Enteric microbial flora, bacterial overgrowth, and short-bowel syndrome

Host control and species interactions jointly determine microbiome community structure

The host microbiome can be considered an ecological community of microbes present inside a complex and dynamic host environment. The host is under selective pressure to ensure that its microbiome remains beneficial. The host can impose a range of ecological filters including the immune response that can influence the assembly and composition of the microbial community. How the host immune response interacts with the within-microbiome community dynamics to affect the assembly of the microbiome has been largely unexplored. We present here a mathematical framework to elucidate the role of host immune response and its interaction with the balance of ecological interactions types within the microbiome community. We find that highly mutualistic microbial communities characteristic of high community density are most susceptible to changes in immune control and become invasion prone as host immune control strength is increased. Whereas highly competitive communities remain relatively stable in resisting invasion to changing host immune control. Our model reveals that the host immune control can interact in unexpected ways with a microbial community depending on the prevalent ecological interactions types for that community. We stress the need to incorporate the role of host-control mechanisms to better understand microbiome community assembly and stability.

Prevalence of small intestinal bacterial overgrowth in intestinal failure syndrome: A systematic review and meta-analysis

BACKGROUND AND AIM

Patients with intestinal failure (IF) have abnormal intestinal anatomy, secretion, and dysmotility, which impairs intestinal homeostatic mechanisms and may lead to small intestinal bacterial overgrowth (SIBO). We conducted a systematic review and meta-analysis to determine the prevalence of SIBO in patients with IF and to identify risk factors for SIBO.

METHODS

MEDLINE (PubMed) and Embase electronic databases were searched from inception to December 2023 for studies that reported the prevalence of SIBO in IF. The prevalence rates, odds ratio (OR), and 95% confidence intervals of SIBO in IF and the risk factors for SIBO in IF were calculated using random effects model.

RESULTS

Final dataset included nine studies reporting on 407 patients with IF. The prevalence of SIBO in IF was 57.5% (95% CI 44.6-69.4), with substantial heterogeneity in this analysis (I2 = 80.9, P = 0.0001). SIBO prevalence was sixfold higher in patients with IF who received parenteral nutrition (PN) compared with IF patients not on PN (OR = 6.0, 95% CI 3.0-11.9, P = 0.0001). Overall, the prevalence of SIBO in patients with IF using PPI/acid-suppressing agents (72.0%, 95% CI 57.5-83.8) was numerically higher compared with IF patients not using these agents (47.6%, 95% CI 25.7-70.2).

CONCLUSIONS

This systematic review and meta-analysis suggests that there is an increased risk of SIBO in patients with IF and that PN, and potentially, the use of PPI/acid-suppressing agents is risk factors for SIBO development in patients with IF. However, the quality of evidence is low and can be attributed to lack of case-control studies and clinical heterogeneity seen in the studies.

Risk Factors for Infection in Neonates With Intestinal Failure

PURPOSE

Neonates with intestinal failure (IF) are at risk for infection due to central venous access, and intestinal surgery. Infection can cause systemic inflammation and sepsis, potentially affecting growth. The purpose of this study was to identify risk factors for, and the potential impact of infection to help with preventative strategies.

METHODS

A retrospective review of infants with IF, at a single centre from 2018 to 2022 was conducted. Clinical characteristics, intestinal pathology, nutritional intake, and growth were compared among infants with bloodstream infection (BSI), other infection (OI) (urinary, respiratory, or wound), or no infection (NI) within 2 months of diagnosis. Mann-Whitney and Kruskal-Wallis tests were used for comparisons with p-values <0.05 considered significant.

RESULTS

Eighty-six infants were included, with gastroschisis (41%) and necrotizing enterocolitis (26%) the most common diagnoses. Fifty-nine % of infants developed infection (22% BSI and 37% OI). Those with BSI or OI had a lower gestational age and birthweight, and were more likely to have a stoma. All infants with complex gastroschisis developed infection compared to 38% of infants with simple gastroschisis. Median daily weight gain was suboptimal across all groups and did not differ over 6 weeks following infection.

CONCLUSION

Most infants with IF develop infection shortly after diagnosis. Risk factors include prematurity, complex gastroschisis, and the presence of a stoma. Growth was suboptimal but did not differ among infants with or without infection.

TYPE OF STUDY

Retrospective Review.

LEVEL OF EVIDENCE

Level III Retrospective Comparative Study.

Fat malabsorption in short bowel syndrome: A review of pathophysiology and management

Fat malabsorption is central to the pathophysiology of short bowel syndrome (SBS). It occurs in patients with insufficient intestinal surface area and/or function to maintain metabolic and growth demands. Rapid intestinal transit and impaired bile acid recycling further contribute to fat malabsorption. A significant portion of patients require parenteral nutrition (PN) for their survival but may develop sepsis and liver dysfunction as a result. Despite advancements in the treatment of SBS, fat malabsorption remains a chronic issue for this vulnerable patient population. Peer-reviewed literature was assessed on the topic of fat malabsorption in SBS. Current management of patients with SBS involves dietary considerations, PN management, antidiarrheals, glucagon-like peptide 2 agonists, and multidisciplinary teams. Clinical trials have focused on improving intestinal fat absorption by facilitating fat digestion with pancreatic enzymes. Targeting fat malabsorption in SBS is a potential pathway to improving lifestyle and reducing morbidity and mortality in this rare disease.

Cutoffs and Characteristics of Abnormal Bowel Dilatation in Pediatric Short Bowel Syndrome

OBJECTIVES

Although excessive intestinal dilatation associates with worsened outcomes in pediatric short bowel syndrome (SBS), little is known about the natural history and definition of pathological dilatation. We addressed fore-, mid-, and hind-gut dilatation in children with SBS, who had not undergone autologous intestinal reconstructive (AIR) surgery, in relation to controls.

METHODS

SBS children without history of AIR surgery (n = 59) and age-matched controls without any disclosed intestinal pathology (n = 140) were included. Maximum diameter of duodenum, small bowel (SB), and colon were measured in each intestinal contrast series during 2002 to 2020 and expressed as diameter ratio (DR) to L5 vertebrae height. Predictive ability of DR for weaning off parenteral nutrition (PN) was analyzed with Cox proportional hazards regression models using multiple cutoffs.

RESULTS

Duodenum (DDR), SB (SBDR), and colon (CDR) DR were 53%, 183%, and 23% higher in SBS patients compared to controls ( P < 0.01 for all). The maximal DDR and SBDR measured during follow-up is associated with current PN dependence and young age. DDR correlated with SBDR ( r = 0.586, P < 0.01). Patients with maximal DDR less than 1.5, which was also the 99th percentile for controls, were 2.5-fold more likely to wean off PN ( P = 0.005), whereas SBDR and CDR were not predictive for PN duration.

CONCLUSIONS

All segments of remaining bowel, especially SB, dilate above normal levels in children with SBS. In SBS children without AIR surgery, PN dependence and young age is associated with duodenal and small intestinal dilatation, while duodenal dilatation also predicted prolonged PN.

ESPEN guideline on chronic intestinal failure in adults - Update 2023

BACKGROUND & AIMS

In 2016, ESPEN published the guideline for Chronic Intestinal Failure (CIF) in adults. An updated version of ESPEN guidelines on CIF due to benign disease in adults was devised in order to incorporate new evidence since the publication of the previous ESPEN guidelines.

METHODS

The grading system of the Scottish Intercollegiate Guidelines Network (SIGN) was used to grade the literature. Recommendations were graded according to the levels of evidence available as A (strong), B (conditional), 0 (weak) and Good practice points (GPP). The recommendations of the 2016 guideline (graded using the GRADE system) which were still valid, because no studies supporting an update were retrieved, were reworded and re-graded accordingly.

