Inflammatory blockade prevents injury to the developing pulmonary gas exchange surface in preterm primates.

Perinatal inflammatory stress is associated with early life morbidity and lifelong consequences for pulmonary health. Chorioamnionitis, an inflammatory condition affecting the placenta and fluid surrounding the developing fetus, affects 25 to 40% of preterm births. Severe chorioamnionitis with preterm birth is associated with significantly increased risk of pulmonary disease and secondary infections in childhood, suggesting that fetal inflammation may markedly alter the development of the lung. Here, we used intra-amniotic lipopolysaccharide (LPS) challenge to induce experimental chorioamnionitis in a prenatal rhesus macaque (Macaca mulatta) model that mirrors structural and temporal aspects of human lung development. Inflammatory injury directly disrupted the developing gas exchange surface of the primate lung, with extensive damage to alveolar structure, particularly the close association and coordinated differentiation of alveolar type 1 pneumocytes and specialized alveolar capillary endothelium. Single-cell RNA sequencing analysis defined a multicellular alveolar signaling niche driving alveologenesis that was extensively disrupted by perinatal inflammation, leading to a loss of gas exchange surface and alveolar simplification, with notable resemblance to chronic lung disease in newborns. Blockade of the inflammatory cytokines interleukin-1ß and tumor necrosis factor-α ameliorated LPS-induced inflammatory lung injury by blunting stromal responses to inflammation and modulating innate immune activation in myeloid cells, restoring structural integrity and key signaling networks in the developing alveolus. These data provide new insight into the pathophysiology of developmental lung injury and suggest that modulating inflammation is a promising therapeutic approach to prevent fetal consequences of chorioamnionitis.

A potent myeloid response is rapidly activated in the lungs of premature Rhesus macaques exposed to intra-uterine inflammation.

Up to 40% of preterm births are associated with histological chorioamnionitis (HCA), which leads to elevated levels of pro-inflammatory mediators and microbial products in the amniotic fluid, which come in contact with fetal lungs. Yet, fetal pulmonary immune responses to such exposure remain poorly characterized. To address this gap, we used our established HCA model, in which pregnant Rhesus macaques receive intraamniotic (IA) saline or LPS. IA LPS induced a potent and rapid myeloid cell response in fetal lungs, dominated by neutrophils and monocytes/macrophages. Infiltrating and resident myeloid cells exhibited transcriptional profiles consistent with exposure to TLR ligands, as well as cytokines, notably IL-1 and TNFα. Although simultaneous, in vivo blockade of IL-1 and TNFα signaling did not prevent the inflammatory cell recruitment, it blunted the lung overall inflammatory state reducing communication between, and activation of, infiltrating immune cells. Our data indicate that the fetal innate immune system can mount a rapid multi-faceted pulmonary immune response to in utero exposure to inflammation. These data provide mechanistic insights into the association between HCA and the postnatal lung morbidities of the premature infant and highlight therapeutic potential of inflammatory blockade in the fetus.

Timing of antimicrobial prophylaxis for cesarean section is critical for gut microbiome development in term born infants.

Animal models imply that the perinatal exposure to antibiotics has a substantial impact on microbiome establishment of the offspring. We aimed to evaluate the effect of timing of antimicrobial prophylaxis for cesarean section before versus after cord clamping on gut microbiome composition of term born infants. We performed an exploratory, single center randomized controlled clinical trial. We included forty pregnant women with elective cesarean section at term. The intervention group received single dose intravenous cefuroxime after cord clamping (n = 19), the control group single dose intravenous cefuroxime 30 minutes before skin incision (n = 21). The primary endpoint was microbiome signature of infants and metabolic prediction in the first days of life as determined in meconium samples by 16S rRNA gene sequencing. Secondary endpoints were microbiome composition at one month and 1 year of life. In meconium samples of the intervention group, the genus Staphylococcus pre-dominated. In the control group, the placental cross-over of cefuroxime was confirmed in cord blood. A higher amino acid and nitrogen metabolism as well as increased abundance of the genera Cutibacterium, Corynebacterium and Streptophyta were noted (indicator families: Cytophagaceae, Lactobacilaceae, Oxalobacteraceae). Predictive models of metabolic function revealed higher 2'fucosyllactose utilization in control group samples. In the follow-up visits, a higher abundance of the genus Clostridium was evident in the intervention group. Our exploratory randomized controlled trial suggests that timing of antimicrobial prophylaxis is critical for early microbiome engraftment but not antimicrobial resistance emergence in term born infants.

