Immunological mechanisms underpinning faecal microbiota transplantation for the treatment of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease that results from a dysregulated immune response against specific environmental triggers in a genetically predisposed individual. Increasing evidence has indicated a causal role for changes in gut microbiota (dysbiosis) contributing to this immune-mediated intestinal inflammation. These mechanisms involve dysregulation of multiple facets of the host immune pathways that are potentially reversible. Faecal microbiota transplantation (FMT) is the transfer of processed stool from a healthy donor into an individual with an illness. FMT has shown promising results in both animal model experiments and clinical studies in IBD in the resolution of intestinal inflammation. The underlying mechanisms, however, are unclear. Insights from these studies have shown interactions between modulation of dysbiosis via changes in abundances of specific members of the gut microbial community and changes in host immunological pathways. Unravelling these causal relationships has promising potential for a translational therapy role to develop targeted microbial therapies and understand the mechanisms that underpin IBD aetiopathogenesis. In this review, we discuss current evidence for the contribution of gut microbiota in the disruption of intestinal immune homeostasis and immunoregulatory mechanisms that are associated with the resolution of inflammation through FMT in IBD.

The use of faecal microbiota transplant as treatment for recurrent or refractory Clostridioides difficile infection and other potential indications: second edition of joint British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS) guidelines.

The first British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS)-endorsed faecal microbiota transplant (FMT) guidelines were published in 2018. Over the past 5 years, there has been considerable growth in the evidence base (including publication of outcomes from large national FMT registries), necessitating an updated critical review of the literature and a second edition of the BSG/HIS FMT guidelines. These have been produced in accordance with National Institute for Health and Care Excellence-accredited methodology, thus have particular relevance for UK-based clinicians, but are intended to be of pertinence internationally. This second edition of the guidelines have been divided into recommendations, good practice points and recommendations against certain practices. With respect to FMT for Clostridioides difficile infection (CDI), key focus areas centred around timing of administration, increasing clinical experience of encapsulated FMT preparations and optimising donor screening. The latter topic is of particular relevance given the COVID-19 pandemic, and cases of patient morbidity and mortality resulting from FMT-related pathogen transmission. The guidelines also considered emergent literature on the use of FMT in non-CDI settings (including both gastrointestinal and non-gastrointestinal indications), reviewing relevant randomised controlled trials. Recommendations are provided regarding special areas (including compassionate FMT use), and considerations regarding the evolving landscape of FMT and microbiome therapeutics.

Results from the first English stool bank using faecal microbiota transplant as a medicinal product for the treatment of Clostridioides difficile infection.

BACKGROUND: Faecal Microbiota Transplant (FMT) has improved outcomes for the treatment of Clostridioides difficile infection (CDI) compared to antibiotic therapy. FMT is classified as a medicinal product in the United Kingdom, similar to the USA and Canada, limiting supply via stool banks without appropriate licencing. In the largest UK cohort to date, we describe the clinical outcomes for 124 patients receiving FMT for recurrent or refractory CDI and present a framework to produce FMT as a licenced medicinal product. METHODS: Anonymous unrelated healthy donors, screened via health assessment and microbiological testing donated stool. In aerobic conditions FMT aliquots were prepared for immediate use or frozen storage, following a production framework developed to comply with Good Manufacturing Practice. Outcome measures were clinical response to FMT defined as resolution of diarrhoea within seven days and clinical cure defined as response without diarrhoea recurrence at 90 days. FINDINGS: Clinical response was 83·9% (95% CI 76·0%-90·0%) after one treatment. Clinical cure was 78·2% (95% CI 67·4%-89·0%) across the cohort. Refractory cases appeared to have a lower initial clinical response rate compared to recurrent cases, however at day 90 there were no differences observed between these groups. INTERPRETATION: The methodology developed here enabled successful licencing of FMT by The Medicines and Healthcare products Regulatory Agency as a medicinal product. This has widened the availability of FMT in the National Health Service via a stool bank and can be applied in other centres across the world to improve access to safe and quality assured treatments.

