Short bowel syndrome

ASPEN definitions in pediatric intestinal failure

Pediatric intestinal failure (PIF) is a relatively rare disease entity which requires focused interdisciplinary care and specialized nutrition management. There has long been a lack of consensus in the definition of key terms related to PIF due to its rarity and plethora of small studies rather than large trials. As such, the American Society for Parenteral and Enteral Nutrition (ASPEN) Pediatric Intestinal Failure Section, composed of clinicians from a variety of disciplines caring for children with intestinal failure, is uniquely poised to provide insight into this definition void. This document is the product of an effort by the Section to create evidence-based consensus definitions, with the goal of allowing for appropriate comparisons between clinical studies and measurement of longterm patient outcomes. This manuscript was approved by the ASPEN Board of Directors. This article is protected by copyright. All rights reserved.

Intestinal dysmotility after bowel resection in rats is associated with decreased ghrelin and vimentin expression and loss of intestinal cells of Cajal

This study provides novel insight into the mechanisms of intestinal dysmotility following massive small bowel resection. We show that 2 wk after bowel resection in rats, impaired intestinal motility was associated with loss of interstitial cells of Cajal (ICC; downregulation of transmembrane member 16A (TMEM16A) and c-kit expression) as well as with decreased vimentin, desmin, and ghrelin levels. Impaired intestinal motility led to a decrease in final body weight, suggesting less effective nutrient absorption. The purpose of this study was to evaluate the mechanisms of intestinal motility in a rat model of short bowel syndrome (SBS). Rats were divided into three groups: Sham rats underwent bowel transection; SBS-NSI rats underwent a 75% bowel resection and presented with normal intestinal size (NSI) at euthanasia and hypermotility patterns; SBS-DYS showed dysmotile (DYS) enlarged intestine and inhibited motility patterns. Animals were euthanized after 2 wk. Illumina's digital gene expression (DGE) analysis was used to determine the intestinal motility-related gene expression profiling in mucosal samples. Intestinal motility-related and ICC genes and protein expression in intestinal muscle layer were determined using real-time PCR, Western blotting, and immunohistochemistry. Gastrointestinal tract motility was studied by microcomputer tomography. From 10 Ca²⁺ signaling pathway-related genes, six genes in jejunum and seven genes in ileum were downregulated in SBS vs. Sham animals. Downregulation of TMEM16A mRNA and protein was confirmed by real-time PCR. Rapid intestinal transit time in SBS-NSI rats correlated with a mild decrease in TMEM16A, c-kit, and vimentin mRNA and protein expression (vs/. Sham animals). SBS-DYS rats demonstrated enlarged intestinal loops and delayed small intestinal emptying (on imaging studies) that were correlated with marked downregulation in TMEM16A, c-kit, vimentin, and ghrelin mRNA and protein levels compared with the other two groups. In conclusion, 2 wk following massive bowel resection in rats, impaired intestinal motility was associated with decreased vimentin and ghrelin gene and protein levels as well as loss of ICC (c-kit and TMEM16A).NEW & NOTEWORTHY This study provides novel insight into the mechanisms of intestinal dysmotility following massive small bowel resection. We show that 2 weeks after bowel resection in rats, impaired intestinal motility was associated with loss of interstitial cells of Cajal (downregulation of TMEM 16A, and c-kit expression) as well as with decreased vimentin, desmin, and ghrelin levels. Impaired intestinal motility led to decrease in final body weight, suggesting less effective nutrient absorption.

New Nutritional and Therapeutical Strategies of NEC

Necrotizing enterocolitis (NEC) is an acquired severe disease of the digestive system affecting mostly premature babies, possibly fatal and frequently associated to systemic complications. Because of the severity of this condition and the possible long-term consequences on the child's development, many studies have aimed at preventing the occurrence of the primary events at the level of the bowel wall (ischemia and necrosis followed by sepsis) by modifying or manipulating the diet (breast milk versus formula) and/or the feeding pattern (time for initiation after birth, continuous versus bolus feeding, modulation of intake according clinical events). Feeding have been investigated so far in order to prevent NEC. However, currently well-established and shared clinical nutritional practices are not available in preventing NEC. Nutritional and surgical treatments of NEC are instead well defined. In selected cases surgery is a therapeutic option of NEC, requiring sometimes partial intestinal resection responsible for short bowel syndrome. In this paper we will investigate the available options for treating NEC according to the Walsh and Kliegman classification, focusing on feeding practices in managing short bowel syndrome that can complicate NEC. We will also analyze the proposed ways of preventing NEC.