Infants Younger Than 90 Days Admitted for Late-Onset Sepsis Display a Reduced Abundance of Regulatory T Cells.

Objective: To provide epidemiological data of infants < 90 days of age with suspected late-onset sepsis (LOS) and evaluate distinct immunological specificities. We hypothesized that previously healthy infants < 3 months of age with sepsis have a yet undefined immunological predisposition; e.g. differences in lymphocyte subsets including regulatory T cells. Methods: We performed an exploratory, single center study between January 1st, 2019 and June 1st, 2021. Routine diagnostics included conventional culture (blood, cerebrospinal fluid, urine), PCR and inflammatory markers in infants < 90 days of age with suspected sepsis. We additionally analyzed lymphocyte subsets and CD4+ CD25+ forkhead box protein (FoxP3)+ Tregs at admission for sepsis workup as compared to age-matched controls. Results: A convenience sample cohort of n= 51 infants with sepsis workup was enrolled. Invasive bacterial infection (IBI) was diagnosed in 25 (49.0%) patients including two infants with a rhinovirus co-infection and viral infection in 14 (27.5%) neonates. No infectious cause was found in 12 cases. Infants with suspected LOS displayed a decreased abundance of CD4+ FoxP3+ T cells as compared to controls, which was most pronounced in the subgroup of infants with IBI. We also noticed elevated HLA-DR-positive CD3+ cells in infants with LOS and a higher CD4/CD8-ratio in infants with viral infection as compared to healthy controls. Infants with viral infections had a higher number of natural killer cells as compared to infants with IBI. Conclusion: Our exploratory data support the concept of a potential immaturity state and failed immune tolerance development for young infants with LOS. Future large-scale studies are needed to elucidate pre-sepsis conditions and to target the microbiome-immunity interplay as a potential risk pattern.

Increased Regulatory T Cells Precede the Development of Bronchopulmonary Dysplasia in Preterm Infants.

Regulatory T cells (Tregs) are important for the ontogenetic control of immune activation and tissue damage in preterm infants. However, the role of Tregs for the development of bronchopulmonary dysplasia (BPD) is yet unclear. The aim of our study was to characterize CD4+ CD25+ forkhead box protein 3 (FoxP3)+ Tregs in peripheral blood of well-phenotyped preterm infants (n = 382; 23 + 0 - 36 + 6 weeks of gestational age) with a focus on the first 28 days of life and the clinical endpoint BPD (supplemental oxygen for longer than 28 days of age). In a subgroup of preterm infants, we characterized the immunological phenotype of Tregs (n = 23). The suppressive function of Tregs on CD4+CD25- T cells was compared in preterm, term and adult blood. We observed that extreme prematurity was associated with increased Treg frequencies which peaked in the second week of life. Independent of gestational age, increased Treg frequencies were noted to precede the development of BPD. The phenotype of preterm infant Tregs largely differed from adult Tregs and displayed an overall naïve Treg population (CD45RA+/HLA-DR-/Helios+), especially in the first days of life. On day 7 of life, a more activated Treg phenotype pattern (CCR6+, HLA-DR+, and Ki-67+) was observed. Tregs of preterm neonates had a higher immunosuppressive capacity against CD4+CD25- T cells compared to the Treg compartment of term neonates and adults. In conclusion, our data suggest increased frequencies and functions of Tregs in preterm neonates which display a distinct phenotype with dynamic changes in the first weeks of life. Hence, the continued abundance of Tregs may contribute to sustained inflammation preceding the development of BPD. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.

Interventional radiotherapy (brachytherapy) achieves very good long-term quality of life in children and adolescents with soft-tissue sarcoma.

BACKGROUND: Effective local therapy (surgery, radiation) and systemic multidrug chemotherapy are mandatory for curing childhood sarcoma. The standard radiation therapy for pediatric patients with soft-tissue sarcoma (STS) is external beam radiotherapy (EBRT). Because EBRT may cause long-term side effects with adverse effects on the patients' health and quality of life (QoL), alternative strategies are required. Interventional radiotherapy (IRT; brachytherapy) is established as a standard treatment for several tumors in adulthood. Single-center series have reported low levels of late effects and improved QoL in survivors treated with IRT in childhood. However, IRT is still applied infrequently in pediatric patients. METHODS: Thirty patients with STS were treated with IRT between 1992 and 2012 at the University Hospital Schleswig Holstein, Germany. Five patients were lost to follow-up, and 25 patients (mean age at time of data collection 24.8 years [range, 10.7-36.1]) could be analyzed focusing on overall survival and QoL (EORTC-C30 questionnaire). For more detailed information regarding general and health-specific questions, a separate questionnaire was developed. RESULTS: Nineteen of 25 patients were alive 13.4 [1.6-25.2] years after first cancer disease, and the three-year overall survival was 76% (SE, 0.09). The score of QoL/global health status (76.2 [16.6-100]) in our patients outvalues the European (66.1) and equals the German (75.9) reference value. CONCLUSION: IRT is an effective treatment option for pediatric patients with localized STS. Its role among other radiation dose-sparing techniques such as proton beam therapy has to be defined in prospective studies.

