Circulating Plasma Metabolites and Cognitive Function in a Puerto Rican Cohort

ENDOTHELIAL-DEPENDENT VASCULAR REACTIVITY AFTER CARDIOPULMONARY BYPASS IS ASSOCIATED WITH UNIQUE METABOLOMIC SIGNATURES

ABSTRACT

Cardiopulmonary bypass (CPB), an extracorporeal method necessary for the surgical correction of complex congenital heart defects, incites significant inflammation that affects vascular function. These changes are associated with alterations in cellular metabolism that promote energy production to deal with this stress. Utilizing laser Doppler perfusion monitoring coupled with iontophoresis in patients undergoing corrective heart surgery, we hypothesized that temporal, untargeted metabolomics could be performed to assess the link between metabolism and vascular function. Globally, we found 2,404 unique features in the plasma of patients undergoing CPB. Metabolites related to arginine biosynthesis were the most altered by CPB. Correlation of metabolic profiles with endothelial-dependent (acetylcholine [ACh]) or endothelial-independent (sodium nitroprusside [SNP]) vascular reactivity identified purine metabolism being most consistently associated with either vascular response. Concerning ACh-mediated responses, acetylcarnitine levels were most strongly associated, while glutamine levels were associated with both ACh and SNP responsiveness. These data provide insight into the metabolic landscape of children undergoing CPB for corrective heart surgery and provide detail into how these metabolites relate to physiological aberrations in vascular function.

Retinol intake and PCOS management: a plasma metabolite and protein analysis via Mendelian randomization and NHANES 2011-2016

Background

Polycystic Ovary Syndrome (PCOS) represents a complex endocrine disorder characterized by a significant interplay with metabolic dysfunction and obesity. This research endeavors to elucidate the causal dynamics among plasma metabolites, proteins, and PCOS, alongside Body Mass Index (BMI), to pinpoint prospective therapeutic interventions.

Methods

This investigation employed Mendelian randomization (MR) analyses combined with data derived from the National Health and Nutrition Examination Survey (NHANES) to explore the relationships between 1,400 plasma metabolites and PCOS, factoring in BMI adjustments. Additionally, the study examined the influence of plasma proteins and performed a retrospective cross-sectional analysis focusing on retinol consumption and testosterone levels.

Results

MR analyses showed metabolite Glycosyl-N-(2-hydroxynervonoyl)-sphingosine (GNS) and protein Keratin 19 (KRT19) were identified as significant markers in the context of PCOS and BMI adjustments. A Phenome-Wide Association Study (PheWAS) underscored the linkage between KRT19 and BMI, while gene-drug interaction findings demonstrated a connection between KRT19 and retinol. Analysis for NHANES data disclosed a negative correlation between retinol intake and testosterone levels, particularly within normal weight and obese cohorts, suggesting the feasibility of dietary interventions for PCOS management.

Conclusion

The study sheds light on the intricate interactions between plasma metabolites, proteins, and PCOS, considering BMI variations, and highlights KRT19 protein as a promising therapeutic target. The outcomes support the integration of retinol consumption into dietary strategies to regulate testosterone levels and potentially alleviate PCOS symptoms, underscoring the necessity for personalized nutritional and therapeutic approaches in the effective management of PCOS.

Blood metabolites, neurocognition and psychiatric disorders: a Mendelian randomization analysis to investigate causal pathways

BACKGROUND

Neurocognitive dysfunction is observationally associated with the risk of psychiatric disorders. Blood metabolites, which are readily accessible, may become highly promising biomarkers for brain disorders. However, the causal role of blood metabolites in neurocognitive function, and the biological pathways underlying their association with psychiatric disorders remain unclear.

METHODS

To explore their putative causalities, we conducted bidirectional two-sample Mendelian randomization (MR) using genetic variants associated with 317 human blood metabolites (nmax = 215,551), g-Factor (an integrated index of multiple neurocognitive tests with nmax = 332,050), and 10 different psychiatric disorders (n = 9,725 to 807,553) from the large-scale genome-wide association studies of European ancestry. Mediation analysis was used to assess the potential causal pathway among the candidate metabolite, neurocognitive trait and corresponding psychiatric disorder.

