RESUMO
Vascular dysfunction: develops progressively with ageing; increases the risk of cardiovascular diseases (CVD); and is characterized by endothelial dysfunction and arterial stiffening, which are primarily mediated by superoxide-driven oxidative stress and consequently reduced nitric oxide (NO) bioavailability and arterial structural changes. Interventions initiated before vascular dysfunction manifests may have more promise for reducing CVD risk than interventions targeting established dysfunction. Gut microbiome-derived trimethylamine N-oxide (TMAO) induces vascular dysfunction, is associated with higher CV risk, and can be suppressed by 3,3-dimethyl-1-butanol (DMB). We investigated whether DMB supplementation could prevent age-related vascular dysfunction in C57BL/6N mice when initiated prior to development of dysfunction. Mice received drinking water with 1% DMB or normal drinking water (control) from midlife (18 months) until being studied at 21, 24 or 27 months of age, and were compared to young adult (5 month) mice. Endothelial function [carotid artery endothelium-dependent dilatation (EDD) to acetylcholine; pressure myography] progressively declined with age in control mice, which was fully prevented by DMB via higher NO-mediated EDD and lower superoxide-related suppression of EDD (normalization of EDD with the superoxide dismutase mimetic TEMPOL). In vivo aortic stiffness (pulse wave velocity) increased progressively with age in controls, but DMB attenuated stiffening by â¼ 70%, probably due to preservation of endothelial function, as DMB did not affect aortic intrinsic mechanical (structural) stiffness (stress-strain testing) nor adventitial abundance of the arterial structural protein collagen. Our findings indicate that long-term DMB supplementation prevents/attenuates age-related vascular dysfunction, and therefore has potential for translation to humans for reducing CV risk with ageing. KEY POINTS: Vascular dysfunction, characterized by endothelial dysfunction and arterial stiffening, develops progressively with ageing and increases the risk of cardiovascular diseases (CVD). Interventions aimed at preventing the development of CV risk factors have more potential for preventing CVD relative to those aimed at reversing established dysfunction. The gut microbiome-derived metabolite trimethylamine N-oxide (TMAO) induces vascular dysfunction, is associated with higher CV risk and can be suppressed by supplementation with 3,3-dimethyl-1-butanol (DMB). In mice, DMB prevented the development of endothelial dysfunction and delayed and attenuated in vivo arterial stiffening with ageing when supplementation was initiated in midlife, prior to the development of dysfunction. DMB supplementation or other TMAO-suppressing interventions have potential for translation to humans for reducing CV risk with ageing.
Assuntos
Doenças Cardiovasculares , Água Potável , Doenças Vasculares , Rigidez Vascular , Camundongos , Humanos , Animais , Superóxidos/metabolismo , Vasodilatação , Análise de Onda de Pulso , Endotélio Vascular/metabolismo , Butanóis/metabolismo , Água Potável/metabolismo , Camundongos Endogâmicos C57BL , Envelhecimento/metabolismo , Doenças Vasculares/metabolismo , Óxido Nítrico/metabolismoRESUMO
Type 2 diabetes (T2D) is characterized by hyperglycemia and insulin resistance. Cocoa may slow T2D development and progression. This study employed male and female BTBR.Cg-Lepob/ob/WiscJ (ob/ob) and wild type (WT) controls to assess the potential for cocoa to ameliorate progressive T2D and compare responses between sexes. Mice received diet without (WT, ob/ob) or with cocoa extract (ob/ob + c) for 10 weeks. Acute cocoa reduced fasting hyperglycemia in females, but not males, after 2 weeks. Chronic cocoa supplementation (6-10 weeks) ameliorated hyperinsulinemia in males and worsened hyperlipidemia and hyperinsulinemia in females, yet also preserved and enhanced beta cell survival in females. The underlying mechanisms of these differences warrant further study. If sex differences are apparent in subsequent preclinical studies, clinical studies will be warranted to establish whether these differences are relevant in humans. Sex differences may need to be considered when designing human dietary interventions for T2D.
