Early nutrition and weight gain in preterm newborns and the risk of retinopathy of prematurity

Nutritional interventions to prevent retinopathy of prematurity

Very preterm infants are at high risk of growth failure. Poor weight gain is a prominent risk factor for retinopathy of prematurity (ROP) and optimizing nutrition could potentially promote growth and reduce ROP. Most infants at risk of ROP need parenteral nutrition initially and studies of enhanced parenteral provision of lipids and amino acids have suggested a beneficial effect on ROP. Higher amino acid intake was associated with lower incidence of hyperglycemia, a risk factor for ROP. For very preterm infants, providing unpasteurized fortified raw maternal breast milk appears to have a dose-dependent preventive effect on ROP. These infants become deficient in arachidonic acid (ArA) and docosahexaenoic acid (DHA) after birth when the maternal supply is lost. Earlier studies have investigated the impact of omega-3 fatty acids on ROP with mixed results. In a recent study, early enteral supplementation of ArA 100 mg/kg/d and DHA 50 mg/kg/d until term equivalent age reduced the incidence of severe ROP by 50%. IMPACT: Previous reviews of nutritional interventions to prevent morbidities in preterm infants have mainly addressed bronchopulmonary dysplasia, brain lesions and neurodevelopmental outcome. This review focusses on ROP. Neonatal enteral supplementation with arachidonic acid and docosahexaenoic acid, at levels similar to the fetal accretion rate, has been found to reduce severe ROP by 50% in randomized controlled trials.

Gut Microbiome and Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a leading cause of childhood blindness worldwide, is strongly associated with gestational age and weight at birth. Yet, many extremely preterm infants never develop ROP or develop only mild ROP with spontaneous regression. In addition, a myriad of other factors play a role in the retinal pathology, one of which may include the early gut microbiome. The complications associated with early gestational age include dysbiosis of the dynamic neonatal gut microbiome, as evidenced by the development of often concomitant conditions, such as necrotizing enterocolitis. Given this, alongside growing evidence for a gut-retina axis, there is an increasing interest in how the early intestinal environment may play a role in the pathophysiology of ROP. Potential mechanisms include dysregulation of vascular endothelial growth factor and insulin-like growth factor 1. Furthermore, the gut microbiome may be impacted by other known risk factors for ROP, such as intermittent hypoxia and sepsis treated with antibiotics. This mini-review summarizes the literature supporting these proposed avenues, establishing a foundation to guide future studies.

The Effects of Early Enteral and Parental Nutrition on Retinopathy of Prematurity: A Systematic Review

The management of preterm newborns must consider the severe problem of retinopathy of prematurity (ROP). A systematic review has been conducted to effectively acknowledge how enteral and parenteral early nutrition affect the growth and progression of ROP. The study summarizes recent findings from various sources to give insight into the relationship between dietary practices and ROP risks. When untreated, retinopathy of prematurity (ROP) may cause severe vision loss or blindness in premature newborns. The latter two phases of ROP progression are the most serious. A child's early nutrition, both orally and intravenously, significantly impacts the severity and progression of ROP. This systematic review aims to examine the evidence linking early nutrition to ROP in premature infants. The study used Embase, Scopus, and PubMed to conduct our search. ROP, premature newborns, and nutrition were keywords used to find relevant papers. Nine research studies made it through the screening process and offered important information on the impact of diet on ROP. These studies support the idea that poor nutrition is a driving force behind the onset of ROP. The risk of ROP has been associated with postnatal development, hyperglycemia, polyunsaturated fatty acid levels, and the presence of breast milk. The outlook for ROP has also been discovered to be affected by the length of time the patient has received parenteral feeding. The incidence and severity of ROP may be mitigated by providing better nutrition to premature newborns. This comprehensive study concludes that early nutrition, both enteral and parenteral, substantially influences the development and progression of ROP in premature newborns. The significance of nutrition in newborn care is highlighted by the possibility that improved dietary methods might aid in preventing and treating this vision-threatening illness.

Retinopathy of Prematurity: The Role of Nutrition

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness. ROP occurs in infants who are born very preterm. In ROP, retinal blood vessel development, which is prematurely arrested in preterm infants, is altered by perinatal exposures like oxygen and inflammation. Optimizing nutritional practices for preterm infants may mitigate the risk of ROP. In this article, we review the evidence that postnatal growth, hyperglycemia, polyunsaturated fatty acids, and breast milk provision may affect ROP risk. We also outline the current management strategies for ROP and describe the vision outcomes of children affected by ROP. [Pediatr Ann. 2023;52(8):e303-e308.].

The effect of sex on retinopathy of prematurity severity among premature mixed-sex multiple gestation infants

This retrospective study of 68 premature infants examined whether there was a difference between male and female mixed-sex multiple gestation infants with regard to stage of retinopathy of prematurity (ROP) developed or need for ROP treatment. We found that among mixed-sex twin infants there was no statistically significant difference between sexes in most severe ROP stage developed or need for ROP treatment, but males were treated at an earlier postmenstrual age (PMA) than females, despite females having a lower mean birthweight and slower mean growth velocity compared to males.

ASSESSMENT OF NEONATAL CARE STANDARD BY THE PREDICTIVE MODEL FOR RETINOPATHY OF PREMATURITY BASED ON WEIGHT GAIN

Care of extremely premature infants is in constant need for evaluation and progress. WINROP, a predictive model based on weight gain, has been developed to reduce the number of stressful examinations for retinopathy for prematurity. Validation studies of WINROP emphasize the difference of applicability in neonatal units of various practice. The aim of the study was to assess the standard of neonatal care by WINROP. Data on extremely premature infants were collected from medical records and entered in WINROP. High- and low-risk WINROP distribution and retinopathy of prematurity outcomes were analyzed. Fifty-four infants, gestational age ≤28 weeks, were included in the study after exclusion of weight related comorbidities. High risk was noted in 74% (n=40) of infants with 24% (n=13) developing retinopathy of prematurity requiring treatment. In low alarm group, there were 3 cases with severe disease. In conclusion, WINROP is not just a provider of predictive information on the severity of retinopathy of prematurity. High-risk alarm indicates the need of adjustment of nutritional strategies. Infants without pathological growth morbidities who develop severe retinopathy of prematurity in low-risk group point to other risk factors for retinopathy of prematurity to be evaluated and changed in future practice.

