Common misconceptions about cerebral blood flow

Cerebral blood flow (CBF) is the volume of blood delivered to brain tissue per unit time, usually expressed as millilitres per 100 grams of brain tissue per minute. It is not a single compound and has no sequence, formula or molecular weight; it is a physiological parameter, and the term is used interchangeably with cerebral perfusion in the clinical and imaging literature. Because CBF is a measurement rather than a substance, the misconceptions that surround it are misconceptions about what a given intervention has been shown to change, in which species, and by which method.

The work described below centres on the regulation of cerebral perfusion through vascular reactivity, endothelial and blood-brain barrier function, and the neurovascular and metabolic pathways that couple neural activity to local blood supply.

Research Studies

Avocado consumption and cerebral blood flow in pre-diabetic adults

A randomised crossover intervention is assessing the effect of 12 weeks of daily avocado consumption on cerebral blood flow and on markers of cardio- and vascular health in both the periphery and the brain. The population is pre-diabetic men and women with overweight or obesity, aged 40 to 75 years, with 34 participants enrolled. Secondary objectives include brain insulin sensitivity after intranasal insulin delivery, vascular function, metabolic markers, cognition and psychological well-being [1]. This is a registered protocol; it reports the design and the intended endpoints, not a completed result.

Citicoline and cerebral Doppler resistive index in neonatal hypoxic-ischemic encephalopathy

A trial is determining the efficacy of citicoline in improving cerebral blood flow parameters and neurological status in neonates with hypoxic-ischemic encephalopathy, using the Doppler resistive index and the Sarnat-Sarnat score after 72 hours of therapy [2]. The outcome measures here are Doppler-derived, which is worth noting: resistive index is an indirect index of downstream vascular resistance, not a direct flow measurement.

Nicotinamide riboside and cerebral blood flow in amnestic mild cognitive impairment

A 12-week double-blind, randomised, placebo-controlled pilot study evaluated the safety, tolerability and preliminary efficacy of the NAD⁺ precursor nicotinamide riboside for enhancing cognitive function and cerebral blood flow in adults with amnestic mild cognitive impairment. Forty-two participants completed the study (22 in the nicotinamide riboside group, 20 in the placebo group). Adherence was similar between groups and no serious adverse effects were reported. Blood NAD⁺ increased twofold in the supplemented group. There were no improvements in the cognitive outcomes reported [4]. The dissociation between the biochemical marker and the functional endpoint is the finding of interest.

Pterostilbene derivatives and cerebral ischemia-reperfusion injury in vitro and in vivo

Pterostilbene is a small molecule stilbenoid and a dimethyl analogue of resveratrol. Structural optimisation of pterostilbene produced a series of derivatives that were assessed for anti-ischemic activity both in vitro and in vivo, with ADMET prediction used to estimate drug-likeness. In vitro MTT cell viability analysis was conducted in neuroblastoma cells (SH-SY5Y) and brain microvascular endothelial cells [5]. The blood-brain barrier protection described for pterostilbene in cerebral ischemia-reperfusion injury is the context for this work; the derivative data are preclinical.

ACTH-like peptides and brain gene expression after experimental stroke in rats

Ischemic stroke results from a disruption of cerebral blood flow. Using RNA-Seq, differential expressed genes associated with the ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP peptides under cerebral ischemia were first identified at 4.5 hours after transient middle cerebral artery occlusion in the ipsilateral frontal cortex of rat brain. A subsequent analysis examined the penumbra-associated frontal cortex and the actions of the same peptides at 24 hours after occlusion [6]. This is a rat model of transient middle cerebral artery occlusion; the gene expression findings are animal-only.

Reactive oxygen species and cerebral blood flow regulation in healthy adults

A study enrolling 30 healthy participants (15 male, 15 female), aged 18 to 40 years, is testing the role of reactive oxygen species in regulating cerebral blood flow. Participants attend two study visits over a six-month period [7]. The design addresses a mechanistic question about CBF regulation in healthy adults rather than a disease population.

Dasatinib and quercetin and cerebral blood flow regulation in adults at risk of Alzheimer's disease

A pilot study is demonstrating the safety and feasibility of intermittent doses of dasatinib and quercetin in older adults at risk of Alzheimer's disease. The study evaluates whether the combination may improve cerebral blood flow regulation, mobility and cognition in this population, and whether it may prevent progression to Alzheimer's disease [8]. Safety and feasibility are the stated primary aims; any effect on CBF regulation is exploratory.

Comparison of the study designs above

Lifestyle and systemic contributors to cerebral perfusion

A scoping review examined the effect of the Mediterranean diet combined with physical activity on cognitive function in older adults, in a context where cognitive impairment and dementia are increasing and pharmacological treatments are limited, and where diet and physical activity are treated as modifiable preventive targets [9]. Separately, a multimodal neuroimaging study applied an integrated information decomposition framework to resting-state fMRI from 48 patients with heart failure, addressing the neural mechanisms of altered brain information processing in that population [10]. Both are reference points for the wider literature rather than direct CBF intervention trials.

If you are reading this for personal health reasons

The materials described on this page are supplied for laboratory research use only. We do not provide dosing information, medical guidance or recommendations for personal use of any compound. Anyone considering a compound for themselves should speak to a licensed clinician.

Sources

• [1] Long-term Effects of Avocado Consumption on Health in Pre-diabetic Individuals — ClinicalTrials.gov
• [2] Effect of Citicoline on Neurological Severity Score and Cerebral Doppler Resistive Index in Neonatal Hypoxic Ischemic Encephalopathy — ClinicalTrials.gov
• [3] Nutritional Intervention for Older Adults With Complete Dentures — ClinicalTrials.gov
• [4] A phase-II randomized controlled pilot study of nicotinamide riboside supplementation in older adults with amnestic mild cognitive impairment — Europe PMC
• [5] Structural Optimization of Pterostilbene, a Promising Lead Molecule, and Evaluation of Its Derivatives via ADMET Prediction and In Vitro/In Vivo Anti-Cerebral Ischemic Activity — Europe PMC
• [6] ACTH-like Peptides Compensate Rat Brain Gene Expression Profile Disrupted by Ischemia a Day After Experimental Stroke — Europe PMC
• [7] HYPEROXIA Responses and ROS — ClinicalTrials.gov
• [8] Safety and Feasibility of Dasatinib and Quercetin in Adults at Risk for Alzheimer's Disease — ClinicalTrials.gov
• [9] The effect of the Mediterranean diet combined with physical activity on cognitive function in older adults: a scoping review — Europe PMC
• [10] Mapping brain synergy dysfunction in heart failure patients with reduced and mildly reduced ejection fraction using multimodal neuroimaging: Functional and molecular insights — Europe PMC