Plasma thiobarbituric acid reactive substances (TBARS) in young adults: Obesity increases fasting levels only in men whereas glucose ingestion, and not protein or lipid intake, increases postprandial concentrations regardless of sex and obesity

Obesity and polycystic ovary syndrome influence on intestinal permeability at fasting, and modify the effect of diverse macronutrients on the gut barrier

Women with the extremely prevalent polycystic ovary syndromegather multiple cardiovascular risk factors and chronic subclinical inflammation. Interactions between diet, adiposity, and gut microbiota modulate intestinal permeabilityand bacterial product translocation, and may contribute to the chronic inflammation process associated with the polycystic ovary syndrome. In the present study, we aimed to address the effects of obesity, functional hyperandrogenism, and diverse oral macronutrients on intestinal permeabilityby measuring circulating markers of gut barrier dysfunction and endotoxemia. Participants included 17 non-hyperandrogenic control women, 17 women with polycystic ovary syndrome, and 19 men that were submitted to glucose, lipid, and protein oral loads. Lipopolysaccharide-binding protein, plasma soluble CD14, succinate, zonulin family peptide, and glucagon-like peptide-2 were determined at fasting and after oral challenges. Macronutrient challenges induced diverse changes on circulating intestinal permeabilitybiomarkers in the acute postprancial period, with lipids and proteins showing the most unfavorable and favorable effects, respectively. Particularly, lipopolysaccharide-binding protein, zonulin family peptide, and glucagon-like peptide-2 responses were deregulated by the presence of obesity after glucose and lipid challenges. Obese subjects showed higher fasting intestinal permeabilitybiomarkers levels than non-obese individuals, except for plasma soluble CD14. The polycystic ovary syndromeexacerbated the effect of obesity further increasing fasting glucagon-like peptide-2, lipopolysaccharide-binding protein, and succinate concentrations. We observed specific interactions of the polycystic ovary syndromewith obesity in the postprandial response of succinate, zonulin family peptide, and glucagon-like peptide-2. In summary, obesity and polycystic ovary syndromemodify the effect of diverse macronutrients on the gut barrier, and alsoinfluence intestinal permeabilityat fasting,contributing to the morbidity of functional hyperandrogenism by inducing endotoxemia and subclinical chronic inflammation.

Serum metabolomics profiling by proton nuclear magnetic resonance spectrometry of the response to single oral macronutrient challenges in women with polycystic ovary syndrome (PCOS) compared with male and female controls

BACKGROUND

The polycystic ovary syndrome (PCOS) is associated with insulin resistance, obesity and cardiometabolic comorbidities. We here challenged the hypothesis, using state-of-the-art proton nuclear magnetic resonance spectrometry (1H-NMRS) metabolomics profiling, that androgen excess in women induces a certain masculinization of postprandial metabolism that is modulated by obesity.

MATERIALS AND METHODS

Participants were 53 Caucasian young adults, including 17 women with classic PCOS consisting of hyperandrogenism and ovulatory dysfunction, 17 non-hyperandrogenic women presenting with regular menses, and 19 healthy men, selected to be similar in terms of age and body mass index (BMI). Half of the subjects had obesity. Patients were submitted to isocaloric separate glucose, lipid and protein oral challenges in alternate days and fasting and postprandial serum samples were submitted to 1H-NMRS metabolomics profiling for quantification of 36 low-molecular-weight polar metabolites.

RESULTS

The largest postprandial changes were observed after glucose and protein intake, with lipid ingestion inducing smaller differences. Changes after glucose intake consisted of a marked increase in carbohydrates and byproducts of glycolysis, and an overall decrease in byproducts of proteolysis, lipolysis and ketogenesis. After the protein load, most amino acids and derivatives increased markedly, in parallel to an increase in pyruvate and a decrease in 3-hydroxybutyric acid and glycerol. Obesity increased β- and D-glucose and pyruvate levels, with this effect being observed mostly after glucose ingestion in women with PCOS. Regardless of the type of macronutrient, men presented increased lysine and decreased 3-hydroxybutyric acid. In addition, non-obese men showed increased postprandial β-glucose and decreased pyroglutamic acid, compared with non-obese control women. We observed a common pattern of postprandial changes in branched-chain and aromatic amino acids, where men showed greater amino acids increases after protein intake than control women and patients with PCOS but only within the non-obese participants. Conversely, this increase was blunted in obese men but not in obese women, who even presented a larger increase in some amino acids compared with their non-obese counterparts. Interestingly, regardless of the type of macronutrient, only obese women with PCOS showed increased leucine, lysine, phenylalanine and tryptophan levels compared with non-obese patients.

