Photoperiod effects on corticosterone and seasonal clocks in cafeteria-induced obese fischer 344 rats are influenced by gut microbiota.

Seasonal rhythms are gaining attention given their impact on metabolic disorders development such as obesity gut microbiota is emerging as a key factor in mediating this link. However, the underlying mechanisms are still poorly understood. In this regard, corticosterone may play a role as it has been shown to be affected by gut bacteria and seasonal rhythms, and has been linked to obesity. Thus, this study aimed to investigate if seasonal rhythms effects on corticosterone are influenced by gut microbiota in obese rats and whether this may be related to seasonal and clock genes expression in the pituitary gland and colon. Fischer 344 male rats fed with cafeteria diet (CAF) were housed under different photoperiods for 9 weeks and treated with an antibiotic cocktail (ABX) in drinking water during the last 4 weeks. Rats fed with standard chow and CAF-fed rats without ABX were included as controls. ABX altered gut microbiota, corticosterone levels and seasonal clock expression in the pituitary depending on photoperiod conditions. These results suggest a link between gut bacteria, seasonal rhythms and corticosterone and a novel nutrigenomic target for obesity.

Time-of-Day Adrenal Modulation of Corticosterone Synthesis is Affected by Sex and Diet but Not by Proanthocyanidins in Rat.

SCOPE: The aim of this study is to investigate the effect of time-of-day on serum hormones and gene expression in adrenal glands, studying the impact of sex, obesogenic diet, and timing of proanthocyanidins administration, with a focus on glucocorticoids synthesis by this gland. METHODS AND RESULTS: Female and male rats, assigned to a standard chow or a cafeteria diet-fed group, receive a daily oral dose of a grape seed proanthocyanidin extract (GSPE), or a vehicle (when light is turned on, or when light is turned off). Corticosterone, estradiol, and testosterone serum levels, and the expression analysis of clock genes and genes related to corticosterone synthesis pathway, are assessed. Serum hormone levels exhibited a marked time-of-day effect also see in the expression of scavenger receptor class B member 1 (Scarb1) and cyp11b genes. The correlation between these two genes and period circadian regulator 2 (Per2) is also extended to other clock genes, although to a lesser extent: cryptochrome (Cry) and nuclear receptor subfamily 1 group D member 1 (Rev-erba). CONCLUSION: The strong correlations found suggest an important role of local Per2 (but also of Cry and Rev-erbA) in regulating the expression of the enzymes involved in the corticosterone synthesis pathway. The expression of clock genes in adrenals is influenced by sex and diet but not by GSPE.

Sex Differences in the Absorption, Disposition, Metabolism, and Excretion of Grape Seed Proanthocyanidins in Prepubescent Rats.

SCOPE: The absorption, disposition, metabolism, and excretion (ADME) of phenolic compounds are key factors in determining their bioactivity. The group demonstrates that the ADME of a Grape Seed Proanthocyanidin Extract (GSPE) depends on sex in adult rats and specifically, methylated metabolites are only quantified in brain male adult rats. The aim of this study is to determine whether these differences exist before puberty. METHODS AND RESULTS: Prepubescent 4-week-old male and female Wistar rats are administered GSPE at a dose of 1000 mg kg-1. Plasma, liver, mesenteric white adipose tissue (MWAT), brain, and kidneys are extracted excised 2 h after GSPE administration, and the PAs metabolite profile is studied by HPLC-ESI-MS/MS. Moreover, plasma estradiol and brain and liver catechol-O-methyltransferase (COMT) protein levels are also studied. Results showed that there are no differences in plasma and brain among sexes and only differences are observed in liver, MWAT, and kidney with individual metabolites. This agrees with the lack of differences in estradiol and COMT levels among sexes. However, the ADME of PAs metabolites is higher in male rats. CONCLUSIONS: The results demonstrate lack of sex-dependence in metabolite profile in prepubescent rats, suggesting that sex differences in the metabolism of GSPE occur due to puberty.

Grape Seed Proanthocyanidin Extract Attenuates Cafeteria-Diet-Induced Liver Metabolic Disturbances in Rats: Influence of Photoperiod.

