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1.
Artigo em Inglês | MEDLINE | ID: mdl-31982985

RESUMO

The bacterial production of acetate via reductive acetogenesis along the Wood-Ljungdahl metabolic pathway is an important source of this molecule in several environments, ranging from industrial bioreactors to the human gastrointestinal tract. Here, we contributed to the study of reductive acetogens by considering mathematical modelling techniques for the prediction of bacterial growth and acetate production. We found that the incorporation of a hydrogen uptake concentration threshold into the models improves their predictions and we calculated this threshold as 86.2 mM (95% confidence interval 6.1-132.6 mM). Monod kinetics and first-order kinetics models, with the inclusion of two candidate threshold terms or reversible Michaelis-Menten kinetics, were compared to experimental data and the optimal formulation for predicting both growth and metabolism was found. The models were then used to compare the efficacy of two growth media for acetogens. We found that the recently described general acetogen medium was superior to the DSMZ medium in terms of unbiased estimation of acetogen growth and investigated the contribution of yeast extract concentration to acetate production and bacterial growth in culture. The models and their predictions will be useful to those studying both industrially and environmentally relevant reductive acetogenesis and allow for straightforward adaptation to similar cases with different organisms.

2.
J Dairy Sci ; 102(12): 10772-10778, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31629525

RESUMO

Colostrum plays an important role in initiating the development of the intestinal barrier in newborn mammals. Given its bioactivity, there is much interest in the potential use of bovine colostrum to improve human gastrointestinal health throughout the life span. There is evidence that bovine colostrum is effective at improving small intestinal barrier integrity and some indication that it may alter colonic motility. However, for colostrum to be used as a product to improve intestinal health, it needs to be bioactive after processing. The aim of this study was to determine whether industrial processing of bovine colostrum affects its ability to improve small intestinal barrier integrity or alter distal colon motility. Three colostrum sample types were compared; raw whole colostrum powder (WCP), raw skim colostrum powder (SCP), and industrially produced colostrum milk protein concentrate (CMPC). To determine whether these colostrum powders had different effects on small intestinal barrier integrity, their effects on the transepithelial electrical resistance across an in vitro intestinal epithelial layer (Caco-2 cells) were measured, both with and without a challenge from the proinflammatory cytokine tumor necrosis factor-α. These results showed that CMPC enhanced transepithelial electrical resistance across unchallenged epithelial cell layers, whereas the raw colostrum samples, WCP and SCP, did not have an effect. The colostrum samples were also compared to determine how they affect contractility in the distal colon isolated from the rat. Skim colostrum powder was the only sample to act directly on colonic tissue to modulate motility, increasing the amplitude of contractions. The results show that bovine colostrum is able to improve small intestinal barrier integrity and alter colon motility, and they implicate different components. The barrier integrity enhancement was apparent only in the industrial CMPC, which may have been due to the increase in protein concentration or the release of small peptides as a result of processing. The ability to alter colon motility was present in SCP but absent in WCP, again implying that an increase in protein concentration is responsible for the effect. However, this effect was not apparent for the industrially processed CMPC, suggesting denaturation or degradation of the active component. The beneficial effect of colostrum on small intestinal barrier integrity was present after processing, confirming that it is feasible to industrially produce an active product for gut health.


Assuntos
Colostro , Mucosa Intestinal/efeitos dos fármacos , Proteínas do Leite/farmacologia , Animais , Células CACO-2 , Bovinos , Humanos , Proteínas do Leite/metabolismo , Ratos , Fator de Necrose Tumoral alfa/metabolismo
3.
Sci Rep ; 9(1): 14026, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575902

