Type 2 diabetes should no longer be viewed merely as a risk factor for heart disease. A team of researchers has shown that it directly damages the heart’s structure and energy systems, accelerating the progression to heart failure.
The study, published in EMBO Molecular Medicine and conducted by researchers at the University of Sydney—led by Dr. Benjamin Hunter and Associate Professor Sean Lal—reveals that diabetes alters how heart cells generate energy, weakens the muscle’s internal framework, and promotes the build-up of stiff, fibrous tissue; changes that severely impair the heart’s ability to pump blood.
By analysing donated human heart tissue from patients undergoing heart transplants and comparing it with tissue from healthy donors, the researchers provided rare and direct evidence of how diabetes reshapes the human heart at a molecular and structural level.
Crucially, the damaging effects of diabetes were most severe in patients with ischemic cardiomyopathy, the most common cause of heart failure worldwide and increasingly prevalent in India due to rising rates of obesity, sedentary lifestyles, hypertension, and poorly controlled diabetes.
“We have long observed a strong association between type 2 diabetes and heart disease,” said Dr. Hunter. “What this study demonstrates in humans is that diabetes produces a distinct molecular profile in the heart, especially when it coexists with ischemic heart disease.”
Under normal conditions, the heart is an energy-intensive organ that primarily relies on fats for fuel while also using glucose and ketones. During heart failure, glucose uptake typically increases as a compensatory mechanism. However, diabetes disrupts this process by reducing insulin sensitivity in heart muscle cells, impairing the transport of glucose into cells and placing excessive strain on mitochondria—the cell’s energy-producing units.
The researchers found that diabetes worsens the metabolic stress already present in heart failure, pushing heart cells closer to exhaustion. This has major implications for Indian patients, where delayed diagnosis, suboptimal glycaemic control, and limited access to specialised cardiac care often mean that both diabetes and heart disease remain poorly managed until advanced stages.
Beyond metabolic dysfunction, the study revealed that diabetes alters the production of proteins responsible for heart muscle contraction and calcium handling, both essential for maintaining a strong and coordinated heartbeat. In patients with diabetes and ischemic heart disease, these proteins were significantly reduced. At the same time, excess fibrous tissue accumulated within the heart muscle, making it stiffer and less elastic.
Advanced genetic analysis showed that these changes were reflected at the level of gene expression, particularly in pathways linked to energy metabolism and tissue structure. High-resolution imaging confirmed visible damage to heart muscle architecture, reinforcing the conclusion that diabetes actively remodels the heart rather than simply accompanying heart disease.
Dr. Lal emphasised that diabetes should no longer be considered a passive co-morbidity. “Our findings show that diabetes directly accelerates heart failure by disrupting energy production and reshaping the heart’s structure,” he said.
While he had not reviewed the study, Dr. Narender Singh Jhajhria, Director Professor, Department of CTVS at the centrally-run RML Hospital in New Delhi, underscored that diabetes remains a “silent killer” with far-reaching consequences.
“Diabetes damages blood vessels across the body, including those supplying critical organs such as the eyes, nerves, kidneys, and the heart, among others. Because the damage progresses quietly, people often realise its impact only when serious complications set in,” he said. Dr. Jhajhria stressed that adopting a healthy lifestyle—balanced diet, regular physical activity, weight control, and routine screening—is essential to keep diabetes at bay and prevent long-term organ damage.
Dr. Amit Kumar Malik, Director of Interventional Cardiology & Electrophysiology at Medanta, Noida, said diabetes is widely recognised as a coronary artery disease (CAD) equivalent and one of the strongest risk factors for heart disease. “This is particularly relevant in South-East Asia, including India, where we see early-onset diabetes, premature coronary artery disease, higher mortality, and a lipid profile that differs from Western populations,” he noted.
Dr. Malik added that even though much of the emerging evidence, as highlighted in the study, comes from advanced molecular research, all major clinical guidelines continue to identify diabetes as a major and independent risk factor for CAD.
The health experts also called for tighter blood sugar control, earlier cardiovascular screening, and integrated treatment approaches—measures that could significantly reduce the growing burden of heart failure among India’s millions of people living with diabetes.
