Xi-Xian-Tong-Shuan capsule alleviates vascular cognitive impairment in chronic cerebral hypoperfusion rats by promoting white matter repair, reducing neuronal loss, and inhibiting the expression of pro-inflammatory factors.

BACKGROUND: While the number of cases of vascular cognitive impairment caused by chronic cerebral hypoperfusion (CCH) has been increasing every year, there are currently no clinically effective treatment methods. At present, Xi-Xian-Tong-Shuan capsule is predominantly used in patients with acute cerebral ischemia; however, its protective effect on CCH has rarely been reported. OBJECTIVE: To explore the underlying mechanisms by which Xi-Xian-Tong-Shuan capsule alleviates cognitive impairment caused by CCH. METHODS: A model of CCH was established in specific-pathogen-free (SPF)-grade male Sprague-Dawley (SD) rats using bilateral common carotid artery occlusion (BCCAO). Xi-Xian-Tong-Shuan capsules were intragastrically administered for 42 days after the BCCAO surgery. We then assessed for changes in cognitive function, expression levels of pro-inflammatory factors, and coagulation function as well as for the presence of white matter lesions and neuronal loss. One-way ANOVA and Tukey's test were used to analyze the experimental data. RESULTS: The rats showed significant cognitive dysfunction after the BCCAO surgery along with white matter lesions, a loss of neurons, and elevated levels of inflammatory factors, all of which were significantly reversed after intervention with Xi-Xian-Tong-Shuan capsules. CONCLUSION: Xi-Xian-Tong-Shuan capsules can ameliorate vascular cognitive impairment in CCH rats by preventing damage of white matter, reducing neuronal loss, and inhibiting the expression of pro-inflammatory factors. Our study provides a new reference for the clinical treatment of chronic cerebral ischemia with Xi-Xian-Tong-Shuan capsules.

Xiaoxuming Decoction Regulates Vascular Function by Modulating G Protein-Coupled Receptors: A Molecular Docking Study.

Xiaoxuming decoction (XXMD) is a traditional Chinese herbal medicine (CHM) that is used for the treatment of stroke in China. Stroke injury damages the cerebral vasculature and disrupts the autoregulation of vasoconstriction and vasodilatation, which is crucial for maintaining constant cerebral blood flow (CBF). It has been reported that XXMD exerts a positive effect on cerebral circulation in animal models of stroke. However, the mechanisms underlying the regulatory effect of XXMD on vascular tone, and the interactions among the multiple components of XXMD, remain unclear. In this study, XXMD was found to induce relaxation of the basilar artery rings of rats precontracted by 5-hydroxytryptamine (5-HT) in vitro, in a dose-dependent manner. The modulation of vascular tone and the process of cerebral ischemia are mediated via the interactions between G protein-coupled receptors (GPCRs) and their ligands, including 5-HT, angiotensin II (Ang II), and urotensin II (UII). Thus, the potential synergistic effects of the different components of XXMD on the regulation of vasoconstriction and vasodilation were further investigated by molecular docking based on network pharmacology. We constructed and analyzed a database comprising 963 compounds of XXMD and studied the interactions between five vascular GPCRs (5-HT1A receptor (5-HT1AR), 5-HT1B receptor (5-HT1BR), Ang II type 1 receptor (AT1R), beta 2-adrenergic receptor (ß2-AR), and UII receptor (UTR)) and the various herbal constituents of XXMD using molecular docking. By constructing and analyzing the compound-target networks of XXMD, we found that Glycyrrhizae Radix et Rhizoma, Ginseng Radix et Rhizoma, and Paeoniae Radix Alba were the three major herbs that contained a large number of compounds with high docking scores. We additionally observed that several constituents of XXMD, including gallotannin, liquiritin apioside, nariutin, 1,2,3,4,6-pentagalloylglucose, folic acid, and ginsenoside Rb1, targeted multiple vascular GPCRs. Moreover, the interactions between the components of XXMD and the targets related to vascular tone constituted the comprehensive cerebrovascular regulatory function of XXMD and provided a material basis of the vasoregulatory function of XXMD. The study reports the contributions of various components of XXMD to the regulatory effects on vascular tone and provides scientific evidence for the multicomponent and multitargeting characteristics of XXMD.

Pilot assessment of omega-3 fatty acids and potassium thiocyanate in sickle cell anemia patients with conditional peak systolic cerebral artery blood velocity.

