Treatment of neonates with respiratory distress syndrome by proportional assist ventilation plus synchronized intermittent mandatory ventilation: a comparison study.

BACKGROUND: The proportion assisted ventilation (PAV) can improve patient-ventilator interaction, reducing the incidence of end-expiratory asynchrony and increasing the time of synchrony. PAV could compensate for the leaks by elastic and resistive unloading and thus is ideal for neonates with uncuffed airways. The aim of this study was to compare the relevant clinical parameters of neonates with respiratory distress syndrome (RDS) who are supported by PAV plus synchronized intermittent mandatory ventilation (SIMV) and SIMV. METHODS: Forty-six neonates diagnosed as RDS who required mechanical ventilation were randomly divided into observer group (support by PAV+SIMV mode, N.=23) and control group (support by SIMV mode, N.=23). The X-ray grading situation, the number of asynchrony-delayed trigger, mean arterial blood pressure (MABP), spontaneous respiratory rate (RR), heart rate (HR), blood gas analysis values and circulation and respiratory parameters at each timepoint after 30 minutes, 12, 24, 48 and 72 hours of mechanical ventilation were observed. RESULTS: The forty-four neonates in two groups have been cured, the other 2 neonates (one in each group) gave up treatment and automatically discharged. There were no statistically significant differences in male, gestational age, body weight, duration of mechanical ventilation, oxygen dependence and hospital stay between the two groups (all P>0.05). There were no statistically significant differences in MABP, HR and ratio of arterial-to-alveolar partial pressure of oxygen (a/APO2) at each time point after mechanical ventilation between the two groups(all P>0.05). The number of asynchrony-delayed trigger in observer group was lower than that in control group, the difference was statistically significant (P<0.05). The number of spontaneous RR in observer group was higher than that in control group. The difference was statistically significant (P<0.05). CONCLUSIONS: The PAV plus SIMV shows a good clinical effect in treatment of neonates with RDS. It could be better to use neonatal spontaneous breathing and might cause less damage to the lung than SIMV mode.

Role of the LRP1-pPyk2-MMP9 pathway in hyperoxia-induced lung injury in neonatal rats. / LRP1-pPyk2-MMP9é€šè·¯åœ¨é«˜æ°§è¯±å¯¼æ–°ç”Ÿå¤§é¼ è‚ºæŸä¼¤ä¸­çš„ä½œç”¨.

OBJECTIVES: To study the role of the low-density lipoprotein receptor-related protein 1 (LRP1)-proline-rich tyrosine kinase 2 phosphorylation (pPyk2)-matrix metalloproteinases 9 (MMP9) pathway in hyperoxia-induced lung injury in neonatal rats. METHODS: A total of 16 neonatal rats were randomly placed in chambers containing room air (air group) or 95% medical oxygen (hyperoxia group) immediately after birth, with 8 rats in each group. All of the rats were sacrificed on day 8 of life. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissue. ELISA was used to measure the levels of soluble LRP1 (sLRP1) and MMP9 in serum and bronchoalveolar lavage fluid (BALF). Western blot was used to measure the protein expression levels of LRP1, MMP9, Pyk2, and pPyk2 in lung tissue. RT-PCR was used to measure the mRNA expression levels of LRP1 and MMP9 in lung tissue. RESULTS: The hyperoxia group had significantly higher levels of sLRP1 and MMP9 in serum and BALF than the air group (P<0.05). Compared with the air group, the hyperoxia group had significant increases in the protein expression levels of LRP1, MMP9, and pPyk2 in lung tissue (P<0.05). The hyperoxia group had significantly higher relative mRNA expression levels of LRP1 and MMP9 in lung tissue than the air group (P<0.05). CONCLUSIONS: The activation of the LRP1-pPyk2-MMP9 pathway is enhanced in hyperoxia-induced lung injury in neonatal rats, which may be involved in the pathogenesis of bronchopulmonary dysplasia.

[Clinical features of preterm infants with a birth weight less than 1 500 g undergoing different intensities of resuscitation: a multicenter retrospective analysis].

