• Clinical and Experimental Pediatrics
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• v.53 no.12
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• pp.979-984
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• 2010

Recent progress in neonatal medicine has enabled survival of many extremely low-birth-weight infants. Prenatal steroids, surfactants, and non-invasive ventilation have helped reduce the incidence of the classical form of bronchopulmonary dysplasia characterized by marked fibrosis and emphysema. However, a new form of bronchopulmonary dysplasia marked by arrest of alveolarization remains a complication in the postnatal course of extremely low-birth-weight infants. To better understand this challenging complication, detailed alveolarization mechanisms should be delineated. Proper alveolarization involves the temporal and spatial coordination of a number of cells, mediators, and genes. Cross-talk between the mesenchyme and the epithelium through soluble and diffusible factors are key processes of alveolarization. Lung interstitial cells derived from the mesenchyme play a crucial role in alveolarization. Peak alveolar formation coincides with intense lung interstitial cell proliferation. Myofibroblasts are essential for secondary septation, a critical process of alveolarization, and localize to the front lines of alveologenesis. The differentiation and migration of myofibroblasts are strictly controlled by various mediators and genes. Disruption of this finely controlled mechanism leads to abnormal alveolarization. Since arrest in alveolarization is a hallmark of a new form of bronchopulmonary dysplasia, knowledge regarding the role of lung interstitial cells during alveolarization and their control mechanism will enable us to find more specific therapeutic strategies for bronchopulmonary dysplasia. In this review, the role of lung interstitial cells during alveolarization and control mechanisms of their differentiation and migration will be discussed.

• Clinical and Experimental Pediatrics
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• v.62 no.10
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• pp.367-373
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• 2019

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants with multiple factors affected from prenatal to postnatal periods. Despite significant advances in neonatal care over almost 50 years, BPD rates have not decreased; in fact, they may have even increased. Since more preterm infants, even at periviable gestational age, survive today, different stages of lung development affect the pathogenesis of BPD. Hence, the definition of BPD has changed from "old" to "new." In this review, we discuss the various definitions of BPD, risk factors from the prenatal to postnatal periods, management strategies by phase, and future directions for research.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.6-13
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• 2009

Recent advances in perinatal care have resulted in improved survival of extremely low birth weight infants (ELBWI). However, bronchopulmonary dysplasia (BPD) remains one of the major complications in ELBWI. BPD was originally described over 40 years ago; the clinical characteristics, epidemiology, and pathogenesis of BPD have changed markedly through this period. In this article, I have reviewed recent progress in research concerning the clinical presentation and characteristics, epidemiology, and pathogenesis of BPD.

• Clinical and Experimental Pediatrics
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• v.57 no.4
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• pp.171-177
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• 2014

Purpose: Eosinophilia is common in premature infants, and its incidence increases with a shorter gestation period. We investigated the clinical significance of eosinophilia in premature infants born at <34 weeks gestation. Methods: We analyzed the medical records of premature infants born at <34 weeks gestation who were admitted to the neonatal intensive care unit at Ewha Womans University Mokdong Hospital between January 2003 and September 2010. Eosinophilia was defined as an eosinophil percentage of >3% of the total leukocytes. Perinatal parameters and clinical parameters were also analyzed. Results: Of the 261 infants born at <34 weeks gestation, 22.4% demonstrated eosinophilia at birth. The eosinophil percentage peaked in the fourth postnatal week at 7.5%. The incidence of severe eosinophilia increased after birth up to the fourth postnatal week when 8.8% of all patients had severe eosinophilia. Severity of eosinophilia was positively correlated with a lower gestational age, birth weight, and Apgar score. Respiratory distress syndrome, bronchopulmonary dysplasia, nephrocalcinosis, intraventricular hemorrhage, and sepsis were associated with a higher eosinophil percentage. The eosinophil percentage was significantly higher in infants with bronchopulmonary dysplasia from the first postnatal week and the percentage was the highest in the fourth postnatal week, with the maximal difference being 4.1% (P<0.001). Conclusion: Eosinophilia is common in premature infants and reaches peak incidence and severity in the fourth postnatal week. The eosinophil percentage was significantly higher in bronchopulmonary dysplasia patients from the first postnatal week. Severe eosinophilia was significantly associated with the incidence of bronchopulmonary dysplasia even after adjusting for other variables.

• Neonatal Medicine
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• v.18 no.2
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• pp.177-181
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• 2011

Bronchopulmonary dysplasia (BPD) is characterized by arrest of vascular and alveolar development in premature infants. Recent advances in neonatology have increased the survival of immature babies. Consequently, the prevalence of BPD is increasing. Animal studies and autopsy findings of BPD have demonstrated interruption in vascular development and reversal of lung injury through promotion of vasculogenesis. Normal lung development is driven by temporal and spatial specific growth factors and cellto-cell signaling in vascular development. Lung injury through various pathways causes disruption in this complex interactive process and results in aberrant vascular development and subsequent BPD. By understanding the regulation of vascular growth of the lung, it would be possible to find new targets in the treatment and prevention of BPD in premature infants.