CONCLUSIONS

Serum 1H-NMRS metabolomics profiling indicated sexual dimorphism in the responses to oral macronutrient challenges, which were apparently driven by the central role of postprandial insulin effects with obesity, and to a lesser extent PCOS, exerting modifying roles derived from insulin resistance. Hence, obesity impaired metabolic flexibility in young adults, yet sex and sex hormones also influenced the regulation of postprandial metabolism.

Serum metabolomics profiling by proton nuclear magnetic resonance spectroscopy reveals sexual dimorphism and masculinization of intermediate metabolism in women with polycystic ovary syndrome (PCOS)

BACKGROUND

The polycystic ovary syndrome (PCOS) is associated with insulin resistance, obesity and cardiometabolic comorbidities. We here challenged the hypothesis, using state-of-the art proton nuclear magnetic resonance spectroscopy metabolomics profiling, that androgen excess in women induces also a certain masculinization of intermediate metabolism that is modulated by obesity.

METHODS

Participants were 53 Caucasian young adults, including 17 women with classic PCOS consisting of hyperandrogenism and ovulatory dysfunction, 17 non-hyperandrogenic women presenting with regular menses, and 19 healthy men, selected in order to be similar in terms of age and body mass index (BMI). Half of the subjects had obesity defined by a body mass index ≥ 30 kg/m². Subjects maintained the same diet unrestricted in carbohydrates for 3 days before sampling and maintained their lifestyle and exercise patterns prior and during the study. Plasma samples were submitted to proton nuclear magnetic resonance spectroscopy metabolomics profiling.

RESULTS

Obesity associated a metabolomics profile mainly characterized by increased branched chain and aromatic aminoacids. Regardless of obesity, this unfavorable profile also characterized men as compared with control women, and was shared by women with PCOS. Notably, the negative impact of obesity on metabolomics profile was restricted to women, with obese men showing no further deterioration when compared with their non-obese counterparts.

CONCLUSIONS

Serum metabolomics profiling by proton nuclear magnetic resonance spectroscopy reveals sexual dimorphism, and masculinization of intermediate metabolism in women with PCOS, further suggesting a role for sex and sex hormones in the regulation of intermediate metabolism.

The Effect of 75 Grams of Glucose during OGTT on Plasma Markers of Lipid and Lipoprotein Peroxidation, Oxidized LDL and Thiobarbituric Acid Reactive Substances, in People with Increased Body Mass

Obesity, currently defined as a disease, is associated with a number of metabolic disorders, and oxidative stress is discussed as the link between them. The aim of this study was to analyze the plasma markers reflecting oxidative modification of lipids and lipoproteins, oxidized LDL (oxLDL) and thiobarbituric acid reactive substances (TBARS), under the influence of the 75 g of oral glucose during oral glucose tolerance test (OGTT), in patients with increased body mass. One hundred twenty individuals of both genders (46 women and 74 men) aged 26 to 75 years with increased body mass (BMI > 25 kg/m2) were recruited for the study. OGTT was performed in each of the qualified persons, and glycemia, insulinemia, and concentrations of oxLDL and TBARS were measured fasting and at 120 min of OGTT. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to assess the degree of insulin resistance (IR). In order to assess the changes of the investigated parameters under the influence of 75 g glucose, the index ROGTT = [120’]/[0’] was calculated to obtain oxLDL-ROGTT and TBARS-ROGTT. The statistical analysis was performed in the entire study population and subsequent groups from H1 to H4, defined by HOMA-IR quartiles. In the entire study population and the subgroups, oxidative stress markers changed during OGTT. From H1 to H4 group, increasing oxLDL and TBARS were observed both in the fasting state and at 120 min of OGTT, and the oxLDL-ROGTT index decreased from the H2 to the H4 group. The intensification of IR in people with increased body mass may predispose them to enhanced oxidative modification of lipoproteins. Individual reduction in the concentration of oxLDL during OGTT, in reference to fasting value (decreased oxLDL-ROGTT), suggests increased uptake of modified lipoproteins by scavenger receptor-presenting cells or increased migration to the vascular wall.