Assuntos
Cacau , Diabetes Mellitus Tipo 2 , Hiperglicemia , Hiperinsulinismo , Animais , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Humanos , Masculino , Camundongos , Obesidade , Projetos Piloto , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêuticoRESUMO
Flavanols are metabolized by the gut microbiota to bioavailable metabolites, and the absorbed fraction is excreted primarily via urine. Uroepithelial cells are thus a potential site of activity due to exposure to high concentrations of these compounds. Chemoprevention by flavanols may be partly due to these metabolites. In Vitro work in this area relies on a limited pool of commercially available microbial metabolites, and little has been done in bladder cancer. The impact of physiologically relevant mixtures of flavanols and their metabolites remains unknown. Rats were fed various flavanols and urine samples, approximating the bioavailable metabolome, were collected. Urines were profiled by UPLC-MS/MS, and their anti-proliferative activities were assayed In Vitro in four bladder cancer models. Significant interindividual variability was observed for composition and proliferation. Microbial metabolite concentrations (valerolactones, phenylalkyl acids and hippuric acids) were positively associated with reduced bladder cancer proliferation In Vitro, while native flavanols were poorly correlated with activity. These results suggest that microbial metabolites may be responsible for chemoprevention in uroepithelial cells following flavanol consumption. This highlights the potential to use individual genetics and microbial metabotyping to design personalized dietary interventions for cancer prevention and/or adjuvant therapy to reduce bladder cancer incidence and improve outcomes.
Assuntos
Microbioma Gastrointestinal , Neoplasias da Bexiga Urinária , Animais , Cromatografia Líquida , Polifenóis/análise , Ratos , Espectrometria de Massas em Tandem , Neoplasias da Bexiga Urinária/tratamento farmacológicoRESUMO
Grape pomace (GP) management has been a challenge worldwide. We have previously demonstrated a biorefinery process to recover oil and polyphenols, and produce biofuels from GP sequentially, although over 50% of GP solid waste remains post-processing. To approach zero solid waste during GP processing, herein a pyrolysis process was designed for converting GP and its secondary processing wastes to biochars, which were then evaluated for lead (Pb) adsorption from water. GP lignin pyrolyzed at 700 °C (GPL2700 biochar) with specific surface area of 485 m2/g showed the highest Pb adsorption capacity, and achieved 66.5% of Pb removal from an initially high concentration of 300 mg/L within 30 min. At low initial Pb concentrations (50-3000 µg/L), GPL2700 biochar could reduce Pb concentrations to 0.208-77.2 µg/L. In addition, experimental and modeling results revealed that both physisorption and chemisorption mechanisms were involved in the adsorption process of GPL2700 biochar.
Assuntos
Vitis , Água , Adsorção , Carvão Vegetal , Chumbo , Águas ResiduáriasRESUMO
Bitterness and astringency (dryness) are characteristic sensory attributes of flavanol-rich foods. The degree of polymerization (DP) of flavanols influences their bitter and astringent sensations. Smaller DP compounds can enter the papillae on the tongue, eliciting a bitter response. Larger DP compounds are sterically inhibited from entering papillae and instead interact with oral proteins, cause precipitation, and elicit astringent sensations. Previous research has indicated that bitterness preference is related to health status, density of fungiform papillae on the tongue, and sensitivity to bitter compounds such as 6-n-propyl-thiouracil (PROP). The purpose of this study was to examine trends in liking, bitterness intensity, and astringency intensity of wine-like products with flavanols of different DP using a consumer sensory panel. Participants (nâ¯=â¯102) were segmented by phenotypes: body fat percentage (BF%), body mass index (BMI), PROP sensitivity, and stated bitter food preference. Differences in wine liking, perceived bitterness intensity, and astringency intensity were observed between three model wine samples of varying flavanol mean degrees of polymerization (mDP, i.e. the average size (polymer length) of flavanol compounds in a mixture). Specifically, with increased mDP, overall liking and bitterness liking decreased, with concurrent increased perception of bitterness and astringency intensity. Greater differences between phenotypes were observed when participants were segmented by BF% and BMI classification, than when segmented by PROP sensitivity classification. Reduced ability to detect differences in bitterness and astringency were noted in participants of higher weight status. Overall, these data suggest that weight status in adults is a greater predictor of liking of flavanol-rich foods than bitterness sensitivity (as determined by PROP classification), and that reduced perception of bitterness and astringency associated with weight gain may impact selection and preference for these foods.
