Neurovascular unit on a chip: the relevance and maturity as an advanced in vitro model

The brain is a high-energy demanding organ,consuming around 20％of the metabolic energy generated.To fulfill this demand,cerebral blood flow(CBF)supplies oxygen and glucose continuously through the intricate network of cerebral blood vessels.Although for many years brain activity and blood flow were conceived as independent processes,MRI-based functional brain imaging demonstrated that there is a coupling between them,leading to the concept of the neurovascular unit(NVU)to reflect their interplay(Raichle and Mintun,2006).