Neonatal immune cells have heightened responses following in-utero exposure to chorioamnionitis or COVID-19

BACKGROUND

Chorioamnionitis alters neonatal immune responses. Gestational COVID-19 infection is associated with adverse pregnancy outcomes, but its impact on neonatal immunity is unclear. We hypothesized that gestational COVID-19 exposure would result in exaggerated neonatal immune responses, similar to chorioamnionitis-exposed neonates.

METHODS

Term umbilical cord blood mononuclear cells (CBMCs) were isolated from neonates exposed to chorioamnionitis, gestational COVID-19 or unexposed controls. CBMCs were cultured and stimulated with heat-killed Escherichia coli, Streptococcus agalactiae or Staphylococcus epidermidis. A multiplexed protein assay was used to measure cytokine levels in cell culture supernatants and flow cytometry was used to evaluate cellular-level cytokine expression.

RESULTS

Both chorioamnionitis-exposed and COVID-19 exposed CBMCs demonstrated upregulation of IL-1β and IL-6 compared to unexposed CBMCs, while only COVID-19 exposure resulted in IL-8 upregulation. There were no differences between chorioamnionitis-exposed and COVID-19 exposed CBMCs when these groups were directly compared. Flow cytometry demonstrated immune cell subset specific differences in cytokine expression between the exposure groups.

CONCLUSION

The fetal/neonatal response to maternal inflammation differed based on immune cell subset and etiology of inflammation, but the global neonatal cytokine responses were similar between exposure groups. This suggests that targeting perinatal inflammation rather than the specific etiology may be a possible therapeutic approach.

IMPACT

Neonatal immune cells have similar pathogen-associated global cytokine responses, but different cell-level immune responses, following in-utero exposure to chorioamnionitis or COVID-19. This is the first study to directly compare immune responses between neonates exposed to chorioamnionitis and COVID-19. This suggests that the fetal/neonatal cellular response to perinatal inflammation differs based on the etiology and severity of maternal inflammation, but still results in a similar overall inflammatory profile regardless of the cause of perinatal inflammation.

Response categorization and outcomes in extremely premature infants born at 22-26 weeks gestation that received inhaled nitric oxide for hypoxic respiratory failure

OBJECTIVE

To evaluate the outcomes of extremely premature infants who received inhaled nitric oxide(iNO) for hypoxic respiratory failure(HRF).

STUDY DESIGN

Retrospective analysis of 107 infants born 22-26 weeks gestation who received iNO for HRF at a single institution. Infants were categorized as positive, negative, or no responders based on change in FiO2 or OI. Underlying physiology was determined using Echocardiography/Radiography/Biochemistry.

RESULTS

63% of infants had a positive response; they received iNO earlier and were more likely to have acute pulmonary hypertension(PH). Positive response correlated with decreased incidence of death or grade 3 BPD at 36 weeks postmenstrual age, as compared to a negative response.

CONCLUSIONS

Extremely premature infants have a positive response rate to iNO comparable to term infants when used for PH in the transitional period. Infants with a negative response to iNO had worse outcomes, necessitating the determination of the underlying physiology of HRF prior to iNO initiation.

Hyperglycemia and Cytopenias as Signs of SARS-CoV-2 Delta Variant Infection in Preterm Infants

Information regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in premature infants remains limited. Early in the pandemic, several studies reported that the risk of infection in infants was relatively small and that affected infants had a milder disease than what was seen in adults. Since the increase of the delta variant (SARS-CoV-2 B.1.617.2) within the population, there have been increased reports of more severe disease in infants. We present 3 cases of premature, very low birth weight infants with confirmed SARS-CoV-2 infection who presented with significant hyperglycemia and bone marrow dysfunction. Two infants had presumed vertical transmission, and 1 infant was infected by respiratory transmission. Despite the mode of transmission, symptom onset and duration were similar in all infants. All resolved with symptomatic management. In the context of the continuing pandemic, evaluation for SARS-CoV-2 infection should be considered in premature very low birth weight infants who demonstrate certain patterns of acute metabolic and hematologic abnormalities.

