Effects of dietary linoleic acid on mucosal adaptation after small bowel resection

Liver injury after small bowel resection is prevented in obesity-resistant 129S1/SvImJ mice

Intestinal failure-associated liver disease is a major morbidity associated with short bowel syndrome. We sought to determine if the obesity-resistant mouse strain (129S1/SvImJ) conferred protection from liver injury after small bowel resection (SBR). Using a parenteral nutrition-independent model of resection-associated liver injury, C57BL/6J and 129S1/SvImJ mice underwent a 50% proximal SBR or sham operation. At postoperative week 10, hepatic steatosis, fibrosis, and cholestasis were assessed. Hepatic and systemic inflammatory pathways were evaluated using oxidative markers and abundance of tissue macrophages. Potential mechanisms of endotoxin resistance were also explored. Serum lipid levels were elevated in all mouse lines. Hepatic triglyceride levels were no different between mouse strains, but there was an increased accumulation of free fatty acids in the C57BL/6J mice. Histological and serum markers of hepatic fibrosis, steatosis, and cholestasis were significantly elevated in resected C57BL/6J SBR mice as well as oxidative stress markers and macrophage recruitment in both the liver and visceral white fat in C57BL/6J mice compared with sham controls and the 129S1/SvImJ mouse line. Serum endotoxin levels were significantly elevated in C57BL/6J mice with significant elevation of hepatic TLR4 and reduction in PPARα expression levels. Despite high levels of serum lipids, 129S1/SvImJ mice did not develop liver inflammation, fibrosis, or cholestasis after SBR, unlike C57BL/6J mice. These data suggest that the accumulation of hepatic free fatty acids as well as increased endotoxin-driven inflammatory pathways through PPARα and TLR4 contribute to the liver injury seen in C57BL/6J mice with short bowel syndrome.NEW & NOTEWORTHY Unlike C57BL/6 mice, the 129S1/SvImJ strain is resistant to liver inflammation and injury after small bowel resection. These disparate outcomes are likely due to the accumulation of hepatic free fatty acids as well as increased endotoxin-driven inflammatory pathways through PPARα and TLR4 in C57BL/6 mice with short bowel syndrome.

Effects of high-fat diet on liver injury after small bowel resection

BACKGROUND

The optimal regimen for enteral nutritional support in the management of children with short bowel syndrome (SBS) is not well characterized. A high fat, enteral diet is theoretically beneficial due to increased caloric density and enhanced structural adaptation. We therefore sought to determine the long-term effects of a high fat diet (HFD) on liver injury, a common complication of SBS, compared to a standard chow (SC) diet.

METHODS

Using a parenteral nutrition-independent model of resection-associated liver injury, C57BL/6 mice underwent a sham operation or a 50% or 75% proximal small bowel resection (SBR). Mice in each group were then fed either a HFD (35% kcal fat) or SC (13% kcal fat). At post-operative week 15, markers of liver injury were quantified.

RESULTS

Liver triglyceride levels were increased from 7- to 19-fold in mice on the HFD compared to mice fed SC in the sham, 50%, and 75% resection groups. Serum ALT (2.2-fold increase in 75% resected mice compared to sham controls) and AST (2.0- and 2.7-fold increases in 50% and 75% resected mice, respectively) levels as well as fibrotic liver staining were elevated only in resected mice fed a HFD.

CONCLUSION

Long-term enteral feeding of HFD in our murine SBS model is associated with hepatic steatosis and liver injury. Our observation that liver steatosis and injury occur independent of parenteral nutrition suggests that enteral feeding composition and magnitude of intestinal loss may make a significant contribution to intestinal failure-associated liver disease.

Dissecting Target Toxic Tissue and Tissue Specific Responses of Irinotecan in Rats Using Metabolomics Approach

As an anticancer agent, irinotecan (CPT-11) has been widely applied in clinical, especially in the treatment of colorectal cancer. However, its clinical use has long been limited by the side effects and potential tissue toxicity. To discriminate the target toxic tissues and dissect the specific response of target tissues after CPT-11 administration in rats, untargeted metabolomic study was conducted. First, differential metabolites between CPT-11 treated group and control group in each tissue were screened out. Then, based on fold changes of these differential metabolites, principal component analysis and hierarchical cluster analysis were performed to visualize the degree and specificity of the influences of CPT-11 on the metabolic profiles of nine tissues. Using this step-wise method, ileum, jejunum, and liver were finally recognized as target toxic tissues. Furthermore, tissue specific responses of liver, ileum, and jejunum to CPT-11 were dissected and specific differential metabolites were screened out. Perturbations in Krebs cycle, amino acid, purine and bile acid metabolism were observed in target toxic tissues. In conclusion, our study put forward a new approach to dissect target toxic tissues and tissue specific responses of CPT-11 using metabolomics.