RESULTS

MR evidence indicated that genetically predicted acetylornithine was positively associated with g-Factor (0.035 standard deviation units increase in g-Factor per one standard deviation increase in acetylornithine level; 95% confidence interval, 0.021 to 0.049; P = 1.15 × 10-6). Genetically predicted butyrylcarnitine was negatively associated with g-Factor (0.028 standard deviation units decrease in g-Factor per one standard deviation increase in genetically proxied butyrylcarnitine; 95% confidence interval, -0.041 to -0.015; P = 1.31 × 10-5). There was no evidence of associations between genetically proxied g-Factor and metabolites. Furthermore, the mediation analysis via two-step MR revealed that the causal pathway from acetylornithine to bipolar disorder was partly mediated by g-Factor, with a mediated proportion of 37.1%. Besides, g-Factor mediated the causal pathway from butyrylcarnitine to schizophrenia, with a mediated proportion of 37.5%. Other neurocognitive traits from different sources provided consistent findings.

CONCLUSION

Our results provide genetic evidence that acetylornithine protects against bipolar disorder through neurocognitive abilities, while butyrylcarnitine has an adverse effect on schizophrenia through neurocognition. These findings may provide insight into interventions at the metabolic level for risk of neurocognitive and related disorders.

Carotenoid Supplementation for Alleviating the Symptoms of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by, among other things, dementia and a decline in cognitive performance. In AD, dementia has neurodegenerative features and starts with mild cognitive impairment (MCI). Research indicates that apoptosis and neuronal loss occur in AD, in which oxidative stress plays an important role. Therefore, reducing oxidative stress with antioxidants is a natural strategy to prevent and slow down the progression of AD. Carotenoids are natural pigments commonly found in fruits and vegetables. They include lipophilic carotenes, such as lycopene, α- and β-carotenes, and more polar xanthophylls, for example, lutein, zeaxanthin, canthaxanthin, and β-cryptoxanthin. Carotenoids can cross the blood-brain barrier (BBB) and scavenge free radicals, especially singlet oxygen, which helps prevent the peroxidation of lipids abundant in the brain. As a result, carotenoids have neuroprotective potential. Numerous in vivo and in vitro studies, as well as randomized controlled trials, have mostly confirmed that carotenoids can help prevent neurodegeneration and alleviate cognitive impairment in AD. While carotenoids have not been officially approved as an AD therapy, they are indicated in the diet recommended for AD, including the consumption of products rich in carotenoids. This review summarizes the latest research findings supporting the potential use of carotenoids in preventing and alleviating AD symptoms. A literature review suggests that a diet rich in carotenoids should be promoted to avoid cognitive decline in AD. One of the goals of the food industry should be to encourage the enrichment of food products with functional substances, such as carotenoids, which may reduce the risk of neurodegenerative diseases.

A principal component analysis of metabolome and cognitive decline among Japanese older adults: cross-sectional analysis using Tohoku Medical Megabank Cohort Study

BackgroundDementia is the leading cause of disability and imposes a significant burden on society. Previous studies have suggested an association between metabolites and cognitive decline. Although the metabolite composition differs between Western and Asian populations, studies targeting Asian populations remain scarce.MethodsThis cross-sectional study used data from a cohort survey of community-dwelling older adults aged ≥ 60 years living in Miyagi, Japan, conducted by Tohoku Medical Megabank Organization between 2013 and 2016. Forty-three metabolite variables quantified using nuclear magnetic resonance spectroscopy were used as explanatory variables. Dependent variable was the presence of cognitive decline (≤ 23 points), assessed by the Mini-Mental State Examination. Principal component (PC) analysis was performed to reduce the dimensionality of metabolite variables, followed by logistic regression analysis to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for cognitive decline.ResultsA total of 2,940 participants were included (men: 49.0%, mean age: 67.6 years). Among them, 1.9% showed cognitive decline. The first 12 PC components (PC1-PC12) accounted for 71.7% of the total variance. Multivariate analysis showed that PC1, which mainly represented essential amino acids, was associated with lower odds of cognitive decline (OR = 0.89; 95% CI, 0.80-0.98). PC2, which mainly included ketone bodies, was associated with cognitive decline (OR = 1.29; 95% CI, 1.11-1.51). PC3, which included amino acids, was associated with lower odds of cognitive decline (OR = 0.81; 95% CI, 0.66-0.99).ConclusionAmino acids are protectively associated with cognitive decline, whereas ketone metabolites are associated with higher odds of cognitive decline.

