A Sheffield University Alumni Relations publication, entitled “investigating how diabetes affects the brain and heart,” reported how the university - in conjunction with the Royal Hallamshire Hospital - have embarked upon a two year MRI-assisted study on how diabetes affects the circulatory and nervous systems.

The effects of diabetes on these systems has been independently observed by other imaging modalities. Echocardiography has frequently detected diastolic dysfunction in diabetic patients, the recognition of which began in earnest with the results published in 1991 of the ongoing longitudinal Framingham Heart Study (Galderisi et al., 1991). This diabetes-related diastolic dysfunction (which can result in ‘diabetic cardiomyopathy’) is thought to be caused by apoptosis and myocardial fibrosis (Frustaci, Kajstura, Chimenti et al., 2000), due to microvascular damage (Galderisi, 2006).

Many patients with more advanced stages of diastolic dysfunction choose to monitor their heart rate with pulse oximeters or portable ECG monitors, as heart rates are often deliberately controlled. This is because diastolic dysfunction is, by definition, a failure of the heart muscle to relax quickly enough for the left ventricle to fill adequately. By prolonging the duration of diastole, the left ventricle is given more time to fill (Zile & Brutsaert, 2002). For the same reason, tachycardia can be particularly dangerous for patients with diastolic heart failure, as it increases the myocardial oxygen demand and reduces coronary perfusion time, putting the patient at risk of myocardial damage due to ischaemia, or even a myocardial infarction (heart attack). This can occur even in patients without any coronary artery disease (Zile & Brutsaert, 2002).

Patients with more advanced stages of diastolic dysfunction are usually kept at a resting heart rate of 60-70bpm.

Similarly, MRI imaging has advanced our knowledge of the cognitive effects of long-standing diabetes (Brands et al., 2006).

The Sheffield study is one of the first to simultaneously study both circulatory and nervous systems, and will surely shed more light on the complex topic of diabetes and the importance of health monitoring for diabetics.

 

References

Brands, A., Kessels, R., Hoogma R., et al. (2006). Cognitive performance, psychological well-being, and brain magnetic resonance imaging in older patients with type 1 diabetes. Diabetes 55:1800–1806.

Frustaci, A., Kajstura, J., Chimenti, C. et al. (2000). Myocardial cell death in human diabetes. Circ Res, 87, pp. 1123–1132.

Galderisi, M., Anderson, K., Wilson, P., Levy, D. (1991). Echocardiographic evidence for the existence of a distinct diabetic cardiomyopathy (the Framingham Heart Study). Am J Cardiol, 68 (1991), pp. 85–89.

Galderisis, M. (2006). Diastolic Dysfunction and Diabetic Cardiomyopathy: Evaluation by Doppler Echocardiography. Journal of the American College of Cardiology. Vol 48(8), pp. 1548-1551.

Seaquist, E. (2010). The Final Frontier: How Does Diabetes Affect the Brain? Diabetes, Vol. 59(1). pp. 4-5.

Zile, M., Brutsaert, D. (2002). New Concepts in Diastolic Dysfunction and Diastolic Heart Failure: Part II. Circulation, Vol. 105, pp. 1503-1508.