Displaying all 11 publications

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  1. Chellappan DK, Sze Ning QL, Su Min SK, Bin SY, Chern PJ, Shi TP, et al.
    Chem Biol Interact, 2019 Sep 01;310:108732.
    PMID: 31276660 DOI: 10.1016/j.cbi.2019.108732
    BACKGROUND: The human body is a home to thousands of microbiotas. It is defined as a community of symbiotic, commensal and pathogenic microorganisms that have existed in all exposed sites of the body, which have co-evolved with diet, lifestyle, genetic factors and immune factors. Human microbiotas have been studied for years on their effects with relation to health and diseases.

    METHODS: Relevant published studies, literature and reports were searched from accessible electronic databases and related institutional databases. We used keywords, viz; microbiome, microbiota, microbiome drug delivery and respiratory disease. Selected articles were carefully read through, clustered, segregated into subtopics and reviewed.

    FINDINGS: The traditional belief of sterile lungs was challenged by the emergence of culture-independent molecular techniques and the recently introduced invasive broncho-alveolar lavage (BAL) sampling method. The constitution of a lung microbiome mainly depends on three main ecological factors, which include; firstly, the immigration of microbes into airways, secondly, the removal of microbes from airways and lastly, the regional growth conditions. In healthy conditions, the microbial communities that co-exist in our lungs can build significant pulmonary immunity and could act as a barrier against diseases, whereas, in an adverse way, microbiomes may interact with other pathogenic bacteriomes and viromes, acting as a cofactor in inflammation and host immune responses, which may lead to the progression of a disease. Thus, the use of microbiota as a target, and as a drug delivery system in the possible modification of a disease state, has started to gain massive attention in recent years. Microbiota, owing to its unique characteristics, could serve as a potential drug delivery system, that could be bioengineered to suit the interest. The engineered microbiome-derived therapeutics can be delivered through BC, bacteriophage, bacteria-derived lipid vesicles and microbe-derived extracellular vesicles. This review highlights the relationships between microbiota and different types of respiratory diseases, the importance of microbiota towards human health and diseases, including the role of novel microbiome drug delivery systems in targeting various respiratory diseases.

    Matched MeSH terms: Microbiota/physiology*
  2. Lee YT, Mohd Ismail NI, Wei LK
    PLoS One, 2021;16(1):e0245038.
    PMID: 33439913 DOI: 10.1371/journal.pone.0245038
    BACKGROUND: Ischemic stroke is one of the non-communicable diseases that contribute to the significant number of deaths worldwide. However, the relationship between microbiome and ischemic stroke remained unknown. Hence, the objective of this study was to perform systematic review on the relationship between human microbiome and ischemic stroke.

    METHODS: A systematic review on ischemic stroke was carried out for all articles obtained from databases until 22nd October 2020. Main findings were extracted from all the eligible studies.

    RESULTS: Eighteen eligible studies were included in the systematic review. These studies suggested that aging, inflammation, and different microbial compositions could contribute to ischemic stroke. Phyla Firmicutes and Bacteroidetes also appeared to manipulate post-stroke outcome. The important role of microbiota-derived short-chain fatty acids and trimethylamine N-oxide in ischemic stroke were also highlighted.

    CONCLUSIONS: This is the first systematic review that investigates the relationship between microbiome and ischemic stroke. Aging and inflammation contribute to differential microbial compositions and predispose individuals to ischemic stroke.

