EPIGENETICS

Explanations of how diabetes develops and progresses often involves two things: genes and environment. In other words, you may be born with a genetic disposition to diabetes that is then triggered by an environmental event or behavior. As it turns out, though, these factors aren’t always so separate. Scientists are finding that the environment can affect and even permanently modify genes themselves. How and why this happens is the subject of an emerging field of research called epigenetics. And the evidence suggests that diabetes may both cause epigenetic changes and be caused by them. It’s a classic of what came first, the chicken or the egg.

The prefix epi- means “on top of” or “in addition to”; epigenetics is the modification of the surface and message of a gene without altering the underlying DNA sequence. It’s something like making a proofreading mark on a document.

For people with diabetes, high or low blood glucose may trigger epigenetic changes. Some research suggests that these changes to genes may spur the development of diabetic complications, such as kidney damage and heart disease. Even a brief exposure to high blood glucose may cause an epigenetic change that stays in your body. This is called hyperglycemic memory, and it may explain why some people with diabetes get complications in spite of having good blood glucose control on average.

The development of both type 1 and type 2 diabetes is known to be influenced by the environment. Researchers are looking into what types of environmental factors, from nutrients and toxins to behavior and lifestyle, can trigger these epigenetic changes that raise or lower diabetes risk.

Scientists suspect that a mother’s nutrition while pregnant or a child’s diet during early life may even cause epigenetic changes that persist into adulthood. For the diabetes population, this is important because the pancreas’s insulin-producing beta cells replicate very early in life and then stop. “So a cell with epigenetic changes [from early life] just stays there.” And if epigenetic changes are transferred between cells through replication, then these changes in early life may have an even greater effect since they will be passed from the mother cell to the daughter cell throughout growth.

Epigenetics is a young field and a challenging one. Just identifying epigenetic changes to genes is difficult, a bit like trying to find a single out-of-place word in a long novel. Even so, researchers may someday discover through the study of epigenetics that the key to diabetes resides at the intersection of where genes and the environment meet.