Unraveling the influence of gut microbes on the mind

Isoalantolactone relieves depression-like behaviors in mice after chronic social defeat stress via the gut-brain axis

RATIONALE

The management of depression continues to be challenging despite the variety of available antidepressants. Herbal medicines are used in many cultures but lack stringent testing to understand their efficacy and mechanism of action. Isoalantolactone (LAT) from Elecampane (Inula helenium) improved the chronic social defeat stress (CSDS)-induced anhedonia-like phenotype in mice comparable to fluoxetine, a selective serotonin reuptake inhibitor (SSRI).

OBJECTIVES

Compare the effects of LAT and fluoxetine on depression-like behaviors in mice exposed to CSDS.

RESULT

The CSDS-induced decrease in protein expression of postsynaptic density (PSD95), brain derived neurotrophic factor (BDNF), and glutamate receptor subunit-1 (GluA1) in the prefrontal cortex was restored by LAT. LAT showed robust anti-inflammatory activity and can lessen the increase in IL-6 and TNF-α caused by CSDS. CSDS altered the gut microbiota at the taxonomic level, resulting in significant changes in α- and β-diversity. LAT treatment reestablished the bacterial abundance and diversity and increased the production of butyric acid in the gut that was inhibited by CSDS. The levels of butyric acid were negatively correlated with the abundance of Bacteroidetes, and positively correlated with those of Proteobacteria and Firmicutes across all treatment groups.

CONCLUSIONS

The current data suggest that, similar to fluoxetine, LAT show antidepressant-like effects in mice exposed to CSDS through the modulation of the gut-brain axis.

Gut microbiota mediated inflammation, neuroendocrine and neurotrophic functions involved in the antidepressant-like effects of diosgenin in chronic restraint stress

BACKGROUND

Diosgenin is a well-known steroid saponin possessing neuroprotective activities. However, it is unknown whether diosgenin could alleviate depression-like symptoms.

METHODS

The antidepressant-like effect of diosgenin was investigated in mice induced by chronic restraint stress. The effects of diosgenin on behaviors, inflammation, neuroendocrine, neurotrophic function, and gut microbiota were evaluated.

RESULTS

The results showed that diosgenin alleviated the depressive-like behaviors in mice. In addition, diosgenin was found to reduce serum concentrations of proinflammatory cytokines and the activity of the hypothalamic-pituitary-adrenal (HPA) axis. Besides, diosgenin could activate hippocampal brain-derived neurotrophic factor (BDNF)/TrkB/ERK/CREB signaling pathway and improve the expression of postsynaptic protein PSD95. Meanwhile, the neurogenesis which was inhibited by chronic restraint stress, was totally reversed by diosgenin. Moreover, diosgenin increased the abundance of phylum Firmicutes and the genus Lactobacillus in stressed mice. The results further showed that diosgenin caused a strong correlation between gut microbiota composition and inflammation, the HPA axis activity, or hippocampus neurotrophic function.

LIMITATIONS

Only male mice were used for evaluation in the present study, which limits the understanding of effects of diosgenin on the both sexes. In addition, the results only indicate microbiota at the phylum or genus mediate the regulation of neuroinflammation, neuroendocrine, and neurotrophic function, but does not elucidate how microbiota modulate the systems via their primary or secondary metabolites.

CONCLUSIONS

The present study shows that diosgenin exerts the antidepressant activity, which is associated with the enhancement of neurotrophic function and the inhibition of inflammatory and neuroendocrine activities via the regulation of gut microbiota.

Orchestrating the fecal microbiota transplantation: Current technological advancements and potential biomedical application

Fecal microbiota transplantation (FMT) has been proved to be an effective treatment for gastrointestinal disorders caused due to microbial disbalance. Nowadays, this approach is being used to treat extragastrointestinal conditions like metabolic and neurological disorders, which are considered to have their provenance in microbial dysbiosis in the intestine. Even though case studies and clinical trials have demonstrated the potential of FMT in treating a variety of ailments, safety and ethical concerns must be answered before the technique is widely used to the community's overall benefit. From this perspective, it is not unexpected that techniques for altering gut microbiota may represent a form of medication whose potential has not yet been thoroughly addressed. This review intends to gather data on recent developments in FMT and its safety, constraints, and ethical considerations.

Restoration of the Original Inhabitants: A Systematic Review on Fecal Microbiota Transplantation for Graft-Versus-Host Disease

A compelling intervention to maintain healthy gut microbiota in graft-versus-host-disease (GVHD) is fecal microbial transplantation (FMT). To examine its role in GVHD, we conducted a systemic literature search using multiple electronic databases. Upon pooling of data, 79 patients from six studies and five case reports were included. Complete remission (CR) occurred in 55.9% of patients, and partial remission (PR) occurred in 26.5% of patients (82.4% overall response rate). A limited number of patients had treatment-related mortality (TRM), while few showed mild gastrointestinal (GI)-related and non-GI adverse effects. None of the studies directly examined the role of FMT in the prevention of GVHD. In conclusion, FMT seems to be a safe and effective strategy for the management of GVHD based on the current evidence. Due to the small number of patients evaluated and the absence of randomized data, one cannot portray FMT as a standard of care yet; however, the low toxicity along with the clinical improvement justifies this modality to be tested in a randomized fashion.

