Tumor necrosis factor gene polymorphisms, leukocyte function, and sepsis susceptibility in blunt trauma patients

Association between the Lymphotoxin-α A252g Gene Polymorphism and the Risk of Sepsis and Mortality: A Meta-Analysis

Background

The association between the lymphotoxin-α (LTA) A252G polymorphism and sepsis risk has been extensively studied, but the results have been controversial. This study is aimed at investigating the overall association between the LTA A252G polymorphism and the risk of sepsis/septic shock and sepsis-related mortality.

Methods

We searched the PubMed and EMBASE databases to identify studies that investigated the association between the LTA A252G polymorphism and risks of sepsis, septic shock, and mortality. The relevant data were extracted, and statistical analyses were performed using the Revman 5.0 and STATA 12 software.

Results

A total of 32 publications were included in the meta-analysis. The results demonstrated that the LTA A252G polymorphism showed no significant association with sepsis risk (GG+GA vs. AA: OR = 0.92, 95%CI = 0.79–1.07, p = 0.27) or with sepsis shock risk (GG+GA vs. AA: OR = 1.01, 95%CI = 0.84–1.22, p = 0.91). However, in the subgroup analyzed by ethnicity, the LTA A252G polymorphism significantly decreased sepsis risk in the Asian population for the recessive model [GG vs. GA+AA: OR = 0.82, 95%CI = 0.68–0.99, p = 0.04] but not in the Caucasian population. Moreover, comparisons between sepsis patients who survived and those who did not suggested that the LTA A252G polymorphism decreases the risk of mortality [GG+GA vs. AA: OR = 0.57, 95%CI = 0.41–0.80, p < 0.01].

Conclusion

Our results suggested that the A252G polymorphism in the LTA gene decreased the risk of sepsis in Asians and may reduce mortality in septic individuals.

MPPED2 Polymorphism Is Associated With Altered Systemic Inflammation and Adverse Trauma Outcomes

Trauma is a leading cause of morbidity and mortality. It is unclear why some trauma victims follow a complicated clinical course and die, while others, with apparently similar injury characteristics, do not. Interpatient genomic differences, in the form of single nucleotide polymorphisms (SNPs), have been associated previously with adverse outcomes after trauma. Recently, we identified seven novel SNPs associated with mortality following trauma. The aim of the present study was to determine if one or more of these SNPs was also associated with worse clinical outcomes and altered inflammatory trajectories in trauma survivors. Accordingly, of 413 trauma survivors, DNA samples, full blood samples, and clinical data were collected at multiple time points in the first 24 h and then daily over 7 days following hospital admission. Subsequently, single-SNP groups were created and outcomes, such as hospital length of stay (LOS), ICU LOS, and requirement for mechanical ventilation, were compared. Across a broad range of Injury Severity Scores (ISS), patients carrying the rs2065418 TT SNP in the metallophosphoesterase domain-containing 2 (MPPED2) gene exhibited higher Marshall MODScores vs. the control group of rs2065418 TG/GG patients. In patients with high-severity trauma (ISS ≥ 25, n = 94), those carrying the rs2065418 TT SNP in MPPED2 exhibited higher Marshall MODScores, longer hospital LOS (21.8 ± 2 days), a greater requirement for mechanical ventilation (9.2 ± 1.4 days on ventilator, DOV), and higher creatinine plasma levels over 7 days vs. the control group of rs2065418 TG/GG high-severity trauma patients (LOS: 15.9 ± 1.2 days, p = 0.03; DOV: 5.7 ± 1 days, p = 0.04; plasma creatinine; p < 0.0001 MODScore: p = 0.0003). Furthermore, rs2065418 TT patients with ISS ≥ 25 had significantly different plasma levels of nine circulating inflammatory mediators and elevated dynamic network complexity. These studies suggest that the rs2065418 TT genotype in the MPPED2 gene is associated with altered systemic inflammation, increased organ dysfunction, and greater hospital resource utilization. A screening for this specific SNP at admission might stratify severely injured patients regarding their lung and kidney function and clinical complications.

Maternal pro-inflammatory state during pregnancy and newborn leukocyte telomere length: A prospective investigation

INTRODUCTION

Telomere biology plays a fundamental role in maintaining the integrity of the genome and cell, and shortened telomeres have been linked to several age-related diseases. The initial (newborn) telomere length (TL) represents a critically important feature of the telomere biology system. Exposure to a variety of adverse prenatal conditions such as maternal stress, suboptimal diet, obesity, and obstetric complications, is associated with shorter offspring TL at birth and in adult life. Many, if not all, of these exposures are believed to have an inflammatory component. In this context, stress-related immunological processes during pregnancy may constitute a potential additional biological pathway because they can affect telomere length and telomerase activity via transcriptions factors such as cyclic adenosine monophosphate-dependent transcription factor (ATF7) and nuclear factor-kappa B (NF-κB). Thus, in the present study we examined the hypothesis that maternal pro-inflammatory state across pregnancy, operationalized as the balance between tumor necrosis factor (TNF)-α, a major pro-inflammatory cytokine, and interleukin-10 (IL-10), the major anti-inflammatory cytokine, is associated with newborn leukocyte telomere length (LTL) at birth.