RESULTS

The recommendations of the 2016 guideline were reviewed, particularly focusing on definitions, and new chapters were included to devise recommendations on IF centers, chronic enterocutaneous fistulas, costs of IF, caring for CIF patients during pregnancy, transition of patients from pediatric to adult centers. The new guideline consist of 149 recommendations and 16 statements which were voted for consensus by ESPEN members, online in July 2022 and at conference during the annual Congress in September 2022. The Grade of recommendation is GPP for 96 (64.4%) of the recommendations, 0 for 29 (19.5%), B for 19 (12.7%), and A for only five (3.4%). The grade of consensus is "strong consensus" for 148 (99.3%) and "consensus" for one (0.7%) recommendation. The grade of consensus for the statements is "strong consensus" for 14 (87.5%) and "consensus" for two (12.5%).

CONCLUSIONS

It is confirmed that CIF management requires complex technologies, multidisciplinary and multiprofessional activity, and expertise to care for the underlying gastrointestinal disease and to provide HPN support. Most of the recommendations were graded as GPP, but almost all received a strong consensus.

Short bowel syndrome: Complications and management

Short bowel syndrome (SBS) occurs when a patient loses bowel length or function significantly enough to cause malabsorption, oftentimes requiring lifelong parenteral support. In adults, this occurs most commonly in the setting of massive intestinal resection, whereas congenital anomalies and necrotizing enterocolitis predominate in children. Many patients with SBS develop long-term clinical complications over time related to their altered intestinal anatomy and physiology or to various treatment interventions such as parenteral nutrition and the central venous catheter through which it is administered. Identifying, preventing, and treating these complications can be challenging. This review will focus on the diagnosis, treatment, and prevention of several complications that can occur in this patient population, including diarrhea, fluid and electrolyte imbalance, vitamin and trace element derangements, metabolic bone disease, biliary disorders, small intestinal bacterial overgrowth, d-lactic acidosis, and complications of central venous catheters.

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.

Glucagon-like peptide-2 analogues for Crohn’s disease patients with short bowel syndrome and intestinal failure

Short bowel syndrome (SBS) with intestinal failure (IF) is a rare but severe complication of Crohn’s disease (CD), which is the most frequent benign condition that leads to SBS after repeated surgical resections, even in the era of biologics and small molecules. Glucagon-like peptide-2 analogues have been deeply studied recently for the treatment of SBS-IF. These drugs have a significant intestinotrophic effect and the potential to reduce the chronic dependence of SBS-IF patients on parenteral support or nutrition. Teduglutide has been approved for the treatment of SBS-IF, and apraglutide is currently in clinical development. The use of these drugs was examined with a focus on their use in CD patients.

Surgical Treatment of Short Bowel Syndrome—The Past, the Present and the Future, a Descriptive Review of the Literature

Short bowel syndrome (SBS) is a devastating disorder with both short- and long-term implications for patients. Unfortunately, the prevalence of SBS has doubled over the past 40 years. Broadly speaking, the etiology of SBS can be categorized as congenital or secondary, the latter typically due to extensive small bowel resection following diseases of the small intestine, e.g., necrotizing enterocolitis, Hirschsprung’s disease or intestinal atresia. As of yet, no cure exists, thus, conservative treatment, primarily parenteral nutrition (PN), is the first-line therapy. In some cases, weaning from PN is not possible and operative therapy is required. The invention of the longitudinal intestinal lengthening and tailoring (LILT or Bianchi) procedure in 1980 was a major step forward in patient care and spawned further techniques that continue to improve lives for patients with severe SBS (e.g., double barrel enteroplasty, serial transverse enteroplasty, etc.). With this review, we aim to provide an overview of the clinical implications of SBS, common conservative therapies and the development of operative techniques over the past six decades. We also provide a short outlook on the future of operative techniques, specifically with respect to regenerative medicine.

Short Bowel Syndrome in Adults

Short bowel syndrome (SBS) is a rare disorder characterized by severe intestinal dysfunction leading to malabsorption of macronutrients and micronutrients that often results in permanent need of parenteral nutrition support. Patients can develop SBS because of massive intestinal resection or loss of intestinal function and consequently experience significant morbidity and increased healthcare utilization. The remaining anatomy and length of bowel after intestinal resection have important prognostic and therapeutic implications. Because patients with SBS constitute a heterogenous group, management is complex and multifaceted, involving nutrition support, fluid and electrolyte management, and pharmacologic therapies in particular to control diarrhea. Surgical interventions including intestinal transplantation may be considered in selected individuals. Successful care of these patients is best accomplished by a multidisciplinary team that is experienced in the management of this syndrome.

Probiotic Treatment Versus Empiric Oral Antibiotics for Managing Dysbiosis in Short Bowel Syndrome: Impact on the Mucosal and Stool Microbiota, Short Chain Fatty Acids and Adaptation

BACKGROUND

Infants and children with short bowel syndrome (SBS) are presumed to be at risk of gut microbial dysbiosis with potential sequelae of bacterial overgrowth that include sepsis, D-lactic acidosis, mucosal inflammation and malabsorption. In neonatal piglets with SBS, we compared intestinal microbial composition, short chain fatty acids (SCFA) and adaptation given probiotic treatment (Lactobacillus and Bifidobacterium spp.) versus oral metronidazole.

METHODS

Following 75% distal small intestinal resection, piglets were allocated to: probiotic (PRO, 500mg BID n=7), metronidazole (MET, 15mg/kg BID n=8) and placebo (PLA, 500mg BID n=8). After 10 days of parenteral and enteral nutrition, 16S rRNA gene amplicon sequencing (colon tissue and stool) were undertaken and SCFA analysis (stool and colon effluent) performed using gas chromatography.

RESULTS

In colon, Shannon diversity was higher for PRO compared to MET and PLA (p=0.002). PRO and PLA increased abundance of Bacteroidetes species (e.g. Bacteroides fragilis), compared to MET (p<0.001). PRO compared to PLA increased abundance of Firmicutes species (e.g. Lactobacillus fermentum) (p<0.001). MET increased abundance of Proteobacteria members, predominately Enterobacteriaceae compared to PRO (p=0.004). In stool, microbial findings were similar and SCFA (butyrate) concentrations were highest for PRO (p=0.003) compared to MET.

CONCLUSION

In pediatric SBS, the empiric use of oral antibiotics, such as metronidazole, is common for presumed clinical consequences of microbial dysbiosis. In this study of SBS piglets, that approach was associated with decreased microbial diversity and increased abundance of potentially inflammatory Proteobacteria. In contrast, a probiotic treatment using Lactobacillus and Bifidobacterium spp. increased both diversity and SCFAs. This article is protected by copyright. All rights reserved.

Jejunoileal mucosal growth in mice with a limited microbiome

Previous work demonstrated enhanced enterocyte proliferation and mucosal growth in gnotobiotic mice, suggesting that intestinal flora participate in mucosal homeostasis. Furthermore, broad-spectrum enteral antibiotics are known to induce near germ-free (GF) conditions in mice with conventional flora (CONV). We hypothesized that inducing near GF conditions with broad-spectrum enteral antibiotics would cause ordered small intestinal mucosal growth in CONV mice but would have no effect in GF mice with no inherent microbiome. C57BL/6J CONV and GF mice received either an antibiotic solution (Ampicillin, Ciprofloxacin, Metronidazole, Vancomycin, Meropenem) or a vehicle alone. After treatment, small intestinal villus height (VH), crypt depth (CD), mucosal surface area (MSA), crypt proliferation index (CPI), apoptosis, and villus and crypt cell types were assessed. Antibiotic-treated CONV (Abx-CONV) mice had taller villi, deeper crypts, increased CPI, increased apoptosis, and greater MSA compared to vehicle-treated CONV mice. Minor differences were noted in enterocyte and enterochromaffin cell proportions between groups, but goblet and Paneth cell proportions were unchanged in Abx-CONV mice compared to vehicle-treated CONV mice (p>0.05). Antibiotics caused no significant changes in VH or MSA in GF mice when compared to vehicle-treated GF mice (p>0.05). Enteral administration of broad-spectrum antibiotics to mice with a conventional microbiome stimulates ordered small intestinal mucosal growth. Mucosal growth was not seen in germ-free mice treated with antibiotics, implying that intestinal mucosal growth is associated with change in the microbiome in this model.

