Current Status and Associated Factors of Post-Hemorrhagic Hydrocephalus in Infants of 22 to 28 Weeks Gestation With Severe Intraventricular Hemorrhage in Korea: A Nationwide Cohort Study

BACKGROUND

Post-hemorrhagic hydrocephalus (PHH), a common complication of severe intraventricular hemorrhage (IVH) in very low birth weight (BW) infants, is associated with significant morbidity and poor neurological outcomes. The objective of this study was to assess the current status of PHH and analyze the risk factors associated with the necessity of treatment for PHH in infants born between 22 and 28 weeks of gestation, specifically those with severe IVH (grade 3 or 4).

METHODS

The analysis was conducted on 1,097 infants who were born between 22-28 gestational weeks and diagnosed with severe IVH, using data from the Korean Neonatal Network. We observed that the prevalence of PHH requiring treatment was 46.3% in infants with severe IVH.

RESULTS

Higher rates of mortality, transfer during admission, cerebral palsy, and ventriculoperitoneal shunt after discharge were higher in infants with PHH than in those without PHH. PHH in severe IVH was associated with a higher rate of pulmonary hemorrhage, seizures, and IVH grade 4 in the entire cohort. In addition, it was associated with a lower rate of small for gestational age and chorioamnionitis. In the subgroup analysis, high BW, outborn status, pulmonary hemorrhage, seizure, sepsis, and IVH grade 4 were associated with a higher incidence of PHH between 22 and 25 gestational weeks (GW). In infants born between 26 and 28 GW, a higher incidence of PHH was associated with seizures and IVH grade 4.

CONCLUSION

It is necessary to maintain meticulous monitoring and neurological intervention for infants with PHH not only during admission but also after discharge. In addition, identifying the clinical factors that increase the likelihood of developing PHH from severe IVH is crucial.

Long-term impact of late pulmonary hypertension requiring medication in extremely preterm infants with severe bronchopulmonary dysplasia

This study investigated whether late pulmonary hypertension (LPH) independently increases the risk of long-term mortality or neurodevelopmental delay (NDD) in extremely preterm infants (EPIs) with severe bronchopulmonary dysplasia (BPD). Using prospectively collected data from the Korean Neonatal Network, we included EPIs with severe BPD born at 22-27 weeks' gestation between 2013 and 2021. EPIs having severe BPD with LPH (LPH, n = 124) were matched 1:3 with those without pulmonary hypertension (PH) as controls (CON, n = 372), via propensity score matching. LPH was defined as PH with the initiation of medication after 36 weeks' corrected age (CA). Long-term mortality after 36 weeks' CA or NDD at 18-24 months' CA was analyzed. NDD was assessed using composite scores based on various neurodevelopmental assessment modalities. LPH had significantly higher long-term mortality or NDD (45.2% vs. 23.1%, P < 0.001), mortality (24.2% vs. 4.84%, P < 0.001), and NDD (68.4% vs. 37.8%, P = 0.001), respectively than CON, even after adjusting for different demographic factors. Multivariable regression demonstrated that LPH independently increased the risk of mortality or NDD (adjusted odds ratio, 1.95; 95% confidence intervals, 1.17-3.25). When LPH occurs in EPIs with severe BPD, special monitoring and meticulous care for long-term survival and neurodevelopment are continuously needed.

Contemporary fluid management, humidity, and patent ductus arteriosus management strategy for premature infants among 336 hospitals in Asia

Objectives

The management of patent ductus arteriosus (PDA) is a critical concern in premature infants, and different hospitals may have varying treatment policies, fluid management strategies, and incubator humidity. The Asian Neonatal Network Collaboration (AsianNeo) collected data on prematurity care details from hospitals across Asian countries. The aim of this study was to provide a survey of the current practices in the management of PDA in premature infants in Asian countries.

Methods

AsianNeo performed a cross-sectional international questionnaire survey in 2022 to assess the human and physical resources of hospitals and clinical management of very preterm infants. The survey covered various aspects of hospitals resources and clinical management, and data were collected from 337 hospitals across Asia. The data collected were used to compare hospitals resources and clinical management of preterm infants between areas and economic status.

Results

The policy of PDA management for preterm infants varied across Asian countries in AsianNeo. Hospitals in Northeast Asia were more likely to perform PDA ligation (p < 0.001) than hospitals in Southeast Asia. Hospitals in Northeast Asia had stricter fluid restrictions in the first 24 h after birth for infants born at <29 weeks gestation (p < 0.001) and on day 14 after birth for infants born at <29 weeks gestation (p < 0.001) compared to hospitals in Southeast Asia. Hospitals in Northeast Asia also had a more humidified environment for infants born between 24 weeks gestation and 25 weeks gestation in the first 72 h after birth (p < 0.001). A logistic regression model predicted that hospitals were more likely to perform PDA ligation for PDA when the hospitals had a stricter fluid planning on day 14 after birth [Odds ratio (OR) of 1.70, p = 0.048], more incubator humidity settings (<80% vs. 80%-89%, OR of 3.35, p = 0.012 and <80% vs. 90%-100%, OR of 5.31, p < 0.001).

Conclusions

In advanced economies and Northeast Asia, neonatologists tend to adopt a more conservative approach towards fluid management, maintain higher incubator humidity settings and inclined to perform surgical ligation for PDA.

The effect of minimizing central line days for very low birth weight infants through quality improvement

Blood culture proven sepsis is associated with increased mortality and morbidity. Given the extended hospitalization of very preterm infants, catheter-related blood stream infections (CRBSIs) play a substantial role in sepsis. The reported incidence of CRBSIs in neonates varies from 3.2 to 21.8 CRBSIs per 1000 catheter line days. Moreover, discrepancies in neonatal practices and potential neglect may lead to the unwarranted prolongation of central lines. This study aims to compare two distinct periods (Pre-QI vs. Post-QI) in relation to the central line insertion rate and duration, as well as blood culture proven sepsis, duration of total parenteral nutrition (TPN), and the progression of feeding. These factors are known to be associated with prolonged hospitalization and increased morbidities. A total of 210 very low birth weight infants (VLBWIs), defined as either less than 32 weeks of gestational age (GA) or weighing less than 1500 g, were admitted to the Neonatal Intensive Care Unit (NICU) at Seoul St. Mary's Hospital, The Catholic University of Korea, between January 2020 and June 2023. Fourteen infants were excluded from the study as they did not survive beyond 1 month of life, and one was excluded due to a congenital anomaly. Consequently, the analysis included 195 VLBWIs. The Quality Improvement (QI) initiative began in January 2022, marking the division into two distinct epochs: the Pre-QI period, encompassing the years 2020 to 2021, and the Post-QI period, spanning from 2022 to 2023. The primary outcome measures included PICC insertion rates, duration, and feeding advancement or feeding-related complications. The hospital outcome measures were also compared between the two periods. A total of 195 VLBWI were included in the analysis. The birth weight was significantly lower in the pre-QI period, with an average of 1023 g compared to 1218 g (P < 0.001). Severe BPD ≥ moderate was significantly lower in the post-QI period (36.2% vs. 53.9%) (P < 0.001) along with shorter mechanical ventilation days (12 ± 29 vs. 22 ± 27) (P = 0.046). The PICC insertion rate was significantly decreased from 95.6% in pre-QI period compared to 55.2% in post-QI period (P < 0.001) along with a notable reduction in blood culture-proven sepsis (25.6% vs. 10.5%, P = 0.008). CRBSI rate was reduced from 1.3 to 1.1 per 1000 catheter days in the post-QI period. Moreover, the time required to achieve full enteral feeding of 100 mL/kg/day was significantly shorter in the post-QI (24 ± 23 vs. 33 ± 25) (P = 0.006). Multivariable logistic regression analysis for sepsis revealed that both birth weight and pre/post QI consistently demonstrated an association with lower sepsis rates in the Post-QI period. QI has the potential to reduce the burden of unnecessary interventions and blood culture proven sepsis rate along with CRBSI rate, thereby, optimizing the better care of very preterm babies.

Nationwide Long-Term Growth and Developmental Outcomes of Infants for Congenital Anomalies in the Digestive System and Abdominal Wall Defects With Surgery in Korea

BACKGROUND

Infants with congenital anomalies of the digestive system and abdominal wall defects requiring surgery are at risk of growth and developmental delays. The aim of this study was to analyze long-term growth and developmental outcomes for infants with congenital anomalies of the digestive system and abdominal wall defects who underwent surgery in Korea.

METHODS

We extracted data from the Korean National Health Insurance Service database for the years 2013-2019. Major congenital anomalies were defined according to the International Classification of Diseases-10 and surgery insurance claim codes. The χ² test and the Cochran-Armitage trend test were performed for data analysis.

RESULTS

A total of 4,574 infants with major congenital anomalies in the digestive system and abodminal wall defects, who had undergone surgey, were reviewed. Anorectal obstruction/stenosis was the most prevalent anomaly (4.9 per 10,000 live births). The prevalence of congenital anomalies of the digestive system was 15.5 per 10,000 live births, and that of abdominal wall defects was 1.5 per 10,000 live births. Seven percent of infants with congenital anomalies in the digestive system died, of which those with diaphragmatic hernia had the highest mortality rate (18.8%). Among 12,336 examinations at 6, 12, 24, 36, 48, 60, and 72 months of age, 16.7% showed a weight below the 10th percentile, 15.8% had a height below the 10th percentile, and 13.2% had a head circumference below the 10th percentile. Abnormal developmental screening results were observed in 23.0% of infants. Infants with esophageal atresia with/without tracheoesophageal fistula most often had poor growth and development. Delayed development and cerebral palsy were observed in 490 (10.7%) and 130 (2.8%) infants respectively. Comparing the results of infants born in 2013 between their 24- and 72-month health examinations, the proportions of infants with poor height and head circumference growth increased by 6.5% and 5.3%, respectively, whereas those with poor weight growth and abnormal developmental results did not markedly change between the two examinations.

