Small intestinal length: a factor essential for gut adaptation

Risk factors for intestinal failure in infants with necrotizing enterocolitis: a Glaser Pediatric Research Network study

OBJECTIVE

To determine risk factors for intestinal failure (IF) in infants undergoing surgery for necrotizing enterocolitis (NEC).

STUDY DESIGN

Infants were enrolled in a multicenter prospective cohort study. IF was defined as the requirement for parenteral nutrition for >or= 90 days. Logistic regression was used to identify predictors of IF.

RESULTS

Among 473 patients enrolled, 129 had surgery and had adequate follow-up data, and of these patients, 54 (42%) developed IF. Of the 265 patients who did not require surgery, 6 (2%) developed IF (OR 31.1, 95% CI, 12.9 - 75.1, P < .001). Multivariate analysis identified the following risk factors for IF: use of parenteral antibiotics on the day of NEC diagnosis (OR = 16.61, P = .022); birth weight < 750 grams, (OR = 9.09, P < .001); requirement for mechanical ventilation on the day of NEC diagnosis (OR = 6.16, P = .009); exposure to enteral feeding before NEC diagnosis (OR=4.05, P = .048); and percentage of small bowel resected (OR = 1.85 per 10 percentage point greater resection, P = .031).

CONCLUSION

The incidence of IF among infants undergoing surgical treatment for NEC is high. Variables characteristic of severe NEC (low birth weight, antibiotic use, ventilator use, and greater extent of bowel resection) were associated with the development of IF.

Surface area assessment of the murine intestinal tract as a prerequisite for oral dose translation from mouse to man

In many pharmacological and toxicological studies knowledge about the intestinal absorption, which is dependent upon the surface area of absorptive epithelia, is indispensible. Although mice are often used in such preclinical studies, very few quantitative data about their intestinal surface area are available. Especially for locally acting candidate drugs in development, this information is crucial for dose translation towards humans. Therefore, the surface area of the intestinal tract of CD-1™ IGS mice was assessed in the present study. The intestinal tracts of 12 mice were collected after euthanasia. From six animals, histological sections from the duodenum, jejunum, ileum, caecum and colon-rectum were made according to common stereological principles. Using these sections, the volumes and surface areas of each intestinal segment were estimated applying stereological counting procedures. In the other six animals, the density and surface area of the microvilli present in each intestinal segment were determined by means of scanning and transmission electron microscopy to assess the increase of the intestinal surface area attributable to the presence of microvilli. The mean total volume and surface area of the intestinal tract were 1.34 cm3 and 1.41 m2, respectively. The relative intestinal surface area (intestinal surface area divided by the body surface area) was 119. The relative intestinal surface area of mice is very similar to that of humans. The results of this study are important for the appropriate dose translation of candidate therapeutic compounds in drug development from mouse to humans.

Age-related differences in susceptibility to cisplatin-induced renal toxicity

Limited experimental models exist to assess drug toxicity in pediatric populations. We recently reported how a multi-age rat model could be used for pre-clinical studies of comparative drug toxicity in pediatric populations. The objective of this study was to expand the utility of this animal model, which previously demonstrated an age-dependent sensitivity to the classic nephrotoxic compound, gentamicin, to another nephrotoxicant, namely cisplatin (Cis). Sprague-Dawley rats (10, 25, 40 and 80 days old) were injected with a single dose of Cis (0, 1, 3 or 6 mg kg(-1) i.p.). Urine samples were collected prior and up to 72 h after treatment in animals that were >or= 25 days old. Several serum, urinary and 'omic' injury biomarkers as well as renal histopathology lesions were evaluated. Statistically significant changes were noted with different injury biomarkers in different age groups. The order of age-related Cis-induced nephrotoxicity was different than our previous study with gentamicin: 80 > 40 > 10 > 25 day-old vs 10 >or= 80 > 40 > 25-day-old rats, respectively. The increased levels of kidney injury molecule-1 (Kim-1: urinary protein/tissue mRNA) provided evidence of early Cis-induced nephrotoxicity in the most sensitive age group (80 days old). Levels of Kim-1 tissue mRNA and urinary protein were significantly correlated to each other and to the severity of renal histopathology lesions. These data indicate that the multi-age rat model can be used to demonstrate different age-related sensitivities to renal injury using mechanistically distinct nephrotoxicants, which is reflected in measurements of a variety of metabolite, gene transcript and protein biomarkers.

Intrauterine growth restriction modifies the developmental pattern of intestinal structure, transcriptomic profile, and bacterial colonization in neonatal pigs

Neonates with intrauterine growth restriction (IUGR) are prone to suffer from digestive diseases. Using neonatal pigs with IUGR, we tested the hypothesis that IUGR may induce alterations in the developmental pattern of intestinal barrier and thereby may be responsible for IUGR-associated increased morbidity. Piglets with a birth weight near the mean birth weight (+/-0.5 SD) were identified as normal birth weight (control) and piglets with a mean -2 SD lower birth weight (-30%) were defined as piglets with IUGR. The developmental pattern of intestinal structure, transcriptomic profile, and bacterial colonization was investigated from birth to d 5 postnatal. At birth, intestinal weight and length, ileal and colonic weight per unit of length, and villous sizes were lower (P < 0.05) in piglets with IUGR than in same-age control piglets. These IUGR-induced intestinal alterations further persisted, although they were less marked at d 5. Counts of adherent bacteria to ileal and colonic mucosa were greater (P < 0.05) in 2-d-old piglets with IUGR than in same-age control piglets. Dynamic analyses of the transcriptomic profile of the intestine revealed molecular evidence of IUGR-induced intestinal growth impairment that may result from a change in the cell proliferation-apoptosis balance during the first days of life, while a protective process would occur later on. In addition, changes in the expression of several genes suggest a pivotal role of both glucocorticoids and microbiota in driving IUGR intestinal development during the neonatal period.

A shorter loop in Roux-Y hepatojejunostomy reconstruction for choledochal cysts is equally effective: preliminary results of a prospective randomized study

BACKGROUND

Conventionally, an adult's standard of a 40-cm loop is adopted in Roux-Y hepatojejunostomy (RYHJ) in choledochal cyst (CDC) in children, irrespective of patient size. The redundant length of the jejunal limb may lead to complications. We compared the outcome of an individualized short Roux loop with the standard loop length in RYHJ in children with CDC.

METHODS

Two hundred eighteen children with CDC undergoing laparoscopic RYHJ were prospectively randomized into 2 groups: (1) conventional group (CG; n = 108) where a standard 35-40 cm Roux-loop length was used regardless of the child's size and (2) short loop group (SLG; n = 110) in which the Roux-loop length was based on the distance between hepatic hilum and umbilicus. Ultrasonography, upper gastrointestinal contrast studies, and laboratory tests were conducted during the follow-up period.