METHODS AND MATERIALS

Participants were healthy women (N = 112) recruited in early pregnancy. Concentrations of TNF- α and IL-10 were quantified in early, mid and late pregnancy from maternal blood samples. Telomere length was assessed in newborn blood samples soon after birth.

RESULTS

After adjusting for maternal age, maternal pre-pregnancy BMI, birth weight percentile, and infant sex, a higher mean TNF-α/IL-10 ratio across pregnancy was significantly associated with shorter newborn TL (β = -.205, p = .030). Newborn TL was, on average, 10% shorter in offspring of women in the upper compared to lower quartile of the TNF-α/IL-10 ratio during pregnancy.

DISCUSSION

These findings provide new evidence in humans for a potential "programming" mechanism linking maternal systemic pro-inflammatory processes during pregnancy with the initial (newborn) setting of her offspring's telomere system.

Pathogenetic factors involved in recurrent pregnancy loss from multiple aspects

Recurrent pregnancy loss (RPL) is a common complication in obstetrics, affecting about 5% of women of childbearing age. An increase in the number of abortions results in escalation in the risk of miscarriage. Although concentrated research has identified numerous causes for RPL, about 50% of them remain unexplained. Pregnancy is a complex process, comprising fertilization, implantation, organ and tissue differentiation, and fetal growth, which is effectively controlled by a number of both maternal and fetal factors. An example is the immune response, in which T cells and natural killer cells participate, and inflammation mediated by tumor necrosis factor or colony-stimulating factor, which hinders embryo implantation. Furthermore, vitamin D affects glucose metabolism and inhibits embryonic development, whereas microRNA has a negative effect on the gene expression of embryo implantation and development. This review examines the causes of RPL from multiple perspectives, and focuses on the numerous factors that may result in RPL.

Tumor Necrosis Factor-α -308G/A Genetic Polymorphism and the Susceptibility of Posttraumatic Sepsis

Summary of background data

The association between tumor necrosis factor α (TNFα) -308G/A polymorphism and susceptibility to posttraumatic sepsis has been studied extensively. But the results have not remained very clear.

Purpose

We carried out this meta-analysis to explore the influence of TNF on susceptibility to posttraumatic sepsis.

Methods

Relevant studies were identified from PubMed, Web of Science, Embase, and China National Knowledge Internet without language limitation, following the inclusion and exclusion criteria. Statistical analyses were implemented with the STATA 12.0 statistical software.

Results

Seven case-control studies were included in the meta-analyses on the association of TNFα -308 G/A genetic polymorphism and risk of posttraumatic sepsis. TNFα -308 G/A genetic polymorphism was significantly associated with susceptibility to posttraumatic sepsis in the dominant model [odds ratio (OR), 2.17; 95% confidence interval (95% CI), 1.19–3.95; P = 0.011] and allelic model (OR, 1.72; 95% CI, 1.23–2.39; P = 0.001), but not in the heterozygous model (OR, 1.38; 95% CI, 0.58–3.39; P = 0.489). There was no significant publication bias for these 3 models. However, marked heterogeneity existed in the dominant model (I2 = 68.9%, P = 0.004) and the heterozygous model (I2 = 68.9%, P = 0.022).

Conclusions

TNF -308 G/A genetic polymorphism may have an influence on susceptibility to posttraumatic sepsis. Further studies with large sample sizes and well-designed studies are needed to confirm these results.

An Enrichment Strategy Yields Seven Novel Single Nucleotide Polymorphisms Associated With Mortality and Altered Th17 Responses Following Blunt Trauma

Trauma is the leading cause of death worldwide for individuals under the age of 55. Interpatient genomic differences, in the form of candidate single-nucleotide polymorphisms (SNPs), have been associated previously with adverse outcomes after trauma. However, the utility of these SNPs to predict outcomes based on a meaningful endpoint such as survival is as yet undefined. We hypothesized that specific SNP haplotypes could segregate trauma survivors from non-survivors. Genomic DNA samples were obtained from 453 blunt trauma patients, for whom complete daily clinical and biomarker data were available for 397. Of these, 13 patients were non-survivors and the remaining 384 were survivors. All 397 DNA samples were amplified, fragmented, and examined for 551,839 SNPs using the Illumina Infinium CoreExome-24 v1.1 BeadChip (Illumina). To enrich for likely important SNPs, we initially compared SNPs of the 13 non-survivors versus 13 matched survivors, who were matched algorithmically for injury severity score (ISS), age, and gender ratio. This initial enrichment yielded 126 SNPs; a further comparison to the haplotypes of the remaining 371 survivors yielded a final total of 7 SNPs that distinguished survivors from non-survivors. Furthermore, severely injured survivors with the same seven SNPs as non-survivor exhibited distinct inflammatory responses from similarly injured survivors without those SNPs, and specifically had evidence of altered Th17 cell phenotypes based on computational modeling. These studies suggest an interaction among genetic polymorphism, injury severity, and initial inflammatory responses in driving trauma outcomes.

