Targeting optimal protein delivery in parenteral and enteral nutrition for preterm infants: a review of randomized, controlled trials

Close attention to nutritional management is essential for optimizing growth and neurodevelopment of the preterm infant. Protein intake and the protein to energy ratio are the main determinants of growth and body composition. Yet large, multi-center, randomized controlled trials are lacking to guide protein delivery for the preterm infant. Until these studies are pursued, smaller trials must be used to inform clinical practice. This review summarizes the randomized controlled trials that have been performed to test the impact of higher vs. lower protein delivery to the preterm infant. We consider the trials that varied protein delivery rates during parenteral and enteral phases of nutrition. Considerable heterogeneity exists across study designs. Still, cumulative evidence from these trials provides a framework for current recommendations for protein intake in the preterm infant.

Administering Parenteral Nutrition in the Neonatal Intensive Care Unit: Logistics, Existing Challenges, and a Few Conundrums

Use of parenteral nutrition (PN) in the neonatal intensive care unit (NICU) requires evaluating the need for central venous catheters, potential drug incompatibilities, unintentional exposures, and suboptimal energy and nutrient intake during the transition to full enteral nutrition. Risks of photooxidation reactions in PN components, refeeding syndrome, and excess early amino acid intake should prompt the reevaluation of routine practices. The goal of this paper is to review the practicalities, challenges, and conundrums of administering PN in the NICU.

Guidelines for parenteral nutrition in preterm infants: The American Society for Parenteral and Enteral Nutrition

BACKGROUND

Parenteral nutrition (PN) is prescribed for preterm infants until nutrition needs are met via the enteral route, but unanswered questions remain regarding PN best practices in this population.

METHODS

An interdisciplinary committee was assembled to answer 12 questions concerning the provision of PN to preterm infants. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) process was used. Questions addressed parenteral macronutrient doses, lipid injectable emulsion (ILE) composition, and clinically relevant outcomes, including PNALD, early childhood growth, and neurodevelopment. Preterm infants with congenital gastrointestinal disorders or infants already diagnosed with necrotizing enterocolitis or PN-associated liver disease (PNALD) at study entry were excluded.

RESULTS

The committee reviewed 2460 citations published between 2001 and 2023 and evaluated 57 clinical trials. For most questions, quality of evidence was very low. Most analyses yielded no significant differences between comparison groups. A multicomponent oil ILE was associated with a reduction in stage 3 or higher retinopathy of prematurity (ROP) compared to an ILE containing 100% soybean oil. For all other questions, expert opinion was provided.

CONCLUSION

Most clinical outcomes were not significantly different between comparison groups when evaluating timing of PN initiation, amino acid dose, and ILE composition. Future clinical trials should standardize outcome definitions to permit statistical conflation of data, thereby permitting more evidence based recommendations in future guidelines. This guideline has been approved by the ASPEN 2022-2023 Board of Directors.

The Role of Work as a Social Determinant of Health in Mother's Own Milk Feeding Decisions for Preterm Infants: A State of the Science Review

In the United States, 10% of infants are born preterm (PT; <37 weeks gestational age) each year and are at higher risk of complications compared to full term infants. The burden of PT birth is borne disproportionately by Black versus non-Black families, with Black mothers significantly more likely to give birth to a PT infant. One proven strategy to improve short- and long-term health outcomes in PT infants is to feed mother's own milk (MOM; breast milk from the mother). However, mothers must make decisions about work and MOM provision following PT birth, and more time spent in paid work may reduce time spent in unpaid activities, including MOM provision. Non-Black PT infants are substantially more likely than Black PT infants to receive MOM during the birth hospitalization, and this disparity is likely to be influenced by the complex decisions mothers of PT infants make about allocating their time between paid and unpaid work. Work is a social determinant of health that provides a source of income and health insurance coverage, and at the same time, has been shown to create disparities through poorer job quality, lower earnings, and more precarious employment in racial and ethnic minority populations. However, little is known about the relationship between work and disparities in MOM provision by mothers of PT infants. This State of the Science review synthesizes the literature on paid and unpaid work and MOM provision, including: (1) the complex decisions that mothers of PT infants make about returning to work, (2) racial and ethnic disparities in paid and unpaid workloads of mothers, and (3) the relationship between components of job quality and duration of MOM provision. Important gaps in the literature and opportunities for future research are summarized, including the generalizability of findings to other countries.

Preterm infant nutrition: considerations for infants at risk of refeeding syndrome

Refeeding syndrome (RS) in preterm infants is a scenario of fetal malnutrition, primarily resulting from placental insufficiency, followed by a postnatal physiologic adaptation and response to an imbalance of nutrients provided parenterally. Growth restriction and small gestational age status are common findings in infants at risk of developing RS. Adverse clinical outcomes associated with RS may be severe and life-threatening. The biochemical abnormalities that occur in RS may be mitigated through careful monitoring and adaptation of the clinical management of parenteral and enteral nutrition. This perspective reviews the physiology and metabolism in infants with RS and provides suggested approaches to their clinical monitoring and nutritional management.

Early Growth and Cognitive Development in Children Born Preterm: Relevance of Maternal Body Mass Index

OBJECTIVE

Maternal prepregnancy body mass index (BMI) represents a surrogate marker of fetal exposures to the maternal metabolism during pregnancy. Yet, it remains poorly understood whether this marker indicates risk of altered trajectories in postnatal growth and development in children born preterm. This study aimed to determine whether maternal prepregnancy BMI is associated with altered growth and development in children born preterm.

