Sustained IFN signaling is associated with delayed development of SARS-CoV-2-specific immunity

Plasma RNAemia, delayed antibody responses and inflammation predict COVID-19 outcomes, but the mechanisms underlying these immunovirological patterns are poorly understood. We profile 782 longitudinal plasma samples from 318 hospitalized patients with COVID-19. Integrated analysis using k-means reveals four patient clusters in a discovery cohort: mechanically ventilated critically-ill cases are subdivided into good prognosis and high-fatality clusters (reproduced in a validation cohort), while non-critical survivors segregate into high and low early antibody responders. Only the high-fatality cluster is enriched for transcriptomic signatures associated with COVID-19 severity, and each cluster has distinct RBD-specific antibody elicitation kinetics. Both critical and non-critical clusters with delayed antibody responses exhibit sustained IFN signatures, which negatively correlate with contemporaneous RBD-specific IgG levels and absolute SARS-CoV-2-specific B and CD4+ T cell frequencies. These data suggest that the "Interferon paradox" previously described in murine LCMV models is operative in COVID-19, with excessive IFN signaling delaying development of adaptive virus-specific immunity.

Emerging role and clinical implication of mRNA scavenger decapping enzyme in colorectal cancer

BACKGROUND

Turnover of RNA is a regulated process that in part controls gene expression. This process is partly controlled by the scavenger decapping enzyme (DcpS). This study aimed to investigate the expression of DcpS in colorectal cancer (CRC) tissue, to evaluate its prognostic significance in patients with CRC and to investigate potentially targeted genes by DcpS.

METHODS

Immunohistochemical analysis was used to determine localization of DcpS in normal and CRC tissue, western blot analysis for quantification of protein expression and qPCR for mRNA expression in normal and CRC tissue and expression in cell lines after silencing using siRNA. Gene array analysis was used to study regulation of genes after silencing of DcpS. Proliferation was studied using BRDU.

RESULTS

DcpS expression was localized to the epithelial cells of both control and cancer tissue. Tumor and paired control tissue samples from 100 patients who underwent surgical resection for primary colorectal adenocarcinomas were utilized. mRNA and protein of DcpS was significantly up-regulated in the patients with CRC and the mRNA level was higher in rectal cancer tissue compared to colon cancer tissue (p < 0.05). Lowest tertile levels of DcpS mRNA in cancer tissue was associated with a decreased cancer-specific survival rate with a hazard ratio (HR) of 4.7 (95% CI=1.02-12.3), independent of disease stage. The low level of DcpS mRNA was a predictor of poorer survival in patients with rectal and disseminated cancer and in patients receiving adjuvant treatment (p < 0.05). After silencing DcpS in Caco-2 cancer cells, altered expression of several genes associated with RNA, cell cycle regulation, alternative splicing and microRNA was observed and resulted in 23% increase in proliferation.

CONCLUSIONS

These results indicate that DcpS has potential as a prognostic factor for CRC but further studies in a broader cohort are warranted to evaluate the significance of the findings in the clinic.

Clinicopathological and prognostic value of CD44 gene polymorphism (rs187115) in Swedish patients with colorectal cancer

Cluster of differentiation (CD) 44 plays a crucial role in apoptosis, cell-cell interactions, angiogenesis, metastasis and proliferation. The aim of the present study was to examine the influence of CD44 gene polymorphism rs187115 on colorectal cancer (CRC) susceptibility and the association with various clinical features including long-term survival in Swedish patients with CRC. Genotypes were screened, using TaqMan single nucleotide polymorphism (SNP) assays based on polymerase chain reaction, in 612 CRC patients and 575 healthy controls.The carriers of G allele, genotypes (AG + GG), were found to be associated with an increased risk of CRC with an odds ratio (OR) of 1.35 (95% confidence interval (CI) = 1.01-1.81; p = 0.039) and found to be more common in patients with mucinous cancer compared with non-mucinous cancer, OR = 1.69 (95% CI = 1.02-2.80; p = 0.011). By using Kaplan-Meier analysis, the patients with genotype GG showed shorter cancer-specific and recurrence free survival with a hazard ratio (HR) of 1.25 (95% CI = 1.02-1.54; p = 0.036) and 1.52 (95% CI = 1.12-2.06; p = 0.007), respectively, in comparison with the carriers of A allele (AG + AA). The present findings demonstrated that the variant G allele of CD44 gene polymorphism rs187115 was related to risk for CRC and associated to mucinous cancer and predict worse prognosis in Swedish patients with CRC.

Effects of diabetes type 2 and metformin treatment in Swedish patients with colorectal cancer

The association between type 2 diabetes mellitus (DM) and colorectal cancer (CRC) has been thoroughly investigated and reports have demonstrated that the risk of CRC is increased in DM patients. The association between DM and the survival of patients with CRC is controversial. Evidence suggests that metformin with its anti-inflammatory effects is a protective factor against the development of CRC among DM patients and that metformin therapy is associated with a better prognosis in patients with DM. In our cohort, we did not find any associations between the presence of DM or metformin and cancer specific survival or any relation to plasma levels of a panel of 40 inflammatory factors and irisin. On the other hand, we identified that the insulin-like growth factor binding protein 7 single nucleotide polymorphism rs2041437 was associated with DM in CRC patients. The dominance of the T bearing genotypes in patients with DM was statistically significant (P = 0.038), with an odds ratio of 1.66 (95% confidence interval: 1.03-2.69).

Association of IL-10 and CRP with Pulse Wave Velocity in Patients with Abdominal Aortic Aneurysm

Background: Markers of inflammation and arterial stiffness are predictors of cardiovascular morbidity and events, but their roles in the mechanisms and progression of abdominal aortic aneurysm (AAA) in males have not been fully investigated. This study explored possible associations between inflammatory marker levels and arterial stiffness in males with AAA. Methods: A total of 270 males (191 AAA and 79 controls) were included in the study. Arterial stiffness was assessed using non-invasive applanation tonometry to measure the regional pulse wave velocity between the carotid and femoral arteries and the carotid and radial arteries. Blood samples were obtained, and interleukin-10 (IL-10) and CRP levels were analysed. Results: Subjects with an AAA had higher levels of IL-10 (21.5 ± 14.0 ng/mL versus 16.6 ± 9.3 ng/mL) compared to controls (p = 0.007). In the AAA cohort, subjects with T2DM showed higher levels of IL-10 (26.4 ± 17.3 versus 20.4 ± 13.0, p = 0.036). We observed a positive correlation between PWVcf and CRP in the control group (r = 0.332) but not the AAA group. PWVcf and CRP were negatively correlated (r = 0.571) in the T2DM subjects treated with metformin in the AAA group. Conclusion: Arterial stiffness is related to the degree of inflammation reflected by CRP and IL-10 levels in males with an AAA. IL-10 is negatively correlated with arterial stiffness in these subjects. This finding suggests that IL-10 may decrease arterial stiffness in males with AAA. The negative correlation between CRP and PWVcf in males with T2DM treated with metformin may indicate that metformin influences the arterial wall to decrease stiffness in subjects with AAA.

miR-10b promotes aortic aneurysm formation and aortic rupture in angiotensin II-induced ApoE-deficient mice

Abdominal aortic aneurysm (AAA) is associated with increased plasma levels of microRNA (miR) -10b. 5 nmols of miR-10b or miR control was administrated to Apolipoprotein E-deficient mice three days prior implantation of osmotic mini-pumps containing angiotensin II, and for three additional times once a week, which increased expression of miR-10b in plasma. Animals receiving miR-10b had a mortality rate due to aortic rupture of 61% compared to 11% in the miR controls (p < 0.05). Further, miR- 10b resulted in an increased aneurysm formation and growth (p < 0.05), which was accompanied by increased elastin degradation, neutrophil and mast cell markers (p < 0.05). In conclusion, miR-10b is functionally affecting aneurysm development and rupture and not only a marker of AAA. More mechanistic studies are required to better understand miR-10b's role in AAA formation.

Circulating microRNA in patients with popliteal and multiple artery aneurysms

Background

Patients with popliteal artery aneurysm (PA) often have multiple aneurysms, such as bilateral disease or a concomitant abdominal aortic aneurysm (AAA). microRNAs (miRs) are regulators of biological processes and have been investigated as biomarkers for AAA. The aim of this study was to explore if the presence of multiple aneurysms and/or location correlated with miR levels in blood.

