Parenteral nutrition is associated with intestinal morphologic and functional changes in humans

Impact of caloric intake on parenteral nutrition-associated intestinal morphology and mucosal barrier function

BACKGROUND

Parenteral nutrition (PN) is known to induce villus atrophy, epithelial cell (EC) apoptosis, and increase mucosal permeability. The study hypothesized that increasing amounts of energy delivery to mice would result in the best outcome, with the least effects on the mucosa.

METHODS

Mice were randomized to enteral controls (saline infusion with ad libitum enteral food) or to 1 of 3 PN groups (with no enteral nutrition): full (100% of daily average energy intake for the mouse), reduced (75% of energy intake) or very low (50% of energy intake). Mice received PN for 7 days. Mucosal morphology, EC apoptosis, and bacterial translocation were assessed.

RESULTS

Villus height decreased significantly with decreasing levels of caloric intake and was significantly lower in all PN groups compared with controls. Body weight loss was significantly greater in PN groups vs controls and was greatest in mice with the lowest caloric delivery. A consistent trend toward a higher EC apoptotic index with decreasing caloric intake was observed, and apoptosis in all PN groups exceeded controls (2-fold). All PN groups demonstrated greater bacterial translocation than controls.

CONCLUSIONS

PN induces intestinal EC apoptosis and villus and crypt atrophy, even at 100% of predicted energy needs, and such changes increased with greater reduction of energy intake. This study supports a concept that lack of enteral nutrition, rather than absolute caloric levels, is responsible for many of the adverse effects of PN. The study also allows the investigators to better optimize a mouse model of PN delivery.

Specific topics and complications of parenteral nutrition

BACKGROUND/AIMS

Total parenteral nutrition (TPN) has proven a tremendous advance in all disciplines in medicine but itself introduces a spectrum of possible complications related to both the parenteral nutritional solution as well as the technique of intravenous delivery. Our aim is to review the specific complications of TPN.

MATERIALS AND METHODS

This article presents a critical literature review of relevant topics in TPN-related complications-metabolic, infections, and nutrition related.

RESULTS

Special emphasis focuses on complications of TPN arising from thrombosis or infectious sequelae related to the central venous catheterization and metabolic complications involving the kidneys, bones, liver, and biliary tract.

CONCLUSIONS

Awareness and surveillance of TPN-related complications can prevent, potentially, some of these complications related to parenteral nutritional support.

Management of gallstone pancreatitis

Gallstones are the most common cause of acute pancreatitis in the western world. Most patients with ABP suffer a mild attack and are expected to make a full recovery. They can be managed supportively and undergo laparoscopic cholecystectomy with IOC during their initial hospitalization to prevent recurrence. If necessary, laparoscopic common bile duct exploration can be performed. Otherwise, postoperative ERCP can be performed to remove common bile duct stones. Patients with severe ABP require ICU admission, close clinical monitoring, and aggressive fluid resuscitation. There is a bimodal mortality in severe ABP with most late deaths caused by septic complications. Antibiotics should be used judiciously and are usually warranted only in the presence of infection or sepsis. ERCP, +/- ES, should be performed when signs of cholangitis are present. Early ERCP should be considered in patients with severe ABP who do not improve clinically. CT scanning should be performed to assess for necrosis or peripancreatic fluid collections. Patients with no fluid collections can undergo cholecystectomy once their clinical condition improves. Patients with peripancreatic fluid collections should be followed with serial CT scans. Laparoscopic cholecystectomy should be performed once resolution of the fluid collection is documented. If fluid collections do not resolve after 6 weeks, patients should undergo concurrent cholecystectomy and fluid drainage procedures. Sterile necrosis can be closely monitored and does not require necrosectomy unless the patient's clinical status deteriorates. Patients with infected necrosis should undergo necrosectomy when they are clinically stable. After recovery from an attack of severe ABP, patients require close follow-up because late complications are common. Currently, no single test can establish the diagnosis or predict the severity of ABP. A prompt diagnosis requires a high degree of suspicion and clinical acumen. Recognizing patients with severe pancreatitis is an important priority because it affects the type and timing of intervention. The management of these patients requires close clinical observation and a multidisciplinary approach between the surgeon, radiologist, gastroenterologist, and intensivist.

The effect of glutamine-enriched enteral nutrition on intestinal permeability in very-low-birth-weight infants: a randomized controlled trial

BACKGROUND

Very-low-birth-weight (VLBW) infants are susceptible to glutamine depletion. Glutamine depletion has negative effects on intestinal integrity. The lower infection rate in VLBW infants receiving glutamine-enriched enteral nutrition may originate from improved intestinal integrity, as reflected by decreased intestinal permeability. The aim of our study was to investigate whether glutamine-enriched enteral nutrition in VLBW infants enhances the normal decrease in intestinal permeability, as measured by the sugar absorption test (SAT).

METHODS

In a double-blind, randomized, placebo-controlled trial, VLBW infants (gestational age <32 weeks or birth weight <1,500 g) received enteral glutamine supplementation (0.3 g/kg/d) or an isonitrogenous placebo supplementation (alanine) between days 3 and 30 of life. Intestinal permeability, determined from the urinary lactulose/mannitol (L/M) ratio after an oral dose of lactulose and mannitol, was assessed at 4 time points: before the start of the study, and at days 7, 14, and 30 of life.

RESULTS

At least 2 SATs were performed in 45/52 (86%) and 45/50 (90%) infants in the glutamine-supplemented and control groups, respectively. Baseline patient and nutrition characteristics were not different between the groups. There was no effect of glutamine-enriched enteral nutrition on the decrease of the L/M ratio between the start and end of the study (p = .78). In both treatment groups, median urinary lactulose concentrations decreased (p < .001), whereas median urinary mannitol concentrations increased (p = .003).

CONCLUSIONS

Glutamine-enriched enteral nutrition does not enhance the postnatal decrease in intestinal permeability in VLBW infants. Any beneficial effect of glutamine may involve other aspects of intestinal integrity; for example, modulation of the intestinal inflammatory response.

Early nasogastric feeding in predicted severe acute pancreatitis: A clinical, randomized study

OBJECTIVE

To compare the efficacy and safety of early, nasogastric enteral nutrition (EN) with total parenteral nutrition (TPN) in patients with predicted severe acute pancreatitis (SAP).

SUMMARY BACKGROUND DATA

In SAP, the magnitude of the inflammatory response as well as increased intestinal permeability correlates with outcome. Enteral feeding has been suggested superior to parenteral feeding due to a proposed beneficial effect on the gut barrier.