Healthcare providers' perception of faecal microbiota transplantation with clostridium difficile infection and inflammatory bowel disease: a quantitative systematic review

BACKGROUND

Clostridioides difficile infection (CDI) and inflammatory bowel disease (IBD) are global gastroenterological diseases that cause considerable burden on human health, healthcare systems, and society. Faecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides Difficile Infection (rCDI) and a promising therapy for IBD. However, indication for FMT in IBD is still unofficial. Consequently, the National Institute for Health and Care Excellence (NICE) is seeking healthcare providers' advice on whether to update FMT guidelines.

METHODS

A systematic review methodology was adopted for this study. Five databases (CINAHL, MEDLINE, Cochrane Library, Scopus, Web of Science) and grey literature were systematically searched for English language literature to 14 May 2021. The quality of the included studies was then appraised using the Institute for Public Health Sciences cross-sectional studies tool, after which the findings of the studies were narratively synthesised.

RESULTS

Thirteen cross-sectional studies with 4110 validated questionnaire responses were included. Narrative synthesis found that 39.43% of respondents were familiar with FMT (N = 3746, 95%CI = 37.87%-41%), 58.81% of respondents would recommend FMT to their patients (N = 1141, 95%CI = 55.95%-61.67%), 66.67% of respondents considered lack of clinical evidence was the greatest concern regarding FMT (N = 1941, 95%CI = 64.57%-68.77%), and 40.43% respondents would not implement FMT due to concerns about infection transmission (N = 1128, 95%CI = 37.57%-43.29%).

CONCLUSION

Healthcare providers' knowledge of FMT is relatively low and education is an effective strategy to improve it. As knowledge of FMT increases, willingness to recommend it also increases. Strengthening FMT clinical efficacy and reducing infection can enhance its public acceptance, application and popularity. However, further research is required to explore the donor screening procedure.

The interaction between tea polyphenols and host intestinal microorganisms: an effective way to prevent psychiatric disorders

Tea polyphenols (TP) are the most bioactive components in tea extracts. It has been reported that TP can regulate the composition and the function of the intestinal flora. Meanwhile, intestinal microorganisms improve the bioavailability of TP, and the corresponding metabolites of TP can regulate intestinal micro-ecology and promote human health more effectively. The dysfunction of the microbiota-gut-brain axis is the main pathological basis of depression, and its abnormality may be the direct cause and potential influencing factor of psychiatric disorders. The interrelationship between TP and intestinal microorganisms is discussed in this review, which will enable us to better evaluate the potential preventive effects of TP on psychiatric disorders by modulating host intestinal microorganisms.

Are we Ready for a "Microbiome-Guided Behaviour" Approach?

The microbiome is proving to be increasingly important for human brain functioning. A series of recent studies have shown that the microbiome influences the central nervous system in various ways, and consequently acts on the psychological well-being of the individual by mediating, among others, the reactions of stress and anxiety. From a specifically neuroethical point of view, according to some scholars, the particular composition of the microbiome-qua microbial community-can have consequences on the traditional idea of human individuality. Another neuroethical aspect concerns the reception of this new knowledge in relation to clinical applications. In fact, attention to the balance of the microbiome-which includes eating behavior, the use of psychobiotics and, in the treatment of certain diseases, the use of fecal microbiota transplantation-may be limited or even prevented by a biased negative attitude. This attitude derives from a prejudice related to everything that has to do with the organic processing of food and, in general, with the human stomach and intestine: the latter have traditionally been regarded as low, dirty, contaminated and opposed to what belongs to the mind and the brain. This biased attitude can lead one to fail to adequately consider the new anthropological conceptions related to the microbiome, resulting in a state of health, both physical and psychological, inferior to what one might have by paying the right attention to the knowledge available today. Shifting from the ubiquitous high-low metaphor (which is synonymous with superior-inferior) to an inside-outside metaphor can thus be a neuroethical strategy to achieve a new and unbiased reception of the discoveries related to the microbiome.