Early Diagnosis of Sepsis: Is an Integrated Omics Approach the Way Forward?

Sepsis remains one of the leading causes of death in the USA and it is expected to get worse as the population ages. Moreover, the standard of care, which recommends aggressive treatment with appropriate antibiotics, has led to an increase in multiple drug-resistant organisms. There is a dire need for the development of new antibiotics, improved antibiotic stewardship, and therapies that treat the host response. Development of new sepsis therapeutics has been a disappointment as no drugs are currently approved to treat the various complications from sepsis. Much of the failure has been blamed on animal models that do not accurately reflect the course of the disease. However, recent improvements in metabolomic, transcriptomic, genomic, and proteomic platforms have allowed for a broad-spectrum look at molecular changes in the host response using clinical samples. Integration of these multi-omic datasets allows researchers to perform systems biology approaches to identify novel pathophysiology of the disease. In this review, we highlight what is currently known about sepsis and how integrative omics has identified new diagnostic and predictive models of sepsis as well as novel mechanisms. These changes may improve patient care as well as guide future preclinical analysis of sepsis.

Specific microRNA signatures responsible for immune disturbance related to hip fracture in aged rats

Background

Hip fracture is commonly associated with an overwhelming inflammatory response, which may lead to high rates of morbidity and mortality in the elderly. MicroRNAs (miRNAs) play important roles in the functions of immune system. However, the association between miRNA dysregulation and immune disturbance (IMD) related to elderly hip fracture is largely unknown.

Methods

In this study, microarray profiling was carried out to evaluate the differential expression patterns of miRNAs in plasma of the aged hip fracture rats with IMD, those without IMD, and normal aged rats, followed by validation using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Genes and signaling pathways of the dysregulated miRNAs related to elderly hip fracture-induced IMD were investigated in silico using Gene Ontology and analysis of Kyoto Encyclopedia of Genes or Genomes.

Results

Dead or moribund rats with hip fracture exhibited significantly reduced TNF-α/IL-10 ratio compared with healthy controls and other hip fracture rats, which were therefore named as hip fracture rats with IMD. Seven serum miRNAs in hip fracture rats with IMD were significantly downregulated. qRT-PCR and in silico analysis revealed that miR-130a-3p likely participated in regulating the hip fracture-induced IMD. Furthermore, Western blot experiment demonstrated that in lung tissue, the reduction of miR-130a-3p was accompanied with the increase of the protein expression of interferon regulatory factor-1 (IRF1) and sphingosine-1-phosphate receptor 1 (SIPR1).

Conclusions

miR-130a-3p desregulation may be associated with elderly hip fracture-induced IMD, which might act as a new potential biomarker for the diagnosis and prognosis of elderly hip fracture-induced IMD and a potential therapeutic target as well.

The effects of tumor necrosis factor-α (TNF-α) rs1800629 and rs361525 polymorphisms on sepsis risk

This meta-analysis of 23 eligible articles comprehensively and quantitatively evaluated the effects of tumor necrosis factor-α (TNF-α) rs1800629 and rs361525 polymorphisms on sepsis risk. We found that TNF-α rs1800629 was associated with increased sepsis risk in the overall population in four genetic models, including A vs. G (P<0.001, odds ratio (OR)=1.32), GA vs. GG (P<0.001, OR=1.46), GA+AA vs. GG (P<0.001, OR=1.46), and carrier A vs. carrier G (P<0.001, OR=1.32). Subgroup analyses showed a similar result for Asian patients (all P<0.05, OR>1). TNF-α rs361525 was also associated with increased sepsis risk in Asian patients in the four genetic models (all P<0.05, OR>1). Begg's and Egger's tests excluded large publication bias, and sensitivity analysis indicated stable results. Our results suggest that the G/A genotype of TNF-α rs1800629 and rs361525 increases sepsis risk in an Asian population.

Tumor necrosis factor-α -308 G/A polymorphism and risk of sepsis, septic shock, and mortality: an updated meta-analysis

Background

The -308G/A polymorphism in the gene encoding tumor necrosis factor-α (TNF-α) has been implicated in sepsis risk in many studies but with variable results. This study aimed to comprehensively assess the evidence of association between this polymorphism and risk of sepsis and sepsis-related mortality.

