Associations of IGF1 and its binding proteins with abdominal aortic aneurysm and aortic diameter in older men

Insulin-like Growth Factor-Binding Protein-1 (IGFBP-1) as a Biomarker of Cardiovascular Disease

Insulin-like growth factor-binding protein-1 (IGFBP-1) contributes to the regulation of IGFs for metabolism and growth and has IGF-independent actions. IGFBP-1 in the circulation is derived from the liver, where it is inhibited by insulin and stimulated by multiple factors, including proinflammatory cytokines. IGFBP-1 levels are influenced by sex and age, which also determine cardiometabolic risk and patterns of disease presentation. While lower circulating IGFBP-1 concentrations are associated with an unfavorable cardiometabolic risk profile, higher IGFBP-1 predicts worse cardiovascular disease outcomes. This review explores these associations and the possible roles of IGFBP-1 in the pathophysiology of atherosclerosis. We recommend the evaluation of dynamic approaches, such as simultaneous measurements of fasting IGFBP-1 and proinsulin level in response to an oral glucose challenge, as well as multi-marker approaches incorporating markers of inflammation.

Extravascular administration of IGF1R antagonists protects against aortic aneurysm in rodent and porcine models

An abdominal aortic aneurysm (AAA) is a life-threatening cardiovascular disease. We identified plasma insulin-like growth factor 1 (IGF1) as an independent risk factor in patients with AAA by correlating plasma IGF1 with risk. Smooth muscle cell- or fibroblast-specific knockout of Igf1r, the gene encoding the IGF1 receptor (IGF1R), attenuated AAA formation in two mouse models of AAA induced by angiotensin II infusion or CaCl2 treatment. IGF1R was activated in aortic aneurysm samples from human patients and mice with AAA. Systemic administration of IGF1C, a peptide fragment of IGF1, 2 weeks after disease development inhibited AAA progression in mice. Decreased AAA formation was linked to competitive inhibition of IGF1 binding to its receptor by IGF1C and modulation of downstream alpha serine/threonine protein kinase (AKT)/mammalian target of rapamycin signaling. Localized application of an IGF1C-loaded hydrogel was developed to reduce the side effects observed after systemic administration of IGF1C or IGF1R antagonists in the CaCl2-induced AAA mouse model. The inhibitory effect of the IGF1C-loaded hydrogel administered at disease onset on AAA formation was further evaluated in a guinea pig-to-rat xenograft model and in a sheep-to-minipig xenograft model of AAA formation. The therapeutic efficacy of IGF1C for treating AAA was tested through extravascular delivery in the sheep-to-minipig model with AAA established for 2 weeks. Percutaneous injection of the IGF1C-loaded hydrogel around the AAA resulted in improved vessel flow dynamics in the minipig aorta. These findings suggest that extravascular administration of IGF1R antagonists may have translational potential for treating AAA.

Label-free electrochemical immunosensor for detection of insulin-like growth factor-1 (IGF-1) using a specific monoclonal receptor on electrospun Zein-based nanofibers/rGO-modified electrode

A novel electrochemical immunosensor was developed for ultrasensitive determination of the hormone insulin-like growth factor 1 (IGF-1) based on immobilization of a specific monoclonal antibody on the electrospun nanofibers of Polyacrylonitrile (PAN)/Zein-reduced graphene oxide (rGO) nanoparticle. The nanofibers deposited on glassy carbon electrode (GCE) showed good electrochemical behaviors with synergistic effects between PAN, Zein, and rGO. PAN/Zein nanofibers were used due to flexibility, high porosity, good mechanical strength, high specific surface area, and flexible structures, while rGO nanoparticles were used to improve the detection sensitivity and anti-IGF-1 immobilizing. Different characterization techniques were applied consisting of FE-SEM, FT-IR, and EDS for the investigation of morphological features and nanofiber size. The redox reactions of [Fe(CN)6]4-/3- on the modified electrode surface were probed for studying the immobilization and determination processes, using differential pulse voltammetry (DPV) and cyclic voltammetry (CV). Under optimal conditions, LOD (limit of detection) and LOQ (limit of quantification) were obtained as 55.72 fg/mL and 185.73 fg/mL respectively, and sensitivity was acquired 136.29 μA/cm2.dec. Moreover, a wide linear range was obtained ranging from 1 pg/mL to 10 ng/mL for IGF-1. Furthermore, the proposed method was applied for the analysis of IGF-1 in several human plasma samples with acceptable results, and it also exhibited high selectivity, stability, and reproducibility.

