A new study has revealed a new benefit of keeping sugar under control. Researchers at Tokyo Metropolitan University have shown that skeletal muscle satellite cells, key parts in muscle repair, proliferate better in low-glucose environments.
This is contrary to conventional wisdom that mammal cells do better when there is more sugar to feed their activities. Since ultra-low glucose environments do not allow the proliferation of other types of cells, the team could produce pure cultures of satellite cells, potentially a significant boost for biomedical research.
Healthy muscles are an important part of healthy living. With the wear and tear of daily use, our muscles continually repair themselves to keep them in top condition. In recent years, scientists have begun to understand how muscle repair works at the cellular level.
Skeletal muscle satellite cells have been found to be particularly important, a special type of stem cell that resides between the two layers of lining, the sarcolemma and the basal lamina, which surrounds myofiber cells in individual muscle fibers. When the myofiber cells are damaged, the satellite cells become active, multiplying and finally merging with the myofiber cells.
This not only helps to repair the damage, but also maintains muscle mass. To understand how we lose muscle due to disease, inactivity or age, understanding the specific mechanisms involved is a fundamental challenge for medical science.
A team of scientists from Tokyo Metropolitan University led by assistant professor Yasuro Furuichi, associate professor Yasuko Manabe and professor Nobuharu L Fujii have studied how skeletal muscle satellite cells multiply outside the body. Watching the cells multiply in Petri dishes in a growth medium, they noticed that higher glucose levels had an adverse effect on the growth rate. This is counterintuitive; glucose is considered essential for cell growth.
It is converted to ATP, the fuel that boosts a lot of cellular activity. Still, the team confirmed that the lower glucose media led to more cells, with all the expected biochemical markers for higher degrees of cell proliferation.
They also confirmed that this does not apply to all cells, something they were able to use to their advantage. In experiments on high-glucose media, satellite cell cultures always ended up mixing, simply because other types of cells in the original sample also multiplied.
By keeping glucose levels low, they were able to create a situation in which satellite cells could proliferate, but other cell types could not, giving a very pure culture of skeletal muscle satellite cells. This is a fundamental prerequisite for studying these cells in a variety of environments, including regenerative medicine.
So, was the amount of glucose in your original experiment somehow “right”? The team added glucose oxidase, a glucose-digesting enzyme, to reach even lower glucose levels, and made satellite cells grow in this low-glucose medium. Surprisingly, the cells appeared to do well and proliferated normally.
The conclusion is that these specific stem cells appear to derive their energy from a completely different source. Work is underway to try to define what this is.
The team noted that the sugar levels used in previous experiments corresponded to those found in diabetics. This may explain why muscle wasting is seen in diabetic patients and can have significant implications for how we can keep our muscles healthy longer.
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This story was published from a wire agency feed with no text changes. Only the title has been changed.