Cerebral vasoreactivity in children and adolescents with type 1 diabetes mellitus

It is well established in clinical and experimental settings that diabetes mellitus, especially if long lasting, impairs autoregulation of cerebral blood flow (CBF). However, the onset and the course of development of this dysfunction remain unknown. We hypothesized that assessment of autoregulatory functions of cerebral arteries in children with relatively short duration of type 1 diabetes mellitus may provide an insight into the pathophysiology of the development of impaired autoregulation of CBF. Such a dysfunction of vasodilation of cerebral arteries can be assessed by transcranial Doppler. Therefore, to examine whether and when autoregulation of CBF becomes affected by diabetes, we used transcranial Doppler and a pCO(2) challenge in 17 males between the ages of 12-20 years with type I diabetes mellitus of 0.2-16 years duration and with varying degrees of glucose control. The results were compared with age-matched, healthy, nondiabetic controls. The CO2 challenge increased cerebral blood-flow velocities and decreased the pulsatility index. These changes were not influenced by the presence or duration of diabetes, insulin dose, or degree of diabetic control.