Potential mechanisms of effects of serum-derived bovine immunoglobulin/protein isolate therapy in patients with diarrhea-predominant irritable bowel syndrome

Integrative Approaches to Managing Gut Health

PURPOSE OF REVIEW

To summarize key integrative approaches to managing common gastrointestinal conditions.

RECENT FINDINGS

Lifestyle interventions like diet, exercise, and stress reduction impact the gut microbiome and gastrointestinal symptoms. Evidence supports mind-body therapies, herbs, certain supplements, and other modalities as complimentary approaches, when appropriate, for common conditions like irritable bowel syndrome or gastroesophageal reflux disease. An integrative approach optimizes both conventional treatments and incorporates lifestyle modifications, complimentary modalities, and the doctor-patient relationship.

Role of autoantibodies in the pathophysiology of irritable bowel syndrome: a review

Irritable bowel syndrome (IBS) is a chronic, recurrent disorder that is characterized by abdominal pain associated with defecation. IBS was previously considered to manifest without any structural alterations until the discovery of post-infection IBS. An increasing body of published evidence indicates that immune activation plays an important role in the development of IBS. Nevertheless, the pathophysiology of IBS, including mainly visceral hypersensitivity and gastrointestinal dysmotility, has not yet been explicitly elucidated. The observation of potential inflammatory degenerative neuropathy, including neuronal degeneration, spearheaded research on autoimmune responses targeting the enteric nervous system. Subsequently, several autoantibodies were detected in the sera of IBS patients, among which some were presumed to exert a pathogenic influence or be associated with the etiology of gastrointestinal dysmotility in IBS. Moreover, certain specific autoantibodies evidently served as biomarkers to facilitate the differentiation between IBS and other related diseases. Therefore, we aimed to present an overview of autoantibodies reported in the sera of IBS patients and highlight their significance in diagnosing and comprehending the pathophysiology of IBS. Consequently, we propose a therapeutic strategy from an autoimmune perspective.

Irritable Bowel Syndrome: Treating the Gut and Brain/Mind at the Same Time

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal (GI) disorders in the world. Although IBS does not affect a person's life span, it can significantly influence their quality of life. The treatment of IBS should be tailored to each patient's specific symptomatology because it can often be difficult to manage. Given that the pathogenesis of IBS is not well understood, it places a tremendous load on healthcare resources. Over the years, IBS has been described as either a simple GI disorder or a more complex multi-symptomatic gut-brain axis disorder. Many persons with IBS have psychological issues in addition to gastrointestinal symptoms, offering the door to non-pharmacological therapies such as cognitive behavioral therapy, gut-directed hypnosis, or psychodynamic interpersonal therapy. Non-pharmacological therapies with no side effects should be used as first-line therapy. Diet, exercise, microbiota-targeted therapies, and psychological treatments are among the most significant interventions. This review goes into the details of all the non-pharmacological interventions that can be used to treat IBS.

Altered Gut Microbic Flora and Haemorrhoids: Could They Have a Possible Relationship?

To date, the exact pathophysiology of haemorrhoids is poorly understood. The different philosophies on haemorrhoids aetiology may lead to different approaches of treatment. A pathogenic theory involving a correlation between altered anal canal microflora, local inflammation, and muscular dyssynergia is proposed through an extensive review of the literature. Since the middle of the twentieth century, three main theories exist: (1) the varicose vein theory, (2) the vascular hyperplasia theory, and (3) the concept of a sliding anal lining. These phenomena determine changes in the connective tissue (linked to inflammation), including loss of organization, muscular hypertrophy, fragmentation of the anal subepithelial muscle and the elastin component, and vascular changes, including abnormal venous dilatation and vascular thrombosis. Recent studies have reported a possible involvement of gut microbiota in gut motility alteration. Furthermore, dysbiosis seems to represent the leading cause of bowel mucosa inflammation in any intestinal district. The alteration of the gut microbioma in the anorectal district could be responsible for haemorrhoids and other anorectal disorders. A deeper knowledge of the gut microbiota in anorectal disorders lays the basis for unveiling the roles of these various gut microbiota components in anorectal disorder pathogenesis and being conductive to instructing future therapeutics. The therapeutic strategy of antibiotics, prebiotics, probiotics, and fecal microbiota transplantation will benefit the effective application of precision microbiome manipulation in anorectal disorders.