METHODS

Fifty patients who met the inclusion criteria were randomized to TPN or EN groups. The nutritional regimen was started within 24 hours from admission and EN was provided through a nasogastric tube. The observation period was 10 days. Intestinal permeability was measured by excretion of polyethylene glycol (PEG) and concentrations of antiendotoxin core antibodies (Endocab). Interleukins (IL)-6 IL-8, and C-reactive protein (CRP) were used as markers of the systemic inflammatory response. Morbidity and feasibility of the nutritional route were evaluated by the frequency of complications, gastrointestinal symptoms, and abdominal pain.

RESULTS

PEG, Endocab, CRP, IL-6, APACHE II score, severity according to the Atlanta classification (22 patients), and gastrointestinal symptoms or abdominal pain did not significantly differ between the groups. The incidence of hyperglycemia was significantly higher in TPN patients (21 of 26 vs. 7 of 23; P < 0.001). Total complications (25 vs. 52; P = 0.04) and pulmonary complications (10 vs. 21; P = 0.04) were significantly more frequent in EN patients, although complications were diagnosed dominantly within the first 3 days.

CONCLUSION

In predicted SAP, nasogastric early EN was feasible and resulted in better control of blood glucose levels, although the overall early complication rate was higher in the EN group. No beneficial effects on intestinal permeability or the inflammatory response were seen by EN treatment.

Total parenteral nutrition-related gastroenterological complications

Total parenteral nutrition is a life saving therapy for patients with chronic gastrointestinal failure, being an effective method for supplying energy and nutrients when oral or enteral feeding is impossible or contraindicated. Clinical epidemiological data indicate that total parenteral nutrition may be associated with a variety of problems. Herein we reviewed data on the gastroenterological tract regarding: (i) total parenteral nutrition-related hepatobiliary complications; and (ii) total parenteral nutrition-related intestinal complications. In the first group, complications may vary from mildly elevated liver enzyme values to steatosis, steatohepatitis, cholestasis, fibrosis and cirrhosis. In particular, total parenteral nutrition is considered to be an absolute risk factor for the development of biliary sludge and gallstones and is often associated with hepatic steatosis and intrahepatic cholestasis. In general, the incidence of total parenteral nutrition-related hepatobiliary complications has been reported to be very high, ranging from 20 to 75% in adults. All these hepatobiliary complications are more likely to occur after long-term total parenteral nutrition, but they seem to be less frequent, and/or less severe in patients who are also receiving oral feeding. In addition, end-stage liver disease has been described in approximately 15-20% of patients receiving prolonged total parenteral nutrition. Total parenteral nutrition-related intestinal complications have not yet been adequately defined and described. Epidemiological studies intended to define the incidence of these complications, are still ongoing. Recent papers confirm that in both animals and humans, total parenteral nutrition-related intestinal complications are induced by the lack of enteral stimulation and are characterised by changes in the structure and function of the gut. Preventive suggestions and therapies for both these gastroenterological complications are reviewed and reported in the present review.

Review article: intestinal failure

Intestinal failure is a specific disease entity resulting from intestinal resection or disease-associated malabsorption and characterized by the inability to maintain protein-energy, fluid, electrolyte or micronutrient balance. We performed a MEDLINE search (1966-2006) to identify relevant articles, using keywords intestinal failure, parenteral or enteral nutrition, intestinal fistula and short bowel syndrome. Causes of intestinal failure are varied, with self-limiting or 'Type 1' intestinal failure occurring relatively commonly following abdominal surgery, necessitating short-term fluid or nutritional support. The rarer, 'Type 2' intestinal failure, is associated with septic, metabolic and complex nutritional complications, usually following surgical resection in patients with Crohn's or mesenteric vascular disease. A multidisciplinary approach to the management of patients with Type 2 intestinal failure is crucial: resolution of sepsis is required before adequate nutritional repletion can be achieved, and it is important to optimize nutritional status, not only through enteral or parenteral supplementation, but also by addressing complications of short bowel syndrome, before considering definitive surgical reconstruction. A structured approach to the management of Type 2 intestinal failure should reduce the likelihood of these complex patients developing 'Type 3' intestinal failure, which is characterized by the need for long-term parenteral nutrition.

NICHD: AAP workshop on neonatology research and training areas of research in neonatal gastroenterology

Future research in neonatal and developmental gastroenterology should include inquiry well beyond finding a cure or better preventative measures against necrotizing enterocolitis. The gastrointestinal (GI) tract acts not only as a digestive-absorptive organ; it also serves major endocrine and neural functions. It encompasses a vast surface area exposed to the external environment and plays a major role in both innate and adaptive immunity. Numerous short- and long-term health benefits could be derived from a better understanding of the developing GI tract.

Fluid resuscitation and nutritional support during severe acute pancreatitis in the past: what have we learned and how can we do better?

BACKGROUND/AIMS

Severe acute pancreatitis is associated with microcirculatory impairment, increased gut permeability and metabolic changes. The aim of the present study was to evaluate initial fluid resuscitation and nutritional support versus outcome in patients with severe acute pancreatitis.

METHODS

All cases of acute pancreatitis admitted 1994-2003 were analyzed retrospectively. The inclusion criteria of severe acute pancreatitis were organ failure and/or local complications according to the Atlanta classification system. Mortality was used as outcome measure.

RESULTS

Ninty-nine patients were included in the study. The hospital mortality was 17%. Hypovolemia at arrival was found in 13% (13/99) and correlated with increased hospital mortality (P=0.009). During the first three days in average 11000+/-4100 ml of fluids and 1470+/-820 calories were administered. Total parental nutrition was given to 73% (69/95) and enteral nutrition served as a complement in 29% (28/95) of the patients. Hyperglycemia was seen in 61% (55/90) of the patients and insulin was administered to 53% (29/55) at an average glucose level of 19+/-3 mmol/l. The intake of oral food was reintroduced in average 15+/-9 days after admission and was interrupted in 17% (13/75) because of pain relapse.

CONCLUSION

A nutritional treatment regime in severe acute pancreatitis including a moderate and hypocaloric initial fluid resuscitation, parental nutrition as the preferred route for nutritional support and a non-strict glucose control, with an associated mortality of 17%, indicates several modes of improving outcome.

ESPEN Guidelines on Enteral Nutrition: Pancreas

The two major forms of inflammatory pancreatic diseases, acute and chronic pancreatitis, require different approaches in nutritional management, which are presented in the present guideline. This clinical practice guideline gives evidence-based recommendations for the use of ONS and TF in these patients. It was developed by an interdisciplinary expert group in accordance with officially accepted standards and is based on all relevant publications since 1985. The guideline was discussed and accepted in a consensus conference. In mild acute pancreatitis enteral nutrition (EN) has no positive impact on the course of disease and is only recommended in patients who cannot consume normal food after 5-7 days. In severe necrotising pancreatitis EN is indicated and should be supplemented by parenteral nutrition if needed. In the majority of patients continuous TF with peptide-based formulae is possible. The jejunal route is recommended if gastric feeding is not tolerated. In chronic pancreatitis more than 80% of patients can be treated adequately with normal food supplemented by pancreatic enzymes. 10-15% of all patients require nutritional supplements, and in approximately 5% tube feeding is indicated.

