Earlier this week, first year PhD student Julie Faitg talked to us about her research project that uses electron microscopy to study mitochondria in skeletal muscle. Here she tells us more about this powerful technique.

Mitochondria are dynamic organelles. Until very recently, they were considered small, bean-shaped structures but we now know that they constantly move and undergo changes in their shape. For example, two mitochondria can encounter each other and decide to fuse together to become one. Alternatively, they can decide to separate from each other by fission.

Mitochondrial diseases encompass a variety of different symptoms related to mitochondrial dysfunction and impaired energy production. Recent studies have shown that mitochondrial dysfunction is associated with changes in mitochondrial shape affecting mitochondrial function and vice versa.

To be able to see the structure of mitochondria within cells, electron microscopy remains a powerful tool for obtaining high magnification images (examples of which are shown above). It is possible to look at the mitochondria in two dimensions (2D) or even in three dimensions (3D). This allows us to characterise mitochondrial shape and to map their organisation within cells, as shown in the video below.

It has so far not been possible to see which cells have dysfunctional mitochondria in skeletal muscle from mitochondrial disease patients using the 3D electron microscope.

For this reason, my PhD project will develop a means to detect the function of mitochondria as well as their shape with the 3D electron microscope. This method will help to improve the understanding of the disease and how mitochondrial damage spreads through the muscle cells.