Cardiorespiratory management of infants born at 22 weeks' gestation: The Iowa approach

The approach to clinical care of infants born at 22 weeks' gestation must be consistent and well-designed if optimal results are to be expected. Publications from several international centers have demonstrated that, although there may be variance in aspects of care in this vulnerable population, treatment should be neither random nor inconsistent. In designing a standardized approach, careful attention should be paid to the unique anatomy, physiology, and biochemistry of this vulnerable patient population. Emerging evidence, suggesting a link between cardiopulmonary health and longer-term sequela, highlights the importance of understanding the relationship between cardiorespiratory illnesses of the 22-week infant, treatments provided, and subsequent cardiopulmonary development. In this review we will provide an overview to our approach to cardiopulmonary assessment and treatment, with a particular emphasis on the importance of early recognition of atypical phenotypes, timely interventions with evidence-based treatments, and longitudinal monitoring.

Bifidobacterium longum Subspecies infantis Strain EVC001 Decreases Neonatal Murine Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a disease mainly of preterm infants with a 30-50% mortality rate and long-term morbidities for survivors. Treatment strategies are limited and have not improved in decades, prompting research into prevention strategies, particularly with probiotics. Recent work with the probiotic B. infantis EVC001 suggests that this organism may generate a more appropriate microbiome for preterm infants who generally have inappropriate gut colonization and inflammation, both risk factors for NEC. Experimental NEC involving Paneth cell disruption in combination with bacterial dysbiosis or formula feeding was induced in P14-16 C57Bl/6 mice with or without gavaged B. infantis. Following completion of the model, serum, small intestinal tissue, the cecum, and colon were harvested to examine inflammatory cytokines, injury, and the microbiome, respectively. EVC001 treatment significantly decreased NEC in a bacterial dysbiosis dependent model, but this decrease was model-dependent. In the NEC model dependent on formula feeding, no difference in injury was observed, but trending to significant differences was observed in serum cytokines. EVC001 also improved wound closure at six and twelve hours compared to the sham control in intestinal epithelial monolayers. These findings suggest that B. infantis EVC001 can prevent experimental NEC through anti-inflammatory and epithelial barrier restoration properties.

Routine Administration of a Multispecies Probiotic Containing Bifidobacterium and Lactobacillus to Very Low Birth Weight Infants Had No Significant Impact on the Incidence of Necrotizing Enterocolitis

Background: Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity in preterm infants, and prevention and treatment strategies have remained largely unchanged over the past several decades. As understanding of the microbiome has increased, probiotics have been hypothesized as a possible strategy for decreasing rates of NEC, and several studies have noted significant decreases in rates of NEC after initiation of probiotics in preterm infants. However, a recent AAP report cited caution on the use of probiotic use in part because studies of probiotic use in ELBW infants are lacking. As our unit began routine use of probiotics for all infants <33 weeks in 2015 and we are a leading institution for intact survival of ELBW infants, we attempted to answer if probiotic use can impact the rate of NEC in VLBW and ELBW infants. Methods: We conducted a single-center retrospective chart review of infants with modified Bell's stage ≥2a NEC for the 4 years prior to and 5 years after initiation of a protocol involving routine supplementation of a multispecies probiotic to premature infants at the University of Iowa, Stead Family Children's Hospital. The primary outcome measures were rates of modified Bell's stage ≥2a NEC and all-cause pre-discharge mortality at our institution before and after initiation of routine probiotic supplementation in 2015. Results: In our institution, neither the rates of modified Bell's stage ≥2a NEC, nor the rates of all-cause mortality were significantly altered in very low birth weight (VLBW) infants by the initiation of routine probiotic use (NEC rates pre-probiotic 2.1% vs. post-probiotic 1.5%; all-cause mortality rates pre-probiotic 8.4% vs. post-probiotic 7.4%). Characteristics of our two cohorts were overall similar except for a significantly lower 5-minute APGAR score in infants in the post-probiotic epoch (pre-probiotic 8 vs. post-probiotic 6 p = 0.0316), and significantly more infants in the post-probiotic epoch received probiotics (pre-probiotics 0% vs. post-probiotics 65%; p < 0.0001). Similarly, probiotic use had no impact on the incidence of NEC when we restricted our data to only extremely low birth weight (ELBW) infants (pre-probiotics 1.6% vs post-probiotics 4.1%). When we restricted our analysis to only inborn infants, probiotics still had no impact on NEC rates in VLBW infants (1.5% pre- and 1.1% post-probiotic, p = 0.61) or ELBW infants (2% pre- and 2.1% post-probiotic, p = 0.99) Conclusions: Contrary to other studies, we found no significant difference in rates of modified Bell's stage ≥2a NEC or all-cause pre-discharge mortality in VLBW infants following routine administration of a multispecies probiotic supplement.