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Fulltext When dysbiosis meets dystrophy: an unwanted gut-muscle connection

Jayaraman A, Pettersson S

EMBO Mol Med, 2023 Mar 08;15(3):e17324.
PMID: 36843560 DOI: 10.15252/emmm.202217324

Duchenne muscular dystrophy (DMD) is a devastating neuromuscular degenerative disease with no known cure to date. In recent years, the hypothesis of a "gut-muscle axis" has emerged suggesting that bidirectional communication between the gut microbiota and the muscular system regulates the muscular function and may be perturbed in several muscular disorders. In addition, the excessive consumption of sugar and of lipid-rich processed food products are factors that further aggravate the phenotype for such diseases and accelerate biological aging. However, these unhealthy microbiota profiles can be reversed by individualized dietary changes to not only alter the microbiota composition but also to reset the production of microbial metabolites known to trigger beneficial effects typically associated with prolonged health span. Two recent studies (in this issue of EMBO Mol Med) highlight the interesting potential of microbiota-informed next-generation dietary intervention programs to be considered in genetically linked muscle disorders like DMD.

Matched MeSH terms: Dysbiosis*
Fulltext The Blood Microbiome and Health: Current Evidence, Controversies, and Challenges

Cheng HS, Tan SP, Wong DMK, Koo WLY, Wong SH, Tan NS

Int J Mol Sci, 2023 Mar 15;24(6).
PMID: 36982702 DOI: 10.3390/ijms24065633

Blood is conventionally thought to be sterile. However, emerging evidence on the blood microbiome has started to challenge this notion. Recent reports have revealed the presence of genetic materials of microbes or pathogens in the blood circulation, leading to the conceptualization of a blood microbiome that is vital for physical wellbeing. Dysbiosis of the blood microbial profile has been implicated in a wide range of health conditions. Our review aims to consolidate recent findings about the blood microbiome in human health and to highlight the existing controversies, prospects, and challenges around this topic. Current evidence does not seem to support the presence of a core healthy blood microbiome. Common microbial taxa have been identified in some diseases, for instance, Legionella and Devosia in kidney impairment, Bacteroides in cirrhosis, Escherichia/Shigella and Staphylococcus in inflammatory diseases, and Janthinobacterium in mood disorders. While the presence of culturable blood microbes remains debatable, their genetic materials in the blood could potentially be exploited to improve precision medicine for cancers, pregnancy-related complications, and asthma by augmenting patient stratification. Key controversies in blood microbiome research are the susceptibility of low-biomass samples to exogenous contamination and undetermined microbial viability from NGS-based microbial profiling, however, ongoing initiatives are attempting to mitigate these issues. We also envisage future blood microbiome research to adopt more robust and standardized approaches, to delve into the origins of these multibiome genetic materials and to focus on host-microbe interactions through the elaboration of causative and mechanistic relationships with the aid of more accurate and powerful analytical tools.

Matched MeSH terms: Dysbiosis/microbiology
Fulltext Manipulating the Gut Microbiome as a Therapeutic Strategy to Mitigate Late Effects in Childhood Cancer Survivors

Oh L, Ab Rahman S, Dubinsky K, Azanan MS, Ariffin H

Technol Cancer Res Treat, 2023;22:15330338221149799.
PMID: 36624625 DOI: 10.1177/15330338221149799

Recent studies have identified causal links between altered gut microbiome, chronic inflammation, and inflammation-driven conditions such as diabetes and cardiovascular disease. Childhood cancer survivors (CCS) show late effects of therapy in the form of inflammaging-related disorders as well as microbial dysbiosis, supporting a hypothesis that the conditions are interconnected. Given the susceptibility of the gut microbiome to alteration, a number of therapeutic interventions have been investigated for the treatment of inflammatory conditions, though not within the context of cancer survivorship in children and adolescents. Here, we evaluate the potential for these interventions, which include probiotic supplementation, prebiotics/fiber-rich diet, exercise, and fecal microbiota transplantation for prevention and treatment of cancer treatment-related microbial dysbiosis in survivors. We also make recommendations to improve adherence and encourage long-term lifestyle changes for maintenance of healthy gut microbiome in CCS as a potential strategy to mitigate treatment-related late effects.

