Bioaminergic Responses in an In Vitro System Studying Human Gut Microbiota-Kiwifruit Interactions.

Whole kiwifruit ('Hayward' and 'Zesy002') were examined for their bioaminergic potential after being subjected to in vitro gastrointestinal digestion and colonic fermentation. Controls included the prebiotic inulin and water, a carbohydrate-free vehicle. The dopamine precursor l-dihydroxyphenylalanine (L-DOPA) and the serotonin precursor 5-hydroxytryptophan were increased in the kiwifruit gastrointestinal digesta ('Hayward' > 'Zesy002') in comparison to the water digesta. Fermentation of the digesta with human fecal bacteria for 18 h modulated the concentrations of bioamine metabolites. The most notable were the significant increases in L-DOPA ('Zesy002' > 'Hayward') and γ-aminobutyric acid (GABA) ('Hayward' > 'Zesy002'). Kiwifruit increased Bifidobacterium spp. and Veillonellaceae (correlating with L-DOPA increase), and Lachnospira spp. (correlating with GABA). The digesta and fermenta were incubated with Caco-2 cells for 3 h followed by gene expression analysis. Effects were seen on genes related to serotonin synthesis/re-uptake/conversion to melatonin, gut tight junction, inflammation and circadian rhythm with different digesta and fermenta from the four treatments. These indicate potential effects of the substrates and the microbially generated organic acid and bioamine metabolites on intestinal functions that have physiological relevance. Further studies are required to confirm the potential bioaminergic effects of gut microbiota-kiwifruit interactions.

Influence of kiwifruit on gastric and duodenal inflammation-related gene expression in aspirin-induced gastric mucosal damage in rats.

Kiwifruit (KF) contains bioactive compounds with potential anti-inflammatory properties. In this study, we investigated the protective effects of KF on gastric and duodenal damage induced by soluble aspirin in healthy rats. Sixty-four male Sprague Dawley rats were allocated to eight experimental treatments (n = 8) and the experimental diets were fed for 14 days ad libitum. The experimental diets were 20% fresh pureed KF (green-fleshed and gold-fleshed) or 10% glucose solution (control diet). A positive anti-inflammatory control treatment (ranitidine) was included. At the end of the 14-day feeding period, the rats were fasted overnight, and the following morning soluble aspirin (400 mg/kg aspirin) or water (control) was administered by oral gavage. Four hours after aspirin administration, the rats were euthanized and samples taken for analysis. We observed no significant ulcer formation or increase in infiltration of the gastric mucosal inflammatory cells in the rats with the aspirin treatment. Despite this, there were significant changes in gene expression, such as in the duodenum of aspirin-treated rats fed green KF where there was increased expression of inflammation-related genes NOS2 and TNF-alpha. We also observed that gold and green KF diets had a number of contrasting effects on genes related to inflammation and gastro-protective effects.

Microbiota Composition of Breast Milk from Women of Different Ethnicity from the Manawatu-Wanganui Region of New Zealand.

Human breastmilk components, the microbiota and immune modulatory proteins have vital roles in infant gut and immune development. In a population of breastfeeding women (n = 78) of different ethnicities (Asian, Maori and Pacific Island, New Zealand European) and their infants living in the Manawatu-Wanganui region of New Zealand, we examined the microbiota and immune modulatory proteins in the breast milk, and the fecal microbiota of mothers and infants. Breast milk and fecal samples were collected over a one-week period during the six to eight weeks postpartum. Breast milk microbiota differed between the ethnic groups. However, these differences had no influence on the infant's gut microbiota composition. Based on the body mass index (BMI) classifications, the mother's breast milk and fecal microbiota compositions were similar between normal, overweight and obese individuals, and their infant's fecal microbiota composition also did not differ. The relative abundance of bacteria belonging to the Bacteroidetes phylum was higher in feces of infants born through vaginal delivery. However, the bacterial abundance of this phylum in the mother's breast milk or feces was similar between women who delivered vaginally or by cesarean section. Several immune modulatory proteins including cytokines, growth factors, and immunoglobulin differed between the BMI and ethnicity groups. Transforming growth factor beta 1 and 2 (TGFß1, TGFß2) were present in higher concentrations in the milk from overweight mothers compared to those of normal weight. The TGFß1 and soluble cluster of differentiation 14 (sCD14) concentrations were significantly higher in the breast milk from Maori and Pacific Island women compared with women from Asian and NZ European ethnicities. This study explores the relationship between ethnicity, body mass index, mode of baby delivery and the microbiota of infants and their mothers and their potential impact on infant health.

