[Intestinal microbiota in short bowel syndrome]

The Role of a Colon-in-Continuity in Short Bowel Syndrome

Short bowel syndrome (SBS) is a rare gastrointestinal condition that is defined as having less than 200 cm of remaining small intestine. SBS results from extensive surgical resection and is associated with a high risk for intestinal failure (IF) with a need for parenteral support (PS). Depending on the region of intestinal resection, three different main anatomy types can be distinguished from each other. In this review, we synthesize the current knowledge on the role of the colon in the setting of SBS-IF with a colon-in-continuity (SBS-IF-CiC), e.g., by enhancing the degree of intestinal adaptation, energy salvage, and the role of the microbiota. In addition, the effect of the disease-modifying treatment with glucagon-like peptide-2 (GLP-2) analogs in SBS-IF-CiC and how it differs from patients without a colon will be discussed. Overall, the findings explained in this review highlight the importance of preservation of the colon in SBS-IF.

Therapeutic potential of an intestinotrophic hormone, glucagon-like peptide 2, for treatment of type 2 short bowel syndrome rats with intestinal bacterial and fungal dysbiosis

Background

Previous studies showed that type 2 short bowel syndrome (SBS) rats were accompanied by severe intestinal bacterial dysbiosis. Limited data are available for intestinal fungal dysbiosis. Moreover, no effective therapeutic drugs are available for these microbiota dysbiosis. The aims of our study were to investigate the therapeutic potential of glucagon-like peptide 2 (GLP-2) for these microbiota dysbiosis in type 2 SBS rats.

Methods

8-week-old male SD rats which underwent 80% small bowel resection, ileocecum resection, partial colon resection and jejunocolostomy, were treated with saline (SBS group, n = 5) or GLP-2 (GLP2.SBS group, n = 5). The Sham group rats which underwent transection and re-anastomosis were given a saline placebo (Sham group, n = 5). 16S rRNA and ITS sequencing were applied to evaluate the colonic bacterial and fungal composition at 22 days after surgery, respectively.

Results

The relative abundance of Actinobacteria, Firmicutes and proinflammatory Proteobacteria increased significantly in SBS group rats, while the relative abundance of Bacteroidetes, Verrucomicrobia and Tenericutes decreased remarkably. GLP-2 treatment significantly decreased Proteus and increased Clostridium relative to the saline treated SBS rats. The diversity of intestinal fungi was significantly increased in SBS rats, accompanied with some fungi abnormally increased and some resident fungi (e.g., Penicillium) significantly decreased. GLP-2 treatment significantly decreased Debaryomyces and Meyerozyma, and increased Penicillium. Moreover, GLP-2 partially restored the bacteria-fungi interkingdom interaction network of SBS rats.

Conclusion

Our study confirms the bacterial and fungal dysbiosis in type 2 SBS rats, and GLP-2 partially ameliorated these microbiota dysbiosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06270-w.

The colon as an energy salvage organ for children with short bowel syndrome

BACKGROUND

The main cause of intestinal failure is short bowel syndrome (SBS). The management goal for children with SBS is to promote intestinal adaptation while preserving growth and development with the use of parenteral nutrition (PN).

OBJECTIVES

This study evaluated the intestinal absorption rate in children with SBS, focusing on the role of the remnant colon. In addition, the relation between intestinal absorption rate, citrulline concentration, and small bowel length was studied.

METHODS

Thirty-two children with SBS on PN were included. They were divided into 3 groups according to the European Society for Clinical Nutrition and Metabolism (ESPEN) anatomical classification system: type 1 SBS (n = 9), type 2 (n = 13), and type 3 (n = 10). Intestinal absorption rate was assessed by a stool balance analysis of a 3-d collection of stools. Plasma citrulline concentrations were measured and the level of PN dependency was calculated.

RESULTS

The total energy absorption rate did not differ significantly between the 3 groups: 68% (61-79% ) for type 1, 60% (40-77%) for type 2, and 60% (40-77%) for type 3 ( P = 0.45). Children with type 2 or 3 SBS had significantly shorter small bowel length than children with type 1: 28 cm (19-36 cm) and 16 cm (2-29 cm), respectively, compared with 60 cm (45-78 cm) ( P = 0.04). Plasma citrulline concentrations were lower in type 3 SBS but not significantly different: 15 µmol/L (11-25 µmol/L) in type 1, 14 µmol/L (7-21 µmol/L) in type 2 , and 9 µmol/L (6-14 µmol/L) in type 3 ( P = 0.141). A multivariate analysis confirmed the role of the remnant colon in providing additional energy absorption.