Large-Scale Population-Based Studies of Blood Metabolome and Brain Health

Metabolomics technologies enable the quantification of multiple metabolomic measures simultaneously, which provides novel insights into molecular aspects of human health and disease. In large-scale, population-based studies, blood is often the preferred biospecimen. Circulating metabolome may relate to brain health either by affecting or reflecting brain metabolism. Peripheral metabolites may act at or cross the blood-brain barrier and, subsequently, influence brain metabolism, or they may reflect brain metabolism if similar pathways are engaged. Peripheral metabolites may also include those penetrating the circulation from the brain, indicating, for example, brain damage. Most brain health-related metabolomics studies have been conducted in the context of neurodegenerative disorders and cognition, but some studies have also focused on neuroimaging markers of these disorders. Moreover, several metabolomics studies of neurodevelopmental disorders have been performed. Here, we provide a brief background on the types of blood metabolites commonly assessed, and we review the literature describing the relationships between human blood metabolome (n > 50 metabolites) and brain health reported in large-scale studies (n > 500 individuals).

Metabolites and MRI-Derived Markers of AD/ADRD Risk in a Puerto Rican Cohort

Objective

Several studies have examined metabolomic profiles in relation to Alzheimer's disease and related dementia (AD/ADRD) risk; however, few studies have focused on minorities, such as Latinos, or examined Magnetic-Resonance Imaging (MRI)-based outcomes.

Methods

We used multiple linear regression, adjusted for covariates, to examine the association between metabolite concentration and MRI-derived brain age deviation. Metabolites were measured at baseline with untargeted metabolomic profiling (Metabolon, Inc). Brain age deviation (BAD) was calculated at wave 4 (~ 9 years from Boston Puerto Rican Health Study (BPRHS) baseline) as chronologic age, minus MRI-estimated brain age, representing the rate of biological brain aging relative to chronologic age. We also examined if metabolites associated with BAD were similarly associated with hippocampal volume and global cognitive function at wave 4 in the BPRHS.

Results

Several metabolites, including isobutyrylcarnitine, propionylcarnitine, phenylacetylglutamine, phenylacetylcarnitine (acetylated peptides), p-cresol-glucuronide, phenylacetylglutamate, and trimethylamine N-oxide (TMAO) were inversely associated with brain age deviation. Taurocholate sulfate, a bile salt, was marginally associated with better brain aging. Most metabolites with negative associations with brain age deviation scores also were inversely associations with hippocampal volumes and wave 4 cognitive function.

Conclusion

The metabolites identifiedin this study are generally consistent with prior literature and highlight the role of BCAA, TMAO and microbially derived metabolites in cognitive decline.

Metabolites and Cognitive Decline in a Puerto Rican Cohort

Background

Recent studies have identified plasma metabolites associated with cognitive decline and Alzheimer's disease; however, little research on this topic has been conducted in Latinos, especially Puerto Ricans.

Objective

This study aims to add to the growing body of metabolomics research in Latinos to better understand and improve the health of this population.

Methods

We assessed the association between plasma metabolites and global cognition over 12 years of follow-up in 736 participants of the Boston Puerto Rican Health Study (BPRHS). Metabolites were measured with untargeted metabolomic profiling (Metabolon, Inc) at baseline. We used covariable adjusted linear mixed models (LMM) with a metabolite * time interaction term to identify metabolites (of 621 measured) associated with ∼12 years cognitive trajectory.

Results

We observed strong inverse associations between medium-chain fatty acids, caproic acid, and the dicarboxylic acids, azelaic and sebacic acid, and global cognition. N-formylphenylalanine, a tyrosine pathway metabolite, was associated with improvement in cognitive trajectory.

Conclusions

The metabolites identified in this study are generally consistent with prior literature and highlight a role medium chain fatty acid and tyrosine metabolism in cognitive decline.

Infant gut microbiota contributes to cognitive performance in mice

Gut microbiota has been linked to infant neurodevelopment. Here, an association between infant composite cognition and gut microbiota composition is established as soon as 6 months. Higher diversity and evenness characterize microbial communities of infants with composite cognition above (Inf-aboveCC) versus below (Inf-belowCC) median values. Metaproteomic and metabolomic analyses establish an association between microbial histidine ammonia lyase and infant histidine metabolome with cognition. Fecal transplantation from Inf-aboveCC versus Inf-belowCC donors into germ-free mice shows that memory, assessed by a novel object recognition test, is a transmissible trait. Furthermore, Inf-aboveCC mice are enriched in species belonging to Phocaeicola, as well as Bacteroides and Bifidobacterium, previously linked to cognition. Finally, Inf-aboveCC mice show lower fecal histidine and urocanate:histidine and urocanate:glutamate ratios in the perirhinal cortex compared to Inf-belowCC mice. Overall, these findings reveal a causative role of gut microbiota on infant cognition, pointing at the modulation of histidine metabolite levels as a potential underlying mechanism.