Methods

Using quantitative polymerase chain reaction, 23 miRs were analyzed in plasma from 183 patients with PA.

Results

Fifteen of the miRs were associated with the number and/or location of aneurysms (1.3- to 2.1-fold changes). Levels of miR-93 (1.4-fold) and miR-215 (1.6- to 1.9-fold) were changed in all compared groups. MiR-24 and miR-23a were altered in those with AAA (1.4- and 1.5-fold, respectively) or bilateral PA (1.5- and 1.4-fold, respectively), compared with in those without. MiR-145 were significantly altered (1.7-fold) in those with isolated PA and AAA, whereas miR-326 were altered in those with bilateral (2.3-fold) and isolated PA (1.9-fold).

Conclusions

Different miRs seem to be important or to be markers for different subgroups of patients with PA. The identified miRs target vascular smooth muscle cell proliferation and vascular inflammation. Further studies are needed to increase the understanding of the pathogenesis of aneurysmal disease.

Patients with popliteal artery aneurysm often have multiple aneurysms, such as bilateral disease or concomitant abdominal aortic aneurysms, but the molecular pathogenesis of the disease is not fully understood. MicroRNAs are important regulators of gene expression and biological processes and have recently been investigated as possible biomarkers for abdominal aortic aneurysm. This study identified 11 microRNAs that were altered in subgroups of patients with popliteal artery aneurysm, which could be important regulators to study in interventional studies.

Inhibition of angiotensin-induced aortic aneurysm by metformin in apolipoprotein E-deficient mice

Objective

Metformin is associated with a reduced incidence and growth of abdominal aortic aneurysms (AAAs). The aim of the present study was to investigate the inhibitory effects of metformin on AAA development and possible underlying mechanisms in experimentally induced AAAs in mice, along with the possible synergistic effects of metformin and imatinib.

Methods

Angiotensin II was used to induce AAAs in apolipoprotein E knockout (ApoE ^-/- ) mice for 28 days. The mice were treated with metformin (n = 11), metformin combined with imatinib (n = 7), or vehicle (n = 12), starting 3 days before angiotensin II infusion. Ultrasound examination was used to analyze aneurysm formation. Cholesterol and blood pressure levels were measured at the start and end of the study. Gene array and quantitative polymerase chain reaction were used to analyze the changes in gene expression in the aorta. Wire myography was used to study vascular function.

Results

Metformin (n = 11) suppressed the formation and progression of AAAs by 50% compared with the vehicle controls (n = 12), with no further effects from imatinib (n = 7). Metformin reduced total cholesterol and mRNA expression of SPP1 (encoding osteopontin), MMP12, and the glycoprotein genes Gpnmb and Clec7a. Furthermore, metformin inhibited blood pressure increases and reduced vascular contractions, as determined by wire myography, and restored the anticontractile function of perivascular adipose tissue.

Conclusion

Metformin inhibited aneurysm formation and progression and normalized vascular function in ApoE ^-/- mice with no additional effect of imatinib. This might be mediated by the protective effects on vascular endothelial function and perivascular adipose tissue via reduced expression of genes promoting inflammation, including SPP1, MMP12, Gpnmb, and Clec7a.

Clinical relevance

Retrospective studies of the effects of metformin in patients with aneurysm have so far only been performed of those with type 2 diabetes. The present study shows that metformin has effects on nondiabetic mice and revealed the mechanistic effects mediated by the drug that could also be important to study as outcomes in humans. Future clinical trials using metformin are warranted in patients without diabetes with abdominal aortic aneurysms.

A histopathological classification scheme for abdominal aortic aneurysm disease

OBJECTIVE

Two consensus histopathological classifications for thoracic aortic aneurysms (TAAs) and inflammatory aortic diseases have been issued to facilitate clinical decision-making and inter-study comparison. However, these consensus classifications do not specifically encompass abdominal aortic aneurysms (AAAs). Given its high prevalence and the existing profound pathophysiologic knowledge gaps, extension of the consensus classification scheme to AAAs would be highly instrumental. The aim of this study was to test the applicability of, and if necessary to adapt, the issued consensus classification schemes for AAAs.

METHODS

Seventy-two AAA anterolateral wall samples were collected during elective and emergency open aneurysm repair performed between 2002 and 2013. Histologic analysis (hematoxylin and eosin and Movat Pentachrome) and (semi-quantitative and qualitative) grading were performed in order to map the histological aspects of AAA. Immunohistochemistry was performed for visualization of aspects of the adaptive and innate immune system, and for a more detailed analysis of atherosclerotic lesions in AAA.

RESULTS

Because the existing consensus classification schemes do not adequately capture the aspects of AAA disease, an AAA-specific 11-point histopathological consensus classification was devised. Systematic application of this classification indicated several universal features for AAA (eg, [almost] complete elastolysis), but considerable variation for other aspects (eg, inflammation and atherosclerotic lesions).

CONCLUSIONS

This first multiparameter histopathological AAA consensus classification illustrates the sharp histological contrasts between thoracic and abdominal aneurysms. The value of the proposed scoring system for AAA disease is illustrated by its discriminatory capacity to identify samples from patients with a nonclassical (genetic) variant of AAA disease.

Parallel Murine and Human Aortic Wall Genomics Reveals Metabolic Reprogramming as Key Driver of Abdominal Aortic Aneurysm Progression

Background While numerous interventions effectively interfered with abdominal aortic aneurysm (AAA) formation/progression in preclinical models, none of the successes translated into clinical success. Hence, a systematic exploration of parallel and divergent processes in clinical AAA disease and its 2 primary models (the porcine pancreatic elastase and angiotensin-II infusion [AngII] murine model) was performed to identify mechanisms relevant for aneurysm disease. Methods and Results This study combines Movat staining and pathway analysis for histological and genomic comparisons between clinical disease and its models. The impact of a notable genomic signal for metabolic reprogramming was tested in a rescue trial (AngII model) evaluating the impact of 1-(4-pyridinyl)-3-(2-quinolinyl)-2-propen-1-one (PFK15)-mediated interference with main glycolytic switch PFKFB3. Histological evaluation characterized the AngII model as a dissection model that is accompanied by adventitial fibrosis. The porcine pancreatic elastase model showed a transient inflammatory response and aortic dilatation, followed by stabilization and fibrosis. Normalization of the genomic responses at day 14 confirmed the self-limiting nature of the porcine pancreatic elastase model. Clear parallel genomic responses with activated adaptive immune responses, and particularly strong signals for metabolic switching were observed in human AAA and the AngII model. Rescue intervention with the glycolysis inhibitor PFK15 in the AngII model showed that interference with the glycolytic switching quenches aneurysm formation. Conclusions Despite clear morphological contrasts, remarkable genomic parallels exist for clinical AAA disease and the AngII model. The metabolic response appears causatively involved in AAA progression and provides a novel therapeutic target. The clear transient genomic response classifies the porcine pancreatic elastase model as a disease initiation model.

Association of gene and protein expression and genetic polymorphism of CC chemokine ligand 4 in colorectal cancer

BACKGROUND

Leukocytes, such as T cells and macrophages, play an important role in tumorigenesis. CC chemokine ligand (CCL) 4, which is produced by lymphocytes and macrophages, has been found to be expressed in the mucosa of the gastrointestinal tract and is a potent chemoattractant for various leukocytes.

AIM

To examine CCL4 expression and its genetic polymorphism rs10491121 in patients with colorectal cancer (CRC) and evaluate their prognostic significance.

METHODS

Luminex technology was used to determine CCL4 Levels in CRC tissue (n = 98), compared with paired normal tissue, and in plasma from patients with CRC (n = 103), compared with healthy controls (n = 97). Included patients had undergone surgical resection for primary colorectal adenocarcinomas between 1996 and 2019 at the Department of Surgery, Ryhov County Hospital, Jönköping, Sweden. Reverse transcription quantitative PCR was used to investigate the CCL4 gene expression in CRC tissue (n = 101). Paired normal tissue and TaqMan single nucleotide polymorphism assays were used for the CCL4 rs10491121 polymorphism in 610 CRC patients and 409 healthy controls.