Intestinal chemosensitivity in irritable bowel syndrome associates with small intestinal TRPV channel expression

BACKGROUND

Irritable bowel syndrome (IBS) patients often experience meal-associated symptoms. However, the underlying mechanisms are unclear.

AIM

To determine small intestinal mechanisms of lipid-induced symptoms and rectal hypersensitivity in IBS METHODS: We recruited 26 IBS patients (12 IBS-C, 14 IBS-D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe-based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics.

RESULTS

Following lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P < 0.05 for all). In a model adjusted for sex and anxiety, IBS-C and IBS-D patients had lower thresholds for first rectal sensation (P = 0.0007) and pain (P = 0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post-lipid, pCLE scores were higher than pre-lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS-D, and TRPV3 in IBS-C. Duodenal TRPV1 expression correlated with abdominal pain (r = 0.51, FDR = 0.01), and inversely with first rectal sensation (r = -0.48, FDR = 0.01) and pain (r = -0.41, FDR = 0.02) thresholds.

CONCLUSION

Lipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV-mediated small intestinal chemosensitivity may mediate post-meal symptoms in IBS.

Intestinal barrier dysfunction in irritable bowel syndrome: a systematic review

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is a complex and heterogeneous disorder. Sensory, motor and barrier dysfunctions are the key physiological endophenotypes of IBS. Our aim is to review studies evaluating barrier dysfunction in adults and children with IBS, as well as to link those changes with IBS symptomatology and quality of life.

METHODS

A comprehensive and systematic review of multiple databases was performed up to March 2020 to identify studies comparing intestinal permeability in IBS patients with healthy controls. Both in vivo and in vitro studies were considered.

RESULTS

We identified 66 studies, of which 27 used intestinal probes to quantify barrier function. The prevalence of barrier dysfunction differed between PI-IBS (17-50%), IBS-D (37-62%) and IBS-C (4-25%). At a group level, permeability was increased compared with healthy controls in IBS-D (9/13 studies) and PI-IBS (4/4 studies), but only a minority of IBS-C (2/7 studies) and not in the only IBS-M study. All four studies in children with IBS demonstrated loss of barrier function. A heterogeneous set of tight junction genes were found to be altered in small and large intestines of adults with IBS, but these have not been evaluated in children. Positive associations were identified between barrier dysfunction and bowel disturbances (6/9 studies), abdominal pain (9/13 studies), overall symptom severity (1/6 studies), depression and anxiety (1/1 study) and quality of life (1/4 studies). Fecal slurry or supernatants of IBS patients were found to induce barrier disruption in animal models (5/6 studies).

CONCLUSIONS

Barrier dysfunction is present in a significant proportion of adult and all pediatric IBS studies, especially in the IBS-D and PI-IBS subtype. The majority of studies indicated a positive association between loss of barrier function and symptoms such as abdominal pain and changes in the bowel function.

Functional Gastrointestinal Disorders and the Microbiome-What Is the Best Strategy for Moving Microbiome-based Therapies for Functional Gastrointestinal Disorders into the Clinic?

There have been numerous human studies reporting associations between the intestinal microbiome and functional gastrointestinal disorders (FGIDs), and independently animal studies have explored microbiome-driven mechanisms underlying FGIDs. However, there is often a disconnect between human and animal studies, which hampers translation of microbiome findings to the clinic. Changes in the microbiota composition of patients with FGIDs are generally subtle, whereas changes in microbial function, reflected in the fecal metabolome, appear to be more precise indicators of disease subtype-specific mechanisms. Although we have made significant progress in characterizing the microbiome, to effectively translate microbiome science in a timely manner, we need concurrent and iterative longitudinal studies in humans and animals to determine the precise microbial functions that can be targeted to address specific pathophysiological processes in FGIDs. A systems approach integrating multiple data layers rather than evaluating individual data layers of symptoms, physiological changes, or -omics data in isolation will allow for validation of mechanistic insights from animal studies while also allowing new discovery. Patient stratification for clinical trials based on functional microbiome alterations and/or pathophysiological measurements may allow for more accurate determination of efficacy of individual microbiome-targeted interventions designed to correct an underlying abnormality. In this review, we outline current approaches and knowledge, and identify gaps, to provide a potential roadmap for accelerating translation of microbiome science toward microbiome-targeted personalized treatments for FGIDs.

