A new treatment for patients with short-bowel syndrome. Growth hormone, glutamine, and a modified diet

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.

Comparative effects of glucagon-like peptide-2 (GLP-2), growth hormone (GH), and keratinocyte growth factor (KGF) on markers of gut adaptation after massive small bowel resection in rats

BACKGROUND

Administration of specific growth factors exert gut-trophic effects in animal models of massive small bowel resection (SBR); however, little comparative data are available. Our aim was to compare effects of a human glucagon-like peptide-2 (GLP-2) analog, recombinant growth hormone (GH) and recombinant keratinocyte growth factor (KGF) on jejunal, ileal, and colonic growth and functional indices after 80% SBR in rats.

METHODS

Thirty-seven male rats underwent small bowel transection (sham operation) with s.c. saline administration (control; Tx-S; n = 7) or 80% midjejuno-ileal resection (Rx) and treatment with either s.c. saline (Rx-S, n = 7), GLP-2 at 0.2 mg/kg/d (Rx-GLP-2; n = 8), GH at 3.0 mg/kg/d (Rx-GH; n = 8), or KGF at 3.0 mg/kg/d (Rx-KGF; n = 7) for 7 days. All groups were pair-fed to intake of Rx-S rats. Gut mucosal cell growth indices (wet weight, DNA and protein content, villus height, crypt depth, and total mucosal height) were measured. Expression of the cytoprotective trefoil peptide TFF3 was determined by Western blot. Gut mucosal concentrations of the tripeptide glutathione (L-glutamyl-L-cysteinyl-glycine) and glutathione disulfide (GSSG) were measured by high-performance liquid chromatography and the glutathione/GSSG ratio calculated.

RESULTS

SBR increased adaptive growth indices in jejunal, ileal, and colonic mucosa. GLP-2 treatment increased jejunal villus height and jejunal total mucosal height compared with effects of resection alone or resection with GH or KGF treatment. Both GH and KGF modestly increased colonic crypt depth after SBR. SBR did not affect small bowel or colonic goblet cell number or TFF3 expression; however, goblet cell number and TFF3 expression in both small bowel and colon were markedly up-regulated by KGF treatment and unaffected by GLP-2 and GH. SBR oxidized the ileal and colonic mucosal glutathione/GSSG redox pools. GLP-2 treatment after SBR increased the glutathione/GSSG ratio in jejunum, whereas KGF had an intermediate effect. In addition, GLP-2 (but not GH or KGF) prevented the SBR-induced oxidation of the glutathione/GSSG pools in both ileum and colon.

CONCLUSIONS

GLP-2 exerts superior trophic effects on jejunal growth and also improves mucosal glutathione redox status throughout the bowel after massive SBR in rats. Both GH and KGF increase colonic mucosal growth in this model. KGF alone potently increases gut mucosal goblet cell number and expression of the cytoprotective trefoil peptide TFF3. The differential effects of GLP-2, GH and KGF administration in this model of short bowel syndrome suggest that individual therapy with these growth factors may not be an adequate strategy to maximally improve adaptive gut mucosal growth and cytoprotection after massive small intestinal resection. Future research should address the use of these agents in combination in short bowel syndrome.

Effect of sex and sex hormones on structural intestinal adaptation after massive small bowel resection in rats

PURPOSE

The gonadal steroids play a major role in the regulation of many functions. The purpose of the current study was to evaluate the effect of sex and sex hormones on intestinal adaptation in a rat model of short bowel syndrome (SBS).

METHODS

In the first experiment, male and female Sprague-Dawley rats underwent bowel transection and re-anastomosis (sham group) or 75% small bowel resection and anastomosis (SBS group). Relative changes in parameters of intestinal adaptation (overall bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth) were measured on day 15 and were compared with respect to sex. In the second experiment, male rats were divided into 4 experimental groups: SBS rats, SBS castrated rats, SBS castrated rats treated with testosterone, and SBS castrated rats treated with estradiol. Parameters of intestinal adaptation were compared with respect to hormonal treatment. Statistical significance was determined by Student's t test and analysis of variance with P < .05 considered significant.

RESULTS

Sex had minimal effects on intestinal adaptation. Both male and female rats showed a comparable increase in all parameters of intestinal adaptation. In the second experiment, castration led to significant decrease in bowel and mucosal weight, mucosal DNA and protein in both jejunum and ileum compared with SBS animals. Castrated rats also had lower jejunal villus height and crypt depth compared with SBS animals. Testosterone attenuated this negative effect of castration on bowel regrowth. Rats treated with testosterone showed a significant increase in bowel and mucosal weight, mucosal protein in both jejunum and ileum, mucosal DNA, villus height, and crypt depth in jejunum compared with castrated nontreated animals. Treatment with estradiol after resection and castration had minimal effect on bowel regrowth.

CONCLUSIONS

Bowel regrowth after massive small bowel resection is not sex-related. Depletion of androgens by castration inhibited intestinal adaptation. Testosterone has shown a strong stimulating effect on bowel regrowth.

The effect of growth hormone supplementation on late nutritional independence in pediatric patients with short bowel syndrome

PURPOSE

The use of growth hormone (GH) supplementation for intestinal adaptation among adult patients with short bowel syndrome (SBS) has provided mixed results. This report examines the effect of GH supplementation on SBS in pediatric patients.

METHODS

Two girls with SBS from neonatal gastrointestinal catastrophes received exogenous GH at 0.3 mg/kg per week subcutaneously and concurrent glutamine supplementation, beginning at 6 and 6(1/2) years of age. Changes in growth (height and weight) and changes in enteral and parenteral energy requirements were evaluated.

RESULTS

Treatment duration was 8 and 2.5 years, respectively. Patient weights increased from the 5th to the 41st percentile and from the 17th to the 23rd percentile, respectively. Height increased from the 1st to the 57th percentile in the former patient and increased from less than the 1st to the 17th percentile in the latter. Both patients are independent of parenteral nutrition and take enteral nutrition alone. Tolerance for enteral diets was significantly improved in each girl, with only 2 stools per day maintained in one patient.

CONCLUSIONS

The data show that late exogenous treatment with GH and glutamine supplementation improved growth parameters in pediatric patients with SBS. Growth hormone and glutamine supplementation may be beneficial in promoting late intestinal adaptation in pediatric patients with SBS. These data also suggest that these adjuncts may be useful in the early phases of intestinal adaptation.

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.

Weight loss and morphometric study of intestinal mucosa in rats after massive intestinal resection: influence of a glutamine-enriched diet

Short-bowel syndrome is responsible for significant metabolic alterations that compromise nutritional status. Glutamine is considered an essential nutrient for enterocytes, so beneficial effects from supplementation of the diet with glutamine are hypothesized.

