[Treatment of patent ductus arteriosus in very preterm infants in China]

Objective: To describe the current status and trends in the treatment of patent ductus arteriosus (PDA) among very preterm infants (VPI) admitted to the neonatal intensive care units (NICU) of the Chinese Neonatal Network (CHNN) from 2019 to 2021, and to compare the differences in PDA treatment among these units. Methods: This was a cross-sectional study based on the CHNN VPI cohort, all of 22 525 VPI (gestational age<32 weeks) admitted to 79 tertiary NICU within 3 days of age from 2019 to 2021 were included. The overall PDA treatment rates were calculated, as well as the rates of infants with different gestational ages (≤26, 27-28, 29-31 weeks), and pharmacological and surgical treatments were described. PDA was defined as those diagnosed by echocardiography during hospitalization. The PDA treatment rate was defined as the number of VPI who had received medication treatment and (or) surgical ligation of PDA divided by the number of all VPI. Logistic regression was used to investigate the changes in PDA treatment rates over the 3 years and the differences between gestational age groups. A multivariate Logistic regression model was constructed to compute the standardized ratio (SR) of PDA treatment across different units, to compare the rates after adjusting for population characteristics. Results: A total of 22 525 VPI were included in the study, with a gestational age of 30.0 (28.6, 31.0) weeks and birth weight of 1 310 (1 100, 1 540) g; 56.0% (12 615) of them were male. PDA was diagnosed by echocardiography in 49.7% (11 186/22 525) of all VPI, and the overall PDA treatment rate was 16.8% (3 795/22 525). Of 3 762 VPI who received medication treatment, the main first-line medication used was ibuprofen (93.4% (3 515/3 762)) and the postnatal day of first medication treatment was 6 (4, 10) days of age; 59.3% (2 231/3 762) of the VPI had been weaned from invasive respiratory support during the first medication treatment, and 82.2% (3 092/3 762) of the infants received only one course of medication treatment. A total of 143 VPI underwent surgery, which was conducted on 32 (22, 46) days of age. Over the 3 years from 2019 to 2021, there was no significant change in the PDA treatment rate in these VPI (P=0.650). The PDA treatment rate decreased with increasing gestational age (P<0.001). The PDA treatment rates for VPI with gestational age ≤26, 27-28, and 29-31 weeks were 39.6% (688/1 737), 25.9% (1 319/5 098), and 11.4% (1 788/15 690), respectively. There were 61 units having a total number of VPI≥100 cases, and their rates of PDA treatment were 0 (0/116)-47.4% (376/793). After adjusting for population characteristics, the range of standardized ratios for PDA treatment in the 61 units was 0 (95%CI 0-0.3) to 3.4 (95%CI 3.1-3.8). Conclusions: From 2019 to 2021, compared to the peers in developed countries, VPI in CHNN NICU had a different PDA treatment rate; specifically, the VPI with small birth gestational age had a lower treatment rate, while the VPI with large birth gestational age had a higher rate. There are significant differences in PDA treatment rates among different units.

Impaired function of skeletal stem cells derived from growth plates in ovariectomized mice

INTRODUCTION

Mouse skeletal stem cells (mSSCs, CD45^-Ter119^-Tie2^-CD51⁺Thy^-6C3^-CD105^-CD200⁺population) are identified in growth plates (GP) and play important roles in bone regeneration. However, the role of mSSCs in osteoporosis remains unclear.

MATERIALS AND METHODS

The GP were stained by HE staining, and the mSSC lineage was analyzed by flow cytometry at postnatal of 14 days and 30 days in wild-type mice. The mice (8 weeks) were either sham operated or ovariectomy (OVX) and then sacrificed at 2, 4 and 8 w. The GP were stained by Movat staining, and mSSC lineage was analyzed. Then, mSSCs were sorted by fluorescence-activated cell sorting (FACS); the clonal ability, chondrogenic differentiation and osteogenic differentiation were evaluated, and the changed genes were analyzed by RNA-seq.

RESULTS

The percentage of mSSCs were decreased with the narrow GP. Heights of GP were decreased significantly in 8w-ovx mice compared with 8w-sham mice. We found the percentage of mSSCs were decreased in mice at 2w after ovx, but the cell numbers were not changed. Further, the percentage and cell numbers of mSSCs were not changed at 4w and 8w after ovx. Importantly, the clonal ability, chondrogenic differentiation and osteogenic differentiation of mSSCs were impaired at 8w after ovx. We found 114 genes were down-regulated in mSSCs, including skeletal developmental genes such as Col10a1, Col2a1, Mef2c, Sparc, Matn1, Scube2 and Dlx5. On the contrary, 526 genes were up-regulated, including pro-inflammatory genes such as Csf1, Nfkbla, Nfatc2, Nfkb1 and Nfkb2.