OBJECTIVE: To evaluate the clinical features of preterm infants with a birth weight less than 1 500 g undergoing different intensities of resuscitation. METHODS: A retrospective analysis was performed for the preterm infants with a birth weight less than 1 500 g and a gestational age less than 32 weeks who were treated in the neonatal intensive care unit of 20 hospitals in Jiangsu, China from January 2018 to December 2019. According to the intensity of resuscitation in the delivery room, the infants were divided into three groups:non-tracheal intubation (n=1 184), tracheal intubation (n=166), and extensive cardiopulmonary resuscitation (ECPR; n=116). The three groups were compared in terms of general information and clinical outcomes. RESULTS: Compared with the non-tracheal intubation group, the tracheal intubation and ECPR groups had significantly lower rates of cesarean section and use of antenatal corticosteroid (P < 0.05). As the intensity of resuscitation increased, the Apgar scores at 1 minute and 5 minutes gradually decreased (P < 0.05), and the proportion of infants with Apgar scores of 0 to 3 at 1 minute and 5 minutes gradually increased (P < 0.05). Compared with the non-tracheal intubation group, the tracheal intubation and ECPR groups had significantly higher mortality rate and incidence rates of moderate-severe bronchopulmonary dysplasia and serious complications (P < 0.05). The incidence rates of grade Ⅲ-Ⅳ intracranial hemorrhage and retinopathy of prematurity (stage Ⅲ or above) in the tracheal intubation group were significantly higher than those in the non-tracheal intubation group (P < 0.05). CONCLUSIONS: For preterm infants with a birth weight less than 1 500 g, the higher intensity of resuscitation in the delivery room is related to lower rate of antenatal corticosteroid therapy, lower gestational age, and lower birth weight. The infants undergoing tracheal intubation or ECRP in the delivery room have an increased incidence rate of adverse clinical outcomes. This suggests that it is important to improve the quality of perinatal management and delivery room resuscitation to improve the prognosis of the infants.

Nitrogen balance of very preterm infants with extrauterine growth restriction.

Wu R, Li LH, Tian ZF, Xu WY, Hu JH, Liu YY. Nitrogen balance of very preterm infants with extrauterine growth restriction. Turk J Pediatr 2019; 61: 352-358. The aim of this study was to investigate the changes of nitrogen balance in preterm infants with extrauterine growth restriction (EUGR) during hospitalization. A total of 64 very preterm infants admitted to the Neonatal Medical Center of Huai`an Maternity and Child Healthcare Hospital were enrolled from May to October 2014. These infants had gestational ages less than 32 weeks and were within 24 hours after birth. The enrolled infants were classified into EUGR (n=18) and non EUGR (n=46) groups according to the discharge weight being below or above the 10th percentile of the expected intrauterine growth for the postmenstrual age. The urinary urea nitrogen of the infants were assayed by the Kjeldahl method and determined at 1st, 7th, 14th and 28th day after birth. Nitrogen balance at each time point was calculated and compared between the EUGR and non EUGR groups. The incidence rate of small for gestational age (SGA) infants (33.3% vs 0.0%) in the EUGR group was higher than that in non EUGR group. The difference was statistically significant (p < 0.05). The birth weight (1.37±0.20 vs 1.63±0.27) and birth weight Z-score (-1.14±0.29 vs-0.37±0.66) in the EUGR group were lower those in non EUGR group. The difference was statistically significant (all p < 0.05). At the 1st, 7th, 14th and 28th day after birth, nitrogen balance values of all infants were negative, showing an upward trend with age. At each observation time point, the nitrogen balance values in the EUGR group were lower than those in non-EUGR group. The differences on the 1st and 28th day between two groups were statistically significant (both p < 0.05), while those on the other time point were not statistically significant (both p > 0.05). All very preterm infants of study were in negative nitrogen balance while the infants of EUGR group had more seriously negative balance.

[Expression of long non-coding RNA NANCI in lung tissues of neonatal mice with hyperoxia-induced lung injury and its regulatory effect on NKX2.1].

OBJECTIVE: To investigate the expression of long non-coding RNA NANCI in lung tissues of neonatal mice with hyperoxia-induced lung injury and its regulatory effect on NKX2.1. METHODS: A total of 48 neonatal C57BL/6J mice were randomly divided into an air group and a hyperoxia group, with 24 mice in each group. Each group was further divided into 7-day, 14-day, and 21-day subgroups, with 8 mice in each subgroup. The mice in the air group were fed in the indoor environment (FiO2=21%) and those in the hyperoxia group were fed in a high-oxygen box (oxygen concentration: >95%). The mice were sacrificed at each time point and lung tissue samples were collected. Hematoxylin and eosin staining was used to observe pathological changes in lung tissues. RT-qPCR and Western blot were used to measure the mRNA and protein expression of NANCI and NKX2.1. RESULTS: The air group had the highest mRNA expression of NANCI and NKX2.1 at 7 days and the same level of mRNA expression at 14 and 21 days. Compared with the air group, the hyperoxia group had significant reductions in the degree of alveolarization and radial alveolar count (RAC) in lung tissues (P<0.05), and in the hyperoxia group, RAC gradually decreased over the time of hyperoxia exposure (P<0.05). The hyperoxia group had significantly lower mRNA and protein expression of NANCI and NKX2.1 than the air group at all time points (P<0.05). In both groups, the relative mRNA and protein expression of NANCI and NKX2.1 gradually decreased over the time of hyperoxia exposure (P<0.05). The expression of NKX2 was positively correlated with that of NANCI (r=0.585, P=0.003), and the expression of NKX2 and NANCI was positively correlated with RAC in the hyperoxia group (r=0.655 and 0.541 respectively, P<0.05). CONCLUSIONS: NANCI may be involved in the development of immature lung tissues. Lung injury is gradually aggravated over the time of hyperoxia exposure. The levels of NANCI and NKX2.1 are associated with the severity of lung injury, suggesting that the NANCI/NKX2.1 target gene signaling pathway might be involved in the development of hyperoxia-induced lung injury in neonatal mice.