This study investigated the influence of photoperiod (day length) on the efficacy of grape seed proanthocyanidin extract (GSPE) in mitigating metabolic disorders in obese rats fed a cafeteria diet. Rats were exposed to standard (L12), long (L18), or short (L6) photoperiods and treated with GSPE or vehicle. In the standard photoperiod, GSPE reduced body weight gain (50.5%), total cholesterol (37%), and triglycerides (34.8%), while increasing the expression of hepatic metabolic genes. In the long photoperiod, GSPE tended to decrease body weight gain, increased testosterone levels (68.3%), decreased liver weight (12.4%), and decreased reverse serum amino acids. In the short photoperiod, GSPE reduced glycemia (~10%) and lowered triglyceride levels (38.5%), with effects modified by diet. The standard photoperiod showed the greatest efficacy against metabolic syndrome-associated diseases. The study showed how day length affects GSPE's benefits and underscores considering biological rhythms in metabolic disease therapies.

Administration time effect of dietary proanthocyanidins on the metabolome of Fischer 344 rats is sex- and diet-dependent.

Proanthocyanidins (PAs) are one of the most commonly ingested polyphenols in the human diet, with a wide range of beneficial health effects. Remarkably, PAs have been reported to influence core and peripheral clock genes expression, and their effects may change in a time-of-day dependent manner. Therefore, the aim of this study was to investigate whether the capacity of PAs to modulate the metabolome is conditioned by the time-of-day in which these compounds are consumed in a diet- and sex-dependent manner. To do this, a grape seed proanthocyanidin extract (GSPE) was administered to female and male Fischer 344 rats at ZT0 (in the morning) and ZT12 (at night) and the GSPE administration time effect was evaluated on clock genes expression, melatonin hormone and serum metabolite levels in a healthy and obesogenic context. The results showed an administration time effect of GSPE on the metabolome in a sex and diet-dependent manner. Specifically, there was an effect on amino acid, lipid and cholate metabolite levels that correlated with the central clock genes expression. Therefore, this study shows a strong influence of sex and diet on the PAs effects on the metabolome, modulated in turn by the time-of-day.

Gut Microbiota Influences the Photoperiod Effects on Proanthocyanidins Bioavailability in Diet-Induced Obese Rats.

SCOPE: Polyphenols health effects on obesity are mainly attributed to their metabolites generated after their gastrointestinal digestion, in which gut microbiota plays an important role. Moreover, gut microbiota composition and polyphenols bioavailability are influenced by differences in day light length (photoperiod). Thus, this study evaluates if a grape seed proanthocyanidins (GSPEs) extract bioavailability is influenced by different photoperiod exposure via gut microbiota modulation in an obesogenic context. METHODS AND RESULTS: Cafeteria diet-induced obese Fischer 344 rats are housed under different photoperiod conditions (6, 12, or 18 h of light per day) during 9 weeks and administered with GSPE (25 mg kg-1 ) or GSPE and an antibiotic cocktail (ABX) for the last 4 weeks. Serum GSPE-derived metabolites are quantified by HPLC-MS/MS. CONCLUSION: A higher bioavailability is observed under 6 h light/18 h darkness (L6) compared to 18 h light/6 h darkness (L18). Individual metabolites, especially those from the gut microbiota, are affected by photoperiods. ABX treatment alters these photoperiod-mediated changes. Therefore, these results suggest that gut microbiota plays a key role in the photoperiod effects on GSPE bioavailability in obese rats.

Grape-Seed Proanthocyanidins Modulate Adipose Tissue Adaptations to Obesity in a Photoperiod-Dependent Manner in Fischer 344 Rats.

Seasonal rhythms drive metabolic adaptations that influence body weight and adiposity. Adipose tissue is a key regulator of energy homeostasis in the organism, and its healthiness is needed to prevent the major consequences of overweight and obesity. In this context, supplementation with proanthocyanidins has been postulated as a potential strategy to prevent the alterations caused by obesity. Moreover, the effects of these (poly)phenols on metabolism are photoperiod dependent. In order to describe the impact of grape-seed proanthocyanidins extract (GSPE) on important markers of adipose tissue functionality under an obesogenic environment, we exposed Fischer 344 rats to three different photoperiods and fed them a cafeteria diet for five weeks. Afterwards, we supplemented them with 25 mg GSPE/kg/day for four weeks. Our results revealed that GSPE supplementation prevented excessive body weight gain under a long photoperiod, which could be explained by increased lipolysis in the adipose tissue. Moreover, cholesterol and non-esterified fatty acids (NEFAs) serum concentrations were restored by GSPE under standard photoperiod. GSPE consumption slightly helped combat the obesity-induced hypertrophy in adipocytes, and adiponectin mRNA levels were upregulated under all photoperiods. Overall, the administration of GSPE helped reduce the impact of obesity in the adipose tissue, depending on the photoperiod at which GSPE was consumed and on the type of adipose depots.

