Modulating the Gut Micro-Environment in the Treatment of Intestinal Parasites

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 relmβ 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.

The effect of probiotic-fortified kefir on cardiovascular risk factors in elderly population: a double-blind, randomized, placebo-controlled clinical trial

INTRODUCTION

The outbreak of cardiovascular disease (CVD) augments with age. Gut dysbiosis can worsen or initiate systemic disorders such as metabolic diseases and CVDs. Therefore, this research aimed to assess the effect of kefir fortified with Lactobacillus helveticus R0052 and Bifidobacterium longum R017 on CVD risk factors in the elderly population. The subjects of this study were selected from the Motahari Clinic in Shiraz, Iran.

METHOD

This study was a double-blind, randomized, and controlled clinical trial that was conducted on 67 elderly people who were randomly divided into two groups: the fortified kefir group (n = 32), which received one bottle of fortified kefir (240 cc), and the placebo group (n = 35), which received one bottle of regular kefir for eight weeks. To analyze the data, SPSS software was applied.

RESULTS

After eight weeks, significant differences were seen in atherogenic and Castell's risk index I between the fortified and regular groups (p = 0.048 and p = 0.048, respectively). No significant differences were found in Castelli's risk index II, high-density lipoprotein cholesterol (HDL-C), total cholesterol, triglycerides (TG), non-HDL-C, TG-cholesterol index, and fasting blood sugar by comparing the two groups.

CONCLUSION

Our investigation demonstrated that fortified kefir with probiotics did not significantly affect lipid profiles. Still, it could significantly affect some indices, including Castelli's risk index I and atherogenic index. More studies are required to confirm the findings and mechanisms of probiotics' effect on CVD risk factors.

TRIAL NUMBER

The present registered at the Iranian Registry of Clinical Trials (IRCT20130227012628N3) at 2023-02-21.

Blastocystis: A Mysterious Member of the Gut Microbiome

Blastocystis is the most common gastrointestinal protist found in humans and animals. Although the clinical significance of Blastocystis remains unclear, the organism is increasingly being viewed as a commensal member of the gut microbiome. However, its impact on the microbiome is still being debated. It is unclear whether Blastocystis promotes a healthy gut and microbiome directly or whether it is more likely to colonize and persist in a healthy gut environment. In healthy people, Blastocystis is frequently associated with increased bacterial diversity and significant differences in the gut microbiome. Based on current knowledge, it is not possible to determine whether differences in the gut microbiome are the cause or result of Blastocystis colonization. Although it is possible that some aspects of this eukaryote's role in the intestinal microbiome remain unknown and that its effects vary, possibly due to subtype and intra-subtype variations and immune modulation, more research is needed to characterize these mechanisms in greater detail. This review covers recent findings on the effects of Blastocystis in the gut microbiome and immune modulation, its impact on the microbiome in autoimmune diseases, whether Blastocystis has a role like bacteria in the gut-brain axis, and its relationship with probiotics.

Taeniasis impacts human gut microbiome composition and function

Human taeniasis, caused by Taenia tapeworms, is a global parasitic disease with significant implications for public health and food safety. These tapeworms can grow to considerable sizes and potentially impact the microecology of the host gut. Despite their importance, the effects of Taenia infection on host gut microbiota haven't been thoroughly investigated. In this study, we conducted a cross-sectional analysis of the gut microbiome in patients infected with Taenia asiatica (n = 87) compared to healthy controls (n = 79) in the Dali cohort, China. We also performed a longitudinal assessment of microbial changes following deworming in a subset of patients (n = 24). Our findings reveal a significant shift in gut microbial composition, characterized by increased alpha-diversity and an enrichment of Prevotella-driven enterotypes in infected patients compared to healthy controls. The stability of these microbial features post-deworming varied widely among individuals and was lower in those with lower initial alpha diversity and Prevotella-enterotype before deworming. We observed a significant depletion of Bifidobacterium species in infected individuals, regardless of enterotypes, and these prebiotics did not recover post-deworming. Metabolic network analysis and in vitro experiments suggest that the reduction of Bifidobacterium was linked to metabolic competition for ecological niches or nutrients, particularly stachyose, from other microbes rather than the parasitism itself. Furthermore, our machine learning analysis demonstrated that taxa associated with Bifidobacterium in stachyose metabolism could robustly predict infection but could not predict deworming. This study highlights the substantial impact of taeniasis on the human gut microbiome and overall gut health.