Asian-Pacific consensus on small intestinal bacterial overgrowth in gastrointestinal disorders: An initiative of the Indian Neurogastroenterology and Motility Association

In the clinical setting, small intestinal bacterial overgrowth (SIBO) is a frequent, but under-diagnosed entity. SIBO is linked to various gastrointestinal (GI) and non-GI disorders with potentially significant morbidity. The optimal management of SIBO is undefined while there is a lack of published consensus guidelines. Against this background, under the auspices of the Indian Neurogastroenterology and Motility Association (INMA), formerly known as the Indian Motility and Functional Diseases Association (IMFDA), experts from the Asian-Pacific region with extensive research and clinical experience in the field of gut dysbiosis including SIBO developed this evidence-based practice guideline for the management of SIBO utilizing a modified Delphi process based upon 37 consensus statements, involving an electronic voting process as well as face-to-face meetings and review of relevant supporting literature. These statements include 6 statements on definition and epidemiology; 11 on etiopathogenesis and pathophysiology; 5 on clinical manifestations, differential diagnosis, and predictors; and 15 on investigations and treatment. When the proportion of those who voted either to accept completely or with minor reservations was 80% or higher, the statement was regarded as accepted. The members of the consensus team consider that this guideline would be valuable to inform clinical practice, teaching, and research on SIBO in the Asian-Pacific region as well as in other countries.

Infection Prevention and Management in Pediatric Short Bowel Syndrome

Short bowel syndrome (SBS) is a rare disease with potentially life-threatening consequences. In addition to intestinal failure-associated liver disease, infections and other complications related to central venous catheters (CVCs) cause a significant burden to patients with SBS and may even necessitate an intestinal transplant eventually. The need for long-term central venous access and the intestinal dysfunction associated with SBS drive the need for intestinal failure-specific approach to prevent and treat infections in patients with SBS. In bacterial infections, the line can often be salvaged with proficient antibiotic therapy. Repeated catheter replacements are predisposed to recurrent infections and thrombotic complications, which may limit the long-term survival of patients with SBS. Protocol-based CVC access procedures and daily care including taurolidine and ethanol catheter locks have been shown to reduce infection rates substantially. Compromised intestinal function in SBS predisposes to small bowel bacterial overgrowth, mucosal injury, and increased permeability. These pathophysiological changes are concentrated in a subset of patients with excessive bowel dilatation and frequent bowel-derived infections. In such patients, reconstructive intestinal surgery may be indicated. Probiotics have not been effective in infection prevention in SBS and carry a significant risk of complications. While more studies focusing on the prevention of infections and their complications are needed, protocol-based approach and multidisciplinary teams in the care of patients with SBS have been shown to reduce complications and improve outcomes.

Complementary and antagonistic effects of combined glucagon-like peptide-2 and glucagon-like peptide-1 receptor agonist administration on parameters relevant to short bowel syndrome

BACKGROUND

Short Bowel Syndrome (SBS) is characterized by debilitating malabsorption requiring parenteral nutrition. The intestinotrophic glucagon-like peptide-2 receptor agonist, h[Gly2]GLP2, is currently used to treat patients with SBS. Recent evidence suggests that GLP-1 receptor agonists such as Exendin-4 (Ex4) may also be beneficial in SBS given their ability to increase intestinal growth and delay gastric emptying (GE).

METHODS

Intestinal growth, body weight (BW), food intake (FI), GE, gastrointestinal (GI) transit, intestinal permeability, and glucose tolerance were investigated in male and female C57/BL6 mice following vehicle, h[Gly2]GLP2 or Ex4 treatment, alone or in combination at "low", "medium", and "high" doses (0.1, 0.5, 1.0 and 0.01, 0.05, 0.1 μg/g, respectively).

RESULTS

Only the h[Gly2]GLP2 low/Ex4 high-dose combination increased small intestinal (SI) weight, in an additive manner, compared to vehicle and both mono-agonists (P<0.01-0.001), via increases in villus height (P<0.01) and SI length (P<0.05), respectively. This combination had no effects on BW, FI and fat, liver, spleen, heart and kidney weights, but reduced GI transit (P<0.001) compared to low-dose h[Gly2]GLP2 mono-treatment, and abrogated the inhibitory effects of high-dose Ex4 on GE (P<0.01) and of low-dose h[Gly2]GLP2 on intestinal permeability (P<0.05). Ex4-induced improvements in glucose homeostasis were maintained upon combination with h[Gly2]GLP2 (P<0.001).

CONCLUSIONS

These findings suggest that combining specific doses of GLP-2-based therapies and GLP-1 receptor agonists additively improves SI growth and GI transit without detrimental effects on BW, FI, GE, and glucose homeostasis, and may therefore be a useful approach to the treatment of patients with SBS. This article is protected by copyright. All rights reserved.

[Short bowel syndrome: From intestinal insufficiency to intestinal adaptation]

The short bowel syndrome results from an extensive intestinal resection. When intestinal function is below the minimum necessary for the absorption of macronutrients, water and electrolytes, short small bowel syndrome is responsible for chronic intestinal failure. The management is then parenteral nutrition. The evolution of the short bowel syndrome is schematically divided into three successive periods: (a) Immediate postoperative period lasting 3 to 6 weeks; (b) adaptive period lasting about 2 years and (c) stabilization period. However, the development of hyperphagia, spontaneous intestinal adaptation allowing an increase in the absorption surface area and in secretion of enterohormones and a modification of the microbiota occur spontaneously, improving intestinal absorption and decreasing dependence on parenteral nutrition. This review summarizes the main positive and negative pathophysiological consequences of extensive intestinal resection and the nutritional and drug management of short bowel syndrome in adults.

Progress in understanding of relationship between gut microbiota and gastrointestinal motility

Gastrointestinal motility disorders are a group of common clinical disorders in which abnormal gastrointestinal motility is the major pathogenesis, including irritable bowel syndrome, functional dyspepsia, and diabetic gastroparesis. With the rapid development of microbial sequencing technology in the past 10 years, the understanding of the gut microbiota has greatly improved, and it is generally found that patients with gastrointestinal motility diseases have gut microbiota disorders. Some progress has been made on the correlation between gut microbiota and gastrointestinal motility. This review aims to elucidate the relationship between gut microbiota and gastrointestinal motility and the mechanism of their interaction.

Short-Bowel Syndrome: Epidemiology, Hospitalization Trends, In-Hospital Mortality, and Healthcare Utilization

INTRODUCTION

Short-bowel syndrome (SBS) is a common cause of chronic intestinal failure and is associated with increased morbidity, mortality, poor quality of life, and an increased burden on healthcare costs.

METHODS

We used the US Nationwide Inpatient Sample database from 2005 to 2014. We identified adult SBS hospitalizations by using a combination of International Classification of Diseases, Ninth Revision, Clinical Modification codes. We studied the demographics of the patients with SBS and analyzed the trends in the number of hospitalizations, in-hospital mortality, and healthcare costs. We also identified the risk factors associated with in-hospital mortality.