RESULTS

The CCL4 protein and messenger RNA expression levels were higher in CRC tissue than in normal paired tissue (90%, P < 0.001 and 45%, P < 0.05, respectively). CRC tissue from patients with localized disease had 2.8-fold higher protein expression levels than that from patients with disseminated disease. Low CCL4 protein expression levels in CRC tissue were associated with a 30% lower cancer-specific survival rate in patients (P < 0.01). The level of plasma CCL4 was 11% higher in CRC patients than in healthy controls (P < 0.05) and was positively correlated (r = 0.56, P < 0.01) with the CCL4 protein level in CRC tissue. The analysis of CCL4 gene polymorphism rs10491121 showed a difference (P < 0.05) between localized disease and disseminated disease in the right colon, with a dominance of allele A in localized disease. Moreover, the rate of the A allele was higher among CRC patients with mucinous cancer than among those with non-mucinous cancer.

CONCLUSION

The present study indicates that the CRC tissue levels of CCL4 and CCL4 gene polymorphism rs10491121, particularly in the right colon, are associated with clinical outcome in CRC patients.

Circulating microRNA-29-5p can add to the discrimination between dilated cardiomyopathy and ischaemic heart disease

Aims

Heart failure describes a large and heterogeneous spectrum of underlying cardiac diseases. MicroRNAs (miRs) are small non‐coding RNAs that in recent years have been shown to play an important role in the pathogenesis of heart failure. Cardiac magnetic resonance imaging is a powerful imaging modality for the evaluation of cardiac characteristics in heart failure. In this study, we sought to compare heart failure patients with a diagnosis of either idiopathic dilated cardiomyopathy (DCM) or ischaemic heart disease (IHD), in the context of serum levels of certain miRs and also magnetic resonance imaging parameters of cardiac structure and function.

Methods and results

A total of 135 subjects were studied: 53 patients with DCM (age: 59 ± 12 years, mean ± SD), 34 patients with IHD (66 ± 9 years), and 48 controls (64 ± 5 years). The participants underwent baseline medical examination, blood sampling, and a cardiac magnetic resonance imaging examination at 3 Tesla (Philips Ingenia). The serum levels of seven different miRs were analysed and assessed: 16‐5p, 21‐5p, 29‐5p, 133a‐3p, 191‐5p, 320a, and 423‐5p, all of which have been demonstrated to play potential roles in the pathogenesis of heart failure.

The patients in the DCM and IHD groups had left ventricles that had larger end‐diastolic volume (P < 0.001), larger mass (P < 0.001), and lower ejection fraction (P < 0.001) compared with controls. Serum levels of miR‐29‐5p were increased in DCM compared with IHD (P < 0.005) and serum levels of miR‐320a were elevated in DCM compared with healthy controls (P < 0.05). There was no significant association between miR levels and magnetic resonance imaging parameters of left ventricular structure and function.

Conclusions

Circulating miR‐320a can add to the discrimination between patients with DCM and healthy controls and circulating miR‐29‐5p can add to the discrimination between DCM and IHD.

Increased mortality in the A/A genotype of the SNP rs28372698 of interleukin 32

One of the major causes of mortality in the western hemisphere is cardiovascular disease. Therefore, a variety of markers to identify those at risk are required. Interleukin-32 (IL-32) is a cytokine that is associated with inflammation. The aim of the current study was to investigate variations in single nucleotide polymorphisms (SNPs) of IL-32 and plasma expression, and their associations with mortality. A population of 486 elderly community-living persons were evaluated. The participants were followed for 7.1 years and underwent a clinical examination and blood sampling. SNP analyses of IL-32 rs28372698 using allelic discrimination and plasma measurement of IL-32, using ELISA, were performed. During the follow-up period, 140 (28.8%) all-cause and 87 (17.9%) cardiovascular deaths were registered. No significant difference between mortality and plasma concentration of IL-32 was observed. The A/A genotype group exhibited significantly higher all-cause mortality (P=0.036), and an almost two-fold increased risk in a multivariate Cox regression model for all-cause and cardiovascular mortality. A highly significant difference in all-cause and cardiovascular mortality between the A/A and the T/T groups was demonstrated (P=0.015 resp. P=0.014). In the present study, the cytokine IL-32 was demonstrated to have prognostic information, with an increased risk of all-cause and cardiovascular mortality for those with the A/A genotype rs28372698 of IL-32. The A/A genotype could therefore be regarded as a possible biomarker for mortality risk that may be used to offer optimized cardiovascular patient handling in the future. However, the present study sample was small, and the results should be regarded as hypothesis-generating.

Genetic variance and plasma concentration of CD93 is associated with cardiovascular mortality: Results from a 6.7‑year follow‑up of a healthy community‑living elderly population

Inflammation is one of the fundamental processes in numerous diseases. Cluster of differentiation (CD) 93, a glycoprotein, has been reported to be associated with a number of these diseases. There are reports indicating that a high plasma level of CD93 is associated with adverse events in ischaemic heart disease. Additionally, there are reports indicating different cardiovascular risks between different single nucleotide polymorphisms (SNPs) of CD93. Therefore, the present study aimed to determine whether the plasma concentration of CD93 and polymorphism of rs2749812 in CD93 were associated with clinical conditions and mortality in an elderly population. In 470 healthy elderly community-living individuals a novel clinical examination involving echocardiography and blood sampling was performed. The population was followed for 6.7 years. Plasma levels of CD93 and SNP analyses of rs2749812 of CD93 using PCR methodology were used. During the follow-up period, 106 (22.6%) all-cause and 61 (13.0%) cardiovascular deaths were registered. Those with the highest plasma concentration had markedly higher all-cause mortality. Evaluating the A/A, A/G and G/G genotypes, the G/G group exhibited significantly higher cardiovascular mortality (P=0.026), and an almost two-fold increased risk in a multivariate Cox regression model compared with the A/G genotype. Evaluation of subgroups with respect to sex, diabetes and hypertension revealed markedly increased cardiovascular risk in the G/G genotype in all subgroups. All results persisted in the multiple models used. In the present study, the glycoprotein CD93 was demonstrated to have prognostic cardiovascular information, with increased risk for those with a high plasma concentration. Furthermore, the G/G genotype of rs2749812 of CD93 has a significantly higher cardiovascular risk, as demonstrated here, and could therefore be regarded as a possible cardiovascular risk biomarker that might in the future be used to offer optimised cardiovascular patient handling. However, this was a small study, and more research is required.

Increased cardiovascular mortality in females with the a/a genotype of the SNPs rs1478604 and rs2228262 of thrombospondin-1

BACKGROUND

Cardiovascular diseases are still the major cause of death in the Western world, with different outcomes between the two genders. Efforts to identify those at risk are therefore given priority in the handling of health resources. Thrombospondins (TSP) are extracellular matrix proteins associated with cardiovascular diseases. The aim of this study was to investigate variations in single nucleotide polymorphisms (SNPs) of TSP-1 and plasma expression, and associations with mortality from a gender perspective.

METHODS

A population of 470 community-living persons were invited to participate. The participants were followed for 7.9 years and underwent a clinical examination and blood sampling. SNP analyses of TSP-1 rs1478604 and rs2228262 using allelic discrimination and plasma measurement of TSP-1 using ELISA were performed, RESULTS: During the follow-up period, 135 (28.7%) all-cause and 83 (17.7%) cardiovascular deaths were registered. In the female population, the A/A genotype of rs2228262 and the T/T genotype of rs1478604 exhibited significantly more cardiovascular deaths compared with the A/G and G/G, or the T/C and C/C genotypes amalgamated (rs2228262: 13.7% vs 2.0%; Χ²:5.29; P = 0.02; rs1478604:17.7% vs 4.7%; Χ²:9.50; P = 0.002). Applied in a risk evaluation, the A/A, or T/T genotypes exhibited an increased risk of cardiovascular mortality (rs2228262: HR: 7.1; 95%CI 1.11-45.8; P = 0.04; rs1478604: HR: 3.18; 95%CI 1.35-7.50; p = 0.008). No differences among the three genotypes could be seen in the male group.

CONCLUSION

In this study the female group having the A/A genotype of rs2228262, or the T/T genotype of rs1478604 of TSP-1 exhibited higher cardiovascular mortality after a follow-up of almost 8 years. No corresponding genotype differences could be found in the male group. Genotype evaluations should be considered as one of the options to identify individuals at risk. However, this study should be regarded as hypothesis-generating, and more research in the field is needed.