A Clostridia-rich microbiota enhances bile acid excretion in diarrhea-predominant irritable bowel syndrome

An excess of fecal bile acids (BAs) is thought to be one of the mechanisms for diarrhea-predominant irritable bowel syndrome (IBS-D). However, the factors causing excessive BA excretion remain incompletely studied. Given the importance of gut microbiota in BA metabolism, we hypothesized that gut dysbiosis might contribute to excessive BA excretion in IBS-D. By performing BA-related metabolic and metagenomic analyses in 290 IBS-D patients and 89 healthy volunteers, we found that 24.5% of IBS-D patients exhibited excessive excretion of total BAs and alteration of BA-transforming bacteria in feces. Notably, the increase in Clostridia bacteria (e.g., C. scindens) was positively associated with the levels of fecal BAs and serum 7α-hydroxy-4-cholesten-3-one (C4), but negatively correlated with serum fibroblast growth factor 19 (FGF19) concentration. Furthermore, colonization with Clostridia-rich IBS-D fecal microbiota or C. scindens individually enhanced serum C4 and hepatic conjugated BAs but reduced ileal FGF19 expression in mice. Inhibition of Clostridium species with vancomycin yielded opposite results. Clostridia-derived BAs suppressed the intestinal FGF19 expression in vitro and in vivo. In conclusion, this study demonstrates that the Clostridia-rich microbiota contributes to excessive BA excretion in IBS-D patients, which provides a mechanistic hypothesis with testable clinical implications.

The Evolving Role of Gut Microbiota in the Management of Irritable Bowel Syndrome: An Overview of the Current Knowledge

The intestinal microbiota is one of the most rapidly evolving areas in biology and medicine. Extensive research in the last decade has escalated our understanding of the role of the microbiota in the pathogenesis of several intestinal and extra-intestinal disorders. Marked by high prevalence, substantial morbidity, and enormous costs, irritable bowel syndrome (IBS) is an important chronic gastrointestinal disorder that is widely encountered by gastroenterologists. Despite advances in our understanding of its pathophysiology, curative interventions have yet to be discovered, and therapeutic approaches remain symptom-driven. Recently, accumulating evidence has enlightened the possible impact of an imbalanced gut microbiome in the pathogenesis of IBS. In fact, several studies have documented altered microbiota in patients, while others have shown that IBS severity was associated with a distinct microbiota signature. These findings may pave the way for the use of microbiota manipulation strategies as an attractive option for IBS management, and may have an essential role in efforts to reduce the societal and economic effects of this ever-growing disorder. In this review, we have outlined the results of the latest research on the association between microbiota and IBS and their implications for the clinical management of affected patients.

Management of irritable bowel syndrome with diarrhea: a review of nonpharmacological and pharmacological interventions

Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) condition involving numerous potential causative factors (e.g. alterations in gut microbiota, motility, brain-gut axis). Several interventions are available for the management of patients with IBS, but no universal management algorithm currently exists. The aim of this article is to review interventions that may be considered in the management of patients with IBS with diarrhea (IBS-D). Nonpharmacological interventions include dietary and lifestyle modification, which are generally used as first-line therapy. Probiotics have demonstrated efficacy and safety in patients with IBS, but studies are inconsistent in strains examined, dosing, and treatment duration. Psychological therapies (e.g. cognitive behavioral therapy, hypnotherapy) also may improve IBS symptoms. Pharmacological interventions for the management of IBS-D include the US Food and Drug Administration-approved agents eluxadoline, rifaximin, and alosetron, as well as loperamide, smooth muscle antispasmodics, bile acid sequestrants, and antidepressants (i.e. tricyclic antidepressants, selective serotonin reuptake inhibitors). Eluxadoline and rifaximin have been shown to improve abdominal pain and stool consistency in patients with IBS-D. In addition, data indicate that alosetron improves IBS symptoms; however, it is approved only for women with severe IBS-D. Of the three approved agents, rifaximin has the most favorable safety profile. The risk-benefit ratio is an important consideration with every medication, but is especially important in the treatment of functional GI disorders such as IBS-D. Thus, the most troublesome symptoms, quality of life, symptom intensity, and individual patient preferences should be considered when formulating a management plan for patients with IBS-D.