Materials and Methods

PubMed, EMBASE and other databases were searched to identify relevant studies, and data were analyzed using Review Manager 5.0 and STATA 12.0.

Results

Data from 34 publications involving 12,284 subjects were meta-analyzed. Combined analysis revealed an association between TNF-α -308G/A gene polymorphism and risk of sepsis (AA+GA vs. GG, OR 1.35, 95% CI 1.10–1.67, P = 0.005). This association was observed in the Caucasian subgroup (OR 1.50, 95% CI 1.13–2.00, P = 0.006), but not in the Asian subgroup. Across the entire study population, the polymorphism was also significantly related to septic shock risk (OR 1.52, 95% CI 1.18–1.95, P = 0.001) but not to sepsis-related mortality (OR 0.99, 95% CI 0.71–1.40, P = 0.97).

Conclusions

This meta-analysis suggests that the -308G/A gene polymorphism in the TNF-α gene may contribute to risk of sepsis and septic shock, but not risk of mortality.

Cytokines in systemic lupus erythematosus: far beyond Th1/Th2 dualism lupus: cytokine profiles

The aims of this study were to delineate cytokine profiles of systemic lupus erythematosus (SLE), construct prediction models for diagnosis and disease activity using those profiles, and to examine the associations between TNFB Ncol polymorphism, body mass index (BMI) and vitamin D levels with cytokine levels. Two hundred SLE patients and 196 healthy controls participated in this case-control study. Plasma cytokines levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-1β, IL- 4, IL-6, IL-10, IL-12 and IL-17 were measured and cytokines profiles were computed. IL-6, IL-12, IL-17, IFN-γ and IL-10 levels were significantly higher in SLE, while IL-4 was lower in SLE. The Th1/Th2 and Th1+Th17/Th2 profiles were significantly higher in SLE than in healthy controls, whereas there were no significant differences in the proinflammatory cytokine profile (TNFα+IL-6+IL-1β). In total, 90.4% of all subjects were correctly classified using Th1+Th17 profile and IL-10 (positively associated) and IL-4 (negatively associated) as predictor variables (sensitivity=66.7% and specificity=96.9%). In all, 20.9% of the variance in the SLE Disease Activity Index was predicted by the Th1+Th17/Th2 ratio, IL-10 and BMI (all positively) and proinflammatory profile (inversely associated). B1/B1 genotype is accompanied by increased IL-17 and Th17/Th2 ratio, while B1/B2 genotype is accompanied by higher IL-4 and IFNγ values. 25-OH vitamin D was inversely associated with IFN-γ levels. SLE is accompanied by Th1, Th17 and Treg profile and lowered IL-4 production. Lowered vitamin D levels and B1/B1 genotype, but not BMI, contribute to changes in cytokines profiles. Future treatments should target Th1, Th2 and Th17 profiles rather than inflammatory cytokines.

Genetic, Immune-Inflammatory, and Oxidative Stress Biomarkers as Predictors for Disability and Disease Progression in Multiple Sclerosis

The aim of this study was to evaluate the TNFβ NcoI polymorphism (rs909253) and immune-inflammatory, oxidative, and nitrosative stress (IO&NS) biomarkers as predictors of disease progression in multiple sclerosis (MS). We included 212 MS patients (150 female, 62 male, mean (±standard deviation (SD)) age = 42.7 ± 13.8 years) and 249 healthy controls (177 female, 72 male, 36.8 ± 11 years). The disability was measured the Expanded Disability Status Scale (EDSS) in 2006 and 2011. We determined the TNFβ NcoI polymorphism and serum levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, IL-4, IL-10, and IL-17, albumin, ferritin, and plasma levels of lipid hydroperoxides (CL-LOOH), carbonyl protein, advanced oxidation protein products (AOPPs), nitric oxide metabolites (NOx), and total radical-trapping antioxidant parameter (TRAP). The mean EDSS (±SD) in 2006 was 1.62 ± 2.01 and in 2011 3.16 ± 2.29, and disease duration was 7.34 ± 7.0 years. IL-10, TNF-α, IFN-γ, AOPP, and NOx levels were significantly higher and IL-4 lower in MS patients with a higher 2011 EDSS scores (≥3) as compared with those with EDSS < 3. The actual increases in EDSS from 2006 to 2011 were positively associated with TNF-α and IFN-γ. Increased IFN-γ values were associated with higher pyramidal symptoms and increased IL-6 with sensitive symptoms. Increased carbonyl protein and IL-10 but lowered albumin levels predicted cerebellar symptoms. The TNFB1/B2 genotype decreased risk towards progression of pyramidal symptoms. Treatments with IFN-β and glatiramer acetate significantly reduced TNF-α but did not affect the other IO&NS biomarkers or disease progression. Taken together, IO&NS biomarkers and NcoI TNFβ genotypes predict high disability in MS and are associated with different aspects of disease progression. New drugs to treat MS should also target oxidative stress pathways.

