The involvement of the microbiota-gut-brain axis in the pathophysiology of mood disorders and therapeutic implications.

INTRODUCTION: There is a growing body of evidence implicating gut-brain axis dysfunction in the pathophysiology of mood disorders. Accordingly, gut microbiota has become a promising target for the development of biomarkers and novel therapeutics for bipolar and depressive disorders. AREAS COVERED: We describe the observed changes in the gut microbiota of patients with mood disorders and discuss the available studies assessing microbiota-based strategies for their treatment. EXPERT OPINION: Microbiota-targeted interventions, such as symbiotics, prebiotics, paraprobiotics, and fecal microbiota transplants seem to attenuate the severity of depressive symptoms. The available results must be seen as preliminary and need to be replicated and/or confirmed in larger and independent studies, also considering the pathophysiological and clinical heterogeneity of mood disorders.

Fecal microbiota transplantation from protozoa-exposed donors downregulates immune response in a germ-free mouse model, its role in immune response and physiology of the intestine.

Intestinal parasites are part of the intestinal ecosystem and have been shown to establish close interactions with the intestinal microbiota. However, little is known about the influence of intestinal protozoa on the regulation of the immune response. In this study, we analyzed the regulation of the immune response of germ-free mice transplanted with fecal microbiota (FMT) from individuals with multiple parasitic protozoans (P) and non-parasitized individuals (NP). We determined the production of intestinal cytokines, the lymphocyte populations in both the colon and the spleen, and the genetic expression of markers of intestinal epithelial integrity. We observed a general downregulation of the intestinal immune response in mice receiving FMT-P. We found significantly lower intestinal production of the cytokines IL-6, TNF, IFN-γ, MCP-1, IL-10, and IL-12 in the FMT-P. Furthermore, a significant decrease in the proportion of CD3+, CD4+, and Foxp3+ T regulatory cells (Treg) was observed in both, the colon and spleen with FMT-P in contrast to FMT-NP. We also found that in FMT-P mice there was a significant decrease in tjp1 expression in all three regions of the small intestine; ocln in the ileum; reg3γ in the duodenum and relmß in both the duodenum and ileum. We also found an increase in colonic mucus layer thickness in mice colonized with FMT-P in contrast with FMT-NP. Finally, our results suggest that gut protozoa, such as Blastocystis hominis, Entamoeba coli, Endolimax nana, Entamoeba histolytica/E. dispar, Iodamoeba bütschlii, and Chilomastix mesnili consortia affect the immunoinflammatory state and induce functional changes in the intestine via the gut microbiota. Likewise, it allows us to establish an FMT model in germ-free mice as a viable alternative to explore the effects that exposure to intestinal parasites could have on the immune response in humans.

Gut Microbiota Disruption in Hematologic Cancer Therapy: Molecular Insights and Implications for Treatment Efficacy.

Hematologic malignancies (HMs), including leukemia, lymphoma, and multiple myeloma, involve the uncontrolled proliferation of abnormal blood cells, posing significant clinical challenges due to their heterogeneity and varied treatment responses. Despite recent advancements in therapies that have improved survival rates, particularly in chronic lymphocytic leukemia and acute lymphoblastic leukemia, treatments like chemotherapy and stem cell transplantation often disrupt gut microbiota, which can negatively impact treatment outcomes and increase infection risks. This review explores the complex, bidirectional interactions between gut microbiota and cancer treatments in patients with HMs. Gut microbiota can influence drug metabolism through mechanisms such as the production of enzymes like bacterial ß-glucuronidases, which can alter drug efficacy and toxicity. Moreover, microbial metabolites like short-chain fatty acids can modulate the host immune response, enhancing treatment effectiveness. However, therapy often reduces the diversity of beneficial bacteria, such as Bifidobacterium and Faecalibacterium, while increasing pathogenic bacteria like Enterococcus and Escherichia coli. These findings highlight the critical need to preserve microbiota diversity during treatment. Future research should focus on personalized microbiome-based therapies, including probiotics, prebiotics, and fecal microbiota transplantation, to improve outcomes and quality of life for patients with hematologic malignancies.