    Matched MeSH terms: Microbiota/physiology*
  3. Clifford MN, Jaganath IB, Ludwig IA, Crozier A
    Nat Prod Rep, 2017 Dec 13;34(12):1391-1421.
    PMID: 29160894 DOI: 10.1039/c7np00030h
    Covering: 2000 up to late 2017This review is focussed upon the acyl-quinic acids, the most studied group within the ca. 400 chlorogenic acids so far reported. The acyl-quinic acids, the first of which was characterised in 1846, are a diverse group of plant-derived compounds produced principally through esterification of an hydroxycinnamic acid and 1l-(-)-quinic acid. Topics addressed in this review include the confusing nomenclature, quantification and characterisation by NMR and MS, biosynthesis and role in planta, and the occurrence of acyl-quinic acids in coffee, their transformation during roasting and delivery to the beverage. Coffee is the major human dietary source world-wide of acyl-quinic acids and consideration is given to their absorption and metabolism in the upper gastrointestinal tract, and the colon where the microbiota play a key role in the formation of catabolites. Evidence on the potential of the in vivo metabolites and catabolites of acyl-quinic acids to promote the consumer's health is evaluated.
    Matched MeSH terms: Microbiota/physiology
  4. Hor YY, Lew LC, Jaafar MH, Lau AS, Ong JS, Kato T, et al.
    Pharmacol Res, 2019 08;146:104312.
    PMID: 31207344 DOI: 10.1016/j.phrs.2019.104312
    Aging is closely associated with altered gut function and composition, in which elderly were reported with reduced gut microbiota diversity and increased incidence of age-related diseases. Probiotics have been shown to exert beneficial health-promoting effects through modulation of intestinal microflora biodiversity, thus the effects of probiotics administration on D-galactose (D-gal) senescence-induced rat were evaluated based on the changes in gut microbiota and metabolomic profiles. Upon senescence induction, the ratio of Firmicutes/ Bacteroidetes was significantly lowered, while treatment with Lactobacillus helveticus OFS 1515 and L. fermentum DR9 increased the ratio at the phylum level (P 
    Matched MeSH terms: Microbiota/physiology*
  5. Abdul Rahim MBH, Chilloux J, Martinez-Gili L, Neves AL, Myridakis A, Gooderham N, et al.
    Acta Diabetol, 2019 May;56(5):493-500.
    PMID: 30903435 DOI: 10.1007/s00592-019-01312-x
    The human gut is a home for more than 100 trillion bacteria, far more than all other microbial populations resident on the body's surface. The human gut microbiome is considered as a microbial organ symbiotically operating within the host. It is a collection of different cell lineages that are capable of communicating with each other and the host and has an ability to undergo self-replication for its repair and maintenance. As the gut microbiota is involved in many host processes including growth and development, an imbalance in its ecological composition may lead to disease and dysfunction in the human. Gut microbial degradation of nutrients produces bioactive metabolites that bind target receptors, activating signalling cascades, and modulating host metabolism. This review covers current findings on the nutritional and pharmacological roles of selective gut microbial metabolites, short-chain fatty acids, methylamines and indoles, as well as discussing nutritional interventions to modulate the microbiome.
    Matched MeSH terms: Microbiota/physiology
  6. Hasyima Omar M, González Barrio R, Pereira-Caro G, Almutairi TM, Crozier A
    Int J Food Sci Nutr, 2021 Jun;72(4):511-517.
    PMID: 33238790 DOI: 10.1080/09637486.2020.1850650
    3',4'-Dihydroxycinnamic acid (aka caffeic acid) is a common dietary component found in a variety of plant-derived food products either in a free form or esterified as in chlorogenic acids such as 5-O-caffeoylquinic acid. The dihydroxycinnamate is produced principally by hydrolysis in the colon of 5-O-caffeoylquinic acid and other caffeoylquinic acid esters, and is catabolised by the resident microbiota prior to absorption. In the present study 3',4'-dihydroxycinnamic acid was incubated in vitro, with or without glucose, under anaerobic conditions with faecal slurries obtained from five volunteers. The main resultant catabolites to accumulate were 3-(3',4'-dihydroxyphenyl)propanoic acid (aka dihydrocaffeic acid), 3-(3'-hydroxyphenyl)propanoic acid and phenylacetic acid. Both the rate of degradation of the hydroxycinnamate substrate and the catabolite profile varied between the faecal samples from the individual volunteers. Overall there was no clear cut effect when glucose was added to incubation medium.
    Matched MeSH terms: Microbiota/physiology*
  7. Johnson D, Letchumanan V, Thurairajasingam S, Lee LH
    Nutrients, 2020 Jul 03;12(7).
    PMID: 32635373 DOI: 10.3390/nu12071983
    The study of human microbiota and health has emerged as one of the ubiquitous research pursuits in recent decades which certainly warrants the attention of both researchers and clinicians. Many health conditions have been linked to the gut microbiota which is the largest reservoir of microbes in the human body. Autism spectrum disorder (ASD) is one of the neurodevelopmental disorders which has been extensively explored in relation to gut microbiome. The utilization of microbial knowledge promises a more integrative perspective in understanding this disorder, albeit being an emerging field in research. More interestingly, oral and vaginal microbiomes, indicating possible maternal influence, have equally drawn the attention of researchers to study their potential roles in the etiopathology of ASD. Therefore, this review attempts to integrate the knowledge of microbiome and its significance in relation to ASD including the hypothetical aetiology of ASD and its commonly associated comorbidities. The microbiota-based interventions including diet, prebiotics, probiotics, antibiotics, and faecal microbial transplant (FMT) have also been explored in relation to ASD. Of these, diet and probiotics are seemingly promising breakthrough interventions in the context of ASD for lesser known side effects, feasibility and easier administration, although more studies are needed to ascertain the actual clinical efficacy of these interventions. The existing knowledge and research gaps call for a more expanded and resolute research efforts in establishing the relationship between autism and microbiomes.
    Matched MeSH terms: Microbiota/physiology*
  8. Erejuwa OO, Sulaiman SA, Ab Wahab MS