Photoperiod Conditions Modulate Serum Oxylipins Levels in Healthy and Obese Rats: Impact of Proanthocyanidins and Gut Microbiota.

Seasonal rhythms are emerging as a key factor influencing gut microbiota and bioactive compounds functionality as well as several physiological processes such as inflammation. In this regard, their impact on the modulation of oxylipins (OXLs), which are important lipid mediators of inflammatory processes, has not been investigated yet. Hence, we aimed to investigate the effects of photoperiods on OXLs metabolites in healthy and obesogenic conditions. Moreover, we evaluated if the impact of proanthocyanidins and gut microbiota on OXLs metabolism is influenced by photoperiod in obesity. To this purpose, Fischer 344 rats were housed under different photoperiod conditions (L6: 6 h light, L12: 12 h light or L18:18 h light) and fed either a standard chow diet (STD) or a cafeteria diet (CAF) for 9 weeks. During the last 4 weeks, obese rats were daily administered with an antibiotic cocktail (ABX), an oral dose of a grape seed proanthocyanidin extract (GSPE), or with their combination. CAF feeding and ABX treatment affected OXLs in a photoperiod dependent-manner. GSPE significantly altered prostaglandin E2 (PGE2) levels, only under L6 and mitigated ABX-mediated effects only under L18. In conclusion, photoperiods affect OXLs levels influenced by gut microbiota. This is the first time that the effects of photoperiod on OXLs metabolites have been demonstrated.

Organic vs. Non-Organic Plant-Based Foods-A Comparative Study on Phenolic Content and Antioxidant Capacity.

A plant's stress response involves the production of phytochemicals, including phenolic compounds. Their synthesis can be modulated by organic (ORG) or non-organic (NORG) farming systems in which they are grown. To examine this issue, thirteen plant-based foods cultivated in ORG and NORG systems were compared in terms of antioxidant capacity, total content of phenolics, anthocyanins, flavan-3-ols and flavonols. The results showed that NORG fruits tended to have higher phenolic compounds content, whereas ORG fruits had more antioxidant capacity. NORG legume stood out for having higher values from all the parameters analyzed in comparison to its ORG equivalent. ORG nuts showed more flavan-3-ols and flavonols than their NORG counterparts, nonetheless, tended to be less antioxidant. ORG vegetables displayed higher phenolics and anthocyanins, which reflected in higher antioxidant capacity than NORG ones. These findings suggest that farming systems differentially modulate phenolic compound composition and antioxidant capacity based on the plant species studied.

Fatty acid metabolism in liver and muscle is strongly modulated by photoperiod in Fischer 344 rats.

Circadian and seasonal variations produce variations in physiological processes throughout the day and the year, respectively. In this sense, both the light and the moment of feeding are strong modulators of the central and peripheral clocks. However, little is known about its influence on certain metabolic parameters and on the composition of liver and muscle fatty acids (FA). In the present study, 24 Fischer 344 rats were exposed for 11 weeks to different photoperiods, L6, L12 and L18, with 6, 12 and 18 h of light/day, respectively. They were fed a standard diet. Serum metabolic parameters, gene expression of liver enzymes and gastrocnemius muscle involved in the synthesis, elongation, desaturation and ß-oxidation of FA were analyzed. We have found that exposure to different hours of light has a clear effect on FA composition and gene expression in the liver. Mainly, the biosynthesis of unsaturated FA was altered in the L18 animals with respect to those exposed to L12, while the L6 did not show significant changes. At the muscle level, differences were observed in the concentration of mono and polyunsaturated FA. A multivariate analysis confirmed the differences between L12 and L18 in a significant way. We conclude that exposure to long days produces changes in the composition of liver and muscle FA, as well as changes in the gene expression of oxidative enzymes compared to exposure to L12, which could be a consequence of different seasonal eating patterns.

