Divergent selection for feed efficiency in pigs altered the duodenum transcriptomic response to feed intake and its DNA methylation profiles

Feed efficiency is a trait of interest in pigs as it contributes to lowering the ecological and economical costs of pig production. A divergent genetic selection experiment from a Large White pig population was performed for 10 generations, leading to pig lines with relatively low- (LRFI) and high- (HRFI) residual feed intake (RFI). Feeding behavior and metabolic differences have been previously reported between the two lines. We hypothesized that part of these differences could be related to differential sensing and absorption of nutrients in the proximal intestine. We investigated the duodenum transcriptome and DNA methylation profiles comparing overnight fasting with ad libitum feeding in LRFI and HRFI pigs (n = 24). We identified 1,106 differentially expressed genes between the two lines, notably affecting pathways of the transmembrane transport activity and related to mitosis or chromosome separation. The LRFI line showed a greater transcriptomic response to feed intake than the HRFI line. Feed intake affected genes from both anabolic and catabolic pathways in the pig duodenum, such as rRNA production and autophagy. Several nutrient transporter and tight junction genes were differentially expressed between lines and/or by short-term feed intake. We also identified 409 differentially methylated regions in the duodenum mucosa between the two lines, while this epigenetic mark was less affected by feeding. Our findings highlighted that the genetic selection for feed efficiency in pigs changed the transcriptome profiles of the duodenum, and notably its response to feed intake, suggesting key roles for this proximal gut segment in mechanisms underlying feed efficiency.NEW & NOTEWORTHY The duodenum is a key organ for the hunger/satiety loop and nutrient sensing. We investigated how the duodenum transcriptome and DNA methylation profiles are affected by feed intakes in pigs. We observed thousands of changes in gene expression levels between overnight-fasted and fed pigs in high-feed efficiency pig lines, but almost none in the related low-feed efficiency pig line.

BEST4+ cells in the intestinal epithelium

The recent development of single-cell transcriptomics highlighted the existence of a new lineage of mature absorptive cells in the human intestinal epithelium. This subpopulation is characterized by the specific expression of Bestrophin 4 (BEST4) and of other marker genes including OTOP2, CA7, GUCA2A, GUCA2B, and SPIB. BEST4+ cells appear early in development and are present in all regions of the small and large intestine at a low abundance (<5% of all epithelial cells). Location-specific gene expression profiles in BEST4+ cells suggest their functional specialization in each gut region, as exemplified by the small intestine-specific expression of the ion channel CFTR. The putative roles of BEST4+ cells include sensing and regulation of luminal pH, tuning of guanylyl cyclase-C signaling, transport of electrolytes, hydration of mucus, and secretion of antimicrobial peptides. However, most of these hypotheses lack functional validation, notably because BEST4+ cells are absent in mice. The presence of BEST4+ cells in human intestinal organoids indicates that this in vitro model should be suitable to study their role. Recent studies showed that BEST4+ cells are also present in the intestinal epithelium of macaque, pig, and zebrafish and, here, we report their presence in rabbits, which suggests that these species could be appropriate animal models to study BEST4+ cells during the development of diseases and their interactions with environmental factors such as diet or the microbiota. In this review, we summarize the existing literature regarding BEST4+ cells and emphasize the description of their predicted roles in the intestinal epithelium in health and disease.NEW & NOTEWORTHY BEST4+ cells are a novel subtype of mature absorptive cells in the human intestinal epithelium highlighted by single-cell transcriptomics. The gene expression profile of BEST4+ cells suggests their role in pH regulation, electrolyte secretion, mucus hydration, and innate immune defense. The absence of BEST4+ cells in mice requires the use of alternative animal models or organoids to decipher the role of this novel type of intestinal epithelial cells.

Coprophagia in early life tunes expression of immune genes after weaning in rabbit ileum

Coprophagia by suckling rabbits, i.e. ingestion of feces from their mother, reduces mortality after weaning. We hypothesized that this beneficial effect of coprophagia is immune-mediated at the intestinal level. Therefore, this study investigated immune development after weaning by analyzing the ileal transcriptome at day 35 and 49 in rabbits with differential access to coprophagia in early life. Rabbit pups had access between day 1 and 15 to (i) no feces (NF) or (ii) feces from unrelated does (Foreign Feces, FF) or (iii) feces from unrelated does treated with antibiotics (FFab). 350 genes were differentially expressed between day 35 and day 49 in suckling rabbits with access to coprophagia. These genes coded for antimicrobial peptides, a mucin, cytokines and chemokines, pattern recognition receptors, proteins involved in immunoglobulin A secretion and in interferon signaling pathway. Strikingly, prevention of coprophagia or access to feces from antibiotic-treated does in early life blunted immune development between day 35 et 49 in the ileum of rabbits. Thus, coprophagia might be crucial for the maturation of intestinal immunity in rabbits and could explain why this behavior improves survival.

Evaluation of utero-placental vascularization using contrast-enhanced ultrasound: Early first trimester maternal perfusion of the intervillous space is confirmed

INTRODUCTION

The objective was to confirm and semiquantify the maternal perfusion of the intervillous space between 8 and 13 + 6 gestational weeks (GW).

METHODS

We conducted a prospective, multicenter, and nonrandomized open study. Women undergoing voluntary termination of pregnancy at three different gestational ages (Group 8 GW: 8 to 8 + 6 GW, Group 11GW: 11 to 11 + 6 GW and Group 13GW: 13 to 13 + 6 GW) were included, with 14 subjects per group. Women presenting with a personal risk of preeclampsia and/or intrauterine growth restriction were excluded. Contrast-enhanced ultrasound (CEUS) was performed with an intravenous bolus administration of 2.4 mL of microbubbles. The region of interest (ROI) was the entire placenta. The perfusion curves and kinetic parameters, including wash-in perfusion index, peak enhancement and mean transit time, were calculated.

RESULTS

Of the 42 women initially included, interpretable perfusion curves could be obtained for 33. Regardless of the gestational age, contrast was observed in the entire placenta. No significant difference in perfusion parameters was observed between groups. There was an association between signal intensity and both maternal heart frequency and placental location. Signal intensity was decreased when the heart frequency increased (p < 0.05) and when the placenta was in a nonanterior position (p > 0.005).

DISCUSSION

We confirmed the presence of maternal perfusion of the intervillous space as early as 8 GW. No significant increase in perfusion parameters was observed between 8 and 13 + 6 GW. Our observations, in accordance with the previous experiment published by Roberts et al.1, strongly challenge the classic trophoblastic plug theory.

Effect of diet supplemented with functional amino acids and polyphenols on gut health in broilers subjected to a corticosterone-induced stress

To address the overuse of antimicrobials in poultry production, new functional feed ingredients, i.e. ingredients with benefits beyond meeting basic nutritional requirements, can play a crucial role thanks to their prophylactic effects. This study evaluated the effects of the supplementation of arginine, threonine and glutamine together with grape polyphenols on the gut integrity and functionality of broilers facing a stress condition. 108 straight-run newly hatched Ross PM3 chicks were kept until 35 days and were allocated to 3 treatments. Broilers in the control group were raised in standard conditions. In experimental groups, birds were administered with corticosterone in drinking water (CORT groups) to impair the global health of the animal and were fed a well-balanced diet supplemented or not with a mix of functional amino acids together with grape extracts (1 g/kg of diet-CORT + MIX group). Gut permeability was significantly increased by corticosterone in non-supplemented birds. This corticosterone-induced stress effect was alleviated in the CORT + MIX group. MIX supplementation attenuated the reduction of crypt depth induced by corticosterone. Mucin 2 and TNF-α gene expression was up-regulated in the CORT + MIX group compared to the CORT group. Caecal microbiota remained similar between the groups. These findings indicate that a balanced diet supplemented with functional AA and polyphenols can help to restore broiler intestinal barrier after a stress exposure.