CONCLUSION

This study demonstrated the importance of the colon as a salvage organ in children with SBS. Plasma citrulline concentrations should be interpreted according to the type of SBS. Efforts should focus on conservative surgery, early re-establishment of a colon in continuity, and preserving the intestinal microbiota.

Bacteria, Bones, and Stones: Managing Complications of Short Bowel Syndrome

Short bowel syndrome (SBS) occurs in patients who have had extensive resection. The primary physiologic consequence is malabsorption, resulting in fluid and electrolyte abnormalities and malnutrition. Nutrient digestion, absorption, and assimilation may also be diminished by disturbances in the production of bile acids and digestive enzymes. Small bowel dilation, dysmotility, loss of ileocecal valve, and anatomical changes combined with acid suppression and antimotility drugs increase the risk of small intestinal bacterial overgrowth, further contributing to malabsorption. Metabolic changes that occur in SBS due to loss of colonic regulation of gastric and small bowel function can also lead to depletion of calcium, magnesium, and vitamin D, resulting in demineralization of bone and the eventual development of bone disease. Persistent inflammation, steroid use, parenteral nutrition, chronic metabolic acidosis, and renal insufficiency may exacerbate the problem and contribute to the development of osteoporosis. Multiple factors increase the risk of nephrolithiasis in SBS. In the setting of fat malabsorption, increased free fatty acids are available to bind to calcium, resulting in an increased concentration of unbound oxalate, which is readily absorbed across the colonic mucosa where it travels to the kidney. In addition, there is an increase in colonic permeability to oxalate stemming from the effects of unabsorbed bile salts. The risk of nephrolithiasis is compounded by volume depletion, metabolic acidosis, and hypomagnesemia, resulting in a decrease in renal perfusion, urine output, pH, and citrate excretion. This review examines the causes and treatments of small intestinal bacterial overgrowth, bone demineralization, and nephrolithiasis in SBS.

Intestinal barrier regulates immune responses in the liver via IL-10-producing macrophages

The gut-liver axis is of clinical importance as a potential therapeutic target in a wide range of liver diseases; however, the mechanisms underlying interactions between microbial products and immune responses in the liver remain unknown. In this study, we demonstrated that IL-10-producing macrophages contribute to immune tolerance in the inflamed liver under intestinal barrier disruption in a murine tandem model of dextran sulfate sodium (DSS) colitis and concanavalin A (Con A) hepatitis. Intestinal barrier disruption protected mice from subsequent liver injury, and the severity of colitis directly affected susceptibility to such injury. The protective effect of DSS-Con A was canceled in gut-sterilized mice, suggesting that gut microbiota play a substantial role in this process. Altered gut microbiota and their metabolites, along with a disrupted intestinal barrier, directly gave rise to immunological permissiveness in the inflamed liver. We identified 1-methylnicotinamide (1-MNA) as a candidate metabolite capable of suppressing liver injury with the potential to induce IL-10-producing macrophages. Consistently, expression of nicotinamide N-methyltransferase, which converts nicotinamide to 1-MNA, was upregulated in the liver of DSS-Con A mice, and this effect was abrogated by gut sterilization. Collectively, our results provide a mechanistic insight into the regulation of immunological balance in the liver via the gut-liver axis.

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy

The pathogenesis of irritable bowel syndrome (IBS), once thought to be largely psychogenic in origin, is now understood to be multifactorial. One of the reasons for this paradigm shift is the realization that gut dysbiosis, including small intestinal bacterial overgrowth (SIBO), causes IBS symptoms. Between 4% and 78% of patients with IBS and 1% and 40% of controls have SIBO; such wide variations in prevalence might result from population differences, IBS diagnostic criteria, and, most importantly, methods to diagnose SIBO. Although quantitative jejunal aspirate culture is considered the gold standard for the diagnosis of SIBO, noninvasive hydrogen breath tests have been popular. Although the glucose hydrogen breath test is highly specific, its sensitivity is low; in contrast, the early-peak criteria in the lactulose hydrogen breath test are highly nonspecific. Female gender, older age, diarrhea-predominant IBS, bloating and flatulence, proton pump inhibitor and narcotic intake, and low hemoglobin are associated with SIBO among IBS patients. Several therapeutic trials targeting gut microbes using antibiotics and probiotics have further demonstrated that not all symptoms in patients with IBS originate in the brain but rather in the gut, providing support for the micro-organic basis of IBS. A recent proof-of-concept study showing the high frequency of symptom improvement in patients with IBS with SIBO further supports this hypothesis.