The role of polyamines in glucagon-like peptide-2 prevention of TPN-induced gut hypoplasia

Total parenteral nutrition (TPN) of rats has been demonstrated to produce hypoplasia of gut mucosa, and to be associated with reduced immune response and elevated translocation of bacteria from gut to mesenteric lymph nodes, spleen and liver. Treatment of rats being maintained on TPN with the proglucagon fragment, glucagon-like peptide-2 (GLP-2), has been shown to totally prevent small intestine mucosal hypoplasia. In the present study, we found that depletion of polyamines with alpha-difluromethylornithine (DFMO) significantly reduced the efficacy of GLP-2 in preserving gut mucosa in rats maintained on TPN for 8 days. Co-infusion of GLP-2 with TPN prevented loss of protein and mucosa in duodenum, jejunum and ileum, but not in colon. Addition of DFMO to the infusate prevented the protective effects of GLP-2 in the duodenum and jejunum. In the jejunum, putrescine and spermidine were reduced in DFMO-treated rats, while the ileum exhibited reductions of these polyamines in rats infused with TPN or TPN plus GLP-2. DFMO infusion further reduced these polyamines in the ileum, while levels of spermine were increased. Concentrations of ornithine decarboxylase were elevated in jejunum of rats infused with TPN or TPN plus GLP-2, but were reduced significantly in DFMO-treated rats. These results suggest that normal levels of polyamines are necessary for the expression of GLP-2-induced hyperplasia. Differential effects of GLP-2 and DFMO across gut segments may relate to regional differences in proliferative and anti-apoptotic effects of the treatments.

Glutamine-enriched total parenteral nutrition in patients with inflammatory bowel disease

BACKGROUND

Studies in animal models of inflammatory bowel disease (IBD) suggest that supplementation of total parenteral nutrition with glutamine (gln), a conditionally essential amino acid in catabolic conditions, increases gln plasma concentrations, reduces intestinal damage, improves nitrogen balance and may improve the course of the disease. However, human data supporting this assumption are missing.

METHODS

A total of 24 consecutive patients with an acute exacerbation of IBD (19 Crohn's disease; five ulcerative colitis) and scheduled for total parenteral nutrition (TPN) (>7 days) were randomised. Parallel to a standardised anti-inflammatory therapy, the patients received either a TPN with 1.5 g/kg body weight of a standard amino acid or an isonitrogenic, isocaloric TPN with 1.2 g/kg body weight of a standard amino acid and 0.3 g/kg L-alanine-L-glutamine. Primary end points were gln plasma concentrations and intestinal permeability assessed by urinary lactulose and D-xylose ratio.

RESULTS

Gln plasma levels did not differ significantly in either group throughout the study. Intestinal permeability did not change within 7 days either with or without gln supplementation (Delta-lactulose/xylose ratio: 0.01+/-0.05 (gln+) vs 0.02+/-0.1 (gln-)). The observed changes in inflammatory and nutritional parameters, and also disease activity, length of TPN and hospital stay, were independent of glutamine substitution. Five (41%) patients in the gln+ group and three (25%) patients in the gln- group needed surgical intervention.

CONCLUSION

Although limited by the sample size, these results do not support the hypothesis that glutamine substitution has an obvious biochemical or clinical benefit in patients with active IBD scheduled for total parenteral nutrition.

Mechanisms of enteral nutrient-enhanced intestinal adaptation

The role of enteral nutrients in maintaining small intestinal structure and function is well established. Evidence that enteral nutrients induce intestinal adaptation include the structural and functional gradient along the length of the healthy intestine, the atrophy and functional compromise induced by fasting and parenteral nutrition, and the enhanced adaptive capacity of the distal intestine following partial enterectomy. Key mechanisms contributing to enteral nutrient-induced intestinal adaptation include nonspecific luminal stimulation and that provided by specific nutrients, "functional workload" induced by polymeric nutrients, potential stimulation of pancreaticobiliary secretions, secretion of humoral mediators, and induction of intestinal hyperemia.

Glutamine: do the data support the cause for glutamine supplementation in humans?

This review examines the preclinical rationale for using glutamine supplements and reviews the prospective randomized trials using glutamine to improve outcomes in patients. A special role for glutamine in gut physiology and in management of a variety of serious illnesses has been suggested, because it is the most abundant extracellular amino acid, and is used at high rates by the gut, liver, central nervous system, and immune cells. A state of relative Gln deficiency has been postulated in humans based on the decrease in plasma Gln in acute critical illness, but the decrease in plasma Gln is not specific for that amino acid, predicts only poorer outcome, and has not been validated to identify a deficiency state. Current evidence does not necessarily predict a special need or role for Gln in critical illness. Clinical efficacy of supplemental Gln has been difficult to demonstrate, possibly related to the lack of a Gln deficiency state, the wide range of end points used that reflect the lack of certainty of the predicted effect of supplementation, the heterogeneous patient populations studied, the lack of stable clinical course during the study, the lack of adequate power, and the relatively short follow-up period. Prospective randomized clinical trials of Gln supplementation were reviewed in patients with short-bowel syndrome, during cancer chemotherapy and in bone marrow transplantation, and in surgical, burn, and intensive care unit patients. No firm recommendation can be made at this time. Future studies should seek to develop a more standard and stable design for intervention in sufficiently powered studies.

Nutrition in pancreatic diseases

The pancreas plays a major role in nutrient digestion. Therefore, in both acute and chronic pancreatitis, exocrine and endocrine pancreatic insufficiency can develop, impairing digestive and absorptive processes. These changes can lead to malnutrition over time. In parallel to these changes, decreased caloric intake and increased metabolic activity are often present. Nutritional deficiencies negatively affect outcome if they are not treated. Nutritional assessment and the clinical severity of the disease are important for planning any nutritional intervention. In severe acute pancreatitis, enteral nutrition with a naso-jejunal feeding tube and a low molecular diet displays clear advantages compared to parenteral nutrition. Infectious complications, length of hospital stay and the need for surgery are reduced. Furthermore, enteral nutrition is less costly than parenteral nutrition. Parenteral nutrition is reserved for patients who do not tolerate enteral nutrition. Abstinence from alcohol, dietary modifications and pancreatic enzyme supplementation is sufficient in over 80% of patients with chronic pancreatitis. In addition, oral supplements are helpful. Enteral nutrition can be necessary if weight loss continues. Parenteral nutrition is very seldom used in patients with chronic pancreatitis.

