Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota.

Short-chain fatty acids (SCFAs) play a key role in health and disease, as they regulate gut homeostasis and their deficiency is involved in the pathogenesis of several disorders, including inflammatory bowel diseases, colorectal cancer, and cardiometabolic disorders. SCFAs are metabolites of specific bacterial taxa of the human gut microbiota, and their production is influenced by specific foods or food supplements, mainly prebiotics, by the direct fostering of these taxa. This Review provides an overview of SCFAs' roles and functions, and of SCFA-producing bacteria, from their microbiological characteristics and taxonomy to the biochemical process that lead to the release of SCFAs. Moreover, we will describe the potential therapeutic approaches to boost the levels of SCFAs in the human gut and treat different related diseases.

Efficacy of different faecal microbiota transplantation protocols for Clostridium difficile infection: A systematic review and meta-analysis.

BACKGROUND: Protocols for treating recurrent Clostridium difficile infection (rCDI) through faecal microbiota transplantation (FMT) are still not standardised. Our aim was to evaluate the efficacy of different FMT protocols for rCDI according to routes, number of infusions and infused material. METHODS: MEDLINE, Embase, SCOPUS, Web of Science and the Cochrane Library were searched through 31 May 2017. Studies offering multiple infusions if a single infusion failed to cure rCDI were included. Data were combined through a random effects meta-analysis. RESULTS: Fifteen studies (1150 subjects) were analysed. Multiple infusions increased efficacy rates overall (76% versus 93%) and in each route of delivery (duodenal delivery: 73% with single infusion versus 81% with multiple infusions; capsule: 80% versus 92%; colonoscopy: 78% versus 98% and enema: 56% versus 92%). Duodenal delivery and colonoscopy were associated, respectively, with lower efficacy rates (p = 0.039) and higher efficacy rates (p = 0.006) overall. Faecal amount ≤ 50 g (p = 0.006) and enema (p = 0.019) were associated with lower efficacy rates after a single infusion. The use of fresh or frozen faeces did not influence outcomes. CONCLUSIONS: Routes, number of infusions and faecal dosage may influence efficacy rates of FMT for rCDI. These findings could help to optimise FMT protocols in clinical practice.

Probiotics, fibre and herbal medicinal products for functional and inflammatory bowel disorders.

Functional bowel disorders (FBD), mainly irritable bowel syndrome (IBS) and functional constipation (FC, also called chronic idiopathic constipation), are very common worldwide. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, although less common, has a strong impact on patients' quality of life, as well as being highly expensive for our healthcare. A definite cure for those disorders is still yet to come. Over the years, several therapeutic approaches complementary or alternative to traditional pharmacological treatments, including probiotics, prebiotics, synbiotics, fibre and herbal medicinal products, have been investigated for the management of both groups of diseases. However, most available studies are biased by several drawbacks, including small samples and poor methodological quality. Probiotics, in particular Saccharomyces boulardii and Lactobacilli (among which Lactobacillus rhamnosus), synbiotics, psyllium, and some herbal medicinal products, primarily peppermint oil, seem to be effective in ameliorating IBS symptoms. Synbiotics and fibre seem to be beneficial in FC patients. The probiotic combination VSL#3 may be effective in inducing remission in patients with mild-to-moderate ulcerative colitis, in whom Escherichia coli Nissle 1917 seems to be as effective as mesalamine in maintaining remission. No definite conclusions can be drawn as to the efficacy of fibre and herbal medicinal products in IBD patients due to the low number of studies and the lack of randomized controlled trials that replicate the results obtained in the individual studies conducted so far. Thus, further, well-designed studies are needed to address the real role of these therapeutic options in the management of both FBD and IBD. LINKED ARTICLES: This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Role and mechanisms of action of Escherichia coli Nissle 1917 in the maintenance of remission in ulcerative colitis patients: An update.

