Short-Chain Fatty Acids and Human Health: From Metabolic Pathways to Current Therapeutic Implications.

The gastrointestinal tract is home to trillions of diverse microorganisms collectively known as the gut microbiota, which play a pivotal role in breaking down undigested foods, such as dietary fibers. Through the fermentation of these food components, short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate are produced, offering numerous health benefits to the host. The production and absorption of these SCFAs occur through various mechanisms within the human intestine, contingent upon the types of dietary fibers reaching the gut and the specific microorganisms engaged in fermentation. Medical literature extensively documents the supplementation of SCFAs, particularly butyrate, in the treatment of gastrointestinal, metabolic, cardiovascular, and gut-brain-related disorders. This review seeks to provide an overview of the dynamics involved in the production and absorption of acetate, propionate, and butyrate within the human gut. Additionally, it will focus on the pivotal roles these SCFAs play in promoting gastrointestinal and metabolic health, as well as their current therapeutic implications.

Association between Ustekinumab Trough Levels, Serum IL-22, and Oncostatin M Levels and Clinical and Biochemical Outcomes in Patients with Crohn's Disease.

Background: Ustekinumab (UST) has demonstrated effectiveness in treating patients with Crohn's disease. Monitoring treatment response can improve disease management and reduce healthcare costs. We investigated whether UST trough levels (TLs), serum IL22, and Oncostatin M (OSM) levels could be early indicators of non-response by analysing their correlation with clinical and biochemical outcomes in CD. Methods: Patients with CD initiating UST treatment from October 2018 to September 2020 were enrolled at six Italian centres for inflammatory bowel disease (IBD). Clinical and biochemical data were collected at four time points: baseline, second subcutaneous (SC) dose, fourth SC dose, and 52 weeks. TLs were measured during maintenance, at the second SC dose, and at the fourth SC dose. IL-22 and OSM serum levels were assessed at baseline and the second SC dose. We analysed whether TLs, IL22 levels, and OSM serum levels were associated with clinical response, clinical remission, biochemical remission, and endoscopic remission using the appropriate statistical tests. Results: Out of eighty-four initially enrolled patients, five were lost to follow-up, and eleven discontinued the drug before 52 weeks. At the 52-week time point, 47% achieved biochemical remission based on faecal calprotectin levels, and 61.8% achieved clinical remission. TLs at the second SC dose significantly correlated with biochemical remission at the same time point (p = 0.011). However, TLs did not correlate with clinical remission. Baseline OSM levels did not correlate with biochemical or clinical remission or response. IL22 levels notably decreased during UST therapy (p = 0.000), but its values did not correlate with biochemical or clinical remission. Conclusions: UST is an effective therapy for patients with CD. TLs measured at the second SC dose significantly correlated with biochemical remission, emphasising their potential role in treatment monitoring. Levels of OSM and IL-22, despite a significant decrease in the latter during therapy, did not exhibit correlations with clinical or biochemical outcomes in our study. Further studies are needed to confirm these findings.

The Role of the FODMAP Diet in IBS.

The low FODMAP (fermentable oligosaccharide, disaccharide, monosaccharide, and polyol) diet is a beneficial therapeutic approach for patients with irritable bowel syndrome (IBS). However, how the low FODMAP diet works is still not completely understood. These mechanisms encompass not only traditionally known factors such as luminal distension induced by gas and water but also recent evidence on the role of FOMAPs in the modulation of visceral hypersensitivity, increases in intestinal permeability, the induction of microbiota changes, and the production of short-chain fatty acids (SCFAs), as well as metabolomics and alterations in motility. Although most of the supporting evidence is of low quality, recent trials have confirmed its effectiveness, even though the majority of the evidence pertains only to the restriction phase and its effectiveness in relieving abdominal bloating and pain. This review examines potential pathophysiological mechanisms and provides an overview of the existing evidence on the effectiveness of the low FODMAP diet across various IBS subtypes. Key considerations for its use include the challenges and disadvantages associated with its practical implementation, including the need for professional guidance, variations in individual responses, concerns related to microbiota, nutritional deficiencies, the development of constipation, the necessity of excluding an eating disorder before commencing the diet, and the scarcity of long-term data. Despite its recognized efficacy in symptom management, acknowledging these limitations becomes imperative for a nuanced comprehension of the role of a low FODMAP diet in managing IBS. By investigating its potential mechanisms and evidence across IBS subtypes and addressing emerging modulations alongside limitations, this review aims to serve as a valuable resource for healthcare practitioners, researchers, and patients navigating the intricate landscape of IBS.

Primary sclerosing cholangitis and inflammatory bowel disease: a complicated yet unique relationship.

Primary sclerosing cholangitis (PSC) is a rare liver disorder characterized by biliary ducts inflammation, fibrosis and consequently chronic cholestasis, which progressively lead to liver cirrhosis. The main feature of PSC is the frequent association with inflammatory bowel disease (IBD), with an estimated prevalence of around 70% of the cases. This strong relationship seems due to the presence of shared pathogenetic mechanisms, which seem to involve the intestinal barrier function, the human gut microbiota and the immune innated and adaptative response to antigens derived from the bowel. Of relevance, PSC-IBD have specific clinical and pathological features that differ from PSC and IBD as separate entities, explaining the diversity in outcomes among these categories, and therefore the distinct clinical management that is required. The aim of this review is to present recent data regarding the epidemiology, pathobiology and clinical features of PSC-IBD.

Myths and Facts about Food Intolerance: A Narrative Review.