RESULTS

The mean Roux-loop length of SLG was significantly shorter than that of CG (Student t test, P < .05). There was no significant difference between the 2 groups in age, operative blood loss, operative time, postoperative hospital stay, and duration of drainage. In CG, 2 of (1.8%) 108 patients developed Roux-loop obstruction, whereas none was detected in SLG (0%). Mild reflux was detected in 2 CG patients and 1 SLG patient 1 month postoperatively, all of which subsided 6 months later. No episodes of cholangitis were observed in either group.

CONCLUSIONS

An individualized short Roux-loop length in RYHJ is as effective as the conventional Roux-loop length.

Short bowel syndrome: epidemiology and etiology

Pediatric short bowel syndrome (SBS) is most commonly caused by congenital or acquired conditions of the newborn. SBS is associated with an inability of the bowel to adequately absorb water and nutrients in sufficient quantities to meet caloric, fluid, and electrolyte demands, thus necessitating dependence on parenteral nutrition (PN). It is this dependence on PN, that is responsible for the majority of morbidity and mortality associated with SBS, including central venous catheter infections and PN-induced cholestatic liver dysfunction. There are very few estimates of SBS incidence and mortality in the literature. The epidemiology of SBS is reviewed and the limitations of the published literature are discussed.

Safety and efficacy of double-balloon enteroscopy in pediatric patients

BACKGROUND

Although double-balloon enteroscopy (DBE) is performed increasingly often in adults, few findings are available on the use of DBE in pediatric patients in the published literature.

OBJECTIVES

The aim of our study was to evaluate the safety and efficacy of DBE in pediatric patients.

DESIGN

A retrospective database review.

SETTING AND PATIENTS

A database analysis was performed on all pediatric patients (18 years old or younger) who underwent DBE at the Jichi Medical University Hospital between September 2000 and October 2008 selected from a total of 825 patients.

MAIN OUTCOME MEASUREMENTS

Clinical utility and safety of DBE in pediatric patients.

RESULTS

A total of 92 procedures were performed in 48 patients (27 male, 21 female) with a median age (range) of 12.2 (4-18) years. DBE was performed with the patients under general anesthesia in 43 procedures and under moderate sedation in 49 procedures. The most common indication for DBE was treatment of a stricture of a biliary anastomosis after living-donor liver transplantation with establishment of Roux-en-Y hepaticojejunostomy (23 patients). Endoscopic retrograde cholangiography using DBE was performed, and endoscopic therapy could be performed successfully in 13 (56%) patients. The second most common indication was obscure GI bleeding (10 patients); the lesions responsible for the bleeding were found in 7 (70%) patients. Other indications included surveillance and treatment of hereditary polyposis syndromes (5 patients), abdominal pain (4 patients), and inflammatory bowel disease (2 patients). The overall diagnostic yield was 65% (31 of the 48 patients). Postpolypectomy bleeding occurred in 1 case, but no other complications such as perforation and pancreatitis were observed.

LIMITATIONS

Small number of patients, participation bias, and single center's experience.

CONCLUSIONS

DBE is a safe and clinically useful endoscopic procedure in pediatric patients.

Clinical assessment of the child with intestinal failure

The management of the child with intestinal failure is complex, and it is developing into a multispecialty field of its own led by expert teams of both transplant and nontransplant surgeons, gastroenterologists, and dieticians. Patients are at risk for medical, surgical, and nutritional complications that should be anticipated so that they can be prevented or managed appropriately. Catheter associated infections and intestinal failure associated liver diseases are important complications that impact the likelihood of bowel adaptation and long-term survival. The clinical assessment of a pediatric intestinal failure patient should include evaluation of the child within the context of recognized prognostic factors.

Estudo da correlação do IMC e comprimento do intestino delgado em pacientes obesos submetidos à cirurgia bariátrica

RACIONAL: Segundo a hipótese do intestino longo, o comprimento do intestino delgado estaria relacionado à obesidade. Existem dados evolutivos, anatômicos e neuroendócrinos em favor desta afirmação. OBJETIVOS: Verificar a medida do comprimento do intestino delgado em pacientes obesos submetidos à cirurgia bariátrica e analisar a correlação entre o seu tamanho e o IMC. MÉTODO: A casuística foi composta de 30 pacientes do Serviço de Obesidade do Hospital Universitário Evangélico de Curitiba, submetidos à cirurgia bariátrica no período de março a junho de 2009, e previamente avaliados, verificando peso, altura e IMC. A técnica cirúrgica foi a de Fobi-Capella. A mensuração do intestino delgado foi realizada desde a flexura duodenojejunal à junção ileocecal, durante o trans-operatório, utilizando uma pinça de manipulação intestinal, a qual foi marcada com a medida de 10 cm. As alças intestinais foram medidas na margem anti-mesentérica, aplicando-se tensão mínima necessária para retificar as mesmas. Os dados foram correlacionados e tabulados estatisticamente, utilizando-se o método de correlação de Pearson. RESULTADOS: A média do comprimento intestinal para o sexo masculino foi de 582,5 cm e para o sexo feminino de 509,1. A partir do cálculo do coeficiente de correlação de Pearson, confirmou-se a ausência de correlação entre IMC e comprimento do intestino delgado. CONCLUSÃO: Obteve-se uma média de tamanho intestinal de 528,7 cm para toda a amostra. O comprimento do intestino delgado não possuiu correspondência com o IMC, não sendo um fator de significância neste estudo.

Short Bowel Syndrome

Short bowel syndrome (SBS) is a relatively common, often lethal, and highly costly medical problem in North America. Necrotizing enterocolitis (NEC) is the leading cause of SBS in the United States. An important fact to remember is that the length of the small bowel in a 28-week preterm infant is about 150 cm and in a term infant is about 250 cm. Twenty percent of this length is generally sufficient to allow dependence on parenteral nutrition (PN) via intestinal adaptation. This process is driven by significant increases in circulating trophic hormones, such as cholecystokinin, epidermal and keratinocyte growth factors, growth hormone, insulin-like growth factor-1, and glucagon-like peptide-2. These hormones produce hypertrophy and hyperplasia of the villi, along with increases in specific brush border membrane absorption mechanisms, such as glucose-sodium cotransport (via SGLT-1) and peptide transport (via Pep-T1). Currently, the best clinical markers of intestinal adaptation are the calculated percentage of enteral versus parenteral calories in a growing infant who has SBS and the serum concentrations of citrulline, an amino acid synthesized by mature enterocytes that has been used as a measure of functional intestinal mass.

Establishing norms for intestinal length in children

BACKGROUND

Existing data on pediatric intestinal length (IL) are limited because most studies report postmortem values. Using prospective data, appropriate norms for IL were developed.

METHOD

The IL measurements, using a silk suture on the antimesenteric border, were prospectively made on patients between 24 weeks of gestational age and 5 years of age undergoing laparotomy. Patients with gastrointestinal malformations or those above or below 2 SDs for growth parameters were excluded. A curve fitting process was applied to determine the best model for IL (small bowel and colon separately) from among postconception age, weight, and height at surgery.

