Effects of Diet-Modulated Autologous Fecal Microbiota Transplantation on Weight Regain

The effects of the Green-Mediterranean diet on cardiometabolic health are linked to gut microbiome modifications: a randomized controlled trial

BACKGROUND

Previous studies have linked the Mediterranean diet (MED) with improved cardiometabolic health, showing preliminary evidence for a mediating role of the gut microbiome. We recently suggested the Green-Mediterranean (Green-MED) diet as an improved version of the healthy MED diet, with increased consumption of plant-based foods and reduced meat intake. Here, we investigated the effects of MED interventions on the gut microbiota and cardiometabolic markers, and the interplay between the two, during the initial weight loss phase of the DIRECT-PLUS trial.

METHODS

In the DIRECT-PLUS study, 294 participants with abdominal obesity/dyslipidemia were prospectively randomized to one of three intervention groups: healthy dietary guidelines (standard science-based nutritional counseling), MED, and Green-MED. Both isocaloric MED and Green-MED groups were supplemented with 28g/day walnuts. The Green-MED group was further provided with daily polyphenol-rich green tea and Mankai aquatic plant (new plant introduced to a western population). Gut microbiota was profiled by 16S rRNA for all stool samples and shotgun sequencing for a select subset of samples.

RESULTS

Both MED diets induced substantial changes in the community structure of the gut microbiome, with the Green-MED diet leading to more prominent compositional changes, largely driven by the low abundant, "non-core," microorganisms. The Green-MED diet was associated with specific microbial changes, including enrichments in the genus Prevotella and enzymatic functions involved in branched-chain amino acid degradation, and reductions in the genus Bifidobacterium and enzymatic functions responsible for branched-chain amino acid biosynthesis. The MED and Green-MED diets were also associated with stepwise beneficial changes in body weight and cardiometabolic biomarkers, concomitantly with the increased plant intake and reduced meat intake. Furthermore, while the level of adherence to the Green-MED diet and its specific green dietary components was associated with the magnitude of changes in microbiome composition, changes in gut microbial features appeared to mediate the association between adherence to the Green-MED and body weight and cardiometabolic risk reduction.

CONCLUSIONS

Our findings support a mediating role of the gut microbiome in the beneficial effects of the Green-MED diet enriched with Mankai and green tea on cardiometabolic risk factors.

TRIAL REGISTRATION

The study was registered on ClinicalTrial.gov ( NCT03020186 ) on January 13, 2017.

Personal diet-microbiota interactions and weight loss

The aim of this review is to provide an overview of how person-specific interactions between diet and the gut microbiota could play a role in affecting diet-induced weight loss responses. The highly person-specific gut microbiota, which is shaped by our diet, secretes digestive enzymes and molecules that affect digestion in the colon. Therefore, weight loss responses could in part depend on personal colonic fermentation responses, which affect energy extraction of food and production of microbial metabolites, such as short-chain fatty acids (SCFAs), which exert various effects on host metabolism. Colonic fermentation is the net result of the complex interplay between availability of dietary substrates, the functional capacity of the gut microbiome and environmental (abiotic) factors in the gut such as pH and transit time. While animal studies have demonstrated that the gut microbiota can causally affect obesity, causal and mechanistic evidence from human studies is still largely lacking. However, recent human studies have proposed that the baseline gut microbiota composition may predict diet-induced weight loss-responses. In particular, individuals characterised by high relative abundance of Prevotella have been found to lose more weight on diets rich in dietary fibre compared to individuals with low Prevotella abundance. Although harnessing of personal diet-microbiota interactions holds promise for more personalised nutrition and obesity management strategies to improve human health, there is currently insufficient evidence to unequivocally link the gut microbiota and weight loss in human subjects. To move the field forward, a greater understanding of the mechanistic underpinnings of personal diet-microbiota interactions is needed.