Proteobacteria Acts as a Pathogenic Risk-Factor for Chronic Abdominal Pain and Diarrhea in Post-Cholecystectomy Syndrome Patients: A Gut Microbiome Metabolomics Study

Background

Laparoscopic cholecystectomy (LC) is regarded as the criterion standard for gallstone therapy, but post-cholecystectomy syndrome (PCS) is a common complication. This study aimed to analyze and identify differences in gut microbiome in PCS patients.

Material/Methods

This study involved 8 PCS patients (RS1), 8 asymptomatic PCS patients (RS2), and 8 healthy individuals (RS3). Genomic DNA of gut microbiome was extracted and amplified with CTAB method. PCR products were sequenced with Illumina High-Through Sequencing. Sequencing data were analyzed with QIIME software. Effective sequence of bacterial 16S-rRNA gene was clustered into OTUs using UPARSE software. Species annotations were evaluated using Mothur software. QIIME software was used to conduct complexity analysis and calculate UniFrac distances. R software was used to generate PCoA plots.

Results

Bacterial 16S-rDNA gene sequences showed that the effective species annotative data were more than 97%. According to Ternary plot, Firmicutes and Bacteroidetes had similar abundance and contents among the 3 groups. Contents of Proteobacteria in RS1 were higher compared to RS2 and RS3. Bacterial genomic DNAs samples were clustered together in the same group; however, distances were relative far between different groups. RS1 illustrated significantly higher abundance of Proteobacteria colonies compared to healthy people (p<0.05), and illustrated higher abundance of Verrucomicrobia and lower abundance of Bacteroidetes and Firmicutes, but without significant differences (p>0.05).

Conclusions

Gut microbiome of PCS patients was dominated by Proteobacteria in feces and contained little Firmicutes and Bacteroidetes. The enhanced abundance of Proteobacteria might be the highly pathogenic risk factor for chronic abdominal pain and diarrhea in PCS patients.

Gut Microbial Dysbiosis in the Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Case-Control Studies

BACKGROUND

Irritable bowel syndrome (IBS) is the most common functional digestive condition in the industrialized world. The gut microbiota plays a key role in disease pathogenesis.

OBJECTIVE

A systematic review and meta-analysis on case-control studies was conducted to determine whether there is gut microbial dysbiosis in participants with IBS in comparison with healthy controls and, if so, whether the dysbiosis pattern differs among IBS subtypes and geographic regions.

METHODS

This review was conducted and reported according to the MOOSE (Meta-Analysis of Observational Studies in Epidemiology) 2000 and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2009 guidelines. Research articles published up to May 9, 2018 were identified through MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (Cochrane Library), ClinicalTrials.gov, EMBASE, and Web of Science. Study quality was assessed using the Newcastle-Ottawa Scale. Case-control studies of participants with IBS who had undergone quantitative gut microbial stool analysis were included. The primary exposure measure of interest is log₁₀ bacterial counts per gram of stool. Meta-analyses were performed to estimate the mean difference (MD) in gut microbiota between participants with IBS and healthy controls using the random-effects model with inverse variance in Revman 5.3 and R 3.5.1. Publication bias was assessed with funnel plots and Egger's test. Between-study heterogeneity was analyzed using Higgins I² statistic with 95% CIs.

RESULTS

There were 6,333 unique articles identified; 52 qualified for full-text screening. Of these, 23 studies were included for analysis (n=1,340 participants from North America, Europe, and Asia). Overall, the studies were moderate in quality. Comparing participants with IBS to healthy controls, lower fecal Lactobacillus (MD= -0.57 log₁₀ colony-forming unit [CFU]/g; P<0.01) and Bifidobacterium (MD= -1.04 log₁₀CFU/g; P<0.01), higher Escherichia coli (MD=0.60 log₁₀CFU/g; P<0.01), and marginally higher Enterobacter (MD=0.74 log₁₀CFU/g; P=0.05). No difference was found between participants with IBS and healthy controls in fecal Bacteroides and Enterococcus (P=0.18 and 0.68, respectively). Publication bias was not observed except in Bifidobacterium (P=0.015). Subgroup analyses on participants with diarrhea-predominant and constipation-predominant IBS showed consistent results with the primary results. A subgroup analysis of Chinese studies was consistent with the primary results, except for fecal Bacteroides, which was increased in participants with IBS vs healthy controls (MD=0.29; 95% CI 0.13 to 0.46; P<0.01). Although substantial heterogeneity was detected (I²>75%) in most comparisons, the direction of the effect estimates is relatively consistent across studies.