STUDY DESIGN

A retrospective cohort study evaluated prepregnancy BMI as the exposure for childhood outcomes using linear regression and mixed effects models. The 38 children included in this follow-up evaluation originally participated in a prospective, observational cohort study to determine longitudinal levels of lipid species in preterm human milk expressed by women who delivered prior to 32 weeks. Childhood outcomes in this study were anthropometric measures during hospitalization (n = 38), after discharge through 36 months (n = 34) and Bayley-III developmental scores through 18 months corrected age (n = 26).

RESULTS

In 38 children born prior to 32 weeks, higher maternal prepregnancy BMI was independently associated with higher preterm infant growth velocity during hospitalization, but not associated with in-hospital change in length or head circumference and/or postdischarge growth. In univariate linear regression models, higher maternal BMI was associated with lower cognitive scores at 18 months corrected age. This significant association remained in an adjusted model accounting for relevant influences on early childhood development.

CONCLUSION

Increasing maternal prepregnancy BMI may reflect risk of altered growth and cognitive development in children born preterm.

KEY POINTS

· Maternal BMI was associated with early preterm infant weight gain.. · Maternal BMI was not associated with postdischarge growth.. · Increased maternal BMI may be associated with lower cognitive function scores in offspring..

Hypertriglyceridemia in Preterm Infants

Preterm and critically ill infants are at risk for hypertriglyceridemia (HTG). Common risk factors for HTG include prematurity, intravenous lipid emulsion dose and oil composition, reduced lipoprotein lipase activity, fetal growth restriction, sepsis, and renal failure. Despite these risk factors, clinicians lack a universally agreed upon definition for HTG and evidence-based approach to HTG management. This review provides a detailed overview of triglyceride and intravenous lipid emulsion metabolism and how this relates to specific HTG risk factors, along with some practical considerations for managing HTG in the neonatal population.

Providing Breastfeeding Support During COVID-19: A Survey of Staff Experiences

BACKGROUND

The COVID-19 pandemic presents unique challenges to maternity settings. Its influence on providing in-hospital lactation support has not been well described.

RESEARCH AIM

To describe the experiences of healthcare workers as they provided in-hospital lactation support during the pandemic.

METHODS

A prospective, cross-sectional, online survey evaluated healthcare providers working with postpartum women and newborns affected by COVID-19 at an academic center during March-June 2020. Providers were queried regarding the influence of COVID-19 and COVID-19-specific policies on providing lactation support. Questions assessed guidance received, perceived stress, difficulty providing care, and solicited qualitative responses. The constant comparative method was used to analyze qualitative data.

RESULTS

Of 108 providers, 70 (65%) completed the survey. Of 57 providing direct lactation support to women affected by COVID-19, most (n = 39, 67%) reported increased stress. Participants reported lower stress scores when receiving guidance through shift meetings or email compared to those not receiving this guidance [stress score with shift meeting guidance (M [SD]): 3.10 (0.88); score without guidance: 3.83 (0.66); n = 39, p = .009; score with email guidance: 3.79 (0.58); score without guidance: 4.50 (0.58); n = 18, p = .045). Qualitative responses (n = 67; 96%) identified three themes: visitor restrictions allowed less distraction during lactation support; physical separation disrupted maternal/infant bonding; workflow challenges resulted from policy changes and supply access.

CONCLUSIONS

Most participating staff providing lactation support to participants affected by COVID-19 reported increased stress. Ensuring written or verbal guidance may reduce staff's experiences of stress. Efforts to optimize lactation support during COVID-19 should consider reducing distractions, physical separation, and logistic challenges.

Recommendations for photoprotection of parenteral nutrition for premature infants: An ASPEN position paper

Although crucial in improving health outcomes in the preterm infants, parenteral nutrition (PN) is not without risk, especially if handled improperly. A growing body of evidence suggests that components of PN admixtures, including lipid injectable emulsions (ILEs), are susceptible to degradation, including oxidation when exposed to light (ie, photo-oxidation), resulting in the production of reactive oxygen species. Infants, especially those born preterm, are considered more susceptible to consequences of oxidative stress than children and adults. Oxidative stress is associated with bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and intestinal failure-associated liver disease. The American Society for Parenteral and Enteral Nutrition (ASPEN) assembled a working group to provide recommendations on clinical practice surrounding photoprotection of PN.This Position Paper reviews the scientific literature on the formation of quantifiable peroxides and other degradation products when PN admixtures and ILEs are exposed to light and reports adverse clinical outcomes in premature infants exposed to PN. Recommendations for photoprotection of PN admixtures and ILEs are provided, as well as the challenges in achieving complete photoprotection with the equipment, supplies, and materials currently available in the US. ASPEN and the authors understand that the full implementation of complete photoprotection may not currently be feasible given current product availability; recommendations provided in this paper serve to represent the goal to which to strive as well as to highlight the importance of product availability to achieve these practices. This paper has been approved by the ASPEN Board of Directors.

Dietary Fat and Fatty Acid Intake in Nulliparous Women: Associations with Preterm Birth and Distinctions by Maternal BMI

BACKGROUND

Evidence documenting whether diet quality, particularly dietary fatty acids, is associated with preterm birth (PTB) is limited.

OBJECTIVE

The aim was to measure associations between dietary fatty acid intake prior to pregnancy, specifically n-3 (ɷ-3) PUFAs and odds of PTB in US women and determine if associations differed by prepregnancy BMI.