OBJECTIVE: The purpose of this pilot study was to explore the effect of omega-3 fatty acids and potassium thiocyanate on conditional peak systolic cerebral artery blood velocity in children with sickle cell anemia (SCA). METHODS: Transcranial doppler ultrasonography (TCD) was done on 232 SCA children, and 21 found with conditional peak systolic blood velocity (PSV) of 200-249 cm/s in internal carotid, middle or anterior cerebral arteries. These were randomized to receive omega-3 fatty acids and potassium thiocyanate with standard treatment of SCA (test group, N = 14), or standard treatment only (control group, N = 7). After 3 months of treatment, PSV was measured again. RESULTS: Right middle cerebral artery PSV was significantly reduced in the test relative to the control groups (p = 0.04). PSV returned to normal in 79% of the test versus 43% of the control group; and increased to abnormal in one member of the control group, but none of the test group. CONCLUSIONS: The pilot data suggest that in SCA, omega-3 fatty acids and potassium thiocyanate might reduce conditional blood velocity to normal, or prevent progression to abnormal values. A larger, randomized, clinical trial is required to further address the current gap in management of conditional TCD blood velocity.

Phase 1 study to access safety, tolerability, pharmacokinetics, and pharmacodynamics of kynurenine in healthy volunteers.

The kynurenine pathway (KP) is the main path for tryptophan metabolism, and it represents a multitude of potential sites for drug discovery in neuroscience, including pain, stroke, and epilepsy. L-kynurenine (LKYN), the first active metabolite in the pathway, emerges to be a prodrug targeting glutamate receptors. The safety, tolerability, pharmacokinetics, and pharmacodynamics of LKYN in humans have not been previously investigated. In an open-label, single ascending dose study, six participants received an intravenous infusion of 50, 100, and 150 µg/kg LKYN and new six participants received an intravenous infusion of 0.3, 0.5, 1, and 5 mg/kg LKYN. To compare the pharmacological effects between species, we investigated in vivo the vascular effects of LKYN in rats. In humans, LKYN was safe and well-tolerated at all dose levels examined. After infusion, LKYN plasma concentration increased significantly over time 3.23 ± 1.12 µg/mL (after 50 µg/kg), 4.04 ± 1.1 µg/mL (after 100 µg/kg), and 5.25 ± 1.01 µg/mL (after 150 µg/kg) (p ≤ 0.001). We observed no vascular changes after infusion compared with baseline. In rats, LKYN had no effect on HR and MAP and caused no dilation of dural and pial arteries. This first-in-human study of LKYN showed that LKYN was safe and well-tolerated after intravenous infusion up to 5 mg/kg over 20 minutes. The lack of change in LKYN metabolites in plasma suggests a relatively slow metabolism of LKYN and no or little feed-back effect of LKYN on its synthesis. The therapeutic potential of LKYN in stroke and epilepsy should be explored in future studies in humans.

Effects of acetate on cerebral blood flow, systemic inflammation, and behavior in alcohol use disorder.

BACKGROUND: Alcohol use disorders (AUDs) are associated with altered regulation of physiological processes in the brain. Acetate, a metabolite of ethanol, has been implicated in several processes that are disrupted in AUDs including transcriptional regulation, metabolism, inflammation, and neurotransmission. To further understand the effects of acetate on brain function in AUDs, we investigated the effects of acetate on cerebral blood flow (CBF), systemic inflammatory cytokines, and behavior in AUD. METHODS: Sixteen participants with AUD were recruited from a nonmedical, clinically managed detoxification center. Each participant received acetate and placebo in a randomly assigned order of infusion and underwent 3T MR scanning using quantitative pseudo-continuous arterial spin labeling. Participants and the study team were blinded to the infusion. CBF values (ml/100 g/min) extracted from thalamus were compared between placebo and acetate using a mixed effect linear regression model accounting for infusion order. Voxel-wise CBF comparisons were set at threshold of p < 0.05 cluster-corrected for multiple comparisons, voxel-level p < 0.0001. Plasma cytokine levels and behavior were also assessed between infusions. RESULTS: Fifteen men and 1 woman were enrolled with Alcohol Use Disorders Identification Test (AUDIT) scores between 13 and 38 with a mean of 28.3 ± 9.1. Compared to placebo, acetate administration increased CBF in the thalamus bilaterally (Left: 51.2 vs. 68.8, p < 0.001; Right: 53.7 vs. 69.6, p = 0.001), as well as the cerebellum, brainstem, and cortex. Older age and higher AUDIT scores were associated with increases in acetate-induced thalamic blood flow. Cytokine levels and behavioral measures did not differ between placebo and acetate infusions. CONCLUSIONS: This pilot study in AUD suggests that during the first week of abstinence from alcohol, the brain's response to acetate differs by brain region and this response may be associated with the severity of alcohol dependence.

