Glucagon‐Like Peptide 2 Stimulates Postresection Intestinal Adaptation in Preterm Pigs by Affecting Proteins Related to Protein,Carbohydrate, and Sulphur Metabolism

Background: Exogenous glucagon‐like peptide 2 (GLP‐2) stimulates intestinal adaptation after resection in animal models of pediatric short bowel syndrome (SBS). It is unknown whether the molecular mechanisms of such GLP‐2 effects are similar to those of postresection spontaneous adaptation. Using preterm pigs as a model, we hypothesized that GLP‐2 treatment would change the intestinal proteome within the first week after resection, relative to individuals not resected or resected without GLP‐2 treatment. Materials and Methods: Two‐day‐old preterm pigs were subjected to resection of 50% distal small intestine and fed total parenteral nutrition without (SBS) or with GLP‐2 infusion (3.5 µg/kg/h, SBS+GLP‐2) for 5 days. The proteome of the remnant proximal intestine was compared among the SBS, SBS+GLP‐2, and unresected pigs, through gel‐based proteomics. Results: Thirty‐two proteins with differential expression were identified. Ten of these proteins were affected by the resection alone (ie, SBS vs unresected pigs). Five of these resection‐responsive proteins and another 22 proteins were affected by GLP‐2 infusion (ie, SBS+GLP‐2 vs SBS or unresected pigs). Resection alone mainly affected cellular structural proteins, while the added GLP‐2 treatment affected proteins involved in protein processing and the metabolism of protein, carbohydrate, and sulphur. Conclusion: In the first days following resection, proteins affected by resection plus GLP‐2 treatment differed markedly from those affected by the spontaneous intestinal adaptation following resection alone. Whether more long‐term GLP‐2 treatment may affect the intestinal proteome following intestinal resection remains unknown.     

Risk of Intestinal Malignancy in Patients With Short Bowel Syndrome

Background: Postresection intestinal adaptation is an augmented self‐renewal process that might increase the risk of malignant transformation in the intestine. Furthermore, patients with short bowel syndrome (SBS) have other characteristics that might increase this risk. Our aim was to determine the incidence of new intestinal malignancy in SBS patients. Methods: We reviewed the records of 500 adult SBS patients identified from 1982–2013. There were 199 men and 301 women ranging in age from 19–91 years. Follow‐up from the time of diagnosis of SBS ranged from 12–484 months. A total of 186 (37%) patients were followed >5 years. Results: The cause of SBS was postoperative in 35% of patients, malignancy/radiation in 19%, mesenteric vascular disease in 17%, Crohn's disease in 16%, and other in 13%. Twenty‐eight (6%) patients received growth stimulatory medications. Fifteen percent of patients had a prior total colectomy. Twenty‐eight (6%) patients underwent intestinal transplantation, and 115 (23%) patients had a previous abdominal malignancy, including colorectal cancer in 43 patients. Thirty‐six (7%) received radiation therapy. Recurrent colon cancer was found in 2 patients, one at a stoma and the other with lung metastases. New colon cancer was found in 1 patient (0.2%), a 62‐year‐old woman with long‐standing Crohn's disease. Conclusion: The incidence of colon cancer in this heterogenous group of patients with SBS was similar to that of the normal population. This suggests that the risk of developing a new colon cancer in patients with SBS is not increased.     

Minimal Enteral Nutrition to Improve Adaptation After Intestinal Resection in Piglets and Infants