Postprandial Metabolic and Oxidative Stress Responses to Grape Pomace Extract in Healthy Normal and Overweight/Obese Women: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

Postprandial oxidative stress has been shown to promote atherosclerosis. Grape pomace (GP) is a source of similar-to-wine bioactive micro-constituents with known antioxidant properties. The aim of the present study was to evaluate metabolic and oxidative stress responses after the intake of grape pomace (GP) extract along with a high-fat meal, in normal and overweight healthy women. In a randomized, double-blind, placebo-controlled crossover study, 18 women were finally included, 11 with BMI < 25 kg/m2 and 7 with BMI > 25 kg/m2, and consumed a high-fat meal with placebo or GP extract capsules in two separate visits. Blood samples were collected before and 6 h after the consumption. Measurements included basic biochemical markers, uric acid (UA), protein carbonyls (PC), thiobarbituric acid substance (TBARS) levels, as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. At certain time points, the GP extract consumption in normal-weight women reduced UA, TBARS levels, and SOD activity, whereas it increased UA and reduced PC levels in overweight/obese women, compared to the placebo. GP-derived bioactive compounds may exert antioxidant actions during the postprandial state in healthy women, through different mechanisms according to their BMI status.

Anti-Obesity and Anti-Hyperglycemic Effects of Meretrix lusoria Protamex Hydrolysate in ob/ob Mice

Meretrix lusoria (M. lusoria) is an economically important shellfish which is widely distributed in South Eastern Asia that contains bioactive peptides, proteins, and enzymes. In the present study, the extracted meat content of M. lusoria was enzymatic hydrolyzed using four different commercial proteases (neutrase, protamex, alcalase, and flavourzyme). Among the enzymatic hydrolysates, M. lusoria protamex hydrolysate (MLPH) fraction with MW ≤ 1 kDa exhibited the highest free radical scavenging ability. The MLPH fraction was further purified and an amino acid sequence (KDLEL, 617.35 Da) was identified by LC-MS/MS analysis. The purpose of this study was to investigate the anti-obesity and anti-hyperglycemic effects of MLPH containing antioxidant peptides using ob/ob mice. Treatment with MLPH for 6 weeks reduced body and organ weight and ameliorated the effects of hepatic steatosis and epididymal fat, including a constructive effect on hepatic and serum marker parameters. Moreover, hepatic antioxidant enzyme activities were upregulated and impaired glucose tolerance was improved in obese control mice. In addition, MLPH treatment markedly suppressed mRNA expression related to lipogenesis and hyperglycemia through activation of AMPK phosphorylation. These findings suggest that MLPH has anti-obesity and anti-hyperglycemic potential and could be effectively applied as a functional food ingredient or pharmaceutical.

Gender-Specific Behaviour in Obesity Stages I-II: Imbalance of Aminothiol Status and Adipomyokine Profile in Subjects with Different Insulin Resistance Severity

The hyperproduction of oxidative stress and inflammatory biomarkers, which is paralleled by decreased levels of antioxidant and anti-inflammatory mediators, is part of cellular mechanisms that contribute to the disruption of metabolic homeostasis in obesity. Whether gender-specific alterations and gender-restricted associations in these biomarkers underlie the increased cardiometabolic risk in men compared to women is unclear. We enrolled 31 women and 29 men, aged ≥50 and ≤70 years and with body mass index ≥ 30 and <40 kg/m². We assessed the concentrations of aminothiols (cysteine, homocysteine, and glutathione), expression of oxidant/antioxidant balance, adipomyokines (leptin, adiponectin, myostatin, and interleukin-6), markers of chronic inflammation, and vitamin D, an index of nutritional state, in plasma and serum samples by using HPLC, ELISA, and chemiluminescent immunoassay methods. We measured insulin resistance (IR) by the homeostasis model assessment (HOMA) index. Despite comparable levels of visceral adiposity, IR, and a similar dietary regimen, men showed, with respect to women, higher oxidant concentrations and lower antioxidant levels, which paralleled IR severity. Myostatin levels correlated with prooxidant aminothiols among men only. Gender-specific alterations in aminothiol status and adipomyokine profile and the gender-restricted association between these biomarkers and metabolic derangement are consistent with an increased cardiometabolic risk in men compared to age-matched women with stage I-II obesity. Strict control of redox and inflammatory status, even addressing gender-specific nutritional targets, may be useful to prevent obesity-related metabolic alterations and comorbidities.

Hydrogen Sulfide Prevents Mesenteric Adipose Tissue Damage, Endothelial Dysfunction, and Redox Imbalance From High Fructose Diet-Induced Injury in Aged Rats