Dietary flavanols improve cerebral cortical oxygenation and cognition in healthy adults.

Cocoa flavanols protect humans against vascular disease, as evidenced by improvements in peripheral endothelial function, likely through nitric oxide signalling. Emerging evidence also suggests that flavanol-rich diets protect against cognitive aging, but mechanisms remain elusive. In a randomized double-blind within-subject acute study in healthy young adults, we link these two lines of research by showing, for the first time, that flavanol intake leads to faster and greater brain oxygenation responses to hypercapnia, as well as higher performance only when cognitive demand is high. Individual difference analyses further show that participants who benefit from flavanols intake during hypercapnia are also those who do so in the cognitive challenge. These data support the hypothesis that similar vascular mechanisms underlie both the peripheral and cerebral effects of flavanols. They further show the importance of studies combining physiological and graded cognitive challenges in young adults to investigate the actions of dietary flavanols on brain function.

Tuling Wendan Decoction combined with flunarizine in the treatment of migraine patients and the effect of intervention on serum cyclooxygenase-2, endothelin-1 and nitric oxide.

This experiment aimed to explore the curative effect of Tuling Wendan Decoction combined with flunarizine on migraine patients and the intervention effect on serum cyclooxygenase-2 (COX-2), endothelin-1 (ET-1), nitric oxide(NO) levels. For this purpose, from January 2019 to January 2020, 96 patients with migraine in our hospital were selected as the research object. Using a simple randomization method, patients who meet the criteria were assigned 1:1, and each patient was assigned a random number, of which the number 1 to 48 were the observation group, and the number 49 to 96 were the control group. The control group was treated with flunarizine, and the observation group was treated with Tuling Wendan Decoction combined with flunarizine. Comparing the efficacy, incidence of adverse reactions, the incidence of headache, cerebral blood flow rate [basal artery (BA), vertebral artery (VA), middle cerebral artery (MCA)], vascular endothelial function (serum COX-2, ET-1, NO levels), neurological function [5-hydroxytryptamine (5-HT), brain-derived neurotrophic factor (BDNF), calcitonin gene-related peptide (CGRP)] before treatment, 4 weeks and 8 weeks after treatment between the two groups. The results for efficacy showed that after 8 weeks of treatment, the total effective rate of the observation group (93.75%) was higher than that of the control group (77.08%, P<0.05). In regards to the situation of headache attack, the number of headache attacks, duration, pain degree and accompanying symptom scores of the observation group after 4 weeks and 8 weeks of treatment were lower than those of the control group (P<0.05). Results of cerebral blood flow velocity showed that the blood flow velocity of BA, VA, MCA in the observation group was lower than that in the control group after 4 and 8 weeks of treatment (P<0.05). Vascular endothelial function results indicated that the serum COX-2 and ET-1 levels of the observation group were lower than those of the control group after 4 weeks and 8 weeks of treatment, and the serum NO levels were higher than that of the control group (P<0.05). The serum BDNF and CGRP levels of the observation group were lower than those of the control group after 4 weeks and 8 weeks of treatment, and the serum 5-HT levels were higher than the control group (P<0.05). The incidence of adverse reactions between the two groups was not statistically significant (P>0.05). It was concluded that Tuling Wendan Decoction combined with flunarizine is the first treatment for migraine, with definite curative effect and can effectively improve the onset of headache, reduce the speed of cerebral blood flow, regulate vascular endothelial function and nerve function, and ensure safety.

A Randomized, Crossover Study of the Acute Cognitive and Cerebral Blood Flow Effects of Phenolic, Nitrate and Botanical Beverages in Young, Healthy Humans.

BACKGROUND: In whole foods, polyphenols exist alongside a wide array of other potentially bioactive phytochemicals. Yet, investigations of the effects of combinations of polyphenols with other phytochemicals are limited. OBJECTIVE: The current study investigated the effects of combining extracts of beetroot, ginseng and sage with phenolic-rich apple, blueberry and coffee berry extracts. DESIGN: This randomized, double-blind, placebo-controlled crossover design investigated three active beverages in 32 healthy adults aged 18-49 years. Each investigational beverage comprised extracts of beetroot, ginseng and sage. Each also contained a phenolic-rich extract derived from apple (containing 234 mg flavanols), blueberry (300 mg anthocyanins) or coffee berry (440 mg chlorogenic acid). Cognition, mood and CBF parameters were assessed at baseline and then again at 60, 180 and 360 min post-drink. RESULTS: Robust effects on mood and CBF were seen for the apple and coffee berry beverages, with increased subjective energetic arousal and hemodynamic responses being observed. Fewer effects were seen with the blueberry extract beverage. CONCLUSIONS: Either the combination of beetroot, ginseng and sage was enhanced by the synergistic addition of the apple and coffee berry extract (and to a lesser extent the blueberry extract) or the former two phenolic-rich extracts were capable of evincing the robust mood and CBF effects alone.