Assuntos
Composição Corporal/fisiologia , Preferências Alimentares/efeitos dos fármacos , Polifenóis/administração & dosagem , Paladar/efeitos dos fármacos , Vinho/análise , Tecido Adiposo , Adulto , Índice de Massa Corporal , Peso Corporal/fisiologia , Feminino , Preferências Alimentares/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Polimerização , Propiltiouracila/administração & dosagem , Paladar/fisiologia , Papilas Gustativas/efeitos dos fármacos , Limiar Gustativo/efeitos dos fármacos , Adulto JovemRESUMO
KEY POINTS: Age-related arterial dysfunction, characterized by oxidative stress- and inflammation-mediated endothelial dysfunction and arterial stiffening, is the primary risk factor for cardiovascular diseases. To investigate whether age-related changes in the gut microbiome may mediate arterial dysfunction, we suppressed gut microbiota in young and old mice with a cocktail of broad-spectrum, poorly-absorbed antibiotics in drinking water for 3-4 weeks. In old mice, antibiotic treatment reversed endothelial dysfunction and arterial stiffening and attenuated vascular oxidative stress and inflammation. To provide insight into age-related changes in gut microbiota that may underlie these observations, we show that ageing altered the abundance of microbial taxa associated with gut dysbiosis and increased plasma levels of the adverse gut-derived metabolite trimethylamine N-oxide. The results of the present study provide the first proof-of-concept evidence that the gut microbiome is an important mediator of age-related arterial dysfunction and therefore may be a promising therapeutic target for preserving arterial function with ageing, thereby reducing the risk of cardiovascular diseases. ABSTRACT: Oxidative stress-mediated arterial dysfunction (e.g. endothelial dysfunction and large elastic artery stiffening) is the primary mechanism driving age-related cardiovascular diseases. Accumulating evidence suggests the gut microbiome modulates host physiology because dysregulation ('gut dysbiosis') has systemic consequences, including promotion of oxidative stress. The present study aimed to determine whether the gut microbiome modulates arterial function with ageing. We measured arterial function in young and older mice after 3-4 weeks of treatment with broad-spectrum, poorly-absorbed antibiotics to suppress the gut microbiome. To identify potential mechanistic links between the gut microbiome and age-related arterial dysfunction, we sequenced microbiota from young and older mice and measured plasma levels of the adverse gut-derived metabolite trimethylamine N-oxide (TMAO). In old mice, antibiotics reversed endothelial dysfunction [area-under-the-curve carotid artery dilatation to acetylcholine in young: 345 ± 16 AU vs. old control (OC): 220 ± 34 AU, P < 0.01; vs. old antibiotic-treated (OA): 334 ± 15 AU; P < 0.01 vs. OC] and arterial stiffening (aortic pulse wave velocity in young: 3.62 ± 0.15 m s-1 vs. OC: 4.43 ± 0.38 m s-1 ; vs. OA: 3.52 ± 0.35 m s-1 ; P = 0.03). These improvements were accompanied by lower oxidative stress and greater antioxidant enzyme expression. Ageing altered the abundance of gut microbial taxa associated with gut dysbiosis. Lastly, plasma TMAO was higher with ageing (young: 2.6 ± 0.4 µmol L-1 vs. OC: 7.2 ± 2.0 µmol L-1 ; P < 0.0001) and suppressed by antibiotic treatment (OA: 1.2 ± 0.2 µmol L-1 ; P < 0.0001 vs. OC). The results of the present study provide the first evidence for the gut microbiome being an important mediator of age-related arterial dysfunction and oxidative stress and suggest that therapeutic strategies targeting gut microbiome health may hold promise for preserving arterial function and reducing cardiovascular risk with ageing in humans.
Assuntos
Envelhecimento/fisiologia , Antibacterianos/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Rigidez Vascular/efeitos dos fármacos , Envelhecimento/patologia , Animais , Artérias Carótidas/crescimento & desenvolvimento , Artérias Carótidas/metabolismo , Artérias Carótidas/fisiologia , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiologia , Masculino , Metilaminas/sangue , Camundongos , Camundongos Endogâmicos C57BL , Vasodilatação/efeitos dos fármacosRESUMO
Background: Objective indicators of dietary intake (e.g., biomarkers) are needed to overcome the limitations of self-reported dietary intake assessment methods in adolescents. To our knowledge, no controlled feeding studies to date have evaluated the validity of urinary sodium, nitrogen, or sugar excretion as dietary biomarkers in adolescents.Objective: This investigation aimed to evaluate the validity of urinary sodium, nitrogen, and total sugars (TS) excretion as biomarkers for sodium, protein, and added sugars (AS) intake in nonobese adolescents.Methods: In a crossover controlled feeding study design, 33 adolescents [12-18 y of age, 47 ± 25th percentile (mean ± SD) of body mass index (BMI; in kg/m2) for age] consumed 5% AS [low added sugars (LAS)] and 25% AS [high added sugars (HAS)] isocaloric, macronutrient-matched (55% carbohydrate, 30% fat, and 15% protein) diets for 7 d each, in a randomly assigned order, with a 4-wk washout period between diets. On the final 2 d of each diet period, 24-h urine samples were collected. Thirty-two adolescents completed all measurements (97% retention).Results: Urinary sodium was not different from the expected 90% recovery (mean ± SD: 88% ± 18%, P = 0.50). Urinary nitrogen was correlated with protein intake (r = 0.69, P < 0.001), although it was below the 80% expected recovery (62% ± 7%, P < 0.001). Urinary TS values were correlated with AS intake during the HAS diet (r = 0.77, P < 0.001) and had a higher R2 value of 0.28 than did AS intake (R2 = 0.36). TS excretion differed between LAS (0.226 ± 0.09 mg/d) and HAS (0.365 ± 0.16 mg/d) feeding periods (P < 0.001).Conclusions: Urinary sodium appears to be a valid biomarker for sodium intake in nonobese adolescents. Urinary nitrogen is associated with protein intake, but nitrogen excretion rates were less than previously reported for adults, possibly owing to adolescent growth rates. TS excretion reflects AS at 25% AS intake and was responsive to the change in AS intake. Thus, urinary biomarkers are promising objective indicators of dietary intake in adolescents, although larger-scale feeding trials are needed to confirm these findings. This trial was registered at clinicaltrials.gov as NCT02455388.