Quantification of Early Neonatal Oxygen Exposure as a Risk Factor for Retinopathy of Prematurity Requiring Treatment

Purpose

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness related to oxygen exposure in premature infants. Since oxygen monitoring protocols have reduced the incidence of treatment-requiring ROP (TR-ROP), it remains unclear whether oxygen exposure remains a relevant risk factor for incident TR-ROP and aggressive ROP (A-ROP), a severe, rapidly progressing form of ROP. The purpose of this proof-of-concept study was to use electronic health record (EHR) data to evaluate early oxygen exposure as a predictive variable for developing TR-ROP and A-ROP.

Design

Retrospective cohort study.

Participants

Two hundred forty-four infants screened for ROP at a single academic center.

Methods

For each infant, oxygen saturations and fraction of inspired oxygen (FiO₂) were extracted manually from the EHR until 31 weeks postmenstrual age (PMA). Cumulative minimum, maximum, and mean oxygen saturation and FiO₂ were calculated on a weekly basis. Random forest models were trained with 5-fold cross-validation using gestational age (GA) and cumulative minimum FiO₂ at 30 weeks PMA to identify infants who developed TR-ROP. Secondary receiver operating characteristic (ROC) curve analysis of infants with or without A-ROP was performed without cross-validation because of small numbers.

Main Outcome Measures

For each model, cross-validation performance for incident TR-ROP was assessed using area under the ROC curve (AUC) and area under the precision-recall curve (AUPRC) scores. For A-ROP, we calculated AUC and evaluated sensitivity and specificity at a high-sensitivity operating point.

Results

Of the 244 infants included, 33 developed TR-ROP, of which 5 developed A-ROP. For incident TR-ROP, random forest models trained on GA plus cumulative minimum FiO₂ (AUC = 0.93 ± 0.06; AUPRC = 0.76 ± 0.08) were not significantly better than models trained on GA alone (AUC = 0.92 ± 0.06 [P = 0.59]; AUPRC = 0.74 ± 0.12 [P = 0.32]). Models using oxygen alone showed an AUC of 0.80 ± 0.09. ROC analysis for A-ROP found an AUC of 0.92 (95% confidence interval, 0.87–0.96).

Conclusions

Oxygen exposure can be extracted from the EHR and quantified as a risk factor for incident TR-ROP and A-ROP. Extracting quantifiable clinical features from the EHR may be useful for building risk models for multiple diseases and evaluating the complex relationships among oxygen exposure, ROP, and other sequelae of prematurity.

Preterm nutrition and neurodevelopmental outcomes

Survival of preterm infants has been steadily improving in recent years because of many recent advances in perinatal and neonatal medicine. Despite these advances, the growth of survivors does not reach the ideal target level of the normal fetus of the same gestational age. Postnatal weight gain is often not achieved because extrauterine growth has higher energy requirements than intrauterine growth, due to the intensive care environment, illness and inadequate nutrition. Although many other factors influence infant brain development, including family socioeconomic and educational background, the role of nutrition is considerable and fortunately, amenable to intervention. In the preterm neonate, the brain is the most metabolically demanding organ, consuming the largest proportions of energy and nutrient intake for its function and programmed growth and maturation. Weight gain, linear and head circumference growth are all markers of nutritional status and are independently associated with long-term neurodevelopment. Brain development is not only the result of nutrients intake, but in addition, of the interaction with growth factors which depend on adequate nutrient supply and overall health status. This explains why conditions such as sepsis, necrotizing enterocolitis and chronic lung disease alter the distribution and accretion of nutrients thereby suppressing growth factor synthesis. In this review, we will focus on the direct role of nutrition on neurodevelopment, emphasizing why it should be started without delay. The nutritional requirements of the preterm infant will be discussed, followed by the effects of general nutritional interventions and specific nutrients, as well as the role of nutritional supplements on neurodevelopment. The primordial role of human breast milk, breast milk fortifiers and human milk oligosaccharides will be discussed in detail. We will also examine the role of nutrition in preventing neonatal complications which can affect neurodevelopment in their own right.

Oxidative Stress in Preterm Newborns

Preterm babies are highly susceptible to oxidative stress (OS) due to an imbalance between the oxidant and antioxidant systems. The generation of free radicals (FR) induces oxidative damage to multiple body organs and systems. OS is the main factor responsible for the development of typical premature infant diseases, such as bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia, kidney damage, eryptosis, and also respiratory distress syndrome and patent ductus arteriosus. Many biomarkers have been detected to early identify newborns at risk of developing a free radical-mediated disease and to investigate new antioxidant strategies. This review reports the current knowledge on OS in the preterm newborns and the newest findings concerning the use of OS biomarkers as diagnostic tools, as well as in implementing antioxidant therapeutic strategies for the prevention and treatment of these diseases and their sequelae.

Metabolism in Retinopathy of Prematurity

Retinopathy of prematurity is defined as retinal abnormalities that occur during development as a consequence of disturbed oxygen conditions and nutrient supply after preterm birth. Both neuronal maturation and retinal vascularization are impaired, leading to the compensatory but uncontrolled retinal neovessel growth. Current therapeutic interventions target the hypoxia-induced neovessels but negatively impact retinal neurons and normal vessels. Emerging evidence suggests that metabolic disturbance is a significant and underexplored risk factor in the disease pathogenesis. Hyperglycemia and dyslipidemia correlate with the retinal neurovascular dysfunction in infants born prematurely. Nutritional and hormonal supplementation relieve metabolic stress and improve retinal maturation. Here we focus on the mechanisms through which metabolism is involved in preterm-birth-related retinal disorder from clinical and experimental investigations. We will review and discuss potential therapeutic targets through the restoration of metabolic responses to prevent disease development and progression.