The nootropic and anticholinesterase activities of Clitoria ternatea Linn. root extract: Potential treatment for cognitive decline.

BACKGROUND: Clitoria ternatea (CT) is an herbal plant that has been used as a memory booster in folk medicine. CT root extract has been proven to restore chronic cerebral hypoperfusion (CCH)-induced memory deficits in a rat model, but the underlying mechanisms and the toxicity profile following repeated exposure have yet to be explored. THE AIM OF THE STUDY: To investigate the effects of the chronic (28 days) oral administration of CT root extract on CCH-induced cognitive impairment, neuronal damage and cholinergic deficit, and its toxicity profile in the CCH rat model. MATERIALS AND METHODS: The permanent bilateral occlusion of common carotid arteries (PBOCCA) surgery method was employed to develop a CCH model in male Sprague Dawley (SD) rats. Then, these rats were given oral administration of CT root extract at doses of 100, 200, and 300 mg/kg, respectively for 28 days and subjected to behavioural tests. At the end of the experiment, the brain was harvested for histological analysis and cholinesterase activities. Then, blood samples were collected and organs such as liver, kidney, lung, heart, and spleen were procured for toxicity assessment. RESULTS: Chronic treatment of CT root extract at doses of 200 and 300 mg/kg, restored memory impairments induced by CCH. CT root extract was also found to diminish CCH-induced neuronal damage in the CA1 region of the hippocampus. High dose (300 mg/kg) of the CT root extract was significantly inhibited the increased acetylcholinesterase (AChE) activity in the frontal cortex and hippocampus of the PBOCCA rats. In toxicity study, repeated doses of CT root extract were found to be safe in PBOCCA rats after 28 days of treatment. CONCLUSIONS: Our findings provided scientific evidence supporting the therapeutic potential of CT root extract in the treatment of vascular dementia (VaD)-related cholinergic abnormalities and subsequent cognitive decline.

Epimedium flavonoids protect neurons and synapses in the brain via activating NRG1/ErbB4 and BDNF/Fyn signaling pathways in a chronic cerebral hypoperfusion rat model.

Cerebral hypoperfusion is a common feature of cerebral small vascular disease (CSVD), which has been considered as one of the causes of cognitive decline in recent years. Epimedium flavonoids (EF) are the main ingredients extracted from Epimedium. The purpose of this study was to investigate the effects of EF on cognitive impairment, and the underlying mechanisms in rats with permanent occlusion of the bilateral common carotid artery (2VO). EF (50, 100, and 200 mg/kg) was intragastrically administered for 12 weeks starting 2 weeks after 2VO surgery. The results showed that EF treatment improved learning and memory impairment in 2VO rats evaluated by novel object recognition and Y-maze tests. NeuN immunohistochemical staining indicated that EF alleviated neuronal loss in the hippocampus and cerebral cortex of 2VO rats. MAP-2 immunofluorescence staining and western blotting showed that EF protected neuronal dendrites and increased the expression of cytoskeleton proteins MAP-2 and NF200 in the hippocampus of 2VO rats. Moreover, EF protected the synapse ultrastructure detected by transmission electron microscopy, and increased the expression of synaptic plasticity-related proteins, including synaptophysin, synaptotagmin-I, synapsin I, PSD-95, p-NMDA2B, and p-CaMKII-α in the hippocampus of 2VO rats. In addition, EF increased the expression of neuregulin-1 (NRG-1), p-ErbB4, brain-derived neurotrophic factor (BDNF), p-Fyn, PI3K, p-Akt, and p-CREB in the hippocampus of 2VO rats. These results suggest that EF may protect neurons and synapses by activating the NRG1/ErbB4, BDNF/Fyn, and P13 K/Akt/CREB pathways in the hippocampus and cerebral cortex, thus improving cognitive impairment induced by chronic cerebral hypoperfusion. EF may be a potential candidate drug for chronic cerebral hypoperfusion and CSVD therapy.