CONCLUSION

Function of mSSCs was impaired by up-regulating pro-inflammatory genes in ovx-induced osteoporosis.

[A comparison of the clinical diagnosis and outcome in preterm infants with bronchopulmonary dysplasia under two different diagnostic criteria]

Objective: To compare the clinical diagnosis and outcomes of preterm infants with bronchopulmonary dysplasia (BPD) under two different diagnostic criteria. Methods: A retrospective study was performed in 157 preterm infants who were admitted to Neonatal Intensive Care Unit of the Children's Hospital, Zhejiang University School of Medicine from January 2015 to December 2018. Enrolled infants, with gestational age <32 weeks and survived >14 days, met the 2001 National Institute of Child Health and Human Development(NICHD) definition of moderate and severe BPD or died between 14 days of postnatal age and 36 weeks owing to persistent parenchymal lung disease and respiratory failure. The severities of BPD were revaluated according to the 2018 revised definition of BPD proposed by NICHD. Characteristics and outcomes of these infants were compared with the two different diagnostic criteria with t-test, nonparametric test or Chi-square test. Results: In the 157 enrolled infants (100 males), severities of BPD were classified as moderate in 62, severe in 84 and unclassifiable in 11 according to the 2001 NICHD criteria, while grade Ⅰ in 51, Ⅱ in 29, Ⅲ in 66 and ⅢA in 11 infants respectively according to the 2018 NICHD criteria. Duration of oxygen therapy, positive pressure ventilation and endotracheal intubation in grade Ⅱinfants of 2018 criteria were much longer than that in moderate infants of 2001 criteria (80 (65, 95) vs. 65 (59, 77) d, 52 (38, 58) vs.30 (19, 48) d, 10 (2, 17) vs.4 (0, 12) d, Z=-2.995, -3.750, -2.073, all P<0.05). Mortality of moderate and severe infants in 2001 criteria was 10.3% (15/146), while mortality of BPD in 2018 criteria was 16.6% (26/157). Mortality of grade Ⅲ and ⅢA BPD in 2018 criteria was much higher than mortality of severe BPD in 2001 criteria (33.8% (26/77) vs. 17.9%(15/84), χ(2)=5.357, P<0.05). Conclusion: Definition and classification of BPD based on 2001 NICHD criteria may cause missed or unclassified cases, resulting in the underestimation of the morbidity and mortality of infants with severe BPD.

Arginine bioavailability and endothelin-1 system in the regulation of vascular function of umbilical vein endothelial cells from intrauterine growth restricted newborns

BACKGROUND AND AIMS

Intrauterine growth restriction (IUGR) is a major risk factor for perinatal morbidity and mortality, leading to long-term adverse cardiovascular outcomes. The present study aimed to investigate the potential mechanisms in IUGR-associated vascular endothelial dysfunction.

METHODS AND RESULTS

Human umbilical vein endothelial cells (HUVECs) were derived from IUGR or normal newborns. We found that the proliferation of IUGR-derived HUVECs was accelerated compared to those from normal subjects. Gene profiles related to vascular function including vasomotion, oxidative stress, and angiogenesis were dysregulated in IUGR-HUVECs. Compared with HUVECs from normal newborns, nitric oxide (NO) production was reduced, with imbalance between endothelial nitric oxide synthase (eNOS) and arginase-2 (Arg-2) in IUGR. Meanwhile, intracellular asymmetric dimethylarginine (ADMA) level was elevated with diminished dimethylarginine dimethylaminohydrolase 1 (DDAH1) expression in IUGR-HUVECs. Furthermore, endothelin-1 (ET-1) and hypoxia-inducible factor 1α (HIF-1α) expression were increased, and endothelin receptor type-B (ET_BR) was reduced in the IUGR group. IUGR-HUVECs exposed to hypoxia increased the ratio of ADMA to l-arginine, HIF-1α and protein arginine methyltransferase 1 (PRMT1) expression compared to controls.

CONCLUSIONS

The present study demonstrated that the reduction of NO bioavailability and release results from elevated Arg-2, accumulation of intracellular ADMA, and imbalance of ET-1 and ET_BR, further leading to IUGR-associated vascular endothelial dysfunction. Our study provides novel evidence on the mechanism underlying fetal programming associated with IUGR, which will serve as potential therapeutic targets in the prevention of adverse cardiovascular consequences in adulthood.