Assuntos
Carboidratos/urina , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Nitrogênio/urina , Sódio na Dieta/administração & dosagem , Sódio/urina , Adolescente , Biomarcadores , Criança , Estudos Cross-Over , Feminino , Humanos , MasculinoRESUMO
BACKGROUND: Three-fourths of adults older than 55 years in the United States are overweight or obese. Prebiotics including inulin-type fructans may benefit with weight management. AIM: We aimed to investigate the acute effects of pre-meal inulin consumption on energy intake (EI) and appetite in older adults. METHODS: Sedentary, overweight or obese middle-aged and older adults ( n = 7, 60.9 ± 4.4 years, BMI 32.9 ± 4.3 kg/m2) ingested inulin (10 g) or a water preload before each test period in a randomly assigned order. EI, appetite and gastrointestinal symptoms were monitored during the following 24 h. RESULTS: No differences in EI were noted between conditions (inulin: 14744 ± 5552 kJ, control: 13924 ± 4904 kJ, p > 0.05). Rumbling was increased with inulin consumption ( p < 0.05). CONCLUSION: Pre-meal inulin consumption does not acutely decrease EI or suppress appetite in older adults. Further research should address individual differences among diets, eating behaviors, and microbiota profiles.
Assuntos
Ingestão de Energia , Inulina/administração & dosagem , Obesidade/tratamento farmacológico , Sobrepeso/tratamento farmacológico , Idoso , Apetite , Índice de Massa Corporal , Estudos Cross-Over , Método Duplo-Cego , Exercício Físico , Feminino , Humanos , Masculino , Refeições , Pessoa de Meia-Idade , Projetos PilotoRESUMO
Gut microbes play a pivotal role in host physiology by producing beneficial or detrimental metabolites. Gut bacteria metabolize dietary choline and L-carnitine to trimethylamine (TMA) which is then converted to trimethylamine-N-oxide (TMAO). An elevated circulating TMAO is associated with diabetes, obesity, cardiovascular disease, and cancer in humans. In the present study, we investigated the effect of dietary blueberries and strawberries at a nutritional dosage on TMA/TMAO production and the possible role of gut microbes. Blueberry cohort mice received a control (C) or freeze-dried blueberry supplemented (CB) diet for 12 weeks and subgroups received an antibiotics cocktail (CA and CBA). Strawberry cohort mice received a control (N) or strawberry-supplemented (NS) diet and subgroups received antibiotics (NA and NSA). Metabolic parameters, choline, TMA, and TMAO were assessed in addition to microbial profiling and characterization of berry powders. Blueberry supplementation (equivalent to 1.5 human servings) reduced circulating TMAO in CB versus C mice (~48%) without changing choline or TMA. This effect was not mediated through alterations in metabolic parameters. Dietary strawberries did not reduce choline, TMA, or TMAO. Depleting gut microbes with antibiotics in these cohorts drastically reduced TMA and TMAO to not-quantified levels. Further, dietary blueberries increased the abundance of bacterial taxa that are negatively associated with circulating TMA/TMAO suggesting the role of gut microbes. Our phenolic profiling indicates that this effect could be due to chlorogenic acid and increased phenolic contents in blueberries. Our study provides evidence for considering dietary blueberries to reduce TMAO and prevent TMAO-induced complications.