RESULTS

A total of 53,040 SBS hospitalizations were identified. We found that SBS-related hospitalizations increased by 55% between 2005 (N = 4037) and 2014 (N = 6265). During this period, the in-hospital mortality decreased from 40 per 1000 to 29 per 1000 hospitalizations, resulting in an overall reduction of 27%. Higher mortality was noted in SBS patients with sepsis (6.7%), liver dysfunction (6.2%), severe malnutrition (6.0%), and metastatic cancer (5.4%). The overall mean length of stay (LOS) for SBS-related hospitalizations was 14.7 days, with a mean hospital cost of $34,130. We noted a steady decrease in the LOS, whereas the cost of care remained relatively stable.

CONCLUSIONS

The national burden of SBS-related hospitalizations continues to rise, and the mortality associated with SBS has substantially decreased. Older SBS patients with sepsis, liver dysfunction, severe malnutrition, and metastatic cancer had the highest risk of mortality. Healthcare utilization in SBS remains high. healthcare utilization; hospitalization trend; mortality; research and diseases; short-bowel syndrome.

Restricted v. unrestricted oral intake in high output end-jejunostomy patients referred to reconstructive surgery

The major complication of end jejunostomy is excessive fluid and electrolyte loss through the stoma, leading to hypovolaemia and dyselectrolytaemia within days and malnutrition within weeks. The aim was to compare the results of two nutritional approaches: unrestricted and restricted oral intake in patients with end jejunostomy commencing home parenteral nutrition (HPN) in terms of liver and renal biochemical markers and time to reconstructive bowel surgery with correlation to stoma output. Twenty patients with stabilised high output end-jejunostomy were divided into two groups. Group A consisted of ten patients with oral intake restricted to keep stomal output under 1000 ml. Group B consisted of ten patients with unrestricted oral intake. The following parameters were evaluated over 6 months: stomal output, self-estimation of general condition, body weight gain, plasma bilirubin and creatinine, number of hospitalisations prior to reconstructive surgery, the frequency of ostomy bag emptying, feelings of hunger and thirst in the daytime, and the time to reconstructive surgery. Stoma losses were compensated by parenteral supply. In group B, lower quality of life was observed, reflected by weakness, permanent feelings of hunger and thirst and the need for night-time emptying of the stoma bag. Patients in group B developed more complications and required more time to prepare for surgery. One death occurred in group B due to renal insufficiency followed by septic complications. Restricted oral intake seems to be more effective for prevention of HPN-related complications and shortening of time to surgery. Unrestricted oral intake appears to provoke uncontrolled losses of energy and protein, inhibiting weight gain.

Gut fermentation syndrome: A systematic review of case reports

BACKGROUND

The gut fermentation syndrome (GFS), also known as the endogenous alcohol fermentation syndrome or auto brewery syndrome, is a rare and underdiagnosed medical condition where consumed carbohydrates are converted to alcohol by the microbiota in the gastrointestinal or urinary tract. The symptoms of GFS can have severe impact on patients' wellbeing and can have social and legal consequences. Unfortunately, not much is reported about GFS. The aim of this systematic review was to assess the evidence for GFS, causal micro-organisms, diagnostics, and possible treatments.

METHODS

A protocol was developed prior to initiation of the systematic review (PROSPERO 207182). We performed a literature search for clinical studies on 1 September 2020 using PubMed and Embase. We included all clinical studies, including case reports that described the GFS.

RESULTS

In total, 17 case reports were included, consisting of 20 patients diagnosed with GFS. The species that caused the GFS included Klebsiella pneumoniae, Candida albicans, C. glabrata, Saccharomyces cerevisiae, C. intermedia, C. parapsilosis, and C. kefyr.

CONCLUSIONS

GFS is a rare but underdiagnosed disease in daily practice. The disease is mostly reported by Saccharomyces and Candida genera, and some cases were previously treated with antibiotics. Studies in Nonalcoholic Fatty Liver disease suggest a bacterial origin of endogenous alcohol-production, which might also be causal micro-organisms in GFS. Current treatments for GFS include antibiotics, antifungal medication, low carbohydrate diet, and probiotics. There might be a potential role of fecal microbiota transplant in the treatment of GFS.

Human placental-derived stem cell therapy ameliorates experimental necrotizing enterocolitis

Necrotizing enterocolitis (NEC), a life-threatening intestinal disease, is becoming a larger proportionate cause of morbidity and mortality in premature infants. To date, therapeutic options remain elusive. Based on recent cell therapy studies, we investigated the effect of a human placental-derived stem cell (hPSC) therapy on intestinal damage in an experimental NEC rat pup model. NEC was induced in newborn Sprague-Dawley rat pups for 4 days via formula feeding, hypoxia, and LPS. NEC pups received intraperitoneal (ip) injections of either saline or hPSC (NEC-hPSC) at 32 and 56 h into NEC induction. At 4 days, intestinal macroscopic and histological damage, epithelial cell composition, and inflammatory marker expression of the ileum were assessed. Breastfed (BF) littermates were used as controls. NEC pups developed significant bowel dilation and fragility in the ileum. Further, NEC induced loss of normal villi-crypt morphology, disruption of epithelial proliferation and apoptosis, and loss of critical progenitor/stem cell and Paneth cell populations in the crypt. hPSC treatment improved macroscopic intestinal health with reduced ileal dilation and fragility. Histologically, hPSC administration had a significant reparative effect on the villi-crypt morphology and epithelium. In addition to a trend of decreased inflammatory marker expression, hPSC-NEC pups had increased epithelial proliferation and decreased apoptosis when compared with NEC littermates. Further, the intestinal stem cell and crypt niche that include Paneth cells, SOX9+ cells, and LGR5+ stem cells were restored with hPSC therapy. Together, these data demonstrate hPSC can promote epithelial healing of NEC intestinal damage.NEW & NOTEWORTHY These studies demonstrate a human placental-derived stem cell (hPSC) therapeutic strategy for necrotizing enterocolitis (NEC). In an experimental model of NEC, hPSC administration improved macroscopic intestinal health, ameliorated epithelial morphology, and supported the intestinal stem cell niche. Our data suggest that hPSC are a potential therapeutic approach to attenuate established intestinal NEC damage. Further, we show hPSC are a novel research tool that can be utilized to elucidate critical neonatal repair mechanisms to overcome NEC.

Gut Microbial Dysbiosis in the Pathogenesis of Gastrointestinal Dysmotility and Metabolic Disorders

Of all microorganisms in the human body, the largest and most complex population resides in the gastrointestinal (GI) tract. The gut microbiota continuously adapts to the host environment and serves multiple critical functions for their hosts, including regulating host immunity, procuring energy from food, and preventing the colonization of pathogens. Mounting evidence has suggested gut microbial imbalance (dysbiosis) as a core pathophysiology in the development of GI motility and metabolic disorders, such as irritable bowel syndrome and diabetes. Current research has focused on discovering associations between these disorders and gut microbial dysbiosis; however, whether these associations are a consequence or cause is still mostly unexplored. State-of-the-art studies have investigated how gut microbes communicate with our body systems through microbiota-derived metabolites and how they are able to modulate host physiology. There is now mounting evidence that alterations in the composition of small intestinal microbes have an association with GI dysmotility and metabolic disorders. Although treatment options for gut microbial dysbiosis are currently limited, antibiotics, fecal microbiota transplantation, probiotics, and dietary interventions are currently the best options. However, treatment with broad-spectrum antibiotics has been viewed with skepticism due to the risk of developing antibiotic resistant bacteria. Studies are warranted to elucidate the cellular and molecular pathways underlying gut microbiota-host crosstalk and for the development of a powerful platform for future therapeutic approaches. Here, we review recent literature on gut microbial alterations and/or interactions involved in the pathophysiology of GI dysmotility and metabolic disorders.

