Researchers from the University of Kentucky in Lexington developed a new approach to rapidly assess the levels of polyglucosan bodies (PGBs) in different tissues and biofluids. The new approach could be used to accurately determine PGB levels, which could be relevant both in research and the clinical setting for diseases such as Pompe disease that are characterized by the accumulation of PGBs.

Currently, there are limited options to assess PGB levels. These usually rely on enzymatic degradation assays and mass spectrometry. In the present study, a team of researchers led by Matthew S. Gentry, PhD, developed a novel sandwich enzyme-linked immunosorbent assay (ELISA) method to quantify the amount of both glycogen and PGBs.

“By utilizing the specificities of glycogen and PGB antibodies, we can specifically capture glycogen or PGBs and detect them utilizing a unique carbohydrate binding module,” they wrote in an abstract presented at the Experimental Biology meeting and published in The FASEB Journal.


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After establishing the specificities of the assays and the sensitivity of the sandwich ELISAs in comparison to other techniques, the researchers have shown that the ELISA is able to quantify the amount of PGB in the brain in mouse models of Pompe disease and Lafora disease, another type of glycogen storage disorder.

Pompe disease is caused by a homozygous mutation in the GAA gene, which encodes the acid alpha-glucosidase (GAA) enzyme. The mutation causes a deficiency or complete absence of the GAA enzyme, the role of which is to break down glycogen inside cells.

This results in the accumulation of glycogen or aberrant glycogen-like aggregates called PGBs in different tissues, leading to symptoms such as feeding problems, poor weight gain, muscle weakness, and floppiness.

Reference

Cantrell AR, Manauis E, Webb M, et al. Development of a novel ELISA for sensitive quantitation of glycogen and polyglucosan bodies. FASEB J. Published online May 13, 2022. doi:10.1096/fasebj.2022.36.S1.R2533