Elucidating the dynamics and impact of the gut microbiome on maternal nutritional status during pregnancy, effect on pregnancy outcomes and infant health in rural Pakistan: study protocol for a prospective, longitudinal observational study

Introduction
Undernutrition during pregnancy is linked to adverse pregnancy and birth outcomes and has downstream effects on the growth and development of children. The gut microbiome has a profound influence on the nutritional status of the host. This phenomenon is understudied in settings with a high prevalence of undernutrition, and further investigation is warranted to better understand such interactions.

Methods and analysis
This is a prospective, longitudinal observational study to investigate the relationship between prokaryotic and eukaryotic microbes in the gut and their association with maternal body mass index (BMI), gestational weight gain, and birth and infant outcomes among young mothers (17–24 years) in Matiari District, Pakistan. We aim to enrol 400 pregnant women with low and normal BMIs at the time of recruitment (

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Agosto 2024

Lactococcus lactis HkyuLL 10 suppresses colorectal tumourigenesis and restores gut microbiota through its generated alpha-mannosidase

Objective
Probiotic Lactococcus lactis is known to confer health benefits to humans. Here, we aimed to investigate the role of L. lactis in colorectal cancer (CRC).

Design
L. lactis abundance was evaluated in patients with CRC (n=489) and healthy individuals (n=536). L. lactis was isolated from healthy human stools with verification by whole genome sequencing. The effect of L. lactis on CRC tumourigenesis was assessed in transgenic Apc Min/+ mice and carcinogen-induced CRC mice. Faecal microbiota was profiled by metagenomic sequencing. Candidate proteins were characterised by nano liquid chromatography-mass spectrometry. Biological function of L. lactis conditioned medium (HkyuLL 10-CM) and functional protein was studied in human CRC cells, patient-derived organoids and xenograft mice.

Results
Faecal L. lactis was depleted in patients with CRC. A new L. lactis strain was isolated from human stools and nomenclated as HkyuLL 10. HkyuLL 10 supplementation suppressed CRC tumourigenesis in Apc Min/+ mice, and this tumour-suppressing effect was confirmed in mice with carcinogen-induced CRC. Microbiota profiling revealed probiotic enrichment including Lactobacillus johnsonii in HkyuLL 10-treated mice. HkyuLL 10-CM significantly abrogated the growth of human CRC cells and patient-derived organoids. Such protective effect was attributed to HkyuLL 10-secreted proteins, and we identified that α-mannosidase was the functional protein. The antitumourigenic effect of α-mannosidase was demonstrated in human CRC cells and organoids, and its supplementation significantly reduced tumour growth in xenograft mice.

Conclusion
HkyuLL 10 suppresses CRC tumourigenesis in mice through restoring gut microbiota and secreting functional protein α-mannosidase. HkyuLL 10 administration may serve as a prophylactic measure against CRC.

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Agosto 2024

Helicobacter pylori infection alters gut virome by expanding temperate phages linked to increased risk of colorectal cancer

Colorectal cancer (CRC) has low survival rates and can be influenced by various factors, including genetics, lifestyle and an altered microbiome.1 Recent studies indicate that Helicobacter pylori infection may also play a role in CRC development.2 This is of significant concern as over half of the world’s population carries H. pylori, which can cause gastric inflammation and potentially lead to cancer.3 In a recent study,4 we demonstrated that H. pylori infection in Apc-mutant mice could accelerate tumour development by causing immune and epithelial changes that are linked to tumorigenesis. We observed similar changes in H. pylori-infected patients.4 In addition, we found that treating the infection with antibiotics such as clarithromycin, metronidazole and omeprazole, at an early stage of infection can eradicate H. pylori4 and reduce the tumour occurrence to a normal level.4 These findings revealed…

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Agosto 2024

Landscape of the gut mycobiome dynamics during pregnancy and its relationship with host metabolism and pregnancy health

Objective
The remodelling of gut mycobiome (ie, fungi) during pregnancy and its potential influence on host metabolism and pregnancy health remains largely unexplored. Here, we aim to examine the characteristics of gut fungi in pregnant women, and reveal the associations between gut mycobiome, host metabolome and pregnancy health.

Design
Based on a prospective birth cohort in central China (2017 to 2020): Tongji-Huaxi-Shuangliu Birth Cohort, we included 4800 participants who had available ITS2 sequencing data, dietary information and clinical records during their pregnancy. Additionally, we established a subcohort of 1059 participants, which included 514 women who gave birth to preterm, low birthweight or macrosomia infants, as well as 545 randomly selected controls. In this subcohort, a total of 750, 748 and 709 participants had ITS2 sequencing data, 16S sequencing data and serum metabolome data available, respectively, across all trimesters.

