Vitamin A and infancy. Biochemical, functional, and clinical aspects

The role of nutritional interventions in the prevention and treatment of chronic lung disease of prematurity

Chronic lung disease of prematurity or bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Nutrition may affect incidence and severity of BPD. In this context, the Section on Nutrition, Gastroenterology and Metabolism, the Pulmonary Section of the European Society for Paediatric Research (ESPR) and SPR have joined forces to review the current knowledge on nutritional issues related to BPD. The aim of this narrative review is to discuss the clinical implications for nutritional practice. Nutrient deficiencies may influence pathogenesis of BPD. Adequate nutrition and growth can play a crucial role in the prevention of and recovery from BPD. Optimal nutrition strategy is an important principle, especially in the early postnatal period. As optimal energy intake in infants at risk of BPD or with evolving BPD is not yet defined, further research with well-designed studies on nutritional strategies for preterm infants with BPD is urgently needed. IMPACT: Based on current evidence it seems reasonable to recommend that BPD diagnosed infants should receive an energy supply ranging from 120 to 150 Kcal/kg/d. Exclusive MOM feed with adequate fortification should be encouraged as this is associated with a significant reduction in the risk of BPD. Suboptimal nutritional delivery is often seen in preterm infants with BPD compared to controls.

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.

Reducing stillbirths: behavioural and nutritional interventions before and during pregnancy

BACKGROUND

The vast majority of global stillbirths occur in low- and middle-income countries, and in many settings, the majority of stillbirths occur antenatally, prior to the onset of labour. Poor nutritional status, lack of antenatal care and a number of behaviours increase women's risk of stillbirth in many resource-poor settings. Interventions to reduce these risks could reduce the resulting burden of stillbirths, but the evidence for the impact of such interventions has not yet been comprehensively evaluated.

METHODS

This second paper of a systematic review of interventions that could plausibly impact stillbirth rates covers 12 different interventions relating to behavioural and socially mediated risk factors, including exposures to harmful practices and substances, antenatal care utilisation and quality, and maternal nutrition before and during pregnancy. The search strategy reviewed indexed medical journals on PubMed and the Cochrane Library. If any eligible randomised controlled trials were identified that were published after the most recent Cochrane review, they were added to generate new meta-analyses. Interventions covered in this paper have a focus on low- and middle-income countries, both because of the large burden of stillbirths and because of the high prevalence of risk factors including maternal malnutrition and harmful environmental exposures. The reviews and studies belonging to these interventions were graded and conclusions derived about the evidence of benefit of these interventions.

RESULTS

From a programmatic perspective, none of the interventions achieved clear evidence of benefit. Evidence for some socially mediated risk factors were identified, such as exposure to indoor air pollution and birth spacing, but still require the development of appropriate interventions. There is a need for additional studies on culturally appropriate behavioural interventions and clinical trials to increase smoking cessation and reduce exposure to smokeless tobacco. Balanced protein-energy supplementation was associated with reduced stillbirth rates, but larger well-designed trials are required to confirm findings. Peri-conceptional folic acid supplementation significantly reduces neural tube defects, yet no significant associated reductions in stillbirth rates have been documented. Evidence for other nutritional interventions including multiple micronutrient and Vitamin A supplementation is weak, suggesting the need for further research to assess potential of nutritional interventions to reduce stillbirths.

CONCLUSION

Antenatal care is widely used in low- and middle-income countries, and provides a natural facility-based contact through which to provide or educate about many of the interventions we reviewed. The impact of broader socially mediated behaviors, such as fertility decision-making, access to antenatal care, and maternal diet and exposures like tobacco and indoor air pollution during pregnancy, are poorly understood, and further research and appropriate interventions are needed to test the association of these behaviours with stillbirth outcomes. For most nutritional interventions, larger randomised controlled trials are needed which report stillbirths disaggregated from composite perinatal mortality. Many antepartum stillbirths are potentially preventable in low- and middle-income countries, particularly through dietary and environmental improvement, and through improving the quality of antenatal care - particularly including diagnosis and management of high-risk pregnancies - that pregnant women receive.

Vitamin A and preterm infants: what we know, what we don't know, and what we need to know

Vitamin A is essential for optimal growth and development. In the developing world, vitamin A supplementation of the newborn infant reduces mortality. In the developed world, extremely preterm infants are born with low body stores of vitamin A and are at high risk of vitamin A deficiency. Optimal vitamin A supplementation for this population is not clearly defined, however, and, despite evidence of benefit, early vitamin A supplementation of extremely preterm infants is not uniformly practised in the United Kingdom. There is an urgent need for studies in preterm infants that include quantification of hepatic stores and functional assessment of vitamin A status as well as long term outcome.

Vitamin A and Bronchopulmonary Dysplasia: Research, Issues, and Clinical Practice

Vitamin A is a crucial antioxidant for preterm infants because it protects the lungs from oxidative damage induced by the administration of supplemental oxygen. Although all preterm infants are born with smaller vitamin A stores than full-term infants, the store of vitamin A in preterm infants at risk for bronchopulmonary dysplasia (BPD) is often especially deficient. Despite the increases in plasma vitamin A concentrations that have been achieved with vitamin A supplementation, only modest improvements in clinical outcomes and incidence of BPD have been noted in this population. This article reviews the research on vitamin A supplementation for preterm infants, as well as the issues and clinical implications associated with this intervention.