The value of pancreatic stone protein in the prediction of infected neonates.

BACKGROUND: The aim of this study was to determine serum pancreatic stone protein (PSP) levels in the neonates with highly probable or probable sepsis and assess their possible value in predicting infected neonates. METHODS: This was a prospective study involving 119 neonates who were admitted with suspected sepsis. The study population was divided into two groups, a infected group (N.=40, with highly probable sepsis or probable sepsis) and control group (N.=79, with possible or no sepsis). The blood samples were obtained at 24, 72 and 168 hours after birth. The amount of serum PSP were detected by enzyme linked immunosorbent (ELISA). RESULTS: PSP serum concentrations were higher in the infected group comparison to the control group at all time points (all P=0.000). In addition the sequential comparison between the infected group and control group at all of time points was significantly different (F=48.558, P=0.000). ROC area under the curve (AUC) was 0.791 [95% CI: 0.71-0.87; P=0.000] for PSP at 24 hours after birth and 0.790 (95% CI: 0.79-0.88; P=0.000) 72 hours after birth and combination of the two time points (24 and 72 hours), the AUC was 0.819 (95% CI: 0.74-0.90; P=0.000). CONCLUSIONS: PSP is a valuable biomarker in predicting infected neonates. Combination of PSP at each time point within 72 hours after birth might be better.

Differential expression of long non-coding RNAs in hyperoxia-induced bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a common complication of premature birth that seriously affects the survival rate and quality of life among preterm neonates. Long non-coding RNAs (lncRNAs) have been implicated in many human diseases. However, the role of lncRNAs in the pathogenesis of BPD remains poorly understood. Here, we exposed neonatal C57BL/6J mice to 95% concentrations of ambient oxygen and established a mouse lung injury model that mimicked human BPD. Next, we compared lncRNA and messenger RNA (mRNA) expression profiles between BPD and normal lung tissues using a high-throughput mouse lncRNA + mRNA array system. Compared with the control group, 882 lncRNAs were upregulated, and 887 lncRNAs were downregulated in BPD lung tissues. We validated some candidate BPD-associated lncRNAs by real-time quantitative reverse-transcription polymerase chain reaction analysis in eight pairs of BPD and normal lung tissues. Gene ontology, pathway and bioinformatics analyses revealed that a downregulated lncRNA, namely AK033210, associated with tenascin C may be involved in the pathogenesis of BPD. To the best of our knowledge, our study is the first to reveal differential lncRNA expression in BPD, which provides a foundation for further understanding of the molecular mechanism of BPD development. Copyright © 2016 John Wiley & Sons, Ltd.

Treatment of neonates with meconium aspiration syndrome by proportional assist ventilation and synchronized intermittent mandatory ventilation: a comparison study.

BACKGROUND: This study aimed to compare the relevant clinical parameters of neonates with MAS who are supported by proportion assisted ventilation (PAV) and synchronized intermittent mandatory ventilation (SIMV). METHODS: Forty neonates diagnosed as MAS who required mechanical ventilation were divided randomly into PAV group and SIMV group (N.=20). The respiratory rate (RR), heart rate (HR), peak inspiratory pressure (PIP), mean arterial blood pressure (MABP), arterial-to-alveolar oxygen tension ratio (a/APO2), fraction of inspiration oxygen (FiO2), mean airway pressure (MAP) and tidal volume (VT) were measured before the ventilation, 1,12, 24, 48 hours after the ventilation and before weaning. RESULTS: We observed no significant differences in the mechanical ventilation time, oxygen supply time, hospital stay between PAV and SIMV groups. In addition, we found no significant differences in HR, MABP, a/APO2 and FiO2 at every time point between two groups (P>0.05). However, we observed significant differences in RR, MAP, PIP and VT at every time point between two groups (P<0.05). CONCLUSIONS: PAV and SIMV might be a useful ventilator mode to support the neonates with MAS who require ventilation. To achieve the same effect, PAV adopts rapid shallow breathing pattern, with smaller tidal volume and lower MAP and PIP.

