Enteral glutamine supplementation for very-low-birth-weight infants decreases hospital costs

Unbiasing costs? An appraisal of economic assessment alongside randomized trials in neonatology

Economic evaluations performed alongside randomized controlled trials benefit from the protections against bias inherent in randomization. In this systematic review, we assessed the frequency and quality of economic assessments alongside randomized controlled trials of interventions in neonates published between 1990 and 2016. Over that period, 58 economic assessments were published, corresponding to approximately 2% of RCTs. We noted significant methodological limitations of these studies, including limitation of included costs to the health sector or payer rather than broader categories such as family or community expenditures (81%), short time horizon for cost measurement (less than one year in 60%), lack of reporting of uncertainty (26%), and infrequent analysis of costs and effects in a single metric (combined in 45%). Strategies for improving the quality and frequency of economic evaluations in neonatology are discussed, including selection of appropriate trials, funding, and peer review.

ESPEN guideline on clinical nutrition in the intensive care unit

Following the new ESPEN Standard Operating Procedures, the previous guidelines to provide best medical nutritional therapy to critically ill patients have been updated. These guidelines define who are the patients at risk, how to assess nutritional status of an ICU patient, how to define the amount of energy to provide, the route to choose and how to adapt according to various clinical conditions. When to start and how to progress in the administration of adequate provision of nutrients is also described. The best determination of amount and nature of carbohydrates, fat and protein are suggested. Special attention is given to glutamine and omega-3 fatty acids. Particular conditions frequently observed in intensive care such as patients with dysphagia, frail patients, multiple trauma patients, abdominal surgery, sepsis, and obesity are discussed to guide the practitioner toward the best evidence based therapy. Monitoring of this nutritional therapy is discussed in a separate document.

Nutritional management of the foal with diarrhoea

Diarrhoea is a common problem in the neonatal and suckling foal. In certain circumstances supplemental nutrition is necessary depending on the age of foal, severity of diarrhoea and presence of other systemic manifestations. Nutritional supplementation can be provided either enterally or parenterally. Enteral nutrition is superior to parenteral nutrition because it is the most natural and physiologically sound means to provide nutritional support. Parenteral nutrition may be warranted if the foal is unable to receive or tolerate enteral nutrition. Dextrose alone or with amino acids and lipids can provide appropriate nutrition when enteral feeding is not tolerated. As soon as the foal stabilises enteral feeding can be reintroduced.

Glutamine supplementation to prevent morbidity and mortality in preterm infants

BACKGROUND

Glutamine is a conditionally essential amino acid. Endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress. Evidence exists that glutamine supplementation improves clinical outcomes in critically ill adults. It has been suggested that glutamine supplementation may also benefit preterm infants.

OBJECTIVES

To determine the effects of glutamine supplementation on mortality and morbidity in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, 2015, Issue 12), MEDLINE, EMBASE and Maternity and Infant Care (to December 2015), conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared glutamine supplementation versus no glutamine supplementation in preterm infants at any time from birth to discharge from hospital.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors. We synthesised data using a fixed-effect model and reported typical relative risk, typical risk difference and weighted mean difference.

MAIN RESULTS

We identified 12 randomised controlled trials in which a total of 2877 preterm infants participated. Six trials assessed enteral glutamine supplementation and six trials assessed parenteral glutamine supplementation. The trials were generally of good methodological quality. Meta-analysis did not find an effect of glutamine supplementation on mortality (typical relative risk 0.97, 95% confidence interval 0.80 to 1.17; risk difference 0.00, 95% confidence interval -0.03 to 0.02) or major neonatal morbidities including the incidence of invasive infection or necrotising enterocolitis. Three trials that assessed neurodevelopmental outcomes in children aged 18 to 24 months and beyond did not find any effects.

AUTHORS' CONCLUSIONS

The available trial data do not provide evidence that glutamine supplementation confers important benefits for preterm infants.

Glutamine supplementation to prevent morbidity and mortality in preterm infants

BACKGROUND

Glutamine is a conditionally essential amino acid. Endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress. Evidence exists that glutamine supplementation improves clinical outcomes in critically ill adults. It has been suggested that glutamine supplementation may also benefit preterm infants.

OBJECTIVES

To determine the effects of glutamine supplementation on mortality and morbidity in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, 2015, Issue 12), MEDLINE, EMBASE and Maternity and Infant Care (to December 2015), conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared glutamine supplementation versus no glutamine supplementation in preterm infants at any time from birth to discharge from hospital.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors. We synthesised data using a fixed-effect model and reported typical relative risk, typical risk difference and weighted mean difference.