Do You Have Problems When Reproducing Bioactivities of Food or Food Components? The Importance of Biological Rhythms.

With the onset of omics sciences, in the 20th century, nutritional studies evolved to investigate the effects of diet at a molecular level, giving rise to nutritional genomics, which includes both nutrigenomics and nutrigenetics [...].

Grape Seed Proanthocyanidins Modulate the Hepatic Molecular Clock via MicroRNAs.

SCOPE: Circadian rhythm is an endogenous and self-sustained timing system, responsible for the coordination of daily processes in 24-h timescale. It is regulated by an endogenous molecular clock, which is sensitive to external cues as light and food. This study has previously shown that grape seed proanthocyanidins extract (GSPE) regulates the hepatic molecular clock. Moreover, GSPE is known to interact with some microRNAs (miRNAs). Therefore, the aim of this study is to evaluate if the activity of GSPE as modulator of hepatic clock genes can be mediated by miRNAs. METHODS AND RESULTS: 250 mg kg-1 of GSPE is administered to Wistar rats before a 6-h jet lag and sacrificed at different time points. GSPE modulated both expression of Bmal1 and miR-27b-3p in the liver. Cosinor-based analysis reveals that both Bmal1 and miR-27b-3p expression follow a circadian rhythm, a negative interaction between them, and the role of GSPE adjusting the hepatic peripheral clock via miRNA. Additionally, in vitro studies show that Bmal1 is sensitive to GSPE (25 mg L-1 ). However, this effect is independent of miR-27b-3p. CONCLUSION: miRNA regulation of peripheral clocks via GSPE may be part of a complex mechanism that involves the crosstalk with the central system rather than a direct effect.

The effects of grape seed proanthocyanidins in cafeteria diet-induced obese Fischer 344 rats are influenced by faecal microbiota in a photoperiod dependent manner.

Polyphenols are of high interest due to their beneficial health effects, including anti-obesity properties. The gut microbiota may play an important role in polyphenol-mediated effects as these bacteria are significantly involved in the metabolism of polyphenols. Moreover, seasonal rhythms have been demonstrated to influence both the gut microbiota composition and polyphenol bioavailability. Thus, the goal of this study was to evaluate the impact of photoperiods and microbiota on polyphenol functionality in an obesogenic context. Towards this aim, cafeteria diet-fed Fischer 344 rats were housed under three different photoperiod conditions (L6: 6 h of light, L12: 12 h of light and L18: 18 h of light) for 9 weeks. During the last 4 weeks of the experiment, rats were daily administered with an oral dose of a grape seed proanthocyanidin extract (GSPE) (25 mg per kg body weight). Additionally, rats treated with GSPE and an antibiotic cocktail (ABX) in their drinking water were included for a better understanding of the gut microbiota role in GSPE functionality. Vehicle and non-ABX treated rats were included as controls. GSPE decreased body weight gain and fat depots only under L18 conditions. Interestingly, the gut microbiota composition was strongly altered in this photoperiod. GSPE + ABX-treated rats gained significantly less body weight compared to the rats of the rest of the treatments under L18 conditions. These results suggest that GSPE functionality is modulated by the gut microbiota in a photoperiod dependent manner. These novel findings corroborate seasonal rhythms as key factors that must be taken into account when investigating the effects of polyphenols in the treatment or prevention of chronic diseases.

Impact of Seasonal Consumption of Local Tomatoes on the Metabolism and Absorption of (Poly)Phenols in Fischer Rats.