Metformin Prescription Associated with Reduced Abdominal Aortic Aneurysm Growth Rate and Reduced Chemokine Expression in a Swedish Cohort

BACKGROUND

Recent reports suggest that the negative association between diabetes mellitus and abdominal aortic aneurysm (AAA) may be driven by metformin, the world's most common antidiabetic drug rather than diabetes per se. We sought to investigate the association among AAA growth rate, chemokine profile, and metformin prescription in a contemporary Swedish cohort.

METHODS

Patients under surveillance for small AAA were identified at 4 Swedish vascular centers with active AAA screening programs. Annual AAA growth rate, medical history, and prescribed medications were recorded for linear regression analysis. In a subset of patients with AAA and control subjects without AAA or diabetes, plasma samples were available and analyzed for 40 inflammatory chemokines.

RESULTS

A total of 526 patients were included for AAA growth analysis: 428 without type 2 diabetes mellitus (T2DM), 65 with T2DM and metformin prescription, and 33 with T2DM but without metformin prescription. Patients were included from 2005 to 2017 with mean follow-up of 3.2 (1.7) years and median annual AAA growth rate 1.6 mm, range -4.8 to 15.4 mm. Mean (standard deviation) annual AAA growth rates were 2.3 (2.2) mm in non-T2DM patients versus 1.1 (1.1) mm in patients with T2DM with metformin prescription and 1.6 (1.4) mm among those with T2DM without metformin prescription. With non-T2DM patients as reference in an unadjusted and 2 adjusted models, metformin prescription was significantly associated with reduced AAA growth rate (P < 0.001, P = 0.005, and P = 0.024, respectively), but not T2DM without metformin prescription (P = 0.137, P = 0.331, and P = 0.479, respectively). Among 240 patients with AAA (152 without T2DM, 51 with T2DM and metformin, and 37 with T2DM without metformin) and 59 without AAA or T2DM, metformin prescription was associated with reduced expression of chemokines representing all classes of leukocytes.

CONCLUSIONS

Metformin prescription is associated with reduced AAA growth rate, possibly mediated by broad anti-inflammatory effects. A randomized controlled trial is needed to determine what role metformin may play in AAA disease, particularly in the absence of T2DM.

Altered IL-32 Signaling in Abdominal Aortic Aneurysm

INTRODUCTION AND OBJECTIVE

Interleukin (IL)-32 is a pro-inflammatory cytokine not previously studied in relation to abdominal aortic aneurysm (AAA). The aim of this study was to elucidate the expression and localization of IL-32 in AAA.

METHODS

Expression and localization of IL-32 in human aortic tissue was studied with immunohistochemical analysis and Western blot (AAA: n = 5; controls: n = 4). ELISA was used to measure IL-32 in human plasma samples (AAA: n = 140; controls: n = 37) and in media from cultured peripheral blood mononuclear cells (PBMCs) from 3 healthy donors. IL-32 mRNA in PBMCs, endothelial cells, aortic smooth muscle cells (SMCs), and aortic tissue samples of AAA (n = 16) and control aortas (n = 9) was measured with qPCR.

RESULTS

IL-32 was predominantly expressed in SMCs and T-cell-rich areas. Highest mRNA expression was observed in the intima/media layer of the AAA. A weaker protein expression was detected in non-aneurysmal aortas. Expression of IL-32 was confirmed in isolated T cells, macrophages, endothelial cells, and SMCs, where expression was also inducible by cytokines such as interferon-γ. There was no difference in IL-32 expression in plasma between patients and controls.

CONCLUSION

IL-32 signaling is altered locally in AAA and could potentially play an important role in aneurysm development. Further studies using animal models would be helpful to study its potential role in AAA disease.

Gender difference and genetic variance in lipoprotein receptor-related protein 1 is associated with mortality

Cardiovascular diseases are an important health resource problem and studies have shown a genetic association between single nucleotide polymorphisms (SNPs) and cardiovascular diseases. According to the literature, lipoprotein receptor-related protein 1 (LRP1) is associated with coronary artery disease. The aim of the present study was to evaluate a possible association between different genotypes of LRP1 and all-cause and cardiovascular mortality from a gender perspective. In the present study, 489 elderly community-living people were invited to participate. Clinical examination, echocardiography and blood sampling including SNP analyses of LRP1 (rs1466535) were performed, including the T/T, C/T and C/C genotypes, and the participants were followed for 6.7 years. During the follow-up period, 116 (24%) all-cause and 75 (15%) cardiovascular deaths were registered. In the female population, the LRP1 of the T/T or C/T genotype exhibited a 5.6-fold increased risk of cardiovascular mortality and a 2.8-fold increased risk of all-cause mortality compared with the C/C genotype. No such genotype differences could be seen in the male population. Gender differences could be seen regarding the risk of mortality in the different genotypes. Females with the LRP1 T/T or C/T genotypes exhibited a significantly increased risk of both all-cause and cardiovascular mortality compared with the C/C genotypes. Therefore, more individualized cardiovascular prevention and treatment should be prioritized. However, since this was a small study, the observations should only be regarded as hypothesis-generating.

Possible Role and Therapeutic Target of PDGF-D Signalling in Colorectal Cancer

Platelet-derived growth factor D (PDGF-D) has been shown to mediate cellular processes of importance in cancer progression. This study aimed to investigate the expression and putative involvement of PDGF-D signaling in colorectal carcinogenesis. PDGF-D was expressed in vascular endothelial cells in tumor and normal tissues. PDGF-D stimulation of cells altered genes of importance in carcinogenic processes. In addition, PDGF-D increased the proliferation rate while imatinib inhibited these effects. PDGF-D and its PDGF receptor beta (PDGFR-β) are expressed in colorectal cancer and blockage of PDGF-D/PDGFR-β signaling using tyrosine kinase inhibitors, such as imatinib, might be important in inhibiting tumor-promoting actions.

Effects of osteoprotegerin/TNFRSF11B in two models of abdominal aortic aneurysms

Osteoprotegerin (OPG), additionally termed tumor necrosis factor receptor superfamily member 11B, is produced by vascular smooth muscle cells (VSMCs) and endothelial cells in the vasculature, and its release may be modulated by pro-inflammatory cytokines, including interleukin-1β and tumor necrosis factor-α. The present study investigated the effects of treatment with low-dose human recombinant OPG on abdominal aortic aneurysm (AAA) development in mice. Mice were treated with 1 µg human recombinant OPG four times (or vehicle) for 2 weeks prior to inducing AAA. A total of two different models for inducing AAA were used to investigate the hypothesis as to whether OPG is involved in key events of AAA development, using osmotic mini-pumps with angiotensin II in apolipoprotein-E (ApoE^−/−) mice for 28 days or using periaortic application of CaCl₂ on the aorta in C57Bl/6J mice for 14 days. OPG was continuously administered during the experimental period. Histological staining using Masson's trichrome, Verhoeff's van-Gieson and picro-sirius red, in addition to reverse transcription-quantitative polymerase chain reaction analysis of various markers, were used to analyze phenotypic alterations. Treatment with OPG had no inhibitory effect on AAA development in the angiotensin II model in ApoE^−/− mice, which developed suprarenal aneurysms, although it increased vessel wall thickness of the aorta and total collagen in C57Bl/6J mice using the CaCl₂ model that induced infrarenal dilation of the aorta. Treatment with OPG did not inhibit aneurysm development and key events, including inflammation, extracellular matrix or VSMC remodeling, in aortas from OPG-treated mice with periaortic treatment with CaCl₂. The results indicated that mice treated with low levels of human recombinant OPG may have a more stable aneurysmal phenotype due to compensatory production of collagen and increased vessel wall thickness of the aorta, potentially protecting the aneurysm from rupture. Further studies investigating rupture models of AAA in addition to using higher levels of OPG are require to verify this speculation. Furthermore, treatment with low levels of OPG in patients with AAA may represent a novel therapeutic strategy for the treatment of AAA as well as attenuate the adverse effects associated with the administration of normal and high dosages of OPG.