MAIN RESULTS

We identified 12 randomised controlled trials in which a total of 2877 preterm infants participated. Six trials assessed enteral glutamine supplementation and six trials assessed parenteral glutamine supplementation. The trials were generally of good methodological quality. Meta-analysis did not find an effect of glutamine supplementation on mortality (typical relative risk 0.97, 95% confidence interval 0.80 to 1.17; risk difference 0.00, 95% confidence interval -0.03 to 0.02) or major neonatal morbidities including the incidence of invasive infection or necrotising enterocolitis. Three trials that assessed neurodevelopmental outcomes in children aged 18 to 24 months and beyond did not find any effects.

AUTHORS' CONCLUSIONS

The available trial data do not provide evidence that glutamine supplementation confers important benefits for preterm infants.

The effect of 2 mMol glutamine supplementation on HSP70 and TNF-α release by LPS stimulated blood from healthy children

OBJECTIVE

Glutamine has been shown to promote heat shock protein 70 (HSP70) release both within experimental in vitro models of sepsis (2-10 mM) and in adults post trauma (0.5 g/kg), although the efficacy varies and is dependent on the model used. The effect of glutamine supplementation on HSP70 release in children is less clear. Therefore, the aim of this study was to investigate the effect of 2 mM glutamine added to incubation media on HSP70 and inflammatory mediator release in an in vitro model of paediatric sepsis using whole blood from healthy paediatric volunteers.

METHODS

An in vitro whole blood endotoxin stimulation model using 1 μg/ml lipopolysaccharide (LPS) over a 24 h time period was used to investigate the effects of 2 mM glutamine on HSP70 and inflammatory mediator release in healthy children.

RESULTS

The addition of 2 mM glutamine to the incubation media significantly increased HSP70 release over time (p < 0.05). This was associated with an early pro-inflammatory effect on TNF-α release at 4 h (p < 0.005) which was not seen at 24 h. There was a non significant trend towards higher levels of IL-6 and IL-10 following the addition of 2 mM glutamine, which appears to differ from the response reported in adult and animal models.

CONCLUSION

Glutamine supplementation of incubation media promotes HSP70 and early TNF- α release in an in vitro model using blood samples from healthy children.

Effect of High-Dose Cysteine Supplementation on Erythrocyte Glutathione: A Double-Blinded, Randomized Placebo-Controlled Pilot Study in Critically Ill Neonates

BACKGROUND

This study's objective was to determine if parenteral cysteine when compared with isonitrogenous noncysteine supplementation increases erythrocyte reduced glutathione (GSH) in neonates at high risk for inflammatory injury.

MATERIAL AND METHODS

Neonates with a score for neonatal acute physiology >10 requiring mechanical ventilation and parenteral nutrition (PN) were randomized in a double-blinded, placebo-controlled study to receive parenteral cysteine-HCl (CYS group) or additional PN amino acids (ISO group) at 121 mg/kg/d for ≥7 days. A 6-hour [(13)C2] glycine IV infusion was administered at study week 1 to determine the fractional synthetic rate of GSH (FSR-GSH).

RESULTS

Baseline characteristics were similar between the CYS (n = 17) and ISO groups (n = 21). Erythrocyte GSH and total glutathione concentrations, GSH:oxidized GSH (GSSG), and FSR-GSH after treatment were not different between groups. However, the CYS group had a larger individual positive change in GSH and total glutathione (infusion day - baseline) compared with the ISO group (P = .02 for each). After adjusting for treatment, a lower enrollment weight and rate of red blood cell transfusion were associated with a decreased change in total glutathione and GSH (P < .05 for each).

CONCLUSION

When compared with isonitrogenous noncysteine supplementation, high-dose cysteine supplementation for at least 1 week in critically ill neonates resulted in a larger and more positive individual change in GSH. Smaller infants and those who received transfused blood demonstrated less effective change in GSH with cysteine supplementation. The benefit of cysteine remains promising and deserves further investigation.

Arginyl-glutamine dipeptide or docosahexaenoic acid attenuate hyperoxia-induced lung injury in neonatal mice

OBJECTIVES

Supplementation studies of glutamine, arginine, and docosahexaenoic acid (DHA) have established the safety of each of these nutrients in neonates. However, the potential for a more stable and soluble dipeptide, arginyl-glutamine (Arg-Gln) or DHA, a long-chain ω-3 fatty acid with anti-inflammatory properties, to exert benefits on hyperoxia-induced lung injury has not to our knowledge been investigated. The aim of this study was to investigate whether Arg-Gln dipeptide or DHA could attenuate markers of injury and inflammation in neonatal mouse lungs exposed to hyperoxia.