Novel multinutrient human milk-based human milk fortifier promotes growth and tolerance in premature infants

BACKGROUND

The objective of this study was to determine whether human milk supplemented with a novel human milk-based human milk fortifier (Novel HMF), compared with a bovine milk-based HMF (Bovine HMF), supports preterm infant growth through 36 weeks' postmenstrual age (PMA).

METHODS

This single-center, prospective trial compared growth and nutrition outcomes of preterm infants provided a human milk-based diet (mother's own milk or donor milk) supplemented with a Novel HMF with historic controls provided Bovine HMF. Preterm infants with an estimated gestational age (EGA) between 23 and 33 weeks' PMA and birth weight between 750 and 1800 g were eligible for study inclusion. Weight, length, and head circumference (HC) were monitored weekly. The occurrence of late-onset sepsis, nil per os (NPO) days, necrotizing enterocolitis, metabolic acidosis, and serious adverse events were monitored.

RESULTS

Birth weight, length, HC, and EGA were similar between the Novel HMF (n = 37) and Bovine HMF (n = 49) groups. The days to regain birth weight was shorter in the Novel HMF group (9.4 ± 4.0 vs 11.4 ± 4.8, P = .0343), with similar weight gain (g/day) from birth to 36 weeks' PMA. Adjusted weight growth velocity (g/kg/day) was significantly higher in the Novel HMF group at 14 and 21 days but similar at 36 weeks' PMA. The Novel HMF group experienced fewer NPO days with a similar total number of feeding days.

CONCLUSIONS

A novel, multinutrient, human milk-based HMF is well tolerated and meets the nutrition needs of preterm infants.

Systemic Factors Associated with a Thinner Choroid in Preterm Infants

Purpose

To identify systemic health factors associated with a thinner choroid, which has been hypothesized as a cause of poor visual outcomes in low–birth weight infants.

Design

The prospective, observational Study of Eye Imaging in Preterm Infants (BabySTEPS) enrolled infants recommended for retinopathy of prematurity screening based on the American Association of Pediatrics guidelines.

Participants

Infants who underwent imaging with investigational handheld OCT at 36 ± 1 weeks’ postmenstrual age (PMA) as part of BabySTEPS.

Methods

Average choroidal thickness was measured across the central subfoveal 1 mm. We concurrently collected maternal and infant clinical health data. Univariate and multivariate linear regression analyses were performed to evaluate factors associated with choroidal thickness. The left and right eyes showed similar thicknesses, so their average was used for analysis.

Main Outcomes Measures

Association between infant health factors and subfoveal choroidal thickness.

Results

Subfoveal choroidal thickness was measurable in 82 of 85 infants and 94% of eyes. Mean choroidal thickness was 231 ± 78 μm. In the univariate analysis, a thinner choroid was associated with decreased growth velocity (P < 0.001), lower birth weight (P < 0.001), smaller head circumference (P < 0.001), younger gestational age (P = 0.01), the presence of patent ductus arteriosus (P = 0.05), sepsis or necrotizing enterocolitis (P = 0.03), bronchopulmonary dysplasia (P = 0.03), pulmonary interstitial emphysema (P = 0.002), more days on oxygen support (P < 0.001), and being on oxygen support at 36 weeks (P < 0.001) and at the time of imaging (P < 0.001). In the multivariate analysis, growth velocity (P = 0.002) and oxygen support at the time of OCT imaging (P = 0.004) remained associated with a thinner choroid.

Conclusions

A thinner choroid is associated independently with growth velocity and receiving oxygen support at 36 ± 1 weeks PMA. This suggests that choroidal development in preterm infants may be related to growth rate in the first weeks of life and the prolonged use of supplemental oxygen. Longitudinal studies are needed to assess differences in choroidal thickness before 36 weeks PMA and to assess their impact on visual outcomes.

Complete blood count parameters to predict retinopathy of prematurity: when to evaluate and what do they tell us?

PURPOSE

To evaluate the relationship of novel inflammatory markers neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with retinopathy of prematurity (ROP) development and requirement for laser photocoagulation (LP) treatment.

METHODS

The charts of infants screened for ROP were reviewed retrospectively, and 120 newborns who had complete blood count (CBC) data in the first 24 hours after delivery (early period) and between 35 and 37th gestational weeks (late period) were included. Study population consisted of 34 infants who required LP for ROP treatment, 52 newborns with ROP that regressed without treatment, and 34 controls who did not developed any ROP stages. Demographics, etiological factors and CBC data including NLR and PLR values were noted. Risk factors for ROP development and treatment requirement were investigated using logistic regression analyses.

RESULTS

Significantly lower NLR was found in ROP cases compared to non-ROP group during late period (p = 0.003), while there was no difference in NLR during early period (p = 0.298). No significant difference was observed in PLR during both early and late periods (p = 0.230 and p = 0.349, respectively). Multivariate analysis revealed daily weight gain as major risk factor for ROP development (p = 0.001; OR: 0.870, 95% CI: 0.799-0.947), and hyperbilirubinemia as an independent risk factor for LP requirement (p = 0.045; OR: 0.204, 95% CI: 0.043-0.966).

CONCLUSION

NLR or PLR does not appear to be predictive risk factors for treatment requirement in cases with ROP. CBC values during first 24 h of life may be misleading; therefore, a late period CBC is recommended to evaluate prognostic factors for ROP development.

Perinatal determinants of growth trajectories in children born preterm

BACKGROUND

A growing amount of evidence indicates in utero and early life growth has profound, long-term consequences for an individual's health throughout the life course; however, there is limited data in preterm infants, a vulnerable population at risk for growth abnormalities.

OBJECTIVE

To address the gap in knowledge concerning early growth and its determinants in preterm infants.

METHODS

A retrospective cohort study was performed using a population of preterm (< 37 weeks gestation) infants obtained from an electronic medical record database. Weight z-scores were acquired from discharge until roughly two years corrected age. Linear mixed effects modeling, with random slopes and intercepts, was employed to estimate growth trajectories.