[Effects of glucocorticoid on RAGE-NF-κB pathway in hyperoxia-induced lung tissues of neonatal rats].

OBJECTIVE: To explore the change of RAGE-NF-κB signaling pathway during the course of hyperoxia-induced lung injury in newborn rats, and the effect of glucocorticoid on this pathway. METHODS: Twenty-four Sprague-Dawley neonatal rats were randomly divided into three groups (n=8 each) : sham control (control group), hyperoxia-induced acute lung injury (model group) and glucocorticoid-treated acute lung injury (glucocorticoid group). Rats were sacrificed at 13 days after birth. RAGE and NF-κB expression levels in lung tissues were detected by reverse transcription polymerase chain reaction, Western blot and immunohistochemistry analysis. The levels of tumor necrosis factor α (TNF-α) and sRAGE in bronchoalveolar lavage fluid (BALF) and serum were measured using ELISA. Lung damage was evaluated by histological examinations. RESULTS: RAGE and NF-κB mRNA and protein expression levels in lung tissues were significantly increased in the model and glucocorticoid groups compared with the control group (P<0.05). Serum RAGE concentrations were significantly increased but RAGE concentrations in BALF were significantly reduced in the model and glucocorticoid groups compared with the control group (P<0.05). RAGE and NF-κB expression at both mRNA and protein levels in lung tissues was significantly lower in the glucocorticoid group than in the model group (P<0.05). RAGE concentrations were significantly lower in serum (P<0.05), but were higher in BALF (P<0.05) in the glucocorticoid group than in the model group. CONCLUSIONS: RAGE-NF-κB pathway plays an important role in hyperoxia-induced lung injury in neonatal rats, and glucocorticoid administration may play a protective role against the lung injury by down-regulating RAGE-NF-κB signaling pathway.

[Biomarkers in acute lung injury].

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is characterized by non-cardiogenic, acute and progressive respiratory failure mediated by a variety of injurious stimuli. ALI can progress to ARDS if an effective management is not taken. The mortality rate remains high due to the complex pathogenesis and ineffective management of ARDS. At present, effective treatment methods for ALI are not available and thus it is important to study the pathogenesis and early diagnosis of ALI. This article reviews some of the biomarkers associated with ALI, with a focus on early diagnosis and future studies.

Shenfu injection attenuates neonatal hypoxic-ischemic brain damage in rat.

Perinatal hypoxia-ischemia remains the most important cause of brain injury in the newborn. However, there is still no effective cure for neonatal hypoxic-ischemic brain damage (HIBD). In the present study, we aimed to examine the neuroprotective effects of Shenfu injection (SFI) on HIBD of neonatal rat. Sprague-Dawley rats were divided randomly into three groups (n = 8): S group: the rats were sham operated; C group: the rats were operated for HIBD modeling and received intraperitoneal injection of saline; SFI group: the rats were operated for HIBD modeling and received intraperitoneal injection of SFI (10 ml/kg days) for 7 days. Flow cytometry analysis showed that apoptosis rate of neuron in hippocampal CAI region in SFI group was significantly less than in NC group at 3 and 7 days after HI insult (P < 0.05). Immunohistochemical staining demonstrated that Bcl-2 expression was markedly higher while Bax expression was significantly lower in SFI group than in the C group at 24, 72 h and 7 days after HI insult (P < 0.05). Our findings suggest that SFI exhibits neuroprotective effects for neonatal hypoxic-ischemic brain injury by preventing neuron apoptosis and has potential to be used in the clinical for the treatment of perinatal hypoxia-ischemia.

[Influence of human mesenchymal stem cells on hyperoxia-exposed newborn rats by RAGE-NF-κB signaling in lung].