Matched MeSH terms: Dysbiosis/etiology; Dysbiosis/therapy
The Role of the Gut Microbiome in Hematological Cancers

Hussein N, Rajasuriar R, Khan AM, Lim YA, Gan GG

Mol Cancer Res, 2024 Jan 02;22(1):7-20.
PMID: 37906201 DOI: 10.1158/1541-7786.MCR-23-0080

Humans are in a complex symbiotic relationship with a wide range of microbial organisms, including bacteria, viruses, and fungi. The evolution and composition of the human microbiome can be an indicator of how it may affect human health and susceptibility to diseases. Microbiome alteration, termed as dysbiosis, has been linked to the pathogenesis and progression of hematological cancers. A variety of mechanisms, including epithelial barrier disruption, local chronic inflammation response trigger, antigen dis-sequestration, and molecular mimicry, have been proposed to be associated with gut microbiota. Dysbiosis may be induced or worsened by cancer therapies (such as chemotherapy and/or hematopoietic stem cell transplantation) or infection. The use of antibiotics during treatment may also promote dysbiosis, with possible long-term consequences. The aim of this review is to provide a succinct summary of the current knowledge describing the role of the microbiome in hematological cancers, as well as its influence on their therapies. Modulation of the gut microbiome, involving modifying the composition of the beneficial microorganisms in the management and treatment of hematological cancers is also discussed. Additionally discussed are the latest developments in modeling approaches and tools used for computational analyses, interpretation and better understanding of the gut microbiome data.

Matched MeSH terms: Dysbiosis/microbiology; Dysbiosis/therapy
Fulltext Endometrial microbiota composition is associated with reproductive outcome in infertile patients

Moreno I, Garcia-Grau I, Perez-Villaroya D, Gonzalez-Monfort M, Bahçeci M, Barrionuevo MJ, et al.

Microbiome, 2022 Jan 04;10(1):1.
PMID: 34980280 DOI: 10.1186/s40168-021-01184-w

BACKGROUND: Previous evidence indicates associations between the female reproductive tract microbiome composition and reproductive outcome in infertile patients undergoing assisted reproduction. We aimed to determine whether the endometrial microbiota composition is associated with reproductive outcomes of live birth, biochemical pregnancy, clinical miscarriage or no pregnancy.
METHODS: Here, we present a multicentre prospective observational study using 16S rRNA gene sequencing to analyse endometrial fluid and biopsy samples before embryo transfer in a cohort of 342 infertile patients asymptomatic for infection undergoing assisted reproductive treatments.
RESULTS: A dysbiotic endometrial microbiota profile composed of Atopobium, Bifidobacterium, Chryseobacterium, Gardnerella, Haemophilus, Klebsiella, Neisseria, Staphylococcus and Streptococcus was associated with unsuccessful outcomes. In contrast, Lactobacillus was consistently enriched in patients with live birth outcomes.
CONCLUSIONS: Our findings indicate that endometrial microbiota composition before embryo transfer is a useful biomarker to predict reproductive outcome, offering an opportunity to further improve diagnosis and treatment strategies. Video Abstract.

Matched MeSH terms: Dysbiosis/microbiology
Multifaceted role of synbiotics as nutraceuticals, therapeutics and carrier for drug delivery

Khursheed R, Gulati M, Wadhwa S, Vishwas S, Sharma DS, Corrie L, et al.

Chem Biol Interact, 2022 Dec 01;368:110223.
PMID: 36283466 DOI: 10.1016/j.cbi.2022.110223

Synbiotics, are a combination of probiotics and prebiotics. They play an important role in metabolizing different nutritional substrates and thus helps in the maintenance of human health. Any disbalance in the gut microflora, known as dysbiosis, is known to lead to a number of diseased conditions. It can be reverted by the administration of synbiotics. Present review highlights various mechanistic pathways through which synbiotics act as therapeutics. The dual role of synbiotics as nutraceutical and excipient in developing oral formulations are entailed with case studies. The findings entailed that there exist numerous studies on prebiotics as well as probiotics have been carried out to show their effects in several diseases. However, the concept of combining together them for prevention and treatment of various pathological conditions accruing from dysbiosis is relatively new. Synbiotics, however, face challenge of low stability during their sojourn in the GIT, which is generally overcome by various encapsulation techniques. Various studies also showed potential role of synbiotics in drug delivery. However, it is an emerging area and lacks clinical correlation. It is important to focus on clinical trials of formulations wherein synbiotics have been used as therapeutic moiety as well as pharmaceutical carrier for treating various diseases.