Tyrosine phosphorylation of Kv1.5 is upregulated in intrauterine growth retardation rats with exaggerated pulmonary hypertension

Intrauterine growth retardation (IUGR) is associated with the development of adult-onset diseases, including pulmonary hypertension. However, the underlying mechanism of the early nutritional insult that results in pulmonary vascular dysfunction later in life is not fully understood. Here, we investigated the role of tyrosine phosphorylation of voltage-gated potassium channel 1.5 (Kv1.5) in this prenatal event that results in exaggerated adult vascular dysfunction. A rat model of chronic hypoxia (2 weeks of hypoxia at 12 weeks old) following IUGR was used to investigate the physiological and structural effect of intrauterine malnutrition on the pulmonary artery by evaluating pulmonary artery systolic pressure and vascular diameter in male rats. Kv1.5 expression and tyrosine phosphorylation in pulmonary artery smooth muscle cells (PASMCs) were determined. We found that IUGR increased mean pulmonary artery pressure and resulted in thicker pulmonary artery smooth muscle layer in 14-week-old rats after 2 weeks of hypoxia, while no difference was observed in normoxia groups. In the PASMCs of IUGR-hypoxia rats, Kv1.5 mRNA and protein expression decreased while that of tyrosine-phosphorylated Kv1.5 significantly increased. These results demonstrate that IUGR leads to exaggerated chronic hypoxia pulmonary arterial hypertension (CH-PAH) in association with decreased Kv1.5 expression in PASMCs. This phenomenon may be mediated by increased tyrosine phosphorylation of Kv1.5 in PASMCs and it provides new insight into the prevention and treatment of IUGR-related CH-PAH.

[Use of noninvasive high-frequency oscillatory ventilation in very low birth weight infants]

Objective: To evaluate the effectiveness and safety of the use of noninvasive high-frequency oscillation ventilation (nHFOV) in very low birth weight infants. Method: A total of 36 cases received nHFOV between January 2016 and October 2016 in Children's Hospital, Zhejiang University School of Medicine, including 24 males and 12 females, with the gestational age of (27.5±2.5) weeks and birth weight of(980±318)g. The data of the ventilator settings, side effects, and changes of the respiratory function before and after nHFOV were collected and analyzed retrospectively. Nonparametric tests or t tests or χ(2) tests were used. Result: Thirty-two (89%) out of the 36 cases successfully avoided intubation or re-intubation after using of nHFOV. nHFOV was used as the rescue treatment after failure of other noninvasive ventilation in 17 cases, and as the prophylactical treatment preventing re-intubation after extubation in the remaining 19 cases. There were significant decreases in the incidences of apnea and desaturation(SpO(2)<0.85), the level of PaCO(2, )and the FiO(2) 24 h after the initiation of the nHFOV as the rescue therapy((1.2±1.1)vs.(6.3±2.1)episodes , (1.1±1.2) vs.(4.3±1.5) episodes, (43±8) vs.(56±10) mmHg, 0.30±0.07 vs. 0.39±0.11, respectively; 1 mmHg=0.133 kPa, t=7.562, 8.913, 4.179, 3.437 respectively, all P<0.01). No significant changes were found in FiO(2) and PaCO(2) levels 24 h after initiation of nHFOV as the prophylactical therapy after extubation (0.42±0.12 vs.0.40±0.10, (49±8)vs.(48±7)mmHg, t=0.872 and 0.501 respectively, both P>0.05), except for the significant decreases in the mean airway pressure ((7.9±2.6)vs.(9.6±1.6)cmH(2)O, 1 cmH(2)0=0.098 kPa, t=2.198, P=0.041). There were 4 cases suffered from nasal septum injury, while no other nHFOV related complications were noted. Conclusion: nHFOV can be applied in preterm infants as a rescue treatment after the failure of other noninvasive ventilation, or prophylactically used in patients who have high risk of re-intubation.

[An analysis of 181 cases with blood stream infection caused by Streptococcus agalactiae in children from 2011 to 2015: a multi-center retrospective study]

OBJECTIVE

To analyze the clinical characteristics of blood stream infection caused by Streptococcus agalactiae in children and the drug-resistance of the isolates.

METHOD

All cases with Streptococcus agalactiae growth in blood or cerebrospinal fluid cultures from January 1, 2011 to December 31, 2015 were enrolled by checking the laboratory information system (LIS) from 7 Class 3 Grade A hospitals (4 in Zhejiang, 2 in Shanghai and 1 in Chongqing). Clinical data were collected for analysis. χ(2) test, t test and non parametric test were used in the study.

