Gynecologic Cancers and Lifestyle Medicine
Michelle Tollefson, Nancy Eriksen, Neha Pathak in Improving Women's Health Across the Lifespan, 2021
The human microbiome refers to the microorganisms that live mostly symbiotically within the human host. They can be commensal and pathogenic microorganisms. Human cells have evolved out of certain functions due to the diverse gene products offered to us by the organisms in our body, including the gut, oral cavity, lung, urogenital tract, and skin. It has been estimated there are 3×1013 microbes in the human body, roughly equal to the total number of human somatic cells.60 The composition of the microbiome appears to be individually unique. It is mostly established in early life and plays a very important role in lifelong health.61–65 It is also subject to alterations because of both intrinsic and extrinsic factors (Figure 21.2).
Microbial Involvement in Alzheimer’s Disease
David Perlmutter in The Microbiome and the Brain, 2019
Numerous studies, ranging back decades, have identified the critical pathological and physiological role of the microbiome in human health and disease [13–18]. The human microbiome is a term used to represent all of the microbial cells and their products as well as their genetic material that live on, in, or around humans. It functions by shaping and regulating the structure and molecular profile of our immune system and systems-level inflammatory and metabolic status [14,15]. The human microbiome interacts directly with its host and presents a source for human genetic and metabolic diversity. It evolves alongside lifelong developmental stages in humans and varies across different locations of the world; there are even perceptible changes in different tissues and organs of the same body [15]. Furthermore, increasing evidence suggests that the human microbiome, particularly the gut microbiota, impacts not only the immune diseases of the gastrointestinal (GI) tract, but also neurodegenerative disorders, including Alzheimer’s disease. This chapter will review the role microbes play in the pathophysiology of Alzheimer’s, with a focus on the microbiome–host and gut–brain relationships, as well as the potential for developing microbiome-targeted therapies for this disease.
Stress and the brain-gut axis across the spectrum of digestive disorders
Simon R. Knowles, Laurie Keefer, Antonina A. Mikocka-Walus in Psychogastroenterology for Adults, 2019
The human microbiome is the collective microbiota that live symbiotically within various sites of the body. Predominantly composed of bacteria, the gut microbiota (also known as the intestinal flora; see Handout 5.2 for an introduction to the GI microbiome) is altered in patients with FGID, particularly IBS, and moreover faecal microbiota varies in IBS patients based on the predominant symptom pattern [30]. Most consistent findings have included alterations in the ratio of Firmicutes to Bacteroidetes taxa, and a diminished presence of Lactobacillus and Bifidobacterium [35–37]. While the exact mechanisms by which these alterations in microbiota might lead to symptoms of IBS remain incompletely elucidated, it is suspected that at the local level these bacterial changes my precipitate changes in intestinal inflammation, gut permeability, secretion, visceral nociception, and autonomic tone [30].
Zooming in on the endometrial factor of recurrent implantation failure
Published in Human Fertility, 2022
Chibuzor Ifenatuoha, Babatunde Okewale
The human microbiome represents the total population of microorganisms (bacteria) with their associated genetic materials found in/on the human body. The physiological composition of the endometrial microbiome in asymptomatic and reproductive-age women include an abundant population of Lactobacillus species and the rest being Gardnerella, Prevotella, Atopobium, and Sneathia (Moreno et al., 2016; Moreno & Franasiak, 2017). A balanced endometrial microbiota state is very essential for facilitating successful reproductive outcomes (Moreno & Simon, 2018). An altered endometrial microbiota resulting in a decrease in the abundance of the Lactobacillus in the endometrial fluid has been linked to adverse reproductive outcomes in patients with RIF irrespectively of whether the endometrium is receptive at the time of embryo transfer (Moreno et al., 2016). A typical scenario of this type of dysbiosis (a pathological shift in the balance of the endometrial flora) was illustrated in a study investigating the endometrial microbiome of infertile patients experiencing RIF or recurrent pregnancy loss, which showed that the microbiome present were majorly bacteria from the phyla Firmicutes (containing the genus Staphylococci, Lactobacilli, Streptococci), Bacteroidetes (containing genus Prevotella), and Proteobacteria (containing Escherichia coli and Klebsiella pneumonia) (Verstraelen et al., 2016). Thus, this implies that the percentage of Lactobacilli could be a predictive tool for either a successful or failed outcome in IVF patients (Moreno et al., 2016).
The clinical evidence for postbiotics as microbial therapeutics
Published in Gut Microbes, 2022
Alexis Mosca, Ana Teresa Abreu Y Abreu, Kok Ann Gwee, Gianluca Ianiro, Jan Tack, Thi Viet Ha Nguyen, Colin Hill
The human microbiome is the catalog of all microorganisms inhabiting the human body and their genetic complement.1 When operating optimally, the microbiome plays an important role in human health by supporting protective, metabolic, and immune functions.2 Specifically, the evidence suggests that the relationship between the gut microbiome and intestinal epithelial cells supports mucosal and systemic immunity, neuroendocrine function, and intestinal and extra-intestinal health from infancy to adulthood.3–5 When the microbiome is disrupted, metabolites and toxins are produced and are involved with both intestinal and extraintestinal diseases, including chronic digestive disorders, chronic inflammatory disorders, autoimmunity, allergies, and metabolic syndromes.6,7 Microbiome disruption can also influence disease development in distal organs including the brain, liver, lung, and adipose tissue.7
The Roles of Adjuvant Supplements in Colorectal Cancer Patients on Chemotherapy – Reaping Benefits from Metabolic Crosstalk
Published in Nutrition and Cancer, 2018
Babak Golkhalkhali, Audra Shaleena Paliany, Kin Fah Chin, Retnagowri Rajandram
Probiotics are defined as “live microorganisms which, when administered in an adequate amount, confer a beneficial health effect to the host” (13). A healthy human gut contains an average of 1012 bacteria per gram of luminal content, which makes up the human gut microbiota (14). The interaction between the human microbiome and its host affects an array of functions, including, metabolic, neurological, and immunological functions. In fact, colorectal cancer patients are known to have increased populations of the bacteria Escherichia coli in their stool samples, which are directly correlated to the onset of colitis and the promotion of inflammation (15). Thereby, striking the optimal balance of beneficial bacteria in the human microbiome is crucial. Chemotherapy can disturb the natural balance of the human microbiota, which paves way for colonization by opportunistic pathogens. The administration of probiotics is known to be able to inhibit the overgrowth of these pathogens, thus preventing and alleviating the undesirable side effect that is associated with this overgrowth; infectious diarrhea being the most common (16). The mechanisms of probiotics’ benefits, consists of enhancing gastrointestinal barrier function, change of the gut microbiota by prompting host cell antimicrobial peptides, releasing probiotic antimicrobial factors, challenging for epithelial adherence, and modulating immune system to the benefit of the host (17,18).