Creatine-loading preserves intestinal barrier function during organ preservation

We have developed a novel, intraluminal preservation solution that is tailored to the metabolic requirements of the intestine. This organ-specific solution addresses many of the problems associated with low temperature organ storage including energy, oxidative and osmotic stresses. However, conservation of energy levels remains one of the most difficult obstacles to overcome due to the inherent sensitivity of the mucosa to ischemia. Creatine-loading has become a popular and scientifically proven method of augmenting energy reserves in athletes performing anaerobic burst work activities. We hypothesized that if we could develop a method that was able to augment cellular energy levels, the structure and function of the mucosa would be more effectively preserved. The purpose of this study was to determine if creatine-loading is a feasible and effective strategy for preserving the intestine. Our data indicate that creatine loading has significant impact on energy levels during storage with corresponding improvements in mucosal structure and function. Both of our rodent models, a) continuous perfusion for 4 h and b) a single flush with our intraluminal preservation solution supplemented with 50 mM creatine, demonstrated significant improvements in creatine phosphate, ATP, Energy Charge and ATP/AMP following cold storage (P < 0.05). Notably, after 10 h creatine phosphate was 324% greater in Creatine-treated tissues compared to Controls (P < 0.05). Preferential utilization of glutathione in the Creatine group was effective at controlling oxidative injury after 10 h storage (P < 0.05). Improvements in barrier function and electrophysiology with creatine-treatment reflected superior mucosal integrity after 10 h storage; Permeability and Transepithelial resistance measurements remained at fresh tissue values. This was in stark contrast to Control tissues in which permeability rose to >300% of fresh tissue values (P < 0.005) and transepithelial resistance dropped by 95% (P < 0.005). After 10 h storage, Park's grading of histologic injury reflected extensive villus denudation (grade 4) in control tissues compared to healthy tissue (grade 0) in the Creatine group. This study demonstrates that a strategy of creatine supplementation of our intraluminal preservation solution facilitates the preservation of the intestinal mucosa during storage.

Bile salt dependent lipase promotes intestinal adaptation in rats with massive small bowel resection

Intestinal adaptation is important for the short bowel syndrome (SBS) patients. Growing evidence has suggested that bile salt dependent lipase (BSDL) not only has the lipolytic activity, but also the immune-modulating and pro-proliferative activities. The purpose of the present study was to investigate the effects of BSDL on intestinal adaptive growth and gut barrier function in a rat model of SBS. Twenty-four male Sprague-Dawley rats were randomly divided into three experimental groups: sham group (rats underwent bowel transection and re-anastomosis), SBS group (rats underwent 80% bowel resection), SBS-BSDL group (SBS rats orally administered BSDL). The animals were weighed daily. The intestinal morpho-histochemical changes and intestinal barrier function were determined 14 days after the operations. Meanwhile, the expressions of Wnt signaling molecules in enterocytes were also analyzed by immunohistochemistry and Western blot. The postoperative weight gain was faster in the SBS rats treated with BSDL than in the SBS/untreated group. The SBS rats treated with BSDL had significantly greater villus height, crypt depth, and enterocyte proliferation in their residual intestines, as compared with the SBS/untreated group. The recovery of intestinal barrier function was promoted and the expressions of tight-junction proteins were increased in the SBS rats treated with BSDL. Additionally, the data indicated that the proadaptive activities of BSDL might be mediated by Wnt signaling activation in the enterocytes. These observations suggested that enteral BSDL administration promoted intestinal adaptive growth and barrier repairing by activating Wnt signaling pathway in SBS rats.

Nephrolithiasis as a common urinary system manifestation of inflammatory bowel diseases; a clinical review and meta-analysis

CONTEXT

The extra-intestinal manifestations of inflammatory bowel disease (IBD) are common and involve other organs or systems for example; urinary system.

EVIDENCE ACQUISITIONS

For this review, we used a variety of sources by searching through Web of Science, PubMed, EMBASE, Scopus and directory of open access journals (DOAJ).

RESULTS

Urinary complications may occur in up to 22% of patients and nephrolithiasis or renal/kidney stones have been suggested to be a common manifestation of disease in forms of uric acid, calcium phosphate or calcium oxalate. We performed a meta-analysis on five clinical trials and reported that correlation between IBD and formation of stone in renal system is positive and significant (Fix-effect model; CI: 95%, P <0.001, and randomeffect model; CI: 95%, P = 0.03).

CONCLUSIONS

Based on the reports of the clinical trials, calcium oxalate is more prevalent in Crohn's disease (CD) than in ulcerative colitis (UC).

Small bowel in vivo bioengineering using an aortic matrix in a porcine model

OBJECTIVE

To evaluate the feasibility of an in vivo small bowel bioengineering model using allogeneic aortic grafts in pigs.

BACKGROUND

The best treatment for short bowel syndrome is still unclear. Intestinal transplantation, as well as lifelong parenteral nutrition is associated with a 5-year survival rate of less than 50 %. We have already used allogeneic arterial segments to replace the upper airway in sheep. The results were encouraging with an induced transformation of the aortic wall into tracheo-bronchial bronchial-type tissue.

METHODS

Seven young mini-pigs were used. A 10-cm-diameter, allogeneic, aortic graft was interposed in an excluded small bowel segment and wrapped by the neighboring omentum. Animals were autopsied at 1 (n = 2), 3 (n = 3), and 6 months (n = 2), respectively. Specimens were examined macroscopically and microscopically.

RESULTS

The overall survival rate of the animals was 71.4 %. No anastomotic leak occurred. Histologic analysis revealed intestinal-like wall transformation of the aortic graft in the surviving animals.

CONCLUSION

Aortic-enteric anastomosis is feasible in a porcine model. Moreover, in vivo, bioengineered, intestinal-like transformation of the vascular wall was identified.

Management of short bowel syndrome in infancy

Short bowel syndrome (SBS) is a reduction in functioning bowel length which is most often a result of surgical resection. Risk factors in the neonatal period include necrotising enterocolitis, small bowel atresia and gastroschisis. With increasing survival of preterm infants there is an increase in incidence. Management is dependent on the use of parenteral nutrition to maintain fluid and electrolyte homeostasis and promote growth and development with the longer term aim being to promote intestinal adaptation to achieve partial or complete enteral autonomy. In this review we discuss the incidence, aetiology, pathophysiology, medical and surgical treatments and outcome.

