Type 2 Diabetes Is Physically Reshaping Your Heart—Here's What Scientists Just Discovered

Type 2 diabetes physically changes the structure of your heart, disrupting how it produces energy and making it stiffer over time. Researchers at the University of Sydney examined donated human heart tissue and found that diabetes actively reshapes heart muscle at the microscopic level, helping explain why people with diabetes face much higher rates of heart failure.

How Does Diabetes Actually Change Your Heart?

The study, published in EMBO Molecular Medicine, compared heart tissue from transplant recipients with healthy donor hearts. Dr. Benjamin Hunter and Associate Professor Sean Lal discovered that diabetes creates a unique molecular fingerprint inside heart cells, particularly in patients who also had ischemic heart disease—the leading cause of heart failure.

Using advanced microscopy techniques, the researchers could see direct structural damage to heart muscle. "We've long seen a correlation between heart disease and type 2 diabetes," said Dr. Hunter, "but this is the first research to jointly look at diabetes and ischemia heart disease and uncover a unique molecular profile in people with both conditions."

What Specific Changes Happen Inside the Heart?

Diabetes disrupts your heart in three major ways that researchers can now see and measure:

• Energy Production Problems: Diabetes reduces how sensitive heart cells are to insulin, making it harder for the heart to use glucose for fuel when it needs extra energy during heart failure
• Protein Damage: The proteins responsible for heart muscle contraction and calcium regulation are produced at lower levels, weakening the heart's pumping ability
• Fibrous Tissue Buildup: Excess scar-like tissue accumulates within the heart muscle, making it stiffer and less able to pump blood efficiently

In healthy hearts, energy comes mainly from fats, with glucose and ketones also contributing. But diabetes interferes with this process by reducing insulin sensitivity in the proteins that move glucose in and out of heart cells. "We observed that diabetes worsens the molecular characteristics of heart failure in patients with advanced heart disease and increases the stress on mitochondria—the powerhouse of the cell which produces energy," the researchers found.

Why Does This Matter for Treatment?

These findings help explain why more than 1.2 million Australians living with type 2 diabetes face such elevated heart disease risks. The research shows diabetes isn't just a risk factor—it's actively accelerating heart failure by interfering with essential biological processes.

"Now that we've linked diabetes and heart disease at the molecular level and observed how it changes energy production in the heart while also changing its structure, we can begin to explore new treatment avenues," said Associate Professor Lal. The identification of mitochondrial dysfunction and fibrosis-related pathways opens doors to new treatment approaches that could benefit millions of patients globally.

The researchers used ribonucleic acid (RNA) sequencing to confirm that many protein changes were also reflected at the gene level, particularly in pathways related to energy metabolism and tissue structure. This comprehensive approach—examining both the molecular and structural changes—provides the clearest picture yet of how diabetes physically reshapes the human heart.