Background: Minimal enteral nutrition (MEN) may induce a diet‐dependent stimulation of gut adaptation following intestinal resection. Bovine colostrum is rich in growth factors, and we hypothesized that MEN with colostrum would stimulate intestinal adaptation, compared with formula, and would be well tolerated in patients with short bowel syndrome. Methods: In experiment 1, 3‐day‐old piglets with 50% distal small intestinal resection were fed parenteral nutrition (PN, n = 10) or PN plus MEN given as either colostrum (PN‐COL, n = 5) or formula (PN‐FORM, n = 9) for 7 days. Intestinal nutrient absorption and histomorphometry were performed. In experiment 2, tolerance and feasibility of colostrum supplementation were tested in a pilot study on 5 infants who had undergone intestinal resection, and they were compared with 5 resected infants who served as controls. Results: In experiment 1, relative wet‐weight absorption and intestinal villus height were higher in PN‐COL vs PN (53% vs 23% and 362 ± 13 vs 329 ± 7 µm, P < .05). Crypt depth and tissue protein synthesis were higher in PN‐COL (233 ± 7 µm, 22%/d) and PN‐FORM (262 ± 13 µm, 22%/d) vs PN (190 ± 4 µm, 9%/d, both P < .05). In experiment 2, enteral colostrum supplementation was well tolerated, and no infants developed clinical signs of cow’s milk allergy. Conclusion: Minimal enteral nutrition feeding with bovine colostrum and formula induced similar intestinal adaptation after resection in piglets. Colostrum was well tolerated by newly resected infants, but the clinical indication for colostrum supplementation to infants subjected to intestinal resection remains to be determined.     

Parenteral but Not Enteral Omega‐3 Fatty Acids (Omegaven) Modulate Intestinal Regrowth After Massive Small Bowel Resection in Rats

Background: The purpose of the present study was to evaluate the effects of ω‐3 fatty acids (Omegaven) on early intestinal adaptation in rats with short bowel syndrome (SBS). Methods: Male Sprague‐Dawley rats were randomly assigned to 1 of 4 groups: sham rats underwent bowel transection; SBS rats underwent 75% bowel resection; SBS‐O ω‐3 rats underwent bowel resection and were treated with oral Omegaven given by gavage; and SBS‐I ω‐3 rats underwent bowel resection and were treated with Omegaven given intraperitoneally. Rats were killed on day 14. Parameters of intestinal adaptation (bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depths, cell proliferation and apoptosis) were determined at time of death. Real‐time polymerase chain reaction was used to determine the level of Bax and Bcl‐2 messenger RNA (mRNA). Statistical analysis was performed using Kruskal‐Wallis test followed by post hoc test, with P < .05 considered statistically significant. Results: Oral ω‐3 supplementation did not significantly change intestinal regrowth. In contrast, parenteral ω‐3 in rats that underwent resection resulted in higher bowel and mucosal weights, mucosal DNA and protein in ileum, villus height in ileum, crypt depth in jejunum and ileum, and greater rates of cell proliferation in jejunum and ileum compared with SBS animals. The initial decreased levels of apoptosis corresponded with the early decrease in Bax and increase in Bcl‐2 mRNA levels. Conclusions: Parenteral but not enteral Omegaven augments and accelerates structural bowel adaptation in a rat model of SBS. Increased cell proliferation and decreased apoptosis reflect increased cell turnover in Omegaven‐treated animals.     

Colonic GLP‐2 is not Sufficient to Promote Jejunal Adaptation in a PN‐Dependent Rat Model of Human Short Bowel Syndrome

Background: Bowel resection may lead to short bowel syndrome (SBS), which often requires parenteral nutrition (PN) due to inadequate intestinal adaptation. The objective of this study was to determine the time course of adaptation and proglucagon system responses after bowel resection in a PN‐dependent rat model of SBS. Methods: Rats underwent jugular catheter placement and a 60% jejunoileal resection + cecectomy with jejunoileal anastomosis or transection control surgery. Rats were maintained exclusively with PN and killed at 4 hours to 12 days. A nonsurgical group served as baseline. Bowel growth and digestive capacity were assessed by mucosal mass, protein, DNA, histology, and sucrase activity. Plasma insulin‐like growth factor I (IGF‐I) and bioactive glucagon‐like peptide 2 (GLP‐2) were measured by radioimmunoassay. Results: Jejunum cellularity changed significantly over time with resection but not transection, peaking at days 3‐4 and declining by day 12. Jejunum sucrase‐specific activity decreased significantly with time after resection and transection. Colon crypt depth increased over time with resection but not transection, peaking at days 7‐12. Plasma bioactive GLP‐2 and colon proglucagon levels peaked from days 4‐7 after resection and then approached baseline. Plasma IGF‐I increased with resection through day 12. Jejunum and colon GLP‐2 receptor RNAs peaked by day 1 and then declined below baseline. Conclusions: After bowel resection resulting in SBS in the rat, peak proglucagon, plasma GLP‐2, and GLP‐2 receptor levels are insufficient to promote jejunal adaptation. The colon adapts with resection, expresses proglucagon, and should be preserved when possible in massive intestinal resection.     

