Role of polymorphic variants as genetic modulators of infection in neonatal sepsis

A meta-analysis of the association between inflammatory cytokine polymorphism and neonatal sepsis

OBJECTIVE

The purpose of this study is to investigate the relationship between single nucleotide polymorphisms of inflammatory cytokines and neonatal sepsis through meta-analysis.

METHODS

We collected research literature on the correlation between inflammatory cytokine polymorphisms and neonatal sepsis published before August 2023 through computer searches of databases such as PubMed, Embase, etc. The Stata 14.0 software was utilized for Meta-analysis. To assess heterogeneity, the chi-squared Q-test and I2 statistics were used. The Egger and Begg tests were conducted to determine the possibility of publication bias.

RESULTS

After reviewing 1129 articles, 29 relevant articles involving 3348 cases and 5183 controls were included in the study. The meta-analysis conducted on IL-1βrs1143643 polymorphism revealed significant findings: the T allele genotype has a lower risk of neonatal sepsis(P = 0.000, OR = 0.224, 95% CI: 0.168-0.299), while the TC and TT genotypes showed an increased risk(TC: P = 0.000,OR = 4.251, 95% CI: 2.226-8.119; TT: P = 0.019,OR = 2.020, 95% CI: 1.122-3.639). Similarly, newborns with the IL-6-174 CC genotype had a significantly higher risk of sepsis(P = 0.000,OR = 1.591, 95% CI: 1.154-2.194), while those with the IL-8-rs4073 TT (P = 0.003,OR = 0.467, 95% CI: 0.280-0.777)and TT + AA(P = 0.003,OR = 0.497, 95% CI: 0.315-0.785) genotypes had a significantly lower risk of sepsis. For the IL-10-1082 gene, newborns with the AA genotype(P = 0.002,OR = 1.702, 95% CI: 1.218-2.377), as well as those with the AA + GA genotype(P = 0.016,OR = 1.731, 95% CI: 1.108-2.705), had a significantly higher risk of sepsis. Lastly, newborns carrying the TNF-α-308 A allele (P = 0.016,OR = 1.257, 95% CI: 1.044-1.513)or the AA genotype(P = 0.009,OR = 1.913, 95% CI: 1.179-3.10) have a significantly increased risk of sepsis. Notwithstanding, additional studies must be included for validation. Applying these cytokines in clinical practice and integrating them into auxiliary examinations facilitates the early detection of susceptible populations for neonatal sepsis, thereby providing a new diagnostic and therapeutic approach for neonatal sepsis.

The monocyte-derived cytokine response in whole blood from preterm newborns against sepsis-related bacteria is similar to term newborns and adults

Introduction

Sepsis is characterized by a dysregulated innate immune response. It is a leading cause of morbidity and mortality in newborns, in particular for newborns that are born premature. Although previous literature indicate that the pro-inflammatory response may be impaired in preterm newborns, serum levels of monocyte-derived cytokines, such as TNF-α and IL-6, vary highly between newborns and can reach adult-like concentrations during sepsis. These contradictory observations and the severe consequences of neonatal sepsis in preterm newborns highlight the need for a better understanding of the pro-inflammatory cytokine response of preterm newborns to improve sepsis-related outcomes.

Methods and results

Using an in vitro model with multiple read outs at the transcriptional and protein level, we consistently showed that the monocyte-derived cytokine response induced by sepsis-related bacteria is comparable between preterm newborns, term newborns and adults. We substantiated these findings by employing recombinant Toll-like receptor (TLR) ligands and showed that the activation of specific immune pathways, including the expression of TLRs, is also similar between preterm newborns, term newborns and adults. Importantly, we showed that at birth the production of TNF-α and IL-6 is highly variable between individuals and independent of gestational age.

Discussion

These findings indicate that preterm newborns are equally capable of mounting a pro-inflammatory response against a broad range of bacterial pathogens that is comparable to term newborns and adults. Our results provide a better understanding of the pro-inflammatory response by preterm newborns and could guide the development of interventions that specifically modulate the pro-inflammatory response during sepsis in preterm newborns.

Genetic polymorphisms associated with sepsis incidence, severity, and outcomes among neonates: A mini-review

Genetic variation remains a topic of great interest due to its potential as a risk factor for various diseases. Interactions between genes contribute to diverse phenotypes in response to factors such as infection. The impact of genetic background on susceptibility and clinical outcomes, particularly in neonatal sepsis, has gained recognition. The variability in sepsis susceptibility and outcomes can be attributed to the genetic diversity in coding regions and regulatory elements of genes related to innate immune response. Recent advances in genomics and technology have shed light on genetic polymorphisms among humans, often represented by single-nucleotide polymorphisms (SNPs). These SNPs encode proteins crucial for recognizing and responding to pathogenic bacteria, including Toll-like receptor 4, CD14, tumor necrosis factor-alpha, as well as interleukin-1-10. This literature review specifically discusses the involvement of genetic polymorphism during the pathogenesis stage of sepsis, with an emphasis on previous research findings in neonatal sepsis cases, aiming to discuss the implications of polymorphism in sepsis susceptibility and outcomes.

Identification of an Immune-Related Gene Diagnostic Model and Potential Drugs in Sepsis Using Bioinformatics and Pharmacogenomics Approaches

Purpose

Sepsis is an organ dysfunction with high mortality. Early identification, diagnosis, and effective treatment of sepsis are beneficial to the survival of patients. This study aimed to find potential diagnosis and immune-related genes, and drug targets, which could provide novel diagnostic and therapeutic markers for sepsis.

Patients and Methods

The GSE69063, GSE154918 and GSE28750 datasets were integrated to evaluate immune infiltration and identify differentially expressed genes (DEGs) and immune-related genes. Weighted gene co-expression network analysis (WGCNA) was applied to find the hub module related to immune score and sepsis. Immune-related key genes were screened out by taking interaction of DEGs, immune-related genes, and genes in hub module. Protein-protein interaction (PPI) analysis was used to further screen immune-related hub genes, followed by construction of a diagnostic model based on immune-related hub genes. Functional analysis and drug prediction of immune-related hub genes were, respectively, performed by David software and DGIdb database, followed by expression validation by reverse transcriptase polymerase chain reaction (RT-PCR).

Results

Totally, 93 immune-related key genes were identified between 561 DEGs, 1793 immune-related genes and 12,459 genes in the hub module of WGCNA. Through PPI analysis, a total of 5 diagnose and immune-related hub genes were further obtained, including IL7R, IL10, CD40LG, CD28 and LCN2. Relationship pairs between these 5 genes and immune cell were identified, including LCN2/IL7R/CD28-activated dendritic cell and IL10-immature B cell. Based on pharmacogenomics, 17 candidate drugs might interact with IL 10, including CYCLOSPORINE. Six candidate drugs might interact with CD28 and 11 with CD40LG, CD40LG and CD28 were drug targets of ALDESLEUKIN. Four significantly enriched signaling pathways were identified, such as T cell receptor signaling pathway, NF-kappa B signaling pathway and JAK-STAT signaling pathway.

Conclusion

The 5-gene diagnostic model could be used to diagnose and guide clinical immunotherapy for sepsis.

Association between innate immunity gene polymorphisms and neonatal sepsis development: a systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis was to analyze all available data from studies investigating associations between polymorphisms in genes responsible for innate immunity and neonatal sepsis development.

METHODS

A comprehensive literature search, reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-S guidelines, was performed with no language restriction. Studies derived using the PICO (population, intervention, comparison and outcomes) strategy, with data on the genotype distribution for innate immunity gene polymorphisms in newborns with and without sepsis. Data were analyzed using Review Manager. The Cochran-Mantel-Haenszel test was used to calculate odds ratios with 95% confidence intervals. Heterogeneity was tested using the I² index.

RESULTS

From a total of 9428 possibly relevant articles, 33 qualified for inclusion in this systematic review. According to the STrengthening the REporting of Genetic Association Studies, 23 studies were found to be of moderate quality, while 10 were of low quality. The results showed an association of the mannose-binding lectin (MBL) exon 1 genetic polymorphism with the risk of culture-proven sepsis. Toll-like receptor (TLR) 4 rs4986791 genotype distribution suggests its association with the increased risk of culture-proven sepsis. The certainty of evidence per GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) varied from very low to low. Publication bias was not detected.