PURPOSE

In this study, the effect of a diet enriched with glutamine was evaluated in rats undergoing extensive small bowel resection, with analysis of postoperative weight loss and intestinal morphometrics of villi height, crypt depth, and thickness of the duodenal and remnant jejunal mucosa.

METHODS

Three groups of male Wistar rats were established receiving the following diets: with glutamine, without glutamine, and the standard diet of laboratory ration. All animals underwent an extensive small bowel resection, including the ileocecal valve, leaving a remnant jejunum of only 25 cm from the pylorus that was anastomosed lateral-laterally to the ascendant colon. The animals were weighed at the beginning and end of the experiment (20th postoperative day). Then they were killed and the remnant intestine was removed. Fragments of duodenal and jejunal mucosa were collected from the remnant intestine and submitted to histopathologic exam. The morphometric study of the intestinal mucosa was accomplished using a digital system (KS 300) connected to an optic microscope. Morphometrics included villi height, crypt depth, and the total thickness of intestinal mucosa.

RESULTS

The weight loss comparison among the 3 groups showed no significant loss difference. The morphometric studies showed significantly taller duodenal villi in the glutamine group in comparison to the without glutamine group, but not different from the standard diet group. The measurements obtained comparing the 3 groups for villi height, crypt depth, and thickness of the remnant jejunum mucosa were greater in the glutamine-enriched diet group than for the without-glutamine diet group, though not significantly different from with standard-diet group.

CONCLUSIONS

In rats with experimentally produced short-bowel syndrome, glutamine-enrichment of an isonitrogenous test diet was associated with an improved adaptation response by the intestinal mucosa but not reduced weight loss. However, the adaptation response in the group receiving the glutamine-enriched diet was not improved over that for the group fed regular chow.

Growth factors in inflammatory bowel disease: the actions and interactions of growth hormone and insulin-like growth factor-I

Multiple growth hormones (GHs) and factors are relevant to inflammatory bowel disease (IBD) due to their trophic effects on epithelial cells to promote mucosal integrity, renewal, and repair, on mesenchymal cells to promote wound healing, and on intestinal immune cells to modulate inflammation. The anabolic effects of GHs and factors outside the intestine are relevant to minimizing nutritional insufficiency, catabolic state, and the inability to maintain body weight due to inflammation-induced malabsorption. GHs and factors can, however, have a dual role, whereby trophic effects can be beneficial but, if excessive, can promote complications including the increased risk of intestinal tumors/adenocarcinoma and fibrosis. This review focuses on GH and insulin-like growth factor (IGF-I), for which evidence suggests such a dual role may exist. The actions of GH and IGF-I on the healthy intestine are compared with effects during intestinal inflammation or associated complications. Interactions between these growth factors and others relevant to IBD are considered. The role of the newly discovered suppressors of cytokine signaling proteins, which may dictate the balance between beneficial and excessive actions of GH and IGF-I, is also addressed.

ATB0/ASCT2 expression in residual rabbit bowel is decreased after massive enterectomy and is restored by growth hormone treatment

Two weeks after 70% enterectomy, glutamine (Gln) transport is downregulated in rabbit residual bowel due to a decrease in system B(0) activity. Providing epidermal growth factor (EGF) and growth hormone (GH) restores Gln transport by increasing systems A and B(0,+) activities. We hypothesized that changes in Na(+)-dependent broad-spectrum neutral amino acid transporter (ATB(0)/ASCT2) protein and mRNA expression correlate with system B(0) activity. New Zealand White rabbits underwent 70% jejunoileal resection or no resection. Resected rabbits immediately received parenteral EGF, GH, both, or neither agent for 2 wk. Tissues harvested from jejunum, ileum, and colon were subjected to Western and Northern blot analyses for ATB(0)/ASCT2 protein and mRNA. In all tissues, ATB(0)/ASCT2 mRNA was reduced by approximately 50% in resected rabbits compared with nonresected controls. Similar reductions in protein amount occurred in the ileum and cecum. None of the growth factor treatments restored ATB(0)/ASCT2 protein, but GH treatment increased ATB(0)/ASCT2 mRNA abundance 250% in the residual ileum. Because changes in the ATB(0)/ASCT2 protein amount paralleled those in the system B(0) activity in this model, it is likely that this is the protein responsible for this transport system. The increase in mRNA abundance in rabbits treated with GH for 2 wk may be a harbinger of subsequent increases in transporter protein and activity. Unlike reported upregulation of transporters in human colon after small bowel resection, ATB(0)/ASCT2 protein and mRNA expression in rabbit colon are decreased, suggesting different regulatory pathways.

Smooth muscle overexpression of IGF-I induces a novel adaptive response to small bowel resection

Prior studies of intestinal adaptation after massive small bowel resection (SBR) have focused on growth factors and their effects on amplification of the gut mucosa. Because adaptive changes have also been described in intestinal smooth muscle, we sought to determine the effect of targeted smooth muscle growth factor overexpression on resection-induced intestinal adaptation. Male transgenic mice with smooth muscle cell overexpression of insulin-like growth factor I (IGF-I) by virtue of an alpha-smooth muscle actin promoter were obtained. SMP8 IGF-I transgenic (IGF-I TG) and nontransgenic (NT) littermates underwent 50% proximal SBR or sham operation and were then killed after 3 or 28 days. NT mice showed the expected alterations in mucosal adaptive parameters after SBR, such as increased wet weight and villus height. The IGF-I TG mice had inherently taller villi, which did not increase significantly after SBR. In addition, IGF-I TG mice had a 50% postresection persistent increase in remnant intestinal length, which was associated with an early decline and later increase in relative mucosal surface area. These results indicate that growth factor overexpression within the muscularis layer of the bowel wall induces significant postresection adaptive intestinal lengthening and a unique mucosal response. IGF-I signaling within the muscle wall may play an important role in the pathogenesis of resection-induced adaptation.

Intestinal rehabilitation and the short bowel syndrome: part 2

The management of patients with intestinal failure due to short bowel syndrome is complex, requiring a comprehensive approach that frequently necessitates long-term, if not life-long, use of parenteral nutrition. Despite tremendous advances in the provision of parenteral nutrition over the past three decades, which have allowed significant improvements in the survival and quality of life of these patients, this mode of nutritional support carries with it significant risks to the patient, is very costly, and ultimately, does not attempt to improve the function of the remaining bowel. Intestinal rehabilitation refers to the process of restoring enteral autonomy, and thus, allowing freedom from parenteral nutrition, usually by means of dietary, medical, and occasionally, surgical strategies. While recent investigations have focused on the use of trophic substances to increase the absorptive function of the remaining gut, whether intestinal rehabilitation occurs as a consequence of enhanced bowel adaptation or is simply a result of an optimized, comprehensive approach to the care of these patients remains unclear. In Part 1 of this review, we provided an overview of short bowel syndrome and pathophysiological considerations related to the remaining bowel anatomy in these patients. We also reviewed intestinal adaptation and factors that may enhance the adaptive process, focusing on evidence derived from animal studies. In Part 2, relevant data on the development of intestinal adaptation in humans are reviewed as is the general management of short bowel syndrome. Lastly, the potential benefits of a multidisciplinary intestinal rehabilitation program in the care of these patients are also discussed.