The Effects on Immune Function and Digestive Health of Consuming the Skin and Flesh of Zespri® SunGold Kiwifruit (Actinidia Chinensis var. Chinensis 'Zesy002') in Healthy and IBS-Constipated Individuals.

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that results in constipation (IBS-C) or diarrhoea with abdominal pain, flatulence, nausea and bloating. Kiwifruit (Actinidia spp.) are nutrient-dense fruit with a number of reported health benefits that include lowering glycaemic response, improving cardiovascular and inflammatory biomarkers, and enhancing gut comfort and laxation. This study investigated the effect of consuming three whole Zespri® SunGold kiwifruit (Actinidia chinensis var. chinensis 'Zesy002') with or without skin on cytokine production and immune and gut health in healthy people and those with IBS-C symptoms. This study enrolled thirty-eight participants in a 16 week randomized cross-over study (19 healthy and 19 participants with IBS-C). Participants were randomized to consume either three kiwifruit without eating the skin or three kiwifruit including the skin for 4 weeks each, with a 4 week washout in between each intervention. There was a significant decrease in the pro-inflammatory cytokine, TNF-α, for both the healthy and the IBS-C participants when they consumed whole kiwifruit and skin, and also for the healthy participants when they ate whole kiwifruit without the skin (p < 0.001). The kiwifruit interventions increased bowel frequency and significantly reduced the gastrointestinal symptom rating scale constipation and Birmingham IBS pain scores for both participant groups. We have demonstrated that consuming the skin of SunGold kiwifruit might have beneficial effects on gastrointestinal health that are not produced by consuming the flesh alone.

Mechanisms of Selenium Enrichment and Measurement in Brassicaceous Vegetables, and Their Application to Human Health.

Selenium (Se) is an essential micronutrient for human health. Se deficiency affects hundreds of millions of people worldwide, particularly in developing countries, and there is increasing awareness that suboptimal supply of Se can also negatively affect human health. Selenium enters the diet primarily through the ingestion of plant and animal products. Although, plants are not dependent on Se they take it up from the soil through the sulphur (S) uptake and assimilation pathways. Therefore, geographic differences in the availability of soil Se and agricultural practices have a profound influence on the Se content of many foods, and there are increasing efforts to biofortify crop plants with Se. Plants from the Brassicales are of particular interest as they accumulate and synthesize Se into forms with additional health benefits, such as methylselenocysteine (MeSeCys). The Brassicaceae are also well-known to produce the glucosinolates; S-containing compounds with demonstrated human health value. Furthermore, the recent discovery of the selenoglucosinolates in the Brassicaceae raises questions regarding their potential bioefficacy. In this review we focus on Se uptake and metabolism in the Brassicaceae in the context of human health, particularly cancer prevention and immunity. We investigate the close relationship between Se and S metabolism in this plant family, with particular emphasis on the selenoglucosinolates, and consider the methodologies available for identifying and quantifying further novel Se-containing compounds in plants. Finally, we summarize the research of multiple groups investigating biofortification of the Brassicaceae and discuss which approaches might be most successful for supplying Se deficient populations in the future.

Influence of Dietary Avocado on Gut Health in Rats.

This study investigated the impact of diets containing various levels of avocado (5, 10 and 15%) on gut health in rats fed for six weeks. Avocado-fed rats had significantly higher food intakes while their body weights remained similar to the control diet-fed rats. No significant changes in intestinal bacterial populations (ileum, cecum and colon) were found in rats fed avocado diets compared to the control diet. Ileum and colon tissues of rats fed avocado diets showed significantly higher expression of genes (ß-defensin 1, mucin 3 or mucin 4) and a greater number of mucin-producing goblet cells in the colon. The percentage of avocado in the diet had varying effects in altering the biomarkers, whereby diet containing 15% avocado was the more effective diet. This study delivers new knowledge on the role of avocado on gut health in rats.

