings, but is poorly discriminative between liver fat accumulation and liver glycogen accumulation, and patients often have risks for both conditions. The histological features of glycogenic hepatopathy are subtle and are easily interpreted as normal. This study used an imaging technique called proton nuclear magnetic resonance spectroscopy (1H-NMRS) to examine liver fat and glycogen content in five clinical groups defined based on metabolic and liver disease phenotypes, including a group with type 1 diabetes and glycogenic hepatopathy. The main finding is that whilst type 1 diabetes isn’t associated with liver fat accumulation compared with controls, and when complicated by glycogenic hepatopathy, there is increased liver fat accumulation compared with controls. This is of clinical relevance as hepatic steatosis may compound the already elevated cardiovascular risk in this cohort with poorly controlled type 1 diabetes.

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Why is it important?

This study raises the possibility that in some cases the driving pathogenesis of glycogenic hepatopathy is in not only accumulation of glycogen, but also accumulation of fat. Steatosis is a common finding in liver biopsies and is not on its own prognostic for deleterious clinical outcomes. Nonetheless these findings may give clues to the pathogenesis of this disorder, which is associated with very difficult to control type 1 diabetes, significant psychosocial consequences and significant health costs.