Effects of Intestinal Microbiota on Brain Development in Humanized Gnotobiotic Mice

Poor growth in the Neonatal Intensive Care Unit is associated with an increased risk for poor neurodevelopmental outcomes for preterm infants, however the mechanism is unclear. The microbiome has increasingly been recognized as a modifiable environmental factor to influence host development. Here we explore the hypothesis that the microbiome influences both growth phenotype and brain development. A germ free mouse transfaunation model was used to examine the effects of preterm infant microbiotas known to induce either high growth or low growth phenotypes on postnatal brain development. The microbiome which induced the low growth phenotype was associated with decreases in the neuronal markers NeuN and neurofilament-L as well as the myelination marker MBP when compared to the microbiome associated with the high growth phenotype. Additionally, poor growth phenotype-associated microbiota was associated with increased neuroinflammation marked by increased Nos1, as well as alteration in IGF-1 pathway including decreased circulating and brain IGF-1, decreased circulating IGFBP3, and increased Igfbp3 brain mRNA expression. This study suggests that growth-associated microbiota can influence early neuron and oligodendrocyte development and that this effect may be mediated by effects on neuroinflammation and circulating IGF-1.

A half century of electronic fetal monitoring and bioethics: silence speaks louder than words

Bioethics abolished the prevailing Hippocratic tenet instructing physicians to make treatment decisions, replacing it with autonomy through informed consent. Informed consent allows the patient to choose treatment after options are explained by the physician. The appearance of bioethics in 1970 coincided with the introduction of electronic fetal monitoring (EFM), which evolved to become the fetal surveillance modality of choice for virtually all women in labor. Autonomy rapidly pervaded all medical procedures, but there was a clear exemption for EFM. Even today, EFM remains immune to the doctrine of informed consent despite continually mounting evidence which proves the procedure is nothing more than myth, illusion and junk science that subjects mothers and babies alike to increased risks of morbidity and mortality. And ethicists have remained utterly silent through a half century of EFM misuse. Our article explores this egregious ethical failure by reviewing EFM's lack of clinical efficacy, discussing the EFM related harm to mothers and babies, and focusing on the reasons that this obstetrical procedure eluded the revolutionary change from the Hippocratic tradition to autonomy through informed consent.

Habitual yoghurt consumption and depressive symptoms in a general population study of 19,596 adults

PURPOSE

Epidemiological studies directly examining the association between habitual yoghurt consumption and mental health remain scarce. The aim of this study is to investigate the association of yoghurt consumption with depressive symptoms in adults.

METHODS

This is a cross-sectional study of 19,596 Chinese adults (mean age 41.2, standard deviation 11.8 years; males, 54.3%). Depressive symptoms were assessed using the Self-Rating Depression Scale (SDS). Dietary intake was obtained through a valid food frequency questionnaire. Multiple logistic regression analysis was conducted to assess the association between yoghurt consumption and depressive symptoms. A number of potential confounders were adjusted in the model.

RESULTS

The prevalence of elevated depressive symptoms was 17.1% (SDS ≥45). The multivariable adjusted odds ratios (95% CI) of having elevated depressive symptoms by increasing levels of yoghurt consumption (1-3 times/week, 4-7 times/week, and  ≥twice/day) were 1.05 (0.96, 1.15), 1.02 (0.91, 1.15), and 2.10 (1.61, 2.73) in comparison with lowest consumption group (<once/week or hardly ever).

CONCLUSIONS

These findings suggest no significant association between habitual yoghurt consumption and self-reported depressive symptoms, while the relatively high frequency of yoghurt consumption (≥twice/day), which was seen in a small subset of subjects, was associated with increased depressive symptoms. These results need to be interpreted with caution because of the cross-sectional nature of the data.

How Chinese clinicians face ethical and social challenges in fecal microbiota transplantation: a questionnaire study

BACKGROUND

Fecal microbiota transplantation (FMT) is reportedly the most effective therapy for relapsing Clostridium Difficile infection (CDI) and a potential therapeutic option for many diseases. It also poses important ethical concerns. This study is an attempt to assess clinicians' perception and attitudes towards ethical and social challenges raised by fecal microbiota transplantation.

METHODS

A questionnaire was developed which consisted of 20 items: four items covered general aspects, nine were about ethical aspects such as informed consent and privacy issues, four concerned social and regulatory issues, and three were about an FMT bank. This was distributed to participants at the Second China gastroenterology and FMT conference in May 2015. Basic descriptive statistical analyses and simple comparative statistical tests were performed.

RESULTS

Nearly three quarters of the 100 respondents were gastro-enterologist physicians. 89% of all respondents believed FMT is a promising treatment modality for some diseases and 88% of whom chose clinical efficacy as the primary reason for recommending FMT. High expectation from patients and pressure on clinicians (33%) was reported as the most frequent reasons for not recommending FMT. The clinicians who had less familiarity with FMT reported significantly more worry related to the dignity and psychological impact of FMT compared to those who have high familiarity with FMT (51.6% vs 27.8%, p = 0.021).More than half of the respondents (56.1%) were concerned about the commercialization of FMT, although almost one in five respondents did not see this as a problem.

