Wild Blueberry Extract Intervention in Healthy Older Adults: A Multi-Study, Randomised, Controlled Investigation of Acute Cognitive and Cardiovascular Effects.

BACKGROUND: Circadian and homeostatic declines in cognitive performance are observed during the day, most commonly at 14:00. Additionally, postprandial reductions in cognitive ability have been widely demonstrated 1 h after lunch consumption, affecting domains of executive functioning (EF), episodic memory (EM), and attention. Existing evidence shows that anthocyanin-rich foods such as berries may improve or attenuate the decline in EF and EM in ageing adults. Further research is required to assess whether extracts such as wild blueberry extract (WBE) may be beneficial for cognitive function across an acute timeframe, including known periods of reduced functioning. OBJECTIVES: (1) Study 1: ROAB: To investigate the efficacy of WBE in maintaining EF and EM throughout the day alongside measures of cardiovascular outcomes in healthy older adults. A range of WBE doses were utilised to identify the optimal dose at which cognitive and cardiovascular effects occur. (2) Study 2: BEAT: To replicate alleviation of cognitive decline during a predicted post-lunch dip whilst also improving cardiovascular outcomes following acute WBE 222 mg supplementation. METHODS: Both studies employed a randomised, double-blind, cross-over, placebo-controlled design to explore the effects of WBE intervention versus placebo on several outcomes, including EM, EF, blood pressure, and heart rate in a healthy older adult population (aged 68-75). In ROAB, 28 participants received a single dose of WBE 111 mg, 222 mg, 444 mg, or 888 mg or placebo over a 5-week period, each separated by a 1-week washout. Outcomes were measured at 0 h, 2 h, 4 h, and 6 h post intervention, with intervention occurring immediately after baseline (0 h). In BEAT, 45 participants received WBE 222 mg and placebo (1-week washout). Outcomes were measured at 0 h and 6 h (14:00) when a post-lunch dip was anticipated. This was further enhanced by consumption of lunch 1 h prior to cognitive testing. The WBE 222 mg intervention aligned with known peaks in plasma blueberry polyphenol metabolites at 2 h post dosing, which would coincide with a predicted drop in post-lunch performance. RESULTS: ROAB: A significant dip in executive function was apparent at the 4 h timepoint for placebo only, indicating attenuation for WBE doses. Strikingly, WBE 222 mg produced acute reductions in both systolic and diastolic blood pressure compared with placebo. BEAT: EF reaction time was found to be significantly faster for WBE 222 compared to placebo at the predicted post-lunch dip (14:00), with no other notable benefits on a range of cognitive and cardiovascular outcomes. CONCLUSION: These two studies indicate that WBE may have cardiovascular benefits and attenuate the natural cognitive decline observed over the course of the day, particularly when a decline is associated with a circadian rhythm-driven postprandial dip. However, it is important to acknowledge that effects were subtle, and benefits were only observed on a small number of outcomes. Further research is required to explore the utility of WBE in populations already experiencing mild cognitive impairments.

A randomized, placebo-controlled trial investigating the acute and chronic benefits of American Ginseng (Cereboost®) on mood and cognition in healthy young adults, including in vitro investigation of gut microbiota changes as a possible mechanism of action.

PURPOSE: Cereboost®, an American ginseng extract, has shown improved short-term memory and attention/alertness in healthy young and middle-aged individuals, potentially via modulation of the gut microbiome and upregulation of neurotransmitters such as acetylcholine. Here, we explored the effects of Cereboost® on cognition and mood in the first 6 h post intervention (acute), after 2 weeks daily supplementation (chronic), and whether 2 weeks daily supplementation altered the response to a single acute dose (acute-on-chronic). A concurrent in vitro study evaluated effects of repeated Cereboost® administration on human gut microbiota. METHODS: Cognitive effects of Cereboost® were assessed using a double-blind, randomized, placebo-controlled clinical trial, with 61 healthy young adults. Modulation of the gut microbiome was concurrently modelled using the Simulator of the Human Microbial Ecosystem (SHIME®), using a young adult donor. RESULTS: Consistent with previous findings, Cereboost® improved working memory and attention during the immediate postprandial period; effects that were amplified following two weeks' treatment (acute-on-chronic) compared to acute testing alone. Chronic supplementation improved cognition on an acetylcholine-sensitive attention task and improved mental fatigue and self-assurance aspects of mood. The parallel in vitro study revealed significantly increased acetate, propionate, and butyrate levels in simulated proximal and distal colon regions, linked with observed increases in Akkermansia muciniphila and Lactobacillus. CONCLUSION: This study confirmed the promising effects of Cereboost® on cognitive function and mood, while suggesting a possible link to alterations of the gut microbiome and modulation of acetylcholine. Further studies will be required to unravel the underlying mechanisms that are involved. REGISTRATION: The study was pre-registered at ClinicalTrials.gov on 6th July 2018 (Identifier: NCT03579095).

Effect of Rubus idaeus Extracts in Murine Chondrocytes and Explants.