RESUMO

Stress negatively impacts gut and brain health. Individual differences in response to stress have been linked to genetic and environmental factors and more recently, a role for the gut microbiota in the regulation of stress-related changes has been demonstrated. However, the mechanisms by which these factors influence each other are poorly understood, and there are currently no established robust biomarkers of stress susceptibility. To determine the metabolic and microbial signatures underpinning physiological stress responses, we compared stress-sensitive Wistar Kyoto (WKY) rats to the normo-anxious Sprague Dawley (SD) strain. Here we report that acute stress-induced strain-specific changes in brain lipid metabolites were a prominent feature in WKY rats. The relative abundance of Lactococcus correlated with the relative proportions of many brain lipids. In contrast, plasma lipids were significantly elevated in response to stress in SD rats, but not in WKY rats. Supporting these findings, we found that the greatest difference between the SD and WKY microbiomes were the predicted relative abundance of microbial genes involved in lipid and energy metabolism. Our results provide potential insights for developing novel biomarkers of stress vulnerability, some of which appear genotype specific.

4.
Metabolites ; 9(11)2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31661817

RESUMO

Holistic benefits of human milk to infants, particularly brain development and cognitive behavior, have stipulated that infant formula be tailored in composition like human milk. However, the composition of human milk, especially lipids, and their effects on brain development is complex and not fully elucidated. We evaluated brain lipidome profiles in weanling rats fed human milk or infant formula using non-targeted UHPLC-MS techniques. We also compared the lipid composition of human milk and infant formula using conventional GC-FID and HPLC-ELSD techniques. The sphingomyelin class of lipids was significantly higher in brains of rats fed human milk. Lipid species mainly comprising saturated or mono-unsaturated C18 fatty acids contributed significantly higher percentages to their respective classes in human milk compared to infant formula fed samples. In contrast, PUFAs contributed significantly higher percentages in brains of formula fed samples. Differences between human milk and formula lipids included minor fatty acids such as C8:0 and C12:0, which were higher in formula, and C16:1 and C18:1 n11, which were higher in human milk. Formula also contained higher levels of low- to medium-carbon triacylglycerols, whereas human milk had higher levels of high-carbon triacylglycerols. All phospholipid classes, and ceramides, were higher in formula. We show that brain lipid composition differs in weanling rats fed human milk or infant formula, but dietary lipid compositions do not necessarily manifest in the brain lipidome.

5.
Nutrients ; 11(9)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547446

RESUMO

Higher dietary protein intake is increasingly recommended for the elderly; however, high protein diets have also been linked to increased cardiovascular disease (CVD) risk. Trimethylamine-N-oxide (TMAO) is a bacterial metabolite derived from choline and carnitine abundant from animal protein-rich foods. TMAO may be a novel biomarker for heightened CVD risk. The purpose of this study was to assess the impact of a high protein diet on TMAO. Healthy men (74.2 ± 3.6 years, n = 29) were randomised to consume the recommended dietary allowance of protein (RDA: 0.8 g protein/kg bodyweight/day) or twice the RDA (2RDA) as part of a supplied diet for 10 weeks. Fasting blood samples were collected pre- and post-intervention for measurement of TMAO, blood lipids, glucose tolerance, insulin sensitivity, and inflammatory biomarkers. An oral glucose tolerance test was also performed. In comparison with RDA, the 2RDA diet increased circulatory TMAO (p = 0.002) but unexpectedly decreased renal excretion of TMAO (p = 0.003). LDL cholesterol was increased in 2RDA compared to RDA (p = 0.049), but no differences in other biomarkers of CVD risk and insulin sensitivity were evident between groups. In conclusion, circulatory TMAO is responsive to changes in dietary protein intake in older healthy males.