Evaluation of Tumor Necrosis Factor Alpha Polymorphism Frequencies in Endometriosis

BACKGROUND

The pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-α), is a pathogenic element for a number of disorders. Previous studies have reported that the -1031 T/C and -238 G/A polymorphisms in the promoter region of the TNF-α gene are important factors in reproductive-related disorders. One of the most common gynecological diseases of women during the reproductive years is endometriosis. This study aims to assess an association between the -1031 T/C, -238 G/A and -308 G/A polymorphisms of the TNF-α gene promoter region to endometriosis.

MATERIALS AND METHODS

In this case-control study, we enrolled 65 endometriosis patients and 65 matched healthy control women by simple sampling. Polymerase chain reaction (PCR) analysis was used to analyze -1031 T/C, -238 G/A and -308 G/A polymorphisms in the TNF-α gene promoter region. Statistical analysis was performed using the chi-square test. P values less than 0.05 were considered statistically significant.

RESULTS

We found a strong association between the -1031 T/C polymorphism in the promoter region of the TNF-α gene with endometriosis (P=0.001). There were no significant associations between the -238 G/A (P=0.243) and -308 G/A (P=1) polymorphisms with endometriosis and again endometriosis stages have no association with these polymorphisms.

CONCLUSION

The -1031 T/C polymorphism and CC genotype can be used as a relevant marker to identify women at risk of developing endometriosis.

TNF-α, IL-6, and IL-8 cytokines and their association with TNF-α-308 G/A polymorphism and postoperative sepsis

INTRODUCTION

Early prediction of postoperative sepsis remains an enormous clinical challenge. Association of TNF-α-308 G/A polymorphism with sepsis remains controversial. We, therefore, investigated this polymorphism with serum levels of cytokines TNF-α, IL-6, and IL-8 in relation to development of sepsis following major gastrointestinal surgery.

METHODS

Two hundred and thirty-nine patients undergoing major gastrointestinal surgery were enrolled. Polymorphism was studied through the analysis of restriction fragments of Nco1-digested DNA with the polymerase chain reaction. All patients were followed for 1 month following surgery for evidence of sepsis. Levels of serum cytokines TNF-α, IL-6, and IL-8 were measured preoperatively and postoperatively by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Forty-seven (19.66 %) patients developed postoperative sepsis. Patients with postoperative sepsis were significantly (p = 0.002) more likely to possess AA homozygous genotype with higher capacity to produce cytokines TNF-α (p < 0.0001), IL-6 (p < 0.0001), and IL-8 (p < 0.0001) as compared to other genotypes. When compared with patients carrying at least one G allele, the AA genotype was associated with a significantly higher probability (odds ratio (OR) = 4.17; p = 0.003; 95 % confidence interval (CI) = 1.5-11.48) of developing sepsis. Compared with the GG genotype, AA was associated with a significantly higher probability (OR = 5.18; p = 0.0008; 95 % CI = 1.82-14.76) of sepsis development.

CONCLUSION

TNF-α-308 G/A polymorphism is significantly associated with the development of postoperative sepsis and with increased expression of cytokines TNF-α, IL-6, and IL-8.

NF-κB-modulated miR-130a targets TNF-α in cervical cancer cells

Background

Nuclear factor-κB (NF-κB) induces a variety of biological processes through transcriptional gene control whose products are components in various signaling pathways. MicroRNAs are a small endogenous non-coding RNAs that regulate gene expression and are involved in tumorigenesis. Using human cervical cancer cell lines, this study aimed to investigate whether NF-κB could regulate miR-130a expression and the functions and targets of miR-130a.

Methods

We used the HeLa and C₃₃A cervical cancer cell lines that were transfected with NF-κB or miR-130a overexpression plasmids to evaluate their effects on cell growth. We utilized bioinformatics, a fluorescent reporter assay, qRT-PCR and Western blotting to identify downstream target genes.

Results

In HeLa and C₃₃A cells, NF-κB and miR-130a overexpression promoted cell growth, but genetic knockdowns suppressed growth. TNF-α was identified as a target of miR-130a by binding in a 3’-untranslated region (3’UTR) EGFP reporter assay and by Western blot analysis. Furthermore, low TNF-α concentrations stimulated NF-κB activity and then induced miR-130a expression, and TNF-α overexpression rescued the effects of miR-130a on cervical cancer cells.