In a Neonatal Piglet Model of Intestinal Failure,Administration of Antibiotics and Lack of Enteral Nutrition Have a Greater Impact on Intestinal Microflora Than Surgical Resection Alone

Background: Data are limited on how short bowel syndrome (SBS) affects the healthy developing intestinal microbiome, with even less assessing different SBS anatomical surgical models. This study was conducted to describe the “ileal” and “colonic” microflora in 2 surgical models of SBS. Materials and Methods: Neonatal piglets (2–5 days old) underwent intestinal resection, leaving the ileum (JI anatomy, n = 6) or removing the ileum and ileocecal valve (JC anatomy, n = 5), or sham surgery (sham; n = 4). JI, JC, and sham piglets commenced parenteral nutrition on day 0 and received ampicillin and trimethoprim‐sulfadoxine on days 0–4 for prevention of line sepsis. At day 7, ileal and colonic digesta were collected, and they were also collected from age‐matched sow‐fed piglets (n = 6). DNA extraction, sequencing, and annotation followed standard procedures. Results: Colonic and ileal bacterial genus diversity and relative bacterial abundance were greater (P < .05) in sow‐fed compared with JI, JC, and sham piglets; however, minor differences were observed in either location between sham, JI, and JC piglets and within the surgical model. In the colon, sow‐fed piglets had higher (P < .05) abundance of Lactobacillus (26%) and tended to have lower (P = .06) abundance of Enterococcus (<.1%) than JI, JC, or sham piglets, in which Lactobacillus and Enterococcus abundance averaged <.1% and 9%, respectively. Conclusions: Intestinal resection reduces bacterial diversity in the large bowel, and the difference is associated with the presence/absence of the ileum and ileocecal valve. The lack of enteral nutrition and antibiotic administration (ie, sow‐fed vs surgery) had a greater influence on the observed shift in diversity and relative abundance than intestinal resection.     

Formula Induces Intestinal Apoptosis in Preterm Pigs Within a Few Hours of Feeding

Background: Nutrition regimens influence postnatal small intestinal development, which shows prominent changes after 6 hours of suckling. Such influences are particularly important in preterm neonates as inappropriate feeding responses may predispose to gastrointestinal disorders such as necrotizing enterocolitis (NEC). The authors investigated the early morphological responses to enteral feeding, prior to the time period when a large proportion of preterm pigs normally develop clinical NEC symptoms. Methods: Preterm piglets (106‐107 days of gestation) were fed parenteral nutrition (PN) for 2 days with or without a subsequent 8‐hour or 17‐hour period of enteral nutrition (EN) with sow's colostrum or formula. Another group of piglets was delivered at 108–109 days of gestation and used for comparison to PN pigs before enteral feeding. Stereological measurements of the mucosal surface density and the volume densities of the tunica mucosa, tunica muscularis, proliferative, and apoptotic cells were made and related to microscopical NEC‐lesion score. In addition, villus length and crypt depth were measured. Results: PN‐fed piglets showed minimal PN‐induced mucosal atrophy, although their crypts were deeper, together with lower cell proliferation and higher apoptotic indices, than newborn (NB) unfed piglets. After PN, enteral feeding with colostrum, for just 8 hours, induced a rapid increase in the mucosal volume density while formula feeding was associated with an elevated number of both proliferating and apoptotic cells and a higher NEC lesion score than PN‐ or colostrum‐fed pigs. Conclusion: Enteral feeding of formula, for only a few hours, induces rapid enterocyte turnover and mucosal structural changes that may predispose to later development of NEC.     

