Role of vascular endothelial growth factor-A in development of abdominal aortic aneurysm

Ketosis prevents abdominal aortic aneurysm rupture through C-C chemokine receptor type 2 downregulation and enhanced extracellular matrix balance

Abdominal aortic aneurysms (AAAs) are prevalent with aging, and AAA rupture is associated with increased mortality. There is currently no effective medical therapy to prevent AAA rupture. The monocyte chemoattractant protein (MCP-1)/C-C chemokine receptor type 2 (CCR2) axis critically regulates AAA inflammation, matrix-metalloproteinase (MMP) production, and extracellular matrix (ECM) stability. We therefore hypothesized that a diet intervention that can modulate CCR2 axis may therapeutically impact AAA risk of rupture. Since ketone bodies (KBs) can trigger repair mechanisms in response to inflammation, we evaluated whether systemic ketosis in vivo could reduce CCR2 and AAA progression. Male Sprague-Dawley rats underwent surgical AAA formation using porcine pancreatic elastase and received daily β-aminopropionitrile to promote AAA rupture. Rats with AAAs received either a standard diet, ketogenic diet (KD), or exogenous KBs (EKB). Rats receiving KD and EKB reached a state of ketosis and had significant reduction in AAA expansion and incidence of rupture. Ketosis also led to significantly reduced aortic CCR2 content, improved MMP balance, and reduced ECM degradation. Consistent with these findings, we also observed that Ccr2-/- mice have significantly reduced AAA expansion and rupture. In summary, this study demonstrates that CCR2 is essential for AAA expansion, and that its modulation with ketosis can reduce AAA pathology. This provides an impetus for future clinical studies that will evaluate the impact of ketosis on human AAA disease.

The protective effects of pirfenidone in preventing abdominal aortic aneurysm formation

Vascular endothelial growth factor (VEGF)-mediated angiogenesis participates in the initiation and progression of abdominal aortic aneurysm (AAA). Pirfenidone is a compound that has anti-inflammatory and antioxidant properties and suppresses angiogenesis. Pirfenidone targets the extracellular matrix (ECM) and has therapeutic effects on fibrotic diseases. Therefore, we speculated that pirfenidone might have meaningful therapeutic effects in AAA, and the current study was designed to investigate this capacity. An AAA model was constructed in mice using a long-term injection of angiotensin II (Ang II), followed by a 28-day administration of 200 mg/kg/day pirfenidone. Increased maximal external diameter of the abdominal artery, promoted levels of VEGF-A and its receptor VEGF-R2, upregulated matrix metallopeptidases (MMP)-2 and MMP-9, and elevated release of pro-inflammatory cytokines were observed in AAA mice, which were extremely repressed by 200 mg/kg pirfenidone. Human aortic endothelial cells (HAECs) were stimulated with Ang II for 1 day, in the presence or absence of pirfenidone (100 nM). Elevated expression of VEGF-A and VEGF-R2, facilitated proliferation, increased tube formation ability, and upregulated MMP-2 and MMP-9 were observed in Ang II-stimulated HAECs, all of which were significantly rescued by 100 nM pirfenidone. Finally, the elevated levels of myeloid differentiation primary response 88 and phosphorylated nuclear factor-kappa-B subunit p65 observed in Ang II-stimulated HAECs were repressed by pirfenidone. Collectively, pirfenidone alleviated AAA by inhibiting ECM degradation and ameliorating endothelial dysfunction.

