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Clinical Psychology Review Feb 2021Growing evidence indicates the community of microorganisms throughout the gastrointestinal tract, (i.e., gut microbiota), is associated with anxiety and depressive... (Review)
Review
Growing evidence indicates the community of microorganisms throughout the gastrointestinal tract, (i.e., gut microbiota), is associated with anxiety and depressive disorders. We present the first systematic review of the gut microbiota in anxiety disorders, along with an update in depression. Consideration of shared underlying features is essential due to the high rates of comorbidity. Systematic searches, following PRISMA guidelines, identified 26 studies (two case-control comparisons of the gut microbiota in generalised anxiety disorder, 18 in depression, one incorporating both anxiety/depression, and five including symptom-only measures). Alpha and beta diversity findings were inconsistent; however, differences in bacterial taxa indicated disorders may be characterised by a higher abundance of proinflammatory species (e.g., Enterobacteriaceae and Desulfovibrio), and lower short-chain fatty acid producing-bacteria (e.g., Faecalibacterium). Several taxa, and their mechanisms of action, may relate to anxiety and depression pathophysiology via communication of peripheral inflammation to the brain. Although the gut microbiota remains a promising target for prevention and therapy, future research should assess confounders, particularly diet and psychotropic medications, and should examine microorganism function.
Topics: Anxiety; Anxiety Disorders; Brain; Depression; Gastrointestinal Microbiome; Humans
PubMed: 33271426
DOI: 10.1016/j.cpr.2020.101943 -
International Journal of Molecular... Apr 2022An emerging body of literature demonstrates differences in the gut microbiome (GMB) of patients with major depressive disorder (MDD) compared to healthy controls (HC),... (Review)
Review
An emerging body of literature demonstrates differences in the gut microbiome (GMB) of patients with major depressive disorder (MDD) compared to healthy controls (HC), as well as the potential benefits of prebiotic, probiotic, and synbiotic treatment. We conducted a systematic review of 24 observational studies (n = 2817), and 19 interventional trials (n = 1119). We assessed alpha diversity, beta diversity, and taxa abundance changes in patients with MDD relative to HC, as well as the effect of prebiotics, probiotics, and synbiotics on depressive symptoms in individuals with clinical or subclinical depression. We observed no significant differences in alpha diversity but a significant difference in beta diversity between patients with MDD and HC. There were fluctuations in the abundance of specific taxa in patients with MDD relative to HC. Probiotic and synbiotic, but not prebiotic, treatment showed a modest benefit in reducing depressive symptoms in patients with MDD over four to nine weeks. The GMB profiles of patients with MDD differ significantly from HC, but further studies are needed to elucidate the benefits of prebiotic, probiotic and synbiotic treatments relative to antidepressants and over longer follow-up before these therapies are implemented into clinical practice.
Topics: Depression; Depressive Disorder, Major; Gastrointestinal Microbiome; Humans; Prebiotics; Probiotics; Synbiotics
PubMed: 35562885
DOI: 10.3390/ijms23094494 -
Journal of Cachexia, Sarcopenia and... Dec 2021Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut-muscle axis has been raised, the casual relationship is still... (Review)
Review
BACKGROUND
Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut-muscle axis has been raised, the casual relationship is still unclear. This systematic review analyses the current evidence of gut microbiota effects on muscle/sarcopenia.
METHODS
A systematic review was performed in PubMed, Embase, Web of Science, and The Cochrane Library databases using the keywords (microbiota* OR microbiome*) AND (sarcopen* OR muscle). Studies reporting the alterations of gut microbiota and muscle/physical performance were analysed.
RESULTS
A total of 26 pre-clinical and 10 clinical studies were included. For animal studies, three revealed age-related changes and relationships between gut microbiota and muscle. Three studies focused on muscle characteristics of germ-free mice. Seventy-five per cent of eight faecal microbiota transplantation studies showed that the recipient mice successfully replicated the muscle phenotype of donors. There were positive effects on muscle from seven probiotics, two prebiotics, and short-chain fatty acids (SCFAs). Ten studies investigated on other dietary supplements, antibiotics, exercise, and food withdrawal that affected both muscle and gut microbiota. Twelve studies explored the potential mechanisms of the gut-muscle axis. For clinical studies, 6 studies recruited 676 elderly people (72.8 ± 5.6 years, 57.8% female), while 4 studies focused on 244 young adults (29.7 ± 7.8 years, 55.4% female). The associations of gut microbiota and muscle had been shown in four observational studies. Probiotics, prebiotics, synbiotics, fermented milk, caloric restriction, and exercise in six studies displayed inconsistent effects on muscle mass, function, and gut microbiota.