Disruption of the primocolonizing microbiota alters epithelial homeostasis and imprints stem cells in the colon of neonatal piglets

The gut microbiota plays a key role in the postnatal development of the intestinal epithelium. However, the bacterial members of the primocolonizing microbiota driving these effects are not fully identified and the mechanisms underlying their long-term influence on epithelial homeostasis remain poorly described. Here, we used a model of newborn piglets treated during the first week of life with the antibiotic colistin in order to deplete specific gram-negative bacteria that are transiently dominant in the neonatal gut microbiota. Colistin depleted Proteobacteria and Fusobacteriota from the neonatal colon microbiota, reduced the bacterial predicted capacity to synthetize lipopolysaccharide (LPS), and increased the concentration of succinate in the colon. The colistin-induced disruption of the primocolonizing microbiota was associated with altered gene expression in the colon epithelium including a reduction of toll-like receptor 4 (TLR4) and lysozyme (LYZ). Our data obtained in porcine colonic organoid cell monolayers suggested that these effects were not driven by the variation of succinate or LPS levels nor by a direct effect of colistin on epithelial cells. The disruption of the primocolonizing microbiota imprinted colon epithelial stem cells since the expression of TLR4 and LYZ remained lower in organoids derived from colistin-treated piglet colonic crypts after several passages when compared to control piglets. Finally, the stable imprinting of LYZ in colon organoids was independent of the H3K4me3 level in its transcription start site. Altogether, our results show that disruption of the primocolonizing gut microbiota alters epithelial innate immunity in the colon and imprints stem cells, which could have long-term consequences for gut health.

The Early Life Microbiota Is Not a Major Factor Underlying the Susceptibility to Postweaning Diarrhea in Piglets

Postweaning diarrhea (PWD) in piglets impair welfare, induce economic losses and lead to overuse of antibiotics. The early life gut microbiota was proposed to contribute to the susceptibility to PWD. The objective of our study was to evaluate in a large cohort of 116 piglets raised in 2 separate farms whether the gut microbiota composition and functions during the suckling period were associated with the later development of PWD. The fecal microbiota and metabolome were analyzed by 16S rRNA gene amplicon sequencing and nuclear magnetic based resonance at postnatal day 13 in male and female piglets. The later development of PWD was recorded for the same animals from weaning (day 21) to day 54. The gut microbiota structure and α-diversity during the suckling period were not associated with the later development of PWD. There was no significant difference in the relative abundances of bacterial taxa in suckling piglets that later developed PWD. The predicted functionality of the gut microbiota and the fecal metabolome signature during the suckling period were not linked to the later development of PWD. Trimethylamine was the bacterial metabolite which fecal concentration during the suckling period was the most strongly associated with the later development of PWD. However, experiments in piglet colon organoids showed that trimethylamine did not disrupt epithelial homeostasis and is thus not likely to predispose to PWD through this mechanism. In conclusion, our data suggest that the early life microbiota is not a major factor underlying the susceptibility to PWD in piglets. IMPORTANCE This study shows that the fecal microbiota composition and metabolic activity are similar in suckling piglets (13 days after birth) that either later develop post-weaning diarrhea (PWD) or not, which is a major threat for animal welfare that also causes important economic losses and antibiotic treatments in pig production. The aim of this work was to study a large cohort of piglets raised in separates environments, which is a major factor influencing the early life microbiota. One of the main findings is that, although the fecal concentration of trimethylamine in suckling piglets was associated with the later development of PWD, this gut microbiota-derived metabolite did not disrupt the epithelial homeostasis in organoids derived from the pig colon. Overall, this study suggests that the gut microbiota during the suckling period is not a major factor underlying the susceptibility of piglets to PWD.

Obesogenic diet leads to luminal overproduction of the complex IV inhibitor H2 S and mitochondrial dysfunction in mouse colonocytes

Obesity is characterized by systemic low-grade inflammation associated with disturbances of intestinal homeostasis and microbiota dysbiosis. Mitochondrial metabolism sustains epithelial homeostasis by providing energy to colonic epithelial cells (CEC) but can be altered by dietary modulations of the luminal environment. Our study aimed at evaluating whether the consumption of an obesogenic diet alters the mitochondrial function of CEC in mice. Mice were fed for 22 weeks with a 58% kcal fat diet (diet-induced obesity [DIO] group) or a 10% kcal fat diet (control diet, CTRL). Colonic crypts were isolated to assess mitochondrial function while colonic content was collected to characterize microbiota and metabolites. DIO mice developed obesity, intestinal hyperpermeability, and increased endotoxemia. Analysis of isolated colonic crypt bioenergetics revealed a mitochondrial dysfunction marked by decreased basal and maximal respirations and lower respiration linked to ATP production in DIO mice. Yet, CEC gene expression of mitochondrial respiration chain complexes and mitochondrial dynamics were not altered in DIO mice. In parallel, DIO mice displayed increased colonic bile acid concentrations, associated with higher abundance of Desulfovibrionaceae. Sulfide concentration was markedly increased in the colon content of DIO mice. Hence, chronic treatment of CTRL mouse colon organoids with sodium sulfide provoked mitochondrial dysfunction similar to that observed in vivo in DIO mice while acute exposure of isolated mitochondria from CEC of CTRL mice to sodium sulfide diminished complex IV activity. Our study provides new insights into colon mitochondrial dysfunction in obesity by revealing that increased sulfide production by DIO-induced dysbiosis impairs complex IV activity in mouse CEC.

Culture of Piglet Intestinal 3D Organoids from Cryopreserved Epithelial Crypts and Establishment of Cell Monolayers

Intestinal organoids are increasingly being used to study the gut epithelium for digestive disease modeling, or to investigate interactions with drugs, nutrients, metabolites, pathogens, and the microbiota. Methods to culture intestinal organoids are now available for multiple species, including pigs, which is a species of major interest both as a farm animal and as a translational model for humans, for example, to study zoonotic diseases. Here, we give an in-depth description of a procedure used to culture pig intestinal 3D organoids from frozen epithelial crypts. The protocol describes how to cryopreserve epithelial crypts from the pig intestine and the subsequent procedures to culture 3D intestinal organoids. The main advantages of this method are (i) the temporal dissociation of the isolation of crypts from the culture of 3D organoids, (ii) the preparation of large stocks of cryopreserved crypts derived from multiple intestinal segments and from several animals at once, and thus (iii) the reduction in the need to sample fresh tissues from living animals. We also detail a protocol to establish cell monolayers derived from 3D organoids to allow access to the apical side of epithelial cells, which is the site of interactions with nutrients, microbes, or drugs. Overall, the protocols described here is a useful resource for studying the pig intestinal epithelium in veterinary and biomedical research.

[The role of the physiotherapist in the assessment and management of dyspnea]

The role of the physiotherapist in the assessment and management of dyspnea. Dyspnea is the most common symptom in cardio-respiratory diseases. Recently improved comprehension of dyspnea mechanisms have underlined the need for three-faceted assessment. The three key aspects correspond to the "breathing, thinking, functioning" clinical model, which proposes a multidimensional - respiratory, emotional and functional - approach. Before initiating treatment, it is essential for several reasons to assess each specific case, determining the type of dyspnea affecting the patient, appraising the impact of shortness of breath, and estimating the effectiveness of the treatment applied. The physiotherapist has a major role to assume in the care of dyspneic patients, not only in assessment followed by treatment but also as a major collaborator in a multidisciplinary team, especially with regard to pulmonary rehabilitation. The aim of this review is to inventory the existing assessment tools and the possible physiotherapies for dyspnea, using a holistic approach designed to facilitate the choice of techniques and to improve quality of care by fully addressing the patient's needs.

A blend of functional amino acids and grape polyphenols improves the pig capacity to cope with an inflammatory challenge caused by poor hygiene of housing conditions

BACKGROUND

Dietary supplementation with a blend of functional amino acids (AA) and grape extract polyphenols contributes to preserve intestinal health and growth performance of piglets during the post-weaning period. In the present experiment, we assessed if a supplementation with a mix of AA and grape extract polyphenols during the post-weaning period would persist to improve the pig capacity to cope with a subsequent challenge caused by poor hygiene of housing conditions. Eighty pigs weaned at 28 days of age were fed a standard diet supplemented (AAP) or not (CNT) with 0.2% of a blend of AA (glutamine, arginine, cystine, valine, isoleucine, and leucine) and grape extract polyphenols during the post-weaning period (from week 0 to 6). At week 6, pigs were transferred to a growing unit where 50% of pigs previously fed AAP and CNT diets were housed in good and the other 50% in poor hygiene conditions for 3 weeks (from week 7 to 9; challenge period). All pigs were fed a standard growing diet that was not supplemented with AAP. We measured pig growth performance, plasma indicators of inflammation, digestive integrity, and oxidative status, and scored fecal consistency. Differences were considered significant at P ≤ 0.05.