Assuntos
Mirtilos Azuis (Planta) , Microbioma Gastrointestinal , Metilaminas , Humanos , Camundongos , Animais , Mirtilos Azuis (Planta)/metabolismo , Camundongos Endogâmicos CBA , Colina/metabolismo , Antibacterianos/farmacologiaRESUMO
SCOPE: A study is conducted to determine the anti-inflammatory effects of cocoa and polyphenol-rich cocoa fractions in the dextran sulfate sodium (DSS)-induced mouse model of acute colonic inflammation. METHODS AND RESULTS: Male C57BL/6J mice are treated with dietary cocoa powder, an extractable cocoa polyphenol fraction, or a non-extractable cocoa polyphenol fraction for 2 weeks prior to treatment with 2.5% DSS in the drinking water for 7 days to induce colonic inflammation. Cocoa treatment continues during the DSS period. Cocoa and/or cocoa fractions exacerbate DSS-induced weight loss and fail to mitigate DSS-induced colon shortening but do improve splenomegaly. Cocoa/cocoa fraction treatment fails to mitigate DSS-induced mRNA and protein markers of inflammation. Principal component analysis shows overlap between cocoa or cocoa fraction-treated mice and DSS-induced controls, but separation from mice not treated with DSS. CONCLUSION: The results suggest cocoa and cocoa polyphenols may not be useful in mitigating acute colonic inflammation.
Assuntos
Cacau , Colite , Colo , Sulfato de Dextrana , Camundongos Endogâmicos C57BL , Polifenóis , Animais , Masculino , Polifenóis/farmacologia , Polifenóis/análise , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/dietoterapia , Cacau/química , Colo/efeitos dos fármacos , Colo/patologia , Colo/metabolismo , Camundongos , Modelos Animais de Doenças , Anti-Inflamatórios/farmacologia , Inflamação/tratamento farmacológicoRESUMO
SCOPE: Gut microbiota depletion using antibiotics in drinking water is a valuable tool to investigate the role of gut microbes and microbial metabolites in health and disease. However, there are challenges associated with this model. Animals avoid drinking water because of the antibiotic bitterness, which affects their metabolic health. The present study develops an efficient strategy to deplete gut microbes without affecting metabolic parameters. METHODS AND RESULTS: Male C57BL/6J mice (7 weeks old) are fed a control (C) or high-fat (HF) diet. Subgroups of C and HF mice receive an antibiotic cocktail in drinking water (CA and HA). The antibiotic dosage is gradually increased so that the animals adapt to the taste of antibiotics. Metabolic parameters, gut microbiome, and microbial metabolites are assessed after 12 weeks treatment. Culture methods and 16s rRNA amplification confirm the depletion of gut microbes in antibiotic groups (CA and HA). Further, antibiotic treatment does not alter metabolic parameters (body weight, body fat, lean body mass, blood glucose, and glucose/insulin tolerance), whereas it suppresses the production of diet-derived microbial metabolites (trimethylamine and trimethylamine-N-oxide). CONCLUSION: This strategy effectively depletes gut microbes and suppresses the production of microbial metabolites in mice without affecting their metabolic health.
Assuntos
Água Potável , Microbioma Gastrointestinal , Metilaminas , Masculino , Camundongos , Animais , Antibacterianos/farmacologia , RNA Ribossômico 16S/genética , Camundongos Endogâmicos C57BL , Dieta Hiperlipídica/efeitos adversosRESUMO
High circulating levels of trimethylamine N-oxide (TMAO) have been associated with cardiovascular disease risk. TMAO is formed through a microbiome-host pathway utilizing primarily dietary choline as a substrate. Specific gut microbiota transform choline into trimethylamine (TMA), and, when absorbed, host hepatic flavin-containing monooxygenase 3 (FMO3) oxidizes TMA into TMAO. Chlorogenic acid and its metabolites reduce microbial TMA production in vitro. However, little is known regarding the potential for chlorogenic acid and its bioavailable metabolites to inhibit the last step: hepatic conversion of TMA to TMAO. We developed a screening methodology to study FMO3-catalyzed production of TMAO from TMA. HepG2 cells were unable to oxidize TMA into TMAO due to their lack of FMO3 expression. Although Hepa-1 cells did express FMO3 when pretreated with TMA and NADPH, they lacked enzymatic activity to produce TMAO. Rat hepatic microsomes contained active FMO3. Optimal reaction conditions were: 50 µM TMA, 0.2 mM NADPH, and 33 µL microsomes/mL reaction. Methimazole (a known FMO3 competitive substrate) at 200 µM effectively reduced FMO3-catalyzed conversion of TMA to TMAO. However, bioavailable chlorogenic acid metabolites did not generally inhibit FMO3 at physiological (1 µM) nor supra-physiological (50 µM) doses. Thus, the effects of chlorogenic acid in regulating TMAO levels in vivo are unlikely to occur through direct FMO3 enzyme inhibition. Potential effects on FMO3 expression remain unknown. Intestinal inhibition of TMA production and/or absorption are thus likely their primary mechanisms of action.