RESULTS

One hundred eight patients participated in this study. Highly predictive (R(2) > 0.8) models for IL were determined for all predictor variables (postconception age, weight, and height) examined suggesting that all of these variables are excellent predictors determinants of IL. Although all models had statistically similar properties, the model using height had the best performance across the full range of the variable.

CONCLUSION

Although age, weight, nor height was definitely superior for the prediction of IL, we propose that until external validations of our models occur, height at surgery be used for the prediction of expected small intestinal and colon length in infants.

Short bowel syndrome: how short is too short?

Short bowel syndrome (SBS) is the most common cause of intestinal failure. This article discusses the prognostic factors that predict weaning from parenteral nutrition in SBS. The article also delineates an approach to enteral feeding in SBS.

A case of fetal midgut volvulus and jejunal atresia: nutritional support and maintenance of mucosal function and integrity

Fetal midgut volvulus is a quite rare disease. Here, we report a case of a preterm newborn with fetal peritonitis, jejunal atresia with volvulus of post-atresic small bowel since about 30 cm from ileo-cecal valve (ICV) followed by a not-used microileus and microcolon. The surgical intervention consisted in the resection of volvulated necrotic small bowel followed by primary anastomosis. After surgery, total parenteral nutrition (TPN) has been started since 16(th) of post-operative days when enteral feeding (EN) was administered with a lactose-free formula containing hydrolyzed protein and medium-chain triglycerides (Pregestimil). Re-establishing intestinal continuity was preferred rather than stoma that would have required TPN. In fact, re-operation could have led to a shorter residual small bowel (RSB), since the anastomosis was at 15 cm from ICV. Our study provides evidence that not only the type of procedure (enteral versus parenteral) of nutritional support, but also the type of milk may modify the outcome. Early EN should be encouraged in newborn abdominal surgical patients because it is associated with reduced complications.

Fgf9 signaling regulates small intestinal elongation and mesenchymal development

Short bowel syndrome is an acquired condition in which the length of the small intestine is insufficient to perform its normal absorptive function. Current therapies are limited as the developmental mechanisms that normally regulate elongation of the small intestine are poorly understood. Here, we identify Fgf9 as an important epithelial-to-mesenchymal signal required for proper small intestinal morphogenesis. Mouse embryos that lack either Fgf9 or the mesenchymal receptors for Fgf9 contained a disproportionately shortened small intestine, decreased mesenchymal proliferation, premature differentiation of fibroblasts into myofibroblasts and significantly elevated Tgfbeta signaling. These findings suggest that Fgf9 normally functions to repress Tgfbeta signaling in these cells. In vivo, a small subset of mesenchymal cells expressed phospho-Erk and the secreted Tgfbeta inhibitors Fst and Fstl1 in an Fgf9-dependent fashion. The p-Erk/Fst/Fstl1-expressing cells were most consistent with intestinal mesenchymal stem cells (iMSCs). We found that isolated iMSCs expressed p-Erk, Fst and Fstl1, and could repress the differentiation of intestinal myofibroblasts in co-culture. These data suggest a model in which epithelial-derived Fgf9 stimulates iMSCs that in turn regulate underlying mesenchymal fibroblast proliferation and differentiation at least in part through inhibition of Tgfbeta signaling in the mesenchyme. Taken together, the interaction of FGF and TGFbeta signaling pathways in the intestinal mesenchyme could represent novel targets for future short bowel syndrome therapies.

Early elective cesarean delivery before 36 weeks vs late spontaneous delivery in infants with gastroschisis

PURPOSE

The aim of this study is to assess the value of early elective cesarean delivery for patients with gastroschisis in comparison with late spontaneous delivery.

METHODS

Analysis of infants with gastroschisis admitted between 1986 and 2006 at a tertiary care center was performed. The findings were analyzed statistically.

RESULTS

Eighty-six patients were involved in the study. This included 15 patients who underwent emergency cesarean delivery (EM CD group) because of fetal distress and/or bowel ischemia. The remaining 71 patients born electively were stratified into 4 groups. The early elective cesarean delivery (ECD) group included 23 patients born by ECD before 36 weeks; late vaginal delivery (LVD) group included 23 patients who had LVD after 36 weeks; 24 patients had LCD after 36 weeks because of delayed diagnosis that resulted in late referral; and 1 patient had early spontaneous vaginal delivery (EVD group) before 36 weeks. The mean time to start oral feeding, incidence of complications, and primary closure were significantly better in the ECD group than in the LVD group. The duration of ventilation and the length of stay were shorter in ECD group, but the difference was not statistically significant.

CONCLUSION

Elective cesarean delivery before 36 weeks allows earlier enteral feeding and is associated with less complications and higher incidence of primary closure (statistically significant).

Clinical application and diagnostic yield of wireless capsule endoscopy in children

OBJECTIVE

The small bowel is anatomically difficult to examine and was investigated by invasive, indirect modalities, such as push enteroscopy and small bowel follow-through. The aim of this study was to assess the efficacy and clinical impact of wireless capsule endoscopy (WCE) in children.

MATERIALS AND METHODS

Over the last 3 years (2002-2005), 37 patients with suspected small-bowel disease were investigated with WCE at a median age of 11 years (range, 16 months-16 years). The indications for WCE was suspected Crohn's disease (CD) (18), obscure or occult gastrointestinal bleeding (7), polyposis syndromes (5), protein losing enteropathy (4), recurrent abdominal pain (2), and malabsorption syndrome (1). All patients had preceding upper gastrointestinal endoscopy (OGD), ileocolonoscopy, and 26 cases had a small bowel follow-through (SBFT). These results were compared with the findings on WCE.

RESULTS

Thirty-three (33) cases successfully completed the WCE through the small bowel. Four (4) patients were unable to swallow the capsule, 3 of which had to be placed in the duodenum endoscopically. In 3 patients, the capsule remained in the stomach and no small bowel images were obtained. The overall diagnostic yield was 85% (28/33 patients). The diagnostic findings included CD (13), source of gastrointestinal bleeding (7), polyposis syndromes (3), erosive enteropathy and patchy lymphangiectasia (4), and intussusception (1). WCE was found to be more sensitive for small bowel pathology than SBFT (20 vs. 6 [30% sensitivity, compared to WCE]) and endoscopic investigations (28 vs. 12 [43% sensitivity compared to WCE]). As a result of WCE findings, there was a positive alteration in the management in 28 of 33 (85%) cases.

CONCLUSIONS

WCE is a novel, noninvasive, and useful tool for the investigation of the small intestine in children. It is superior and more sensitive than other conventional endoscopic and radiologic investigations in the assessment of the small bowel. It can help in guiding surgical decisions and should be routinely integrated as a part of the diagnostic work-up of small bowel pathology.