Ulcerative colitis (UC) is a chronic inflammatory disease, whose etiology is still unclear. Its pathogenesis involves an interaction between genetic factors, immune response and the "forgotten organ", Gut Microbiota. Several studies have been conducted to assess the role of antibiotics and probiotics as additional or alternative therapies for Ulcerative Colitis. Escherichia coli Nissle (EcN) is a nonpathogenic Gram-negative strain isolated in 1917 by Alfred Nissle and it is the active component of microbial drug Mutaflor(®) (Ardeypharm GmbH, Herdecke, Germany and EcN, Cadigroup, In Italy) used in many gastrointestinal disorder including diarrhea, uncomplicated diverticular disease and UC. It is the only probiotic recommended in ECCO guidelines as effective alternative to mesalazine in maintenance of remission in UC patients. In this review we propose an update on the role of EcN 1917 in maintenance of remission in UC patients, including data about efficacy and safety. Further studies may be helpful for this subject to further the full use of potential of EcN.

Digestive Enzyme Supplementation in Gastrointestinal Diseases.

BACKGROUND: Digestive enzymes are able to break down proteins and carbohydrates and lipids, and their supplementation may play a role in the management of digestive disorders, from lactose intolerance to cystic fibrosis. To date, several formulations of digestive enzymes are available on the market, being different each other in terms of enzyme type, source and origin, and dosage. METHODS: This review, performed through a non-systematic search of the available literature, will provide an overview of the current knowledge of digestive enzyme supplementation in gastrointestinal disorders, discussion of the use of pancreatic enzymes, lactase (ß-galactosidase) and conjugated bile acids, and also exploring the future perspective of digestive enzyme supplementation. RESULTS: Currently, the animal-derived enzymes represent an established standard of care, however the growing study of plant-based and microbe-derived enzymes offers great promise in the advancement of digestive enzyme therapy. CONCLUSION: New frontiers of enzyme replacement are being evaluated also in the treatment of diseases not specifically related to enzyme deficiency, whereas the combination of different enzymes might constitute an intriguing therapeutic option in the future.

The involvement of gut microbiota in inflammatory bowel disease pathogenesis: potential for therapy.

Over the past recent years, a great number of studies have been directed toward the evaluation of the human host-gut microbiota interaction, with the goal to progress the understanding of the etiology of several complex diseases. Alterations in the intestinal microbiota associated with inflammatory bowel disease are well supported by literature data and have been widely accepted by the research community. The concomitant implementation of high-throughput sequencing techniques to analyze and characterize the composition of the intestinal microbiota has reinforced the view that inflammatory bowel disease results from altered interactions between gut microbes and the mucosal immune system and has raised the possibility that some form of modulation of the intestinal microbiota may constitute a potential therapeutic basis for the disease. The aim of this review is to describe the changes of gut microbiota in inflammatory bowel disease, focusing the attention on its involvement in the pathogenesis of the disease, and to review and discuss the therapeutic potential to modify the intestinal microbial population with antibiotics, probiotics, prebiotics, synbiotics and fecal microbiota transplantation.

Fecal microbiota transplantation: a new old kid on the block for the management of gut microbiota-related disease.

Gut microbiota is deeply involved in the regulation of both health and disease within our body. The restoration of a healthy gut microbiota is, therefore, a main clinical target in the management of diseases associated with its disruption. Fecal microbiota transplantation (FMT) is an old therapy that has recently been rediscovered, having proved a clear efficacy against recurrent Clostridium difficile infection. By restoring the altered gut microbiota in a substantial and durable manner, FMT is considered a cutting-edge promising option for the treatment of disease that recognize the alteration of the gut microbiota as having a pathogenic role. FMT has shown interesting (even if uncertain) results in diseases such as metabolic syndrome and inflammatory bowel diseases. Moreover, the definition of a standard procedural protocol for each specific disease, as well as exhaustive studies about the relationship between donor's microbiota composition and clinical results, will certainly improve the therapeutic potential of FMT. Both the application of cutting-edge technologies for the assessment of gut microbiota composition (such as metagenomics) and the development of well-designed, large randomized trials are needed to put such perspectives into practice.

Fecal microbiota transplantation in inflammatory bowel disease: beyond the excitement.