A high fructose diet (HFD) and advanced age are key factors for the gradual loss of physiological integrity of adipose tissue. Endogenous hydrogen sulfide (H₂S) has beneficial effects on cytoprotection and redox balance. But its interactive effects on age-related damage of mesenteric vessels and connective and adipose tissues (MA) during HFD which could be the base of the development of effective physiological-based therapeutic strategy are unknown. The aim of study was to investigate age- and HFD-induced mesenteric cellular changes and activities of enzymes in H₂S synthesis and to test the effects of sodium hydrosulfide (NaHS) which is considered an H₂S donor on them. Adult and aged male rats on a standard diet (SD) or 4-week HFD were exposed to acute water-immersion restraint stress (WIRS) for evaluation of mesenteric subcellular and cellular adaptive responses by electron microscopy. The effects of exogenous NaHS (5.6 mg/kg/day for 9 days) versus vehicle on mesentery changes were investigated. Serum glucose level, thiobarbituric acid reactive substances (TBARS), and activities of cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS), thiosulfate-dithiol sulfurtransferase (TST), and sulfite oxidase (SO) were examined by spectrophotometry. In both adult and aged SD groups, treatment with NaHS protected mesenteric cells after WIRS. In both groups, the treatment with NaHS also protected MA mitochondria, microvascular endothelial and sub-endothelial structures, and fibroblasts versus the vehicle-treated group that had signs of damage. HFD increased MA injury and mitochondrial changes in both aged and adult rats. HFD-associated malfunction is characterized by low activities of CSE, CBS, TST, SO, and increased TBARS. Finally, we demonstrated that pretreatment with NaHS inhibited MA and mitochondria alterations in aged rats exposed to HFD and WIRS, lowered TBARS, and enhanced H₂S enzyme activities in contrast to the vehicle-treated group. Mitochondrial integrity alterations, endothelial damage, and redox imbalance are key factors for rat mesenteric adipose tissue damage during advanced age. These alterations and MA hypertrophic changes retain the central for HFD-induced damage. Moreover, H₂S signaling contributes to MA and mitochondria redox balance that is crucial for advanced age and HFD injury. The future study of H₂S donors’ effects on mesenteric cells is fundamental to define novel therapeutic strategies against metabolic changes.

Postprandial responses of circulating energy homeostasis mediators to single macronutrient challenges: influence of obesity and sex hormones

We analysed the influence of obesity, sex and sex steroids on the postprandial responses of circulating energy homeostasis mediators and their receptors to different macronutrient challenges. Seventeen women with polycystic ovary syndrome (PCOS, 8 with obesity), 17 non-hyperandrogenic control women (8 with obesity) and 19 control men (9 with obesity) were submitted, on alternate days, to isocaloric (300 kcal) oral glucose, lipid and protein loads. We evaluated serum ghrelin, leptin, soluble leptin receptor and adiponectin levels and the leukocyte gene expression of ghrelin (GHRL) and its receptor (GHSR), leptin receptor (LEPR) and adiponectin receptor 1 (ADIPOR1) during the macronutrient challenges. The postprandial responses of circulating energy homeostasis mediators were entirely different than those of their related genes. After macronutrient loads the postprandial response of serum energy homeostasis mediators showed a generalized physiological decrease that was blunted in subjects with obesity but was not influenced by sex, sex hormones or PCOS. However, gene expression of GHRL, LEPR and ADIPOR1 showed a marked increase following the ingestion of glucose compared with lipids and proteins, regardless of obesity and sex steroids. The physiological decrease after macronutrient loads, that was deregulated in obesity, did not reflect the acute leukocyte gene expression mainly after glucose, and may suggest a possible role for ghrelin, leptin and adiponectin in the postprandial inflammatory process.

Redox changes in obesity, metabolic syndrome, and diabetes

"Life is an instantaneous encounter of circulating matter and flowing energy" (Jean Giaja, Serbian physiologist), is one of the most elegant definitions not only of life but the relationship of redox biology and metabolism. Their evolutionary liaison has created inseparable yet dynamic homeostasis in health, which, when disrupted, leads to disease. This interconnection is even more pertinent today, in an era of increasing metabolic diseases of epidemic proportions such as obesity, metabolic syndrome, and diabetes. Despite great advances in understanding the molecular mechanisms of redox and metabolic regulation, we face significant challenges in preventing, diagnosing, and treating metabolic diseases. The etiological association and temporal overlap of these syndromes present significant challenges for the discrimination of appropriate clinical biomarkers for diagnosis, treatment, and outcome prediction. These multifactorial, multiorgan metabolic syndromes with complex etiopathogenic mechanisms are accompanied by disturbed redox equilibrium in target tissues and circulation. Free radicals and reactive species are considered both a causal factor and a consequence of disease status. Thus, determining the subtypes and levels of free radicals and reactive species, oxidatively damaged biomolecules (lipids, proteins, and nucleic acids) and antioxidant defense components as well as redox-sensitive transcription factors and fluxes of redox-dependent metabolic pathways will help define existing and establish novel redox biomarkers for stratifying metabolic diseases. This review aims to discuss diverse redox/metabolic aspects in obesity, metabolic syndrome, and diabetes, with the imperative to help establish a platform for emerging and future redox-metabolic biomarkers research in precision medicine. Future research warrants detailed investigations into the status of redox biomarkers in healthy subjects and patients, including the use of emerging 'omic' profiling technologies (e.g., redox proteomes, lipidomes, metabolomes, and transcriptomes), taking into account the influence of lifestyle (diet, physical activity, sleep, work patterns) as well as circadian ~24h fluctuations in circulatory factors and metabolites.

