New discovery: How type 1 diabetes leads to damage after heart attack
A new discovery could help people living with type 1 diabetes who are vulnerable to major damage after having a heart attack. Researchers haven’t been sure why heart damage continues for patients with the autoimmune type of diabetes.
New targets for therapy?
Researchers at Joslin Diabetes Center found out what triggers the autoimmune response that destroys heart muscle from type 1 diabetes. They also say there may be a way to stop it, opening the door for new types of therapy.
Myra A. Lipes, M.D, investigator in the Section on Immunology at Joslin and principal investigator of a study published in the June 13 edition of the journal Science Translational Medicine explained in a press release, “The problem arises from autoimmunity, a condition that people with type 1 diabetes already have.”
Lipes and her team focused on type 1 diabetes because death from heart disease is 13 times more prevalent for people living with the disease, compared to the general population.
The good news is Dr. Lipes and her team discovered the trigger for the autoimmune response that attacks heart tissue when type 1 diabetics suffer heart attack. The hope is that they can develop antigen therapy to halt ongoing damage.
Researchers know diabetes damages blood vessels, putting patients at higher risk for heart attack, but until now they couldn’t understand why diabetics suffer more heart damage afterwards that people who don’t have diabetes.
Normally, damaged or injured tissue repairs itself because of inflammatory signals that start a cascade of events. But type 1 diabetes causes an inflammatory response that, rather than leading to healing, leads to damage, which is related to autoimmune dysfunction.
The researchers discovered type 1 diabetes causes the body’s immune cells to attack myosin, the main protein found in heart muscle, which increasingly damages the heart; similar to the way insulin producing cells in the pancreas are destroyed from the disease. They specifically found alpha-myosin is the culprit that triggers the attack.
The ongoing heart damage is called chronic cardiac autoimmunity that eventually leads to heart failure. In people without type 1 diabetes, the body turns the attack off.
The researchers were able to use blood tests to find cardiac autoantibodies in 15 out of 18 type 1 diabetics who had survived heart attack. They then used MRI to confirm inflammation in the heart in a patient who tested positive for the autoantibodies.
“With these laboratory and patient studies, we now have a roadmap for future research and a promising antigen target for developing future interventions to help people with type 1 diabetes following heart attack,” Dr. Lipes says. “Our findings also may have broader implications, possibly improving outcomes after heart attack in patients with other autoimmune disorders.”
Joslin Diabetes Center
June 1, 2012
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