The purpose of this article is to perform a systematic review of the literature on the use of fecal microbiota transplantation (FMT) in inflammatory bowel disease (IBD).There is an increasing interest of both physicians and patients in assessing the possible role of the FMT in the treatment of IBD.Electronic and manual bibliographic searches were performed to identify original reports in which subjects with IBD were treated with FMT. Because of the scarcity of studies with adequate sample size, case series and case reports were also considered. A critical appraisal of the clinical research evidence on the effectiveness, safety, and other parameters related to FMT was made. Data extraction was independently performed by 2 reviewers.We found a total of 31 publications on the use of FMT in IBD. The majority were case reports or case series, whereas 8 publications reported data from open-label trials including a very less number of patients. A total of 133 patients with IBD were managed with FMT. Of these, 57 subjects (43%) had a Clostridium difficile infection. A resolution or reduction of symptoms was reported in 80 of 113 (71%) patients with evaluable IBD. Moreover, FMT does not seem to provide the same safety profile showed for non-IBD individuals with C difficile infection.The available evidence is limited and weak. FMT has the potential to be somehow of help in managing patients with IBD, but considerable further efforts are necessary to make this procedure a valid option for these subjects.

Culture-guided treatment approach for Helicobacter pylori infection: review of the literature.

The progressive loss of efficacy of standard eradication therapies has made the treatment of Helicobacter pylori (H. pylori) more challenging than ever. Endoscopic-guided antibiotic susceptibility testing had previously been suggested to guide treatment after failure of second-line therapies. However, its role has expanded over the years, in accordance with the current Maastricht Guidelines. Several authors have dealt with this topic, developing both efficacy trials and cost-effectiveness trials against resistant H. pylori infections as well as infections in naïve patients. However, results are not homogeneous enough to provide definite advice, because antibiotic resistance is not the only reason for treatment failure. Moreover, the culture-guided approach is surrounded by many practical issues, such as the availability of both endoscopy units and microbiology laboratories, and the need for a standard of quality that cannot be satisfied everywhere. Finally, pre-treatment susceptibility testing should be part - and not the only weapon - of a targeted, personalized strategy to overcome H. pylori infection.

Fecal microbiota transplantation for the treatment of Clostridium difficile infection: a systematic review.

GOAL: By systematic review, we assessed the impact of fecal microbiota transplantation (FMT) for the treatment of Clostridium difficile (CD)-associated diarrhea. BACKGROUND: Fecal microbiota microbiota transplantation from a healthy donor into an individual with CD infection (CDI) can resolve symptoms. STUDY: We conducted systematic searches in PubMed, SCOPUS, Web of Science, and Cochrane Library. The last search was run on February 8, 2013. The following Medical Subject Headings terms and keywords were used alone or in combination: Clostridium difficile; Clostridium infection; pseudomembranous colitis; feces; stools; fecal suspension; fecal transplantation; fecal transfer; fecal infusion; microbiota; bacteriotherapy; enema; nasogastric tube; colonoscopy; gastroscopy; fecal donation; donor. A critical appraisal of the clinical research evidence on the effectiveness and safety of FMT for the treatment of patients with CD-associated diarrhea was made. RESULTS: Twenty full-text case series, 15 case reports, and 1 randomized controlled study were included for the final analysis. Almost all patients treated with donors' fecal infusion experienced recurrent episodes of CD-associated diarrhea despite standard antibiotic treatment. Of a total of 536 patients treated, 467 (87%) experienced resolution of diarrhea. Diarrhea resolution rates varied according to the site of infusion: 81% in the stomach; 86% in the duodenum/jejunum; 93% in the cecum/ascending colon; and 84% in the distal colon. No severe adverse events were reported with the procedure. CONCLUSIONS: FMT seems efficacious and safe for the treatment of recurrent CDI. Hospitals should encourage the development of fecal transplantation programs to improve therapy of local patients.

Locally injected Infliximab ameliorates murine DSS colitis: differences in serum and intestinal levels of drug between healthy and colitic mice.