Systematic review with meta-analysis: the efficacy of faecal microbiota transplantation for the treatment of recurrent and refractory Clostridium difficile infection.

BACKGROUND: Clostridium difficile infection (CDI) is the commonest nosocomial cause of diarrhoea. Faecal microbiota transplantation (FMT) is an approved treatment for recurrent or refractory CDI but there is uncertainty about its use. AIM: To evaluate the efficacy of FMT in treating recurrent and refractory CDI and investigate outcomes from modes of delivery and preparation. METHODS: A systematic review and meta-analysis was performed. MEDLINE, EMBASE, CINAHL, Cochrane Library, trial registers and conference proceedings were searched. Studies on FMT in recurrent and refractory CDI were included. The primary outcome was clinical resolution with subgroup analyses of modes of delivery and preparation. Random effects meta-analyses were used to combine data. RESULTS: Thirty seven studies were included; seven randomised controlled trials and 30 case series. FMT was more effective than vancomycin (RR: 0.23 95%CI 0.07-0.80) in resolving recurrent and refractory CDI. Clinical resolution across all studies was 92% (95%CI 89%-94%). A significant difference was observed between lower GI and upper GI delivery of FMT 95% (95%CI 92%-97%) vs 88% (95%CI 82%-94%) respectively (P=.02). There was no difference between fresh and frozen FMT 92% (95%CI 89%-95%) vs 93% (95%CI 87%-97%) respectively (P=.84). Administering consecutive courses of FMT following failure of first FMT resulted in an incremental effect. Donor screening was consistent but variability existed in recipient preparation and volume of FMT. Serious adverse events were uncommon. CONCLUSION: Faecal microbiota transplantation is an effective treatment for recurrent and refractory Clostridium difficile infection, independent of preparation and route of delivery.

Coeliac disease in South Asians resident in Britain: comparison with white Caucasian coeliac patients.

BACKGROUND: The catchment population of our hospital is ethnically diverse and we have seen a number of patients of South Asian origin with coeliac disease. We have suspected that there are differences compared with white Caucasian coeliacs, especially with respect to iron-deficiency anaemia and vitamin D deficiency at presentation. AIMS: To compare the clinical and laboratory features of South Asian adult coeliac patients with adult white Caucasian coeliacs. METHODS: We reviewed the notes of patients attending the adult coeliac clinic over the past 10 years. All patients were older than 16 years at diagnosis. There were 40 South Asians and 90 white Caucasians. Symptoms, haematology, biochemistry, endomysial antibody status, HLA alleles and small bowel histology at presentation were compared between the two racial groups. RESULTS: There were significant differences between the racial groups. South Asians were younger at presentation than the Caucasian patients (mean age 27 years compared with 47 years respectively, P<0.0001); they were less likely to have 'irritable bowel syndrome' symptoms (P<0.01), but more likely to have features of vitamin D deficiency (P<0.03). Their haemoglobin (P<0.05), mean cell volume (P<0.0004), serum iron (P<0.01), transferrin saturation (P<0.05), serum 1,25-dihydroxyvitamin D3 (P<0.002), and levels were lower, while serum alkaline phosphatase levels were higher (P<0.04) than in white Caucasian coeliac patients. There were no differences with respect to serum folate, vitamin B12, serum calcium, alanine aminotransferase and small bowel histology. IgA class endomysial antibody positivity was similar in the two groups (88.5% for South Asians compared with 73.5% for white Caucasians). White Caucasian patients were significantly more likely to be DQ2-positive than the South Asian patients (97.2% compared with 83.3%, P=0.02). CONCLUSION: South Asians with coeliac disease are less likely to present with 'irritable bowel syndrome' symptoms, but more likely to have features of vitamin D deficiency and iron deficiency, and have a higher alkaline phosphatase than white Caucasians. The differences in HLA alleles seen in South Asians with coeliac disease compared with white Caucasian patients suggests that among the South Asians, non-HLA regions may play a stronger role in disease susceptibility and presentation.