Plasma cholesterol lowering in an AngII‑infused atherosclerotic mouse model with moderate hypercholesterolemia

Atherosclerosis is the main underlying causes of cardiovascular disease. There is a well‑established association between high blood cholesterol levels and the extent of atherosclerosis. Furthermore, atherosclerosis has been proposed to augment abdominal aortic aneurysm (AAA) formation. As patients with AAA often have parallel atherosclerotic disease and are therefore often on cholesterol‑lowering therapy, it is not possible to fully address the independent effects of plasma cholesterol lowering (PCL) treatment on AAA. The present study investigated the effect of angiotensin II (AngII)‑infusion in modestly hypercholesterolemic Ldlr‑/‑Apob100/100Mttpflox/floxMx1‑Cre mice with or without PCL treatment on a morphological and molecular level, in terms of atherosclerosis and AAA development. AngII infusion in the study mice resulted in an increased atherosclerotic lesion area and increased infiltration of inflammatory leukocytes, which was not observed in mice with PCL induced prior to AngII infusion. This suggested that AngII infusion in this mouse model induced atherosclerosis development, and that plasma cholesterol levels represent a controlling factor. Furthermore, AngII infusion in Ldlr‑/‑Apob100/100Mttpflox/floxMx1‑Cre mice caused a modest aneurysmal phenotype, and no differences in AAA development were observed between the different study groups. However, the fact that modest hypercholesterolemic mice did not develop AAA in a classical aneurysmal model indicated that plasma cholesterol levels are important for disease development.

PDGF-C and PDGF-D signaling in vascular diseases and animal models

Members of the platelet-derived growth factor (PDGF) family are well known to be involved in different pathological conditions. The cellular and molecular mechanisms induced by the PDGF signaling have been well studied. Nevertheless, there is much more to discover about their functions and some important questions to be answered. This review summarizes the known roles of two of the PDGFs, PDGF-C and PDGF-D, in vascular diseases. There are clear implications for these growth factors in several vascular diseases, such as atherosclerosis and stroke. The PDGF receptors are broadly expressed in the cardiovascular system in cells such as fibroblasts, smooth muscle cells and pericytes. Altered expression of the receptors and the ligands have been found in various cardiovascular diseases and current studies have shown important implications of PDGF-C and PDGF-D signaling in fibrosis, neovascularization, atherosclerosis and restenosis.

Circulating inflammatory factors associated with worse long-term prognosis in colorectal cancer

AIM

To investigate association of circulating inflammatory factors at the time of colorectal cancer (CRC) surgery with survival.

METHODS

Plasma levels from 174 CRC patients (69 females and 105 men), with median age 70 years (range 29-90), localized in the colon (n = 105) or rectum (n = 69), with stage I (n = 24), stage II (n = 54), stage III (n = 67) and stage IV (n = 29) were measured using commercially available Bio-Plex Pro™ Human Chemokine Panel 40-Plex, including 40 different chemokines, cytokines and interleukins. The prognostic association of each inflammatory factor was analysed as CRC-specific and total mortality.

RESULTS

Out of 174 patients, 66 died during the follow-up, 40 because of CRC specific mortality. High tertile levels of 8 factors were significantly associated with increased CRC-specific mortality, of which CCL1, CCL20, CCL24, CX3CL1, IL-4 and TNF-α remained significant in a multivariate Cox regression analysis. High tertile levels of 14 factors were associated with increased total mortality, of which CCL1, CCL15, CCL20, CX3CL1, CXCL13, IFN-γ, IL-2, IL-4 and IL-10 remained significant after adjustment for clinical covariates. For most of the inflammatory factors the association between higher tertile levels and an increased mortality in general appeared two years after surgery. High tertile levels of TNF-α and CCL24 were exclusively associated with CRC-specific mortality. The distribution of these factors were not associated with TNM stage with exception for CCL20.

CONCLUSION

High plasma levels of inflammatory factors are associated with increased risk of mortality among CRC patients and could be potential biomarkers for revealing prognosis.

ADAMTS-1 in abdominal aortic aneurysm

Introduction

Extracellular matrix degradation is a hallmark of abdominal aortic aneurysm (AAA). Among proteases that are capable of degrading extracellular matrix are a disintegrin and metalloproteases with thrombospondin motifs (ADAMTS). Pathogenesis of these proteases in AAA has not been investigated until date.

Methods and results

Human aneurysmal and control aortas were collected and analyzed with RT-PCR measuring the ADAMTS-1, 4,5,6,8,9,10,13,17 and ADAMTSL-1. Expression of a majority of the investigated ADAMTS members on mRNA level was decreased in aneurysm compared to control aorta. ADAMTS-1 was one of the members that was reduced most. Protein analysis using immunohistochemistry and western blot for localization and expression of ADAMTS-1 revealed that ADAMTS-1 was present predominantly in areas of SMCs and macrophages in aneurysmal aorta and higher expressed in AAA compared to control aortas. The role of ADAMTS-1 in AAA disease was further examined using ADAMTS-1 transgenic/apoE^-/- mice with the experimental angiotensin II induced aneurysmal model. Transgenic mice overexpressing ADAMTS-1 showed to be similar to ADAMTS-1 wild type mice pertaining collagen, elastin content and aortic diameter.

Conclusion

Several of the ADAMTS members, and especially ADAMTS-1, are down regulated at mRNA level in AAA, due to unknown mechanisms, at the same time ADAMTS-1 protein is induced. The cleavage of its substrates, don’t seem to be crucial for the pathogenesis of AAA but rather more important in the development of thoracic aortic aneurysm and atherosclerosis as shown in previous studies.

Significant changes in circulating microRNA by dietary supplementation of selenium and coenzyme Q10 in healthy elderly males. A subgroup analysis of a prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens

Background

Selenium and coenzyme Q10 is essential for important cellular functions. A low selenium intake is reported from many European countries, and the endogenous coenzyme Q10 production is decreasing in the body with increasing age. Supplementation with selenium and coenzyme Q10 in elderly have shown reduced cardiovascular mortality and reduced levels of markers of inflammation. However, microRNA analyses could give important information on the mechanisms behind the clinical effects of supplementation.

Methods

Out of the 443 healthy elderly participants that were given supplementation with 200 μg Se/day as organic selenium yeast tablets, and 200 mg/day of coenzyme Q10 capsules, or placebo for 4 years, 25 participants from each group were randomized and evaluated regarding levels of microRNA. Isolation of RNA from plasma samples and quantitative PCR analysis were performed. Volcano- and principal component analyses (PCA)–plots were used to illustrate the differences in microRNA expression between the intervention, and the placebo groups. Serum selenium concentrations were measured before intervention.

Findings

On average 145 different microRNAs out of 172 were detected per sample. In the PCA plots two clusters could be identified indicating significant difference in microRNA expression between the two groups. The pre-treatment expression of the microRNAs did not differ between active treatment and the placebo groups. When comparing the post-treatment microRNAs in the active and the placebo groups, 70 microRNAs exhibited significant differences in expression, also after adjustment for multiple measurements. For the 20 microRNAs with the greatest difference in expression the difference was up to more than 4 fold and with a P-value that were less than 4.4e^-8.

Conclusions

Significant differences were found in expression of more than 100 different microRNAs with up to 4 fold differences as a result of the intervention of selenium and coenzyme Q10 combined. The changes in microRNA could be a part of mechanisms underlying the clinical effects earlier reported that reduced cardiovascular mortality, gave better cardiac function, and showed less signs of inflammation and oxdative stress following the intervention. However, more research is needed to understand biological mechanisms of the protective effects of selenium and Q10 supplementation.

Screening of circulating microRNA biomarkers for prevalence of abdominal aortic aneurysm and aneurysm growth

BACKGROUND AND AIMS

MicroRNA (miR) are important regulators of gene expression and biological processes and have recently been suggested as possible biomarkers for abdominal aortic aneurysm (AAA) disease. The aim of the present study was to assess the role of miR as biomarkers for initiation and progression of AAA disease, through evaluation of a wide range of miRs in a large population-based cohort, with AAA patients with linked clinical data regarding risk factors, AAA size and growth, as well as controls.

METHODS

The expression of the 172 most commonly expressed miRs in plasma was analyzed by real-time PCR in samples from 169 screening-detected AAA patients and 48 age-matched controls.

RESULTS

For 103 miRs, there was a significant difference in expression between AAA and controls. Of these, 20 miRs were differently expressed between fast and slow growing aneurysms. These miRs target genes known to be involved in AAA disease as well as novel genes and pathways. By combining the top altered miRs together with clinical variables, strong predictive values, determining growth of AAA, were obtained (area under curve = 0.86, p < 0.001).