OBJECTIVE: To investigate the influence of high oxygen exposure on signaling pathway of the receptor for advanced glycation end products (RAGE)-NF-κB of lung in newborn rats and the mechanisms of protecting lung injury for human mesenchymal stem cells (hMSC). METHODS: Twenty-four newborn Sprague-Dawley rats from three litters were randomly divided into three groups, as hyperoxia exposed + hMSC group (group A), hyperoxia exposed group (group B), and air-exposed group (group C). The rats from the group A and B were placed in a sealed Plexiglas chamber with a minimal in-and outflow, providing six to seven exchanges per hour of the chamber volume and maintaining O(2) levels above 95%, while rats in the group C only exposed to air simultaneously. Seven days later, rats in the group A were injected intravenously with hMSC (5×10(4)) after hyperoxia exposure, but rats in group B and C received subcutaneous injection with PBS alone at the same time point. Then all the rats were exposed to air, and were sacrificed three days later. Immunohistochemistry was used to evaluate the expression of RAGE in lung tissue. The levels of TNF-α and sRAGE in bronchoalveolar lavage fluid (BALF) and in serum were detected by ELASA, RAGE mRNA and NF-κB mRNA in tissue homogenates were detected by RT-PCR, RAGE and NF-κB by Western blotting; also the value of lung damage score were calculated with histology under light microscope. RESULTS: There were significant differences among three groups in the fields of lung damage score (F = 51.59, P = 0.000), mRNA and protein of RAGE (F = 37.21, P = 0.000; F = 15.88, P = 0.000) and NF-κB (F = 5.695, P = 0.011; F = 4.223, P = 0.0288) in lung tissue homogenates, and the level of TNF-α (F = 38.29, P = 0.000) in BALF, all these parameters in group A and group B were higher than that in group C. While sRAGE in BALF in group A and group B were less than that in group C (F = 4.804, P = 0.0191). There were also significant differences between group A and group B in these parameters (P < 0.05). There were also no significant differences neither in TNF-α nor in sRAGE in serum among three groups. CONCLUSIONS: hMSC protects hyperoxia-induced lung injury via downregulating the signaling pathway of RAGE-NF-κB.

[Expression of erythropoietin and its receptor in the brain of newborn rats suffering from fetal distress].

OBJECTIVE: To study the expression of erythropoietin (EPO) and its receptor (EPOR) in the brain of newborn rats suffering fetal distress. METHODS: A model of fetal distress was prepared by ligating bilateral uterine arteries of the rats with full-term pregnancy for 10 minutes before cesarean sections. The expression levels of EPO and EPOR in the brain of newborn rats were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot at 0, 2, 6, 12, 24, 48, 72 hrs and 7 days after birth. Serum EPO levels were measured using ELISA simultaneously. The newborn rats born by cesarean sections which were not subjected to uterine artery ligation were used as the control group. RESULTS: The expression of EPO protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6 and 12 hrs after birth (P<0.05). The expression of EPOR protein and mRNA in brain tissues in the fetal distress group increased significantly compared with the control group 2, 6, 12, 24 and 48 hrs, and 3 days after birth (P<0.05). Serum EPO levels in the fetal distress group were significantly higher than in the control group 2 hrs after birth. CONCLUSIONS: The EPO and EPOR levels in the brain increase quickly after birth in newborn rats suffering from fetal distress. The EPOR is high expressed for a longer time than EPO. This can provide a basis for the treatment of neonatal brain damage induced by fetal distress by exogenous EPO.

[Protection of hyperoxia-induced lung injury by granulocyte-macrophage colony-stimulating factor via RAGE-NF-κB signaling pathway in newborn rats].

OBJECTIVE: To explore the effects of granulocyte-macrophage colony-stimulating factor (GMCSF) on hyperoxia exposure lung injury in newborn rats and elucidate its protective mechanism of operating via the signaling pathway of advanced glycation end products (RAGE)-NF-κB. METHODS: Twenty-four 3-day-old SD rats from 3 litters were randomly divided into 3 groups. They were hyperoxia exposure plus GMCSF group (group A), hyperoxia exposure group (group B) and air exposure group (group C). The rats from groups A and B were placed in a sealed Plexiglas chamber with a minimal in-and-outflow, providing 6 - 7 exchanges per hour of chamber volume and maintaining O(2) levels above 95%. While the rats in group C only were exposed to air simultaneously. The rats in group A received subcutaneous injections of recombinant murine GMCSF (9 µg/kg) during hyperoxia exposure at 24 h, 72 h and 120 h respectively. And the rats in groups B and C received subcutaneous injections of saline vehicle alone at the same time point. Seven days later, all were sacrificed and immunohistochemistry was employed to assess the expression of RAGE in lung tissue. The levels of tumor necrosis factor-α in bronchoalveolar lavage fluid (BALF) and serum samples were detected by ELISA (enzyme-linked immunosorbent assay). The RAGE mRNA and NF-κB mRNA in tissue homogenates were detected by RT-PCR while RAGE and NF-κB by Western blot. Also the values of lung damage score were calculated with microscopic histology. RESULTS: The value of lung damage score in group C, B and A was 0.46 ± 0.20, 3.06 ± 0.33 and 2.31 ± 0.56 respectively, there was significantly difference among three groups (P = 0.000). The expression of RAGE mRNA and protein in three groups were 0.14 ± 0.02, 0.34 ± 0.06, 0.28 ± 0.04 and 0.30 ± 0.04, 0.76 ± 0.11, 0.55 ± 0.08 respectively. There were both significantly differences among three groups (P = 0.000, P = 0.000). The expression of NF-κB mRNA and protein in three groups were 0.41 ± 0.21, 0.90 ± 0.36, 0.69 ± 0.30 and 0.41 ± 0.26, 0.96 ± 0.43, 0.77 ± 0.33 respectively, there were both significantly difference among three groups (P = 0.000, P = 0.017). The level of TNF-α in BALF was 76 ± 10, 224 ± 42 and 143 ± 24 respectively, there was significantly difference among three groups (P = 0.000). All indicators above in group B and group A were significantly more than those in group C (all P < 0.05), while these indicators in group A were lower than those in group B. But there was no difference in the level of TNF-α of serum among three groups (P > 0.05). CONCLUSION: GMCSF may protect hyperoxia-induced lung injury via down-regulating the signaling pathway of RAGE-NF-κB.