Most adverse reactions to food are patient self-reported and not based on validated tests but nevertheless lead to dietary restrictions, with patients believing that these restrictions will improve their symptoms and quality of life. We aimed to clarify the myths and reality of common food intolerances, giving clinicians a guide on diagnosing and treating these cases. We performed a narrative review of the latest evidence on the widespread food intolerances reported by our patients, giving indications on the clinical presentations, possible tests, and dietary suggestions, and underlining the myths and reality. While lactose intolerance and hereditary fructose intolerance are based on well-defined mechanisms and have validated diagnostic tests, non-coeliac gluten sensitivity and fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) intolerance are mainly based on patients' reports. Others, like non-hereditary fructose, sorbitol, and histamine intolerance, still need more evidence and often cause unnecessary dietary restrictions. Finally, the main outcome of the present review is that the medical community should work to reduce the spread of unvalidated tests, the leading cause of the problematic management of our patients.

Efficacy and safety of oral beclomethasone dipropionate and budesonide MMX versus 5-aminosalicylates or placebo in ulcerative colitis: a systematic review and meta-analysis.

Background: Low bioavailability steroids, including beclomethasone dipropionate (BDP) and budesonide MMX, have been developed to ensure colonic targeting and low systemic activity than systematic corticosteroids in treating patients with ulcerative colitis (UC). Objectives: This systematic review and meta-analysis evaluated the efficacy and safety of BDP and budesonide MMX® compared with 5-aminosalicylic acid (5-ASAs) or placebo, in patients with mild-to-moderate UC. Design: Systematic review and meta-analysis. Methods: We searched MEDLINE, EMBASE, and the Cochrane central register of controlled trials from inception to December 2021. We included all available randomized controlled trials (RCTs) comparing oral BDP or budesonide MMX with 5-ASAs or with placebo in induction of remission of mild-to-moderate UC. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Results: We identified two RCTs comparing BDP 5 mg with 5-ASA, one RCTs comparing BDP 10 mg with 5-ASA, two RCTs BDP 5 mg versus placebo, one RCT BDP 10 mg versus placebo, two RCTs budesonide MMX 9 mg versus 5-ASA, and six RCTs budesonide MMX 9 mg versus placebo. In terms of achieving clinical remission or improvement, BDP 5 mg, BDP 10 mg, and budesonide MMX 9 mg were more effective than placebo (OR 2.36, 95% CI 1.37-4.08; OR 2.23, 95% CI 1.02-4.87; and OR 2.03, 95% CI 1.45-2.85, respectively). The drugs were also more effective than placebo in achieving endoscopic remission. Regarding the comparisons with 5-ASA, we found no differences between 5-ASA and BDP 5 mg or BDP 10 mg or budesonide MMX 9 mg in achieving clinical remission or improvement (OR 0.90, 95% CI 0.51-1.57; OR 1.54, 95% CI 0.42-5.64; and OR 1.17, 95% CI 0.82-1.66). However, 5-ASA was more effective than budesonide MMX 9 mg in achieving histological remission (OR 0.33, 95% CI 0.16-0.70). Overall, all the drugs were safe and well tolerated. Conclusion: Low bioavailability steroids were more effective than placebo in achieving clinical remission, clinical and endoscopic remission, and histological remission. No differences were found between 5-ASA and BDP or budesonide MMX. Surely, more RCTs, also comparing BDP and budesonide MMX, are mandatory to confirm or not these results.

Extraintestinal Cancers in Inflammatory Bowel Disease: A Literature Review.

BACKGROUND: Inflammatory bowel disease (IBD) is a group of chronic multifactorial inflammatory disorders including two major entities: Crohn's disease (CD) and ulcerative colitis (UC). Preliminary evidence suggests that patients with IBD may be at increased risk of developing intestinal and extraintestinal cancers (EICs). Actually, little is known about the association between IBD and EICs, and there is ever-growing concern regarding the safety of immunomodulators and biological therapy, which may represent a risk factor for carcinogenesis. AIMS: The aim of this review is to summarize the evidence regarding the association between IBD and EICs, the safety of immunomodulators and biological therapy and the management of immunomodulators and biologic agents in IBD patients with prior or current EICs. RESULTS: IBD patients have a higher risk of developing different forms of extraintestinal solid organ tumors and hematological malignancies. Immunomodulators and biological therapy may increase the risk of developing some types of EICs and may be consciously used in patients with IBD and current or prior history of malignancy. CONCLUSIONS: Decisions regarding the use of immunomodulators or biological therapies should be made on an individual basis, considering a multidisciplinary approach involving oncologists.

Emerging Pharmaceutical Therapies to Address the Inadequacy of a Gluten-Free Diet for Celiac Disease.

Celiac disease (CeD) is a chronic autoimmune disorder triggered by the ingestion of gluten, affecting around 1% of the global population. It is a multifactorial disease involving both genetics and environmental factors. Nowadays, the only available treatment for CeD is a life-long gluten-free diet (GFD), which can cause a significant burden for patients, since symptoms and mucosal injury can persist despite apparent compliance with a GFD. This could also lead to psychological consequences and affect the quality of life of these patients. Thankfully, recent advances in understanding the pathogenesis of CeD and the availability of various targets have made it feasible to explore pharmaceutical treatments specific to CeD. Recently, the FDA has highlighted the unmet needs of adult patients on a GFD who experience ongoing symptoms attributed to CeD and also show persistent duodenal villous atrophy. This review will outline the limitations of a GFD, describe the targets of potential novel treatment of CeD and provide an overview of the primary clinical trials involving oral and injectable agents for a non-dietary treatment of CeD.