Fecal microbiota transplantation through colonoscopy in the treatment of recurrent Clostridioides difficile: Experience at a university center.

INTRODUCTION: The majority of cases of Clostridioides difficile infection (CDI) respond to antibiotic treatment. Fecal microbiota transplantation (FMT) has been accepted as an effective treatment in cases of recurrent CDI. AIM: Our aim was to describe the clinical results of FMT performed for the treatment of recurrent CDI. MATERIAL AND METHODS: The study was conducted on patients with recurrent CDI treated with FMT through colonoscopy, within the time frame of January 2021 and December 2023. Demographic and clinical data were collected, including pre-FMT treatment data, the FMT success rate, and clinical progression during follow-up. Telephone surveys were carried out to evaluate satisfaction. RESULTS: Thirteen patients with a mean age of 55 years underwent FMT (including 7 patients above 65 years of age and one pregnant woman). Patients presented with a median of 3 previous episodes of CDI (range 2-4). The median time interval from first episode of CDI to FMT was 4 months (range 3-10). The effectiveness of a single FMT session was 100%. During post-FMT follow-up (median of 11 months, range 3-32), 3 patients have presented with a new CDI episode, and a successful second FMT was performed on 2 of them. No adverse events were registered, and all patients had a positive perception of FMT. CONCLUSIONS: In the present study, despite its small size, FMT through colonoscopy was shown to be a safe, effective, and lasting therapy in cases of recurrent CDI, concurring with results from larger studies.

Insights into Gut Dysbiosis: Inflammatory Diseases, Obesity, and Restoration Approaches.

The gut microbiota is one of the most critical factors in human health. It involves numerous physiological processes impacting host health, mainly via immune system modulation. A balanced microbiome contributes to the gut's barrier function, preventing the invasion of pathogens and maintaining the integrity of the gut lining. Dysbiosis, or an imbalance in the gut microbiome's composition and function, disrupts essential processes and contributes to various diseases. This narrative review summarizes key findings related to the gut microbiota in modern multifactorial inflammatory conditions such as ulcerative colitis or Crohn's disease. It addresses the challenges posed by antibiotic-driven dysbiosis, particularly in the context of C. difficile infections, and the development of novel therapies like fecal microbiota transplantation and biotherapeutic drugs to combat these infections. An emphasis is given to restoration of the healthy gut microbiome through dietary interventions, probiotics, prebiotics, and novel approaches for managing gut-related diseases.

Fecal microbiota transplantation ameliorates high-fat diet-induced memory impairment in mice.

Gut dysbiosis is linked to metabolic and neurodegenerative diseases and comprises a plausible link between high-fat diet (HFD) and brain dysfunction. Here we show that gut microbiota modulation by either antibiotic treatment for 5 weeks or a brief 3-day fecal microbiota transplantation (FMT) regimen from low-fat (control) diet-fed mice decreased weight gain, adipose tissue hypertrophy, and glucose intolerance induced by HFD in C57BL/6 male mice. Notably, gut microbiota modulation by FMT completely reversed impaired recognition memory induced by HFD, whereas modulation by antibiotics had less pronounced effect. Improvement in recognition memory by FMT was accompanied by decreased HFD-induced astrogliosis in the hippocampal cornu ammonis region. Gut microbiome composition analysis indicated that HFD diminished microbiota diversity compared to control diet, whereas FMT partially restored the phyla diversity. Our findings reinforce the role of the gut microbiota on HFD-induced cognitive impairment and suggest that modulating the gut microbiota may be an effective strategy to prevent metabolic and cognitive dysfunction associated with unfavorable dietary patterns.

Changes in the Progression of Chronic Kidney Disease in Patients Undergoing Fecal Microbiota Transplantation.

