Interleukin-6 (IL-6) and the prognosis of abdominal aortic aneurysms

Causal association between Neuroticism and risk of aortic aneurysm: A bidirectional two-sample Mendelian randomization study

BACKGROUND

The objective of this study was to analyze the causal relationship between Neuroticism and aortic aneurysm using Mendelian randomization (MR). The study aimed to establish a foundation for the development of effective prevention and treatment strategies.

METHODS

Genetic association data for Neuroticism were obtained from the UK Biobank, which included 393,411 individuals and 11,968,760 single nucleotide polymorphisms (SNPs). Genetic association data for aortic aneurysm were obtained from a genome-wide association study (GWAS), which included 479,194 individuals and 24,191,825 SNPs. Heterogeneity was assessed using the Cochran's Q statistic test. The study also utilized the MR Pleiotropy RESidual Sum and Outlier (Mr-PRESSO) test, as well as the MR-Egger regression method, to examine horizontal pleiotropy and determine the reliability of the findings through the leave-one-out method.

RESULTS

Forward MR analysis showed that the risk of aortic aneurysm was elevated in individuals with genetically predicted Neuroticism compared to those without Neuroticism (OR = 1.1315, 95 % CI: 1.0269-1.2468; P = 0.0126). The Cochran's Q test showed no heterogeneity (P > 0.05), and the MR-PRESSO test did not identify instrumental variables of horizontal pleiotropy (P > 0.05). The MR analysis remained robust after removing SNPs one by one. Inverse MR analysis did not observe an association between aortic aneurysm and having Neuroticism OR = 1.030, 95 % CI: 0.9459-1.118, P = 0.488).

CONCLUSION

Our study has established a clear causal relationship between genetically determined Neuroticism and the development of aortic aneurysms. It is therefore important to intensify screening and prevention efforts for aortic aneurysms in neurotic patients. It also opens new avenues for exploring the disease's pathogenesis.

Global research status analysis of the association between aortic aneurysm and inflammation: a bibliometric analysis from 1999 to 2023

Background

Aortic aneurysm is a chronic arterial disease that can lead to aortic rupture, causing severe complications and life-threatening risks for patients, and it is one of the common causes of death among the elderly. Increasing evidence suggests that inflammation plays an important role in the progression of aortic aneurysm. However, there is a lack of literature-based quantitative analysis in this field.

Methods

Up to March 30, 2023, we collected 3,993 articles related to aortic aneurysm and inflammation from the Web of Science Core Collection (WoSCC) database for bibliometric analysis. The collected literature data were subjected to visual analysis of regional distribution, institutions, authors, keywords, and other information using tools such as CiteSpace, VOSviewer, the R package "bibliometric," and online platforms.

Results

The number of publications in this research field has been steadily increasing each year, with the United States and China being the main contributing countries. Harvard University in the United States emerged as the most active and influential research institution in this field. Jonathan Golledge and Peter Libby were identified as the authors with the highest publication output and academic impact, respectively. Researchers in this field tend to publish their findings in influential journals such as the Journal of Vascular Surgery and Arteriosclerosis Thrombosis and Vascular Biology. "Abdominal aortic aneurysm," "giant cell arteritis," "arterial stiffness," and "smooth muscle cells" were identified as the hottest topics in the field of aortic aneurysm and inflammation. In terms of keyword co-occurrence analysis, "Clinical relevant studies of AA" (red), "Inflammatory activation" (green), "Inflammatory mechanisms related to pathogenesis" (dark blue), "Cytokines" (yellow), "Risk factors" (purple), and "Pathological changes in vascular wall" (cyan) formed the major research framework in this field. "Inflammation-related pathogenesis" and "inflammation activation" have emerged as recent hot research directions, with "monocytes," "progression," and "proliferation" being the prominent topics.

Conclusion

This study provides a comprehensive analysis of the knowledge network framework and research hotspots in the field of aortic aneurysm and inflammation through a literature-based quantitative approach. It offers valuable insights to guide scholars in identifying meaningful research directions in this field.

C-reactive protein to albumin ratio provides important long-term prognostic information in patients undergoing endovascular abdominal aortic repair

BACKGROUND

The prognostic value of C-reactive protein/albumin ratio (CAR) is of import in cardiovascular diseases. Our aim was to evaluate the impact of the CAR in patients with asymptomatic abdominal aortic aneurysm (AAA) undergoing endovascular aneurysm repair (EVAR).

MATERIAL AND METHOD

We retrospectively evaluated 127 consecutive patients who underwent technically successful elective EVAR procedure between December 2014 and September 2020. The optimal CAR cut-off value was determined by using receiver operating characteristic (ROC) curve analysis. Based on the cut-off value, we investigated the association of CAR with long-term all-cause mortality.

RESULTS

32 (25.1%) of the patients experienced all-cause mortality during a mean 32.7 ± 21.7 months' follow-up. In the group with mortality, CAR was significantly higher than in the survivor group (4.63 (2.60-11.88) versus 1.63 (0.72-3.24), p < 0.001). Kaplan-Meier curves showed a higher incidence of all-cause mortality in patients with high CAR compared to patients with low CAR (log-rank test, p < 0.001). Multivariable Cox regression analysis revealed that glucose ≥ 110 mg/dL (HR: 2.740; 95% CI: 1.354-5.542; p = 0.005), creatinine ≥ 0.99 mg/dL (HR: 2.957, 95% CI: 1.282-6.819, p = 0.011) and CAR > 2.05 (HR: 8.190, 95% CI: 1.899-35.320, p = 0.005) were the independent predictors of mortality.

CONCLUSION

CAR was associated with a significant increase in postoperative long-term mortality in patients who underwent EVAR. Preoperatively calculated CAR can be used as an important prognostic factor.

Purinergic receptor P2 × 7 contributes to abdominal aortic aneurysm development via modulating macrophage pyroptosis and inflammation

The purinergic receptor P2 × 7 has been established as an important mediator of inflammation and participates in a variety of cardiovascular diseases including atherosclerosis, however, its role in abdominal aortic aneurysms (AAA) remains unclear. In this study, we demonstrate that P2 × 7 plays essential roles in AAA development via modulating macrophage pyroptosis and inflammation. P2 × 7 is highly expressed in human AAA specimen, as well as in experimental murine AAA lesions (both CaCl₂-and Angiotensin Ⅱ-induced AAA models), and it mainly confines in macrophages. Furthermore, P2 × 7 deficiency or pharmacological inhibition with its antagonist could significantly attenuate aneurysm formation in experimental murine AAA models, while P2 × 7 agonist could promote AAA development. The caspase-I activity, matrix metalloproteinase (MMP) activity, reactive oxygen species (ROS) production and pro-inflammatory gene expression were significant reduced in experimental AAA lesions in mice with P2 × 7 deficiency or inhibition. Mechanistically, macrophage P2 × 7 can mediate the activation of NLRP3 inflammasome and activate its downstream caspase-1 to initiate the pyroptosis pathway. After caspase-1 activation, it further cleaves pro-interleukin (IL)-1β and gasdermin D (GSDMD). Consequently, the N-terminal fragment of GSDMD forms pores on the cell membrane, leading to macrophage pyroptosis and release of the pro-inflammatory factor IL-1β. The resulting vascular inflammation further leads to the upregulation of MMP and ROS, thereby promoting AAA development. In summary, these data identify P2 × 7-mediated macrophage pyroptosis signaling pathway as a novel contributory mechanism of AAA formation.

Association of Genetic Polymorphisms and Serum Levels of miR-1-3p with Postoperative Mortality following Abdominal Aortic Aneurysm Repair

BACKGROUND

Several miRNAs have been implicated in the clinical outcomes of cardiovascular disorders, but the role of miR-1-3p in abdominal aortic aneurysm (AAA) prognosis remains unclear. This study aimed to investigate the correlation of single nucleotide polymorphisms (SNPs) in pri-miR-1-3p and mature miR-1-3p expression with postoperative mortality of AAA patients.

METHODS

A total of 230 AAA patients who received AAA repair were recruited and followed up for 5 years. SNP genotyping was carried out using KASP method and relative expression of serum miR-1-3p was measured with qRT-PCR.

RESULTS

Multivariate Cox regression analyses showed that both rs2155975 and rs4591246 variant genotypes were associated with increased all-cause mortality of postoperative AAA patients after adjusting possible confounders. Patients who died tended to have lower baseline miR-1-3p expression (overall and for age < 65 years, aneurysm-related death or cardiac death subgroup) when compared to alive patients; further Cox regression yielded an independent relationship of preoperative low serum miR-1-3p levels with incidents of all-cause death. Patients carrying rs2155975 AG + GG or rs4591246 AG + AA genotype had a higher ratio of low miR-1-3p levels in contrast to those with AA or GG genotype, respectively. The Kaplan-Meier survival curves suggested that the combined genotype in rs2155975 or rs4591246 and low miR-1-3p levels could decrease the overall survival of AAA patients during 5-year follow-up.