RESULTS

One week post-weaning, pigs fed AAP had lower plasma concentrations of haptoglobin than CNT pigs (P = 0.03). Six weeks post-weaning, plasma concentrations of diamine oxidase (DAO) were lower (P = 0.03) whereas those of vitamin E and A were greater (P ≤ 0.05) in pigs fed AAP compared to CNT pigs. The prevalence of diarrhea was higher in CNT pigs compared to AAP pigs (P < 0.01). During the challenge period, only pigs previously fed CNT diet had lower growth rate in poor than good conditions (P ≤ 0.05). They had also greater plasma concentrations of haptoglobin and oxidative stress index (OSI) and lower plasma concentrations of vitamin E in poor than good hygiene conditions (P ≤ 0.05).

CONCLUSIONS

Pigs fed AAP diet during post-weaning had less diarrhea and plasma concentrations of a digestive integrity marker, as well as greater plasma concentrations of antioxidant indicators during the post-weaning period. The beneficial effects of AAP supplementation persisted after the post-weaning period as evidenced by the absence of effects of the hygiene challenge on growth and health indicators in pigs previously fed APP. This clearly indicated a greater ability of pigs fed AAP to cope with the poor hygiene conditions.

Selective nourishing of gut microbiota with amino acids: A novel prebiotic approach?

Prebiotics are dietary substrates which promote host health when utilized by desirable intestinal bacteria. The most commonly used prebiotics are non-digestible oligosaccharides but the prebiotic properties of other types of nutrients such as polyphenols are emerging. Here, we review recent evidence showing that amino acids (AA) could function as a novel class of prebiotics based on: (i) the modulation of gut microbiota composition, (ii) the use by selective intestinal bacteria and the transformation into bioactive metabolites and (iii) the positive impact on host health. The capacity of intestinal bacteria to metabolize individual AA is species or strain specific and this property is an opportunity to favor the growth of beneficial bacteria while constraining the development of pathogens. In addition, the chemical diversity of AA leads to the production of multiple bacterial metabolites with broad biological activities that could mediate their prebiotic properties. In this context, we introduce the concept of "Aminobiotics," which refers to the functional role of some AA as prebiotics. We also present studies that revealed synergistic effects of the co-administration of AA with probiotic bacteria, indicating that AA can be used to design novel symbiotics. Finally, we discuss the difficulty to bring free AA to the distal gut microbiota and we propose potential solutions such as the use of delivery systems including encapsulation to bypass absorption in the small intestine. Future studies will need to further identify individual AA, dose and mode of administration to optimize prebiotic effects for the benefit of human and animal health.

The phenotype of the gut region is more stably retained than developmental stage in piglet intestinal organoids

Intestinal organoids are innovative in vitro tools to study the digestive epithelium. The objective of this study was to generate jejunum and colon organoids from suckling and weaned piglets in order to determine the extent to which organoids retain a location-specific and a developmental stage-specific phenotype. Organoids were studied at three time points by gene expression profiling for comparison with the transcriptomic patterns observed in crypts in vivo. In addition, the gut microbiota and the metabolome were analyzed to characterize the luminal environment of epithelial cells at the origin of organoids. The location-specific expression of 60 genes differentially expressed between jejunum and colon crypts from suckling piglets was partially retained (48%) in the derived organoids at all time point. The regional expression of these genes was independent of luminal signals since the major differences in microbiota and metabolome observed in vivo between the jejunum and the colon were not reproduced in vitro. In contrast, the regional expression of other genes was erased in organoids. Moreover, the developmental stage-specific expression of 30 genes differentially expressed between the jejunum crypts of suckling and weaned piglets was not stably retained in the derived organoids. Differentiation of organoids was necessary to observe the regional expression of certain genes while it was not sufficient to reproduce developmental stage-specific expression patterns. In conclusion, piglet intestinal organoids retained a location-specific phenotype while the characteristics of developmental stage were erased in vitro. Reproducing more closely the luminal environment might help to increase the physiological relevance of intestinal organoids.

Developmental Stage, Solid Food Introduction, and Suckling Cessation Differentially Influence the Comaturation of the Gut Microbiota and Intestinal Epithelium in Rabbits

BACKGROUND

In mammals, the establishment around weaning of a symbiotic relationship between the gut microbiota and its host determines long-term health.

OBJECTIVES

The aim of this study was to identify the factors driving the comaturation of the gut microbiota and intestinal epithelium at the suckling-to-weaning transition. We hypothesized that the developmental stage, solid food ingestion, and suckling cessation contribute to this process.

METHODS

From birth to day 18, Hyplus rabbits were exclusively suckling. From day 18 to day 25, rabbits were 1) exclusively suckling; 2) suckling and ingesting solid food; or 3) exclusively ingesting solid food. The microbiota (16S amplicon sequencing), metabolome (nuclear magnetic resonance), and epithelial gene expression (high-throughput qPCR) were analyzed in the cecum at days 18 and 25.

RESULTS

The microbiota structure and metabolic activity were modified with age when rabbits remained exclusively suckling. The epithelial gene expression of nutrient transporters, proliferation markers, and innate immune factors were also regulated with age (e.g., 1.5-fold decrease of TLR5). Solid food ingestion by suckling rabbits had a major effect on the gut microbiota by increasing its α diversity, remodeling its structure (e.g., 6.3-fold increase of Ruminococcaceae), and metabolic activity (e.g., 4.6-fold increase of butyrate). Solid food introduction also regulated the gene expression of nutrient transporters, differentiation markers, and innate immune factors in the epithelium (e.g., 3-fold increase of nitric oxide synthase). Suckling cessation had no effect on the microbiota, while it regulated the expression of genes involved in epithelial differentiation and immunoglobulin transport (e.g., 2.5-increase of the polymeric immunoglobulin receptor).

CONCLUSIONS

In rabbits, the maturation of the microbiota at the suckling-to-weaning transition is driven by the introduction of solid food and, to a lesser extent, by the developmental stage. In contrast, the maturation of the intestinal epithelium at the suckling-to-weaning transition is under the influence of the developmental stage, solid food introduction, and suckling cessation.

New insights into human functional ultrasound imaging

Ultrasound imaging is a vital tool for exploring in vivo the placental function which is essential to understand pathological phenomena such as preeclampsia or intrauterine growth restriction. As technology advances including ready availability of three-dimensional (3D) probes and novel software, new markers of placental function become possible. The objective of this review was to provide an overview of the new ultrasound markers of placental function with a focus on the potential clinical application of three-dimensional power Doppler (3DPD). A broad-free text literature search was undertaken based on human placental studies and sixty full-text studies were included in this review. Three-dimensional power Doppler is a promising technique to predict preeclampsia in the first trimester. However, the influence of external factors such as body mass index, parameter standardisation and machine settings still need to be addressed. Contrast-enhanced ultrasound is currently reserved for research, because the required injected contrast mediums are not currently approved for use in pregnancy, although the safety data is reassuring.

A mix of functional amino acids and grape polyphenols promotes the growth of piglets, modulates the gut microbiota in vivo and regulates epithelial homeostasis in intestinal organoids

Weaning is a challenging period for gut health in piglets. Previous studies showed that dietary supplementations with either amino acids or polyphenols promote piglet growth and intestinal functions, when administered separately. Thus, we hypothesized that a combination of amino acids and polyphenols could facilitate the weaning transition. Piglets received during the first two weeks after weaning a diet supplemented or not with a mix of a low dose (0.1%) of functional amino acids (L-arginine, L-leucine, L-valine, L-isoleucine, L-cystine) and 100 ppm of a polyphenol-rich extract from grape seeds and skins. The mix of amino acids and polyphenols improved growth and feed efficiency. These beneficial effects were associated with a lower microbiota diversity and a bloom of Lactobacillaceae in the jejunum content while the abundance of Proteobacteria was reduced in the caecum content. The mix of amino acids and polyphenols also increased the production by the caecum microbiota of short-chain fatty acids (butyrate, propionate) and of metabolites derived from amino acids (branched-chain fatty acids, valerate, putrescine) and from polyphenols (3-phenylpropionate). Experiments in piglet jejunum organoids revealed that the mix of amino acids and polyphenols upregulated the gene expression of epithelial differentiation markers while it reduced the gene expression of proliferation and innate immunity markers. In conclusion, the supplementation of a mix of amino acids and polyphenols is a promising nutritional strategy to manage gut health in piglets through the modulation of the gut microbiota and of the epithelial barrier.