Net digestive absorption and adaptive hyperphagia in adult short bowel patients

BACKGROUND AND AIMS

Intestinal adaptation after small bowel resection in humans is debated. We have quantified in adult short bowel (remnant small bowel length <2 m) patients oral intake and net digestive absorption and their evolution over time.

PATIENTS AND METHODS

Oral intake and faecal output were studied over three days in 90 patients (39 and 51 without or with parenteral nutrition, respectively) and in 14 patients in early (<6 months) and late (>6 months) periods after digestive continuity. Nitrogen and fat output were measured using chemiluminescence and Van de Kamer techniques, respectively.

RESULTS

In the whole group, 81% of patients had hyperphagia (spontaneous oral intake >1.5 x resting energy expenditure), independently and negatively related to fat absorption (p<0.01) and body mass index (p<0.001) but not braked by the presence of parenteral nutrition. Protein and fat absorption were related to small bowel length. We observed, in the late in comparison with the early period after digestive continuity: an increase in oral intake (1.6 v 2.3 resting energy expenditure), decrease in stool weight/oral intake ratio, no reduction in per cent fat absorption, and protein absorption improvement associated with a significant increase in the amount of protein absorbed (40 v 64 g/day; p<0.05), both being correlated with remnant small bowel length (p<0.01).

CONCLUSIONS

This study confirms an adaptive hyperphagia in adult short bowel patients. Over time, hyperphagia and amount of protein absorbed increased, the latter being related to remnant small bowel length, indicating a behavioural adaptation that allows expression of intestinal absorptive adaptation.

Glutamine supplementation in infants with gastrointestinal disease: A randomized, placebo-controlled pilot trial

OBJECTIVE

Glutamine (Gln) is a non-essential amino acid that plays an important role in energy metabolism for gastrointestinal epithelia and other cells with rapid turnover. We evaluated the effects of enteral supplementation with Gln in infants undergoing surgery for congenital or acquired gastrointestinal disease.

METHODS

This was a randomized, double-masked, controlled clinical trial.

RESULTS

Twenty infants were randomly assigned to receive Gln (n = 9) or placebo amino acid (n = 11), with a goal of supplemental amino acid intake of 0.4 g.kg(-1).d(-1). Infants were weaned from parenteral nutrition, and enteral feeds were started according to a standardized feeding protocol. Median (interquartile range) durations of parenteral nutrition were 39 d (12 to 99) in the Gln group and 21 d (6 to 59) in the control group (P = 0.201). Median (interquartile range) durations needed to reach 80% of the US recommended dietary allowance for energy with enteral nutrition were 24 d (8 to 55) in the Gln group and 12.5 d (5 to 32) in the control group (P = 0.313). There were no differences in the occurrence of infections between groups. Among all infants enrolled, significant correlations were found between duration of parenteral nutrition and residual small bowel length, peak concentrations of direct bilirubin, and alanine aminotransferase. Peak direct bilirubin was associated with longer duration of parenteral nutrition, shorter gestation, older age before feeds were started, shorter bowel length, and larger amounts of parenteral energy and protein intake.

CONCLUSIONS

In this pilot trial, enteral Gln supplementation was well tolerated among infants with surgical gastrointestinal disease. There was no effect observed on the duration of parenteral nutrition, tolerance of enteral feeds, or intestinal absorptive or barrier function. Larger, multicenter trials in infants with surgical gastrointestinal disease are needed due to the variability in important outcome measurements.

Growth hormone, glutamine, and modified diet for intestinal adaptation

Many patients who undergo extensive resection of the gastrointestinal tract develop intestinal failure from short-bowel syndrome that results in significant malabsorption of fluid, electrolytes, and other nutrients. This may result in dependence on long-term parenteral nutrition. It has been almost a decade since Byrne and colleagues published their research demonstrating enhanced absorption of nutrients, improved weight gain, and reduction in parenteral nutrition requirements with the administration of a combination of growth hormone, glutamine, and a modified diet. Other researchers have conducted similar studies with inconsistent results. A systematic search on electronic databases and the Internet for the purpose of identifying the evidence published to date on this subject was performed. The analysis suggests administering recombinant human growth hormone alone or together with glutamine with or without a modified diet may be of benefit when the appropriate patients are selected for treatment.

Current update of short-bowel syndrome

PURPOSE OF REVIEW

The purpose of this article is to review the current data on trophic factors in adult patients with short-bowel syndrome. The present article reviews the clinical role of glutamine, growth hormone, and GLP-2 in the treatment of short-bowel syndrome.

RECENT FINDINGS

This review is clinically relevant, given the recent publications in this area. The summary of the current literature does not support that the currently available trophic factors are clinically beneficial for patients with short-bowel syndrome.

SUMMARY

Systemic side effects from growth hormone factors have been reported. Current trophic should be considered investigational and not standard of practice in the author's opinion.

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.

Histomorphometric bone modifications induced by growth hormone treatment in a rabbit model of short bowel syndrome

The effects of recombinant human growth hormone (rhGH) on cancellous and cortical bone were investigated in an experimental rabbit model of short bowel syndrome (SBS). Eighteen young male New Zealand rabbits, 2.0 +/- 0.2 kg b.w., were divided into three groups: an SBS Group submitted to a 70% midjejunoileal enterectomy and reanastomosis; an SBS-GH Group undergoing the same surgery and receiving 0.4 mg/kg/day rhGH for 28 days; a Control Group which was sham-operated. Thirty-five days after surgery, all the animals were pharmacologically euthanised and their femurs and L5 vertebrae were used for densitometric and histomorphometric studies. Vertebral and femoral densitometric results showed that the SBS Group presented significantly (P<0.01) lower values (10-25%) than the Control and SBS-GH Groups. Significant differences in the cancellous histomorphometric parameters, namely the trabecular bone area (-7% to 46%), trabecular thickness (-21% to 34%) and trabecular separation (17-32%), were observed between the SBS Group and the other groups. Both the SBS and SBS-GH Groups showed significantly (P<0.05) higher values than the Control Group in terms of cross-sectional area (approximately 24%), cortical area (approximately 20%), and periosteal perimeter (approximately 9%), while medullary area (41%) and endocortical perimeter (18%) were significantly higher (P<0.05) in SBS Group than those of Control Group. The current findings are encouraging and suggest that GH administration in SBS animal model used may improve skeletal tissue remodelling.

l-Alanyl-l-glutamine-supplemented parenteral nutrition improves infectious morbidity in secondary peritonitis

BACKGROUND & AIMS

A growing number of randomized clinical trials suggest that glutamine (Gln) supplementation may be beneficial in a selected group of patients and conditions. However, the effects of Gln-enriched total parenteral nutrition (TPN) on recovery from acute intra-abdominal infection have not been thoroughly investigated. Therefore, the aim of this study was to investigate whether the provision of Gln-enriched TPN after surgical and medical treatment of secondary peritonitis improves infectious morbidity.