CONCLUSIONS
Altering the gut microbiota through bacteria depletion, faecal transplantation, and various supplements was shown to directly affect muscle phenotypes. Probiotics, prebiotics, SCFAs, and bacterial products are potential novel therapies to enhance muscle mass and physical performance. Lactobacillus and Bifidobacterium strains restored age-related muscle loss. Potential mechanisms of microbiome modulating muscle mainly include protein, energy, lipid, and glucose metabolism, inflammation level, neuromuscular junction, and mitochondrial function. The role of the gut microbiota in the development of muscle loss during aging is a crucial area that requires further studies for translation to patients.
Topics: Aged; Animals; Fecal Microbiota Transplantation; Female; Gastrointestinal Microbiome; Humans; Male; Mice; Prebiotics; Sarcopenia; Synbiotics
PubMed: 34523250
DOI: 10.1002/jcsm.12784 -
Advances in Nutrition (Bethesda, Md.) Mar 2022Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences.... (Review)
Review
Vitamin B-12 deficiency is a major public health problem affecting individuals across the lifespan, with known hematological, neurological, and obstetric consequences. Emerging evidence suggests that vitamin B-12 may have an important role in other aspects of human health, including the composition and function of the gastrointestinal (gut) microbiome. Vitamin B-12 is synthesized and utilized by bacteria in the human gut microbiome and is required for over a dozen enzymes in bacteria, compared to only 2 in humans. However, the impact of vitamin B-12 on the gut microbiome has not been established. This systematic review was conducted to examine the evidence that links vitamin B-12 and the gut microbiome. A structured search strategy was used to identify in vitro, animal, and human studies that assessed vitamin B-12 status, dietary intake, or supplementation, and the gut microbiome using culture-independent techniques. A total of 22 studies (3 in vitro, 8 animal, 11 human observational studies) were included. Nineteen studies reported that vitamin B-12 intake, status, or supplementation was associated with gut microbiome outcomes, including beta-diversity, alpha-diversity, relative abundance of bacteria, functional capacity, or short-chain fatty acids (SCFA) production. Evidence suggests that vitamin B-12 may be associated with changes in bacterial abundance. While results from in vitro studies suggest that vitamin B-12 may increase alpha-diversity and shift gut microbiome composition (beta-diversity), findings from animal studies and observational human studies were heterogeneous. Based on evidence from in vitro and animal studies, microbiome outcomes may differ by cobalamin form and co-intervention. To date, few prospective observational studies and no randomized trials have been conducted to examine the effects of vitamin B-12 on the human gut microbiome. The impact of vitamin B-12 on the gut microbiome needs to be elucidated to inform screening and public health interventions.
Topics: Animals; Humans; Gastrointestinal Microbiome; Vitamin B 12; Microbiota; Eating; Bacteria; Vitamins; Observational Studies as Topic
PubMed: 34612492
DOI: 10.1093/advances/nmab123 -
BJOG : An International Journal of... Jan 2020The aetiology and pathogenesis of endometriosis are still under investigation. There is evidence that there is a complex bidirectional interaction between endometriosis...
BACKGROUND
The aetiology and pathogenesis of endometriosis are still under investigation. There is evidence that there is a complex bidirectional interaction between endometriosis and the microbiome.
OBJECTIVE
To systematically review the available literature on the endometriosis-microbiome interaction, with the aim of guiding future inquiries in this emerging area of endometriosis research.
SEARCH STRATEGY
MEDLINE, Embase, Scopus and Web of Science were searched through May 2019. A manual search of reference lists of relevant studies was also performed.
SELECTION CRITERIA
Published and unpublished literature in any language describing a comparison of the microbiome state in mammalian hosts with and without endometriosis.
DATA COLLECTION AND ANALYSIS
Identified studies were screened and assessed independently by two authors. Data were extracted and compiled in a qualitative synthesis of the evidence.
MAIN RESULTS
Endometriosis appears to be associated with an increased presence of Proteobacteria, Enterobacteriaceae, Streptococcus spp. and Escherichia coli across various microbiome sites. The phylum Firmicutes and the genus Gardnerella also appear to have an association; however, this remains unclear.