METHODS

We designed a secondary analysis of dietary intake in nulliparous women enrolled in a longitudinal cohort (NCT01322529). Participants completed an FFQ, modified to assess detailed PUFA intake, during the 3 mo preceding pregnancy. Inclusion in this analytic cohort required total energy intake within 2 SDs of the group mean. Prepregnancy BMI was categorized as underweight, normal, overweight, or obese. The primary exposure was estimated intake of EPA and DHA (combined EPA+DHA), in the context of a recommended intake of 250 mg. The primary outcome was PTB (<37 wk). Adjusted regression models controlled for maternal factors relevant to PTB and evaluated associations with PUFAs. Interaction terms estimated effect modification of BMI. A false discovery rate (FDR) correction accounted for multiple comparisons.

RESULTS

Median daily intake of combined EPA+DHA in 7365 women was 70 mg (IQR: 32, 145 mg). A significant interaction term indicated the effects of EPA+DHA on odds of PTB were different for different BMI categories (P < 0.01). Specifically, higher intake of combined EPA+DHA was nominally associated with reduced odds of PTB in women with underweight (OR: 0.67; 95% CI: 0.46-0.98) and normal BMI (OR: 0.87; 95% CI: 0.78-0.96), yet was associated with increased odds of overweight BMI (OR: 1.21; 95% CI: 1.02-1.44). Associations remained significant after FDR correction.

CONCLUSIONS

Based on a cohort of US women designed to identify predictors of adverse pregnancy outcomes, dietary intake of combined EPA+DHA was considerably lower than recommended. Associations between intake of these recommended n-3 fatty acids and risk of PTB differ by maternal BMI.

Randomized Controlled Trial of Early Docosahexaenoic Acid and Arachidonic Acid Enteral Supplementation in Very Low Birth Weight Infants

OBJECTIVE

To determine feasibility of providing a concentrated emulsified long-chain polyunsaturated fatty acids (LCPUFA) supplement to very low birth weight infants, and to evaluate blood LCPUFA concentrations at 2 and 8 weeks of study supplementation.

STUDY DESIGN

This prospective, randomized, double-blind, placebo-controlled trial randomized infants to receive (1) LCPUFA-120 (a supplement of 40 mg/kg/day docosahexaenoic acid [DHA] and 80 mg/kg/day arachidonic acid [ARA]; DHA:ARA at 1:2 ratio), (2) LCPUFA-360 (a supplement of 120 mg/kg/day DHA and 240 mg/kg/day ARA), or (3) sunflower oil (placebo control). Infants received supplement daily for 8 weeks or until discharge, whichever came first. Whole blood LCPUFA levels (wt%; g/100 g) were measured at baseline, 2 weeks, and 8 weeks.

RESULTS

Infants were 28 weeks of gestation (IQR, 27-30 weeks of gestation) and weighed 1040 g (IQR, 910-1245 g). At 2 weeks, the change in blood DHA (wt%) from baseline differed significantly among groups (sunflower oil, n = 6; -0.63 [IQR, -0.96 to -0.55]; LCPUFA-120: n = 12; -0.14 [IQR, -0.72 to -0.26]; LCPUFA-360, n = 12; 0.46 [IQR, 0.17-0.81]; P = .002 across groups). Change in blood ARA (wt%) also differed by group (sunflower oil: -2.2 [IQR, -3.9 to -1.7]; LCPUFA-120: 0.1 [IQR, -2.1 to 1.1] vs LCPUFA-360: 2.9 IQR, 1.5 to 4.5]; P = .0002). Change from baseline to 8 weeks significantly differed between groups for DHA (P = .02) and ARA (P = .003).

CONCLUSIONS

Enteral LCPUFA supplementation supported higher blood DHA by 2 weeks. LCPUFA supplementation at 360 mg of combined DHA and ARA is likely necessary to reduce declines as well as allow increases in whole blood concentrations in the first 8 weeks of life.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03192839.

Intravenous Lipid Emulsions in the NICU

The clinical goals of intravenous lipid emulsions (ILEs) have changed since their initial development. In the past, 100% soybean oil was used to provide energy and prevent an essential fatty acid deficiency. Now, different oil sources are used with the goal of improving nutritional status and preventing common neonatal comorbidities. We now have a better understanding of specific ILE constituents, namely, fatty acids, vitamin E, and phytosterols, and how these components contribute to complications such as intestinal failure-associated liver disease. This review addresses the development and composition of different ILEs and summarizes how individual ILE ingredients affect infant metabolism and health.

Low prevalence of clinical decision support to calculate caloric and fluid intake for infants in the neonatal intensive care unit

BACKGROUND

Clinical decision support (CDS) improves nutrition delivery for infants in the neonatal intensive care unit (NICU), however, the prevalence of CDS to support nutrition is unknown.

METHODS

Online surveys, with telephone and email validation of responses, were administered to NICU clinicians in the Children's Hospital Neonatal Consortium (CHNC). We determined and compared the availability of CDS to calculate calories and fluid received in the prior 24 h, stratified by enteral and parenteral intake, using McNemar's test.

RESULTS

Clinicians at all 34 CHNC hospitals responded with 98 of 108 (91%) surveys completed. NICUs have considerably less CDS to calculate enteral calories received than enteral fluid received (32% vs. 82%, p < 0.001) and less CDS to calculate parenteral calories received than parenteral fluid received (29% vs. 82%, p < 0.001).