METTL3-METTL14 complex induces necroptosis and inflammation of vascular smooth muscle cells via promoting N6 methyladenosine mRNA methylation of receptor-interacting protein 3 in abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) have the highest incidence and rupture rate of all aortic aneurysms. The N6 methyladenosine (m6A) modification is closely associated with angiotensin (Ang II)-induced aortic diseases. This study aimed to identify whether the m6A writer METTL3/METTL4 regulates rip3 mRNA expression in AAA. To induce the mouse AAA model, apolipoprotein E-deficient (ApoE-/-) mice were subcutaneously infused with Ang II, and C57BL/6 mice were infused with type I elastase. Vascular smooth muscle cells (VSMCs) were induced with Ang II. Necroptosis was detected using an Annexin V-FITC/PI apoptosis detection kit, and ELISA assays measured inflammatory cytokines. The RNA immunoprecipitation-qPCR determined the methylated rip3 mRNA level. The increased expressions of inflammatory factors, aortic adventitia injury, degradation of elastin, and CD68-positive cells suggested the successful establishment of mouse AAA models. In AAA aorta wall tissues, the m6A modification level and the expression of METTL3/METTL14 were elevated. In Ang II-induced VSMCs, necroptosis and inflammatory cytokines in the supernatants were increased. RNA immunoprecipitation and co-immunoprecipitation assays confirmed the binding between the METTL3-METTL14 complex and rip3 mRNA, the interaction between YTHDF3 and rip3 mRNA, and between the METTL3-METTL14 complex and SMAD2/3. Interference with METTL3/METTL14 attenuated VSMC necroptosis, inflammatory response, and the AAA pathological process in vivo. The METTL3-METTL14 complex, which was increased by the activation of the SMAD2/3, elevated the m6A modification of rip3 mRNA by promoting the binding between YTHDF3 and rip3 mRNA, thus contributing to the progression of AAA. The activation of SMAD2/3 in VSMCs of abdominal aortic wall tissues is stimulated by Ang II. Subsequently, it promotes METTL3 METTL14 complex mediated m6A modification of rip3 mRNA. Meanwhile, the level of rip3 mRNA becomes more stable under the m6A reader of YTHDF3, which increases the protein level of RIP3 and further induces VSMC necroptosis. In addition, cell debris induces inflammatory factors in neighboring VSMCs and recruit monocytes/macrophages to the lesion.

Dysregulations of Key Regulators of Angiogenesis and Inflammation in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a chronic vascular disease caused by localized weakening and broadening of the abdominal aorta. AAA is a clearly underdiagnosed disease and is burdened with a high mortality rate (65-85%) from AAA rupture. Studies indicate that abnormal regulation of angiogenesis and inflammation contributes to progression and onset of this disease; however, dysregulations in the molecular pathways associated with this disease are not yet fully explained. Therefore, in our study, we aimed to identify dysregulations in the key regulators of angiogenesis and inflammation in patients with AAA in peripheral blood mononuclear cells (using qPCR) and plasma samples (using ELISA). Expression levels of ANGPT1, CXCL8, PDGFA, TGFB1, VEGFB, and VEGFC and plasma levels of TGF-alpha, TGF-beta 1, VEGF-A, and VEGF-C were found to be significantly altered in the AAA group compared to the control subjects without AAA. Associations between analyzed factors and risk factors or biochemical parameters were also explored. Any of the analyzed factors was associated with the size of the aneurysm. The presented study identified dysregulations in key angiogenesis- and inflammation-related factors potentially involved in AAA formation, giving new insight into the molecular pathways involved in the development of this disease and providing candidates for biomarkers that could serve as diagnostic or therapeutic targets.

Ketosis Prevents Abdominal Aortic Aneurysm Rupture Through C-C Chemokine Receptor Type 2 Downregulation and Enhanced MMP Balance

