Diabetes is well known for causing high blood sugar, but many people don’t realize that it can also seriously harm the heart.
One of the most common problems is that the heart becomes stiff and struggles to relax properly between beats. This is called diastolic dysfunction, and it is a major reason why people with diabetes are more likely to develop heart failure.
For years, doctors have only been able to manage the symptoms, but a new study suggests there might be a way to directly fix the underlying heart damage.
A team of researchers from New Zealand, Australia, and other countries have discovered that diabetic hearts are missing an important protein needed for energy use. Normally, the heart uses a process called glycophagy to break down glycogen, a form of stored sugar, into glucose, which powers the heart’s constant pumping.
In diabetes, this recycling process does not work properly. Without enough of the protein that drives glycophagy, called GABARAPL1, glycogen builds up inside heart cells. This buildup makes the heart stiff, preventing it from relaxing and filling with blood in between beats.
The researchers decided to see what would happen if they could replace this missing protein. They used a specially designed virus to deliver the GABARAPL1 gene directly into the hearts of diabetic mice. After treatment, the mice’s hearts started working more normally again.
The glycogen buildup went down, the energy cycle restarted, and the hearts were able to relax more effectively. Importantly, the therapy fixed the heart problem without changing the mice’s blood sugar levels or body weight. This means the treatment targeted the heart directly, rather than just controlling diabetes symptoms.
To take the experiment one step further, the scientists also tested the therapy on tiny human “hearts” grown from stem cells in the lab. These mini hearts mimic how real human hearts behave.
After receiving the same genetic treatment, the diabetic mini hearts showed big improvements in how they relaxed after each beat. This result is exciting because it suggests the therapy might also work in real human patients one day.
Associate Professor Kim Mellor from the University of Auckland, one of the lead researchers, explained that the heart needs enormous amounts of energy to keep beating, and in diabetes this energy supply chain breaks down.
By fixing the recycling system with gene therapy, they were able to reverse the damage. Professor Lea Delbridge from the University of Melbourne added that this is a completely new way of thinking about diabetic heart disease, because it treats the heart directly rather than just managing blood sugar.
The researchers believe this discovery could lead to a new type of treatment for diabetic heart disease, one that focuses on how the heart fills with blood.
Right now, there are very few medicines that can improve the heart’s ability to relax and fill. Most treatments focus on how strongly the heart contracts, but filling is just as important for healthy blood flow.
Interestingly, early evidence suggests the treatment might work especially well in female hearts, which seem to respond more strongly to changes in glycophagy. The team now plans to continue studying this difference and to explore how the therapy could be safely tested in human patients.
Overall, this research shows that by targeting energy recycling inside the heart, scientists may have found a way to reverse diabetic heart damage.
While much more work is needed before this could become a treatment for people, the findings give hope for a future where doctors can fix the heart directly, instead of only controlling the side effects of diabetes.
If you care about heart disease, please read studies about a big cause of heart failure, and common blood test could advance heart failure treatment.
For more health information, please see recent studies about a new way to repair human heart, and results showing drinking coffee may help reduce heart failure risk.
The study is published in Nature Cardiovascular Research.
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