Effect and Safety of Hydroxysafflor Yellow A for Injection in Patients with Acute Ischemic Stroke of Blood Stasis Syndrome: A Phase II, Multicenter, Randomized, Double-Blind, Multiple-Dose, Active-Controlled Clinical Trial.

OBJECTIVE: To assess the effect and safety of Hydroxysafflor Yellow A for Injection (HSYAI) in treating patients with acute ischemic stroke (AIS) and blood stasis syndrome (BSS). METHODS: A multicenter, randomized, double-blind, multiple-dose, active-controlled phase II trial was conducted at 9 centers in China from July 2013 to September 2015. Patients with moderate or severe AIS and BSS were randomly assigned to low-, medium-, high-dose HSYAI groups (25, 50 and 70 mg/d HSYAI by intravenous infusion, respectively), and a control group (Dengzhan Xixin Injection (, DZXXI) 30 mL/d by intravenous infusion), for 14 consecutive days. The primary outcome was the Modified Rankin Scale (mRS) score ⩽1 at days 90 after treatment. The secondary outcomes included the National Institute of Health Stroke Scale (NIHSS) score ⩽1, Barthel Index (BI) score ⩾95, and BSS score reduced ⩾30% from baseline at days 14, 30, 60, and 90 after treatment. The safety outcomes included any adverse events during 90 days after treatment. RESULTS: Of the 266 patients included in the effectiveness analysis, 66, 67, 65 and 68 cases were in the low-, medium-, and high-dose HSYAI and control groups, respectively. The proportions of patients in the medium- and high-dose HSYAI groups with mRS score ⩽1 at days 90 after treatment were significantly larger than the control group (P<0.05). The incidences of favorable outcomes of NIHSS and BI at days 90 after treatment as well as satisfactory improvement of BSS at days 30 and 60 after treatment in the medium- and high-dose HSYAI groups were all significantly higher than the control group (P<0.05). No significant difference was reported among the 4 groups in any specific adverse events (P>0.05). CONCLUSIONS: HSYAI was safe and well-tolerated at all doses for treating AIS patients with BSS. The medium (50 mg/d) or high dose (75 mg/d) might be the optimal dose for a phase III trial. (Registration No. ChiCTR-2000029608).

Effects of fish oil and curcumin supplementation on cerebrovascular function in older adults: A randomized controlled trial.

BACKGROUND AND AIMS: Chronic conditions such as obesity, which contribute to endothelial dysfunction in older adults, can cause impairments in cerebrovascular perfusion, which is associated with accelerated cognitive decline. Supplementing the diet with bioactive nutrients that can enhance endothelial function, such as fish oil or curcumin, may help to counteract cerebrovascular dysfunction. METHODS AND RESULTS: A 16-week double-blind, randomized placebo-controlled trial was undertaken in 152 older sedentary overweight/obese adults (50-80 years, body mass index: 25-40 kg/m2) to investigate effects of fish oil (2000 mg docosahexaenoic acid + 400 mg eicosapentaenoic acid/day), curcumin (160 mg/day) or a combination of both on cerebrovascular function (measured by Transcranial Doppler ultrasound), systemic vascular function (blood pressure, heart rate and arterial compliance) and cardiometabolic (fasting glucose and blood lipids) and inflammatory (C-reactive protein) biomarkers. The primary outcome, cerebrovascular responsiveness to hypercapnia, was not affected by the interventions. However, cerebral artery stiffness was significantly reduced in males following fish oil supplementation (P = 0.007). Furthermore, fish oil reduced heart rate (P = 0.038) and serum triglycerides (P = 0.006) and increased HDL cholesterol (P = 0.002). Curcumin did not significantly affect these outcomes either alone or in combination with fish oil. CONCLUSION: Regular supplementation with fish oil but not curcumin improved biomarkers of cardiovascular and cerebrovascular function. The combined supplementation did not result in additional benefits. Further studies are warranted to identify an efficacious curcumin dose and to characterize (in terms of sex, BMI, cardiovascular and metabolic risk factors) populations whose cerebrovascular and cognitive functions might benefit from either intervention. CLINICAL TRIAL REGISTRATION: ACTRN12616000732482p.

Self-Reported Omega-3 Supplement Use Moderates the Association between Age and Exercising Cerebral Blood Flow Velocity in Older Adults.