RESULTS

Thirteen variables, including maternal race, hypertension during pregnancy, preeclampsia, first trimester body mass index, multiple status, gestational age, birth weight, birth length, head circumference, year of birth, length of birth hospitalization stay, total parenteral nutrition, and dextrose treatment, were significantly associated with growth rates of preterm infants in univariate analyses. A small percentage (1.32% - 2.07%) of the variation in the growth of preterm infants can be explained in a joint model of these perinatal factors. In extremely preterm infants, additional variation in growth trajectories can be explained by conditions whose risk differs by degree of prematurity. Specifically, infants with periventricular leukomalacia or retinopathy of prematurity experienced decelerated rates of growth compared to infants without such conditions.

CONCLUSIONS

Factors found to influence growth over time in children born at term also affect growth of preterm infants. The strength of association and the magnitude of the effect varied by gestational age, revealing that significant heterogeneity in growth and its determinants exists within the preterm population.

Effects of nutrition therapy on growth, inflammation and metabolism in immature infants: a study protocol of a double-blind randomized controlled trial (ImNuT)

Background

Current nutritional management of infants born very preterm results in significant deficiency of the essential fatty acids (FAs) arachidonic acid (ARA) and docosahexaenoic acid (DHA). The impact of this deficit on brain maturation and inflammation mediated neonatal morbidities are unknown. The aim of this study is to determine whether early supply of ARA and DHA improves brain maturation and neonatal outcomes in infants born before 29 weeks of gestation.

Methods

Infants born at Oslo University Hospital are eligible to participate in this double-blind randomized controlled trial. Study participants are randomized to receive an enteral FA supplement of either 0.4 ml/kg MCT-oil™ (medium chain triglycerides) or 0.4 ml/kg Formulaid™ (100 mg/kg of ARA and 50 mg/kg of DHA). The FA supplement is given from the second day of life to 36 weeks’ postmenstrual age (PMA). The primary outcome is brain maturation assessed by Magnetic Resonance Imaging (MRI) at term equivalent age. Secondary outcomes include quality of growth, incidence of neonatal morbidities, cardiovascular health and neuro-development. Target sample size is 120 infants (60 per group), this will provide 80% power to detect a 0.04 difference in mean diffusivity (MD, mm²/sec) in major white matter tracts on MRI.

Discussion

Supplementation of ARA and DHA has the potential to improve brain maturation and reduce inflammation related diseases. This study is expected to provide valuable information for future nutritional guidelines for preterm infants.

Trial registration

Clinicaltrials.gov ID: NCT03555019. Registered 4 October 2018- Retrospectively registered.

ROP Screening Tool Assessment and Validation in a Third-Level Hospital in Argentina: A Pilot Study

PURPOSE

To evaluate whether a mathematical tool that predicts severe retinopathy of prematurity (ROP) using clinical parameters at 6 weeks of life (ROPScore calculator smartphone application; PABEX Corporation) can be useful to predict severe ROP in a population of premature infants in Argentina.

METHODS

In this retrospective study, data from the clinical records of all premature infants examined between 2012 and 2018 in the ophthalmology department of a public third-level hospital in Córdoba, Argentina, were obtained. ROPScore screening was applied using a Microsoft Excel spreadsheet (Microsoft Corporation). The sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values of the algorithm were analyzed.

RESULTS

Between 2012 and 2018, a total of 2,894 pre-term infants were examined and 411 met the inclusion criteria, of whom 34% (n = 139) presented some form of ROP and 6% (n = 25) developed severe forms that required treatment. The sensitivity of the algorithm for any ROP and severe ROP was 100%. The PPV and NPV were 35.64% and 100%, respectively, for any ROP and 9.88% and 100% for severe ROP.

CONCLUSIONS

One-time only calculation of the ROPScore algorithm could identify severe cases after validation, reducing the number of screened infants by 38% in infants with a birth weight of 1,500 g or less or a gestational age of 32 weeks or younger. [J Pediatr Ophthalmol Strabismus. 2021;58(1):55-61.].

Oxidative Stress Markers and the Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a leading cause of potentially preventable blindness in low birth weight preterm infants. Several perinatal and postnatal factors contribute to the incomplete maturation of retinal vascularization, leading to oxidative stress damage. Literature data suggest that the lack of equilibrium between pro-oxidants and anti-oxidants plays a key role. In the last decade, there has been an increasing interest in identifying the antecedents of ROP and the relevant pathogenic mechanisms involved. In this context, a panel of biomarkers was investigated in order to achieve early detection of oxidative stress occurrence and to prevent retinal damage. Several nutritional elements have been found to play a relevant role in ROP prevention. At this stage, no conclusive data have been shown to support the usefulness of one biomarker over another. Recently, the Food and Drugs Administration, the European Medicine Agency, and the National Institute of Health proposed a series of criteria in order to promote the inclusion of new biomarkers in perinatal clinical guidelines and daily practice. The aim of the present review is to offer an update on a panel of biomarkers, currently investigated as potential predictors of ROP, highlighting their strengths and weaknesses.

Progressive Metabolic Dysfunction and Nutritional Variability Precedes Necrotizing Enterocolitis

Necrotizing Enterocolitis (NEC) is associated with prematurity, enteral feedings, and enteral dysbiosis. Accordingly, we hypothesized that along with nutritional variability, metabolic dysfunction would be associated with NEC onset. Methods: We queried a multicenter longitudinal database that included 995 preterm infants (<32 weeks gestation) and included 73 cases of NEC. Dried blood spot samples were obtained on day of life 1, 7, 28, and 42. Metabolite data from each time point included 72 amino acid (AA) and acylcarnitine (AC) measures. Nutrition data were averaged at each of the same time points. Odds ratios and 95% confidence intervals were calculated using samples obtained prior to NEC diagnosis and adjusted for potential confounding variables. Nutritional and metabolic data were plotted longitudinally to determine relationship to NEC onset. Results: Day 1 analyte levels of alanine, phenylalanine, free carnitine, C16, arginine, C14:1/C16, and citrulline/phenylalanine were associated with the subsequent development of NEC. Over time, differences in individual analyte levels associated with NEC onset shifted from predominantly AAs at birth to predominantly ACs by day 42. Subjects who developed NEC received significantly lower weight-adjusted total calories (p < 0.001) overall, a trend that emerged by day of life 7 (p = 0.020), and persisted until day of life 28 (p < 0.001) and 42 (p < 0.001). Conclusion: Premature infants demonstrate metabolic differences at birth. Metabolite abnormalities progress in parallel to significant differences in nutritional delivery signifying metabolic dysfunction in premature newborns prior to NEC onset. These observations provide new insights to potential contributing pathophysiology of NEC and opportunity for clinical care-based prevention.

