Fecal Microbiota Therapy With a Focus on Clostridium difficile Infection

Crosstalk between COVID-19 and the gut-brain axis: a gut feeling

The microbes in the gut are crucial for maintaining the body's immune system and overall gut health. However, it is not fully understood how an unstable gut environment can lead to more severe cases of SARS-CoV-2 infection. The gut microbiota also plays a role in the gut-brain axis and interacts with the central nervous system through metabolic and neuroendocrine pathways. The interaction between the microbiota and the host's body involves hormonal, immune, and neural pathways, and any disruption in the balance of gut bacteria can lead to dysbiosis, which contributes to pathogen growth. In this context, we discuss how dysbiosis could contribute to comorbidities that increase susceptibility to SARS-CoV-2. Probiotics and fecal microbiota transplantation have successfully treated infectious and non-infectious inflammatory-related diseases, the most common comorbidities. These treatments could be adjuvant therapies for COVID-19 infection by restoring gut homeostasis and balancing the gut microbiota.

Comprehensive bibliometric and visualized analysis of research on fecal microbial transplantation published from 2000 to 2021

Background

Fecal microbial transplantation has emerged in recent years as a method of treating disease by rebuilding the intestinal flora. However, few bibliometric analyses have systematically studied this area of research. We aimed to use bibliometric analysis to visualize trends and topical research in fecal microbial transplantation to help provide insight into future trends in clinical and basic research.

Materials and methods

Articles and reviews related to fecal microbial transplantation were collected from the Web of Science Core Collection. Significant information associated with this field was visually analyzed by using Biblioshiny and CtieSpace software.

Results

A total of 3144 articles and overviews were included. The number of publications related to fecal microbial transplantation significantly increased yearly. These publications mainly came from 100 countries, led by the US and China, and 521 institutions. The most prolific and influential author is KHORUTS A. The main disciplines and application fields of fecal microbial transplantation included molecular /biology/immunology and medicine/clinical medicine, and the research foundation of fecal microbial transplantation was molecular /biology/genetics and health/nursing/medicine. An alluvial flow visualization showed several landmark articles. New developments were identified in terms of reference and keyword citation bursts. Data analysis showed that different FMT preparation and delivery methods gradually appeared as research hotspots. The main research keywords in the last 3 years were chain fatty acids, Akkermansia muciniphila, and insulin sensitivity, other keywords were current and developing research fields.

Conclusion

Research on fecal microbial transplantation is flourishing and many new applications of fecal microbial transplantation are emerging. Microbial metabolites such as short-chain fatty acids and the microbiota–gut–brain axis have become the focus of current research and are future research trends.

Bacteriophage therapy: Recent developments and applications of a renaissant weapon

Antimicrobial resistance is a global health problem and one of the leading concerns in healthcare sector. Bacteriophages are antibacterial agents ubiquitous in nature. With increase in antibiotic resistance, use of bacteriophages as therapeutics has become resurgent in recent times. This review focuses on the recent developments in phage therapy and its applications with respect to human infections, animal, food and environment. Moreover, use of phage proteins, bioengineered bacteriophages, and phage derived vaccines is also highlighted. Additionally, the limitations and challenges with regard to implementation of phage therapy, host safety and immune responses are also reviewed in this article.

Anti-diarrheal therapeutic potential of diminazene aceturate stimulation of the ACE II/Ang-(1-7)/Mas receptor axis in mice: A trial study