METHODS

Seven-day-old mouse pups were placed with their dams in 75% oxygen for 5 d. After 5 d of hyperoxic exposure (postnatal days 7-12), pups were removed from hyperoxia and allowed to recover in atmospheric conditions for 5 d (postnatal days 12-17). Mouse pups received Arg-Gln (5 g · kg⁻¹ · d⁻¹) or DHA (5 g · kg⁻¹ · d⁻¹) or saline orally from postnatal days 12 through 17. Histologic changes, myeloperoxidase, lactate dehydrogenase, inflammatory cytokines, and nuclear factor-κB inhibitor levels were checked in each group.

RESULTS

The Arg-Gln and DHA prevented the development of key markers of injury, including histologic changes, myeloperoxidase, lactate dehydrogenase, and inflammatory cytokines interleukin-6 and C-X-C motif ligand 1 (CXCL1)/keratinocyte-derived chemokine (KC). The highly beneficial effects of Arg-Gln on the reversal of oxygen-induced lung damage was associated with restoration of levels of nuclear factor-κB inhibitor.

CONCLUSION

The Arg-Gln and DHA, with protective effects on hyperoxic lung injury in neonatal mice, are promising nutritional adjuncts that may prevent lung damage owing to oxygen toxicity in infants.

Glutamine supplementation to prevent morbidity and mortality in preterm infants

BACKGROUND

Glutamine is a conditionally essential amino acid. Endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress. Evidence exists that glutamine supplementation improves clinical outcomes in critically ill adults. It has been suggested that glutamine supplementation may also benefit preterm infants.

OBJECTIVES

To determine the effects of glutamine supplementation on mortality and morbidity in preterm infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2011, Issue 4), MEDLINE, EMBASE and CINAHL (to November 2011), conference proceedings and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared glutamine supplementation versus no glutamine supplementation in preterm infants at any time from birth to discharge from hospital.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors. We synthesised data using a fixed-effect model and reported typical relative risk, typical risk difference and weighted mean difference.

MAIN RESULTS

We identified 11 randomised controlled trials in which a total of 2771 preterm infants participated. Five trials assessed enteral glutamine supplementation and six trials assessed parenteral glutamine supplementation. The trials were generally of good methodological quality. Meta-analysis did not detect a statistically significant effect of glutamine supplementation on mortality [typical relative risk 0.98 (95% confidence interval 0.80 to 1.18); risk difference 0.00 (95% confidence interval -0.03 to 0.02)] or major neonatal morbidities including the incidence of invasive infection or necrotising enterocolitis. Two trials that assessed neurodevelopmental outcomes at 18 to 24 months did not find any statistically significant differences in various assessments.

AUTHORS' CONCLUSIONS

The available trial data do not provide evidence that glutamine supplementation confers important benefits for preterm infants.

Glutamine supplementation in sick children: is it beneficial?

The purpose of this review is to provide a critical appraisal of the literature on Glutamine (Gln) supplementation in various conditions or illnesses that affect children, from neonates to adolescents. First, a general overview of the proposed mechanisms for the beneficial effects of Gln is provided, and subsequently clinical studies are discussed. Despite safety, studies are conflicting, partly due to different effects of enteral and parenteral Gln supplementation. Further insufficient evidence is available on the benefits of Gln supplementation in pediatric patients. This includes premature infants, infants with gastrointestinal disease, children with Crohn's disease, short bowel syndrome, malnutrition/diarrhea, cancer, severe burns/trauma, Duchenne muscular dystrophy, sickle cell anemia, cystic fibrosis, and type 1 diabetes. Moreover, methodological issues have been noted in some studies. Further mechanistic data is needed along with large randomized controlled trials in select populations of sick children, who may eventually benefit from supplemental Gln.

Molecular cloning, mass spectrometric identification, and nutritional evaluation of 10 coixins in adlay ( Coix lachryma-jobi L.)

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) is regarded as a nutritive food source as well as herbal medicine. The food nutrition is a consequence of its high protein content and superior amino acid composition. From ca. 200 expressed sequence tag (EST) sequences in maturing adlay grains, clones encoding precursor polypeptides of 10 seed storage proteins in the prolamin family, including 8 alpha-coixin isoforms, 1 delta-coixin, and 1 gamma-coixin, were identified. Full-length cDNA fragments encoding these 10 coixins were obtained by PCR cloning. Mass spectrometric analyses confirmed the presence of these 10 coixins in the extract of adlay grain. Calculated amino acid compositions indicate that all 10 coixins are rich in glutamine (>20% in alpha-coixin isoforms, 13.3% in delta-coixin, and 31.2% in gamma-coixin). The 8 alpha-coixin isoforms are low in methionine, cysteine, and lysine (on average, 0.8, 0.6, and 0.1%, respectively). However, the delta-coixin is a sulfur-rich protein (18.2% methionine and 9.1% cysteine), and the gamma-coixin is a nutritive protein composed of 2.0% methionine, 6.6% cysteine, 2.6% lysine, and 8.9% histidine. The company of delta-coixin and gamma-coixin with alpha-coixin isoforms enhances the nutritional value of alday grain for human consumption.