Intestinal Adaptation in Short Bowel Syndrome

Short bowel syndrome occurs when there is insufficient length of the small intestine to maintain adequate nutrition and/or hydration status without supplemental support. This syndrome most frequently occurs following extensive surgical resection of the intestine, and the extent of adaptation depends on the anatomy of the resected bowel and the amount of bowel remaining. Following resection, the intestinal tissue undergoes morphologic and functional changes to compensate for the lost function of the resected bowel. These changes are mediated by multiple interactive factors, including intraluminal and parenteral nutrients, gastrointestinal secretions, hormones, cytokines, and growth factors, many of which have been well characterized in animal models. The amount of small bowel remaining is the most important predictor of adaptive potential; neither structural nor functional adaptative changes have been demonstrated in humans or animal models with more extreme resections resulting in an end-jejunostomy. The current understanding of these processes has led to the recent use of supplemental hormones, such as growth hormone and glucagon-like peptide 2, in intestinal rehabilitation programs and may lead to the development of pharmacologic agents designed to augment the innate adaptive response.

Insulin-like growth factor-I (IGF-I) attenuates jejunal atrophy in association with increased expression of IGF-I binding protein-5 in parenterally fed mice

Total parenteral nutrition (TPN) induces dramatic mucosal hypoplasia in rat small intestine that is attenuated by insulin-like growth factor-I (IGF-I). Our aim was to determine the extent of TPN-induced intestinal atrophy and its response to infusion of IGF-I in mice. Male C57BL/6 mice (18-22 g) were maintained with TPN, TPN plus co-infusion of recombinant human IGF-I [2.5 mg/(kg . d)] or oral feeding for 5 d. Body weights did not differ among the groups although serum IGF-I was increased by 78% with IGF-I infusion. IGF-I prevented the significant 25% reduction in mass of the intact small intestine due to TPN compared with oral feeding. Greater TPN-induced atrophy was noted in duodenum and jejunum than ileum. Jejunal atrophy induced by TPN reflected significant decreases in muscularis mass and concentrations of protein and DNA; mucosal cellularity was not altered by TPN. TPN induced a significant decrease in jejunal muscularis width that was reversed by IGF-I with no differences in mucosal villus height and crypt depth. Local expression of IGF-I binding protein (IGFBP)-5 positively modulates the intestinotrophic effects of IGF-I. Jejunal atrophy due to TPN and growth due to IGF-I were directly associated with expression of IGFBP-5 mRNA. TPN decreased IGFBP-5 mRNA by 60% and IGF-I increased IGFBP-5 mRNA by 200% with no change in IGF-I mRNA compared with oral feeding. In summary, TPN induces significant 25% atrophy of the mouse small intestine that is attenuated by IGF-I in association with increased expression of IGFBP-5. Compared with rats, TPN-induced atrophy is less severe and occurs primarily in the jejunal muscularis layer in mice.

Nondiarrheal Disorders of the Gastrointestinal Tract in Neonatal Foals

Neonates can have a variety of gastrointestinal disorders, primary and secondary in nature. Important primary disorders include con-genital abnormalities and meconium retention. One of the most important secondary lesions is generalized ileus. Gastric ulceration can occur as a primary or secondary event. This article addresses the pathophysiology, diagnosis, and treatment of gastrointestinal problems commonly observed in neonatal foals.

Effects of total parenteral nutrition on rat enteric nervous system, intestinal morphology, and motility

Total parenteral nutrition (TPN) is often crucial for patients not being able to feed enterally or having intestinal absorptive deficits. Enteral nutrition is, however, frequently regarded vital for maintaining functional and structural intestinal integrity. The aim of this study was to investigate possible effects of TPN on rat distal small intestine compared to enterally fed identically housed controls, regarding the enteric nervous system (ENS), motility in vitro, and morphology. This study shows that motor responses evoked by electrical stimulation or exposure to vasoactive intestinal peptide (VIP), pituitary adenylate cyclase activating peptide-27 (PACAP-27), and nitric oxide (NO) donor were unchanged. By using immunohistochemistry, the numbers of submucous (P < 0.05) and myenteric (P < 0.05) nerve cells were found to increase, expressed as numbers per unit length. The percentage of neurons expressing VIP, PACAP-27, NO-synthase, and galanin remained unchanged, however. By in situ hybridization the number of submucous neurons expressing neuropeptide Y-mRNA was found to decrease (P < 0.05); the other populations were unaltered. Morphometry revealed an increased submucosal thickness (P < 0.05), while intestinal circumference markedly decreased (P < 0.0001) in TPN-treated rats. In conclusion, TPN treatment resulted in reduced intestinal circumference leading to condensation of enteric neurons. No marked changes in neurotransmitter expression of the enteric neurons or in motor activity were noted.

Mucosal adaptation to enteral nutrients is dependent on the physiologic actions of glucagon-like peptide-2 in mice

BACKGROUND & AIMS

Our understanding of the intestinotropic actions of glucagon-like peptide-2 (GLP-2)(1-33) is based on pharmacologic studies involving exogenous administration. However, the physiologic role of GLP-2 in mucosal growth and adaptation to nutritional stimulation remains poorly understood.

METHODS

The properties of GLP-2(3-33), a GLP-2(1-33) metabolite, were determined in baby-hamster kidney cells transfected with the mouse GLP-2 receptor complementary DNA and in isolated murine intestinal muscle strips. To investigate the role of endogenous GLP-2(1-33) in gut adaptation, GLP-2(3-33) was administered to mice that were re-fed for 24 hours after 24 hours of fasting, and the small intestine was analyzed. GLP-2(3-33) also was injected into rats for analysis of circulating GLP-2(1-33) levels.

RESULTS

GLP-2(3-33) antagonized the actions of GLP-2(1-33) in vitro and ex vivo. Fasting mice exhibited small intestinal atrophy (37% +/- 1% decrease in small intestinal weight, 19% +/- 2% decrease in crypt-villus height, and 99% +/- 35% increase in villus apoptosis, P < .05-.01). Adaptive growth in re-fed mice restored all these parameters, as well as crypt-cell proliferation, to normal control levels (P < .05 vs. fasting); these adaptive changes were prevented partially or completely by co-administration of GLP-2(3-33) to refeeding mice (by 32% +/- 19% to 103% +/- 15%, P < .05-.01 vs re-fed mice). Exogenous GLP-2(3-33) did not affect endogenous GLP-2(1-33) levels.