CONCLUSIONS

This large cohort study identified several novel miRs with altered expression in AAA patients when compared to controls. Assessment of miR expression may offer an opportunity to predict disease progression and aneurysm growth.

PDGF-D gene polymorphism is associated with increased cardiovascular mortality in elderly men

Background

Platelet-derived growth factor (PDGF) D has been reported to be active in fibroblasts, and in areas of myocardial infarction. In this longitudinal study we evaluated the association between PDGF-D polymorphism and cardiovascular mortality, and attempted to discover whether specific genotype differences regarding risk could be observed, and if gender differences could be seen.

Methods

Four hundred seventy-six elderly community participants were included in this study. All participants underwent a clinical examination, echocardiography, and blood sampling including PDGF-D single nucleotide polymorphism (SNP) analyses of the rs974819 A/A, G/A and G/G SNP. The follow-up time was 6.7 years.

Results

No specific genotype of rs974819 demonstrated increased cardiovascular mortality in the total population, however, the male group with genotypes A/A and G/A demonstrated an increased risk that persisted in a multivariate evaluation where adjustments were made for well-known cardiovascular risk factors (2.7 fold compared with the G/G genotype). No corresponding finding was observed in the female group.

Conclusion

We report here for the first time that the genotypes G/A or A/A of the SNP rs974819 near PDGF-D exhibited a 2.7 fold increased cardiovascular mortality risk in males. Corresponding increased risk could not be observed in either the total population and thus not in the female group. However, the sample size is was small and the results should be regarded as hypothesis-generating, and thus more research in the field is recommended.

Differences in cardiovascular toxicities associated with cigarette smoking and snuff use revealed using novel zebrafish models

Tobacco use is strongly associated with cardiovascular disease and the only avoidable risk factor associated with development of aortic aneurysm. While smoking is the most common form of tobacco use, snuff and other oral tobacco products are gaining popularity, but research on potentially toxic effects of oral tobacco use has not kept pace with the increase in its use. Here, we demonstrate that cigarette smoke and snuff extracts are highly toxic to developing zebrafish embryos. Exposure to such extracts led to a palette of toxic effects including early embryonic mortality, developmental delay, cerebral hemorrhages, defects in lymphatics development and ventricular function, and aneurysm development. Both cigarette smoke and snuff were more toxic than pure nicotine, indicating that other compounds in these products are also associated with toxicity. While some toxicities were found following exposure to both types of tobacco product, other toxicities, including developmental delay and aneurysm development, were specifically observed in the snuff extract group, whereas cerebral hemorrhages were only found in the group exposed to cigarette smoke extract. These findings deepen our understanding of the pathogenic effects of cigarette smoking and snuff use on the cardiovascular system and illustrate the benefits of using zebrafish to study mechanisms involved in aneurysm development.

Inflammatory cells, ceramides, and expression of proteases in perivascular adipose tissue adjacent to human abdominal aortic aneurysms

BACKGROUND

Abdominal aortic aneurysm (AAA) is a deadly irreversible weakening and distension of the abdominal aortic wall. The pathogenesis of AAA remains poorly understood. Investigation into the physical and molecular characteristics of perivascular adipose tissue (PVAT) adjacent to AAA has not been done before and is the purpose of this study.

METHODS AND RESULTS

Human aortae, periaortic PVAT, and fat surrounding peripheral arteries were collected from patients undergoing elective surgical repair of AAA. Control aortas were obtained from recently deceased healthy organ donors with no known arterial disease. Aorta and PVAT was found in AAA to larger extent compared with control aortas. Immunohistochemistry revealed neutrophils, macrophages, mast cells, and T-cells surrounding necrotic adipocytes. Gene expression analysis showed that neutrophils, mast cells, and T-cells were found to be increased in PVAT compared with AAA as well as cathepsin K and S. The concentration of ceramides in PVAT was determined using mass spectrometry and correlated with content of T-cells in the PVAT.

CONCLUSIONS

Our results suggest a role for abnormal necrotic, inflamed, proteolytic adipose tissue to the adjacent aneurysmal aortic wall in ongoing vascular damage.

Proteolytically active ADAM10 and ADAM17 carried on membrane microvesicles in human abdominal aortic aneurysms

The intraluminal thrombus (ILT) of human abdominal aortic aneurysm (AAA) has been suggested to damage the underlying aortic wall, but previous work found scant activity of soluble proteases in the abluminal layer of the ILT, adjacent to the aneurysm. We hypothesised that transmembrane proteases carried by membrane microvesicles (MV) from dying cells remain active in the abluminal ILT. ILTs and AAA segments collected from 21 patients during surgical repair were assayed for two major transmembrane proteases, ADAM10 (a disintegrin and metalloprotease-10) and ADAM17. We also exposed cultured cells to tobacco smoke and assessed ADAM10 and ADAM17 expression and release on MVs. Immunohistochemistry showed abundant ADAM10 and ADAM17 protein in the ILT and underlying aneurysmal aorta. Domain-specific antibodies indicated both transmembrane and shed ADAM17. Importantly, ADAM10 and ADAM 17 in the abluminal ILT were enzymatically active. Electron microscopy of abluminal ILT and aortic wall showed MVs with ADAM10 and ADAM17. By flow cytometry, ADAM-positive microvesicles from abluminal ILT carried the neutrophil marker CD66, but not the platelet marker CD61. Cultured HL60 neutrophils exposed to tobacco smoke extract showed increased ADAM10 and ADAM17 content, cleavage of these molecules into active forms, and release of MVs carrying mature ADAM10 and detectable ADAM17. In conclusion, our results implicate persistent, enzymatically active ADAMs on MVs in the abluminal ILT, adjacent to the aneurysmal wall. The production of ADAM10- and ADAM17-positive MVs from smoke-exposed neutrophils provides a novel molecular mechanism for the vastly accelerated risk of AAA in smokers.

Prognostic significance of PLA2G4C gene polymorphism in patients with stage II colorectal cancer

BACKGROUND

Phospholipase A2 Group IV C (PLA2G4C) catalyzes the release of certain fatty acids from phospholipids and plays a role in a range of physiological functions, such as remodeling of cell membranes and the production of prostaglandins. Furthermore, it has been proposed that PLA2G4C plays an important role in breast cancer cell chemotaxis. This study aimed to investigate the effect of a single nucleotide polymorphism (SNP) rs1549637 (T>A) of the PLA2G4C gene on the prognosis of colorectal cancer (CRC).

MATERIAL AND METHODS

Whole blood DNA was extracted from 381 patients with CRC and 618 controls, and a TaqMan SNP genotyping assay was used to determine the distribution of the genotypes. Cancer-specific and disease-free survival was analyzed by Kaplan-Meier graphs and by uni- and multivariable Cox regression.

RESULTS

The cancer-specific survival differed between the genotypes (p = 0.019) and the carriers of the A allele were associated with the highest risk of CRC death, with a hazard ratio (HR) of 1.72 [95% confidence interval (CI) 1.17-2.53, p = 0.006] compared with homozygous carriers of the T allele. This increased mortality in the carriers with the allele A was especially marked in stage II with an HR of 3.84 (95% CI 1.51-9.78, p = 0.005).

CONCLUSION

The A allele in PLA2G4C SNP (rs1549637) is associated with a worse prognosis in patients with CRC, especially in stage II disease, and it could be a potential prognostic biomarker in the planning of individual adjuvant therapy in stage II patients.

Gender difference in adiponectin associated with cardiovascular mortality

Background

It is important to identify cardiovascular diseases in patients at high risk. To include genetics into routine cardiological patients has therefore been discussed recently.

We wanted to evaluate the association between high-molecular weight adiponectin and cardiovascular risk, and secondly in the same population evaluate if specific genotype differences regarding risk could be observed, and thirdly if gender differences could be seen.

Method

Four hundred seventy-six elderly participants recruited from a rural community were included. All participants underwent a clinical examination, echocardiography, and blood sampling and the single nucleotide polymorphism (SNP) (rs266729) of adiponectin was analysed. Follow-up time was 6.7 years.

Results

Those with high serum concentration of adiponectin had a more 2 fold increased cardiovascular risk, and it might be that females exhibits even higher risk where a more than 5 fold increased risk could be seen. The result could be demonstrated even in a multivariate model adjusting for well-known clinical risk factors. However, as the sample size was small the gender differences should be interpreted with caution. In the genotype evaluation the C/C carriers of the female group had a more than 9-fold increased risk of cardiovascular mortality, however the confidence interval was wide. Such genotype difference could not be found in the male group.