Matched MeSH terms: Dysbiosis
Fulltext Effects of Vitamin E on the Gut Microbiome in Ageing and Its Relationship with Age-Related Diseases: A Review of the Current Literature

Gothandapani D, Makpol S

Int J Mol Sci, 2023 Sep 28;24(19).
PMID: 37834115 DOI: 10.3390/ijms241914667

Ageing is inevitable in all living organisms and is associated with physical deterioration, disease and eventually death. Dysbiosis, which is the alteration of the gut microbiome, occurs in individuals during ageing, and plenty of studies support that gut dysbiosis is responsible for the progression of different types of age-related diseases. The economic burden of age-linked health issues increases as ageing populations increase. Hence, an improvement in disease prevention or therapeutic approaches is urgently required. In recent years, vitamin E has garnered significant attention as a promising therapeutic approach for delaying the ageing process and potentially impeding the development of age-related disease. Nevertheless, more research is still required to understand how vitamin E affects the gut microbiome and how it relates to age-related diseases. Therefore, we gathered and summarized recent papers in this review that addressed the impact of the gut microbiome on age-related disease, the effect of vitamin E on age-related disease along with the role of vitamin E on the gut microbiome and the relationship with age-related diseases which are caused by ageing. Based on the studies reported, different bacteria brought on various age-related diseases with either increased or decreased relative abundances. Some studies have also reported the positive effects of vitamin E on the gut microbiome as beneficial bacteria and metabolites increase with vitamin E supplementation. This demonstrates how vitamin E is vital as it affects the gut microbiome positively to delay ageing and the progression of age-related diseases. The findings discussed in this review will provide a simplified yet deeper understanding for researchers studying ageing, the gut microbiome and age-related diseases, allowing them to develop new preclinical and clinical studies.

Matched MeSH terms: Dysbiosis
Dietary patterns in childhood and their effect on gut microbiota-an Asian perspective on atopy risk

Ismail IH, Lay C, H A Majid N, Lee WS, Lee BW, Abdul Latiff AH, et al.

J Allergy Clin Immunol, 2020 11;146(5):1005-1007.
PMID: 32860819 DOI: 10.1016/j.jaci.2020.05.057
Matched MeSH terms: Dysbiosis/epidemiology*
Short Chain Fatty Acids: Fundamental mediators of the gut-lung axis and their involvement in pulmonary diseases

Ashique S, De Rubis G, Sirohi E, Mishra N, Rihan M, Garg A, et al.

Chem Biol Interact, 2022 Dec 01;368:110231.
PMID: 36288778 DOI: 10.1016/j.cbi.2022.110231

The human microbiota is fundamental to correct immune system development and balance. Dysbiosis, or microbial content alteration in the gut and respiratory tract, is associated with immune system dysfunction and lung disease development. The microbiota's influence on human health and disease is exerted through the abundance of metabolites produced by resident microorganisms, where short-chain fatty acids (SCFAs) represent the fundamental class. SCFAs are mainly produced by the gut microbiota through anaerobic fermentation of dietary fibers, and are known to influence the homeostasis, susceptibility to and outcome of many lung diseases. This article explores the microbial species found in healthy human gastrointestinal and respiratory tracts. We investigate factors contributing to dysbiosis in lung illness, and the gut-lung axis and its association with lung diseases, with a particular focus on the functions and mechanistic roles of SCFAs in these processes. The key focus of this review is a discussion of the main metabolites of the intestinal microbiota that contribute to host-pathogen interactions: SCFAs, which are formed by anaerobic fermentation. These metabolites include propionate, acetate, and butyrate, and are crucial for the preservation of immune homeostasis. Evidence suggests that SCFAs prevent infections by directly affecting host immune signaling. This review covers the various and intricate ways through which SCFAs affect the immune system's response to infections, with a focus on pulmonary diseases including chronic obstructive pulmonary diseases, asthma, lung cystic fibrosis, and tuberculosis. The findings reviewed suggest that the immunological state of the lung may be indirectly influenced by elements produced by the gut microbiota. SCFAs represent valuable potential therapeutic candidates in this context.

