Lung function evolution in children with old and new type bronchopulmonary dysplasia: a retrospective cohort analysis

Lactobacillus plantarum L168 improves hyperoxia-induced pulmonary inflammation and hypoalveolarization in a rat model of bronchopulmonary dysplasia

Alteration of gut microbiota can affect chronic lung diseases, such as asthma and chronic obstructive pulmonary disease, through abnormal immune and inflammatory responses. Previous studies have shown a feasible connection between gut microbiota and bronchopulmonary dysplasia (BPD) in preterm infants. However, whether BPD can be ameliorated by restoring the gut microbiota remains unclear. In preterm infants with BPD, we found variance in the diversity and structure of gut microbiota. Similarly, BPD rats showed gut dysbiosis, characterized by a deficiency of Lactobacillus, which was abundant in normal rats. We therefore explored the effect and potential mechanism of action of a probiotic strain, Lactobacillus plantarum L168, in improving BPD. The BPD rats were treated with L. plantarum L168 by gavage for 2 weeks, and the effect was evaluated by lung histopathology, lung function, and serum inflammatory markers. Subsequently, we observed reduced lung injury and improved lung development in BPD rats exposed to L. plantarum L168. Further evaluation revealed that L. plantarum L168 improved intestinal permeability in BPD rats. Serum metabolomics showed altered inflammation-associated metabolites following L. plantarum L168 intervention, notably a marked increase in anti-inflammatory metabolites. In agreement with the metabolites analysis, RNA-seq analysis of the intestine and lung showed that inflammation and immune-related genes were down-regulated. Based on the information from RNA-seq, we validated that L. plantarum L168 might improve BPD relating to down-regulation of TLR4 /NF-κB /CCL4 pathway. Together, our findings suggest the potential of L. plantarum L168 to provide probiotic-based therapeutic strategies for BPD.

An Update on Lung Function of Extremely and Very Preterm Infants in Later Life: The Role of Early Nutritional Interventions

Birth occurring at ≤32 weeks' gestation ("very preterm") or at ≤28 weeks' gestation ("extremely preterm") potentially poses considerable health problems for the neonate, including respiratory sequelae, not only during the immediate newborn period, but throughout childhood and into adulthood. With the progressive improvements in neonatal care, the survival of extremely preterm and very preterm neonates has improved substantially. However, a considerable percentage of these infants suffer dysfunctions that may trigger, at some stage later in life, the onset of respiratory morbidities. The interruption of the normal development of the respiratory tract caused by preterm birth, in combination with postnatal lung injury caused by various interventions, e.g., mechanical ventilation and oxygen therapy, increases the risk ofthe development of long-term respiratory deficits in survivors. Those infants that are most affected are those who develop chronic lung disease of prematurity (also called bronchopulmonary dysplasia, BPD), but impaired lung function can develop irrespective of BPD diagnosis. Apart from indicating abnormal lung function in survivors of extreme prematurity, recent long-term follow-up studies also emphasize the crucial role of early nutritional intake as an effective strategy, which promotes lung growth and repair. This article will update the associations between extremely/very preterm birth with long-term respiratory outcomes. It will also discuss the protective effect of nutritional interventions, focusing on recently published follow-up data.

Nutrition of Infants with Bronchopulmonary Dysplasia before and after Discharge from the Neonatal Intensive Care Unit

Bronchopulmonary dysplasia (BPD) represents a severe sequela in neonates born very prematurely. The provision of adequate nutritional support in this high-risk population is challenging. The development of the lungs and physical growth are closely linked together in infants with BPD. Growth deficiency has been associated with pulmonary dysfunction, whereas improvement in respiratory status results in growth acceleration. Currently, there is not enough data regarding optimal nutritional strategies in this population. Nutrition in these infants should provide sufficient calories and nutrients to establish growth, avoid growth retardation and assist alveolarization of the lungs. Meticulous follow-up is mandatory during and after discharge from the Neonatal Intensive care Unit (NICU) to minimize growth retardation and improve lung function. Despite the significant literature supporting the contribution of growth and nutrition in the avoidance of BPD, there is limited research regarding interventions and management of infants with established BPD. Our aim was to review clinical strategies applied in everyday clinical practice and identify debates on the nutritional approach of newborns with BPD. Well-organized interventions and clinical trials regarding the somatic development and nutrition of infants with BPD are warranted.