Conclusions

Our findings indicate that TNF-α can activate NF-κB activity, which can reduce miR-130a expression, and that miR-130a targets and downregulates TNF-α expression. Hence, we shed light on the negative feedback regulation of NF-κB/miR-130a/TNF-α/NF-κB in cervical cancer and may provide insight into the carcinogenesis of cervical cancer.

The Value of Admission Serum IL-8 Monitoring and the Correlation with IL-8 (-251A/T) Polymorphism in Critically Ill Patients

Background. The clinical management of sepsis is a highly complicated process. Disruption of the immune system explains in part the major variation in sepsis outcome. IL-8 is a proinflammatory cytokine, genetic polymorphism of this cytokine could explain the outcome of sepsis. The present study was conducted to determine the value of serum IL-8 monitoring and its (-251A/T) genetic polymorphism in critically ill patients. Patients and Methods. 180 critically ill patients were allocated into two groups, 90 septic patients (sepsis group) and 90 nonseptic patients (SIRS group). Admission serum IL-8 and its (-251A/T) mutant allele were detected. Results. The admission mean value of serum IL-8 was significantly elevated in sepsis group. In both groups, the mean value of serum IL-8 in nonsurvived patients and patients with IL-8 (-251A/T) mutant allele was significantly higher. A positive correlation of survival and IL-8 (-251A/T) mutant allele was detected in both groups. The serum IL-8 distinguished wild from IL-8 (-251A/T) mutant allele at a cut-off value of 600 pg/mL. Conclusion. The admission mean value of serum IL-8 was significantly elevated in septic, nonsurvived, and patients with IL-8 (-251A/T) mutant alleles. A positive correlation of survival and IL-8 (-251A/T) mutant allele patients was detected.

A nonsynonymous polymorphism of IRAK4 associated with increased prevalence of gram-positive infection and decreased response to toll-like receptor ligands

Mutations in IRAK4 have been associated with recurrent Gram-positive infections in children. Given the central role of IRAK4 in innate immunity signaling, we hypothesized that common genetic variants of IRAK4 may be associated with prevalence of Gram-positive infection in critically ill adults. Haplotype clade tag single nucleotide polymorphisms (SNPs) of the IRAK4 gene were selected and genotyped in a cohort of 1,029 critically ill patients with systemic inflammatory response syndrome (SIRS). We found that a haplotype clade tagged by the A allele of the htSNP G29429A (Ala428Thr) was associated with increased relative risk of Gram-positive infection at admission to ICU (RR = 1.2, p < 0.05). Furthermore, the 29429A allele was associated with decreased lymphoblastoid cell response to CpG (as measured by IL-6 production) (raw values ± 95% CI 40.3 ± 32.3 vs. 85.8 ± 29.4 pg/ml; log-transformed values ± 95% CI 1.13 ± 0.37 vs. 1.55 ± 0.18, p < 0.04). We also found that IRAK4-deficient fibroblasts transfected with an IRAK4 expression plasmid containing the 29429A allele produced less IL-6 in response to lipopolysaccharide (p = 0.07). Our data suggest that the IRAK4 haplotype clade marked by 29429A (428Thr) alters susceptibility to Gram-positive bacteria, by decreasing cellular response to TLR ligands.

Association of tumor necrosis factor β genetic polymorphism and sepsis susceptibility

The association of the tumor necrosis factor β (TNF-β) Nco1 genetic polymorphism with susceptibility to sepsis was evaluated in 60 consecutive patients diagnosed with sepsis and in 148 healthy blood donors. Genomic DNA was extracted from peripheral blood cells and a 782 base-pair fragment of the TNF-β gene was amplified by PCR. The PCR products were subjected to Nco1 restriction digestion and analysed by restriction fragment length polymorphism analysis. Tumor necrosis factor α (TNF-α) and the C-reactive protein (CRP) serum levels were also determined by ELISA and nephelometry, respectively. Among the septic patients, the allelic frequencies of TNFB1 and TNFB2 were 0.2833 and 0.7166, respectively, and they differed from those observed in the blood donors (p=0.0282). The TNFB2 allele frequency was higher in the septic patients than in the blood donors [odds ratio=1.65 (CI 95% 1.02-2.69), p=0.0315]. The TNF-α and CRP serum levels and the APACHE II and SOFA clinical scores did not differ in the patients with the TNFB1 or TNFB2 alleles (p>0.05). The results suggest that the TNFB2 allele is associated with susceptibility to sepsis, but it was not found to be associated with the immunological and clinical biomarkers of the disease.

Ethical considerations in the collection of genetic data from critically ill patients: what do published studies reveal about potential directions for empirical ethics research?