CONCLUSIONS

IBS is characterized by gut microbial dysbiosis. Prospective, large-scale studies are needed to delineate how gut microbial profiles can be used to guide targeted therapies in this challenging patient population.

The Microbiome and Irritable Bowel Syndrome - A Review on the Pathophysiology, Current Research and Future Therapy

Irritable bowel syndrome (IBS) is a functional disorder which affects a large proportion of the population globally. The precise etiology of IBS is still unknown, although consensus understanding proposes IBS to be of multifactorial origin with yet undefined subtypes. Genetic and epigenetic factors, stress-related nervous and endocrine systems, immune dysregulation and the brain-gut axis seem to be contributing factors that predispose individuals to IBS. In addition to food hypersensitivity, toxins and adverse life events, chronic infections and dysbiotic gut microbiota have been suggested to trigger IBS symptoms in tandem with the predisposing factors. This review will summarize the pathophysiology of IBS and the role of gut microbiota in relation to IBS. Current methodologies for microbiome studies in IBS such as genome sequencing, metagenomics, culturomics and animal models will be discussed. The myriad of therapy options such as immunoglobulins (immune-based therapy), probiotics and prebiotics, dietary modifications including FODMAP restriction diet and gluten-free diet, as well as fecal transplantation will be reviewed. Finally this review will highlight future directions in IBS therapy research, including identification of new molecular targets, application of 3-D gut model, gut-on-a-chip and personalized therapy.

Serum Bovine Immunoglobulins Improve Inflammation and Gut Barrier Function in Persons with HIV and Enteropathy on Suppressive ART

Background

Systemic inflammation persists in chronic HIV infection and is associated with increased rates of non-AIDS events such as cardiovascular and liver disease. Increased gut permeability and systemic exposure to microbial products are key drivers of this inflammation. Serum-derived bovine immunoglobulin/protein isolate (SBI) supports gut healing in other conditions such as inflammatory bowel disease.

Methods

In this randomized, double-blind study, participants receiving suppressive antiretroviral therapy (ART) with chronic diarrhea received placebo or SBI at 2.5 g BID or 5 g BID for 4 weeks, followed by a 20-week placebo-free extension phase with SBI at either 2.5 or 5 g BID. Intestinal fatty acid binding protein (I-FABP), zonulin, flagellin, lipopolysaccharide (LPS) and LPS-binding protein, and inflammatory markers were measured by ELISA or multiplex assays. Non-parametric tests were used for analysis.

Results

One hundred three participants completed the study. By week 24 SBI significantly decreased circulating levels of I-FABP (-0.35 ng/μL, P=0.002) and zonulin (-4.90 ng/μL, P=0.003), suggesting improvement in gut damage, and interleukin-6 (IL-6) (-0.40 pg/μL, P=0.002), reflecting improvement in systemic inflammation. In participants with the lowest quartile of CD4+ T-cell counts at baseline (189-418 cells/μL), CD4+ T-cell counts increased significantly (26 cells/μL; P=0.002).

Conclusions

Oral SBI may decrease inflammation and warrants further exploration as a potential strategy to improve gut integrity and decrease systemic inflammation among persons receiving prolonged suppressive ART.

Update on Pharmacotherapy for Irritable Bowel Syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a functional GI disorder that affects a large percentage of the population and presents a significant socio-economic burden on the society. In this article, we reviewed the evidence supporting various pharmacological treatment options for IBS.