• Neonatal Medicine
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• v.18 no.2
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• pp.165-176
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• 2011

The pathologic hallmark of new bronchopulmonary dysplasia (BPD) is an arrest in alveolarization and vascular development. Alveoli are the fully mature gas-exchange units and alveolarization denotes the process through which the developing lung attains its fully mature structure. In human, alveolarization is mainly a postnatal event and begins in utero around 35 postmenstrual weeks and continues to 2 postnatal years. Beginning of respiration with very immature lungs as a result of preterm delivery renders the immature lung to be exposed to various injuries such as mechanical stretch, hyperoxia, infection/inflammation and leads to a disruption of normal alveolarization process, which is a main pathologic finding of BPD. Better understanding of the control mechanisms of normal alveolarization process should help us to figure out the pathophysiology of BPD and discover effective preventive or therapeutic measures for BPD. In this review, the pathologic evolution of BPD from 'old' to 'new' BPD, the detailed mechanisms of normal alveolarization, and the factors that disrupt normal alveolarization will be discussed.

• Neonatal Medicine
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• v.25 no.3
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• pp.91-95
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• 2018

Bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) is increasingly being recognized as a cause of morbidity and mortality in preterm infants. Recently, BPD-PH has also been shown to have additional long-term negative effects on neurodevelopmental outcomes and right ventricular function. Several significant risk factors associated with the development of BPD-PH have been identified. A screening strategy for BPD-PH is needed for infants presenting more than one risk factor. In addition, an early echocardiogram within 14 days of age may be a useful tool to identify infants at high-risk for BPD-PH. We have reviewed recent progress in research concerning clinical characteristics, presentation, and outcomes of BPD-PH and have suggested direction for future studies.

• Clinical and Experimental Pediatrics
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• v.53 no.6
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• pp.688-693
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• 2010

An increase in the number of preterm infants and a decrease in the gestational age at birth have resulted in an increase in the number of patients with significant bronchopulmonary dysplasia (BPD) and secondary pulmonary hypertension (PH). PH contributes significantly to the high morbidity and mortality in the BPD patients. Therefore, regular monitoring for PH by using echocardiography and B-type natriuretic peptide (BNP) or N-terminal-proBNP must be conducted in the BPD patients with greater than moderate degree to prevent PH and to ensure early treatment if PH is present. In the BPD patients with significant PH, multi-modality treatment, including treatment for correcting an underlying disease, oxygen supply, use of diverse selective pulmonary vasodilators (inhaled nitric oxide, inhaled prostacyclins, sildenafil, and endothelin-receptor antagonist) and other methods, is mandatory.

• Clinical and Experimental Pediatrics
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• v.60 no.7
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• pp.203-207
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• 2017

Chorioamnionitis is an inflammation in the fetal membranes or placenta. When chorioamnionitis develops, fetal lungs are exposed to inflammatory cytokines and mediators via amniotic fluid. Because inflammation plays a pivotal role in the development of bronchopulmonary dysplasia (BPD), a chronic lung disease of prematurity, fetal lung inflammation induced by chorioamnionitis has been considered to be one of the major pathogenetic factors for BPD. Although there have been a number of studies that demonstrated the relationship between chorioamnionitis and BPD, there are still controversies on this issue. The controversies on the relationship between chorioamnionitis and BPD arise from not-unified definitions of chorioamnionitis and BPD, different study populations, and the proportion of contribution between inflammation and infectious microorganisms. The publication bias also contributes to the controversies. Clinical trials targeting chorioamnionitis or microorganisms that cause chorioamnionitis will answer on the actual relationship between chorioamnionitis and BPD and provide a novel prophylactic strategy against BPD based on that relationship.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.44-49
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• 2009

Purpose : Early surfactant treatment and minimal ventilation, bronchopulmonary dysplasia needed prolonged oxygen supplement is a problem. This study aimed to report the effects of early surfactant treatment and minimal ventilation on the prevention of bronchopulmonary dysplasia in respiratory distress syndrome. Methods : We retrospectively studied 139 premature newborn infants (gestational age, 36 weeks; birth weight, 1,500 gm) admitted to the neonatal intensive care unit of Daegu Fatima Hospital between January 2001 and December 2006. We analyzed the occurrence of bronchopulmonary dysplasia with respect to ventilator care and surfactant treatment. Results : The incidence of bronchopulmonary dysplasia was significantly higher with prolonged ventilator care, moderate to severe respiratory distress syndrome, and low Apgar score (P<0.001). Despite early surfactant treatment and minimal ventilation, mild bronchopulmonary dysplasia occurs in a considerable number of patients with mild respiratory distress syndrome. The patient group with low Apgar scores required ventilator care for a prolonged period (P=0.020). Conclusion : Early surfactant treatment and minimal ventilation shortens the duration of ventilator care; however, the preventive effects on bronchopulmonary dysplasia are limited. Therefore, not only early surfactant treatment and minimal ventilation but also appropriate management in the delivery room is essential.