Late Growth and Changes in Body Composition Influence Odds of Developing Retinopathy of Prematurity among Preterm Infants

Background: While postnatal growth in the first month of life is known to impact retinopathy of prematurity (ROP) risk, the impact of growth later in hospitalization, during critical times of retinal vascularization, remains unknown. The purpose of this study was to assess if postnatal growth and body composition during the second half of neonatal intensive care unit hospitalization were associated with severity of retinopathy of prematurity in very low birth weight preterm infants. Methods: Prospective observational pilot study of 83 infants born <32 weeks gestation and <1500 g, conducted at a Level IV neonatal intensive care unit. Body composition was measured during the second half of hospitalization. Infants were evaluated for retinopathy of prematurity. Logistic regression was performed. Results: Greater gains in fat mass, fat-free mass, and percent body fat from 32 to 37 weeks postmenstrual age and higher % body fat at term postmenstrual age were associated with decreased odds of ≥stage 2 retinopathy of prematurity (p < 0.05). Conclusions: Improved growth later in neonatal intensive care unit hospitalization and increased adiposity at term may reduce odds of severe retinopathy of prematurity.

Simultaneous assessment of aberrant retinal vascularization, thickness, and function in an in vivo mouse oxygen-induced retinopathy model

BACKGROUND

Retinopathy of prematurity is a condition of abnormal retinal vascularization in premature infants. The effect of abnormal vascularization on retinal structure and function is unclear. In vivo studies of retinal vascularization, thickness, and function were performed in mice with oxygen-induced retinopathy (OIR mice).

METHODS

Eighteen mice were exposed to hyperoxia at postnatal day (P) 7, whereas 18 mice were raised in room air (RA). At P20 and 40, electroretinogram was performed for a-wave and b-wave amplitudes and peak times, followed by simultaneous fluorescein angiography for retinal avascular area, arterial tortuosity, and vein dilation assessments, and spectral domain optical coherence tomography for retinal thickness.

RESULTS

Capillary density appeared sparser in OIR mice, but retinal avascular area similar to RA mice. Retinal artery tortuosity was higher at P20 and P40 (P = 0.0001) in OIR than RA mice. OIR mice had dilated retinal veins at P20 and thinner inner retinas at P40. Retinal vein width positively correlated with inner retinal thickness (P = 0.008). b-wave amplitude was decreased in avascular retinal areas, and correlated with inner retinal thinning. b-wave peak time was prolonged in adult OIR mice at high intensities (P = 0.03).

CONCLUSIONS

Focal variations in retinal vascularization of OIR mice correlate with thickness and function. Adult OIR mice had increased retinal artery tortuosity, prolonged b-wave peak time, and decreased retinal vein width with inner retina attrition. These suggest abnormalities in inner retinal morphology or post-receptor signaling. Studying interactions between retinal vascular, structural, and functional changes could enhance knowledge of OIR pathogenesis and potential therapies.

Impact of early aggressive nutrition on retinal development in premature infants

The normal retinal development is interrupted by preterm birth and a retinopathy of prematurity (ROP) may develop as its consequence. ROP is characterized by aberrant vessel formation in the retina as a response to multiple risk factors influencing the process of retinal angiogenesis. Insulin-like growth factor I (IGF-1) and vascular endothelial growth factor (VEGF) play an important role in the process of normal retinal vascularization. Insufficient nutrition during the first 4 postnatal weeks results in low serum levels of IGF-1, which is essential for correct retinal vessels formation, ensuring survival of the newly formed endothelial cells. Low IGF-1 level results in stop of angiogenesis in the retina, leaving it avascular and prompting the onset of ROP. Keeping the newborns in a positive energetic balance by providing enough nutrients and energy has a beneficial impact on their growth, neurodevelopment and decreased incidence of ROP. The best way to achieve this is the early parenteral nutrition with the high content of nutrients combined with early enteral feeding by the own mother´s breast milk. Multiple studies confirmed the safety and efficacy of early aggressive nutrition but information about its long-term effects on the metabolism, growth and development is still needed.

Early energy and protein intakes and associations with growth, BPD, and ROP in extremely preterm infants

BACKGROUND & AIM

Extremely preterm infants face substantial neonatal morbidity. Nutrition is important to promote optimal growth and organ development in order to reduce late neonatal complications. The aim of this study was to examine the associations of early nutritional intakes on growth and risks of bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) in a high-risk population.

METHODS

This population-based cohort study includes infants born before 27 0/7 weeks of gestational age without severe malformations and surviving ≥10 days. Intake of energy and protein on postnatal days 4-6 and association with weight standard deviation score (WSDS) from birth to day 7, as well as intakes of energy and protein on postnatal days 4-6 and 7 to 27, respectively, and association with composite outcome of death and BPD and separate outcomes of BPD and ROP were examined, and adjusted for potential confounders.

RESULTS

The cohort comprised 296 infants with a median gestational age of 25 3/7 weeks. Expressed as daily intakes, every additional 10 kcal/kg/d of energy during days 4-6 was associated with 0.08 higher WSDS on day 7 (95% CI 0.06-0.11; p < 0.001). Between days 7 and 27, every 10 kcal/kg/d increase in energy intake was associated with a reduced risk of BPD of 9% (95% CI 1-16; p = 0.029) and any grade of ROP with a reduced risk of 6% (95% CI 2-9; p = 0.005) in multivariable models. This association was statistically significant in infants with ≤10 days of mechanical ventilation. In infants with >10 days of mechanical ventilation, a combined higher intake of energy and protein was associated with a reduced risk of BPD.