CONCLUSIONS

This pilot study demonstrated the importance of rs2155975 and rs4591246 polymorphisms and baseline serum miR-1-3p levels as promising markers to predict mortality among patients following AAA repair.

Signaling through the IL-6-STAT3 Pathway Promotes Proteolytically-Active Macrophage Accumulation Necessary for Development of Small AAA

INTRODUCTION

Elevated interleukin-6 (IL-6) plasma levels have been associated with abdominal aortic aneurysm (AAA), but whether this cytokine plays a causative role in the degenerative remodeling or represents an effect from the inflammatory cascades initiated by infiltrating leukocytes remained unclear. This project aims to demonstrate that within the aortic wall, signaling from IL-6 through the STAT3 transcription factor is necessary for infiltration of proteolytically-active macrophages and development of small AAA.

METHODS

Following measurement of baseline infrarenal aortic diameter (AoD, digital microscopy), C57Bl/6 and IL-6 knockout (IL-6KO) mice underwent AAA induction by application of peri-adventitial CaCl₂ (0.5 M) +/- implantation of an osmotic mini-pump delivering IL-6 (4.36 µg/kg/day over 21 days). At the terminal procedure, AoDs were measured by digital microscopy and aortas harvested for immunoblot (pSTAT3/STAT3), matrix metalloproteinase (MMP) quantification, or flow cytometric analysis of macrophage content. Plasma was collected for cytokine analysis.

RESULTS

IL-6 infusion significantly increased the plasma IL-6 levels in C57Bl/6 and IL-6KO animals. The C57Bl/6 + CaCl₂ group developed AAA (AoD >50% above baseline) but IL-6KO + CaCl₂ did not. In the IL-6KO + IL-6+CaCl2 group, AAA developed to match that of C57Bl/6 + CaCl₂ mice. STAT3 activity was significantly increased in animals with advanced stages of dilation (>40% from baseline), compared to those with ectasia (≤25%). Although cytokine profiles did not support T-cells or neutrophils as being active contributors in this stage of aortic remodeling, changes in the profile of elaborated MMPs suggested macrophage activity with a trend toward alternatively activated pathways. Flow cytometry confirmed significantly increased macrophage abundance specifically in animals with upregulated STAT3 activity and advanced aortic dilation.

CONCLUSION

In this murine model of AAA, progressive dilation to development of true AAA was only accomplished when IL-6 signaling upregulated STAT3 activity to effect accumulation of proteolytically-active macrophages. This pathway warrants further investigation to identify potential therapeutic avenues to abrogate growth of small AAA.

Plasma complement component C2: a potential biomarker for predicting abdominal aortic aneurysm related complications

Blood-based adjunctive measures that can reliably predict abdominal aortic aneurysm (AAA)-related complications hold promise for mitigating the AAA disease burden. In this pilot study, we sought to evaluate the prognostic performance of complement factors in predicting AAA-related clinical outcomes. We recruited consecutive AAA patients (n = 75) and non-AAA patients (n = 75) presenting to St. Michael's Hospital. Plasma levels of complement proteins were assessed at baseline, as well as prospectively measured regularly over a period of 2 years. The primary outcome was the incidence of rapidly progressing AAA (i.e. aortic expansion), defined as change in AAA diameter by either 0.5 cm in 6 months, or 1 cm in 12 months. Secondary outcomes included incidence of major adverse aortic events (MAAE) and major adverse cardiovascular events (MACE). All study outcomes (AAA diameter, MACE and MAAE) were obtained during follow-up. Multivariable adjusted Cox regression analyses were performed to assess the prognostic value of plasma C2 levels in patients with AAA regarding rapid aortic expansion and MAAE and MACE. Event-free survival rates of both groups were also compared. Compared to non-AAA patients, patients with AAA demonstrated significantly higher plasma concentrations of C1q, C4, Factor B, Factor H and Factor D, and significantly lower plasma concentrations of C2, C3, and C4b (p = 0.001). After a median of 24 months from initial baseline measurements, C2 was determined as the strongest predictor of rapid aortic expansion (HR 0.10, p = 0.040), MAAE (HR 0.09, p = 0.001) and MACE (HR 0.14, p = 0.011). Based on the data from the survival analysis, higher levels of C2 at admission in patients with AAA predicted greater risk for rapid aortic expansion and MAAE (not MACE). Plasma C2 has the potential to be a biomarker for predicting rapid aortic expansion, MAAE, and the eventual need for an aortic intervention in AAA patients.

Epicardial adipose tissue volume is associated with abdominal aortic aneurysm expansion

BACKGROUND

Epicardial adipose tissue volume (EATV) is associated with cardiovascular diseases such as coronary artery disease. However, no information is available regarding the relationship between EATV and abdominal aortic aneurysm (AAA) expansion. This study aimed to evaluate the association between EATV and the growth of AAA, and to identify predictors of AAA expansion.

METHODS

Between June 2009 and December 2019, a total of 906 patients underwent endovascular or open repair of AAA at our institution. Patients with previous cardiac surgery, previous ascending thoracic aortic surgery, ruptured AAA, infected AAA, inflammatory AAA, saccular aneurysm, solitary iliac aneurysm, or reintervention after treatment for AAA were excluded. Two hundred and thirty-seven patients with at least two preoperative computed tomography (CT) scans performed more than 180 days apart were included in this study. EATV within the pericardium was retrospectively quantified from preoperative non-contrast CT images using a 3D workstation. The EATV index was defined as EATV divided by body surface area. The AAA expansion rate was defined as the increase in AAA diameter per year, and patients were divided into the slow-expansion group, with an expansion rate < 5 mm/year, and the fast-expansion group, with an expansion rate ≥ 5 mm/year. The correlation between expansion rate and the EATV index was analyzed, and the cut-off value of the EATV index was determined using a receiver operating characteristics curve. Multivariate analysis was used to assess predictors of the AAA expansion rate.

RESULTS

The expansion rate of AAA was positively correlated with the EATV index (R = .237, P < .001). The initial aneurysm diameter (P < .001) and EATV index (P = .009) differed significantly between the two groups. The cut-off value of the EATV index was 60.3 cm³/m² (area under the curve, .658; 95% confidence interval [CI], .568-.749; sensitivity, 1.000; specificity, .309). Multivariate analysis revealed that the initial aneurysm diameter and an EATV index > 60.3 cm³/m² were significantly associated with the AAA expansion rate.

CONCLUSIONS

This study demonstrated that the EATV index was associated with AAA expansion.

Cytokines in Abdominal Aortic Aneurysm: Master Regulators With Clinical Application

Abdominal aortic aneurysm (AAA) is a potentially life-threatening disorder with a mostly asymptomatic course where the abdominal aorta is weakened and bulged. Cytokines play especially important roles (both positive and negative) among the molecular actors of AAA development. All the inflammatory cascades, extracellular matrix degradation and vascular smooth muscle cell apoptosis are driven by cytokines. Previous studies emphasize an altered expression and a changed epigenetic regulation of key cytokines in AAA tissue samples. Such cytokines as IL-6, IL-10, IL-12, IL-17, IL-33, IL-1β, TGF-β, TNF-α, IFN-γ, and CXCL10 seem to be crucial in AAA pathogenesis. Some data obtained in animal studies show a protective function of IL-10, IL-33, and canonical TGF-β signaling, as well as a dual role of IL-4, IFN-γ and CXCL10, while TNF-α, IL-1β, IL-6, IL-12/IL-23, IL-17, CCR2, CXCR2, CXCR4 and the TGF-β noncanonical pathway are believed to aggravate the disease. Altogether data highlight significance of cytokines as informative markers and predictors of AAA. Pathologic serum/plasma concentrations of IL-1β, IL-2, IL-6, TNF-α, IL-10, IL-8, IL-17, IFN-γ, and PDGF have been already found in AAA patients. Some of the changes correlate with the size of aneurysms. Moreover, the risk of AAA is associated with polymorphic variants of genes encoding cytokines and their receptors: CCR2 (rs1799864), CCR5 (Delta-32), IL6 (rs1800796 and rs1800795), IL6R (rs12133641), IL10 (rs1800896), TGFB1 (rs1800469), TGFBR1 (rs1626340), TGFBR2 (rs1036095, rs4522809, rs1078985), and TNFA (rs1800629). Finally, 5 single-nucleotide polymorphisms in gene coding latent TGF-β-binding protein (LTBP4) and an allelic variant of TGFB3 are related to a significantly slower AAA annual growth rate.

Association between gene polymorphism of inflammatory factors, thrombogenic factors, and stress-related proteins and abdominal aortic aneurysm: A meta-analysis and systematic review

BACKGROUND

Abdominal aortic aneurysm (AAA) is a deadly disease in the elderly population. Currently, the association between single nucleotide polymorphisms (SNPs) and the presence of AAAs has become a hot topic and is a concern for many researchers.

