Brain derived neurotrophic factor in perioperative neurocognitive disorders: Current evidence and future directions.

An increase in the age of surgical patients as well as the volume of surgeries is associated with a rise in perioperative neurocognitive disorders. These disorders encompass acute delirium and longer-term cognitive dysfunctions. Brain derived neurotrophic factor (BDNF) is a neurotrophin that plays a dynamic role in a series of neurological functions including neuroplasticity, neurogenesis and synaptic regulation. Given the possible alterations to brain physiology in response to surgery, this review aims to explore the relationship between changes in central and peripheral BDNF concentrations and perioperative neurocognitive disorders. Higher levels of Brain tissue and blood BDNF have been associated with better cognitive function; however, the nature of the association between BDNF and delirium is uncertain. Preclinical models point to a significant depletion in BDNF expression and signalling within the brain post-operatively, while preliminary human studies demonstrate depletions in serum BDNF concentration after surgery. These findings suggest that the reduced BDNF concentrations may be associated with post-operative cognitive dysfunction. Thus, understanding the BDNF expression/signalling pathways may present a promising avenue for managing perioperative neurocognitive disorders symptoms. Nonetheless, given that results were primarily derived from preclinical models, it is critical for these findings to be validated in humans to confirm the relevance of this promising target.