METHODS

Thirty-three patients with secondary peritonitis were randomly assigned to receive either standard (n=16) TPN or L-alanyl-L-glutamine-supplemented (n=17) TPN, after medical and surgical treatment of the infectious focus. The two TPN formulae were isonitrogenous and isocaloric, which commenced the morning after surgery and ran continuously for 10 consecutive days. The control group received standard TPN, while the treatment group was given L-alanyl-L-glutamine, 0.40 g/kg/d (Dipeptiven, Fresenius Kabi, Bad Homburg, Germany). Infectious morbidity, nitrogen balance, leukocytes, lymphocytes, subpopulations CD(4) and CD(8), Immunoglobulin A (IgA), total proteins, albumin, hospital and intensive care unit (ICU) stays, and mortality were evaluated. Statistical analysis included one-way ANOVA, the unpaired Student's t-test, the Mann-Whitney U-test, chi(2) test, or Fisher's exact test.

RESULTS

Patients in both groups were comparable prior to the operation. Nitrogen balance and the levels of albumin and IgA were significantly better than those in the control group. Also, a significant reduction in the infectious morbidity was found in the Gln-treated group. Lymphocyte counts as well as subpopulations CD(4) and CD(8), and proteins showed a propensity to improvement and a tendency to reduced rates of mortality were observed when comparing the groups. Hospital and ICU stays were similar.

CONCLUSION

L-alanyl-L-glutamine-supplemented TPN improved the infectious morbidity of patients with secondary peritonitis. Gln supplementation to parenteral nutrition may be an alternative for enhancing host defenses and improving infectious morbidity.

New and emerging therapies for short bowel syndrome in children

This review provides an overview of traditional as well as emerging therapies useful in the management of pediatric short bowel syndrome. Pediatric short bowel syndrome is relatively uncommon; however, when it does occur, it presents a unique challenge to medical care providers. The use of parenteral and enteral nutrition to maximize growth and enhance intestinal adaptation so as to increase absorptive surface area has been the primary focus of therapy. In recent years, the advent of pharmacologic advances, including the use of antibacterial drugs, anti-motility drugs and hormonal therapies, has had a significant impact on this condition. At times, surgery may be indicated for dealing with complications, or providing alternative therapy such as transplantation. With ongoing research, it is likely that improved pharmacologic therapy will be available for enhanced intestinal adaptation, control of gut motility, treatment of small bowel bacterial overgrowth, and treatment of rejection following small intestinal transplantation.

Living-related bowel transplantation to treat short bowel syndrome in a four-year-old child: a case report

PURPOSE

Short bowel syndrome (SBS) is an extremely challenging clinical problem in children. Although many patients can be maintained for a period of time on total parenteral nutrition (TPN), many of these children suffer from the morbidity and mortality associated with sequential central line infections, venous thromboses, and TPN-induced liver failure. Intestinal transplantation often is the only chance for long-term survival. Unfortunately, many children die every year waiting for size-matched cadaveric intestine to become available.

METHODS

After our success with living-related bowel transplantation in adults, the authors successfully transplanted 150 cm of maternal ileum into a 4-year-old 10-kg child with profound malnutrition from SBS and advanced TPN-induced liver failure. Because of the size mismatch, the abdominal cavity could not be closed primarily. The defect was covered with absorbable mesh and subsequently with skin graft.

RESULTS

The patient is home with excellent bowel and liver function, off hyperalimentation, and on a regular diet. No rejection has been encountered.

CONCLUSIONS

Living-related intestinal transplantation is a life-saving alternative to cadaveric intestinal transplantation in children with short bowel syndrome.

Influência da glutamina na mucosa do instestino de ratos submetidos à enterectomia extensa

OBJETIVO: Avaliar a influência de uma dieta suplementada com glutamina sobre as alterações adaptativas no intestino delgado de ratos com enterectomia extensa. MÉTODO: Vinte ratos Wistar, divididos aleatoriamente em dois grupos de dez animais, foram enterectomizados e alimentados com dois tipos diferentes de dieta nos 14 dias de pós-operatório: grupo controle (GC)-dieta padrão; grupo glutamina (GG)-dietapadrão acrescida de 3,05% de glutamina. Avaliou-se evolução ponderal, peso da mucosa intestinal (PM), profundidade das criptas (PC), altura das vilosidades (AV), espessura da parede (EP) e o conteúdo de ácido desoxirribonucléico (DNA) na mucosa intestinal, no início e no final do experimento. RESULTADOS: Com exceção da PC ileal do Grupo GG, todas as variáveis estudadas tiveram um aumento significativo em seus valores finais tanto no jejuno quanto no íleo (p<0,05).Entre os grupos, a comparação do PM, AV, DNA da mucosa, no jejuno e no íleo, tanto inicialmente quanto no final do estudo, bem como da EP inicial no jejuno e íleo eda PC no jejuno final e no íleo inicial e final não mostraram diferenças significativas (p>0,05). No jejuno inicial, a PC no grupo GC foi maior (p=0,005). A EP do jejuno e íleo final foi maior no grupo GC. CONCLUSÃO: A suplementação dietética com a glutamina não melhorou as alterações adaptativas que ocorrem no remanescente intestinal.

Adaptation following intestinal resection: mechanisms and signals

The intestine has an inherent ability to adapt morphologically and functionally in response to internal and external environmental changes. The functional adaptations encompass modifications of the brush border membrane fluidity and permeability, as well as up- or down-regulation of carrier-mediated transport. Intestinal adaptation improves the nutritional status following the loss of a major portion of the small intestine, following chronic ingestion of ethanol, following sublethal doses of abdominal irradiation, in diabetes, in pregnancy and lactation, with ageing, and with fasting and malnutrition. Following intestinal resection, morphological and functional changes occur depending upon the extent of the intestine removed, the site studied, and the lipid content of the diet. Therefore, intestinal adaptation has important implications in the survival potential and welfare of the host. An understanding of the mechanisms of, and signals for, intestinal adaptation in the experimental setting forms the basis for the use of management strategies in humans with the short-bowel syndrome.