Alterations in the Gut Microbiota and Their Metabolites in Colorectal Cancer: Recent Progress and Future Prospects

Colorectal cancer (CRC) is a leading cause of cancer morbidity and mortality worldwide. The etiology and pathogenesis of CRC remain unclear. A growing body of evidence suggests dysbiosis of gut bacteria can contribute to the occurrence and development of CRC by generating harmful metabolites and changing host physiological processes. Metabolomics, a systems biology method, will systematically study the changes in metabolites in the physiological processes of the body, eventually playing a significant role in the detection of metabolic biomarkers and improving disease diagnosis and treatment. Metabolomics, in particular, has been highly beneficial in tracking microbially derived metabolites, which has substantially advanced our comprehension of host-microbiota metabolic interactions in CRC. This paper has briefly compiled recent research progress of the alterations of intestinal flora and its metabolites associated with CRC and the application of association analysis of metabolomics and gut microbiome in the diagnosis, prevention, and treatment of CRC; furthermore, we discuss the prospects for the problems and development direction of this association analysis in the study of CRC. Gut microbiota and their metabolites influence the progression and causation of CRC, and the association analysis of metabolomics and gut microbiome will provide novel strategies for the prevention, diagnosis, and therapy of CRC.

An update on fecal microbiota transplantation for the treatment of gastrointestinal diseases

Our understanding of the microbiome and its implications for human health and disease continues to develop. Fecal microbiota transplantation (FMT) is now an established treatment for recurrent Clostridioides difficile infection. There is also increasing evidence for the efficacy of FMT in inducing remission for mild-moderate ulcerative colitis. However, for other indications, data for FMT are limited, with randomized controlled trials rare, typically small and often conflicting. Studies are continuing to explore the role of FMT for many other conditions, including Crohn's disease, functional gut disorders, metabolic syndrome, modulating responses to chemotherapy, eradication of multidrug resistant organisms, and the gut-brain axis. In light of safety, logistical, and regulatory challenges, there is a move to standardized products including narrow spectrum consortia. However, the mechanisms underpinning FMT remain incompletely understood, including the role of non-bacterial components, which may limit success of novel microbial approaches.

Health improvements of type 2 diabetic patients through diet and diet plus fecal microbiota transplantation

Type 2 diabetes (T2D) is a major public health problem, and gut microbiota dysbiosis has been implicated in the emergence of T2D in humans. Dietary interventions can indirectly influence the health status of patients with type 2 diabetes through their modulatory effects on the intestinal microbiota. In recent years, fecal microbiota transplantation is becoming familiar as a new medical treatment that can rapidly improve intestinal health. We conducted a 90-day controlled open-label trial to evaluate the health improvement ability of a specially designed diet, and the diet combined with fecal microbiota transplantation (FMT). According to our study, both diet and diet plus FMT treatments showed great potential in controlling blood glucose and blood pressure levels. Sequencing the V4 region of 16S rRNA gene on the Illumina MiniSeq platform revealed a shift of intestinal microbial community in T2D patients, and the changes were also observed in response to the treatments. FMT changed the gut microbiota more quickly than diet. Beneficial bacterium, such as Bifidobacterium, increased along the study and was negatively correlated with blood glucose, blood pressure, blood lipid and BMI. Sulfate-reducing bacteria (SRB), Bilophila and Desulfovibrio, decreased significantly after treatment, showed a positive correlation with blood glucose indices. Thus, the specially designed diet is beneficial to improve blood glucose control in diabetic patients, it also showed the potential to reverse dyslipidemia and dysarteriotony.

SLC3A2 inhibits ferroptosis in laryngeal carcinoma via mTOR pathway

Objective

This study aimed to explore the mRNA and protein expression of SLC3A2 in laryngeal carcinoma cells and tissues, and functional regulatory mechanism of SLC3A2 in cell ferroptosis of laryngeal carcinoma.

Methods

We chose the key gene-SLC3A2 of DEGs from TCGA by bioinformatics analysis, and then we constructed stable knockdown of SLC3A2 in laryngeal carcinoma cells. MTT assay and clonogenic assay were used to determine cell viability and cell growth, respectively. The mRNA and protein expression were determined by RT-qPCR and western blotting, respectively. Xenograft tumor model was used to determine the role of SLC3A2 in tumor growth.