6.
Artigo em Inglês | MEDLINE | ID: mdl-31480414

RESUMO

Physical activity plays an important role in the maintenance of bone health from childhood through adulthood. This study aimed to explore the associations between self-reported physical activity (PA), activity energy expenditure (AEE), heel ultrasound parameters and bone health measures among older adult women. The AEE was estimated from the responses of questionnaires for 125 older adult women aged 54-81 years. The bone parameters were measured by dual energy x-ray absorptiometry (DXA) and heel ultrasound parameters by the heel quantitative ultrasound (QUS). This study showed that AEE and the metabolic equivalent task (MET) were positively correlated with the bone and heel ultrasound parameters. However, fat mass (FM) and fat percentage were negatively correlated with AEE and MET. In addition, the regression analysis showed that higher AEE was a strong predictor of a higher spine T-score (ß = 0.212, p = 0.015), QUS T-score (ß = 0.239, p = 0.011) and stiffness index (ß = 0.240, p = 0.010) after adjusting for age, fat mass, lean mass, height and calcium intake. These results contribute to our understanding of the importance of physical activity in postmenopausal women by reiterating the benefits of physical activity for older adult women. Physical activity is an important tool for the prevention and management of osteoporosis.

7.
Front Microbiol ; 10: 1652, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31379794

RESUMO

Sulphate-reducing bacteria (SRB) are studied across a range of scientific fields due to their characteristic ability to metabolise sulphate and produce hydrogen sulphide, which can lead to significant consequences for human activities. Importantly, they are members of the human gastrointestinal microbial population, contributing to the metabolism of dietary and host secreted molecules found in this environment. The role of the microbiota in host digestion is well studied, but the full role of SRB in this process has not been established. Moreover, from a human health perspective, SRB have been implicated in a number of functional gastrointestinal disorders such as Irritable Bowel Syndrome and the development of colorectal cancer. To assist with the study of SRB, we present a mathematical model for the growth and metabolism of the well-studied SRB, Desulfovibrio vulgaris in a closed system. Previous attempts to model SRB have resulted in complex or highly specific models that are not easily adapted to the study of SRB in different environments, such as the gastrointestinal tract. We propose a simpler, Monod-based model that allows for easy alteration of both key parameter values and the governing equations to enable model adaptation. To prevent any incorrect assumptions about the nature of SRB metabolic pathways, we structure the model to consider only the concentrations of initial and final metabolites in a pathway, which circumvents the current uncertainty around hydrogen cycling by SRB. We parameterise our model using experiments with varied initial substrate conditions, obtaining parameter values that compare well with experimental estimates in the literature. We then validate our model against four independent experiments involving D. vulgaris with further variations to substrate availability. Further use of the model will be possible in a number of settings, notably as part of larger models studying the metabolic interactions between SRB and other hydrogenotrophic microbes in the human gastrointestinal tract and how this relates to functional disorders.

8.
Immun Ageing ; 16: 15, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31333751

RESUMO

Background: Cytokines, chemokines, C-reactive proteins (CRP) and ferritin are known inflammatory markers. However, cytokines such as interleukin (IL-1ß), (IL-6) and tumour necrosis factor (TNF-α) have been reported to interfere with both the bone resorption and bone formation processes. Similarly, immune cell cytokines are known to contribute to inflammation of the adipose tissue especially with obesity. IL-10 but not IL-33 has been linked to lower ferritin levels and anemia. In this study, we hypothesized that specific cytokine levels in the plasma of women with low bone mineral density (BMD) would be higher than those in the plasma of healthy women due to the actions of elevated levels of pro-inflammatory cytokines in inducing osteoclast formation and differentiation during senescence. Results: Levels of cytokines (IFNα2, IFN-γ, IL-12p70, IL-33) and monocyte chemoattractant protein-1 (MCP-1) were significantly higher in the plasma of the osteoporotic group compared to the osteopenic and/or healthy groups. Meanwhile CRP levels were significantly lower in women with osteoporosis (P = 0.040) than the osteopenic and healthy groups. Hip BMD values were significantly lower in women with high/detectable values of IL-1ß (P = 0.020) and IL-6 (P = 0.030) compared to women where these were not detected. Similarly, women with high/detectable values of IL-1ß had significantly lower spine BMD than those where IL-1ß was not detected (P = 0.030). Participants' CRP levels were significantly positively correlated with BMI, fat mass and fat percentage (P < 0.001). In addition, ferritin levels of women with high/detectable values of anti-osteoclastogenic IL-10 (P = 0.012) and IL-33 (P = 0.017) were significantly lower than those where these were not detected. There was no statistically significant association between TNF-α and BMD of the hip and lumbar spine. Conclusions: High levels of cytokines (IFNα2, IFN-γ, IL-12p70, IL-33) and MCP-1 in apparently healthy postmenopausal women are associated with bone health issues. In addition, an increase in levels of IL-10 and IL-33 may be associated with low ferritin levels in this age group. Trial registration: ANZCTR, ACTRN12617000802303. Registered May 31st, 2017, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373020.