Indications for specific therapy in the rehabilitation of patients with the short-bowel syndrome

Diarrhoea, malabsorption and malnutrition characterize the short-bowel syndrome. Following the initial intestinal resection, complications such as fistulas and intra-abdominal abscesses may occur, but these usually resolve with appropriate surgical care. All residual intestine should be placed in continuity before serious attempts at rehabilitation with oral feedings are initiated. Small hourly oral feedings composed of food items high in complex carbohydrate and low in fat are started when appropriate and the diet is gradually increased as intestinal adaptation occurs. The goal during this process is to prevent diarrhoea and allow the formation of semiformed stools. With time, parenteral nutrition (PN) can be reduced, and the time required depends on both length of residual bowel and the particular anatomy involved-for example, the presence or absence of the colon. A programme of optimal diet plus growth hormone (0.1 mg/kg) and oral glutamine (30 g/day) enhances the adaptive process and allows many patients independence from PN. However, those with extremely short segments of jejuno-ileum (<50 cm) and no colon have excessive fluid and electrolyte losses, and intestinal transplantation may be the only therapy which allows such patients to be independent of PN.

Experimental approaches: dietary and hormone therapy

Patients who suffer from intestinal failure depend on parenteral support to maintain nutritional equilibrium. In this chapter, recommendations for evaluation the absorptive capacity of patients with intestinal failure are defined, and the evidence and magnitude of the effect of dietary and hormone therapy is given. Regarding dietary advice, the effects of employment of diets with various carbohydrate:fat ratios in short-bowel syndrome (SBS) patients with and without a preserved colon is presented. Focus has been placed on the use of growth hormone but also on the use of a novel intestinotrophic hormone, glucagon-like peptide 2, in the promotion of intestinal adaptation in SBS patients. Overall, the ultimate aim in the treatment of SBS patients is to optimize remnant intestinal function, thereby eliminating the need for parenteral support and improving quality of life in these patients.

Effects of bowel rehabilitation and combined trophic therapy on intestinal adaptation in short bowel patients

AIM: To evaluate the effects of bowel rehabilitation and combined trophic therapy on intestinal adaptation in short bowel patients.

METHODS: Thirty-eight patients with severe short-bowel syndrome (SBS) were employed in the present study, whose average length of jejunum-ileum was 35.8 ± 21.2 cm. The TPN treatment was initiated early to attain positive nitrogen balance and prevent severe weight loss. The TPN composition was designated to be individualized and altered when necessary. Enteral feeding was given as soon as possible after resection and increased gradually. Meals were distributed throughout the day. Eight patients received treatment of growth hormone (0.14 mg/kg•d) and glutamine (0.3 g/kg•d) for 3 wk. D-xylose test, ¹⁵N-Gly trace test and ¹³C-palmitic acid breath test were done to determine the patients' absorption capability.

RESULTS: Thirty-three patients maintained well body weight and serum albumin concentration. The average time of follow-up for 33 survival patients was 5.9 ± 4.3 years. Twenty-two patients weaned from TPN with an average TPN time of 9.5 ± 6.6 mo. Two patients, whose whole small bowel, ascending and transverse colon were resected received home TPN. An other 9 patients received parenteral or enteral nutritional support partly as well as oral diet. Three week rhGH + GLN therapy increased nutrients absorption but the effects were transient.

CONCLUSION: By rehabilitation therapy, most short bowel patients could wean from parenteral nutrition. Dietary manipulation is an integral part of the treatment of SBS. Treatment with growth hormone and glutamine may increase nutrients absorption but the effects are not sustained beyond the treatment period.

Trophic and cytoprotective nutrition for intestinal adaptation, mucosal repair, and barrier function

Intestinal epithelial cell turnover (proliferation, migration, differentiation, and apoptosis) and gut barrier functions are dynamic processes that are markedly affected by nutritional status, the route of feeding, and the adequacy of specific nutrients in the diet. Emerging studies are defining potential therapeutic roles for specific nutrients and diet-derived compounds (including arginine, glutamate, glutamine, glutathione, glycine, vitamin A, zinc, and specific lipids) in gut mucosal turnover, repair, adaptation after massive bowel resection, and barrier function. The role and regulation of endogenous bowel flora in generating short-chain fatty acids from diet-derived fiber and other diet-derived compounds and the effects of these agents on gut function are increasingly being elucidated. Results of these investigations should define new nutritional methods for trophic and cytoprotective effects on the intestine in conditions such as inflammatory bowel disease, malnutrition, and short bowel syndrome.

Growth hormone and epidermal growth factor together enhance amino acid transport systems B0,+ and A in remnant small intestine after massive enterectomy

BACKGROUND

Sodium-dependent brush-border nutrient transport is decreased 2 weeks after massive enterectomy. This down-regulation is ameliorated by a 1-week infusion of parenteral growth hormone (GH) and epidermal growth factor (EGF) started 1 week after resection. We hypothesize that glutamine (GLN) transport will be enhanced by earlier and longer growth factor infusion, with differential effects on the Na(+)-dependent GLN transport systems A, B(0,+), and B(0)/ASCT2.

MATERIALS AND METHODS

New Zealand White rabbits underwent 70% small bowel resection then immediately received parenteral EGF, GH, both EGF and GH, or neither for 2 weeks. Na(+)-dependent 3H-GLN uptake by jejunal and ileal brush-border membrane vesicles was measured and the contribution of systems A, B(0,+), and B(0) was then determined by competitive inhibition. Data were analyzed using one-way analysis of variance.

RESULTS

In nonresected animals, the relative contribution of the systems was similar in jejunum (A 9%, B(0,+) 20%, and B(0) 71%) and ileum (A 13%, B(0,+) 27%, and B(0) 60%). Na(+)-dependent GLN uptake was reduced by one half in resected untreated controls, primarily because of decreased B(0) activity. EGF or GH alone did not affect Na(+)-dependent GLN transport, but, as a combination, there was increased uptake in the residual ileum and jejunum by 144% and 150%, respectively, over resected controls (P < 0.05). This was twice that achieved by delayed and shorter-duration combination treatment. This augmentation was a result of a 6.1-8.2-fold increase in system A as well as a 3.8-3.9-fold enhancement of system B(0,+) activity in remnant ileum and jejunum (P < 0.01).

CONCLUSIONS

Parenteral EGF and GH, given in combination for 2 weeks immediately after massive enterectomy, synergistically enhance GLN uptake by systems A and B(0,+).