CONCLUSION

Infants with congenital anomalies of the digestive system and abdominal wall defects exhibit poor growth and developmental outcomes until 72 months of age. Close monitoring and careful consideration of their growth and development after discharge are required.

Antenatal Magnesium Sulfate Is Not Associated With Improved Long-Term Neurodevelopment and Growth in Very Low Birth Weight Infants

BACKGROUND

Though antenatal magnesium sulfate (MgSO4) is widely used for fetal neuroprotection, suspicions about the long-term neuroprotection of antenatal MgSO4 have been raised.

METHODS

We investigated short- and long-term outcomes of antenatal MgSO4 use for 468 infants weighing < 1,500 g with a gestational age of 24-31 weeks.

RESULTS

Short-term morbidities and the risk of developmental delay, hearing loss, and cerebral palsy at a corrected age of 18-24 months and 3 years of age did not decrease in the MgSO4 group (infants who were exposed to MgSO4 for any purpose) or neuroprotection group (infants who were exposed to MgSO4 for fetal neuroprotection) compared with the control group (infants who were not exposed to MgSO4). The z-scores of weight, height, and head circumference did not increase in the MgSO4 group or neuroprotection group compared with the control group.

CONCLUSION

Antenatal MgSO4 including MgSO4 for neuroprotection did not have beneficial effects on long-term neurodevelopmental and growth outcomes.

Mesenchymal Stromal Cells Primed by Toll-like Receptors 3 and 4 Enhanced Anti-Inflammatory Effects against LPS-Induced Macrophages via Extracellular Vesicles

Although it has been suggested that toll-like receptor (TLR) 3 and TLR4 activation alters mesenchymal stromal cells (MSCs)' immunoregulatory function as anti- or pro-inflammatory phenotypes, we have previously confirmed that TLR4-primed hUCB-MSCs alleviate lung inflammation and tissue injury in an E. coli-induced acute lung injury (ALI) mouse model. Therefore, we hypothesized that strong stimulation of TLR3 or TLR4 prompts hUCB-MSCs to exhibit an anti-inflammatory phenotype mediated by extracellular vesicles (EVs). In this study, we compared the anti-inflammatory effect of TLR3-primed and TLR4-primed hUCB-MSCs against an LPS-induced ALI in vitro model by treating MSCs, MSC-derived conditioned medium (CM), and MSC-derived extracellular vesicles (EVs). LPS-induced rat primary alveolar macrophage and RAW 264.7 cells were treated with naïve, TLR3-, and TLR4-primed MSCs and their derived CM and EVs. Flow cytometry and ELISA were used to evaluate M1-M2 polarization of macrophages and pro-inflammatory cytokine levels, respectively. LPS-stimulated macrophages showed significantly increased pro-inflammatory cytokines compared to those of the normal control, and the percentage of M2 macrophage phenotype was predominantly low. In reducing the inflammatory cytokines and enhancing M2 polarization, TLR3- and TLR4-primed MSCs were significantly more effective than the naïve MSCs, and this finding was also observed with the treatment of MSC-derived CMs and EVs. No significant difference between the efficacy of TLR3- and TLR-primed MSCs was observed. Strong stimulation of TLR3- and TLR4-stimulated hUCB-MSCs significantly reduced pro-inflammatory cytokine secretion from LPS-induced macrophages and significantly enhanced the M2 polarization of macrophages. We further confirmed that TLR-primed MSC-derived EVs can exert anti-inflammatory and immunosuppressive effects alone comparable to MSC treatment. We hereby suggest that in the LPS-induced macrophage in vitro model, EVs derived from both TLR3 and TLR4-primed MSCs can be a therapeutic candidate by promoting the M2 phenotype.

Loop-mediated isothermal amplification assay for screening congenital cytomegalovirus infection in newborns

Congenital cytomegalovirus (CMV) infection is a common cause of sensorineural hearing loss and neurodevelopmental impairment in newborns. However, congenital CMV infection cannot be diagnosed using samples collected more than 3 weeks after birth because testing after this time cannot distinguish between congenital infection and postnatal infection. Herein, we developed a robust loop-mediated isothermal amplification (LAMP) assay for the large-scale screening of newborns for congenital CMV infection. In contrast to conventional quantitative polymerase chain reaction (qPCR), which detects CMV within a dynamic range of 1.0 × 106 to 1.0 × 102 copies/μL, our quantitative LAMP assay (qLAMP) detects CMV within a dynamic range of 1.1 × 108 to 1.1 × 103 copies/μL. Moreover, the turnaround time for obtaining results following DNA extraction is 90 min in qPCR but only 15 min in qLamp. The colorimetric LAMP assay can also detect CMV down to 1.1 × 103 copies/μL within 30 min, irrespective of the type of heat source. Our LAMP assay can be utilized in central laboratories as an alternative to conventional qPCR for quantitative CMV detection, or for point-of-care testing in low-resource environments, such as developing countries, via colorimetric naked-eye detection. KEY POINTS: • LAMP assay enables large-scale screening of newborns for congenital CMV infection. • LAMP allows colorimetric or quantitative detection of congenital CMV infection. • LAMP assay can be used as a point-of-care testing tool in low-resource environments.

Five-year follow-up of phase II trial of stromal cells for bronchopulmonary dysplasia

BACKGROUND

We previously performed a phase II randomised double-blind clinical trial of mesenchymal stromal cell (MSCs) transplantation to prevent bronchopulmonary dysplasia in extremely premature infants. Subsequently, we followed the infants enrolled in this clinical trial to determine the safety and effectiveness of MSCs against bronchopulmonary dysplasia at 5-year follow-up.

METHODS

We evaluated infants at 5 years of age receiving placebo or MSCs in a prospective follow-up study.

RESULTS

In terms of the primary end point of composite respiratory morbidities, including respiratory problem-related readmission, emergency department visits or oxygen therapy, the MSC group had a rate of 60.7% for composite morbidities, while the control group showed a tendency of higher rate of 83.9% for the same outcomes without statistical significance. In terms of the secondary outcomes, the MSC group infants showed a tendency of being less likely to visit emergency department (control 67.7% vs MSC 35.7%) and to receive oxygen therapy (control 29.0% vs MSC 3.6%). No difference was observed in the incidence of respiratory problem-related hospital readmission or wheezing episodes between the groups.

CONCLUSION

Intratracheally instilled MSCs showed the possibility of potential to decrease respiratory symptom-related emergency department visits and oxygen therapy episodes in infants born extremely preterm during the 5 years after a phase II randomised controlled, double-blind trial of MSCs transplantation for bronchopulmonary dysplasia. This small size study suggests preliminary insights that can be further tested using larger sample sizes.

TRIAL REGISTRATION NUMBER

NCT01897987.

Optimal Protocols and Management of Clinical and Genomic Data Collection to Assist in the Early Diagnosis and Treatment of Multiple Congenital Anomalies

Standardized protocols have been designed and developed specifically for clinical information collection and obtaining trio genomic information from infants affected with congenital anomalies (CA) and their parents, as well as securing human biological resources. The protocols include clinical and genomic information collection on multiple CA that were difficult to diagnose using pre-existing screening methods. We obtained human-derived resources and genomic information from 138 cases, including 45 families of infants with CA and their parent trios. For the clinical information collection protocol, criteria for target patient selection and a consent system for collecting and utilizing research resources are crucial. Whole genome sequencing data were generated for all participants, and standardized protocols were developed for resource collection and manufacturing. We recorded the phenotype information according to the Human Phenotype Ontology term, and epidemiological information was collected through an environmental factor questionnaire. Updating and recording of clinical symptoms and genetic information that have been newly added or changed over time are significant. The protocols enabled long-term tracking by including the growth and development status that reflect the important characteristics of newborns. Using these clinical and genetic information collection protocols for CA, an essential platform for early genetic diagnosis and diagnostic research can be established, and new genetic diagnostic guidelines can be presented in the near future.

Major Congenital Anomalies in Korean Livebirths in 2013-2014: Based on the National Health Insurance Database

BACKGROUND

In Korea, there have been no reports comparing the prevalence of major congenital anomalies with other countries and no reports on surgical treatment and long-term mortality. We investigated the prevalence of 67 major congenital anomalies in Korea and compared the prevalence with that of the European network of population-based registries for the epidemiological surveillance of congenital anomalies (EUROCAT). We also investigated the mortality and age at death, the proportion of preterm births, and the surgical rate for the 67 major congenital anomalies.

METHODS

Korean National Health Insurance claim data were obtained for neonates born in 2013-2014 and admitted within one-year-old. Sixty-seven major congenital anomalies were defined by medical diagnoses classified by International Classification of Diseases-10 codes according to the EUROCAT definition version 2014. Mortality and surgery were defined if any death or surgery claim code was confirmed until 2020. Poisson distribution was used to calculate the 95% confidence interval of the congenital anomaly prevalence.