Comparison of quantitative real-time polymerase chain reaction with NanoString® methodology using adipose and liver tissues from rats fed seaweed.

Experimental methods are constantly being improved by new technology. Recently a new technology, NanoString®, has been introduced to the market for the analysis of gene expression. Our experiments used adipose and liver samples collected from a rat feeding trial to explore gene expression changes resulting from a diet of 7.5% seaweed. Both quantitative real-time polymerase chain reaction (qPCR) and NanoString methods were employed to look at expression of genes related to fat and glucose metabolism and this paper compares results from both methods. We conclude that NanoString offers a valuable alternative to qPCR and our data suggest that results are more accurate because of the reduced sample handling and direct quantification of gene copy number without the need for enzymatic amplification. However, we have highlighted a potential challenge for both methods, which needs to be addressed when designing primers or probes. We suggest a literature search for known splice variants of a particular gene to be completed so that primers or probes can be designed that do not span exons which may be affected by alternative gene sequences.

Consumption of selenium-enriched broccoli increases cytokine production in human peripheral blood mononuclear cells stimulated ex vivo, a preliminary human intervention study.

SCOPE: Selenium (Se) is a micronutrient essential for human health, including immune function. Previous research indicates that Se supplementation may cause a shift from T helper (Th)1- to Th2-type immune responses. We aim to test the potential health promoting effects of Se-enriched broccoli. METHODS AND RESULTS: In a human trial, 18 participants consumed control broccoli daily for 3 days. After a 3-day wash-out period, the participants were provided with Se-enriched broccoli containing 200 µg of Se per serving for 3 days. Plasma and peripheral blood mononuclear cell (PBMC) samples were collected at the start and end of each broccoli feeding period for analysis of total Se and measurement of cytokine production from PBMC stimulated with antigens ex vivo. Plasma Se content remained consistent throughout the control broccoli feeding period and the baseline of the Se-enriched broccoli period (1.22 µmol/L) and then significantly increased following 3 days of Se-enriched broccoli feeding. Interleukin (IL-2, IL-4, IL-5, IL-13, and IL-22) production from PBMC significantly increased after 3 days of Se-enriched broccoli feeding compared with baseline. CONCLUSION: This study indicates that consumption of Se-enriched broccoli may increase immune responses toward a range of immune challenges.

Influence of green and gold kiwifruit on indices of large bowel function in healthy rats.

The effects of kiwifruit on large bowel health were investigated in healthy rats. Four-week old Sprague-Dawley rats were given diets containing 10% homogenized green kiwifruit, gold kiwifruit or 10% glucose solution (control) over 4 or 6 wk. Green kiwifruit increased the fecal output compared to control. Growth of certain bacterial species in cecum was influenced by both green and gold kiwifruit. A significant increase in cecal Lachnospiraceae in rats fed the green kiwifruit diet was observed at week 4. At week 6, green and gold kiwifruit diets assisted in improving colonic barrier function by upregulating the expression of mucin (MUC)-2, MUC3, Toll-like receptor (TLR)-4 or trefoil factor-3 genes. Gold kiwifruit consumption increased the colonic goblet cells per crypt at week 6. Significant negative correlations between E. coli and ß-defensin 1 and TLR4 expression were observed. Consuming green and gold kiwifruit for 6 wk significantly altered the biomarkers of large bowel health; indicating that regularly consuming kiwifruit helps attain optimal digestive health.

Apple polyphenol extracts protect against aspirin-induced gastric mucosal damage in rats.