Early enteral fat supplementation improves protein absorption in premature infants with an enterostomy

BACKGROUND

Early enteral fat supplementation and fish oil (FO) stimulates post-resection intestinal adaptation in rats and increases fat absorption in premature infants with bowel resection and an enterostomy.

OBJECTIVE

To test the hypothesis that early fat supplement and FO increases post-resection protein absorption, intestinal RNA, protein without decreasing intestinal arachidonic acid (AA) in premature infants with an enterostomy.

METHODS

36 premature infants (<2 months old) with an enterostomy after surgical treatment for necrotizing enterocolitis or spontaneous intestinal perforation who tolerated enteral feeding at 20 ml/kg/day were randomized to usual care (control, n = 18) or early supplementing enteral Microlipid (ML) and FO (treatment, n = 18). Intralipid was decreased as the dose of enteral fat was increased. Daily weight, ostomy output and nutritional intake were recorded. Weekly 24-hour ostomy effluent was collected to measure fecal protein. Protein absorption was calculated by subtracting fecal protein from dietary protein. Tissue samples from the functional stoma and the nonfunctional distal diverted end were collected during bowel reanastomosis to measure RNA, protein, and fatty acid (FA) profile.

RESULTS

Compared to controls, the treatment group had higher protein absorption (g/kg/day) and intestinal RNA and protein (μg/mg tissue) proximal to the ostomy. The two groups had similar FA profiles except that the treatment group had higher n-3 eicosapentaenoic acid (EPA, μg/mg tissue) proximal to the ostomy.

CONCLUSION

Early supplementation of enteral ML and FO to premature infants with an enterostomy increased dietary protein absorption, intestinal RNA, protein and n-3 EPA content without altering other FA content.

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.

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.

Effects of dietary fish oil on intestinal adaptation in 20-day-old weanling rats after massive ileocecal resection

Long chain polyunsaturated fatty acids (LCPUFA)seem to be the most trophic macronutrients in inducing intestinal adaptation in adult short bowel syndrome (SBS), although their effects on intestinal adaptation in infants with SBS remain unknown.It is hypothesized that a high fat diet enriched with n-3 LCPUFA derived from fish oil (FO) will increase intestinal adaptation compared with a diet dominated by n-6 PUFA from corn oil (CO) in weanling SBS rats after massive ileocecal resection (ICR). Twenty-day-old rats were sorted into four groups, CO-sham, FO-sham,CO-ICR, and FO-ICR groups, and fed ad lib with the CO or FO diet, respectively, for 7 d after sham or ICR surgery. Compared with CO-ICR rats, FO-ICR rats consumed less diet per gram of weight gain, had less diarrhea and fecal fat excretion, and demonstrated a tendency toward better weight gain. The mucosal mass, DNA and RNA levels of the colon and RNA levels of the distal jejunum, and the colonic mucosal area (%) were significantly higher in FO-ICR rats than in CO-ICR rats. These results suggest that the beneficial effect of dietary FO is associated with better adaptation in the colon in weanling rats after ICR.

Intestinal adaptation following massive ileocecal resection in 20-day-old weanling rats

OBJECTIVE

Few infant animal models have been used to study infantile short bowel syndrome (SBS). Most SBS models involve removal of the proximal small bowel followed by jejunoileal anastomosis, which has unclear clinical relevance to human infantile SBS that often results from surgical treatment for necrotizing enterocolitis and involves removal of the ileum, ileocecal valve, and part of or the entire colon. Our objective was to develop a more appropriate SBS model in developing rats.

MATERIALS AND METHODS

Twenty-day-old weanling rats were divided into 2 surgery groups, ileocecal resection (ICR) and sham groups, and a control group that did not undergo surgery. All were fed a liquid diet ad libitum for 7 days after surgery or for 7 days in the controls, and body weight, food intake, and stool changes were recorded daily. The rats were then euthanized and intestinal lengths and weights were recorded. Samples of intestine from the distal jejunum and proximal colon were collected for histology. Mucosal samples from the middle, distal jejunum, and colon were collected for measurements of mucosal weights, DNA, RNA, and protein levels. Maltase activity was determined in the small intestine.