Consuming (poly)phenol-rich fruits and vegetables, including tomato, is associated with health benefits. The health effects of tomato (poly)phenolic compounds have been attributed to their metabolites rather than parent compounds and their bioavailability can be modulated by several factors. This study aimed to evaluate the effect of seasonal consumption of local tomatoes on their (poly)phenol bioavailability. For this, (poly)phenol absorption and metabolism were evaluated by ultra-high-performance liquid chromatography coupled with mass spectrometry and linear ion trap mass spectrometric (uHPLC-MSn) after chronic tomato consumption in Fischer rats exposed to three photoperiods mimicking the seasonal daylight schedule. Tomatoes from two locations in Spain (LT, local tomatoes and NLT, non-local tomatoes) were used in this in vivo feeding study. The bioavailability of tomato (poly)phenols depended on the photoperiod to which the rats were exposed, the metabolite concentrations significantly varying between seasons. In-season tomato consumption allowed obtaining the highest concentration of total circulating metabolites. In addition, the origin of the tomato administered generated marked differences in the metabolic profiles, with higher serum concentrations reached upon NLT ingestion. We concluded that in-season tomato consumption led to an increase in (poly)phenol circulation, whereas LT consumption showed lower circulating metabolites than NLT ones. Thus, the origin of the tomato and the seasonal daylight schedule affect the bioavailability of tomato (poly)phenols, which could also affect their bioactivity.

Systematic analysis of nutrigenomic effects of polyphenols related to cardiometabolic health in humans - Evidence from untargeted mRNA and miRNA studies.

Cardiovascular and metabolic disorders present major causes of mortality in the ageing population. Polyphenols present in human diets possess cardiometabolic protective properties, however their underlying molecular mechanisms in humans are still not well identified. Even though preclinical and in vitro studies advocate that these bioactives can modulate gene expression, most studies were performed using targeted approaches. With the objective to decipher the molecular mechanisms underlying polyphenols cardiometabolic preventive properties in humans, we performed integrative multi-omic bioinformatic analyses of published studies which reported improvements of cardiometabolic risk factors following polyphenol intake, together with genomic analyses performed using untargeted approach. We identified 5 studies within our criteria and nearly 5000 differentially expressed genes, both mRNAs and miRNAs, in peripheral blood cells. Integrative bioinformatic analyses (e.g. pathway and gene network analyses, identification of transcription factors, correlation of gene expression profiles with those associated with diseases and drug intake) revealed that these genes are involved in the processes such as cell adhesion and mobility, immune system, metabolism, or cell signaling. We also identified 27 miRNAs known to regulate processes such as cell cytoskeleton, chemotaxis, cell signaling, or cell metabolism. Gene expression profiles negatively correlated with expression profiles of cardiovascular disease patients, while a positive correlation was observed with gene expression profiles following intake of drugs against cardiometabolic disorders. These analyses further advocate for health protective effects of these bioactives against age-associated diseases. In conclusion, polyphenols can exert multi-genomic modifications in humans and use of untargeted methods coupled with bioinformatic analyses represent the best approach to decipher molecular mechanisms underlying healthy-ageing effects of these bioactives.

(Poly)phenolic composition of tomatoes from different growing locations and their absorption in rats: A comparative study.

The aim of this work was to address whether the growing location of tomato could generate a different (poly)phenol profile able to affect both in vivo absorption and (poly)phenol metabolite pattern upon tomato consumption. uHPLC-MSn analyses allowed to obtain a detailed (poly)phenol profile of tomatoes from two locations in Spain, quantifying 57 (poly)phenolic compounds. However, local and non-local tomatoes showed a different concentration of their native (poly)phenols, which could be attributed to diverse cultivation origin. Rat serum was analysed after an acute tomato feeding. Seven phenolic metabolites were quantified through uHPLC-MSn. Pharmacokinetic parameters were further evaluated, revealing different serum concentrations of (poly)phenolic metabolites between tomatoes. The maximum peak serum concentrations, reached mainly after 2 h after ingestion, led to suppose that serum metabolites were mostly derived from absorption in the upper gastrointestinal tract. The growing location of tomatoes affected both the content of native (poly)phenols and their in vivo absorption.

Cardioprotective Properties of Phenolic Compounds: A Role for Biological Rhythms.

Cardiovascular diseases (CVD) are the leading cause of deaths worldwide and their prevalence is continuously increasing. Available treatments may present several side effects and therefore the development of new safer therapeutics is of interest. Phenolic compounds have shown several cardioprotective properties helpful in reducing different CVD risk factors such as inflammation, elevated blood pressure, hyperlipidemia, or endothelial dysfunction. These factors are significantly influenced by biological rhythms which are in fact emerging as key modulators of important metabolic and physiological processes. Thus, increased events of CVD have been observed under circadian rhythm disruption or in winter versus other seasons. These rhythms can also affect the functionality of phenolic compounds. Indeed, different effects have been observed depending on the administration time or under different photoperiods. Therefore, in this review the focus will be on the potential of phenolic compounds as therapeutics to prevent CVD via biological rhythm modulation.

