Carlo Pietrasanta

Chorioamnionitis and neonatal outcome in preterm infants: a clinical overview.

Abstract The term chorioamnionitis is used to refer to an intrauterine infection/inflammation occurring between the maternal tissues and the fetal membranes (choriodecidual space) or in the fetal annexes (chorioamniotic membranes, amniotic fluid, umbilical cord). Histological examination of the placenta is the gold standard for diagnosis. However, clinical, biochemical and microbiological criteria are also used to define the disease. The literature contains a large body of evidence showing that chorioamnionitis is the leading cause of very preterm birth and, therefore, contributes significantly to neonatal morbidity and mortality. In recent decades, numerous studies have attempted to establish whether, and to what extent, intrauterine infection/inflammation might negatively affect the short- and long-term outcome of preterm infants. The question is still unanswered. The discrepancy observed across studies can be attributed largely to the use of different inclusion and exclusion criteria, diagnostic criteria and methods, and to whether or not potential confounding factors, such as gestational age were considered. Anyhow, the association between chorioamnionitis and severe prematurity requires serious efforts by researchers to clarify the mechanisms linking intrauterine infection/inflammation with preterm birth, and thus to identify strategies that may guide clinicians’ diagnostic and therapeutic choices, with regard to both mothers and infants.

Toll-like receptor 8 agonist nanoparticles mimic immunomodulating effects of the live BCG vaccine and enhance neonatal innate and adaptive immune responses

Background Newborns display distinct immune responses, leaving them vulnerable to infections and impairing immunization. Targeting newborn dendritic cells (DCs), which integrate vaccine signals into adaptive immune responses, might enable development of age‐specific vaccine formulations to overcome suboptimal immunization. Objective Small‐molecule imidazoquinoline Toll‐like receptor (TLR) 8 agonists robustly activate newborn DCs but can result in reactogenicity when delivered in soluble form. We used rational engineering and age‐ and species‐specific modeling to construct and characterize polymer nanocarriers encapsulating a TLR8 agonist, allowing direct intracellular release after selective uptake by DCs. Methods Chemically similar but morphologically distinct nanocarriers comprised of amphiphilic block copolymers were engineered for targeted uptake by murine DCs in vivo, and a range of TLR8 agonist–encapsulating polymersome formulations were then synthesized. Novel 96‐well in vitro assays using neonatal human monocyte‐derived DCs and humanized TLR8 mouse bone marrow–derived DCs enabled benchmarking of the TLR8 agonist–encapsulating polymersome formulations against conventional adjuvants and licensed vaccines, including live attenuated BCG vaccine. Immunogenicity of the TLR8 agonist adjuvanted antigen 85B (Ag85B)/peptide 25–loaded BCG‐mimicking nanoparticle formulation was evaluated in vivo by using humanized TLR8 neonatal mice. Results Although alum‐adjuvanted vaccines induced modest costimulatory molecule expression, limited TH‐polarizing cytokine production, and significant cell death, BCG induced a robust adult‐like maturation profile of neonatal DCs. Remarkably, TLR8 agonist polymersomes induced not only newborn DC maturation profiles similar to those induced by BCG but also stronger IL‐12p70 production. On subcutaneous injection to neonatal mice, the TLR8 agonist–adjuvanted Ag85B peptide 25 formulation was comparable with BCG in inducing Ag85B‐specific CD4+ T‐cell numbers. Conclusion TLR8 agonist–encapsulating polymersomes hold substantial potential for early‐life immunization against intracellular pathogens. Overall, our study represents a novel approach for rational design of early‐life vaccines. Graphical abstract Figure. No Caption available.

Vaccine administration in children with chronic kidney disease.

Pediatric patients with severe chronic kidney disease (CKD) on conservative treatment, on dialysis, and those with renal transplantation are at a higher risk for infectious diseases as the result of impaired immune responses against infectious agents. Infections in these patients can have drastic consequences for disease morbidity and mortality. Immunization is a crucial preventive strategy for disease management in this pediatric population. However, vaccination coverage among children with CKD remains low due to safety concerns and doubts about vaccine immunogenicity and efficacy. In this study, we reviewed why children with CKD are at higher risk of infections, the importance of vaccinations among these children, barriers to vaccinations, and recommend the best vaccination schedules. Overall, vaccines have acceptable immunogenicity, efficacy, and safety profiles in children with CKD. However, in some cases, the protective antibody levels induced by vaccines and the benefits and risks of booster vaccine doses must be individually managed. Furthermore, close contacts and household members of these children should complete age-appropriate vaccination schedules to increase the childs indirect protection.

