BackgroundIntrauterine infection/inflammation plays an important role in the development of lung injury and bronchopulmonary dysplasia (BPD) in preterm infants, While a multifactorial genesis is likely, mechanisms involved in BPD after intrauterine infection/inflammation are largely unknown. Recent studies have suggested microRNAs (miRNAs) are likely to play a role. Therefore, this study aimed to study the effects and mechanisms of intrauterine infection/inflammation on lung development, and to identify miRNAs related to lung injury and BPD.MethodsAn animal model of intrauterine infection/inflammation was established with pregnant SD rats endocervically inoculated with E.coli. The fetal and neonatal rats were observed at embryonic day (E) 17, 19, 21 and postnatal day (P) 1, 3, 7, 14, respectively. Body weight, lung weight, the expression levels of NLRP3, TNF-α, IL-lβ, IL-6, VEGF, Collagen I, SP-A, SP-B and SP-C in the lung tissues of fetal and neonatal rats were measured. Expression profiles of 1218 kinds of miRNAs in the lungs of neonatal rats were detected by miRNA microarray technique. Target genes of the identified miRNAs were predicted through online software.ResultsIntrauterine infection/inflammation compromised not only weight development but also lung development of the fetal and neonatal rats. The results showed significantly increased expression of NLRP3, TNF-α, IL-1β, IL-6, Collagen I, and significantly decreased expression of VEGF, SP-A, SP-B and SP-C in the fetal and neonatal rat lung tissues in intrauterine infection group compared to the control group at different observation time point (P < 0.05). Forty-three miRNAs with significant differential expression were identified. Possible target genes regulated by the identified miRNAs are very rich.ConclusionsIntrauterine infection/inflammation results in lung histological changes which are very similar to those observed in BPD. Possible mechanisms may include NLRP3 inflammasome activation followed by inflammatory cytokines expression up-regulated, inhibiting the expression of pulmonary surfactant proteins, interfering with lung interstitial development. There are many identified miRNAs which target a wide range of genes and may play an important role in the processes of lung injury and BPD.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0787-y) contains supplementary material, which is available to authorized users.

Heat stress causes many pathophysiological responses in the brain, including neuroinflammation and cognitive deficits. β‐Hydroxybutyric acid (BHBA) has been shown to have neuroprotective effects against inflammation induced by lipopolysaccharide. The aim of the present study was to evaluate the effects of BHBA on neuroinflammation induced by heat stress, as well as the underlying mechanisms. Mice were pretreated with vehicle, BHBA or minocycline (positive control group) and followed by heat exposure (43°C) for 15 min for 14 days. In mice subjected to heat stress, we found that treatment with BHBA or minocycline significantly decreased the level of serum cortisol, the expressions of heat shock protein 70 (HSP70), and the density of c‐Fos+ cells in the hippocampus. Surprisingly, the ethological tests revealed that heat stress led to cognitive dysfunctions and could be alleviated by BHBA and minocycline administration. Further investigation showed that BHBA and minocycline significantly attenuated the activation of microglia and astrocyte induced by heat stress. Pro‐inflammatory cytokines were attenuated in the hippocampus by BHBA and minocycline treatment. Importantly, compared with the heat stress group, mice in the BHBA treatment group and positive control group experienced a decrease in the expressions of toll‐like receptor 4 (TLR4), phospho‐p38 (p‐p38), and nuclear factor kappa B (NF‐κB). Our results elucidated that BHBA inhibits neuroinflammation induced by heat stress by suppressing the activation of microglia and astrocyte, and modulating TLR4/p38 MAPK and NF‐κB pathways. This study provides new evidence that BHBA is a potential strategy for protecting animals from heat stress.