Role of specific amino acids in nutritional support

Attempts have been made over the past decade to evaluate the role of specific amino acids in the nutritional support of surgical patients. Particular attention has been paid to the branched-chain amino acids, glutamine, and a collection of compounds that have been referred to as 'immunonutrients'. The present review provides an overview of the rationale behind the use of these nutrients and reviews information about their role in patients undergoing surgery. In general, although the use of immunonutrients enhances the nutritional status of patients, and although a number of clinical trials have claimed clinical advantages, there are still doubts about their clinical utility and concerns about their high cost.

Clinical evidence for enteral nutritional support with glutamine: a systematic review

OBJECTIVE

The purpose of this systematic review was to locate and assess the quality of scientific evidence to establish a graded recommendation based on the effectiveness of glutamine-enriched enteral nutrition in different medical and surgical conditions. We were concerned with the following topics: 1) benefits of enteral administration of glutamine in different pathologic conditions, and 2) dose, duration, and time of initiation of glutamine-enriched diets.

METHODS

The sources consulted for the search were MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Healthstar and HSTAT. Ninety-one studies were assessed; after a methodologic review (primary review), only 16 studies met the inclusion criteria for analysis by a group of experts (secondary review). The coordinators supervised all data, and a final consensus was reached among the coordinators, experts, and methodologists.

RESULTS AND CONCLUSIONS

Glutamine-enriched diets showed good overall tolerance, improvement of immunologic aspects in multiple trauma patients, cost reduction in critically ill patients, and improvement of mucositis in post-chemotherapy patients (grade B recommendations). The doses given and the duration of therapy varied widely depending on the pathologic condition. Intake of 20 to 30 g/d, early initiation of diet, and maintenance for 5 d or longer are recommended (grade C recommendations).

Intestinal transplantation

Advances in immunosuppressive treatment as well as better monitoring and control of acute rejection have brought intestinal transplantation (ITx) into the realm of standard treatment for permanent intestinal failure. The results from the intestinal Transplant International Registry (www.intestinaltransplant.org) indicate that ITx is currently an acceptable clinical modality for selected patients with permanent intestinal failure. The goal of this short review is to deal with indications, clinical results and complications of ITx. Although it has been used in humans for the past two decades, very few data are available regarding graft function and its monitoring.

Enteral glutamine stimulates protein synthesis and decreases ubiquitin mRNA level in human gut mucosa

Effects of glutamine on whole body and intestinal protein synthesis and on intestinal proteolysis were assessed in humans. Two groups of healthy volunteers received in a random order enteral glutamine (0.8 mmol.kg body wt(-1)x h(-1)) compared either to saline or isonitrogenous amino acids. Intravenous [2H5]phenylalanine and [13C]leucine were simultaneously infused. After gas chromatography-mass spectrometry analysis, whole body protein turnover was estimated from traced plasma amino acid fluxes and the fractional synthesis rate (FSR) of gut mucosal protein was calculated from protein and intracellular phenylalanine and leucine enrichments in duodenal biopsies. mRNA levels for ubiquitin, cathepsin D, and m-calpain were analyzed in biopsies by RT-PCR. Glutamine significantly increased mucosal protein FSR compared with saline. Glutamine and amino acids had similar effects on FSR. The mRNA level for ubiquitin was significantly decreased after glutamine infusion compared with saline and amino acids, whereas cathepsin D and m-calpain mRNA levels were not affected. Enteral glutamine stimulates mucosal protein synthesis and may attenuate ubiquitin-dependent proteolysis and thus improve protein balance in human gut.

Growth hormone and epidermal growth factor together enhance amino acid transport systems B(0,+) and A in remnant small intestine after massive enterectomy

BACKGROUND

Sodium-dependent brush border nutrient transport is decreased 2 weeks after massive enterectomy. This downregulation is ameliorated by a 1-week infusion of parenteral growth hormone (GH) and epidermal growth factor (EGF) started 1 week after resection. We hypothesized that glutamine (GLN) transport would be enhanced by earlier and longer growth factor infusion, with differential effects on the Na(+)-dependent GLN transport systems A, B(0,+), and B0/ASCT2.

MATERIALS AND METHODS

New Zealand White rabbits underwent 70% small bowel resection then immediately received parenteral EGF, GH, both, or neither for 2 weeks. Na(+)-dependent 3H-GLN uptake by jejunal and ileal brush-border membrane vesicles was measured and the contribution of systems A, B(0,+), and B0 then determined by competitive inhibition. Data were analyzed using one-way analysis of variance.

RESULTS

In nonresected animals, the relative contribution of the systems was similar in jejunum (A, 9%, B(0,+), 20%; and B0, 71%) and ileum (A, 13%; B(0,+), 27%; and B0, 60%). Na(+)-dependent GLN uptake was reduced by half in resected, untreated controls, primarily because of decreased B(0) activity. EGF or GH alone did not affect Na(+)-dependent GLN transport, but as a combination, increased uptake in the residual ileum and jejunum by 144% and 150%, respectively, over resected controls (P<0.05). This was twice that achieved by delayed and shorter-duration combination treatment. This augmentation was due to a 6.1- to 8.2-fold increase in system A as well as a 3.8- to 3.9-fold enhancement of system B(0,+) activity in remnant ileum and jejunum (P<0.01).

CONCLUSIONS

Parenteral EGF and GH, given in combination for 2 weeks immediately after massive enterectomy, synergistically enhance GLN uptake by systems A and B(0,+).

Immune-enhancing enteral diet increases blood flow and proinflammatory cytokines in the rat ileum

BACKGROUND

Enteral feeding improves outcome following surgery. Benefits depend on timing, route (enteral vs parenteral), and nutrient composition (standard vs immune-enhancing diets; IED). IED augments intestinal immunity and stimulates gut blood flow during absorption in a nutrient-specific manner. We hypothesize that a mechanism for the gut protective effect of IED is augmentation of blood flow to the gut-associated lymphoid tissue (GALT) in the terminal ileum.

METHODS

Male Sprague-Dawley rats (200-230 g) were fed for 5 days either an IED (Impact, Novartis) or an isocaloric, isonitrogenous control diet (CD, Boost, Mead-Johnson) matched to the daily caloric intake (rat chow). Rats were then anesthetized and cannulated for microsphere determination of whole organ blood flow. Blood glucose levels and blood flow to abdominal organs were determined at baseline and 30, 60, 90, and 120 min after gastric gavage (2 ml) with IED or CD. Intestinal tissues were harvested for cytokine levels (ELISA: IL-4, IL-10, IFN-gamma, and IgA).

RESULTS

Chronic IED increased baseline blood flow in the distal third of the small intestine compared to chow-fed and CD. Baseline blood flow was comparable between IED and CD in all other organs. CD and IED produced different blood flow patterns after gavage. CD increased blood flow compared to baseline and IED in antrum, duodenum, and jejunum. Ileal blood flow remained elevated in IED rats for 2 h, perhaps suggesting maximal blood flow. IED increased blood glucose compared to CD. Chronic IED increased IL-4 and decreased IL-10 in the terminal ileum.

