Somatostatin neurons in prefrontal cortex initiate sleep-preparatory behavior and sleep via the preoptic and lateral hypothalamus.

The prefrontal cortex (PFC) enables mammals to respond to situations, including internal states, with appropriate actions. One such internal state could be 'tiredness'. Here, using activity tagging in the mouse PFC, we identified particularly excitable, fast-spiking, somatostatin-expressing, γ-aminobutyric acid (GABA) (PFCSst-GABA) cells that responded to sleep deprivation. These cells projected to the lateral preoptic (LPO) hypothalamus and the lateral hypothalamus (LH). Stimulating PFCSst-GABA terminals in the LPO hypothalamus caused sleep-preparatory behavior (nesting, elevated theta power and elevated temperature), and stimulating PFCSst-GABA terminals in the LH mimicked recovery sleep (non-rapid eye-movement sleep with higher delta power and lower body temperature). PFCSst-GABA terminals had enhanced activity during nesting and sleep, inducing inhibitory postsynaptic currents on diverse cells in the LPO hypothalamus and the LH. The PFC also might feature in deciding sleep location in the absence of excessive fatigue. These findings suggest that the PFC instructs the hypothalamus to ensure that optimal sleep takes place in a suitable place.

Does omega-3 supplementation improve the inflammatory profile of patients with heart failure? a systematic review and meta-analysis.

Omega-3 fatty acids are potential anti-inflammatory agents that may exert beneficial outcomes in diseases characterised by increased inflammatory profile. The purpose of this study was to comprehensively evaluate the existing research on the effectiveness of n-3 fatty acid supplementation in lowering levels of circulating inflammatory cytokines in patients with heart failure (HF). From the beginning until October 2022, randomised controlled trials (RCTs) were the subject of PubMed, Scopus, Web of Science, and Cochrane Library literature search. Omega-3 fatty acid supplementation vs. placebo were compared in eligible RCTs to see how they affected patients with HF in terms of inflammation, primarily of tumour necrosis factor-alpha (TNF-a), interleukin-6 (IL-6), and c-reactive protein (CRP). A meta-analysis employing the random effects inverse-variance model and standardised mean differences was performed to assess group differences. Ten studies were included in this systematic review and meta-analysis. Our main analysis (k = 5) revealed a beneficial response of n-3 fatty acid supplementation on serum TNF-a (SMD: - 1.13, 95% CI: - 1.75- - 0.50, I2 = 81%, P = 0.0004) and IL-6 levels (k = 4; SMD: - 1.27, 95% CI: - 1.88- - 0.66, I2 = 81%, P < 0.0001) compared to placebo; however, no changes were observed in relation to CRP (k = 6; SMD: - 0.14, 95% CI: - 0.35-0.07, I2 = 0%, P = 0.20). Omega-3 fatty acid supplementation may be a useful strategy for reducing inflammation in patients with HF, but given the paucity of current studies, future studies may increase the reliability of these findings.

The impact of branched-chain amino acid supplementation on measures of glucose homeostasis in individuals with hepatic disorders: A systematic review of clinical studies.

BACKGROUND: Branched chain amino acid (BCAA) supplementation may influence glucose metabolism in individuals with an impaired glyceamic profile. This systematic review investigated the effects of isolated BCAA supplementation on measures of glucose homeostasis in individuals with hepatic disorders. METHODS: We searched PubMed, Web of Science, Cochrane Library and Scopus for published clinical trials that investigated the effects of isolated BCAA supplementation on measures of glucose homeostasis, including serum glucose and insulin, glycated haemoglobin (HbA1c) levels and homeostatic model assessment for insulin resistance (HOMA-IR) scores. RESULTS: Eleven trials met the inclusion criteria. Only one study revealed a decrease in serum glucose from BCAA supplementation compared to three studies that showed increases. Five studies demonstrated no significant changes in serum glucose, and two studies displayed no changes in HbA1c following BCAA supplementation. Serum levels of insulin were decreased in three studies, remained unchanged in one, and increased in the remaining three studies. BCAA supplementation reduced HOMA-IR scores in two studies, increased HOMA-IR scores in another two, or resulted in no changes in two other studies. CONCLUSIONS: BCAA supplementation in isolation had no effect on overall glucose homeostasis in individuals with hepatic disorders, although some improvements on serum insulin levels and HOMA-IR scores were observed. Overall, there is little evidence to support the utilisation of BCAA supplementation as a potential nutritional strategy for improving measures of glucose homeostasis in individuals with hepatic disorders.