CONCLUSIONS

These data show that endogenous GLP-2 regulates the intestinotropic response in re-fed mice through modulation of crypt-cell proliferation and villus apoptosis. GLP-2 is therefore a physiologic regulator of the dynamic adaptation of the gut mucosal epithelium in response to luminal nutrients.

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.

Enteral feeding for high-risk neonates: a digest for nurses into putative risk and benefits to ensure safe and comfortable care

Enteral feeding is considered a relatively safe method of providing nutritional support to high-risk neonates. Nonetheless, there are associated risks, which can be classified as follows: factors to consider before initiating enteral feeding; feeding tube placement; delivery of milk feedings; and gastrointestinal, environmental, and technical factors. For each classification, this article highlights adverse consequences and synthesizes the literature for evidence-based nursing practice recommendations, which are summarized in the "Conclusion" section. Many gaps are identified in the research literature, and directions for future research are described to ensure safe and comfortable care for high-risk neonates receiving enteral feedings.

Enteral glutamine but not alanine maintains small bowel barrier function after ischemia/reperfusion injury in rats

We previously demonstrated that glucose and glutamine, solutes metabolized by the gut, replenish ATP and enhance gut function compared with alanine, a solute not metabolized by the gut, following mesenteric ischemia/reperfusion (I/R). The purpose of the present study was to determine if the nonmetabolizable solute alanine differentially modulates cytoskeletal organization and paracellular small intestinal permeability compared with the metabolizable solutes glucose and glutamine following mesenteric I/R. At laparotomy, rats had jejunal sacs filled with 10 mM glucose, glutamine, alanine, or magnesium sulfate (5 mm, osmotic control) followed by superior mesenteric artery clamping for 60 min and 30 min of reperfusion or sham laparotomy. Jejunum was harvested for evaluation by deconvolution microscopy, fluorescent measurement of F:G actin ratio, or mounted in an Ussing chamber for determination of intestinal permeability. Deconvolution microscopy revealed that the actin cytoskeleton was preserved by enteral glutamine, comparable to shams, but disrupted by enteral alanine. Glucose and controls resulted in comparable disruption, which was less than that with alanine. The F:G actin ratio was highest for glutamine and lowest for alanine; glucose was comparable to controls. Intestinal permeability was highest for alanine and lowest for glutamine, which was comparable to shams. Permeability following glucose and controls was higher than that following glutamine but lower than that following alanine. The nonmetabolizable solute alanine resulted in disruption of the actin cytoskeleton and enhanced intestinal permeability under conditions of mesenteric I/R. The metabolizable solute glutamine was protective under these conditions, whereas glucose exerted minimal effect on the integrity of the cytoskeleton and intestinal permeability. The individual components of enteral diets may differentially modulate intestinal barrier function, which could have important implications when administered to critically injured patients.

L-Glutamine ameliorates acetaldehyde-induced increase in paracellular permeability in Caco-2 cell monolayer

Role of L-glutamine in the protection of intestinal epithelium from acetaldehyde-induced disruption of barrier function was evaluated in Caco-2 cell monolayer. L-Glutamine reduced the acetaldehyde-induced decrease in transepithelilal electrical resistance and increase in permeability to inulin and lipopolysaccharide in a time- and dose-dependent manner; d-glutamine, L-aspargine, L-arginine, L-lysine, or L-alanine produced no significant protection. The glutaminase inhibitor 6-diazo-5-oxo-L-norleucine failed to affect the L-glutamine-mediated protection of barrier function. L-Glutamine reduced the acetaldehyde-induced redistribution of occludin, zonula occludens-1 (ZO-1), E-cadherin, and beta-catenin from the intercellular junctions. Acetaldehyde dissociates occludin, ZO-1, E-cadherin, and beta-catenin from the actin cytoskeleton, and this effect was reduced by L-glutamine. L-Glutamine induced a rapid increase in the tyrosine phosphorylation of EGF receptor, and the protective effect of L-glutamine was prevented by AG1478, the EGF-receptor tyrosine kinase inhibitor. These results indicate that L-glutamine prevents acetaldehyde-induced disruption of the tight junction and increase in the paracellular permeability in Caco-2 cell monolayer by an EGF receptor-dependent mechanism.

Effect of parenteral and enteral nutrition combined with octreotide on pancreatic exocrine secretion of patients with pancreatic fistula

AIM: To evaluate the effect of parenteral and enteral nutrition combined with octreotide on pancreatic exocrine secretion of the patients with pancreatic fistula.

METHODS: Pancreatic juice, drained directly from the pancreatic fistula, was collected, and the volume, protein, amylase, HCO₃^-, K⁺, Na⁺ and Cl^- were determined on d 1, 4 and 7 before and after 7-d treatment with octreotide, respectively.

RESULTS: No differences in exocrine pancreatic secretion were observed during the enteral and parenteral nutrition period (t = 2.03, P > 0.05); there were significant decreases in pancreatic juice secretion volume, protein, amylase, HCO₃^-, K⁺, Na⁺ and Cl^- after parenteral and enteral nutrition combined with octreotide compared with octreotide pretreatment (t = 4.14, P < 0.05).

CONCLUSION: There is no stimulatory effect on the pancreatic secretion by intrajejunal nutrition and parenteral nutrition. Octreotide is effective on the reduction of pancreatic fistula output.

Glucagon-like peptide-2 induces intestinal adaptation in parenterally fed rats with short bowel syndrome

Glucagon-like peptide-2 (GLP-2) is an intestinal trophic enteroendocrine peptide that is associated with intestinal adaptation following resection. Herein, we investigate the effects of GLP-2 in a total parenteral nutrition (TPN)-supported model of experimental short bowel syndrome. Juvenile Sprague-Dawley rats underwent a 90% small intestinal resection and jugular catheter insertion. Rats were randomized to three groups: enteral diet and intravenous saline infusion, TPN only, or TPN + 10 microg.kg(-1).h(-1) GLP-2. Nutritional maintenance was isocaloric and isonitrogenous. After 7 days, intestinal permeability was assessed by quantifying the urinary recovery of gavaged carbohydrate probes. The following day, animals were euthanized, and intestinal tissue was processed for morphological and crypt cell proliferation (CCP) analysis, apoptosis (caspase-3), and expression of SGLT-1 and GLUT-5 transport proteins. TPN plus GLP-2 treatment resulted in increased bowel and body weight, villus height, intestinal mucosal surface area, CCP, and reduced intestinal permeability compared with the TPN alone animals (P < 0.05). GLP-2 treatment induced increases in serum GLP-2 levels and intestinal SGLT-1 expression (P < 0.01) compared with either TPN or enteral groups. No differences were seen in the villus apoptotic index between resection groups. Enterally fed resected animals had a significant decrease in crypt apoptotic indexes compared with nontreated animals. This study demonstrates that GLP-2 alone, without enteral feeding, stimulates indexes of intestinal adaptation. Secondly, villus hypertrophy associated with adaptation was predominantly due to an increase in CCP and not to changes in apoptotic rates. Further studies are warranted to establish the mechanisms of action and therapeutic potential of GLP-2.