CONCLUSIONS

Out of the 11 investigated single-nucleotide polymorphisms, this meta-analysis found a possible association between the risk for culture-proven sepsis and MBL exon 1 and TLR4 rs4986791 polymorphisms. There is an evident need for larger well-designed, multicentric observational studies investigating inflammatory gene polymorphisms in neonatal sepsis.

Effect of TLR-4 gene polymorphisms on sepsis susceptibility in neonates: a systematic review and meta-analysis

Aim: To clarify the role of polymorphisms rs4986790 and rs4986791 in TLR-4 with susceptibility to neonatal sepsis. Methods: To evaluate the possible correlation of polymorphisms rs4986790 and rs4986791 with sepsis risk, odds ratios (ORs) were calculated. The heterogeneity was evaluated by χ²-based Q-test. Results: For rs4986790, ORs were 1.36 (95% CI: 1.05-1.79, p = 0.017) and 1.84 (95% CI: 0.04-7.9, p = 0.410) under AG+GG versus AA and G vs. A models, respectively. For rs4986791, ORs were 2.22 (95% CI: 1.25-3.94, p = 0.006) and 2.20 (95% CI: 1.26-3.85, p = 0.005) under CT+TT versus CC and of T versus C models, respectively. Conclusion: The rs4986790 and rs4986791 polymorphisms in TLR-4 could influence the sepsis susceptibility in neonates.

Relationship of Bactericidal Permeability Increasing Protein (BPI) Polymorphysm rs1341023, rs5743507, Tumor Necrosis Factor Alpha (TNF-α) rs361525, rs1800629 with Neonatal Sepsis

Background: Neonatal sepsis is a problem in the field of child health because the incidence is increasing every year and often ends in death. This study aimed to investigate the relationship between TNF-α and BPI gene polymorphisms with neonatal sepsis. Methods: PCR and sequencing examinations were performed on 60 DNA samples consisting of 30 samples of neonatal sepsis and 30 samples of non-neoptic sepsis. Furthermore, data in the form of DNA mutation tables were statistically processed by univariate, bivariate, and multivariate analysis. It is considered meaningful if p<0.05. Result: The results showed that BPI rs1341023, rs5743507 and TNF-α rs361525, rs1800629 only BPI rs1341023 and TNF-α rs1800629 were mutated. Of the two genes, only TNF-α rs1800629 had a significant association with neonatal sepsis (p<0.05). Conclusion: This study proved that the TNF-α rs1800629 mutation was the most important polymorphism in the occurrence of neonatal sepsis (p<0.05). Keywords: BPI, TNF-α, Neonatal, Polymorphism, Sepsis

Vital signs as physiomarkers of neonatal sepsis

Neonatal sepsis accounts for significant morbidity and mortality, particularly among premature infants in the Neonatal Intensive Care Unit. Abnormal vital sign patterns serve as physiomarkers of sepsis and provide early warning of illness before overt clinical decompensation. The systemic inflammatory response to pathogens signals the autonomic nervous system, leading to changes in temperature, respiratory rate, heart rate, and blood pressure. In infants with comorbidities of prematurity, vital sign abnormalities often occur in the absence of infection, which confounds sepsis diagnosis. This review will cover the mechanisms of vital sign changes in neonatal sepsis, including the cholinergic anti-inflammatory pathway mediated by the vagus nerve, which is critical to the host response to infectious and inflammatory insults. We will also review the clinical implications of vital sign changes in neonatal sepsis, including their use in early warning scores and systems to direct clinicians to the bedside of infants with physiologic changes that might be due to sepsis. IMPACT: This manuscript summarizes and reviews the relevant literature on the physiological manifestations of neonatal sepsis and how we monitor and analyze these through vital signs and advanced analytics.

Sex- and Gender-Dependent Differences in Clinical and Preclinical Sepsis

ABSTRACT

In this mini-review we provide an overview of sex- and gender-dependent issues in both clinical and preclinical sepsis. The increasing recognition for the need to account for sex and gender in biomedical research brings a unique set of challenges and requires researchers to adopt best practices when conducting and communicating sex- and gender-based research. This may be of particular importance in sepsis, given the potential contribution of sex bias in the failures of translational sepsis research in adults and neonates. Clinical evidence of sex-dependent differences in sepsis is equivocal. Since clinical studies are limited to observational data and confounded by a multitude of factors, preclinical studies provide a unique opportunity to investigate sex differences in a controlled, experimental environment. Numerous preclinical studies have suggested that females may experience favorable outcomes in comparison with males. The underlying mechanistic evidence for sex-dependent differences in sepsis and other models of shock (e.g., trauma-hemorrhage) largely centers around the beneficial effects of estrogen. Other mechanisms such as the immunosuppressive role of testosterone and X-linked mosaicism are also thought to contribute to observed sex- and gender-dependent differences in sepsis. Significant knowledge gaps still exist in this field. Future investigations can address these gaps through careful consideration of sex and gender in clinical studies, and the use of clinically accurate preclinical models that reflect sex differences. A better understanding of sex-and gender-dependent differences may serve to increase translational research success.

Chorioamnionitis and Risk for Maternal and Neonatal Sepsis: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the risk of maternal and neonatal sepsis associated with chorioamnionitis.

DATA SOURCES

PubMed, BIOSIS, and ClinicalTrials.gov databases were systematically searched for full-text articles in English from inception until May 11, 2020.

METHODS OF STUDY SELECTION

We screened 1,251 studies. Randomized controlled trials, case-control, or cohort studies quantifying a relationship between chorioamnionitis and sepsis in mothers (postpartum) or neonates born at greater than 22 weeks of gestation were eligible. Studies were grouped for meta-analyses according to exposures of histologic or clinical chorioamnionitis and outcomes of maternal or neonatal sepsis.

TABULATION, INTEGRATION, AND RESULTS

One hundred three studies were included, and 55 met criteria for meta-analysis (39 studies of preterm neonates, 10 studies of general populations of preterm and term neonates, and six studies of late preterm and term neonates). Study details and quantitative data were abstracted. Random-effects models were used to generate pooled odds ratios (ORs); most studies only reported unadjusted results. Histologic chorioamnionitis was associated with confirmed and any early-onset neonatal sepsis (unadjusted pooled ORs 4.42 [95% CI 2.68-7.29] and 5.88 [95% CI 3.68-9.41], respectively). Clinical chorioamnionitis was also associated with confirmed and any early-onset neonatal sepsis (unadjusted pooled ORs 6.82 [95% CI 4.93-9.45] and 3.90 [95% CI 2.74-5.55], respectively). Additionally, histologic and clinical chorioamnionitis were each associated with higher odds of late-onset sepsis in preterm neonates. Confirmed sepsis incidence was 7% (early-onset) and 22% (late-onset) for histologic and 6% (early-onset) and 26% (late-onset) for clinical chorioamnionitis-exposed neonates. Three studies evaluated chorioamnionitis and maternal sepsis and were inconclusive.

CONCLUSION

Both histologic and clinical chorioamnionitis were associated with early- and late-onset sepsis in neonates. Overall, our findings support current guidelines for preventative neonatal care. There was insufficient evidence to determine the association between chorioamnionitis and maternal sepsis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42020156812.