METHOD

We performed a document retrieval in PubMed, EMBASE, and the Cochrane Library (to January 2020). A total of 17 case-control reports on SNPs of AAAs and eight SNPs of correlation factors were selected. All essential data, including race, age, country, criteria of AAA diagnosis, method of AAA measurement, method of genotype detection, name of SNPs, minor allele frequency (MAF), Hardy Weinberg equilibrium (HWE) of the control group, and number of cases and control groups were extracted by two reviewers independently. The fixed-effect model and random-effect model were used to calculate the overall odds ratios (ORs) and 95% confidence intervals (CIs). The association between selected SNPs and the presence of AAAs was evaluated under different genetic models (dominant, codominant, recessive, overdominant, and allele models).

RESULTS

A total of 17 articles (sample size ranging from to 42-665 AAA cases and 49-2,297 controls) and 23 SNPs of related factors were identified. Eight SNPs were assessed in at least two studies and were selected for further meta-analysis. We found that the A allele of interleukin (IL)-10 (-1082 G/A) (OR: 1.35, 95% CI: 1.18-1.54, p < 0.0001) was a risk factor for AAAs under random and fixed-effect models. In addition, partial genetic models of these SNPs were confirmed to be related to the presence of AAA. Subgroup analysis revealed that haptoglobin (HP)-1 was a risk factor for AAAs (OR: 1.30, 95% CI: 1.04-1.63, p = 0.02) in the European population. No association was found between the occurrence of AAA and the other SNPs.

CONCLUSION

In our current meta-analysis, we speculated that the genotype distribution of IL-10 (-1082 G/A) may be associated with the emergence of AAA.

Abdominal Aortic Aneurysm Formation with a Focus on Vascular Smooth Muscle Cells

Abdominal aortic aneurysm (AAA) is a lethal degenerative vascular disease that affects, mostly, the elder population, with a high mortality rate (>80%) upon rupture. It features a dilation of the aortic diameter to larger than 30 mm or more than 50%. Diverse pathological processes are involved in the development of AAA, including aortic wall inflammation, elastin breakdown, oxidative stress, smooth muscle cell (SMC) phenotypic switching and dysfunction, and extracellular matrix degradation. With open surgery being the only therapeutic option up to date, the lack of pharmaceutical treatment approach calls for identifying novel and effective targets and further understanding the pathological process of AAA. Both lifestyle and genetic predisposition have an important role in increasing the risk of AAA. Several cell types are closely related to the pathogenesis of AAA. Among them, vascular SMCs (VSMCs) are gaining much attention as a critical contributor for AAA initiation and/or progression. In this review, we summarize what is known about AAA, including the risk factors, the pathophysiology, and the established animal models of AAA. In particular, we focus on the VSMC phenotypic switching and dysfunction in AAA formation. Further understanding the regulation of VSMC phenotypic changes may provide novel therapeutic targets for the treatment or prevention of AAA.

Is there a correlation between -174(G/C) polymorphism of IL-6 gene and the incidence of acute myocardial infarction?

Background

Cardiovascular disease (CVD) remains the major cause of death worldwide. Most CVD can be prevented by addressing risk factors. Acute myocardial infarction (AMI) is an inflammatory disorder characterized by changes in several cytokines including the interleukins (ILs). Studies are running to evaluate the genetic variation in the inflammatory system and their influence on the risk factors for CVD aiming for future prevention of this global disease. The aim of the current study was too investigate the association of -174 (G/C) IL-6 polymorphism with the incidence of AMI in a representative sector of the Egyptian population and to examine the contribution of IL-6, as a biomarker, in the pathogenesis of AMI. Genotyping of -174 (G/C) IL-6 polymorphism was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) while IL-6 levels were assayed by ELISA.

Results

The genotype distribution of -174 (G/C) IL-6 gene was not significantly different between the control subjects (GG 81.7%, GC 16.3%, CC 1.9%) and the AMI patients (GG 79%, GC 19%, CC 2%).The serum levels of IL-6 were significantly elevated in the AMI patients in comparison to the control subjects (P < 0.0001).

Conclusions

There is no significant association of -174(G/C) polymorphism in the promoter sequence of IL-6 and the incidence of AMI in the examined sample of Egyptian population. Elevated levels of serum IL-6 confirmed the relationship between inflammation and the incidence of AMI.

Smoking, Hypertension, and GG Genotype of the IL-6 rs1800796 Polymorphism are Independent Risk Factors for Abdominal Aortic Aneurysm in Han Population

Background

Recent researches have investigated the link between the rs1800796 polymorphism (−572G/C) in the interleukin-6 (IL-6) gene and the risk of abdominal aortic aneurysm (AAA). However, no Chinese studies have addressed the association between the risk of AAA and this polymorphism.

Methods

This case-control study included 153 AAA patients and 205 controls. Diabetes mellitus, hypertension, dyslipidemia, and coronary artery disease (CAD) status were collected. The AAA and control groups were 69.20 ± 7.56 and 68.50 ± 7.12 years old, respectively.

Results

The analysis revealed that the G allele and GG genotype of the IL-6 rs1800796 polymorphism were remarkedly correlated with an elevated risk of AAA. The GG genotype displayed an association with the risk of AAA after adjustment for gender, body mass index, age, drinking, and smoking. Subgroup analyses indicated that this polymorphism elevated the risk of AAA among males, individuals aged ≥70 years, smokers, drinkers, individuals with a body mass index (BMI) ≥25 kg/m², patients without diabetes, and patients with hypertension. Univariate and multivariate analyses indicated that smoking, hypertension, and the GG genotype (rs1800796 polymorphism) were independently related with the risk of AAA.

Conclusion

The IL-6 rs1800796 polymorphism increases the risk of AAA. In addition, smoking, hypertension, and the GG genotype of the rs1800796 polymorphism are independent risk factors for AAA. Further studies of Chinese populations are needed to validate these findings.

Polymorphisms in the IL-6 and TNF-α gene are associated with an increased risk of abdominal aortic aneurysm

BACKGROUND

An abdominal aortic aneurysm (AAA) is a complex disease of the aging population that is associated with inflammation and the cellular immune response. To investigate the influence of interleukin (IL)-6 and tumor necrosis factor (TNF)-α single nucleotide polymorphisms (SNPs) on the risk of AAA formation and progression, the frequency of AAA and its associated risk factors were determined.

METHOD

Four SNPs in the IL-6 (-174G/C, rs1800795; -572G/C, rs1800796) and TNF-α (-238G/A, rs361525; -308G/A, rs1800629) genes were studied by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in patients with AAA and healthy volunteers. The mRNA expression and plasma IL-6 and TNF-α levels were also determined.

RESULTS

A mutation detected in at least one allele of the IL-6 -174G/C SNP was associated with a 2-fold increased risk of AAA occurrence (OR: 2.08; 95% CI: 1.15-3.76; p = 0.014, in the dominant model). An increased risk of AAA incidence among heterozygous carriers of the TNF-α - 308G/A genotype was observed (OR: 2.06; 95% CI: 1.17-3.62; p = 0.011, in the overdominant model). The wild-type genotypes of the IL-6 -174G/C and the TNF-α -308G/A SNPs coexisted more frequently in healthy subjects than in AAA patients and was associated with decreased risk of AAA (p < 0.001). Moreover, elevated levels of IL-6 and TNF-α were associated with an increased risk of hypertension (p < 0.001 and p = 0.022, respectively).

CONCLUSIONS

The IL-6 -174G/C and the TNF-α -238G/A gene polymorphisms are associated with an increased risk of abdominal aortic aneurysm development.

The role of autophagy in abdominal aortic aneurysm: protective but dysfunctional

Autophagy, an evolutionarily conserved mechanism that promotes cell survival by recycling nutrients and degrading long-lived proteins and dysfunctional organelles, is an important defense mechanism, and its attenuation has been well documented in senescence and aging-related diseases. Abdominal aortic aneurysm (AAA), a well-known aging-related disease, has been defined as a chronic degenerative process in the abdominal aortic wall; however, the complete mechanism is unknown, and a clinical treatment is lacking. Accumulating evidence has recently revealed that numerous drugs that can induce autophagy are effective in the treatment of AAA. The purpose of this systematic review was to focus on the cross-talk between autophagy and high-risk factors and the potential pathogenesis of AAA to understand not only the host defense and pathogenesis but also potential treatments.

A comparison of a ketogenic diet with a LowGI/nutrigenetic diet over 6 months for weight loss and 18-month follow-up

BACKGROUND

Obesity and its related metabolic disturbances represent a huge health burden on society. Many different weight loss interventions have been trialled with mixed efficacy, as demonstrated by the large number of individuals who regain weight upon completion of such interventions. There is evidence that the provision of genetic information may enhance long-term weight loss, either by increasing dietary adherence or through underlying biological mechanisms.