Assuntos
Microssomos Hepáticos , Oxigenases de Função Mista , Ratos , Animais , Microssomos Hepáticos/metabolismo , Ácido Clorogênico , NADP , Fenóis , Colina/metabolismoRESUMO
Dietary flavanols are known for disease preventative properties but are often poorly absorbed. Gut microbiome flavanol metabolites are more bioavailable and may exert protective activities. Using metabolite mixtures extracted from the urine of rats supplemented with flavanols and treated with or without antibiotics, we investigated their effects on INS-1 832/13 ß-cell glucose stimulated insulin secretion (GSIS) capacity. We measured insulin secretion under non-stimulatory (low) and stimulatory (high) glucose levels, insulin secretion fold induction, and total insulin content. We conducted treatment-level comparisons, individual-level dose responses, and a responder vs. non-responder predictive analysis of metabolite composition. While the first two analyses did not elucidate treatment effects, metabolites from 9 of the 28 animals demonstrated significant dose responses, regardless of treatment. Differentiation of responders vs. non-responder revealed that levels of native flavanols and valerolactones approached significance for predicting enhanced GSIS, regardless of treatment. Although treatment-level patterns were not discernable, we conclude that the high inter-individual variability shows that metabolite bioactivity on GSIS capacity is less related to flavanol supplementation or antibiotic treatment and may be more associated with the unique microbiome or metabolome of each animal. These findings suggest flavanol metabolite activities are individualized and point to the need for personalized nutrition practices.
RESUMO
The balance of putative pro- and antiinflammatory lipoxygenase (LOX)-derived S-hydroxyeicosatetraenoic acids (S-HETEs) in colon mucosa is a potential target for modulating colon cancer risk and progression. The biological effects of S-HETEs and R-hydroxyeicosatetraenoic acids (produced by distinct pathways) may differ, but levels of these compounds in the colon are unknown. The objective of this study was to develop chiral methods to characterize hydroxyeicosatetraenoic (HETE) enantiomers in colonic mucosa and evaluate the effects of fish oil on HETE formation. C57BL/6 mice (COX-1 null, COX-2 null, wild-type) were fed a diet supplemented with either olive oil or menhaden oil for 11 wk, and R-/S-HETEs in colonic mucosa were quantified by chiral LC-MS/MS. The R-enantiomer comprised 60-72% of 5-HETE, 18-58% of 15-HETE, and 1-16% of 12-HETE in colonic mucosa, suggesting that non-LOX sources contribute to HETE profiles. Fish oil reduced levels of both R- and S-HETEs, and increased the preponderance of the R-enantiomers (particularly 12- and 15-HETEs). There was apparent shunting of arachidonic acid to 12-/15-LOX in the COX-1 null animals. This is the first report of the enantiomeric composition of HETEs in the colon in vivo and shows large effects of fish oil in the normal colon.
Assuntos
Ácido 12-Hidroxi-5,8,10,14-Eicosatetraenoico/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Colo/efeitos dos fármacos , Óleos de Peixe/farmacologia , Ácidos Hidroxieicosatetraenoicos/metabolismo , Mucosa Intestinal/efeitos dos fármacos , Ácido 12-Hidroxi-5,8,10,14-Eicosatetraenoico/análise , Ácido 12-Hidroxi-5,8,10,14-Eicosatetraenoico/química , Animais , Colo/metabolismo , Ciclo-Oxigenase 1/genética , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Feminino , Ácidos Hidroxieicosatetraenoicos/análise , Ácidos Hidroxieicosatetraenoicos/química , Mucosa Intestinal/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , EstereoisomerismoRESUMO
The production of pro-atherogenic trimethylamine N-oxide (TMAO) is dependent on the gut microbiota metabolism of quaternary amines (i.e., choline) into trimethylamine (TMA). Nutritional strategies that target microbial conversion of choline into TMA could reduce cardiovascular disease and atherosclerosis burden by reducing subsequent formation of TMAO. This study aimed to evaluate (1) whether beverages rich in known inhibitors of TMA production (chlorogenic acid, catechin and epicatechin) can reduce TMA formation and (2) the effect of upper gastrointestinal digestion on efficacy. To do this, either raw or digested coffee, tea and cocoa beverages were evaluated for their TMA-d9 production inhibition in our ex vivo-in vitro fermentation model with human fecal slurries and choline-d9 substrate. Results showed that digestion was required to unlock the TMA-d9 production inhibition potential of coffee and cocoa beverages, and that teas did not possess a strong inhibition potential either digested or undigested. By fractionating digested bioactive beverages, we determined that those fractions rich in chlorogenic acid were the most bioactive. Overall, this study suggests that regular cocoa and coffee consumption could be a nutritional strategy able to reduce TMAO levels. In vivo studies should be carried out to confirm the potential of these beverages as strategies to inhibit TMA production.
