Polymorphism of tumor necrosis factor alpha (TNF-alpha) gene promoter, circulating TNF-alpha level, and cardiovascular risk factor for ischemic stroke

The effects of immunomodulatory drugs on cerebral small vessel disease: A mediation Mendelian randomization analysis

BACKGROUND

There are only a few recognized drug targets for cerebral small vessel disease (CSVD). Though inflammation is increasingly implicated in the development of CSVD, it remains unclear whether immunomodulation could become a therapeutic target. Accordingly, the Mendelian randomization (MR) method was used to assess the genetically proxied impacts of IL6 receptor (IL6R) inhibitor, IL1β inhibitor, Tumor necrosis factor (TNF) inhibitor and β-tubulin inhibitor on CSVD through.

METHODS

Single nucleotide polymorphisms (SNPs) near the IL6R, IL1β, TNFRSF1A and β-tubulin genes were identified as genetic proxies for immunomodulatory drugs. These SNPs exhibited significant associations with serum C-reactive protein (CRP) levels in a large European genome-wide association study. The causal effects of immunomodulatory drugs on CSVD manifestations and the mediation influence of 731 peripheral blood immune phenotypes linking these drugs to CSVD manifestations were examined using a two-sample two-step MR approach.

RESULTS

A total of 9, 18, 4 and 1 SNP were identified to proxy the effects of IL1β inhibitor, IL6R inhibitor, TNF inhibitor and β-tubulin inhibitor, respectively. MR analysis showed a significant causal relationship between IL1β inhibition and reduced volume of periventricular white matter hyperintensity (PWMH). IL6R inhibition was associated with a reduced risk of small vessel stroke, decreased axial diffusivity and mean diffusivity. Genetically proxied TNF inhibition may decrease the occurrence of cerebral microbleeds (CMBs) and severe enlarged perivascular spaces located at white matter (WM-EPVS). It could also protect WM integrity, as evidenced by the reduced volumes of PWMH and deep white matter hyperintensity (DWMH). Various peripheral blood immune phenotypes exhibited significant associations with immunomodulatory drugs. Notably, the median fluorescence intensity (MFI) of CD45 on CD8br cells partially mediated the effects of IL1β inhibitor on PWMH volume. Indirect effects of TNF inhibition on PWMH and DWMH volume through the MFI of CD127 on CD28- CD8br cells were observed. The effects of TNF inhibition on the occurrence of any CMBs were partially mediated by the MFI of CD45 on natural killer T cells, and the effects of TNF inhibition on the occurrence of lobar CMBs were partially mediated by the MFI of HLA DR on CD33- HLA DR+ cells. Furthermore, the MFI of HLA DR on CD33- HLA DR+ cells partially mediated the effects of TNF inhibition on WM-EPVS.

CONCLUSIONS

IL1β inhibitor, IL6R inhibitor and TNF inhibitor were associated with lower burden of CSVD while the activation of certain immune cells such as Tregs and myeloid cells partially mediated their protective effects.

Microglial Inflammatory Mechanisms in Stroke: The Jury Is Still Out

Microglia represent the main immune cell population in the CNS with unique homeostatic roles and contribution to broad neurological conditions. Stroke is associated with marked changes in microglial phenotypes and induction of inflammatory responses, which emerge as key modulators of brain injury, neurological outcome and regeneration. However, due to the limited availability of functional studies with selective targeting of microglia and microglia-related inflammatory pathways in stroke, the vast majority of observations remain correlative and controversial. Because extensive review articles discussing the role of inflammatory mechanisms in different forms of acute brain injury are available, here we focus on some specific pathways that appear to be important for stroke pathophysiology with assumed contribution by microglia. While the growing toolkit for microglia manipulation increasingly allows targeting inflammatory pathways in a cell-specific manner, reconsideration of some effects devoted to microglia may also be required. This may particularly concern the interpretation of inflammatory mechanisms that emerge in response to stroke as a form of sterile injury and change markedly in chronic inflammation and common stroke comorbidities.

Dihydroergotamine protects against ischemic stroke by modulating microglial/macrophage polarization and inhibiting inflammation in mice

OBJECTIVES

The search for drugs that can protect the brain tissue and reduce nerve damage in acute ischemic stroke has emerged as a research hotspot. We investigated the potential protective effects and mechanisms of action of dihydroergotamine against ischemic stroke.

METHODS

C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO), and dihydroergotamine at a dose of 10 mg/kg/day was intraperitoneally injected for 14 days. Adhesive removal and beam walking tests were conducted 1, 3, 5, 7, 10, and 14 days after MCAO surgery. Thereafter, the mechanism by which dihydroergotamine regulates microglia/macrophage polarization and inflammation and imparts ischemic stroke protection was studied using enzyme-linked immunosorbent assay, immunofluorescence staining, and western blotting.

RESULTS

From the perspective of a drug repurposing strategy, dihydroergotamine was found to inhibit oxygen-glucose deprivation damage to neurons, significantly improve cell survival rate, and likely exert a protective effect on ischemic brain injury. Dihydroergotamine significantly improved neural function scores and survival rates and reduced brain injury severity in mice. Furthermore, dihydroergotamine manifests its protective effect on ischemic brain injury by reducing the expression of TNF-α and IL-1β in mouse ischemic brain tissue, inhibiting the polarization of microglia/macrophage toward the M1 phenotype and promoting polarization toward the M2 phenotype.

CONCLUSION

This study is the first to demonstrate the protective effect of dihydroergotamine, a first-line treatment for migraine, against ischemic nerve injury in vitro and in vivo.

Association of IL-6 rs1800795, but not TNF-α rs1800629, and IL-1β rs16944 polymorphisms' genotypes with recovery of ischemic stroke patients following thrombolysis

OBJECTIVES

Inflammatory cytokines like tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 can cause brain injury, slow recovery, and adverse effects (ADEs) in ischemic stroke (IS) patients treated with recombinant tissue plasminogen activator (rtPA). We explored the relationship between selected polymorphisms within TNF-α, IL-1β and IL-6 genes, and post-IS outcome and ADEs in patients treated with rtPA.

METHODS

One hundred and sixty-six patients with IS treated with rtPA were included in this study. The modified Rankin Scale (mRS) was used to assess functional recovery 3 months after IS likewise thrombolytic therapy efficacy. Patients were classified into groups with favorable (0-1) or poor recovery based on their mRS score at the ninetieth day post-IS. During hospitalization, ADEs following rtPA were monitored. TNF-α-308 G/A (rs1800629), IL-1β-511 G/A (rs16944), and IL-6-174 G/C (rs1800795) polymorphisms were genotyped using Real-Time PCR. SPSS software version 22.0 was used for statistical analyses.

RESULTS

Patients with the TNF-α-308 G/A GG genotype had a higher mean NIHSS value at admission (12.75 ± 5.176) than those carrying A-allele (10.56 ± 3.979;p = 0.016). Individuals with the CC genotype of the IL-6-174 G/C polymorphism had significantly lower NIHSS scores (8.79 ± 5.053) than those with G-allele (12.06 ± 6.562) 24 hours after rtPA (p = 0.050). Patients with the GG genotype of the IL-6-174 G/C polymorphism had a significantly poorer outcome (p = 0.024; OR = 2.339; 95%CI 1.121-4.880), while patients who were G-allele carriers of the Il-6-174 G/C polymorphism and had the AA genotype of the IL-1β-511 G/A polymorphism were statistically significantly more likely to experience hemorrhagic transformation (p = 0.046; OR = 2.7273; 95%CI 1.0414-7.1426).

CONCLUSION

GG genotype of the IL-6-174 G/C polymorphism is associated with poor recovery after IS treated with rtPA therapy.

Tumor Necrosis Factor Alpha (TNFα) Gene Promoter Polymorphisms and Haplotypes are Associated with the Febrile Seizure (FS) and TNFα Serum Levels

Objectives

Febrile seizure (FS) is a neuroinflammatory disease involving fever-induced seizures affecting children in the early stages of life. TNFα is a pro-inflammatory cytokine reported to be elevated in FS. Specific promoter variants of TNFα could be associated with its elevated cytokine expression and susceptibility to FS. The present study analyzed the association of specific TNFα variants, including TNFα -238 G/A (rs361525), TNFα -308 G/A (rs1800629), and TNFα -376 G/A (rs1800750) promoter polymorphisms, with FS susceptibility, and TNFα serum levels in an Iranian population.

Materials & Methods

Sixty-eight FS patients and 136 controls were enrolled. The SSP-PCR method was utilized to analyze TNFα promoter genotypes. This research also confirmed the genotyping results by sequencing samples of ten patients and normal controls.

Results

The GG genotype of -238 SNP was associated with the increased risk of FS [OR = 12.65, 95% CI (2.83-56.60), P-value = 0.0012]. The AA genotype in the-308 region was increased in patients with FS and associated with the disease [OR = 4.62, 95% CI (1.46-14.56), P-value = 0.028]. The increased occurrence of heterozygous AG in the -376 SNP among control groups has been linked to a decreased risk of FS [OR = 0.22, 95% CI (0.11-0.43), P-value = 0.0001]. This study revealed that AGA (-238/ -308/ -376) haplotype with the highest frequency in controls was associated with a decreased risk of FS, while GAA (-238/ -308/ -376) carriers were more susceptible to FS.