Nutritional support in critical care

Despite the key role of nutrition in health and the almost universal use of supplemental feeding in the ICU, there is a lack of high-quality evidence to guide clinical practice. Enteral nutrition is superior to TPN in almost all circumstances and most patients in the ICU can be fed successfully by this route. There is little evidence to support the use of special feeds and the role of immunonutrients remains unproven. Nutritional support cannot completely prevent the adverse effects of catabolic illness and overfeeding should be avoided.

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.

Parenteral versus early intrajejunal nutrition: Effect on pancreatitic natural course, entero-hormones release and its efficacy on dogs with acute pancreatitis

AIM: To evaluate the effect of early intrajejunal nutrition (EIN) on the natural course, entero-hormone secretion and its efficacy on dogs with acute pancreatitis.

METHODS: An acute pancreatitis model was induced by injecting 1 mL/kg of combined solution (2.5% sodium taurocholate and 8000-10000 BAEE units trypsin/mL) into the pancreas via pancreatic duct. Fifteen dogs were divided into parenteral nutrition (PN) group and EIN group. Two groups were isonitrogenous and isocaloric. EIN was used at postoperative 24 h. Serum glucose, calcium, amylase and lysosomal enzymes were determined before and 1, 4, 7 d after acute pancreatitis was induced. All the dogs were injected 50 uCi ¹²⁵I-BSA 4 h before sacrificed on the 7^th day. The ¹²⁵I-BSA index of the pancreas/muscle, pancreas/blood, and pancreas pathology score (PPS) were determined. The peripheral plasma cholecystokinin (CCK), secretin (SEC) and gastrin were measured by ELISA and RIA, and was quantitative analysis of pancreatic juice and amylase, pancreatolipase and HCO₃^-, Cl^-, Na⁺ and K⁺ performed by an autochemical analyzer at 30, 60, 120 and 180 min after beginning PN or EIN on the first day.

RESULTS: There was no difference between two groups in the contents of serum calcium, amylase and lysosomal enzymes, ¹²⁵I-BSA index of pancreas/muscle and pancreas/blood and PPS. The contents of CCK and gastrin in EIN were higher than those in PN group at 60 and 120 min (P < 0.05). The content of SEC post-infusion of nutrition solution was higher than that of pre-infusion of nutrition solution in both groups, and only at 60 min SEC in EIN group was higher than that in PN group. The content of gastrin in EIN was higher than that in PN group at 120 and 180 min (P < 0.05). The changes of pancreatic juice, amylase, pancreatolipase and HCO₃^-, Cl^-, Na⁺ and K⁺ between two groups did not reach significantly statistical difference (P > 0.05).

CONCLUSION: EIN does not stimulate entero-hormone and pancreatic juice secretion, and enzyme-protein synthesis and release. EIN has no effect on the natural course of acute pancreatitis.

Glycyl-glutamine-supplemented long-term total parenteral nutrition selectively improves structure and function in heterotopic small-bowel autotransplantation in the pig

Marked atrophy and impaired absorptive and barrier function occur in transplanted small intestinal graft during total parenteral nutrition (TPN), TPN is required by all the patients after small bowel transplantation (SBT). Glutamine (Gln) is a conditional indispensable amino acid that is not included in regimens for parenteral nutrition because of its chemical instability in aqueous solution. Glutamine-containing dipeptide, however, is heat-stable. With this study, we determine whether the glycyl-glutamine-supplemented long-term TPN improves mucosal structure and function in heterotopic transplanted small intestinal graft in the pig. Ten outbred pigs, randomly divided into two groups, underwent heterotopic small bowel autotransplantation. In the STPN group, the animals received standard TPN without glycyl-glutamine (Gly-Gln) and in the GTPN group, the animals received isonitrogenous (0.3g kg day(-1)) and isocalories (nonprotein calories, 30 kcal kg day(-1)) TPN with Gly-Gln (3% Gln) for 28 days. At the end of TPN, there was no significant difference in the body weight loss between two groups ( P>0.05). The mucosal contents of Gln and protein were significantly higher in the GTPN group than in the STPN group ( P<0.05). The mucosal disaccharidase activities in the homogenate of the graft mucosa of the GTPN group were significantly higher than that of the STPN group ( P<0.05). The villous height, surface area, mucosal thickness were significantly higher in the GTPN group than in the STPN group ( P<0.05). There was no significant difference in crypt depth between the two groups ( P>0.05). These results suggest that glycyl-glutamine-supplemented long-term TPN improves graft mucosal structure in heterotopic autotransplanted small bowel grafts in the pig. Long-term (4 weeks) TPN supplemented with Gln could alleviate small intestinal graft atrophy, but could not completely eliminate atrophy.

GLP-2-mediated up-regulation of intestinal blood flow and glucose uptake is nitric oxide-dependent in TPN-fed piglets 1

BACKGROUND & AIMS

Our aim was to determine whether the intestinotrophic effects of GLP-2 are mediated by acute up-regulation of intestinal substrate utilization in TPN-fed piglets.

METHODS

Twenty-four 12-day-old pigs, fitted with a portal flow probe and carotid, jugular and portal catheters, were fed by TPN for 7 days. On day 8, a group of pigs (n = 8) was infused intravenously with saline (control) for 4 hours and then with GLP-2 (500 pmol x kg(-1) x hour(-1), GLP-2) for 4 hours. (2)H-glucose and (13)C-phenylalanine were infused to estimate their kinetics and protein turnover. Another group (n = 8) received consecutive intravenous infusions of saline, GLP-2, and GLP-2 plus N(G)-Nitro-L-arginine methyl ester (L-NAME, 50 micromol x kg(-1) x hour(-1)) for 4 hours each.

RESULTS

GLP-2 acutely increased portal-drained visceral (PDV) blood flow rate (+25%) and intestinal blood volume (+51%) in TPN-fed piglets. GLP-2 also increased intestinal constitutive nitric oxide synthase (NOS) activity and endothelial NOS protein abundance. GLP-2 acutely increased PDV glucose uptake (+90%) and net lactate production (+79%). Co-infusion of GLP-2 plus L-NAME did not increase either PDV blood flow rate or glucose uptake. GLP-2 increased PDV indispensable amino acid uptake by 220% and protein synthesis by 125%, but did not decrease protein breakdown or phenylalanine oxidation.