Predictive factors for neonatal survival in women with periviable preterm rupture of the membranes

Abstract Objective: To identify clinical, hematological or instrumental factors available at the time of the diagnosis that may predict neonatal survival in periviable preterm premature rupture of the membranes (PROM). Methods: We report on a cohort (n = 85) of women with periviable PROM (14–23.6 weeks’ gestation) occurring over a 10-year period in a single institution. The main outcome chosen was the survival rate beyond the neonatal period. Variables considered were those available at 24 h after admission. Results: The overall survival rate was 49%. In the multivariate analysis, significant contributions for the prediction of neonatal survival were provided by four variables: genetic amniocentesis-related cause of PROM (p < 0.001), gestational age at PROM (p = 0.019), CRP > 1 mg/dl within 24 h after admission (p = 0.042) and oligohydramnios (largest vertical pocket ≤2 cm) (p = 0.041). The corresponding adjusted odds ratio (OR)s were 73.9 (95% CI: 7.9–694.7), 1.5 (95% CI: 1.1–2.0) per week, 0.26 (95% CI: 0.07–0.95) and 0.20 (95% CI: 0.04–0.93), respectively. Conclusions: Genetic amniocentesis-related cause of PROM, gestational age at PROM, C-reactive protein >1 mg/dl and oligohydramnios are significantly associated with survival in women with periviable PROM. The evaluation of these few and easily available variables may help physicians and patients in the decision-making process of this demanding condition.

Presepsin (Soluble CD14 Subtype): Reference Ranges of a New Sepsis Marker in Term and Preterm Neonates

Objective Presepsin (soluble CD14 subtype) has been shown to be beneficial as a sepsis marker in adults. Nevertheless, very few data are available in neonates. The aim of the present study was to determine reference ranges of presepsin in term and preterm neonates. Methods Healthy term neonates and preterm neonates without clinical signs of infection admitted to the Neonatal Unit were consecutively enrolled. Presepsin concentrations in whole blood were measured using a point-of-care assay system located in the Unit. Demographic data, antenatal and perinatal variables commonly affecting C-reactive protein and procalcitonin values were considered. Results Of the 684 neonates enrolled in the study, 484 (70.8%) were born at term and 200 (29.2%) were preterm (24–36 weeks’ gestation). In term infants, presepsin median value was 603.5 pg/mL (interquartile range: 466.5–791 pg/mL; 5th and 95th centiles: 315 and 1178 pg/mL respectively). In preterm infants, presepsin median value was slightly higher, equal to 620 pg/mL (interquartile range: 503–864 pg/mL; 5th and 95th centiles: 352 and 1370 pg/mL respectively). The reference ranges of presepsin we determined were much higher than those seen in healthy adults. No correlation between presepsin levels and postnatal age was observed, as well as no significant difference was demonstrated in preterm neonates at different gestational ages. None of the variables analyzed affected presepsin levels at a clinical significant extent. Conclusion For the first time, this study provides reference ranges of presepsin in term and preterm neonates. Having reliable reference values is crucial for obtaining an adequate diagnostic accuracy. Based on our results, most variables commonly affecting C-reactive protein and procalcitonin values do not affect presepsin levels, which suggests that presepsin could be an effective sepsis marker. Further investigations in large groups of neonates with sepsis are needed to determine the diagnostic and prognostic value of this biomarker.