Results
The composition of gut fungi changes dramatically from early to late pregnancy, exhibiting a greater degree of variability and individuality compared with changes observed in gut bacteria. The multiomics data provide a landscape of the networks among gut mycobiome, biological functionality, serum metabolites and pregnancy health, pinpointing the link between Mucor and adverse pregnancy outcomes. The prepregnancy overweight status is a key factor influencing both gut mycobiome compositional alteration and the pattern of metabolic remodelling during pregnancy.

Conclusion
This study provides a landscape of gut mycobiome dynamics during pregnancy and its relationship with host metabolism and pregnancy health, which lays the foundation of the future gut mycobiome investigation for healthy pregnancy.

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Luglio 2024

Exploring the impact of gut microbial metabolites on inactivated SARS-CoV-2 vaccine efficacy during pregnancy and mother-to-infant antibody transfer

The recent publication by Ng et al titled ‘Gut microbiota composition is associated with SARS-CoV-2 vaccine immunogenicity and adverse events’ provides valuable insights on gut microbiota in modulating immune responses to both inactivated (CoronaVac) and mRNA (BNT162b2) SARS-CoV-2 vaccines. The authors identified specific gut microbiota markers influenced immunity and vaccine efficacy, suggesting that microbiota-targeted interventions could potentially enhance vaccine effectiveness in adults.1 Expanding on Ng et al’s research, our study further investigates the associations between gut microbial taxa, metabolites and immune response to inactivated vaccines. Our findings establish a connection between maternal gut microbiota/metabolites and the efficacy of mother-to-infant antibody transfer, providing a potential protective strategy for infants against COVID-19 symptoms. We conducted a prospective, observational investigation involving 97 vaccinated pregnant women in Guangdong, China, and profiled gut microbiota and metabolome using shotgun metagenomics and non-targeted metabolomics. All participants received two doses of inactivated SARS-CoV-2 vaccine, including…

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Luglio 2024

Gut Pathobiont-Derived Outer Membrane Vesicles Drive Liver Inflammation and Fibrosis in PSC-IBD

Primary sclerosing cholangitis (PSC), often associated with inflammatory bowel disease (IBD), presents a multifactorial etiology involving genetic, immunological, and environmental factors. Gut dysbiosis and bacterial translocation have been implicated in PSC-IBD, yet the precise mechanisms underlying their pathogenesis remain elusive. Here, we describe the role of gut pathobionts in promoting liver inflammation and fibrosis due to the release of bacterial outer membrane vesicles (OMVs).

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Luglio 2024

Effects of almond consumption compared with the consumption of traditional isocaloric cereal/pulse-based snacks on glycaemic control and gut health in adults with pre-diabetes in rural India: protocol for a 16-week, parallel-arm, cluster randomised controlled trial

Introduction
Almonds have prebiotic potential to maintain gut health and regulate glycaemia. Western studies have shown their positive effects on preventing non-communicable diseases like diabetes and cardiovascular diseases. However, there is a lack of research involving Asian Indians, who have a higher predisposition to diabetes due to their unique ‘Asian phenotype’. Therefore, this study aims to evaluate the impact of almond supplementation on glycaemic control and gut health in adults with pre-diabetes in rural India through a randomised clinical trial.

Methods and analysis
A parallel cluster randomised controlled trial with 178 participants with pre-diabetes (assigned 1:1) aged 20–50 years, of both genders, with a body mass index of 18.9–25 kg/m2, will be conducted in rural areas of Chikkaballapur, Kolar and Rural Bangalore districts in India. The intervention group will receive 56 g of almonds as mid-morning snacks for 16 weeks, while the control group will receive cereal/pulse-based traditional isocaloric snacks under the closed supervision of the study investigators. The primary outcome of the study is HbA1c measured at the 16th week. The secondary outcomes—anthropometry, clinical and other biochemical parameters—will be measured at 0th, 8th and 16th weeks, and a subgroup of 120 participants will undergo gut health analysis. Glucagon-like peptide 1 analysis will be conducted on 30 participants at 0th and 16th weeks. Statistical analysis will be performed using SPSS for Windows V.27.0, and both intention-to-treat and per-protocol analyses will be conducted.