Systematical Evaluation of the Structure-Cardiotoxicity Relationship of 7-Azaindazole-based PI3K Inhibitors Designed by Bioisosteric Approach

A growing concern of cardiotoxicity induced by PI3K inhibitors has raised the requirements to evaluate the structure-cardiotoxicity relationship (SCR) in the development process of novel inhibitors. Based on three bioisosteric 7-azaindazole-based candidate inhibitors namely FD269, FD268 and FD274 that give same order of inhibitory concentration 50% (IC50) magnitude against PI3Ks, in this work, we proposed to systematically evaluate the SCR of 7-azaindazole-based PI3K inhibitors designed by bioisosteric approach. The 24-h lethal concentrations 50% (LC50) of FD269, FD268 and FD274 against zebrafish embryos were 0.35, 4.82 and above 50 μM (not detected), respectively. Determination of the heart rate, pericardial and yolk-sac areas and vascular malformation confirmed the remarkable reduction in the cardiotoxicity of from FD269 to FD268 and to FD274. The IC50s of all three compounds against the hERG channel were tested on the CHO cell line that constitutively expressing hERG channel, which were all higher than 20 μM. The transcriptomic analysis revealed that FD269 and FD268 induced the up-regulation of noxo1b, which encodes a subunit of an NADPH oxidase evoking the oxidative stress. Furthermore, immunohistochemistry tests confirmed the structure-dependent attenuation of the overproduction of ROS and cardiac apoptosis. Our results verified the feasibility of bioisosteric replacement to attenuate the cardiotoxicity of 7-azaindazole-based PI3K inhibitors, suggesting that the screening for PI3K inhibitors with both high potency and low cardiotoxicity from bioisosteres would be a beneficial trial.

Progression of Thoracic Aortic Dissection Is Aggravated by the hsa_circ_0007386/miR-1271-5P/IGF1R/AKT Axis via Induction of Arterial Smooth Muscle Cell Apoptosis

BACKGROUND

The molecular mechanisms associated with thoracic aortic dissection (TAD) remain poorly understood. A comprehensive high-throughput sequencing-based analysis of the circRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) regulatory network in TAD has not been conducted. The purpose of this study is to identify and verify the key ceRNA networks which may have crucial biological functions in the pathogenesis of TAD.

METHODS

Gene expression profiles of the GSE97745, GSE98770, and GSE52093 datasets were acquired from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the GEO2R tools. Protein-protein interaction (PPI) networks of the hub genes were constructed using STRING; the hub genes and modules were identified by MCODE and CytoHubba plugins of the Cytoscape. We analyzed the hub genes using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. The functions of these hub genes were assessed using Cytoscape software. Our data-along with data from GSE97745, GSE98770, and GSE52093-were used to verify the findings.

RESULTS

Upon combined biological prediction, a total of 11 ce-circRNAs, 11 ce-miRNAs, and 26 ce-mRNAs were screened to construct a circRNA-miRNA-mRNA ceRNA network. PPI network and module analysis identified four hub nodes, including IGF1R, JAK2, CSF1, and GAB1. Genes associated with the Ras and PI3K-Akt signaling pathways were clustered in the four hub node modules in TAD. The node degrees were most significant for IGF1R, which were also the most significant in the two modules (up module and hub module). IGF1R was selected as a key gene, and the hsa_circ_0007386/miR-1271-5P/IGF1R/AKT regulatory axis was established. The relative expression levels of the regulatory axis members were confirmed by RT-PCR in 12 samples, including TAD tissues and normal tissues. Downregulation of IGF1R expression in smooth muscle cells (SMCs) was found to induce apoptosis by regulating the AKT levels. In addition, IGF1R showed high diagnostic efficacy in both AD tissue and blood samples.

CONCLUSIONS

The hsa_circ_0007386/miR-1271-5P/IGF1R/AKT axis may aggravate the progression of TAD by inducing VSMCs apoptosis. CeRNA networks could provide new insights into the underlying molecular mechanisms of TAD. In addition, IGF1R showed high diagnostic efficacy in both tissue and plasma samples in TAD, which can be considered as a diagnostic marker for TAD.

Ageing- and AAA-associated differentially expressed proteins identified by proteomic analysis in mice

Background

Abdominal aortic aneurysm (AAA) is a disease of high prevalence in old age, and its incidence gradually increases with increasing age. There were few studies about differences in the circulatory system in the incidence of AAA, mainly because younger patients with AAA are fewer and more comorbid nonatherosclerotic factors.