Matched MeSH terms: Dysbiosis/metabolism
[ABDOMINAL OBESITY AND GUT MICROBIOTA (REVIEW)]

Miloslavsky D, Mysnychenko O, Penkova M, Schenyavska Е, Koval S

Georgian Med News, 2021 9 14.
PMID: 34511461

In review provides data on pathophysiological relationships of intestinal microbiota with body weight regulation in patients with abdominal obesity. In manuscript discusses the leading mechanisms by which the gut microbiota can contribute to obesity and metabolic diseases, analyzes its components, including gastrointestinal peptides, short-chain fatty acids, bile acids, farnesoid receptors, etc. Western diet high in salt, dysbiosis and endotoxemia can be powerful pro-inflammatory factors responsible for the development of insulin resistance and weight gain. It is promising to prescribe agonists of gastrointestinal peptides, probiotics and prebiotics, which in abdominal obesity are able to inhibit dysbiosis, regulate immune functions, and protect the organism from low-intensity chronic inflammation.

Matched MeSH terms: Dysbiosis
Fulltext The Gut-Brain-Axis on the Manifestation of Depressive Symptoms in Epilepsy: An Evidence-Driven Hypothesis

Shaikh MF, Lee CY, Chen WN, Shaikh FA

Front Pharmacol, 2020;11:465.
PMID: 32322213 DOI: 10.3389/fphar.2020.00465

Epilepsy is a severe neurological disorder involving 70 million people around the globe. Epilepsy-related neuropsychiatric comorbidities such as depression, which is the most common, is an additional factor that negatively impacts the living quality of epilepsy patients. There are many theories and complexities associated with both epilepsy and associated comorbidities, one of which is the gut-brain-axis influence. The gut microbiome is hypothesized to be linked with many neurological disorders; however, little conclusive evidence is available in this area. Thus, highlighting the role will create interest in researchers to conduct detailed research in comprehending the influence of gut-brain-axis in the manifestation of depressive symptoms in epilepsy. The hypothesis which is explored in this review is that the gut-brain-axis do play an important role in the genesis of epilepsy and associated depression. The correction of this dysbiosis might be beneficial in treating both epilepsy and related depression. This hypothesis is illustrated through extensive literature discussion, proposed experimental models, and its applicability in the field. There is indirect evidence which revealed some specific bacterial strains that might cause depression in epilepsy.

Matched MeSH terms: Dysbiosis
Fulltext Urbanisation and its associated factors affecting human gut microbiota: where are we heading to?

Abjani F, Madhavan P, Chong PP, Chinna K, Rhodes CA, Lim YAL

Ann Hum Biol, 2023 Feb;50(1):137-147.
PMID: 36650931 DOI: 10.1080/03014460.2023.2170464

CONTEXT: The continuous rise in urbanisation and its associated factors has been reflected in the structure of the human gut ecosystem.
OBJECTIVE: The main focus of this review is to discuss and summarise the major risk factors associated with urbanisation that affect human gut microbiota thus affecting human health.
METHODS: Multiple medical literature databases, namely PubMed, Google, Google Scholar, and Web of Science were used to find relevant materials for urbanisation and its major factors affecting human gut microbiota/microbiome. Both layman and Medical Subject Headings (MeSH) terms were used in the search. Due to the scarcity of the data, no limitation was set on the publication date. Relevant materials in the English language which include case reports, chapters of books, journal articles, online news reports and medical records were included in this review.
RESULTS: Based on the data discussed in the review, it is quite clear that urbanisation and its associated factors have long-standing effects on the human gut microbiota that result in alterations of gut microbial diversity and composition. This is a matter of serious concern as chronic inflammatory diseases are on the rise in urbanised societies.
CONCLUSION: A better understanding of the factors associated with urbanisation will help us to identify and implement new biological and social approaches to prevent and treat diseases and improve health globally by deepening our understanding of these relationships and increasing studies across urbanisation gradients.HIGHLIGHTSHuman gut microbiota have been linked to almost every important function, including metabolism, intestinal homeostasis, immune system, biosynthesis of vitamins, brain processes, and behaviour.However, dysbiosis i.e., alteration in the composition and diversity of gut microbiota is associated with the pathogenesis of many chronic conditions.In the 21st century, urbanisation represents a major demographic shift in developed and developing countries.During this period of urbanisation, humans have been exposed to many environmental exposures, all of which have led to the dysbiosis of human gut microbiota.The main focus of the review is to discuss and summarise the major risk factors associated with urbanisation and how it affects the diversity and composition of gut microbiota which ultimately affects human health.