Dietary supplementation with vitamin D stimulates intestinal epithelial cell turnover after massive small bowel resection in rats

PURPOSE

While the endocrine action of the active metabolite 1,25-dihydroxyvitamin D (VtD) has been well characterized in relation to the maintenance of plasma calcium and phosphate homeostasis through regulation of intestinal absorption, recent research has focused on its autocrine and/or paracrine activities. Such activities have been best characterized in intestine, where VtD regulates cell differentiation and maturation. The purpose of this study was to evaluate the effect of VtD on enterocyte turnover in a rat model of short bowel syndrome (SBS).

METHODS

Male rats were divided into four groups: sham rats underwent bowel transection, sham-VtD rats underwent bowel transection and were treated oral VtD, SBS rats underwent a 75 % bowel resection, and SBS-VtD rats underwent bowel resection and were treated with VtD. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's digital gene expression (DGE) analysis was used to determine VtD pathway-related gene expression profiling. VtD receptor (VDR) and its promoter, Bax and Bcl-2 mRNA expression were determined using real-time PCR. Western blotting was used to determine p-ERK, Bax and β-catenin protein levels.

RESULTS

From the total of 20,000 probes, 11 genes related to VtD signaling were investigated. Of these genes, five were found to be up-regulated in SBS versus sham animals with a relative change in gene expression level of 20 %, five remained unchanged, and one was down-regulated. VtD treatment in sham and SBS rats resulted in significant up-regulation of the VDR gene and its promoter's expression. SBS-VtD rats demonstrated a significant increase in all intestinal mucosal parameters compared to SBS animals. A significant increase in cell proliferation in SBS-VtD rats was accompanied by increased β-catenin protein levels. A significant decrease in cell apoptosis in this group was correlated with lower Bax/Bcl-2 mRNA and protein levels.

CONCLUSION

In a rat model of SBS, dietary supplementation with VtD stimulates enterocyte turnover, which correlates with up-regulated VtD receptor expression in the remaining small intestine.

Where are we at with short bowel syndrome and small bowel transplant

Intestinal failure can be defined as the critical reduction of functional gut mass below the minimal amount necessary for adequate digestion and absorption to satisfy body nutrient and fluid requirements in adults or children. Short bowel syndrome (SBS) is characterized by a state of malabsorption following extensive resection of the small bowel. SBS may occur after resection of more than 50% and is certain after resection of more than 70% of the small intestine, or if less than 100 cm of small bowel is left. Several treatment modalities other than total parenteral nutrition, including hormones (recombinant human growth hormone, glucagon-like peptide-2) and tailoring surgeries (Bianchi procedure, serial transverse enteroplasty), had been proposed, however these were either experimental or inefficient. Small bowel transplant is a rather new approach for SBS. The once feared field of solid organ transplantation is nowadays becoming more and more popular, even in developing countries. This is partially secondary to the developments in immunosuppressive strategy. In this regard, alemtuzumab deserves special attention. There are more complex surgeries, such as multivisceral transplantation, for multi-organ involvement including small bowel. This latter technique is relatively new when compared to small bowel transplant, and is performed in certain centers worldwide. In this review, an attempt is made to give an insight into small bowel syndrome, small bowel transplantation, and related issues.

TGF-β affects enterocyte turnover in correlation with TGF-β receptor expression after massive small bowel resection

OBJECTIVES

In the present study, we evaluated the effect of transforming growth factor-beta 2 (TGF-β2)-enriched diet on enterocyte turnover and correlated it with TGF-β2 receptor expression along the villus-crypt axis in a rat model of short bowel syndrome (SBS).

METHODS

CaCo-2 cells were incubated with increasing concentrations of TGF-β2. Alamar Blue reduction test was used for investigation of cell viability and evaluation of cell apoptosis was assessed by flow cytometry. Male rats were divided into 4 groups: Sham rats underwent bowel transection, Sham TGF-β rats were treated with diet enriched with TGF-β2, SBS rats underwent a 75% bowel resection, and SBS TGF-β rats were fed a diet enriched with TGF-β2 after bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. TGF-β2r expression in villus tips, lateral villi and crypts was assessed by immunohistochemistry. The effect of TGF-β2 on enterocyte turnover for each compartment was evaluated in correlation with TGF-β2r expression.

RESULTS

Incubation of CaCo-2 cells with TGF-β2 resulted in a significant decrease in cell viability and increased cell apoptosis. TGF-β2r expression in crypts increased in SBS rats (vs sham) and was accompanied by decreased cell proliferation and increased cell apoptosis following TGF-β2 administration. A significant decrease in TGF-β2r expression at villous tips in SBS rats was accompanied by a decreased cell apoptosis in this compartment following exposure to TGF-β2-enriched diet.

CONCLUSIONS

In a rat model of SBS, the inhibiting effect of TGF-β2 on enterocyte turnover correlates with TGF-β2 receptor expression along the villus-crypt axis.

Oral insulin stimulates intestinal epithelial cell turnover following massive small bowel resection in a rat and a cell culture model

PURPOSE

We have recently reported that oral insulin (OI) stimulates intestinal adaptation after bowel resection and that OI enhances enterocyte turnover in correlation with insulin receptor expression along the villus-crypt axis. The purpose of the present study was to evaluate the effect of OI on intestinal epithelial cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS) and in a cell culture model.

