Vasomotor hyper-responsiveness in SCD

Triggering factors of vaso-occlusion such as cold or stress are well known by physicians who care for patients with sickle cell disease (SCD). Surprisingly, however, the underlying pathophysiology has remained rather elusive so far. In this issue of Blood, Veluswamy et al have identified that thermal stimuli (both heat and cold) as well as pain and anxiety result in microvascular constriction in patients with SCD.(1) Importantly, they show that, unlike in healthy people, repeated stimuli in patients with SCD result in progressively increasing vasoconstriction, thereby setting the stage for vaso-occlusion, the central pathophysiological lesions associated with SCD.