Ethics and dissemination
Ethics approval was obtained from the Institutional Ethics Committee at Ramaiah Medical College, Bangalore, Karnataka, India (DRPEFP7672021). We will obtain the informed written consent of the participants prior to screening and enrolling them in the study. Results from this trial will be disseminated through publication in peer-reviewed journals and scientific gatherings.

Trial registration number
Clinical Trial Registry of India (CTRI/2023/03/050421).

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Luglio 2024

Dietary Acculturation Is Associated With Altered Gut Microbiome, Circulating Metabolites, and Cardiovascular Disease Risk in US Hispanics and Latinos: Results From HCHS/SOL

Circulation, Ahead of Print. BACKGROUND:Dietary acculturation, or adoption of dominant culture diet by migrant groups, influences human health. We aimed to examine dietary acculturation and its relationships with cardiovascular disease (CVD), gut microbiota, and blood metabolites among US Hispanic and Latino adults.METHODS:In the HCHS/SOL (Hispanic Community Health Study/Study of Latinos), US exposure was defined by years in the United States (50 states and Washington, DC) and US nativity. A dietary acculturation pattern was derived from 14 172 participants with two 24-hour dietary recalls at baseline (2008–2011) using least absolute shrinkage and selection operator regression, with food groups as predictors of US exposure. We evaluated associations of dietary acculturation with incident CVD across ≈7 years of follow-up (n=211/14 172 cases/total) and gut microbiota (n=2349; visit 2, 2014 to 2017). Serum metabolites associated with both dietary acculturation–related gut microbiota (n=694) and incident CVD (n=108/5256 cases/total) were used as proxy measures to assess the association of diet-related gut microbiome with incident CVD.RESULTS:We identified an empirical US-oriented dietary acculturation score that increased with US exposure. Higher dietary acculturation score was associated with higher risk of incident CVD (hazard ratio per SD, 1.33 [95% CI, 1.13–1.57]), adjusted for sociodemographic, lifestyle, and clinical factors. Sixty-nine microbial species (17 enriched from diverse species, 52 depleted mainly from fiber-utilizingClostridiaandPrevotellaspecies) were associated with dietary acculturation, driven by lower intakes of whole grains, beans, and fruits and higher intakes of refined grains. Twenty-five metabolites, involved predominantly in fatty acid and glycerophospholipid metabolism (eg, branched-chain 14:0 dicarboxylic acid** and glycerophosphoethanolamine), were associated with both diet acculturation-related gut microbiota and incident CVD. Proxy association analysis based on these metabolites suggested a positive relationship between diet acculturation-related microbiome and risk of CVD (r=0.70,P

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Giugno 2024

Clinical, experimental and pathophysiological effects of Yaq-001: a non-absorbable, gut-restricted adsorbent in models and patients with cirrhosis

Objective
Targeting bacterial translocation in cirrhosis is limited to antibiotics with risk of antimicrobial resistance. This study explored the therapeutic potential of a non-absorbable, gut-restricted, engineered carbon bead adsorbent, Yaq-001 in models of cirrhosis and acute-on-chronic liver failure (ACLF) and, its safety and tolerability in a clinical trial in cirrhosis.

Design
Performance of Yaq-001 was evaluated in vitro. Two-rat models of cirrhosis and ACLF, (4 weeks, bile duct ligation with or without lipopolysaccharide), receiving Yaq-001 for 2 weeks; and two-mouse models of cirrhosis (6-week and 12-week carbon tetrachloride (CCl4)) receiving Yaq-001 for 6 weeks were studied. Organ and immune function, gut permeability, transcriptomics, microbiome composition and metabolomics were analysed. The effect of faecal water on gut permeability from animal models was evaluated on intestinal organoids. A multicentre, double-blind, randomised, placebo-controlled clinical trial in 28 patients with cirrhosis, administered 4 gr/day Yaq-001 for 3 months was performed.

Results
Yaq-001 exhibited rapid adsorption kinetics for endotoxin. In vivo, Yaq-001 reduced liver injury, progression of fibrosis, portal hypertension, renal dysfunction and mortality of ACLF animals significantly. Significant impact on severity of endotoxaemia, hyperammonaemia, liver cell death, systemic inflammation and organ transcriptomics with variable modulation of inflammation, cell death and senescence in the liver, kidneys, brain and colon was observed. Yaq-001 reduced gut permeability in the organoids and impacted positively on the microbiome composition and metabolism. Yaq-001 regulated as a device met its primary endpoint of safety and tolerability in the clinical trial.