Conclusion

The current study suggested that TNFα gene promoter variants at rs361525, rs1800629, and rs1800750 could be associated with the susceptibility to FS and altered serum levels of TNFα.

An ultrasensitive photoelectrochemical assay for tumor necrosis factor-alpha based on hollow CdS cubes as a signal generator and NiCo2O4-Au as a signal extinguisher

Sensitive detection of tumor necrosis factor-alpha (TNF-α) in human serum is beneficial for finding cancer patients early due to overexpressed TNF-α being related to some cancers. Here, a photoelectrochemical (PEC) aptasensor was constructed for ultrasensitive TNF-α assay based on the signal generator of hollow CdS cubes (H-CdS) and the signal extinguishing activity of NiCo2O4-Au. In this work, compared with traditional solid CdS, H-CdS could greatly promote the PEC signal because its hollow structure could accelerate the separation of photogenerated charges, which also possesses abundant active sites and high light absorption capability. Moreover, H-CdS can be prepared facilely with Cd-based Prussian blue analogs as the precursor. Meanwhile, NiCo2O4-Au was fabricated and utilized as a signal extinguisher. In the presence of TNF-α, NiCo2O4-Au could be introduced onto the H-CdS modified electrode, producing competitive consumption of the electron donor effect, the p-n semiconductor quenching effect, and the mimetic enzymatic catalytic precipitation effect, which all can significantly reduce the PEC signal. Based on the signal extinguishing activity of NiCo2O4-Au and the signal generator of H-CdS, TNF-α can be detected sensitively with a lower detection limit (0.63 fg mL-1) and a wide linear range (1 fg mL-1- to 1 ng mL-1), which may have a potential application in the PEC bioanalysis field and the disease diagnostics field.

Circulating Inflammatory Cytokine Associated with Poor Prognosis in Moyamoya Disease: A Prospective Cohort Study

Inflammation is a key factor in the development of moyamoya disease. However, the cytokine distribution in moyamoya disease and its impact on prognosis remain unclear. A total of 204 patients with moyamoya disease were enrolled in this study. The peripheral blood was analyzed for baseline data and cytokines, which included IL-6, IL-1β, IL-2R, IL-8, and TNF-α. Patients with the RNF213 mutation and those without the mutation were compared in terms of their differences in cytokines. A mRS score ≥2 was defined as a poor prognosis, and a mRS score <2 was described as a good prognosis, and differences in cytokines were compared between the two groups. Regression analysis was performed to identify markers affecting prognosis. TNF-α and IL-6 levels were higher in the group without the RNF213 mutation compared to the mutation group. Multivariate stepwise regression analysis indicated that the G3 subgroup of IL-6 and the G4 subgroup of TNF-α were the independent risk factors for adverse prognosis in adults with moyamoya disease (OR 3.678, 95% CI [1.491, 9.074], p = 0.005; OR 2.996, 95% CI [1.180, 7.610], p = 0.021). IL-6 and TNF-α were associated with poor prognosis in adult patients with moyamoya disease.

Clinical implications of PON1 (rs662) and TNF-α (rs1799964) genes polymorphism in patients with coronary artery disease

Background

Coronary artery disease (CAD) is the most common kind of heart problem, currently became one of the leading causes of death worldwide and is predicted to persist so for the next 20 years. The global risk factors to CAD include atherosclerosis, genetic predisposition, environment and the lifestyle. This study is aimed to find out the genotypic association of PON1 (rs662) and TNF-α (rs1799964) genes with CAD among North Indian populations. A total of 330 subjects including 175 CAD cases and 155 healthy controls were enrolled in this study. Single nucleotide polymorphisms were analyzed by polymerase chain reaction and restriction fragment length polymorphism (PCR–RFLP) method. χ2 and Student's t-tests were applied for the comparison of alleles and genotype frequencies in cases and controls. Logistic regression analysis was applied to calculate the 95% confidence intervals and odds ratios (OR) for assessing the association of genotype with disease.

Results

The PON1 gene QQ, QR, RR genotypes frequencies were 36.57%, 50.29%, 13.14% in CAD cases and 60%, 38.71%, 1.29% in controls, respectively. OR for the genotype QQ, QR, RR was 0.38, 1.6, 11.57 (P < 0.001, P = 0.035, P < 0.001). The TNF-α gene CC, CT, TT genotypes frequencies in cases were 4.57%, 50.29%, 45.14% and controls 3.23%, 46.45%, 50.32%, respectively. OR for CC, CT, TT genotype was 1.437, 1.166, 0.812 (P = 0.531, P = 0.487, P = 0.347). We found significant difference in the genotype and allele frequencies of PON1 gene between cases and control, while no significant difference was observed in TNF-α gene between cases and control.

Conclusions

The PON1 (rs662) gene polymorphisms were significantly associated with an elevated risk of CAD, while no significant association was observed with TNF-α (rs1799964) gene polymorphism and the risk of CAD.

Differential Regulation of the Immune System in Peripheral Blood Following Ischemic Stroke

Method

108 IS samples and 47 matched controls were obtained from the GEO database. Immune-related genes (IRGs) and their associated drugs were collected from the ImmPort and PharmGBK databases, respectively. Random forest (RF) regression and least absolute shrinkage and selection operator (LASSO) logistic regression were applied to identify immune-related genetic biomarkers (IRGBs) of IS, and accuracy was verified using neural network models. Finally, proportion changes of various immune cells in peripheral blood of IS patients were evaluated using CIBERSORT and xCell and correlation analyses were performed between IRGBs and differentially distributed immune cells.

Results

A total of 537 genes were differentially expressed between IS and control samples. Four immune-related differential expressed genes identified by regression analysis presented strong predictive power (AUC = 0.909) which we suggeseted them as immune-related genetic biomarkers (IRGBs). We also demonstrated six immune-related genes targeted by known drugs. In addition, post-IS immune system presented an increase in the proportion of innate immune cells and a decrease in adaptive immune cells in the peripheral circulation, and IRGBs showing significance were associated with this process.

Conclusion

The study identified CARD11, ICAM2, VIM, and CD19 as immune-related genetic biomarkers of IS. Six immune-related DEGs targeted by known drugs were found and provide new candidate drug targets for modulating the post-IS immune system. The innate immune cells and adaptive immune cells are diversified in the post-IS immune system, and IRGBs might play important role during this process.

TNF-α (G-308A) Polymorphism, Circulating Levels of TNF-α and IGF-1: Risk Factors for Ischemic Stroke—An Updated Meta-Analysis

Objective

Accumulated studies have explored gene polymorphisms and circulating levels of tumor necrosis factor (TNF)-α and insulin-like growth factor (IGF)-1 in the etiology of ischemic stroke (IS). Of the numerous etiopathological factors for IS, a single-nucleotide polymorphism (SNP) rs1800629 located in the TNF-α gene promoter region and increased levels of TNF-α were found to be associated with IS in different ethnic backgrounds. However, the published results are inconsistent and inconclusive. The primary objective of this meta-analysis was to investigate the concordance between rs1800629 polymorphism and IS. A secondary aim was to explore circulating levels of TNF-α and IGF-1 with IS in different ethnic backgrounds and different sourced specimens.

Methods

In this study, we examined whether rs1800629 genetic variant and levels of TNF-α and IGF-1 were related to the etiology of IS by performing a meta-analysis. Relevant case-control studies were retrieved by database searching and systematically selected according to established inclusion criteria.

Results

A total of 47 articles were identified that explored the relationship between the rs1800629 polymorphism and levels of TNF-α and IGF-1 with IS risk susceptibility. Statistical analyses revealed a significant association between the rs1800629 polymorphism and levels of TNF-α and IGF-1 with IS pathogenesis.

Conclusion

Our findings demonstrated that the TNF-α rs1800629 polymorphism, the increased levels of TNF-α, and decreased levels of IGF-1 were involved in the etiology of IS.

Disorder Genes Regulate the Progression of Ischemic Stroke through the NF-κB Signaling Pathway

Stroke is an acute cerebrovascular disease, including ischemic and hemorrhagic stroke. Stroke is the second leading cause of death after ischemic heart disease, which accounts for 9% of the global death toll. To explore the molecular mechanisms of the effects of the dysregulated factors, in the GEO database, we obtained transcriptome data from 24 h/72 h of mice with ischemic stroke and 24 h/72 h of normal mice. We then performed differential gene analysis, coexpression analysis, enrichment analysis, and regulator prediction bioinformatics analysis to identify the potential genes. We made a comparison between the ischemic stroke 72 h and the ischemic stroke for 24 h, and 5103 differential genes were obtained (p < 0.05). Four functional barrier modules were obtained by weighted gene coexpression network analysis. The critical genes of each module were ASTL, Zfp472, Fmr1 gene, and Nap1l1. The results of the enrichment analysis showed ncRNA metabolism, microRNAs in cancer, and biosynthesis of amino acids. These three functions and pathways have the most considerable count value. The regulators of the regulatory dysfunction module were predicted by pivotal analysis of TF and noncoding RNA, and critical regulators including NFKB1 (NF-κB1), NFKBIA, CTNNB1, and SP1 were obtained. Finally, the pivotal target gene found that CTNNB1, NFKB1, NFKBia, and Sp1 are involved in 18, 32, 2, and 60 target genes, respectively. Therefore, we believe that NFKB1 and Sp1 have a potential role in the progression of ischemic stroke. The NFKB signaling pathway promotes inflammatory cytokines and regulates the progression of ischemic stroke.