Intestinal excretion of endogenous zinc in Guatemalan school children

The intestine is the major route of excretion of endogenous zinc (Zn) and has a key role in maintaining Zn homeostasis. The principal objective of this paper is to provide an interpretative report of quantities of endogenous fecal Zn (EFZ) excreted by rural Guatemalan school children fed either normal or low phytate maize as their principal food staple. EFZ was measured by a Zn stable isotope technique. EFZ did not differ between control and low phytate maize groups. The overall EFZ (n = 53) was (mean +/- SD) 1.56 +/- 0.69 mg Zn/d or 0.07 +/- 0.03 mg Zn x kg body wt(-1) x d(-1). EFZ was not correlated with the quantity of Zn absorbed. The estimated EFZ at the level of absorption that matched the physiologic requirement (EFZ(PR)) did not differ from the above mean value. The EFZ(PR) of 0.07 +/- 0.03 mg Zn/kg body wt is twice the value currently used in the estimation of Dietary Reference Intakes. Supported by other recent childhood data, these results suggest that the current estimates of EFZ(PR) used in the calculation of Zn requirements for children are misleadingly low.

Intestinal epithelial cell proliferation is dependent on the site of massive small bowel resection

Early intestinal adaptation after massive small bowel resection (SBR) is driven by increased epithelial cell (EC) proliferation. There is a clear clinical difference in the post-operative course of patients after the loss of proximal (P) compared to distal (D) small bowel. This study examined the effects of the site of SBR on post-resectional intestinal adaptation, and investigated the potential mechanisms involved. C57BL/6J mice (n = 7/group) underwent: (1) 60% P-SBR, (2) 60% D-SBR, (3) 60% mid (M)-SBR and (4) SHAM-operation (transection/reanastomosis). Mice were sacrificed at 7 days after surgery and ECs and adjacent mucosal lymphocytes (IELs) isolated. Adaptation was assessed in both jejunum and ileum by quantification of villus height, crypt depth, villus cell size, crypt cell size (microns), goblet cell number, and EC proliferation (%BrdU incorporation). Proliferation signalling pathways including keratinocyte growth factor (KGF)/KGFR(1), IL-7/IL-7R, and epidermal growth factor receptor (EGFR) were measured by RT-PCR. Expression of IL-7 was further analysed by immunofluorescence. Data were analyzed using ANOVA. All three SBR models led to significant increases in villus height, crypt depth, goblet cell numbers and EC proliferation rate when compared to respective SHAM groups. The strongest morphometric changes were found for jejunal segments after M-SBR and for ileal segments after P-SBR. Furthermore, morphometric analysis showed that at 1-week post-resection a tremendous increase in EC numbers occurred in jejunal villi (cell hyperplasia), whereas a significant increase in EC size predominated in ileal villi (cell hypertrophy). mRNA expression of KGF, KGFR(1), IL-7R, and EGFR showed a significant increase only after D-SBR, whereas IL-7 increased significantly after SBR in all investigated models, and this was confirmed by immunofluorescence studies. Early intestinal adaptation shows distinct differences depending on the site of SBR, and is predominately driven by cell hyperplasia in jejunal villi and cell hypertrophy in ileal villi. However, the exact mechanisms, which guide these signalling pathways are still unclear.

Nutritional management of infants with short bowel syndrome

The prevalence of short bowel syndrome appears to be increasing because of more aggressive surgical and medical approaches to the management of neonatal intraabdominal catastrophies. Hence, a large cohort of neonates with intestinal failure occupies neonatal intensive care units, requiring chronic total parenteral nutrition (TPN) in hopes that the residual bowel will adapt, thereby permitting weaning of TPN. Alternatively, when there is no hope for adaptation, these infants are maintained on TPN in hopes that they will grow to a size and state of general health satisfactory for either isolated intestinal transplant when liver function is preserved or combined liver-intestinal transplantation when the liver is irreparably damaged. Thus, it is imperative to provide enough parenteral nutrition to facilitate growth while minimizing TPN constituents predisposing to liver damage. Liver disease associated with intestinal failure (IFALD) seems to occur due to a variety of host factors combined with deleterious components of TPN. Host factors include an immature bile secretory mechanism, bile stasis due to fasting, and repeated septic episodes resulting in endotoxemia. Many constituents of TPN are associated with liver damage. Excessive glucose may result in fatty liver and/or hepatic fibrosis, excessive protein may lead to reduced bile flow, and phytosterols present in intravenous lipid may produce direct oxidant damage to the liver or may impede cholesterol synthesis and subsequent bile acid synthesis. Parenteral strategies employed to minimize TPN damage include reducing glucose infusion rates, reducing parenteral protein load, and reducing parenteral lipid load. Furthermore, preliminary studies suggest that fish oil-based lipid solutions may have a salutary effect on IFALD. Ultimately, provision of enteral nutrition is imperative for preventing or reversing IFALD as well as facilitating bowel adaptation. While studies of trophic hormones are ongoing, the most reliable current method to facilitate adaptation is to provide enteral nutrition. Continuous enteral feeding remains the mainstay of enteral nutrition support.

Wireless capsule endoscopy in children: a study to assess diagnostic yield in small bowel disease in paediatric patients

BACKGROUND AND AIM

Small bowel disease in the paediatric population is varied and to date has relied on indirect l modalities such as small bowel follow-through with attendant radiation exposure. Wireless capsule endoscopy (WCE) has the potential to provide a safer and more effective means of investigating the paediatric small bowel. The aim of our study was to prospectively assess the diagnostic yield of WCE compared with standard investigation in children with suspected small bowel disease.

METHODS

Twenty-eight consecutive patients, median age 12.5 y (range, 9.4-15.9) with suspected small bowel disease were investigated with WCE. This included 16 patients with suspected small bowel Crohn disease (CD) (10 newly diagnosed; 6 known cases), 6 with obscure or occult gastrointestinal bleeding (GIB), 3 with Peutz-Jegher polyposis (PJP), 2 with protein-losing enteropathy and 1 with recurrent abdominal pain. All of the patients had preceding upper gastrointestinal endoscopy (OGD) and ileocolonoscopy, and 24 had a barium meal and follow-through (BMFT). Images were downloaded and analysed and results compared with the endoscopic and radiological findings.