METHODS

The investigators followed 114 overweight and obese subjects from a weight loss clinic in a 2-stage process. 1) A 24-week dietary intervention. The subjects self-selected whether to follow a standardized ketogenic diet (n = 53), or a personalised low-glycemic index (GI) nutrigenetic diet utilising information from 28 single nucleotide polymorphisms (n = 61). 2) After the 24-week diet period, the subjects were monitored for an additional 18 months using standard guidelines for the Keto group vs standard guidelines modified by nutrigenetic advice for the low-Glycaemic Index nutrigenetic diet (lowGI/NG) group.

RESULTS

After 24 weeks, the keto group lost more weight: - 26.2 ± 3.1 kg vs - 23.5 ± 6.4 kg (p = 0.0061). However, at 18-month follow up, the subjects in the low-GI nutrigenetic diet had lost significantly more weight (- 27.5 ± 8.9 kg) than those in the ketogenic diet who had regained some weight (- 19.4 ± 5.0 kg) (p < 0.0001). Additionally, after the 24-week diet and 18-month follow up the low-GI nutrigenetic diet group had significantly greater (p < 0.0001) improvements in total cholesterol (ketogenic - 35.4 ± 32.2 mg/dl; low-GI nutrigenetic - 52.5 ± 24.3 mg/dl), HDL cholesterol (ketogenic + 4.7 ± 4.5 mg/dl; low-GI nutrigenetic + 11.9 ± 4.1 mg/dl), and fasting glucose (ketogenic - 13.7 ± 8.4 mg/dl; low-GI nutrigenetic - 24.7 ± 7.4 mg/dl).

CONCLUSIONS

These findings demonstrate that the ketogenic group experienced enhanced weight loss during the 24-week dietary intervention. However, at 18-month follow up, the personalised nutrition group (lowGI/NG) lost significantly more weight and experienced significantly greater improvements in measures of cholesterol and blood glucose. This suggests that personalising nutrition has the potential to enhance long-term weight loss and changes in cardiometabolic parameters.

TRIAL REGISTRATION

NCT04330209, Registered 01/04/2020, retrospectively registered.

Angiotensin II and leukocyte trafficking: New insights for an old vascular mediator. Role of redox-signaling pathways

Inflammation and activation of the immune system are key molecular and cellular events in the pathogenesis of cardiovascular diseases, including atherosclerosis, hypertension-induced target-organ damage, and abdominal aortic aneurysm. Angiotensin II (Ang-II) is the main effector peptide hormone of the renin-angiotensin system. Beyond its role as a potent vasoconstrictor and regulator of blood pressure and fluid homeostasis, Ang-II is intimately involved in the development of vascular lesions in cardiovascular diseases through the activation of different immune cells. The migration of leukocytes from circulation to the arterial subendothelial space is a crucial immune response in lesion development that is mediated through a sequential and coordinated cascade of leukocyte-endothelial cell adhesive interactions involving an array of cell adhesion molecules present on target leukocytes and endothelial cells and the generation and release of chemoattractants that activate and guide leukocytes to sites of emigration. In this review, we outline the key events of Ang-II participation in the leukocyte recruitment cascade, the underlying mechanisms implicated, and the corresponding redox-signaling pathways. We also address the use of inhibitor drugs targeting the effects of Ang-II in the context of leukocyte infiltration in these cardiovascular pathologies, and examine the clinical data supporting the relevance of blocking Ang-II-induced vascular inflammation.

Genetic and Epigenetic Mechanisms Underlying Vascular Smooth Muscle Cell Phenotypic Modulation in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) refers to the localized dilatation of the infra-renal aorta, in which the diameter exceeds 3.0 cm. Loss of vascular smooth muscle cells, degradation of the extracellular matrix (ECM), vascular inflammation, and oxidative stress are hallmarks of AAA pathogenesis and contribute to the progressive thinning of the media and adventitia of the aortic wall. With increasing AAA diameter, and left untreated, aortic rupture ensues with high mortality. Collective evidence of recent genetic and epigenetic studies has shown that phenotypic modulation of smooth muscle cells (SMCs) towards dedifferentiation and proliferative state, which associate with the ECM remodeling of the vascular wall and accompanied with increased cell senescence and inflammation, is seen in in vitro and in vivo models of the disease. This review critically analyses existing publications on the genetic and epigenetic mechanisms implicated in the complex role of SMCs within the aortic wall in AAA formation and reflects the importance of SMCs plasticity in AAA formation. Although evidence from the wide variety of mouse models is convincing, how this knowledge is applied to human biology needs to be addressed urgently leveraging modern in vitro and in vivo experimental technology.

Effects of the IL6 -174G>C promoter polymorphism and IL-6 serum levels on the progression of cutaneous malignant melanoma

Cutaneous malignant melanoma (CMM) is one of the most immunogenic types of cancer, with a 6-fold higher rate of spontaneous regression than any other malignancy. In addition to responsiveness to different immunotherapies, the immunogenicity of CMM highlights the important role of the host immune system in the response to CMM. The present study aimed to explore the role of two functional promoter polymorphisms [IL6 -174G>C (rs1800785) and TNFA -308G>A (rs1800629)] in the regulation of the genes encoding the pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-α, specifically in patients with CMM. A total of 76 patients with CMM and 200 control subjects were genotyped using PCR-restriction fragment length polymorphism. The genotype frequencies for both single nucleotide polymorphisms (SNPs) did not differ significantly between the patients and controls (P=0.358 and P=0.810 for IL6 and TNFA, respectively). However, compared with carriers of C-allele genotypes (CG+CC), patients with the IL6 -174GG genotype exhibited more advanced melanoma (Clark scale ≥3; P=0.037) and shorter survival times, particularly those who worked outdoors (in conditions with increased sunlight exposure; P=0.016). Furthermore, the serum IL-6 levels of patients with CMM were significantly higher than those of the control subjects, which were associated with unfavorable blood and serum characteristics and tumor progression (development of new distant metastases; P=0.004), and with a shorter overall survival time (P=0.042). Using a Cox proportional hazard model, the IL6 -174GG genotype was found to be an independent prognostic factor for reduced survival time (P=0.030), together with sex (being male; P=0.004) and occupations with higher exposure to sunlight (P=0.047). In conclusion, the results of the present study indicated that the promoter polymorphisms IL6 -174G>C and TNFA -308G>A are not predisposing factors for CMM. However, the IL6 -174G>C SNP and IL-6 serum concentrations are likely to influence the progression of the disease, and the GG genotype and higher IL-6 serum levels may indicate shorter survival.

Itaconate prevents abdominal aortic aneurysm formation through inhibiting inflammation via activation of Nrf2

BACKGROUND

Identifying effective drugs to suppress vascular inflammation is a promising strategy to delay the progression of abdominal aortic aneurysm (AAA). Itaconate has a vital role in regulating inflammatory activation in various inflammatory diseases. However, the role of itaconate in the progression of AAA is unknown. In this study, we explored the inhibitory effect of itaconate on AAA formation and its underlying mechanisms.

METHODS

Quantitative PCR, western blotting and immunohistochemistry were used to determine Irg1 and downstream Nrf2 expression in human and mouse AAA samples. Liquid chromatograph-mass spectrometry (LC-MS) analysis was performed to measure the abundance of itaconate. OI treatment and Irg1 knockdown were performed to study the role of OI in AAA formation. Nrf2 intervention in vivo was performed to detect the critical role of Nrf2 in the beneficial effect of OI on AAA.

FINDINGS

We found that itaconate suppressed the formation of angiotensin II (Ang II)-induced AAA in apolipoprotein E-deficient (Apoe^-/-) mice, while Irg1 deficiency exerted the opposite effect. Mechanistically, itaconate inhibited vascular inflammation by enabling Nrf2 to function as a transcriptional repressor of downstream inflammatory genes via alkylation of Keap1. Moreover, Nrf2 deficiency significantly aggravated inflammatory factor expression and promoted AAA formation. In addition, Keap1 overexpression significantly promoted Ang II-induced AAA formation, which was inhibited by itaconate.

INTERPRETATION

Itaconate inhibited AAA formation by suppressing vascular inflammation, and therapeutic approaches to increase itaconate are potentially beneficial for preventing AAA formation.

FUNDING

National Natural Science Foundations of China and Guangzhou regenerative medicine and Health Laboratory of Guangdong.

Investigating the Contribution of NPSR1, IL-6 and BDNF Polymorphisms to Depressive and Anxiety Symptoms in Hemodialysis Patients

AIMS

Psychological symptoms are prevalent in hemodialysis (HD) patients. Previous investigations showed that brain-derived neurotrophic factor (BDNF) and interleukin-6 (IL-6) as well as the interaction with neuropeptide S receptor 1 (NPSR1) are linked to the development of psychological distress. This study examined the association of polymorphisms of genes encoding these proteins with depression and anxiety in a representative group of Jordanian HD patients.