Contribution of Adipose Tissue Oxidative Stress to Obesity-Associated Diabetes Risk and Ethnic Differences: Focus on Women of African Ancestry

Adipose tissue (AT) storage capacity is central in the maintenance of whole-body homeostasis, especially in obesity states. However, sustained nutrients overflow may dysregulate this function resulting in adipocytes hypertrophy, AT hypoxia, inflammation and oxidative stress. Systemic inflammation may also contribute to the disruption of AT redox equilibrium. AT and systemic oxidative stress have been involved in the development of obesity-associated insulin resistance (IR) and type 2 diabetes (T2D) through several mechanisms. Interestingly, fat accumulation, body fat distribution and the degree of how adiposity translates into cardio-metabolic diseases differ between ethnicities. Populations of African ancestry have a higher prevalence of obesity and higher T2D risk than populations of European ancestry, mainly driven by higher rates among African women. Considering the reported ethnic-specific differences in AT distribution and function and higher levels of systemic oxidative stress markers, oxidative stress is a potential contributor to the higher susceptibility for metabolic diseases in African women. This review summarizes existing evidence supporting this hypothesis while acknowledging a lack of data on AT oxidative stress in relation to IR in Africans, and the potential influence of other ethnicity-related modulators (e.g., genetic-environment interplay, socioeconomic factors) for consideration in future studies with different ethnicities.

Commercial Vinegar Tablets Do Not Display the Same Physiological Benefits for Managing Postprandial Glucose Concentrations as Liquid Vinegar

Objective

Research evidence suggests that vinegar may effectively reduce postprandial glucose in both healthy adults and those with type 2 diabetes. There is heightened consumer interest in commercially available vinegar tablets; however, it is not known whether these products lower postprandial glycemia to the same extent as liquid vinegar. This crossover trial examined the impact of liquid vinegar versus commercial vinegar tablet ingestion at the start of a meal on the 60-minute glucose excursion postmeal in healthy adults.

Methods

Twelve young men and women (22.6 ± 0.6 y; 21.2 ± 1.2 kg/m²) completed this 4-arm Latin square crossover trial. Testing was separated by one week and consisted of a test meal (64 g carbohydrate) consumed immediately following one of the four oral treatments: CON, 60 g water (control treatment); VIN, 25 g liquid vinegar (5% acidity; 1.25 g acetic acid) diluted with 35 g water; PILL, four vinegar tablets (1.50 g acetic acid) swallowed whole with 60 g water; and PILL-c, four crushed vinegar tablets dissolved in 60 g water. Capillary blood glucose was tested in the fasted state and at 30 and 60 minutes postmeal.

Results

The 60-minute glucose excursion varied significantly by treatment (iAUC: 4.9 ± 0.6, 3.4 ± 0.4, 4.9 ± 0.6, and 4.1 ± 0.5 mmol˖h/l for CON, VIN, PILL, and PILL-c, respectively; F (3, 33) = 3.037, p = 0.043; repeated measures ANOVA). Post hoc analysis revealed a 31% reduction in the glucose postmeal excursion for VIN in comparison to CON and PILL (p = 0.040 and p = 0.049, respectively).

Conclusions

These data suggest that commercial vinegar tablets taken whole at mealtime are not as effective as liquid vinegar for reducing the postmeal glucose excursion in young, healthy adults.

Acute-phase glycoprotein profile responses to different oral macronutrient challenges: Influence of sex, functional hyperandrogenism and obesity

Acute-phase glycoprotein ¹H-NMR spectroscopy profiles serve as surrogate markers of chronic inflammation in metabolic disorders such as obesity, diabetes and polycystic ovary syndrome (PCOS). The latter is associated with increased height-to-width (H/W) ratios of GlycA and GlycB after fasting, but not to glycoprotein areas, regardless of obesity. We studied the responses to separate glucose, lipid and protein oral challenges of five glycoprotein variables (GlycA, GlycB, and GlycF areas and the GlycA and GlycB H/W ratios) in 17 women with PCOS, 17 control women, and 19 healthy men. Glucose and protein ingestion resulted into decreases in all glycoprotein variables, whereas lipid ingestion increased GlycA, GlycF and induced minimal changes in GlycB and GlycB H/W. We found no effects of obesity or group of subjects on postprandial glycoprotein variables regardless of the macronutrient being ingested. However, a statistically significant interaction indicated that obesity blunted the decrease in some of these variables in control women and men, whereas obese women with PCOS showed larger changes when compared with their non-obese counterparts. In conclusion, acute-phase glycoprotein profiles indicate an anti-inflammatory response during postprandial phase that is less pronounced after lipid ingestion, and is counteracted by the chronic inflammatory background associated with obesity and PCOS.