BACKGROUND: Infliximab is effective in human and murine IBD, but its pharmacodynamic is still poorly known. The aim of this study was to assess the affinity of infliximab to murine TNF-α, its role in murine colitis when administered intra-rectally and its levels in the blood, gut mucosa and stool of healthy and sick mice. METHODS: An ELISA kit was built in order to assess the affinity of infliximab to human or murine-TNF-α. Human IgG were used as controls. DSS model of colitis on C57BL/6 mice was used to assess clinical efficacy of infliximab administered intravenously or by enema. Stool, serum and colon samples were collected to assess infliximab levels and histology for Rachmilewitz score. RESULTS: Infliximab showed a good affinity both for human-TNF-α and murine-TNF-α. In DSS colitic mice infliximab ameliorated the severity of colitis, regardless of the administration route. In comparison with colitic mice, healthy mice displayed higher serum and mucosal infliximab levels, while detectable levels of infliximab were found in faeces, particularly in colitic mice. CONCLUSION: Our data support murine models to study infliximab pharmacokinetics and dynamics. Measurable levels of infliximab can be found at different concentrations in blood, intestinal mucosa and stool from healthy and sick mice, thus infliximab pharmacokinetics could have a major impact in human IBD.

High levels of dual resistance to clarithromycin and metronidazole and in vitro activity of levofloxacin against Helicobacter pylori isolates from patients after failure of therapy.

Current treatment for Helicobacter pylori infections generally includes two or more antimicrobials (amoxicillin, clarithromycin, nitroimidazoles, tetracycline, etc.), but treatment fails in 10-20% of all cases, often because of drug resistance. Levofloxacin has been proposed as an alternative for these refractory infections. We examined 67 H. pylori isolates from patients unsuccessfully treated with amoxicillin, clarithromycin, metronidazole and levofloxacin. Minimum inhibitory concentrations determined with the epsilometer test revealed clarithromycin and metronidazole resistance in 91 and 82.1% of the isolates, respectively; 52 (77.6%) were resistant to both drugs. All 67 isolates were susceptible to amoxicillin and tetracycline. Fifty-two isolates had levofloxacin MICs of 0.01-2 mg/l; the remaining 15 (22.4%), all clarithromycin- and metronidazole-resistant, had MICs >/= 8 mg/l. Levofloxacin may be an option for refractory H. pylori infections, but the choice should be based on in vitro susceptibility data, and physicians should consider local resistance patterns when treating these infections empirically.

High-dose versus low-dose clarithromycin in 1-week triple therapy, including rabeprazole and levofloxacin, for Helicobacter pylori eradication.

GOALS: To compare high-dose versus low-dose clarithromycin in 1-week triple therapy including rabeprazole and levofloxacin. BACKGROUND: Regimens containing rabeprazole and levofloxacin have proved to be effective against H. pylori infection. STUDY: One-hundred H. pylori-positive patients were randomly assigned to one of the following 1-week regimens: rabeprazole 20 mg o.d. plus levofloxacin 500 mg o.d. and clarithromycin 250 mg b.d. (RLC-1 group); rabeprazole 20 mg o.d. plus levofloxacin 500 mg o.d. and clarithromycin 500 mg b.d. (RLC-2 group). H. pylori status was assessed at entry and after the treatment. Patients who experienced treatment failure underwent antibiotic susceptibility testing. RESULTS: Forty-two patients in RLC-1 group (both PP and ITT analysis: 84%; 95%CI: 71-93%) and 47 in RLC2 group (both PP and ITT analysis: 94%; 95% CI: 83-98%) became H. pylori negative. Clarithromycin resistance was detected in all of 8 (100%) RLC-1 failures and in 1 out of 3 (33%) RLC-2 failures. Side effects occurred in 8% of patients in RLC-1 group and in 12% in RLC-2. CONCLUSIONS: Regimens tested are competitive with other PPI-based treatments. One-week triple therapy containing rabeprazole plus, levofloxacin, and high-dose clarithromycin yielded a higher eradicating rate than the one containing low-dose clarithromycin and may be considered as a first-line therapy option.