METHODS

A total of 302 HD patients were involved in the study and categorized into three groups based on the Hospital Anxiety and Depression Scale, HADS-D or HADS-A scores as follows: normal (<7), mild (8-10) and moderate-severe (11-21). Single nucleotide polymorphism (SNP) of NPSR1 Asn107Ile (rs324981), IL-6 G174C (rs1800795), and BDNF Val66Met (rs6265) was genotyped using blood samples.

RESULTS

The frequency of Ile-allele of NPSR1 Asn107Ile was significantly higher in patients with moderate-severe HADS-A scores versus normal (53% vs. 40.8%, p = .035). Using ordinal regression analysis, Asn-allele of NPSR1 polymorphism was nominally significantly associated with a lower risk of anxiety (OR = 0.57, CI: 0.33-0.97, p = .038) after adjusting for other covariates. A marginally significant difference in genotype distribution of IL-6 G174C was observed among patients according to HADS-D scores (p = .05). Furthermore, carriers of IL-6174 CC genotype showed lower median IL-6 serum concentration versus carriers of GG genotype (5.2 vs. 1.35 pg/mL, p < .05).

CONCLUSIONS

The results support the genetic role of NPSR1 in the pathogenesis of anxiety and suggest that carriers of NPSR1 Ile-allele are at increased risk of anxiety in HD patients. Neither BDNF Val66Met nor IL-6 G174C were linked to psychological symptoms. Future studies among other ethnicities are necessary to verify the observations.

A Pilot Study of Protein Microarray for Simultaneous Analysis of 274 Cytokines Between Abdominal Aortic Aneurysm and Normal Aorta

Cytokines play an important role in the pathogenesis of abdominal aortic aneurysm (AAA). We evaluated the cytokine expression profile of large AAA walls using a 274-cytokine protein array. We hypothesized that AAAs are characterized by an inflammatory, chemotactic cytokine profile. We investigated the cytokine expression profile of 12 patients with AAA and 6 nonaneurysmal controls using an antibody-based protein array. The array generated antibodies against homogenized human aortic tissues to validate the cytokines differentially expressed in AAAs and normal aortas. Data were quantified using fluorescent signal intensities and statistically analyzed by the t test. Fifty-nine cytokines were differentially expressed between the AAA and control samples. Of the 35 selected cytokines that had relative expression >1000, 29 were significantly higher and 6 were lower in AAA samples than in controls. They respectively belonged to CC chemokines, CXC chemokines, pro-inflammatory cytokines, growth factors, proteolytic proteins and inhibitors, and cell adhesion cytokines. Our results show that distinct cytokines are involved in AAAs and suggest that the pathways involving these cytokines may be associated with the pathogenesis and development of AAAs. These findings, if confirmed by larger studies, may suggest treatment targets.

Systematic Review of Circulating, Biomechanical, and Genetic Markers for the Prediction of Abdominal Aortic Aneurysm Growth and Rupture

BACKGROUND

The natural course of abdominal aortic aneurysms (AAA) is growth and rupture if left untreated. Numerous markers have been investigated; however, none are broadly acknowledged. Our aim was to identify potential prognostic markers for AAA growth and rupture.

METHODS AND RESULTS

Potential circulating, biomechanical, and genetic markers were studied. A comprehensive search was conducted in PubMed, Embase, and Cochrane Library in February 2017, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Study selection, data extraction, and methodological quality assessment were conducted by 2 independent researchers. Plausibility of markers was based on the amount of publications regarding the marker (more than 3), pooled sample size (more than 100), bias risk and statistical significance of the studies. Eighty-two studies were included, which examined circulating (n=40), biomechanical (n=27), and genetic markers (n=7) and combinations of markers (n=8). Factors with an increased expansion risk included: AAA diameter (9 studies; n=1938; low bias risk), chlamydophila pneumonia (4 studies; n=311; medium bias risk), S-elastin peptides (3 studies; n=205; medium bias risk), fluorodeoxyglucose uptake (3 studies; n=104; medium bias risk), and intraluminal thrombus size (5 studies; n=758; medium bias risk). Factors with an increased rupture risk rupture included: peak wall stress (9 studies; n=579; medium bias risk) and AAA diameter (8 studies; n=354; medium bias risk). No meta-analysis was conducted because of clinical and methodological heterogeneity.

CONCLUSIONS

We identified 5 potential markers with a prognostic value for AAA growth and 2 for rupture. While interpreting these data, one must realize that conclusions are based on small sample sizes and clinical and methodological heterogeneity. Prospective and methodological consonant studies are strongly urged to further study these potential markers.

Embelin inhibits abdominal aortic aneurysm through decreasing IL‑6‑induced STAT3 and NF‑κB inactivation

The aim of the present study was to investigate the effect of embelin on abdominal aortic aneurysm (AAA). AAA model mice were induced by chronic infusion of 1,000 ng/kg/min Angiotensin II. AAA model mice were treated with 25, 50 or 100 mg/kg embelin for 28 days. Embelin inhibited tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6, IL‑18 and malondialdehyde (MDA) level activities, increased superoxide dismutase, glutathione (GSH) and GSH peroxidase level activities and inhibited MDA level activities in AAA mice Embelin suppressed the secretion of matrix metalloproteinase‑9 protein expression, monocyte chemoattractant protein‑2 activity and epithelial neutrophil‑activating peptide expression levels in AAA mice. Embelin suppressed phosphorylated‑signal transducer and activator of transcription (STAT) 3, phosphorylated‑p38 mitogen‑activated protein kinase and nuclear factor (NF)‑κB protein expression in AAA mice. These findings indicate that embelin inhibits AAA through decreasing IL‑6‑induced STAT3, and NF‑κB inactivation.

Sarcopenia is a Significant Predictor of Mortality After Abdominal Aortic Aneurysm Repair

Abstract Background: Repair of abdominal aortic aneurysms (AAA) decreases the incidence of rupture and death. In cancer patients, sarcopenia has been associated with increased surgical complications and mortality. The impact of sarcopenia on survival after AAA repair has yet to be described.    Methods: Patient demographic, laboratory, body composition measurements and survival data were obtained from patients undergoing AAA repair at the Indiana University medical campus over a 5-year period. Univariate and multivariate analyses were performed to identify factors associated with overall survival. Results: Overall, 58.2% presented with sarcopenia. Sarcopenic patients were older (71.8±8.3 versus 66.8±8.1 years; p<0.001), had lower body mass index (BMI) (26.3±5.2 versus 31.5±5.9 kg/m2; p<0.001), higher rates of myosteatosis (84.4% versus 52.%; p<0.001), greater AAA diameter (60.6±14.0 versus 57.8±11.7 mm; p=0.016), higher Charlson Comorbidity Index (CCI) (32.3% versus 25.1% ³6; p=0.034), and increased rates of rupture (8.2% versus 3.8%; p=0.047). Sarcopenic and nonsarcopenic patients had no difference in 30-day morbidity (8.5% versus 8.5%; p=0.991) or mortality (3.7% versus 0.9%; p=0.07). Univariate analysis demonstrated age, sarcopenia, myosteatosis, CCI, and BMI to be associated with long-term survival. There was no correlation between BMI and sarcopenia. Both sarcopenia and myosteatosis resulted in decreased one-, three-, and five-year survivals compared to their counterparts. On multivariate analysis sarcopenia is independently associated with survival, conferring a 1.6-fold increase in death (p=0.04). The combination of sarcopenia plus myosteatosis doubled the risk of death compared to sarcopenia alone. Conclusions: This is the first study to demonstrate that over half of all patients undergoing AAA repair are sarcopenic, a condition associated with increased mortality. Sarcopenia with myosteatosis is associated with double the mortality of sarcopenia alone. CT scan, but not BMI, accurately identifies sarcopenia and myosteatosis. Defining the mechanisms through which sarcopenia contributes to late death after AAA repair is critical to developing novel interventions that may improve survival in this high risk population. 