Risk Factors for Renal Impairment in Adult Patients With Short Bowel Syndrome

Renal impairment is a common complication in patients with intestinal failure that is mostly caused by short bowel syndrome (SBS) and is associated with adverse outcomes that severely affect the quality of life or even survival. The prevalence and risk factors for renal impairment in patients with SBS remain unclarified. Therefore, we aimed to determine the prevalence of renal impairment and identify potential risk factors for renal impairment in adult patients with SBS. We retrospectively identified 199 patients diagnosed with SBS admitted to the Department of General Surgery between January 1, 2012 and January 1, 2019, from a prospectively maintained database. Overall, 56 patients (28.1%) with decreased renal function (eGFR < 90 mL/min/1.73 m²). The median duration of SBS was 7 months (IQR, 3-31 months) and the mean eGFR was 103.1 ± 39.4 mL/min/1.73 m². Logistic regression modeling indicated that older age [odds ratio (OR), 1.074; 95% CI, 1.037-1.112, P < 0.001], kidney stones (OR, 4.887; 95% CI, 1.753-13.626; P = 0.002), decreased length of the small intestine (OR, 0.988; 95% CI, 0.979-0.998; P = 0.019), and prolonged duration of SBS (OR, 1.007; 95% CI, 1.001-1.013; P = 0.046) were significant risk factors for renal impairment. This is the largest study that has specifically explored the risk factors for renal impairment in a large cohort of adults with SBS. The present study showed that renal function should be closely monitored during treatment, and patients should be given prophylactic interventions if necessary. This retrospective study is a part of clinical study NCT03277014, registered in ClinicalTrials.gov PRS. And the PRS URL is http://register.clinicaltrials.gov.

Antibiotic Utilization and Infection Among Infants with Abdominal Wall Defects

BACKGROUND

Neonates with abdominal wall defects are at an increased infection risk because of the defect itself and prolonged neonatal intensive care unit (NICU) stays. Antibiotic prophylaxis until closure of the defect is common. However, infection risk and antibiotic use have not been well quantified in these infants.

METHODS

A retrospective cohort study of infants with abdominal wall defects (gastroschisis and omphalocele) admitted to a single-center NICU from 2007 to 2018. Demographic and clinical information, including microbiologic studies, antibiotic dosing and surgical care, were collected. Antibiotic use was quantified using days of therapy (DOT) per 1000 patient-days. Sepsis was defined as culture of a pathogen from a normally sterile site.

RESULTS

Seventy-four infants were included; 64 (86%) with gastroschisis and 10 (14%) with omphalocele. Median day of closure was 8 days [interquartile range (IQR) 6-10, range 0-31]. All infants received ≥1 course of antibiotics; median antibiotic DOT/infant was 24.5 (IQR 18-36) for an average of 416.5 DOT per 1000 patient-days. Most antibiotic use was preclosure prophylaxis (44%) and treatment of small intestinal bowel overgrowth (24%). Suspected and proven infection accounted for 26% of all antibiotic use. Skin and soft tissue infection (13/74, 18%) and late-onset sepsis (11/74, 15%) were the most common infections; 2 infants had sepsis while on antibiotic prophylaxis. All infants survived to discharge.

CONCLUSIONS

Most antibiotic use among infants with abdominal wall defects was prophylactic. Infection on prophylaxis was rare, but 35% of infants had infection after prophylaxis. Improved stewardship strategies are needed for these high-risk infants.

Scheduled Empiric Antibiotics May Alter the Gut Microbiome and Nutrition Outcomes in Pediatric Intestinal Failure

BACKGROUND

In this study, we aim to determine the effect of scheduled antibiotics on gut microbiome in pediatric intestinal failure (IF) and to evaluate the effect of the gut microbiome on nutrition outcomes in IF.

METHODS

Fecal samples were collected at regular intervals from pediatric patients with IF for gut microbiome comparison between 2 cohorts: (group 1) those on scheduled prophylactic antibiotics and (group 2) those who were not on scheduled antibiotics. Gut microbiome composition and diversity were compared among the 2 cohorts. The association among gut microbiome composition, diversity, and nutrition outcomes (mainly ability to decrease parenteral nutrition [PN] energy requirement and ability to attain positive growth) was also determined.

RESULTS

The microbiome of patients with IF on scheduled antibiotics differed significantly from those not on scheduled antibiotics. Abundance of certain Gram-negative and pathogenic bacteria (Pseudomonas, Prevotella, and Sutterella) was higher in the scheduled cohort. Patients with decreased Enterobacteriaceae demonstrated a greater ability to demonstrate a reduction in PN requirement, as well as attain positive growth.

CONCLUSION

Scheduled antibiotics may alter the gut microbiome in children IF, which in turn may have an influence on important nutrition outcomes in pediatric IF. Further larger, multicenter studies are needed to determine the effect of scheduled antibiotics on the gut microbiome in this patient population and their overall effect on nutrition outcomes.

Broad-spectrum antibiotics alter the microbiome, increase intestinal fxr, and decrease hepatic steatosis in zebrafish short bowel syndrome

Short bowel syndrome (SBS) is associated with changes in the intestinal microbiome and marked local and systemic inflammation. There is also a late complication of SBS, intestinal failure associated liver disease (IFALD) in which hepatic steatosis progresses to cirrhosis. Most patients with SBS arrive at massive intestinal resection after a contaminating intraabdominal catastrophe and have a history of exposure to broad-spectrum antibiotics. We therefore investigated whether the administration of broad-spectrum antibiotics in conjunction with SBS in zebrafish (ZF) would replicate these systemic effects observed in humans to identify potentially druggable targets to aid in the management of SBS and resulting IFALD. In zebrafish with SBS, broad-spectrum antibiotics altered the microbiome, decreased inflammation, and reduced the development of hepatic steatosis. After two weeks of broad-spectrum antibiotics, these fish exhibited decreased alpha diversity, with less variation in microbial community composition between SBS and sham fish. Additionally, administration of broad-spectrum antibiotics was associated with decreased expression of intestinal toll-like receptor 4 (tlr4), increased expression of the intestinal gene encoding the Farnesoid X receptor (fxr), decreased expression of downstream hepatic cyp7a1, and decreased development of hepatic steatosis. SBS in zebrafish reproducibly results in increased epithelial surface area as occurs in human patients who demonstrate intestinal adaptation, but antibiotic administration in zebrafish with SBS reduced these gains with increased cell death in the intervillus pocket that contains stem/progenitor cells. These alternate states in SBS zebrafish might direct the development of future human therapies.NEW & NOTEWORTHY In a zebrafish model that replicates a common clinical scenario, systemic effects of the administration of broad-spectrum antibiotics in a zebrafish model of SBS identified two alternate states that led to the establishment of fat accumulation in the liver or its absence. Broad-spectrum antibiotics given to zebrafish with SBS over 2 wk altered the intestinal microbiome, decreased intestinal and hepatic inflammation, and decreased hepatic steatosis.