Cerebral blood flow (CBF) decreases across the lifespan, and chronic conditions such as dementia and stroke accelerate this decline. Impaired CBF results in reduced delivery of oxygen and nutrients, which can damage the brain over time. Thus, there is a need to identify lifestyle interventions, including diet and exercise, to maintain CBF with aging and in the presence of chronic disease. In the present study, we used transcranial Doppler ultrasound to record middle cerebral artery velocity (MCAv), a surrogate measure of CBF, during moderate-intensity exercise in sedentary, cognitively normal older adults (n = 90). A multiple linear regression model (F(4, 85) = 3.21, p = 0.02) showed that self-reported omega-3 supplement use significantly moderated the association between age and mean exercising MCAv in these individuals (p = 0.01). Older age was associated with lower exercising MCAv in the group not taking omega-3 supplements, while exercising MCAv showed no decline with increasing age in the group who reported omega-3 supplement use. These findings suggest omega-3 supplementation may have an important role in the preservation of CBF with aging.

Therapeutic effect of piracetam with nimodipine on vascular dementia after cerebral infarction.

This article investigated the clinical effects of piracetam with nimodipine in the treatment of vascular dementia (VD) after cerebral infarction. 98 patients with vascular dementia after cerebral infarction were selected and divided into the control group and the study group according to the treatment method. The control group was treated with nimodipine alone. The study group was treated with piracetam on the basis of this observation, and we test the ADL (life ability score), MoCA(montreal cognitive assessment scale), ADAS-Cog(alzheimer's scale-cognition), MMSE(mental status examination) scores and quality of life scores before and after treatment in the two groups. Before treatment, there were no significant differences in ADL, MoCA, and ADAS-Cog scores between the two groups (P>0.05). After treatment, the ADL, MoCA, and ADAS-Cog scores of the study group were superior to the control group. The difference was statistically significant (P<0.05). There was no significant difference in MMSE scores between the two groups before treatment and 1 month after treatment (P>0.05). The MMSE scores of the study group were better than the control group after 3 months of treatment and half a year after treatment. The difference was statistically significant (P <0.05). Before treatment, there was no significant difference in the quality of life scores between the two groups (P>0.05). After treatment, the quality of life scores was significantly higher than the control group, and the difference was statistically significant (P<0.05). For patients with vascular dementia after cerebral infarction, piracetam combined with nimodipine can improve the cognitive function, improve the quality of life, and have a significant clinical effect.

The Acute and Chronic Cognitive and Cerebral Blood-Flow Effects of Nepalese Pepper (Zanthoxylum armatum DC.) Extract-A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Humans.

Background: Zanthoxylum armatum DC. (ZA) is a traditional Asian culinary spice and medicinal compound, which is rich in monoterpenes and hydroxy α-sanshool. Mechanistic interactions with the monoamine, cholinergic and cannabinoid neurotransmission systems, as well as transient receptor potential (TRP) and potassium ion channels, may predispose ZA to modulate human brain function. Objectives: To investigate the effects of a single dose and 56-days supplementation with a lipid extract of ZA on cognitive function, mood and cerebral blood-flow (CBF) parameters in the pre-frontal cortex during cognitive task performance. Design: Double-blind, randomized, parallel groups study with N = 82 healthy males and females between the ages of 30 and 55 years. Assessments were undertaken pre-dose and at 1, 3 and 5 hours post-dose on the first (Day 1) and last (Day 56) days of supplementation. Results: A single dose of ZA (Day 1) resulted in acute improvements on a 'Speed of Attention' factor and the Rapid Visual Information Processing (RVIP) task, in comparison to placebo. However, following ZA participants were less accurate on the name-to-face recall task. After 56 days of ZA consumption (Day 56), speed was enhanced on a global 'Speed of Performance' measure, comprising data from all of the timed tasks in the computerized battery. Participants also completed more correct Serial 3s Subtractions at the 3 hours assessment and were less mentally fatigued throughout the day than participants consuming placebo. These effects were complemented on both Day 1 and Day 56 by modulation of CBF parameters, as assessed by Near Infrared Spectroscopy (NIRS). The primary finding here was a reduced hemodynamic response during the RVIP task. Conclusion: ZA improves aspects of cognitive performance, in particular the speed of performing tasks, in healthy humans and results in concomitant reductions in hemodynamic responses in the frontal cortex during task performance. The findings suggest an increase in neural efficiency following ZA.

L-arginine supplementation and thromboxane synthase inhibition increases cerebral blood flow in experimental cerebral malaria.