Pathogen Challenge and Dietary Shift Alter Microbiota Composition and Activity in a Mucin-Associated in vitro Model of the Piglet Colon (MPigut-IVM) Simulating Weaning Transition

Enterotoxigenic Escherichia coli (ETEC) is the principal pathogen responsible for post-weaning diarrhea in newly weaned piglets. Expansion of ETEC at weaning is thought to be the consequence of various stress factors such as transient anorexia, dietary change or increase in intestinal inflammation and permeability, but the exact mechanisms remain to be elucidated. As the use of animal experiments raise more and more ethical concerns, we used a recently developed in vitro model of piglet colonic microbiome and mucobiome, the MPigut-IVM, to evaluate the effects of a simulated weaning transition and pathogen challenge at weaning. Our data suggested that the tested factors impacted the composition and functionality of the MPigut-IVM microbiota. The simulation of weaning transition led to an increase in relative abundance of the Prevotellaceae family which was further promoted by the presence of the ETEC strain. In contrast, several beneficial families such as Bacteroidiaceae or Ruminococcaceae and gut health related short chain fatty acids like butyrate or acetate were reduced upon simulated weaning. Moreover, the incubation of MPigut-IVM filtrated effluents with porcine intestinal cell cultures showed that ETEC challenge in the in vitro model led to an increased expression of pro-inflammatory genes by the porcine cells. This study provides insights about the etiology of a dysbiotic microbiota in post-weaning piglets.

Weaning-associated feed deprivation stress causes microbiota disruptions in a novel mucin-containing in vitro model of the piglet colon (MPigut-IVM)

BACKGROUND

Risk factors for the etiology of post-weaning diarrhea, a major problem in swine industry associated with enormous economic losses, remain to be fully elucidated. In concordance with the ethical concerns raised by animal experiments, we developed a new in vitro model of the weaning piglet colon (MPigut-IVM) including a mucin bead compartment to reproduce the mucus surface from the gut to which gut microbes can adhere.

RESULTS

Our results indicated that the MPigut-IVM is able to establish a representative piglet archaeal and bacterial colon microbiota in terms of taxonomic composition and function. The MPigut-IVM was consequently used to investigate the potential effects of feed deprivation, a common consequence of weaning in piglets, on the microbiota. The lack of nutrients in the MPigut-IVM led to an increased abundance of Prevotellaceae and Escherichia-Shigella and a decrease in Bacteroidiaceae and confirms previous in vivo findings. On top of a strong increase in redox potential, the feed deprivation stress induced modifications of microbial metabolite production such as a decrease in acetate and an increase in proportional valerate, isovalerate and isobutyrate production.

CONCLUSIONS

The MPigut-IVM is able to simulate luminal and mucosal piglet microbiota and represent an innovative tool for comparative studies to investigate the impact of weaning stressors on piglet microbiota. Besides, weaning-associated feed deprivation in piglets provokes disruptions of MPigut-IVM microbiota composition and functionality and could be implicated in the onset of post-weaning dysbiosis in piglets.

Hepatoprotective Effects of Indole, a Gut Microbial Metabolite, in Leptin-Deficient Obese Mice

BACKGROUND

The gut microbiota plays a role in the occurrence of nonalcoholic fatty liver disease (NAFLD), notably through the production of bioactive metabolites. Indole, a bacterial metabolite of tryptophan, has been proposed as a pivotal metabolite modulating inflammation, metabolism, and behavior.

OBJECTIVES

The aim of our study was to mimic an upregulation of intestinal bacterial indole production and to evaluate its potential effect in vivo in 2 models of NAFLD.

METHODS

Eight-week-old leptin-deficient male ob/ob compared with control ob/+ mice (experiment 1), and 4-5-wk-old C57BL/6JRj male mice fed a low-fat (LF, 10 kJ%) compared with a high-fat (HF, 60 kJ%) diet (experiment 2), were given plain water or water supplemented with a physiological dose of indole (0.5 mM, n ≥6/group) for 3 wk and 3 d, respectively. The effect of the treatments on the liver, intestine, adipose tissue, brain, and behavior was assessed.

RESULTS

Indole reduced hepatic expression of genes involved in inflammation [C-C motif chemokine ligand 2 (Ccl2), C-X-C motif chemokine ligand 2 (Cxcl2); 3.3- compared with 5.0-fold, and 2.4- compared with 3.3-fold of control ob/+ mice, respectively, P < 0.05], and in macrophage activation [Cd68, integrin subunit α X (Itgax); 2.1- compared with 2.5-fold, and 5.0- compared with 6.4-fold of control ob/+ mice, respectively, P < 0.01] as well as markers of hepatic damage (alaninine aminotransferase; -32%, P < 0.001) regardless of genotype in experiment 1. Indole had no effect on hepatic inflammation in mice fed the LF or HF diet in experiment 2. Indole did not change hepatic lipid content, anxiety-like behavior, or inflammation in the ileum, adipose tissue, and brain in experiment 1.

CONCLUSIONS

Our results support the efficacy of indole to reduce hepatic damage and associated inflammatory response and macrophage activation in ob/ob mice. These modifications appear to be attributable to direct effects of indole on the liver, rather than through effects on the adipose tissue or intestinal barrier.

A Collaborative Model to Implement Flexible, Accessible and Efficient Oncogenetic Services for Hereditary Breast and Ovarian Cancer: The C-MOnGene Study

Simple Summary

We recently developed an oncogenetic model to overcome the unprecedented demand for genetic counseling and testing for hereditary breast and ovarian cancer. Quality and performance indicators showed that the implementation of this model improved access to genetic counseling and minimized delays for genetic tests for patients, who reported to be overwhelmingly satisfied with the process. However, it remains unknown whether this model is robust and sustainable or requires adjustments. In addition, whether the model could be deployed elsewhere remains also to be elucidated. The C-MOnGene study was therefore designed to gain an in-depth understanding of the context in which the model was developed and implemented, and document the lessons that can be learned to optimize oncogenetic services delivery in other settings.

Abstract

Medical genetic services are facing an unprecedented demand for counseling and testing for hereditary breast and ovarian cancer (HBOC) in a context of limited resources. To help resolve this issue, a collaborative oncogenetic model was recently developed and implemented at the CHU de Québec-Université Laval; Quebec; Canada. Here, we present the protocol of the C-MOnGene (Collaborative Model in OncoGenetics) study, funded to examine the context in which the model was implemented and document the lessons that can be learned to optimize the delivery of oncogenetic services. Within three years of implementation, the model allowed researchers to double the annual number of patients seen in genetic counseling. The average number of days between genetic counseling and disclosure of test results significantly decreased. Group counseling sessions improved participants’ understanding of breast cancer risk and increased knowledge of breast cancer and genetics and a large majority of them reported to be overwhelmingly satisfied with the process. These quality and performance indicators suggest this oncogenetic model offers a flexible, patient-centered and efficient genetic counseling and testing for HBOC. By identifying the critical facilitating factors and barriers, our study will provide an evidence base for organizations interested in transitioning to an oncogenetic model integrated into oncology care; including teams that are not specialized but are trained in genetics.

