Diabetes has a long list of run-on health effects, and one of them is an increased risk of cardiovascular disease. Now, scientists at Oxford have uncovered a mechanism behind that, finding high blood sugar levels “reprogram” stem cells so the white blood cells they produce become inflammatory, creating more plaques that build up in blood vessels.
According to the CDC, diabetes doubles a person’s risk of developing heart disease or a stroke, and makes it more likely to strike at a younger age. It is thought that high blood sugar levels over an extended period of time can damage blood vessels and nerves, leading to the increased risk, but strangely that risk remains elevated even after a person gets their glucose levels under control.
In the new study, the Oxford team may have identified why that’s the case. The researchers found that high blood glucose may alter stem cells in bone marrow, which produce immune cells called macrophages. The altered stem cells end up producing macrophages that are more inflammatory, and go on to increase the buildup of plaques in arteries. These in turn restrict blood flow and can eventually lead to heart attacks.
In lab experiments, the team extracted white blood cells from samples taken from eight people with type 2 diabetes, and compared them to 16 people without the disease. All of the cells were grown in a solution with regular glucose levels, but those from the diabetic patients continued to show increased inflammatory responses compared to the controls.
Next, the researchers looked further upstream to find out why this was the case. In tests in mice, the team extracted bone marrow stem cells from nine mice that had diabetes and six mice that didn’t, then transplanted them into mice that had normal glucose levels.
And sure enough, the mice that received stem cells from diabetic mice had more inflammatory macrophages. They also went on to develop almost twice the amount of plaques in their blood vessels compared to mice that received transplants from non-diabetic donors.
The team says that this new finding could open up more treatment options for people with diabetes, especially those that target health complications that often fly under the radar.
“Our study is the first to show that diabetes causes long-term changes to the immune system, and how this might account for the sustained increase in the risk of heart attack,” says Robin Choudhury, lead researcher on the study. “We need to change the way we think about, and treat, diabetes. By focussing too narrowly on a managing a person’s blood sugar levels we’re only addressing part of the problem. Right now, people with diabetes aren’t receiving effective treatment for their increased risk of heart and circulatory disease. These findings identify new opportunities for preventing and treating the complications of diabetes.”
The research was published in the journal Circulation.
Source: Oxford University