DISCUSSION

Most CHNC NICUs are unable to reliably and consistently monitor caloric intake delivered to critically ill infants at risk for growth failure.

Energy and Protein Intake During the Transition from Parenteral to Enteral Nutrition in Infants of Very Low Birth Weight

OBJECTIVE

To evaluate the association between nutrition delivery practices and energy and protein intake during the transition from parenteral to enteral nutrition in infants of very low birth weight (VLBW).

STUDY DESIGN

This was a retrospective analysis of 115 infants who were VLBW from a regional neonatal intensive care unit. Changes in energy and protein intake were estimated during transition phase 1 (0% enteral); phase 2 (>0, ≤33.3% enteral); phase 3 (>33.3, ≤66.7% enteral); phase 4 (>66.7, <100% enteral); and phase 5 (100% enteral). Associations between energy and protein intake were determined for each phase for parenteral nutrition, intravenous lipids, central line, feeding fortification, fluid restriction, and excess non-nutritive fluid intake.

RESULTS

In phases 2 and 3, infants receiving feeding fortification received less protein than infants who were unfortified (-1.1 and -0.3 g/kg/d, respectively; P < .001). However, this negative association was not observed after adjusting for relevant nutrition delivery practices. Despite greater enteral protein intake during phases 2 and 3 (0.3 and 0.8 g/kg/d, respectively; P < .001), infants with early fortification received less parenteral protein than infants who were unfortified (-1.4 and -1.1 g/kg/d, respectively; P < .001). Similar patterns were observed for energy intake. Protein intake declined during phases 3 and 4.

CONCLUSIONS

Infants paradoxically received less protein and energy on days with early fortification, suggesting that clinicians may lack easily accessible data to detect the association between nutrition delivery practices and overall nutrition in infants who are VLBW.

Do I focus on the process of cycling or try to put my mind elsewhere? A comparison of concentration strategies for use in pacing by novice riders

The ability to hold a pace is a key skill for endurance athletes. The present study compared the influence of different strategies on how athletes learn to pace at 80% of their maximum performance for a 3-min cycle time trial. Participants first completed three maximal 3-min tests to establish maximal performance. During subsequent visits we asked participants to ride at 80% of their average maximal 3-min power output for four 3-min efforts under different conditions. Participants were blinded to feedback for three of the four conditions with participants (a) riding on feel (all feedback blinded), (b) associating on the task by focusing attention on the skills needed for efficient cycling, and (c) dissociating from the task by intentionally focusing concentration elsewhere (d) and finally, participants rode with full feedback where pace could be regulated via observation. All participants completed the blind condition first, the full feedback condition last, with association focus and dissociation focus rides being alternated. As expected, results showed participants rode close to the 80% goal when observing full feedback. Participants rode at 82% of maximum in the blind "ride on feel" condition, 79% in the associative condition, and 70% in the dissociative condition. We suggest results show that simple strategies related to concentration can influence the accuracy of pacing efforts. The difference in the ability to pace while using an associative or dissociative attentional focus was consistent with theory. The differences we observed occurred with minimal input from participants in terms of actively learning psychological skills. Future research is needed to investigate how athletes learn to use pacing strategies to help performance.

Donor milk intake and infant growth in a South African neonatal unit: a cohort study

Background

Implications of donor milk feedings on infant growth in resource limited settings remain uncertain. This knowledge gap includes the impact of donor milk availability on infant intake of mother’s own milk. Therefore, this investigation aimed to measure intake and growth in infants receiving donor milk when born to women from resource limited backgrounds with high rates of human immunodeficiency virus (HIV).

Methods

A retrospective cohort study enrolled eligible infants admitted to a South African combined neonatal intensive and secondary high care unit, within a one year admission period during 2015, with signed consent for donor milk feedings. A certified milk bank provided donor milk. Daily nutritional intake during the first month was recorded. Details included proportional intake of donor milk, mother’s own milk and infant formula. The primary outcome of infant growth velocity from day back to birth weight to discharge was calculated when length of stay was ≥14 days. Analyses primarily used T-tests; mixed effects models compared weekly calorie intake.

Results

One hundred five infants with donor milk consent were born at 30.9 ± 3.6 weeks of gestation, weighing 1389 ± 708 g. Forty percent of mothers had HIV. Infant growth velocity did not differ based on percent of feedings as donor milk (≥ 50%: 11.8 ± 4.9 g/kg/d; < 50%: 13.5 ± 5.3 g/kg/d; p = 0.3). Percent of feedings from donor milk was similar based on maternal HIV status (positive: 31 ± 25%; negative: 36 ± 29%; p = 0.4), as was percent of feedings as mother’s milk (positive: 53 ± 35%; negative: 58 ± 30%; p = 0.4). Calorie intake increased markedly during the first two weeks and then plateaued (p < 0.0001).

Conclusions

Donor milk feedings in higher proportions did not further impair growth of infants managed in a South African combined neonatal intensive and secondary high care unit with growth rates already below reference ranges. The provision of donor milk contributed to feedings being composed of primarily human milk during the first month. Increasing early calorie intake may improve infant growth in this center.

Two-Year Neurodevelopment and Growth Outcomes for Preterm Neonates Who Received Low-Dose Intravenous Soybean Oil

BACKGROUND

In some studies, the dose of intravenous soybean oil (SO) has been associated with a decreased incidence of intestinal failure-associated liver disease. The effect of lipid sparing on neurodevelopment (ND) and growth remains unknown. This study investigated the impact of SO dose on ND and growth over the first 2 years of age in preterm neonates.