Critical illness trials involving genetic data collection are increasingly commonplace and pose challenges not encountered in less acute settings, related in part to the precipitous, severe and incapacitating nature of the diseases involved. We performed a systematic literature review to understand the nature of such studies conducted to date, and to consider, from an ethical perspective, potential barriers to future investigations. We identified 79 trials enrolling 24 499 subjects. Median (interquartile range) number of participants per study was 263 (116.75-430.75). Of these individuals, 16 269 (66.4%) were Caucasian, 1327 (5.4%) were African American, 1707 (7.0%) were Asian Pacific Islanders and 139 (0.6%) were Latino. For 5020 participants (20.5%), ethnicity was not reported. Forty-eight studies (60.8%) recruited subjects from single centers and all studies examined a relatively small number of genetic markers. Technological advances have rendered it feasible to conduct clinical studies using high-density genome-wide scanning. It will be necessary for future critical illness trials using these approaches to be of greater scope and complexity than those so far reported. Empirical research into issues related to greater ethnic inclusivity, accuracy of substituted judgment and specimen stewardship may be essential for enabling the conduct of such trials.

The genetic predisposition to adverse outcome after trauma

Technological advances and shorter rescue times have allowed early and effective resuscitation after trauma and brought attention to the host response to injury. Trauma patients are at risk of progressive organ dysfunction from what appears to be an uncontrolled immune response. The availability of improved techniques of molecular diagnosis has allowed investigation of the role of genetic variations in the inflammatory response to post-traumatic complications and particularly to sepsis.

This review examines the current evidence for the genetic predisposition to adverse outcome after trauma. While there is evidence supporting the involvement of different polymorphic variants of genes in determining the post-traumatic course and the development of complications, larger-scale studies are needed to improve the understanding of how genetic variability influences the responses to post-traumatic complications and pharmacotherapy.

Functional significance of gene polymorphisms in the promoter of myeloid differentiation-2

OBJECTIVE

To investigate the functional significance of the reported single nucleotide polymorphisms (SNPs) in the promoter of the myeloid differentiation-2 (MD-2) gene.

SUMMARY BACKGROUND DATA

Functional gene polymorphisms of innate immune receptors have been shown to be critical determinants of the immune inflammatory response. MD-2 is an important signaling enhancer protein in the endotoxin (LPS) receptor complex. Although a total of 156 SNPs have been identified within the whole MD-2 gene, little is known about the functional significance of these SNPs.

METHODS

: The possible biosignificance of 8 reported SNPs was analyzed using on-line software tools. The selected SNPs were then genotyped using a restriction fragment length polymorphism method applied to 711 healthy Chinese volunteers. Their functional effects were assessed by the observation of transcription activity, MD-2 mRNA expression, and leukocyte response to ex vitro LPS stimulation. Moreover, the clinical relevance of these SNPs was investigated in 105 patients with major trauma.

RESULTS

Three SNPs (C-1625G, A-1064G, and A-475T) in the MD-2 promoter were selected based on bio-informatic analysis. Both -1625 and -1064 SNPs, rather than -475, were seen in the Chinese population, with frequencies of 19.8% (-1625G) and 34.7% (-1064G). But only the -1625 polymorphism was found to affect MD-2 promoter activity. Moreover, the expression of MD-2 mRNA and the production of TNF-alpha in whole blood leukocytes, in response to LPS stimulation, were significantly increased in subjects with the -1625 G allele. Patients who possessed the -1625 G allele were more likely to experience complications with organ dysfunction and sepsis after major trauma. All these associations were in allele-dose dependent effect.

CONCLUSIONS

The MD-2/-1625 polymorphism is an important functional variant.

TUMOUR NECROSIS FACTOR: IMPLICATIONS FOR SURGICAL PATIENTS

Tumour necrosis factor alpha (TNF-alpha) is an inflammatory cytokine primarily produced by macrophages. It is a unique protein with contradictive properties; it has the ability to induce cellular death by apoptosis and oncosis, but can also induce cellular regeneration and growth. Genetic polymorphisms in TNFA have been associated with poor outcome in some surgical patients and this may provide a useful tool to screen for high-risk patients. Manipulating TNF-alpha levels in vivo may influence the progression of several pathological conditions. TNF-alpha has anti-cancer properties and has been used to treat cancer patients. Treatment with anti-TNF-alpha drugs and antibodies has been successful in rheumatoid arthritis and other autoimmune diseases, but disappointing in the management of patients with sepsis. This review article focuses on the biological activities, genetic polymorphism of TNFA and the role of TNF-alpha and anti-TNF-alpha treatments, based on animal experiments and clinical trials.

Tumor necrosis factor-alpha -308G>A allelic variant modulates iron accumulation in patients with hereditary hemochromatosis

BACKGROUND

In vitro and animal studies suggest that tumor necrosis factor alpha (TNF-alpha) modulates intestinal iron transport. We hypothesized that the effect of TNF-alpha might be particularly relevant if iron absorption is not effectively controlled by the HFE gene.