CONCLUSIONS

We conclude that in TPN-fed neonatal pigs, GLP-2 acutely stimulates intestinal blood flow and glucose utilization, and this response is nitric oxide-dependent. These findings suggest that GLP-2 may play an important physiological role in the regulation of intestinal blood flow and that nitric oxide is involved in GLP-2 receptor function.

Early enteral immunonutrition in patients with severe sepsis: results of an interim analysis of a randomized multicentre clinical trial

OBJECTIVE

To compare the mortality of critically ill patients given either enteral feeding with an immune-enhancing formula or parenteral nutrition (PN). We report the results of a planned interim analysis on patients with severe sepsis which was undertaken earlier than planned once a meta-analysis suggested excess mortality in patients with severe sepsis given enteral immunonutrition.

DESIGN

Randomised multicentre unblinded controlled clinical trial.

SETTING

Thirty-three General Intensive Care Units in Italy.

PATIENTS AND PARTICIPANTS

Among the 237 recruited patients, 39 had severe sepsis or septic shock; 21 of them received PN.

INTERVENTIONS

Eligible patients received either total PN or enteral nutrition, the latter containing extra L-arginine, omega-3 fatty acids, vitamin E, beta carotene, zinc, and selenium.

MEASUREMENTS AND RESULTS

The primary endpoint for the subgroup analysis on patients with severe sepsis was mortality on Intensive Care Unit (ICU). The ICU mortality of patients with severe sepsis given enteral nutrition (EN) was higher than for those given PN (44.4% vs 14.3%; p=0.039). More patients given EN than patients given PN still had severe sepsis when they died (38.9% vs 9.5%, p=0.055). Recruitment of patients with severe sepsis was subsequently stopped.

CONCLUSIONS

Our results show that enteral immunonutrition, compared to PN, may be associated with excess mortality in patients with severe sepsis.

Pancreatitis

In the past decade, our understanding of the genetic basis, pathogenesis, and natural history of pancreatitis has grown strikingly. In severe acute pancreatitis, intensive medical support and non-surgical intervention for complications keeps patients alive; surgical drainage (necrosectomy) is reserved for patients with infected necrosis for whom supportive measures have failed. Enteral feeding has largely replaced the parenteral route; controversy remains with respect to use of prophylactic antibiotics. Although gene therapy for chronic pancreatitis is years away, our understanding of the roles of gene mutations in hereditary and sporadic pancreatitis offers tantalising clues about the disorder's pathogenesis. The division between acute and chronic pancreatitis has always been blurred: now, genetics of the disorder suggest a continuous range of disease rather than two separate entities. With recognition of pancreatic intraepithelial neoplasia, we see that chronic pancreatitis is a premalignant disorder in some patients. Magnetic resonance cholangiopancreatography and endoscopic ultrasound are destined to replace endoscopic retrograde cholangiopancreatography for many diagnostic indications in pancreatic disease.

Tolerance of simulated amniotic fluid in premature neonates

OBJECTIVE

To assess the tolerance of simulated amniotic fluid enterally administered in premature neonates.

DESIGN

A multicentered, Phase I, dose-escalation trial was accomplished among 30 preterm neonates. Groups of 10 patients received 5, 10, or 20 mL/kg/d enterally of the amniotic fluid solution, divided into every-3-hour dosing, for 3 days.

MAIN OUTCOME MEASURES

Amount and character of emesis, stools, and gastric residuals; changes in abdominal girth; presence of a skin rash; blood pressure instability; the diagnosis of necrotizing enterocolitis (NEC) or intestinal perforation.

RESULTS

Thirty patients were studied: 10 received 5 mL/kg/d, 10 received 10 mL/kg/d, and 10 received 20 mL/kg/d of amniotic solution. Gestational ages ranged from 25 to 31 weeks. The Data Safety and Monitoring Board met after each group of 10 patients completed the study, reviewed the outcome measurements, and recommended continuance of the study. Dosing was discontinued for 3 patients prior to receiving all 24 doses because of gastric residuals (n = 1; 5 mL/kg), stage I NEC (n = 1; 10 mL/kg), or symptomatic patent ductus arteriosus (n = 1; 20 mL/kg). The remaining patients completed the doses with no evidence of intolerance: specifically, no increased gastric residuals, increased abdominal girth, diarrhea, blood pressure change, rash, NEC, or intestinal perforation.

CONCLUSIONS

Enteral administration of an amniotic fluid-like solution to preterm neonates is well tolerated in doses <or=20 mL/kg/d.

Role of luminal nutrients and endogenous GLP-2 in intestinal adaptation to mid-small bowel resection

To elucidate the role of luminal nutrients and glucagon-like peptide-2 (GLP-2) in intestinal adaptation, rats were subjected to 70% midjejunoileal resection or ileal transection and were maintained with total parenteral nutrition (TPN) or oral feeding. TPN rats showed small bowel mucosal hyperplasia at 8 h through 7 days after resection, demonstrating that exogenous luminal nutrients are not essential for resection-induced adaptation when residual ileum and colon are present. Increased enterocyte proliferation was a stronger determinant of resection-induced mucosal growth in orally fed animals, whereas decreased apoptosis showed a greater effect in TPN animals. Resection induced significant transient increases in plasma bioactive GLP-2 during TPN, whereas resection induced sustained increases in plasma GLP-2 during oral feeding. Resection-induced adaptive growth in TPN and orally fed rats was associated with a significant positive correlation between increases in plasma bioactive GLP-2 and proglucagon mRNA expression in the colon of TPN rats and ileum of orally fed rats. These data support a significant role for endogenous GLP-2 in the adaptive response to mid-small bowel resection in both TPN and orally fed rats.

Intraepithelial lymphocyte-derived interferon-gamma evokes enterocyte apoptosis with parenteral nutrition in mice

Total parenteral nutrition (TPN) results in an increase in intraepithelial lymphocyte (IEL)-derived interferon-gamma (IFN-gamma) expression as well as an increase in epithelial cell (EC) apoptosis. This study examined the role that IEL-derived IFN-gamma has in the increase in EC apoptosis. Mice received either TPN or oral feedings for 7 days. Small bowel EC apoptosis significantly rose in mice receiving TPN. The administration of TPN also significantly increased IEL-derived IFN-gamma and Fas ligand (FasL) expression. EC apoptosis in IFN-gamma knockout (IFNKO) mice that received TPN was significantly lower than in wild-type TPN mice. Sensitivity of EC to Fas-mediated apoptosis in IFNKO mice was significantly lower than in wild-type TPN mice. Apoptosis in Fas-deficient and FasL-deficient mice that received TPN was significantly lower than in wild-type mice that received TPN. The TPN-induced increase in IFN-gamma expression appears to result in an increase in Fas-L expression and EC sensitivity to Fas, with a resultant increase in EC apoptosis. This may well be one of the mediators of increased EC apoptosis observed with TPN administration.

