Usefulness of circulating EPAC1 as biomarkers of therapeutic response to GLP-1 receptor agonists

Aims The response to Glucagon-like peptide-1 receptor agonists (GLP-1RAs) is highly varia-ble among patients. Thus, the identification of predictive biomarkers of therapeutic response to GLP-1 RA could help us to optimize the use of this class of drugs. GLP-1RAs increase exchange proteins directly activated by cAMP (EPAC). The aim of the present study was to assess whether the increase of EPAC1 after GLP-1RAs treatment could be a biomarker of clinical response. Methods After showing that GLP-1 (10 ng/mL) significantly increased the expression of EPAC1 in human endo-thelial vascular cells (HUVEC), a pilot clinical study was planned. For this purpose 49 patients with type 2 diabetes who started treatment with liraglutide were included. EPAC1 concentration was determined by ELISA before and at one month of liraglutide treatment. Results We found that serum concentration of EPAC1 increased significantly after treatment with liraglutide. Only in those patients in whom EPAC1 increased (64%), a significant decrease in HbA1c, LDL-C, body mass index (BMI), and waist circumference was shown. Conclusions This pilot study suggests that the increase of circulating EPAC1 after GLP-1RAs treatment could be a useful biomarker to predict clinical GLP1-RAs response.