Results

The results of limma analysis recovered that 92 genes were involved in both upregulated DEGs and high risk of poor prognosis, whereas 36 genes were involved in both downregulated DEGs and low risk of poor prognosis. Pathway enrichment analysis indicated that mTOR signaling pathway and ferroptosis exerted a role in regulating these intersection genes. Moreover, SLC3A2 is a key gene in ferroptosis in laryngeal carcinoma. SLC3A2 is highly expressed in laryngeal carcinoma tissues and cells. Patients with high SLC3A2 expression exerted poor survival. SLC3A2 deficiency inhibited cell proliferation and foci formation. Furthermore, knockdown of SLC3A2 expression induced the efficacy of ferroptosis and suppressed ferroptosis related proteins expression. Mechanically, SLC3A2 deficiency facilitated ferroptosis through upregulating the expression of mTOR and P70S6K, whereas inhibited p-mTOR and p-P70S6K expression in laryngeal carcinoma cells. SLC3A2 deficiency inhibited tumorigenesis in nude mice.

Conclusion

Our study suggests that SLC3A2 negatively regulates ferroptosis through mTOR pathway in laryngeal carcinoma.

Current Status and Future Therapeutic Options for Fecal Microbiota Transplantation

The intestinal microbiota plays an important role in maintaining human health, and its alteration is now associated with the development of various gastrointestinal (ulcerative colitis, irritable bowel syndrome, constipation, etc.) and extraintestinal diseases, such as cancer, metabolic syndrome, neuropsychiatric diseases. In this context, it is not surprising that gut microbiota modification methods may constitute a therapy whose potential has not yet been fully investigated. In this regard, the most interesting method is thought to be fecal microbiota transplantation, which consists of the simultaneous replacement of the intestinal microbiota of a sick recipient with fecal material from a healthy donor. This review summarizes the most interesting findings on the application of fecal microbiota transplantation in gastrointestinal and extraintestinal pathologies.

Fecal microbiota transplantation reverses insulin resistance in type 2 diabetes: A randomized, controlled, prospective study

OBJECTIVES

Recent studies have shown that fecal microbiota transplantation (FMT) improved the metabolic profiles of patients with type 2 diabetes mellitus (T2DM), yet the effectiveness in reversing insulin resistance and increasing metformin sensitivity in T2DM patients have not been reported. In this study, we evaluated the improvements of T2DM patients and their gut microbiota by FMT alone and FMT plus metformin.

METHODS

A total of 31 patients with newly diagnosed T2DM were randomized to intervention by metformin, FMT, or FMT plus metformin in the study. Patients were followed up at baseline and week 4 after treatment. Blood and stool samples were collected and subject to analyze clinical parameters and microbial communities by metagenomic sequencing, respectively.

RESULTS

FMT alone and FMT plus metformin significantly improved the clinical indicators HOMA-IR and BMI in T2DM, besides fasting blood glucose, postprandial blood glucose, and hemoglobin A1c that were also controlled by metformin. Donor microbiota effectively colonized in T2DM with slightly higher colonization ration in FMT than FMT plus metformin within 4 weeks, resulting in increased microbial diversity and community changes from baseline after treatment. A total of 227 species and 441 species were significantly alerted after FMT and FMT plus metformin, respectively. FMT were significantly associated with the clinical parameters. Among them, Chlorobium phaeovibrioides, Bifidibacterium adolescentis and Synechococcus sp.WH8103 were potential due to their significantly negative correlations with HOMA-IR.

CONCLUSIONS

FMT with or without metformin significantly improve insulin resistance and body mass index and gut microbial communities of T2DM patients by colonization of donor-derived microbiota.

Nutrition and Microbiome

The prevalence of overweight and obesity has reached epidemic proportions globally over the past few decades. The search for new management approaches continues and among them, targeting the gut microbiota can be envisioned. To date, numerous data showed the involvement of the gut microbes in the regulation and control of host metabolism. There are also increasing evidences highlighting the interactions between environmental factors, intrinsic factors, gut microbiota, and metabolic diseases. Diet emerges as the most relevant factor influencing the gut microbiome. Eating habits, as well as short-term consumption of specific diets, alter the gut microbiota composition. Moreover, nutritional disorders are associated with changes of the gut microbiota composition and/or function, as shown in obesity or type 2 diabetic patients versus healthy lean subjects. Targeting the gut microbiota for improving metabolic health appears as a new approach to manage obesity and cardio-metabolic risk. In this review, we have detailed the results of human interventions targeting the gut microbiome by prebiotic supplementation, prebiotics being defined as "substrates that are selectively utilized by the host microorganisms conferring a health benefit." If the potential benefit of this approach is obvious in preclinical models, the efficacy of prebiotics in humans is less reproducible. The inter-individual variability of response to dietary intervention can be dependent on the gut microbiota and we summarized the basal gut microbiota characteristics driving the metabolic response to dieting, prebiotic and dietary fiber intervention in the context of obesity and related metabolic diseases.