RESULTS

The total prevalence of the 67 major anomalies was 433.5/10,000 livebirths. When compared with the prevalence of each major anomaly in EUROCAT, the prevalence of spina bifida, atrial septal defect (ASD), congenital megacolon, hip dislocation and/or dysplasia and skeletal dysplasia were more than five times higher in Korea. In contrast, the prevalence of aortic atresia/interrupted aortic arch and gastroschisis was less than one-fifth in Korea. The proportion of preterm births was 15.7%; however, more than 40% of infants with anencephaly, annular pancreas and gastroschisis were preterm infants. Additionally, 29.2% of the major anomalies were admitted to the neonatal intensive care units at birth, and 25.6% received surgical operation. The mortality rate was 1.7%, and 78.2% of the deaths occurred within the first year of life. However, in neonates with tricuspid valve atresia and stenosis, duodenal atresia or stenosis, and diaphragmatic hernia, more than half died within their first month of life. ASD and ventricular septal defect were the most common anomalies, and trisomy 18 and hypoplastic left heart syndrome were the most fatal anomalies. All infants with aortic atresia/interrupted aortic arch and conjoined twins received surgery.

CONCLUSION

The proportion of surgeries, preterm births and mortality was high in infants with major congenital anomalies. The establishment of a national registry of congenital anomalies and systematic support by national medical policies are needed for infants with major congenital anomalies in Korea.

Variations in medical practice of retinopathy of prematurity among 8 Asian countries from an international survey

Advances in perinatal care have led to the increased survival of preterm infants with subsequent neonatal morbidities, such as retinopathy of prematurity (ROP). This study aims to compare the differences of neonatal healthcare systems, resources, and clinical practice concerning ROP in Asia with review of current literature. An on-line survey at the institutional level was sent to the directors of 336 neonatal intensive care units (NICU) in 8 collaborating national neonatal networks through the Asian Neonatal Network Collaboration (AsianNeo). ROP screening was performed in infants born at < 34 weeks in Indonesia and Japan. In South Korea, Malaysia, and Taiwan, most screened for ROP in infants born at < 32 weeks. In all networks, majority of NICUs conducted ROP screening to infants with birth weight < 1500 g. In most NICU's in-hospital ophthalmologists performed indirect ophthalmoscopy and some were supplemented with digital imaging. Both laser photocoagulation and anti-vascular endothelial growth factor injection are performed for treatment and, vitreous surgeries are conducted less frequently in all countries. Despite limited information collected by the survey, this first study to compare ROP practices implemented in eight Asian countries through AsianNeo will enable an understanding of the differences and facilitate quality improvement by sharing better practices.

Changes to Blood-Sampling Protocol to Reduce the Sampling Amount in Neonatal Intensive Care Units: A Quality Improvement Project

(1) Background: This study aimed to evaluate whether the implementation of a modified blood-sampling protocol, which focused on need-based laboratory testing and minimized venous sampling by replacing it with point-of-care testing (POCT) via capillary puncture, successfully reduced iatrogenic blood loss, incidence of anemia, and the frequency of blood transfusion among extremely low-birth-weight infants (ELBWIs) without negatively affecting neonatal outcomes. (2) Methods: A retrospective analysis was conducted on 313 ELBWIs with a gestational age (GA) of between 23 and 28 weeks and born between 2013 and 2019. The infants were divided into two groups corresponding to the periods before (period I) and after (period II) the implementation of the modified blood-sampling protocol in January 2016. Propensity score matching was conducted to minimize selection bias. Clinical data, including the frequency and amount of blood sampling, the frequency and volume of blood transfusion, and clinical characteristics, such as gestational age, birth weight, and neonatal outcome data, were collected and compared between the two groups. (3) Results: No significant differences in GA or birth weight between the two periods were observed. The total sampling volume a month after birth (16.7 ± 4.1 mL vs. 15.6 ± 4.4 mL, p = 0.03) and the total sampling volume during hospitalization days (51.4 ± 29.7 mL vs. 44.3 ± 27.5 mL, p = 0.04) in period II were significantly lower than those in period I. There were no differences in terms of anemia (hemoglobin 10.8 ± 2.2 vs. 11.0 ± 1.9, p = 0.43) and mortality or morbidity, such as intraventricular hemorrhage, retinopathy of prematurity, bronchopulmonary dysplasia, necrotizing enterocolitis, and sepsis, between the two periods. Although the transfusion frequency and amount did not present significant differences between the periods, we observed a positive correlation between the transfusion frequency and sampling volume (coefficient: 0.09, 95% CI: 0.08-0.11). (4) Conclusions: The modified blood-sampling protocol effectively reduced the level of iatrogenic blood loss without negatively affecting the neonatal outcomes.

The Multifaceted Clinical Characteristics of Congenital Cytomegalovirus Infection: From Pregnancy to Long-Term Outcomes

BACKGROUND

The aim of this study was to capture multifaceted clinical characteristics of congenital cytomegalovirus (CMV) infection from diagnosis to treatment using a multidisciplinary approach including obstetrics, pediatrics, pathology, and otorhinolaryngology-head and neck surgery.

METHODS

This is a retrospective study including 30 consecutive cases of congenital CMV infection that were diagnosed at a single tertiary hospital located in Seoul, Korea from January 2009 to December 2020. Congenital CMV infection was defined as a positive result by polymerase chain reaction from urine, saliva or cerebrospinal fluid or positive CMV IgM from neonatal blood sampled within 3 weeks after birth. All cases were analyzed with respect to whole clinical characteristics from diagnosis to treatment of congenital CMV by a multidisciplinary approach including prenatal sonographic findings, maternal immune status regarding CMV infection, detailed placental pathology, neonatal clinical manifestation, auditory brainstem response test, and antiviral treatment (ganciclovir or valganciclovir). Long-term outcomes including developmental delay and hearing loss were also investigated.

RESULTS

The total number of births during the study period in our institution was 19,385, with the prevalence of congenital infection estimated to be 0.15%. Among 30 cases of congenital CMV, the median gestational age at delivery was 32.2 weeks [range, 22.6-40.0] and 66.7% of these infants were delivered preterm at less than 37 weeks. Suspected fetal growth restriction was the most common prenatal ultrasound finding (50%) followed by ventriculomegaly (17.9%) and abnormal placenta (17.9%), defined as thick placenta with calcification. No abnormal findings on ultrasound examination were observed in one-third of births. Maternal CMV serology tests were conducted in only 8 cases, and one case each of positive and equivocal IgM were found. The most common placental pathologic findings were chronic villitis (66.7%) and calcification (63.0%), whereas viral inclusions were identified in only 22.2%. The most common neonatal manifestations were jaundice (58.6%) followed by elevation of aspartate aminotransferase (55.2%) and thrombocytopenia (51.7%). After excluding cases for which long-term outcomes were unavailable due to death (n = 4) or subsequent follow up loss (n = 3), developmental delay was confirmed in 43.5% of infants (10/23), and hearing loss was confirmed in 42.9% (9/21) during the follow-up period. In our cohort, 56.7% (17/30) of neonates were treated for congenital CMV with ganciclovir or valganciclovir.

CONCLUSION

Our data show that prenatal findings including maternal serologic tests and ultrasound have limited ability to detect congenital CMV in Korea. Given that CMV is associated with high rates of developmental delay and hearing loss in infants, there is an urgent need to develop specific strategies for the definite diagnosis of congenital CMV infection during the perinatal period by a multidisciplinary approach to decrease the risks of neurologic impairment and hearing loss through early antiviral treatment.

SOCS3 Protein Mediates the Therapeutic Efficacy of Mesenchymal Stem Cells against Acute Lung Injury

Mesenchymal stem cells (MSCs) have been studied as novel therapeutic agents because of their immunomodulatory properties in inflammatory diseases. The suppressor of cytokine signaling (SOCS) proteins are key regulators of the immune response and macrophage modulation. In the present study, we hypothesized that SOCS in MCSs might mediate macrophage modulation and tested this in a bacteria-induced acute lung injury (ALI) mouse model. The macrophage phenotype was observed in RAW264.7 alveolar macrophages exposed to lipopolysaccharide (LPS) in an in vitro model, and in the ALI mouse model induced by tracheal administration of Escherichia coli (1 × 10⁷ CFU in 0.05mL PBS). In LPS-exposed RAW264.7 cells, the levels of markers of M1 macrophages, such as CD86 and pro-inflammatory cytokines (IL-1α, IL-1β, IL-6 and TNF-α), significantly increased, but they significantly reduced after MSC treatment. Meanwhile, the levels of markers of M2 macrophages, such as CD204 and anti-inflammatory cytokines (IL-4 and IL-10), increased after LPS exposure, and further significantly increased after MSC treatment. This regulatory effect of MSCs on M1/M2 macrophage polarization was significantly abolished by SOCS3 inhibition. In the E. coli-induced ALI model, tissue injury and inflammation in the mouse lung were significantly attenuated by the transplantation of MSCs, but not by SOCS3-inhibited MSCs. The regulatory effect of MSCs on M1/M2 macrophage polarization was observed in the lung injury model but was significantly abolished by SOCS3 inhibition. Taken together, our findings suggest that SOCS3 is an important mediator for macrophage modulation in anti-inflammatory properties of MSCs.

Microbiologic Epidemiology of Early-onset Sepsis in Neonates Born at ≥35 0/7 Weeks' Gestation in Korea During 2009-2018

BACKGROUND

Sepsis within the first 3 days of life remains a leading cause of neonatal mortality and morbidity. However, few studies have addressed the epidemiology of sepsis in late preterm and term neonates, particularly in Asia. We aimed to estimate the epidemiology of early-onset sepsis (EOS) in neonates born at ≥35 0/7 weeks' gestation in Korea.