Postprandial Glycemia, Insulinemia, and Antioxidant Status in Healthy Subjects after Ingestion of Bread made from Anthocyanin-Rich Riceberry Rice

Riceberry rice, a gluten-free grain, contains many nutrient components, including carbohydrates, proteins, certain fatty acids, and micronutrients, as well as bioactive non-nutrient compounds, such as polyphenolic compounds. This study aimed to evaluate the effect of bread made from anthocyanin-rich Riceberry rice on the postprandial glycemic response, glucagon-like peptide-1 (GLP-1), antioxidant status, and subjective ratings of appetite. In the crossover design, 16 healthy participants (six men and 10 women) completed four sessions involving blood collection in the fasting state and at 30, 60, 90, 120, 150, and 180 min after food consumption (50 g of available carbohydrate) in a randomized order: 1) glucose solution, 2) wheat bread (WB), 3) Riceberry rice bread (RRB), and 4) Hom Mali bread (HMB). Consumption of RRB resulted in significantly lower postprandial plasma glucose concentration at 30 and 60 min when compared to HMB. No difference in postprandial glucose concentration between RRB and WB was observed. In addition, postprandial plasma insulin showed a significant decrease in the group which received RRB at 15 and 60 min, as compared to HMB. In comparison with 50 g of glucose, as a reference, the glycemic index (GI) of RRB, WB, and HMB was 69.3 ± 4.4, 77.8 ± 4.6, and 130.6 ± 7.9, respectively. Interestingly, the ferric-reducing ability of plasma (FRAP) level was shown to significantly increase after consumption of RRB. In the meantime, a significant decrease in the postprandial FRAP level was also observed following an intake of WB and HMB. All breads caused increases in the postprandial plasma protein thiol group and had similar effects on hunger, fullness, desire to eat, and satiety ratings. However, consumption of RBB, WB, and HMB did not change plasma GLP-1 and malondialdehyde (MDA) levels when compared to the baseline. The findings suggest that anthocyanin-rich Riceberry rice can be a natural ingredient for gluten-free bread which reduced glycemic response together with improvement of antioxidant status in healthy subjects.

TLR2 and TLR4 Surface and Gene Expression in White Blood Cells after Fasting and Oral Glucose, Lipid and Protein Challenges: Influence of Obesity and Sex Hormones

We studied if macronutrients of the diet have different effects on leukocyte activation, and if these effects are influenced by sex hormones or obesity. We analyzed leukocyte cell surface and gene expression of toll-like receptors 2 and 4 (TLR2 and TLR4) during fasting and after macronutrient loads in women with polycystic ovary syndrome and female and male controls. Fasting TLR2 surface expression in neutrophils was higher in men than in women. Obese subjects presented higher TLR2 gene expression than nonobese individuals, particularly in men. In contrast, surface TLR4 expression was lower in men and in obese individuals. Postprandial cell-surface expression decreased similarly after all macronutrient loads. Neutrophil TLR2 decreased only in obese subjects whereas TLR4 showed a greater decrease in nonobese individuals. However, TLR2 gene expression increased after glucose ingestion and decreased during the lipid load, while TLR4 was induced in response to lipids and mostly to glucose. Postprandial TLR gene expression was not influenced by group of subjects or obesity. Both cell-surface and gene postprandial expression inversely correlated with their fasting levels. These responses suggest a transient compensatory response aiming to prevent postprandial inflammation. However, obesity and sex hormones showed opposite influences on surface expression of TLR2 and TLR4, but not on their gene expression, pointing to regulatory posttranscriptional mechanisms.

Hesperidin: A Therapeutic Agent For Obesity

Obesity is a chronic metabolic disease caused by multiple factors and is considered to be a risk factor for type 2 diabetes, cardiovascular disease, hypertension, stroke and various cancers. Hesperidin, a flavanone glycoside, is a natural phenolic compound with a wide range of biological effects. Mounting evidence has demonstrated that hesperidin possesses inhibitory effect against obesity diseases. Our review discusses mechanisms of hesperidin in the treatment of obesity. Hesperidin regulates lipid metabolism and glucose metabolism by mediating AMPK and PPAR signaling pathways, directly regulates antioxidant index and anti-apoptosis, and indirectly mediates NF-κB signaling pathway to regulate inflammation to play a role in the treatment of obesity. In addition, hesperidin-enriched dietary supplements can significantly improve symptoms such as postprandial hyperglycemia and hyperlipidemia. Further clinical trials are also required for confirming lipid-lowering efficacy of this natural flavonoid and evaluating its safety profile.

