View clinical trials related to Cerebrovascular Function.
Filter by:Oral supplements containing exogenous ketones have recently become available and represent a novel tool for increasing plasma ketone bodies without the need for dietary restriction. Early evidence suggests that oral ketone supplements may enhance cerebral blood flow (CBF). However, a higher dose of a ketone monoester has been shown to slightly lower blood pH and reduce end-tidal CO2 (PetCO2) due to compensatory hyperventilation, which is accompanied by parallel reductions in CBF. Whether reductions in PetCO2 causes reductions in CBF is currently unknown. The purpose of this study is to investigate the effect of manipulating PetCO2 at normocapnia (PetCO2 maintained at baseline) or poikilocapnia (no PetCO2 targeting; breathing room air), following the ingestion of a dose of a ketone monoester on CBF and cerebrovascular reactivity to CO2 in young adults.
Ketone bodies are produced by the liver during periods of food scarcity or severe carbohydrate restriction. Blood ketones are an alternative fuel source used by the brain, heart, and skeletal muscle during periods of fasting. Further, ketones bodies act as a signalling molecule that have pleiotropic effects that upregulate cellular stress-resistance pathways throughout the body. Oral supplements containing exogenous ketones have recently become available and represent a novel tool for increasing plasma ketone bodies without the need for dietary restriction. Early evidence suggests that oral ketone supplements may enhance cerebral blood flow and improve cognition. However, the dose-dependent effects of a single ketone supplement on cerebral blood flow and cognition in young adults is currently unknown. The purpose of this study is to characterize the effects of ingesting a high versus low dose of an oral ketone monoester on cerebral blood flow, circulating blood markers, and cognition in young adults. As an exploratory aim, this study will investigate how oxygen uptake kinetics during submaximal exercise are impacted 2 hours after ingestion of a ketone supplement. Recent findings indicate that ketone supplementation may impair exercise performance due to the physiological stress (i.e., pH disturbances) imposed by an acute ketone dose. Delaying exercise onset by 2 hours after ingestion of a ketone supplement may enhance oxygen kinetics in a dose-dependent manner.
People who report subjective memory complaints have a greater risk of developing dementia. Memory issues may be an early warning sign of dysfunctional cerebral glucose metabolism and cerebral blood flow. Interventions that can restore cerebral metabolism and enhance cerebral blood flow may protect against conversion to dementia. Exogenous ketone supplements have been shown rapidly improves brain network function in young adults. Further, infusion studies demonstrate that ketone bodies enhance cerebral blood flow in cognitively normal adults. Whether acute ketone monoester supplementation can improve brain function in adults with subjective memory complaints is currently unknown. This study will investigate the effects of a single ketone monoester dose on resting-state functional connectivity in the default mode network and resting cerebral blood flow in adults with subjective memory complaints.