METHODS

Caco-2 cells were incubated with increasing concentrations of insulin. Cell proliferation and apoptosis were determined by FACS cytometry. Cell viability was investigated using the Alamar Blue technique. Male rats were divided into three groups: Sham rats underwent bowel transection, SBS rats underwent a 75% bowel resection, and SBS-OI rats underwent bowel resection and were treated with OI given in drinking water (1 U/ml) from the third postoperative day. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined on day 15. Real time PCR was used to determine the level of bax and bcl-2 mRNA and western blotting was used to determine bax, bcl-2, p-ERK and AKT protein levels. Statistical analysis was performed using the one-way ANOVA test, with P < 0.05 considered statistically significant.

RESULTS

Treatment of Caco-2 cells with insulin resulted in a significant increase in cell proliferation (twofold increase after 24 h and 37% increase after 48 h) and cell viability (in a dose-dependent manner), but did not change cell apoptosis. In a rat model of SBS, treatment with OI resulted in a significant increase in all parameters of intestinal adaptation. Elevated cell proliferation rate in insulin treated rats was accompanied by elevated AKT and p-ERK protein levels. Decreased cell apoptosis in SBS-INS rats corresponded with a decreased bax/bcl-2 ratio.

CONCLUSIONS

Oral insulin stimulates intestinal epithelial cell turnover after massive small bowel resection in a rat model of SBS and a cell culture model.

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.

Bilirubin impairs intestinal regrowth following massive small bowel resection in a rat model

OBJECTIVES

The purpose of the present study was to evaluate the effects of exogenous bilirubin on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS).

MATERIALS AND METHODS

Male Sprague-Dawley rats were divided into 5 experimental groups: Sham rats underwent bowel transection and reanastomosis, sham multiple doses of bilirubin (MDB) rats underwent bowel transection and were treated with bilirubin, SBS rats underwent a 75% small bowel resection, SBS-SDB (single dose bilirubin) rats underwent a bowel resection and were treated with a single dose of bilirubin, and SBS-MDB underwent a bowel resection and were treated with 3 doses of bilirubin. Bilirubin was administered intraperitoneally from the 7th day through the 14th day postoperatively. Serum total bilirubin concentration over time was evaluated in 5 SBS-SDB rats following a single intraperitoneal dose. Total bilirubin, alanine aminotransferase, and aspartate aminotransferase in serum and parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15.

RESULTS

SBS-SDB and SBS-MDB animals demonstrated lower ileal bowel and mucosal weights, jejunal mucosal DNA and ileal mucosal protein, and jejunal and ileal villus height and crypt depth (vs SBS animals). Bilirubin-treated rats showed a lower apoptotic index in jejunum and ileum and a trend toward an increase in cell proliferation in jejunum and ileum (vs SBS group).

CONCLUSIONS

In a rat model of SBS, exogenous bilirubin inhibits structural intestinal adaptation. Increased cell proliferation and decreased apoptosis may be considered adaptive mechanisms that maintain cell mass.

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.

Peptide YY induces enterocyte proliferation in a rat model with total enteral nutrition after distal bowel resection

The main reason why enterocyte proliferative effects of peptide YY (PYY) have not been detected in rats undergoing massive small intestinal resection after feeding may have been the background activity of markedly increased endogenous PYY released from L cells in the distal gut in response to the intraluminal nutrients. The purpose of the present study was to evaluate the effects of PYY on enterocyte proliferation in a rat model of distal bowel resection (DBR) with total enteral nutrition (TEN). Male, adult Sprague-Dawley rats were assigned into three experimental groups: sham rats underwent bowel transection and reanastomosis, DBR rats underwent the resection of 40 cm distal small intestine and colon, and DBR-PYY rats underwent distal bowel resection as above, and were treated with PYY(1-36) from day 2 to day 14 postoperatively. During days 2-14 postoperatively, all animals received isocaloric TEN. At the endpoints, plasma PYY levels and parameters of enterocyte proliferation were determined. Compared with the sham group, DBR rats demonstrated a significant decrease in plasma PYY levels, and a significant increase in intestinal bowel and mucosal weight, mucosal DNA and protein content, villus height and crypt depth, and crypt cell proliferation index. Administration of PYY (DBR-PYY group) led to a significant increase in plasma PYY levels, intestinal bowel and mucosal weight, mucosal DNA and protein content, villus height and crypt depth, and crypt cell proliferation index in comparison with the DBR untreated group. We conclude that administration of PYY increases the plasma PYY levels, and PYY induces enterocyte proliferation with TEN after distal bowel resection.

Current issues in the management of intestinal failure

Successful long term parenteral nutrition has transformed the prognosis for children with irreversible intestinal failure in the last three decades, but has also highlighted the long term complications: intestinal failure associated liver disease; recurrent catheter sepsis; and impaired venous access. Recent advances in small bowel transplantation and non-transplant surgical techniques now offer hope of sustained survival in the future without parenteral nutrition.