Germline Genetic Variants of Viral Entry and Innate Immunity May Influence Susceptibility to SARS-CoV-2 Infection: Toward a Polygenic Risk Score for Risk Stratification

The ongoing COVID-19 pandemic caused by the novel coronavirus, SARS-CoV-2 has affected all aspects of human society with a special focus on healthcare. Although older patients with preexisting chronic illnesses are more prone to develop severe complications, younger, healthy individuals might also exhibit serious manifestations. Previous studies directed to detect genetic susceptibility factors for earlier epidemics have provided evidence of certain protective variations. Following SARS-CoV-2 exposure, viral entry into cells followed by recognition and response by the innate immunity are key determinants of COVID-19 development. In the present review our aim was to conduct a thorough review of the literature on the role of single nucleotide polymorphisms (SNPs) as key agents affecting the viral entry of SARS-CoV-2 and innate immunity. Several SNPs within the scope of our approach were found to alter susceptibility to various bacterial and viral infections. Additionally, a multitude of studies confirmed genetic associations between the analyzed genes and autoimmune diseases, underlining the versatile immune consequences of these variants. Based on confirmed associations it is highly plausible that the SNPs affecting viral entry and innate immunity might confer altered susceptibility to SARS-CoV-2 infection and its complex clinical consequences. Anticipating several COVID-19 genomic susceptibility loci based on the ongoing genome wide association studies, our review also proposes that a well-established polygenic risk score would be able to clinically leverage the acquired knowledge.

Role of Toll-Like Receptors 2 and 4 Genes Polymorphisms in Neonatal Sepsis in a Developing Country: A Pilot Study

Objective Toll-like receptors (TLR) are one of the key molecules that alert the immune system to the presence of microbial infections. This study attempts to elucidate the role of TLR2 and TLR4 polymorphisms in neonatal sepsis.

Methods A case–control study including 30 neonates with confirmed sepsis compared with 20 neonates in a control group. TLR2 and TLR24 gene polymorphisms were confirmed by polymerase chain reaction.

Results The majority of infections were attributed to gram-negative organisms (72.5%) namely Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Results also revealed that incidence of TLR polymorphism was significantly different between the sepsis and control groups (p = 0.016). The most common polymorphism was TLR2; Arg 753 Gln (16.7%). Presence of TLR polymorphism was also associated with a longer duration of therapy (a median of 10 days for cases with positive polymorphism compared with 6.5 days for negative cases; p = 0.001).

Conclusion This pilot study suggests that any polymorphisms in TLR2 and TLR4 might have a role that interferes with the innate immune response of newborn.

Group B streptococcal disease in the mother and newborn-A review

Group B Streptococcus, a common commensal in the gut of humans and in the lower genital tract in women, remains an important cause of neonatal mortality and morbidity. The incidence of early onset disease has fallen markedly in countries that test women for carriage at 35-37 weeks of pregnancy and then offer intrapartum prophylaxis with penicillin during labour. Countries that do not test, but instead employ a risk factor approach, have not seen a similar fall. There are concerns about the effect on the neonatal microbiome of widespread use of antibiotic prophylaxis during labour, but so far the effects seem minor and temporary. Vaccination against GBS would be acceptable to most women and GBS vaccines are in the early stages of development. Tweetable abstract: Group B Strep is a key cause of infection, death and disability in young babies. Antibiotics given in labour remain the mainstay of prevention, until a vaccine is available.

Association of Histological and Clinical Chorioamnionitis With Neonatal Sepsis Among Preterm Infants: A Systematic Review, Meta-Analysis, and Meta-Regression

Chorioamnionitis (CA) is considered a key risk factor for very preterm birth and for developing early onset sepsis (EOS) in preterm infants, but recent data suggest that CA might be protective against late onset sepsis (LOS). We performed a systematic review and meta-analysis of studies exploring the association between CA and sepsis. A comprehensive literature search was performed in PubMed/MEDLINE and EMBASE, from their inception to December 1, 2018. A random-effects model was used to calculate odds ratios (OR) and 95% confidence intervals (CI). Sources of heterogeneity were analyzed by subgroup and meta-regression analyses. The following categories of sepsis were analyzed: EOS, LOS, unspecified onset sepsis (UOS), culture-proven, and clinical sepsis. CA was subdivided into clinical and histological chorioamnionitis. Funisitis was also analyzed. We found 3,768 potentially relevant studies, of which 107 met the inclusion criteria (387,321 infants; 44,414 cases of CA). Meta-analysis showed an association between any CA and any EOS (OR 4.29, CI 3.63-5.06), any LOS (OR 1.29, CI 1.11-1.54), and any UOS (OR 1.59, CI 1.11-1.54). Subgroup analysis showed that CA was associated with culture-proven EOS (OR 4.69, CI 3.91-5.56), clinical EOS (OR 3.58, CI 1.90-6.76), and culture-proven LOS (OR 1.31, CI 1.12-1.53), but not with clinical LOS (OR 1.52, CI 0.78-2.96). The presence of funisitis did not increase the risk of either EOS or LOS when compared with CA without funisitis. CA-exposed infants had lower gestational age (-1.11 weeks, CI -1.37 to -0.84) than the infants not exposed to CA. Meta-regression analysis showed that the lower gestational age of the CA group correlated with the association between CA and LOS but not with the association between CA and EOS. In conclusion, our data suggest that the positive association between chorioamnionitis and LOS may be modulated by the effect of chorioamnionitis on gestational age.

A Genome-Wide Analysis of Clinical Chorioamnionitis among Preterm Infants

OBJECTIVE

To identify single nucleotide polymorphisms (SNPs) associated with clinical chorioamnionitis among preterm infants.

STUDY DESIGN

We reanalyzed a genome-wide association study (GWAS) from preterm newborns at less than 30 weeks' gestation. Cases and control definitions were determined using administrative records. There were 213 clinical chorioamnionitis cases and 707 clinically uninfected controls. We compared demographic and clinical outcomes of cases and controls. We performed a GWAS and compared the distribution of SNPs from the background genes and from the immunome genes. We used a Wilcoxon's rank-sum test to compare the SNPs normalized odds ratio and used odds ratios and p-values to determine candidate genes.

RESULTS

Infants affected by clinical chorioamnionitis were more likely to have periventricular leukomalacia, high-grade retinopathy, and high-grade intraventricular hemorrhage (IVH). Although a GWAS did not identify SNPs associated with clinical chorioamnionitis at the genome-wide significance level, a direct test on the exonic variants in the human immunome revealed their significant increase of risk in clinical chorioamnionitis.

CONCLUSION

Among very preterm infants, clinical chorioamnionitis was associated with periventricular leukomalacia, high-grade retinopathy, and IVH. Our analysis of variants in the human immunome indicates an association with clinical chorioamnionitis in very preterm pregnancies.

Influence of single nucleotide polymorphisms (SNPs) in immunoregulatory genes in the morbidity of preterm newborns

Background: Prematurity is the main cause of perinatal and neonatal morbidity and mortality worldwide. Single nucleotide polymorphisms (SNPs) have been associated with the pathogenesis of morbidities in preterm neonates. We aimed to investigate the association between SNPs in regulatory genes of innate immune response IL1B, IL6, IL6R, IL10, TNFA, TNFRII, TLR2 and TLR4 and neonatal/infant morbidities in preterm newborns.Methods: Oral swabs were collected from 272 newborns (91 preterm and 181 at term) seen at Botucatu Medical School, Unesp, between 2013 and 2014 and SNPs were identified using Taqman^® Genotyping Assays. Medical records were examined to obtain data regarding neonatal/infant morbidity. Stepwise binomial logistic regression models were used to explain the morbidities.Results: Minor neonatal morbidity was influenced by the clinical parameters of maternal age and newborn weight at birth and by the presence of the allele IL6R2 C (rs2228145) while major neonatal morbidity was only influenced by gestational age. Minor infant morbidity was associated with the allele TLR2 T (rs4696480) and major infant morbidity was associated with gestational age and presence of IL6R2 C.Conclusion: The presence of SNPs that exacerbate the inflammatory response increases the susceptibility to neonatal and infant morbidity.

Association of Gene Polymorphism of Bactericidal Permeability Increasing Protein Rs4358188, Cluster of Differentiation 14 Rs2569190, Interleukin 1β Rs1143643 and Matrix Metalloproteinase-16 Rs2664349 with Neonatal Sepsis

BACKGROUND

Neonatal sepsis is a health problem because it causes serious morbidity and mortality in neonate intensive care units. The susceptibility of neonates occurs due to the immaturity of immune system development as well as due to maternal and environmental risk factors that can cause infection. Identification of genetic variation in genes involved in the inflammatory process can help clarify the pathophysiology of sepsis in high-risk patients, useful for the development of new diagnostic tools, and specific management plans for more accurate predictions of patient's prognosis.