RESULTS

Eighty-five percent of rats survived the ICR with subsequent development of diarrhea, hyperphagia, and poor growth. Adaptive responses to ICR, as compared with sham, were evidenced by increased intestinal and mucosal weights, DNA, RNA, and protein levels, increased maltase activity and villous thickness in distal jejunum, and increased mucosal thickness in the colon.

CONCLUSIONS

This ICR model in weanling rats is appropriate for studying human infantile SBS.

Dietary palmitic acid modulates intestinal re-growth after massive small bowel resection in a rat

PURPOSE

Among factors promoting intestinal adaptation after bowel resection, dietary fatty acids have a special role. The purpose of the present study was to evaluate the effects of palmitic acid (PA) on early intestinal adaptation in rats with short bowel syndrome (SBS).

MATERIALS

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 four groups: sham rats fed normal chow (sham-NC); SBS rats fed NC (SBS-NC), SBS rats fed high palmitic acid diet (SBS-HPA), and SBS rats fed low palmitic acid diet (SBS-LPA). Rats were sacrificed on day 14. Parameters of intestinal adaptation, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, cell proliferation and apoptosis were determined at sacrifice. RT-PCR and Western blotting were used to determine the level of bax and bcl-2 mRNA and protein (parameters of apoptosis), and ERK protein levels (parameter of proliferation). Statistical analysis was performed using Kruskal-Wallis test followed by post hoc test for multiple comparisons with P values of less than 0.05 considered statistically significant.

RESULTS

SBS-HFD rats demonstrated higher bowel and mucosal weight, mucosal DNA and protein in ileum, while deprivation of PA (SBS-LPA) inhibited intestinal re-growth both in jejunum and ileum compared to SBS-NC rats. A significant up-regulation of ERK protein coincided with increased cell proliferation in SBS-HFD rats (vs. SBS-NC). Also, the initial decreased levels of apoptosis corresponded with the early decrease in bax and increase in bcl-2 at both mRNA and protein levels.

CONCLUSION

Early exposure to HPA both augments and accelerates structural bowel adaptation in a rat model of SBS. Increased cell proliferation and decreased cell apoptosis may be responsible for this effect. Deprivation of PA in the diet inhibits intestinal re-growth.

Congenital short bowel syndrome: a case report and review of the literature

Congenital short bowel syndrome (SBS) is a rare condition of the newborn, with several reports demonstrating high mortality. A six-week-old boy presented with chronic diarrhea and failure to thrive. An upper gastrointestinal endoscopy showed a straight duodenum, and multiple small bowel biopsies were histologically normal. An upper gastrointestinal series showed malrotation. At laparotomy, the small bowel was 50 cm in length, confirming the diagnosis of congenital SBS. Parenteral nutrition was initiated and enteral feeding with an amino acid-based formula containing long-chain fatty acids was introduced early and gradually advanced. At the last follow-up examination at 24 months, he was thriving on a regular diet, with normal growth and development. Long-term survival of children with congenital SBS is now possible if enteral feeds are introduced early to promote intestinal adaptation, with subsequent weaning off parenteral nutrition.

Use of percutaneous endoscopic gastrostomy or percutaneous endoscopic jejunostomy in short bowel syndrome

Patients who have short bowel syndrome (SBS) and concomitant intestinal failure have insufficient functional capacity to absorb sufficient nutrients, electrolytes, and/or fluid to sustain independent life. As such, these patients require specialized nutritional support. Although parenteral nutrition is often necessary, at least initially, the therapeutic goal should be to enhance intestinal adaption and enteral nutrient assimilation, and thereby reduce parenteral nutrition requirements. The induction of hyperphagia is critical. Enteral intake also can be enhanced through enteric tube feeding. There are, however, insufficient data to recommend the universal use of a peptide-based formula (versus a polymeric formula), although the use of such a formula may be considered in individual patients in whom the clinician has compared nutritional outcome with the two types of formulas.

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.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

Intestinal adaptation after massive intestinal resection

Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation.

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.

Enteral and parenteral nutrition in the care of patients with short-bowel syndrome

Short-bowel syndrome is a challenging entity for the gastroenterologist, requiring integration of medical, nutritional, surgical and psychological therapies. Treatment must be based on the patient's age, remaining gastrointestinal anatomy, baseline nutritional status and underlying general health as well as the numerous complications which may arise. This chapter reviews physiological alterations that occur with short-bowel syndrome and how therapies can be tailored to most adequately meet the needs of these patients. Emphasis on early stages of therapy to enhance intestinal adaptation is focused on as management during this time has a significant impact on the long-term outcome of these patients.