RESULTS

Three patients were unable to swallow the capsule (1 CD, 1 PJP and 1 GIB). Two of these patients (1 GIB, 1 PJP) had the capsule placed in the stomach endoscopically and completed the WCE uneventfully thereafter. In 3 patients (CD group) the capsule remained in the stomach and/or proximal duodenum and no small bowel images were obtained. Hence, 24 patients had successful completion of the WCE through the small bowel, 23 of whom had clinically relevant findings identified. In all patients with CD who had successful WCE studies (12/16), small bowel disease was identified (11/12 active disease, 1/12 chronic disease). A possible small bowel bleeding source was identified in all 6 patients with GIB. Two patients with GIB also underwent push enteroscopy and 1 of these had a bleeding source identified. The 2 patients with protein-losing enteropathy had extensive patchy lymphangiectasia of the jejunum and ileum, not detected at OGD. The patient with abdominal pain had an intussusception of the upper jejunum. The 2 PJP patients had small bowel polyps identified, which were not detected at BMFT. WCE was more sensitive for small bowel pathology than both BMFT (19 vs 5; 26% sensitivity compared with WCE) and endoscopic investigations (23 vs 10; 43.4% sensitivity compared with WCE). Two patients with CD had delayed capsule transit.

CONCLUSIONS

WCE led to a positive alteration in management in 18/24 (75%) of patients whose small bowel was examined by WCE and in 18/28 (64.3%) who were admitted to the study. WCE was safe, well tolerated, and more sensitive than radiological and standard endoscopic modalities in the detection of small bowel CD distribution, GIB source, and presence of polyps in children.

Gut responses to enteral nutrition in preterm infants and animals

Preterm birth is associated with immature digestive function that may require the use of total parenteral nutrition and special oral feeding regimens. Little is known about the responses to oral food in the preterm neonate and how enteral nutrients affect the immature gastrointestinal tract (GIT). In vivo studies are difficult to perform in laboratory rodents because of their small body size and that of immature organs at birth, and this makes the large farm animals (e.g., pigs, cattle, sheep) more attractive models in this field. In these species, preterm delivery at 88%-95% gestation is associated clinical complications and degrees of GIT immaturity similar to those in infants born at 70%-90% gestation. Studies in both animals and infants indicate that the immature GIT responds to the first enteral food with rapid increases in gut mass and surface area, blood flow, motility, digestive capacity, and nutrient absorption. To a large extent, the enteral food responses are birth independent, and can be elicited also in utero, at least during late gestation. Nevertheless, preterm neonates show compromised GIT structure, function, and immunology, particularly when delivered by caesarean section and fed diets other than mother's milk. Formula-fed preterm infants are thus at increased risk of developing diseases such as necrotizing enterocolitis, unless special care is taken to avoid excessive nutrient fermentation and bacterial overgrowth. The extent to which results obtained in preterm animals (most notably the pig) can be used to reflect similar conditions in preterm infants is discussed.

Changes in zinc absorption during development

Zinc (Zn) nutrition is of special practical importance in infants and young children, however relatively little is known about maturation and comparative aspects of Zn absorption. The principal objective of this paper is to compare Zn absorption of term infants, preterm infants, and adults on low phytate diets. Existing data derived from using Zn stable isotopes as extrinsic labels for an entire day were modeled with saturation kinetic analysis (saturable response model). When adjusted for differences in length of small intestine, the efficiency of Zn absorption for both term (4 months) and preterm (33 weeks post-conception) infants was comparable with that for adults, suggesting early maturation of mechanisms that regulate absorption. However, infant intestinal lengths were shorter, and Zn absorptive capacity was proportionately less. Reduced capacity was matched by lower Zn requirements for normal term infants. This favorable match, however, did not occur in the preterm infant because of relatively high Zn requirements. Although intestinal conservation of endogenous Zn in these preterm infants was appropriate in relation to the quantity of Zn absorbed, it was not optimal for achieving the retention required. Normal homeostatic mechanisms in the premature infant prevented efficient absorption of the quantity of Zn required or/and optimal conservation of endogenous Zn.

Diagnostic yield and clinical outcomes after capsule endoscopy in 100 consecutive patients with obscure gastrointestinal bleeding

OBJECTIVES

The endoscopic capsule is a useful tool for visualizing the small bowel in patients with obscure gastrointestinal bleeding. In this study the authors evaluated the diagnostic aid provided by the endoscopic capsule, the factors predicting a significant finding and their impact on the patients' clinical evolution.

METHODS

A total of 100 patients (52 men and 48 women, average age 64.4 years) underwent capsule endoscopy. Of this group, 52 patients presented with obscure-overt bleeding and 48 with obscure-occult bleeding. After an average follow-up time of 11.4 months, the clinical outcome was evaluated in 95 patients.

RESULTS

The endoscopic capsule identified significant findings in 68% of patients. The most common diagnosis (33.8%) was angiodysplasias. The most important factor predicting significant findings was the previous need for transfusion in the overt bleeding group. As the result of the findings, a specific intervention was made in 75.8% of patients. At the end of follow-up, the clinical outcome was considered positive in 71.6% of patients. Capsule retention occurred in one patient, who required surgery.

CONCLUSION

In patients with obscure gastrointestinal bleeding, capsule endoscopy provides a high degree of diagnostic aid. The best candidates for this procedure are patients with obscure-overt bleeding who have required blood transfusions. Capsule endoscopy has a positive influence on an important proportion of patients, whether oriented towards new diagnostic techniques or towards a definitive treatment.

Milestone in gastrointestinal endoscopy: double-balloon enteroscopy of the small bowel

The small bowel (SB) has been largely bypassed by flexible endoscopy because of inaccessibility. Push enteroscopy is now in the past, with recent innovations now making visualization of the SB possible. Wireless capsule endoscopy (CE) and double-balloon endoscopy (DBE) have been introduced. In this review, we focus on the diagnostic and therapeutic modalities of DBE, which may be a suitable replacement for push enteroscopy, preoperative endoscopy and to some extent of SB fall-through and CT scan. DBE is a new method of endoscopy developed and described by Yamamoto et al. in Jichi, Japan, in cooperation with Fujinon. Introduced to the market in 2003, it is possible with this endoscope to observe the entire SB in steps of 20-40 cm. Measuring the depth of insertion is also possible. Obscure gastrointestinal bleeding can be explained and treated in the majority of cases. Biopsy sampling, hemostasis, polypectomy, dilatation and tattoo are possible in the SB. Guidelines for FAB and Peutz-Jeghers syndrome will probably be reviewed in the next few years. The safety and efficacy of DBE have been demonstrated. DBE improves SB disease management and can substitute for more complex investigations. Additional data will come to light in years to come. Combining DBE with CE, CT/MRI enteroclysis in a new era for SB work-up and treatment is the likely future.

Small-Bowel Obstruction in a Phantom Model of ex Vivo Porcine Intestine: Comparison of PACS Stack and Tile Modes for CT Interpretation

PURPOSE

To compare computed tomographic (CT) image interpretation with picture archiving and communication systems (PACS) stack and tile modes for speed and accuracy of transition zone localization in small-bowel obstruction by using ex vivo porcine specimens.