Effects of creatine supplementation on memory in healthy individuals: a systematic review and meta-analysis of randomized controlled trials.

CONTEXT: From an energy perspective, the brain is very metabolically demanding. It is well documented that creatine plays a key role in brain bioenergetics. There is some evidence that creatine supplementation can augment brain creatine stores, which could increase memory. OBJECTIVE: A systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to determine the effects of creatine supplementation on memory performance in healthy humans. DATA SOURCES: The literature was searched through the PubMed, Web of Science, Cochrane Library, and Scopus databases from inception until September 2021. DATA EXTRACTION: Twenty-three eligible RCTs were initially identified. Ten RCTs examining the effect of creatine supplementation compared with placebo on measures of memory in healthy individuals met the inclusion criteria for systematic review, 8 of which were included in the meta-analysis. DATA ANALYSIS: Overall, creatine supplementation improved measures of memory compared with placebo (standard mean difference [SMD] = 0.29, 95%CI, 0.04-0.53; I2 = 66%; P = 0.02). Subgroup analyses revealed a significant improvement in memory in older adults (66-76 years) (SMD = 0.88; 95%CI, 0.22-1.55; I2 = 83%; P = 0.009) compared with their younger counterparts (11-31 years) (SMD = 0.03; 95%CI, -0.14 to 0.20; I2 = 0%; P = 0.72). Creatine dose (≈ 2.2-20 g/d), duration of intervention (5 days to 24 weeks), sex, or geographical origin did not influence the findings. CONCLUSION: Creatine supplementation enhanced measures of memory performance in healthy individuals, especially in older adults (66-76 years). SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. 42021281027.

Medium-chain triglycerides may improve memory in non-demented older adults: a systematic review of randomized controlled trials.

BACKGROUND: Ketosis has been exploited for its neuroprotective impact and treatment of neurological conditions via ketone production. Exogenous medium-chain triglyceride (MCT) supplementation may induce nutritional ketosis. The aim of this systematic review is to explore the effects of MCTs on memory function in older adults without cognitive impairment. METHODS: A systematic literature search of PubMed, Cochrane Library, Scopus, and Web of Science was employed from inception until April 2022 for randomized controlled trials (RCTs) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, investigating the impact of MCT oils on components of memory. Risk of bias (RoB2) tool was utilized for quality assessment. RESULTS: Six trials were included for qualitative synthesis, in which two studies examined the effect of MCTs through a ketogenic meal. MCT supplementation compared to controls was associated with improved indices of memory function in 4 out of 6 studies, particularly working memory. A meta-analysis was not employed due to the low number of studies, therefore, a true effect measure of MCT supplementation was not explored. CONCLUSIONS: MCT supplementation may enhance working memory in non-demented older adults. These effects may be more prominent in individuals with lower baseline scores, from short and long-term supplementation. Further studies are warranted to confirm these findings in terms of optimal dose and MCTs composition, which may protect from memory decline during aging.

Exercise and nutritional interventions on sarcopenia and frailty in heart failure: a narrative review of systematic reviews and meta-analyses.

The purpose of this review is to describe the present evidence for exercise and nutritional interventions as potential contributors in the treatment of sarcopenia and frailty (i.e. muscle mass and physical function decline) and the risk of cardiorenal metabolic comorbidity in people with heart failure (HF). Evidence primarily from cross-sectional studies suggests that the prevalence of sarcopenia in people with HF is 37% for men and 33% for women, which contributes to cardiac cachexia, frailty, lower quality of life, and increased mortality rate. We explored the impact of resistance and aerobic exercise, and nutrition on measures of sarcopenia and frailty, and quality of life following the assessment of 35 systematic reviews and meta-analyses. The majority of clinical trials have focused on resistance, aerobic, and concurrent exercise to counteract the progressive loss of muscle mass and strength in people with HF, while promising effects have also been shown via utilization of vitamin D and iron supplementation by reducing tumour necrosis factor-alpha (TNF-a), c-reactive protein (CRP), and interleukin-6 (IL-6) levels. Experimental studies combining the concomitant effect of exercise and nutrition on measures of sarcopenia and frailty in people with HF are scarce. There is a pressing need for further research and well-designed clinical trials incorporating the anabolic and anti-catabolic effects of concurrent exercise and nutrition strategies in people with HF.

Effects of Creatine Supplementation on Brain Function and Health.