MATERIALS AND METHODS

This is a single-site prospective follow-up study. Neonates with a gestational age ≤29 weeks were randomized to low-dose (LOW) or standard-dose (CON) SO. Bayley Scales of Infant Development III and anthropometric measurements were collected at approximately 6, 12, and 24 months corrected gestational age.

RESULTS

Subjects were premature, with a mean (±SD) gestational age of 28 ± 1 and 27 ± 1 weeks (P = .3) for LOW and CON, respectively. Thirty subjects completed follow-up (LOW = 15, CON = 15). There were no differences for ND and growth outcomes when LOW was compared with CON, with the exception of a higher 12-month follow-up cognitive scaled score in the LOW group (P = .02).

CONCLUSION

A reduced SO dose did not adversely affect ND or growth in this cohort of preterm neonates. However, larger studies are needed to determine the long-term safety of SO dose reduction before this strategy can be adopted.

Association Between the 7-Day Moving Average for Nutrition and Growth in Very Low Birth Weight Infants

BACKGROUND

Very low birth weight (VLBW) infants remain at risk for postnatal growth restriction. Clinicians may have difficulty identifying growth patterns resulting from nutrition interventions, impeding prompt management changes intended to increase growth velocity. This study aimed to quantify the association between growth and nutrition intake through 7-day moving averages (SDMAs).

METHODS

The first 6 weeks of daily nutrition intake and growth measurements were collected from VLBW infants admitted to a level 4 neonatal intensive care unit (2011-2014). The association between SDMA for energy and macronutrients and subsequent 7-day growth velocities for weight, length, and head circumference were determined using mixed effects linear regression. Analyses were adjusted for fluid intake, infant characteristics, and comorbid conditions.

RESULTS

Detailed enteral and parenteral caloric provisions were ascertained for 115 infants (n = 4643 patient-days). Each 10-kcal/kg/d increase over 7 days was independently associated with increased weight (1.7 g/kg/d), length (0.4 mm/wk), and head circumference (0.9 mm/wk; P < .001, for weight and head circumference; P = .041 for length). Each 1 g/kg/d macronutrient increase was also associated with increased weight (protein, P = .027; fat and carbohydrates, P < .001), increased length (fat, P = .032), and increased head circumference (fat and carbohydrates, P < .001).

CONCLUSIONS

The SDMA identifies clinically meaningful associations among total energy, macronutrient dosing, and growth in VLBW infants. Whether SDMA is a clinically useful tool for providing clinicians with prompt feedback to improve growth warrants further attention.

Long chain fatty acids and related pro-inflammatory, specialized pro-resolving lipid mediators and their intermediates in preterm human milk during the first month of lactation

This study aimed to measure longitudinal quantities of the long chain fatty acids, their biologically active terminal metabolites and related intermediates (also called oxylipins) in preterm human milk expressed during the first month of lactation. In a prospective cohort, breast milk was collected throughout the first month of lactation in 30 women who delivered preterm infants. Eighteen bioactive lipids and their intermediates were quantified via solid phase extraction and LC-MS/MS. Analysis by GC-FID quantified the fatty acid precursors. Arachidonic acid (ARA) and docosahexaenoic acid (DHA) milk concentrations significantly declined throughout the first month. Oxylipin concentrations did not change during lactation. Positive associations existed between ARA and thromboxane B2, eicosapentaenoic acid and 18-hydroxyeicosapentaenoic acid, and between DHA and PDX and 14- and 17-hydroxydocosahexaenoic acids. DHA concentrations were 1.5 times higher and 14-HDHA was 1.7 times higher in milk from women taking DHA supplements. This investigation showed conditionally essential fatty acids, ARA and DHA, decreased in preterm milk, suggesting a need to supplement their intake for the breast milk-fed preterm infant. Positive associations between parent fatty acids, bioactive lipids and intermediates, as well as sensitivity of milk to maternal fatty acid intake, support consideration of a comprehensive approach to providing fatty acids for preterm infants through both maternal and infant supplementation.

When Is Parenteral Nutrition Appropriate?

Parenteral nutrition (PN) represents one of the most notable achievements of modern medicine, serving as a therapeutic modality for all age groups across the healthcare continuum. PN offers a life-sustaining option when intestinal failure prevents adequate oral or enteral nutrition. However, providing nutrients by vein is an expensive form of nutrition support, and serious adverse events can occur. In an effort to provide clinical guidance regarding PN therapy, the Board of Directors of the American Society for Parenteral and Enteral Nutrition (ASPEN) convened a task force to develop consensus recommendations regarding appropriate PN use. The recommendations contained in this document aim to delineate appropriate PN use and promote clinical benefits while minimizing the risks associated with the therapy. These consensus recommendations build on previous ASPEN clinical guidelines and consensus recommendations for PN safety. They are intended to guide evidence-based decisions regarding appropriate PN use for organizations and individual professionals, including physicians, nurses, dietitians, pharmacists, and other clinicians involved in providing PN. They not only support decisions related to initiating and managing PN but also serve as a guide for developing quality monitoring tools for PN and for identifying areas for further research. Finally, the recommendations contained within the document are also designed to inform decisions made by additional stakeholders, such as policy makers and third-party payers, by providing current perspectives regarding the use of PN in a variety of healthcare settings.

