Pompe disease is a rare, inherited muscle disorder caused by a decreased or complete failing activity of lysosomal acid alpha-glucosidase (GAA). This enzyme is responsible for breaking glycogen into glycose. Thus, Pompe disease leads to an accumulation of glycogen in tissue, especially in cardiac and skeletal muscles. Patients who suffer from Pompe disease struggle with muscle weakness, breathing difficulties, later leading to wheelchair dependency, among others. This clinical picture results in a need for further investigation of Pompe disease [1].

Myoblasts are a precursor form of muscle tissue and, therefore, are of special interest regarding the topic. Through Raman imaging it is possible to investigate myoblasts non-destructive, label-free, non-fixated, on a single-cell level. The cells are placed in a custom-designed closed measurement chamber, ensuring a stable environment and a constant nutrient supply during the measurement. Results of the Raman imaging are depicted in false color images showing the three components that are of highest interest: proteins (blue; mainly found in the nucleus), lipids (red, found in lysosomes surrounding the nucleus), and glycogen (green; found in accumulations in the cytoplasm). Our work shows two main findings: First, already myoblasts, as a very early form of cell culture, show high accumulations of glycogen in cells affected by Pompe disease compared to control cells; second, the accumulations of glycogen in cells affected by Pompe disease can not only be found in lysosomes, as expected but in large planar areas in the cytoplasm. These findings can lead to a deeper insight into Pompe disease on a single-cell level and can contribute to a broader understanding of the disease.