CONCLUSION

Early provision of energy and protein may reduce postnatal weight loss and risk of morbidity in extremely preterm infants.

The progress of prophylactic treatment in retinopathy of prematurity

Retinopathy of prematurity (ROP) is a retinal vascular disorder frequently found in premature infants. Different therapeutic strategies have been developed to treat ROP. However, there are still many children with ROP suffering by severe limitations in vision or even blindness. Recently, ROP has been suggested to be caused by abnormal development of the retinal vasculature, but not simply resulted by retinal neovascularization which takes about 4 to 6wk after birth in premature infants. Thus, instead of focusing on how to reduce retinal neovascularization, understanding the pathological changes and mechanisms that occur prior to retinal neovascularization is meaningful, which may lead to identify novel target(s) for the development of novel strategy to promote the healthy growth of retinal blood vessels rather than passively waiting for the appearance of retinal neovascularization and removing it by force. In this review, we discussed recent studies about, 1) the pathogenesis prior to retinal neovascularization in oxygen-induced retinopathy (OIR; a ROP in animal model) and in premature infants with ROP; 2) the preclinical and clinical research on preventive treatment of early OIR and ROP. We will not only highlight the importance of the mechanisms and signalling pathways in regulating early stage of ROP but also will provide guidance for actively exploring novel mechanisms and discovering novel treatments for early phase OIR and ROP prior to retinal neovascularization in the future.

Retinopathy of prematurity: a review of risk factors and their clinical significance

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disease that affects premature infants. Despite improvements in neonatal care and management guidelines, ROP remains a leading cause of childhood blindness worldwide. Current screening guidelines are primarily based on two risk factors: birth weight and gestational age; however, many investigators have suggested other risk factors, including maternal factors, prenatal and perinatal factors, demographics, medical interventions, comorbidities of prematurity, nutrition, and genetic factors. We review the existing literature addressing various possible ROP risk factors. Although there have been contradictory reports, and the risk may vary between different populations, understanding ROP risk factors is essential to develop predictive models, to gain insights into pathophysiology of retinal vascular diseases and diseases of prematurity, and to determine future directions in management of and research in ROP.

Improving Nutrition Outcomes for Infants < 1500 Grams With a Progressive, Evidenced-Based Enteral Feeding Protocol

BACKGROUND

Growth is essential for very low birth weight infants. The purpose of this retrospective chart review was to evaluate the impact of a new standardized, evidenced-based feeding protocol for infants born < 1500 g in correlation with growth and clinical outcomes.

METHODS

Growth and nutrition data was reviewed from 2 groups of infants born < 1500 g within a level III newborn intensive care unit (NICU). Epoch 1 infants (N = 32) received care following initial implementation of a standardized enteral feeding protocol. Epoch 2 infants (N = 32) received care following aggressive modification of this initial protocol based on newly available literature that promotes earlier initiation and advancement of enteral feedings.

RESULTS

Epoch 2 infants weighed more at 36 weeks (2562 vs 2304 g) with higher discharge weight percentiles (32nd vs 15th percentile). Epoch 2 infants started and achieved full enteral feedings earlier (day of life 1 vs 4; 7 vs 22, P < 0.0001) and required less days of parenteral nutrition (5.5 vs 17.5 days, P < 0.0001), with indwelling central line for parenteral access (6 vs 17.5). There were no differences in retinopathy of prematurity (17% control vs 19% study), oxygen requirement at 36 weeks (22% epoch 1 vs 43%), necrotizing enterocolitis (3% epoch 1 vs 0%), intraventricular hemorrhage grade 3-4, periventricular leukomalacia, or death.

CONCLUSION

In this sample of very low birth weight infants, a progressive standardized, evidence-based feeding protocol was associated with improved growth without increased risk for necrotizing enterocolitis.

Neonatal Morbidity Count Is Associated With a Reduced Likelihood of Achieving Recommendations for Protein, Lipid, and Energy in Very Low Birth Weight Infants: A Prospective Cohort Study

BACKGROUND

Serious morbidity may elevate nutrient requirements and affect adherence to feeding guidelines for very low birth weight (VLBW) infants. An understanding of factors affecting nutrient intakes of VLBW infants will facilitate development of strategies to improve nutrient provision. Our aim was to examine the impact of neonatal morbidity count on achieving recommended nutrient intakes in VLBW infants.

METHODS

VLBW infants enrolled in the Donor Milk for Improved Neurodevelopmental Outcomes trial (ISRCTN35317141, n = 363) were included. Serious morbidities and daily parenteral and enteral intakes were collected prospectively.

RESULTS

Median intakes of infants with and without ≥1 morbidity met protein recommendations (3.5-4.5 g/kg/d) by week 2, although not maintained after week 4. Infants with ≥1 morbidity (vs without) were 2 weeks slower in achieving lipid (4.8-6.6 g/kg/d; week 4 vs 2) and energy (110-130 kcal/kg/d; week 5 vs 3) and 1 week slower in achieving carbohydrate recommendations (11.6-13.2 g/kg/d; week 4 vs 3). Adjusted hazard ratios of first achieving recommendations on any given day in infants with any 1 or 2 morbidities were 0.6 (95% confidence interval [CI], 0.5-0.9) and 0.6 (0.4-0.9), respectively, for protein; 0.5 (0.4-0.7) and 0.3 (0.2-0.5) for lipid; and 0.5 (0.4-0.7) and 0.3 (0.2-0.4) for energy.

CONCLUSION

Morbidity is associated with a decreased likelihood of achieving lipid and consequently energy recommendations. This and the decline in protein intakes after the early neonatal period require further investigation to ensure optimal nutrition in this vulnerable population.