Vitamin C in Home Parenteral Nutrition: A Need for Monitoring

To date, there are no recommendations about screening plasma vitamin C concentration and adjust its supplementation in patients on long-term home parenteral nutrition (HPN). The aim of this study was to evaluate vitamin C status and determine if a commercial multivitamin preparation (CMVP) containing 125 mg of vitamin C is sufficient in stable patients on HPN. All clinically stable patients receiving HPN or an intravenous fluid infusion at least two times per week for at least 6 months, hospitalized for nutritional assessment, were retrospectively included, for a total of 186 patients. We found that 29% of the patients had vitamin C insufficiency (i.e., <25 µmol/L). In univariate analysis, C-reactive protein (CRP) (p = 0.002) and intake of only 125 mg of vitamin C (p = 0.001) were negatively associated with vitamin C levels, and duration of follow-up in our referral center (p = 0.009) was positively associated with vitamin C levels. In multivariate analysis, only CRP (p = 0.001) and intake of 125 mg of vitamin C (p < 0.0001) were independently associated with low plasma vitamin C concentration. Patients receiving only CMVP with a low plasma vitamin C level significantly received personal compounded HPN (p = 0.008) and presented an inflammatory syndrome (p = 0.002). Vitamin C insufficiency is frequent in individuals undergoing home parenteral nutrition; therefore, there is a need to monitor plasma vitamin C levels, especially in patients on HPN with an inflammatory syndrome and only on CMVP.

A comparison of small bowel and fecal microbiota in children with short bowel syndrome

BACKGROUND

Babies with short bowel syndrome (SBS) have small intestinal microbial disturbances that impact gut function. Characterizing the small bowel microbiota is challenging, and the utility of sampling stool is unclear. This study compares the microbiota from fecal samples and the small bowel.

METHODS

Stool samples were collected (2016-2017) from infants with SBS and colon in continuity (COLON) or SBS with small bowel ostomy (sbSTOMA). The abundance and quantity of major bacterial genera was compared between groups and to healthy controls using 16S rRNA sequencing and qPCR. Kruskall-Wallis test was used for analysis with P values <0.05 considered significant.

RESULTS

Samples (n = 41) were collected from 15 SBS infants (<2 years) (9 sbSTOMA, 6 COLON) and 3 healthy infants. Demographics and small intestinal length did not differ between sbSTOMA and COLON infants. The microbiota of SBS groups differed significantly from healthy controls. Fecal samples contained higher quantities of bacteria, but there were no significant differences between sbSTOMA and COLON groups in the abundance of facultative or obligate anaerobes, anti-inflammatory Clostridia, Enterobacteriaceae, or Bifidobacterium.

CONCLUSION

Infants with SBS have disturbances to their intestinal microbiota. Sampling small intestinal effluent is challenging. Stool samples may provide a window into the more proximal microbial community.

TYPE OF STUDY

Diagnostic.

LEVEL OF EVIDENCE

Level II.

Initial Evaluation and Care of the Patient with New-Onset Intestinal Failure

A total parenteral nutrition (TPN) formula needs to be correctly compounded with the help of a pharmacist and patients cycled to ensure they are tolerating the TPN volume. Selection of and close working relationship with a home infusion company needs to be arranged prior to hospital discharge and can be coordinated with the help of a hospital case manager. For Medicare patients, a certificate of medical necessity must be completed and signed prior to hospital discharge. Patients should undergo education regarding catheter care, infusion pump programming, and preparation of the TPN solution with additives, such as multivitamins and trace elements.

Effects of Probiotics on Intestinal Failure-Associated Liver Disease in Adult Patients Receiving Prolonged Parenteral Support: A Tertiary Care Center Experience

BACKGROUND

It has been hypothesized that dysbiosis plays a significant role in the pathogenesis of intestinal failure-associated liver disease (IFALD). Therefore, we aimed to investigate the effect of probiotics on IFALD in patients receiving parenteral support, namely home parenteral nutrition (HPN) and home intravenous fluids (HIVFs).

METHODS

We retrospectively reviewed charts of patients with intestinal failure who received HPN or HIVF for >2 weeks at our tertiary center between January 2005 and August 2016. We excluded patients <18 years of age, patients with other causes of liver disease, patients who used probiotics for <30 days, patients with <6 months' follow-up, and those who had long-term antibiotic use (>30 days). Bivariable and multivariable logistic regression analyses were used in this study.

RESULTS

A total of 282 patients who received parenteral support were included. Eighty-five percent of our sample received PN. A total of 78 (27.7%) patients used probiotics. The prevalence of IFALD in patients who used probiotics was 35.9% vs 54.4% in patients who did not use probiotics, P = .005. In multivariable analysis, only small-bowel length of 10-90 cm and HPN use showed a significant impact on IFALD, odds ratio (OR) = 4.394 (95% confidence interval [CI], 1.635-11.814; P = .003) and OR = 4.502 (95% CI 1.412-14.351; P = .011), respectively.

CONCLUSION

Our study revealed that the prevalence of IFALD was comparable among the probiotic users and nonusers. Only small bowel length of 1090 cm and HPN use showed a significant impact on IFALD.

Short Bowel Syndrome

Purpose of Review

Short gut syndrome is life-altering and life-threatening disease resulting most often from massive small bowel resection. Recent advances in understanding of the perturbed physiology in these patients have translated into improved care and outcomes. This paper seeks to review the advances of care in SBS patients.

Recent Findings

Anatomic considerations still predominate the early care of SBS patients, including aggressive preservation of bowel and documentation of remnant bowel length and quality. Intestinal adaptation is the process by which remnant bowel changes to fit the physiologic needs of the patient. Grossly, the bowel dilates and elongates to increase intestinal weight and protein content. Architectural changes are noted, such as villus lengthening and deepening of crypts. In addition, gene expression changes occur that function to maximize nutrient uptake and fluid preservation. Management is aimed at understanding these physiologic changes and augmenting them whenever possible in an effort to gain enteral autonomy. Complication mitigation is key, including avoidance of catheter complications, bloodstream infections, cholestasis, and nutrient deficiencies.

Summary

Multidisciplinary teams working together towards intestinal rehabilitation have shown improved outcomes. Today's practioner needs a current understanding of the ever-evolving care of these patients in order to promote enteral autonomy, recognize complications, and counsel patients and families appropriately.

Fecal Microbiomes in Premature Infants With and Without Parenteral Nutrition-Associated Cholestasis

INTRODUCTION

Premature infants often require parenteral nutrition (PN) until they reach enteral autonomy which puts them at risk of developing PN-associated cholestasis (PNAC). We sought to compare longitudinal changes in fecal microbiomes of premature infants who developed PNAC versus those who did not despite being on similar PN doses.

METHODS

Stool samples from premature infants (gestational age <30 weeks) who developed direct bilirubin ≥1.5 mg/dL while receiving PN were classified as precholestasis, cholestasis, or postcholestasis based on bilirubin levels at the time of sample acquisition and were compared to matched control groups 1, 2, and 3, respectively.

RESULTS

A total of 102 fecal samples from 8 cases and 10 controls were analyzed. Precholestasis samples were more abundant in phylum Firmicutes and genus Staphylococcus, whereas control 1 was more abundant in phylum Proteobacteria and genus Escherichia-Shigella. Nonmetric multidimensional scaling ordination plots based on the taxonomic composition of early fecal samples revealed significant separation between cases and controls. On indicator species analysis, genus Bacilli was more prevalent in samples from the precholestasis group, whereas genus Escherichia-Shigella was more prevalent in control 1. With feeding advances, weaning of PN and resolution of PNAC, most differences in microbiota resolved with the exception of control 3 group being more diverse compared to the postcholestasis group.

CONCLUSIONS

Premature neonates who develop PNAC, compared to those who do not, show significantly different fecal microbiomes preceding the biochemical detection of cholestasis.

A Rare Case of Primary Midgut Volvulus Necessitating Extensive Bowel Resection in an Adult

A cause of acute intestinal obstruction in adults, midgut volvulus can be categorized into two types: primary type with no identifiable underlying cause, and secondary type that occurs in the presence of a predisposing condition such as, postoperative adhesions. Primary midgut volvulus can lead to bowel ischemia and necrosis, making an extensive bowel resection imminent. A potential consequence of bowel resection is short-bowel syndrome - a failure of digestion and absorption by the intestines, leading to malnutrition and other complications. As such, we report the diagnosis and management of primary midgut volvulus - a rare entity in adults - occurring in an adult patient.