Bioactive Antimicrobial Peptides from Food Proteins: Perspectives and Challenges for Controlling Foodborne Pathogens

Bioactive peptides (BAPs) derived from food proteins have been extensively studied for their health benefits, majorly exploring their potential use as nutraceuticals and functional food components. These peptides possess a range of beneficial properties, including antihypertensive, antioxidant, immunomodulatory, and antibacterial activities, and are naturally present within dietary protein sequences. To release food-grade antimicrobial peptides (AMPs), enzymatic protein hydrolysis or microbial fermentation, such as with lactic acid bacteria (LAB), can be employed. The activity of AMPs is influenced by various structural characteristics, including the amino acid composition, three-dimensional conformation, liquid charge, putative domains, and resulting hydrophobicity. This review discusses the synthesis of BAPs and AMPs, their potential for controlling foodborne pathogens, their mechanisms of action, and the challenges and prospects faced by the food industry. BAPs can regulate gut microbiota by promoting the growth of beneficial bacteria or by directly inhibiting pathogenic microorganisms. LAB-promoted hydrolysis of dietary proteins occurs naturally in both the matrix and the gastrointestinal tract. However, several obstacles must be overcome before BAPs can replace antimicrobials in food production. These include the high manufacturing costs of current technologies, limited in vivo and matrix data, and the difficulties associated with standardization and commercial-scale production.

The regulatory function of Blastocystis spp. on the immune inflammatory response in the gut microbiome

Blastocystis spp. is a unicellular organism that resides in digestive tract of various vertebrates, with a worldwide distribution and a variable prevalence. For many years, Blastocystis spp. was considered a cyst of a flagellate, a fungus, or a saprophyte yeast of the digestive tract; in 1996, it is placed in the group of stramenopiles (heterokonts). Since its new classification, many questions have arisen around this protist about its role as a pathogen or non-pathogen organism. Recent evidence indicates that Blastocystis spp. participates in the immune inflammatory response in the intestinal microbiome generating an anti-inflammatory response, showing a lower concentration of fecal inflammatory markers in infected human hosts. Here, we review recent findings on the regulatory function of Blastocystis spp. in the immune inflammatory response to comprehend the purpose of Blastocystis spp. in health and disease, defining if Blastocystis spp. is really a pathogen, a commensal or even a mutualist in the human gut microbiome.

Utilizing Probiotics for the Prevention and Treatment of Gastrointestinal Diseases

Probiotics are heavily advertised to promote a healthy gastrointestinal tract and boost the immune system. This review article summarizes the history and diversity of probiotics, outlines conventional in vitro assays and in vivo models, assesses the pharmacologic effects of probiotic and pharmaceutical co-administration, and the broad impact of clinical probiotic utilization for gastrointestinal disease indications.

Bile Salt Hydrolases: At the Crossroads of Microbiota and Human Health

The gut microbiota has been increasingly linked to metabolic health and disease over the last few decades. Several factors have been suggested to be involved in lipid metabolism and metabolic responses. One mediator that has gained great interest as a clinically important enzyme is bile salt hydrolase (BSH). BSH enzymes are widely distributed in human gastrointestinal microbial communities and are believed to play key roles in both microbial and host physiology. In this review, we discuss the current evidence related to the role of BSHs in health and provide useful insights that may pave the way for new therapeutic targets in human diseases.

Human intestinal models to study interactions between intestine and microbes

Implementations of suitable in vitro cell culture systems of the human intestine have been essential tools in the study of the interaction among organs, commensal microbiota, pathogens and parasites. Due to the great complexity exhibited by the intestinal tissue, researchers have been developing in vitro/ex vivo systems to diminish the gap between conventional cell culture models and the human intestine. These models are able to reproduce different structures and functional aspects of the tissue. In the present review, information is recapitulated on the most used models, such as cell culture, intestinal organoids, scaffold-based three-dimensional models, and organ-on-a-chip and their use in studying the interaction between human intestine and microbes, and their advantages and limitations are also discussed.