Effect of leptin on intestinal re-growth following massive small bowel resection in rat

Recent evidence suggests that the adipose tissue-derived cytokine leptin (LEP) is involved in modulation of growth and differentiation of normal small intestine. The purpose of the present study was to evaluate the effects of parenteral LEP on structural intestinal adaptation, cell proliferation and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and re-anastomosis, SBS-rats underwent a 75% small bowel resection, and SBS-LEP-rats underwent bowel resection and were treated with LEP given subcutaneously at a dose of 20 mug/kg, once daily, from day 3 through 14. Parameters of intestinal adaptation (bowel and mucosal weights, mucosal DNA and protein, villus height and crypt depth in jejunum and ileum), enterocyte proliferation and enterocyte apoptosis were determined on day 15 following operation. Ileal tissue samples were taken for detection of bax and bcl-2 gene expression using RT-PCR technique. Statistical analysis was performed using the non-parametric Kruskal-Wallis ANOVA test, with P<0.05 considered statistically significant. Treatment with subcutaneous LEP resulted in a significant increase in jejunal (17%, P<0.05) and ileal (13%, P<0.05) bowel weight, jejunal (10%, P<0.05) and ileal (25%, P<0.05) mucosal weight, jejunal (26%, P<0.05) and ileal (38%, P<0.05) mucosal DNA, ileal (25%, P<0.05) mucosal protein, jejunal (41%, P<0.05) and ileal (21%, P<0.05) villus height, jejunal (37%, P<0.05) crypt depth, and jejunal (24%, P<0.05) and ileal (21%, P<0.05) enterocyte proliferation compared to SBS-animals. Enterocyte apoptosis increased significantly after bowel resection in jejunum and ileum compared to sham animals and was accompanied by an increased bax gene expression and a decreased bcl-2 gene expression in ileal samples. SBS-LEP rats showed a trend toward a decrease in enterocyte apoptosis in ileum and a mild decrease in bax gene expression compared to SBS-untreated animals. In conclusion, in a rat model of SBS parenteral LEP stimulates structural intestinal adaptation. Increased cell proliferation and decreased cell death via apoptosis may be responsible for this increased cell mass.

Advances in short bowel syndrome: an updated review

Short bowel syndrome (SBS) continues to be an important clinical problem due to its high mortality and morbidity as well as its devastating socioeconomic effects. The past 3 years have witnessed many advances in the investigation of this condition, with the aim of elucidating the cellular and molecular mechanisms of intestinal adaptation. Such information may provide opportunities to exploit various factors that act as growth agents for the remaining bowel mucosa and may suggest new therapeutic strategies to maintain gut integrity, eliminate dependence on total parenteral nutrition, and avoid the need for intestinal transplantation. This review summarizes current research on SBS over the last few years.

Parenteral arginine impairs intestinal adaptation following massive small bowel resection in a rat model

The nitric oxide precursor L-arginine (ARG) has been shown to influence intestinal structure and absorptive function. It is also well known that the route of administration modulates the effects of ARG. The present study evaluated the effects of parenteral ARG on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and reanastomosis, SBS rats underwent a 75% small bowel resection, and SBS-ARG rats underwent a 75% small bowel resection and were treated with ARG given subcutaneously at a dose of 300 mug/kg, once daily, from days 3 to 14. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15 following operation. The SBS rats demonstrated a significant increase in jejunal and ileal bowel and mucosal weight, villus height and crypt depth, and cell proliferation index compared with the sham group. The SBS-ARG animals demonstrated lower ileal bowel and mucosal weights, jejunal mucosal DNA and ileal mucosal protein, and jejunal and ileal villus height and crypt depth compared with SBS animals. The SBS-ARG rats also had a lower cell proliferation index in both jejunum and ileum and a greater enterocyte apoptotic index in ileum compared with the SBS-untreated group. In conclusion, in a rat model of SBS, parenteral arginine inhibits structural intestinal adaptation. Decreased cell proliferation and increased apoptosis are the main mechanisms responsible for decreased cell mass.

Effect of subcutaneous insulin on intestinal adaptation in a rat model of short bowel syndrome

Insulin has been shown to influence intestinal structure and absorptive function. The purpose of the present study was to evaluate the effects of parenteral insulin on structural intestinal adaptation, cell proliferation, and apoptosis in a rat model of short bowel syndrome (SBS). Male Sprague-Dawley rats were divided into three experimental groups: sham rats underwent bowel transection and reanastomosis, SBS rats underwent a 75% small bowel resection, and SBS-INS rats underwent a 75% small bowel resection and were treated with insulin given subcutaneously at a dose of 1 U/kg, twice daily, from day 3 through day 14. Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 15 following operation. SBS rats demonstrated a significant increase in jejunal and ileal bowel and mucosal weight, villus height and crypt depth, and cell proliferation index compared with the sham group. SBS-INS animals demonstrated higher jejunal and ileal bowel and mucosal weights, jejunal and ileal mucosal DNA and protein, and jejunal and ileal crypt depth compared with SBS animals. SBS-INS rats also had a greater cell proliferation index in both jejunum and ileum and a trend toward a decrease in enterocyte apoptotic index in jejunum and ileum compared with the SBS untreated group. In conclusion, parenteral insulin stimulates structural intestinal adaptation in a rat model of SBS. Increased cell proliferation is the main mechanism responsible for increased cell mass.

