Publications by authors named "El-Omar E"

Background/objectives: Growing evidence suggests that the gut-brain axis influences brain function, particularly the role of intestinal microbiota in modulating cognitive processes. Probiotics may alter brain function and behavior by modulating gut microbiota, with implications for neurodegenerative diseases like Alzheimer's disease (AD). The purpose of this review is to systematically review the current literature exploring the effects of probiotic supplementation on gut microbiota and cognitive function in AD and mild cognitive impairment (MCI).

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Up to 50-70% of patients with liver cirrhosis develop hepatic encephalopathy (HE), which is closely related to gut microbiota dysbiosis, with an unclear mechanism. Here, by constructing gut-brain modules to assess bacterial neurotoxins from metagenomic datasets, we found that phenylalanine decarboxylase (PDC) genes, mainly from Ruminococcus gnavus, increased approximately tenfold in patients with cirrhosis and higher in patients with HE. Cirrhotic, not healthy, mice colonized with R.

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There is growing interest in the potential exploitation of the gut microbiome as a diagnostic tool in medicine, but evidence supporting its clinical usefulness is scarce. An increasing number of commercial providers offer direct-to-consumer microbiome diagnostic tests without any consensus on their regulation or any proven value in clinical practice, which could result in considerable waste of individual and health-care resources and potential drawbacks in the clinical management of patients. We convened an international multidisciplinary expert panel to standardise best practices of microbiome testing for clinical implementation, including recommendations on general principles and minimum requirements for their provision, indications, pre-testing protocols, method of analyses, reporting of results, and potential clinical value.

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Endometriosis is a chronic, inflammatory, oestrogen-dependent disorder that is defined by the presence of endometrium-like tissue in the extra-uterine environment. It is estimated to affect approximately 10% of women of reproductive age, and the cause is still largely unknown. The heterogenous nature and complex pathophysiology of the disease results in diagnostic and therapeutic challenges.

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  • A pilot study aimed to identify a microbial signature for endometriosis as a non-invasive diagnostic tool was conducted in Australia, involving 64 participants divided into three groups: healthy controls, non-endometriosis patients, and those with confirmed endometriosis.
  • Self-collected samples from the oral cavity, stool, and vagina were analyzed using advanced sequencing techniques to uncover differences in microbial composition among the groups, with significant findings from both oral and stool microbiota.
  • Results revealed distinct microbiota profiles, particularly highlighting that Fusobacterium was more abundant in the oral samples of patients with moderate to severe endometriosis, suggesting the potential of using microbiome analysis for diagnosis and treatment strategies in endometriosis.
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  • - The global prevalence of Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is increasing, but effective treatments are still scarce.
  • - Research is focusing on the connection between the gut microbiome and MASLD, with the potential for gut-targeted therapies to help manage or prevent the disease.
  • - This review will explore how the gut microbiome's structure and function relate to MASLD, evaluate gut microbiome signatures for diagnosing disease severity, and look into both current and potential therapies targeting the interactions between the gut microbiome and liver.
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The genetic contribution to inflammatory bowel disease (IBD) encompassing both Crohn's disease (CD) and ulcerative colitis (UC), accounts for around 20% of disease variance, highlighting the need to characterise environmental and epigenetic influences. Recently considerable progress has been made in characterising the adult methylome, in epigenome-wide association studies. We report detailed analysis of the circulating methylome in 86 patients with childhood-onset CD,UC and 30 controls using the Illumina Infinium Human MethylationEPIC platform.

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  • The text discusses how changes in the microbiome can impact chronic diseases and therapies, leading to the development of microbiota-centered treatments like probiotics and faecal microbiota transplantation.
  • It highlights the confusion surrounding the term 'dysbiosis' and the challenge of defining what a 'healthy microbiome' is, questioning which group of individuals truly represents health.
  • The review emphasizes the need for a more nuanced understanding of gut health, considering various individual, dietary, and environmental factors, as well as the complexities in measuring gut function.
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Objective: During the last decade, the management of gastric intestinal metaplasia (GIM) has been addressed by several distinct international evidence-based guidelines. In this review, we aimed to synthesise these guidelines and provide clinicians with a global perspective of the current recommendations for managing patients with GIM, as well as highlight evidence gaps that need to be addressed with future research.

Design: We conducted a systematic review of the literature for guidelines and consensus statements published between January 2010 and February 2023 that address the diagnosis and management of GIM.