AIM

This study aims to determine the association between gene polymorphism of BPI rs4358188, CD14 rs2569190, IL1β rs1143643 or MMP16 rs2664349 and the incidence of neonatal sepsis.

METHODS

Cross-sectional observational studies with genomic DNA samples from infants with sepsis and non-sepsis which were stored according to the standard storage of genetic materials in the Biomedical Laboratory of Faculty of Medicine Universitas Andalas Padang City, Indonesia. This study is part of a previous study by Rukmono P. Continued with PCR examination, sequencing and bioinformatics analysis.

RESULTS

Only IL1β rs1143643 G > A gene polymorphism was associated with the incidence of neonatal sepsis and was statistically significant (p = 0.017). No significant association was found between gene polymorphisms of BPI rs4358188 G > T, CD14 rs2569190 A>G or MMP16 rs2664349 G > A and neonatal sepsis (p > 0.05).

CONCLUSION

Gene polymorphism of IL1β rs1143643 G > A is associated with the incidence of neonatal sepsis.

Genetic variants in Forkhead box O1 associated with predisposition to sepsis in a Chinese Han population

Background

Genetic variant is one of the causes of sepsis patients’ mortality. Now, many studies have identified several SNPs related to sepsis. However, none of these studies were identified in a genome-wide way. We aimed to detect genetic polymorphisms of sepsis patients.

Methods

The blood samples of eight normal controls and ten sepsis patients were collected for whole exome sequencing. Then, Single Nucleotide Polymorphisms (SNPs) were selected according to quality score and number of sepsis patients who had this variants. Synonymous mutations were removed. Genes including these remaining variants were used for functional analyses. After analyses, the remaining SNPs and indels were validated in 149 normal controls and 156 sepsis patients. Finally, serum levels of proteins coded by genes including these SNPs were evaluated.

Results

After whole exome sequencing, 97 SNPs and one indel site were left. Then, functional screening was performed. Only seven SNPs were used for further validation. As a result, the rs2721068 in dominant model and rs17446614 in recessive model were associated with sepsis, and the ORs of these two SNPs were 3.24 (95%CI, 1.25, 8.44) and 0.47 (0.026, 0.88), respectively. These two SNPs were both located in Forkhead box O1 (FOXO1) gene. For rs2721068 (T/T, T/C-C/C) and rs17446614 (A/A-A/G, G/G), serum levels of foxo1 in sepsis patients were both significantly lower in normal controls.

Conclusions

We firstly reported that the rs2721068 and rs17446614 were correlated to genetic predisposition to sepsis.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4330-7) contains supplementary material, which is available to authorized users.

TLR5 decoy receptor as a novel anti-amyloid therapeutic for Alzheimer's disease

Chakrabarty et al. show that human TLR5 ectodomain reduces amyloid β (Aβ) plaques by direct interaction with Aβ, demonstrating the feasibility of such immune decoy receptor strategies as potential biotherapies in Alzheimer’s disease.

There is considerable interest in harnessing innate immunity to treat Alzheimer’s disease (AD). Here, we explore whether a decoy receptor strategy using the ectodomain of select TLRs has therapeutic potential in AD. AAV-mediated expression of human TLR5 ectodomain (sTLR5) alone or fused to human IgG4 Fc (sTLR5Fc) results in robust attenuation of amyloid β (Aβ) accumulation in a mouse model of Alzheimer-type Aβ pathology. sTLR5Fc binds to oligomeric and fibrillar Aβ with high affinity, forms complexes with Aβ, and blocks Aβ toxicity. Oligomeric and fibrillar Aβ modulates flagellin-mediated activation of human TLR5 but does not, by itself, activate TLR5 signaling. Genetic analysis shows that rare protein coding variants in human TLR5 may be associated with a reduced risk of AD. Further, transcriptome analysis shows altered TLR gene expression in human AD. Collectively, our data suggest that TLR5 decoy receptor–based biologics represent a novel and safe Aβ-selective class of biotherapy in AD.

Association between Tumor Necrosis Factor-α Promoter -308 G/A Polymorphism and Early Onset Sepsis in Preterm Infants

Early-onset neonatal sepsis (EOS) is diagnosed during the first 7 days of neonatal life and is the major cause of morbidity and mortality among preterm infants. Genetic predisposition may have an impact on EOS susceptibility and outcome. The aim of our study was to explore the association between TNF-α -308 G/A or IL-6 -174 G/C gene polymorphism and the susceptibility and outcome of EOS in preterm infants. The study included 471 preterm infants: 282 with EOS (151 with culture proven sepsis and 131 with clinical sepsis) and 189 without infection (control group). TNF-α -308 G/A and IL-6 -174 G/C were genotyped using Real-time RCR method. We observed significantly higher frequency of A allele of TNF-α -308 G/A polymorphism in blood culture proven EOS (p = 0.017) or clinical EOS (p = 0.025) compared with the control group. Logistic regression confirmed significant association between TNF-α -308 GA+AA genotypes and development of culture proven EOS (B = -0.718, p = 0.013) or clinical EOS (B = -0.602, p = 0.027). No significant differences in IL6 -174G/C alleles or genotypes distribution have been observed between culture proven EOS group, clinical EOS group and the control group. An association between TNF-α -308 G/A or IL-6 -174 G/C genotypes and EOS lethal outcome was not observed (p = 0.652 and p = 0.384, respectively). According to our analysis of large cohort of preterm infants with clearly defined EOS groups, the TNF-α -308 A allele may be a risk factor for the EOS occurrence.

Association of a placental Interleukin-6 genetic variant (rs1800796) with DNA methylation, gene expression and risk of acute chorioamnionitis

BACKGROUND

Acute chorioamnionitis (aCA), inflammation of the placenta and fetal membranes, is a frequently reported lesion in preterm deliveries. Genetic variants in innate immune system genes such as Interleukin-6 (IL6) may contribute to the placenta's inflammatory response, thus predisposing some pregnancies to aCA. These genetic variants may modulate molecular processes such as DNA methylation and gene expression, and in turn might affect susceptibility to aCA. Currently, there is remarkably little research on the role of fetal (placental) genetic variation in aCA. We aimed to explore the associations between genetic variants in candidate immune-system genes and susceptibility towards inflammatory responses in the placenta, which is linked to a strong inflammatory response in the newborn.

METHODS

DNA samples from 269 placentas (72 aCA cases, 197 non-aCA cases) were collected for this study. Samples were genotyped at 55 ancestry informative markers (AIMs) and 16 additional single nucleotide polymorphisms (SNPs) in 12 candidate innate immune system genes using the Sequenom iPLEX Gold Assay. Publicly available datasets were used to obtain DNA methylation (GSE100197, GSE74738, GSE115508, GSE44667, GSE98224) and gene expression data (GSE44711, GSE98224).

RESULTS

Differences in IL6 placental allele frequencies were associated with aCA (rs1800796, p = 0.04) with the CC genotype specifically implicated (OR = 3.1; p = 0.02). In a subset of the placental samples (n = 67; chorionic villi), we showed that the IL6 SNP (rs1800796) was associated with differential DNA methylation in five IL6-related CpG sites (cg01770232, cg02335517, cg07998387, cg13104385, and cg0526589), where individuals with a CC genotype showed higher DNA methylation levels than individuals carrying the GG genotype. Using two publicly available datasets, we observed that the DNA methylation levels at cg01770232 negatively correlated with IL6 gene expression in the placenta (r = - 0.67, p < 0.004; r = - 0.56, p < 2.937e-05).

CONCLUSIONS

We demonstrated that the minor C allele at the IL6 SNP (rs1800796), which is largely limited to East Asian populations, is associated with the presence of aCA. This SNP was associated with increased DNA methylation at a nearby MEPC2 binding site, which was also associated with decreased expression of IL6 in the placenta. Decreased expression of IL6 may increase vulnerability to microbial infection. Additional studies are required to confirm this association in Asian populations with larger sample sizes.