METHODS

A retrospective study was conducted in neonates with proven EOS born at ≥35 0/7 weeks' gestation from 2009 to 2018 at seven university hospitals. EOS was defined as identifying bacteria from a blood culture within 72 hours after birth.

RESULTS

A total of 51 neonates (0.36/1,000 live births) with EOS were identified. The median duration from birth to the first positive blood culture collection was 17 hours (range, 0.2-63.9). Among the 51 neonates, 32 (63%) patients were born by vaginal delivery. The median Apgar score was 8 (range, 2-9) at 1 minute and 9 (range, 4-10) at 5 minutes. The most common pathogen was group B Streptococcus (n = 21; 41.2%), followed by coagulase-negative staphylococci (n = 7; 13.7%) and Staphylococcus aureus (n = 5, 9.8%). Forty-six (90.2%) neonates were treated with antibiotics on the first day of symptom onset, and 34 (73.9%) neonates received susceptible antibiotics. The overall 14-day case-fatality rate was 11.8%.

CONCLUSION

This is the first multicenter study on the epidemiology of proven EOS in neonates born at ≥35 0/7 weeks' gestation and found that group B Streptococcus was the most common pathogen in Korea.

Stem cells for neonatal brain injury - Lessons from the bench

Neonatal brain injury resulting from various intractable disorders including intraventricular hemorrhage and hypoxic ischemic encephalopathy still remains a major cause of mortality and morbidities with few effective treatments. Recent preclinical research results showing the pleiotropic neuroprotective effects of stem cell therapy, specifically mesenchymal stem cells (MSCs), suggest that MSCs transplantation might be a promising new therapeutic modality for neuroprotection against the currently intractable and devastating neonatal brain injury with complex multifactorial etiology. This review summarizes recent advances in preclinical stem cell research for treating neonatal brain injury with a focus on the important issues including the mechanism of neuroprotection, and determining the ideal cell source, route, timing and dose of MSCs transplantation.

Comprehensive Evaluation of the NeoBase 2 Non-derivatized MSMS Assay and Exploration of Analytes With Significantly Different Concentrations Between Term and Preterm Neonates

Background

Despite the popularity of the NeoBase 2 Non-derivatized MSMS assay (PerkinElmer, Turku, Finland), there are no reports of its comprehensive evaluation, including the ability to distinguish transient tyrosinemia of the newborn (TTN) from tyrosinemia type 1 (TYR 1) using succinylacetone (SUAC). No newborn screening (NBS) cutoffs for preterm neonates in the Korean population have been suggested. We evaluated the NeoBase 2 assay and identified analytes requiring different cutoffs in preterm neonates.

Methods

Residual NBS dried blood spot samples and proficiency testing (PT) materials of the Newborn Screening Quality Assurance Program and the Korean Association of External Quality Assessment Service were used. Precision, accuracy, limit of detection (LOD), lower limit of quantification (LLOQ), linearity, recovery, carryover, and performance of SUAC were evaluated. Cutoffs were determined, and analytes requiring different cutoffs in preterm neonates were investigated.

Results

Mean CVs for within-run and between-day precision were within 15%. Accuracy analysis indicated high agreement with in-house derivatized assay results and results of other PT participants. All analytes demonstrated acceptable LOD, LLOQ, and linearity. Recoveries were acceptable, except for SUAC. Carryover was negligible. Cutoffs were established for all analytes; Tyr, adenosine, and C20:0-lysophosphatidylcholine required different cutoffs in preterm neonates. Differential diagnosis of TYR 1 and TTN was successful with simultaneous Tyr and SUAC measurement.

Conclusions

The NeoBase 2 assay demonstrated satisfactory performance. The additional analytes provide a wider diagnostic coverage, and the simultaneous measurement of Tyr and SUAC is efficient in excluding TYR 1. The new cutoffs for preterm neonates may decrease false-positive rates, without compromising diagnostic sensitivity.

On the 10th Anniversary of the Korean Neonatal Network

The Korean Neonatal Network (KNN), which is celebrating its 10th anniversary, currently has more than 100 staff and researchers from >70 neonatal intensive care units nationwide in Korea. More than 85% to 90% of the population of very low birth weight infants in Korea are registered yearly, and more than half are followed up for up to 3 years at the KNN. A total of >19,000 cases have been accumulated through a strict data quality management process of the KNN. Based on this, >100 research projects have been proposed, >70 peer-reviewed papers have been published in leading international journals, and the cornerstone of the quality improvement project has been launched. In addition, we recently expanded the number of subjects for registration to very premature infants <32 weeks of age and continue to provide essential evidence data for establishing national health policies, such as linking with government policy projects of the Ministry of Health and Welfare for preterm infants. In such manner, the KNN is confident to be successfully and actively moving toward reaching the ultimate goal of standardizing neonatal intensive care and management of preterm infants in Korea by providing essential data for national health policy establishment along with quality improvement through evidence-based interactive data.

The Prevalence of Symptomatic Congenital Cytomegalovirus Disease in Korea; A 15-Year Multicenter Study and Analysis of Big Data From National Health Insurance System

The birth prevalence of symptomatic congenital cytomegalovirus (cCMV) disease among live birth in Korea from a multicenter study was 0.06% during 2001-2015 with increasing frequency. The administrative prevalence of cCMV infection by big-data analysis from the national health insurance system was 0.01% and the average healthcare cost was US$2010 per person.

Impact of time to full enteral feeding on long-term neurodevelopment without mediating by postnatal growth failure in very-low-birth-weight-infants

This study aimed to determine if time to achieve full enteral feeding (TFF) directly impacted long-term neurodevelopmental delay (NDD) and whether long-term postnatal growth failure (PGF) was a mediator of this association in very-low-birth-weight (VLBW) infants. Using prospectively collected cohort data from the Korean Neonatal Network, we included eligible VLBW infants who achieved TFF at least once and classified enrolled infants into four groups using exposure severity (P1 to P4 as TFF < 16, 16-30, 31-45, and > 45 postnatal days, respectively). After adjusting for confounding variables, survival without NDD was significantly decreased in P4 infants compared with that in P2 infants. P1 infants had a lower risk of weight and height PGF than P2 infants; however, P4 infants had higher risks of height and head circumference PGF than P2 infants. Weight and height PGF were significantly associated with an increased risk of NDD. In mediation analysis, early and delayed TFF revealed direct positive and negative impacts, respectively, on the risk of NDD without mediation by PGF. TFF impacted survival without NDD, and PGF did not mediate this association in VLBW infants. Additionally, these results can be translated into evidence-based quality improvement practice.

Neonatal Intensive Care Quality Level-Dependent Variations in the Survival Rate of Infants with a Birth Weight of 500 g or Less in Korea: A Nationwide Cohort Study

OBJECTIVE

Recent evidence suggests that the survival of peri-viable infants with birth weight (BW) ≤500 g could be improved with better care practices in the neonatal intensive care unit (NICU). This study aimed to investigate the care quality level of NICU-dependent variations in the survival rate of infants with BW ≤500 g.

METHODS

To determine the quality of NICU care-dependent variations in the survival rate, 226 eligible infants of BW ≤500 g and ≥22 weeks gestation registered in the Korean Neonatal Network between 2013 and 2017 were grouped according to the survival rates of infants at 23-24 weeks gestation, reflecting the care quality level of each NICU as group I (≥50%, n = 107) and group II (<50%, n = 119).

RESULTS

The survival rate of group I infants (40.2%, 43/107) was significantly higher than that of group II infants (14.3%, 17/119). Significantly reduced deaths from birth to the age of 7 days due to cardiorespiratory causes were the primary contributors to improved survival. In multivariable Cox hazard model analyses, besides the gestational age and BW, antenatal steroid use, cesarean section, pH, and base excess at admission were associated with improved infant survival.

CONCLUSIONS

The survival rate of pre-viable infants with BW ≤500 g could be improved by providing better NICU quality care practices, including better cardiorespiratory management starting from delivery room resuscitation.

Early Discontinuation of Levothyroxine Treatment Is Safe and Feasible in Extremely Low Birth Weight Infants with Delayed Hyperthyrotropinemia

BACKGROUND

While recent pieces of evidence suggest that discontinuation of levothyroxine replacement therapy (LRT) earlier than the current guidelines of 3 years is possible, the optimal duration of LRT for delayed hyperthyrotropinemia in extremely low birth weight infants (ELBWIs) remains unknown.

OBJECTIVE

This study aimed to investigate the feasibility of early discontinuation of LRT for delayed hyperthyrotropinemia in ELBWIs.

METHODS

The medical records of 92 ELBWIs who had shown delayed hyperthyrotropinemia, defined as a delayed rise in thyroid-stimulating hormone (TSH) levels to >20 µIU/mL after initial normal TSH level, were retrospectively reviewed to determine whether the duration of LRT affects the short-term outcomes at discharge from neonatal intensive care unit (NICU) and the long-term outcomes at the corrected age (CA) of 2 years. The infants were grouped into: no LRT required group (n = 21), short-term LRT given until the time of NICU discharge - 90 ± 64 (13-211) days group (n = 36), and long-term LRT given - 749 ± 333 (339-1,967) days group (n = 35).