Growth and Development in Extremely Low Birth Weight Infants After the Introduction of Exclusive Human Milk Feedings

Objective To estimate associations of exclusive human milk (EHM) feedings with growth and neurodevelopment through 18 months corrected age (CA) in extremely low birth weight (ELBW) infants. Study Design ELBW infants admitted from July 2011 to June 2013 who survived were reviewed. Infants managed from July 2011 to June 2012 were fed with bovine milk-based fortifiers and formula (BOV). Beginning in July 2012, initial feedings used a human milk-based fortifier to provide EHM feedings. Infants were grouped on the basis of feeding regimen. Primary outcomes were the Bayley-III cognitive scores at 6, 12, and 18 months and growth. Results Infants (n = 85; 46% received EHM) were born at 26 ± 1.9 weeks (p = 0.92 between groups) weighing 776 ± 139 g (p = 0.67 between groups). Cognitive domain scores were similar at 6 months (BOV: 96 ± 7; EHM: 95 ± 14; p = 0.70), 12 months (BOV: 97 ± 10; EHM: 98 ± 9; p = 0.86), and 18 months (BOV: 97 ± 16; EHM: 98 ± 14; p = 0.71) CA. Growth velocity prior to discharge (BOV: 12.1 ± 5.2 g/kg/day; EHM: 13.1 ± 4.0 g/kg/day; p = 0.33) and subsequent growth was similar between groups. Conclusion EHM feedings appear to support similar growth and neurodevelopment in ELBW infants as compared with feedings containing primarily bovine milk-based products.

Early-Life Exposure to Antibiotics, Alterations in the Intestinal Microbiome, and Risk of Metabolic Disease in Children and Adults

The intestinal microbiome is a complex ecosystem of microorganisms that colonize the human gastrointestinal tract. The microbiome evolves rapidly in early life with contributions from diet, genetics and immunomodulatory factors. Changes in composition of the microbiota due to antibiotics may lead to negative long-term effects including obesity and diabetes mellitus, as evidenced by both animal and large human studies. Inappropriate exposures to antibiotics occur frequently in early childhood. Therefore, an evidence-based system of antimicrobial use should be employed by all providers, especially those who care for pediatric patients. This article explores the natural evolution of the intestinal microbiome from the perinatal period into early childhood, the effect of antibiotics on the microbial ecology, and the implications for future health and disease.

Parenteral nutrition use and associated outcomes in a select cohort of low birth weight neonates

OBJECTIVE

The aim of this study is to assess the influence of parenteral nutrition (PN) on the time to regain birth weight in premature neonates born between 1,500 and 2,499 g.

STUDY DESIGN

A retrospective analysis stratified premature neonates born between 1,500 and 2,499 g by receipt of PN or intravenous dextrose at ≤ 72 hours of age. The primary outcome was the time to regain birth weight. Secondary measures included preterm-associated morbidities, time to achieve predefined enteral nutrition milestones, and length of stay. Multivariable regression estimated associations between PN and time to achieve nutrition milestones.

RESULTS

Among 260 eligible neonates, those receiving PN (53%) were less mature, weighed less at birth, had a higher index of illness severity, and higher prevalence of preterm-associated morbidities (p < 0.01). The time to regain birth weight (PN, 9.4 ± 3.5 d; no PN, 9.5 ± 3.4 d) was similar between groups. Regression analysis adjusting for gestational age, illness severity, and sepsis demonstrated that PN exposure was associated with a greater time to achieve nutrition milestones and length of stay (p < 0.05).

CONCLUSION

Although its impact on growth remains uncertain among premature neonates born between 1,500 and 2,499 g, PN was independently associated with a greater time to achieve nutrition milestones.

Low-Dose Intravenous Soybean Oil Emulsion for Prevention of Cholestasis in Preterm Neonates

BACKGROUND

Premature infants depend on intravenous fat emulsions to supply essential fatty acids and calories. The dose of soybean-based intravenous fat emulsions (S-IFE) has been associated with parenteral nutrition (PN)-associated liver disease. This study's purpose was to determine if low-dose S-IFE is a safe and effective preventive strategy for cholestasis in preterm neonates.

MATERIALS AND METHODS

This is a multicenter randomized controlled trial in infants with a gestational age (GA) ≤29 weeks. Patients <48 hours of life were randomized to receive a low (1 g/kg/d) or control dose (approximately 3 g/kg/d) of S-IFE. The primary outcome was cholestasis, defined as a direct bilirubin ≥15% of the total bilirubin at 28 days of life (DOL) or full enteral feeds, whichever was later, after 14 days of PN. Secondary outcomes included growth, length of hospital stay, death, and major neonatal morbidities.

RESULTS

In total, 136 neonates (67 and 69 in the low and control groups, respectively) were enrolled. Baseline characteristics were similar for the 2 groups. When the low group was compared with the control group, there was no difference in the primary outcome (69% vs 63%; 95% confidence interval, -0.1 to 0.22; P = .45). While the low group received less S-IFE and total calories over time compared with the control group (P < .001 and P = .03, respectively), weight, length, and head circumference at 28 DOL, discharge, and over time were not different (P > .2 for all).

CONCLUSION

Compared with the control dose, low-dose S-IFE was not associated with a reduction in cholestasis or growth.