Conclusion

High level of adiponectin was associated with increased cardiovascular risk. Also a gender difference in the genotype evaluation could be seen where the C/C carriers obtained higher risk in the female group but not in the male group. Thus, in order to identify patients at risk early, genetic analyses may add to the armamentarium used in the clinical routine. However, information should be regarded as hypothesis generating as the sample size was small and should stimulate further research in individualized cardiovascular prevention and treatment.

TRIF adaptor signaling is important in abdominal aortic aneurysm formation

OBJECTIVE

Abdominal aortic aneurysm (AAA) is characterized by inflammation, loss of smooth muscle cells (SMCs), and degradation of the extracellular matrix in the vessel wall. Innate immune receptors such as Toll-like receptors (TLRs) were recently shown to regulate immunological processes leading to the formation and progression of atherosclerotic plaques as well as to other cardiovascular pathologies. Our aim was to investigate whether blockage of TLR signaling, under the control of TIR domain-containing adaptor protein including IFN-β (TRIF), could inhibit the inflammatory response and AAA development in mice.

RESULTS

In human AAA, an increased TLR3 and TLR4 expression in association with macrophages and T lymphocytes was demonstrated with immunohistochemical analysis. Angiotensin (Ang) II-induced aneurysm formation was significantly reduced by 30% in ApoE(-/-)Trif(-/-) mice compared to ApoE(-/-) mice. Morphologically, AngII-infused ApoE(-/-)Trif(-/-) mice had a more intact cellular and extracellular matrix while ApoE(-/-) mice infused with AngII displayed an increased medial thickness associated with aortic dissection, thrombus formation, and a more disorganized vessel wall. Gene expression analysis of the abdominal aorta revealed a profound decrease of the inflammatory genes CD68 (P < 0.05), CD11b (P < 0.05), and TNF-α (P < 0.05) and the protease gene MMP-12 (P < 0.01) in ApoE(-/-)Trif(-/-) mice compared to ApoE(-/-) mice infused with AngII.

CONCLUSION

Our results suggest that signaling through TRIF is important for the inflammatory response of AngII-induced AAA and that blockage of the TRIF pathway reduces vascular inflammation and protects against AAA formation.

Imatinib reduces cholesterol uptake and matrix metalloproteinase activity in human THP-1 macrophages

BACKGROUND

Imatinib mesylate (Glivec®, formerly STI-571) is a selective tyrosine kinase inhibitor used for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. However, there are reports suggesting that imatinib could be atheroprotective by lowering plasma low-density lipoprotein (LDL).

AIM

To investigate the potential inhibitory effect of imatinib on cholesterol uptake in human macrophages as well as its effect on matrix metalloproteinase (MMP) activity.

METHODS AND RESULTS

Uptake of fluorescence-labeled LDL was analyzed using flow cytometry. Macrophages treated with imatinib showed a 23.5%, 27%, and 15% decrease in uptake of native LDL (p<0.05), acetylated LDL (p<0.01), and copper-modified oxidized LDL (p<0.01), respectively. Gel-based zymography showed that secretion and activity of MMP-2 and MMP-9 were inhibited by imatinib. Using GeneChip Whole Transcript Expression array analysis, no obvious gene candidates involved in the mechanisms of cholesterol metabolism or MMP regulation were found to be affected by imatinib. Instead, we found that imatinib up-regulated microRNA 155 (miR155) by 43.8% and down-regulated ADAM metallopeptidase domain 28 (ADAM28) by 41.4%. Both genes could potentially play an atheroprotective role and would be interesting targets in future studies.

CONCLUSION

Our results indicate that imatinib causes post-translational inhibition with respect to cholesterol uptake and regulation of MMP-2 and MMP-9. More research is needed to further evaluate the role of imatinib in the regulation of other genes and processes.

Increased Arterial Blood Pressure and Vascular Remodeling in Mice Lacking Salt-Inducible Kinase 1 (SIK1)

Rationale:

In human genetic studies a single nucleotide polymorphism within the salt-inducible kinase 1 ( SIK1 ) gene was associated with hypertension. Lower SIK1 activity in vascular smooth muscle cells (VSMCs) leads to decreased sodium-potassium ATPase activity, which associates with increased vascular tone. Also, SIK1 participates in a negative feedback mechanism on the transforming growth factor-β1 signaling and downregulation of SIK1 induces the expression of extracellular matrix remodeling genes.

Objective:

To evaluate whether reduced expression/activity of SIK1 alone or in combination with elevated salt intake could modify the structure and function of the vasculature, leading to higher blood pressure.

Methods and Results:

SIK1 knockout ( sik1 −/− ) and wild-type ( sik1 +/+ ) mice were challenged to a normal- or chronic high-salt intake (1% NaCl). Under normal-salt conditions, the sik1 −/− mice showed increased collagen deposition in the aorta but similar blood pressure compared with the sik1 +/+ mice. During high-salt intake, the sik1 +/+ mice exhibited an increase in SIK1 expression in the VSMCs layer of the aorta, whereas the sik1 −/− mice exhibited upregulated transforming growth factor-β1 signaling and increased expression of endothelin-1 and genes involved in VSMC contraction, higher systolic blood pressure, and signs of cardiac hypertrophy. In vitro knockdown of SIK1 induced upregulation of collagen in aortic adventitial fibroblasts and enhanced the expression of contractile markers and of endothelin-1 in VSMCs.

Conclusions:

Vascular SIK1 activation might represent a novel mechanism involved in the prevention of high blood pressure development triggered by high-salt intake through the modulation of the contractile phenotype of VSMCs via transforming growth factor-β1-signaling inhibition.

CD93 gene polymorphism is associated with disseminated colorectal cancer

PURPOSE

Cluster of differentiation 93 (CD93) is involved in apoptosis and inflammation and has a suggested role in angiogenesis, and all of which are involved in the development and dissemination of cancer. We evaluated the expression of CD93 and the association with two single nucleotide polymorphisms (SNPs), rs2749812 and rs2749817, as possible biomarkers in colorectal cancer (CRC).

METHODS

Tissue levels and plasma levels of CD93 were measured using an enzyme-linked immunosorbent assay (ELISA). Expression of CD93 was determined by immunohistochemistry, western blot and gene expression analysis. Genotype frequencies were established for the SNPs by real-time polymerase chain reaction (PCR), and the association with tumour stage and survival was analysed.

RESULTS

Total CD93 levels were 82% higher (P < 0.001) in tumours compared to matched normal tissues. Mean levels of soluble CD93 in plasma were 30% lower (P < 0.001) in the patients compared to the controls. The T/T genotype of SNP rs2749817 was more common in stage IV patients, with consequently higher risk of CRC death (T/T vs. C/C and C/T; hazard ratio (HR) = 1.73, 95% confidence interval (CI) = 1.11-2.67, P = 0.014), and was associated with a higher risk of CRC recurrence after radical operation (T/T vs. C/C and C/T; HR = 2.07, CI = 1.22-3.51, P = 0.007).

CONCLUSIONS

We showed that the T/T genotype of SNP rs2749817 is associated with disseminated cancer at diagnosis and an increased recurrence rate after radical operation. Patients with this genotype may benefit from early identification.

Impaired collagen biosynthesis and cross-linking in aorta of patients with bicuspid aortic valve

Background

Patients with bicuspid aortic valve (BAV) have an increased risk of developing ascending aortic aneurysm. In the present study, collagen homeostasis in nondilated and dilated aorta segments from patients with BAV was studied, with normal and dilated aortas from tricuspid aortic valve (TAV) patients as reference.

Methods and Results

Ascending aortas from 56 patients were used for biochemical and morphological analyses of collagen. mRNA expression was analyzed in 109 patients. Collagen turnover rates were similar in nondilated and dilated aortas of BAV patients, showing that aneurysmal formation in BAV is, in contrast to TAV, not associated with an increased collagen turnover. However, BAV in general was associated with an increased aortic collagen turnover compared with nondilated aortas of TAV patients. Importantly, the ratio of hydroxylysyl pyridinoline (HP) to lysyl pyridinoline (LP), 2 distinct forms of collagen cross‐linking, was lower in dilated aortas from patients with BAV, which suggests that BAV is associated with a defect in the posttranslational collagen modification. This suggests a deficiency at the level of lysyl hydroxylase (PLOD1), which was confirmed by mRNA and protein analyses that showed reduced PLOD1 expression but normal lysyl oxidase expression in dilated aortas from patients with BAV. This suggests that impaired collagen cross‐linking in BAV patients may be attributed to changes in the expression and/or activity of PLOD1.