Promoter polymorphism of TNF-α (rs1800629) is associated with ischemic stroke susceptibility in a southern Thai population

Stroke represents the leading cause of disability and mortality amongst the elderly worldwide. Multiple risk factors, including both genetic and non-genetic components, as well as their interactions, are proposed as etiological factors involved in the development of ischemic stroke (IS). Promoter polymorphisms of the IL-6-174G/C (rs1800795) and TNF-α-308G/A (rs1800629) genes have been considered as predictive risk factors of IS; however, these have not yet been evaluated in a Thai population. The aims of this study were to investigate the association of IL-6-174G/C and TNF-α-308G/A polymorphisms with IS. Genomic DNA from 200 patients with IS and 200 controls were genotyped for IL-6-174G/C and TNF-α-308G/A polymorphisms using TaqMan™ SNP genotyping and quantitative PCR-high resolution melting analysis, respectively. It was found that the TNF-α-308 A allele was significantly associated with an increased risk of IS development compared with the G allele [odds ratio (OR)=2.044; 95% CI=1.154-3.620; P=0.014]. Moreover, the IS risk was significantly higher in the presence of TNF-α-308 GA or AA genotypes compared with that in the presence of GG genotypes with a dominant inheritance (OR=1.971; 95% CI=1.080-3.599; P=0.027). However, there was no association between IL-6-174G/C and the risk of IS development. The interaction study demonstrated that IL-6-174 GG and TNF-α-308 GG genotypes enhanced IS susceptibility when combined with hypertension, hyperlipidemia and alcohol consumption. Hypertensive and hyperlipidemic subjects with the TNF-α-308 GA and AA genotypes were more likely to develop IS compared with those who did not have these two conditions and had the GG genotype. In a matched study design (1:1), the IL-6-174 GC genotype was associated with higher IL-6 levels in the control group. Collectively, the present results highlight the utility of the TNF-α-308G/A polymorphism as a predictive genetic risk factor for development of IS.

Increased serum interleukin-34 levels as a novel diagnostic and prognostic biomarker in patients with acute ischemic stroke

BACKGROUND

Recent data reveal that interleukin-34 (IL-34) can drive inflammatory response, thereby participating in the pathogenesis of inflammatory diseases. However, the potential effect of IL-34 in acute ischemic stroke (AIS) remains unknown. The purpose of this study was to explore whether the levels of serum IL-34 were correlated with clinical severity or prognosis in AIS patients.

METHODS

In this prospective cohort study, serum IL-34 levels were detected in 150 healthy controls and 155 AIS patients. Univariate and multivariate logistic regression analysis were conducted to investigate the effect of IL-34 on the diagnosis and prognosis of AIS. ROC curve was utilized to evaluate predictive values for IL-34.

RESULTS

Serum IL-34 levels at admission were significantly higher in AIS patients than those in the healthy controls. Univariate and multivariate logistics regression analysis showed that IL-34 was an independent predictor of occurrence and functional outcome of AIS. The ROC curve demonstrated that IL-34 had a good predictive effect on the diagnosis and prognosis of AIS.

CONCLUSIONS

IL-34 can be used as a novel and independent diagnostic and predicting prognostic biomarker in AIS.

Bone Marrow Soluble Mediator Signatures of Patients With Philadelphia Chromosome-Negative Myeloproliferative Neoplasms

Background

Essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) are clonal hematological diseases classified as Philadelphia chromosome-negative myeloproliferative neoplasms (MPN). MPN pathogenesis is associated with the presence of somatic driver mutations, bone marrow (BM) niche alterations, and tumor inflammatory status. The relevance of soluble mediators in the pathogenesis of MPN led us to analyze the levels of cytokines, chemokines, and growth factors related to inflammation, angiogenesis and hematopoiesis regulation in the BM niche of MPN patients.

Methods

Soluble mediator levels in BM plasma samples from 17 healthy subjects, 28 ET, 19 PV, and 16 PMF patients were determined using a multiplex assay. Soluble mediator signatures were created from categorical analyses of high mediator producers. Soluble mediator connections and the correlation between plasma levels and clinic-laboratory parameters were also analyzed.

Results

The soluble mediator signatures of the BM niche of PV patients revealed a highly inflammatory and pro-angiogenic milieu, with increased levels of chemokines (CCL2, CCL5, CXCL8, CXCL12, CXCL10), and growth factors (GM-CSF M-CSF, HGF, IFN-γ, IL-1β, IL-6Ra, IL-12, IL-17, IL-18, TNF-α, VEGF, and VEGF-R2). ET and PMF patients presented intermediate inflammatory and pro-angiogenic profiles. Deregulation of soluble mediators was associated with some clinic-laboratory parameters of MPN patients, including vascular events, treatment status, risk stratification of disease, hemoglobin concentration, hematocrit, and red blood cell count.

Conclusions

Each MPN subtype exhibits a distinct soluble mediator signature. Deregulated production of BM soluble mediators may contribute to MPN pathogenesis and BM niche modification, provides pro-tumor stimuli, and is a potential target for future therapies.

Genetic variations in the human immune system influence susceptibility to tegumentary leishmaniasis: a systematic review and meta-analysis

OBJECTIVES

The outcomes of tegumentary leishmaniasis (TL) rely on a complex interaction between the host immune system and the parasite. This study assessed the influence of polymorphisms in immune-related genes on TL.

METHODS

Web of Science, Scopus, PubMed, and Embase databases were searched systemically. The meta-analysis used a retrospective model in examining alleles, heterozygotes, and homozygotes. A quality assessment and an analysis of cumulative evidence were performed.

RESULTS

A total of 29 genes (encoding for cytokines, chemokines, and other immune receptors) and 84 polymorphisms were analyzed. The IL-1β_rs16944 (OR = 1.341, p = 0.003), TNF-α_rs1800629 (OR = 3.804, p = 0.004), MIF_rs755622 (OR = 3.357, p = 0.001), and INF- γ_rs243056 (OR = 1.670, p = 0.028) polymorphisms were speculated as risk factor for TL. They decrease the expression of the corresponding genes crucial for TL control. The quality assessment score was approximately 50%, suggesting the need for a clear method and polymorphism characterization for further comparison. The relevant risk of bias and other considerations resulted in low and moderate cumulative evidence confidence.

CONCLUSIONS

IL-1β_rs16944, TNF-α_rs1800629, MIF_rs755622, and INF-γ_rs2430561 polymorphisms were speculated as risk factor for TL, corroborating that IL-1β, TNF-α, INF-γ, and MIF are involved in the TL pathogenesis.

Leukocyte TNFR1 and TNFR2 Expression Contributes to the Peripheral Immune Response in Cases with Ischemic Stroke

Tumor necrosis factor receptor 1 and 2 (TNFR1 and TNFR2) have been found in brain parenchyma of stroke patients, and plasma levels are increased in the acute phase of stroke. We evaluated associations between TNFR1 and TNFR2 plasma levels and stroke severity, infarct size, and functional outcome. Furthermore, we examined cellular expression of TNFR1 and TNFR2 on leukocyte subpopulations to explore the origin of the increased receptor levels. Blood samples were taken from 33 acute ischemic stroke patients and 10 healthy controls. TNFR1 and TNFR2 plasma concentrations were measured and correlated against the Scandinavian Stroke Scale at admission, infarct volume, and the modified Rankin Scale score three months after stroke onset. Classical, intermediate, and non-classical monocytes as well as neutrophils were purified, and cellular expression of TNFR1 and TNFR2 was examined using flow cytometry. TNFR1 and TNFR2 plasma levels were both increased after ischemic stroke, but we found no correlation with patient outcome measurements. Compared to healthy controls, ischemic stroke patients had decreased non-classical monocyte and neutrophil populations expressing TNFR1 and increased neutrophils expressing TNFR2, and decreased non-classical populations co-expressing both TNFR1 and TNFR2. This study supports the hypothesis of an acute immunological response orchestrated by the peripheral immune system following an ischemic stroke. However, the origin of the increased TNFR1 and TNFR2 plasma levels could not be clearly linked to peripheral monocytes or neutrophils. Future studies are needed and will help clarify the potential role as treatment target.

Investigating the mechanisms of Modified Xiaoyaosan (tiaogan-liqi prescription) in suppressing the progression of atherosclerosis, by means of integrative pharmacology and experimental validation

Atherosclerosis (AS)-related diseases remain among the leading causes of death worldwide. Modified Xiaoyaosan (also called Tiaogan-Liqi prescription, TGLQ), a traditional Chinese medical formulation, has been widely applied in the treatment of AS-related diseases. The aim of this study was to investigate the underlying pharmacological mechanisms of TGLQ in acting on AS. A total of 548 chemical compounds contained in TGLQ, and 969 putative targets, were collected from the Computation Platform for Integrative Pharmacology of Traditional Chinese Medicine, while 1005 therapeutic targets for the treatment of AS were obtained from the DisGeNET, TTD and CTD databases. Moreover, the 63 key targets were screened by the intersection of the targets above, and by network topological analysis. Further functional enrichment analysis showed that the key targets were significantly associated with regulation of the immune system and inflammation, improvement of lipid and glucose metabolism, regulation of the neuroendocrine system and anti-thrombosis effect. The in vivo experiments confirmed that TGLQ could reduce plasma lipid profiles and plasma inflammatory cytokines, and also inhibit AS plaque formation, within the AS model ApoE-/- mice. The in vitro experiments validated the hypothesis that TGLQ could significantly reduce intracellular lipid accumulation, suppress the production of inflammatory cytokines of macrophages induced by oxidized-LDL, and inhibit the protein expression of heat shock protein 90 and toll-like receptor 4. This study identified a list of key targets of TGLQ in the treatment of AS by applying an integrative pharmacology approach, which was validated by in vivo and in vitro experimentation.