From actors to agents in socio-ecological systems models

The ecosystem service concept has emphasized the role of people within socio-ecological systems (SESs). In this paper, we review and discuss alternative ways of representing people, their behaviour and decision-making processes in SES models using an agent-based modelling (ABM) approach. We also explore how ABM can be empirically grounded using information from social survey. The capacity for ABM to be generalized beyond case studies represents a crucial next step in modelling SESs, although this comes with considerable intellectual challenges. We propose the notion of human functional types, as an analogy of plant functional types, to support the expansion (scaling) of ABM to larger areas. The expansion of scope also implies the need to represent institutional agents in SES models in order to account for alternative governance structures and policy feedbacks. Further development in the coupling of human-environment systems would contribute considerably to better application and use of the ecosystem service concept.

Parenteral nutrition-associated cholestasis in small for gestational age infants

OBJECTIVE

To identify small for gestational age (SGA) as an independent risk factor for parenteral nutrition-associated cholestasis (PNAC).

STUDY DESIGN

In a case-control study, records of infants treated in the neonatal intensive care unit from 1994 through 2003 with gestational ages (GA) < 34 weeks and exposure to parenteral nutrition (PN) > or = 7 days were reviewed. The primary outcome was the incidence of cholestasis in infants who were SGA. Secondary outcomes included PN duration, age at full enteral nutrition (FEN) and incidence of late-onset sepsis, necrotizing enterocolitis (NEC) and bronchopulmonary dysplasia (BPD). Analysis was by t test, logistic regression, and chi2 analysis.

RESULTS

Cases (n = 79) and control subjects (n = 152) had similar birth weights and GA (963 +/- 465 g versus 1090 +/- 463 g; 27 +/- 2 weeks versus 27 +/- 2 weeks; [mean +/- SD]). Of the infants who were SGA, 58% developed cholestasis (OR = 3.3, P < .01). Infants with cholestasis achieved FEN later (43 +/- 25 days versus 23 +/- 11 days) and had higher rates of sepsis (80% versus 34%), NEC (51% versus 7%), and BPD (65% versus 25%; P < .01). Of infants with cholestasis, infants who were SGA received fewer days of PN than infants who were appropriate for GA (49 +/- 24 days versus 68 +/- 36 days, P = .024).

CONCLUSION

Being SGA is an independent risk factor for PNAC. Infants who are SGA require less PN for cholestasis to develop.

Interlaboratory comparison of the assessment of P450 activities in human hepatic microsomal samples

1. Although the importance of in vitro technology in supporting drug development is widely accepted, there is no real consensus about which approaches should be taken, which substrates should be used, or on the reliability and application of in vitro data. Consequently, as part of a collaborative project to characterize human liver with respect to the major forms of cytochrome P450, an interlaboratory comparison of the analysis of samples for form-specific activities was undertaken. 2. Microsomal fractions were isolated from five different human liver samples taken from the liver bank maintained at the Royal Postgraduate Medical School (RPMS). Aliquots from the five samples were sent to the 11 collaborating laboratories for characterization using their in-house, form-specific assays for cytochrome P450 activities. Although each laboratory assayed protein concentration, total cytochrome P450 content and enzyme activities were calculated using the protein estimation generated by RPMS to eliminate this possible source of variability. 3. With the exception of one laboratory, all estimates of protein concentration were similar (coefficient of variation, CoV, 9-13%) and the rank-order of the five samples was consistent across the laboratories. There was greater variability in the estimates of total cytochrome P450 content (CoV 28-43%), although again rank order of the samples across laboratories was fairly consistent. 4. The various laboratories used a number of different probe substrates, together with a range of conditions (substrate concentration, time of incubation, amount of protein), to assay for activity of CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4. However, apart from the occasional outlier, the five samples were ranked for activity of all these forms of cytochrome P450 with a high degree of consistency by the various laboratories and the choice of substrate had no appreciable effect on the ranking of the samples. 5. While this interlaboratory comparison has shown that greater consistency in the approach to in vivo determination of drug-metabolizing activity is desirable, there was little indication that any particular approach or substrate was superior to the others.

Adjustment of iron intake for dietary enhancers and inhibitors in population studies: bioavailable iron in rural and urban residing Russian women and children

Although determining iron intakes is essential in assessing adequacy of iron in the diet, estimating iron availability may be more useful for evaluating whether iron requirements are met. Our objectives were to describe the dietary information, analytical steps, and computer algorithms needed for iron bioavailability adjustments and to demonstrate the effects of various dietary factors on calculated iron absorption. Our study was based on 9890 women and children participating in the Russian Longitudinal Monitoring Survey. Between August 1992 and February 1993, two 24-h recalls were collected from each participant, and total, heme and nonheme iron intakes were calculated. Nonheme iron availability was adjusted for meat, fish and poultry and vitamin C consumed in the same meal and then further adjusted for tea and phytates. We found mean total iron intakes to be comparable to those of women of reproductive age in the United States and lower than those of United States children. When these intakes were adjusted for enhancers and inhibitors of absorption, the iron bioavailability in these vulnerable Russian groups was extremely low. Mean bioavailable iron as well as the 25th-75th percentile ranges of intake were below the bottom of the range of requirements, indicating that iron adequacy in this population may be considerably less than expected based on total iron intakes alone. Furthermore, rural and urban food availability had a significant effect on iron bioavailability. Future research on dietary iron adequacy should be based on estimates of available iron by collecting meal-level dietary data and using detailed information on mixed dishes and phytates.