Abdominal aortic aneurysms (AAAs) are prevelant with aging, and AAA rupture is associated with high mortality. There is currently no effective medical therapy for AAA rupture. Previous work demonstrated that the monocyte chemoattractant protein (MCP-1) / C-C chemokine receptor type 2 (CCR2) axis critically regulates AAA inflammation, matrix-metalloproteinase (MMP) production, and extracellular matrix (ECM) stability. Here we similarly observed that Ccr2-/- mice have significantly reduced AAA expansion and rupture. We therefore hypothesized that a dietary modulation of the CCR2 axis may therapeutically impact AAA risk of rupture. Since ketone bodies (KBs) can trigger repair mechanisms in response to inflammation, we specifically evaluated whether systemic ketosis in vivo can reduce CCR2 and AAA progression. Male Sprague-Dawley rats underwent surgical AAA formation using porcine pancreatic elastase (PPE), and received daily β-aminopropionitrile (BAPN) to promote AAA rupture. Animals with AAAs received either a standard diet (SD), ketogenic diet (KD), or exogenous KBs (EKB). Animals recieving KD and EKB reached a state of ketosis, and had significant reduction in AAA expansion and incidence of rupture. Ketosis also led to significantly reduced aortic CCR2 content, improved MMP balance, and reduced ECM degradation. In summary, this study demonstrates that ketosis plays a crucial role in AAA pathobiology, and provides the impetus for future clinical studies investigating the potential benefit of ketosis for prevention of AAA expansion and rupture.

Genetic deficiency of protein inhibitor of activated STAT3 suppresses experimental abdominal aortic aneurysms

Aim

Signal transducer and activator of transcription (STAT) signaling is critical for the pathogenesis of abdominal aortic aneurysms (AAAs). Though protein inhibitor of activated STAT3 (PIAS3) negatively modulates STAT3 activity, but its role in AAA disease remains undefined.

Method

AAAs were induced in PIAS3 deficient (PIAS3−/−) and wild type (PIAS3+/+) male mice via transient intra-aortic elastase infusion. AAAs were assessed by in situ measurements of infrarenal aortic external diameters prior to (day 0) and 14 days after elastase infusion. Characteristic aneurysmal pathologies were evaluated by histopathology.

Results

Fourteen days following elastase infusion, aneurysmal aortic diameter was reduced by an approximately 50% in PIAS3−/− as compared to PIAS3+/+ mice. On histological analyses, PIAS3−/− mice showed less medial elastin degradation (media score: 2.5) and smooth muscle cell loss (media score: 3.0) than those in PIAS3+/+ mice (media score: 4 for both elastin and SMC destruction). Aortic wall leukocyte accumulation including macrophages, CD4+ T cells, CD8+ T cells and B cells as well as mural neovessel formation were significantly reduced in PIAS3−/− as compared to PIAS3+/+ mice. Additionally, PIAS3 deficiency also downregulated the expression levels of matrix metalloproteinases 2 and 9 by 61% and 70%, respectively, in aneurysmal lesion.

Conclusion

PIAS3 deficiency ameliorated experimental AAAs in conjunction with reduced medial elastin degradation and smooth muscle cell depletion, mural leukocyte accumulation and angiogenesis.

Structural dysregulation of the pulmonary autograft was associated with a greater density of p16INK4A-vascular smooth muscle cells

The present study tested the hypothesis that a senescent phenotype of vascular smooth muscle cells (VSMCs) may represent the seminal event linked to maladaptive pulmonary autograft remodeling of a small number of patients that underwent the Ross procedure. The diameter of the pulmonary autograft (47±4 mm) of three male patients was significantly greater compared to the pulmonary artery (26±1 mm) excised from bicuspid aortic valve (BAV) patients. The pulmonary autograft was associated with a neointimal region and the adjacent medial region was significantly thinner compared to the pulmonary artery of BAV patients. Structural dysregulation was evident as elastin content of the medial region was significantly reduced in the pulmonary autograft compared to the pulmonary artery of BAV patients. By contrast, collagen content of the medial region of the pulmonary autograft and the pulmonary artery of BAV patients was not significantly different. Reduced medial elastin content of the pulmonary autograft was associated with increased protein levels of matrix metalloproteinase-9. The latter phenotype was not attributed to a robust inflammatory response as the percentage of Mac-2⁽⁺⁾-infiltrating monocytes/macrophages was similar between groups. A senescent phenotype was identified as protein levels of the cell cycle inhibitor p27^kip1 were upregulated and the density of p16^INK4A/non-muscle myosin IIB⁽⁺⁾-VSMCs was significantly greater in the pulmonary autograft compared to the pulmonary artery of BAV patients. Thus, senescent VSMCs may represent the predominant cellular source of increased matrix metalloproteinase-9 protein expression translating to maladaptive pulmonary autograft remodeling characterized by elastin degradation, medial thinning and neointimal formation.