[Clustering of diagnostic MRI signs of cerebral microangiopathy and its relationship with markers of inflammation and angiogenesis]

OBJECTIVE

To perform cluster analysis of MRI signs of cerebral microangiopathy (small vessel disease, SVD) and to clarify the relationship between the isolated groups and circulating markers of inflammation and angiogenesis.

MATERIAL AND METHODS

The identification of groups of MRI signs (MRI types) using cluster hierarchical agglomerative analysis and iterative algorithm of k-means and assessment of their relationship with serum concentrations of tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor-A (VEGF-A), hypoxia-inducible factor 1-α (HIF1-α) determined by ELISA were performed in 96 patients with SVD (STRIVE, 2013) (65 women, average age 60.91±6.57 years).

RESULTS

Cluster analysis of MRI signs identified two MRI types of SVD with Fazekas grade 3 of white matter hyperintensity (WMH). MRI type 1 (n=18; 6 women, mean age 59.1±6.8 years) and MRI type 2 (n=22, 15 f., mean age 63.5±6.2 years) did not differ by age, sex, severity of hypertension, presence of other risk factors. MRI type 1 had a statistically significantly more pronounced WMH in the periventricular regions, multiple lacunes and microbleeds, atrophy, severe cognitive impairment and gait disorders compared with MRI type 2. Its formation was associated with a decrease in VEGF-A level. MRI type 2 had the significantly more pronounced juxtacortical WMH, white matter lacunes, in the absence of microbleeds and atrophy, and less severe clinical manifestations compared with MRI type 1. Its formation was associated with an increase in TNF-α level.

CONCLUSION

Clustering of diagnostic MRI signs into MRI types of SVD with significant differences in the severity of clinical manifestations suggests the pathogenetic heterogeneity of age-related SVD. The relationship of MRI types with circulating markers of different mechanisms of vascular wall and brain damage indicates the dominant role of depletion of angiogenesis in the formation of MRI type 1 and increased inflammation in the formation of MRI type 2. Further studies are needed to clarify the criteria and diagnostic value of differentiation of MRI types of SVD, and also their mechanisms with the definition of pathogenetically justified prevention and treatment of various forms of SVD.

Broader Insights into Understanding Tumor Necrosis Factor and Neurodegenerative Disease Pathogenesis Infer New Therapeutic Approaches

Proinflammatory cytokines such as tumor necrosis factor (TNF), with its now appreciated key roles in neurophysiology as well as neuropathophysiology, are sufficiently well-documented to be useful tools for enquiry into the natural history of neurodegenerative diseases. We review the broader literature on TNF to rationalize why abruptly-acquired neurodegenerative states do not exhibit the remorseless clinical progression seen in those states with gradual onsets. We propose that the three typically non-worsening neurodegenerative syndromes, post-stroke, post-traumatic brain injury (TBI), and post cardiac arrest, usually become and remain static because of excess cerebral TNF induced by the initial dramatic peak keeping microglia chronically activated through an autocrine loop of microglial activation through excess cerebral TNF. The existence of this autocrine loop rationalizes post-damage repair with perispinal etanercept and proposes a treatment for cerebral aspects of COVID-19 chronicity. Another insufficiently considered aspect of cerebral proinflammatory cytokines is the fitness of the endogenous cerebral anti-TNF system provided by norepinephrine (NE), generated and distributed throughout the brain from the locus coeruleus (LC). We propose that an intact LC, and therefore an intact NE-mediated endogenous anti-cerebral TNF system, plus the DAMP (damage or danger-associated molecular pattern) input having diminished, is what allows post-stroke, post-TBI, and post cardiac arrest patients a strong long-term survival advantage over Alzheimer's disease and Parkinson's disease sufferers. In contrast, Alzheimer's disease and Parkinson's disease patients remorselessly worsen, being handicapped by sustained, accumulating, DAMP and PAMP (pathogen-associated molecular patterns) input, as well as loss of the LC-origin, NE-mediated, endogenous anti-cerebral TNF system. Adrenergic receptor agonists may counter this.

Perspective of SGLT2 Inhibition in Treatment of Conditions Connected to Neuronal Loss: Focus on Alzheimer's Disease and Ischemia-Related Brain Injury

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are oral anti-hyperglycemic agents approved for the treatment of type 2 diabetes mellitus. Some reports suggest their presence in the central nervous system and possible neuroprotective properties. SGLT2 inhibition by empagliflozin has shown to reduce amyloid burden in cortical regions of APP/PS1xd/db mice. The same effect was noticed regarding tau pathology and brain atrophy volume. Empagliflozin presented beneficial effect on cognitive function, which may be connected to an increase in cerebral brain-derived neurotrophic factor. Canagliflozin and dapagliflozin may possess acetylcholinesterase inhibiting activity, resembling in this matter Alzheimer’s disease-registered therapies. SGLT2 inhibitors may prove to impact risk factors of atherosclerosis and pathways participating both in acute and late stage of stroke. Their mechanism of action can be related to induction in hepatocyte nuclear factor-1α, vascular endothelial growth factor-A, and proinflammatory factors limitation. Empagliflozin may have a positive effect on preservation of neurovascular unit in diabetic mice, preventing its aberrant remodeling. Canagliflozin seems to present some cytostatic properties by limiting both human and mice endothelial cells proliferation. The paper presents potential mechanisms of SGLT-2 inhibitors in conditions connected with neuronal damage, with special emphasis on Alzheimer’s disease and cerebral ischemia.

Alternative Splicing of Putative Stroke/Vascular Risk Factor Genes Expressed in Blood Following Ischemic Stroke Is Sexually Dimorphic and Cause-Specific

Genome-wide association studies have identified putative ischemic stroke risk genes, yet, their expression after stroke is unexplored in spite of growing interest in elucidating their specific role and identifying candidate genes for stroke treatment. Thus, we took an exploratory approach to investigate sexual dimorphism, alternative splicing, and etiology in putative risk gene expression in blood following cardioembolic, atherosclerotic large vessel disease and small vessel disease/lacunar causes of ischemic stroke in each sex compared to controls. Whole transcriptome arrays assessed 71 putative stroke/vascular risk factor genes for blood RNA expression at gene-, exon-, and alternative splicing-levels. Male (n = 122) and female (n = 123) stroke and control volunteers from three university medical centers were matched for race, age, vascular risk factors, and blood draw time since stroke onset. Exclusion criteria included: previous stroke, drug abuse, subarachnoid or intracerebral hemorrhage, hemorrhagic transformation, infection, dialysis, cancer, hematological abnormalities, thrombolytics, anticoagulants or immunosuppressants. Significant differential gene expression (fold change > |1.2|, p < 0.05, partial correlation > |0.4|) and alternative splicing (false discovery rate p < 0.3) were assessed. At gene level, few were differentially expressed: ALDH2, ALOX5AP, F13A1, and IMPA2 (males, all stroke); ITGB3 (females, cardioembolic); ADD1 (males, atherosclerotic); F13A1, IMPA2 (males, lacunar); and WNK1 (females, lacunar). GP1BA and ITGA2B were alternatively spliced in both sexes (all patients vs. controls). Six genes in males, five in females, were alternatively spliced in all stroke compared to controls. Alternative splicing and exon-level analyses associated many genes with specific etiology in either sex. Of 71 genes, 70 had differential exon-level expression in stroke patients compared to control subjects. Among stroke patients, 24 genes represented by differentially expressed exons were male-specific, six were common between sexes, and two were female-specific. In lacunar stroke, expression of 19 differentially expressed exons representing six genes (ADD1, NINJ2, PCSK9, PEMT, SMARCA4, WNK1) decreased in males and increased in females. Results demonstrate alternative splicing and sexually dimorphic expression of most putative risk genes in stroke patients' blood. Since expression was also often cause-specific, sex, and etiology are factors to consider in stroke treatment trials and genetic association studies as society trends toward more personalized medicine.