A novel class of cyclic beta-dicarbonyl leaving groups and their use in the design of benzisothiazolone human leukocyte elastase inhibitors

Human leukocyte elastase (HLE) has been proposed to be a primary mediator of pulmonary emphysema, and inhibitors of this enzyme should be effective in the treatment of emphysema and other pulmonary diseases. We have discovered a novel class of alicyclic and heterocyclic leaving groups which share one common structural feature, a cyclic beta-dicarbonyl. This design concept for leaving groups has not been previously reported. A structure-activity relationship has been developed and the concept extended to several types of alicyclic and heterocyclic beta-dicarbonyl systems. This work led to the identification of a potent (K*i of 0.066 nM) and tissue stable (in vitro: blood t1/2 = 160 min, liver t1/2 > 240 min) benzisothiazolone HLE inhibitor, WIN 65936 (13b).

Picornavirus inhibitors: trifluoromethyl substitution provides a global protective effect against hepatic metabolism

Several modifications of the oxazoline ring of WIN 54954, a broad spectrum antipicornavirus compound, have been prepared in order to address the acid lability and metabolic instability of this compound. We have previously shown that the oxadiazole analogue 3 displayed comparable activity against a variety of rhinoviruses and appeared to be stable to acid. A monkey liver microsomal assay was developed to examine the metabolic stability in vitro of both compounds, and it was determined that WIN 54954 displayed 18 metabolic products while 3 was converted to 8 products. Two major products of 3 were determined by LC-MS/MS to be monohydroxylated at each of the terminal methyl groups. Replacement of the methyl on the isoxazole ring with a trifluoromethyl group, while preventing hydroxylation at this position, did not reduce the sensitivity of the molecule to microsomal metabolism at other sites. However, the (trifluoromethyl)oxadiazole 9 not only prevented hydroxylation at this position but also provided protection at the isoxazole end of the molecule, resulting in only two minor products to the extent of 4%. The major product was identified as the monohydroxylated compound 23. The global metabolic protective effect of trifluoromethyl group on the oxadiazole ring was further demonstrated by examining a variety of analogues including heterocyclic replacements of the isoxazole ring. In each case, the trifluoromethyl analogue displayed a protective effect when compared to the corresponding methyl analogue.

The bioavailability and metabolism of trilostane in normal subjects, a comparative study using high pressure liquid chromatographic and quantitative cytochemical assays

High pressure liquid chromatographic (HPLC) analysis of plasma taken over 8 h from ten normal male subjects medicated with 120 mg of trilostane revealed that the drug is rapidly metabolised into at least one metabolite, 17-keto trilostane. Both compounds were detected in the blood stream at concentrations greater than 2 X 10(-7) M within an hour and were cleared from the blood by 6-8 h. Approximately 3 times the concentration of metabolite was detected compared to the parent compound in most samples analysed. There were large subject to subject variations in the handling of drug. Standard curves of pure 17-keto trilostane and trilostane were parallel as assessed by cytochemical bioassay. This assay is based upon the inhibition of 3 beta-hydroxysteroid dehydrogenase activity in unfixed tissue sections of the dioestrous rat ovary. The relative potency of the metabolite compared to trilostane was 1.71 (95% confidence 1.5-2.0) over the dose range 0.15-1.5 microM. Thus, the metabolite may be the major active agent when trilostane is administered for clinical purposes. In a further 4 volunteers, who also received 120 mg trilostane and were sampled over an 8 h period, plasma was analysed independently by HPLC and cytochemical assays. In the majority of cases the bioactivity recorded (relative to a trilostane standard curve) was substantially higher than the molar sum of circulating trilostane and 17-keto-trilostane (as assessed by HPLC). However, if the relative potency of 17-keto-trilostane is taken into consideration, correlation between the two assays was excellent (r = 0.947, n = 18, P less than 0.001). This also suggests that no further active metabolites were present in the plasma samples. The drug profiles seen in the second study were essentially the same as described for the first 10 volunteers. The combination of a bioassay, which detects trilostane-like bioactivity, and HPLC, which reveals the type of metabolism, should aid our understanding of the clinical value of this potentially important drug.

Clinical and microbiological study of non-gonococcal urethritis with particular reference to non-chlamydial disease

A double-blind placebo-controlled study of minocycline in 221 men with non-gonococcal urethritis (NGU) was undertaken. Techniques were used which enabled diagnoses of chlamydial and mycoplasmal infections to be made within 24 hours of a patient attending a clinic. All patients from whom Chlamydia trachomatis was isolated were treated with minocycline, while patients from whom Ureaplasma urealyticum or Mycoplasma hominis was isolated, or from whom no micro-organisms were isolated, were treated on a double-blind basis with either minocycline or placebo. Chlamydia were isolated from 77 (35%) patients and were eradicated by minocycline from 76 (99%). Ureaplasmas were isolated initially from 96 (43%) patients. Treatment with minocycline eradicated them from 43 of 52 (83%) patients, and they disappeared from six of 31 (19%) patients who were treated with placebo. After one week significantly more patients had responded clinically to minocycline than to placebo. The response to minocycline was not influenced by the microbiological status of the patients, which suggests that ureaplasmas are playing a similar role to chlamydia in the pathogenesis of the disease and that an antibiotic-sensitive micro-organism may be producing disease in the isolate-negative group. An immunological approach is required to resolve the problem of the persistent urethral inflammation which occurred despite eradication of the micro-organisms.