9.
Microorganisms ; 7(7)2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31277402

RESUMO

Glycans are present exogenously in the diet, expressed and secreted endogenously by host cells, and produced by microbes. All of these processes result in them being available to the gut microbiome, firmly placing glycans at the interface of diet-microbe-host interactions. The most dramatic shift in dietary sources of glycans occurs during the transition from the milk-based neonatal diet to the diverse omnivorous adult diet, and this has profound effects on the composition of the gut microbiome, gene expression by microbes and host cells, mucin composition, and immune development from innate towards adaptive responses. Understanding the glycan-mediated interactions occurring during this transitional window may inform dietary recommendations to support gut and immune development during a vulnerable age. This review aims to summarise the current state of knowledge on dietary glycan mediated changes that may occur in the infant gut microbiome and immune system during weaning.

10.
Eur J Nutr ; 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31325042

RESUMO

PURPOSE: Human breast milk is the optimal source of nutrients for growing infants. However, many circumstances can arise which preclude breast milk feeding, leading to the use of infant formula, including during the weaning period. Many diet-related effects are modulated by the gut microbiome. Therefore, we investigated the effect of human milk (HM) or infant formula (IF) on the gut microbiota in weanling rats. METHODS: The gut microbiota of weanling male Sprague-Dawley rats fed HM or IF for 28 days was analysed by shotgun metagenome sequencing. Caecal contents were analysed by liquid chromatography-mass spectrometry metabolomics. RESULTS: Numerous genera within the Proteobacteria phylum were relatively more abundant in the ileum, caecum, and colon of rats fed HM, including ileal Escherichia (HM = 9.6% ± 4.3 SEM; IF = 0.9% ± 0.3 SEM; P = 0.03). Other taxa that differed between HM- and IF-fed rats included Prevotella and Ruminococcus. Overall, more differences were observed in the ileum than the caecum and colon between rats fed HM and IF. For the rats fed IF, in the ileum, the relative abundance of Bifidobacterium was higher (HM = 1.7% ± 0.7 SEM; IF = 5.0% ± 1.5 SEM; P = 0.04) with gene functions related to carbohydrate and amino acid metabolism also decreased. In the caecum, metabolic features such as bile acids were elevated while amino sugars were also decreased. CONCLUSION: Our results show that HM and IF composition differences are reflected in the gut microbiome composition and function in both the small and large intestines.