Differential Effects on Intestinal Adaptation Following Exogenous Glucagon‐Like Peptide 2 Therapy With and Without Enteral Nutrition in Neonatal Short Bowel Syndrome

Background: We aim to study the efficacy of exogenously administered glucagon‐like peptide 2 (GLP‐2) on intestinal adaptation in 2 preclinical models of neonatal short bowel syndrome (SBS) according to remnant intestinal anatomy, with and without ileum. Furthermore, we aim to determine if this adaptive effect was potentiated with enteral nutrition (EN). Methods: Neonatal piglets were block‐randomized to 75% mid‐intestinal (JI group, retains ileum) or distal‐intestinal (JC group, has no ileum) resection or no resection (sham control) and GLP‐2 treatment (11 nmol/kg/d) or saline control for 7 days. Piglets received nutrition support, either 100% parenteral nutrition (PN; 0% EN, n = 32 in total) or 80% PN + 40% EN (n = 28 in total). Adaptation was assessed by morphological and histological changes, as well as RT quantitative polymerase chain reaction of nutrient transporters and tight junctional proteins and fat absorption. Data are analyzed by 3‐way analysis of variance (ANOVA) and 2‐way ANOVA per EN level. Results: GLP‐2 treatment lengthened villi, deepened crypts, and improved intestinal weight in the remnant intestine of JC piglets. EN was a more potent adaptive stimulus for JI piglets. Small intestinal lengthening occurred only in the JI group, when given EN. There was no difference in total fat absorption and messenger RNA expression of nutrient transporters and tight junctional proteins. Conclusions: GLP‐2 administration augmented structural adaptation in JC piglets with distal intestinal resection. Given JI anatomy, further stimulation by GLP‐2 treatment over innate adaptation and stimulation by EN was modest and restricted to ileum. The differential effect of GLP‐2 in neonatal SBS, depending on remnant anatomy, has important implications for clinical translation and planning of clinical trials.     

Colostrum supplementation restores insulin-like growth factor -1 levels and alters muscle morphology following massive small bowel resection

BACKGROUND: Colostrum protein concentrate (CPC) contains a high level of insulin-like growth factor-1 (IGF-1). IGF-1 and IGF binding protein (IGFBPs) may play an important role during the postresection adaptation response. As smooth muscle is an important site for IGF-1 action in the intestine, this study aims to (1) investigate the effect of CPC supplementation on circulating levels and tissue expression of IGF-1, IGF-1 receptor, and IGFBPs following massive small bowel resection (MSBR), and (2) characterize the effect of CPC on the muscular adaptation response following MSBR. METHODS: Four-week-old piglets underwent either a 75% MSBR or sham operation. Piglets received either a polymeric infant formula (PIF) diet or PIF supplemented with CPC for 8 weeks. Serum was analyzed by enzyme-linked immunosorbent assay, and ileal tissue assessed by molecular and histological analysis. RESULTS: There was no difference in IGF-1 or IGFBPs mRNA among groups. CPC treatment resulted in significant increases in circulating levels of IGF-1 and IGFBPs and a concurrent increase in muscle width and the number of muscle cells, but did not alter muscle cell size. CONCLUSIONS: Strategies aimed at increasing muscular adaptation may decrease Gl transit and allow greater mucosal contact time for absorption. We have shown that CPC supplementation following resection results in increased levels of circulating IGF-1, IGFBP-2, and IGFBP-3 and muscular hypertrophy. Our results suggest that IGF-1 and its mediators may play a role in the muscular adaptation response and warrant further exploration as a treatment option for short bowel syndrome.     

Long-Term Outcomes in Patients with Intestinal Failure Due to Short Bowel Syndrome and Intestinal Fistula