Cytokine responses in very low birth weight infants receiving glutamine-enriched enteral nutrition

OBJECTIVE

Very low birth weight (VLBW) infants receiving glutamine-enriched enteral nutrition may present with a lower infection rate, which may result from enhanced antimicrobial innate or Th1 cytokine responses. We investigated whether glutamine-enriched enteral nutrition in VLBW infants increased these cytokine responses following in vitro stimulation of whole blood cells.

METHODS

In a double-blind, placebo-controlled, randomized controlled trial, VLBW infants (gestational age <32 weeks and/or birth weight <1500 g) received enteral glutamine supplementation (0.3 g x kg(-1) x day(-1)) or isonitrogenous placebo supplementation (alanine) between days 3 and 30 of life. Cytokine responses following in vitro whole blood cell stimulation with anti-(alpha)CD3/alphaCD28 or lipopolysaccharide were analyzed by cytometric bead array at 3 time points: before the start of the study, at day 7 of life, and at day 14 of life.

RESULTS

Baseline patient and nutritional characteristics were not different between groups. At least 2 blood samples were analyzed in 25 of 52 (48%) and 38 of 50 (76%) infants in the glutamine-supplemented and control groups, respectively. Glutamine-enriched enteral nutrition was not associated with significant alterations in cytokine responses (interferon-gamma, tumor necrosis factor-alpha, interleukin [IL]-2, IL-4, IL-5, and IL-10) of peripheral blood cells upon stimulation with either anti-alphaCD3/alphaCD28 or lipopolysaccharide.

CONCLUSIONS

We hypothesize that glutamine-enriched enteral nutrition decreases the infection rate in VLBW infants by influencing the mucosal and not the systemic immune system.

Glutamine supplementation to prevent morbidity and mortality in preterm infants

BACKGROUND

Glutamine endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress. Trials in adults have suggested that glutamine supplementation improves clinical outcomes in critically ill adults. It has been suggested that glutamine supplementation may benefit preterm infants, particularly very low birth weight infants.

OBJECTIVES

To determine the effects of glutamine supplementation on mortality and morbidity in preterm infants.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2007), MEDLINE (1966 - July 2007), EMBASE (1980 - July 2007), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared glutamine supplementation versus no glutamine supplementation in preterm infants at any time from birth to discharge from hospital.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group were used, with separate evaluation of trial quality and data extraction by two authors. Data were synthesised using a fixed effects model and reported using typical relative risk, typical risk difference and weighted mean difference.

MAIN RESULTS

2365 preterm infants have participated in seven randomised controlled trials. All of the participating infants were of very low birth weight. Three trials assessed enteral glutamine supplementation and four trials assessed parenteral glutamine supplementation. The trials were generally of good methodological quality with adequate allocation concealment, blinding of caregivers and assessors to the intervention, and complete or near-complete follow-up of recruited infants. Glutamine supplementation does not have a statistically significant effect on mortality: typical relative risk 0.98 (95% confidence interval 0.80 to 1.20); typical risk difference 0.00 (95% confidence interval -0.03 to 0.02). The only trial that assessed long-term outcomes did not find any statistically significant differences in various assessments of neurodevelopment at 18 months corrected age. Glutamine supplementation does not have a statistically significant effect on other neonatal morbidities including invasive infection, necrotising enterocolitis, time to achieve full enteral nutrition, or duration of hospital stay.

AUTHORS' CONCLUSIONS

The available data from good quality randomised controlled trials indicate that glutamine supplementation does not confer benefits for preterm infants. The narrow confidence intervals for the effect size estimates suggest that a further trial of this intervention is not a research priority.

Total glutamine content in human milk is not influenced by gestational age

BACKGROUND

Glutamine may be a conditionally indispensable amino acid in neonates and should be given in adequate amounts. Reliable information concerning the glutamine content of human milk is lacking.

AIM

To assess total glutamine content in human milk using a novel analytical procedure, and to evaluate the potential influence of time of delivery and lactational stage.

METHODS

The content of free and protein-bound glutamine was assessed in transitional (days 4-7 of lactation) and mature (days 29-34) human milk, after preterm (<35 wk of gestation, n=20) or term (>37 wk, n=20) delivery. Milk samples were obtained by manual expression and stored at <or=70 degrees C. Measurement of protein-bound glutamine was performed after stabilization by bis(1,1-trifluoroacetoxy)iodobenzene (BTI). Free glutamine was detected by HPLC.