DNA methylation profiling of acute chorioamnionitis-associated placentas and fetal membranes: insights into epigenetic variation in spontaneous preterm births

BACKGROUND

Placental inflammation, often presenting as acute chorioamnionitis (aCA), is commonly associated with preterm birth. Preterm birth can have both immediate and long-term adverse effects on the health of the baby. Developing biomarkers of inflammation in the placenta can help to understand its effects and potentially lead to new approaches for rapid prenatal diagnosis of aCA. We aimed to characterize epigenetic variation associated with aCA in placenta (chorionic villi) and fetal membranes (chorion and amnion) to better understand how aCA may impact processes that lead to preterm birth. This study lays the groundwork for development of novel biomarkers for aCA.

METHODS

Samples from 44 preterm placentas (chorionic villi) as well as matched chorion and amnion for 16 of these cases were collected for this study. These samples were profiled using the Illumina Infinium HumanMethylation850 BeadChip to measure DNA methylation (DNAm) at 866,895 CpGs across the genome. An additional 78 placental samples were utilized to independently validate the array findings by pyrosequencing.

RESULTS

Using a false discovery rate of < 0.15 and average group difference in DNAm of > 0.05, 66 differentially methylated (DM) CpG sites were identified between aCA cases and non-aCA cases in chorionic villi. For the majority of these 66 DM CpGs, the DNAm profile of the aCA cases as compared to the non-aCA cases trended in the direction of the blood cell DNAm. Interestingly, neutrophil-specific DNAm signatures, but not those associated with other immune cell types, were capable of separating aCA cases from the non-aCA cases.

CONCLUSIONS

Our results suggest that aCA-associated placentas showed altered DNAm signatures that were not observed in the absence of aCA. This DNAm profile is consistent with the activation of the innate immune response in the placenta and/or reflect increase in neutrophils as a response to inflammation.

In silico investigation of the molecular effects caused by R123H variant in secretory phospholipase A2-IIA associated with ARDS

Phospholipase A2-IIA catalyzes the hydrolysis of the sn-2 ester of glycerophospholipids. A rare c.428G > A (p.Arg143His) variant in PLA2G2A gene was found in two infants affected by acute respiratory distress syndrome (ARDS) by whole coding region and exon/intron boundaries sequencing. To obtain insights into the possible molecular effects of the rare R123H mutation in secretory PLA2-IIA (sPLA2-IIA), molecular modelling, molecular dynamics (MD) using principal component analysis (PCA) and continuum electrostatic calculations were conducted on the crystal structure of the wild type protein and on a generated model structure of the R123H mutant. Analysis of MD trajectories indicate that the overall stability of the protein is not affected by this mutation but nevertheless the catalytically crucial H-bond between Tyr51 and Asp91 as well as main electrostatic interactions in the region close to the mutation site are altered. PCA results indicate that the R123H replacement alter the internal molecular motions of the enzyme and that collective motions are increased. Electrostatic surface potential studies suggest that after mutation the interfacial binding to anionic phospholipid membranes and anionic proteins may be changed. The strengthening of electrostatic interactions may be propagated into the active site region thus potentially affecting the substrate recognition and enzymatic activity. Our findings provide the basis for further investigation and advances our understanding of the effects of mutations on sPLA2 structure and function.

The expression of Toll-like receptor 5 in preterm histologic chorioamnionitis

Spontaneous preterm birth is often caused by chorioamnionitis. Toll-like receptors (TLRs) have a role in the response of the innate immune system. The role of TLR5 in chorioamnionitis remains unclear: however, TLR5 was reported to have a significantly stronger effect on the induction of interleukin (IL)-6 when compared with other TLRs in amniotic epithelial cells. The aim of this study was to investigate TLR5 expression in placentas with preterm histologic chorioamnionitis (HCA). The expression levels of TLR5 were evaluated in the amnions, chorions, deciduae and villi with and without HCA using immunohistochemistry. The co-localization of IL-6 or IL-8 with TLR5 was examined by immunofluorescence. The production of IL-6 was examined in primary tissue cultured fetal membranes treated with and without the TLR5 agonist. The protein expression of TLR5 was significantly increased in amnions with HCA (p<0.05) and showed a trend toward an increase in chorions with HCA, whereas no significant difference was detected in the villi and decidua. TLR5 co-localized with IL-6 and IL-8 in amnions and chorions. IL-6 showed a significant increase (p<0.05) with the TLR5 agonist. These results suggest that TLR5 plays a role in the pathogenesis of preterm HCA and IL-6 production.

Genome-wide association study of sepsis in extremely premature infants

OBJECTIVE

To identify genetic variants associated with sepsis (early-onset and late-onset) using a genome-wide association (GWA) analysis in a cohort of extremely premature infants.

STUDY DESIGN

Previously generated GWA data from the Neonatal Research Network's anonymised genomic database biorepository of extremely premature infants were used for this study. Sepsis was defined as culture-positive early-onset or late-onset sepsis or culture-proven meningitis. Genomic and whole-genome-amplified DNA was genotyped for 1.2 million single-nucleotide polymorphisms (SNPs); 91% of SNPs were successfully genotyped. We imputed 7.2 million additional SNPs. p Values and false discovery rates (FDRs) were calculated from multivariate logistic regression analysis adjusting for gender, gestational age and ancestry. Target statistical value was p<10-5. Secondary analyses assessed associations of SNPs with pathogen type. Pathway analyses were also run on primary and secondary end points.

RESULTS

Data from 757 extremely premature infants were included: 351 infants with sepsis and 406 infants without sepsis. No SNPs reached genome-wide significance levels (5×10-8); two SNPs in proximity to FOXC2 and FOXL1 genes achieved target levels of significance. In secondary analyses, SNPs for ELMO1, IRAK2 (Gram-positive sepsis), RALA, IMMP2L (Gram-negative sepsis) and PIEZO2 (fungal sepsis) met target significance levels. Pathways associated with sepsis and Gram-negative sepsis included gap junctions, fibroblast growth factor receptors, regulators of cell division and interleukin-1-associated receptor kinase 2 (p values<0.001 and FDR<20%).

CONCLUSIONS

No SNPs met genome-wide significance in this cohort of extremely low birthweight infants; however, areas of potential association and pathways meriting further study were identified.

Early Prediction of Sepsis Incidence in Critically Ill Patients Using Specific Genetic Polymorphisms

Several diagnostic methods for the evaluation and monitoring were used to find out the pro-inflammatory status, as well as incidence of sepsis in critically ill patients. One such recent method is based on investigating the genetic polymorphisms and determining the molecular and genetic links between them, as well as other sepsis-associated pathophysiologies. Identification of genetic polymorphisms in critical patients with sepsis can become a revolutionary method for evaluating and monitoring these patients. Similarly, the complications, as well as the high costs associated with the management of patients with sepsis, can be significantly reduced by early initiation of intensive care.

Investigation of association between IL-8 serum levels and IL8 polymorphisms in Chinese patients with sepsis

OBJECTIVE

To assess the clinical relevance of IL8 gene polymorphisms in patients with sepsis and its association with systemic IL-8 levels.

METHODS

PCR and DNA sequencing were used to examine the polymorphism of IL8 in 152 patients with sepsis and in 199 healthy volunteers in China. The distribution frequencies of the genotype and allele were compared among different groups. The serum IL-8 was measured by ELISA and analyzed in relation to polymorphisms of IL8.

RESULTS

The homozygote TT genotype and T allele of rs4073 (genotype: p=0.01, allele: p=0.002), the homozygote CC genotype and C allele (genotype: p=0.03, allele: p=0.003) of rs2227306, homozygote AA genotype and A allele of re1126647 (genotype: p=0.01, allele: p=0.002) were associated with susceptibility to sepsis in males. Serum IL-8 levels were significantly increased in patients with sepsis but showed no correlation with IL8 rs4073, rs2227306 and rs1126647 polymorphisms.