RESULTS

While mortality in the no LRT required group was significantly higher than that in the long-term LRT group, no significant differences were observed in short-term outcomes at discharge from NICU and long-term growth and neurodevelopmental outcomes at CA of 2 years between the short- and long-term LRT groups.

CONCLUSIONS

Termination of LRT at around the time of discharge from NICU in well, clinically stable ELBWIs who have delayed hyperthyrotropinemia appears to be safe and feasible and avoids the risk of overtreatment.

Association Between Retinopathy of Prematurity in Very-Low-Birth-Weight Infants and Neurodevelopmental Impairment

PURPOSE

To evaluate the impact of retinopathy of prematurity (ROP) severity and the treatment of very-low-birth-weight infants (VLBWIs) on neurodevelopmental impairment in early childhood.

DESIGN

Prospective cohort study.

METHOD

This was a prospective cohort study. The data were obtained from the Korean Neonatal Network (KNN), a nationwide registry for VLBWIs. Infants who were born from 2013 to 2015 and underwent ROP evaluation at birth and neurodevelopmental examinations at corrected ages of 18 to 24 months were included in the study. Infants with a history of meningitis or severe congenital anomalies were excluded. The VLBWI patients were grouped into no ROP, no treatment-requiring ROP (non-TR-ROP), and treatment-requiring ROP (TR-ROP) groups. Neurodevelopmental impairment was defined as participants who had at least 1 developmental problem according to the Bayley Scales of Infant and Toddler Development-2nd Edition (Bayley-II; <70), Bayley Scales of Infant and Toddler Development-3rd Edition (Bayley-III; <70), and Korean Developmental Screening Test (K-DST) tests (below -1 SD), and the Korean Ages and Stages Questionnaire (K-ASQ) (below the threshold) and Gross Motor Function Classification System (GMFCS; at level 2 or above). Multivariable logistic regression analysis was performed to evaluate the association between ROP and neurodevelopmental impairment.

RESULT

Among 3132 infants, 1093 (34.9%) had ROP. Among the ROP infants, 644 were not treated for ROP (non-TR-ROP group) and 449 received ROP treatments (TR-ROP group). The patients in the TR-ROP group had an increased risk of developing neurodevelopmental problems compared to those in the no ROP group (odds ratio [OR] = 1.72, 95% CI = 1.33-2.21). The TR-ROP group had a higher risk of all 3 types of neurodevelopmental problems: mental (OR = 1.62, 95% CI = 1.25-2.09), social (OR = 1.62, 95% CI = 1.12-2.09), and motor (OR = 1.69, 95% CI = 1.31-2.18). The risk of neurodevelopmental problems in patients treated with laser therapy did not differ from that in patients treated with anti-vascular endothelial growth factor (anti-VEGF) therapy (OR = 1.17, 95% CI = 0.73-1.88).

CONCLUSION

ROP was independently associated with neurodevelopmental impairment in early childhood. The type of ROP treatment (anti-VEGF or laser treatment) did not affect neurodevelopmental impairment in patients in the TR-ROP group.

Comparison of definitions of bronchopulmonary dysplasia to reflect the long-term outcomes of extremely preterm infants

Survivors of neonatal bronchopulmonary dysplasia (BPD) have persistent respiratory, neurodevelopmental, and growth impairment over the first few years of life and later childhood, which represents an emerging burden for health systems. Therefore, there is an increasing need for a new definition and grading system of BPD that predicts long-term outcomes of high-risk infants who need timely and proper intervention to improve outcomes. We compared new definitions of BPD (National Institute of Child Health and Human Development [NICHD] 2018 and Neonatal Research Network [NRN] 2019) to the original NICHD 2001 definition at 3 years of age using a nationwide cohort of extreme preterm infants. New definitions and severity grading were clearly related to respiratory, neurodevelopmental, and growth impairments at 3 years of age and at 18-24 months corrected age (CA), whereas the original NICHD 2001 definition was not. Furthermore, the negative effect of BPD on growth was ameliorated at 3 years of age compared to 18-24 months CA. However, the negative effect of BPD in neonates on the respiratory system and neurodevelopment persisted at 3 years of age. These new definitions should be adopted to identify high-risk infants and improve long-term outcomes by exact diagnosis and BPD severity classification.

Mesenchymal Stem Cells and Formyl Peptide Receptor 2 Activity in Hyperoxia-Induced Lung Injury in Newborn Mice

Formyl peptide receptor (FPR) 2 is known to play a critical role in regulating inflammation, including either the pro-inflammatory or pro-resolving effects. However, its role in neonatal hyperoxia-induced lung injury has not been delineated. In this study, we investigate whether mesenchymal stem cells (MSCs) attenuate hyperoxia-induced neonatal lung injury by regulating FPR2 activity. We observed a significant increase in FPR2 levels in alveolar macrophages (RAW264.7 cells) after H2O2-induced stress, which decreased after MSC treatment. In the H2O2-induction model, increased levels of inflammatory cytokines (IL-1α and TNF-α) were significantly reduced in RAW264.7 cells after treatment with WRW4, an inhibitor of FPR2, or MSCs. Viability of lung epithelial cells and endothelial cells was significantly improved when cultured in the conditioned media of RAW264.7 cells treated with WRW4 or MSCs, compared to when cultured in the conditioned media of control RAW265.7 cells exposed to H2O2. For the in vivo study, wild-type and FPR2 knockout (FPR2-/-) C57/BL6 mouse pups were randomly exposed to 80% oxygen or room air from postnatal day (P) 1 to P14. At P5, 2 × 105 MSCs were transplanted intratracheally. MSCs reduced the elevated FPR2 activity at P7 and improved the decreased FPR2 activity as well as the increased immuno-stained FPR2 activity in alveolar macrophages in hyperoxic lungs at P14. Both FPR2-/- and MSCs similarly attenuated impaired alveolarization and angiogenesis, and increased apoptosis and inflammation of hyperoxic lungs without synergistic effects. Our findings suggest that the protective effects of MSCs in hyperoxic lung injury might be related to indirect modulation of FPR2 activity, at least of alveolar macrophages in neonatal mice.

Serial Long-Term Growth and Neurodevelopment of Very-Low-Birth-Weight Infants: 2022 Update on the Korean Neonatal Network

BACKGROUND

We aimed to evaluate the long-term growth and neurodevelopmental outcomes of very-low-birth-weight infants (VLBWIs, birth weight < 1,500 g) born between 2013, the establishment of the Korean Neonatal Network (KNN), and 2018, both at 18-24 months of corrected age and three years of age, using a nationwide large cohort, and to evaluate whether these outcomes have improved over time since 2013.

METHODS

This study used data from the annual reports of the KNN for 18-24 months of corrected age (follow-up 1) and three years of age (follow-up 2). Follow-up 1 data were collected from 10,065 eligible VLBWIs born between January 1, 2013, and December 31, 2018. Follow-up 2 data were collected from 8,156 eligible VLBWIs born between January 1, 2013, and December 31, 2017.

RESULTS

The overall follow-up rates of VLBWIs at follow-ups 1 and 2 were 74.6% (7,512/10,065) and 57.7% (4,702/8,156), respectively. The overall mortality rate between discharge from the neonatal intensive care unit and follow-up 1 was 1% (104/10,065). The overall mortality rate between follow-ups 1 and 2 was 0.049% (4/8,156). Growth restrictions decreased over time, especially weight growth restrictions, which significantly decreased according to era (17% in infants born in 2013-2014 and 13% in infants born in 2017-2018). Fewer infants were re-hospitalized and required rehabilitative support according to era at follow-up 1. More infants had language developmental delays and required language support according to era, both at follow-ups 1 and 2. The incidence of cerebral palsy has significantly decreased over time, from 6% in infants born in 2013-2014 to 4% in infants born in 2017-2018 at follow-up 1, and from 8% in infants born in 2013-2014 to 5% in infants born in 2017 at follow-up 2.

CONCLUSION

Long-term outcomes of VLBWIs regarding weight growth and cerebral palsy, the most common motor disability in childhood, have improved serially according to era since 2013. However, the rate of infants with language delays requiring language support has increased according to era. Further studies are required on the increased trends of language delay and language support while improving motor outcomes.

Postnatal women's breastfeeding beliefs, practices, and support during the COVID-19 pandemic: a cross-sectional comparative study across five countries

Background

Women with COVID-19 experienced numerous concerns and doubts about the safety of breastfeeding their babies, and lack of support may have impacted breastfeeding practices. This study aims to compare breastfeeding beliefs, practices, and contact with healthcare professionals regarding the level of postnatal feeding support provided during the COVID-19 pandemic in Brazil, South Korea, Taiwan, Thailand, and the United Kingdom.

Methods

A multi-country cross-sectional study was conducted with postnatal women in five countries. Women up to six months postpartum were invited to complete an online survey concerning the transmission of preventative measures, beliefs toward breastfeeding, infant feeding practices in the last 24 hours and experiences of postnatal infant feeding support between July to November 2021. Bivariate and multivariate analyses were performed to identify the association.

Results

Of the 3,253 eligible responses received, 39.5% of children were aged between one and two months, but in Taiwan (36%) and South Korea (42.8%) they were between three and four months. The mean of the belief score was significantly different among countries (p < 0.0001). Women in Brazil and the UK had a higher rate of breastfeeding at the breast (90.7% and 85.4%, respectively) compared to the three Asian countries (p < 0.0001) while feeding with expressed breastmilk in Thailand (59.9%), Taiwan (52.6%), and South Korea (50.4%) was higher than the others (p < 0.0001). Brazil and UK mothers (mean = 16.0 and 14.5 respectively) had a higher mean score for belief toward breastfeeding during the COVID-19 than the others. These results are inversely associated with breastfeeding but positively related to formula feeding practice. Postnatal feeding support during the COVID-19 pandemic was mainly provided by healthcare professionals (67.1%) and peers / family through face-to-face personal contact (51.6%) in all countries.