Method

We induced AAA in ApoE^-/- male mice of different ages (10 or 24 weeks) and obtained plasma samples. After the top 14 most abundant proteins were detected, the plasma was analyzed by a proteomic study using the data-dependent acquisition (DDA) technique. The proteomic results were compared between different groups to identify age-related differentially expressed proteins (DEPs) in the circulation that contribute to AAA formation. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction (PPI) network analyses were performed by R software. The top 10 proteins were determined with the MCC method of Cytoscape, and transcription factor (TF) prediction of the DEPs was performed with iRegulon (Cytoscape).

Results

The aortic diameter fold increase was higher in the aged group than in the youth group (p < 0.01). Overall, 92 DEPs related to age and involved in AAA formation were identified. GO analysis of the DEPs showed enrichment of the terms wounding healing, response to oxidative stress, regulation of body fluid levels, ribose phosphate metabolic process, and blood coagulation. The KEGG pathway analysis showed enrichment of the terms platelet activation, complement and coagulation cascades, glycolysis/gluconeogenesis, carbon metabolism, biosynthesis of amino acids, and ECM-receptor interaction. The top 10 proteins were Tpi1, Eno1, Prdx1, Ppia, Prdx6, Vwf, Prdx2, Fga, Fgg, and Fgb, and the predicted TFs of these proteins were Nfe2, Srf, Epas1, Tbp, and Hoxc8.

Conclusion

The identified proteins related to age and involved in AAA formation were associated with the response to oxidative stress, coagulation and platelet activation, and complement and inflammation pathways, and the TFs of these proteins might be potential targets for AAA treatments. Further experimental and biological studies are needed to elucidate the role of these age-associated and AAA-related proteins in the progression of AAA.

Biomolecular assembly on interdigitated electrode nanosensor for selective detection of insulin-like growth factor-1

This research is focussed to quantify IGF1 by electroanalytical analysis on InterDigitated electrode surface and characterized by the microscopic observations. For the detection, antibody and aptamer were used to analyze the level of IGF1. The sandwich pattern (aptamer-IGF1-antibody) was designed on the chemically modified IDE surface and reached the limit of detection to 10 fM with 100 folds enhancement in the sensitivity. Different control experiments (absence of IGF1, binding with IGF2 and with non-complementary aptamer) were failed to show the current changes, discriminated the specific detection. A good detection strategy is to complement the currently following imaging systems for AAA.

Novel Blood Biomarkers for a Diagnostic Workup of Acute Aortic Dissection

Acute aortic dissection (AAD) is a rare condition, but together with acute myocardial infarction (AMI) and pulmonary embolism (PE) it belongs to the most relevant and life-threatening causes of acute chest pain. Until now, there has been no specific blood test in the diagnostic workup of AAD. To identify clinically relevant biomarkers for AAD, we applied Proseek^® Multiplex assays to plasma samples from patients with AAD, AMI, PE, thoracic aortic aneurysm (TAA), and non-cardiovascular chest pain (nonCVD). Subsequently, we validated top hits using conventional immunoassays and examined their expression in the aortic tissue. Interleukin 10 (IL-10) alone showed the best performance with a sensitivity of 55% and a specificity of 98% for AAD diagnosis. The combination of D-dimers, high-sensitive troponin T (hs-TnT), interleukin 6 (IL-6), and plasminogen activator inhibitor 1 (PAI1) correctly classified 75% of AAD cases, delivering a sensitivity of 83% and specificity of 95% for its diagnosis. Moreover, this model provided the correct classification of 77% of all analyzed cases. Our data suggest that IL-10 shows potential to be a rule-in biomarker for AAD. Moreover, the addition of PAI1 and IL-6 to hs-TnT and D-dimers may improve the discrimination of suspected AAD, AMI, and PE in patients presenting with acute chest pain.

Serum IGFBP-1 as a potential biomarker for diagnosis of early-stage upper gastrointestinal tumour

BACKGROUND

Early detection would improve upper gastrointestinal cancer prognosis. We aimed to identify serum protein biomarker for the detection of early-stage upper gastrointestinal cancer.

METHODS

We performed a three-tiered study including 2028 participants from three medical centres. First, we applied two different antibody arrays to screen candidate serum proteins that increased in 20 patients with oesophageal squamous cell carcinoma (ESCC) compared with 20 normal controls. We then evaluated the selected protein by enzyme-linked immunosorbent assay in 1064 participants including 731 upper gastrointestinal cancer patients (287 ESCCs, 237 oesophagogastric junction adenocarcinomas (EJAs), and 207 stomach cancers) and 333 normal controls. The diagnostic value of the selected protein was finally validated in two independent cohorts of ESCC patients and controls (n=472 and 452, respectively). The receiver operating characteristic was used to calculate diagnostic accuracy.