Cerebral malaria pathogenesis involves vascular dysfunction with low nitric oxide (NO) bioavailability, vasoconstriction and impaired vasodilation, leading to ischemia, tissue hypoxia and ultimately death. Cerebral blood flow (CBF) involves NO and other pathways, including arachidonic acid (AA)-derived metabolites. Here we show that mice with experimental cerebral malaria (ECM) by P. berghei ANKA showed marked decreases in CBF (as assessed by laser speckle contrast imaging - LSCI) and that administration of L-arginine supplementation (50 mg/kg) and/or of the thromboxane synthase inhibitor Ozagrel (100 mg/kg) induced immediate increases in CBF. L-arginine in combination with artesunate (32 mg/kg) induced immediate reversal of brain ischemia in the short-term (1 hour), but the effect subsided after 3 and 6 hours. Neither L-arginine nor Ozagrel reversed blood brain barrier breakdown. Mice with ECM showed brain levels of selected AA-derived metabolites with a vasoconstrictor profile, with increased levels of 8-isoprostanes, 20-HETE and 14,15-DHET, whereas mice infected with a non-ECM-inducing strain of P. berghei (NK65) showed a vasodilator profile, with normal levels of 20-HETE and 14,15-DHET and increased levels of PGE2. L-arginine is capable of partially reversing cerebral ischemia and AA metabolites may play a role in the cerebrovascular dysfunction in ECM.

Does Nimodipine Interruption due to High Catecholamine Doses Lead to a Greater Incidence of Delayed Cerebral Ischemia in the Setting of Aneurysmal Subarachnoid Hemorrhage?

BACKGROUND: Current guidelines recommend the administration of nimodipine for the prevention of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH). However, nimodipine can lead to significant drops in mean arterial pressure and cerebral perfusion pressure. Catecholamines are then used to maintain them while nimodipine is reduced and/or held. There is no evidence that nimodipine retains its neuroprotective effect at lower doses. We aimed to investigate the role of nimodipine interruption in the setting of aSAH and its possible impact on the incidence of DCI. METHODS: We performed a retrospective analysis in patients with aSAH admitted to our center from January 2012 to October 2015. Nimodipine prophylaxis duration and dosage and the incidence of DCI were recorded. Bivariate correlation with Spearman's rho (ρ) and ordinal regression analyses were performed. RESULTS: A total of 170 patients were included in the study. Of these, 165 (97.1%) received nimodipine prophylaxis starting on day 0. Nimodipine was interrupted in 85 of 165 (51.5%), whereas dose was reduced in 47 of 165 (28.5%); full dose was received by only 33 of 165 (20%). DCI was observed in 85 of 170 (50%). Nimodipine interruption correlated in a statistically significant way with a greater incidence of DCI (ρ = 0.431, P < 0.001); receiving full doses of nimodipine showed a statistically significant inverse correlation to DCI (ρ = -0.273, P < 0.001). Ordinal regression analysis revealed nimodipine interruption as a statistically significant independent predictor of DCI (odds ratio 0.194; 95% confidence interval 0.079-0.474, P < 0.001). CONCLUSIONS: Our analysis reveals a greater incidence of DCI in patients with aSAH when nimodipine is interrupted.

Effects of Alcohol and Acetate on Cerebral Blood Flow: A Pilot Study.

BACKGROUND: Acute alcohol produces effects on cerebral metabolism and blood flow. Alcohol is converted to acetate, which serves as a source of energy for the brain and is an agonist at G protein-coupled receptors distributed in different cell types in the body including neurons. Acetate has been hypothesized to play a role in the cerebral blood flow (CBF) response after alcohol ingestion. We tested whether administration of acetate would alter CBF in a pattern similar to or different from that of alcohol ingestion in healthy individuals. METHODS: Twenty-four healthy participants were assigned by convenience to receive either 0.6 g/kg alcohol orally (n = 12) or acetate intravenously (n = 12). For each participant, CBF maps were acquired using an arterial spin labeling sequence on a 3T magnetic resonance scanner after placebo and after drug administration. Whole-brain CBF maps were compared between placebo and drug using a paired t-test, and set at a threshold of p < 0.05 corrected for multiple comparisons (k ≥ 142 voxels, ≥3.78 cm3 ), voxel-level p < 0.005. Intoxication was measured after placebo and drug administration with a Subjective High Assessment Scale (SHAS-7). RESULTS: Compared to placebo, alcohol and acetate were associated with increased CBF in the medial thalamus. Alcohol, but not acetate, was associated with increased CBF in the right orbitofrontal, medial prefrontal and cingulate cortex, and hippocampus. Plasma acetate levels increased following administration of alcohol and acetate and did not differ between the 2 arms. Alcohol, but not acetate, was associated with an increase in SHAS-7 scores (p < 0.001). CONCLUSIONS: Increased thalamic CBF associated with either alcohol or acetate administration suggests that the thalamic CBF response after alcohol could be mediated by acetate. Compared to other brain regions, thalamus may differ in its ability to metabolize acetate or expression of receptors responsive to acetate. Increased prefrontal and limbic CBF associated with alcohol may be linked to alcohol's behavioral effects.