11.
Front Microbiol ; 10: 458, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30930871

RESUMO

A variety of fermented foods have been linked to improved human health, but their impacts on the gut microbiome have not been well characterized. Dairy products are one of the most popular fermented foods and are commonly consumed worldwide. One area we currently lack data on is how the process of fermentation changes the gut microbiota upon digestion. What is even less well characterized are the possible differences between cow and other mammals' milks. Our aim was to compare the impact of unfermented skim milk and fermented skim milk products (milk/yogurt) originating from two species (cow/sheep) on the gut microbiome using a rat model. Male Sprague-Dawley rats were fed a dairy-free diet supplemented with one of four treatment dairy drinks (cow milk, cow yogurt, sheep milk, sheep yogurt) for 2 weeks. The viable starter culture bacteria in the yogurts were depleted in this study to reduce their potential influence on gut bacterial communities. At the end of the study, cecal samples were collected and the bacterial community profiles determined via 16S rRNA high-throughput sequencing. Fermentation status drove the composition of the bacterial communities to a greater extent than their animal origin. While overall community alpha diversity did not change among treatment groups, the abundance of a number of taxa differed. The cow milk supplemented treatment group was distinct, with a higher intragroup variability and a distinctive taxonomic composition. Collinsella aerofaciens was of particularly high abundance (9%) for this group. Taxa such as Firmicutes and Lactobacillus were found in higher abundance in communities of rats fed with milk, while Proteobacteria, Bacteroidetes, and Parabacteroides were higher in yogurt fed rats. Collinsella was also found to be of higher abundance in both milk (vs. yogurt) and cows (vs. sheep). This research provides new insight into the effects of unfermented vs. fermented milk (yogurt) and animal origin on gut microbial composition in a healthy host. A number of differences in taxonomic abundance between treatment groups were observed. Most were associated with the effects of fermentation, but others the origin species, or in the case of cow milk, unique to the treatment group. Future studies focusing on understanding microbial metabolism and interactions, should help unravel what drives these differences.

12.
Mol Nutr Food Res ; 63(8): e1800811, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30892810

RESUMO

SCOPE: MicroRNA are critical to the coordinated post-transcriptional regulation of gene expression, yet few studies have addressed the influence of habitual diet on microRNA expression. High protein diets impact cardiometabolic health and body composition in the elderly suggesting the possibility of a complex systems response. Therefore, high-throughput small RNA sequencing technology is applied in response to doubling the protein recommended dietary allowance (RDA) over 10 weeks in older men to examine alterations in circulating miRNAome. METHODS AND RESULTS: Older men (n = 31; 74.1 ± 0.6 y) are randomized to consume either RDA (0.8 g kg-1  day-1 ) or 2RDA (1.6 g kg-1  day-1 ) of protein for 10 weeks. Downregulation of five microRNAs (miR-125b-5p, -100-5p, -99a-5p, -23b-3p, and -203a) is observed following 2RDA with no changes in the RDA. In silico functional analysis highlights target gene enrichment in inflammation-related pathways. qPCR quantification of predicted inflammatory genes (TNFα, IL-8, IL-6, pTEN, PPP1CB, and HOXA1) in peripheral blood mononuclear cells shows increased expression following 2RDA diet (p ≤ 0.05). CONCLUSION: The study findings suggest a possible selective alteration in the post-transcriptional regulation of the immune system following a high protein diet. However, very few microRNAs are altered despite a large change in the dietary protein.


Assuntos
Ácidos Nucleicos Livres/sangue , Proteínas na Dieta/farmacologia , MicroRNAs/sangue , Idoso , Proteínas na Dieta/administração & dosagem , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Inflamação/genética , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/fisiologia , Masculino , RNA Mensageiro , Recomendações Nutricionais
13.
Nutrients ; 11(2)2019 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-30744134

RESUMO

Complementary feeding transitions infants from a milk-based diet to solid foods, providing essential nutrients to the infant and the developing gut microbiome while influencing immune development. Some of the earliest microbial colonisers readily ferment select oligosaccharides, influencing the ongoing establishment of the microbiome. Non-digestible oligosaccharides in prebiotic-supplemented formula and human milk oligosaccharides promote commensal immune-modulating bacteria such as Bifidobacterium, which decrease in abundance during weaning. Incorporating complex, bifidogenic, non-digestible carbohydrates during the transition to solid foods may present an opportunity to feed commensal bacteria and promote balanced concentrations of beneficial short chain fatty acid concentrations and vitamins that support gut barrier maturation and immunity throughout the complementary feeding window.


