End of the line for β cells?

Research published in the Journal of Clinical Investigation this week from scientists at the University of Pittsburgh has cast doubt on the ability of adult […]

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Research published in the Journal of Clinical Investigation this week from scientists at the University of Pittsburgh has cast doubt on the ability of adult mice to produce new pancreatic β cells. These cells produce the body’s insulin – the hormone responsible for regulating carbohydrate and fat metabolism.

In humans, it is thought that β cells numbers increase in response to a greater demand for insulin, but whether this is a result of cell division, or differentiation from a currently unknown precursor cell (neogenesis), remains controversial.

This study traced the cell lineage of β cells in mice to track whether any neogenesis occurred, and at what point in the mouse’s life. To do this, the mice were genetically modified to express a green fluorescent protein in their insulin producing cells, and tomato fluorescent protein in all other cells. When non-β cells start to produce insulin for the first time, they briefly express both proteins, giving them a yellow fluorescence. This can be used to identify whether neogenesis is occurring at various stages of the mouse’s life, using fluorescence activated cell sorting (FACS), a laser based technique to count cells with a specific fluorescence. Neogenesis was only observed during embryonic development, with no evidence found in adult mice.

This has implications into finding new treatments for diabetes mellitus, where efforts are being made to find sources of alternative β cells after the body’s own are destroyed, or are not present in sufficient numbers. It is hoped that if the body’s own population of β cells could be increased by neogenesis, but this study adds to evidence that this may not be a viable treatment – at least not in mice.

About Rakesh Dodhia

Rakesh is a 3rd year Biomedical Scientist at Lady Margaret Hall.