Heart disease is the #1 cause of death in the world. Even so, numerous people with cardiovascular disease have none of the common risk factors such as smoking, obesity and high cholesterol. Researchers have now discovered a new link between gum disease and heart disease that may help find ways to save lives.
In recent years chronic infections have been associated with a disease that causes “furring” of the arteries, called atherosclerosis, which is the main cause of heart attacks. “A number of theories have been put forward to explain the link between oral infection and heart disease,” said Professor Greg Seymour from the University of Otago Dunedin, New Zealand. “One of these is that certain proteins from bacteria initiate atherosclerosis and help it progress. We wanted to see if this is the case, so we looked at the role of heat shock proteins.”
Heat shock proteins are produced by bacteria, animals, and plants. They are produced after cells are exposed to different kinds of stress conditions, such as inflammation, toxins, starvation, oxygen, and water deprivation. They can work as chaperone molecules, stabilizing other proteins, helping to fold them and transport them across cell membranes. Some also bind to foreign antigens and present them to immune cells.
Because heat shock proteins are produced by humans as well as bacteria, the immune system may not be able to differentiate between those from the body and those from invading pathogens. This can lead the immune system to launch an attack on its own proteins. “When this happens, white blood cells can build up in the tissues of the arteries, causing atherosclerosis,” said Professor Seymour.
“We found white blood cells called T cells in the lesions of arteries in patients affected by atherosclerosis. These T cells were able to bind to host heat shock proteins as well as those from bacteria that cause gum disease. This suggests that the similarity between the proteins could be the link between oral infection and atherosclerosis,” said Professor Seymour.
This molecular mimicry means that when the immune system reacts to oral infection, it also attacks host proteins, causing arterial disease. Professor Seymour says, “This is a significant step towards a more complete understanding of heart disease and improving treatment and preventive therapies. An understanding of all the possible risk factors could help lower the risk of developing heart disease and lead to a significant change in disease burden.”
Adapted from materials provided by Society for General Microbiology.