Long term continuous omeprazole treatment of patients with Barrett's oesophagus.

BACKGROUND: The metaplastic columnar epithelium in Barrett's oesophagus has malignant potential. AIM: To determine whether decreasing acid reflux leads to regression of Barrett's epithelium. METHOD: Twenty-four patients with Barrett's oesophagus were treated with omeprazole 20 mg o.m. in an open, prospective study; 11 were treated for 12 months, and 13 for 24 months. Another group of 17 patients with Barrett's oesophagus was treated with an H2-receptor antagonist in standard dosage for 12-36 (mean 23) months. Patients were assessed endoscopically. RESULTS: No evidence of significant shortening of the length of Barrett's oesophagus was seen in any patient treated for 12 or 24 months with omeprazole. Similarly, no shortening of the length of Barrett's oesophagus was seen in any patient treated with an H2-receptor antagonist. However, 6 of 11 patients treated with omeprazole for 12 months, and 7 of 13 treated for 24 months, developed macroscopic squamous islands visible below the squamo-columnar junction. This was not seen in any patient treated with an H2-receptor antagonist. CONCLUSION: Although there can be reappearance of squamous epithelium in Barrett's oesophagus of some patients during treatment with omeprazole 20 mg o.m. over 12-24 months, a significant shortening of the columnar lined segment is not seen.

Continuous treatment with omeprazole 20 mg daily for up to 6 years in Barrett's oesophagus.

BACKGROUND: Because of the malignant potential of Barrett's oesophagus, an aim of treatment is to cause the columnar epithelium to regress. A logical approach is to decrease acid reflux which is an important aetiological factor in Barrett's oesophagus. Treatment with omeprazole 20-80 mg over 1-3 years has yielded conflicting but largely disappointing results. AIM: To determine if treatment of Barrett's oesophagus with omeprazole 20 mg daily for up to 6 years can cause regression of the Barrett's epithelium. PATIENTS AND METHODS: Forty-seven patients with Barrett's oesophagus were treated in an open prospective study. Nine patients were treated for 2 years, 12 for 3 years, 10 for 4 years, eight for 5 years and eight for 6 years. Patients were endoscoped at 1-2-year intervals and endoscoped at the end of the treatment period. RESULTS: No significant shortening of the length of the Barrett's segment was seen during any treatment period, although omeprazole controlled reflux symptoms and was well tolerated. Macroscopic squamous islands appeared in 55% of patients, mostly in the first 2-3 years although in five patients they appeared later in treatment. CONCLUSION: Treatment of Barrett's oesophagus with omeprazole 20 mg daily for periods of up to 6 years did not cause regression in the length of the Barrett's segment, but it did lead in over half of the patients to partial re-epithelialization in the form of squamous islands.

An analytical method for the quantitation of mannitol and disaccharides in serum: a potentially useful technique in measuring small intestinal permeability in vivo.

An electrochemical-HPLC method for the determination of mannitol and lactulose is presented which may facilitate routine testing of intestinal permeability by requiring only a single blood sample instead of a 6-hour urine collection. Chromatographic conditions are described which allow separation of the closely related sugars lactulose and the dietary disaccharides lactose and sucrose. Preliminary results in normal controls and patients with untreated coeliac disease are presented.

Small intestinal lactase status, frequency distribution of enzyme activity and milk intake in a multi-ethnic population.

The aims of the study were to investigate the prevalence of primary lactase deficiency, frequency distribution of lactase activity and the relationship between lactose intake and lactase activity in three ethnic groups resident in Birmingham. Seventy-two white, 103 Indian and 58 Afro-Caribbean adult dyspeptic patients had distal duodenal biopsies taken for disaccharidase assay at endoscopy. Ten percent of whites, 51% Indians and 81% Afro-Caribbeans had primary lactase deficiency (sucrase/lactase ratio > 4). There was a generalized unexplained depression of disaccharidase activities in the Indians. Frequency distribution of lactase activity for the whole population showed a negative skew without evidence of trimodality. Lactose intake and symptoms attributed to lactose were assessed in a subgroup of 20 whites, 20 Indians and 18 Afro-Caribbeans by questionnaire. Lactose intake did not differ between lactase persistent and deficient subjects both within each racial group and between the groups. Diarrhoea, bloating and cramps were not significantly more common in lactase deficient than lactase persistent individuals.