Functional Amino Acids in Pigs and Chickens: Implication for Gut Health

In pigs and broiler chickens, the gastrointestinal tract or gut is subjected to many challenges which alter performance, animal health, welfare and livability. Preventive strategies are needed to mitigate the impacts of these challenges on gut health while reducing the need to use antimicrobials. In the first part of the review, we propose a common definition of gut health for pig and chickens relying on four pillars, which correspond to the main functions of the digestive tract: (i) epithelial barrier and digestion, (ii) immune fitness, (iii) microbiota balance and (iv) oxidative stress homeostasis. For each pillar, we describe the most commonly associated indicators. In the second part of the review, we present the potential of functional amino acid supplementation to preserve and improve gut health in piglets and chickens. We highlight that amino acid supplementation strategies, based on their roles as precursors of energy and functional molecules, as signaling molecules and as microbiota modulators can positively contribute to gut health by supporting or restoring its four intertwined pillars. Additional work is still needed in order to determine the effective dose of supplementation and mode of administration that ensure the full benefits of amino acids. For this purpose, synergy between amino acids, effects of amino acid-derived metabolites and differences in the metabolic fate between free and protein-bound amino acids are research topics that need to be furtherly investigated.

Short-chain fatty acids and bile acids in human faeces are associated with the intestinal cholesterol conversion status

BACKGROUND AND PURPOSE

The analysis of human faecal metabolites can provide an insight into metabolic interactions between gut microbiota and the host organism. The creation of metabolic profiles in faeces has received little attention until now, and reference values, especially in the context of dietary and therapeutic interventions, are missing. Exposure to xenobiotics significantly affects the physiology of the microbiome, and microbiota manipulation and short-chain fatty acid administration have been proposed as treatment targets for several diseases. The aim of the present study is to give concomitant concentration ranges of faecal sterol species, bile acids and short-chain fatty acids, based on a large cohort.

EXPERIMENTAL APPROACH

Sterol species, bile acids and short-chain fatty acids in human faeces from 165 study participants were quantified by LC-MS/MS. For standardization, we refer all values to dry weight of faeces. Based on the individual intestinal sterol conversion, we classified participants into low and high converters according to their coprostanol/cholesterol ratio.

KEY RESULTS

Low converters excrete more straight-chain fatty acids and bile acids than high converters; 5th and 95th percentile and median of bile acids and short-chain fatty acids were calculated for both groups.

CONCLUSION AND IMPLICATIONS

We give concentration ranges for 16 faecal metabolites that can serve as reference values. Patient stratification into high or low sterol converter groups is associated with significant differences in faecal metabolites with biological activities. Such stratification should then allow better assessment of faecal metabolites before therapeutic interventions.

LINKED ARTICLES

This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.

[Inspiratory muscle training during pulmonary rehabilitation]

INTRODUCTION

Inspiratory muscle training (IMT) is part of the management of patients with pulmonary diseases during rehabilitation. Since the last recommendations of the Société de pneumologie de langue française, several studies have focused on the role of inspiratory muscle training during pulmonary rehabilitation.

BACKGROUND

IMT, in comparison to standard care or sham-IMT, improves the strength and endurance of the inspiratory muscles, decreases dyspnoea during the activities of daily living, improves walking distance and quality of life. However, the different studies did not show an additional effect of IMT during a pulmonary rehabilitation program compared to a rehabilitation program without IMT, with regard to improvement of exercise capacity and quality of life.

OUTLOOK

One study showed an improvement in dyspnoea of effort, but these results are yet to be confirmed. Finally, it seems appropriate to associate IMT with an exercise-training program before chest or abdominal surgery, even if further studies are necessary.

CONCLUSION

During a pulmonary rehabilitation program, IMT does not provide additional benefits. However, when patients cannot perform a global exercise training, IMT has shown benefit. IMT provides additional benefits in pre-operative programs.

Intestinal organoids in farm animals

In livestock species, the monolayer of epithelial cells covering the digestive mucosa plays an essential role for nutrition and gut barrier function. However, research on farm animal intestinal epithelium has been hampered by the lack of appropriate in vitro models. Over the past decade, methods to culture livestock intestinal organoids have been developed in pig, bovine, rabbit, horse, sheep and chicken. Gut organoids from farm animals are obtained by seeding tissue-derived intestinal epithelial stem cells in a 3-dimensional culture environment reproducing in vitro the stem cell niche. These organoids can be generated rapidly within days and are formed by a monolayer of polarized epithelial cells containing the diverse differentiated epithelial progeny, recapitulating the original structure and function of the native epithelium. The phenotype of intestinal organoids is stable in long-term culture and reflects characteristics of the digestive segment of origin. Farm animal intestinal organoids can be amplified in vitro, cryopreserved and used for multiple experiments, allowing an efficient reduction of the use of live animals for experimentation. Most of the studies using livestock intestinal organoids were used to investigate host-microbe interactions at the epithelial surface, mainly focused on enteric infections with viruses, bacteria or parasites. Numerous other applications of farm animal intestinal organoids include studies on nutrient absorption, genome editing and bioactive compounds screening relevant for agricultural, veterinary and biomedical sciences. Further improvements of the methods used to culture intestinal organoids from farm animals are required to replicate more closely the intestinal tissue complexity, including the presence of non-epithelial cell types and of the gut microbiota. Harmonization of the methods used to culture livestock intestinal organoids will also be required to increase the reproducibility of the results obtained in these models. In this review, we summarize the methods used to generate and cryopreserve intestinal organoids in farm animals, present their phenotypes and discuss current and future applications of this innovative culture system of the digestive epithelium.

Gut Microbiota-Derived Metabolite Signature in Suckling and Weaned Piglets

The gut microbiota plays a key role in intestinal development at the suckling-to-weaning transition. The objective of this study was to analyze the production of metabolites by the gut microbiota in suckling and weaned piglets. We studied piglets raised in two separate maternity farms and weaned at postnatal day 21 in the same farm. The fecal metabolome (¹H nuclear magnetic resonance) and the microbiota composition (16S rRNA gene amplicon sequencing) and its predicted functions (PICRUSt2) were analyzed in the same piglets during the suckling period (postnatal day 13) and 2 days after weaning (postnatal day 23). The relative concentrations of the bacterial metabolites methylamine, dimethylamine, cadaverine, tyramine, putrescine, 5-aminovalerate, succinate, and 3-(4-hydroxyphenylpropionate) were higher during the suckling period than after weaning. In contrast, the relative concentrations of the short-chain fatty acids acetate and propionate were higher after weaning than during the suckling period. The maternity of origin of piglets also influenced the level of some bacterial metabolites (propionate and isobutyrate). The fecal metabolome signatures observed in suckling and weaned piglets were associated with specific microbiota-predicted functionalities, structure, and diversity. Gut microbiota-derived metabolites, which are differentially abundant between suckling and weaned piglets (e.g., short-chain fatty acids and biogenic amines), are known to regulate gut health. Thus, identification of metabolome signatures in suckling and weaned piglets paves the way for the development of health-promoting nutritional strategies, targeting the production of bacterial metabolites in early life.

Design and evaluation of an abbreviated pixelwise dynamic contrast enhancement analysis protocol for early extracellular volume fraction estimation

INTRODUCTION

T1-based method is considered as the gold standard for extracellular volume fraction (ECV) mapping. This technique requires at least a 10 min delay after injection to acquire the post injection T1 map. Quantitative analysis of Dynamic Contrast Enhancement (DCE) images could lead to an earlier estimation of an ECV like parameter (2 min). The purpose of this study was to design a quantitative pixel-wise DCE analysis workflow to assess the feasibility of an early estimation of ECV.

METHODS

Fourteen patients with mitral valve prolapse were included in this study. The MR protocol, performed on a 3 T MR scanner, included MOLLI sequences for T1 maps acquisition and a standard SR-turboFlash sequence for dynamic acquisition. DCE data were acquired for at least 120 s. We implemented a full DCE analysis pipeline with a pre-processing step using an innovative motion correction algorithm (RC-REG algorithm) and a post-processing step using the extended Tofts Model (ECV_ETM). Estimated ECV_ETM maps were compared to standard T1-based ECV maps (ECV_T1) with both a Pearson correlation analysis and a group-wise analysis.

RESULTS

Image and map quality assessment showed systematic improvements using the proposed workflow. Strong correlation was found between ECV_ETM, and ECV_T1 values (r-square = 0.87).