Washed microbiota transplantation improves patients with high blood glucose in South China

BACKGROUND AND AIMS

Although fecal microbiota transplantation (FMT) from healthy donors has been shown to have hypoglycemic effects in animal models of diabetes, its clinical impact in patients with abnormal blood glucose metabolism is unclear, especially in southern Chinese populations. The aim of this study was to investigate the feasibility and efficacy of washed microbiota transplantation (WMT) in the treatment of abnormal blood glucose metabolism in a population in southern China.

METHODS

The clinical data of patients with different indications who received 1-3 treatments of WMT were retrospectively collected. The changes of blood glucose, blood lipids, blood pressure, liver function and blood routine before and after WMT were compared, such as fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), systolic blood pressure (SBP), white blood cells (WBC), lymphocytes (LY) and platelets (PLT), etc.

RESULTS

A total of 195 patients were included in the First Affiliated Hospital of Guangdong Pharmaceutical University, including 20 patients with high blood glucose and 175 patients with normal blood glucose. WMT has a significant effect in reducing short term blood glucose level (FBG) in patients with high blood glucose (p < 0.05). The fasting blood glucose (FBG) of 72.22% of patients with high blood glucose decreased to normal in a short term (about 1 month) (p < 0.001); In the medium term (about 2 months), there was a significant hypolipidemic (TG) (p = 0.043) effect, long term (about 6 months) significant blood pressure lowering (SBP, p = 0.048) effect. Overall, WMT significantly reduced the risk of high risk classes of Atherosclerotic Cardiovascular Disease (ASCVD) in the short term (p = 0.029) and medium term (p = 0.050).

CONCLUSION

WMT can significantly improve blood glucose in patients with high blood glucose, and there is no long-term elevated risk of blood glucose and ASCVD. FBG levels were significantly reduced in both the short and medium term in patients with high blood glucose treated with WMT. Therefore, the regulation of gut microbiota by WMT may provide a new clinical approach for the treatment of abnormal blood glucose metabolism.

Effect of green-Mediterranean diet on intrahepatic fat: the DIRECT PLUS randomised controlled trial

OBJECTIVE

To examine the effectiveness of green-Mediterranean (MED) diet, further restricted in red/processed meat, and enriched with green plants and polyphenols on non-alcoholic fatty liver disease (NAFLD), reflected by intrahepatic fat (IHF) loss.

DESIGN

For the DIRECT-PLUS 18-month randomized clinical trial, we assigned 294 participants with abdominal obesity/dyslipidaemia into healthy dietary guidelines (HDG), MED and green-MED weight-loss diet groups, all accompanied by physical activity. Both isocaloric MED groups consumed 28 g/day walnuts (+440 mg/day polyphenols provided). The green-MED group further consumed green tea (3-4 cups/day) and Mankai (a Wolffia globosa aquatic plant strain; 100 g/day frozen cubes) green shake (+1240 mg/day total polyphenols provided). IHF% 18-month changes were quantified continuously by proton magnetic resonance spectroscopy (MRS).

RESULTS

Participants (age=51 years; 88% men; body mass index=31.3 kg/m²; median IHF%=6.6%; mean=10.2%; 62% with NAFLD) had 89.8% 18-month retention-rate, and 78% had eligible follow-up MRS. Overall, NAFLD prevalence declined to: 54.8% (HDG), 47.9% (MED) and 31.5% (green-MED), p=0.012 between groups. Despite similar moderate weight-loss in both MED groups, green-MED group achieved almost double IHF% loss (-38.9% proportionally), as compared with MED (-19.6% proportionally; p=0.035 weight loss adjusted) and HDG (-12.2% proportionally; p<0.001). After 18 months, both MED groups had significantly higher total plasma polyphenol levels versus HDG, with higher detection of Naringenin and 2-5-dihydroxybenzoic-acid in green-MED. Greater IHF% loss was independently associated with increased Mankai and walnuts intake, decreased red/processed meat consumption, improved serum folate and adipokines/lipids biomarkers, changes in microbiome composition (beta-diversity) and specific bacteria (p<0.05 for all).