Chronic kidney disease (CKD) is a progressive loss of renal function in which gut dysbiosis is involved. Fecal microbiota transplantation (FMT) may be a promising alternative for restoring gut microbiota and treating CKD. This study evaluated the changes in CKD progression in patients treated with FMT. Patients with diabetes and/or hypertension with CKD clinical stages 2, 3, and 4 in this single-center, double-blind, randomized, placebo-controlled clinical trial (NCT04361097) were randomly assigned to receive either FMT or placebo capsules for 6 months. Laboratory and stool metagenomic analyses were performed. A total of 28 patients were included (15 FMT and 13 placebo). Regardless of CKD stages, patients responded similarly to FMT treatment. More patients (53.8%) from the placebo group progressed to CKD than the FMT group (13.3%). The FMT group maintained stable renal function parameters (serum creatinine and urea nitrogen) compared to the placebo group. Adverse events after FMT treatment were mild or moderate gastrointestinal symptoms. The abundance of Firmicutes and Actinobacteria decreased whereas Bacteroidetes, Proteobacteria and Roseburia spp. increased in the FMT group. CKD patients showed less disease progression after FMT administration. The administration of oral FMT in patients with CKD is a safe strategy, does not represent a risk, and has potential benefits.

Bacterial microbiome changes after fecal transplantation for recurrent Clostridioides difficile infection in the Brazilian center.

Clostridioides difficile infection (CDI) poses a significant global health threat owing to its substantial morbidity and associated healthcare costs. A key challenge in controlling CDI is the risk of multiple recurrences, which can affect up to 30% of patients. In such instances, fecal microbiota transplantation (FMT) is increasingly recognized as the optimal treatment. However, few related studies have been conducted in developing countries, and the microbiota composition of Brazilian patients and its dynamic modification post-FMT remain largely unexplored. This study aimed to evaluate the changes in the bacterial gut microbiome in Brazilian patients with recurrent CDI post-FMT. Ten patients underwent FMT, and the primary and overall CDI resolution rates were 80% and 90% after the first and second FMT, respectively. FMT was associated with an early increase in Shannon's diversity, evident as soon as 1 week post-FMT and persisting for at least 25 days post-treatment. Post-treatment, the abundance of Firmicutes increased and that of Proteobacteria decreased. Specifically, the abundance of the genera Ruminococcus, Faecalibacterium, Lachnospira, and Roseburia of the Firmicutes phylum was significantly higher 1 week post-transplantation, with Ruminococcus and Faecalibacterium remaining enriched 25 days post-transplantation. This study is the first of its kind in Brazil to evaluate the microbiota of a donor and patients undergoing FMT. Our findings suggest that FMT can induce remarkable changes in the gut microbiota, characterized by an early and sustained increase in diversity lasting at least 25 days. FMT also promotes enrichment of genera such as Ruminococcus spp., Faecalibacterium spp., and Roseburia spp., essential for therapeutic success.

Rol de la microbiota intestinal y el estroboloma en el síndrome de ovario poliquístico (SOP) / Role of gut microbiota and the estrobolome in polycystic ovary syndrome (PCOS)

El síndrome de ovario poliquístico (SOP) es un trastorno frecuente en mujeres en edad fértil que se caracteriza por el exceso de andrógenos, oligo/anovulación y/o la presencia de morfología de ovarios poliquísticos. La patogénesis del SOP no se ha dilucidado y se ha propuesto que la microbiota intestinal puede desempeñar un rol clave en este síndrome, debido al impacto de la microbiota en el metabolismo de los lípidos, la glucosa y los esteroides. El principal objetivo de esta revisión es dilucidar la función de la microbiota intestinal y sus metabolitos derivados en la patogénesis del síndrome, así como también, aportar con nuevas ideas para su tratamiento.

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in childbearing age women characterized by androgen excess, oligo/anovulation, and polycystic ovarian morphology. The specific pathogenesis of PCOS has not been elucidated and it has been proposed that gut microbiota may play a key role in PCOS, due to its role on lipid, glucose, and steroid metabolism. The main objective of this review is to elucidate the function of gut microbiota and derived metabolites in the pathogenesis and provide new ideas for treatment.