The angiotensin (Ang) II converting enzyme (ACE II) pathway has recently been shown to be associated with several beneficial effects on the body, especially on the cardiac system and gastrointestinal tract. ACE II is responsible for converting Ang II into the active peptide Ang-(1-7), which in turn binds to a metabotropic receptor, the Mas receptor (MasR). Recent studies have demonstrated that Diminazene Aceturate (DIZE), a trypanosomicide used in animals, activates the ACE II pathway. In this study, we aimed to evaluate the antidiarrheal effects promoted by the administration of DIZE to activate the ACE II/Ang-(1-7)/MasR axis in induced diarrhea mice models. The results show that activation of the ACE II pathway exerts antidiarrheal effects that reduce total diarrheal stools and enteropooling. In addition, it increases Na⁺/K⁺-ATPase activity and reduces gastrointestinal transit and thus inhibits contractions of intestinal smooth muscle; decreases transepithelial electrical resistance, epithelial permeability, PGE2-induced diarrhea, and proinflammatory cytokines; and increases anti-inflammatory cytokines. Enzyme-linked immunosorbent assay (ELISA) demonstrated that DIZE, when activating the ACE II/Ang-(1-7)/MasR axis, can still interact with GM1 receptors, which reduces cholera toxin-induced diarrhea. Therefore, activation of the ACE II/Ang-(1-7)/MasR axis can be an important pharmacological target for the treatment of diarrheal diseases.

Significance of Complement System in Ischemic Stroke: A Comprehensive Review

The complement system is an essential part of innate immunity, typically conferring protection via eliminating pathogens and accumulating debris. However, the defensive function of the complement system can exacerbate immune, inflammatory, and degenerative responses in various pathological conditions. Cumulative evidence indicates that the complement system plays a critical role in the pathogenesis of ischemic brain injury, as the depletion of certain complement components or the inhibition of complement activation could reduce ischemic brain injury. Although multiple candidates modulating or inhibiting complement activation show massive potential for the treatment of ischemic stroke, the clinical availability of complement inhibitors remains limited. The complement system is also involved in neural plasticity and neurogenesis during cerebral ischemia. Thus, unexpected side effects could be induced if the systemic complement system is inhibited. In this review, we highlighted the recent concepts and discoveries of the roles of different kinds of complement components, such as C3a, C5a, and their receptors, in both normal brain physiology and the pathophysiology of brain ischemia. In addition, we comprehensively reviewed the current development of complement-targeted therapy for ischemic stroke and discussed the challenges of bringing these therapies into the clinic. The design of future experiments was also discussed to better characterize the role of complement in both tissue injury and recovery after cerebral ischemia. More studies are needed to elucidate the molecular and cellular mechanisms of how complement components exert their functions in different stages of ischemic stroke to optimize the intervention of targeting the complement system.

Bacteriophages Synergize with the Gut Microbial Community To Combat Salmonella

Antibiotic-resistant bacteria are a global threat. Therefore, alternative approaches for combatting bacteria, especially antibiotic-resistant bacteria, are urgently needed. Using a human gut microbiota model, we demonstrate that bacteriophages (phages) are able to substantially decrease pathogenic Salmonella without perturbing the microbiota. Conversely, antibiotic treatment leads to the eradication of close to all commensal bacteria, leaving only antibiotic-resistant bacteria. An unbalanced microbiota has been linked to many diseases both in the gastrointestinal tract or “nonintestinal” diseases. In our study, we show that the microbiota provides a protective effect against Salmonella. Since phage treatment preserves the healthy gut microbiota, it is a feasible superior alternative to antibiotic treatment. Furthermore, when combating infections caused by pathogenic bacteria, gut microbiota should be considered.

Salmonella infection is one of the main causes of food-borne diarrheal diseases worldwide. Although most Salmonella infections can be cleared without treatment, some cause serious illnesses that require antibiotic treatment. In view of the growing emergence of antibiotic-resistant Salmonella strains, novel treatments are increasingly required. Furthermore, there is a striking paucity of data on how a balanced human gut microbiota responds to Salmonella infection. This study aimed to evaluate whether a balanced gut microbiota protects against Salmonella growth and to compare two antimicrobial approaches for managing Salmonella infection: bacteriophage (phage) treatment and antibiotic treatment. Anaerobically cultivated human intestinal microflora (ACHIM) is a feasible model for the human gut microbiota and naturally inhibits Salmonella infection. By mimicking Salmonella infection in vitro using ACHIM, we observed a large reduction of Salmonella growth by the ACHIM itself. Treatments with phage and antibiotic further inhibited Salmonella growth. However, phage treatment had less impact on the nontargeted bacteria in ACHIM than the antibiotic treatment did. Phage treatment has high specificity when combating Salmonella infection and offers a noninvasive alternative to antibiotic treatment.