RECENT FINDINGS

Rifaximin, eluxadoline, and alosetron have demonstrated that they reduce symptom severity improving quality of life in patients with IBS-diarrhea. Ramosetron is a promising agent in development. Peppermint oil has also demonstrated a positive impact on some symptoms of IBS. For IBS with constipation, traditional laxatives have failed to demonstrate significant benefit. However, lubiprostone, linaclotide, and plecanatide have demonstrated improvement of IBS with constipation in large, placebo-controlled trials. Tenapanor, a sodium/hydrogen exchanger 3 inhibitor, appears to be a promising treatment option in the pipeline. There are multiple pharmacologic agents with a variety of mechanisms that have demonstrated efficacy in IBS with diarrhea and constipation. There are no established pharmacologic agents for IBS with a mixed bowel pattern. There is a promising pipeline for additional novel therapies for IBS.

The Gut Microbiome in Adult and Pediatric Functional Gastrointestinal Disorders

The importance of gut microbiota in gastrointestinal (GI) physiology was well described, but our ability to study gut microbial ecosystems in their entirety was limited by culture-based methods prior to the sequencing revolution. The advent of high-throughput sequencing opened new avenues, allowing us to study gut microbial communities as an aggregate, independent of our ability to culture individual microbes. Early studies focused on association of changes in gut microbiota with different disease states, which was necessary to identify a potential role for microbes and generate novel hypotheses. Over the past few years the field has moved beyond associations to better understand the mechanistic implications of the microbiome in the pathophysiology of complex diseases. This movement also has resulted in a shift in our focus toward therapeutic strategies, which rely on better understanding the mediators of gut microbiota-host cross-talk. It is not surprising the gut microbiome has been implicated in the pathogenesis of functional gastrointestinal disorders given its role in modulating physiological processes such as immune development, GI motility and secretion, epithelial barrier integrity, and brain-gut communication. In this review, we focus on the current state of knowledge and future directions in microbiome research as it pertains to functional gastrointestinal disorders. We summarize the factors that help shape the gut microbiome in human beings. We discuss data from animal models and human studies to highlight existing paradigms regarding the mechanisms underlying microbiota-mediated alterations in physiological processes and their relevance in human interventions. While translation of microbiome science is still in its infancy, the outlook is optimistic and we are advancing in the right direction toward precise mechanism-based microbiota therapies.

Serum-derived bovine immunoglobulin for children with diarrhea-predominant irritable bowel syndrome

Background

Oral serum-derived bovine immunoglobulin (SBI)/protein isolate is a medical food intended to manage chronic diarrhea. It has been shown to improve pain and diarrhea in adults with diarrhea-predominant irritable bowel syndrome (d-IBS).

Aim

To determine if SBI can improve symptoms in children with d-IBS.

Methods

We performed a randomized, double-blind, placebo-controlled, pilot study (NCT02609529) to evaluate the effectiveness of SBI in children 8–18 years with d-IBS. We recorded stool number, abdominal pain, and stool form in all patients for 1 week and then assigned the patients at a ratio of 2:1 to treatment with SBI 5 g BID or placebo for 3 weeks. The patients and their parents completed the Pediatric Quality of Life Inventory™ for Gastrointestinal Symptoms (PedsQOL) and the Pediatric Functional Disability Index (FDI). In addition, complete blood counts and serum chemistries were recorded at the start and end of treatment to evaluate safety.

Results

Fifteen patients (nine SBI, six placebo) completed the study. Both SBI and placebo groups reported nonstatistical reductions in stool frequency per week. The SBI group showed a significant reduction in stool frequency at weeks 1 and 2 but not at the end of treatment. The SBI group also demonstrated statistical improvements in abdominal pain and stool form by 3 weeks. The placebo group did not achieve similar improvements. The overall FDI and PedsQOL scores, as well as PedsQOL subscale scores for pain, discomfort when eating, diarrhea, worry about stomach aches, and communication, improved significantly in the SBI group, but not in the placebo group. No serious adverse events occurred. Serum chemistries and hemograms were normal at baseline and at the end of study in all patients.

Conclusion

In this single-center, exploratory pilot study, we demonstrated that 10 g SBI per day was safe in children with d-IBS and improved symptoms. Larger studies, with longer treatment duration, seem warranted based on these initial positive results.