While the vast majority of research involving creatine supplementation has focused on skeletal muscle, there is a small body of accumulating research that has focused on creatine and the brain. Preliminary studies indicate that creatine supplementation (and guanidinoacetic acid; GAA) has the ability to increase brain creatine content in humans. Furthermore, creatine has shown some promise for attenuating symptoms of concussion, mild traumatic brain injury and depression but its effect on neurodegenerative diseases appears to be lacking. The purpose of this narrative review is to summarize the current body of research pertaining to creatine supplementation on total creatine and phophorylcreatine (PCr) content, explore GAA as an alternative or adjunct to creatine supplementation on brain creatine uptake, assess the impact of creatine on cognition with a focus on sleep deprivation, discuss the effects of creatine supplementation on a variety of neurological and mental health conditions, and outline recent advances on creatine supplementation as a neuroprotective supplement following traumatic brain injury or concussion.

Effect of vitamin D monotherapy on indices of sarcopenia in community-dwelling older adults: a systematic review and meta-analysis.

BACKGROUND: Vitamin D supplementation is proposed as a potentially effective nutritional intervention to mitigate the risk of sarcopenia. The aim of this systematic review and meta-analysis was to investigate the impact of vitamin D supplementation monotherapy on indices of sarcopenia in community-dwelling older adults. METHODS: A comprehensive search of the literature was conducted in PubMed, Web of Science, Scopus, and Cochrane Library. Eligible randomized controlled trials (RCTs) compared the effect of vitamin D supplementation (as monotherapy) with placebo on indices of sarcopenia in older (>50 years) adults. Using the random effects inverse-variance model, we calculated the mean difference (MD) in handgrip strength (HGS), short physical performance battery (SPPB), timed up and go (TUG), and appendicular lean mass (ALM) between groups. We also calculated the standardized mean difference (SMD) in general muscle strength and general physical performance (composite plot of all muscle strength and physical performance outcomes, respectively) between groups. RESULTS: Ten RCTs were included in the meta-analysis. A significant decrease in SPPB scores was observed with vitamin D supplementation compared with placebo (MD: -0.23; 95% CI -0.40 to -0.06; I2  = 0%; P = 0.007). Vitamin D supplementation conferred no effect on HGS (MD: -0.07 kg; 95% CI -0.70 to 0.55; I2  = 51%, P = 0.82), TUG (MD: 0.07 s; 95% CI -0.08 to 0.22; I2  = 0%, P = 0.35), ALM (MD: 0.06 kg/m2 ; 95% CI: -0.32 to 0.44; I2  = 73%, P = 0.77), general muscle strength (SMD: -0.01; 95% CI -0.17 to 0.15; I2  = 42%, P = 0.90), or general physical performance (SMD: -0.02; 95% CI -0.23 to 0.18; I2  = 71%, P = 0.83). CONCLUSIONS: Vitamin D supplementation did not improve any sarcopenia indices in community-dwelling older adults and may compromise some aspects of physical performance. Future studies are warranted to investigate the impact of vitamin D supplementation on individual indices of SPPB, including mobility and balance, in older adults.

The Relation between Caffeine Consumption and Endometriosis: An Updated Systematic Review and Meta-Analysis.

While the contributing factors leading to endometriosis remain unclear, its clinical heterogeneity suggests a multifactorial causal background. Amongst others, caffeine has been studied extensively during the last decade as a putative contributing factor. In this systematic review and meta-analysis, we provide an overview/critical appraisal of studies that report on the association between caffeine consumption and the presence of endometriosis. In our search strategy, we screened PubMed and Scopus for human studies examining the above association. The main outcome was the relative risk of endometriosis in caffeine users versus women consuming little or no caffeine (<100 mg/day). Subgroup analyses were conducted for different levels of caffeine intake: high (>300 mg/day) or moderate (100-300 mg/day). Ten studies were included in the meta-analysis (five cohort and five case-control studies). No statistically significant association was observed between overall caffeine consumption and risk for endometriosis (RR 1.12, 95% confidence interval (CI) 0.97-1.28, I2 = 70%) when compared to little or no (<100 mg/day) caffeine intake. When stratified according to level of consumption, high intake was associated with increased risk of endometriosis (RR 1.30, 95%CI 1.04-1.63, I2 = 56%), whereas moderate intake did not reach nominal statistical significance (RR 1.18, 95%CI 0.99-1.40, I2 = 37%). In conclusion, caffeine consumption does not appear to be associated with increased risk for endometriosis. However, further research is needed to elucidate the potential dose-dependent link between caffeine and endometriosis or the probable role of caffeine intake as a measurement of other unidentified biases.