Physiological aspects of cardiopulmonary dysanapsis on exercise in adults born preterm

Progressive improvements in perinatal care and respiratory management of preterm infants have resulted in increased survival of newborns of extremely low gestational age over the past few decades. However, the incidence of bronchopulmonary dysplasia, the chronic lung disease after preterm birth, has not changed. Studies of the long-term follow-up of adults born preterm have shown persistent abnormalities of respiratory, cardiovascular and cardiopulmonary function, possibly leading to a lower exercise capacity. The underlying causes of these abnormalities are incompletely known, but we hypothesize that dysanapsis, i.e. discordant growth and development, in the respiratory and cardiovascular systems is a central structural feature that leads to a lower exercise capacity in young adults born preterm than those born at term. We discuss how the hypothesized system dysanapsis underscores the observed respiratory, cardiovascular and cardiopulmonary limitations. Specifically, adults born preterm have: (1) normal lung volumes but smaller airways, which causes expiratory airflow limitation and abnormal respiratory mechanics but without impacts on pulmonary gas exchange efficiency; (2) normal total cardiac size but smaller cardiac chambers; and (3) in some cases, evidence of pulmonary hypertension, particularly during exercise, suggesting a reduced pulmonary vascular capacity despite reduced cardiac output. We speculate that these underlying developmental abnormalities may accelerate the normal age-associated decline in exercise capacity, via an accelerated decline in respiratory, cardiovascular and cardiopulmonary function. Finally, we suggest areas of future research, especially the need for longitudinal and interventional studies from infancy into adulthood to better understand how preterm birth alters exercise capacity across the lifespan.

The Consensus Definition of Bronchopulmonary Dysplasia Is an Adequate Predictor of Lung Function at Preschool Age

BACKGROUND

Recent attempts to refine the definition bronchopulmonary dysplasia (BPD) have based its predictive capacity on respiratory outcome in the first 2 years of life, eliminating the pre-existing requirement of 28 days of oxygen therapy prior to 36 weeks postmenstrual age (PMA). The objective of this study was to assess the utility of the 2001 consensus definition in predicting impaired lung function at preschool age.

METHODS

This cohort study included children aged 4-6 years old who were born at gestational age (GA) <32 weeks or bodyweight <1500 g. Univariate and multivariate analyses were performed to assess differences in antenatal and neonatal variables between BPD and non-BPD children. All participants underwent incentive spirometry. Lung function parameters were contrasted with the Global Lung Function Initiative (GLI-2012) reference equations and, together with antenatal and neonatal variables, compared among the different subgroups (no BPD, mild BPD, and moderate-to-severe BPD). A multivariate model was generated to identify independent risk factors for impaired lung function.

RESULTS

GA, hemodynamically significant patent ductus arteriosus, and late sepsis were independent risk factors for the development of BPD. A total of 119 children underwent incentive spirometry. All lung function parameters were significantly altered relative to reference values. Greater impairment of lung function was observed in the mild BPD vs. the no BPD group (forced expiratory volume in the first 0.75 seconds [FEV_0.75]: -1.18 ± 0.80 vs. -0.55 ± 1.13; p = 0.010), but no difference in forced vital capacity (FVC) was observed (-0.32 ± 0.90 vs. -0.18 ± 1; p = 0.534). The moderate-to-severe BPD group exhibited the most severe FEV_0.75 reduction (FEV_0.75: -2.63 ± 1.18 vs. -0.72 ± 1.08; p = 0.000) and was the only condition with FVC impairment (FVC: -1.82 ± 1.12 vs. -0.22 ± 0.87; p = 0.000). The multivariate analysis identified a diagnosis of moderate-to-severe BPD as an independent risk factor for lung function impairment.

CONCLUSION

The 2001 consensus definition of BPD has adequate predictive capacity for lung function measured by spirometry at 4-6 years of age. Moderate-to-severe BPD was the best predictor of respiratory impairment. Children with mild BPD showed greater alteration of FEV_0.75 than those without BPD.

Respiratory and cardiopulmonary limitations to aerobic exercise capacity in adults born preterm

Adults born preterm, regardless of whether they develop bronchopulmonary dysplasia, have underdeveloped respiratory and cardiopulmonary systems. The resulting impaired respiratory and cardiopulmonary systems are inadequate for the challenges imposed by aerobic exercise, which is exacerbated by the presence of bronchopulmonary dysplasia. Thus the respiratory and cardiopulmonary systems of these preterm individuals may be the most influential contributors to the significantly lower aerobic exercise capacity compared with their term born counterparts. The precise underlying cause(s) of the lower aerobic exercise capacity in adults born preterm is not entirely known but could be a number of interrelated parameters including mechanical ventilatory constraints, impaired pulmonary gas exchange efficiency, and excessive cardiopulmonary pressures. Likewise, additional aspects, such as impaired cardiovascular function and altered muscle bioenergetics, may play additional roles in limiting aerobic exercise capacity. Whether or not all or some of these aspects are present in adults born preterm and precisely how they may contribute to the lower aerobic exercise capacity are only beginning to be systematically explored. The purpose of this mini-review is to outline what is currently known about the respiratory and cardiopulmonary limitations during exercise in this population and to identify key areas where additional knowledge will help to advance this area. Additionally, where possible, we highlight the similarities and differences between obstructive lung disease resulting from preterm birth and chronic obstructive pulmonary disease (COPD) as the physiology and pathophysiology of these two forms of obstructive lung disease may not be identical.