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  • Chemotherapy can lead to premature ovarian insufficiency (CIPOI) in women, causing loss of fertility and no effective treatments currently exist.
  • Fecal microbiota transplantation studies in mice show that an unhealthy gut microbiome contributes to ovarian problems in CIPOI, particularly due to a decrease in certain beneficial bacteria (Limosilactobacillus reuteri) and its byproducts.
  • Supplementing with L. reuteri or its compound β-resorcylic acid (β-RA) helps protect ovarian health, maintains hormone balance, and prevents apoptosis of key ovarian cells, suggesting new avenues for preserving fertility during cancer treatment.
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Cocaine use disorder (CUD) is a global health problem with no approved medications. One potential treatment target is the gut microbiome, but it is unknown if cocaine induces long-lasting effects on gut microbes. A novel therapeutic candidate for CUD, cannabidiol (CBD), can improve gut function in rodent models.

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Introduction: Vaginal estrogen is a treatment for genitourinary symptoms of menopause (GSM), which comprises vaginal atrophy and urinary dysfunction, including incontinence. Previous studies show that estrogen therapy promotes lactobacilli abundance and is associated with reduced GSM symptoms, including reduction of stress incontinence. However, detailed longitudinal studies that characterize how the microbiome changes in response to estrogen are scarce.

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At the end of the last century, a far-sighted 'working party' held in Sydney, Australia addressed the clinicopathological issues related to gastric inflammatory diseases. A few years later, an international conference held in Houston, Texas, USA critically updated the seminal Sydney classification. In line with these initiatives, Kyoto Global Consensus Report, flanked by the Maastricht-Florence conferences, added new clinical evidence to the gastritis clinicopathological puzzle.

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  • The study evaluated the global prevalence of Helicobacter pylori (H pylori) infection in adults and children/adolescents, linking it to gastric cancer rates.
  • After reviewing nearly 17,000 articles, researchers found that H pylori infection prevalence dropped from 52.6% to 43.9% in adults but remained at 35.1% in children and adolescents from 2015 to 2022.
  • The decline in H pylori in adults was significant in certain regions, while the relationship between H pylori prevalence and decreasing gastric cancer incidence prompts the need for further large-scale clinical trials to confirm these findings.
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Cholangiocarcinoma (CCA) is a serious health problem worldwide. The gut and bile microbiota have not been clearly characterized in patients with CCA, and better noninvasive diagnostic approaches for CCA need to be established. The aim of this study was to investigate the characteristics of the gut and bile microbiota in CCA patients.

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Background: We previously showed rising primary antibiotic resistance of Helicobacter pylori during 1990-2015 in the Asia-Pacific region. However, whether primary antibiotic resistance continues to rise is unknown. Therefore, we aimed to assess the latest prevalence of H pylori antibiotic resistance in this region.

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  • The study investigates the connection between the microbiome and adverse perinatal health outcomes, aiming to understand how dysbiosis affects pregnancy and postpartum health.
  • To achieve this, 2000 Australian women will be recruited and monitored over a span of 7 years, with samples collected regularly before, during, and after pregnancy.
  • Data will include multiple biological samples and assessments on health, lifestyle, and environmental factors, allowing for comprehensive analysis of the microbiome's influence on maternal and child health.
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Background: The results of human observational studies on the correlation between gut microbiota perturbations and polycystic ovary syndrome (PCOS) have been contradictory. This study aimed to perform the first systematic review and meta-analysis to evaluate the specificity of the gut microbiota in PCOS patients compared to healthy women.

Methods: Literature through May 22, 2023, was searched on PubMed, Web of Science, Medline, Embase, Cochrane Library, and Wiley Online Library databases.

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Background: Helicobacter pylori infection is an important causal factor of gastric cancer and peptic ulcer disease and is associated with immune thrombocytopenic purpura and functional dyspepsia. In H pylori strains, point mutations in the 23S rRNA and gyrA genes are associated with clarithromycin resistance and levofloxacin resistance, respectively. Whether the efficacy of molecular testing-guided therapy is non-inferior to that of susceptibility testing-guided therapy for H pylori eradication is unclear.

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Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated.

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Dietary intake during pregnancy may influence the antenatal microbiome, which is proposed to impact maternal and infant health during the pregnancy and beyond. The aim of this sub-study was to examine associations between dietary intake and microbiota diversity during pregnancy using whole metagenomic sequencing and examine associations in low-risk versus high-risk pregnancies, as well as complicated versus uncomplicated pregnancies. Pregnancy data were analysed from women participating in the MUMS cohort study in Sydney, Australia (women followed from trimester 1 of pregnancy to 1-year postpartum), who had dietary intake data at either trimester 1 or 3, assessed using the Australian Eating Survey, and a matched stool sample ( = 86).

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