The effects of long-term total parenteral nutrition on gut mucosal immunity in children with short bowel syndrome: a systematic review

BACKGROUND: Short bowel syndrome (SBS) is defined as the malabsorptive state that often follows massive resection of the small intestine. Most cases originate in the newborn period and result from congenital anomalies. It is associated with a high morbidity, is potentially lethal and often requires months, sometimes years, in the hospital and home on total parenteral nutrition (TPN). Long-term survival without parenteral nutrition depends upon establishing enteral nutrition and the process of intestinal adaptation through which the remaining small bowel gradually increases its absorptive capacity. The purpose of this article is to perform a descriptive systematic review of the published articles on the effects of TPN on the intestinal immune system investigating whether long-term TPN induces bacterial translocation, decreases secretory immunoglobulin A (S-IgA), impairs intestinal immunity, and changes mucosal architecture in children with SBS. METHODS: The databases of OVID, such as MEDLINE and CINAHL, Cochran Library, and Evidence-Based Medicine were searched for articles published from 1990 to 2001. Search terms were total parenteral nutrition, children, bacterial translocation, small bowel syndrome, short gut syndrome, intestinal immunity, gut permeability, sepsis, hyperglycemia, immunonutrition, glutamine, enteral tube feeding, and systematic reviews. The goal was to include all clinical studies conducted in children directly addressing the effects of TPN on gut immunity. RESULTS: A total of 13 studies were identified. These 13 studies included a total of 414 infants and children between the ages approximately 4 months to 17 years old, and 16 healthy adults as controls; and they varied in design and were conducted in several disciplines. The results were integrated into common themes. Five themes were identified: 1) sepsis, 2) impaired immune functions: In vitro studies, 3) mortality, 4) villous atrophy, 5) duration of dependency on TPN after bowel resection. CONCLUSION: Based on this exhaustive literature review, there is no direct evidence suggesting that TPN promotes bacterial overgrowth, impairs neutrophil functions, inhibits blood's bactericidal effect, causes villous atrophy, or causes to death in human model.The hypothesis relating negative effects of TPN on gut immunity remains attractive, but unproven. Enteral nutrition is cheaper, but no safer than TPN. Based on the current evidence, TPN seems to be safe and a life saving solution.

Growth hormone and epidermal growth factor upregulate specific sodium-dependent glutamine uptake systems in human intestinal C2BBe1 cells

Glutamine (Gln) is one of the major oxidative fuels of the enterocyte and enters from the lumen via Na(+)-dependent transport mechanisms. When given parenterally, growth hormone (GH) + epidermal growth factor (EGF) increase apical Gln uptake after massive enterectomy in rabbits. Although both receptors are basolateral, GH and EGF are present in luminal contents. We hypothesized that short-term luminal growth factor exposure to enterocytes increases apical Gln uptake by selective upregulation of systems A, B(0,+), or ASC+B(0). A monolayer of C2(BBe)1 cells was exposed for 10 or 60 min to GH (500 microg/L), EGF (100 microg/L), both, or neither. Initial uptake of [(3)H]Gln (50 micromol/L) was measured in the presence of Na(+) or choline. The contributions of systems A, B(0,+), and ASC+B(0) were determined by competitive inhibition with arginine and/or alpha-(methylamino)butyric acid. Gln uptake was linear for up to 8 min. Na(+)-independent transport was negligible. Under control conditions the relative contributions of systems A, B(0,+), and ASC+B(0) were 0, 19 +/- 6, and 80 +/- 4%, respectively. GH alone had no effect on Gln transport. After 10 min of EGF exposure, Na(+)-dependent Gln uptake increased by 50% (P < 0.001) with no change in individual transport systems. Combined EGF and GH for 60 min increased Gln transport by system B(0,+) nearly 250% (P < 0.001) and system A from undetectable levels to 16% of total transport (P < 0.01). Thus, short-term luminal exposure to EGF+GH increases Na(+)-dependent Gln transport mainly by upregulating system B(0+).

Evaluation of the outcomes of short bowel syndrome and indications for intestinal transplantation

Long-term parenteral nutrition (PN) and intestinal transplantation (IT) are life-saving therapies for patients with short bowel syndrome (SBS). However, indications and timing of these therapies are controversial. In this study we aimed to evaluate the indications for IT. Forty-two patients, each with <100 cm of small bowel, were divided into three groups according to the length of remnant: group I patients (n = 18): colon plus 50 to 100 cm of small bowel (SB); group II patients (n = 14): colon plus <50 cm of SB; and group III patients (n = 10): <50 cm of SB without colon. One-year mortality rates for groups I, II, and III were 50%, 72%, and 100%, respectively. All group I survivors developed intestinal adaptation, returning to regular oral feedings at 1 year. Interestingly, three of four surviving patients in group II developed adaptation and were fed an oral short bowel diet (SBD) at 1 year. None of the group III patients survived >1 year, dying due to multiorgan failure in the early postoperative period or from sepsis within 1 year. We conclude that patients with a very short bowel are candidates for IT when stable. If the colon is intact, however, regardless of small bowel remnant length, the patient should be given a chance to develop intestinal adaptation before making the decision for permanent PN or IT.

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.

Effect of dietary fat on early morphological intestinal adaptation in a rat with short bowel syndrome

Among factors promoting mucosal hyperplasia after bowel resection, long-chain fatty acids may have a special role. The purpose of the present study was to evaluate the effects of high-fat diet (HFD) on early intestinal adaptation in rats with short bowel syndrome (SBS). Male Sprague-Dawley rats underwent either a bowel transection with re-anastomosis (Sham rats) or 75% small bowel resection (SBS rats). Animals were randomly assigned to one of three groups: Sham rats fed normal chow (Sham-NC); SBS rats fed NC (SBS-NC); and SBS rats fed HFD (SBS-HFD). Rats were killed on days 3 or 14. Body weight and parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) were determined at time of killing. By day 3, SBS-HFD rats demonstrated higher duodenal and jejunal bowel and mucosal weights and ileal villus height and jejunal crypt depth vs SBS-NC rats. By day 14 SBS-HFD rats continued to demonstrate increased duodenal and jejunal bowel weight and duodenal mucosal weight vs SBS-NC animals. We conclude that early exposure to HFD both augmented and accelerated structural bowel adaptation in a rat model of SBS.

