Abstract Near-infrared spectroscopy (NiRS) is a relatively new technology of brain imaging with its potential in the assessment of cerebrovascular health only recently discovered. Encouraging early results suggest that NiRS can be used as an inexpensive and portable cerebrovascular health tracking device using a recently proposed pulse relaxation function (PReFx). In this paper, we propose a new NiRS timing index, $$\text {TI}_{\rm NiRS}$$ TINiRS , of cerebrovascular health. $$\text {TI}_{\rm NiRS}$$ TINiRS is a novel use of the NiRS technology. $$\text {TI}_{\rm NiRS}$$ TINiRS is motivated by the previously proved relationship of the timing of the reflected wave with vascular resistance and compliance in the context of pressure waveforms. We correlated both $$\text {TI}_{\rm NiRS}$$ TINiRS and PReFx against age, a non-exercise cardiorespiratory fitness (CRF) index, and two existing indices of cerebrovascular health, namely transcranial Doppler (TCD) augmentation index, $$\text {AI}_{\rm TCD}$$ AITCD , and magnetic resonance imaging (MRI) blood flow pulsatility index, $$\text {PI}_{\rm MRI}$$ PIMRI . The $$\text {TI}_{\rm NiRS}$$ TINiRS correlations with Age, CRF, $$\text {PI}_{\rm MRI}$$ PIMRI and $$\text {AI}_{\rm TCD}$$ AITCD all are significant, i.e., $$r=0.53$$ r=0.53 ( $$p=0.002$$ p=0.002 ), $$r=-0.44$$ r=-0.44 ( $$p=0.011$$ p=0.011 ), $$r=0.45$$ r=0.45 ( $$p=0.012$$ p=0.012 ) and $$r=0.46$$ r=0.46 ( $$p=0.010$$ p=0.010 ), respectively. PReFx, however, did not have significant correlations with any of the vascular health factors. The proposed timing index is a reliable indicator of cerebrovascular aging factors in the NiRS waveform.
Temperate rocky reefs are complex habitats that support high levels of biodiversity and productivity. However, the sessile benthic communities attached to these reefs are vulnerable to climate change and local human impacts due to their limited capacity to rapidly avoid unfavourable environments. In southeastern Australia, high latitude rocky reefs face increasing threats from rapid warming, surpassing the global average. Existing management efforts for these reefs rely heavily on research from tropical coral ecosystems and shallow temperate algal-dominated rocky reefs, where sufficient data allows for reliable predictions on the future state of the systems. Recent evidence from seabed mapping programs indicates that mesophotic reefs (~30-150 m depth) are equally or more extensive than shallow systems in temperate waters. They provide novel ecosystem functions and could potentially act as climate refuges for some components of shallow water communities that extend across depth strata. However, despite their importance, very little is known about the threats faced by non-algal sessile organisms in either shallow water or mesophotic systems in many parts of the world, including temperate Australia. This review examined the current state of knowledge regarding the direct impact of physical disturbances, such as extreme weather events, ocean warming and destructive fishing practices, on sessile mesophotic communities in general. We then used this to infer the likely drivers of change in temperate mesophotic systems. We found that Australia’s temperate mesophotic ecosystems were less likely to be impacted by fishing, anchoring and lost fishing gears compared to the northern hemisphere due to lower population density. Instead, we identified present and future pulsed warming events and severe storms as major threats to Australia’s mesophotic systems. This conclusion is based on the lack of evidence supporting the existence of depth refuges from climate events in the current literature and the potential implications of the predicted future increases in high wind-wave energy and warming extending into the mesophotic depths. Drawing from observations globally, changes in the distribution of growth forms, size or diversity of sponges may be useful indicators of heat stress and seabed disturbances in temperate mesophotic systems.
This methodological paper presents both a scientific rationale and a methodological approach for investigating the effects of resveratrol supplementation on mood and cognitive performance in postmenopausal women. Postmenopausal women have an increased risk of cognitive decline and dementia, which may be at least partly due to loss of beneficial effects of estrogen on the cerebrovasculature. We hypothesise that resveratrol, a phytoestrogen, may counteract this risk by enhancing cerebrovascular function and improving regional blood flow in response to cognitive demands. A clinical trial was designed to test this hypothesis.Healthy postmenopausal women were recruited to participate in a randomised, double-blind, placebo-controlled (parallel comparison) dietary intervention trial to evaluate the effects of resveratrol supplementation (75 mg twice daily) on cognition, cerebrovascular responsiveness to cognitive tasks and overall well-being. They performed the following tests at baseline and after 14 weeks of supplementation: Rey Auditory Verbal Learning Test, Cambridge Semantic Memory Battery, the Double Span and the Trail Making Task. Cerebrovascular function was assessed simultaneously by monitoring blood flow velocity in the middle cerebral arteries using transcranial Doppler ultrasound.This trial provides a model approach to demonstrate that, by optimising circulatory function in the brain, resveratrol and other vasoactive nutrients may enhance mood and cognition and ameliorate the risk of developing dementia in postmenopausal women and other at-risk populations.