Probiotic Bacteria can Modulate Murine Macrophage's Superoxide Production in Trichinella Spiralis Infection

The effect of probiotic strains (Enterococcus faecium EF55, E. faecium CCM7420, E. faecium CCM8558, E. durans ED26E/7, Lactobacillus fermentum CCM7421, L. plantarum 17L/1) on the production of superoxide anion (O₂^-) in peritoneal macrophages of Trichinella spiralis infected mice was examined. E. faecium EF55 and E. faecium CCM8558 strains increased the O₂^-production prior to parasitic infection,at the day7of application.A significant inhibition of the O₂^- production caused by T. spiralis infection on day 5 post infection (p.i.) was prevented by all examined strains. Lactobacilli stimulated metabolic activity of macrophages during intestinal and early muscular phase (from day 5 to 25 p.i.) of trichinellosis. Enterococci increased the O₂^- production in early intestinal phase (day 5 p.i.) and during the muscular phase of trichinellosis (days 25 and 32 p.i.). Respected increase in macrophage’s metabolic activity induced by probiotic treatment in the intestinal phase of trichinellosis augmented the host antiparasite defence (damage and killing of newborn larvae with reactive oxygen species from macrophages).

An examination of data from the American Gut Project reveals that the dominance of the genus Bifidobacterium is associated with the diversity and robustness of the gut microbiota

Bifidobacterium and Lactobacillus are beneficial for human health, and many strains of these two genera are widely used as probiotics. We used two large datasets published by the American Gut Project (AGP) and a gut metagenomic dataset (NBT) to analyze the relationship between these two genera and the community structure of the gut microbiota. The meta-analysis showed that Bifidobacterium, but not Lactobacillus, is among the dominant genera in the human gut microbiota. The relative abundance of Bifidobacterium was elevated when Lactobacillus was present. Moreover, these two genera showed a positive correlation with some butyrate producers among the dominant genera, and both were associated with alpha diversity, beta diversity, and the robustness of the gut microbiota. Additionally, samples harboring Bifidobacterium present but no Lactobacillus showed higher alpha diversity and were more robust than those only carrying Lactobacillus. Further comparisons with other genera validated the important role of Bifidobacterium in the gut microbiota robustness. Multivariate analysis of 11,744 samples from the AGP dataset suggested Bifidobacterium to be associated with demographic features, lifestyle, and disease. In summary, Bifidobacterium members, which are promoted by dairy and whole-grain consumption, are more important than Lactobacillus in maintaining the diversity and robustness of the gut microbiota.

Inflammatory Bowel Disease: A Potential Result from the Collusion between Gut Microbiota and Mucosal Immune System

Host health depends on the intestinal homeostasis between the innate/adaptive immune system and the microbiome. Numerous studies suggest that gut microbiota are constantly monitored by the host mucosal immune system, and any slight disturbance in the microbial communities may contribute to intestinal immune disruption and increased susceptibility to inflammatory bowel disease (IBD), a chronic relapsing inflammatory condition of the gastrointestinal tract. Therefore, maintaining intestinal immune homeostasis between microbiota composition and the mucosal immune system is an effective approach to prevent and control IBD. The overall theme of this review is to summarize the research concerning the pathogenesis of IBD, with particular focus on the factors of gut microbiota-mucosal immune interactions in IBD. This is a comprehensive and in-depth report of the crosstalk between gut microbiota and the mucosal immune system in IBD pathogenesis, which may provide insight into the further evaluation of the therapeutic strategies for IBD.

Lower prevalence of Blastocystis sp. infections in HIV positive compared to HIV negative adults in Ghana

Background

Sub-Saharan Africa is endemic for intestinal parasites and distinguished for the largest burden of HIV cases. Blastocystis sp. is one of the most common protists infecting humans but its role in human disease is still controversial. Aim of this study was to investigate the prevalence of Blastocystis sp. in HIV positive and negative adults in Ghana and its association with immune status and other risk factors.

