Acute Local Ischemic Preconditioning in Patients With Type 1 Diabetes in Vivo

All patients will be studied in supine position after an overnight fast, while plasma glucose levels are monitored. In the first 8 patients intravenous insulin is administered as needed, to reach target glucose levels between 5-7 mmol/l. Patients will be subjected to 10 minutes of forearm ischemia (non-dominant arm), combined with handgripping at 50% of maximal force until exhaustion. Upon reperfusion, Tc-99m-HYNIC-Annexin A5 will be injected intravenously. Targeting of annexin A5 to thenar muscle and forearm flexor muscle will be quantified as the percentage difference in radioactivity between experimental and control side. This procedure will be performed twice (randomized cross-over design), with at least 2 week interval, either with or without 10 minutes ischemia followed by 10 minutes of reperfusion prior to ischemic exercise.

Depending on the results of this study, substudies will be performed to study the effect of diazoxide (K-ATP channel opener, may mimic ischemic preconditioning), glibenclamide (K-ATP channel blocker, may inhibit ischemic preconditioning) or adenosine (infusion into brachial artery of non-dominant arm as a substitute for ischemic preconditioning).