AIM: To investigate characteristics and determinants of the glucose-insulin pump system in patients with T1DM with CGM with particular emphasis on the system level (i.e. glucose CCs). We will perform single mixed meal tolerance tests as well as 24-hour studies in T1DM patients and in healthy controls. We will apply mathematical modelling tools developed by us and will create virtual patients and virtual controls from this database to gain further insights into the alterations of the glucose-insulin pump system in patients.