Gut Microbiota Interventions to Retain Residual Kidney Function.

Residual kidney function for patients with chronic kidney disease (CKD) is associated with better quality of life and outcome; thus, strategies should be implemented to preserve kidney function. Among the multiple causes that promote kidney damage, gut dysbiosis due to increased uremic toxin production and endotoxemia need attention. Several strategies have been proposed to modulate the gut microbiota in these patients, and diet has gained increasing attention in recent years since it is the primary driver of gut dysbiosis. In addition, medications and faecal transplantation may be valid strategies. Modifying gut microbiota composition may mitigate chronic kidney damage and preserve residual kidney function. Although various studies have shown the influential role of diet in modulating gut microbiota composition, the effects of this modulation on residual kidney function remain limited. This review discusses the role of gut microbiota metabolism on residual kidney function and vice versa and how we could preserve the residual kidney function by modulating the gut microbiota balance.

Actualización en el diagnóstico y manejo de la Infección por Clostridioides difficile / Update in diagnosis and management of Clostridioides difficile

El Clostridioides difficile (C. difficile) es una de las principales causas de infección asociada a la atención de salud con una elevada morbimortalidad, sobre todo en adultos mayores hospitalizados. El aumento en el uso de antibióticos ha ido de la mano con el incremento en el número de casos y de una mayor virulencia. Su presentación clínica va desde portadores asintomáticos hasta megacolon tóxico, escenarios que deben ser considerados al momento de realizar el estudio con exámenes de deposiciones (glutamato deshidrogenasa, toxinas A y B y técnicas de amplificación ácidos nucleares). Se han incorporado al arsenal terapéutico, con mayor nivel de evidencia, la fidaxomicina, trasplante microbiota fecal y recientemente nuevas terapias como anticuerpos monoclonales. Sin embargo, la gravedad de la infección, comorbilidad del paciente, presencia factores de recurrencia, el acceso y el costo económico de cada una de las opciones terapéuticas deben ser considerados. El objetivo de esta revisión es actualizar el manejo propuesto por las Sociedades Chilenas de Gastroenterología e Infectología publicadas el 2016 incorporando las últimas recomendaciones con respecto a prevención, diagnóstico y tratamiento de la infección por C. difficile.

Clostridioides difficile (C. difficile) is one of the leading causes of infection associated with health care with high morbidity and mortality, especially among hospitalized older adults. The increase in the use of antibiotics has been associated with a higher number of cases and greater virulence. Its clinical presentation ranges from asymptomatic carriers to toxic megacolon. Studies with stool tests (glutamate dehydrogenase, toxins A and B, and nuclear acid amplification techniques) should be considered in these cases. Fidaxomicin, fecal microbiota transplant, and new therapies such as monoclonal antibodies have been incorporated into the therapeutic arsenal, with a higher level of evidence. Nevertheless, the severity, patient comorbidity, recurrence risk factors, and the economic cost of each therapeutic option must be considered. This review aims to update the last guidelines proposed by the Chilean Societies of Gastroenterology and Infectious Diseases published in 2016, providing the latest recommendations regarding prevention, diagnosis, and treatment of C. difficile infection.

Fecal microbiota transplantation and its repercussions in patients with melanoma refractory to anti-PD-1 therapy: scope review.