[Effect of continuous blood purification on plasma cytokines in children with severe sepsis].

OBJECTIVE: To explore the influence of continuous blood purification (CBP) on plasma cytokines in children with severe sepsis. METHODS: A double lumen catheter was inserted into the femoral vein of 21 children with severe sepsis, and CBP was performed using the Baxter BM25 system. Blood urea nitrogen (BUN), plasma creatinine (Cr), K(+) and arterial blood gas were measured before and after CBP, and the plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), IL-6, IL-8, and IL-10 were measured by ELISA at 0, 1, 3, 6, and 24 h after CBP. RESULTS: BUN and plasma Cr and K(+) levels decreased and HCO(3)(-)increased significantly after CBP (P<0.001), which also resulted in significant reduction of the plasma concentrations of TNF-alpha, IL-1, IL-8 and IL-10 (P<0.01). The plasma TNF-alpha, IL-1, and IL-8 levels were significantly lower at 3 h after CBP than those before CBP (P<0.01). CONCLUSIONS: CBP can improve the blood biochemical markers and clear some plasma cytokines in children with severe sepsis.

[Preliminary study on maturity of retinal vascularization in premature infants].

OBJECTIVE: To study the extent of retinal vascular development and influencing factors at birth and the relation between retinal vascularization and retinopathy of prematurity (ROP). METHODS: From October, 2006 to December 2006, retinal vascularization was screened and evaluated in 84 neonates at different weeks of gestation and birth weights (BWs), had dilated fundus evaluation for zone of retinal vascularization by the 130 degrees lens of a digital fundus camera. The infants' pupils were dilated with 2.5% phenylephrine and 0.5% cyclopentolate eye drops. The study cohort was divided into subgroups depending on the weeks of gestation and birth weights. The control group consisted of healthy term infants. Maternal and neonatal factors were ascertained and analysed. RESULTS: Vascularization up to zone I and II was considered to be immature retina; vascularization up to zone III or beyond was considered to be mature retina. In this study, 11 of 12 infants who were born at < 30 weeks of gestation, 12 of 26 infants who were born at < 31 approximately 33 weeks of gestation, 1 of 26 babies who were born at < 34 approximately 36 weeks of gestation and none of 20 babies who were born at < 37-40 weeks of gestation had immature retina; 12 of 15 babies at < 1500 g BW, 8 of 14 infants at 1500 g < BW < 1700 g, 4 of 11 infants at 1700 g < BW < 2000 g and of 44 infants at > 2000 g BW had immature retina. Those infants who were born at > 34 weeks of gestational age and at > 2000 g BW had mature retina. Infants who were born between 31 to 34 weeks of gestation and at 1501 to 2000 g BW had variable extent of retinal vascularization at birth. Vascularization was associated with postconceptional age (F = 31.9193, P = 0.000), birth weight (F = 32.4532, P = 0.000), anemia (F = 36.9391, P = 0.000), surfactant (F = 24.000, P = 0.0000), poor nutrition (F = 4.184, P = 0.041), RDS (F = 17.6191, P = 0.000), cesarean delivery (F = 10.972, P = 0.0022) and oxygen > 48 h (F = 22.076, P = 0.0000). Vascularization was affected mainly by the postconceptional age (95% CI = 1.57-261.728, P = 0.021). At last, 15/24 infants with immature retina developed ROP while none of the infants with mature retina developed ROP (chi2 = 45.1087, P = 0.000). CONCLUSION: There is considerable variability in the extent of retinal vascularization in infants who we born between 31 to 34 weeks of gestation. Modifiable maternal and fetal factors could influence extent of vascularization at birth. Immature retina is the critical factor of ROP. Gestational age is the main factor of the immature retina in premature infants.