Dietary nitrate supplementation enhances cerebrovascular CO2 reactivity in a sex-specific manner.

Insufficient nitric oxide (NO) bioavailability plays an important role in endothelial dysfunction, and increased NO has the potential to enhance cerebral blood flow (CBF). Dietary supplementation with sodium nitrate, a precursor of NO, could improve cerebrovascular function, but this has not been investigated. In 17 individuals, we examined the effects of a 7-day supplementation of dietary nitrate (0.1 mmol·kg-1·day -1) on cerebrovascular function using a randomized, single-blinded placebo-controlled crossover design. We hypothesized that 7-day dietary nitrate supplementation increases CBF response to CO2 (cerebrovascular CO2 reactivity) and cerebral autoregulation (CA). We assessed middle cerebral artery blood velocity (MCAv) and blood pressure (BP) at rest and during CO2 breathing. Transfer function analysis was performed on resting beat-to-beat MCAv and BP to determine CA, from which phase, gain, and coherence of the BP-MCAv data were derived. Dietary nitrate elevated plasma nitrate concentration by ~420% (P < 0.001) and lowered gain (d = 1.2, P = 0.025) and phase of the BP-MCAv signal compared with placebo treatment (d = 0.7, P = 0.043), while coherence was unaffected (P = 0.122). Dietary nitrate increased the MCAv-CO2 slope in a sex-specific manner (interaction: P = 0.016). Dietary nitrate increased the MCAv-CO2 slope in men (d = 1.0, P = 0.014 vs. placebo), but had no effect in women (P = 0.919). Our data demonstrate that dietary nitrate greatly increased cerebrovascular CO2 reactivity in healthy individuals, while its effect on CA remains unclear. The selective increase in the MCAv-CO2 slope observed in men indicates a clear sexual dimorphic role of NO in cerebrovascular function.NEW & NOTEWORTHY We found dietary nitrate supplementation improved the brain blood vessels' response to CO2, cerebrovascular CO2 reactivity, without affecting blood pressure in a group of healthy individuals. Meanwhile, the effect of dietary nitrate on the relationship between blood pressure and brain blood flow, cerebral autoregulation, was inconclusive. The improvement in cerebrovascular CO2 reactivity was only observed in the male participants, alluding to a sex difference in the effect of dietary nitrate on brain blood flow control. Our findings indicate that dietary nitrate could be an effective strategy to enhance cerebrovascular CO2 reactivity.

Efficacy and safety of oral traditional Chinese patent medicine for chronic cerebral circulation insufficiency patients: A protocol for a systematic review and network meta-analysis.

BACKGROUND: Chronic cerebral circulation insufficiency (CCCI) is a common clinical cerebrovascular disease, especially among middle-aged and elderly patients, which seriously endangers their quality of life and physical and mental health. At present, Oral traditional Chinese patent medicine (OTCPM) is widely used in the treatment of CCCI in China, but its actual efficacy and safety lack of evidence-based evidence. Therefore, we will screen out the most effective OTCPM through a systematic review and network meta-analysis to provide a reliable theoretical basis for clinical decisions. METHODS: We will search electronic databases to collect relevant RCT studies from inception to October 2019. Those electronic databases include PubMed, Cochrane Library, Web of Science, EMBASE, China Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Chinese Scientific Journal Database (VIP), and Wan-fang database. Only randomized clinical trials (RCTs) concerned any OTCPM treatments for CCCI will be collected. The included studies will no restrictions on language or publication year. There were no publication year or language for the included literature. Risk bias tools will assess the quality of the included literature. A Bayesian NMA will be performed to combine the direct and indirect comparisons of TCPMs interventions. The surface under the cumulative ranking curve (SUCRA) will be drawn to display the hierarchy of each TCPMs treatment. All statistical analyses will be implemented using R v3.5.2. and GeMTC v1.4.3.We will publish this systematic review in academic journals. Since this literature review will not involve directly contacting patients, ethical approval and informed consent are not required. TRIAL REGISTRATION NUMBER: CRD42019123878.