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.

Effect of a high fat diet on lipid absorption and fatty acid transport in a rat model of short bowel syndrome

Long chain fatty acids (LCFAs) appear to be powerful stimulants for small bowel adaptation in patients with short bowel syndrome (SBS). However, the dietary lipid content may alter intestinal lipid transport. The aim of this study was to investigate the effects of a high fat diet (HFD) on in vivo lipid absorption and molecular and cellular mechanisms of LCFAs uptake by the remaining bowel. Male Sprague-Dawley rats (240-280) 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). SBS rats underwent a 75% small bowel resection. Rats were sacrificed on day 3 or 14. Body weight, fat intake and fat clearance (total fecal fat) were measured twice a week. Fat absorbability was calculated as intake minus clearance and was expressed as percent of intake. Total RNA from the mucosa of duodenum, jejunum and ileum was extracted using TRIZOL Reagent. Northern blot analysis was performed to determine FAT/CD36 mRNA levels. Enterocyte LCFA transport was measured on day 14. LCFA uptake was determined by measuring cellular [3H]-oleate uptake over time (4-120 s). Mean (+/-SE) FAT/CD36 mRNA levels and oleate uptake kinetic parameters were analyzed using ANOVA. Fat absorbability diminished after bowel resection, suggesting fat malabsorption. Remaining bowel in SBS-NC rats responded by an increase in FAT/CD36 mRNA levels in the duodenum and ileum on day 3, and the duodenum and jejunum on day 14 compared to sham-NC animals, and was accompanied by an increase in enterocyte LCFA transport in all segments. Exposure to a HFD for 14 days resulted in significantly increased fat absorbability after 3 days compared to SBS-NC rats. However, FAT/CD36 mRNA levels (vs. SBS-NC) decreased in all segments on day 3. On day 14, FAT/CD36 mRNA levels were decreased in the duodenum and ileum and were accompanied by reduced oleate uptake by isolated enterocytes in the ileum (vs. SBS-NC). In a rat model of SBS, early high fat diet increased lipid absorptive capacity of the intestinal remnant as seen by increased fat absorbability. The main mechanisms of this effect may be an acceleration of structural intestinal adaptation resulting in an increased number of enterocytes. However, at molecular and cellular levels HFD decreased mucosal FAT/CD36 mRNA levels and oleic acid uptake by isolated enterocytes.

Enhancing bowel adaptation in short bowel syndrome

Malabsorption of both nonessential and essential nutrients, fluid, and electrolytes will, if not compensated for by increased intake, lead to diminished body stores and to subclinical and eventually clinical deficiencies. By definition, intestinal failure prevails when parenteral support is necessary to maintain nutritional equilibrium. After intestinal resection, adaptation, a progressive recovery from the malabsorptive disorder, may be seen. Research has focused on optimizing remnant intestinal function through dietary or pharmacologic interventions. In this review, factors responsible for the morphologic and functional changes in the adaptive processes are described. Results of clinical trials employing either growth hormone and glutamine or glucagon-like peptide-2 in short bowel patients are presented.

Interactions between nutrients and peptide growth factors in intestinal growth, repair, and function

Several lines of evidence demonstrate that general nutritional status, specific nutrients (eg, zinc, glutamine), and certain trophic growth factors (eg, growth hormone, insulin-like growth factor I, keratinocyte growth factor, and glucagon-like peptide-2) have important interactions relevant for intestinal growth and function. Adequate nutritional status is critical for endogenous growth factor synthesis in the gut and other tissues and is an important mediator of organ responsiveness to exogenous growth factor administration. Both endogenously synthesized and exogenously administered growth factors upregulate nutrient uptake and utilization by gut mucosa, skeletal muscle, and other organs. Emerging data from both animal and human studies indicate that combinations of selected growth factors and specific nutrients may improve the growth, adaptation, and repair of the intestinal mucosa. Additional studies to determine basic mechanisms of nutrient-growth factor interactions and the safety and efficacy of treatment with combinations of specific nutrients and recombinant growth factors are needed. Results of these investigations should define new methods for support of the intestinal tract during short bowel syndrome (SBS), catabolic illness, and malnutrition.