A Meningococcal Outer Membrane Vesicle Vaccine Incorporating Genetically Attenuated Endotoxin Dissociates Inflammation from Immunogenicity

Background Group B Neisseria meningitidis, an endotoxin-producing Gram-negative bacterium, causes the highest incidence of group B meningococcus (MenB) disease in the first year of life. The Bexsero vaccine is indicated in Europe from 8 weeks of age. Endotoxin components of outer membrane vesicles (OMVs) or soluble lipopolysaccharide (LPS) represent a potential source of inflammation and residual reactogenicity. The purpose of this study was to compare novel candidate MenB vaccine formulations with licensed vaccines, including Bexsero, using age-specific human in vitro culture systems. Methods OMVs from wild type- and inactivated lpxL1 gene mutant-N. meningitidis strains were characterized in human neonatal and adult in vitro whole blood assays and dendritic cell (DC) arrays. OMVs were benchmarked against licensed vaccines, including Bexsero and whole cell pertussis formulations, with respect to Th-polarizing cytokine and prostaglandin E2 production, as well as cell surface activation markers (HLA-DR, CD86, and CCR7). OMV immunogenicity was assessed in mice. Results ΔlpxLI native OMVs (nOMVs) demonstrated significantly less cytokine induction in human blood and DCs than Bexsero and most of the other pediatric vaccines (e.g., PedvaxHib, EasyFive, and bacillus Calmette–Guérin) tested. Despite a much lower inflammatory profile in vitro than Bexsero, ΔlpxLI nOMVs still had moderate DC maturing ability and induced robust anti-N. meningitidis antibody responses after murine immunization. Conclusion A meningococcal vaccine comprised of attenuated LPS-based OMVs with a limited inflammatory profile in vitro induces robust antigen-specific immunogenicity in vivo.

Adjuvant Effect of Bacille Calmette–Guérin on Hepatitis B Vaccine Immunogenicity in the Preterm and Term Newborn

Immunization is key to protecting term and preterm infants from a heightened risk of infection. However, preterm immunity is distinct from that of the term, limiting its ability to effectively respond to vaccines routinely given at birth, such as hepatitis B vaccine (HBV). As part of the Expanded Program on Immunization, HBV is often given together with the live-attenuated vaccine Bacille Calmette–Guérin (BCG), known to activate multiple pattern-recognition receptors. Of note, some clinical studies suggest BCG can enhance efficacy of other vaccines in term newborns. However, little is known about whether BCG can shape Th-polarizing cytokine responses to HBV nor the age-dependency of such effects, including whether they may extend to the preterm. To characterize the effects of BCG on HBV immunogenicity, we studied individual and combined administration of these vaccines to cord newborn and adult human whole blood and mononuclear cells in vitro and to neonatal and adult mice in vivo. Compared to either BCG or HBV alone, (BCG + HBV) synergistically enhanced in vitro whole blood production of IL-1β, while (BCG + HBV) also promoted production of several cytokines/chemokines in all age groups, age-specific enhancement included IL-12p70 in the preterm and GM-CSF in the preterm and term. In human mononuclear cells, (BCG + HBV) enhanced mRNA expression of several genes including CSF2, which contributed to clustering of genes by vaccine treatment via principle component analysis. To assess the impact of BCG on HBV immunization, mice of three different age groups were immunized subcutaneously with, BCG, HBV, (BCG + HBV) into the same site; or BCG and HBV injected into separate sites. Whether injected into a separate site or at the same site, co-administration of BCG with HBV significantly enhanced anti-HBV IgG titers in mice immunized on day of life-0 or -7, respectively, but not in adult mice. In summary, our data demonstrate that innate and adaptive vaccine responses of preterm and term newborns are immunologically distinct. Furthermore, BCG or “BCG-like” adjuvants should be further studied as a promising adjuvantation approach to enhance immunogenicity of vaccines to protect these vulnerable populations.

Urinary metabolomic analysis to identify preterm neonates exposed to histological chorioamnionitis: A pilot study