IMPORTANCE Antibiotic-resistant bacteria are a global threat. Therefore, alternative approaches for combatting bacteria, especially antibiotic-resistant bacteria, are urgently needed. Using a human gut microbiota model, we demonstrate that bacteriophages (phages) are able to substantially decrease pathogenic Salmonella without perturbing the microbiota. Conversely, antibiotic treatment leads to the eradication of close to all commensal bacteria, leaving only antibiotic-resistant bacteria. An unbalanced microbiota has been linked to many diseases both in the gastrointestinal tract or “nonintestinal” diseases. In our study, we show that the microbiota provides a protective effect against Salmonella. Since phage treatment preserves the healthy gut microbiota, it is a feasible superior alternative to antibiotic treatment. Furthermore, when combating infections caused by pathogenic bacteria, gut microbiota should be considered.

Author Video: An author video summary of this article is available.

Exploration of Fecal Microbiota Transplantation in the Treatment of Refractory Diarrhea After Renal Transplantation

OBJECTIVE

Exploration of fecal microbiota transplantation in the treatment of refractory diarrhea after renal transplantation.

METHODS

Summarize the etiology of 120 cases with diarrhea after renal transplantation from 2014 to 2017 in our hospital. There were 4 recipients of refractory diarrhea who accepted fecal microbiota transplantation with informed consent, and we collected clinical data of stool and bacterial culture, gut microbiota analysis, graft function, electrolytes, immunosuppressant concentrations of prognostic evaluation of patients with fecal transplantation.

RESULTS

The absorption of electrolyte is slightly higher and concentration of tacrolimus and creatinine were not significantly changed compared with before.

CONCLUSION

Fecal microbiota transplantation provides a new choice to refractory diarrhea after renal transplantation as an innovative treatment, but the effectiveness of fecal microbiota transplantation needs long-term observation and further evaluation through large sample data.

The Gut and Its Microbiome as Related to Central Nervous System Functioning and Psychological Well-being: Introduction to the Special Issue of Psychosomatic Medicine

Accumulating evidence indicates bidirectional associations between the brain and the gut microbiome with both top-down and bottom-up processes. This article describes new developments in brain-gut interactions as an introduction to a special issue of Psychosomatic Medicine, based on a joint symposium of the American Psychosomatic Society and the American Gastroenterological Association. Literature review articles indicate that several psychiatric disorders are associated with altered gut microbiota, whereas evidence linking functional gastrointestinal disorders and dysbiosis has not been firmly established. The association between dysbiosis with obesity, metabolic syndrome, and Type 2 diabetes mellitus is still inconclusive, but evidence suggests that bariatric surgery may favorably alter the gut microbial community structure. Consistent with the literature linking psychiatric disorders with dysbiosis is that life adversity during childhood and certain temperaments that develop early in life are associated with altered gut microbiota, particularly the Prevotella species. Some studies reported in this issue support the hypothesis that brain-gut interactions are adversely influenced by reduced functional activation of the hippocampus and autonomic nervous system dysregulation. The evidence for the effects of probiotics in the treatment of Clostridium difficile colitis is relatively well established, but effects on mental health and psychophysiological stress reactivity are either inconclusive or still in progress. To conceptualize brain-gut interactions, a holistic, systems-based perspective on health and disease is needed, integrating gut microbial with environmental ecology. More translational research is needed to examine the mental and physical health effects of prebiotics and probiotics, in well-phenotyped human populations with sufficiently large sample sizes.