Existing and emerging therapies for managing constipation and diarrhea

Functional bowel disorders (i.e., constipation and diarrhea) are characterized by abdominal pain, bloating, distention, and/or bowel habit abnormalities in the absence of obvious anatomic or physiologic abnormalities on routine diagnostic tests. These symptoms are attributable to gastrointestinal sensorimotor dysfunctions resulting from peripheral and/or central mechanisms. Available drugs target the underlying bowel disturbance (i.e., constipation, diarrhea, or both), supplemented when necessary by management of pain. Osmotic and stimulant laxatives, secretagogues, and serotonin 5-HT4 receptor agonists are approved for treating constipation. Loperamide, anticholinergic agents, rifaximin, bile-acid binding agents, eluxadoline, and clonidine are used to treat diarrhea. Several exciting new compounds, some of which have been evaluated in humans, are currently under development.

Medicinal Foods for Functional GI Disorders

PURPOSE OF REVIEW

Over the past 10 years, there has been a dramatic increase in basic and clinical research involving functional gastrointestinal disorders (FGIDs). New diagnostic and biomarker procedures are helping to identify physiologic disruptions associated with FGIDs on cellular and molecular levels. Simultaneously, clinicians are using new approaches to help manage patients with FGIDs. Among these, an important component of care has been the use of medical foods. These include probiotics, prebiotics, synbiotics, peppermint oil, caraway oil, curcumin, bovine immunoglobulin and many others.

RECENT FINDINGS

The putative effects of different medical foods make these therapies attractive for the management of FGIDs. These include effects on several pathophysiological mechanisms such as anti-inflammatory, smooth muscle relaxation, analgesia, mitigation of gut barrier dysfunction, and stimulation or inhibition of gastrointestinal receptors. Recent research has also demonstrated the efficacy of medical food products such as peppermint oil and serum-derived bovine immunoglobulin for the management of irritable bowel syndrome. Older data supports the probiotic VSL#3 and Bifidobacterium species. For functional dyspepsia, positive effects have been observed with the combination of caraway seed oil and peppermint oil as well as with STW-5, a botanical combination preparation, although robust RCTs are lacking. With advancing knowledge regarding the pathogenesis of FGIDs, it is likely that the compounds available in the medical food category will increase dramatically, and they could play an important role in the management of several common and bothersome gastrointestinal conditions in the future.

Potential mechanisms of effects of serum-derived bovine immunoglobulin/protein isolate therapy in patients with diarrhea-predominant irritable bowel syndrome

Serum-derived bovine immunoglobulin/protein isolate (SBI), an oral nutritional therapy, is efficacious in diverse diarrheal diseases. In an open-label study in 15 patients with irritable bowel syndrome-diarrhea (IBS-D), we evaluated effects of SBI (5.0 g, twice a day) for 8 weeks on safety, on bowel function and abdominal pain, tryptophan metabolism (K:T ratio), intestinal permeability (13C-mannitol and lactulose excretion), bile acid synthesis (fasting serum FGF-19 and C4), duodenal and stool microbiome, and the expression of 90 genes related to inflammation, immune function, and tight junctions in duodenal mucosa. Statistical analysis (paired tests, baseline vs. treatment) was based on intention to treat (ITT) principles. One of 15 Caucasian patients (13F, 2M, age 40.3 ± 2.3y, BMI 34.3 ± 3.0 kg/m2) withdrew without completing studies. There were improvements in stools/day (decrease, P < 0.001), ease of passage (P = 0.035), and evacuation (P = 0.004) with SBI therapy. Worst pain severity was numerically reduced in last 2 weeks' treatment (P = 0.078). Duodenal mucosal mRNA expression; serum C4, FGF-19, and KT ratio; small bowel or colon permeability; and stool microbiome were not significantly different after SBI therapy, compared to baseline. In duodenal brushings, there was considerable microbiota structure difference (β diversity analysis P = 0.072, UniFrac) and, on taxonomic analysis, increased abundance of Proteobacteria Burkholderiales, Firmicutes Catonella, and unclassified genus organisms with SBI therapy. Thus, SBI therapy for 8 weeks in IBS-D patients is associated with improved bowel function; the mechanism of benefit is unclear, though there were microbiota structure differences in duodenal brushings. Further studies in patients with low-grade inflammation and intestinal barrier dysfunction at baseline are indicated.