Conclusion

Some differences were found in breastfeeding beliefs during the COVID-19 pandemic in Asian countries. A positive breastfeeding belief was associated with the practice of breastfeeding at the breast. Women from all countries received postpartum infant feeding support from health professionals and peers / family through personal contacts. Governments need to emphasize and disseminate the importance of breastfeeding safety, especially in Asian countries.

Serial Short-Term Outcomes of Very-Low-Birth-Weight Infants in the Korean Neonatal Network From 2013 to 2020

BACKGROUND

We aimed to determine the current survival rate and short-term outcomes of very-low-birth-weight infants (VLBWIs) in Korea, as well as whether the survival rate and short-term outcomes have improved over time since 2013, which was when the Korean Neonatal Network (KNN) was launched.

METHODS

This study used data from the annual reports of the KNN from 2013 to 2020. A total of 16,351 VLBWIs born at gestational age (GA) ≥ 22 weeks between January 1, 2013, and December 31, 2020, and who were registered in the KNN were enrolled. Serial outcomes were analyzed according to era (2013-14, 2015-16, 2017-18, and 2019-20).

RESULTS

More mothers delivered by cesarean section, had diabetes or hypertension during their pregnancy, and received antenatal steroids when analyzed by era. Fewer infants were intubated at birth and had air leaks when analyzed by era. The overall survival rate of VLBWIs between 2013 and 2020 was 87%. The rate of respiratory distress syndrome was 77% and that of bronchopulmonary dysplasia was 32% between 2013 and 2020. The rates of intraventricular hemorrhage (grade ≥ 3), periventricular leukomalacia, and sepsis decreased over time. The survival rate of infants with a GA of 26 weeks has improved serially according to era.

CONCLUSION

Since the launch of the KNN in 2013, the survival rates of infants with GA 26 weeks and short-term outcomes have improved, which implies a quality improvement in antenatal and delivery room care. Further studies on the long-term neurodevelopmental outcomes of these KNN registrants are warranted.

Intratracheal Transplantation of Mesenchymal Stem Cells Attenuates Hyperoxia-Induced Microbial Dysbiosis in the Lungs, Brain, and Gut in Newborn Rats

We attempted to determine whether intratracheal (IT) transplantation of mesenchymal stem cells (MSCs) could simultaneously attenuate hyperoxia-induced lung injuries and microbial dysbiosis of the lungs, brain, and gut in newborn rats. Newborn rats were exposed to hyperoxia (90% oxygen) for 14 days. Human umbilical cord blood-derived MSCs (5 × 10⁵) were transplanted via the IT route on postnatal day (P) five. At P14, the lungs were harvested for histological, biochemical, and microbiome analyses. Bacterial 16S ribosomal RNA genes from the lungs, brain, and large intestine were amplified, pyrosequenced, and analyzed. IT transplantation of MSCs simultaneously attenuated hyperoxia-induced lung inflammation and the ensuing injuries, as well as the dysbiosis of the lungs, brain, and gut. In correlation analyses, lung interleukin-6 (IL-6) levels were significantly positively correlated with the abundance of Proteobacteria in the lungs, brain, and gut, and it was significantly inversely correlated with the abundance of Firmicutes in the gut and lungs and that of Bacteroidetes in the lungs. In conclusion, microbial dysbiosis in the lungs, brain, and gut does not cause but is caused by hyperoxic lung inflammation and ensuing injuries, and IT transplantation of MSCs attenuates dysbiosis in the lungs, brain, and gut, primarily by their anti-oxidative and anti-inflammatory effects.

Effect of levothyroxine supplementation in extremely low birth weight infants with transient hypothyroxinemia of prematurity

This study aimed to determine the short- and/or long-term outcomes of levothyroxine replacement therapy in extremely low birth weight (ELBW) infants with transient hypothyroxinemia of prematurity (THOP). The medical records of 335 ELBW infants with THOP were reviewed retrospectively to identify whether levothyroxine treatment affects short- and/or long-term outcomes at a corrected age of 2 years. The infants were arbitrarily grouped based on thyroxine (T4) (free T4 [fT4]) levels into group 1 (n = 142), which included infants with T4 (fT4) levels < 2.5 (0.5) ng/dl, and group 2 (n = 193), which included those with T4 (fT4) levels ranging from ≥ 2.5 (0.5) ng/dl to < 4.5 (0.9) ng/dl. Levothyroxine replacement therapy was not associated with beneficial short- or long-term outcomes in ELBW infants with THOP. Short-term outcomes, such as mortality and composite morbidities, and long-term outcomes, such as failure to achieve catch-up height at a corrected age of 2 years, were significantly higher in group 1 than in group 2, regardless of levothyroxine treatment status. Levothyroxine replacement therapy is not associated with short-or long-term advantages in ELBW infants with THOP. This study suggests that the severity of THOP may be the major determinant of adverse outcomes in ELBW infants with THOP, rather than levothyroxine treatment.

Thrombin Preconditioning Improves the Therapeutic Efficacy of Mesenchymal Stem Cells in Severe Intraventricular Hemorrhage Induced Neonatal Rats

Severe intraventricular hemorrhage (IVH) remains a major cause of high mortality and morbidity in extremely preterm infants. Mesenchymal stem cell (MSC) transplantation is a possible therapeutic option, and development of therapeutics with enhanced efficacy is necessary. This study investigated whether thrombin preconditioning improves the therapeutic efficacy of human Wharton’s jelly-derived MSC transplantation for severe neonatal IVH, using a rat model. Severe neonatal IVH was induced by injecting 150 μL blood into each lateral ventricle on postnatal day (P) 4 in Sprague-Dawley rats. After 2 days (P6), naïve MSCs or thrombin-preconditioned MSCs (1 × 10⁵/10 μL) were transplanted intraventricularly. After behavioral tests, brain tissues and cerebrospinal fluid of P35 rats were obtained for histological and biochemical analyses, respectively. Thrombin-preconditioned MSC transplantation significantly reduced IVH-induced ventricular dilatation on in vivo magnetic resonance imaging, which was coincident with attenuations of reactive gliosis, cell death, and the number of activated microglia and levels of inflammatory cytokines after IVH induction, compared to naïve MSC transplantation. In the behavioral tests, the sensorimotor and memory functions significantly improved after transplantation of thrombin-preconditioned MSCs, compared to naïve MSCs. Overall, thrombin preconditioning significantly improves the therapeutic potential and more effectively attenuates brain injury, including progressive ventricular dilatation, gliosis, cell death, inflammation, and neurobehavioral functional impairment, in newborn rats with induced severe IVH than does naïve MSC transplantation.

Development of necrotizing enterocolitis in full-term infants with duct dependent congenital heart disease

Background

Although many studies have described an increased risk of necrotizing enterocolitis in duct dependent congenital heart diseases, very few have investigated its occurrence in full-term infants with duct dependent congenital heart diseases.

Methods

To evaluate the characteristics and risk factors of necrotizing enterocolitis, we performed a retrospective review of 355 full-term infants with duct dependent congenital heart diseases who received prostaglandin E1 therapy from April 2000 to May 2020.

Results

Necrotizing enterocolitis was observed in 10 patients (3.0%). Their average gestational age and birth weight were 38.2 weeks and 2783.5 g, respectively. The median age at diagnosis was 8.0 days (2–70 days). One patient was diagnosed with necrotizing enterocolitis stage IIA, five with stage IIB, two with stage IIIA, and two with stage IIIB; two (20%) received surgical treatment. The duct dependent pulmonary circulation group had higher frequencies of necrotizing enterocolitis (4.4%) than the duct dependent systemic circulation (2.0%) and parallel circulation (1.3%) groups. The necrotizing enterocolitis and the other groups had significantly different birth weight (2783.5 g vs 3170.9 g, respectively) and gestational age (38.2 weeks vs 39.1 weeks, respectively). Gestational age under 38 weeks (OR 8.87, p = 0.002), birth weight of < 2500 g (OR 5.1, p = 0.042), need for mechanical ventilation (OR 4.6, p = 0.021), parenteral nutrition (OR 107.7, p < 0.001), and functional single ventricle (OR 5.8, p = 0.009) were significant risk factors. The case-fatality rate was higher in the necrotizing enterocolitis (40.0%) than in the other group (8.3%, p = 0.009).

Conclusions

Three percent of full-term infants with duct dependent congenital heart diseases developed necrotizing enterocolitis. Neonates with low birth weight, gestational age less than 38 weeks, functional single ventricle, or receiving assisted mechanical ventilation or parenteral nutrition are at increased risk.

Perinatal Outcomes According to Accessibility to Maternal-Fetal and Neonatal Intensive Care Units by Region in Korea

BACKGROUND

Herein, we aimed to evaluate the maternal mortality ratio and perinatal mortality rate for different perinatal medical care service areas (PMCSAs), which were established by considering their geographical accessibility to maternal-fetal intensive care units (MFICUs) and neonatal intensive care units (NICUs), and to compare the PMCSAs according to their accessibility to these perinatal care services.