Review of Genetic Variation as a Predictive Biomarker for Chronic Graft-Versus-Host-Disease After Allogeneic Stem Cell Transplantation

Chronic graft-versus-host disease (cGvHD) is one of the major complications of allogeneic stem cell transplantation (HSCT). cGvHD is an autoimmune-like disorder affecting multiple organs and involves a dermatological rash, tissue inflammation and fibrosis. The incidence of cGvHD has been reported to be as high as 30% to 60% and there are currently no reliable tools for predicting the occurrence of cGvHD. There is therefore an important unmet clinical need for predictive biomarkers. The present review summarizes the state of the art for genetic variation as a predictive biomarker for cGvHD. We discuss three different modes of action for genetic variation in transplantation: genetic associations, genetic matching, and pharmacogenetics. The results indicate that currently, there are no genetic polymorphisms or genetic tools that can be reliably used as validated biomarkers for predicting cGvHD. A number of recommendations for future studies can be drawn. The majority of studies to date have been under-powered and included too few patients and genetic markers. Like in all complex multifactorial diseases, large collaborative genome-level studies are now needed to achieve reliable and unbiased results. Some of the candidate genes, in particular, CTLA4, HSPE, IL1R1, CCR6, FGFR1OP, and IL10, and some non-HLA variants in the HLA gene region have been replicated to be associated with cGvHD risk in independent studies. These associations should now be confirmed in large well-characterized cohorts with fine mapping. Some patients develop cGvHD despite very extensive immunosuppression and other treatments, indicating that the current therapeutic regimens may not always be effective enough. Hence, more studies on pharmacogenetics are also required. Moreover, all of these studies should be adjusted for diagnostic and clinical features of cGvHD. We conclude that future studies should focus on modern genome-level tools, such as machine learning, polygenic risk scores and genome-wide association study-transcription meta-analyses, instead of focusing on just single variants. The risk of cGvHD may be related to the summary level of immunogenetic differences, or whole genome histocompatibility between each donor-recipient pair. As the number of genome-wide analyses in HSCT is increasing, we are approaching an era where there will be sufficient data to incorporate these approaches in the near future.

Effects of tumour necrosis factor on cardiovascular disease and cancer: A two-sample Mendelian randomization study

BACKGROUND

Tumour necrosis factor (TNF) inhibitors are used in the treatment of certain autoimmune diseases but given the role of TNF in tumour biology and atherosclerosis, such therapies may influence the risk of cancer and cardiovascular disease. We conducted a Mendelian randomization study to explore whether TNF levels are causally related to cardiovascular disease and cancer.

METHODS

Single-nucleotide polymorphisms associated with TNF levels at genome-wide significance were identified from a genome-wide association study of 30 912 European-ancestry individuals. Three TNF-associated single-nucleotide polymorphisms associated with higher risk of autoimmune diseases were used as instrumental variables. Summary-level data for 14 cardiovascular diseases, overall cancer and 14 site-specific cancers were obtained from UK Biobank and consortia.

FINDINGS

Genetically-predicted TNF levels were positively associated with coronary artery disease (odds ratio (OR) 2.25; 95% confidence interval (CI) 1.50, 3.37) and ischaemic stroke (OR 2.27; 95% CI 1.50, 3.43), and inversely associated with overall cancer (OR 0.54; 95% CI 0.42, 0.69), breast cancer (OR 0.51; 95% CI 0.39, 0.67), and colorectal cancer (OR 0.20; 95% CI 0.09, 0.45). There were suggestive associations of TNF with venous thromboembolism (OR 2.18; 95% CI 1.32, 3.59), endometrial cancer (OR 0.25; 95% CI 0.07, 0.94), and lung cancer (OR 0.45; 95% CI 0.21, 0.94).

INTERPRETATION

This study found evidence of causal associations of increased TNF levels with higher risk of common cardiovascular diseases and lower risk of overall and certain cancers.

Characterization of the TNF and IL-1 systems in human brain and blood after ischemic stroke

Preclinical and clinical proof-of-concept studies have suggested the effectiveness of pharmacological modulation of inflammatory cytokines in ischemic stroke. Experimental evidence shows that targeting tumor necrosis factor (TNF) and interleukin (IL)-1 holds promise, and these cytokines are considered prime targets in the development of new stroke therapies. So far, however, information on the cellular expression of TNF and IL-1 in the human ischemic brain is sparse.We studied 14 cases of human post-mortem ischemic stroke, representing 21 specimens of infarcts aged 1 to > 8 days. We characterized glial and leukocyte reactions in the infarct/peri-infarct (I/PI) and normal-appearing tissue (NAT) and the cellular location of TNF, TNF receptor (TNFR)1 and TNFR2, IL-1α, IL-1β, and IL-1 receptor antagonist (IL-1Ra). The immunohistochemically stained tissue sections received a score reflecting the number of immunoreactive cells and the intensity of the immunoreactivity (IR) in individual cells where 0 = no immunoreactive cells, 1 = many intermediately to strongly immunoreactive cells, and 2 = numerous and intensively immunoreactive cells. Additionally, we measured blood TNF, TNFR, and IL-1 levels in surviving ischemic stroke patients within the first 8 h and again at 72 h after symptom onset and compared levels to healthy controls.We observed IL-1α and IL-1β IR in neurons, glia, and macrophages in all specimens. IL-1Ra IR was found in glia, in addition to macrophages. TNF IR was initially found in neurons located in I/PI and NAT but increased in glia in older infarcts. TNF IR increased in macrophages in all specimens. TNFR1 IR was found in neurons and glia and macrophages, while TNFR2 was expressed only by glia in I/PI and NAT, and by macrophages in I/PI. Our results suggest that TNF and IL-1 are expressed by subsets of cells and that TNFR2 is expressed in areas with increased astrocytic reactivity. In ischemic stroke patients, we demonstrate that plasma TNFR1 and TNFR2 levels increased in the acute phase after symptom onset compared to healthy controls, whereas TNF, IL-1α, IL-1β, and IL-1Ra did not change.Our findings of increased brain cytokines and plasma TNFR1 and TNFR2 support the hypothesis that targeting post-stroke inflammation could be a promising add-on therapy in ischemic stroke patients.

MRI Types of Cerebral Small Vessel Disease and Circulating Markers of Vascular Wall Damage

The evaluation of the clustering of magnetic resonance imaging (MRI) signs into MRI types and their relationship with circulating markers of vascular wall damage were performed in 96 patients with cerebral small vessel disease (cSVD) (31 men and 65 women; mean age, 60.91 ± 6.57 years). The serum concentrations of the tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor-A (VEGF-A), and hypoxia-inducible factor 1-α (HIF-1α) were investigated in 70 patients with Fazekas stages 2 and 3 of white matter hyperintensities (WMH) and 21 age- and sex-matched volunteers with normal brain MRI using ELISA. The cluster analysis excluded two patients from the further analysis due to restrictions in their scanning protocol. MRI signs of 94 patients were distributed into two clusters. In the first group there were 18 patients with Fazekas 3 stage WMH. The second group consisted of 76 patients with WMH of different stages. The uneven distribution of patients between clusters limited the subsequent steps of statistical analysis; therefore, a cluster comparison was performed in patients with Fazekas stage 3 WMH, designated as MRI type 1 and type 2 of Fazekas 3 stage. There were no differences in age, sex, degree of hypertension, or other risk factors. MRI type 1 had significantly more widespread WMH, lacunes in many areas, microbleeds, atrophy, severe cognitive and gait impairments, and was associated with downregulation of VEGF-A compared with MRI type 2. MRI type 2 had more severe deep WMH, lacunes in the white matter, no microbleeds or atrophy, and less severe clinical manifestations and was associated with upregulation of TNF-α compared with MRI type 1. The established differences reflect the pathogenetic heterogeneity of cSVD and explain the variations in the clinical manifestations observed in Fazekas stage 3 of this disease.

Association between tumor necrosis factor-α gene-1031T/C promoter polymorphism and endometriosis in a European population

Background Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine which plays an important role in the pathogenesis of many diseases. Endometriosis is one of the most common gynecological diseases. The purpose of this study was to investigate the association of TNF-α-1031T/C polymorphism with the genetic susceptibility of endometriosis in a European population. Materials and methods In this case-control study, 51 endometriosis patients and 67 healthy control women participated. We used endometrial tissue from the patients and peripheral blood from the healthy women to extract DNA. Polymerase chain reaction (PCR) analysis and the restriction enzyme Bbs I were used to analyze the -1031 T/C polymorphism in the TNF-α gene promoter region. Statistical analysis was performed using Fisher's exact test. We also calculated the odds ratios. Results In the group of patients, 66.7% of women were detected with the TT genotype, 33.3% with the TC genotype and 0% with the CC genotype while in the control group, 46.3% had the TT genotype, 47.8% had the TC genotype and 6% had the CC genotype. There was a significant association between the TT genotype with endometriosis (p = 0.03). There was no significant deviation from the Hardy-Weinberg equilibrium. Conclusions The TC and CC genotypes appeared more often in the healthy women than the endometriosis patients and this shows that the C allele might have a protective role in endometriosis in the Greek population. Further studies are needed to specify the role of this polymorphism in pathogenesis of endometriosis and the mechanisms that protect the patients from the disease.

TNF-α polymorphisms affect persistence and progression of HBV infection

Background

Hepatitis B virus (HBV) infections are a major threat worldwide. Disease progression and outcome is diverse and depends on host genetic background. Recently, a high rate of HBV reactivation in individuals receiving tumor necrosis factor‐α (TNF‐α) antagonists showed the importance of this cytokine in HBV infection control. Here, we investigated the influence of TNF‐α promoter polymorphisms on susceptibility to chronic HBV infection (CHB), liver injury progression and outcomes.

Methods

A total of 231 patients with CHB constituted the study group and 100 healthy volunteers—the local control group. TNF‐α −1031T/C, −863C/A, −857C/T, −308G/A, and −238G/A were genotyped using MALDI‐TOF mass spectrometry.

Results

TNF‐α −1031C and −863A alleles were observed more frequently in CHB group than in healthy controls. Carriers of TNF‐α −1031C and −863A variant alleles had lower baseline levels of serum HBV DNA and lower liver necroinflammatory activity than dominant homozygotes. A −857CT genotype predisposed to higher necroinflammatory activity. No associations between TNF‐α variants and liver fibrosis were found.