CONCLUSION

A DCE analysis workflow based on RC-REG algorithm and ETM analysis can provide good quality parametric maps. Therefore, it is possible to extract ECV values from a 2 min-long DCE acquisition that are strongly correlated with ECV values from the T1 based method.

Amino Acids in Intestinal Physiology and Health

Dietary protein digestion is an efficient process resulting in the absorption of amino acids by epithelial cells, mainly in the jejunum. Some amino acids are extensively metabolized in enterocytes supporting their high energy demand and/or production of bioactive metabolites such as glutathione or nitric oxide. In contrast, other amino acids are mainly used as building blocks for the intense protein synthesis associated with the rapid epithelium renewal and mucin production. Several amino acids have been shown to support the intestinal barrier function and the intestinal endocrine function. In addition, amino acids are metabolized by the gut microbiota that use them for their own protein synthesis and in catabolic pathways releasing in the intestinal lumen numerous metabolites such as ammonia, hydrogen sulfide, branched-chain amino acids, polyamines, phenolic and indolic compounds. Some of them (e.g. hydrogen sulfide) disrupts epithelial energy metabolism and may participate in mucosal inflammation when present in excess, while others (e.g. indole derivatives) prevent gut barrier dysfunction or regulate enteroendocrine functions. Lastly, some recent data suggest that dietary amino acids might regulate the composition of the gut microbiota, but the relevance for the intestinal health remains to be determined. In summary, amino acid utilization by epithelial cells or by intestinal bacteria appears to play a pivotal regulator role for intestinal homeostasis. Thus, adequate dietary supply of amino acids represents a key determinant of gut health and functions.

Culture of rabbit caecum organoids by reconstituting the intestinal stem cell niche in vitro with pharmacological inhibitors or L-WRN conditioned medium

Intestinal organoids are self-organized 3-dimensional (3D) structures formed by a single layer of polarized epithelial cells. This innovative in vitro model is highly relevant to study physiology of the intestinal epithelium and its role in nutrition and barrier function. However, this model has never been developed in rabbits, while it would have potential applications for biomedical and veterinary research. Here, we cultured rabbit caecum organoids with either pharmacological inhibitors (2Ki medium) or L-WRN cells conditioned medium (L-WRN CM) to reconstitute the intestinal stem cell niche in vitro. Large spherical organoids were obtained with the 2Ki medium and this morphology was associated with a high level of proliferation and stem cells markers gene expression. In contrast, organoids cultured with L-WRN CM had a smaller diameter; a greater cell height and part of them were not spherical. When the L-WRN CM was used at low concentration (5%) for two days, the gene expression of stem cells and proliferation markers were very low, while absorptive and secretory cells markers and antimicrobial peptides were elevated. Epithelial cells within organoids were polarized in 3D cultures with 2Ki medium or L-WRN CM (apical side towards the lumen). We cultured dissociated organoid cells in 2D monolayers, which allowed accessibility to the apical compartment. Under these conditions, actin stress fibers were observed with the 2Ki medium, while perijonctionnal localization of actin was observed with the L-WRN CM suggesting, in 2D cultures as well, a higher differentiation level in the presence of L-WRN CM. In conclusion, rabbit caecum organoids cultured with the 2Ki medium were more proliferative and less differentiated than organoids cultured with L-WRN CM. We propose that organoids cultured with the 2Ki medium could be used to rapidly generate in vitro a large number of rabbit intestinal epithelial stem cells while organoids cultured with the L-WRN CM used at low concentration represent a suitable model to study differentiated rabbit epithelium.

Gut microbiota derived metabolites contribute to intestinal barrier maturation at the suckling-to-weaning transition

In suckling mammals, the onset of solid food ingestion is coincident with the maturation of the gut barrier. This ontogenic process is driven by the colonization of the intestine by the microbiota. However, the mechanisms underlying the microbial regulation of the intestinal development in early life are not fully understood. Here, we studied the co-maturation of the microbiota (composition and metabolic activity) and of the gut barrier at the suckling-to-weaning transition by using a combination of experiments in vivo (suckling rabbit model), ex vivo (Ussing chambers) and in vitro (epithelial cell lines and organoids). The microbiota composition, its metabolic activity, para-cellular epithelial permeability and the gene expression of key components of the gut barrier shifted sharply at the onset of solid food ingestion in vivo, despite milk was still predominant in the diet at that time. We found that cecal content sterile supernatant (i.e. containing a mixture of metabolites) obtained after the onset of solid food ingestion accelerated the formation of the epithelial barrier in Caco-2 cells in vitro and our results suggested that these effects were driven by the bacterial metabolite butyrate. Moreover, the treatment of organoids with cecal content sterile supernatant partially replicated in vitro the effects of solid food ingestion on the epithelial barrier in vivo. Altogether, our results show that the metabolites produced by the microbiota at the onset of solid food ingestion contribute to the maturation of the gut barrier at the suckling-to-weaning transition. Targeting the gut microbiota metabolic activity during this key developmental window might therefore be a promising strategy to promote intestinal homeostasis.

FRI0653-HPR AN OLEUROPEIN-BASED DIETARY SUPPLEMENT IMPROVES JOINT FUNCTIONALITY IN OLDER PEOPLE WITH HIGH KNEE JOINT PAIN

Background:

OLE provides oleuropein the most prevalent phenolic component in olive leaves and has been shown to have potent anti-inflammatory and anti-oxidant effects potentially interesting for joint health (1).

Objectives:

The aim of this study was to investigate the effects of a 6-month intervention with an Olive Leaf Extract (OLE) standardized for oleuropein content on knee functionality and biomarkers of bone/cartilage metabolism and inflammation.

Methods:

The study was a randomized, double-blind, placebo-controlled, multi-centric trial of 124 subjects with mild knee pain or mobility issues. Subjects were randomized equally to receive twice a day one capsule of either maltodextrin (control treatment, CT) or 125-mg OLE (BonoliveTM, an Olive Leaf Extract containing 50 mg of Oleuropein) for 6 months. The co-primary endpoints were Knee injury and Osteoarthritis Outcome Score (KOOS) using a self-administered questionnaire and serum Coll2-1NO2 specific biomarker of cartilage degradation. The secondary endpoints were each of the five sub-scales of the KOOS questionnaire, Knee pain VAS score at rest and at walking, OARSI core set of performance-based tests and serum biomarkers (Coll2-1, MPO, CTX1, osteocalcin, PGE2 and Vplex cytokines assay in serum) and concentration of Oleuropein’s metabolites in urine.

Results:

Primary (global KOOS score, biomarker Coll2-1 NO2) and secondary endpoints (the five subscales of the KOOS score) improved time dependently in both groups. OLE treatment showed significantly elevated urinary oleuropein metabolites (oleuropein aglycone, hydroxytyrosol, homovanillyl alcohol and isomer of homovanillyl alcohol), and was well tolerated without significant differences in number of subjects with adverse events. At 6 months, OLE group showed a higher global KOOS score compared to placebo (treatment difference = 3.73; 95% CI = [-4.08;11.54]; p = 0.34), without significant changes of inflammatory and cartilage remodeling biomarkers. Subgroup analyses demonstrated a large and significant treatment effect of OLE in subjects with high walking pain at baseline (14.4; 95% CI = [1.19;27.63], p=0.03). This was observed at 6 months for the global KOOS score and each different subscale and for pain at walking (-23.07;95% CI = [-41.8;-4.2];p=0.02). These treatment effects at 6 months were significant for KOOS score as well as for the subscales Pain and QoL and the pain at walking.

Conclusion:

OLE was not effective on joint discomfort in people with low to moderate pain at baseline but significantly benefited subjects with high pain at treatment initiation. As oleuropein is well-tolerated, OLE can be used to relieve knee joint pain and enhance mobility in subjects with articular pain the most painful subjects.