Assuntos
Microbioma Gastrointestinal , Fórmulas Infantis , Fenômenos Fisiológicos da Nutrição do Lactente , Leite Humano , Prebióticos , Aleitamento Materno , Microbioma Gastrointestinal/imunologia , Microbioma Gastrointestinal/fisiologia , Humanos , Lactente , Leite Humano/química , Leite Humano/imunologia , Leite Humano/microbiologia , Oligossacarídeos/metabolismo , Desmame
14.
Gut Microbes ; 10(3): 270-288, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30563420

RESUMO

Hydrogen plays a key role in many microbial metabolic pathways in the human gastrointestinal tract (GIT) that have an impact on human nutrition, health and wellbeing. Hydrogen is produced by many members of the GIT microbiota, and may be subsequently utilized by cross-feeding microbes for growth and in the production of larger molecules. Hydrogenotrophic microbes fall into three functional groups: sulfate-reducing bacteria, methanogenic archaea and acetogenic bacteria, which can convert hydrogen into hydrogen sulfide, methane and acetate, respectively. Despite different energy yields per molecule of hydrogen used between the functional groups, all three can coexist in the human GIT. The factors affecting the numerical balance of hydrogenotrophs in the GIT remain unconfirmed. There is increasing evidence linking both hydrogen sulfide and methane to GIT diseases such as irritable bowel syndrome, and strategies for the mitigation of such health problems through targeting of hydrogenotrophs constitute an important field for further investigation.


Assuntos
Archaea/metabolismo , Bactérias/metabolismo , Microbioma Gastrointestinal/fisiologia , Hidrogênio/metabolismo , Acetatos/metabolismo , Animais , Archaea/classificação , Bactérias/classificação , Gastroenteropatias/etiologia , Gastroenteropatias/microbiologia , Gastroenteropatias/terapia , Microbioma Gastrointestinal/efeitos dos fármacos , Humanos , Sulfeto de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/toxicidade , Metano/metabolismo , Metano/toxicidade
15.
J Nutr ; 2019 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31891398

RESUMO

The food we consume and its interactions with the host and their gut microbiota affect normal gut function and health. Functional gut disorders (FGDs), including irritable bowel syndrome (IBS), can result from negative effects of these interactions, leading to a reduced quality of life. Certain foods exacerbate or reduce the severity and prevalence of FGD symptoms. IBS can be used as a model of perturbation from normal gut function with which to study the impact of foods and diets on the severity and symptoms of FGDs and understand how critical processes and biochemical mechanisms contribute to this impact. Analyzing the complex interactions between food, host, and microbial metabolites gives insights into the pathways and processes occurring in the gut which contribute to FGDs. The following review is a critical discussion of the literature regarding metabolic pathways and dietary interventions relevant to FGDs. Many metabolites, for example bile acids, SCFAs, vitamins, amino acids, and neurotransmitters, can be altered by dietary intake, and could be valuable for identifying perturbations in metabolic pathways that distinguish a "normal, healthy" gut from a "dysfunctional, unhealthy" gut. Dietary interventions for reducing symptoms of FGDs are becoming more prevalent, but studies investigating the underlying mechanisms linked to host, microbiome, and metabolite interactions are less common. Therefore, we aim to evaluate the recent literature to assist with further progression of research in this field.

16.
Bone Rep ; 9: 173-180, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30480061

RESUMO

The aim of this study was to validate the combination of ovariectomy and glucocorticoid treatment in sheep as a large animal model for osteoporosis by measuring the concentration of specific biomarkers in the blood of the sheep and measuring bone loss over five months. Aged Merino ewes were randomly allocated into four groups: control, ovariectomy (OVX), and two OVX groups receiving glucocorticoids-one group once-monthly for five months (OVXG), and the other for two months followed by no treatment for three months (OVXG2). Parameters measured were biochemical markers of bone turnover, areal bone mineral density, volumetric bone mineral density, and total and trabecular bone parameters. Ovariectomy increased the concentrations of bone resorption marker C-terminal telopeptides of type 1 collagen (CTx-1) and bone turnover marker serum osteocalcin (OC) concentrations in the OVX group compared to control sheep. The combination of ovariectomy and glucocorticoid treatment increased the concentrations of CTx-1 and decreased serum OC concentrations in the OVXG group compared to OVXG2. Femur and lumbar spine bone density were lower in experimentally treated groups when compared with the control group. Total and trabecular vBMD in the proximal tibia were significantly lower in the treatment groups when compared with the control group. A significant negative correlation between femoral bone density and CTx-1 was found. The results of this study suggest that the combination of OVX and glucocorticoids induces bone loss in a short period of time in sheep.