RESULTS

There was no difference concerning glutamine content in human milk after term or preterm delivery (median of 5000 vs 4960 micromol/l milk). The protein-bound glutamine content decreased with the duration of lactation (6230 vs 4540 micromol/l milk). Free glutamine accounted for only 3-10% of the protein-bound glutamine content. The free glutamine content showed a high variability after preterm and term delivery.

CONCLUSION

This study presents for the first time data on glutamine intake in preterm and term neonates fed human milk. With these data, it is possible to formulate adequately composed nutritional therapy for infants at risk of glutamine imbalance.

Enteral nutrition and oral nutrition supplements: a review of the economics literature

BACKGROUND

We sought to review the economics literature on enteral nutrition (EN) and oral nutrition supplements (ONS) against the background of an ongoing clinical guideline development.

METHODS

We searched the Health Economic Evaluations Database, the NHS Economic Evaluation Database, and the Cochrane Database of Systematic Reviews.

RESULTS

Enteral vs parenteral nutrition was found to be the most common comparison undertaken. The randomized trial evidence suggests that, in some groups of patients, EN is better in terms of clinical endpoints and/or length of hospital stay. This should translate into a lower mean cost for EN, given the reduced daily cost. These studies should be treated with caution because of their small sample size and poor quality. Costing was often crude and poorly reported, tending to focus on the narrow costs of the nutrition supplements. Only 1 study of a nutrition supplement in the community setting was found.

CONCLUSIONS

There is some evidence to indicate economic advantages of enteral over parenteral nutrition and of immune-enhancing supplements relative to control diet. There is a lack of well-designed studies taking a broad view of relevant comparators, costs, and outcomes. The cost-effectiveness of different forms of nutrition in different patient groups remains to be established.

Glutamine supplementation of parenteral nutrition does not improve intestinal permeability, nitrogen balance, or outcome in newborns and infants undergoing digestive-tract surgery: results from a double-blind, randomized, controlled trial

OBJECTIVE

To assess the effect of isocaloric isonitrogenous parenteral glutamine supplementation on intestinal permeability and nitrogen loss in newborns and infants after major digestive-tract surgery.

SUMMARY BACKGROUND DATA

Glutamine supplementation in critically ill and surgical adults may normalize intestinal permeability, attenuate nitrogen loss, improve survival, and lower the incidence of nosocomial infections. Previous studies in critically ill children were limited to very-low-birthweight infants and had equivocal results.

METHODS

Eighty newborns and infants were included in a double-blind, randomized trial comparing standard parenteral nutrition (sPN; n = 39) to glutamine-supplemented parenteral nutrition (GlnPN; glutamine target intake, 0.4 g kg day; n = 41), starting on day 2 after major digestive-tract surgery. Primary endpoints were intestinal permeability, as assessed by the urinary excretion ratio of lactulose and rhamnose (weeks 1 through 4); nitrogen balance (days 4 through 6), and urinary 3-methylhistidine excretion (day 5). Secondary endpoints were mortality, length of stay in the ICU and the hospital, number of septic episodes, and usage of antibiotics and ICU resources.

RESULTS

Glutamine intake plateaued at 90% of the target on day 4. No differences were found between patients assigned sPN and patients assigned GlnPN regarding any of the endpoints. Glutamine supplementation was not associated with adverse effects.

CONCLUSIONS

In newborns and infants after major digestive-tract surgery, we did not identify beneficial effects of isonitrogenous, isocaloric glutamine supplementation of parenteral nutrition. Glutamine supplementation in these patients therefore is not warranted until further research proves otherwise.

A suplementação de glutamina é benéfica em crianças com doenças graves?

Embora haja vários estudos clínicos randômicos avaliando os benefícios da suplementação de glutamina em pacientes adultos, há pouca informação em pacientes pediátricos, particularmente naqueles com doenças graves. O objetivo deste estudo foi avaliar criticamente os estudos sobre suplementação de glutamina, para verificar os possíveis benefícios clínicos desta suplementação em crianças gravemente doentes. Levou-se a cabo uma pesquisa dos estudos publicados entre 1992 e 2003, do tipo prospectivo, randômico e controlado, conduzidos em pacientes pediátricos gravemente doentes, divididos em dois grupos: o dos que receberam suplementos de glutamina por via enteral ou parenteral, e o dos que receberam placebo. As variáveis de desfecho foram: tempo para atingir oferta plena de dieta enteral, tempo de hospitalização, complicações e mortalidade. Foram utilizadas as bases de dados Medline, LILACS e Cochrane, com as palavras-chave: glutamine, critically ill, trauma, sepsis, burned, injured, bone marrow transplantation, intensive care, mechanical ventilation. Dos 33 estudos inicialmente identificados, 7 preencheram os critérios de inclusão. A análise dos resultados mostrou que nos pacientes suplementados com glutamina, houve melhor aceitação por via enteral e redução do tempo de nutrição parenteral em recém-nascidos, não havendo efeito sobre o tempo de internação, custos hospitalares e mortalidade. Os estudos controlados na faixa etária pediátrica, não permitem que se adote o uso rotineiro da glutamina em crianças gravemente enfermas. O número reduzido de pacientes e a heterogeneidade quanto ao grupo etário, doenças e via de administração são fatores que limitam a interpretação dos resultados.