Irreversible intestinal failure

Intestinal failure (IF) can be defined as the reduction of functional gut mass below the minimal amount necessary for digestion and absorption adequate to satisfy the nutrient and fluid requirements for maintenance in adults or growth in children. In developed countries, IF mainly includes individuals with the congenital or early onset of conditions requiring protracted or indefinite parenteral nutrition (PN). Short bowel syndrome was the first commonly recognized cause of protracted IF. The normal physiologic process of intestinal adaptation after extensive resection usually allows for recovery of sufficient intestinal function within weeks to months. During this time, patients can be sustained on parenteral nutrition. Only a few children have permanent intestinal insufficiency and life-long dependency on PN. Non-transplant surgery including small bowel tapering and lengthening may allow weaning from PN in some cases. Hormonal therapy with recombinant human growth hormone has produced poor results while therapy with glucagon-like peptide-2 holds promise. Congenital diseases of enterocyte development such as microvillus inclusion disease or intestinal epithelial dysplasia cause permanent IF for which no curative medical treatment is currently available. Severe and extensive motility disorders such as total or subtotal intestinal aganglionosis (long segment Hirschsprung disease) or chronic intestinal pseudo-obstruction syndrome may also cause permanent IF. PN and home-PN remain are the mainstays of therapy regardless of the cause of IF. Some patients develop complications while receiving long-term PN for IF especially catheter related complications (thrombosis, sepsis) and liver disease. These patients may be candidates for intestinal transplantation. This review discusses the causes of irreversible IF and emphasizes the specific medico-surgical strategies for prevention and treatment of these conditions at several stages of IF.

Low-fat diet impairs postresection intestinal adaptation in a rat model of short bowel syndrome

BACKGROUND

Low-fat diets (LFD) are utilized frequently in patients with short bowel syndrome (SBS). The purpose of this study was to investigate the effects of LFD on intestinal adaptation, enterocyte proliferation, and enterocyte cell death in a rat model of SBS.

METHODS

Adult male Sprague-Dawley rats were divided into 3 experimental groups: Sham-NC rats underwent bowel transection and reanastomosis and were fed normal chow (NC), SBS-NC rats underwent 75% small bowel resection and were fed NC, and SBS-rats were fed a low-fat diet (SBS-LFD). Parameters of intestinal adaptation, enterocyte proliferation, and enterocyte apoptosis were determined on day 14 after operation.

RESULTS

SBS-NC rats showed a significant increase (v Sham-NC) in jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth. A significant 67% increase in crypt cell proliferation rate and 265% increase in villus enterocyte apoptosis was seen in the ileum of SBS-NC rats compared with control animals (P <.05). SBS-LFD animals showed lower ileal mucosal weight (29%; P <.05), jejunal crypt depth (20%; P <.05), and ileal villus height (21%; P <.05). A significant decrease in villus apoptosis in jejunum (74%; P <.05) and ileum (67%; P <.05) and a decrease in cell proliferation in ileum (35%; P <.05) was seen also after exposure to LFD compared with SBS-NC.

CONCLUSIONS

In a rat model of SBS, early LFD appears to inhibit parameters of intestinal adaptation. A possible mechanisms for this effect may be decreased cell proliferation. Decreased enterocyte loss via apoptosis, found in this study, may reflect a reduced number of enterocyte.

Endotoxemia inhibits intestinal adaptation in a rat model of short bowel syndrome

Sepsis is commonly associated with or complicates short bowel syndrome (SBS). The purpose of the present study was to investigate the effects of endotoxemia on intestinal adaptation in a rat model of SBS. Male Sprague-Dawley rats were divided into three experimental groups: Sham rats underwent bowel transection and re-anastomosis, SBS rats underwent 75% small bowel resection, and SBS-LPS rats underwent bowel resection and were given lipopolysaccharide. Bowel weight, organ weights, and parameters of intestinal adaptation (bowel and mucosal weights, mucosal DNA and protein, villus height, and crypt depth) were determined on day 15 following operation. The results of this study demonstrate that SBS rats showed a significant increase (vs. Sham) in jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth. SBS-LPS animals demonstrated lower (vs. SBS rats) final body weight (215 +/- 7 vs. 287 +/- 10 g, P < 0.05), overall weight in duodenum (98+/- 2 vs. 119 +/-5 mg/cm, P < 0.05) and jejunum (144 +/- 9 vs. 189 +/- 16 mg/cm, P < 0.05), mucosal weight in jejunum (54 +/- 5 vs. 69 +/- 5 mg/cm, P < 0.05) and ileum (31 +/- 2 vs. 37 +/- 3 mg/cm, P < 0.05), mucosal DNA in jejunum (89 +/- 11 vs. 120 +/- 11 microg/cm, P < 0.05) and ileum (46 +/- 6 vs. 61 +/- 4 microg/cm, P < 0.05), jejunal crypt depth (152 +/- 19 vs. 189 +/- 12 microm, P < 0.05), and ileal villus height (405 +/- 63 vs. 515 +/- 30 pm, P < 0.05). In addition, the SBS group had no late (second week) mortality, whereas the SBS-LPS group had an 17% late mortality rate. In conclusion, in a rat model of SBS-LPS, endotoxemia appears to inhibit structural intestinal adaptation and increase mortality.