Assuntos
Aterosclerose , Café , Aterosclerose/metabolismo , Bactérias/metabolismo , Bebidas , Ácido Clorogênico , Colina/metabolismo , Fermentação , Humanos , Metilaminas/metabolismoRESUMO
Trimethylamine N-oxide (TMAO) is a pro-atherosclerotic product of dietary choline metabolism generated by a microbiome-host axis. The first step in this pathway is the enzymatic metabolism of choline to trimethylamine (TMA) by the gut microbiota. This reaction could be targeted to reduce atherosclerosis risk. We aimed to evaluate potential inhibitory effects of select dietary phenolics and their relevant gut microbial metabolites on TMA production via a human ex vivo-in vitro fermentation model. Various phenolics inhibited choline use and TMA production. The most bioactive compounds tested (caffeic acid, catechin, and epicatechin) reduced TMA-d9 formation (compared to control) by 57.5 ± 1.3 to 72.5 ± 0.4% at 8 h and preserved remaining choline-d9 concentrations by 194.1 ± 6.4 to 256.1 ± 6.3% at 8 h. These inhibitory effects were achieved without altering cell respiration or cell growth. However, inhibitory effects decreased at late fermentation times, which suggested that these compounds delay choline metabolism rather than completely inhibiting TMA formation. Overall, caffeic acid, catechin, and epicatechin were the most effective noncytotoxic inhibitors of choline use and TMA production. Thus, these compounds are proposed as lead bioactives to test in vivo.
Assuntos
Microbioma Gastrointestinal , Colina/metabolismo , Fermentação , Ensaios de Triagem em Larga Escala , Humanos , MetilaminasRESUMO
Phenolic rich 100% grape juice has been associated with many health benefits, but its place in dietary guidance is controversial relative to whole fruit. Direct comparisons of phenolic profiles and bioavailability between these food forms are needed. Phenolic bioaccessibility and metabolism from Concord (CG) and Niagara (NG) grapes and corresponding 100% juices were investigated using an in vitro digestion coupled with anaerobic gut fermentation model. Intestinal transport of resulting bioaccessible phenolics and microbial metabolites was estimated using a Caco-2 cell model. Total bioaccessible phenolics from both upper and lower digestion were similar (P > 0.05) between NG (400.9 ± 26.3 µmol per 100 g) and NGJ (349.5 ± 8.3 µmol per 100 g) and significantly different (P < 0.05) between CG (417.2 ± 24.4 µmol per 100 g) and CGJ (294.3 ± 45.4 µmol per 100 g) total cellular transport of phenolics was similar (P > 0.05) between whole grapes (89.4 ± 5.3 µmol per 100 g for CG, and 71.8 ± 2.4 µmol per 100 g for NG) and 100% juices (88.0 ± 5.6 µmol per 100 g for CGJ, and 85.3 ± 9.4 µmol per 100 g for NGJ). Differences were observed between the location of phenolic metabolism, bioaccessibility and subsequent cellular transport of individual phenolics between grapes and juice matrices. Specifically, greater amounts of phenolics were transported from grape juices than whole grapes from the upper tract. However, cumulative bioaccessibility and transport from upper and lower GI digestion/fermentation together indicates that the absorbable phenolics from 100% grape juice is similar to that of whole grapes, suggesting that phenolic-mediated health benefits from consumption of whole fruit and juice may be similar.