    Int J Mol Sci, 2014 Mar 07;15(3):4158-88.
    PMID: 24608927 DOI: 10.3390/ijms15034158
    The gut microbiota plays a number of important roles including digestion, metabolism, extraction of nutrients, synthesis of vitamins, prevention against pathogen colonization, and modulation of the immune system. Alterations or changes in composition and biodiversity of the gut microbiota have been associated with many gastrointestinal tract (GIT) disorders such as inflammatory bowel disease and colon cancer. Recent evidence suggests that altered composition and diversity of gut microbiota may play a role in the increased prevalence of metabolic diseases. This review article has two main objectives. First, it underscores approaches (such as probiotics, prebiotics, antimicrobial agents, bariatric surgery, and weight loss strategies) and their prospects in modulating the gut microbiota in the management of metabolic diseases. Second, it highlights some of the current challenges and discusses areas of future research as it relates to the gut microbiota and metabolic diseases. The prospect of modulating the gut microbiota seems promising. However, considering that research investigating the role of gut microbiota in metabolic diseases is still in its infancy, more rigorous and well-designed in vitro, animal and clinical studies are needed.
    Matched MeSH terms: Microbiota/physiology*
  9. Khosravi Y, Seow SW, Amoyo AA, Chiow KH, Tan TL, Wong WY, et al.
    Sci Rep, 2015;5:8731.
    PMID: 25736205 DOI: 10.1038/srep08731
    Helicobacter pylori, is an invariably commensal resident of the gut microbiome associated with gastric ulcer in adults. In addition, these patients also suffered from a low grade inflammation that activates the immune system and thus increased shunting of energy to host defense mechanisms. To assess whether a H. pylori infection could affect growth in early life, we determined the expression levels of selected metabolic gut hormones in germ free (GF) and specific pathogen-free (SPF) mice with and without the presence of H. pylori. Despite H. pylori-infected (SPFH) mice display alteration in host metabolism (elevated levels of leptin, insulin and peptide YY) compared to non-infected SPF mice, their growth curves remained the same. SPFH mice also displayed increased level of eotaxin-1. Interestingly, GF mice infected with H. pylori (GFH) also displayed increased levels of ghrelin and PYY. However, in contrast to SPFH mice, GFH showed reduced weight gain and malnutrition. These preliminary findings show that exposure to H. pylori alters host metabolism early in life; but the commensal microbiota in SPF mice can attenuate the growth retarding effect from H. pylori observed in GF mice. Further investigations of possible additional side effects of H. pylori are highly warranted.
    Matched MeSH terms: Microbiota/physiology
  10. Lee SC, Tang MS, Lim YA, Choy SH, Kurtz ZD, Cox LM, et al.
    PLoS Negl Trop Dis, 2014 May;8(5):e2880.
    PMID: 24851867 DOI: 10.1371/journal.pntd.0002880
    Soil-transmitted helminths colonize more than 1.5 billion people worldwide, yet little is known about how they interact with bacterial communities in the gut microbiota. Differences in the gut microbiota between individuals living in developed and developing countries may be partly due to the presence of helminths, since they predominantly infect individuals from developing countries, such as the indigenous communities in Malaysia we examine in this work. We compared the composition and diversity of bacterial communities from the fecal microbiota of 51 people from two villages in Malaysia, of which 36 (70.6%) were infected by helminths. The 16S rRNA V4 region was sequenced at an average of nineteen thousand sequences per samples. Helminth-colonized individuals had greater species richness and number of observed OTUs with enrichment of Paraprevotellaceae, especially with Trichuris infection. We developed a new approach of combining centered log-ratio (clr) transformation for OTU relative abundances with sparse Partial Least Squares Discriminant Analysis (sPLS-DA) to enable more robust predictions of OTU interrelationships. These results suggest that helminths may have an impact on the diversity, bacterial community structure and function of the gut microbiota.
    Matched MeSH terms: Microbiota/physiology*
  11. Kerfahi D, Tripathi BM, Dong K, Kim M, Kim H, Ferry Slik JW, et al.
    Microb Ecol, 2019 Jan;77(1):168-185.
    PMID: 29882154 DOI: 10.1007/s00248-018-1215-z
    Comparing the functional gene composition of soils at opposite extremes of environmental gradients may allow testing of hypotheses about community and ecosystem function. Here, we were interested in comparing how tropical microbial ecosystems differ from those of polar climates. We sampled several sites in the equatorial rainforest of Malaysia and Brunei, and the high Arctic of Svalbard, Canada, and Greenland, comparing the composition and the functional attributes of soil biota between the two extremes of latitude, using shotgun metagenomic Illumina HiSeq2000 sequencing. Based upon "classical" views of how tropical and higher latitude ecosystems differ, we made a series of predictions as to how various gene function categories would differ in relative abundance between tropical and polar environments. Results showed that in some respects our predictions were correct: the polar samples had higher relative abundance of dormancy related genes, and lower relative abundance of genes associated with respiration, and with metabolism of aromatic compounds. The network complexity of the Arctic was also lower than the tropics. However, in various other respects, the pattern was not as predicted; there were no differences in relative abundance of stress response genes or in genes associated with secondary metabolism. Conversely, CRISPR genes, phage-related genes, and virulence disease and defense genes, were unexpectedly more abundant in the Arctic, suggesting more intense biotic interaction. Also, eukaryote diversity and bacterial diversity were higher in the Arctic of Svalbard compared to tropical Brunei, which is consistent with what may expected from amplicon studies in terms of the higher pH of the Svalbard soil. Our results in some respects confirm expectations of how tropical versus polar nature may differ, and in other respects challenge them.
    Matched MeSH terms: Microbiota/physiology
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