RESULT

One hundred and eighty-one pediatric cases of blood stream infection caused by Streptococcus agalactiae were included in current study. Eighty-six cases (47.5%) were male, and with age range from one day to 9 years (media 13 days). Thirty cases (16.6%) were premature infants and 127 cases (70.2%) were born via vaginal delivery. Seventy-one cases (39.2%) had early onset (<7 d) infections, and 106 cases (58.6%) had late onset (7-89 d) infections. Seventy-eight cases (43.1%) were complicated with purulent meningitis. Incidences of vaginal delivery(81.7%(58/71) vs. 62.3%(66/106)), shortness of breath moaning (43.7%(31/71) vs. 15.1%(16/106)) and preterm premature rupture of membranes (25.4%(18/71) vs. 3.8%(4/106)) were higher in the early onset infection group compared with the late onset group(P all<0.05). However, the number of cases who had fever(25.4%(18/71)vs.85.8%(91/106)) and complicated with purulent meningitis (29.6%(21/71) vs. 53.8%(57/106)) in early onset infections group was less than that in the late onset group(P both<0.05). The blood cultures of most patients (87.8%) were performed before the use of antibiotics. Drug-resistant tests showed that the sensitive rates to penicillin G, ceftriaxone and cefotaxime were 98.9%, 99.0% and 99.0% respectively. All strains were sensitive to vancomucine. The rates of resistance to clindamycin and erythromycin were 68.0% and 34.0%, respectively. Only 39 cases (22.0%) were treated with single antibiotics of either penicillins or cephalosporins, 80 cases (45.2%) were treated with antibiotics containing β lactamase inhibitor, 61 cases (34.5%) were treated with either meropenem or cefoperazone-sulbactam. One hundred and fifty-four cases were cured, while 19 died (including 13 complicated with purulent meningitis) and 8 lost to follow up after giving up of treatment.

CONCLUSION

The incidence and mortality of blood stream infection caused by Streptococcus agalactiae complicated with purulent meningitis are high in children. Penicillin is the first choice in treatment. Antibiotics should be selected accorrding to the drug-resistance test.

[Extracorporeal membrane oxygenation for rescuing 12 children with acute fulminant myocarditis]

Objective: To summarize clinical experience of using extracorporeal membrane oxygenation (ECMO) in rescuing children with acute fulminant myocarditis (AFM). Method: Data of 12 children with acute fulminate myocarditis (6 boys and 6 girls, median age 8.3 (0.6, 13.0) years, median weight 33.1 (6, 61) kg) who were rescued with ECMO in Children's Hospital, Zhejiang University from September 2009 to August 2015 were analyzed retrospectively. The analysis focused on the intervene timing of ECMO for the cardiogenic shock and hypoperfusion caused by heart failure and(or) lethal arrhythmia and the essentials of ECMO cardiopulmonary resuscitation(ECPR) for cardiac arrest in pediatric AFM were summarized. Result: The median ECMO duration was 110(22, 240) h. Ten cases survived and 2 were dead of the total of 12 patients. Six ECPR patients survived and 2 were dead in the total of 8 ECPR patients. The complication of 10 survivors were cannula site bleeding (3 cases), hypernatremia and intracranial hemorrhage (1 case), limping (1 case), hoarse voice (1 case), and cerebral injury (1 case). Conclusion: The key points of improving ECMO rescuing outcome for the AFM children are grasping the ECMO intervene timing and training skilled ECMO team. For ECPR patients, keeping effective chest compressions resuscitation is the key to achieve survival and improve the quality of life.

Association of cytokine responses with disease severity in infants with respiratory syncytial virus infection

AIM

To explore the relationship between cytokine responses and severity of respiratory syncytial virus (RSV) infection in infants.

METHODS

Intracellular interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) expression in peripheral blood CD3+ and CD8+ lymphocytes was measured by four-colour flow cytometry. Serum IL-12, IL-4 and IFN-gamma levels were also determined by enzyme-linked immunosorbent assay.

RESULTS

The frequency of IL-4 and IFN-gamma expression in CD3+CD8- cells was the same in RSV-infected, non-RSV-infected and control infants and in those with RSV bronchiolitis or RSV pneumonia, indicating that no Th2 predominance exists in the acute phase of RSV infection and RSV bronchiolitis. Furthermore, RSV-infected infants had a more frequent IFN-gamma expression in CD3+CD8+ cells than controls, and they also showed a much lower serum IL-4/ IFN-gamma ratio because of decreased IL-4 and elevated IFN-gamma, the latter being most prominent in RSV bronchiolitis. The serum IL-12 level in RSV-infected infants was the same as in control infants, while those with non-RSV infections had a much higher level. Serum IL-12, IFN-gamma and frequency of IFN-gamma expression in CD3+CD8+ cells in mild RSV infection were much higher than in controls, while no difference existed between severe cases and controls.

CONCLUSION

Type 2 cytokine predominance was not found in the acute phase of RSV infection and RSV bronchiolitis, but both were accompanied by enhanced production of IFN-gamma and a much higher serum IFN-gamma level than in healthy controls, especially in those with RSV bronchiolitis, suggesting a role in causing airway obstruction. IFN-gamma and IL-12 may also play a protective role in RSV infections by diminishing viral replication, and high levels of IL-12 and IFN-gamma may be associated with lessening of the severity of infection.