Early postnatal hyperglycaemia is a risk factor for treatment-demanding retinopathy of prematurity

BACKGROUND

To investigate whether neonatal hyperglycaemia in the first postnatal week is associated with treatment-demanding retinopathy of prematurity (ROP).

METHODS

This is a Danish national, retrospective, case-control study of premature infants (birth period 2003-2006). Three national registers were searched, and data were linked through a unique civil registration number. The study sample consisted of 106 cases each matched with two comparison infants. Matching criteria were gestational age (GA) at birth, ROP not registered and born at the same neonatal intensive care unit. Potential 'new' risk factors were analysed in a multivariate logistic regression model, while adjusted for previously recognised risk factors (ie, GA at birth, small for gestational age, multiple birth and male sex).

RESULTS

Hospital records of 310 preterm infants (106 treated; 204 comparison infants) were available. Nutrition in terms of energy (kcal/kg/week) and protein (g/kg/week) given to the preterm infants during the first postnatal week were statistically insignificant between the study groups (Mann-Whitney U test; p=0.165/p=0.163). Early postnatal weight gain between the two study groups was borderline significant (t-test; p=0.047). Hyperglycaemic events (indexed value) were statistically significantly different between the two study groups (Mann-Whitney U test; p<0.001). Hyperglycaemia was a statistically independent risk factor (OR: 1.022; 95% CI 1.002 to 1.042; p=0.031).

CONCLUSION

An independent association was found between the occurrence of hyperglycaemic events during the first postnatal week and later development of treatment-demanding ROP, when adjusted for known risk factors.

Impact of Early Nutritional Intake on Preterm Brain: A Magnetic Resonance Imaging Study

OBJECTIVES

To investigate the association between early nutritional intake and brain development assessed by magnetic resonance imaging (MRI).

STUDY DESIGN

A cohort of neonates born at ≤30 weeks gestational age underwent MRI at term equivalent age. Brain maturation and injury were assessed using the Kidokoro score. Two groups were defined by severity of the scores. The associations between macronutrients intake during the first 2 weeks of life, clinical factors, and imaging scores were analyzed using logistic regression.

RESULTS

MRI scores from group 1 patients (n = 27) were normal to mildly abnormal (0-5). Group 2 (n = 15) had more abnormal scores (6-12). The median gestational ages (IQR) were 27.4 (1.9) weeks in group 1 and 27.0 (2.9) weeks in group 2, with birth weights of 900 (318) g (group 1) and 844 (293) g (group 2). In group 2, energy, lipid, and carbohydrate intake were significantly lower than in group 1. Group 2 also showed higher rates of sepsis and clinical risk scores than group 1. After adjustments in bivariate models, higher energy and lipid intake remained significantly associated with improved scores on MRI. This association was stronger for the gray matter component of the score.

CONCLUSIONS

Higher energy and lipid intake during the first 2 weeks after birth was associated with a lower incidence of brain lesions and dysmaturation at term equivalent age in preterm neonates.

Peripherally inserted central catheters optimize nutrient intake in moderately preterm infants

BACKGROUND

While very preterm (<32 wk gestation) infants are routinely provided intensive nutritional support via central line, clinical practice varies for nutrient delivery in infants born moderately preterm (32-34 wk gestation). We sought to define the impact of nutritional support via peripherally inserted central catheter (PICC) on nutrient delivery in the first 2 wk of life and growth by discharge.

METHODS

Data were extracted from the records of 187 infants born between 32 and 34 6/7 wk gestation and admitted to the University of Iowa Children's Hospital between April 2012 and December 2013. Records of all feedings, weights, and PICC placements were collected. The growth outcomes at discharge for infants who received nutrition via PICC were compared to those who did not.

RESULTS

In the first week of life, newborns who received nutrition via PICC line received 17.6 more kilocalories (confidence interval (CI): 12.5-22.7, P < 0.001) and 1.2 more grams protein per kilogram body weight per day (CI: 0.9-1.4, P < 0.001) compared to control infants. By discharge, the PICC group had gained 302 g more body weight (P < 0.001).

CONCLUSION

This study demonstrates superior nutrient intake and growth in the first 2 wk of life for infants who received nutrition via PICC line.

Low energy intake during the first 4 weeks of life increases the risk for severe retinopathy of prematurity in extremely preterm infants

OBJECTIVES

Poor weight gain during the first weeks of life in preterm infants is closely associated with the risk of developing the retinopathy of prematurity (ROP) and insufficient nutrition might be an important contributing factor. This study aimed to evaluate the effect of energy and macronutrient intakes during the first 4 weeks of life on the risk for severe ROP (stages 3-5).

STUDY DESIGN

A population-based study including all Swedish extremely preterm infants born before 27 gestational weeks during a 3-year period. Each infant was classified according to the maximum stage of ROP in either eye as assessed prospectively until full retinal vascularisation. The detailed daily data of actual intakes of enteral and parenteral nutrition and growth data were obtained from hospital records.

RESULTS

Of the included 498 infants, 172 (34.5%) had severe ROP and 96 (19.3%) were treated. Energy and macronutrient intakes were less than recommended and the infants showed severe postnatal growth failure. Higher intakes of energy, fat and carbohydrates, but not protein, were significantly associated with a lower risk of severe ROP. Adjusting for morbidity, an increased energy intake of 10 kcal/kg/day was associated with a 24% decrease in severe ROP.

CONCLUSIONS

We showed that low energy intake during the first 4 weeks of life was an independent risk factor for severe ROP. This implies that the provision of adequate energy from parenteral and enteral sources during the first 4 weeks of life may be an effective method for reducing the risk of severe ROP in extremely preterm infants.

Human milk feeding protects very low-birth-weight infants from retinopathy of prematurity: a pre-post cohort analysis

OBJECTIVES

To examine the effect of early human milk (HM) feeding on the incidence of retinopathy of prematurity (ROP) among very low-birth-weight (VLBW) infants.