Methods

122 HIV positive outpatients and 70 HIV negative blood donors from the Komfo Anokye Teaching Hospital in Kumasi, Ghana, were included in the present study. Demographic, clinical and laboratory data were collected and HIV positive patients distinguished for CD4+ T cell count <200 cells/μl (n = 54) and >200 cells/μl (n = 68). A Blastocystis’s phylogenetic analysis was performed to determine sample subtype (ST).

Results

The prevalence of Blastocystis sp. in adult HIV positive individuals was lower than in HIV negative persons (6.6% vs. 20.0%, p = 0.008) and Blastocystis sp. ST1 was the most prevalent strain. Within HIV positive participants, the prevalence of Blastocystis sp. was lower in those individuals with CD4+ T cell count <200 cells/μl than in patients with higher CD4+ T cell count (1.9% vs. 10.3%, p = 0.076). Multiple regression analysis revealed that Blastocystis sp. was inversely associated with an obese Body Mass Index (BMI) in HIV negative persons (p = 0.040). Presence of Blastocystis sp. was correlated with higher CD4+ T cell count in HIV positive participants (p = 0.049).

Conclusion

It is largely reported that people living with HIV (PLHIV) in Africa are affected from parasite infections and that co-infections may adversely impact on their immune status, accelerating progress to AIDS and worsening gastrointestinal manifestations. Differently, in this study Blastocystis sp. was associated with a better immune status jointly with a healthy body weight while it seems to be reduced with the progression of HIV infection. This data agree with recent suggestions that Blastocystis sp. can represent a component of the healthy gut microbiota.

Microbiota-Immune Interaction in the Pathogenesis of Gut-Derived Infection

Gut-derived infection is among the most common complications in patients who underwent severe trauma, serious burn, major surgery, hemorrhagic shock or severe acute pancreatitis (SAP). It could cause sepsis and multiple organ dysfunction syndrome (MODS), which are regarded as a leading cause of mortality in these cases. Gut-derived infection is commonly caused by pathological translocation of intestinal bacteria or endotoxins, resulting from the dysfunction of the gut barrier. In the last decades, the studies regarding to the pathogenesis of gut-derived infection mainly focused on the breakdown of intestinal epithelial tight junction and increased permeability. Limited information is available on the roles of intestinal microbial barrier in the development of gut-derived infection. Recently, advances of next-generation DNA sequencing techniques and its utilization has revolutionized the gut microecology, leading to novel views into the composition of the intestinal microbiota and its connections with multiple diseases. Here, we reviewed the recent progress in the research field of intestinal barrier disruption and gut-derived infection, mainly through the perspectives of the dysbiosis of intestinal microbiota and its interaction with intestinal mucosal immune cells. This review presents novel insights into how the gut microbiota collaborates with mucosal immune cells to involve the development of pathological bacterial translocation. The data might have important implication to better understand the mechanism underlying pathological bacterial translocation, contributing us to develop new strategies for prevention and treatment of gut-derived sepsis.

Interactions Between Parasites and the Bacterial Microbiota of Chickens

Except for the important role coccidia have as predisposing factors of necrotic enteritis, the role parasites play in the dynamics of a healthy microbiota of chickens is not well explored. This review describes the interactions of relevant intestinal parasites of chickens with bacteria. Infection with Eimeria spp. favor the growth of Clostridium perfringens and suppress the growth of many other bacteria by increasing viscosity and passage time of the ingesta, and by causing lesions to the intestinal mucosa that improve the availability of nutrients for C. perfringens. Conversely, there are indications that bacteria influence the course of disease after infections with Eimeria spp. Not much is known about intestinal cryptosporidiosis in chickens, but results in mice show that the intestinal microbiota induces some resistance against infection with Cryptosporidium parvum and that the innate immune response triggered by infections with cryptosporidia might have an effect on other intestinal microbes. Histomonas meleagridis depend on bacteria in vitro, and in vivo it will cause lesions in chickens only in the presence of bacteria. Blastocystis spp. are very common in chickens, but there is no information about interactions with bacteria. In humans, there is evidence of the correlation of the detection of Blastocystis and changes in the intestinal microbiota. There are indications of interactions between Ascaridia galli and various bacteria in chickens and Ascaridia spp. of mammals are known to produce various types of antimicrobial molecules. However, often the underlying mechanisms of these interactions between parasites and bacteria remain unknown and only correlations but not causation can be established.