CONCLUSIONS

The male population carrying the homozygote TT genotype and T allele of rs4073, the homozygote CC genotype and C allele of rs2227306 and homozygote AA genotype and A allele of rs1126647 are more susceptible to sepsis, suggesting there is a protective effect in females carrying these genotypes and alleles respectively. There was no association between rs4073, rs2227306 and rs1126647 polymorphisms and serum levels of IL-8 in patients with sepsis.

Use of systems biology to decipher host-pathogen interaction networks and predict biomarkers

In systems biology, researchers aim to understand complex biological systems as a whole, which is often achieved by mathematical modelling and the analyses of high-throughput data. In this review, we give an overview of medical applications of systems biology approaches with special focus on host-pathogen interactions. After introducing general ideas of systems biology, we focus on (1) the detection of putative biomarkers for improved diagnosis and support of therapeutic decisions, (2) network modelling for the identification of regulatory interactions between cellular molecules to reveal putative drug targets and (3) module discovery for the detection of phenotype-specific modules in molecular interaction networks. Biomarker detection applies supervised machine learning methods utilizing high-throughput data (e.g. single nucleotide polymorphism (SNP) detection, RNA-seq, proteomics) and clinical data. We demonstrate structural analysis of molecular networks, especially by identification of disease modules as a novel strategy, and discuss possible applications to host-pathogen interactions. Pioneering work was done to predict molecular host-pathogen interactions networks based on dual RNA-seq data. However, currently this network modelling is restricted to a small number of genes. With increasing number and quality of databases and data repositories, the prediction of large-scale networks will also be feasible that can used for multidimensional diagnosis and decision support for prevention and therapy of diseases. Finally, we outline further perspective issues such as support of personalized medicine with high-throughput data and generation of multiscale host-pathogen interaction models.

Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis

In individuals with sepsis, the infecting microbes are commonly viewed as generic inducers of inflammation while the host background is considered the primary variable affecting disease progression and outcome. To study the effects of bacterial strain differences on the maladaptive immune responses that are induced during sepsis, we employed a novel zebrafish embryo infection model using extraintestinal pathogenic Escherichia coli (ExPEC) isolates. These genetically diverse pathogens are a leading cause of sepsis and are becoming increasingly dangerous because of the rise of multidrug-resistant strains. Zebrafish infected with ExPEC isolates exhibit many of the pathophysiological features seen in septic human patients, including dysregulated inflammatory responses (cytokine storms), tachycardia, endothelial leakage, and progressive edema. However, only a limited subset of ExPEC isolates can trigger a sepsis-like state and death of the host when introduced into the bloodstream. Mirroring the situation in human patients, antibiotic therapy reduced ExPEC titers and improved host survival rates but was only effective within limited time frames that varied, depending on the infecting pathogen. Intriguingly, we find that phylogenetically distant but similarly lethal ExPEC isolates can stimulate markedly different host transcriptional responses, including disparate levels of inflammatory mediators. These differences correlate with the amounts of bacterial flagellin expression during infection, as well as differential activation of Toll-like receptor 5 by discrete flagellar serotypes. Altogether, this work establishes zebrafish as a relevant model of key aspects of human sepsis and highlights the ability of genetically distinct ExPEC isolates to induce divergent host responses independently of baseline host attributes. IMPORTANCE Sepsis is a life-threatening systemic inflammatory condition that is initiated by the presence of microorganisms in the bloodstream. In the United States, sepsis due to ExPEC and other pathogens kills well over a quarter of a million people each year and is associated with tremendous health care costs. A high degree of heterogeneity in the signs and symptomology of sepsis makes this disease notoriously difficult to effectively diagnose and manage. Here, using a zebrafish model of sepsis, we find that similarly lethal but genetically distinct ExPEC isolates can elicit notably disparate host responses. These variances are in part due to differences in the levels and types of flagellin that are expressed by the infecting ExPEC strains. A better understanding of the variable impact that bacterial factors like flagellin have on host responses during sepsis could lead to improved diagnostic and therapeutic approaches to these often deadly infections. Podcast: A podcast concerning this article is available.

Genetic polymorphism in postoperative sepsis after open heart surgery in infants

Background

Sepsis is one of the complications following open heart surgery. Toll-like receptor 2 and toll-interacting protein polymorphism influence the immune response after open heart surgery. This study aimed to assess the genetic distribution of toll-like receptor 2 N199N and toll-interacting protein rs5743867 polymorphism in the development of postoperative sepsis.

Methods

A prospective cohort study was conducted in 108 children <1-year old who underwent open heart surgery with a Basic Aristotle score ≥6. Patients with an accompanying congenital anomaly, human immunodeficiency virus infection, or history of previous open heart surgery were excluded. The patients’ nutritional status and genetic polymorphism were assessed prior to surgery. The results of genetic polymorphism were obtained through genotyping. Patients’ ages on the day of surgery and cardiopulmonary bypass times were recorded. The diagnosis of sepsis was established according to Surviving Sepsis Campaign criteria.

Results

Postoperative sepsis was observed in 21% of patients. There were 92.6% patients with toll-like receptor 2 N199N polymorphism and 52.8% with toll-interacting protein rs5743867 polymorphism.

Conclusions

Toll-like receptor 2 N199N polymorphism tends to increase the risk of sepsis (odds ratio = 1.974; 95% confidence interval: 0.23–16.92; p = 0.504), while toll-interacting protein rs5743867 polymorphism tends to decrease the risk of sepsis (odds ratio = 0.496; 95% confidence interval: 0.19–1.27; p = 0.139) in infants <1-year old undergoing complex open heart surgery.

Ancestry informative markers and selected single nucleotide polymorphisms in immunoregulatory genes on preterm labor and preterm premature rupture of membranes: a case control study

Background

A genetic predisposition to Preterm Labor (PTL) and Preterm Premature Rupture of Membranes (PPROM) has been suggested; however the relevance of polymorphisms and ancestry to susceptibility to PTL and PPROM in different populations remains unclear. The aim of this study was to evaluate the contribution of maternal and fetal SNPs in the IL1B, IL6, IL6R, TNFA, TNFR, IL10, TLR2, TLR4, MMP9, TIMP1 and TIMP2 genes and the influence of ancestry background in the susceptibility to PTL or PPROM in Brazilian women.

Methods

Case–control study conducted at a tertiary hospital in São Paulo State, Brazil. We included women with PTL or PPROM and their babies (PTL: 136 women and 88 babies; PPROM: 65 women and 44 babies). Control group included 402 mother-babies pairs of term deliveries. Oral swabs were collected for identification of AIMs by fragment analysis and SNPs by Taqman® SNP Genotyping Assays and PCR. Linkage Disequilibrium and Hardy-Weinberg proportions were evaluated using Genepop 3.4. Haplotypes were inferred using the PHASE algorithm. Allele, genotype and haplotype frequencies were compared by Fisher’s exact test or χ² and Odds Ratio. Logistic regression was performed. Clinical and sociodemographic data were analyzed by Fisher’s exact test and Mann–Whitney.

Results

PTL was associated with European ancestry and smoking while African ancestry was protective. The fetal alleles IL10-592C (rs800872) and IL10-819C (rs1800871) were also associated with PTL and the maternal haplotype TNFA-308G-238A was protective. Maternal presence of IL10-1082G (rs1800896) and TLR2A (rs4696480) alleles increased the risk for PPROM while TNFA-238A (rs361525) was protective. Family history of PTL/PPROM was higher in cases, and time to delivery was influenced by IL1B-31T (rs1143627) and TLR4-299G (rs4986790).

Conclusion

There is an association between European ancestry and smoking and PTL in our Brazilian population sample. The presence of maternal or fetal alleles that modify the inflammatory response increase the susceptibility to PTL and PPROM. The family history of PTL/PPROM reinforces a role for genetic polymorphisms in susceptibility to these outcomes.