INTRODUCTION: despite being extremely effective in some cases, up to 70% of patients with melanoma do not respond to anti-PD-1/PD-L1 (primary resistance) and many of the responders eventually progress (secondary resistance). Extensive efforts are being made to overcome this resistance through new strategies, especially aimed at modulating the intestinal microbiota. OBJECTIVE: to assess whether fecal microbiota transplantation (FMT), associated with immunotherapy, is beneficial in the clinical course of patients with refractory melanoma. METHODS: this is a scope review, based on studies collected on the MEDLINE, ScienceDirect, The Cochrane Library, Embase and BMJ Journals; using the terms: "Antibodies, Monoclonal"; "Drug Resistance, Neoplasm"; "Fecal Microbiota Transplantation"; "Host Microbial Interactions"; "Immunotherapy"; "Melanoma"; and "Microbiota". Clinical trials, in English, with relevant data on the subject and fully available were included. A cut-off period was not determined, due to the limited amount of evidence on the topic. RESULTS: crossing the descriptors allowed the identification of 342 publications and, after applying the eligibility criteria, allowed the selection of 4 studies. From the analyses, it was observed that a considerable part of those studied overcame resistance to immune checkpoint inhibitors after FMT, with better response to treatment, less tumor growth and increased beneficial immune response. CONCLUSION: it is noted that FMT favors the response of melanoma to immunotherapy, translated into significant clinical benefit. However, further studies are necessary for the complete elucidation of the bacteria and the mechanisms involved, as well as for the translation of new evidence to oncological care practice.

[Update in diagnosis and management of Clostridioides difficile]. / Actualización en el diagnóstico y manejo de la Infección por Clostridioides difficile.

Clostridioides difficile (C. difficile) is one of the leading causes of infection associated with health care with high morbidity and mortality, especially among hospitalized older adults. The increase in the use of antibiotics has been associated with a higher number of cases and greater virulence. Its clinical presentation ranges from asymptomatic carriers to toxic megacolon. Studies with stool tests (glutamate dehydrogenase, toxins A and B, and nuclear acid amplification techniques) should be considered in these cases. Fidaxomicin, fecal microbiota transplant, and new therapies such as monoclonal antibodies have been incorporated into the therapeutic arsenal, with a higher level of evidence. Nevertheless, the severity, patient comorbidity, recurrence risk factors, and the economic cost of each therapeutic option must be considered. This review aims to update the last guidelines proposed by the Chilean Societies of Gastroenterology and Infectious Diseases published in 2016, providing the latest recommendations regarding prevention, diagnosis, and treatment of C. difficile infection.

Trasplante de microbiota fecal por colonoscopía en una mujer embarazada con infección recurrente por Clostridioides difficile / Fecal microbiota transplantation through colonoscopy for Clostridioides difficile recurrent infection in a pregnant woman

El diagnóstico de la infección por Clostridioides dfficile (ICD) ha aumentado en el embarazo y periparto. Cambios fisiológicos e inmunológicos normales durante el embarazo pueden incrementar el riesgo de ICD. Mujeres embarazadas con ICD tienen una mayor frecuencia de fracaso al tratamiento y una significativa morbilidad y mortalidad. El trasplante de microbiota fecal (TMF) se ha convertido en el tratamiento estándar de la ICD recurrente y refractaria. Sin embargo, existen escasos datos sobre sus resultados en mujeres embarazadas. Presentamos el caso de una mujer embarazada que se sometió con éxito a un TMF para el tratamiento de una ICD recurrente.

The diagnosis of Clostridioides dfficile infection (CDI) in pregnant and peripartum women has increased. In this scenario, there are higher rates of treatment failure and a significant maternal morbidity and mortality. Fecal microbiota transplant (FMT) has become the gold standard for the treatment of recurrent and refractory CDI however, there are few data on its results in pregnant patients. This case showed that FMT could be a therapeutic strategy in pregnant women with recurrent CDI.

Trasplante de microbiota fecal por colonoscopía en paciente mayor de 65 años con infección recurrente de Clostridioides difficile: aún una estrategia subutilizada / Fecal microbiota transplantation in an older patient with Clostridioides difficile recurrent infection. Report of one case

Clostridioides difficile infection (CDI) is a major public health problem and responsible for significant morbidity and mortality. Eighty percent of CDIs occur in adults older than 65 years of age due to a decreased gastrointestinal microbial diversity, immunosenescence and frailty. Thus, the most reported risk factor for recurrent CDI is older age since nearly 60% of cases occur in individuals aged ≥ 65 years. Fecal microbiota transplantation (FMT) is a highly cost-effective alternative to antibiotic treatment for patients with recurrent CDI. We report a 75-year-old male with recurrent CDI, who received a FMT after several unsuccessful antimicrobial treatments. He had a satisfactory evolution after the procedure and remained without diarrhea during the ensuing five months.

