Gut microbiota: a new player in the pathogenesis of perioperative neurocognitive disorder?

Abstract

Perioperative neurocognitive disorder (PND), including postoperative delirium and postoperative cognitive dysfunction (POCD), is a common postoperative complication in elderly patients, who represent an expanding segment of our population. PND is a multifactorial disease resulting in higher morbidity and mortality. The precise mechanism of PND is yet to be fully delineated. Identifying the modifiable risk factors and mechanisms for PND would be an important step forward in preventing such adverse events and thus improving patients' outcomes. It is increasingly recognized that gut microbiota also manifest effects in the central nervous system via the microbiota‐gut‐brain axis, which has emerged as an important player in shaping aspects of behavior and cognitive function. Recent studies have found that patients with cognitive dysfunction after surgery and anesthesia have obvious gut microbiome disorders. These findings are paralleled by a growing body of preclinical investigations aimed at better understanding how surgery and anesthesia affect the central nervous system and possibly contribute to cognitive decline. Here, we present a broad topical review of the literature supporting the role of gut microbiota in PND. We provide an overview of the mechanisms underlying the pathogenesis of PND from pre‐clinical and human studies. Therefore, gut microbiota could be a putative therapeutic target for PND in the future.

Peripheral inflammation as a potential mechanism and preventive strategy for perioperative neurocognitive disorder under general anesthesia and surgery

“…The gut microbiota is a key component of the gut-brain axis. The association between disturbed gut microbiota and PND is currently a hot topic in research ( Dong et al, 2021 ). The gut microbiota is a collection of microorganisms, including bacteria, fungi, viruses, and others, living in the human gut and having a symbiotic relationship with the host, playing an important role in human health and disease development ( Chen et al, 2021 ).…”

Neurodegenerative and Neurodevelopmental Diseases and the Gut-Brain Axis: The Potential of Therapeutic Targeting of the Microbiome

“…A review of nine publications addressing microbiome changes with POCD incidence in animal models indicated significant changes in the microbiome in POCD mice after anaesthetic and surgery [338], with reductions in Firmicutes and increases in Proteobacteria [339]. In addition, there is evidence of the link between POCD and AD, with an increase in amyloid-β and hyperphosphorylated tau in animal models and patients with POCD [340]. One of the few human studies showed that elderly patients with POCD had reduced microbiome diversity with increased Anaerofilum (a genus common in depression) and decreased Fusicatenibacter, Coprococcus, and Dorea, among others [341].…”

“…One of the few human studies showed that elderly patients with POCD had reduced microbiome diversity with increased Anaerofilum (a genus common in depression) and decreased Fusicatenibacter, Coprococcus, and Dorea, among others [341]. While the change in microbiome structure in POCD is due to the stress of the procedure, combined with perioperative antibiotics and opioids and restricted nutrition, it is postulated that this dysbiosis, acting on the BBB, might contribute to POCD [340].…”