Significant roles played by interleukin-10 in outcome of pregnancy

Imbalanced immune responses against fetus alloantigens can lead to abnormality in pregnancy. Interleukin-10 (IL-10) plays key roles in regulation of immune responses against self and foreign antigens to induce tolerance to these antigens. Therefore, alteration in expression of IL-10 during pregnancy may result in several pathologic conditions such as preterm labor. IL-10 leads to a normal pregnancy via several molecular mechanisms including development of tolerogenic dendritic cells, T regulatory lymphocytes and activation of the JAK1/STAT3 pathway in the target cells. This review has collected recent data regarding the status of IL-10 expression during term and preterm deliveries and also its molecular mechanisms that lead to a normal pregnancy.

Human Milk Components Modulate Toll-Like Receptor-Mediated Inflammation

Toll-like receptor (TLR) signaling is central to innate immunity. Aberrant expression of TLRs is found in neonatal inflammatory diseases. Several bioactive components of human milk modulate TLR expression and signaling pathways, including soluble toll-like receptors (sTLRs), soluble cluster of differentiation (sCD) 14, glycoproteins, small peptides, and oligosaccharides. Some milk components, such as sialyl (α2,3) lactose and lacto-N-fucopentaose III, are reported to increase TLR signaling; under some circumstances this might contribute toward immunologic balance. Human milk on the whole is strongly anti-inflammatory, and contains abundant components that depress TLR signaling pathways: sTLR2 and sCD14 inhibit TLR2 signaling; sCD14, lactadherin, lactoferrin, and 2'-fucosyllactose attenuate TLR4 signaling; 3'-galactosyllactose inhibits TLR3 signaling, and β-defensin 2 inhibits TLR7 signaling. Feeding human milk to neonates decreases their risk of sepsis and necrotizing enterocolitis. Thus, the TLR regulatory components found in human milk hold promise as benign oral prophylactic and therapeutic treatments for the many gastrointestinal inflammatory disorders mediated by abnormal TLR signaling.

What is the basis for a genetic approach in neonatal disorders?

Gene-environment interactions likely account for some degree of the variance in response rates that are clinically observed with antenatal corticosteroids, breast milk prophylaxis, surfactant administration, early recognition and treatment of sepsis, utility of non-invasive ventilation, and judicious exposure to supplemental oxygen. While these therapies and practice guidelines have significantly decreased overall neonatal mortality in the NICU, they have not made a marked impact on the frequency and severity of conditions such as bronchopulmonary dysplasia (BPD), necrotizing enterocolitis, and periventricular leukomalacia. One possible explanation is that genetic factors in the neonate modulate response to external intervention or preventative agents, culminating in variable levels of injury and different degrees of resolution and repair. Gene-environment explanations are supported by the observed heritability of BPD in twin studies, but they do not differentiate the interactions between neonate and offending toxin or pathogen, from interactions between neonate and intervention or therapeutic agent. Likely, both kinds of interactions are important in determining outcome.

Elucidating the role of genomics in neonatal sepsis

Sepsis is a major cause of neonatal morbidity and mortality, especially in vulnerable preterm populations. Immature immune defenses, and environmental and maternal factors contribute to this risk, with as many as a third of very preterm infants experiencing sepsis during their stay in the neonatal intensive care unit (NICU). Epidemiologic and twin studies have suggested that there is a genetic contribution to sepsis predilection. Several investigators have conducted candidate gene association studies on variants of specific interest and potential functional significance in neonatal sepsis. In this review, we describe details of studies that have evaluated genetic susceptibility in neonatal sepsis, and summarize findings from a review of candidate gene association studies.

Predictive monitoring for sepsis and necrotizing enterocolitis to prevent shock

Despite vigilant clinical assessment of infants in the neonatal intensive care unit (NICU), diagnosis of sepsis and necrotizing enterocolitis often does not occur until an infant has significant hemodynamic compromise. Predictive monitoring involves analysis of vital signs and other clinical data to identify infants at highest risk and to detect early-stage illness, leading to timelier treatment and improved outcomes. The first vital-sign predictive monitoring device developed for sepsis detection in babies in the NICU is the heart rate characteristics index (HeRO) monitor, which continuously analyzes the electrocardiogram signal for low heart rate variability and transient decelerations. Use of this monitor in very low birth weight infants (<1500 g) was shown in a large multicenter randomized clinical trial to significantly reduce mortality. The purpose of this review is (1) to summarize the physiologic changes in neonatal sepsis and progression to shock, (2) to review efforts toward risk stratification for sepsis shortly after birth based on demographic and physiologic scoring systems, (3) to describe development and implementation of heart rate characteristics monitoring and other important aspects of sepsis early warning systems, and (4) to provide an overview of current research analyzing multiple vital signs and other clinical variables in an attempt to develop even more effective predictive monitoring devices and systems.

High serum trypsin levels and the -409 T/T genotype of PRSS1 gene are susceptible to neonatal sepsis

Neonatal sepsis remains an important and common cause of morbidity and mortality among newborn infants, especially in developing countries. The aim of the present study was to determine whether serum trypsin levels and genotypes of cationic trypsinogen (PRSS1) gene could be served as markers for predicting neonatal sepsis. The serum trypsin levels and genotypes of PRSS1 were examined in both 50 infants with infection during neonatal period and 56 healthy neonates as controls. The infected infants were further subdivided into infants with sepsis group (n=18) and infected infants without sepsis (n=32). The genotype of PRSS1 was analyzed by direct sequencing, and the serum trypsin level was measured by immunoassay. It showed that the median value of serum trypsin was significantly higher in infected infants (31.90 ng/mL) than in controls (12.85 ng/mL; P=0.030). More importantly, sepsis subgroup (50.95 ng/mL) had significantly higher median serum trypsin than infected infants without sepsis subgroup (19.10 ng/mL) and controls (12.85 ng/mL) (P=0.015 and P=0.002, respectively). Additionally, the median serum trypsin levels were found significantly higher in infants who had T/T (37.90 ng/mL) genotype of PRSS1 compared with those who had C/T genotype (12.80 ng/mL; P=0.005). This study suggested that serum trypsin and rs10273639 C/T of PRSS1 were revealed to be novel markers for predicting neonatal sepsis.

Interleukin-10 rs2227307 and CXCR2 rs1126579 polymorphisms modulate the predisposition to septic shock

Despite major improvements in its treatment and diagnosis, sepsis is still a leading cause of death and admittance to the intensive care unit (ICU). Failure to identify patients at high risk of developing septic shock contributes to an increase in the sepsis burden and rapid molecular tests are currently the most promising avenue to aid in patient risk determination and therapeutic anticipation. The primary goal of this study was to evaluate the genetic susceptibility that affects sepsis outcome in 72 sepsis patients admitted to the ICU. Seven polymorphisms were genotyped in key inflammatory response genes in sepsis, including tumour necrosis factor-α, interlelukin (IL)-1β, IL-10, IL-8, Toll-like receptor 4, CXCR1 and CXCR2. The primary finding showed that patients who were homozygous for the major A allele in IL-10 rs1800896 had almost five times higher chance to develop septic shock compared to heterozygotes. Similarly, selected clinical features and CXCR2 rs1126579 single nucleotide polymorphisms modulated septic shock susceptibility without affecting survival. These data support the hypothesis that molecular testing has clinical usefulness to improve sepsis prognostic models. Therefore, enrichment of the ICU portfolio by including these biomarkers will aid in the early identification of sepsis patients who may develop septic shock.

Neonatal infections in Saudi Arabia: Association with cytokine gene polymorphisms

In recent years, many studies have reported potential associations between cytokine gene polymorphisms and the development, course, and outcome of sepsis, often with apparently conflicting results. The objective of this study was to investigate single nucleotide polymorphism (SNP) in the interleukin (IL)-1β –31 T/C, IL-6 –174 G/C, tumor necrosis factor α (TNF-α) –308 G/A, and interferon γ (IFN-γ) +874 A/T genes for their possible association with susceptibility to early onset sepsis (EOS) in Saudi newborn infants. A total of 205 newborn infants aged 1-2 days were consecutively enrolled onto the study having met the inclusion criteria (as per the research protocol). DNA was extracted from filter papers using the Chelex-100 method. The cytokines SNP were genotyping using Taqman 5’ nuclease allelic discrimination. For cytokine measurements we used the commercially available Enzyme-Linked Immunosorbent Assay (ELISA) kit. Our results show that the circulating IL-1β, IL-6, TNF-α, and IFN-γ were significantly (p < 0.001) elevated in EOS patients compared to suspected and sepsis-free control groups; and IL-1β –31C, IL-6 –174G, TNF-α –308G, and IFN-γ +874A alleles were associated with EOS in Saudi infants. In conclusion, analysis of cytokines concentrations and SNP for the four tested genes can be used as a predictor of sepsis outcome in newborns.