Curcumin has previously been shown to enhance mood in non-depressed older adults. However, observed benefits were limited to short-term supplementation (4 weeks). In a 16 week randomized, double-blind, placebo-controlled, 2 × 2 factorial design trial, we supplemented overweight or obese non-depressed adults (50-80 years) with curcumin (160 mg/day), fish oil (2000 mg docosahexaenoic acid +400 mg eicosapentaenoic acid/day), or a combination of both. Secondary outcomes included mental wellbeing measures (mood states and subjective memory complaints (SMCs)) and quality of life (QoL). Furthermore, plasma apolipoprotein E4 (APOE4) was measured to determine whether APOE4 status influences responses to fish oil. Curcumin improved vigour (p = 0.044) compared to placebo and reduced SMCs compared to no curcumin treatment (p = 0.038). Fish oil did not affect any mood states, SMCs or QoL; however, responses to fish oil were affected by APOE4 status. In APOE4 non-carriers, fish oil increased vigour (p = 0.030) and reduced total mood disturbances (p = 0.048) compared to placebo. Improvements in mental wellbeing were correlated with increased QoL. Combining curcumin with fish oil did not result in additive effects. This exploratory analysis indicates that regular supplementation with either curcumin or fish oil (limited to APOE4 non-carriers) has the potential to improve some aspects of mental wellbeing in association with better QoL.
Abstract Introduction Impairment of cerebrovascular function becomes evident after menopause. No study has yet explored relationships between deficits in cerebrovascular function, cognitive performance, and mood in postmenopausal women. Method Cerebrovascular function was assessed in 80 healthy postmenopausal women by monitoring blood flow velocity (BFV) in the middle and posterior cerebral arteries using transcranial Doppler ultrasound at rest, following a hypercapnic challenge, and during performance of a cognitive test battery; the latter assessed domains of memory and executive functions. Various measures of mood (i.e., Profile of Mood States and Center for Epidemiological Studies Depression Scale) were also assessed. Results Cerebral artery elasticity and BFV responsiveness to cognitive tests (neurovascular coupling) correlated with cognitive performance but not with depressive symptoms or mood states. Mood deficits were related to poor cognitive performance. Conclusion These results highlight the importance of adequate cerebral perfusion for optimized cognitive function in healthy postmenopausal women. Preventative strategies to attenuate accelerated cognitive decline should also consider restoring cerebrovascular function.
Background: Poor cerebral perfusion may contribute to cognitive impairment in type 2 diabetes mellitus (T2DM). We conducted a randomized controlled trial to test the hypothesis that resveratrol can enhance cerebral vasodilator function and thereby alleviate the cognitive deficits in T2DM. We have already reported that acute resveratrol consumption improved cerebrovascular responsiveness (CVR) to hypercapnia. We now report the effects of resveratrol on neurovascular coupling capacity (CVR to cognitive stimuli), cognitive performance and correlations with plasma resveratrol concentrations. Methods: Thirty-six T2DM adults aged 40–80 years were randomized to consume single doses of resveratrol (0, 75, 150 and 300 mg) at weekly intervals. Transcranial Doppler ultrasound was used to monitor changes in blood flow velocity (BFV) during a cognitive test battery. The battery consisted of dual-tasking (finger tapping with both Trail Making task and Serial Subtraction 3 task) and a computerized multi-tasking test that required attending to four tasks simultaneously. CVR to cognitive tasks was calculated as the per cent increase in BFV from pre-test basal to peak mean blood flow velocity and also as the area under the curve for BFV. Results: Compared to placebo, 75 mg resveratrol significantly improved neurovascular coupling capacity, which correlated with plasma total resveratrol levels. Enhanced performance on the multi-tasking test battery was also evident following 75 mg and 300 mg of resveratrol. Conclusion: a single 75 mg dose of resveratrol was able to improve neurovascular coupling and cognitive performance in T2DM. Evaluation of benefits of chronic resveratrol supplementation is now warranted.
We compared the differences in cerebrovascular and cognitive function between 13 aerobic exercise trained, older adults and 13 age-, height- and sex-matched sedentary, untrained controls. We determined whether other measures accounted for differences in cerebrovascular and cognitive function between these groups and examined the associations between these functions. Participants undertook anthropometric, mood, cardiovascular, exercise performance, strength, cerebrovascular, and cognitive measurements, and a blood collection. Transcranial Doppler ultrasonography determined cerebrovascular responsiveness (CVR) to hypercapnia and cognitive stimuli. The trained group had a higher CVR to hypercapnia (80.3 ± 7.2 vs 35.1 ± 6.7%, P < 0.001), CVR to cognitive stimuli (30.1 ± 2.9 vs 17.8 ± 1.4%, P = 0.001) and total composite cognitive score (117 ± 2 vs 98 ± 4, P < 0.001) than the controls. These parameters no longer remained statistically different between the groups following adjustments for covariates. There were positive correlations between the total composite cognitive score and CVR to hypercapnia (r = 0.474, P = 0.014) and CVR to cognitive stimuli (r = 0.685, P < 0.001). We observed a relationship between cerebrovascular and cognitive function in older adults and an interaction between regular lifelong aerobic exercise training and cardiometabolic factors that may directly influence these functions.
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