Matched MeSH terms: Dysbiosis
Exposure to polystyrene nanoplastics induces apoptosis, autophagy, histopathological damage, and intestinal microbiota dysbiosis of the Pacific whiteleg shrimp (Litopenaeus vannamei)

Li Y, Ye Y, Yuan H, Rihan N, Han M, Liu X, et al.

Sci Total Environ, 2024 Apr 01;919:170924.
PMID: 38360329 DOI: 10.1016/j.scitotenv.2024.170924

Nanoplastics (NPs) are widely distributed environmental pollutants that can disrupt intestinal immunity of crustaceans. In this study, the effects of NPs on gut immune enzyme activities, cell morphology, apoptosis, and microbiota diversity of Litopenaeus vannamei were investigated. L. vannamei was exposed to five concentrations of NPs (0, 0.1, 1, 5, and 10 mg/L) for 28 days. The results showed that higher concentrations of NPs damaged the intestinal villi, promoted formation of autophagosomes, increased intestinal non-specific immunoenzyme activities, and significantly increased apoptosis at 10 mg/L. In response to exposure to NPs, the expression levels of ATG3, ATG4, ATG12, Caspase-3, p53, and TNF initially increased and then decreased. In addition, the concentration of NPs was negatively correlated to the expression levels of the genes of interest and intestinal enzyme activities, suggesting that exposure to NPs inhibited apoptosis and immune function. The five dominant phyla of the gut microbiota (Proteobacteria, Firmicutes, Bacteroidetes, Acidobacteria, and Actinomycetes) were similar among groups exposed to different concentrations of NPs, but the abundances tended to differ. Notably, exposure to NPs increased the abundance of pathogenic bacteria. These results confirm that exposure to NPs negatively impacted intestinal immune function of L. vannamei. These findings provide useful references for efficient breeding of L. vannamei.

Matched MeSH terms: Dysbiosis
Ageing and the gut-brain axis: lessons from the Drosophila model

Tan FHP, Shamsuddin S, Zainuddin A

Benef Microbes, 2023 Dec 13;14(6):591-607.
PMID: 38350490 DOI: 10.1163/18762891-20230056

The steady decline of physiological function and increased vulnerability to age-related disorders are two features of the complicated biological process of ageing. As a key organ for nutrient absorption, metabolism, and immunological regulation, the gut plays a major part in the ageing process. Drosophila melanogaster, a well-established model organism, has emerged as a significant tool for exploring the intricate rapport between the gut and ageing. Through the use of Drosophila models, the physiological and molecular elements of the gut-brain axis have been thoroughly explored. These models have also provided insights into the mechanisms by which gut health impacts ageing and age-related illnesses. Drosophila's gut microbiota experience dysbiosis with age which has been linked to age-related diseases. To prevent this and promote healthy ageing in Drosophila, gut microbiota modification methods, such as dietary restriction in tandem with time-restricted feeding, administration of pro-, pre- and synbiotics, as well as pharmaceutical interventions have been generated with positive impacts. The article also covers the drawbacks and difficulties of investigating the gut via the Drosophila. Thus, with an emphasis on the lessons discovered from Drosophila research, this review provides an extensive description of the current studies on the role of the gut-brain axis in ageing and health.

Matched MeSH terms: Dysbiosis
Culture-independent studies on bacterial dysbiosis in oral and oropharyngeal squamous cell carcinoma: A systematic review

Gopinath D, Menon RK, Banerjee M, Su Yuxiong R, Botelho MG, Johnson NW

Crit Rev Oncol Hematol, 2019 Jul;139:31-40.
PMID: 31112880 DOI: 10.1016/j.critrevonc.2019.04.018

Imbalance within the resident bacterial community (dysbiosis), rather than the presence and activity of a single organism, has been proposed to be associated with, and to influence, the development and progression of various diseases; however, the existence and significance of dysbiosis in oral/oropharyngeal cancer is yet to be clearly established. A systematic search (conducted on 25/01/2018 and updated on 25/05/2018) was performed on three databases (Pubmed, Web of Science & Scopus) to identify studies employing culture-independent methods which investigated the bacterial community in oral/oropharyngeal cancer patients compared to control subjects. Of the 1546 texts screened, only fifteen publications met the pre-determined selection criteria. Data extracted from 731 cases and 809 controls overall, could not identify consistent enrichment of any particular taxon in oral/oropharyngeal cancers, although common taxa could be identified between studies. Six studies reported the enrichment of Fusobacteria in cancer at different taxonomic levels whereas four studies reported an increase in Parvimonas. Changes in microbial diversity remained inconclusive, with four studies showing a higher diversity in controls, three studies showing a higher diversity in tumors and three additional studies showing no difference between tumors and controls. Even though most studies identified a component of dysbiosis in oral/oropharyngeal cancer, methodological and analytical variations prevented a standardized summary, which highlights the necessity for studies of superior quality and magnitude employing standardized methodology and reporting. Indeed an holistic metagenomic approach is likely to be more meaningful, as is understanding of the overall metabolome, rather than a mere enumeration of the organisms present.