Prothrombotic State in Asthma Is Related to Increased Levels of Inflammatory Cytokines, IL-6 and TNFα, in Peripheral Blood

Recently, we have reported that asthma is associated with enhanced plasma thrombin formation and impaired fibrinolysis. The mechanisms underlying the prothrombotic state in this disease are unknown. Our aim was to investigate whether prothrombotic alterations in asthmatics are associated with inflammation. We studied 164 adult, white, stable asthmatics and 72 controls matched for age, sex, body mass index (BMI), and smoking. Plasma tumor necrosis factor α (TNFα), interleukin (IL)-6, and serum periostin were evaluated using ELISAs, and their associations with thrombin generation, fibrinolytic capacity, expressed as clot lysis time (CLT), and platelet markers were later analyzed. Asthma was characterized by 62% higher plasma IL-6 and 35% higher TNFα (both, p < 0.0001). Inflammatory cytokines were higher in sporadic and persistent asthmatics compared to controls, also after adjustment for potential confounders. IL-6 was inversely related to the forced expiratory volume in 1 s/vital capacity (FEV₁/VC) spirometry index after correction for age, sex, and BMI. IL-6 and TNFα were associated with C-reactive protein in asthmatics (β = 0.6 [95% CI, 0.54–0.67] and β = 0.33 [95% CI, 0.25–0.41], respectively) and controls (β = 0.43 [95% CI, 0.29–0.57] and β = 0.33 [95% CI, 0.18–0.48], respectively). In asthma, IL-6 and TNFα positively correlated with the endogenous thrombin potential (β = 0.35 [95% CI, 0.28–0.42] and β = 0.15 [95% CI, 0.07–0.23], respectively) but not with CLT or platelet markers. However, TNFα predicted CLT in a multiple linear regression model. Periostin was not associated with any hemostatic parameters. Enhanced thrombin generation is driven in asthma by a systemic inflammatory state mediated by IL-6 and to a lesser extent TNFα, however, not periostin. TNFα might contribute to impaired fibrinolysis.

Molecular targets in aortic aneurysm for establishing novel management paradigms

Aortic aneurysm (AA) is a lethal disease and presents a large challenge for surgeons in the clinic. Although surgical management remains the major choice of AA, operative mortality remains high. With advances in understanding of the mechanisms of AAs, molecular targets, such as matrix metalloproteinases (MMPs), D-dimer, and inflammation markers, including C-reactive protein, interleukins and phagocytes, are important in the pathology of development of AA. These markers may become important for improving the diagnostic quality and provide more therapeutic choices for treatment of AA. Although these new markers require long-term trials before they can be translated into the clinic, they can still be helpful in determining new directions. The main aim of this review is to discuss the current findings of molecular targets in progression of AA and discuss the potential application of these new targets for managing this disease.

Rapamycin inhibits CaCl2-induced thoracic aortic aneurysm formation in rats through mTOR-mediated suppression of proinflammatory mediators

The aim of the present study was to investigate the effect of the mammalian target of rapamycin (mTOR) signaling pathway on thoracic aortic aneurysm (TAA) development. The study used a calcium chloride (CaCl₂)-induced rat TAA model to explore the potential role of mTOR signaling pathway in the disease development. Adult male Sprague-Dawley rats underwent the periarterial exposure of thoracic aorta to either 0.5 M CaCl₂ or normal saline, and a subgroup of CaCl₂-treated rats received rapamycin 1 day prior to surgery. Without pre-administering rapamycin, significantly enhanced phosphorylation of mTOR and expression of proinflammatory cytokines [i.e., tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin (IL)-1β] were observed in the CaCl₂-treated aortic segments 2 days post-treatment compared with the NaCl-treated segments. At 2 weeks post-treatment, hematoxylin and eosin and Verhoeff-Van Gieson staining revealed aneurysmal alteration and disappearance of normal wavy elastic structures in the aortic segments exposed to CaCl₂. In contrast, the CaCl₂-induced TAA formation was inhibited by pre-administering rapamycin to CaCl₂-treated rats, which demonstrated attenuated mTOR phosphorylation and downregulation of the proinflammatory mediators (i.e., TNF-α, IL-6, IL-1β, matrix metallopeptidases 2 and 9) to the control level. Further in vitro cell culture experiments using aortic smooth muscle cell (SMC) suggested that the inhibition of the mTOR signaling pathway by rapamycin could promote the differentiation of SMCs, as reflected by the reduced expression of S100A4 and osteopontin. The present study indicated that the early enhanced mTOR signaling pathway in the TAA development and mTOR inhibitor rapamycin may inhibit CaCl₂-induced TAA formation.

A mathematical model of aortic aneurysm formation

Abdominal aortic aneurysm (AAA) is a localized enlargement of the abdominal aorta, such that the diameter exceeds 3 cm. The natural history of AAA is progressive growth leading to rupture, an event that carries up to 90% risk of mortality. Hence there is a need to predict the growth of the diameter of the aorta based on the diameter of a patient’s aneurysm at initial screening and aided by non-invasive biomarkers. IL-6 is overexpressed in AAA and was suggested as a prognostic marker for the risk in AAA. The present paper develops a mathematical model which relates the growth of the abdominal aorta to the serum concentration of IL-6. Given the initial diameter of the aorta and the serum concentration of IL-6, the model predicts the growth of the diameter at subsequent times. Such a prediction can provide guidance to how closely the patient’s abdominal aorta should be monitored. The mathematical model is represented by a system of partial differential equations taking place in the aortic wall, where the media is assumed to have the constituency of an hyperelastic material.

Interleukin-6 expression on inflamed rat dental pulp tissue after capped with Trigona sp. propolis from south Sulawesi, Indonesia

Background: Propolis is a natural product of plant resins collected by honeybees from various plant sources. It is used as a remedy in folk medicine since ancient times because of its several biological and pharmacological properties. Recently, propolis has been used by dentist to treat various oral diseases. It was always mentioned as an anti-inflammatory agent. Cytokines are proteins that provide communication between cells and play a critical role in a wide variety of processes. It released from cells in an inflammatory process that active, mediate or potential actions of other cells or tissues. When dental pulp has inflammation, several pro-inflammatory cytokines including Interleukin-6 (IL-6) was released by innate immune cells. Objective: To analyse the expression of IL-6 on inflamed rat dental pulp tissue following application of propolis. Material and methods: Trigona sp. propolis was obtained from Luwu Regency, south Sulawesi Province, Indonesia. Flavonoid and non-flavonoid extracts were purified from propolis using thin layer chromatography. The study was applied on 80 male Sprague Dawley rats, 10–12 weeks of age, divided randomly and equally into 5 groups. Group I, as negative control group was not conducted any treatment. At group II, III, IV and V. A Class I cavity (Black Classification) were made on the occlusal surface of right maxillary first molar. The dental pulp was perforated using dental explorer and allowed in the oral environment for 1 h, after that, Ethanolic Extract Propolis (EEP) (Group II), Extract Flavonoid-Propolis (EFP) (Group III), Extract Non-Flavonoid Propolis (ENFP) (Group IV), or Calcium Hydroxide (Ca(OH)₂) (Group V) were applied on dental pulp. All cavities were then filled with Glass Ionomer Cement as permanent filling. The rats being sacrificed in 6 h, 2 days, 4 days and 7 days. Sample biopsy were obtained, IL-6 expression was detected by using immunohistochemistry method. Data was analyzed statistically using Freidman and Kruskal Wallis tests with significance level of P < 0.05. Results: All agent showed IL-6 expression in inflamed rat dental pulp tissue, and this expression was decreased with the longer of observation time periods. EEP more stronger to decreased IL-6 expression on inflamed rat dental pulp tissue than other agent. There is significant difference (P < 0.05) of IL-6 expression between group I and other groups in 6 h and 2 days but not in 4 and 7 days time periods. Conclusion: Trigona sp. propolis from south Sulawesi, Indonesia could suppressed the expression of IL-6 on inflamed rat dental pulp tissue.

The -174G/C Interleukin-6 Gene Promoter Polymorphism as a Genetic Marker of Differences in Therapeutic Response to Methotrexate and Leflunomide in Rheumatoid Arthritis

Objective. To evaluate the association of -174G/C IL-6 polymorphism with failure in therapeutic response to methotrexate (MTX) or leflunomide (LEF). This prospective, observational cohort included 96 Mexican-Mestizo patients with moderate or severe rheumatoid arthritis (RA), initiating MTX or LEF, genotyped for IL-6 -174G/C polymorphism by PCR-RFLP. Therapeutic response was strictly defined: only if patients achieved remission or low disease activity (DAS-28 < 3.2). Results. Patients with MTX or LEF had significant decrement in DAS-28 (p < 0.001); nevertheless, only 14% and 12.5% achieved DAS-28 < 3.2 at 3 and 6 months. After 6 months with any of these drugs the -174G/G genotype carriers (56%) had higher risk of therapeutic failure compared with GC (RR: 1.19, 95% CI: 1.07-1.56). By analyzing each drug separately, after 6 months with LEF, GG genotype confers higher risk of therapeutic failure than GC (RR = 1.56; 95% CI = 1.05-2.3; p = 0.003), or CC (RR = 1.83; 95% CI = 1.07-3.14; p = 0.001). This risk was also observed in the dominant model (RR = 1.33; 95% CI = 1.03-1.72; p = 0.02). Instead, in patients receiving MTX no genotype was predictor of therapeutic failure. We concluded that IL-6 -174G/G genotype confers higher risk of failure in therapeutic response to LEF in Mexicans and if confirmed in other populations this can be used as promissory genetic marker to differentiate risk of therapeutic failure to LEF.