CONCLUSION

The new suggested strategy of green-Mediterranean diet, amplified with green plant-based proteins/polyphenols as Mankai, green tea, and walnuts, and restricted in red/processed meat can double IHF loss than other healthy nutritional strategies and reduce NAFLD in half.

TRIAL REGISTRATION NUMBER

NCT03020186.

Dietary Management for Faecal Microbiota Transplant: An International Survey of Clinical and Research Practice, Knowledge and Attitudes

Faecal microbiota transplantation (FMT) involves homogenisation and infusion of stool from a healthy, highly screened individual into the bowel of an unwell recipient. Dietary intake is an important modulator of the gut microbiota. Currently there are no clinical practice recommendations available to provide patients or stool donors with dietary advice for FMT. This study aimed to conduct an international survey to examine health professionals and researchers' attitudes, knowledge and current practice recommendations for diet in patients undergoing FMT. An online, cross-sectional, international survey comprising of health professionals and researchers managing patients undergoing treatment with FMT was conducted between July-October 2020. Purposeful and snowball sampling techniques were employed to identify eligible participants who were sent an email invitation and two email reminders with a link to participate in the electronic survey. The survey comprised 21 questions covering demographics, current practice, beliefs and future directions regarding FMT and diet. Closed responses were calculated as proportions of total responses. Open-ended responses were systematically categorised. Common themes were identified from recurring categories. Fifty-eight (M 60%) participants from 14 countries completed the survey. Participants were gastroenterologists (55%), with 1-5 years' experience working in FMT (48%) and treating up to ten patients with FMT per month (74%). Participants agreed that diet was an important consideration for FMT recipients and stool donors (both 71%), and that it would affect the outcomes of FMT. However, they did not feel confident in providing dietary advice to patients, nor that there was sufficient evidence to provide dietary advice and this was reflected in their practice. Future research must collect information on the dietary intake of patients and donors to better understand the relationship between diet and FMT outcomes. In clinical practice, promotion of healthy eating guidelines aligns with current practice and literature.

Gut microbiota link dietary fiber intake and short-chain fatty acid metabolism with eating behavior

The gut microbiome has been speculated to modulate feeding behavior through multiple factors, including short-chain fatty acids (SCFA). Evidence on this relationship in humans is however lacking. We aimed to explore if specific bacterial genera relate to eating behavior, diet, and SCFA in adults. Moreover, we tested whether eating-related microbiota relate to treatment success in patients after Roux-en-Y gastric bypass (RYGB). Anthropometrics, dietary fiber intake, eating behavior, 16S-rRNA-derived microbiota, and fecal and serum SCFA were correlated in young overweight adults (n = 27 (9 F), 21-36 years, BMI 25-31 kg/m²). Correlated genera were compared in RYGB (n = 23 (16 F), 41-70 years, BMI 25-62 kg/m²) and control patients (n = 17 (11 F), 26-69 years, BMI 25-48 kg/m²). In young adults, 7 bacteria genera, i.e., Alistipes, Blautia, Clostridiales cluster XVIII, Gemmiger, Roseburia, Ruminococcus, and Streptococcus, correlated with healthier eating behavior, while 5 genera, i.e., Clostridiales cluster IV and XIVb, Collinsella, Fusicatenibacter, and Parabacteroides, correlated with unhealthier eating (all | r | > 0.4, FDR-corrected p < 0.05). Some of these genera including Parabacteroides related to fiber intake and SCFA, and to weight status and treatment response in overweight/obese patients. In this exploratory analysis, specific bacterial genera, particularly Parabacteroides, were associated with weight status and eating behavior in two small, independent and well-characterized cross-sectional samples. These preliminary findings suggest two groups of presumably beneficial and unfavorable genera that relate to eating behavior and weight status, and indicate that dietary fiber and SCFA metabolism may modify these relationships. Larger interventional studies are needed to distinguish correlation from causation.

Fecal microbiota transplantation and fiber supplementation, better together?