Matched MeSH terms: Dysbiosis/complications*; Dysbiosis/physiopathology
El Niño Altered Gut Microbiota of Children: A New Insight on Weather-Gut Interactions and Protective Effects of Probiotic

Lau ASY, Mitsuyama E, Odamaki T, Xiao JZ, Liong MT

J Med Food, 2019 Mar;22(3):230-240.
PMID: 30183458 DOI: 10.1089/jmf.2018.4276

Changes in weather often trigger a myriad of negative impacts on the environment, which eventually affect human health. During the early months of 2016, Malaysia experienced El Niño, with an extremely dry season of almost zero rainfall. At the same time, an increase of more than twofold in fecal secretary immunoglobulin-A (SIgA) levels of healthy preschool children aged 2-6 years was observed, accompanied by an increase in phylum Bacteroidetes, predominantly attributed to genus Bacteroides and Odoribacter, which also positively correlated with fecal SIgA levels. Here, we present evidence to illustrate the detrimental effects of weather change on a microscopic "environment," the human gut ecosystem. We also discuss the protective effects of probiotic against dysbiosis as induced by weather change. The increase in Bacteroidetes was at an expense of decreased genus Faecalibacterium and Veillonella (phylum Firmicutes), whereas children consuming probiotic had a decrease in genus Collinsella, Atopobium, and Eggerthella (phylum Actinobacteria) instead.

Matched MeSH terms: Dysbiosis/microbiology; Dysbiosis/prevention & control*
The debate over neurotransmitter interaction in aspartame usage

Choudhary AK, Lee YY

J Clin Neurosci, 2018 Oct;56:7-15.
PMID: 30318075 DOI: 10.1016/j.jocn.2018.06.043

Aspartame (NutraSweet®, Equal®) is a widely used artificial sweetener, has been reported to be accountable for neurological and behavioural disturbances in people. Upon ingestion, aspartame is hydrolyzed in gut and provides its metabolite; such as essential amino acid phenylalanine (Phy) (50%), aspartic acid (40%), and methanol (10%). Altered brain neurochemical compositions [such as dopamine (DA), norepinephrine (NE), and serotonin (5-HT)] have long been a concern and being involved in observed neurophysiological symptom (such as headaches, memory loss, mood changes, as well as depression) in aspartame consumers. Aspartames might act as chemical stressor through increasing plasma cortisol level. Aspartame consumption similarly altered gut microbiota. Taken together all this factors, we reviewed to search for convincing evidence, in what manner aspartame metabolites, stress hormones (cortisol), and gut dysbiosisis involved in altering brain neurochemical composition. We concluded that aspartame metabolite; mainly Phy and its interaction with neurotransmitter and aspartic acid by acting as excitatory neurotransmitter causes this pattern of impairments. Along with elevated cortisol and gut dysbiosis via interactions with different biogenic amine may also have additional impact to modulate neuronal signaling lead to neurobiological impairments. Hence ongoing research is instantly needed to understand the specific roles of aspartame metabolite, elevated cortisol, and gut dysbiosis with emerging neurophysiological symptom in aspartame consumers to improve healthy life in its consumers.