Conclusions
This study provides strong preclinical rationale and safety in patients with cirrhosis to allow clinical translation.

Trial registration number
NCT03202498.

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Giugno 2024

Postprandial symptoms in disorders of gut-brain interaction and their potential as a treatment target

Postprandial, or meal-related, symptoms, such as abdominal pain, early satiation, fullness or bloating, are often reported by patients with disorders of gut-brain interaction, including functional dyspepsia (FD) or irritable bowel syndrome (IBS). We propose that postprandial symptoms arise via a distinct pathophysiological process. A physiological or psychological insult, for example, acute enteric infection, leads to loss of tolerance to a previously tolerated oral food antigen. This enables interaction of both the microbiota and the food antigen itself with the immune system, causing a localised immunological response, with activation of eosinophils and mast cells, and release of inflammatory mediators, including histamine and cytokines. These have more widespread systemic effects, including triggering nociceptive nerves and altering mood. Dietary interventions, including a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols, elimination of potential food antigens or gluten, IgG food sensitivity diets or salicylate restriction may benefit some patients with IBS or FD. This could be because the restriction of these foods or dietary components modulates this pathophysiological process. Similarly, drugs including proton pump inhibitors, histamine-receptor antagonists, mast cell stabilisers or even tricyclic or tetracyclic antidepressants, which have anti-histaminergic actions, all of which are potential treatments for FD and IBS, act on one or more of these mechanisms. It seems unlikely that food antigens driving intestinal immune activation are the entire explanation for postprandial symptoms in FD and IBS. In others, fermentation of intestinal carbohydrates, with gas release altering reflex responses, adverse reactions to food chemicals, central mechanisms or nocebo effects may dominate. However, if the concept that postprandial symptoms arise from food antigens driving an immune response in the gastrointestinal tract in a subset of patients is correct, it is paradigm-shifting, because if the choice of treatment were based on one or more of these therapeutic targets, patient outcomes may be improved.

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Giugno 2024

Clarithromycin-containing triple therapy for Helicobacter pylori eradication is inducing increased long-term resistant bacteria communities in the gut

The current European guidelines (Maastricht VI/Florence consensus report) on the management of Helicobacter pylori infection1 recommend population-based H. pylori screening programmes for asymptomatic individuals in the general population to eradicate the microorganism for gastric cancer prevention. However, this is expected to result in a considerable increase in antibiotic use2 as half of the global population are estimated to be infected.3 Therefore, the guidelines suggest that caution is required in choosing the appropriate antibiotics to minimise antimicrobial resistance.1 The importance of gut resistome induction following H. pylori eradication therapies has been debated for years, and the available information is controversial; the general thought is that normal gut microbiota is restored 3–6 months after antibiotic treatment.4 Therefore, we conducted a randomised controlled clinical trial as part of the GISTAR study5 in Latvia by evaluating alterations in gut microbiota before…

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Giugno 2024

Compared to histamine-2 receptor antagonist, proton pump inhibitor induces stronger oral-to-gut microbial transmission and gut microbiome alterations: a randomised controlled trial

Objective
We aim to compare the effects of proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs) on the gut microbiota through longitudinal analysis.

Design
Healthy volunteers were randomly assigned to receive either PPI (n=23) or H2RA (n=26) daily for seven consecutive days. We collected oral (saliva) and faecal samples before and after the intervention for metagenomic next-generation sequencing. We analysed intervention-induced alterations in the oral and gut microbiome including microbial abundance and growth rates, oral-to-gut transmissions, and compared differences between the PPI and H2RA groups.

Results
Both interventions disrupted the gut microbiota, with PPIs demonstrating more pronounced effects. PPI usage led to a significantly higher extent of oral-to-gut transmission and promoted the growth of specific oral microbes in the gut. This led to a significant increase in both the number and total abundance of oral species present in the gut, including the identification of known disease-associated species like Fusobacterium nucleatum and Streptococcus anginosus. Overall, gut microbiome-based machine learning classifiers could accurately distinguish PPI from non-PPI users, achieving an area under the receiver operating characteristic curve (AUROC) of 0.924, in contrast to an AUROC of 0.509 for H2RA versus non-H2RA users.

Conclusion
Our study provides evidence that PPIs have a greater impact on the gut microbiome and oral-to-gut transmission than H2RAs, shedding light on the mechanism underlying the higher risk of certain diseases associated with prolonged PPI use.

Trial registration number
ChiCTR2300072310.

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Giugno 2024