Fecal microbiota transplantation (FMT) is emerging as a tool to study the microbiome and as a potential treatment for several non-infectious diseases. Recently, Mocanu et al. showed that supplementing low fermentable fiber after FMT may improve insulin sensitivity in severely obese individuals.¹

Impact of Gut Microbiota and Microbiota-Related Metabolites on Hyperlipidemia

Hyperlipidemia, defined as the presence of excess fat or lipids in the blood, has been considered as a high-risk factor and key indicator of many metabolic diseases. The gut microbiota has been reported playing a vital role in regulating host lipid metabolism. The pathogenic role of gut microbiota in the development of hyperlipidemia has been revealed through fecal microbiota transplantation experiment to germ-free mice. The effector mechanism of microbiota-related metabolites such as bile acids, lipopolysaccharide, and short-chain fatty acids in the regulation of hyperlipidemia has been partially unveiled. Moreover, studies on gut-microbiota-targeted hyperlipidemia interventions, including the use of prebiotics, probiotics, fecal microbiota transplantation, and natural herbal medicines, also have shown their efficacy in the treatment of hyperlipidemia. In this review, we summarize the relationship between gut microbiota and hyperlipidemia, the impact of gut microbiota and microbiota-related metabolites on the development and progression of hyperlipidemia, and the potential therapeutic management of hyperlipidemia targeted at gut microbiota.

Recipient factors in faecal microbiota transplantation: one stool does not fit all

Faecal microbiota transplantation (FMT) is a promising therapy for chronic diseases associated with gut microbiota alterations. FMT cures 90% of recurrent Clostridioides difficile infections. However, in complex diseases, such as inflammatory bowel disease, irritable bowel syndrome and metabolic syndrome, its efficacy remains variable. It is accepted that donor selection and sample administration are key determinants of FMT success, yet little is known about the recipient factors that affect it. In this Perspective, we discuss the effects of recipient parameters, such as genetics, immunity, microbiota and lifestyle, on donor microbiota engraftment and clinical efficacy. Emerging evidence supports the possibility that controlling inflammation in the recipient intestine might facilitate engraftment by reducing host immune system pressure on the newly transferred microbiota. Deciphering FMT engraftment rules and developing novel therapeutic strategies are priorities to alleviate the burden of chronic diseases associated with an altered gut microbiota such as inflammatory bowel disease.

Effect of Fecal Microbiota Transplantation Combined With Mediterranean Diet on Insulin Sensitivity in Subjects With Metabolic Syndrome

Background

Recent studies demonstrate that a Mediterranean diet has beneficial metabolic effects in metabolic syndrome subjects. Since we have shown that fecal microbiota transplantation (FMT) from lean donors exerts beneficial effects on insulin sensitivity, in the present trial, we investigated the potential synergistic effects on insulin sensitivity of combining a Mediterranean diet with donor FMT in subjects with metabolic syndrome.

Design

Twenty-four male subjects with metabolic syndrome were put on a Mediterranean diet and after a 2-week run-in phase, the subjects were randomized to either lean donor (n = 12) or autologous (n = 12) FMT. Changes in the gut microbiota composition and bacterial strain engraftment after the 2-week dietary regimens and 6 weeks post-FMT were the primary endpoints. The secondary objectives were changes in glucose fluxes (both hepatic and peripheral insulin sensitivity), postprandial plasma incretin (GLP-1) levels, subcutaneous adipose tissue inflammation, and plasma metabolites.

Results

Consumption of the Mediterranean diet resulted in a reduction in body weight, HOMA-IR, and lipid levels. However, no large synergistic effects of combining the diet with lean donor FMT were seen on the gut microbiota diversity after 6 weeks. Although we did observe changes in specific bacterial species and plasma metabolites, no significant beneficial effects on glucose fluxes, postprandial incretins, or subcutaneous adipose tissue inflammation were detected.

Conclusions

In this small pilot randomized controlled trial, no synergistic beneficial metabolic effects of combining a Mediterranean diet with lean donor FMT on glucose metabolism were achieved. However, we observed engraftment of specific bacterial species. Future trials are warranted to test the combination of other microbial interventions and diets in metabolic syndrome.

Fecal microbiota transplantation in human metabolic diseases: From a murky past to a bright future?