Conclusion

This study indicates that TNF‐α −863A and −1031C alleles are associated with increased susceptibility to CHB in individuals from northern Poland. The same variants determine the course of CHB, lowering viremia and reducing necroinflammatory activity of the liver.

TNF-α-driven inflammation and mitochondrial dysfunction define the platelet hyperreactivity of aging

Aging and chronic inflammation are independent risk factors for the development of atherothrombosis and cardiovascular disease. We hypothesized that aging-associated inflammation promotes the development of platelet hyperreactivity and increases thrombotic risk during aging. Functional platelet studies in aged-frail adults and old mice demonstrated that their platelets are hyperreactive and form larger thrombi. We identified tumor necrosis factor α (TNF-α) as the key aging-associated proinflammatory cytokine responsible for platelet hyperreactivity. We further showed that platelet hyperreactivity is neutralized by abrogating signaling through TNF-α receptors in vivo in a mouse model of aging. Analysis of the bone marrow compartments showed significant platelet-biased hematopoiesis in old mice reflected by increased megakaryocyte-committed progenitor cells, megakaryocyte ploidy status, and thrombocytosis. Single-cell RNA-sequencing analysis of native mouse megakaryocytes showed significant reprogramming of inflammatory, metabolic, and mitochondrial gene pathways in old mice that appeared to play a significant role in determining platelet hyperreactivity. Platelets from old mice (where TNF-α was endogenously increased) and from young mice exposed to exogenous TNF-α exhibited significant mitochondrial changes characterized by elevated mitochondrial mass and increased oxygen consumption during activation. These mitochondrial changes were mitigated upon TNF-α blockade. Similar increases in platelet mitochondrial mass were seen in platelets from patients with myeloproliferative neoplasms, where TNF-α levels are also increased. Furthermore, metabolomics studies of platelets from young and old mice demonstrated age-dependent metabolic profiles that may differentially poise platelets for activation. Altogether, we present previously unrecognized evidence that TNF-α critically regulates megakaryocytes resident in the bone marrow niche and aging-associated platelet hyperreactivity and thrombosis.

Health Benefits of Endurance Training: Implications of the Brain-Derived Neurotrophic Factor-A Systematic Review

This article presents a concept that wide expression of brain-derived neurotrophic factor (BDNF) and its receptors (TrkB) in the nervous tissue, evoked by regular endurance training (ET), can cause numerous motor and metabolic adaptations, which are beneficial for human health. The relationships between the training-evoked increase of endogenous BDNF and molecular and/or physiological adaptations in the nervous structures controlling both motor performance and homeostasis of the whole organism have been presented. Due to a very wide range of plastic changes that ET has exerted on various systems of the body, the improvement of motor skills and counteraction of the development of civilization diseases resulting from the posttraining increase of BDNF/TrkB levels have been discussed, as important for people, who undertake ET. Thus, this report presents the influence of endurance exercises on the (1) transformation of motoneuron properties, which are a final element of the motor pathways, (2) reduction of motor deficits evoked by Parkinson disease, and (3) prevention of the metabolic syndrome (MetS). This review suggests that the increase of posttraining levels of BDNF and its TrkB receptors causes simultaneous changes in the activity of the spinal cord, the substantia nigra, and the hypothalamic nuclei neurons, which are responsible for the alteration of the functional properties of motoneurons innervating the skeletal muscles, for the enhancement of dopamine release in the brain, and for the modulation of hormone levels involved in regulating the metabolic processes, responsively. Finally, training-evoked increase of the BDNF/TrkB leads to a change in a manner of regulation of skeletal muscles, causes a reduction of motor deficits observed in the Parkinson disease, and lowers weight, glucose level, and blood pressure, which accompany the MetS. Therefore, BDNF seems to be the molecular factor of pleiotropic activity, important in the modulation processes, underlying adaptations, which result from ET.

Immunomodulatory Therapeutic Strategies in Stroke

The role of immunity in all stages of stroke is increasingly being recognized, from the pathogenesis of risk factors to tissue repair, leading to the investigation of a range of immunomodulatory therapies. In the acute phase of stroke, proposed therapies include drugs targeting pro-inflammatory cytokines, matrix metalloproteinases, and leukocyte infiltration, with a key objective to reduce initial brain cell toxicity. Systemically, the early stages of stroke are also characterized by stroke-induced immunosuppression, where downregulation of host defences predisposes patients to infection. Therefore, strategies to modulate innate immunity post-stroke have garnered greater attention. A complementary objective is to reduce longer-term sequelae by focusing on adaptive immunity. Following stroke onset, the integrity of the blood–brain barrier is compromised, exposing central nervous system (CNS) antigens to systemic adaptive immune recognition, potentially inducing autoimmunity. Some pre-clinical efforts have been made to tolerize the immune system to CNS antigens pre-stroke. Separately, immune cell populations that exhibit a regulatory phenotype (T- and B- regulatory cells) have been shown to ameliorate post-stroke inflammation and contribute to tissue repair. Cell-based therapies, established in oncology and transplantation, could become a strategy to treat the acute and chronic stages of stroke. Furthermore, a role for the gut microbiota in ischaemic injury has received attention. Finally, the immune system may play a role in remote ischaemic preconditioning-mediated neuroprotection against stroke. The development of stroke therapies involving organs distant to the infarct site, therefore, should not be overlooked. This review will discuss the immune mechanisms of various therapeutic strategies, surveying published data and discussing more theoretical mechanisms of action that have yet to be exploited.

The effect of tumor necrosis factor alpha (-308G/a) and interferon gamma (+874T/a) polymorphisms on susceptibility to coronary heart disease

Background: Coronary heart disease (CHD) is a chronic inflammatory disease, which is still regarded as a major cause of morbidity and mortality worldwide. Several studies have suggested that polymorphisms in cytokine genes are associated with the pathogenesis of CHD. The genotype distribution of Tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) genes polymorphisms have been shown to be different in various ethnic populations. This study was aimed to investigate the association of TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms with risk of CHD in an Iranian population. Methods: A total of 187 unrelated subjects comprised 96 CHD patients and 91 healthy controls were enrolled in this cross-sectional study. The TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms were genotyped using amplification refractory mutation system-PCR (ARMS-PCR). The chi-square and logistic regression tests were used to calculate the odds ratios (ORs) as a measure of differences in genotype frequencies. Results: A significant differences in the allelic and genotypic distribution of TNF-α-308 G/A and IFN-γ + 874T/A polymorphisms was found between CHD patients and healthy controls (P = 0.017, P = 0.011, P = 0.006 and P = 0.002, respectively). Logistic regression analyses were also revealed statistically significant risk for CHD with respect to TNF-α-308 A and IFN-γ + 874 T carriers either in crude or after adjustment for potential confounders (P = 0.003 and P = 0.006, respectively). Conclusion: This study provides strong evidence supporting the association of TNF-α-308G/A and IFN-γ + 874T/A polymorphisms with the increased risk of CHD. Therefore, these two cytokine polymorphisms may play a role in predisposition to coronary heart disease.

TNF-α G-308A genetic variants, serum CRP-hs concentration and DNA damage in obese women

Obesity is associated with inflammation, which can disturb genome stability. Tumor necrosis factor (TNF-α) polymorphism was found to affect TNF-α protein production and inflammation. Therefore, the present study illustrates the relationship between TNF-α polymorphism, the degree of inflammation assessed by serum high sensitivity C-reactive protein concentration (CRP-hs) and basal DNA damage in patients with obesity (BMI 30–34.9 kg/m²) and control subjects with proper body mass (BMI < 25 kg/m²). A total of 115 participants (75 obese premenopausal women; and 40 age-, and gender-matched controls) were included. Biochemical parameters (serum concentrations of total-cholesterol, HDL-cholesterol, LDL- cholesterol, triglycerides, glucose, apolipoprotein AI, CRP-hs) and endogenous DNA damage (determined by comet assay) were measured. TNF-α G-308A polymorphism (rs1800629) was analyzed by PCR-RFLP (PCR-restriction fragments length polymorphism). An effect of TNF-α genotype on serum CRP-hs concentration was noted (p = 0.031). In general, carriers of the rare A allele of the TNF-α G-308A polymorphism had significantly lower endogenous DNA damage and serum CRP-hs concentrations than GG homozygotes, however, the protective effect of the A allele was especially visible in non-obese women. Serum CRP-hs concentrations and levels of DNA damage (% DNA in tail) were significantly higher in obese than in controls (p = 0.001 and p < 0.0001, respectively). The adjusted multiple linear regression analyses revealed a significant, independent impact of obesity on DNA damage (p = 0.00000) and no effect of other covariates i.e. age, TNF-α genotype and serum CRP-hs concentration. Our study showed that obesity has a significant impact on the levels of endogenous DNA damage. Obesity abolished the protective effect of A allele of the TNF-α G-308A polymorphism on DNA damage and on inflammation development observed in non-obese A allele carriers.