[Marrow-derived mesenchymal stem cells protect the lung injury caused by exposure to high oxygen: experiment with rats].

OBJECTIVE: To investigate the influence of marrow-derived mesenchymal stem cells (MSCs) on the lung injury caused by exposure to high oxygen. METHODS: MSCs were extracted from the femurs of Sprague-Dawley (SD) rat, cultured, amplified, and labeled with 5-bromo-2'-deoxy-uridine (BrdU). Thirty-two 3-day-old SD rats were randomly divided into 4 equal groups: Group A, exposed to high oxygen (95%) for 7 days and then injected intra-peritoneally with 50 microl phosphate buffered solution (PBS) containing 5 x 10(4) MSCs; Group B, exposed to ordinary air for 7 days and then injected intra-peritoneally with PBS containing 5 x 10(4) MSCs; Group C, exposed to high oxygen (95%) for 7 days and then injected intra-peritoneally with PBS without MSC; and Group D, exposed to ordinary air for 7 days and then injected intra-peritoneally with PBS without MSC. 72 h later, when the rats were 13 days old they were killed Bronchoalveolar lavage fluid (BALF) was obtained to count the numbers of white blood cells and neutrophils. Lung homogenate was made. ELISA was used to examine the contents of tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Radial alveolar count (RAC) of the lungs was conducted under light microscope. Double-staining immunocytochemistry was used to detect the expression of surfactant protein A (SP-A) and BrdU. RESULTS: (1) The RAC values of Groups A and C were (11.0 +/- 1.0) and (9.6 +/- 0.7) cells/10 fields, both significantly lower than those of Group B and D [(13.9 +/- 1.1) and (14.0 +/- 1.1) cells/10 fields respectively, F = 40.41, P = 0.000]. The RAC of Group A was significantly higher than that of Group C (P < 0.05). (2) The white blood cell numbers in BALF of Groups A and C were (0.85 +/- 0.21) and (1.44 +/- 0.69) x 10(5)/ml respectively, both significantly higher than those of Groups B and D [(0.18 +/- 0.10) and (0.21 +/- 0.06) x 10(5)/ml respectively, F = 21.52, P = 0.000]. The neutrophil numbers of Groups A and C were (0.32 +/- 0.12) and (0.73 +/- 0.35) x 10(5)/ml respectively, both significantly higher than those of Groups B and D [(0.06 +/- 0.02) and (0.07 +/- 0.02) x 10(5)/ml respectively, F = 22.91, P = 0.000]. (3) The TNF-alpha levels in the homogenate of Groups A and C were (173 +/- 20) and (224 +/- 42) pg/m respectively, both significantly higher than those of Group B and D [(34 +/- 4) and (35 +/- 4) pg/ml respectively, F = 138.1, P = 0.000]. The IL-1beta levels in the homogenate of Groups A and C were (530 +/- 74) and (948 +/- 82) pg/ml respectively, both significantly higher than those of Group B and D [(210 +/- 33) and (216 +/- 30) pg/ml respectively, F = 247.4, P = 0.000]. (4) BrdU-positive cells and SP-A-positive cells were seen in both Groups A and B, a few double-stained cells were found in Group A, but only SP-A-positive cells, and none BrdU positive cells and double-stained cells were seen in Groups C and D. CONCLUSION: MSC administration has protective effect on the ling injury caused by exposure to high oxygen via different mechanisms.

[Influence of human bone marrow-derived mesenchymal stem cells on the lung of newborn rats damaged by hyperoxia].