Fecal microbiota transplantation (FMT) is gaining considerable traction as a therapeutic approach to influence the course of a plethora of chronic conditions, ranging from metabolic syndrome and malignancies to auto-immune and neurological diseases, and helped to establish the contribution of the gut microbiome to these conditions. Although FMT procedures have yielded important mechanistic insights, their use in clinical practice may be limited due to practical objections in the setting of metabolic diseases. While its applicability is established to treat recurrent Clostridiodes difficile, FMT is emerging in ulcerative colitis and various other diseases. A particularly new insight is that FMTs may not only alter insulin sensitivity but may also alter the course of type 1 diabetes by attenuating underlying auto-immunity. In this review, we will outline the major principles and pitfalls of FMT and where optimization of study design and the procedure itself will further advance the field of cardiometabolic medicine.

The Metabolomic-Gut-Clinical Axis of Mankai Plant-Derived Dietary Polyphenols

BACKGROUND

Polyphenols are secondary metabolites produced by plants to defend themselves from environmental stressors. We explored the effect of Wolffia globosa 'Mankai', a novel cultivated strain of a polyphenol-rich aquatic plant, on the metabolomic-gut clinical axis in vitro, in-vivo and in a clinical trial.

METHODS

We used mass-spectrometry-based metabolomics methods from three laboratories to detect Mankai phenolic metabolites and examined predicted functional pathways in a Mankai artificial-gut bioreactor. Plasma and urine polyphenols were assessed among the 294 DIRECT-PLUS 18-month trial participants, comparing the effect of a polyphenol-rich green-Mediterranean diet (+1240 mg/polyphenols/day, provided by Mankai, green tea and walnuts) to a walnuts-enriched (+440 mg/polyphenols/day) Mediterranean diet and a healthy controlled diet.

RESULTS

Approximately 200 different phenolic compounds were specifically detected in the Mankai plant. The Mankai-supplemented bioreactor artificial gut displayed a significantly higher relative-abundance of 16S-rRNA bacterial gene sequences encoding for enzymes involved in phenolic compound degradation. In humans, several Mankai-related plasma and urine polyphenols were differentially elevated in the green Mediterranean group compared with the other groups (p < 0.05) after six and 18 months of intervention (e.g., urine hydroxy-phenyl-acetic-acid and urolithin-A; plasma Naringenin and 2,5-diOH-benzoic-acid). Specific polyphenols, such as urolithin-A and 4-ethylphenol, were directly involved with clinical weight-related changes.

CONCLUSIONS

The Mankai new plant is rich in various unique potent polyphenols, potentially affecting the metabolomic-gut-clinical axis.

Treating the Metabolic Syndrome by Fecal Transplantation-Current Status

The intestinal microbiome (IM) is important for normal gastrointestinal (GI) and other organ systems' functioning. An alteration in the normal IM, dysbiosis, and changes in intestinal motility result in microorganisms' overgrowth and an alteration in intestinal permeability. The gut-brain axis is also of importance in the irritable bowel syndrome (IBS) and associated bowel overgrowth. Secondary to the epidemic of obesity, the metabolic syndrome has become a major health problem. Disturbances in the fecal microbiome are associated with the metabolic syndrome. Metabolic-associated fatty liver disease (MAFLD) is now the current terminology for non-alcoholic fatty liver disease. IM alteration by fecal transplantation is an approved treatment method for recurrent Clostridioides difficile infection. Initially performed by either duodenal infusion or colonoscopy, it is now easily performed by the administration of capsules containing stools. We discuss the intestinal microbiome-its composition, as well as the qualitative changes of microbiome composition leading to inflammation. In addition, we discuss the evidence of the effect of fecal transplantation on the metabolic syndrome and MAFLD, as well as its clinical indications.

Faecal microbiota transplantation in endocrine diseases and obesity

The prevalence of type 1 (T1D) and type 2 diabetes mellitus (T2D) has greatly increased worldwide over the last century. Although the exact pathophysiology of both these conditions is distinct and still largely unknown, T1D as well as T2D, have been linked to distinct perturbations of the gut microbiome. Faecal microbiota transplantation (FMT) is a potent, and if performed well, a safe method to modulate the composition of the gut microbiome and thus positively influences the course of these hyperglycaemic conditions in humans. In this review, we provide an overview of how FMT is commonly performed and summarise how this procedure may reduce the insulin-resistance driving T2D, and the underlying auto-immunity driving T1D. Insights derived from FMT studies in T1D and T2D may help identify beneficial microbiota and associated metabolites that may serve as future treatments for these conditions.