References:

[1] Horcajada MN, Sanchez C, Membrez Scalfo F, Drion P, Comblain F, Taralla S, Donneau AF, Offord EA, Henrotin Y. Oleuropein or rutin consumption decreases the spontaneous development of osteoarthritis in the Hartley guinea pig. Osteoarthritis Cartilage. 2015 Jan;23(1):94-102

Disclosure of Interests:

Marie-Noelle Horcajada Employee of: nestlé, Maurice Beaumont Employee of: nestle, Nicolas Sauvageot Employee of: Nestlé, Laure Poquet Employee of: Nestlé, Madleen Saboudjian Employee of: Nestlé, Anne-Christine Hick Employee of: Artialis SA, Berenice Costes Employee of: Artialis SA, Laetitia Garcia Employee of: Artialis, Yves Henrotin Grant/research support from: HEEL, TILMAN

Effect of a proanthocyanidin-rich polyphenol extract from avocado on the production of amino acid-derived bacterial metabolites and the microbiota composition in rats fed a high-protein diet

The consumption of high-protein diets (HPDs) increases the flux of undigested proteins moving to the colon. These proteins are hydrolyzed by bacterial proteases and peptidases, releasing amino acids, which in turn are metabolized by the intestinal microbiota (IM) for protein synthesis and production of various metabolites that can exert positive or deleterious effects, depending on their concentrations, at the colonic or systemic level. On the other hand, proanthocyanidins are polymers of flavan-3-ols which cannot be absorbed at the intestinal level, accumulating in the colon where they are fermented by the IM producing metabolites that appear beneficial for colonocytes and also at the peripheral level. This study evaluated the effect of an avocado peel polyphenol extract (AvPPE) rich in proanthocyanidins on the production of cecal bacterial metabolites and microbiota composition in rats fed a HPD. Compared with the normal-protein (NP) group, HPD did not markedly affect the body weight gain of the animals, but increased the kidney weight. Additionally, the HPD induced a higher cecal concentration of ammonia (NH4+/NH3), hydrogen sulfide (H2S) and branched-chain fatty acids (BCFAs). The supplementation with AvPPE attenuated the production of H2S and increased the production of indole. On the other hand, the HPD affected the composition of the cecal microbiota, increasing the relative abundance of the genera Bacteroides and Lactobacillus, while decreasing Prevotella. The AvPPE counteracted the increase induced by the HPD on the genus Lactobacillus, and increased the relative abundance of [Prevotella]. Our results contribute towards explaining the health-promoting effects of proanthocyanidin-rich dietary foodstuffs including fruits and vegetables.

Protective Effect of an Avocado Peel Polyphenolic Extract Rich in Proanthocyanidins on the Alterations of Colonic Homeostasis Induced by a High-Protein Diet

Avocado peel, a byproduct from the avocado pulp industry, is a promising source of polyphenolic compounds. We evaluated the effect of a proanthocyanidin-rich avocado peel polyphenol extract (AvPPE) on the composition and metabolic activity of human fecal microbiota cultured for 24 h in a bioreactor in the presence of high protein (HP) amounts and the effect of the resulting culture supernatants (CSs) on HT-29Glc^-/+ and Caco-2 cells. AvPPE decreased the HP-induced production of ammonia, H₂S, propionate, and isovalerate and increased that of indole and butyrate. Microbiota composition was marginally affected by HP, whileAvPPE increased the microorganisms/abundance of phylum Actinobacteria, families Coriobacteriaceae and Ruminococcaceae, and genus Faecalibacterium. AvPPE failed to prevent the HP-induced decrease of HT-29Glc^-/+ cell viability and energy efficiency but prevented the HP-induced alterations of barrier function in Caco-2 cells. Additionally, the genotoxic effect of the CSs upon HT-29Glc^-/+ was attenuated by AvPPE. Therefore, AvPPE may be considered as a promising product for improving colonic homeostasis.

Nutritional interest of dietary fiber and prebiotics in obesity: Lessons from the MyNewGut consortium

The aim of EU project MyNewGut is to contribute to future public health-related recommendations supported by new insight in gut microbiome and nutrition-host relationship. In this Opinion Paper, we first revisit the concept of dietary fiber, taking into account their interaction with the gut microbiota. This paper also summarizes the main effects of dietary fibers with prebiotic properties in intervention studies in humans, with a particular emphasis on the effects of arabinoxylans and arabinoxylo-oligosaccharides on metabolic alterations associated with obesity. Based on the existing state of the art and future development, we elaborate the steps required to propose dietary guidelines related to dietary fibers, taking into account their interaction with the gut microbiota.

Cysteine-derived hydrogen sulfide and gut health: a matter of endogenous or bacterial origin

PURPOSE OF REVIEW

Hydrogen sulfide (H2S) is produced in the gut from cysteine by epithelial cells and by the intestinal microbiota. Initially considered as a toxic gas, the pleiotropic effects of H2S are now recognized, especially in the colonic mucosa. The aim of this review is to present new experimental data indicating that cysteine-derived H2S is emerging as a key regulator of gut health.

RECENT FINDINGS

Cysteine degradation by the microbiota emerged as a dominant pathway for H2S production. Among bacteria producing H2S from cysteine, Fusobacterium appears as a pivotal genus associated with digestive diseases. H2S promotes or alleviates mucosal inflammation, mostly according to its high (high micromolar to millimolar) or low (nanomolar to low micromolar) concentration, respectively. H2S maintains the integrity of the mucus layer when derived from endogenous metabolism but is detrimental for this parameter when produced in excess by gut microbes. In inflammatory bowel diseases, an upregulation of H2S production from cysteine by the gut microbiota is observed concomitantly with a downregulation of enzymes implicated in its mucosal detoxification. In colorectal cancer patients, an upregulation of both endogenous and microbial H2S production from cysteine are observed at tumor site that might contribute to disease progression.

SUMMARY

H2S is a double-edge sword for the intestinal epithelium. This is related to the bell-shaped effects of H2S, with protective effect at low concentration but deleterious effects at higher concentrations. As the gut microbiota produces much more H2S from cysteine than endogenous metabolism, we consider that the bacterial or epithelial source of H2S is a major determinant of its effects for intestinal health.

High-protein diets for weight management: Interactions with the intestinal microbiota and consequences for gut health. A position paper by the my new gut study group

BACKGROUND & AIMS

This review examines to what extent high-protein diets (HPD), which may favor body weight loss and improve metabolic outcomes in overweight and obese individuals, may also impact the gut environment, shaping the microbiota and the host-microbe (co)metabolic pathways and products, possibly affecting large intestine mucosa homeostasis.

METHODS

PubMed-referenced publications were analyzed with an emphasis on dietary intervention studies involving human volunteers in order to clarify the beneficial vs. deleterious effects of HPD in terms of both metabolic and gut-related health parameters; taking into account the interactions with the gut microbiota.

RESULTS

HPD generally decrease body weight and improve blood metabolic parameters, but also modify the fecal and urinary contents in various bacterial metabolites and co-metabolites. The effects of HPD on the intestinal microbiota composition appear rather heterogeneous depending on the type of dietary intervention. Recently, HPD consumption was shown to modify the expression of genes playing key roles in homeostatic processes in the rectal mucosa, without evidence of intestinal inflammation. Importantly, the effects of HPD on the gut were dependent on the protein source (i.e. from plant or animal sources), a result which should be considered for further investigations.

CONCLUSION

Although HPD appear to be efficient for weight loss, the effects of HPD on microbiota-derived metabolites and gene expression in the gut raise new questions on the impact of HPD on the large intestine mucosa homeostasis leading the authors to recommend some caution regarding the utilization of HPD, notably in a recurrent and/or long-term ways.

[Follow-up and evaluation of plans developed during pulmonary rehabilitation]

BACKGROUND

Pulmonary rehabilitation inevitably contains two essential components: therapeutic education and exercise training. The principal aim of this study was to evaluate the evolution over a year of the realization of plans determined during a pulmonary rehabilitation program (PRP).

METHODS

At the end of a PRP the patient made plans in accordance with his health condition. A telephone enquiry was undertaken at 3, 7 and 12 months to evaluate the progress of the plans, the motivation to perform them, dyspnoea and quality of life.

RESULTS

The data of 65 patients were analyzed (87 inclusions). Fifty-seven percent of the plans continued for one year. Walking had an adherence rating of 71%. Loss of motivation appeared to be the main cause for stopping (20%). Quality of life remained stable (p=0.39) and an increase in dyspnoea, though statistically significant (p<0.01), was of no clinical relevance.

