Researchers uncover the chemical regulators that cause changes in heartbeat associated with diabetes.

One of the known complications of diabetes is an inability to regulate the heartbeat. Lack of heart rate control can lead to complications ranging from an intolerance for exercise to heart attacks. Approximately just under and slightly over 20% of patients with type 1 and 2 diabetes, respectively, suffer from this problem.

Receptors known as beta-adrenoceptors have previously been identified as partial regulators of the heartbeat in healthy people. Two different beta-adrenoceptors, ß1 and ß2, are involved.

Researchers at the University of Otago in New Zealand have found that the ß1-adrenoceptor is the primary regulator of changes in the heartbeats of patients with diabetes, while the ß2-adrenoceptor is not involved. The results, which were published in the journal Experimental Physiology, were observed in a rat model.

Specifically, a device to measure blood pressure and heartbeat and one to inject drugs that reduce heartbeat by targeting the beta-adrenoceptors were implanted into a rat model of diabetes. Using this approach, it was possible for the researchers to distinguish between the impacts of the ß1- and ß2- adrenoceptors.

They also reveal information about the physiochemical cause of poor heart rate regulation in patients with type 2 diabetes. Notably, treatment of diabetic patients with beta-blockers, which block hormones like adrenaline and are used to reduce heart rate and blood pressure in people that suffer from angina or high blood pressure, can be ineffective or in some cases lead to higher blood glucose levels. The results of the present study would indicate that beta-blockers targeting the ß1-adrenoceptor should be more effective.

If the results are confirmed in humans, the information may result in the development of more effective drugs for the treatment of heart problems in patients with diabetes. “This study provides novel insight into the pathological basis of heart rate dysregulation in type 2 diabetes. This could help us develop drugs to better address heart problems in diabetics,” said Regis Lamberts, corresponding author, and Senior Lecturer in the Department of Physiology - HeartOtago at the University of Otago.