Glycaemic variability underlies myocyte dysfunction and myocardial injury risk in diabetes

Heart disease is the leading cause of morbidity and mortality in individuals with diabetes, due largely to risks associated with ischaemic injuries such as myocardial infarction (MI). We use human population genetic data to demonstrate that classical cardiovascular disease risk biomarkers, including common measures of hyperglycaemia, do not fully account for the increased risk of post-MI mortality in patients with diabetes. This study therefore systematically evaluates glycaemic stress underpinning cardiovascular risk in diabetes. Here, we show using in vivo studies in adult male mice and in vitro models that glycaemic variability, rather than sustained hyperglycaemia alone, is a key risk factor for cardiomyocyte dysfunction and increased susceptibility to myocardial injury in diabetes. We further demonstrate that patient plasma assays can elucidate the predictive potential of glycaemic variability as a primary contributor to cardiomyocyte dysfunction and subclinical cardiac injury in diabetes. These findings provide preclinical models for mechanistic and drug discovery studies and inform strategies for managing cardiovascular outcomes in patients with diabetes. Measures of hyperglycaemia are risk factors for cardiovascular disease. Here the authors report that glycaemic variability is also a driver of cardiac vulnerability in diabetes, integrating population genetics, clinical data and experimental models to show how glucose fluctuations worsen heart injury and cardiovascular risk.