Conclusions

Our results demonstrate an impaired biosynthesis and posttranslational modification of collagen in aortas of patients with BAV, which may explain the increased aortic aneurysm formation in BAV patients.

Tumour-derived adhesion factor in colorectal cancer

Tumour-derived adhesion factor (TAF) has been shown to be associated with breast, prostate and colorectal cancer (CRC), acting as tumour suppressor or tumour promoter by mechanisms not as yet understood. Here, we comparatively analyzed the expression profile of TAF in plasma, tumour and paired normal tissue from patients with CRC. In addition, we investigated the relationship between TAF and systemic inflammation, mirrored by the elevation of interleukin-6 (IL-6) and TAF levels in plasma. Levels of TAF and IL-6 were determined by ELISA. Immunohistochemistry was performed to investigate the site of TAF expression. We also used a TaqMan system to investigate a TAF single nucleotide polymorphism (rs2041437) with a potential effect on CRC. TAF protein levels were significantly (P<0.001) higher in colorectal tumours than in normal tissue, and were increased in patients with Dukes' stages B and C compared to A. Immunohistochemistry revealed heterogeneous TAF expression mainly in the epithelial cells of the cancer and normal tissue. The plasma TAF level was reduced in CRC patients compared with the controls (P=0.002), independent of the inflammatory marker IL-6. Regarding genotype and allelic distributions, significant differences between CRC patients and control subjects or associations between clinical characteristics and TAF levels in tissue and plasma were not observed. In conclusion, altered TAF protein expression in cancer tissue may be a potential biomarker in colorectal carcinogenesis. Further research exploring the regulation of TAF is required to evaluate whether TAF is linked to clinical outcome.

Serine protease inhibitor A3 in atherosclerosis and aneurysm disease

Remodeling of extracellular matrix (ECM) plays an important role in both atherosclerosis and aneurysm disease. Serine protease inhibitor A3 (serpinA3) is an inhibitor of several proteases such as elastase, cathepsin G and chymase derived from mast cells and neutrophils. In this study, we investigated the putative role of serpinA3 in atherosclerosis and aneurysm formation. SerpinA3 was expressed in endothelial cells and medial smooth muscle cells in human atherosclerotic lesions and a 14-fold increased expression of serpinA3n mRNA was found in lesions from Apoe-/- mice compared to lesion-free vessels. In contrast, decreased mRNA expression (-80%) of serpinA3 was found in biopsies of human abdominal aortic aneurysm (AAA) compared to non-dilated aortas. Overexpression of serpinA3n in transgenic mice did not influence the development of atherosclerosis or CaCl2-induced aneurysm formation. In situ zymography analysis showed that the transgenic mice had lower cathepsin G and elastase activity, and more elastin in the aortas compared to wild-type mice, which could indicate a more stable aortic phenotype. Differential vascular expression of serpinA3 is clearly associated with human atherosclerosis and AAA but serpinA3 had no major effect on experimentally induced atherosclerosis or AAA development in mouse. However, serpinA3 may be involved in a phenotypic stabilization of the aorta.

Unraveling divergent gene expression profiles in bicuspid and tricuspid aortic valve patients with thoracic aortic dilatation: the ASAP study

Thoracic aortic aneurysm (TAA) is a common complication in patients with a bicuspid aortic valve (BAV), the most frequent congenital heart disorder. For unknown reasons TAA occurs at a younger age, with a higher frequency in BAV patients than in patients with a tricuspid aortic valve (TAV), resulting in an increased risk for aortic dissection and rupture. To investigate the increased TAA incidence in BAV patients, we obtained tissue biopsy samples from nondilated and dilated aortas of 131 BAV and TAV patients. Global gene expression profiles were analyzed from controls and from aortic intima-media and adventitia of patients (in total 345 samples). Of the genes found to be differentially expressed with dilation, only a few (<4%) were differentially expressed in both BAV and TAV patients. With the use of gene set enrichment analysis, the cell adhesion and extracellular region gene ontology sets were identified as common features of TAA in both BAV and TAV patients. Immune response genes were observed to be particularly overexpressed in the aortic media of dilated TAV samples. The divergent gene expression profiles indicate that there are fundamental differences in TAA etiology in BAV and TAV patients. Immune response activation solely in the aortic media of TAV patients suggests that inflammation is involved in TAA formation in TAV but not in BAV patients. Conversely, genes were identified that were only differentially expressed with dilation in BAV patients. The result has bearing on future clinical studies in which separate analysis of BAV and TAV patients is recommended.

Plasma CD93 concentration is a potential novel biomarker for coronary artery disease

OBJECTIVES

A common nonsynonymous single nucleotide polymorphism (SNP) in the CD93 gene (rs3746731, Pro541Ser) has been associated with risk of coronary artery disease (CAD). CD93 is a transmembrane glycoprotein, which is detectable in soluble form in human plasma. We investigated whether the concentration of soluble CD93 in plasma is related to risk of myocardial infarction (MI) and CAD, using a case-control study of premature MI (n = 764) and a nested case-control analysis of a longitudinal cohort study of 60-year-old subjects (analysis comprising 844 of 4232 subjects enrolled at baseline). In addition, SNPs in the CD93 gene were studied in relation to plasma CD93 concentration and CD93 mRNA expression.

METHODS AND RESULTS

A sensitive and specific enzyme-linked immunosorbent assay was established for determination of the plasma CD93 concentration. Subjects were divided into three groups according to tertiles of the distribution of CD93 concentration. Lower odds ratios for risk of MI and incidence of CAD were observed in the middle CD93 tertile (142-173 μg L(-1) ): odds ratio (95% confidence interval), 0.69 (0.49-0.97) and 0.61 (0.40-0.94), respectively. These associations were independent of traditional CAD risk factors. The minor allele of a SNP in the 3' untranslated region of CD93 (rs2749812) was associated with increased plasma CD93 concentrations (P = 0.03) and increased CD93 mRNA expression levels (P = 0.02).

CONCLUSION

The results of the present study suggest that the concentration of soluble CD93 in plasma is a potential novel biomarker for CAD, including MI.

Comparison of dorsocervical with abdominal subcutaneous adipose tissue in patients with and without antiretroviral therapy-associated lipodystrophy

OBJECTIVE

Combination antiretroviral therapy (cART) is associated with lipodystrophy, i.e., loss of subcutaneous adipose tissue in the abdomen, limbs, and face and its accumulation intra-abdominally. No fat is lost dorsocervically and it can even accumulate in this region (buffalo hump). It is unknown how preserved dorsocervical fat differs from abdominal subcutaneous fat in HIV-1-infected cART-treated patients with (cART+LD+) and without (cART+LD-) lipodystrophy.

RESEARCH DESIGN AND METHODS

We used histology, microarray, PCR, and magnetic resonance imaging to compare dorsocervical and abdominal subcutaneous adipose tissue in cART+LD+ (n=21) and cART+LD- (n=11).

RESULTS

Albeit dorsocervical adipose tissue in cART+LD+ seems spared from lipoatrophy, its mitochondrial DNA (mtDNA; copies/cell) content was significantly lower (by 62%) than that of the corresponding tissue in cART+LD-. Expression of CD68 mRNA, a marker of macrophages, and numerous inflammatory genes in microarray were significantly lower in dorsocervical versus abdominal subcutaneous adipose tissue. Genes with the greatest difference in expression between the two depots were those involved in regulation of transcription and regionalization (homeobox genes), irrespective of lipodystrophy status. There was negligible mRNA expression of uncoupling protein 1, a gene characteristic of brown adipose tissue, in either depot.

CONCLUSIONS

Because mtDNA is depleted even in the nonatrophic dorsocervical adipose tissue, it is unlikely that the cause of lipoatrophy is loss of mtDNA. Dorsocervical adipose tissue is less inflamed than lipoatrophic adipose tissue. It does not resemble brown adipose tissue. The greatest difference in gene expression between dorsocervical and abdominal subcutaneous adipose tissue is in expression of homeobox genes.