Alterations in intestinal microbiota relate to intestinal failure-associated liver disease and central line infections

BACKGROUND

The gut microbiota plays a vital role in modulating the metabolic and immune functions of the intestines. We aimed to analyze the dysbiosis of microbiota in infants with short bowel syndrome (SBS) with different complications.

PROCEDURE

We included 26 fecal samples from 18 infants with SBS during parenteral nutrition. The samples were categorized into three groups: asymptomatic, parenteral nutrition-associated liver disease (PNALD), and central line-associated bloodstream infection (CLABSI). Seven healthy infants were enrolled as controls. Fecal microbiota, secretory IgA, calprotectin, bile acids, and short chain fatty acids were detected.

RESULTS

The bacterial diversity of the Asymptomatic and Control Groups was significantly higher than that in the PNALD and CLABSI Groups. Proteobacteria was the most pronounced phylum in the PNALD and CLABSI Groups. Decreased acetate was observed in all SBS samples; however, fecal secretory IgA and calprotectin and the proportion of primary and secondary bile acids did not differ from those in healthy controls.

CONCLUSIONS

Marked alterations of the intestinal microbiota with decreased level of acetate were shown in SBS patients compared with healthy controls. Over-abundance of Proteobacteria (especially Enterobacteriaceae) was found in the samples from the PNALD and CLABSI Groups.

LEVEL OF EVIDENCE

Prognosis Study, Level I.

Pediatric intestinal failure-associated liver disease

PURPOSE OF REVIEW

The goal of this review is to provide updates on the definition, pathophysiology, treatment, and prevention of intestinal failure-associated liver disease (IFALD) that are relevant to care of pediatric patients.

RECENT FINDINGS

Current literature emphasizes the multifactorial nature of IFALD. The pathogenesis is still largely unknown; however, molecular pathways have been identified. Key to these pathways are proinflammatory cytokines involved in hepatic inflammation and bile acids synthesis such as Toll-like receptor 4 and farnesoid X receptor, respectively. Research for prevention and treatment is aimed at alleviating risk factors associated with IFALD, principally those associated with parental nutrition. Multiple nutrients and amino acids are relevant to the development of IFALD, but lipid composition has been the primary focus. Lipid emulsions with a lower ratio of omega-6-to-omega-3 polyunsaturated fatty acids (FAs) appear to improve bile flow and decrease intrahepatic inflammation. Long-term consequences of these alternative lipid emulsions are yet to be determined.

SUMMARY

IFALD remains the greatest contributor of mortality in patients with intestinal failure. Many factors contribute to its development, namely, alterations in the gut microbiome, sepsis, and lack of enteral intake. Novel combinations of lipid formulations are promising alternatives to purely soy-based formulas to reduce cholestasis.

Redefining short bowel syndrome in the 21st century

In 1968, Wilmore and Dudrick reported an infant sustained by parenteral nutrition (PN) providing a potential for survival for children with significant intestinal resections. Increasing usage of TPN over time led to some patients developing Intestinal Failure Associated Liver Disease (IFALD), a leading cause of death and indication for liver/intestinal transplant. Over time, multidisciplinary teams called Intestinal Rehabilitation Programs (IRPs) began providing meticulous and innovative management. Usage of alternative lipid emulsions and lipid minimization strategies have resulted in the decline of IFALD and an increase in long-term and transplant-free survival, even in the setting of ultrashort bowel (< 20 cm). Autologous bowel reconstructive surgeries, such as the serial tapering enteroplasty procedure, have increased the likelihood of achieving enteral autonomy. Since 2007, the number of pediatric intestinal transplants performed has sharply declined and likely attributed to the newer innovations healthcare. Recent data support the need for changes in the listing criteria for intestinal transplantation given the overall improvement in outcomes. Over the last 50 y, the diagnosis of short bowel syndrome has changed from a death sentence to one of hope with a vast improvement of quality of life and survival.

Is it bowel-associated dermatosis-arthritis syndrome induced by small intestinal bacteria overgrowth?

Introduction

Bowel-associated dermatosis-arthritis syndrome is rare systemic diseases characterized by a prodrome of fever, chills, and influenza-like symptoms with subsequent skin eruptions, myalgias, and polyarthralgias. It is reported to be occurred in Intestinal bypass surgery and inflammatory bowel disease.

Case description

Herein, we described a 29-years-old man with Bowel-associated dermatosis-arthritis syndrome. He had no history of gastrointestinal surgery and inflammatory bowel disease. Distribution of the gut bacterial flora showed small intestinal bacterial overgrowth.

Discussion and Evaluation

It is rarely form as Non-intestinal bypass road and non-inflammatory bowel disease was induced by small intestinal bacteria overgrowth.