FINDINGS

Serum insulin-like growth factor binding protein-1 (IGFBP-1) identified in both antibody arrays showed significantly elevated levels in upper gastrointestinal cancers, compared with normal controls. Serum IGFBP-1 provided high diagnostic accuracy of early-stage ESCC, EJA, stomach and cancer (areas under the curve: 0·898, 0·936 and 0·864, respectively). This protein maintained diagnostic performance for early-stage ESCC in independent cohorts 1 and 2 (0·849 and 0·911, respectively). Additionally, serum levels of IGFBP-1 dropped significantly after surgical resection of primary tumours, compared with the corresponding pre-operative ESCC samples (p < 0·05).

INTERPRETATION

Serum IGFBP-1 represents a promising diagnostic biomarker to detect early-stage upper gastrointestinal cancer.

Positive association between abdominal aortic diameter and serum collagen XVIII levels

BACKGROUND

The identification of abdominal aortic aneurysm (AAA) biomarker offers a perspective to determine disease progress and rupture risk. The aim of our study was to evaluate the association between selected circulating biomarkers and diameter of abdominal aorta.

METHODS

One hundred and two patients (88 men and 14 women) with mean age 70.0±8.7 years were included in a single center cross-sectional study conducted between February 2016 and October, 2018. AAA was defined as subrenal aortic dilatation ≥3 cm. Serum biomarker concentrations (insulin-like growth factor-1, peroxiredoxin-1, collagen IV, collagen XVIII) were measured by an enzyme-linked immunosorbent assay (ELISA). Adjustments including variables with different baseline distribution at univariate level with P<0.1 (age, body mass index, coronary artery disease, fibrinogen) were performed in multivariate models.

RESULTS

Higher collagen XVIII was found in AAA patients in comparison with the control group of patients (39.5 vs. 25.0 ng/mL; P=0.002). Diameter of abdominal aorta was positively associated with collagen XVIII levels in univariate (B=0.16; P=0.004), and in multivariate analysis (B=0.14; P=0.027), i.e. increase in collagen XVIII by 1 ng/mL corresponded to an increase in abdominal aortic diameter by 0.14 mm. Patients with serum collagen XVIII levels in the third tertile (˃47 ng/mL) had 4.23 times higher risk of AAA compared to patients with collagen XVIII levels in the first and second tertiles (OR 4.23; 95% CI 1.42-11.6; P=0.020). No association was found between other examined biomarkers and abdominal aortic diameter.

CONCLUSIONS

Diameter of abdominal aorta was positively associated with serum collagen XVIII level.

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.

Identification of the miRNA-target gene regulatory network in intracranial aneurysm based on microarray expression data

Intracranial aneurysm (IA) remains one of the most devastating neurological conditions. However, the pathophysiology of IA formation and rupture still remains unclear. The purpose of the present study was to identify the crucial microRNA (miRNA/miR) and genes involved in IAs and elucidate the mechanisms underlying the development of IAs. In the present study, novel miRNA regulation activities in IAs were investigated through the integration of public gene expression data of miRNA and mRNA using the Gene Expression Omnibus database, combined with bioinformatics prediction. A total of 15 differentially expressed miRNA and 1,447 differentially expressed mRNA between IAs and controls were identified. A number of miRNA-target gene pairs (770), whose expression levels were inversely correlated, were used to construct a regulatory network of miRNA-target genes in IAs. The biological functions and pathways of these target genes were revealed to be associated with IAs. Specific miRNA and genes, such as hsa-let-7f, hsa-let-7d, hsa-miR-7, RPS6KA3, TSC1 and IGF1 may possess key roles in the development of IAs. The integrated analysis in the present study may provide insights into the understanding of underlying molecular mechanisms of IAs and novel therapeutic targets.

Diabetes and Abdominal Aortic Aneurysm Growth

We performed a systematic literature search and a meta-analysis to assess the association between diabetes mellitus (DM) and abdominal aortic aneurysm (AAA) growth. Databases including MEDLINE and EMBASE were searched through June 2015 using PubMed and OVID. For each study, data regarding AAA growth rates in both the DM and the non-DM groups were used to generate standardized mean differences (SMDs) and 95% confidence intervals (CIs). Our search identified 19 relevant studies including data on 9777 patients with AAA. Pooled analyses demonstrated a statistically significant slower growth rates in DM patients than in non-DM patients (unadjusted SMD, −0.32; 95% CI, −0.40 to −0.24; P < .00001; adjusted SMD, −0.29; 95% CI, −0.417 to −0.18; P < .00001). Despite possible publication bias in favor of DM based on funnel plot asymmetry, even adjustment of the asymmetry did not alter the beneficial effect of DM. In conclusion, on the basis of a meta-analysis of data on a total of 9777 patients (19 studies) identified through a systematic literature search, we confirmed the association of DM with slower growth rates of AAA.