Scope: This study aims to investigate the role of gut microbiota regulation with ketogenic diet (KD) in hypoglycemia-induced neuroinflammation. Methods and results: Immunofluorescence staining and western blotting show that KD alleviates blood-brain barrier injury induced by hypoglycemia by increasing Podxl and zonula occludens-1 (ZO-1) levels. KD-fed mice show reduced brain edema by decreasing aquaporin-4 (AQP4) content and maintaining its polarized expression. 16S rRNA gene amplicon sequencing results show that KD reduces the Chao 1 index of gut microbiota 𝜶-diversity, and significant separation is detected in the 𝜷-diversity analysis between the control and KD-fed mice. KD increases the relative abundance of Firmicutes and Proteobacteria and decreases that of Bacteroidetes. Hypoglycemia can reduce SOD and GSH-PX levels while increasing TNF-𝜶, IL-1𝜷, and IL-6 mRNA levels in the brain tissues of mice. KD alleviates hypoglycemia-induced neuroinflammation by inhibiting microglia activation and TLR4/p38MAPK/NF-𝜿B signaling pathway. Importantly, antibiotic cocktail depletion of the gut microbiota weakens anti-inflammatory and antioxidation responses in KD-fed mice. Conclusion: Collectively, these findings suggest that KD alleviates hypoglycemia-induced brain injury via gut microbiota modulation, which may provide novel insights into the therapy for hypoglycemia.

Background To investigate the impact of the coronavirus disease 2019 (COVID-19) pandemic on hospitalizations for neonatal infectious diseases. Methods We analyzed data for neonatal inpatients admitted at a tertiary academic hospital with a principal diagnosis of an infectious disease during January 2015 to December 2020. We compared hospitalizations in 2020 (COVID-19 cohort), corresponding with the impact of COVID-19 pandemic and associated containment measures, and the comparable 2015 to 2019 (pre-COVID-19 cohort). Results 14,468 cases admitted for neonatal infectious diseases were included in our study, with 1201 cases in the COVID-19 cohort and 13,267 cases in the pre-COVID-19 cohort. The leading causes of hospitalizations for neonatal infectious diseases remain being respiratory tract infections (median ratio = 0.461, 95% CI 0.335–0.551), sepsis (median ratio = 0.292, 95% CI 0.263–0.361), gastric intestinal infections (median ratio = 0.095, 95% CI 0.078–0.118) and dermatologic infections (median ratio = 0.058, 95% CI 0.047–0.083). The seasonality of neonatal infectious disease hospitalizations could be obviously observed, with the total number and the overall rate of hospitalizations for neonatal infectious diseases in the first and fourth quarters greater than that of hospitalizations for neonatal infectious diseases in the second and third quarters in each year (1362.67 ± 360.54 vs 1048.67 ± 279.23, P = 0.001; 8176/20020 vs 6292/19369, P < 0.001, respectively). Both the numbers and the proportions of hospitalizations for neonatal infectious diseases in different quarters of the COVID-19 cohort significantly decreased as compared with those forecasted with the data from the pre-COVID-19 cohort: the numbers per quarter (300.25 ± 57.33 vs 546.64 ± 100.43, P-value = 0.006), the first quarter (0.34 vs 0.40, P = 0.002), the second quarter (0.24 vs 0.30, P = 0.001), the third quarter (0.24 vs 0.28, P = 0.024), and the fourth quarter (0.29 vs 0.35, P = 0.003). Conclusions Despite the outbreak of the COVID-19 pandemic, the leading causes of hospitalizations for neonatal infectious diseases remain unchanged. The seasonality of neonatal infectious disease hospitalizations could be obviously observed. The numbers as well as the overall rates of hospitalizations for neonatal infectious diseases in the COVID-19 cohort dramatically declined with the impact of the COVID-19 pandemic and its mitigation measures.

Objective To evaluate the efficacy and safety of intravenous immunoglobulin G (IVIG) in infants with ABO hemolytic disease of the newborn (HDN). Methods Infants with moderate-to-severe ABO HDN during early neonatal period (<7 days) at our hospital in 2017 were included in this retrospective study. Patients treated with IVIG and phototherapy were classified as the IVIG group, and those who only received phototherapy were classified as the phototherapy only group. Results Forty-six patients were classified into the IVIG group and 68 other patients were classified into the phototherapy only group. There was no significant difference in duration of phototherapy, hospitalization periods, needs for exchange transfusion, transfusions, and incidence of bilirubin-induced neurological sequelae between these two groups (P = 0.20, 0.27, 0.65, 0.47, 0.78, respectively). Conclusion It seems unnecessary to expose neonates to IVIG in moderate-to-severe ABO HDN when the available data show no appreciable benefits.