Inflammatory markers and IL-6 polymorphism in peripheral arterial disease with and without diabetes mellitus

Peripheral arterial disease (PAD) is a manifestation of systemic atherosclerosis, recognized as an inflammatory disease of the vessel wall, probably accelerated by diabetes mellitus (DM). Elevated interleukin (IL)-6 levels have been associated with increased cardiovascular morbidity and a common polymorphism has been identified in the promoter region of the IL-6 gene. The aim of this prospective study was to investigate inflammatory mediators in PAD patients (±DM) and to investigate a possible relationship to the IL-6 gene polymorphism. Five groups of patients (DM, intermittent claudication ±DM, critical limb ischemia (CLI) ±DM) and a control group of 20 individuals each were included. Hemoglobin, high sensitive C-reactive protein (hsCRP), creatinine, blood lipids, white blood cells (WBC); CD11b/CD18; vascular cell adhesion molecule (sVCAM-1), intercellular adhesion molecule (sICAM-1), sE-selectin, sP-selectin; IL-6, IL-8, tumour necrosis factor (TNF)α, sTNFα-R1 and sTNFα-R2 were analysed. The IL-6 gene polymorphism was determined in all groups and also compared with 200 healthy controls from a larger study of blood donors. In a multiple regression analysis, adjusted for gender, smoking and age, the effect of CLI was significantly ( p < 0.05) associated with elevated levels of the WBC count, hsCRP, proinflammatory cytokines (IL-6, TNFα-R1-2) and endothelial (sICAM, sVCAM) and WBC (CD11b gran) markers. The effect of less advanced PAD (intermittent claudication) was related to an increased concentration of sVCAM-1 and the number of monocytes and granulocytes. DM or leg ulcers were not significantly related to any of the markers. No significant difference in frequency of the various IL-6 genotypes was found between the groups or when compared with the group of 200 blood donors ( p > 0.3). Activation of cytokines, endothelial cells and WBC was related to the Fontaine stage of PAD but not to the presence of DM or ulcers. No association was found between the polymorphism in the IL-6 promoter region and PAD.

The Genetic Determinants of Renal Impairment Following Cardiac Surgery

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.

Effect of Promoter Polymorphisms on Cytokine Concentration in Preterm Breast Milk and Subsequent Infant Outcomes

BACKGROUND

Breast milk concentrations of immune components are variable between women and interleukin (IL) differences may be associated with infant outcomes. Molecular mechanisms for milk variability remain unknown.

OBJECTIVE

The aims were to (1) examine the relationship between maternal IL genotypes and milk concentrations of IL4, IL6, and IL10, (2) describe the trajectories of milk IL change, (3) examine whether maternal IL genotypes predict IL trajectories and/or average weekly IL concentration, and (4) examine if weekly IL levels and/or IL trajectories are associated with infant outcomes.

METHODS

Milk aliquots were collected from each feeding of mother's own milk and pooled weekly. DNA was extracted from 1 sample of each mother's breast milk whey (n = 64), and single nucleotide polymorphisms (SNPs) of IL genes were genotyped. Milk IL concentrations were measured and trajectory analysis examined IL milk change over time. Multivariate breast milk IL concentration analyses controlled for gestational age and prepregnancy body mass index. Multivariate infant outcome (n = 73) analyses controlled for gestational age and the ratio of human milk to total milk.

RESULTS

Trajectory analysis resulted in linear group shapes, with 2 distinct subgroups in IL6 and 3 subgroups in IL4 and IL10. Trajectory groups trended toward significance with calprotectin, intraventricular hemorrhage, and blood transfusions. Multivariate analyses resulted in trending associations between maternal SNPs and subsequent IL6 and IL10 milk levels. There was a trending relationship between IL milk levels and both fecal calprotectin and intraventricular hemorrhage.

CONCLUSION

Maternal IL SNPs may affect IL breast milk levels and IL milk levels may be associated with infant outcomes.

Circulating interleukin-6 and rheumatoid arthritis: A Mendelian randomization meta-analysis

Interleukin-6 (IL-6), as a pleiotropic cytokine, has been demonstrated to be closely associated with the pathogenisis of rheumatoid arthritis (RA). However, whether this association is causal or not remains unclear, because of the multifactorial role of IL-6 and related confounding factors. We aimed to evaluate the causal relevance between circulating IL-6 levels and the risk of RA through meta-analytical Mendelian randomization approach. IL-6 gene -174G/C variant was selected as an instrument in this Mendelian randomization meta-analysis. Article identification and data collection were conducted in duplicate and independently by 2 authors. The STATA software was used for data analysis. In total, 15 and 5 articles on the association of the -174G/C variant with RA risk and circulating IL-6 level, respectively, were included. The overall analysis showed that C allelic and GC+CC genotype were significantly with 1.59-fold (95% CI: 1.19-2.14) and 1.63-fold (95% CI: 1.17-2.26) increased risk of developing RA, respectively. Asian populations showed stronger association with 4.55-fold (95% CI: 1.62-12.75), 1.84-fold (95% CI: 1.13-2.99), and 4.69-fold (95% CI: 1.68-13.14) increased RA risk in carriers of -174C allelic, CC, and GC+CC genotype, respectively. Carriers of GC+CC genotype showed significant reduction in the circulating IL-6 level compared with GG carriers (WMD = -0.77; 95% CI: -1.16 to -0.38; P = 0.000) in overall populations. Mendelian randomization presented 6% and 22% increased risk of RA with 0.1 pg/mL reduction of circulating IL-6 level in overall and Asian populations, respectively. This Mendelian randomization meta-analysis demonstrated that the long-term genetically reduced circulating IL-6 level might be causally related to a higher risk of RA, especially in Asian populations.

Advanced Glycation End Products and its Soluble Receptors in the Pathogenesis of Thoracic Aortic Aneurysm

BACKGROUND

Matrix metalloproteinases (MMPs) have been implicated in the pathogenesis of thoracic aortic aneurysms (TAAs). Cytokines [Interleukin (IL)-Iβ, IL-2, IL-6, and TNF-α)] increase the expression of MMP-2 and -3. Advanced glycation end products (AGEs) interact with cell receptors to increase the release of cytokines. Circulating soluble receptors for AGEs (sRAGE) and endogenous secretory RAGE (esRAGE) compete with membrane bound RAGE for binding with AGEs and reduce the production of cytokines. It is hypothesized that low levels of serum sRAGE and esRAGE and high levels of AGEs, AGEs/sRAGE, and AGEs/esRAGE would increase the levels of cytokines that would increase the levels MMPs, thus contributing to the formation of TAAs.

METHODS

The study population was composed of 17 control subjects and 20 patients with TAA. Blood samples were collected for measurement of serum sRAGE, esRAGE, AGEs, cytokines, and MMPs. AGEs, sRAGE, and esRAGE were measured using ELISA kits, whereas the remaining parameters were measured using the Luminex Multi-Analyte system.

RESULTS

The levels of sRAGE were lower, while the levels of AGEs, AGEs/sRAGE, AGEs/esRAGE, cytokines and MMPs were higher in patients with TAA compared to controls. The levels of sRAGE were inversely correlated with cytokines and MMPs, while AGEs, AGEs/sRAGE and AGEs/esRAGE were positively correlated with cytokines and MMPs. Cytokines were positively correlated with MMPs.

CONCLUSIONS

The data suggest that the AGE-RAGE axis may be involved in the pathogenesis of TAA and that low levels of sRAGE and high levels of AGEs, AGEs/sRAGE, and AGEs/esRAGE are risk factors for TAA.

C-reactive protein predicts aortic aneurysmal disease progression after endovascular repair

OBJECTIVES

This study aims to investigate the prognostic significance of the rate of variation of C-reactive protein (CRP) levels as a predictor of aneurysmal sac and neck expansion and, therefore, of aneurysm disease progression, in patients undergoing endovascular aneurysm repair (EVAR) in the absence of endoleaks.

METHODS

192 patients following non-emergency elective EVAR for asymptomatic infra-renal abdominal aorta aneurysm (AAA) were included after a six-month period after intervention to ensure the treatment success and absence of endoleaks. Expansion of aneurysm sac or neck after the six-month stabilization term occurred in 120 (63%) and 128 (67%) patients for a mean follow-up of 53±23 months.

RESULTS

The relative CRP plasma level gradient significantly differed between the subgroups of patients according to relative sac expansion quartiles (7%, 26%, 39%, and 61%; p<0.001). In the bivariate analysis, the aorta sac diameter expansion rate progressively increased in the subgroups determined by CRP gradient quartiles (-0.5±1%, 3.6±1%, 8±2%, 10±3%; p<0.01). The median (25th; 75th quartile) CRP level rise in "rapid expanders" patients (those above the median annual sac expansion rate of 5.7%) was 51% (37%; 67%) compared with 15% (3%; 28%) in "slow- or non-expanders" (p<0.001). The multivariate age-adjusted logistic model confirmed the variation of CRP level and neck length as the only factors independently associated to sac expansion (odds ratio 4.3; 95% CI: 2.3-7.9 and 1.7; 95% CI: 1.3-2.2, respectively).