Proton Pump Inhibitor Use and Cognitive Function in the Boston Puerto Rican Health Study

BACKGROUND

There is a lack of consensus among studies on the association between proton pump inhibitor (PPI) use and cognitive impairment. This association is not well studied among minority populations, including among Puerto Ricans. Therefore, we sought to examine this association among Boston-area Puerto Ricans.

METHODS

The Boston Puerto Rican Health Study is an ongoing longitudinal cohort that enrolled 1499 Boston-area Puerto Rican adults, aged 45-75 years at baseline. Complete outcome and exposure data was available for 1290 baseline participants. Covariate-adjusted linear regression and linear mixed effects models were used to examine the association between PPI use, and global cognition, executive function, and memory cross-sectionally and longitudinally over ~12.7 years of follow-up. Furthermore, we examined the cross-sectional association between long-term PPI use (continuous use of ~6.2 years) and global cognition, executive function, and memory.

RESULTS

Among 1 290 participants at baseline, 313 (24.3%) self-reported PPI use. Baseline PPI use was not associated with baseline global cognition, executive function, or memory. Baseline PPI use also did not alter the trajectory of global cognition, executive function, or memory over ~12.7 years of follow-up. Long-term PPI use was not associated with global cognition, executive function, or memory over ~12.7 years of follow-up.

CONCLUSION

In this study of Boston-area Puerto Ricans, we did not observe an association between PPI use and global cognition, executive function, or memory either cross-sectionally or over 12.7 years of follow-up.

Improved psychosocial measures associated with physical activity may be explained by alterations in brain-gut microbiome signatures

Obesity contributes to physical comorbidities and mental health consequences. We explored whether physical activity could influence more than metabolic regulation and result in psychological benefits through the brain-gut microbiome (BGM) system in a population with high BMI. Fecal samples were obtained for 16 s rRNA profiling and fecal metabolomics, along with psychological and physical activity questionnaires. Whole brain resting-state functional MRI was acquired, and brain connectivity metrics were calculated. Higher physical activity was significantly associated with increased connectivity in inhibitory appetite control brain regions, while lower physical activity was associated with increased emotional regulation network connections. Higher physical activity was also associated with microbiome and metabolite signatures protective towards mental health and metabolic derangements. The greater resilience and coping, and lower levels of food addiction seen with higher physical activity, may be explained by BGM system differences. These novel findings provide an emphasis on the psychological and resilience benefits of physical activity, beyond metabolic regulation and these influences seem to be related to BGM interactions.

Dietary Responses of Dementia-Related Genes Encoding Metabolic Enzymes

The age-related loss of the cognitive function is a growing concern for global populations. Many factors that determine cognitive resilience or dementia also have metabolic functions. However, this duality is not universally appreciated when the action of that factor occurs in tissues external to the brain. Thus, we examined a set of genes involved in dementia, i.e., those related to vascular dementia, Alzheimer's disease, Parkinson's disease, and the human metabolism for activity in 12 metabolically active tissues. Mining the Genotype-Tissue Expression (GTEx) data showed that most of these metabolism-dementia (MD) genes (62 of 93, 67%) exhibit a higher median expression in any of the metabolically active tissues than in the brain. After identifying that several MD genes served as blood-based biomarkers of longevity in other studies, we examined the impact of the intake of food, nutrients, and other dietary factors on the expression of MD genes in whole blood in the Framingham Offspring Study (n = 2134). We observed positive correlations between flavonoids and HMOX1, taurine and UQCRC1, broccoli and SLC10A2, and myricetin and SLC9A8 (p < 2.09 × 10-4). In contrast, dairy protein, palmitic acid, and pie were negatively correlated, respectively, with the expression of IGF1R, CSF1R, and SLC9A8, among others (p < 2.92 × 10-4). The results of this investigation underscore the potential contributions of metabolic enzyme activity in non-brain tissues to the risk of dementia. Specific epidemiological or intervention studies could be designed using specific foods and nutrients or even dietary patterns focused on these foods and nutrients that influence the expression of some MD genes to verify the findings presented here.