Polymorphisms of cytokine genes and tuberculosis in two independent studies

Cytokine gene single nucleotide polymorphisms (SNPs) can influence cytokine levels, which may be associated with tuberculosis (TB) susceptibility. There is evidence that interleukin 1B (IL1B), tumor necrosis factor-alpha (TNF-alpha), and IL6 may be involved in the progression of TB. Using a self-validating case-control design, we selected eleven functional SNPs in IL1B, TNF and IL6 to detect their association with TB in Chinese Han and Tibetan populations. The associations between SNPs and TB were estimated by computing the odds ratios (ORs) and 95% confidence intervals (95% CI) using logistic regression analyses. We found that the IL1B rs16944 polymorphism was associated with decreased risk of TB in the two studies. The G allele at rs2069837 of IL6 was significantly more common in controls than in TB patients in the Han population. Moreover, TNF rs1799964 and rs1800630 were risk factors for susceptibility to TB, which were validated in the Chinese Tibetan population. In addition, TNF rs1799724 and rs1800629 were associated with TB, but only in the Tibetan population. In conclusion, SNPs of the IL1B and TNF gene were associated with TB susceptibility in Chinese Han and Tibetan populations. IL6 polymorphism may be considered as a protective factor for TB in the Chinese Han population, but not the Tibetan population.

Are There Any Common Genetic Risk Markers for Rheumatoid Arthritis and Periodontal Diseases? A Case-Control Study

Background

Several studies suggest that there is a biologically plausible connection between rheumatoid arthritis (RA) and periodontal diseases (PD). Both disorders are characterized as multifactorial diseases potentially sharing common risk factors. Based on the inflammatory nature of RA and PD, the impact of genetic variations of genes of the immune system on both diseases was studied in this study.

Materials and Methods

We conducted a case-control study (n = 201) comparing 101 RA patients suffering from periodontal disease of different severities (no/mild PD vs. severe PD) with 100 systemically healthy controls without RA and severe PD. The genotype, allele, and haplotype distributions of 22 SNPs of 13 pro- and anti-inflammatory cytokines were assessed applying sequence-specific PCR.

Results

Evaluating the impact of cytokine SNPs in RA, we identified the G allele of rs1801275 in IL4Rα (p = 0.043) and the G allele of rs361525 in TNFα (p = 0.005) as disease-associated risk factors in bivariate analyses. In multivariate analyses, these significant associations could not be proven. The A allele of rs2430561 in IFNγ was indicative for severe periodontitis among the patients with rheumatoid arthritis (p = 0.039). Investigating the impact of rs2430561 in IFNγ on comorbidity using binary logistic regression analyses, the A allele was confirmed as an independent risk factor for severe periodontal disease and RA (p = 0.024).

Conclusions

These results emphasize the association of genetic variations in proinflammatory cytokines (TNFα and IFNγ) and cytokine receptor (IL4Rα) and RA and periodontal diseases. In multivariate analyses, the A allele of IFNγ was proven to be a significant marker of RA and PD comorbidities. The study broadens the knowledge about disease-specific differences in genetic composition and provides an improved understanding of a possible association of both diseases.

Evaluate neuroprotective effect of silibinin using chronic unpredictable stress (cus) model

Chronic unpredictable stressors can produce a situation similar to clinical depression, and such animal models can be used for the preclinical evaluation of antidepressants. Many findings have shown that the levels of proinflammatory cytokines (e.g., TNF-α) and oxidative stress (increased lipid peroxidation, decreased glutathione levels, and endogenous antioxidant enzyme activities) are increased in patients with depression. Silibinin is the major active constituent of silymarin, a standardized extract of the milk thistle seeds, containing a mixture of flavonolignans consisting of silibinin, isosilibinin, silicristin, silidianin and exhibit antioxidant activity. Objectives The present study was designed to investigate the effect of silibinin on unpredictable chronic stressinduce behavioral and biochemical alterations in mice.

METHODS

Mice were subjected to different stress paradigms daily for a period of 45 days to induce depressive like behavior such as memory acquisition, and retention.

RESULTS

Chronic treatment with silibinin significantly reversed the unpredictable chronic stress-induced behavioral (improve memory function), biochemical changes (decreased glutathione levels, superoxide dismutas), and inflammation surge (serum TNF-α IL 1β) in stressed mice.

CONCLUSION

The study revealed that silibinin exerted effects in behavioral despair paradigm in chronically stressed mice, specifically by modulating central oxidative stress and inflammation.

Genetics of platelet traits in ischaemic stroke: focus on mean platelet volume and platelet count

Purpose/Aim of the study: The aim of this review is to summarize the role of genetic variants affecting mean platelet volume (MPV) and platelet count (PLT) leading to higher platelet reactivity and in turn to thrombotic events like stroke and cardiovascular diseases.

MATERIALS AND METHODS

A search was conducted in PUBMED, MEDLINE, EMBASE, PROQUEST, Science Direct, Cochrane Library, and Google Scholar related to the studies focussing on genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis that have been employed to identify the genetic variants influencing MPV and PLT.

RESULTS

Antiplatelet agents underscore the crucial role of platelets in the pathogenesis of stroke. Higher platelet reactivity in terms of mean platelet volume (MPV) and platelet count (PLT) contributes significantly to the interindividual variation in platelet reaction at the site of vessel wall injury. Some individuals encounter thrombotic events as platelets get occluded at the site of vessel wall injury whereas others heal the injury without occluding the circulation. Evidence suggests that MPV and PLT have a strong genetic component. High throughput techniques including genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis have identified different genetic variants influencing MPV and PLT.

CONCLUSIONS

Identification of complex genetic cross talks affecting PLT and MPV might help to develop novel treatment strategies in treating neurovascular diseases like stroke.

Therapeutic implications of how TNF links apolipoprotein E, phosphorylated tau, α-synuclein, amyloid-β and insulin resistance in neurodegenerative diseases

While cytokines such as TNF have long been recognized as essential to normal cerebral physiology, the implications of their chronic excessive production within the brain are now also increasingly appreciated. Syndromes as diverse as malaria and lead poisoning, as well as non‐infectious neurodegenerative diseases, illustrate this. These cytokines also orchestrate changes in tau, α‐synuclein, amyloid‐β levels and degree of insulin resistance in most neurodegenerative states. New data on the effects of salbutamol, an indirect anti‐TNF agent, on α‐synuclein and Parkinson's disease, APOE4 and tau add considerably to the rationale of the anti‐TNF approach to understanding, and treating, these diseases. Therapeutic advances being tested, and arguably useful for a number of the neurodegenerative diseases, include a reduction of excess cerebral TNF, whether directly, with a specific anti‐TNF biological agent such as etanercept via Batson's plexus, or indirectly via surgically implanting stem cells. Inhaled salbutamol also warrants investigating further across the neurodegenerative disease spectrum. It is now timely to integrate this range of new information across the neurodegenerative disease spectrum, rather than keep seeing it through the lens of individual disease states.

Atopic diseases/diathesis and subsequent ischemic stroke among patients with bipolar disorder: A nationwide longitudinal study

INTRODUCTION

Previous studies have suggested that both bipolar disorder and atopy are associated with an increased risk of stroke. However, the role of atopic diseases/diathesis in the risk of stroke among patients with bipolar disorder remains unclear.

METHODS

Using Taiwan's National Health Insurance Research Database, we selected 55,593 patients with bipolar disorder between 2002 and 2008, divided them into patients with atopic diseases/diathesis (n = 21,050) and patients without atopic diseases/diathesis (n = 34,543), and observed them until the end of 2011. Patients who experienced a stroke during the follow-up period were identified.

RESULTS

Patients with bipolar disorder and atopic diseases/diathesis had an elevated risk of ischemic stroke (hazard ratio [HR]: 1.44, 95% confidence interval [CI]: 1.25-1.59) compared with patients with only bipolar disorder; a dose-dependent relationship was observed between the number of allergic comorbidities and the risk of ischemic stroke (1 atopic disease, HR: 1.30, 95% CI: 1.13-1.49; 2 atopic diseases, HR: 1.59, 95% CI: 1.33-1.91; ≥ 3 atopic diseases, HR: 2.09, 95% CI: 1.50-2.91).The role of atopic diseases in the risk of hemorrhagic stroke among patients with bipolar disorder was nonsignificant (HR: 0.84, 95% CI: 0.64-1.09).

CONCLUSIONS

Patients with bipolar disorder and atopic diseases/diathesis are more prone to ischemic stroke later in life than are those without atopic diseases/diathesis. Further study is required to investigate the underlying mechanism linking atopy, bipolar disorder, and stroke.

Inhibition of hsa-miR-6086 protects human umbilical vein endothelial cells against TNFα-induced proliferation inhibition and apoptosis via CDH5

MiRNAs are considered as a novel class of biomarkers or treatment targets for cardiovascular diseases. Hsa-miR-6086, a novel mi-RNA, was reported to be downregulated during the differentiation of human embryonic stem cells into endothelial cells (ECs). Interestingly, CDH5 (cadherin 5), encoding a classical cadherin of the cadherin superfamily, is a cellular marker of ECs and has been reported to be a target of hsa-miR-6086. However, the role of hsa-miR-6086 in ECs is virtually unknown. Herein, we report that hsa-miR-6086 was markedly induced by TNFα stimulation in human umbilical vein endothelial cells (HUVECs), whereas CDH5 expression was greatly reduced. Importantly, TNFα-induced suppression of CDH5 expression was largely prevented by inhibiting hsa-miR-6086, and hsa-miR-6086 mimic greatly decrease CDH5 expression in HUVECs, suggesting that the induction of hsa-miR-6086 is responsible for CDH5 downregulation by TNFα. In addition, restoration of CDH5 expression level by either inhibiting hsa-miR-6086 or exogenously expressing CDH5 cDNA that is not affected by hsa-miR-6086 protected HUVECs against TNFα-induced apoptosis and cell growth inhibition. Taken together, our study reveals that hsa-miR-6086 is induced by TNFα and mediates TNFα-induced HUVEC growth inhibition through downregulating CDH5 expression. Hence, hsa-miR-6086 might be a new target for treating TNFα-induced endothelial dysfunction.