Antioxidant, hepatoprotective, genoprotective, and cytoprotective effects of quercetin in a murine model of arthritis

Rheumatoid arthritis is a highly debilitating inflammatory autoimmune disease which is characterized by joint destruction. The present study sought to investigate the effect of quercetin in rats with complete Freund's adjuvant-induced arthritis. Animals were divided into control/saline, control/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg) arthritis/saline, and arthritis/quercetin (5 mg/kg, 25 mg/kg, and 50 mg/kg); the treatments were administered for 45 days. Biochemical, oxidative stress, genotoxicity, and cytotoxicity parameters were evaluated. All doses of quercetin reduced the levels of aspartate aminotransferase, thiobarbituric acid-reactive substances, and reactive oxygen species; however, only treatment with 25 or 50 mg/kg increased catalase activity. Total thiol and reduced glutathione levels were not significantly affected by the induction nor by the treatments. Genotoxicity assessed by DNA damage, and cytotoxicity through picogreen assay, decreased after treatments with quercetin. Our results present evidence of the antioxidant, cytoprotective, genoprotective and hepatoprotective, and effects of quercetin, demonstrating its potential as a candidate for coadjuvant therapy.

Metabolic Cytokines at Fasting and During Macronutrient Challenges: Influence of Obesity, Female Androgen Excess and Sex

Scope: Cytokines have pleiotropic functions within the organism and their levels may be influenced by obesity, visceral adiposity and sex hormones. Diet composition may also affect their systemic concentrations during fasting and in the postprandial period. Hence, we studied the influence of sex steroids and obesity on the circulating levels of a panel of metabolic cytokines in the fasting state and after single macronutrient challenges. Methods: On alternate days we submitted 17 women with polycystic ovary syndrome (PCOS) (9 non-obese, 8 obese), 17 non-hyperandrogenic control women (9 non-obese, 8 obese) and 19 control men (10 non-obese, 9 obese) to isocaloric oral glucose, lipid and protein loads. Serum levels of omentin-1, vaspin, lipocalin-2, adipsin, PAI-1, chemerin, FGF-21 and FGF-23 were determined by Luminex multiplex technology. Results: During fasting, obese patients presented higher levels of PAI-1, chemerin and adipsin but decreased FGF-23 and omentin-1 compared with non-obese subjects. Vaspin showed sexual dimorphism with lower levels in men than women with PCOS and female controls. Following macronutrient ingestion, most metabolic cytokines presented a similar physiological response consisting of a decrease in circulating concentrations, which was inversely associated with the fasting levels of these molecules. Protein intake caused the major postprandial decrease whereas glucose did not significantly reduce PAI-1, FGF-23 and vaspin, and even increased FGF-21. Regardless of the macronutrient administered, vaspin levels showed a larger reduction in non-obese individuals while the decrease in PAI-1 was particularly noticeable in the obese subgroup. The postprandial reductions of omentin-1 and FGF-23 after glucose and protein loads were influenced by obesity. No major differences were found between patients with PCOS and male and female controls. Conclusions: Obesity, but not PCOS or sex, markedly influences metabolic cytokine levels at fasting and after macronutrient ingestion. The observed postprandial decrease in their circulating concentrations might represent a physiological compensatory mechanism against food-induced inflammation and oxidative stress. This mechanism is altered by obesity and is differently modulated by macronutrients, suggesting a larger contribution of glucose to stressful postprandial responses.

Effect of Acute Ingestion of Green Tea Extract and Lemon Juice on Oxidative Stress and Lipid Profile in Pigs Fed a High-Fat Diet

Green tea and its catechins have been shown to ameliorate high fat diet-induced oxidative stress and hyperlipidemia. However, low bioavailability of catechins limits their therapeutic potential. Lemon juice (LJ) has been suggested to enhance the bioavailability of catechins in vitro. This study investigated the antioxidative and hypolipidemic efficacy of a single dose of green tea extract (GTE) or GTE plus LJ (GTE + LJ) in high-fat diet fed pigs. Sixteen pigs ingested a single dose of GTE (190 mg/kg/day) or GTE + LJ (0.75 mL/kg/day) mixed with low-fat (LF; 5% fat) or high-fat (HF; 22% fat) diets and blood samples were collected for 24 h. Plasma catechin level peaked at two hours, and gradually returned to baseline after six hours following the intake. The addition of LJ significantly increased plasma catechin level. The diet containing GTE did not lower plasma cholesterol and triacylglycerol (TG) concentrations, superoxide dismutase (SOD) and catalase activity, or malondialdehyde concentration in 24 h in HF-fed pigs. Addition of a single dose of LJ, however, significantly decreased plasma TG level in LF groups but did not cause further changes on any other markers compared to the GTE alone. Our findings indicate limited effect of a single meal containing GTE on plasma antioxidant enzymes, lipid profile, and lipid peroxidation in pigs and no significant synergistic/additive action of adding LJ to GTE within 24 h in pigs. A study with a longer treatment period is warranted to further understand the potential role of GTE in reducing HF diet-induced oxidative stress and the possible synergistic role of LJ.