Tolerance of a sterile isotonic electrolyte solution containing select recombinant growth factors in neonates recovering from necrotizing enterocolitis

OBJECTIVE

To assess the tolerance of a sterile isotonic electrolyte solution containing select recombinant growth factors enterally administered in neonates who were NPO because of necrotizing enterocolitis (NEC).

STUDY DESIGN

A phase I trial was accomplished among 30 neonates. Patients received 5, 10, or 20 mL enterally of the study solution/kg/day divided into every 3-hour dosing, for 3 days prior to when feedings of milk were to resume. The occurrence of emesis, gastric residuals, diarrhea, bloody stools, abdominal distention, skin rashes and death were sought.

RESULTS

Gestational ages ranged from 25.2 to 41.1 weeks. A total of 16 neonates had Stage IA NEC, six Stage IB, and eight Stage IIA. The solution was well tolerated in all 30; none developed diarrhea, guaiac positive or bloody stools, or abdominal distention. Administration of the solution was not prematurely discontinued in any infant. Two neonates died secondary to late-onset sepsis remote from the study period.

CONCLUSIONS

Enteral administration of a sterile isotonic electrolyte solution containing select recombinant growth factors was well tolerated by neonates with NEC.

Management of severe acute pancreatitis

BACKGROUND

Acute pancreatitis is still associated with significant morbidity and mortality. Current management guidelines are sometimes equivocal, particularly in relation to the surgical treatment of severe disease. This review assesses available investigative and treatment strategies to allow the development of a formalized management approach.

METHODS

A literature review of diagnosis, staging and management of acute pancreatitis was performed.

RESULTS AND CONCLUSION

Recent evidence has helped to clarify the roles of computed tomography, endoscopic retrograde cholangiopancreatography, prophylactic antibiotics, enteral feeding and fine-needle aspiration for bacteriology in the management of acute pancreatitis. Despite a relative shortage of prospective randomized trials there has been a significant change in the surgical management of acute pancreatitis over the past 20 years. This change has been away from early aggressive surgical intervention towards more conservative management, except when infected necrosis is confirmed. A formalized approach, with appropriate use of the various non-surgical and surgical options, is feasible in the management of severe acute pancreatitis.

Enteral administration of hematopoietic growth factors in the neonatal intensive care unit

By 20 wk of gestation, the human fetal gastrointestinal (GI) tract morphologically resembles that of the term infant, but functional development is limited before 26 wk. By 30 wk of gestation, the fetus has the capacity for limited digestion and enteral absorption. GI growth and development continue postnatally. Trophic factors, including nutrients, peptides, hormones and growth factors, are recognized as having important influences on the morphology and histology of the developing GI tract. Other trophic factors are important in adaptation and repair following injury. Many such factors are provided in utero via amniotic fluid swallowing and later by human colostrum and milk.

CONCLUSION

This review discusses cytokines with known GI trophic effects, either in vitro or in vivo, and focuses on those cytokines that have been used in the neonatal intensive care unit.

Enteral versus parenteral nutrition for acute pancreatitis

BACKGROUND

Acute pancreatitis creates a catabolic stress state promoting a systemic inflammatory response and nutritional deterioration. Adequate supply of nutrients plays an important role to ensure optimum recovery. Total parenteral nutrition (TPN) has been the standard practice for providing exogenous nutrients to patients with severe acute pancreatitis. However, recent data suggest that enteral nutrition (EN) is feasible. Thus, a comparison of EN and TPN in patients with acute pancreatitis needs to be made.

OBJECTIVES

To compare the effect of total parenteral nutrition (TPN) versus enteral nutrition (EN) on mortality, morbidity and length of hospital stay in patient with acute pancreatitis.

SEARCH STRATEGY

Trials were identified by computerized searches of The Cochrane Controlled Trials Register, MEDLINE, and EMBASE. Additional studies were identified and included where relevant by searching Scisearch, the bibliographies of review articles and identified trials, and personal files. The search was undertaken in August, 2000 and updated in September 2002. No language restrictions were applied.

SELECTION CRITERIA

Randomized clinical trials, in which nutrition support with TPN were compared to EN in patients with acute pancreatitis.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. Information was collected on death, length of hospital stay, systemic infection, local septic complications, and other local complications.

MAIN RESULTS

Two trials with a total of 70 participants were included. The relative risk (RR) for death with EN vs TPN was 0.56 (95% CI 0.05 to 5.62). Mean length of hospital stay was reduced with EN (WMD -2.20, 95% CI -3.62 to -0.78). RR for systemic infection with EN vs TPN was 0.61 (95% CI 0.29 to 1.28). In one trial, RR for local septic complications and other local complications with EN vs TPN was 0.56 (95% CI 0.12 to 2.68) and 0.16 (95% CI 0.01 to 2.86) respectively.

REVIEWER'S CONCLUSIONS

Although there is a trend towards reductions in the adverse outcomes of acute pancreatitis after administration of EN, clearly there are insufficient data to draw firm conclusions about the effectiveness and safety of EN versus TPN. Further trials are required with sufficient size to account for clinical heterogeneity and to measure all relevant outcomes.

Oral glutamine in paediatric oncology patients: a dose finding study

OBJECTIVE

The purpose of this study was to determine the most appropriate dose of oral glutamine to use in a further clinical study in paediatric oncology patients.

DESIGN

This was a phase I, pharmokinetic study.

SETTING

The study was carried out at The Yorkshire Regional Centre for Paediatric Oncology and Haematology, St James's University Hospital, Leeds, UK.

SUBJECTS

Thirteen patients undergoing treatment for paediatric malignancy participated in this study. All 13 completed the study.

INTERVENTIONS

The most appropriate dose was determined by patient acceptability and by plasma glutamine and ammonia levels measured at timed intervals after ingestion of a single glutamine dose.

RESULTS

Doses of 0.35, 0.5 and 0.65 g/kg were well tolerated with no untoward plasma glutamine and ammonia levels. One patient was recruited to a higher dose of 0.75 g/kg, but the plasma glutamine and ammonia levels peaked at 2601 and 155 micro mol/l, respectively. The ammonia level was greater than the acceptable upper limit. It was difficult to disperse the glutamine adequately at this dose, resulting in the suspension being found to be unpalatable and therefore no further patients were recruited at this dose.

CONCLUSION

It was concluded that 0.65 g/kg is a safe dose of glutamine to use in a clinical study in paediatric oncology patients.