Gut Seasons: Photoperiod Effects on Fecal Microbiota in Healthy and Cafeteria-Induced Obese Fisher 344 Rats.

Gut microbiota and biological rhythms are emerging as key factors in the modulation of several physiological and metabolic processes. However, little is known about their interaction and how this may affect host physiology and metabolism. Several studies have shown oscillations of gut microbiota that follows a circadian rhythmicity, but, in contrast, variations due to seasonal rhythms have not been sufficiently investigated yet. Thus, the goal of this study was to investigate the impact of different photoperiods, which mimic seasonal changes, on fecal microbiota composition and how this interaction affects diet-induced obesity development. To this aim, Fisher 344 male rats were housed under three photoperiods (L6, L12 and L18) and fed with standard chow diet or cafeteria diet (CAF) for 9 weeks. The 16S ribosomal sequencing of collected fecal samples was performed. The photoperiod exposure significantly altered the fecal microbiota composition under L18, especially in CAF-fed rats. Moreover, these alterations were associated with changes in body weight gain and different fat parameters. These findings suggest a clear impact of seasonal rhythms on gut microbiota, which ultimately translates into different susceptibilities to diet-induced obesity development. This is the first time to our knowledge that the photoperiod impact on gut microbiota composition has been described in an obesity context although further studies are needed in order to elucidate the mechanisms involved.

Administration Time Significantly Affects Plasma Bioavailability of Grape Seed Proanthocyanidins Extract in Healthy and Obese Fischer 344 Rats.

SCOPE: Phenolic compounds are bioactive molecules that are associated with several health benefits. Metabolization and absorption are the main determinants of their bioavailability and bioactivity. Thus, the study of the factors that modulate these processes, such as sex or diet is essential. Recently, it has been shown that biological rhythms may also play a key role. Hence, the aim of this study is to evaluate if the bioavailability of a grape proanthocyanidin extract (GSPE) is affected by the administration time in an animal model of metabolic syndrome (MetS). METHODS AND RESULTS: Female and male Fischer 344 rats are fed either a standard or a cafeteria diet (CAF) for 9 weeks, and an oral dose of GSPE (25 mg kg-1 ) is daily administered either at 8:00 am (zeitgeber time (ZT)-0) or at 8:00 pm (ZT-12) during the last 4 weeks. Plasma phenolic compounds are then quantified by liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Phase-II and gut microbiota-derived phenolic metabolites are affected by ZT in all conditions or only in obese rats, respectively. CAF feeding affected the bioavailability of phenolic acids and free flavan-3-ols. Differences due to sex are also observed. CONCLUSION: These findings demonstrate that ZT, diet, and sex are key factors influencing phenolic compounds bioavailability.

In-Season Consumption of Locally Produced Tomatoes Decreases Cardiovascular Risk Indices.

Tomatoes are widely consumed worldwide at any time of the year. However, depending on the variety, they have a characteristic season. We evaluated the consequences metabolic of consumption of Ekstasis tomatoes from different geographical origin and in different seasons in Fischer 344 rats. The hepatic gene expression of key enzymes in lipid metabolism was also evaluated. Animals were classified in three photoperiods (L6, L12, and L18) and in three treatments (vehicle: VH; local tomato: LT; and non-local tomato: nLT). We measured serum metabolic parameters and the gene expression of liver enzymes related to lipid metabolism (Acc1, Cpt1a, Had, Fas1, Srebp-1c, Fatp5, Cd36). LT consumption in season decreased cardiovascular risk 1 and coefficient atherogenic by 1.81 (p = 0.031) and in L6 decreased TAG and glucose (p = 0.046; p = 0.024). The L18-LT animals had decreased total cholesterol (p = 0.029) and gene expression of Srebp1-c (p = 0.022) but increased expression of Acc1 (p = 0.032). The treatments significantly affected the expression of Acc1 and Fas1 in the liver and the levels of serum TAG and glucose. A significant effect of photoperiod on serum concentration of glucose, insulin, HOMA index, and on the hepatic expression of Srep1-c, Fas1, and Acc1 was observed.