METHODS

Based on the 70 hospital service areas (HSAs) across the country confirmed through the Dartmouth Atlas methodology analysis and gathering of expert opinions, the PMCSAs were designated by merging HSAs without MFICUs and NICUs to the nearest HSA that contained MFICUs and NICUs, based on which MFICU and NICU could be reached within the shortest amount of time from population-weighted centroids in HSAs. PMCSAs where 30% or more of the population could not access MFICUs and NICUs within 60 minutes were identified using the service module ArcGIS and were defined as having access vulnerability.

RESULTS

Thirty-three of 70 HSAs in the country did not contain MFICUs and NICUs, and 39 PMCSAs were finally derived by merging 70 HSAs. Ten of 39 PMCSAs (25.6%) were classified as having access vulnerability to MFICUs and NICUs. The national maternal mortality ratio was 9.42, with the highest ratio seen in the region of Wonju (25.86) and the lowest in Goyang (2.79). The national perinatal mortality rate was 2.86, with the highest and lowest rates observed in the Gunsan (4.04) and Sejong (1.99) regions, respectively. The perinatal mortality rates for areas vulnerable and invulnerable to maternal and neonatal healthcare accessibility were 2.97 and 2.92, respectively, but there was no statistically significant difference in this rate (P = 0.789). The maternal mortality ratio for areas vulnerable and invulnerable to maternal and neonatal healthcare accessibility were 14.28 and 9.48, respectively; this ratio was significantly higher in areas vulnerable to accessibility (P = 0.022).

CONCLUSION

Of the PMCSAs across the country, 25.6% (10/39) were deemed to be vulnerable to MFICU and NICU accessibility. There was no difference in the perinatal mortality rate between the vulnerable and invulnerable areas, but the maternal mortality ratio in vulnerable areas was significantly higher than that in invulnerable areas.

Increased Risk of Meconium-Related Ileus in Extremely Premature Infants Exposed to Antenatal Magnesium Sulfate

INTRODUCTION

We experienced an increased incidence of meconium-related ileus (MRI) in extremely premature infants (EPIs) while adopting the antenatal magnesium sulfate (MgSO4) protocol for fetal neuroprotection in our neonatal intensive care unit. This study aimed to test whether antenatal MgSO4 use was associated with increased risk of MRI in EPIs.

METHODS

The incidences of complicated MRI requiring aggressive enema or surgical intervention and other intestinal complications were compared among period 1 (January 2012-December 2013, n = 79), before adoption of the antenatal MgSO4 protocol for fetal neuroprotection; period 2 (January 2014-March 2016, n = 72), when the protocol was adopted; and period 3 (April 2016-September 2018, n = 75), when the protocol was temporarily withdrawn due to concern regarding intestinal complications in EPIs.

RESULTS

Despite similar baseline clinical characteristics among infants across the study periods, the MRI and MRI with surgical treatment incidences were higher in period 2 than those in periods 1 and 3 (13% vs. 8% and 6%, p = 0.391, and 11% vs. 0% and 1%, p = 0.001, respectively). In multivariable analysis, exposure to antenatal MgSO4 independently increased the risk of MRI (adjusted odds ratio, 3.8; 95% confidence interval, 1.4, 10.6).

CONCLUSION

Antenatal MgSO4 may increase the risk of MRI, frequently requiring surgical intervention, in EPIs with a gestational age of 25 weeks or less.

Preclinical assessment of thrombin-preconditioned human Wharton's jelly-derived mesenchymal stem cells for neonatal hypoxic-ischaemic brain injury

Hypoxic-ischaemic encephalopathy (HIE) is a type of brain injury affecting approximately 1 million newborn babies per year worldwide, the only treatment for which is therapeutic hypothermia. Thrombin-preconditioned mesenchymal stem cells (MSCs) exert neuroprotective effects by enriching cargo contents and boosting exosome biogenesis, thus showing promise as a new therapeutic strategy for HIE. This study was conducted to evaluate the tissue distribution and potential toxicity of thrombin-preconditioned human Wharton's jelly-derived mesenchymal stem cells (th-hWJMSCs) in animal models before the initiation of clinical trials. We investigated the biodistribution, tumorigenicity and general toxicity of th-hWJMSCs. MSCs were administered the maximum feasible dose (1 × 105 cells/10 µL/head) once, or at lower doses into the cerebral ventricle. To support the clinical use of th-hWJMSCs for treating brain injury, preclinical safety studies were conducted in newborn Sprague-Dawley rats and BALB/c nude mice. In addition, growth parameters were evaluated to assess the impact of th-hWJMSCs on the growth of newborn babies. Our results suggest that th-hWJMSCs are non-toxic and non-tumorigenic in rodent models, survive for up to 7 days in the brain and hold potential for HIE therapy.

BDNF-Overexpressing Engineered Mesenchymal Stem Cells Enhances Their Therapeutic Efficacy against Severe Neonatal Hypoxic Ischemic Brain Injury

We investigated whether irradiated brain-derived neurotropic factor (BDNF)-overexpressing engineered human mesenchymal stem cells (BDNF-eMSCs) improve paracrine efficiency and, thus, the beneficial potency of naïve MSCs against severe hypoxic ischemic (HI) brain injury in newborn rats. Irradiated BDNF-eMSCs hyper-secreted BDNF > 10 fold and were >5 fold more effective than naïve MSCs in attenuating the oxygen-glucose deprivation-induced increase in cytotoxicity, oxidative stress, and cell death in vitro. Only the irradiated BDNF-eMSCs, but not naïve MSCs, showed significant attenuating effects on severe neonatal HI-induced short-term brain injury scores, long-term progress of brain infarct, increased apoptotic cell death, astrogliosis and inflammatory responses, and impaired negative geotaxis and rotarod tests in vivo. Our data, showing better paracrine potency and the resultant better therapeutic efficacy of the irradiated BDNF-eMSCs, compared to naïve MSCs, suggest that MSCs transfected with the BDNF gene might represent a better, new therapeutic strategy against severe neonatal HI brain injury.

Stem cell restores thalamocortical plasticity to rescue cognitive deficit in neonatal intraventricular hemorrhage

Severe neonatal intraventricular hemorrhage (IVH) patients incur long-term neurologic deficits such as cognitive disabilities. Recently, the intraventricular transplantation of allogeneic human umbilical cord blood-derived mesenchymal stem cells (MSCs) has drawn attention as a therapeutic potential to treat severe IVH. However, its pathological synaptic mechanism is still elusive. We here demonstrated that the integration of the somatosensory input was significantly distorted by suppressing feed-forward inhibition (FFI) at the thalamocortical (TC) inputs in the barrel cortices of neonatal rats with IVH by using BOLD-fMRI signal and brain slice patch-clamp technique. This is induced by the suppression of Hebbian plasticity via an increase in tumor necrosis factor-α expression during the critical period, which can be effectively reversed by the transplantation of MSCs. Furthermore, we showed that MSC transplantation successfully rescued IVH-induced learning deficits in the sensory-guided decision-making in correlation with TC FFI in the layer 4 barrel cortex.

Stem cells for bronchopulmonary dysplasia in preterm infants: A randomized controlled phase II trial

We previously demonstrated the safety and feasibility of mesenchymal stem cell (MSC) transplantation for bronchopulmonary dysplasia (BPD) in preterm infants in a phase I clinical trial. We thus investigated the therapeutic efficacy of MSCs for BPD in premature infants. A phase II double-blind, randomized, placebo-controlled clinical trial was conducted on preterm infants at 23 to 28 gestational weeks (GW) receiving mechanical ventilator support with respiratory deterioration between postnatal days 5 and 14. Infants were stratified by 23 to 24 GW and 25 to 28 GW and randomly allocated (1:1) to receive stem cells (1 × 10⁷ cells/kg, n = 33) or placebo (n = 33). Although the inflammatory cytokines in the tracheal aspirate fluid were significantly reduced with MSCs, the primary outcome of death or severe/moderate BPD in the control group (18/33, 55%) was not significantly improved with MSC transplantation (17/33, 52%). In the subgroup analysis, the secondary outcome of severe BPD was significantly improved from 53% (8/15) to 19% (3/16) with MSC transplantation in the 23 to 24 GW group but not in the 25 to 28 GW subgroup. In summary, although MSC transplantation might be safe and feasible, this small study was underpowered to detect its therapeutic efficacy in preterm infants at 23 to 28 GW. Accordingly, we are now conducting an additional larger and controlled phase II clinical trial focusing on infants at 23 to 24 GW (NCT03392467). ClinicalTrials.gov identifier: NCT01828957.

Neonatal Outcomes according to the Latent Period from Membrane Rupture to Delivery among Extremely Preterm Infants Exposed to Preterm Premature Rupture of Membrane: a Nationwide Cohort Study

BACKGROUND

In accordance with the guidelines for the expectant management of women exposed to previable preterm premature rupture of membrane, we compared neonatal outcomes according to the latent period from membrane rupture to delivery among extremely preterm infants exposed to maternal preterm premature rupture of membrane using the Korean Neonatal Network database.

METHODS

Of the 3,305 extremely preterm infants born at 23-27 weeks' gestation between 2014 and 2017 who were registered in the Korean Neonatal Network, 1,464 infants were born to pregnant women who were exposed to preterm premature rupture of membrane. The short latency group was defined as infants born with a latent period between membrane rupture and delivery < 7 days (n = 450), whereas the prolonged latency group was defined as infants born with a latent period of ≥ 7 days (n = 434). Using well-established risk factors for adverse short-term outcomes, multivariate logistic regression analysis was performed to assess a prolonged latent period in preterm premature rupture of membrane as an independent risk factor for neonatal outcomes in extremely preterm infants exposed to preterm premature rupture of membrane.

