Carrying extra weight around your midsection is known to increase your risk of heart attacks, and a new study by University of Michigan Cardiovascular Center researchers may have figured out why this is so.
They discovered a link between belly fat, also known as visceral fat, inflammation and hardening of the arteries (atherosclerosis).
The discovery came while the team was studying obese mice that lack leptin, a hormone that plays a role in appetite and metabolism. When they transplanted fat cells from normal mice into the leptin-deficient mice, the fat transplants prevented obesity and produced leptin.
The fat transplants also became inflamed, and the researchers set out to discover what was causing the inflammation, and whether it was linked to atherosclerosis.
They then divided mice that had been developed to be high in cholesterol and have hardened arteries into three groups: two that received fat transplants from normal mice, and one control group.
Some of the mice received visceral fat transplants, while others received subcutaneous fat (the type found just under the skin).
The mice that received the visceral fat developed atherosclerosis at an accelerated rate, and had inflammation similar to that found in the leptin-deficient mice. Those that received subcutaneous fat had increased inflammation, but not atherosclerosis, while the control group had neither inflammation nor increased atherosclerosis.
The results suggest a strong link between belly fat, inflammation and hardening of the arteries.
The researchers found that treating the mice with pioglitazone, a diabetes drug, was able to calm the inflammation and stop the atherosclerosis.