Conclusions

We concluded that Immuno-inflammatory response to overgrowth of intestinal bacterial antigen induce the clinical symptoms of bowel-associated dermatosis-arthritis syndrome.

Intestinal Failure: Adaptation, Rehabilitation, and Transplantation

Intestinal failure (IF) is a state in which the nutritional demands are not met by the gastrointestinal absorptive surface. A majority of IF cases are associated with short-bowel syndrome, which is a result of malabsorption after significant intestinal resection for numerous reasons, some of which include Crohn's disease, vascular thrombosis, and radiation enteritis. IF can also be caused by obstruction, dysmotility, and congenital defects. Recognition and management of IF can be challenging, given the complex nature of this condition. This review discusses the management of IF with a focus on intestinal rehabilitation, parenteral nutrition, and transplantation.

Extensive Intestinal Resection Triggers Behavioral Adaptation, Intestinal Remodeling and Microbiota Transition in Short Bowel Syndrome

Extensive resection of small bowel often leads to short bowel syndrome (SBS). SBS patients develop clinical mal-absorption and dehydration relative to the reduction of absorptive area, acceleration of gastrointestinal transit time and modifications of the gastrointestinal intra-luminal environment. As a consequence of severe mal-absorption, patients require parenteral nutrition (PN). In adults, the overall adaptation following intestinal resection includes spontaneous and complex compensatory processes such as hyperphagia, mucosal remodeling of the remaining part of the intestine and major modifications of the microbiota. SBS patients, with colon in continuity, harbor a specific fecal microbiota that we called “lactobiota” because it is enriched in the Lactobacillus/Leuconostoc group and depleted in anaerobic micro-organisms (especially Clostridium and Bacteroides). In some patients, the lactobiota-driven fermentative activities lead to an accumulation of fecal d/l-lactates and an increased risk of d-encephalopathy. Better knowledge of clinical parameters and lactobiota characteristics has made it possible to stratify patients and define group at risk for d-encephalopathy crises.

Intestinal dysbiosis in children with short bowel syndrome is associated with impaired outcome

BACKGROUND

The composition of the intestinal microbiota seems to be an important factor in determining the clinical outcome in children with short bowel syndrome (SBS). Alterations in the microbiota may result in serious complications such as small bowel bacterial overgrowth (SBBO) and intestinal mucosal inflammation that lead to prolonged parenteral nutrition (PN) dependency with subsequently increased risk of liver failure and sepsis. To date, there are no reported mappings of the intestinal microbiome in children with SBS. Here, we present the first report on the intestinal microbial community profile in children with SBS.

FINDINGS

The study includes children diagnosed with SBS in the neonatal period. Healthy siblings served as controls. Fecal samples were collected, and microbial profiles were analyzed by using 16S rRNA gene sequencing on the Illumina MiSeq platform. We observed a pronounced microbial dysbiosis in children with SBS on PN treatment with an increased and totally dominating relative abundance of Enterobacteriacae in four out of five children compared to children with SBS weaned from PN and healthy siblings.

CONCLUSIONS

The overall decreased bacterial diversity in children with SBS is consistent with intestinal microbiome mappings in inflammatory bowel diseases such as Crohn's disease and necrotizing enterocolitis in preterm infants. Our findings indicate that intestinal dysbiosis in children with SBS is associated with prolonged PN dependency.

Current views on the etiopathogenesis, clinical manifestation, diagnostics, treatment and correlation with other nosological entities of SIBO

Small intestinal bacterial overgrowth (SIBO) is a disease of great clinical and socioeconomic importance caused by an excessive amount of bacteria in the upper alimentary tract. Physiological microbiota are replaced by pathogenic bacteria mainly from large intestine, which is called dysbacteriosis. SIBO disturbs digestion and absorption in the alimentary tract, which seems to cause inflammation. SIBO affects the morphology and function of the digestive system and causes systemic complications (e.g. osteoporosis, macrocytic anemia). Inflammation interferes with gene expression responsible for producing and secreting mucus, therefore, a correlation between SIBO and cystic fibrosis, irritable bowel syndrome and chronic abdominal pain are postulated. All conditions leading to bacterial growth such as congenital and anatomical abnormalities in the digestive tract, motility disorder or immunological deficits are risk factors of SIBO. A typical clinical manifestation of SIBO comprises meteorism, enterectasia, abdominal discomfort and diarrhea. Diagnostic procedures such as glucose, lactulose, methane, 13C mixed triglyceride breath tests are being used in diagnosing SIBO.