The bacterial communities of the small intestine and stool in children with short bowel syndrome

Short bowel syndrome (SBS) presents an increasing problem in pediatrics. SBS often results from surgical resection of necrotic bowel following necrotizing enterocolitis or treatment of anatomic gastrointestinal defects. SBS is associated with significant morbidity and mortality, and creates substantial burdens for patients, families, and the health system. Recent reports have demonstrated that the fecal microbiome of children with SBS is significantly different from healthy control and severe intestinal microbial imbalances is associated with poor growth. We hypothesized that children with SBS and adverse clinical features such as PN dependent, shorter bowel length and lack of ileocecal valve would demonstrate more gut dysbiosis compare with the SBS non-PN dependent. An improved understanding of SBS pathogenesis would enhance management and potentially suggest new interventions. We studied microbial communities of SBS and control non-SBS patients from the jejunum, obtained endoscopically or by ostomy aspiration, and stool. We enrolled SBS patients who did and did not require parenteral nutrition (PN), as a surrogate marker for the seriousness of their disease. We studied the microbiota using high-throughput DNA sequencing of 16S rRNA genes and statistical analyses. We found that microbial diversity was significantly greater in jejunal aspirate than in stool samples in SBS patients, unlike non-SBS patients; that SBS patients receiving enteral feeds had greater diversity, and that SBS patients on PN and enteral feeds had lower differences in diversity in jejunal vs. stool samples. We found a trend toward increased diversity in patients with an intact ileocecal valve, and found that certain taxa were more abundant in the certain sample types, and in SBS patients vs. non-SBS patients. SBS patients have lower microbial diversity, especially patients with more severe disease, patients requiring PN, and those lacking an ileocecal valve. SBS patients, particularly those with more complex characteristics, exhibit differences in their intestinal microbiota. Particular individual taxa were over- and under-represented in patients with more unfavorable disease. While diminished diversity and alterations in microbiota composition are likely consequences of SBS, future efforts aimed at increasing microbial diversity and interventions targeting specific microbiota characteristics might constitute a testable approach to ameliorate some clinical SBS clinical consequences.

Cholestasis affects enteral tolerance and prospective weight gain in the NICU

BACKGROUND

Intestinal Failure-Associated Liver Disease is characterized by cholestasis and hepatic dysfunction due to parenteral nutrition (PN) therapy. We described key features of cholestatic infants receiving PN to assess overall outcomes in this population at our institution.

METHODS

This is a retrospective single center study of 163 neonates grouped into cholestatic (n = 63) and non-cholestatic (n = 100) as defined by peak conjugated bilirubin of ≥2.0 mg/dL or < 0.8 mg/dL, respectively. Univariate and multiple regression models were used to study associations between variables and outcomes of interest.

RESULTS

Lower Apgar scores (4 ± 3 vs. 6 ± 3, p-value = <0.005 at 1 min; 6 ± 2 vs. 7 ± 2, p < 0.005 at 5 min) and lower birth weight (adj β [SE] = 0.62 [0.27], p-value = 0.024) were risk factors for developing cholestasis. Cholestatic infants were more likely to have had gastrointestinal surgery (31 [49%] vs. 15 [15%], p-value <0.005), received PN for a longer duration (40 ± 39 days vs. 11 ± 7 days, p-value <0.005), and started enteral feeds later in life (86 ± 23 days vs. 79 ± 20 days, p-value <0.005) when compared to non-cholestatic infants. Weight percentiles in cholestatic infants were lower both at hospital discharge (14 ± 19 vs. 24 ± 22, p-value <0.005) and at 6 months of age (24 ± 28 vs. 36 ± 31, p-value = 0.05).

CONCLUSIONS

Cholestasis in the NICU is a multifactorial process, but it has a long lasting effect on prospective weight gain in infants who receive PN in the NICU. This finding highlights the importance of follow-up for adequate growth and the potential benefit from aggressive nutritional support.

Short bowel mucosal morphology, proliferation and inflammation at first and repeat STEP procedures

BACKGROUND

Although serial transverse enteroplasty (STEP) improves function of dilated short bowel, a significant proportion of patients require repeat surgery. To address underlying reasons for unsuccessful STEP, we compared small intestinal mucosal characteristics between initial and repeat STEP procedures in children with short bowel syndrome (SBS).

METHODS

Fifteen SBS children, who underwent 13 first and 7 repeat STEP procedures with full thickness small bowel samples at median age 1.5 years (IQR 0.7-3.7) were included. The specimens were analyzed histologically for mucosal morphology, inflammation and muscular thickness. Mucosal proliferation and apoptosis was analyzed with MIB1 and Tunel immunohistochemistry.

RESULTS

Median small bowel length increased 42% by initial STEP and 13% by repeat STEP (p=0.05), while enteral caloric intake increased from 6% to 36% (p=0.07) during 14 (12-42) months between the procedures. Abnormal mucosal inflammation was frequently observed both at initial (69%) and additional STEP (86%, p=0.52) surgery. Villus height, crypt depth, enterocyte proliferation and apoptosis as well as muscular thickness were comparable at first and repeat STEP (p>0.05 for all). Patients, who required repeat STEP tended to be younger (p=0.057) with less apoptotic crypt cells (p=0.031) at first STEP. Absence of ileocecal valve associated with increased intraepithelial leukocyte count and reduced crypt cell proliferation index (p<0.05 for both).

CONCLUSIONS

No adaptive mucosal hyperplasia or muscular alterations occurred between first and repeat STEP. Persistent inflammation and lacking mucosal growth may contribute to continuing bowel dysfunction in SBS children, who require repeat STEP procedure, especially after removal of the ileocecal valve.

LEVEL OF EVIDENCE

Level IV, retrospective study.

Intestinal microbiota in short bowel syndrome

Children with short bowel syndrome have significant changes to their intestinal microbiota after intestinal loss. The purpose of this article is to understand the potential implications of these changes on gut function, hepatic cholestasis and overall nutrition. Possible therapies to restore the commensal bacterial community in these patients will also be reviewed.

Etiology and prognosis of pediatric short bowel syndrome

Pediatric intestinal failure is a complex and devastating condition defined as the inability of the intestine to absorb an adequate amount of fluid and nutrients to sustain life. The primary goal of intestinal failure treatment is to achieve enteral autonomy with a customized treatment plan. Although recent improvements in intestinal failure patient care have led to significant improvements in the morbidity and mortality rate, children with intestinal failure are at risk for multiple complications such as intestinal failure associated liver disease, recurrent septic episodes, central line complications, metabolic bone disease, impaired kidney function, and failure to thrive. In this article, we review the current literature on the etiology and factors affecting prognosis of pediatric IF.

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.

Small Intestinal Bacterial Overgrowth: Nutritional Implications, Diagnosis, and Management

Small intestinal bacterial overgrowth (SIBO), characterized by the presence of excessive bacteria in the small intestine, is typically described as a malabsorptive syndrome occurring in the context of gut stasis syndromes. SIBO is now considered to be a disorder associated with diverse clinical conditions without classic risk factors for SIBO and a cause of several nonspecific gastrointestinal and nongastrointestinal symptoms. Because there is currently no gold standard for diagnosing SIBO, its prevalence and role in the pathogenesis of other diseases remain uncertain; as does optimal treatment of patients with relapsing symptoms.

Obesity increases the risk of small intestinal bacterial overgrowth (SIBO)

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) has been associated with anatomical and motility-related abnormalities. Specifically, obesity has been postulated to alter small bowel motility, leading to SIBO.