Osteoarthritis is characterized by cartilage loss resulting from the activation of chondrocytes associated with a synovial inflammation. Activated chondrocytes promote an increased secretion of matrix proteases and proinflammatory cytokines leading to cartilage breakdown. Since natural products possess anti-inflammatory properties, we investigated the direct effect of Rubus idaeus extracts (RIE) in chondrocyte metabolism and cartilage loss. The effect of RIE in chondrocyte metabolism was analyzed in murine primary chondrocytes and cartilage explants. We also assessed the contribution of RIE in an inflammation environment by culturing mice primary chondrocytes with the supernatant of Raw 264.7 macrophage-like cells primed with RIE. In primary chondrocytes, RIE diminished chondrocyte hypertrophy (Col10), while increasing the expression of catabolic genes (Mmp-3, Mmp-13) and reducing anabolic genes (Col2a1, Acan). In cartilage explants, Rubus idaeus prevented the loss of proteoglycan (14.84 ± 3.07% loss of proteoglycans with IL1 alone vs. 3.03 ± 1.86% with IL1 and 100 µg/mL of RIE), as well as the NITEGE neoepitope expression. RIE alone reduced the expression of Il1 and Il6 in macrophages, without changes in Tnf and Cox2 expression. The secretome of macrophages pre-treated with RIE and transferred to chondrocytes decreases the gene and protein expression of Mmp-3 and Cox2. In conclusion, these data suggest that RIE may protect from chondrocyte catabolism and cartilage loss in inflammatory conditions. Further evaluations are need before considering RIE as a candidate for the treatment for osteoarthritis.

Effects of Panax quinquefolius (American ginseng) on the steady state visually evoked potential during cognitive performance.

OBJECTIVE: To investigate the effects of acute Panax quinquefolius (American ginseng) administration on steady state visually evoked potentials (SSVEPs) during completion of working memory and continuous performance tasks. METHODS: A randomised, double-blind, placebo controlled, balanced, cross-over trial was conducted in middle-aged volunteers aged between 40 and 60 years. Participants were administered 200 mg P. quinquefolius and placebo on two separate testing sessions. Six-h post-dose participants completed spatial working memory (SWM) and continuous performance (CP) tasks while SSVEP from a diffuse task-irrelevant 13 Hz flicker was recorded. RESULTS: During SWM retrieval, P. quinquefolius was associated with significantly reduced prefrontal SSVEP latency. There were no significant treatment effects on CP nor behavioural performance of either task. CONCLUSIONS: These findings provide preliminary evidence of increased recruitment of prefrontal brain regions during working memory processing following a single acute dose of P. quinquefolius.

Extended-access, but not limited-access, methamphetamine self-administration induces behavioral and nucleus accumbens dopamine response changes in rats.

To better understand the neurobiology of methamphetamine (METH) dependence and the cognitive impairments induced by METH use, we compared the effects of extended (12 h) and limited (1 h) access to METH self-administration on locomotor activity and object place recognition, and on extracellular dopamine levels in the nucleus accumbens and caudate-putamen. Rats were trained to self-administer intravenous METH (0.05 mg/kg). One group had progressively extended access up to 12-h sessions. The other group had limited-access 1-h sessions. Microdialysis experiments were conducted during a 12-h and 1-h session, in which the effects of a single METH injection (self-administered, 0.05 mg/kg, i.v.) on extracellular dopamine levels were assessed in the nucleus accumbens and caudate-putamen compared with a drug-naive group. The day after the last 12-h session and the following day experimental groups were assessed for their locomotor activities and in a place recognition procedure, respectively. The microdialysis results revealed tolerance to the METH-induced increases in extracellular dopamine only in the nucleus accumbens, but not in the caudate-putamen in the extended-access group compared with the control and limited-access groups. These effects may be associated with the increased lever-pressing and drug-seeking observed during the first hour of drug exposure in the extended-access group. This increase in drug-seeking leads to higher METH intake and may result in more severe consequences in other structures responsible for the behavioral deficits (memory and locomotor activity) observed in the extended-access group, but not in the limited-access group.

Phencyclidine withdrawal disrupts episodic-like memory in rats: reversal by donepezil but not clozapine.

Episodic memory is the capacity to recall an event in time and place (What? Where? When?). Impaired episodic memory is a debilitating cognitive symptom in schizophrenia but is poorly controlled by currently available antipsychotic drugs. Consistent with glutamatergic abnormality in schizophrenia, the NDMA receptor antagonist, phencyclidine (PCP), induces persistent 'schizophrenia-like' symptoms including memory deficits in humans and rodents and is widely used as an animal model of the disorder. However, in contrast to humans, PCP and PCP withdrawal-induced memory deficits in rodents are reversed by antipsychotic drugs such as clozapine. One possible explanation is that the memory tasks used in animal studies do not simultaneously test the What? Where? When? components that characterize episodic memory in human tasks. We investigated whether subchronic PCP withdrawal disrupts memory in rats in a task that requires simultaneous integration of memory for object, place and context. Rats learn to discriminate objects under specific spatial and contextual conditions analogous to the What? Where? When? components of human episodic memory. We found that PCP withdrawal impaired performance on this task and that the atypical antipsychotic drug clozapine did not reverse this impairment. However the acetylcholinesterase inhibitor (AChEI) donepezil, which has been shown to improve episodic memory in humans did reverse the effect of PCP. This suggests that PCP withdrawal disruption of object-place-context recognition in rats may prove to be a useful model to investigate episodic memory impairment in schizophrenia and supports the suggestion that AChEIs could prove to be a useful pharmacological strategy to specifically treat episodic memory problems in schizophrenia.