Short bowel syndrome (SBS) and enterocutaneous or enteroatmospheric fistulas are common indications for home parenteral nutrition (HPN). However, there are few data describing factors influencing surgical decision-making or outcomes particularly following fistula development. We aimed to compare outcomes between patients with SBS and fistulas and explore surgical decision-making. HPN-dependent adults from 2001–2018 at a national reference centre were included in this study. HPN cessation was analysed using death as competing risk. In total, 465 patients (SBS (62%), fistula (38%)) were included, with median HPN dependency of 2.6 years. In total, 203 patients underwent reconstructive surgery; while frailty was the commonest reason for not undergoing surgery (49.2%), 22.7% declined surgery. Overall, 170 ceased HPN, with a probability of 13.8%, 34.1% and 38.3% at 1, 5 and 10 years, respectively. Patients undergoing surgery had higher nutritional autonomy rates (109.8 incidences/1000 patient years) compared to those not undergoing surgery (18.1 incidences/1000 patient years; p < 0.001). A total of 295 patients (63.4%) were predicted to cease HPN based on gastrointestinal anatomy but only 162/295 (54.9%) achieved this; those unable to do so were older with a higher comorbidity index. There were no differences in long-term nutritional and survival outcomes or surgical decisions between patients with SBS and fistulas, or between enterocutaneous and enteroatmospheric fistulas. This study represents one of the largest datasets describing the ability of HPN-dependent patients with SBS or fistulas to achieve nutritional autonomy. While reconstructive surgery facilitates HPN cessation, approximately one-fifth of patients declined surgery despite HPN dependency. These data will better inform patient expectation and help plan alternative therapies.     

Functional Fiber Reduces Mice Obesity by Regulating Intestinal Microbiota

Obesity may cause metabolic syndrome and has become a global public health problem, and dietary fibers (DF) could alleviate obesity and metabolic syndrome by regulating intestinal microbiota. We developed a functional fiber (FF) with a synthetic mixture of polysaccharides, high viscosity, water-binding capacity, swelling capacity, and fermentability. This study aimed to investigate the effect of FF on obesity and to determine its prevention of obesity by modulating the gut microbiota. Physiological, histological, and biochemical parameters, and gut microbiota composition were investigated in the following six groups: control group (Con), high-fat diet group (HFD), low-fat diet group (LFD, conversion of HFD to LFD), high-fat +8% FF group (8% FF), high-fat +12% FF group (12% FF), and high-fat +12% FF + antibiotic group (12% FF + AB). The results demonstrated that 12% FF could promote a reduction in body weight and epididymal adipocyte area, augment insulin sensitivity, and stimulate heat production from brown adipose tissue (BAT) (p < 0.05). Compared with the HFD, 12% FF could also significantly improve the intestinal morphological integrity, attenuate systemic inflammation, promote intestinal microbiota homeostasis, and stabilize the production of short-chain fatty acids (SCFAs) (p < 0.05). Consistent with the results of 12% FF, the LFD could significantly reduce the body weight and epididymal adipocyte area relative to the HFD (p < 0.05), but the LFD and HFD showed no significant difference (p > 0.05) in the level of inflammation and SCFAs. Meanwhile, 12% FF supplementation showed an increase (p < 0.05) in the abundance of the Bifidobacterium, Lactococcus, and Coprococcus genus in the intestine, which had a negative correlation with obesity and insulin resistance. Additionally, the treatment with antibiotics (12% FF + AB) could inhibit the effect of FF in the HFD. The Kyoto Encyclopedia of Genes and Genomes (KEGG) function prediction revealed that 12% FF could significantly inhibit the cyanogenic amino acid metabolic pathway and decrease the serum succinate concentration relative to the HFD group. The overall results indicate that 12% FF has the potential to reduce obesity through the beneficial regulation of the gut microbiota and metabolites.     

Intestinal Microbiota Signatures Associated With Histological Liver Steatosis in Pediatric‐Onset Intestinal Failure