Glutamine supplementation to prevent morbidity and mortality in preterm infants

BACKGROUND

Glutamine endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress. Trials in adults have suggested that glutamine supplementation improves clinical outcomes in critically ill adults. It has been suggested that glutamine supplementation may benefit preterm infants, particularly very low birth weight infants.

OBJECTIVES

To determine the effects of glutamine supplementation on mortality and morbidity in preterm infants.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2004), MEDLINE (1966 - August 2004), EMBASE (1980 - August 2004), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared glutamine supplementation versus no glutamine supplementation in preterm babies at any time from birth to discharge from hospital.

DATA COLLECTION AND ANALYSIS

We extracted the data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two reviewers, and synthesis of data using relative risk, risk difference and weighted mean difference.

MAIN RESULTS

More than 2300 infants have participated in six randomised controlled trials. All of the participating infants were of very low birth weight. Three trials assessed enteral glutamine supplementation, and three trials assessed parenteral glutamine supplementation. These trials were generally of good methodological quality with adequate allocation concealment, blinding of care-givers and assessors to the intervention, and complete or near-complete follow-up of recruited infants. We found that glutamine supplementation does not have a statistically significant effect on mortality: typical relative risk 0.98 (95% confidence interval 0.80 to 1.21); typical risk difference 0.00 (95% confidence interval -0.03 to 0.03). One of the trials assessed longer term neurodevelopmental outcomes (Poindexter 2004). The investigators reported that they did not find any statistically significant differences in various assessments of neurodevelopment (including Bayley scales) on follow up at 18 months corrected age. We found that glutamine supplementation does not have a statistically significant effect on the incidence of systemic infection (typical relative risk 1.02 (95% confidence interval 0.92 to 1.13); typical risk difference 0.01 (95% confidence interval -0.03 to 0.05)), necrotising enterocolitis (typical relative risk 1.02 (95% confidence interval 0.79 to 1.33); typical risk difference 0.00 (95% confidence interval -0.02 to 0.03)), days to full enteral nutrition (weighted mean difference -1.1 days (95% confidence interval -3.4 to 1.2)), or duration of hospital stay (weighted mean difference 0.65 days (95% confidence interval -2.9 to 4.2)).

AUTHORS' CONCLUSIONS

The available data from good quality randomised controlled trials suggest that glutamine supplementation does not confer clinically significant benefits for preterm infants. The narrow confidence intervals for the effect size estimates suggest that a further trial of this intervention is not a research priority.

The role of early enteral nutrition in protecting premature infants from sepsis

Care of critically ill, preterm infants is a major challenge. Because of their small size and complex health problems, preterm infants require long-term hospitalization in the intensive care unit where they are exposed to serious microorganisms and other antigens that can overwhelm their immature immune systems. As smaller and more fragile preterm infants are surviving NICU care, these infants are at increased risk for nosocomial infections. Although modern antimicrobial agents are invaluable in the management of infection, they can result in biologic stress to the immature physiology of the preterm infant. Nonpharmacologic strategies to enhance the immunocompetence of the preterm immune systems provide another alternative in the management of these infants. Because the gastrointestinal tract is one of the largest immune organs within the body, strategies to maximize its immune functions can improve the outcome of these infants and help prevent or minimize the risk of infection. One such strategy is the early introduction of enteral feedings designed to stimulate or prime the gut. Early introduction of enteral feedings in the acutely ill preterm infant appears to be well tolerated in a variety of small clinical studies. Although the studies vary considerably in design and variables measured, collectively they show a solid trend toward improved outcomes. By preventing the negative consequences of a prolonged period of NPO, early enteral feedings promote the normal processes of the gut as a physical, mechanical, physiologic, and immunologic barrier. A solid understanding of the pathophysiology of prolonged NPO status and the physiology of the gut's immune properties enables critical care nurses to improve care of these vulnerable NICU patients.