METHODS

Observational cohort research in a Level III neonatal intensive care unit. A total of 186 infants were enrolled in this pre-post cohort study (114 infants were included in the HM-fed group and 72 in the formula-fed group). ROP, type of feeding (early exclusive HM versus any formula), and potential confounding variables were measured. Differences between groups were explored.

RESULTS

The clinical characteristics of the neonates did not differ between the two groups. By bivariate analysis, HM feeding was associated with 75% lower odds of Stage 2 or 3 ROP (OR = 0.25, 95% CI: 0.091 to 0.705; p = 0.009) At multivariate logistic regression, type of milk feeding retained significance, exclusive HM being protective with p = 0.002.

CONCLUSIONS

This study found an association between early exposure to formula in VLBW infants and ROP. An initial HM diet, devoid of cow milk-containing products before achieving full enteral feeding, may help prevent ROP.

Growth and Tolerance of Preterm Infants Fed a New Extensively Hydrolyzed Liquid Human Milk Fortifier

OBJECTIVES

This study was a comparison of growth and tolerance in premature infants fed either standard powdered human milk fortifier (HMF) or a newly formulated concentrated liquid that contained extensively hydrolyzed protein.

METHODS

This was an unblinded randomized controlled multicenter noninferiority study on preterm infants receiving human milk (HM) supplemented with 2 randomly assigned HMFs, either concentrated liquid HMF containing extensively hydrolyzed protein (LE-HMF) or a powdered intact protein HMF (PI-HMF) as the control. The study population consisted of preterm infants ≤33 weeks who were enterally fed HM. Infants were studied from the first day of HM fortification until day 29 or hospital discharge, whichever came first.

RESULTS

A total of 147 preterm infants were enrolled. Noninferiority was observed in weight gain reported in the intent-to-treat (ITT) analysis was 18.2 and 17.5 g · kg(-1) · day(-1) for the LE-HMF and PI-HMF groups, respectively. In an a priori defined subgroup of strict protocol followers (n = 75), the infants fed LE-HMF achieved greater weight over time than those fed PI-HMF (P = 0.036). The LE-HMF group achieved greater linear growth over time compared to the PI-HMF (P = 0.029). The protein intake from fortified HM was significantly higher in the LE-HMF group compared with the PI-HMF group (3.9 vs 3.3 g · kg(-1) · day(-1), P < 0.0001). Both fortifiers were well tolerated with no significant differences in overall morbidity.

CONCLUSIONS

Both fortifiers showed excellent weight gain (grams per kilograms per day), tolerance, and low incidence of morbidity outcomes with the infants who were strict protocol followers fed LE-HMF having improved growth during the study. These data point to the safety and suitability of this new concentrated liquid HMF (LE-HMF) in preterm infants. Growth with this fortifier closely matches the recent recommendations for a weight gain of >18 g · kg(-1) · day(-1).

Balancing the risks and benefits of parenteral nutrition for preterm infants: can we define the optimal composition?

Nutrient intakes in preterm infants are frequently inadequate and are associated with worse neuro-developmental outcome. Preterm infants take time to establish enteral intakes, and parenteral nutrition (PN) is now an integral component of care. Despite this, the evidence base for PN intakes is extremely limited. There remains uncertainty over safe initial and maximum amounts of macronutrients, and the optimal amino acid and lipid composition. Studies have tended to focus on short-term growth measures and there are few studies with long-term follow-up. There may be a tradeoff between improving cognitive outcomes while minimising metabolic harm that means determining the optimal regimen will require long-term follow-up. Given the importance of appropriate nutrition for long-term metabolic and cognitive health, and the associated healthcare costs, optimising the composition of PN deserves to be seen as a research priority in neonatal medicine.

Avoiding postnatal undernutrition of VLBW infants during neonatal intensive care: evidence and personal view in the absence of evidence

Inadequate nutrient intakes in the first postnatal weeks play a crucial role in the aetiology of postnatal growth restriction of very low birthweight (VLBW) infants. Efforts to improve early nutrition in these infants led to a significant reduction in postnatal growth failure. Initiation of enhanced parenteral nutrition immediately after birth and utilisation of the large potential of early enteral nutrition seem pivotal. Nevertheless, it remains challenging to further reduce the initial drop in weight and head circumference z-score and to improve body composition and linear growth. This review will summarise data on how near-fetal postnatal weight gain in VLBW infants can be achieved and makes suggestions for early nutrition of VLBW infants.

Retinopathy of prematurity

Premature infants born at 30 weeks' gestational age or younger, or 1500 g or smaller, are screened for retinopathy of prematurity (ROP). Guidelines for supplemental oxygen in neonatal intensive care units have decreased but not eliminated the incidence of severe ROP. The underlying cause for ROP is prematurity and low birth weight, and with the survival of smaller and younger babies, ROP continues to be a significant problem facing premature infants. Threshold ROP is treated with retinal photocoagulation, but newer treatments such as intraocular injections of bevacizumab (Avastin) are being used alone or in conjunction with laser.

The role of the human leukocyte antigen system in retinopathy of prematurity: a pilot study

AIM

To assess the association between the human leukocyte antigen system and retinopathy of prematurity.

METHODS

Neonates of <32 weeks of gestational age, born at two level III neonatal intensive care units from January 2000 to December 2001 and from January 2006 to June 2009, were included in the study. Demographic and clinical data were recorded, and retinopathy was classified according to the International Classification. Epithelial cells were collected from the oral cavity and the HLA were studied using the PCR/SSO method. Univariate and multivariate analyses were performed using SPSS® v.18.

RESULTS

We evaluated 156 neonates, including 82 (52.6%) males. Median gestational age was 29 (23-31) weeks, and median birth weight was 1030 (525-1935) grams. Seventy (44.9%) of the neonates developed retinopathy. Alleles HLA-B*38, HLA-Cw*12, HLA-DRB1*09, HLA-DRB1*14 (univariate analysis) and HLA-A*68 and HLA-Cw*12 were associated to retinopathy (multivariate analysis).

CONCLUSION

The results suggest that the HLA system may be associated with the development of retinopathy of prematurity. A large-scale population-based study should be performed to clarify this association.