AIMS

(i) Assess the prevalence of SIBO in obesity; (ii) determine the relationship of obesity and SIBO, using small bowel transit time (SBTT) and pH; (iii) profile the gut microbiome in obese and non-obese patients with SIBO.

METHODS

Thirty consecutive participants referred for SIBO underwent lactulose breath tests (LBTs) and wireless motility capsule (WMC) studies. Composition of the intestinal microbiome was assessed by analyzing samples from three different gastrointestinal sites via 16S rRNA gene-sequencing.

KEY RESULTS

SIBO was more frequent among obese patients vs non-obese patients (88.9% vs 42.9%, P < .05). Obesity did not correlate with small bowel transit time (SBTT), gastric pH, and small bowel pH. In patients with normal SBTT, obesity was associated with an 11-fold increase (P = .05) in the risk of SIBO. Whereas in those with prolonged SBTT, there was no correlation between obesity and SIBO. Obese vs non-obese patients exhibited significant differences in microbiome diversity in rectal samples. Obesity was associated with increased odds of developing SIBO (P = .04) in multivariate regression analyses.

CONCLUSIONS AND INFERENCES

While obesity was significantly associated with SIBO, our findings suggest that alterations in gut pH, SBTT, and decline in species richness do not account for the obesity-SIBO relationship.

Is Serum Methylmalonic Acid a Reliable Biomarker of Vitamin B12 Status in Children with Short Bowel Syndrome: A Case Series

We describe 3 patients with short bowel syndrome who had persistently elevated serum methylmalonic acid (MMA) levels while being treated for vitamin B12 deficiency. Following treatment for presumed small bowel bacterial overgrowth, MMA levels normalized. Among patients with short bowel syndrome, MMA levels may have limited specificity for vitamin B12 deficiency.

Current treatment paradigms in pediatric short bowel syndrome

Pediatric short bowel syndrome (SBS) is a serious condition which occurs in children with congenital or acquired reduction in length of the small intestine. SBS results in excessive fluid loss, nutrient malabsorption, electrolyte abnormalities, increased susceptibility to infections, parenteral nutrition associated complications and affects weight gain and growth. In children, SBS is debilitating and uniformly fatal without treatment. The primary goal of treatment is to restore enteral autonomy and reduce long-term dependence on parenteral support by increasing the absorptive potential of the remnant intestine. In this review, the medical and surgical management of SBS including pharmacologic agents, parenteral nutrition, dietary strategies, surgical lengthening procedures, and small bowel transplant will be discussed.

A comparison of lipid minimization strategies in children with intestinal failure

PURPOSE

The purpose of this study was to compare outcomes of lipid minimization with either Intralipid (IL) or Omegaven® in children with intestinal failure (IF) who developed intestinal failure-associated liver disease (IFALD) while receiving parenteral nutrition (PN).

METHODS

A retrospective review of children with IF requiring PN who developed IFALD (direct bilirubin >2 mg/dL) while receiving IL (2009-2016) was performed. Clinical characteristics, nutritional, and laboratory values were compared between children treated with reduced IL or Omegaven®.

RESULTS

16 children were reviewed (8 treated with IL and 8 treated with Omegaven® at a median dose of 1g/kg/d). Both groups had similar demographics, small bowel length, and parenteral nutritional intake during the study (82.9±27.1 kcal/kg/d vs. 75.9±16.5 kcal/kg/d, p=0.54). The mean direct bilirubin (DBili) prior to initiating treatment was 7.8±4.3 mg/dL and 7.5±3.5 mg/dL (p=0.87) in the IL and Omegaven® groups, respectively. The IL group took a median of 113 days to achieve a DBili <0.5 mg/dL compared to 124 days in the Omegaven® group (p=0.49). There were no differences in markers of liver function or growth trajectories among groups.

CONCLUSIONS

Lipid minimization with either IL or Omegaven® has similar success in achieving a normal DBili in children with IF and IFALD without major differences in nutritional status or growth.

TYPE OF STUDY

Treatment Study LEVEL OF EVIDENCE: III.

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.

Long-term outcomes of pediatric intestinal failure

Management of pediatric intestinal failure has evolved in recent decades, with improved survival since the advent of specialized multidisciplinary intestinal failure centers. Though sepsis and intestinal failure associated liver disease still contribute to mortality, we now have growing data on the long-term outcomes for this population. While intestinal adaptation and parenteral nutrition weaning is most rapid during the first year on parenteral support, achievement of enteral autonomy is possible even after many years as energy and protein requirements decline dramatically with age. Intestinal transplant is an option for patients experiencing complications of long-term parenteral nutrition who are expected to have permanent intestinal failure, but outcomes are hindered by immunosuppression-related complications. Much of the available data comes from single center retrospective reports, with variable inclusion criteria, intestinal failure definitions, and follow-up durations; this limits the ability to analyze outcomes and identify best practices. As most children now survive long-term, the focus of management has shifted to the avoidance and management of comorbidities, support of normal growth and development, and optimization of quality of life for these medically and surgically complex patients.

Parenteral Nutrition-Associated Liver Disease: The Role of the Gut Microbiota

Parenteral nutrition (PN) provides life-saving nutritional support in situations where caloric supply via the enteral route cannot cover the necessary needs of the organism. However, it does have serious adverse effects, including parenteral nutrition-associated liver disease (PNALD). The development of liver injury associated with PN is multifactorial, including non-specific intestine inflammation, compromised intestinal permeability, and barrier function associated with increased bacterial translocation, primary and secondary cholangitis, cholelithiasis, short bowel syndrome, disturbance of hepatobiliary circulation, lack of enteral nutrition, shortage of some nutrients (proteins, essential fatty acids, choline, glycine, taurine, carnitine, etc.), and toxicity of components within the nutrition mixture itself (glucose, phytosterols, manganese, aluminium, etc.). Recently, an increasing number of studies have provided evidence that some of these factors are directly or indirectly associated with microbial dysbiosis in the intestine. In this review, we focus on PN-induced changes in the taxonomic and functional composition of the microbiome. We also discuss immune cell and microbial crosstalk during parenteral nutrition, and the implications for the onset and progression of PNALD. Finally, we provide an overview of recent advances in the therapeutic utilisation of pro- and prebiotics for the mitigation of PN-associated liver complications.

Isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy for cancer (ISOVANTI) trial: study protocol for a randomised clinical trial

BACKGROUND

It is believed that loosing ileocecal valve is well tolerated in patients who do not have short bowel syndrome or Crohn disease. From the hypothesis of colonic peristalsis and transit is regulated by that ileocecal valvular mechanism, we try to find out if the creation of a new pseudo-valvular mechanism as antiperistaltic anastomosis could be considered after right hemicolectomy can cause any short- or long-term changes in gastrointestinal habits.

PURPOSE

The purpose of the study at primary endpoint is to compare early (occurring within 30 days of surgery) and late (occurring during the follow-up) postoperative complications between both groups The purpose of the study at secondary endpoint is to compare intraoperative and postoperative events between experimental and control groups in terms of operating time, first oral tolerance day, first flatus and faeces, length of hospital stay and orocecal transit; comparing rates of gastrointestinal life quality and comparing mortality rates between both groups.

METHODS

The ISOVANTI trial is a randomized controlled single-centre trial comparing isoperistaltic versus antiperistaltic side-to-side anastomosis after right laparoscopic hemicolectomy. It is designed as a parallel group superiority trial.

CONCLUSIONS

It is unknown if a pseudo-valvular mechanism as antiperistaltic anastomosis can be considered has short- or long-term consequences in gastrointestinal habit. Considering the impact that ileocolic anastomosis configuration could have on the restitution of bowel transit after right hemicolectomy, we think it is indicated and necessary a randomized trial comparing iso- and antiperistaltic modalities.

TRIAL REGISTRATION

NCT02309931.