Penumbra in Acute Ischemic Stroke

Acute ischemic stroke is one of the leading causes of disability and death worldwide. The brain tissue adjacent to the central necrotic core was first defined as ischemic penumbra characterized by reduced cerebral blood flow (CBF) with electrical failure but maintained ionic homeostasis and transmembrane electrical potential. Since then, the evolving concepts of the ischemic penumbra have been proposed based on energy metabolism, CBF thresholds, and protein synthesis, providing insight for the diagnosis and treatment of acute ischemic stroke. This paper summarizes the recent advances in the understanding of ischemic penumbra, from its discovery to the diagnosis methods based on imaging techniques and biomarkers, finally some of the treatments developed. In addition, we discussed future perspectives on therapeutic targets beyond the ischemic penumbra to develop a treatment for acute ischemic stroke.