Deferasirox (ICL670A) effectively inhibits oesophageal cancer growth in vitro and in vivo.

BACKGROUND AND PURPOSE: Growing evidence implicates iron in the aetiology of gastrointestinal cancer. Furthermore, studies demonstrate that iron chelators possess potent anti-tumour activity, although whether iron chelators show activity against oesophageal cancer is not known. EXPERIMENTAL APPROACH: The effect of the iron chelators, deferoxamine (DFO) and deferasirox, on cellular iron metabolism, viability and proliferation was assessed in two oesophageal adenocarcinoma cell lines, OE33 and OE19, and the squamous oesophageal cell line, OE21. A murine xenograft model was employed to assess the effect of deferasirox on oesophageal tumour burden. The ability of chelators to overcome chemoresistance and to enhance the efficacy of standard chemotherapeutic agents (cisplatin, fluorouracil and epirubicin) was also assessed. KEY RESULTS: Deferasirox and DFO effectively inhibited cellular iron acquisition and promoted intracellular iron mobilization. The resulting reduction in cellular iron levels was reflected by increased transferrin receptor 1 expression and reduced cellular viability and proliferation. Treating oesophageal tumour cell lines with an iron chelator in addition to a standard chemotherapeutic agent resulted in a reduction in cellular viability and proliferation compared with the chemotherapeutic agent alone. Both DFO and deferasirox were able to overcome cisplatin resistance. Furthermore, in human xenograft models, deferasirox was able to significantly suppress tumour growth, which was associated with decreased tumour iron levels. CONCLUSIONS AND IMPLICATIONS: The clinically established iron chelators, DFO and deferasirox, effectively deplete iron from oesophageal tumour cells, resulting in growth suppression. These data provide a platform for assessing the utility of these chelators in the treatment of oesophageal cancer patients.

Diffusion of polyethylene glycol-400 across lipid barriers in vitro.

1. Polyethylene glycol has been used extensively as a probe to measure passive small-intestinal permeability in vivo. However, there has been some uncertainty as to its suitability for use as an indicator of the permeation of water-soluble molecules across the intestinal wall because it seems to traverse the mucosa in much greater quantities than sugar molecules of equivalent M(r). 2. We have measured the permeation of polyethylene glycol-400 and lactulose from aqueous solution across pure lipid solvents in vitro. We found considerable transport of polyethylene glycol-400 across chloroform (1.03 g h-1 m-2) but no movement across petroleum ether. 3. However, in a separate experiment in which phospholipid (egg lecithin) was dissolved in the petroleum ether, permeation of polyethylene glycol-400 did occur (0.13 g h-1 m2), implying interaction of polyethylene glycol-400 with the phospholipid. No permeation of lactulose was seen in any of the experiments. 4. Our results suggest that, because of its interaction with lipid solvents, polyethylene glycol-400 is unsuitable as a probe to measure passive intestinal permeability in vivo.

Phytase activity in the human and rat small intestine.

Phytate is the major storage form of phosphorus in seeds and so is a common dietary constituent. Excessive ingestion of undegraded phytates can cause mineral deficiencies in humans. In addition, phytic acid is antineoplastic in animal models of both colon and breast carcinoma. There have been no previous studies quantifying phytase activity in the human small intestine although it is present in animals. Small intestinal phytase and alkaline phosphatase activity and distribution was measured in vitro in mucosal homogenates from two human small intestinal specimens obtained from transplant donors. Rat intestine was also studied for comparison. Phytase activity was found in human small intestine at low values (30 times less than that in rat tissue and 1000-fold lower than alkaline phosphatase in the same tissue). The activity was greatest in the duodenum and lowest in the ileum. In conclusion, the normal human small intestine has very limited ability to digest undegraded phytates. Although this may have adverse nutritional consequences with respect to metabolic cation imbalances, the presence of undigested phytate in the colon may protect against the development of colonic carcinoma.