Effect of transforming growth factor-alpha on intestinal adaptation in a rat model of short bowel syndrome

OBJECTIVE

TGF-alpha has recently been shown to stimulate enterocyte proliferation. In the present study we investigated the effect of TGF-alpha on enterocyte proliferation and loss via apoptosis and its effects on intestinal adaptation in a rat following massive bowel resection.

METHODS

Male Sprague-Dawley rats underwent bowel transection and reanastomosis (sham group) or 75% small bowel resection and anastomosis (SBS group) and were treated with intraperitoneal TGF-alpha (75 microg/kg) from the ninth postoperative day (SBS-TGF-alpha group). Parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth), enterocyte proliferation, and apoptosis were determined on day 15. Statistical significance was determined by ANOVA with a P < 0.05 considered significant.

RESULTS

SBS-TGF-alpha rats demonstrated a significant increase (vs SBS) in duodenal, jejunal, and ileal overall bowel and mucosal weights; ileal mucosal DNA and protein; and jejunal and ileal villus height. SBS-TGF-alpha rats also showed an increased cell proliferation index in jejunum (704 +/- 43 vs 499 +/- 63 BrdU-positive cells/10 crypts, P < 0.05) and ileum (715 +/- 84 vs 529 +/- 40 BrdU-positive cells/10 crypts, P < 0.05) and decreased apoptotic index in ileum (8.7 +/- 1.1 vs 21.8 +/- 3.2 apoptotic cells/1,000 villus cells, P < 0.05) compared to SBS animals.

CONCLUSIONS

In a rat model of SBS, TGF-alpha enhances intestinal adaptation. Possible mechanisms may include increased cell proliferation and decreased enterocyte loss via apoptosis.

Nutritional management of short bowel syndrome in adults

Short bowel syndrome (SBS) comprises the sequelae of nutrient, fluid, and weight loss that occurs subsequent to greatly reduced functional surface area of the small intestine. Signs and symptoms of SBS include electrolyte disturbances; deficiencies of calcium, magnesium, zinc, iron, vitamin B12, or fat-soluble vitamin deficiency; malabsorption of carbohydrates, lactose, and protein; metabolic acidosis, gastric acid hypersecretion; formation of cholesterol biliary calculi and renal oxalate calculi; and dehydration, steatorrhea, diarrhea, and weight loss. Thorough nutritional management is the key factor in achieving an optimal outcome in SBS. Total parenteral nutrition is necessary in the early stages, as is replacement of excess fluid and electrolyte losses. Nutritional management of SBS has traditionally been divided into three phases: an acute phase when total parenteral nutrition is usually begun, an adaptation phase, and a maintenance phase. Recommendations regarding the need for parenteral nutrition vary depending on the presence or absence of certain factors: the ileocecal valve, jejunum, and functional colon. Patients with residual small bowel length of 100 cm or less usually require the administration of parenteral nutrition at home with good results. The total parenteral nutrition diet should consist of a majority of calories from fat, followed by protein, and the remaining as carbohydrates. Vitamins, minerals, and trace elements should also be added accordingly. Although total parenteral nutrition is initially necessary, treatment goals should focus on early transition to enteral nutrition followed by oral feeds. Other recent advances in the medical management of SBS include pharmacologic treatment and the use of specific nutrients and growth factors to stimulate intestinal absorption and adaptation. Both animal studies and clinical trials in humans have shown much promise in supplementation with growth factors and hormones. This strategy is likely to play a greater role in the treatment of SBS in the future.

Parenteral nutrition-associated liver complications in children

Parenteral nutrition is a life-saving therapy for patients with intestinal failure. It may be associated with transient elevations of liver enzyme concentrations, which return to normal after parenteral nutrition is discontinued. Prolonged parenteral nutrition is associated with complications affecting the hepatobiliary system, such as cholelithiasis, cholestasis, and steatosis. The most common of these is parenteral nutrition-associated cholestasis (PNAC), which may occur in children and may progress to liver failure. The pathophysiology of PNAC is poorly understood, and the etiology is multifactorial. Risk factors include prematurity, long duration of parenteral nutrition, sepsis, lack of bowel motility, and short bowel syndrome. Possible etiologies include excessive caloric administration, parenteral nutrition components, and nutritional deficiencies. Several measures can be undertaken to prevent PNAC, such as avoiding overfeeding, providing a balanced source of energy, weaning parenteral nutrition, starting enteral feeding, and avoiding sepsis.

Acute renal failure and metabolic disturbances in the short bowel syndrome

BACKGROUND

Short bowel syndrome (SBS) describes a malabsorptive state caused by extensive loss of small intestinal length.

AIM

To improve understanding of the metabolic complications of SBS.

DESIGN

Observational study of five patients with SBS who presented with acute renal failure.

RESULTS

Acute renal failure in our patients was predominantly due to salt and fluid depletion, and sepsis. Electrolyte imbalance was a major cause of morbidity. Metabolic acidosis was seen in three patients, and may arise from excessive gastrointestinal bicarbonate loss, compounded by impaired renal homeostasis. Our patients also manifested disturbances of calcium and magnesium homeostasis.

DISCUSSION

Patients with SBS are at high risk of renal failure. Prevention of this complication requires close monitoring and the maintenance of sodium homeostasis through increased intake and measures to reduce loss (e.g. anti-motility agents and large bowel re-anastomosis), and calcium, magnesium and vitamin D supplementation.