The protective role of two apple polyphenol extracts, Douglas-FB (FB) and Douglas-EF (EF), on gastric mucosal damage following aspirin ingestion was investigated in healthy rats. Polyphenol content of the apple extracts varied, with the EF extract having 20% w/w polyphenols and a high proportion of flavanols as epicatechin and procyanidin, whereas the FB extract comprised 12% w/w polyphenols, which were mostly flavonols as quercetin glycosides. Male Sprague-Dawley rats were allocated to control, FB and EF groups and fed the experimental diet during the 10-day trial. Control treatment rats received 1 mL of deionised water, whereas apple polyphenol treatment group rats, FB and EF received a concentration of 10(-2) m polyphenols in 1 mL deionised water daily via oral gavage. At the end of 10-day feeding period, rats were fasted overnight, and the following morning, aspirin (200 mg/kg) was given by oral gavage. Four hours after aspirin administration, the animals were euthanised, and samples taken for analysis. Both apple polyphenol extracts significantly reduced the ulcer area, ulcer lesion index and gastric injury score. The glutathione in gastric mucosa was increased significantly in rats given FB apple extract. Despite their different polyphenol compositions, FB and EF apple extracts assisted in protecting the gastric mucosa following acute aspirin administration in rats.

Polyunsaturated fatty acids modify expression of TGF-ß in a co-culture model ultilising human colorectal cells and human peripheral blood mononuclear cells exposed to Lactobacillus gasseri, Escherichia coli and Staphylococcus aureus.

Commensal bacteria and polyunsaturated fatty acids (PUFAs) have both been shown independently to modulate immune responses. This study tested the hypothesis that the different colonic immunomodulatory responses to commensal (Lactobacillus gasseri) and pathogenic bacteria (Escherichia coli and Staphylococcus aureus) may be modified by PUFAs. Experiments used a Transwell system combining the colorectal cell line HT29, or its mucous secreting sub-clone HT29-MTX, with peripheral blood mononuclear cells to analyse immunomodulatory signalling in response to bacteria, with and without prior treatment with arachidonic acid, eicosapentaenoic acid or docosahexaenoic acid. L. gasseri increased transforming growth factor ß1 (TGF-ß1) mRNA and protein secretion in colonic cell lines when compared with controls, an effect that was enhanced by pre-treatment with eicosapentaenoic acid. In contrast, the Gram-negative pathogen E. coli LF82 had no significant effect on TGF-ß1 protein. L. gasseri also increased IL-8 mRNA but not protein while E. coli increased both; although differences between PUFA treatments were detected, none were significantly different to controls. Colonic epithelial cells show different immunomodulatory signalling patterns in response to the commensal L. gasseri compared to E. coli and S. aureus and pre-treatment of these cells with PUFAs can modify responses. Practical applications: We have demonstrated an interaction between dietary PUFAs and epithelial cell response to both commensal and pathogenic bacteria found in the gastrointestinal tract by utilising in vitro co-culture models. The data suggest that n-3 PUFAs may provide some protection against the potentially damaging effects of pathogens. Furthermore, the beneficial effects of combining n-3 PUFAs and the commensal bacteria, and potential probiotic, L. gasseri are illustrated by the increased expression of immunoregulatory TGF-ß1.

Digested and fermented green kiwifruit increases human ß-defensin 1 and 2 production in vitro.

The intestinal mucosa is constantly exposed to a variety of microbial species including commensals and pathogens, the latter leaving the host susceptible to infection. Antimicrobial peptides (AMP) are an important part of the first line of defense at mucosal surfaces. Human ß-defensins (HBD) are AMP expressed by colonic epithelial cells, which act as broad spectrum antimicrobials. This study explored the direct and indirect effects of green kiwifruit (KF) on human ß-defensin 1 and 2 (HBD-1 and 2) production by epithelial cells. In vitro digestion of KF pulp consisted of a simulated gastric and duodenal digestion, followed by colonic microbial fermentation using nine human faecal donors. Fermenta from individual donors was sterile filtered and independently added to epithelial cells prior to analysis of HBD protein production. KF products obtained from the gastric and duodenal digestion had no effect on the production of HBD-1 or 2 by epithelial cells, demonstrating that KF does not contain substances that directly modulate defensin production. However, when the digested KF products were further subjected to in vitro colonic fermentation, the fermentation products significantly up-regulated HBD-1 and 2 production by the same epithelial cells. We propose that this effect was predominantly mediated by the presence of short-chain fatty acids (SCFA) in the fermenta. Exposure of cells to purified SCFA confirmed this and HBD-1 and 2 production was up-regulated with acetate, propionate and butyrate. In conclusion, in vitro colonic fermentation of green kiwifruit digest appears to prime defense mechanisms in gut cells by enhancing the production of antimicrobial defensins.