Non-Enzymatic Antioxidants against Alzheimer's Disease: Prevention, Diagnosis and Therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. Although substantial research has been conducted to elucidate the complex pathophysiology of AD, the therapeutic approach still has limited efficacy in clinical practice. Oxidative stress (OS) has been established as an early driver of several age-related diseases, including neurodegeneration. In AD, increased levels of reactive oxygen species mediate neuronal lipid, protein, and nucleic acid peroxidation, mitochondrial dysfunction, synaptic damage, and inflammation. Thus, the identification of novel antioxidant molecules capable of detecting, preventing, and counteracting AD onset and progression is of the utmost importance. However, although several studies have been published, comprehensive and up-to-date overviews of the principal anti-AD agents harboring antioxidant properties remain scarce. In this narrative review, we summarize the role of vitamins, minerals, flavonoids, non-flavonoids, mitochondria-targeting molecules, organosulfur compounds, and carotenoids as non-enzymatic antioxidants with AD diagnostic, preventative, and therapeutic potential, thereby offering insights into the relationship between OS and neurodegeneration.

Differences between novel hybrid mode flaps and traditional perforator flaps at the level of metabolites using LC-MS

The multi-territory perforator flaps are widely used in plastic surgery. However, partial necrosis flap in the potential territory remains a challenge to plastic surgeons. We raised a novel "hybrid nourished mode" (HNM) flap based on the multi-territory deep inferior epigastric perforator (DIEP) flap to improve flap survival. Thirty-two rabbits were randomly divided into DIEP and HNM groups. Untargeted metabolic mechanisms between the DIEP and HNM groups were performed using LC-MS under the filter criteria of fold change >20.0 times or <0.05, and variable importance in projection (VIP) value was set at ≥1, P < 0.05. Between the two groups, flap survival, perfusion, microvasculature, histopathology, and immunohistochemistry of CD31 were assessed on post-operative day 7. We screened 16 different metabolites that mainly participated in biosynthesis of secondary metabolites, aminoacyl transfer RNA biosynthesis, phenylalanine metabolism, arginine and proline metabolism, among others. The results of the HNM flaps were higher than those of the DIEP flaps (P < 0.05) in the aspects of flap survival, flap perfusion, and microvasculature. Compared with the DIEP flaps, HNM has a stronger advantage in tissue metabolism. This study provided us with a better understanding and strong evidence in terms of metabolites on how HNM achieves the survival of large multi-territory perforator flaps.

Associations of the Lipidome with Ageing, Cognitive Decline and Exercise Behaviours

One of the most recognisable features of ageing is a decline in brain health and cognitive dysfunction, which is associated with perturbations to regular lipid homeostasis. Although ageing is the largest risk factor for several neurodegenerative diseases such as dementia, a loss in cognitive function is commonly observed in adults over the age of 65. Despite the prevalence of normal age-related cognitive decline, there is a lack of effective methods to improve the health of the ageing brain. In light of this, exercise has shown promise for positively influencing neurocognitive health and associated lipid profiles. This review summarises age-related changes in several lipid classes that are found in the brain, including fatty acyls, glycerolipids, phospholipids, sphingolipids and sterols, and explores the consequences of age-associated pathological cognitive decline on these lipid classes. Evidence of the positive effects of exercise on the affected lipid profiles are also discussed to highlight the potential for exercise to be used therapeutically to mitigate age-related changes to lipid metabolism and prevent cognitive decline in later life.

Metabolomic profiling of cerebrospinal fluid reveals an early diagnostic model for central nervous system involvement in acute lymphoblastic leukaemia

The pathogenesis of central nervous system involvement (CNSI) in patients with acute lymphoblastic leukaemia (ALL) remains unclear and a robust biomarker of early diagnosis is missing. An untargeted cerebrospinal fluid (CSF) metabolomics analysis was performed to identify independent risk biomarkers that could diagnose CNSI at the early stage. Thirty-three significantly altered metabolites between ALL patients with and without CNSI were identified, and a CNSI evaluation score (CES) was constructed to predict the risk of CNSI based on three independent risk factors (8-hydroxyguanosine, l-phenylalanine and hypoxanthine). This predictive model could diagnose CNSI with positive prediction values of 95.9% and 85.6% in the training and validation sets respectively. Moreover, CES score increased with the elevated level of central nervous system (CNSI) involvement. In addition, we validated this model by tracking the changes in CES at different stages of CNSI, including before CNSI and during CNSI, and in remission after CNSI. The CES showed good ability to predict the progress of CNSI. Finally, we constructed a nomogram to predict the risk of CNSI in clinical practice, which performed well compared with observed probability. This unique CSF metabolomics study may help us understand the pathogenesis of CNSI, diagnose CNSI at the early stage, and sequentially achieve personalized precision treatment.