CONCLUSIONS

Chronic IED exposure increases and sustains ileal blood flow compared to CD with altered proinflammatory cytokine expression. Our data suggest that a mechanism for the IED effect involves the selective perfusion of the terminal ileum and contiguous GALT during IED nutrient absorption.

IGF-I treatment facilitates transition from parenteral to enteral nutrition in rats with short bowel syndrome

The goal of growth factor treatment in patients with short bowel syndrome (SBS) is to facilitate transition from parenteral to enteral feedings. Ideal use of growth factors would be acute treatment that produces sustained effects. We investigated the ability of acute insulin-like growth factor I (IGF-I) treatment to facilitate weaning from total parenteral nutrition (TPN) to enteral feeding in a rat model of SBS. After a 60% jejunoileal resection + cecectomy, rats treated with IGF-I or vehicle were maintained exclusively with TPN for 4 days and transitioned to oral feeding. TPN and IGF-I were stopped 7 days after resection, and rats were maintained with oral feeding for 10 more days. In IGF-I-treated rats, serum concentration of IGF-I and final body weight were significantly greater because of a proportionate increase in carcass lean body mass than in vehicle-treated rats. Acute IGF-I treatment induced sustained jejunal hyperplasia on the basis of significantly greater concentrations of jejunal mucosal protein and DNA without a change in histology or sucrase activity. These results demonstrate that acute IGF-I facilitates weaning from parenteral to enteral nutrition in association with maintenance of a greater body weight and serum IGF-I concentration in rats with SBS.

Omega-3 fatty acids in immune-enhancing enteral diets selectively increase blood flow to the ileum by a bile acid dependent mechanism

BACKGROUND

The immune-enhancing diet (IED) (Impact, Novartis Corp, Minneapolis, Minn) initiates a delayed and sustained increase in blood flow to the ileum and gut-associated lymphoid tissue. The immune-enhancing benefits of Impact (Novartis Corp) are attributed to the addition of L-arginine, fish oil (FO), and RNA fragments to a standard enteral diet. The sustained increase in blood flow to the gut-associated lymphoid tissue during IED exposure might account for these immune effects. We hypothesized that the increase in ileal blood flow with IED might be a result of ileal omega-3 fatty acid absorption in the ileum by a bile-dependent mechanism.

METHODS

Male Sprague-Dawley rats (200 g-230 g) were anesthetized and cannulated for microsphere measurement of whole organ blood flow. Rats received gastric gavage (2 mL) with either IED, an isocaloric, isonitrogenous control diet (CD) (Boost, Mead-Johnson, Evansville, Ind), CD plus menhaden FO (CD+FO), or CD+FO plus bile duct ligation (BDL). Blood flow was determined at baseline and 30, 60, and 120 minutes after short-term gavage.

RESULTS

Baseline blood flow and central hemodynamics were comparable in all groups. In the ileum, at 120 minutes postgavage, blood flow was increased by IED and CD+FO compared with baseline and CD. BDL prevented the increase in blood flow in the CD+FO+BDL rats. All groups exhibited differences in splanchnic blood flow distribution after gavage: CD and CD+FO+BDL increased blood flow compared with baseline early in the proximal gut and spleen. IED and CD+FO produced a delayed, sustained hyperemia to the distal gut.

CONCLUSIONS

Gastrointestinal blood flow distribution after feeding is dependent on nutrient composition. These findings suggest that omega-3 fatty acids are the components of the enteral IED, Impact (Novartis Corp), which produce the increased blood flow to the terminal ileum and its contiguous gut-associated lymphoid tissue. Our data suggests that an intact enterohepatic bile pathway is needed for the IED blood flow effect.

Nutritional support in cancer patients

This article will summarize the current nutrition strategies in cancer patients. A review of relevant studies dealing with nutrition in cancer patients is presented. Basic recommendations for feeding patients with malignancy are suggested. Early nutrition evaluation, assessment, and support should be instituted in the appropriate clinical setting. Use of specialized nutrition support is not indicated in well-nourished cancer patients undergoing surgery, chemotherapy, or radiotherapy in whom adequate oral intake is anticipated. Severely malnourished patients need early nutrition support preoperatively. Postoperative nutrition support has to be initiated in a timely fashion depending on the disease process. An algorithm for decisions regarding administration of specialized nutrition support is proposed.

The anabolic effects of recombinant human growth hormone and glutamine on parenterally fed, short bowel rats

AIM: To evaluate the metabolic effects associated with administration of rhGH and/or Gln in parenterally fed, short-bowel rats.

METHODS: Forty SD rats subjected to 75% intestinal resection and maintained with parenteral nutrition were randomly divided into 4 groups as follows: -rhGH, -Gln; -rhGH, +Gln; +rhGH, -Gln; +rhGH, +Gln. Body weight and nitrogen balance were evaluated daily. After 6 d of PN, rats were killed, various organs were dissected and weighted, the carcasses were used for analysis of body composition. Serum GH and IGF-1 were determined by RIA method.

RESULTS: Weight loss in rats with rhGH (17.4 ± 12.8 g) and rhGH+Gln (23.8 ± 3.5 g) was significantly less than rats with PN alone (29.6 ± 6.9 g) and rats with Gln-supplemented PN (31.85 ± 12.8 g), P < 0.05. The accumulated NB in rats with rhGH (1252.9 ± 294.3 mg N/d) and rhGH+Gln (1261.7 ± 85.5 mg N/d) was significantly greater than those with PN alone (704.8 ± 379.0 mg N/d) and with Gln-supplemented PN (856.7 ± 284.4 mg N/d), P < 0.05. The absolute weight of gastrocnemius muscle in rats with rhGH (2683.9 ± 341.6 mg) and rhGH+Gln (2579.1 ± 359.5 mg) was greater than those with PN alone (2176.3 ± 167.1 mg) and with Gln-supplemented PN (2141.9 ± 353.6 mg). Although the absolute weight of remnant small intestine itself was not significantly different in 4 experimental groups, the weight/length of the segments was greater in rats with rhGH and/or Gln (48.7 ± 5.5, 52.7 ± 4.1 and 67.4 ± 5.3 respectively) than those with PN alone (47.8 ± 5.0), there were synergistic effects between rhGH and Gln in improvement of the weight/length of remnant small intestine, P < 0.05. Analyses of body carcass composition showed that a higher percentage of carcass weight as protein and a lower percentage of carcass weight as fat were occurred in rats with rhGH (20.8 ± 4.0, 6.0 ± 2.6) and rhGH+Gln (21.3 ± 2.4, 4.4 ± 1.5) than those with PN alone (16.4 ± 2.4, 9.2 ± 3.7) and with Gln-supplemented PN (17.8 ± 3.0, 6.3 ± 2.0), rhGH had significant effects on alteration of body composition, P < 0.05. Serum GH and IGF-1 concentration in rats with rhGH (5.221 ± 0.8 and 425.1 ± 19.2 ng/mL respectively) and rhGH+Gln (5.507 ± 1.0 and 461.1 ± 49.9 ng/mL respectively) were greater than those with PN alone (3.327 ± 1.7 and 325.8 ± 29.6 ng/mL respectively) and with Gln-supplemented PN (3.433 ± 0.1 and 347.7 ± 55.7 ng/mL respectively), P < 0.01.