Matched MeSH terms: Dysbiosis/chemically induced; Dysbiosis/metabolism
Fulltext Irritable Bowel Syndrome, Depression, and Neurodegeneration: A Bidirectional Communication from Gut to Brain

Aziz MNM, Kumar J, Muhammad Nawawi KN, Raja Ali RA, Mokhtar NM

Nutrients, 2021 Aug 31;13(9).
PMID: 34578939 DOI: 10.3390/nu13093061

Patients with irritable bowel syndrome (IBS) are increasingly presenting with a wide range of neuropsychiatric symptoms, such as deterioration in gastroenteric physiology, including visceral hypersensitivity, altered intestinal membrane permeability, and gastrointestinal motor dysfunction. Functional imaging of IBS patients has revealed several abnormalities in various brain regions, such as significant activation of amygdala, thinning of insular and anterior cingulate cortex, and increase in hypothalamic gray matter, which results in poor psychiatric and cognitive outcomes. Interrelations between the enteric and central events in IBS-related gastrointestinal, neurological, and psychiatric pathologies have compelled researchers to study the gut-brain axis-a bidirectional communication that maintains the homeostasis of the gastrointestinal and central nervous system with gut microbiota as the protagonist. Thus, it can be disrupted by any alteration owing to the gut dysbiosis or loss of diversity in microbial composition. Available evidence indicates that the use of probiotics as a part of a balanced diet is effective in the management of IBS and IBS-associated neurodegenerative and psychiatric comorbidities. In this review, we delineate the pathogenesis and complications of IBS from gastrointestinal and neuropsychiatric standpoints while also discussing the neurodegenerative events in enteric and central nervous systems of IBS patients and the therapeutic potential of gut microbiota-based therapy established on clinical and preclinical data.

Matched MeSH terms: Dysbiosis/epidemiology*; Dysbiosis/physiopathology
Dietary phytochemicals that influence gut microbiota: Roles and actions as anti-Alzheimer agents

Wang Y, Lim YY, He Z, Wong WT, Lai WF

Crit Rev Food Sci Nutr, 2021 Feb 09.
PMID: 33559482 DOI: 10.1080/10408398.2021.1882381

The last decide has witnessed a growing research interest in the role of dietary phytochemicals in influencing the gut microbiota. On the other hand, recent evidence reveals that dietary phytochemicals exhibit properties of preventing and tackling symptoms of Alzheimer's disease, which is a neurodegenerative disease that has also been linked with the status of the gut microbiota over the last decade. Till now, little serious discussions, however, have been made to link recent understanding of Alzheimer's disease, dietary phytochemicals and the gut microbiota together and to review the roles played by phytochemicals in gut dysbiosis induced pathologies of Alzheimer's disease. Deciphering these connections can provide insights into the development and future use of dietary phytochemicals as anti-Alzheimer drug candidates. This review aims at presenting latest evidence in the modulating role of phytochemicals in the gut microbiota and its relevance to Alzheimer's disease and summarizing the mechanisms behind the modulative activities. Limitations of current research in this field and potential directions will also be discussed for future research on dietary phytochemicals as anti-Alzheimer agents.

Matched MeSH terms: Dysbiosis
Fulltext Parvimonas micra, Peptostreptococcus stomatis, Fusobacterium nucleatum and Akkermansia muciniphila as a four-bacteria biomarker panel of colorectal cancer

Osman MA, Neoh HM, Ab Mutalib NS, Chin SF, Mazlan L, Raja Ali RA, et al.

Sci Rep, 2021 02 03;11(1):2925.
PMID: 33536501 DOI: 10.1038/s41598-021-82465-0

Dysbiosis of the gut microbiome has been associated with the pathogenesis of colorectal cancer (CRC). We profiled the microbiome of gut mucosal tissues from 18 CRC patients and 18 non-CRC controls of the UKM Medical Centre (UKMMC), Kuala Lumpur, Malaysia. The results were then validated using a species-specific quantitative PCR in 40 CRC and 20 non-CRC tissues samples from the UMBI-UKMMC Biobank. Parvimonas micra, Fusobacterium nucleatum, Peptostreptococcus stomatis and Akkermansia muciniphila were found to be over-represented in our CRC patients compared to non-CRC controls. These four bacteria markers distinguished CRC from controls (AUROC = 0.925) in our validation cohort. We identified bacteria species significantly associated (cut-off value of > 5 fold abundance) with various CRC demographics such as ethnicity, gender and CRC staging; however, due to small sample size of the discovery cohort, these results could not be further verified in our validation cohort. In summary, Parvimonas micra, Fusobacterium nucleatum, Peptostreptococcus stomatis and Akkermansia muciniphila were enriched in our local CRC patients. Nevertheless, the roles of these bacteria in CRC initiation and progression remains to be investigated.

Matched MeSH terms: Dysbiosis/complications; Dysbiosis/diagnosis*; Dysbiosis/microbiology

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