Treatment-refractory giardiasis: challenges and solutions

Giardia is the commonest parasitic diarrheal pathogen affecting humans and a frequent cause of waterborne/foodborne parasitic diseases worldwide. Prevalence of giardiasis is higher in children, living in poor, low hygiene settings in developing countries, and in travelers returning from highly endemic areas. The clinical picture of giardiasis is heterogeneous, with high variability in severity of clinical disease. It can become chronic or be followed by post-infectious sequelae. An alarming increase in cases refractory to the conventional treatment with nitroimidazoles (ie, metronidazole) has been reported in low prevalence settings, such as European Union countries, especially in patients returning from Asia. In view of its relevance, we aim in this review to recapitulate present clinical knowledge about Giardia, with a special focus on the challenge of treatment-refractory giardiasis. We propose a working definition of clinically drug-resistant giardiasis, summarize knowledge regarding resistance mechanisms, and discuss its clinical management according to research-based evidence and medical practice. Advances in development and identification of novel drugs and potential non-pharmacological alternatives are also reviewed with the overall aim to define knowledge gaps and suggest future directions for research.

Exclusive enteral nutrition protects against inflammatory bowel disease by inhibiting NF‑κB activation through regulation of the p38/MSK1 pathway

Although enteral nutrition therapy for inflammatory bowel disease has been confirmed to be an effective treatment method, the exact mechanism responsible for the effects of enteral nutrition remains unclear. The aim of the present study was to investigate the protective effect of exclusive enteral nutrition (EEN) against colitis, and to elucidate the potential mechanisms by inhibiting p65 activation via regulating the p38/mitogen‑ and stress‑activated protein kinase‑1 (MSK1) pathway. Experiments were performed by establishing dextran sulfate sodium (DSS)‑mice colitis and picrylsulfonic acid solution (TNBS)‑induced rat colitis, and the results demonstrated that EEN treatment attenuated body weight loss, colon length shortening and colonic pathological damage caused by colitis. EEN also inhibited inflammatory cells infiltration and decreased myeloperoxidase and inducible nitric oxide synthase activities. Furthermore, EEN significantly reduced the production of pro‑inflammatory mediators in serum and the colon. Mechanically, EEN suppressed activation of p65 by inhibiting the p38/MSK1 pathway. In conclusion, the present study demonstrated that EEN attenuated DSS‑ and TNBS‑induced colitis by inhibiting p65 activation via regulating the p38/MSK1 pathway, thus suggesting that EEN is effective in the treatment of colitis.

Human Intestinal Microbiota: Interaction Between Parasites and the Host Immune Response

The human gut is a highly complex ecosystem with an extensive microbial community, and the influence of the intestinal microbiota reaches the entire host organism. For example, the microbiome regulates fat storage, stimulates or renews epithelial cells, and influences the development and maturation of the brain and the immune system. Intestinal microbes can protect against infection by pathogenic bacteria, viruses, fungi and parasites. Hence, the maintenance of homeostasis between the gut microbiota and the rest of the body is crucial for health, with dysbiosis affecting disease. This review focuses on intestinal protozoa, especially those still representing a public health problem in Mexico, and their interactions with the microbiome and the host. The decrease in prevalence of intestinal helminthes in humans left a vacant ecological niche that was quickly occupied by protozoa. Although the mechanisms governing the interaction between intestinal microbiota and protozoa are poorly understood, it is known that the composition of the intestinal bacterial populations modulates the progression of protozoan infection and the outcome of parasitic disease. Most reports on the complex interactions between intestinal bacteria, protozoa and the immune system emphasize the protective role of the microbiota against protozoan infection. Insights into such protection may facilitate the manipulation of microbiota components to prevent and treat intestinal protozoan infections. Here we discuss recent findings about the immunoregulatory effect of intestinal microbiota with regards to intestinal colonization by protozoa, focusing on infections by Entamoeba histolytica, Blastocystis spp, Giardia duodenalis, Toxoplasma gondii and Cryptosporidium parvum. The possible consequences of the microbiota on parasitic, allergic and autoimmune disorders are also considered.