CONCLUSION: rhGH significantly improves the anabolism in parenterally fed. Short bowel rats, anabolic effect with Gln is less dramatic, there is no synergistic effect between rhGH and Gln in improvement of whole body anabolism. IGF-1 plays an important part in growth-promoting effects of rhGH.

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.

Immune-enhancing enteral diet selectively augments ileal blood flow in the rat

BACKGROUND

Clinical studies show that immune-enhancing enteral diets (IED; with L-arginine, fish oil, and RNA fragments) decrease the rate of sepsis and shorten the length of hospital stay after the start of enteral feeding. These beneficial effects are dependent on the route of administration (enteral vs parenteral) and on the nutrient composition (IED vs standard diets). Gut exposure to an IED seems to preserve and/or augment intestinal mucosal immunity. However, nutrient absorption stimulates gut blood flow in a nutrient-specific manner (i.e., postprandial hyperemia). We hypothesized that an IED would initiate a different pattern of whole organ blood flow compared to a standard diet. This suggests that a mechanism for the protective effect of IED might be the preferential augmentation of gut blood flow to gut-associated lymphoid tissue (GALT) or mucosa-associated lymphoid tissue (MALT).

METHODS

Male Sprague-Dawley rats (200-225 g) were anesthetized and cannulated for colorimetric microsphere determination of blood flow distribution (with the phantom organ technique). Animals received gastric gavage (2 ml) of an IED (Impact; Novartis) or an isocaloric, isonitrogenous control diet (Boost; Mead-Johnson). Blood flow to the antrum, duodenum, jejunum, ileum, colon, liver, kidneys, and spleen was determined at baseline and 30, 60, 90, and 120 min after gavage.

RESULTS

Baseline blood flows to the left and right kidneys were within 10%, indicating the technical integrity of the microsphere technique and assay. Control diet augmented blood flow compared to IED in the antrum, duodenum, jejunum, and spleen. Conversely, IED gavage stimulated a delayed and sustained hyperemic response in the ileum. IED also increased hepatic blood flow early (30 min). IED increased blood glucose levels compared to control diet at 30, 60, and 90 min, suggesting enhanced nutrient absorption.

CONCLUSIONS

These data show that blood flow distribution depends on nutrient composition and that IED preferentially augments blood flow to the ileum. Since the terminal jejunum and ileum contain much of the GALT, our data suggest that a mechanism for enterally stimulated mucosal immunity involves selective perfusion of the terminal ileum during IED nutrient absorption.

An integrated approach to intestinal failure: results of a new program with total parenteral nutrition, bowel rehabilitation, and transplantation

Intestinal failure can be treated with bowel rehabilitation, total parenteral nutrition, or intestinal transplantation. Little has been done to integrate these therapies for patients with intestinal insufficiency or failure and to develop an algorithm for appropriate use and timing. We established a multidisciplinary program using bowel rehabilitation, total parenteral nutrition, or intestinal transplantation as appropriate in a large population. Evaluation included clinical, pathologic, and psychosocial assessments and assignment to therapy based on the results of this evaluation. Of 59 patients evaluated for life-threatening complications of intestinal failure, 68% were considered appropriate candidates for transplantation, 10% were managed with rehabilitation, and 17% were maintained on optimized long-term parenteral nutrition. Nineteen transplants were performed, with 78% patient survival and 66% graft survival. Patient survival among isolated intestine recipients was 90%. All patients managed with rehabilitation were weaned from parenteral nutrition within 6 months. Long-term management with parenteral nutrition resulted in a significant number of deaths both among patients waiting for a transplant and those who were poor candidates for transplant. Intestinal rehabilitation, when successful, is optimal. For patients with irreversible intestinal failure, isolated intestinal transplantation holds particular promise. Parenteral nutrition is plagued by high failure rates among this population of debilitated patients compared with the general parenteral nutrition population. Integration of these therapies, with individualization of care based on a multidisciplinary approach and perhaps with earlier isolated intestinal transplantation for patients with irreversible intestinal failure, should optimize survival.

Protective nutrients and functional foods for the gastrointestinal tract

Epithelial and other cells of the gastrointestinal mucosa rely on both luminal and bloodstream sources for their nutrition. The term functional food is used to describe nutrients that have an effect on physiologic processes that is separate from their established nutritional function, and some of these nutrients are proposed to promote gastrointestinal mucosal integrity. We review the recent in vitro, animal, and clinical experiments that evaluated the role of several types of gastrointestinal functional foods, including the amino acids glutamine and arginine, the essential micronutrients vitamin A and zinc, and 2 classes of food additives, prebiotics and probiotics. Many of the data from preclinical studies support a strong role for enteral nutrients in gastrointestinal health; in comparison, the data from human studies are limited. In some cases, impressive data from in vitro and animal studies have not been replicated in human trials. Other clinical trials have shown positive health benefits, but some of those studies were plagued by flaws in study design or analysis. The methods available to detect important changes in human gastrointestinal function and structure are still limited, but with the development of more sensitive measures of gastrointestinal function, the effects of specific nutrients may be more easily detected. This may facilitate the development of phase 3 clinical trials designed to more rigorously evaluate the effects of a particular nutrient by focusing on valid and reliable outcome measures. Regulatory changes in the way in which health claims can be made for dietary supplements should also be encouraged.

Intestinal adaptation in short bowel syndrome

Regaining enteral autonomy after extensive small bowel resection is dependent on intestinal adaptation. This adaptational process is characterized by hyperplastic growth of the remaining gut, which is accompanied by both an increase of cell division at the level of the crypt cells and by an increased rate of programmed cell death (apoptosis). Apart from the absorptive function, the small bowel also has a barrier function and plays an important role in interorgan metabolism. Also, these functions are greatly affected by a massive intestinal resection and subsequent recovery by intestinal adaptation. This review aims to give an overview of the debilitating effects of massive intestinal resection on gut function and subsequently discusses intestinal adaptation and possible factors stimulating adaptation.