Postprandial inflammatory responses after oral glucose, lipid and protein challenges: Influence of obesity, sex and polycystic ovary syndrome

BACKGROUND & AIMS

Most evidence linking the polycystic ovary syndrome (PCOS) with chronic low-grade inflammation has been obtained in the fasting state. We have studied the postprandial inflammatory response to oral glucose, lipid and protein challenges and the possible influences of obesity, sex and PCOS on these responses.

METHODS

On alternate days, we submitted 17 women with PCOS (9 non-obese, 8 obese), 17 control women (9 non-obese, 8 obese) and 19 control men (10 non-obese, 9 obese) to isocaloric (300 Kcal) oral macronutrient loads. We assayed serum for TNF-α, IL-6, IL-18, IL-10, pentraxin-3 and galectin-3 concentrations and leukocytes for expression of TNF, IL6, IL10 and their receptors TNFRSF1B, IL6R and IL10RA.

RESULTS

Circulating IL-6 levels decreased after glucose and protein ingestion but slightly increased after oral lipid intake. Leukocyte IL6 expression did not change after the ingestion of any macronutrient yet IL6R expression increased during all macronutrient challenges, the largest increase being observed after glucose ingestion. Serum TNF-α similarly decreased during either macronutrient load, whereas TNF expression increased after macronutrient ingestion, the highest increase observed after oral glucose. TNFRSF1B expression also increased after glucose intake but not after lipid or protein ingestion. No global effect of obesity or group on postprandial circulating IL-6, TNF-α, or IL6, IL6R, TNF and TNFRSF1B expression was found. Circulating IL-18 concentrations decreased during all oral challenges, whereas in case of galectin-3 and pentraxin-3 only the protein load caused a reduction in its concentrations. Of the genes studied here, IL10 showed the largest increase in expression throughout all the postprandial curves, particularly after glucose. Obesity blunted the increase in IL10 expression. IL10RA expression decreased after glucose ingestion but remained unchanged during lipid and protein loads.

CONCLUSIONS

Glucose ingestion, as opposed to lipid and protein intake, results into the largest increase in leukocyte gene expression of inflammatory mediators. The expression of the anti-inflammatory cytokine IL10 was the largest observed here, suggesting a compensatory mechanisms against postprandial inflammation that may be blunted in obesity. However, these responses did not translate into the circulating concentrations of these inflammatory mediators during the immediate postprandial phase.

Association Between Selenium and Malondialdehyde as an Efficient Biomarker of Oxidative Stress in Infantile Cardiac Surgery

The present work describes a method to quantify the level of oxidative stress in infantile cardiac surgery. Fifteen patients, 6 girls and 9 boys, aged between 3 months and 16 years were divided into three groups. The first group sought to quantify the oxidative stress from differing concentrations of selenium. The second group used malondialdehyde as an indicator of oxidative stress. Finally, the third group quantified oxidative stress by normalizing the selenium concentration via malondialdehyde. Blood aliquots of 1.50 ml, drawn from the radial artery, were collected and centrifuged for quantification of Se and MDA in plasma. The statistical method ANOVA was used with a 95% confidence interval to indicate significant statistical differences between the post- and pre-operative stage for each group. The concentrations of malondialdehyde were measured by using UV-Vis following the thiobarbituric acid reaction method. For quantification of selenium, the samples were submitted to assisted microwave digestion and measured by ICP OES. In the first two groups, it was not possible to affirm that selenium and malondialdehyde could be biomarkers of oxidative stress, so a statistic test (ANOVA) was performed. However, the selenium/malondialdehyde ratios in the pre-operative and post-operative stage were 2.10 ± 0.70 and 3.20 ± 0.40, respectively. The ANOVA test confirmed a statistically significant difference between the pre- and post-operative stages with p value = 0.004. Here, the ratio of selenium concentration by malondialdehyde was confirmed to be an effective parameter for demonstration and quantification of oxidative stress activity at the post-operative stage.