FUT 2 polymorphism and outcome in very-low-birth-weight infants.

BACKGROUND: To determine whether the secretor gene fucosyltransferase (FUT)2 polymorphism G428A is predictive for adverse outcomes in a large cohort of very-low-birth weight (VLBW) infants. METHODS: We prospectively enrolled 2,406 VLBW infants from the population-based multicenter cohort of the German Neonatal network cohort (2009-2011). The secretor genotype (rs601338) was assessed from DNA samples extracted from buccal swabs. Primary study outcomes were clinical sepsis, blood-culture confirmed sepsis, intracerebral hemorrhage (ICH), necrotizing enterocolitis (NEC) or focal intestinal perforation requiring surgery, and death. RESULTS: Based on the assumption of a recessive genetic model, AA individuals had a higher incidence of ICH (AA: 19.0% vs. GG/AG: 14.9%, P = 0.04) which was not significant in the additive genetic model (multivariable logistic regression analysis; allele carriers: 365 cases, 1,685 controls; OR: 1.2; 95% CI: 0.99-1.4; P = 0.06). Other outcomes were not influenced by FUT2 genotype in either genetic model. CONCLUSION: This large-scale multicenter study did not confirm previously reported associations between FUT2 genotype and adverse outcomes in preterm infants.

Intrapartum colonization with Streptococcus pneumoniae, early-onset sepsis and deficient specific neonatal immune responses.

BACKGROUND: Intrapartum colonization with Streptococcus pneumoniae (S. pneumoniae) is a rare but important risk factor for severe courses of early-onset sepsis (EOS) in the newborn, as underlined in the case of a preterm infant born after 32 weeks of gestation described here. One potential explanation could be an immature immune response of the neonate to S. pneumoniae, however, immunological data in term and preterm infants are scarce. METHODS: To determine the neonatal immune responses to S. pneumoniae, flow-cytometry analysis of the cytokine production by CD14+ cells was performed after full pathogen stimulation with S. pneumoniae (serotype 18C, derived from an EOS case described here) of cord blood of 10 term (37-41 gestational weeks) and 6 preterm (31-32 gestational weeks) neonates, compared to peripheral venous blood samples of 10 healthy adults in vitro. RESULTS: Neonatal cytokine responses of term and preterm infants to S. pneumoniae are diminished compared to adults. The quantities of cytokine expression were comparable to immune responses induced by other important gram-positive pathogens of EOS such as Streptococcus agalacticae. CONCLUSION: Severe courses of EOS with S. pneumoniae may be attributed to remarkable deficiencies of the specific neonatal immune response. To protect the neonate from invasive pneumococcal disease, maternal immunization may be an important prevention strategy, as protective antibodies can be transferred through the placenta and vaccination of pregnant women may reduce colonization.

The modulatory effect of lipids and glucose on the neonatal immune response induced by Staphylococcus epidermidis.

BACKGROUND: Parenteral nutrition is an important risk factor for late onset sepsis in neonates. This may be caused by the long-term need of central venous access but also through a potentially modulating effect of lipids and glucose on the immune function. OBJECTIVE: It was the aim of this study to characterize the effect of lipids and glucose on the neonatal immune response in an in vitro Staphylococcus epidermidis sepsis model using whole cord blood of healthy term infants and preterm infants. RESULTS: At the single cell level, IL-6, IL-8 and TNF-α expression of CD14+ cells was significantly increased upon addition of 1% lipids, while the addition of clinically meaningful lipid concentrations had no remarkable effect. When glucose was added to whole cord blood cultures, a dose-dependent effect was demonstrated for IL-8 expression but not for other cytokines. CONCLUSIONS: These in vitro data suggest that the proinflammatory cytokine response to S. epidermidis may be modulated by lipids and glucose. Further studies are needed to investigate whether these findings are applicable to clinical settings and to evaluate the role of cytokine monitoring in infants receiving long-term parenteral nutrition.