17.
Nutrients ; 10(7)2018 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-30041482

RESUMO

The development and maturation of the neonatal intestine is generally influenced by diet and commensal bacteria, the composition of which, in turn, can be influenced by the diet. Colonisation of the neonatal intestine by probiotic Lactobacillus strains can strengthen, preserve, and improve barrier integrity, and adherence of probiotics to the intestinal epithelium can be influenced by the available carbon sources. The goal of the present study was to examine the role of probiotic lactobacilli strains alone or together with a carbohydrate fraction (CF) from caprine milk on barrier integrity of a co-culture model of the small intestinal epithelium. Barrier integrity (as measured by trans epithelial electrical resistance (TEER)), was enhanced by three bacteria/CF combinations (Lactobacillus rhamnosus HN001, L. plantarum 299v, and L. casei Shirota) to a greater extent than CF or bacteria alone. Levels of occludin mRNA were increased for all treatments compared to untreated co-cultures, and L. plantarum 299v in combination with CF had increased mRNA levels of MUC4, MUC2 and MUC5AC mucins and MUC4 protein abundance. These results indicate that three out of the four probiotic bacteria tested, in combination with CF, were able to elicit a greater increase in barrier integrity of a co-culture model of the small intestinal epithelium compared to that for either component alone. This study provides additional insight into the individual or combined roles of microbe⁻diet interactions in the small intestine and their beneficial contribution to the intestinal barrier.


Assuntos
Metabolismo dos Carboidratos , Carboidratos/química , Células Epiteliais/metabolismo , Lactobacillus/metabolismo , Leite/química , Probióticos/metabolismo , Animais , Células CACO-2 , Técnicas de Cocultura , Cabras , Células HT29 , Humanos , RNA Mensageiro
18.
Artigo em Inglês | MEDLINE | ID: mdl-29710852

RESUMO

Insulin resistance (IR) is accompanied by increased areal or volumetric bone mineral density (aBMD or vBMD), but also higher fracture risk. Meanwhile, imbalances in bone health biomarkers affect insulin production. This study investigates the effect of IR on proximal femur and lumbar spine BMD, femoral neck bending, compressive and impact strength indices (Composite Strength Indices) and circulating levels of parathyroid hormone (PTH), C-telopeptide of Type I collagen (CTx-1) and 25(OH) Vitamin D3, in a cohort of 97 healthy, non-obese, menopausal Chinese-Singaporean women. Lumbar spine aBMD was inversely associated with IR and dependent on lean body mass (LBM) and age. No such associations were found for vBMD of the third lumbar vertebra, aBMD and vBMD of the proximal femur, or circulating levels of PTH, CTx-1 and 25(OH) Vitamin D3. Composite Strength Indices were inversely associated with IR and independent of LBM, but after adjusting for fat mass and age, this association remained valid only for the impact strength index. Composite Strength Indices were significantly lower in participants with a high degree of IR. Our findings on IR and Composite Strength Indices relationships were in agreement with previous studies on different cohorts, but those on IR and BMD associations were not.


Assuntos
Densidade Óssea/fisiologia , Remodelação Óssea/fisiologia , Colágeno Tipo I/sangue , Resistência à Insulina/fisiologia , Menopausa/fisiologia , Peptídeos/sangue , Idoso , Colecalciferol/sangue , Feminino , Fêmur/metabolismo , Humanos , Vértebras Lombares , Pessoa de Meia-Idade , Hormônio Paratireóideo/sangue
19.
Artigo em Inglês | MEDLINE | ID: mdl-29789485