A Pilot Study for Metabolic Profiling of Obesity-Associated Microbial Gut Dysbiosis in Male Wistar Rats

Obesity is one of the most incident and concerning disease worldwide. Definite strategies to prevent obesity and related complications remain elusive. Among the risk factors of the onset of obesity, gut microbiota might play an important role in the pathogenesis of the disease, and it has received extensive attention because it affects the host metabolism. In this study, we aimed to define a metabolic profile of the segregated obesity-associated gut dysbiosis risk factor. The study of the metabolome, in an obesity-associated gut dysbiosis model, provides a relevant way for the discrimination on the different biomarkers in the obesity onset. Thus, we developed a model of this obesity risk factors through the transference of gut microbiota from obese to non-obese male Wistar rats and performed a subsequent metabolic analysis in the receptor rats. Our results showed alterations in the lipid metabolism in plasma and in the phenylalanine metabolism in urine. In consequence, we have identified metabolic changes characterized by: (1) an increase in DG:34:2 in plasma, a decrease in hippurate, (2) an increase in 3-HPPA, and (3) an increase in o-coumaric acid. Hereby, we propose these metabolites as a metabolic profile associated to a segregated dysbiosis state related to obesity disease.

Investigating causality with fecal microbiota transplantation in rodents: applications, recommendations and pitfalls

In recent years, studies investigating the role of the gut microbiota in health and diseases have increased enormously - making it essential to deepen and question the research methodology employed. Fecal microbiota transplantation (FMT) in rodent studies (either from human or animal donors) allows us to better understand the causal role of the intestinal microbiota across multiple fields. However, this technique lacks standardization and requires careful experimental design in order to obtain optimal results. By comparing several studies in which rodents are the final recipients of FMT, we summarize the common practices employed. In this review, we document the limitations of this method and highlight different parameters to be considered while designing FMT Studies. Standardizing this method is challenging, as it differs according to the research topic, but avoiding common pitfalls is feasible. Several methodological questions remain unanswered to this day and we offer a discussion on issues to be explored in future studies.

Wolffia globosa-Mankai Plant-Based Protein Contains Bioactive Vitamin B12 and Is Well Absorbed in Humans

Background: Rare plants that contain corrinoid compounds mostly comprise cobalamin analogues, which may compete with cobalamin (vitamin B₁₂ (B₁₂)) metabolism. We examined the presence of B₁₂ in a cultivated strain of an aquatic plant: Wolffia globosa (Mankai), and predicted functional pathways using gut-bioreactor, and the effects of long-term Mankai consumption as a partial meat substitute, on serum B₁₂ concentrations. Methods: We used microbiological assay, liquid-chromatography/electrospray-ionization-tandem-mass-spectrometry (LC-MS/MS), and anoxic bioreactors for the B₁₂ experiments. We explored the effect of a green Mediterranean/low-meat diet, containing 100 g of frozen Mankai shake/day, on serum B₁₂ levels during the 18-month DIRECT-PLUS (ID:NCT03020186) weight-loss trial, compared with control and Mediterranean diet groups. Results: The B₁₂ content of Mankai was consistent at different seasons (p = 0.76). Several cobalamin congeners (Hydroxocobalamin(OH-B₁₂); 5-deoxyadenosylcobalamin(Ado-B₁₂); methylcobalamin(Me-B₁₂); cyanocobalamin(CN-B₁₂)) were identified in Mankai extracts, whereas no pseudo B₁₂ was detected. A higher abundance of 16S-rRNA gene amplicon sequences associated with a genome containing a KEGG ortholog involved in microbial B₁₂ metabolism were observed, compared with control bioreactors that lacked Mankai. Following the DIRECT-PLUS intervention (n = 294 participants; retention-rate = 89%; baseline B₁₂ = 420.5 ± 187.8 pg/mL), serum B₁₂ increased by 5.2% in control, 9.9% in Mediterranean, and 15.4% in Mankai-containing green Mediterranean/low-meat diets (p = 0.025 between extreme groups). Conclusions: Mankai plant contains bioactive B₁₂ compounds and could serve as a B₁₂ plant-based food source.