MATERIALS AND METHODS

Twenty-five small-bowel obstruction phantom models made of ex vivo porcine intestines from a slaughterhouse were imaged at CT. One was used for observer training, and 24 were used for experimentation. At 20-cm intervals throughout the intestines, metallic markers were placed in the mesenteries immediately adjacent to bowel. One obstruction was made in each intestine, midway between markers, by ligating intestine with a 3-0 silk suture to simulate mechanical small-bowel obstruction. The lumen proximal to the ligation site was distended with air and a soybean oil-iodized oil mixture until at least two-thirds of the proximal intestine exceeded 2.0 cm in transverse diameter. Dilated segments were 310-550 cm in length. Soybean oil and a mixture of soybean and iodized oil were used to simulate differences in attenuation among bowel wall, intraluminal fluid, and extraluminal abdominal fat. Four experienced abdominal radiologists independently determined the transition zone by using stack mode (cine viewing of stacked images) and, at least 2 weeks later, tile mode (side-by-side image display). Accuracy and degree of error in counting markers were evaluated, and speed of interpretation was recorded. Statistical analysis was performed with the McNemar and Wilcoxon signed rank tests.

RESULTS

For all observers, accuracy of transition zone localization tended to be better with stack mode (63%-83% [15-20 phantoms]) than with tile mode (50%-63% [12-15 phantoms]), but the differences were not significant. For each observer, mean counting error was lower in stack mode (range, 0.96-2.48) than in tile mode (range, 1.74-3.22), with significance for three observers (P < .01, P < .01, and P = .04). Interpretation was significantly faster with stack mode by a factor of two to three for all observers (P < .01).

CONCLUSION

Stack mode evaluation for identification of the transition zone in obstructed small bowel is faster than evaluation with tile mode. Accuracy is not significantly different between modes, although there is a tendency toward better results with stack mode.

Is gastric ulceration different in normal and malnourished rats?

Protein malnutrition can adversely affect all tissues. The aim of the present study was to test the hypothesis that protein deprivation influences gastric ulcer formation, as well as metabolism and organ growth, in rats. In the present study, there was a significant reduction in the body and organ weight of rats fed a low-protein diet (P<0.001). Malnourished rats were less susceptible to ulceration of the gastric mucosa in ethanol and indomethacin models of acute gastric ulcers when compared with rats fed a normoproteic diet (17 % protein). Mucus production and prostaglandin E2 formation increased in malnourished rats, possibly explaining the lower number of acute ulcers in these animals. Pylorus ligature altered gastric juice composition (increased pH and gastric volume, and decreased total acid concentration) in the animal group fed a low-protein diet compared with the group fed a diet containing 17 % protein (P<0.05). The gastric mucosa was more damaged in malnourished rats than in normal rats evaluated for 14 d after acetic acid injection (P<0.001). Malnourished rats exhibited resistance to acute gastric lesions, owing to an increase in prostaglandin GE2 release and mucus secretion, which protected their gastric mucosa. This phenomenon was not seen in subchronic gastric ulceration.

Influence of changes in lactase activity and small-intestinal mucosal growth on lactose digestion and absorption in preterm infants

BACKGROUND

Feeding intolerance (ie, achieving and maintaining full enteral feedings) is a significant problem in preterm infants. A relation exists between feeding intolerance and incomplete lactose digestion.

OBJECTIVES

We sought to identify the factors relating to lactose digestion and absorption, lactase activity, and small-intestinal mucosal growth.

DESIGN

Lactose digestion and absorption, lactase-specific activity, and lumen-to-mucosa water flux as a measure of small-intestinal mucosal surface area were determined by using the triple-lumen perfusion technique on 2 occasions 3 wk apart in 10 preterm infants (x+/-SEM gestational age: 28.0+/-0.2 wk).

RESULTS

Lactose digestion and absorption and lactase activity doubled between studies (P=0.035 and P=0.041, respectively). The change in digestion and absorption was related to lactase activity (P=0.034, R2=0.38). Lactase activity correlated with gestational age at birth (P=0.012, R2=0.51). The number of days of feeding explained 80% of the variability in small-intestinal mucosal surface area (P=0.001).

CONCLUSIONS

To our knowledge, this is the first study to measure directly lactose digestion and absorption, lactase activity, and small-intestinal surface area in preterm infants. Changes in lactose absorption relate primarily to lactase activity rather than to mucosal growth. We showed directly a relation between enteral feeding and small-intestinal mucosal growth.

Children's susceptibility to chemicals: a review by developmental stage

Concerns about adequate protection of children's health from chemicals in the environment have created a need for research to identify how children's risks differ from adults'. A systematic review of factors that affect child sensitivity throughout development may be useful for research and practice in this area. We summarized available literature and other peer-reviewed information on factors that affect pharmacokinetics and exposure in an age-based developmental framework. Biological processes related to chemical absorption (gastrointestinal, dermal, and pulmonary), distribution, metabolism, and excretion were considered, along with reference to behaviors and other factors associated with child-specific exposures. The available information was summarized in a timeline of maturation for biological processes. It indicates variability in the duration and timing of maturation for each biological function. Possible implications for understanding pediatric sensitivity to environmental chemicals are discussed in light of factors affecting exposure through development. Themes that emerge from the evidence are presented as hypothesis-generating conclusions. This approach may be useful for evaluating developmental trends of susceptibility, and for identifying time periods and/or chemical classes of particular concern and thus important to consider in risk assessment.

Surgical therapy for short bowel syndrome

Patients with short bowel syndrome (SBS) suffer tremendous morbidity secondary to prolonged hospitalization and chronic parenteral nutrition (TPN). Overall, the majority of infants will adapt and ultimately become independent of TPN, but this process may require many months or years. Reasons for continued TPN dependency include bowel dysmotility, bacterial overgrowth, insufficient adaptation, or very short bowel length. It is this subpopulation of patients who may benefit from surgical procedures that optimize intestinal adaptation and increase the mucosal absorptive surface area. The goal of this review article is to summarize the process of intestinal adaptation and then to outline the surgical principles and techniques available to surgeons who treat this complicated group of patients.

Enterocyte metabolism during early adaptation after extensive intestinal resection in a rat model

OBJECTIVE

A better knowledge of intestinal adaptation after resection is required to improve the nutritional support that is given to patients. The aim of this study was to understand the metabolic changes underlying early adaptation after massive intestinal resection.

METHODS

Rats were assigned to either 80% intestinal resection or transection. All animals received the same intragastric nutrition. On day 8, plasma glutamine turnover was measured. Substrate use was determined on isolated enterocytes that were incubated in the presence of D-[U-(14)C] glucose (2 mmol/L), L-[U-(14)C] glutamine (2 mmol/L), L-[U-(14)C] arginine (1 mmol/L), or L-[1-(14)C] ornithine (1 mmol/L).

RESULTS

Plasma glutamine turnover was similar in both groups. The rate of enterocyte glutamine use was significantly increased in the resection group, although the maximal glutaminase activity was unchanged. Glutathione generation was enhanced 3-fold in remnant intestine as compared with transected intestine (P <.05). L-ornithine decarboxylation was increased markedly in resected animals (P <.05), without any detectable change of maximal ornithine decarboxylase activity.