Background: Intestinal failure (IF)–associated liver disease (IFALD) is the major cause of mortality in IF. The link between intestinal microbiota and IFALD is unclear. Methods: We compared intestinal microbiota of patients with IF (n = 23) with healthy controls (n = 58) using culture‐independent phylogenetic microarray analysis. The microbiota was related to histological liver injury, fecal markers of intestinal inflammation, matrix metalloproteinase 9 and calprotectin, and disease characteristics. Results: Overabundance of Lactobacilli, Proteobacteria, and Actinobacteria was observed in IF, whereas bacteria related to Clostridium clusters III, IV, and XIVa along with overall diversity and richness were reduced. Patients were segregated into 3 subgroups based on dominating bacteria: Clostridium cluster XIVa, Proteobacteria, and bacteria related to Lactobacillus plantarum. In addition to liver steatosis and fibrosis, Proteobacteria were associated with prolonged current parenteral nutrition (PN) as well as liver and intestinal inflammation. Lactobacilli were related to advanced steatosis and fibrosis mostly after weaning off PN without associated inflammation. In multivariate permutational analysis of variance, liver steatosis, bowel length, PN calories, and antibiotic treatment best explained the microbiota variation among patients with IF. Conclusions: Intestinal microbiota composition was associated with liver steatosis in IF and better predicted steatosis than duration of PN or length of the remaining intestine. Our results may be explained by a model in which steatosis is initiated during PN in response to proinflammatory lipopolysaccharides produced by Proteobacteria and progresses after weaning off PN, as the L plantarum group Lactobacilli becomes dominant and affects lipid metabolism by altering bile acid signaling.     

Surgical Anatomy Does Not Affect the Progression of Intestinal Failure–Associated Liver Disease in Neonatal Piglets

Background: Intestinal failure–associated liver disease (IFALD) causes significant morbidity in neonates with short bowel syndrome (SBS) dependent on parenteral nutrition (PN). Resected ileum, with loss of the ileocecal valve (ICV), is the most common anatomy in SBS, yet its impact on IFALD has not been adequately studied. Methods: Neonatal piglets were randomized to 75% intestinal resection with jejunocolic anastomosis (JC, n = 12), 75% resection with jejunoileal anastomosis and intact ICV (JI, n = 13), PN‐fed sham (sham, n = 14), or sow‐fed control (SF, n = 8). Surgical and sham piglets received 100% PN for 14 days before bile flow was measured and blood chemistry, liver pathology, jejunal permeability, and bacterial translocation were assessed. Results: Bile flow was lower for PN‐fed compared with SF (P = .002) but not different between the PN‐fed groups. Total bilirubin (P = .03) and liver pathology (P < .001) were greater in PN‐fed than SF groups but not different between PN‐fed groups. Serum bile acids were increased in sham (P = .01) but not different between SBS groups. PN‐fed piglets with sepsis had lower bile flow (P = .001) and increased bilirubin (P = .04). Neither jejunal permeability nor bacterial translocation were different between JC, JI, or sham groups. Conclusion: Contrary to our hypothesis, the remnant anatomy does not appear to worsen the progression of IFALD. However, the role of sepsis in IFALD should be further explored, in addition to other mechanisms, including PN factors, host immune responses, and intestinal bacterial dysbiosis.     

Increased Anti‐Flagellin and Anti‐Lipopolysaccharide Immunoglobulins in Pediatric Intestinal Failure

Background: Central line–associated bloodstream infections (CLABSIs) pose a significant challenge in the lives of patients with intestinal failure (IF). We hypothesized that plasma immunoglobulins against flagellin (FLiC) and lipopolysaccharide (LPS) would be able to differentiate CLABSIs from nonbacterial febrile episodes and that levels would increase with infection and decline following appropriate antibiotic treatment. Materials and Methods: Patients with IF, due to short bowel syndrome, between the ages of 3 months and 4 years of age, were recruited at Cincinnati Children's Hospital Medical Center. Anti‐FLiC and anti‐LPS plasma antibody levels were measured in 13 children with IF at baseline, during febrile events, and also following treatment with antibiotics. These were also measured in 11 healthy children without IF who were recruited as controls. Results: Plasma anti‐FLiC IgA levels increased during febrile episodes in all patients with IF (baseline mean of 1.10 vs febrile episode mean of 1.32 optical density units, respectively; P = .046). Neither plasma anti‐FLiC nor anti‐LPS IgA or IgG levels distinguished CLABSI from nonbacterial febrile episodes compared with baseline levels. Compared with controls, patients with IF had significantly higher plasma levels of anti‐FLiC and anti‐LPS IgA at baseline. Conclusion: Plasma anti‐FLiC IgA antibody levels rise during febrile episodes but do not differentiate between nonbacterial febrile illnesses and CLABSIs in pediatric IF. However, the upregulation of these antibodies in IF suggests the baseline systemic presence of Gram‐negative bacterial products.