CONCLUSION

The majority of plans were maintained but without clinical effect on the quality of life or the level of dyspnoea. Decreased motivation was the major limitation to realization or continuation of the plans. New studies will have to be implemented to analyze the factors which lead to this decrease.

The Potential Role of the Dipeptidyl Peptidase-4-Like Activity From the Gut Microbiota on the Host Health

The Dipeptidyl peptidase-4 (DPP-4) activity influences metabolic, behavioral and intestinal disorders through the cleavage of key hormones and peptides. Some studies describe the existence of human DPP-4 homologs in commensal bacteria, for instance in Prevotella or Lactobacillus. However, the role of the gut microbiota as a source of DPP-4-like activity has never been investigated. Through the comparison of the DPP-4 activity in the cecal content of germ-free mice (GFM) and gnotobiotic mice colonized with the gut microbiota of a healthy subject, we bring the proof of concept that a significant DPP-4-like activity occurs in the microbiota. By analyzing the existing literature, we propose that DPP-4-like activity encoded by the intestinal microbiome could constitute a novel mechanism to modulate protein digestion as well as host metabolism and behavior.

The DPP-4 inhibitor vildagliptin impacts the gut microbiota and prevents disruption of intestinal homeostasis induced by a Western diet in mice

AIMS/HYPOTHESIS

Dipeptidyl peptidase 4 (DPP-4) inhibitors are agents designed to increase the half-life of incretins. Although they are administered orally, little is known about their effects on the gut microbiota and functions, despite the fact that some bacteria present in the gut microbiota exhibit DPP-4-like activity. Our objective was to study the impact of the DPP-4 inhibitor vildagliptin on gut functions and the intestinal ecosystem in a murine model of obesity induced by a Western diet (WD).

METHODS

Twenty seven male C57BL/6J mice were randomised to receive a control diet, a WD (45% kJ from fat and 17% kJ from sucrose) or a WD + vildagliptin (0.6 mg/ml in drinking water) for 8 weeks.

RESULTS

Vildagliptin significantly reduced DPP-4 activity in the caecal content and faeces. Vildagliptin impacted on the composition of the gut microbiota and its metabolic activity. It mainly decreased Oscillibacter spp. (a direct effect independent of DPP-4 activity was shown on cultured O. valericigenes), increased Lactobacillus spp. and propionate, and reduced the ligands of Toll-like receptors 2 and 4. Vildagliptin protected against the reductions in crypt depth and ileal expression of antimicrobial peptides induced by the WD. In the liver, the expression of immune cell populations (Cd3g and Cd11c [also known as Itgax]) and cytokines was decreased in the WD + vildagliptin-fed mice compared with the WD-fed group. Ex vivo exposure of precision-cut liver slices to vildagliptin showed that this response was not related to a direct effect of the drug on the liver tissue.

CONCLUSIONS/INTERPRETATION

Our study is the first to consider the DPP-4-like activity of the gut microbiota as a target of DPP-4 inhibition. We propose that vildagliptin exerts beneficial effects at the intestinal level in association with modulation of gut microbiota, with consequences for hepatic immunity. If relevant in humans, this could open new therapeutic uses of DPP-4 inhibition to tackle gut dysfunctions in different pathophysiological contexts.

DATA AVAILABILITY

The sequences used for analysis can be found in the MG-RAST database under the project name MYNEWGUT3.

Towards microbiome-informed dietary recommendations for promoting metabolic and mental health: Opinion papers of the MyNewGut project

The gut microbiota coexists in partnership with the human host through adaptations to environmental and physiological changes that help maintain dynamic homeostatic healthy states. Break-down of this delicate balance under sustained exposure to stressors (e.g. unhealthy diets) can, however, contribute to the onset of disease. Diet is a key modifiable environmental factor that modulates the gut microbiota and its metabolic capacities that, in turn, could impact human physiology. On this basis, the diet and the gut microbiota could act as synergistic forces that provide resilience against disease or that speed the progress from health to disease states. Associations between unhealthy dietary patterns, non-communicable diseases and intestinal dysbiosis can be explained by this hypothesis. Translational studies showing that dietary-induced alterations in microbial communities recapitulate some of the pathological features of the original host further support this notion. In this introductory paper by the European project MyNewGut, we briefly summarize the investigations conducted to better understand the role of dietary patterns and food components in metabolic and mental health and the specificities of the microbiome-mediating mechanisms. We also discuss how advances in the understanding of the microbiome's role in dietary health effects can help to provide acceptable scientific grounds on which to base dietary advice for promoting healthy living.

The gut microbiota metabolite indole alleviates liver inflammation in mice

The gut microbiota regulates key hepatic functions, notably through the production of bacterial metabolites that are transported via the portal circulation. We evaluated the effects of metabolites produced by the gut microbiota from aromatic amino acids (phenylacetate, benzoate, p-cresol, and indole) on liver inflammation induced by bacterial endotoxin. Precision-cut liver slices prepared from control mice, Kupffer cell (KC)-depleted mice, and obese mice ( ob/ ob) were treated with or without LPS and bacterial metabolites. We observed beneficial effects of indole that dose-dependently reduced the LPS-induced up-regulation of proinflammatory mediators at both mRNA and protein levels in precision-cut liver slices prepared from control or ob/ ob mice. KC depletion partly prevented the antiinflammatory effects of indole, notably through a reduction of nucleotide-binding domain and leucine-rich repeat containing (NLR) family pyrin domain-containing 3 (NLRP3) pathway activation. In vivo, the oral administration of indole before an LPS injection reduced the expression of key proteins of the NF-κB pathway and downstream proinflammatory gene up-regulation. Indole also prevented LPS-induced alterations of cholesterol metabolism through a transcriptional regulation associated with increased 4β-hydroxycholesterol hepatic levels. In summary, indole appears as a bacterial metabolite produced from tryptophan that is able to counteract the detrimental effects of LPS in the liver. Indole could be a new target to develop innovative strategies to decrease hepatic inflammation.-Beaumont, M., Neyrinck, A. M., Olivares, M., Rodriguez, J., de Rocca Serra, A., Roumain, M., Bindels, L. B., Cani, P. D., Evenepoel, P., Muccioli, G. G., Demoulin, J.-B., Delzenne, N. M. The gut microbiota metabolite indole alleviates liver inflammation in mice.

Quantity and source of dietary protein influence metabolite production by gut microbiota and rectal mucosa gene expression: a randomized, parallel, double-blind trial in overweight humans

Background: Although high-protein diets (HPDs) are frequently consumed for body-weight control, little is known about the consequences for gut microbiota composition and metabolic activity and for large intestine mucosal homeostasis. Moreover, the effects of HPDs according to the source of protein need to be considered in this context.Objective: The objective of this study was to evaluate the effects of the quantity and source of dietary protein on microbiota composition, bacterial metabolite production, and consequences for the large intestinal mucosa in humans.Design: A randomized, double-blind, parallel-design trial was conducted in 38 overweight individuals who received a 3-wk isocaloric supplementation with casein, soy protein, or maltodextrin as a control. Fecal and rectal biopsy-associated microbiota composition was analyzed by 16S ribosomal DNA sequencing. Fecal, urinary, and plasma metabolomes were assessed by ¹H-nuclear magnetic resonance. Mucosal transcriptome in rectal biopsies was determined with the use of microarrays.Results: HPDs did not alter the microbiota composition, but induced a shift in bacterial metabolism toward amino acid degradation with different metabolite profiles according to the protein source. Correlation analysis identified new potential bacterial taxa involved in amino acid degradation. Fecal water cytotoxicity was not modified by HPDs, but was associated with a specific microbiota and bacterial metabolite profile. Casein and soy protein HPDs did not induce inflammation, but differentially modified the expression of genes playing key roles in homeostatic processes in rectal mucosa, such as cell cycle or cell death.Conclusions: This human intervention study shows that the quantity and source of dietary proteins act as regulators of gut microbiota metabolite production and host gene expression in the rectal mucosa, raising new questions on the impact of HPDs on the large intestine mucosa homeostasis. This trial was registered at clinicaltrials.gov as NCT02351297.