Protective Effects of Methotrexate against Proatherosclerotic Cytokines: A Review of the Evidence

There is good epidemiological evidence that patients with autoimmune rheumatic disease states, particularly rheumatoid arthritis, have an increased risk of cardiovascular morbidity and mortality when compared to the general population. The presence of a chronic systemic proinflammatory state in this patient group disrupts the structural and functional integrity of the endothelium and the arterial wall, favouring the onset and progression of atherosclerosis. A significant role in the detrimental effects of inflammation on endothelial function and vascular homeostasis is played by specific proatherosclerotic cytokines such as tumour necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6). Recent systematic reviews and meta-analyses have shown that treatment with methotrexate, a first-line disease-modifying antirheumatic drug (DMARD), is associated with a significant reduction in atherosclerosis-mediated cardiovascular events, such as myocardial infarction and stroke, and mortality, when compared to other DMARDs. This suggests that methotrexate might exert specific protective effects against vascular inflammation and atherosclerosis in the context of autoimmune rheumatic disease. This review discusses the available evidence regarding the potential antiatherosclerotic effects of methotrexate through the inhibition of TNF-α, IL-1, and IL-6 and provides suggestions for future experimental and human studies addressing this issue.

Tim-4 expression increases in ischemic stroke patients and is associated with poor outcome

T cell immunoglobin and mucin domain (Tim)-4 on monocytes is involved in immune regulation. Here, we investigated Tim-4 expression on circulating monocytes and in plasma of ischemic stroke. Tim-4 expression was significantly increased on day 2 and day 5 after stroke. Furthermore, stroke severity was positively correlated with Tim-4 expression on monocytes or in plasma. Increased Tim-4 expression was related to stroke associated with infection (SAI) on day 2. Up-regulated Tim-4 expression on monocytes or in plasma on day 2 was a risk predictor of outcome. Our findings suggest that Tim-4 can act as a prognostic biomarker of ischemic stroke.

The effect of exercise interventions on inflammatory biomarkers in healthy, physically inactive subjects: a systematic review

BACKGROUND

Increases in physical activity ameliorate low-grade systemic inflammation in disease populations such as type 2 diabetes mellitus and coronary artery disease. The effects of aerobic and resistance training (RT) on inflammatory biomarker profiles in non-disease, physically inactive individuals are unknown.

METHODS

A systematic review of randomized controlled trials measuring the effect of aerobic and resistance exercise on pro-inflammatory biomarkers in healthy, inactive adult populations was conducted. The available peer-reviewed literature was searched from January 1990 to June 2016 using the electronic databases PubMed and Scopus. A narrative synthesis of review findings was constructed with discussion of the impact of aerobic, resistance and combined training on C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8, interleukin-1β and tumour necrosis factor-α.

RESULTS

The initial search revealed 1596 potentially relevant studies. Application of the study eligibility criteria led to the full-text review of 54 articles with 11 studies deemed suitable for inclusion. Review of related articles and the reference lists of the 54 full-text articles led to the inclusion of 2 additional studies. The review revealed inconsistent findings relating to the effect of aerobic training and RT on CRP and IL-6. Studies of older-aged adults (>65 years old) demonstrated the greatest and most consistent reduction in inflammatory biomarkers post-training intervention.

CONCLUSIONS

A paucity of evidence exists relating to the effect of exercise training on inflammatory markers in non-disease, physically inactive adults. The available evidence suggests potential for the greatest benefit to be seen in older populations and with higher intensity aerobic exercise.

The putative role of environmental aluminium in the development of chronic neuropathology in adults and children. How strong is the evidence and what could be the mechanisms involved?

The conceptualisation of autistic spectrum disorder and Alzheimer's disease has undergone something of a paradigm shift in recent years and rather than being viewed as single illnesses with a unitary pathogenesis and pathophysiology they are increasingly considered to be heterogeneous syndromes with a complex multifactorial aetiopathogenesis, involving a highly complex and diverse combination of genetic, epigenetic and environmental factors. One such environmental factor implicated as a potential cause in both syndromes is aluminium, as an element or as part of a salt, received, for example, in oral form or as an adjuvant. Such administration has the potential to induce pathology via several routes such as provoking dysfunction and/or activation of glial cells which play an indispensable role in the regulation of central nervous system homeostasis and neurodevelopment. Other routes include the generation of oxidative stress, depletion of reduced glutathione, direct and indirect reductions in mitochondrial performance and integrity, and increasing the production of proinflammatory cytokines in both the brain and peripherally. The mechanisms whereby environmental aluminium could contribute to the development of the highly specific pattern of neuropathology seen in Alzheimer's disease are described. Also detailed are several mechanisms whereby significant quantities of aluminium introduced via immunisation could produce chronic neuropathology in genetically susceptible children. Accordingly, it is recommended that the use of aluminium salts in immunisations should be discontinued and that adults should take steps to minimise their exposure to environmental aluminium.

Sex differences in vascular physiology and pathophysiology: estrogen and androgen signaling in health and disease

Sex differences between women and men are often overlooked and underappreciated when studying the cardiovascular system. It has been long assumed that men and women are physiologically similar, and this notion has resulted in women being clinically evaluated and treated for cardiovascular pathophysiological complications as men. Currently, there is increased recognition of fundamental sex differences in cardiovascular function, anatomy, cell signaling, and pathophysiology. The National Institutes of Health have enacted guidelines expressly to gain knowledge about ways the sexes differ in both normal function and diseases at the various research levels (molecular, cellular, tissue, and organ system). Greater understanding of these sex differences will be used to steer future directions in the biomedical sciences and translational and clinical research. This review describes sex-based differences in the physiology and pathophysiology of the vasculature, with a special emphasis on sex steroid receptor (estrogen and androgen receptor) signaling and their potential impact on vascular function in health and diseases (e.g., atherosclerosis, hypertension, peripheral artery disease, abdominal aortic aneurysms, cerebral aneurysms, and stroke).

Translating the biology of adipokines in atherosclerosis and cardiovascular diseases: Gaps and open questions

AIM

Critically discuss the available data, to identify the current gaps and to provide key concepts that will help clinicians in translating the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

DATA SYNTHESIS

Adipose tissue is nowadays recognized as an active endocrine organ, a function related to the ability to secrete adipokines (such as leptin and adiponectin) and pro-inflammatory cytokines (tumor necrosis factor alpha and resistin). Studies in vitro and in animal models have observed that obesity status presents a chronic low-grade inflammation as the consequence of the immune cells infiltrating the adipose tissue as well as adipocytes. This inflammatory signature is often related to the presence of cardiovascular diseases, including atherosclerosis and thrombosis. These links are less clear in humans, where the role of adipokines as prognostic marker and/or player in cardiovascular diseases is not as clear as that observed in experimental models. Moreover, plasma adipokine levels might reflect a condition of adipokine-resistance in which adipokine redundancy occurs. The investigation of the cardio-metabolic phenotype of carriers of single nucleotide polymorphisms affecting the levels or function of a specific adipokine might help determine their relevance in humans. Thus, the aim of the present review is to critically discuss the available data, identify the current gaps and provide key concepts that will help clinicians translate the biology of adipokines in the context of atherosclerosis and cardio-metabolic diseases.

Genetic and serum biomarker evidence for a relationship between TNFα and PTSD in Vietnam war combat veterans

BACKGROUND

Posttraumatic stress disorder (PTSD) is associated with increased inflammation and comorbid medical conditions. However, study findings for individual inflammatory marker levels have been inconsistent. Some research suggests that resilience may play a role in decreased inflammation. A polymorphism in the promoter region of the tumor necrosis factor α gene (TNFα), TNFA -308 (rs1800629) is associated with psychiatric illness but its role in PTSD is yet to be elucidated.

OBJECTIVE

This study investigates a key inflammatory marker, TNFα, for its role in PTSD severity.

METHOD

In a cohort of trauma-exposed Vietnam War veterans (n=299; 159 cases, 140 controls) TNF α serum levels and TNFα polymorphism rs1800629 were correlated with PTSD severity and resilience scores.

RESULTS

The polymorphism was associated with PTSD severity (p=0.045). There were significant group differences between cases and controls with regards to serum TNFα levels (p=0.036). Significant correlations were found between PTSD severity and elevated TNFα levels (r=0.153; p=0.009), and between resilience and decreased TNFα levels at a trend level (p=0.08) across the entire cohort. These relationships were non-significant after controlling for covariates. In the PTSD diagnostic group, a correlation of TNFα and PTSD severity was observed on a trend level (p=0.06), the relationship between TNFα and resilience remained non-significant.

CONCLUSIONS

To our knowledge, this is the first time rs1800629 has been investigated in PTSD contributing to a growing body of literature that identifies the GG as a risk genotype for psychiatric disorders in Caucasian cohorts. However, more research is needed to replicate our results in larger, equally well-characterized cohorts. The relationship between serum TNFα levels and PTSD severity and resilience requires further investigation.