Combined effect of TLR2 gene polymorphism and early life stress on the age at onset of bipolar disorders

Gene-environment interactions may play an important role in modulating the impact of early-life stressful events on the clinical course of bipolar disorder (BD), particularly associated to early age at onset. Immune dysfunction is thought to be an important mechanism linking childhood trauma with early-onset BD, thus the genetic diversity of immune-related loci may account for an important part of the interindividual susceptibility to this severe subform. Here we investigated the potential interaction between genetic variants of Toll-like receptors 2 (TLR2) and 4 (TLR4), major innate immune response molecules to pathogens, and the childhood trauma questionnaire (CTQ) in age at onset of BD. We recruited 531 BD patients (type I and II or not otherwise specified), genotyped for the TLR2 rs4696480 and rs3804099 and TLR4 rs1927914 and rs11536891 single-nucleotide polymorphisms and recorded for history of childhood trauma using the CTQ. TLR2 and TLR4 risk genotype carrier state and history of childhood emotional, physical and sexual abuses were evaluated in relation to age at onset as defined by the age at first manic or depressive episode. We observed a combined effect of TLR2 rs3804099 TT genotype and reported sexual abuse on determining an earlier age at onset of BD by means of a Kaplan-Meier survival curve (p = 0.002; corrected p = 0.02). Regression analysis, however, was non-significant for the TLR2-CTQ sexual abuse interaction term. The negative effects of childhood sexual abuse on age at onset of BD may be amplified in TLR2 rs3804099 risk genotype carriers through immune-mediated pathways. Clinical characteristics of illness severity, immune phenotypes and history of early life infectious insults should be included in future studies involving large patient cohorts.

Neonatal levels of inflammatory markers and later risk of schizophrenia

BACKGROUND

There is a long-standing interest in investigating the impact of early-life immune abnormalities on later onset of psychosis. The aim of this study was to assess inflammatory marker levels in neonatal dried blood spots and their association with later risk of schizophrenia.

METHODS

This nested case-control study included 995 cases and 980 control subjects. Cases were identified using the Danish Psychiatric Central Register. Control subjects of same age and sex were identified using the Danish Civil Registration System. Samples for the identified individuals were retrieved from the Danish Neonatal Screening Biobank. Concentrations of 17 inflammatory markers were measured in eluates from dried blood spots using a bead-based multiplex assay. Incidence rate ratios were calculated using conditional logistic regression. Principal component analysis was used to capture the overall variation in the inflammatory markers' concentrations.

RESULTS

No significant differences were found for any of the analyzed interleukins. We did not find any association with schizophrenia for any of the other examined inflammatory markers.

CONCLUSIONS

Our results suggest that persons who develop schizophrenia do not have higher or lower levels of the examined inflammatory markers at the time of birth. Our findings differ from the studies of maternal inflammatory changes during the antenatal period for which associations with schizophrenia have previously been demonstrated.

Genetic variation in CYB5R3 is associated with methemoglobin levels in preterm infants receiving nitric oxide therapy

BACKGROUND

In recent years, increasing numbers of preterm infants have been exposed to inhaled nitric oxide (iNO). This population has decreased methemoglobin (MetHb) reductase activity in their erythrocytes, which may increase the risk of MetHb toxicity. We sought to determine if genetic factors are associated with the observed variance in MetHb levels.

METHODS

A population of 127 preterm infants was genotyped for five single-nucleotide polymorphisms (SNPs) in the CYB5A and CYB5R3 genes. iNO dose and levels of MetHb were obtained by chart abstraction. ANOVA was performed to identify genetic associations with MetHb levels.

RESULTS

An association was found between the heterozygous genotype (GA) of rs916321 in the CYB5R3 gene and the mean of the first recorded MetHb levels in Caucasian infants (P = 0.01). This result remained significant after adjustment for the iNO dose (P = 0.009), gender (P = 0.03), multiple gestation (P = 0.03), birth weight (P = 0.02), and gestational age (P = 0.02). No significant associations were found with the other SNPs.

CONCLUSION

We demonstrate a novel genetic association with neonatal MetHb levels. Identification of genetic risk factors may be useful in determining which preterm infants are most at risk of developing MetHb toxicity with the use of iNO.

Uncomplicated diverticular disease: innate and adaptive immunity in human gut mucosa before and after rifaximin

Background/Aim. Uncomplicated diverticular disease (UDD) is a frequent condition in adults. The pathogenesis of symptoms remains unknown. Bacteria are able to interact with Toll-like receptors (TLRs) and to induce inflammation through both innate immunity and T-cell recruitment. We investigated the pattern of TLRs 2 and 4 and the intestinal homing in patients with UDD before and after a course of Rifaximin. Methods. Forty consecutive patients with UDD and 20 healthy asymptomatic subjects were enrolled. Among UDD patients, 20 were assigned to a 2-month course of treatment with Rifaximin 1.2 g/day for 15 days/month and 20 received placebo. Blood sample and colonic biopsies were obtained from patients and controls. The samples were collected and analyzed at baseline and at the end of treatment. Flow cytometry was performed using monoclonal antibodies (CD3, CD4, CD8, CD103, TCR-gamma/delta, CD14, TLR2, and TLR4). Results. In UDD, TLR2 and TLR4 expression on immune cell subpopulations from blood and mucosa of the affected colon are altered as compared with controls. Rifaximin treatment induced significant modifications of altered conditions. Conclusions. Our data show the role of TLRs in the development of inflammation in UDD. TLRs distribution is altered in UDD and these alterations are reversed after antibiotic treatment. This trial is registered with ClinicalTrials.gov: NCT02068482.

Genetic polymorphisms and sepsis in premature neonates

Identifying single nucleotide polymorphisms (SNPs) in the genes involved in sepsis may help to clarify the pathophysiology of neonatal sepsis. The aim of this study was to evaluate the relationships between sepsis in pre-term neonates and genes potentially involved in the response to invasion by infectious agents. The study involved 101 pre-term neonates born between June 2008 and May 2012 with a diagnosis of microbiologically confirmed sepsis, 98 pre-term neonates with clinical sepsis and 100 randomly selected, otherwise healthy pre-term neonates born during the study period. During the study, 47 SNPs in 18 candidate genes were genotyped on Guthrie cards using an ABI PRISM 7900 HT Fast real-time and MAssARRAY for nucleic acids instruments. Genotypes CT and TT of rs1143643 (the IL1β gene) and genotype GG of rs2664349GG (the MMP-16 gene) were associated with a significantly increased overall risk of developing sepsis (p = 0.03, p = 0.05 and p = 0.03), whereas genotypes AG of rs4358188 (the BPI gene) and CT of rs1799946 (the DEFβ1 gene) were associated with a significantly reduced risk of developing sepsis (p = 0.05 for both). Among the patients with bacteriologically confirmed sepsis, only genotype GG of rs2664349 (the MMP-16 gene) showed a significant association with an increased risk (p = 0.02). Genotypes GG of rs2569190 (the CD14 gene) and AT of rs4073 (the IL8 gene) were associated with a significantly increased risk of developing severe sepsis (p = 0.05 and p = 0.01). Genotype AG of rs1800629 (the LTA gene) and genotypes CC and CT of rs1341023 (the BPI gene) were associated with a significantly increased risk of developing Gram-negative sepsis (p = 0.04, p = 0.04 and p = 0.03). These results show that genetic variability seems to play a role in sepsis in pre-term neonates by influencing susceptibility to and the severity of the disease, as well as the risk of having disease due to specific pathogens.