Glutamine supplementation and deprivation: effect on artificially reared rat small intestinal morphology

The mechanisms of how glutamine benefits critically ill patients have not been established. The purpose of this study was to determine the effects of dietary and endogenously produced glutamine on small intestinal morphology using light and transmission electron microscopy in artificially reared rat pups. It was hypothesized that deprivation of dietary glutamine leads to intestinal disease that is exacerbated by inhibition of glutamine synthetase by methionine sulfoximine (MS). Rat pups were placed into five different test groups: The first was a reference group that was reared by their mother. The other four groups were reared artificially and received a 10% Travasol amino acid solution at 5 g/kg per day, which does not contain glutamine, added to a mixture containing carbohydrates, lipids, and vitamins. This dose was chosen because it represents an approximation of the amount of glutamine these rats would be receiving in a normal rat diet (approximately 40 g/kg per day total protein, 10 to 15% of which is glutamine + glutamate). The glutamine was manipulated by adding glutamine (Q) or MS or both. The four groups were as follows: MS-Q-, MS-Q+, MS+Q-, and MS+Q+. Light microscopy revealed the greatest blunting of villus height in the ileum of rats from the MS+Q- group when compared with the MS-Q+ group (123 +/- 48.9 micro m versus 207 +/- 36 microm, p < 0.05). The other two groups exhibited intermediate villus heights, but all were shorter than the villi from the mother-reared animals. The number of villi per unit length of bowel was also lowest in the animals that were treated with MS and not provided with dietary glutamine. Transmission electron microscopy demonstrated breakdown of the epithelial junctions in the glutamine-deprived and glutamine synthetase-inhibited intestines. Glutamine-deprived animals also displayed sloughing of microvilli, decreased actin cores, and degeneration of the terminal web. In summary, these studies support the hypothesis that glutamine is involved with maintenance of intestinal epithelial integrity.

Glutamine in pediatrics: where next?

OBJECTIVE

We reviewed the literature and examined the issues surrounding the use of glutamine in pediatrics and neonatology.

METHODS

We reviewed the literature using Medline, Embase, Current Contents, and International Pharmaceutical Abstracts. Additional information was obtained from bibliographic citations and personal communications.

RESULTS

Evidence showed that glutamine levels are affected in a number of life stages and conditions. Useful, indicative studies are emerging but many fail to demonstrate significant differences. The problems of researching in this patient population were demonstrated.

CONCLUSION

A need for a great deal of further research in this area, including larger multicenter trials, clearly emerged.

Update on host defense and immunonutrients

Neonatal intensive care in the past three decades has provided exciting modalities for improving the survival of critically ill neonates. There remains a great need for improving the quality of life for these survivors. In this article, the role the developing GI tract and its microenvironment play in the well-being of the neonate has been emphasized. Future therapies based on manipulation of the GI tract and its microenvironment by functional foods, immunonutrients, or pharmacologic agents may have effects not only during the neonatal period, but also throughout the individual's entire life.

Glutamine promotes triglyceride absorption in a dose-dependent manner

Dietary proteins may play a role in lipid absorption. Whether amino acids are specifically involved is unknown. We hypothesized that enterally administered L-glutamine (L-Gln) given with a lipid meal increases triglyceride (TG) absorption in rats. Mesenteric lymph fistulae and gastroduodenal feeding tubes were placed in adult male Sprague-Dawley rats. The animals received an enteral bolus of Intralipid (5 ml) followed by enteral infusion of increasing concentrations of L-Gln in saline (0, 85, 170, or 340 mM) or equimolar concentrations of the inactive isomer D-Gln or an essential amino acid mixture without Gln. Lymph was collected continuously for 6 h and analyzed for TG content. Animals infused with 85 mM L-Gln had a 64% increase in total TG output vs. controls (P < 0.05) despite no difference in lymph flow rate. Total TG output for animals infused with 340 mM L-Gln declined by 43% vs. controls (P < 0.05). The effect of Gln in promoting lymphatic fat transport is specific to L-Gln and not shared by D-Gln or an equivalent amino acid mixture. L-Gln is capable of either promoting or impairing lymphatic TG transport in a dose-dependent manner.

Glutamine supplementation. Heal the gut, help the patient

Glutamine is the most abundant amino acid in the body. It is also one of the most widely researched amino acids, with multiple clinical trials on various aspects of medical nutritional care including gastrointestinal disease, oncology, burn-trauma, HIV/AIDS, and chronic wound management. Glutamine often is used as a singular nutrient supplement in both hospital and home settings. The goal of this article is to review patient applications and supportive literature, and to provide the reader with guidelines for daily use of glutamine as an oral or enteral supplement.