CONCLUSIONS

We found most respondents have positive attitudes towards FMT but low awareness of published evidence. Informed consent for vulnerable patients, privacy and protection of donors were perceived as the most challenging ethical aspects of FMT. This study identified areas of limited knowledge and ways of addressing ethical issues and indicates the need to devise the education and training for clinicians on FMT.

Ethical Issues in Fecal Microbiota Transplantation in Practice

Fecal microbiota transplantation (FMT) has demonstrated efficacy and is increasingly being used in the treatment of patients with recurrent Clostridium difficile infection. Despite a lack of high-quality trials to provide more information on the long-term effects of FMT, there has been great enthusiasm about the potential for expanding its applications. However, FMT presents many serious ethical and social challenges that must be addressed as part of a successful regulatory policy response. In this article, we draw on a sample of the scientific and bioethics literatures to examine clusters of ethical and social issues arising in five main areas: (1) informed consent and the vulnerability of patients; (2) determining what a "suitable healthy donor" is; (3) safety and risk; (4) commercialization and potential exploitation of vulnerable patients; and (5) public health implications. We find that these issues are complex and worthy of careful consideration by health care professionals. Desperation of a patient should not be the basis for selecting treatment with FMT, and the patient's interests should always be of paramount concern. Authorities must prioritize development of appropriate and effective regulation of FMT to safeguard patients and donors, promote further research into safety and efficacy, and avoid abuse of the treatment.

The Gut-Brain Axis in Healthy Females: Lack of Significant Association between Microbial Composition and Diversity with Psychiatric Measures

OBJECTIVE

This study examined associations between the composition and diversity of the intestinal microbiota and measures of depression, anxiety, eating disorder psychopathology, stress, and personality in a group of healthy adult females.

METHODS

Female participants (n = 91) ages 19-50 years with BMI 18.5-25 kg/m2 were recruited from central North Carolina between July 2014 and March 2015. Participants provided a single fecal sample and completed an online psychiatric questionnaire that included five measures: (i) Beck Anxiety Inventory; (ii) Beck Depression Inventory-II; (iii) Eating Disorder Examination-Questionnaire; (iv) Perceived Stress Scale; and (v) Mini International Personality Item Pool. Bacterial composition and diversity were characterized by Illumina sequencing of the 16S rRNA gene, and associations were examined using Kendall's tau-b correlation coefficient, in conjunction with Benjamini and Hochberg's False Discovery Rate procedure.

RESULTS

We found no significant associations between microbial markers of gut composition and diversity and scores on psychiatric measures of anxiety, depression, eating-related thoughts and behaviors, stress, or personality in a large cohort of healthy adult females.

DISCUSSION

This study was the first specifically to examine associations between the intestinal microbiota and psychiatric measures in healthy females, and based on 16S rRNA taxonomic abundances and diversity measures, our results do not suggest a strong role for the enteric microbe-gut-brain axis in normal variation on responses to psychiatric measures in this population. However, the role of the intestinal microbiota in the pathophysiology of psychiatric illness may be limited to more severe psychopathology.

Mindfulness-Based Movement: A Polyvagal Perspective

Compelling evidence suggests that physical activity is an effective intervention for cancer survivors, including for those undergoing active cancer treatments. However, to date most evidence has emerged from interventions that have promoted moderate to vigorous physical activity. In this conceptual review, we argue that attention should be given to the entire continuum of physical activity from reducing sedentary behavior to increasing higher levels of physical activity when possible. In addition, considerable evidence in the cancer literature supports the value of mindfulness-based interventions as a means of helping patients and survivors cope with the variety of threats that accompany this disease. Based on the success of these two areas of research, we argue for conceptualizing and promoting physical activity as Mindfulness-Based Movement, using Polyvagal Theory as a theoretical framework to understand the role and value of Mindfulness-Based Movement as a potential intervention for cancer care and control.

Perpetuating Myths, Fables, and Fairy Tales: A Half Century of Electronic Fetal Monitoring

Electronic fetal monitoring (EFM) entered clinical medical practice at the same time bioethics became reality. Bioethics changed the medical ethics landscape by replacing the traditional Hippocratic benign paternalism with patient autonomy, informed consent, beneficence, and nonmaleficence. But EFM use represents the polar opposite of bioethics' revered principles-it has been documented for half a century to be completely ineffectual, used without informed consent, and harmful to mothers and newborns alike. Despite EFM's ethical misuse, there has been no outcry from the bioethical world. Why? This article answers that question, discussing EFM's history and the reasons it was issued an ethics pass. And it explores the reason that even today mothers are still treated with blatant medical paternalism, deprived of autonomy and informed consent, and subjected to real medical risks under the guise that EFM is an essential safety device when in fact it is used almost solely to protect physicians and hospitals from cerebral palsy lawsuits.