METHODS

In patients with homozygous C282Y hemochromatosis, we investigated the influence of TNF-alpha -308G>A allelic variant on total body iron overload, determined in all patients by measuring iron removed during depletion therapy, and hepatic iron index and need for phlebotomy to prevent iron reaccumulation, measured in patient subgroups.

RESULTS

Of 86 patients with hereditary hemochromatosis, 16 (19%) were heterozygous carriers and 1 (1%) was a homozygous carrier of the TNF-alpha promoter -308A allele. Mean (SD) total body iron overload was increased 2-fold in TNF-alpha -308A allele carriers [10.9 (7.6) g] compared with homozygous carriers of the G allele [5.6 (5.0) g, P<0.001]. Hepatic iron index differed markedly between TNF-alpha -308A allele carriers [5.6 (3.5) micromol/g/year] and homozygous G allele carriers [3.1 (2.2) micromol/g/year, P=0.040, n=30]. After iron depletion, the need for phlebotomy to prevent iron reaccumulation (maintenance therapy) was substantially higher in TNF-alpha -308A allele carriers than in homozygous G allele carriers (P=0.014, n=73). We used multiple regression analyses to exclude possible confounding effects of sex, age, family screening, body-mass index, and meat or alcohol intake.

CONCLUSION

TNF-alpha -308G>A allelic variant modulates iron accumulation in patients with hereditary (homozygous C282Y) hemochromatosis, but the effect of the TNF-alpha -308A allele on clinical manifestations of hemochromatosis was less accentuated than expected from the increased iron load associated with this allele.

Alterations in leukocyte function following surgical trauma: differentiation of distinct reaction types and association with tumor necrosis factor gene polymorphisms

Endotoxin-stimulated blood cytokine responses have been widely used to describe compromised host defense mechanisms after trauma. We investigated whether blood cytokine production after endotoxin stimulation is able to define distinct trauma-induced alteration patterns and whether alteration patterns are associated with tumor necrosis factor (TNF) gene polymorphisms. In 48 patients undergoing joint replacement, the levels of TNF alpha (TNF-alpha), interleukin 6 (IL-6), and IL-8 production in blood after endotoxin stimulation were measured preoperatively on the day of surgery and 24 h thereafter. Patients were genotyped for the TNF-alpha position -308 G/A polymorphism and the TNF-beta NcoI polymorphism. Postoperative alterations, i.e., increases or decreases of cytokine levels (TNF-alpha versus IL-6, P = 0.013; TNF-alpha versus IL-8, P = 0.001; IL-6 versus IL-8, P = 0.007), and relative postoperative changes, i.e., percentages of preoperative cytokine levels (TNF-alpha versus IL-6, r(s) = 0.491, P < 0.001; TNF-alpha versus IL-8, r(s) = 0.591, P < 0.001; IL-6 versus IL-8, r(s) = 0.474, P < 0.001 [where r(s) is the Spearman rank correlation coefficient]), had significant positive correlations among the cytokines. Overall enhanced postoperative alteration patterns were found in 10 patients, attenuated patterns were found in 18 patients, and mixed patterns were found in 20 patients. Preoperative cytokine production levels differed significantly between these groups (those of the overall enhanced pattern group were less than those of the mixed pattern group, which were less than those of the overall attenuated pattern group). TNF polymorphisms were not associated with overall alteration patterns, but the A*TNFB1 haplotype was associated with a postoperative increase in TNF-alpha production (P = 0.042). Whole-blood cytokine responses to endotoxin define the following preexisting patterns in leukocyte function: low baseline production and overall enhanced alteration patterns after trauma (type 1), intermediate baseline production and mixed alteration patterns (type 2), and high baseline production and overall attenuated alteration patterns (type 3). TNF gene polymorphisms were associated with changes in TNF-alpha production but do not explain the overall reaction patterns of cytokine production after trauma. The clinical correlate of these newly defined reaction types remains to be determined.

[Gene polymorphism in intensive care patients. Is the course of disease predetermined?]

Molecular biology has revolutionized medicine by increasing our understanding of the pathophysiological mechanisms of disease and the ability to assess genetic risk. Individual differences in disease manifestation and course in intensive care medicine often cannot be explained by known phenotypic risk factors alone. Recent data suggest an association between specific genotypes and the risk of adverse clinical outcomes. This includes inflammatory responses (i.e. TNF-alpha, Il-10), infectious diseases such as pneumonia or meningitis, sepsis, ARDS, as well as the mortality of critically injured patients (polytrauma, severe brain trauma). Continued identification of such allotypes and haplotypes may not only provide insight as to why the response to treatment varies amongst individuals in the intensive care unit, but also may potentially decrease morbidity and mortality through improved risk assessment and the administration of prophylactic therapy.