Impact of insulin like growth factor-1 in development of coronary artery ectasia

Coronary artery ectasia (CAE) is characterized by inappropriate dilatation of the coronary vasculature. The mechanisms of CAE are not well known. Insulin-like growth factor-1 (IGF-1) may make endothelial cells and smooth muscle cells more sensitive to the effects of growth hormone. In the present study, we hypothesized that IGF-1 may have an impact on the formation of ectasia and aneurysm in arterial system, and aimed to investigate the associations between the presence of CAE and serum IGF-1 levels in patients undergoing coronary angiography. The study included 2.980 subjects undergoing elective diagnostic coronary angiography. We selected 40 patients diagnosed with CAE as CAE group and 44 subjects with absolutely normal coronary arteries were assigned as normal control group. IGF-1 levels were measured in both groups of patients. Groups were similar in terms of age, sex and coronary artery disease risk factors. The serum IGF-1 levels were significantly higher in CAE patients with 109.64 ± 54.64 ng/mL than in controls with 84.76 ± 34.01 ng/mL (p=0.016). HDL levels were lower in ectasia group with 41.5 ± 10.7 mg/dL than controls with 47.7 ± 10.4 mg/dL (p=0.018). By means of logistic regression analysis, high IGF-1 and low HDL levels were found to be independent risk factors for the presence of CAE (p<0.02, p<0.016, respectively). The study revealed that there was a positive correlation between serum IGF-1 levels and presence of CAE, and high IGF-1 levels and low HDL levels were independent risk factors for the presence of CAE. Future studies are needed to confirm these results.

Meta-analysis and meta-regression analysis of biomarkers for abdominal aortic aneurysm

Background

Many studies have investigated the systemic and local expression of biomarkers in patients with abdominal aortic aneurysm (AAA). The natural history of AAA varies between patients, and predictors of the presence and diameter of AAA have not been determined consistently. The aim of this study was to perform a systematic review, meta-analysis and meta-regression of studies comparing biomarkers in patients with and without AAA, with the aim of summarizing the association of identified markers with both AAA presence and size.

Methods and results

Literature review identified 106 studies suitable for inclusion. Meta-analysis demonstrated a significant difference between matrix metalloproteinase (MMP) 9, tissue inhibitor of matrix metalloproteinase 1, interleukin (IL) 6, C-reactive protein (CRP), α1-antitrypsin, triglycerides, lipoprotein(a), apolipoprotein A and high-density lipoprotein in patients with and without AAA. Although meta-analysis was not possible for MMP-2 in aortic tissue, tumour necrosis factor α, osteoprotegerin, osteopontin, interferon γ, intercellular cell adhesion molecule 1 and vascular cell adhesion molecule 1, systematic review suggested an increase in these biomarkers in patients with AAA. Meta-regression analysis identified a significant positive linear correlation between aortic diameter and CRP level.

Conclusion

A wide variety of biomarkers are dysregulated in patients with AAA, but their clinical value is yet to be established. Future research should focus on the most relevant biomarkers of AAA, and how they could be used clinically.

Endothelin-1-induced focal cerebral ischemia in the growth hormone/IGF-1 deficient Lewis Dwarf rat

Aging is a major risk factor for cerebrovascular disease. Growth hormone (GH) and its anabolic mediator, insulin-like growth factor (IGF)-1, decrease with advancing age and this decline has been shown to promote vascular dysfunction. In addition, lower GH/IGF-1 levels are associated with higher stroke mortality in humans. These results suggest that decreased GH/IGF-1 level is an important factor in increased risk of cerebrovascular diseases. This study was designed to assess whether GH/IGF-1-deficiency influences the outcome of cerebral ischemia. We found that endothelin-1-induced middle cerebral artery occlusion resulted in a modest but nonsignificant decrease in cerebral infarct size in GH/IGF-1 deficient dw/dw rats compared with control heterozygous littermates and dw/dw rats with early-life GH treatment. Expression of endothelin receptors and endothelin-1-induced constriction of the middle cerebral arteries were similar in the three experimental groups. Interestingly, dw/dw rats exhibited reduced brain edema and less astrocytic infiltration compared with their heterozygous littermates and this effect was reversed by GH-treatment. Because reactive astrocytes are critical for the regulation of poststroke inflammatory processes, maintenance of the blood-brain barrier and neural repair, further studies are warranted to determine the long-term functional consequences of decreased astrocytic activation in GH/IGF-1 deficient animals after cerebral ischemia.