Ethnic differences in cirrhosis of the liver in a British city: alcoholic cirrhosis in South Asian men.

AIMS AND METHODS: We studied the ethnic origin of cirrhotic patients retrospectively over the 14-year period 1987-2000 and compared the ethnic make-up of the cirrhotic patients with the ethnic make-up of the local catchment population. RESULTS AND CONCLUSIONS: Of 381 cirrhotics, 64.1% were white, 29.1% South Asian, 4.7% Afro-Caribbeans and 2.1% other races. These proportions were different from those of the local community in that South Asians were over-represented and Afro-Caribbeans were under-represented. Alcohol was the commonest cause of cirrhosis (60.9%) and South Asian non-Moslem males with alcoholic cirrhosis were over-represented and were younger at diagnosis than white alcoholic cirrhotics.

Small intestinal permeability to mannitol and lactulose in the three ethnic groups resident in west Birmingham.

BACKGROUND/AIMS: Asymptomatic residents of tropical countries have differences in small intestinal morphology and permeability compared with residents of temperate zones. The aim of this study was to investigate small intestinal permeability and morphology in three ethnic groups resident in Birmingham, UK. METHODS: 28 white patients, 101 Indian (Indian subcontinent), and 49 Afro-Caribbean adult patients with dyspepsia had endoscopic distal duodenal biopsies and a hyperosmolar lactulose/mannitol permeability test. Twenty normal white subjects had the permeability test. RESULTS: Lactulose/mannitol excretion ratios (LMER) were: white subjects 0.022 (median), white patients 0.022, Indians 0.031, Afro-Caribbeans 0.033. Differences between the immigrant groups and the two white groups were significant (p < 0.001); 33% of Indians and 45% of Afro-Caribbeans had LMER outside the range of the white groups. Afro-Caribbeans born in the UK had significantly lower LMER than those born abroad (p < 0.05); a similar trend was seen in Indians. Villous height/mucosal thickness ratios, calculated from small intestinal biopsy specimens, were lower in the immigrant groups and correlated inversely with LMER (r = 0.28; p < 0.05). Time resident in the tropics also correlated inversely with LMER. CONCLUSIONS: There were significant differences in small intestinal permeability and morphology between immigrants resident in a Western country and the native white population. The data suggested that these differences were related to environmental factors.

Effect of water-loading on the performance of polyethylene glycol as a marker of small intestinal permeability.

1. Polyethylene glycol has been used extensively to measure small intestinal permeability in vivo. However, polyethylene glycol seems to traverse the intestinal mucosa in much greater quantities than sugar molecules of equivalent M(r). In addition, the recovery of the lowest M(r) polymers of administered polyethylene glycol has been found to be both low and unreliable. 2. To compare the behaviour of a range of polyethylene glycol polymers with sugar probes in vivo, a combined polyethylene glycol/mannitol/lactulose probe was administered sequentially to healthy individuals in the fasted state and under conditions of water-loading. Timed hourly urine collections were made for 6 h. 3. Mannitol and lactulose recoveries were all within the normal range and were unaffected by co-administration of water. The lactulose/mannitol recovery ratios did not vary significantly over the 6 h collection period. In contrast, the recovery of total polyethylene glycol was significantly greater when subjects were water-loaded. Furthermore, proportionally greater quantities of polyethylene glycol M(r) 370 than M(r) 854 were recovered towards the end of the collection period than at the start. 4. Our results show that, in contrast to lactulose and mannitol, excretion of low-medium M(r) polyethylene glycol polymers is highly dependent on co-administration of water. Furthermore, the differential rate of excretion of the low compared with the high M(r) polyethylene glycol polymers suggests that the volume of distribution of the individual polymers may vary with M(r), and smaller polyethylene glycol molecules may undergo considerable renal tubular reabsorption.