OBJECTIVE: To evaluate whether human mesenchymal stem cells (hMSCs) administration alter the clinical course of hyperoxia-induced lung injury. METHODS: hMSCs were obtained from bone marrow aspirates from healthy donors after informed consent was signed, hMSCs were separated, cultured, amplified, identified and labeled with BrdU. For BrdU labeling, a sterile stock solution was added to the culture medium 48 h before the end of culture, at a final concentration of 10 micromol/L. Thirty-two 3-day old SD rats from four litters were randomly divided into four groups, as hyperoxia exposed + hMSC group (A), air-exposed + hMSC group (B), hyperoxia exposed group (C), and air-exposed group (D). The rats from the group A and the group C were placed in a sealed Plexiglas chamber with a minimal in- and outflow, providing six to seven exchanges per hour of the chamber volume and maintaining O2 levels above 95%, while the rats in the group B and the group D were only exposed to room air. Seven days later, all of them were taken out of the chamber, rats in the group A and B were injected intraperitoneally with hMSCs (1 x 10(5) in 50 microl of PBS) immediately, while the rats in the group C and D were only treated with 50 microl of PBS 3 days later. All the animals were sacrificed by an injection of sodium pentobarbital (120 mg/kg), perfused with cold 0.9% NaCl, and the left lungs were removed, the upper lobes of which were ground as tissue homogenates and used for ELISA, while the inferior lobes were stored at -70 degrees C until use for RT-PCR. The right lungs were fixed in situ for 2 h by the intratracheal instillation with 10% neutral formalin and then postfixed for 24 h. Sagittal sections (4-microm) of paraffin-embedded middle lobe and upper lobe of the right lung were used for immunohistochemistry and histology, respectively. RESULTS: (1) There was a significant difference in the value of RAC (raditive alveoli coant) among the 4 groups (11.145 +/- 1.331, 13.941 +/- 0.985, 9.595 +/- 0.672, 14.819 +/- 1.080, F = 43.234, P = 0.000). RAC in group A and C were significantly reduced compared with subjects in group D (P < 0.05, P < 0.05); and there was also a significant difference between group A and group C (P < 0.05), but not between group B and D subjects (P > 0.05). (2) There were significant differences in the levels of both TNFalpha and TGFbeta(1) in the homogenate of lungs among the 4 groups (142.933 +/- 24.017, 79.033 +/- 11.573, 224.088 +/- 41.915, 76.500 +/- 10.373, F = 59.970, P = 0.000; 1726.484 +/- 91.086, 1530.359 +/- 173.441, 2047.717 +/- 152.057, 1515.777 +/- 131.049, F = 24.977, P = 0.000). The levels of TNFalpha and TGFbeta1 were significantly elevated in both group A and group C when compared with subjects in group D (P < 0.05 for both). Concentrations of TNFalpha and TGFbeta1 were both significantly decreased in group A versus group C (P < 0.05 for both). There was no significant difference between group B and D subjects in the fields of TNFalpha and TGFbeta(1) (P > 0.05 for both). (3) BrdU-labelled cells were observed at alveolar wall and bronchioles in both group A and group B, and there was a significant difference in BrdU-labeled cells between two groups (0.230 +/- 0.026, 0.190 +/- 0.015; t = 3.769, P = 0.002), but none was found in group C and group D. Electrophoresis of the PCR products showed a 224 bp band, specific for Alu mRNA, in 7 of 8 rats of group A and 5 of 8 rats of group B, respectively, but no such band was found in group C and group D. CONCLUSION: hMSCs administered by intraperitoneal injection could be implanted in the lungs of newborn rats, and they could effectively protect the rats against damage to the lungs caused by hyperoxia.

[Intravenous infusion of rat bone marrow-derived mesenchymal stem cells ameliorates hyperoxia-induced lung injury in neonatal rats].

OBJECTIVE: To investigate the effect of intravenous infusion of rat bone marrow-derived mesenchymal stem cells (MSCs) against lung injuries in neonatal exposed to hyperoxia. METHODS: Rat bone marrow-derived MSCs were separated, cultured, amplified, and labeled with BrdU. Thirty-two 3-day-old SD rats were randomized into 4 equal groups (groups A, B, C and D), and the rats in groups A and B were exposed to 7-day 95% oxygen, while those in groups C and D were not. In groups A and C, the rats received injection with 5x10(4) MSCs via the tail vein, and those in groups B and D were given PBS only. Seventy-two hours after housing in normal air, all the rats were killed to determine the radial alveolar count (RAC) under light microscope. Immunohistochemistry was used to detect BrdU expression in the lung tissue, where the levels of tumor necrosis factoralpha(TNFalpha) and transforming growth factor beta1 (TGFbeta1) were detected using enzyme-linked immunosorbent assay. RESULTS: Compared to air exposure groups, the levels of TNFalpha and TGFbeta1 in the homogenate of the lungs increased while RACs decreased significantly in the two hyperoxia exposure groups. Groups A and B showed significant differences in the fields of RACs and the levels of TNFalpha and TGFbeta1 in the lung tissue homogenate, and BrdU-positive cells were detected only in the lungs of groups A and C, between which a significant quantitative difference was seen. CONCLUSION: Intravenously injected MSCs may reside in the lungs of neonatal rats, which is subject to influences by the exposure conditions, and the transplanted MSCs may offer effective protection against lung injuries induced by hyperoxia.