Glutamine supplementation in cancer patients receiving bone marrow transplantation and high dose chemotherapy

Glutamine supplementation of enteral and parenteral nutrition support has received increased attention in the research community over the past decade. Glutamine may become a conditionally essential nutrient during certain catabolic states, including after bone marrow transplantation (BMT). The administration of enteral or parenteral glutamine seems safe and also potentially efficacious in some patient groups undergoing intensive treatment for cancer. Studies indicate that adjunctive glutamine treatment may improve nitrogen retention, decrease clinical infection and length of hospital stay and reduce the incidence and severity of mucositis after BMT and high dose chemotherapy. Although not all studies demonstrate benefit, there are sufficient positive data to suggest that this nutrient should be considered in the metabolic support of many individuals undergoing the catabolic process of marrow transplantation. Given the available data, randomized, double-blind, controlled clinical trials of glutamine-enriched nutrition in patients receiving BMT and high dose chemotherapy protocols are indicated to further define the utility of this amino acid as adjunctive therapy. Studies of glutamine nutrition combined with current combinations of cytoreductive agents and hematopoietic growth factors in BMT will be particularly pertinent.

Glutamine in the fetus and critically ill low birth weight neonate: metabolism and mechanism of action

Of all the amino acids, glutamine is the most versatile. Studies in the maternal-fetal-placental unit demonstrate that both glutamine and glutamate play an important role in fetal and placental metabolism. If an infant is born very prematurely, the supply of glutamine from the mother is suddenly interrupted. The infant is dependent on endogenous synthesis or an exogenous supply of glutamine to meet the challenges of the external environment and a tripling of body weight in the first 3-4 mo of life. Studies of glutamine supplementation in low birth weight infants and critically ill adults suggest benefits, especially in terms of decreased nosocomial infections. Two large multicenter trials are currently underway that are designed to address these potential benefits in very low birth weight infants. These trials will not explain the mechanism of action. This review raises hypotheses about the role of the amide nitrogen of glutamine for nucleotide and glucosamine synthesis in the small intestine and how this might relate to greater integrity of the intestinal mucosa, hence preventing bacterial translocation and/or the subsequent proinflammatory response that might lead to multiorgan failure.

Reduced serum amino acid concentrations in infants with necrotizing enterocolitis

OBJECTIVE

To determine whether premature infants who have necrotizing enterocolitis (NEC) have deficiencies in glutamine (GLN) and arginine (ARG), which are essential to intestinal integrity.

STUDY DESIGN

A 4-month prospective cohort study of serum amino acid and urea levels in premature infants was done. Serum amino acid and urea levels were measured by high-pressure liquid chromatography and enzymatic methods, respectively, on samples obtained on days of life 3, 7, 14, and 21.

RESULTS

Infants in the control (n = 32) and NEC groups (n = 13) were comparable for birth weight, gestational age, and Apgar scores. NEC began on mean day of life 14.5 (95% CI, day of life 11 to 18). Median values of GLN were 37% to 57% lower in the NEC group on days 7, 14, and 21 compared with those in the control group (P <.05). On days 7 and 14, median values of ARG, GLN, alanine, lysine, ornithine, and threonine were decreased 36% to 67% (P <.05) in the NEC group. Total nonessential amino and total essential amino acids were 35% to 50% lower in the NEC group on days 7 and 14 (P <.05). Infants in the NEC group had significant reductions in GLN and ARG 7 days before the onset of NEC.

CONCLUSIONS

Infants who have NEC have selective amino acid deficiencies including reduced levels of GLN and ARG that may predispose to the illness.

Glutamine and the gastrointestinal tract

The amino acid glutamine has become one of the most intensively studied nutrients in the field of nutrition and metabolic support. A variety of studies in cell culture systems, animal models of gut mucosal atrophy, injury/repair and adaptation and a limited number of clinical trials demonstrate trophic and cytoprotective effects of glutamine in small bowel and colonic mucosal cells. Although the routine clinical use of glutamine-enriched parenteral and enteral nutrient solutions remains controversial, available data demonstrate both the safety and metabolic and clinical efficacy of glutamine treatment in selected patient groups. Basic investigations are elucidating underlying mechanisms of glutamine action in intestinal cells. These will inform preclinical and clinical investigations designed to determine glutamine efficacy in selected gastrointestinal disorders. Emerging clinical trials will further define the utility of adjunctive glutamine supplementation as a component of specialized nutrition support in gastrointestinal disease.

Glutamine supplementation in low-birth-weight infants: mechanisms of action

Very low-birth-weight infants have minimal endogenous nutritional reserves and are at high risk for stresses that induce further breakdown of these diminished reserves. They frequently receive very little glutamine because enteral feedings are often delayed and glutamine is not included in parenteral nutrition. Here we describe studies of glutamine supplementation in very low-birth-weight infants and discuss potential mechanisms for the beneficial effects.