From the Department of Medicine, Cardiovascular Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
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Background—Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted postprandially that promotes myocardial glucose uptake. The active amide GLP-1 (7-36) is degraded by the enzyme DPP-4, and drugs that inhibit this enzyme (such as sitagliptin) have been introduced to treat type 2 diabetes. We assessed the hypothesis that increasing the plasma concentration of GLP-1 by DPP-4 inhibition would protect the heart from ischemic left ventricular (LV) dysfunction during dobutamine stress echocardiography in patients with coronary artery disease.Methods and Results—Fourteen patients with coronary artery disease and preserved LV function awaiting revascularization were studied. After either a single dose of 100 mg sitagliptin or placebo, 75 g of glucose was given orally to promote GLP-1 secretion and dobutamine stress echocardiography was conducted with tissue Doppler imaging at rest, peak stress, and 30 minutes. After sitagliptin, plasma GLP-1 (7-36) was increased at peak stress (16.5±10.7 versus 9.7±8.7 pg/mL; P=0.003) and in recovery (12.4±5.5 versus 9.0±5.5 pg/mL; P=0.01), and the LV response to stress was enhanced (ejection fraction, 72.6±7.2 versus 63.9±7.9%, P=0.0001; mitral annular systolic velocity, 12.54±3.18 versus 11.49±2.52 cm/s; P=0.0006). DPP-4 inhibition also improved LV regional function in the 12 paired nonapical segments assessed by peak systolic tissue Doppler (velocity, 10.56±4.49 versus 9.81±4.26 cm/s, P=0.002; strain, −15.9±6.3 versus −14.6±6.6%, P=0.01; strain rate, −2.04±1.04 versus −1.75±0.98 s−1, P=0.0003). This was predominantly due to a cardioprotective effect on ischemic segments (velocity in ischemic segments, 9.77±4.18 versus 8.74±3.87, P=0.007; velocity in nonischemic segments, 11.51±4.70 versus 11.14±4.38, P=0.14). In recovery, sitagliptin attenuated the postischemic stunning seen after the control study.Conclusions—The augmentation of GLP-1 (7-36) by inhibition of DPP-4 improves global and regional LV performance in response to stress and mitigates postischemic stunning in humans with coronary artery disease.Clinical Trial Registration—URL: http://www.isrctn.org. Unique identifier: ISRCTN78649100.