CONCLUSIONS
The complex bidirectional relationship between the microbiome and endometriosis has begun to be characterised by the studies highlighted in this systematic review. Laboratory and clinical studies demonstrate that there are indeed differences in the microbiome composition of hosts with and without endometriosis.
TWEETABLE ABSTRACT
Review findings show endometriosis associated with increased Proteobacteria, Enterobacteriaceae, Streptococcus and Escherichia coli across various microbiome sites.
Topics: Endometriosis; Female; Gastrointestinal Microbiome; Humans; Menstrual Cycle; Menstruation Disturbances; RNA, Ribosomal, 16S
PubMed: 31454452
DOI: 10.1111/1471-0528.15916 -
Psychoneuroendocrinology Mar 2022The gut microbiota is the set of microorganisms present in the gut, and it is connected to the central nervous system via the gut-brain axis. Despite there is not a... (Review)
Review
The gut microbiota is the set of microorganisms present in the gut, and it is connected to the central nervous system via the gut-brain axis. Despite there is not a definitive description of the eubiotic microbiota architecture, numerous studies have demonstrated its involvement in human behaviour and its relationship with several pathologies. This is a systematic review about the association between dysbiosis on the gut microbiota and the presence of neurological or neuropsychiatric diseases such as cognitive impairment, Alzheimer's disease, Parkinson's disease, ADHD, and depression. Furthermore, this study analyzes the potential benefits of psychobiotics supplementation for these pathologies. Searches were conducted in the electronic databases PubMed and PsycINFO. 17 articles were included in this review, the majority were published after 2019. The results showed that gut dysbiosis predicts the development of these pathologies and influences their pathogenesis. In addition, it was found that different psychobiotics, mainly dietary fibers and probiotics of the Lactobacillus family, improved different cognitive functions such as cognitive performance and induce a reduced cortisol response. Improvement in different cognitive functions is possible when understanding gut microbiota-brain axis, enteric nervous system, neural-immune system, neuroendocrine system, and central nervous system's relationship.
Topics: Brain; Dysbiosis; Gastrointestinal Microbiome; Humans; Microbiota; Probiotics
PubMed: 34942539
DOI: 10.1016/j.psyneuen.2021.105640 -
The vaginal microbiome and the risk of preterm birth: a systematic review and network meta-analysis.Scientific Reports May 2022Preterm birth is a major cause of neonatal morbidity and mortality worldwide. Increasing evidence links the vaginal microbiome to the risk of spontaneous preterm labour... (Meta-Analysis)
Meta-Analysis
Preterm birth is a major cause of neonatal morbidity and mortality worldwide. Increasing evidence links the vaginal microbiome to the risk of spontaneous preterm labour that leads to preterm birth. The aim of this systematic review and network meta-analysis was to investigate the association between the vaginal microbiome, defined as community state types (CSTs, i.e. dominance of specific lactobacilli spp, or not (low-lactobacilli)), and the risk of preterm birth. Systematic review using PubMed, Web of Science, Embase and Cochrane library was performed. Longitudinal studies using culture-independent methods categorizing the vaginal microbiome in at least three different CSTs to assess the risk of preterm birth were included. A (network) meta-analysis was conducted, presenting pooled odds ratios (OR) and 95% confidence intervals (CI); and weighted proportions and 95% CI. All 17 studies were published between 2014 and 2021 and included 38-539 pregnancies and 8-107 preterm births. Women presenting with "low-lactobacilli" vaginal microbiome were at increased risk (OR 1.69, 95% CI 1.15-2.49) for delivering preterm compared to Lactobacillus crispatus dominant women. Our network meta-analysis supports the microbiome being predictive of preterm birth, where low abundance of lactobacilli is associated with the highest risk, and L. crispatus dominance the lowest.
Topics: Female; Humans; Infant, Newborn; Lactobacillus; Lactobacillus crispatus; Microbiota; Network Meta-Analysis; Pregnancy; Premature Birth; Vagina
PubMed: 35562576
DOI: 10.1038/s41598-022-12007-9 -
Nutrients May 2022Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome-gut-brain axis (MGBA). The aim of this... (Review)
Review
BACKGROUND
Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome-gut-brain axis (MGBA). The aim of this systematic review was to identify, categorize, and review clinical evidence supporting medicinal plants for the treatment of mental disorders and studies on their interactions with the gut microbiota.