Intestinal inflammation and the microbiota: Beyond diversity.

The recent manuscript entitled "Relationship between clinical features and intestinal microbiota in Chinese patients with ulcerative colitis" reported a difference in the intestinal microbiota of patients with ulcerative colitis according to the severity of the colitis. The influence of the intestinal microbiota on the development and progress of gastrointestinal disorders is well established. Besides the diversity in the microbiome, the presence of virulence factors and toxins by commensal bacteria may affect an extensive variety of cellular processes, contributing to the induction of a proinflammatory environment.

Immunological mechanisms of fecal microbiota transplantation in recurrent Clostridioides difficile infection.

Fecal microbiota transplantation (FMT) is a successful method for treating recurrent Clostridioides difficile (C. difficile) infection (rCDI) with around 90% efficacy. Due to the relative simplicity of this approach, it is being widely used and currently, thousands of patients have been treated with FMT worldwide. Nonetheless, the mechanisms underlying its effects are just beginning to be understood. Data indicate that FMT effectiveness is due to a combination of microbiological direct mechanisms against C. difficile, but also through indirect mechanisms including the production of microbiota-derived metabolites as secondary bile acids and short chain fatty acids. Moreover, the modulation of the strong inflammatory response triggered by C. difficile after FMT seems to rely on a pivotal role of regulatory T cells, which would be responsible for the reduction of several cells and soluble inflammatory mediators, ensuing normalization of the intestinal mucosal immune system. In this minireview, we analyze recent advances in these immunological aspects associated with the efficacy of FMT.

Fecal Microbiota Transplantation During Lactation Programs the Metabolism of Adult Wistar Rats in a Sex-specific Way.

BACKGROUND: The intestinal microbiota is involved in many physiological processes. However, the effects of microbiota in metabolic programming still unknow. We evaluated whether the transplantation of fecal microbiota during early life can program health or disease during adulthood in a model of lean and obese male and female Wistar rats. METHODS: Parental obesity were induced using a small litter (SL, 3 pups/dam) model. At 90 d old, normal litter (NL, 9 pups/dam) and SL males and females (parents) from different litters were mated: NL male vs. NL female; SL male vs. SL female. After birth, male and female offspring rats were also standardized in normal litters or small litters . From the 10th until 25th d of life, the NL and SL male and female offspring received via gavage of a solution containing the diluted feces of the opposite dam (fecal microbiota, M) or saline solution (S). At 90 d of age, biometric and biochemical parameters were assessed. RESULTS: NLM male rats transplanted with obese microbiota showed increased body weight, and fat pad deposition, hyperinsulinemia, glucose intolerance and dyslipidemia. SLM male rats transplanted with lean microbiota had decreased retroperitoneal and mesenteric fat, triglycerides and VLDL levels and improvement of glucose tolerance. Despite SLM female rats showed higher visceral fat, microbiota transplantation in female rats caused no changes in these parameters compared with control groups. CONCLUSION: Fecal microbiota transplantation during lactation induces long-term effects on the metabolism of male Wistar rats. However, female rats were resistant to metabolic alterations caused by the treatment.

Lipids from gut microbiota: pursuing a personalized treatment.

The discovery of microbiome metabolites has enlivened the field of fecal transplantation for therapeutic purposes. However, the transfer of pathogenic living organisms was recently observed to limit its therapeutic potential by increasing the risk of infection. Lipids produced by gut microbiota enter the circulation and control many phenotypic changes associated with microbiota composition. Fecal lipids significantly impact the regulation of several cell signaling pathways, including inflammation. Focusing on these molecules, we review how bioactive gut microbiota-associated lipids affect cellular functioning and clinical outcome. Here, we interrogate whether the gut microbiota can be considered a cutting-edge biotechnological tool for rapid metabolic engineering of meaningful lipids to offer a novel personalized therapy.