Symptomatic cardiomyopathy as a presentation in Whipple's disease.

A patient presenting with congestive cardiac failure and anaemia underwent investigation which led to the diagnosis of Whipple's disease, associated with dilated cardiomyopathy. Conventional antibiotic therapy for Whipple's disease resulted in resolution of the traditional features of Whipple's disease and a marked improvement in the patient's heart failure.

Reduced cadherin/catenin complex expression in celiac disease can be reproduced in vitro by cytokine stimulation.

Celiac disease is characterized by a chronic immune response to dietary gluten, in which T cell responses result in elevated mucosal levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, interferon (IFN)-gamma, and transforming growth factor (TGF)-beta, which induce profound mucosal remodeling associated with increased enterocyte proliferation, apoptosis, and migration. Reduced intestinal expression of the morphoregulatory cell adhesion molecule E-cadherin, which forms complexes with beta-catenin, can increase enterocyte proliferation and migration. However, its mechanism of action in gastrointestinal inflammatory conditions and any involvement in celiac disease is unknown. In this study, we describe changes in E-cadherin and beta-catenin expression in celiac disease tissue and determine the effect of cytokines on their expression in an in vitro model. We assessed E-cadherin and beta-catenin expression in intestinal biopsies from 24 patients with celiac disease, 12 patients with treated celiac disease, and 10 healthy patients by immunohistochemistry, Western blotting, and confocal microscopy. Using Caco-2 cells, we examined the effect of TNF-alpha, IL-1, IFN-gamma, and TGF-beta on E-cadherin expression. E-cadherin transcription was assessed in both intestinal biopsies and Caco-2 cells by in situ hybridization and RT-PCR, respectively. A marked reduction in protein expression of E-cadherin and beta-catenin that returns to normal levels after treatment was observed in celiac disease; this reduction was associated with reduced levels of E-cadherin mRNA. E-cadherin expression in Caco-2 cells was significantly reduced after TNF-alpha, IL-1, and IFN-gamma stimulation. The effect of TNF-alpha on E-cadherin expression was maximal after stimulation for 48 hours and also induced modest reductions in beta-catenin expression. The action of TNF-alpha on E-cadherin was reversible and was shown to act at the transcriptional level. These results demonstrate the novel findings that E-cadherin and beta-catenin expression are reversibly down-regulated in celiac disease and that such changes in epithelial cadherin/catenin complexes may be mediated by cytokines acting on cadherin transcription.

Lactase haplotype frequencies in Caucasians: association with the lactase persistence/non-persistence polymorphism.

A genetic polymorphism is responsible for determining that some humans express lactase at high levels throughout their lives and are thus lactose tolerant, while others lose lactase expression during childhood and are lactose intolerant. We have previously shown that this polymorphism is controlled by an element or elements which act in cis to the lactase gene. We have also reported that 7 polymorphisms in the lactase gene are highly associated and lead to only 3 common haplotypes (A, B and C) in individuals of European extraction. Here we report the frequencies of these polymorphisms in Caucasians from north and south Europe and also from the Indian sub-continent, and show that the alleles differ in frequency, the B and C haplotypes being much more common in southern Europe and India. Allelic association studies with lactase persistence and non-persistence phenotypes show suggestive evidence of association of lactase persistence with certain alleles. This association was rather more clear in the analysis of small families, where haplotypes could be determined. Furthermore haplotype and RNA transcript analysis of 11 unrelated lactase persistent individuals shows that the persistence (highly expressed) allele is almost always on the A haplotype background. Non-persistence is found on a variety of haplotypes including A. Thus it appears that lactase persistence arose more recently than the DNA marker polymorphisms used here to define the main Caucasian haplotypes, possibly as a single mutation on the A haplotype background. The high frequency of the A haplotype in northern Europeans is consistent with the high frequency of lactase persistence.