CONCLUSION

There is a significant time-related association between AAA sac diameter enlargement and CRP plasma level gradient after EVAR in the absence of endoleaks, confirming the latter as a proper marker of aneurysm disease progression and rate of expansion in these patients.

Interleukin-6 promoter haplotypes are associated with etanercept response in patients with rheumatoid arthritis

Indices prognosticating anti-tumor necrosis factor (TNF) response in patients with rheumatoid arthritis are a matter of interest. Differential outcome under anti-TNF and anti-interleukin-6 (IL-6) therapy raises the question whether genetic polymorphisms that have previously been linked to IL-6 production are associated with response to anti-TNF therapy. Fifty (50) rheumatoid arthritis (RA) patients were treated with etanercept (median 36 weeks, range 4-52). In terms of the EULAR response criteria, 25 patients responded well, 17 patients moderately and 8 patients not. By direct sequencing, the patients and 91 matched healthy controls were genotyped for the IL-6 promoter SNPs -597G > A (rs1800797), -572G > C (rs1800796) and -174G > C (rs1800795) and for an AnTn microsatellite tract at -373. Alleles and haplotypes were tested for association with disease susceptibility and therapy response. No significant difference was seen in the genotype distribution between patients and healthy controls. Confirming the results of previous studies, we observed a trend of -174G being more frequent in patients with a good or moderate therapy response. Beyond that, carriage of the A9T11 microsatellite allele within the -174G haplotype was associated most closely with a favourable response (relative risk 1.31; 95 % confidence interval 1.02-1.68). A subtle analysis of the IL-6 promoter giving respect to its complex haplotypic structure results in more precise information as to the association of genotypes with the long-term etanercept response. Despite a conclusive hypothesis that a genetically determined IL-6-dominated RA responds less well to anti-TNF, more work has to be done to provide us with reliable information regarding the functional aspects of these genetic polymorphisms.

Influence of Promoter Polymorphisms of the TNF-α (-308G/A) and IL-6 (-174G/C) Genes on Therapeutic Response to Etanercept in Rheumatoid Arthritis

Background

The study was undertaken to assess the influence of functional -308G/A TNF-α (rs 1800629) and -174G/C IL-6 (rs1800795) promoter polymorphisms on the therapeutic response to etanercept, a TNF-α blocker, in patients with rheumatoid arthritis (RA).

Methods

Seventy-three patients suffering from active RA were studied, at baseline and 6 and 12 months after therapy. The therapeutic response was estimated according to the European League Against Rheumatism response criteria. Patients were genotyped for -308G/A TNF-α and -174G/C IL-6 polymorphisms by the PCR-RFLP method, and the influence of genotype on etanercept response was assessed.

Results

No difference in the percentage of responders (patients who had DAS28 improvement > 1.2) between patients with the TNF-α-308GG and GA and AA genotype was detected after 6 and 12 months of treatment. After 12 months of treatment the percentage of responders was significantly increased in patients with the IL-6 -174GG genotype compared with those with the GC or CC genotype (p=0.006 by Chi-square test). Evaluation of the patients according to their combined IL-6/TNF-α genotypes showed that patients with the IL-6 -174GG / TNF-α-308GG genotype were more frequent among the responders compared to those with other combined genotypes (p=0.022 by Chi-square test). More precisely, all patients with the combined IL-6 -174GG / TNF-α-308GG genotype were responders after 12 months of etanercept treatment.

Conclusions

The study suggests that patients who are genetically low TNF-α and IL-6 producers are the best responders to etanercept therapy.

Cyclophilin A in Ruptured Intracranial Aneurysm: A Prognostic Biomarker

Cyclophilin A (CyPA), an oxidative stress-induced factor, was found to play an important role in the aneurysm formation. Our working hypothesis was that the plasma level of CyPA in ruptured intracranial aneurysm could predict the neurological outcome. From 2011 to 2013, a total of 36 patients with ruptured saccular intracranial aneurysm were recruited in our study. Before coil embolization, we draw blood samples at the orifice of a culprit aneurysm and in the remote peripheral vein for measurements of the CyPA levels. We utilized the modified Rankin scale 30 days after aneurysm rupture as the outcome measure. Generalized linear models were used to estimate the adjusted odds ratios of the poor neurological outcome given the presence of high plasma level of CyPA. The aneurysmal and venous CyPA levels were significantly associated with the initial clinical severity (P = 0.004 and 0.03, respectively) and 30-day outcome (P = 0.01 and 0.02, respectively). The aneurysmal CyPA levels modestly correlated with age and high Fisher grade (ρ = 0.39 and 0.41; P = 0.02 and 0.01, respectively). The aneurysmal CyPA levels strongly correlated with the venous counterpart (ρ = 0.89; P < 0.001). Patients with high levels of aneurysmal CyPA were 15.66 times (95% CI, 1.48-166.24; P = 0.02) more likely to have worse neurological outcome than those with the low levels after adjustment of the age, gender, and the documented confounding factors. High plasma level of CyPA is a significant prognostic biomarker for poor neurological outcome in patients with ruptured intracranial aneurysm.

Less Frequent and Less Severe Flu-Like Syndrome in Interferon Beta-1a Treated Multiple Sclerosis Patients with at Least One Allele Bearing the G>C Polymorphism at Position -174 of the IL-6 Promoter Gene

One of the most common adverse event of interferon beta (IFNβ) therapy for multiple sclerosis is flu-like syndrome (FLS), which has been reportedly related to increased levels of cytokines such as interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Average cytokine levels can be affected by single nucleotide polymorphism in the gene promoter regions. To investigate whether IL-6 -174 G>C and TNF-α -376 G>A polymorphisms could be correlated to the incidence of FLS, and whether an anti-inflammatory/antipyretic therapy may influence FLS development, a prospective observational study was performed in 190 treatment naïve, multiple sclerosis patients who started IM IFNβ-1a 30mcg once weekly. The identification of IL-6 -174 G>C and TNF-α -376 G>A polymorphisms was achieved by performing an amplification-refractory mutation system. Serum IL-6 levels were measured using enzyme-linked immunosorbent assay in blood samples taken before therapy and then after the first and last IFNβ-1a injection of the follow-up. FLS-related symptoms were recorded by patients once per week during the first 12 weeks of therapy into a self-reported diary. We found that patients carrying at least one copy of the C allele at position -174 in the promoter of IL-6 gene produced lower levels of IL-6 and were less prone to develop FLS, which was also less severe. On the contrary, the polymorphism of TNF-α had no effect on FLS. Patients taking the first dose of anti-inflammatory/antipyretic therapy in the peri-injection period (within 1 hour) experienced a reduced FLS severity. In conclusion, the study of IL-6 -174 G>C polymorphism would allow the identification of patients lacking the C nucleotide on both alleles who are at risk of a more severe FLS, and may be addressed to a timely and stronger anti-inflammatory/antipyretic therapy for a more effective FLS prevention.

Interleukin-6 as a Prognostic Biomarker in Ruptured Intracranial Aneurysms

BACKGROUND

Interleukin-6 (IL-6), a proinflammatory cytokine, was found to surge in the cerebral spinal fluid after aneurysmal subarachnoid hemorrhage (SAH). We hypothesized that the plasma level of IL-6 could be an independent biomarker in predicting clinical outcome of patients with ruptured intracranial aneurysm.

METHODS

We prospectively included 53 consecutive patients treated with platinum coil embolization of the ruptured intracranial aneurysm. Plasma IL-6 levels were measured in the blood samples at the orifices of the aneurysms and from peripheral veins. The outcome measure was the modified Rankin Scale one month after SAH. Multiple logistic regression analyses were used to evaluate the associations between the plasma IL-6 levels and the neurological outcome.

RESULTS

Significant risk factors for the poor outcome were old age, low Glasgow Coma Scale (GCS) on day 0, high Fisher grades, and high aneurysmal and venous IL-6 levels in univariate analyses. Aneurysmal IL-6 levels showed modest to moderate correlations with GCS on day 0, vasospasm grade and Fisher grade. A strong correlation was found between the aneurysmal and the corresponding venous IL-6 levels (ρ = 0.721; P<0.001). In the multiple logistic regression models, the poor 30-day mRS was significantly associated with high aneurysmal IL-6 level (OR, 17.97; 95% CI, 1.51-214.33; P = 0.022) and marginally associated with high venous IL-6 level (OR, 12.71; 95% CI, 0.90-180.35; P = 0.022) after adjusting for dichotomized age, GCS on day 0, and vasospasm and Fisher grades.

CONCLUSIONS

The plasma level of IL-6 is an independent prognostic biomarker that could be used to aid in the identification of patients at high-risk of poor neurological outcome after rupture of the intracranial aneurysm.