Assuntos
Microbioma Gastrointestinal , Vitis , Células CACO-2 , Digestão , Fermentação , Frutas/química , Humanos , Fenóis/análise , Vitis/metabolismoRESUMO
Age-related cognitive changes can be the first indication of the progression to dementias, such as Alzheimer's disease. These changes may be driven by a complex interaction of factors including diet, activity levels, genetics, and environment. Here we review the evidence supporting relationships between flavonoids, physical activity, and brain function. Recent in vivo experiments and human clinical trials have shown that flavonoid-rich foods can inhibit neuroinflammation and enhance cognitive performance. Improved cognition has also been correlated with a physically active lifestyle, and with the functionality and diversity of the gut microbiome. The great majority (+ 90%) of dietary flavonoids are biotransformed into phytoactive phenolic metabolites at the gut microbiome level prior to absorption, and these prebiotic flavonoids modulate microbiota profiles and diversity. Health-relevant outcomes from flavonoid ingestion may only be realized in the presence of a robust microbiome. Moderate-to-vigorous physical activity (MVPA) accelerates the catabolism and uptake of these gut-derived anti-inflammatory and immunomodulatory metabolites into circulation. The gut microbiome exerts a profound influence on cognitive function; moderate exercise and flavonoid intake influence cognitive benefits; and exercise and flavonoid intake influence the microbiome. We conclude that there is a potential for combined impacts of flavonoid intake and physical exertion on cognitive function, as modulated by the gut microbiome, and that the combination of a flavonoid-rich diet and routine aerobic exercise may potentiate cognitive benefits and reduce cognitive decline in an aging population, via mechanisms mediated by the gut microbiome. Mechanistic animal studies and human clinical interventions are needed to further explore this hypothesis.
RESUMO
Insights into food matrix factors impacting bioavailability of bioactive carotenoids and chlorophylls from fruits and vegetable ingredients are essential to understanding their ability to promote health. The stability and bioaccessibility of carotenoids and chlorophylls were assessed from dehydrated, spray-dried, freeze-dried and fresh spinach ingredient forms using in vitro models simulating upper gastrointestinal (GI) digestion and lower GI anaerobic fecal fermentation. Intestinal transport of bioaccessible bioactives from both upper and lower GI compartments was assessed using the Caco-2 human intestinal cell model. Differences in carotenoid and chlorophyll contents were observed between ingredient forms and these influenced bioaccessibility. Lower carotenoid and chlorophyll contents in spray dried spinach resulted in the lowest total bioaccessible content among all spinach treatments (5.8 ± 0.2 µmoles per g DW carotenoid and chlorophyll). The total bioaccessible content was statistically similar between freeze-dried (12.5 ± 0.6 µmoles per g DW), dehydrated (12.5 ± 3.2 µmoles per g DW), and fresh spinach (14.2 ± 1.2 µmoles per g DW). Post anaerobic fermentation, cellular accumulation of carotenoids was higher (17.57-19.52 vs. 5.11-8.56%), while that of chlorophylls was lower (3.05-5.27 vs. 5.25-6.44%), compared to those observed following upper GI digestion. Collectively, these data suggest that spinach forms created by various drying technologies deliver similar levels of bioaccessible spinach bioactives and that the lower GI tract may serve as a site for significant absorption fostered by interactions with gut microbial communities that liberate additional bioactives from the spinach matrix.
Assuntos
Carotenoides , Spinacia oleracea , Anaerobiose , Células CACO-2 , Carotenoides/metabolismo , Clorofila , Digestão , Fermentação , Promoção da Saúde , Humanos , Pós , Spinacia oleracea/metabolismoRESUMO
Obesity causes inflammation which may lead to development of co-morbidities like cardiovascular diseases. Cocoa is a popular food ingredient that has been shown to mitigate obesity and inflammation in preclinical models. Cocoa typically undergoes fermentation and roasting prior to consumption, which can affect the polyphenol content in cocoa. The aim of this study was to compare the effect of fermentation and roasting protocols on the ability of cocoa to mitigate obesity, gut barrier dysfunction, and chronic inflammation in high fat (HF)-fed, obese C57BL/6J mice. We found that treatment of mice with 80 mg/g dietary cocoa powder for 8 weeks reduced rate of body weight gain in both male and female mice (46-57%), regardless of fermentation and roasting protocol. Colonic length was increased (11-24%) and gut permeability was reduced (48-79%) by cocoa supplementation. Analysis of the cecal microbiome showed that cocoa, regardless of fermentation and roasting protocol, reduced the ratio of Firmicutes to Bacteroidetes. Multivariate statistical analysis of markers of inflammation and body weight data showed sex differences in the effect of both the HF diet as well as cocoa supplementation. Based on this data there was strong protective efficacy from cocoa supplementation especially for the more processed cocoa samples. Overall, this study shows that anti-obesity and anti-inflammatory efficacy of cocoa is resilient to changes in polyphenol content and composition induced by fermentation or roasting. Further, this study shows that although cocoa has beneficial effects in both males and females, there are significant sex differences.