METHODS
This review included medicinal plants for which clinical studies on depression, sleeping disorders, anxiety, or cognitive dysfunction as well as scientific evidence of interaction with the gut microbiome were available. The studies were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.
RESULTS
Eighty-five studies met the inclusion criteria and covered thirty mental health-related medicinal plants with data on interaction with the gut microbiome.
CONCLUSION
Only a few studies have been specifically designed to assess how herbal preparations affect MGBA-related targets or pathways. However, many studies provide hints of a possible interaction with the MGBA, such as an increased abundance of health-beneficial microorganisms, anti-inflammatory effects, or MGBA-related pathway effects by gut microbial metabolites. Data for , , and indicate that the interaction of their constituents with the gut microbiota could mediate mental health benefits. Studies specifically assessing the effects on MGBA-related pathways are still required for most medicinal plants.
Topics: Anxiety; Anxiety Disorders; Gastrointestinal Microbiome; Humans; Mental Health; Plants, Medicinal
PubMed: 35631252
DOI: 10.3390/nu14102111 -
Experimental Dermatology Oct 2021Seborrheic dermatitis (SD) and dandruff (DF) are common chronic inflammatory skin diseases characterized by recurrent greasy scales, sometimes with erythema and...
Seborrheic dermatitis (SD) and dandruff (DF) are common chronic inflammatory skin diseases characterized by recurrent greasy scales, sometimes with erythema and itchiness. Although the exact pathophysiology of the disease is still unclear, current theories highlight the role of microbes on the skin surface in the pathogenesis of SD. Here, we conducted a systematic review to investigate the skin microbiome alterations in patients with SD/DF. We searched Medline/PubMed, Embase and Web of Science for research studies published in English between 1 January 2000 and 31 December 2020. A total of 12 studies with 706 SD/DF samples and 379 healthy samples were included in this study. The scalp and face were predominated by the fungi of Ascomycota and Basidiomycota and the bacteria of Actinobacteria and Firmicutes. In general, the included studies demonstrated an increased Malassezia restricta/Malassezia globosa ratio and a reduction in the Cutibaterium/Staphylococcus ratio in the setting of SD/DF. Staphylococcus was associated with epidermal barrier damage, including elevated levels of trans-epidermal water loss and pH, while Cutibacterium had a positive correlation with water content. Malassezia was also found to be related to an increased itching score and disease severity. Further studies focusing on the interactions between various microbes and the host and microbes can help us to better understand the pathogenesis of SD/DF.
Topics: Dandruff; Dermatitis, Seborrheic; Humans; Microbiota; Skin
PubMed: 34415635
DOI: 10.1111/exd.14450 -
Journal of Affective Disorders Apr 2020Growing attention has been paid to the field of gut microbiota for mental disorders over the last decade. However, to our knowledge, no studies have conducted systematic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Growing attention has been paid to the field of gut microbiota for mental disorders over the last decade. However, to our knowledge, no studies have conducted systematic reviews on the association between gut microbiota and major depressive disorder (MDD) in both interventional and non-interventional studies.
METHODS
We conducted a systematic review and meta-analysis of 16 studies (10 observational [701 participants] and six interventional trials [302 participants]) examining gut microbiota in patients with MDD. The primary outcome measures were differences in the profile of microbiota in the observational studies, and symptom changes for depression between pre- and post-intervention with probiotics in the interventional trials.
RESULTS
In the observational studies, significant reductions in several taxa at the family and genus levels were observed in patients with MDD compared to non-depressed controls. In the interventional studies with probiotics, a significant improvement was found in depressive symptomatology compared to controls (SMD = -1.62, 95% CI = -2.73 to -0.51, p< 0.01).
LIMITATIONS
Lack of consideration of the effects of diet and pharmacotherapy was a possible limitation.
CONCLUSIONS
Our results indicate that several taxa at the family and genus levels, specifically family Prevotellaceae, genus Corprococcus, and Faecalibacterium, were decreased in MDD compared to non-depressed controls in observational studies, and depressive symptoms were improved compared to controls in interventional studies with probiotics. Due to the limited number of studies, further studies considering diet and pharmacotherapy are needed to explore the relationships between gut microbiota and MDD in humans.
Topics: Depressive Disorder, Major; Diet; Gastrointestinal Microbiome; Humans; Microbiota; Probiotics
PubMed: 32056863
DOI: 10.1016/j.jad.2020.01.102