Effects of 12 weeks of probiotic supplementation on quality of life in colorectal cancer survivors: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Probiotics may help resolve bowel symptoms and improve quality of life. We investigated the effects of 12 weeks of probiotics administration in colorectal cancer patients.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial. The participants took probiotics (Lacidofil) or placebo twice a day for 12 weeks. The cancer-related quality of life (FACT), patient's health-9 (PHQ-9), and bowel symptom questionnaires were completed by each participant.

RESULTS

We obtained data for 32 participants in the placebo group and 28 participants in the probiotics group. The mean ages of total participants were 56.18 ± .86 years and 58.3% were male. Administration of probiotics significantly decreased the proportion of patients suffering from irritable bowel symptoms (0 week vs. 12 week; 67.9% vs. 45.7%, p=0.03), improved colorectal cancer-related FACT (baseline vs. 12 weeks: 19.79 ± 4.66 vs. 21.18 ± 3.67, p=0.04) and fatigue-related FACT (baseline vs. 12 weeks: 43.00 (36.50-45.50) vs. 44.50 (38.50-49.00), p=0.02) and PHQ-9 scores (0 weeks vs. 12 weeks; 3.00 (0-8.00) vs. 1.00 (0-3.00), p=0.01). We found significant differences in changes of the proportion of patients with bowel symptoms (p<0.05), functional well-being scores (p=0.04) and cancer-related FACT scores (p=0.04) between the two groups.

CONCLUSION

Probiotics improved bowel symptoms and quality of life in colorectal cancer survivors.

Gut microbial diversity is reduced and is associated with colonic inflammation in a piglet model of short bowel syndrome

BACKGROUND AND OBJECTIVES

Following small bowel resection (SBR), the luminal environment is altered, which contributes to clinical manifestations of short bowel syndrome (SBS) including malabsorption, mucosal inflammation and bacterial overgrowth. However, the impact of SBR on the colon has not been well-defined. The aims of this study were to characterize the colonic microbiota following SBR and to assess the impact of SBR on mucosal inflammation in the colon.

RESULTS

Analysis of the colonic microbiota demonstrated that there was a significant level of dysbiosis both two and six weeks post-SBR, particularly in the phylum Firmicutes, coupled with a decrease in overall bacterial diversity in the colon. This decrease in diversity was associated with an increase in colonic inflammation six weeks post-surgery.

METHODS

Female (4-week old) piglets (5-6/group) received a 75% SBR, a transection (sham) or no surgery. Compositional analysis of the colonic microbiota was performed by high-throughput sequencing, two- and six-weeks post-surgery. The gene expression of the pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-8, IL-18 and tumor necrosis factor (TNF)-α in the colonic mucosa was assessed by qRT-PCR and the number of macrophages and percentage inducible nitric oxide synthase (iNOS) staining in the colonic epithelium were quantified by immunohistochemistry.

CONCLUSIONS

SBR significantly decreased the diversity of the colonic microbiota and this was associated with an increase in colonic mucosal inflammation. This study supports the hypothesis that SBR has a significant impact on the colon and that this may play an important role in defining clinical outcome.

Cystic fibrosis transmembrane conductance regulator knockout mice exhibit aberrant gastrointestinal microbiota

The composition of the gastrointestinal microbiome is increasingly recognized as a crucial contributor to immune and metabolic homeostasis-deficiencies in which are characteristic of cystic fibrosis (CF) patients. The murine model (CFTR (-/-) , CF), has, in previous studies, demonstrated characteristic CF gastrointestinal (GI) manifestations including slowed transit and significant upregulation of genes associated with inflammation. To determine if characteristics of the microbiome are associated with these phenotypes we used a phylogenetic microarray to compare small intestine bacterial communities of wild type and congenic CF mice. Loss of functional CFTR is associated with significant decreases in GI bacterial community richness, evenness and diversity and reduced relative abundance of putative protective species such as Acinetobacter lwoffii and a multitude of Lactobacilliales members. CF mice exhibited significant enrichment of Mycobacteria species and Bacteroides fragilis, previously associated with GI infection and immunomodulation. Antibiotic administration to WT and CF animals resulted in convergence of their microbiome composition and significant increases in community diversity in CF mice. These communities were characterized by enrichment of members of the Lactobacillaceae and Bifidobacteriaceae and reduced abundance of Enterobacteriaceae and Clostridiaceae. These data suggest that Enterobacteria and Clostridia species, long associated with small intestinal overgrowth and inflammatory bowel disease, may suppress both ileal bacterial diversity and the particular species which maintain motility and immune homeostasis in this niche. Thus, these data provide the first indications that GI bacterial colonization is strongly impacted by the loss of functional CFTR and opens up avenues for alternative therapeutic approaches to improve CF disease management.