RESUMO

The diagnosis of osteoporosis is mainly based on clinical examination and bone mineral density assessments. The present pilot study compares the plasma lipid and polar metabolite profiles in blood plasma of 95 Singaporean-Chinese (SC) menopausal women with normal and low bone mineral density (BMD) using an untargeted metabolomic approach. The primary finding of this study was the association between lipids and femoral neck BMD in SC menopausal women. Twelve lipids were identified to be associated with low BMD by the orthogonal partial least squares (OPLS) model. Plasma concentrations of eight glycerophospholipid, glycerolipid, and sphingolipid species were significantly lower in menopausal women with low BMD but higher in two glycerophospholipid species (phosphatidylinositol and phosphatidic acid). Further, this study found no significant differences in plasma amino acid metabolites. However, trends for lower 4-aminobutyric acid, turanose, proline, aminopropionitrile, threonine, and methionine were found in women with low BMD. This pilot study identified associations between lipid metabolism and femoral neck BMD in SC women. Further studies are required on larger populations for evaluating the bone health effect of these compounds and their usefulness as clinical biomarkers for osteoporosis prediction in women.


Assuntos
Aminoácidos/sangue , Densidade Óssea , Lipídeos/sangue , Osteoporose Pós-Menopausa/diagnóstico , Idoso , Grupo com Ancestrais do Continente Asiático , Biomarcadores/sangue , Estudos de Casos e Controles , China/etnologia , Feminino , Humanos , Metabolômica , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/sangue , Osteoporose Pós-Menopausa/etnologia , Projetos Piloto , Singapura
20.
Appl Environ Microbiol ; 84(15)2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29802187

RESUMO

Starches resistant to mammalian digestion are present in foods and pass to the large bowel, where they may be degraded and fermented by the microbiota. Increases in relative abundances of bifidobacteria (blooms) have been reported in rats whose diet was supplemented with Hi-Maize resistant starch. We determined that the bifidobacterial species present in the rat cecum under these circumstances mostly belonged to Bifidobacterium animalis However, cultures of B. animalis isolated from the rats failed to degrade Hi-Maize starch to any extent. In contrast, Bifidobacterium pseudolongum also detected in the rat microbiota had high starch-degrading ability. Transcriptional comparisons showed increased expression of a type 1 pullulanase, alpha-amylase, and glycogen debranching enzyme by B. pseudolongum when cultured in medium containing Hi-Maize starch. Maltose was released into the culture medium, and B. animalis cultures had shorter doubling times in maltose medium than did B. pseudolongum Thus, B. pseudolongum, which was present at a consistently low abundance in the microbiota, but which has extensive enzymatic capacity to degrade resistant starch, showed the attributes of a keystone species associated with the bifidobacterial bloom.IMPORTANCE This study addresses the microbiology and function of a natural ecosystem (the rat gut) using DNA-based observations and in vitro experimentation. The microbial community of the large bowel of animals, including humans, has been studied extensively through the use of high-throughput DNA sequencing methods and advanced bioinformatics analysis. These studies reveal the compositions and genetic capacities of microbiotas but not the intricacies of how microbial communities function. Our work, combining DNA sequence analysis and laboratory experiments with cultured strains of bacteria, revealed that the increased abundance of bifidobacteria in the rat gut, induced by feeding indigestible starch, involved a species that cannot itself degrade the starch (Bifidobacterium animalis) but cohabits with a species that can (Bifidobacterium pseudolongum). B. pseudolongum has the characteristics of a keystone species in the community because it had low abundance but high ability to perform a critical function, the hydrolysis of resistant starch.


Assuntos
Bifidobacterium/isolamento & purificação , Ceco/microbiologia , Ratos/metabolismo , Amido/metabolismo , Zea mays/metabolismo , Ração Animal/análise , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bifidobacterium/classificação , Bifidobacterium/genética , Bifidobacterium/metabolismo , Ceco/metabolismo , Microbioma Gastrointestinal , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Ratos/microbiologia , alfa-Amilases/genética , alfa-Amilases/metabolismo
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