RESULTS

The mean gestational age at membrane rupture in the prolonged latency group was significantly lower than that in the short latency group (22.7 ± 2.5 vs. 25.4 ± 1.3 weeks, P < 0.001). Nevertheless, the mean gestational age at delivery and birth weight were not significantly different between the two groups. The incidence of oligohydramnios and histologic chorioamnionitis in the prolonged latency group was significantly higher than that in the short latency group (38.7 [155/401] vs. 26.1 [105/403], 69.8 [270/384] vs. 61.0 [242/397], respectively, P < 0.05). The survival rate in the prolonged latency group did not differ from that in the short latency group (71.2 [309/434] vs. 73.3 [330/450], P = 0.478). Although the prolonged latency group was not associated with mortality during hospitalization in the multivariate logistic regression analysis, the prolonged latency group's early pulmonary hypertension and bronchopulmonary dysplasia rates were increased by 1.8 and 1.5 times, respectively.

CONCLUSION

A prolonged latent period of 7 days or more does not affect the survival rate but increases the risk of bronchopulmonary dysplasia occurrence among extremely preterm infants who are exposed to maternal preterm premature rupture of membrane.

Mortality and Morbidities according to Time of Birth in Extremely Low Birth Weight Infants

BACKGROUND

Although the overall quality of high-risk neonatal care has improved recently, there is still concern about a difference in the quality of care when comparing off-hour births and regular-hour births. Moreover, there are no data in Korea regarding the impact of time of birth on mortality and morbidities in preterm infants.

METHODS

A total of 3,220 infants weighing < 1,000 g and born at 23-34 weeks in 2013-2017 were analyzed based on the Korean Neonatal Network data. Mortality and major morbidities were analyzed using logistic regression according to time of birth during off-hours (nighttime, weekend, and holiday) and regular hours. The institutes were sub-grouped into hospital group I and hospital group II based on the neonatal intensive care unit (NICU) care level defined by the mortality rates of < 50% and ≥ 50%, respectively, in infants born at 23-24 weeks' gestation.

RESULTS

The number of births during regular hours and off-hours was similar. In the total population and hospital group I, off-hour births were not associated with increased neonatal mortality and morbidities. However, in hospital group II, increased early mortality was found in the off-hour births when compared to regular-hour births.

CONCLUSION

Efforts to improve the overall quality of NICU are required to lower the early mortality rate in off-hour births. Also, other sensitive indexes for the evaluation of quality of NICU care should be further studied.

Mesenchymal stem cell therapy for intractable neonatal disorders

Mesenchymal stem cell (MSC) transplantation has emerged as a new promising therapeutic strategy for the treatment of intractable and devastating neonatal disorders with complex multifactorial etiologies, including bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), and hypoxic-ischemic encephalopathy (HIE). In response to inflammatory and noxious environments, MSCs secrete various paracrine factors that perform several reparative functions, including exerting anti-inflammatory, anti-oxidative, anti-apoptotic, and anti-fibrotic effects, to enhance the regeneration of damaged cells and tissues. In this review, we summarize recent advances in stem cell research focusing on the use of MSCs in the prevention and treatment of newborn BPD, IVH and HIE, with particular emphasis on preclinical and clinical data.

Brain-derived neurotropic factor mediates neuroprotection of mesenchymal stem cell-derived extracellular vesicles against severe intraventricular hemorrhage in newborn rats

Brain-derived neurotropic factor (BDNF), which is secreted by mesenchymal stem cells (MSCs), protects against severe intraventricular hemorrhage (IVH)-induced brain injuries. Although the paracrine protective effects of MSCs are mediated primarily by extracellular vesicles (EVs), the therapeutic efficacy of MSC-derived EVs and the role of the BDNF in the EVs have not been studied. This study aimed to determine whether MSC-derived EVs attenuate severe IVH-induced brain injuries, and if so, whether this protection is mediated by BDNF transfer. We compared the therapeutic efficacy of MSCs, MSC-derived EVs with or without BDNF knockdown, and fibroblast-derived EVs in vitro in rat cortical neuronal cells challenged with thrombin and in vivo in newborn rats by injecting 200 μL of blood at postnatal day (P) 4 and transplanting 1 × 10⁵ MSCs or 20 μg of EVs at P6. The MSCs and MSC-derived EVs, but not the EVs derived from BDNF-knockdown MSCs or fibroblasts, significantly attenuated in vitro thrombin-induced neuronal cell death and in vivo severe IVH-induced brain injuries such as increased neuronal cell death, astrogliosis, and inflammatory responses; reduced myelin basic protein and neurogenesis; led to progression of posthemorrhagic hydrocephalus; and impaired behavioral test performance. Our data indicate that MSC-derived EVs are as effective as parental MSCs in attenuating severe IVH-induced brain injuries, and this neuroprotection is primarily mediated by BDNF transfer via EVs.

Survival rate dependent variations in retinopathy of prematurity treatment rates in very low birth weight infants

As increased oxidative stress causes increased mortality and morbidities like bronchopulmonary dysplasia (BPD) and retinopathy of prematurity (ROP) in very low birth weight infants (VLBWIs), the conundrum of improved survival but increased ROP observed with the high oxygen saturation target range of 91–95% is difficult to explain. To determine the survival rate-dependent variation in ROP treatment rate, 6292 surviving eligible VLBWIs registered in the Korean Neonatal Network were arbitrarily grouped according to the survival rate of infants at 23–24 weeks’ gestation as group I (> 70%, n = 1626), group II (40–70%, n = 2984) and group III (< 40%, n = 1682). Despite significantly higher survival and lower BPD rates in group I than in groups II and III, the ROP treatment rate was higher in group I than in groups II and III. However, the adjusted odds ratios for ROP treatment were not significantly different between the study groups, and the ROP treatment rate in the infants at 23–24 weeks’ gestation was 21-fold higher than the infants at ≥ 27 weeks’ gestation. The controversial association between improved survival and reduced BPD reflecting quality improvement of neonatal intensive care but increased ROP treatment rate might be primarily attributed to the improved survival of the most immature infants.

Fish Oil Monotherapy for Intestinal Failure-Associated Liver Disease on SMOFlipid in the Neonatal Intensive Care Unit

Intestinal failure-associated liver disease (IFALD) is a life-threatening complication of parenteral nutrition (PN) and is most prevalent in the preterm neonatal population receiving long-term PN. In this study, we report the outcome of our experience with fish oil monotherapy for IFALD in a fish oil-based combination lipid emulsion administered to preterm low birth weight infants. Fasting neonates were administered as PN according to our center's nutrition protocol. A diagnosis of IFALD was made when the serum direct bilirubin levels were >2.0 mg/dL in two consecutive measurements that were more than one week apart, without evidence of intrinsic causes of liver dysfunction. The management of IFALD was conducted by switching the lipid emulsion from combination lipid emulsion to fish oil monotherapy at 1.0 g/kg/day, infused over 24 h. Fifteen infants met the criteria for IFALD and received fish oil monotherapy. The median gestational age was 27.5 weeks and the median birth weight was 862.5 g. IFALD was successfully reversed in 11 infants (11/15, 73.3%). The median duration of fish oil monotherapy was 39 days. Direct bilirubin values were initially elevated and then steadily declined from the third week of treatment onward. The enteral tolerance increased in varying degrees during the treatment period. The mean weight gain was 26.0 g/day during fish oil monotherapy. Omegaven^® (Fresenius Kabi Austria Gmbh, Graz, Austria) at a dose of 1.0 g/kg/day was well tolerated, and no adverse events related to Omegaven use were seen. The reversal of IFALD in preterm infants on combination lipid emulsion containing fish oil was achieved by switching to fish oil monotherapy.

Mortality rate-dependent variations in antenatal corticosteroid-associated outcomes in very low birth weight infants with 23-34 weeks of gestation: A nationwide cohort study

Antenatal corticosteroid (ACS) administration has been known as one of the most effective treatment in perinatal medicine, but the beneficial effects of ACS may vary not only gestational age, but also the quality of perinatal and neonatal care of the institution. This nationwide cohort study of the Korean Neonatal Network (KNN) data was consisted of <1,500g infants born at 23–34 weeks at 67 KNN hospitals between 2013 and 2017. The 9,142 eligible infants were assigned into two groups–group 1 and 2 <50% and ≥50% mortality rate, respectively, for 23–24 weeks’ gestation–reflecting the quality of perinatal and neonatal care. Each group of infants were further stratified into 23–24, 25–26, 27–28, and 29–34 weeks of gestation age. Despite comparable ACS usage between group 1 (82%) and group 2 (81%), the benefits of ACS were only observed in group 1. In the multivariable analyses, infants of group 1 showed significant decrease in mortality and IVH at gestational age 23–24 weeks with ACS use, and the decrease was also seen in early-onset sepsis and respiratory distress syndrome at gestational age of 29–34 weeks while there were no significant decrease in group 2. In this study the overall data was congruent with the previous findings stating that ACS use decreases mortality and morbidity. These results indicate that the improved mortality of infants at 23–24 weeks’ gestation reflects the quality improvement of perinatal and neonatal intensive care, which is a prerequisite to the benefits of ACS.