Adrenomedullin Deficiency Potentiates Lipopolysaccharide-Induced Experimental Bronchopulmonary Dysplasia in Neonatal Mice

Changes in adrenomedullin in bronchoalveolar lavage fluid with chorioamnionitis in a sheep-based model

BACKGROUND

Adrenomedullin (AM) is a potent angiogenic, antioxidant and anti-inflammatory peptide protecting the developing lung from injury due to bronchopulmonary dysplasia (BPD) of the preterm infant. At this stage, no data on the potential effects of chorioamnionitis (CA) occurrence and glucocorticoids (GC) administration on AM in developing lungs are still lacking.

OBJECTIVE

to investigate, in a sheep-based model, the positive/side-effects of combined exposure to CA and GC on AM concentrations measured in bronchoalveolar lavage fluid (BALF).

METHODS

Time-mated ewes were randomly admitted to one of six treatment groups receiving injection: saline (controls); lipopolysaccharide (L) in intra-amniotic fluid treated alone at 7 or 14 d before delivery or associated with betamethasone (B) intramuscularly; B treated alone (7d) or associated with L (14d). Lambs were surgically delivered at 120 days gestation and euthanized. BALF was used for AM measurement in the studied groups.

RESULTS

AM BALF levels significantly (p < 0.05, for all) changed both to B and L exposure in a time-dependent manner. The latter was characterized by AM levels at short term superimposable to controls, whilst significantly (p > 0.05) decreased at long-term. The former showed increased AM at short and decreased at long-term (p < 0.05, for all), respectively.

CONCLUSIONS

the present results showing AM BALF changes in a sheep-based model support the AM role in the hemodynamic patterns due to CA and BPD occurrence and open the way to further studies investigating the role of vasoactive agents as trustable markers of lung development/damage.

Proteomic analysis of premature umbilical cord blood and its relationship with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) frequently occurs in preterm infants, causing significantly impaired lung function and increased mortality rates. Studies on plasma protein levels can facilitate early detection of BPD, enabling prompt intervention and a decrease in mortality.

METHODS

We conducted a prospective observational study involving proteomic sequencing of plasma samples from 19 preterm infants. Our analysis included principal component analysis, volcano plots, heatmap analysis, enrichment analysis, and receiver operating characteristic (ROC) analysis.

RESULTS

Infants with BPD were characterized by increased levels of lipopolysaccharide (LPS)-binding protein (LBP), X-ray repair cross-complementing protein 6 (XRCC6), GLI pathogenesis-related 1 (GLIPR1), Golgi membrane Protein 1(GOLM1), immunoglobulin kappa variable (IGKV1-5), and immunoglobulin kappa variable 1-33 (IGKV1-33) in cord blood. Additionally, gene pathway analysis revealed a significant correlation between the pathways associated with these genes and BPD, particularly pathways involved in the immune system, innate immune system, neutrophil degranulation, prion diseases, regulation of the actin cytoskeleton, and the MAPK signaling. The proteins amine oxidase copper containing 3 (AOC3) and H4 clustered histone 6 (H4C6) were diagnostically significant. Additionally, H4C6 was negatively correlated with intraventricular haemorrhage and patent ductus arteriosus, and positively correlated with antenatal steroid administration. AOC3 was also positively correlated with antenatal steroid use.

CONCLUSIONS

Our findings suggest that the development of BPD is associated with changes in the plasma proteome of preterm infants. Specifically, the levels of AOC3 and H4C6 in the bloodstream could serve as biomarkers for the early detection of BPD in preterm infants. Furthermore, we found that GOLM1, lipopolysaccharide (LPS)-binding protein, XRCC6, and the contribution of neutrophil degranulation may play a crucial role in the development of therapies for BPD.

Grimm S, Coarfa C, Theis F, Simon LM, Shivanna B. Leveraging Integrated RNA Sequencing to Decipher Adrenomedullin's Protective Mechanisms in Experimental Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease commonly affecting premature infants, with limited therapeutic options and increased long-term consequences. Adrenomedullin (Adm), a proangiogenic peptide hormone, has been found to protect rodents against experimental BPD. This study aims to elucidate the molecular and cellular mechanisms through which Adm influences BPD pathogenesis using a lipopolysaccharide (LPS)-induced model of experimental BPD in mice. Bulk RNA sequencing of Adm-sufficient (wild-type or Adm+/+) and Adm-haplodeficient (Adm+/-) mice lungs, integrated with single-cell RNA sequencing data, revealed distinct gene expression patterns and cell type alterations associated with Adm deficiency and LPS exposure. Notably, computational integration with cell atlas data revealed that Adm-haplodeficient mouse lungs exhibited gene expression signatures characteristic of increased inflammation, natural killer (NK) cell frequency, and decreased endothelial cell and type II pneumocyte frequency. Furthermore, in silico human BPD patient data analysis supported our cell type frequency finding, highlighting elevated NK cells in BPD infants. These results underscore the protective role of Adm in experimental BPD and emphasize that it is a potential therapeutic target for BPD infants with an inflammatory phenotype.

Molecular mechanisms of cell death in bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) in neonates is the most common pulmonary disease that causes neonatal mortality, has complex pathogenesis, and lacks effective treatment. It is associated with chronic obstructive pulmonary disease, pulmonary hypertension, and right ventricular hypertrophy. The occurrence and development of BPD involve various factors, of which premature birth is the most crucial reason for BPD. Under the premise of abnormal lung structure and functional product, newborns are susceptible to damage to oxides, free radicals, hypoxia, infections and so on. The most influential is oxidative stress, which induces cell death in different ways when the oxidative stress balance in the body is disrupted. Increasing evidence has shown that programmed cell death (PCD), including apoptosis, necrosis, autophagy, and ferroptosis, plays a significant role in the molecular and biological mechanisms of BPD and the further development of the disease. Understanding the mode of PCD and its signaling pathways can provide new therapeutic approaches and targets for the clinical treatment of BPD. This review elucidates the mechanism of BPD, focusing on the multiple types of PCD in BPD and their molecular mechanisms, which are mainly based on experimental results obtained in rodents.