Objective Chorioamnionitis is a leading cause of preterm birth worldwide, with higher incidence at lower gestational ages. An early and reliable diagnosis of histological chorioamnionitis (HCA) in preterm infants may be helpful in guiding postnatal management, especially the administration of prophylactic antibiotics to prevent early-onset sepsis. The main aim of this study was to investigate metabolomic analysis of urines collected in the first 24 hours of life as diagnostic tool of HCA. Methods Gestational age-, birth weight-, delivery mode- and sex- matched (1:2) preterm neonates (< 35 weeks’ gestation) born to mothers with or without HCA were enrolled from an observational study. Gas chromatography-mass spectrometry (GC-MS)-based metabolomic analysis was performed on urine samples non-invasively collected in the first 24 hours of life. Univariate analysis, partial least square discriminant analysis (PLS-DA) and its associated variable importance in projection (VIP) score were performed. The most affected metabolic pathways were examined by Metabolite Sets Enrichment Analysis (MSEA). Results Fifteen cases (mean GA 30.2 ± 3.8 weeks, mean BW 1415 ± 471.9 grams) and 30 controls (mean GA 30.2 ± 2.9 weeks, mean BW 1426 ± 569.8 grams) were enrolled. Following univariate analysis, 29 metabolites had a significantly different concentration between cases and controls. The supervised PLS-DA model confirmed a separation between the two groups. Only gluconic acid, an oxidation product of glucose, was higher in cases than in controls. All other VIP metabolites were more abundant in the control group. Glutamate metabolism, mitochondrial electron transport chain, citric acid cycle, galactose metabolism, and fructose and mannose degradation metabolism were the most significantly altered pathways (P < 0.01). Conclusions For the first time, urinary metabolomics was able to discriminate neonates born to mothers with and without HCA. The identification of specifically altered metabolic pathways may be helpful in understanding metabolic derangement following chorioamnionitis.

Identification and characterization of stimulator of interferon genes as a robust adjuvant target for early life immunization

Immunization is key to preventing infectious diseases, a leading cause of death early in life. However, due to age-specific immunity, vaccines often demonstrate reduced efficacy in newborns and young infants as compared to adults. Here, we combined in vitro and in vivo approaches to identify adjuvant candidates for early life immunization. We employed newborn and adult bone marrow-derived dendritic cells (BMDCs) to perform a screening of pattern recognition receptor agonists and found that the stimulator of interferon genes ligand 2′3′-cGAMP (hereafter cGAMP) induces a comparable expression of surface maturation markers in newborn and adult BMDCs. Then, we utilized the trivalent recombinant hemagglutinin (rHA) influenza vaccine, Flublok, as a model antigen to investigate the role of cGAMP in adult and early life immunization. cGAMP adjuvantation alone could increase rHA-specific antibody titers in adult but not newborn mice. Remarkably, as compared to alum or cGAMP alone, immunization with cGAMP formulated with alum (Alhydrogel) enhanced newborn rHA-specific IgG2a/c titers ~400-fold, an antibody subclass associated with the development of IFNγ-driven type 1 immunity in vivo and endowed with higher effector functions, by 42 days of life. Highlighting the amenability for successful vaccine formulation and delivery, we next confirmed that cGAMP adsorbs onto alum in vitro. Accordingly, immunization early in life with (cGAMP+alum) promoted IFNγ production by CD4+ T cells and increased the proportions and absolute numbers of CD4+ CXCR5+ PD-1+ T follicular helper and germinal center (GC) GL-7+ CD138+ B cells, suggesting an enhancement of the GC reaction. Adjuvantation effects were apparently specific for IgG2a/c isotype switching without effect on antibody affinity maturation, as there was no effect on rHA-specific IgG avidity. Overall, our studies suggest that cGAMP when formulated with alum may represent an effective adjuvantation system to foster humoral and cellular aspects of type 1 immunity for early life immunization.

Iatrogenic Anetoderma of Prematurity: A Case Report and Review of the Literature

Anetoderma is a skin disorder characterized by focal loss of elastic tissue in the mid dermis, resulting in localized areas of macular depressions or pouchlike herniations of skin. An iatrogenic form of anetoderma has been rarely described in extremely premature infants and has been related to the placement of monitoring devices on the patient skin. Because of the increasing survival of extremely premature infants, it is easy to foresee that the prevalence of anetoderma of prematurity will increase in the next future. Although it is a benign lesion, it persists over time and can lead to significant aesthetic damage with need for surgical correction. Sometimes the diagnosis can be difficult, especially when the atrophic lesions become evident after discharge. Here, we report on a premature infant born at 24 weeks of gestation, who developed multiple anetodermic patches of skin on the trunk at the sites where electrocardiographic electrodes were previously applied. The knowledge of the disease can encourage a more careful management of the skin of extremely premature babies and aid the physicians to diagnose the disease when anetoderma patches are first encountered later in childhood.