CONCLUSION

The early phase of intestinal adaptation after resection induces changes in enterocyte glutamine and ornithine metabolism that may be related, in part, to increased de novo polyamine synthesis. This observation suggests that a supplementation of artificial nutrition by nutrients that lead to the generation of trophic agents may be of potential interest.

Enteral Drug Absorption in Patients with Short Small Bowel

Drug therapy may become difficult when a significant amount of the small intestine is resected, as happens in patients with a short small bowel. Drug absorption from the gastrointestinal tract is altered in these patients; however, this effect is variable in patients and differs with each drug. Literature regarding clinical outcomes of normal or alternative administration routes in patients with a short small bowel is limited. We explored what is written about the normal absorption of commonly used drugs and what difference the resection of different but substantial parts of the small intestine makes. Changes in the gastrointestinal tract after resection of >50% of the small intestine causes malabsorption of macronutrients and micronutrients, and may alter the drug absorption process. The metabolic activity of the abundantly present intestinal lactobacilli can also affect the enteral drug absorption in patients with short small bowel as this results in the production of lactic acid, gaseous CO(2), ethanol and an increased bile acid deconjugation. Accelerated intestinal luminal transit time causes a reduction in absorption of certain antimicrobial agents, digoxin, hydrochlorothiazide, ciclosporin, cimetidine, mesalazine (5-aminosalicylic acid), oral contraceptives and levothyroxine. Gastric hypersecretion and lack of sufficient contact time with the intestinal mucosa in patients with short small bowel leads to insufficient absorption of drugs such as omeprazole. Successful treatment with warfarin, tricyclic antidepressants, metronidazole, fluconazole, procainamide, sotalol and pindolol are reported in several studies. Many different factors cause this variability in drug absorption in such patients. Monitoring the serum drug concentration in these patients may ease dealing with the management problems.

Classification, epidemiology and aetiology

Intestinal failure and its most important cause, short-bowel syndrome (SBS), are rare clinical entities leading to a vast complex of symptoms and complications with significant morbidity and mortality. Both conditions occur as the result of a massive reduction in enteral nutrient absorptive capacity. Disease manifestation is based on aetiological and anatomical characteristics such as remaining intestinal length and the presence of a functionally intact colon. Congenital and perinatal conditions, for example, intestinal atresia, necrotizing enterocolitis (NEC) and intestinal volvulus are the most important causes in children. The aetiology in adults is based on diseases inducing loss of intestinal function or loss of intestinal surface area after extensive surgical resections. The most frequent causes are mesenteric infarction, radiation enteritis and Crohn's disease. Knowledge of the epidemiology of intestinal failure and SBS is limited, being mainly based on the extrapolated figures of home parenteral nutrition centres and single-centre studies. At present, the incidence of SBS is estimated to be 2-5 per million.

Wireless capsule endoscopy: a comparison with push enteroscopy in patients with gastroscopy and colonoscopy negative gastrointestinal bleeding

BACKGROUND

The development of wireless capsule endoscopy allows painless imaging of the small intestine. Its clinical use is not yet defined. The aim of this study was to compare the clinical efficacy and technical performance of capsule endoscopy and push enteroscopy in a series of 50 patients with colonoscopy and gastroscopy negative gastrointestinal bleeding.

METHODS

A wireless capsule endoscope was used containing a CMOS colour video imager, transmitter, and batteries. Approximately 50,000 transmitted images are received by eight abdominal aerials and stored on a portable solid state recorder, which is carried on a belt. Push enteroscopy was performed using a 240 cm Olympus video enteroscope.

RESULTS

Studies in 14 healthy volunteers gave information on normal anatomical appearances and preparation. In 50 patients with gastrointestinal bleeding and negative colonoscopy and gastroscopy, push enteroscopy was compared with capsule endoscopy. A bleeding source was discovered in the small intestine in 34 of 50 patients (68%). These included angiodysplasia (16), focal fresh bleeding (eight), apthous ulceration suggestive of Crohn's disease (three), tumour (two), Meckel's diverticulum (two), ileal ulcer (one), jejunitis (one), and ulcer due to intussusception (one). One additional intestinal diagnosis was made by enteroscopy. The yield of push enteroscopy in evaluating obscure bleeding was 32% (16/50). The capsule identified significantly more small intestinal bleeding sources than push enteroscopy (p<0.05). Patients preferred capsule endoscopy to push enteroscopy (p<0.001).

CONCLUSIONS

In this study capsule endoscopy was superior to push enteroscopy in the diagnosis of recurrent bleeding in patients who had a negative gastroscopy and colonoscopy. It was safe and well tolerated.

Small Intestinal Failure in Children

The treatment of children with intestinal failure should be predicated upon three overriding goals: 1) to keep the patient well nourished by parenteral nutrition (TPN), 2) to minimize the fecal loss of fluid, electrolytes, and nutrients, and 3) to enhance the natural process of intestinal adaptation whenever possible. The first goal is relatively easy to accomplish in the short- or intermediate-term, but difficult to accomplish for more than a few years because of recurrent septicemia, loss of venous access, and cholestatic liver disease. The risks of sepsis and loss of venous access can be minimized through meticulous central line care and the use of appropriate antibiotics when indicated. Cycling TPN and limiting parenteral protein intake sometimes ameliorates cholestasis. The second goal is only partially achievable regardless of the cause of intestinal failure. Fluid and electrolyte secretion often can be reduced but not normalized with antisecretory drugs. Bacterial overgrowth can be treated with the judicious use of antibiotics. The third goal generally can be accomplished only in a subpopulation of patients with surgically created short bowel. In these children, a satisfactory increase in surface area can occur only if nutrients are delivered directly into the bowel lumen. The trophic effects of glutamine, growth hormone, and other hormones remain to be universally accepted. Surgical bowel lengthening or bowel tapering can sometimes enhance intestinal function among patients with short bowel syndrome. If medical or nontransplantation surgical management of intestinal failure is unsuccessful, and the patient develops irreversible TPN-associated complications, transplantation of the intestine should be strongly considered.

Intestinal adaptation: structure, function, and regulation

After massive small bowel resection (SBR), the remnant intestine undergoes an adaptive process characterized by increases in wet weight, protein and DNA content, villus height and crypt depth, and absorptive surface area. These changes are the result of a proliferative stimulus that increases crypt cell mitosis and augments cellular progression along the villus axis. Functionally, there is upregulation of the Na(+)/glucose cotransporter, Na(+)/H(+) exchanger, and other enzymes involved in intestinal digestion and absorption. These physiologic events are a compensatory response to the sudden loss of digestive and absorptive capacity by the remnant intestine. A major consequence of inadequate intestinal adaptation is lifelong dependence on parenteral nutrition, which results ultimately in cholestatic liver dysfunction. Furthermore, adaptation may be associated with changes in intestinal permeability and an increased risk of bacterial translocation and sepsis. Several mediators thought to be integral to the postresection adaptive response have been proposed, including luminal nutrients, gastrointestinal secretions, and humoral factors. A thorough understanding of intestinal adaptation will be essential in the rational development of new and innovative therapies that amplify this complex but important process.

Enteral feeding of the micropremie

Clinical practice demands knowledge of gastrointestinal ontogeny and the factors that affect our ability to use enteral feeding in the micropremie. The decisions regarding milk type (when and how it should be given) are considered in the light of current physiologic and clinical evidence. Special considerations apply in the micropremie who is also small for gestational age and NEC must be avoided. Trophic feeding now has an established role, allowing the infant to benefit from enteral feeds even when full nutritive milk feeding is not possible.

Magnitude of functional adaptation after intestinal resection

Intestinal adaptation after resection has been much studied, but rarely examined in an integrative context. Hence we assessed the effects of resection and subsequent adaptation on the quantitative relationship between dietary glucose load and gut capacity to transport glucose. The ratio of capacity to load is termed the "safety factor." Our objectives were to determine 1) the time course of intestinal adaptation after resection, 2) whether adaptation is quantitatively complete, 3) whether survival requires maintaining a safety factor of at least 1.0 for glucose transport, 4) the effect of altered energy demands on adaptation, and 5) the relationship between the amount of tissue removed and the magnitude of functional adaptation. We performed 80% resection of the small intestine on Sprague-Dawley rats and measured small intestinal glucose uptake capacity, dietary glucose load, and gut gross morphology at 1, 5, and 10 wk postsurgery. Nearly all aspects of adaptation were complete by 1 wk postsurgery. After resection, remnant small intestine mass increased by over fivefold within 1 wk, to reach 50-70% of its preresection value. However, mass-specific glucose uptake activity was reduced, so that intestinal regeneration restored uptake capacity to only 33% of control values. Increased energetic demands had only modest effects on intestinal adaptation. Although the safety factor for small intestinal glucose uptake remained <1.0 (i.e., capacity < load) after adaptation to resection, nearly all rats survived. Hindgut fermentation of nonabsorbed nutrients appeared to contribute to that survival, despite inadequate small intestinal capacity. After less massive resection surgeries (25, 50, and 75% resections), the percent increase in glucose uptake capacity increased with the amount of tissue removed.

Limited ileal resection in infancy: the long-term consequences

BACKGROUND/PURPOSE

The longer-term sequelae of short bowel syndrome in infancy are reasonably well documented, but little is known about the long-term nutritional and metabolic effects of limited (less than 50 cm) ileal resection. This makes it difficult to formulate a rational follow-up policy in such children.

METHODS

All children who underwent limited ileal resection for either necrotizing enterocolitis (NEC) or intussusception at our institution between 1984 and 1992 were invited to attend a detailed clinical, anthropometric, hematologic, and biochemical assessment, together with a biliary and renal ultrasound scan and measurement of bone mineral density.

RESULTS

Twenty-four children (NEC, 17; intussusception, 7) of median age 7.4 years (range, 5.5 to 13.7 years) agreed to participate. Nine previously had undergone an isolated ileal resection, and 15 also had had variable lengths of colon removed. The length of resected ileum ranged from 3 to 44 cm, with a median of 10 cm. Seven control subjects in whom neonatal NEC developed but recovered without surgery were also evaluated. Median height, weight, and body mass index after ileal resection were between the 25th and 50th percentiles; no child was stunted or wasted. After ileal resection, one boy was found to have asymptomatic vitamin B12 deficiency, and three children had low plasma concentrations of vitamin A. Hematologic and biochemical parameters were otherwise normal apart from a few marginally low trace element levels in both subjects and controls. No renal calculi were detected, and bone mineral density measurements were normal in all except one child. Four children had cholelithiasis, all of whom had previously undergone limited ileal resection for NEC (two isolated, two ileocolic). Thus, the prevalence of cholelithasis after limited ileal resection for NEC was 24% at a median age of 7.0 years.

CONCLUSIONS

Growth and nutritional status are well preserved after limited ileal resection in infancy. Limited ileal resection for NEC is associated with a subsequent high prevalence of cholelithiasis and a risk of vitamin B12 deficiency. These findings are important when planning strategies for long-term follow-up.

Development of the human gastrointestinal tract: twenty years of progress

A combination of approaches has begun to elucidate the mechanisms of gastrointestinal development. This review describes progress over the last 20 years in understanding human gastrointestinal development, including data from both human and experimental animal studies that address molecular mechanisms. Rapid progress is being made in the identification of genes regulating gastrointestinal development. Genes directing initial formation of the endoderm as well as organ-specific patterning are beginning to be identified. Signaling pathways regulating the overall right-left asymmetry of the gastrointestinal tract and epithelial-mesenchymal interactions are being clarified. In searching for extrinsic developmental regulators, numerous candidate trophic factors have been proposed, but compelling evidence remains elusive. A critical gene that initiates pancreas development has been identified, as well as a number of genes regulating liver, stomach, and intestinal development. Mutations in genes affecting neural crest cell migration have been shown to give rise to Hirschsprung's disease. Considerable progress has been achieved in understanding specific phenomena, such as the transcription factors regulating expression of sucrase-isomaltase and fatty acid-binding protein. The challenge for the future is to integrate these data into a more complete understanding of the physiology of gastrointestinal development.

Effects of protein restriction in early life on growth and function of the gastrointestinal tract of the rat

BACKGROUND

Undernutrition during early life may have both immediate and later consequences. This study was undertaken to measure the long-term effects of perinatal undernutrition on the growth and function of the gastrointestinal tract.

METHODS

Pregnant rats were assigned to one of four groups that received isocaloric diets restricted in protein during pregnancy or lactation and during both or neither. Thereafter, their pups were followed until aged 1 year.

RESULTS

At 21 days the body weights of the young of those born of dams with postnatal protein restriction were halved, with comparable reductions in the weights of the stomach and caecum, compared with those of control animals. The lengths of the small and large intestines and mucosal weights of the foregut were also significantly reduced. Lactase activities were significantly increased and sucrase and maltase activities significantly reduced. By 42 days all the effects were less marked, and at 1 year the dimensions of the organs of the gastrointestinal tract and the composition and enzyme levels of the mucosa were all insignificantly different relative to body weight.

CONCLUSIONS

Prenatal protein restriction alone had no significant long-term negative effects on body weight, growth, or mucosal hydrolase activity of the gastrointestinal tract. Postnatal protein restriction had a marked effect on these indices in early life and delayed the changes in mucosal hydrolases usually seen at weaning. In contrast with other organs and their functions, long-term growth of the gut and activity of small intestinal hydrolases are preserved in the face of perinatal protein restriction.