Cordycepin suppresses vascular inflammation, apoptosis and oxidative stress of arterial smooth muscle cell in thoracic aortic aneurysm with VEGF inhibition

BACKGROUND

Thoracic aortic aneurysm (TAA) is a type of common and serious vascular disease, in which inflammation, apoptosis and oxidative stress are strongly involved in the progression. Cordycepin, a bioactive compound from Cordyceps militaris, exhibits anti-inflammatory and anti-oxidative activities. This study aimed to address the role and mechanism of cordycepin in TAA.

METHODS

The thoracic aortas were perivascularly administrated with calcium chloride (CaCl₂), and human aortic smooth muscle cells (HASMCs) were incubated with angiotensin II (Ang II) to simulate the TAA model in vivo and in vitro, respectively. The effect and mechanism of cordycepin in TAA were explored by hematoxylin and eosin (HE) staining, immunohistochemistry (IHC), immunofluorescence (IF), western blot, biochemical test, cell counting kit-8 (CCK-8), and terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) assays.

RESULTS

Cordycepin improved the CaCl₂-induced the aneurysmal alteration and disappearance of normal wavy elastic structures of the aorta tissues, TAA incidence and thoracic aortic diameter in rats, and Ang II-induced the cell viability of HASMCs. Cordycepin reversed the CaCl₂-induced the relative protein expression of cleaved caspase 9, cleaved caspase 3, interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-1β, and the relative levels of glutathione (GSH), malonaldehyde (MDA) and reactive oxygen species (ROS) in vivo, or Ang II-induced these changes in vitro. Mechanically, cordycepin reduced the relative protein expressions of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), cluster of differentiation 31 (CD31) and endothelial nitric oxide synthase (eNOS) in the Ang II-induced HASMCs. Correspondingly, overexpression of VEGF increased the levels of the indicators involved in apoptosis, inflammation and oxidative stress, which were antagonized with the cordycepin incubation in the Ang II-induced HASMCs.

CONCLUSION

Cordycepin inhibited apoptosis, inflammation and oxidative stress of TAA through the inhibition of VEGF.

Ketosis Prevents Abdominal Aortic Aneurysm Rupture Through CCR2 Downregulation and Enhanced MMP Balance

Abdominal aortic aneurysms (AAAs) are common in aging populations, and AAA rupture is associated with high morbidity and mortality. There is currently no effective medical preventative therapy for AAAs to avoid rupture. It is known that the monocyte chemoattractant protein (MCP-1) / C-C chemokine receptor type 2 (CCR2) axis critically regulates AAA tissue inflammation, matrix-metalloproteinase (MMP) production, and in turn extracellular matrix (ECM) stability. However, therapeutic modulation of the CCR2 axis for AAA disease has so far not been accomplished. Since ketone bodies (KBs) are known to trigger repair mechanisms in response to vascular tissue inflammation, we evaluated whether systemic in vivo ketosis can impact CCR2 signaling, and therefore impact AAA expansion and rupture. To evaluate this, male Sprague-Dawley rats underwent surgical AAA formation using porcine pancreatic elastase (PPE), and received daily β-aminopropionitrile (BAPN) to promote AAA rupture. Animals with formed AAAs received either a standard diet (SD), ketogenic diet (KD), or exogenous KB supplements (EKB). Animals that received KD and EKB reached a state of ketosis, and had significantly reduced AAA expansion and incidence of rupture. Ketosis also led to significantly reduced CCR2, inflammatory cytokine content, and infiltrating macrophages in AAA tissue. Additionally, animals in ketosis had improved balance in aortic wall matrix-metalloproteinase (MMP), reduced extracellular matrix (ECM) degradation, and higher aortic media Collagen content. This study demonstrates that ketosis plays an important therapeutic role in AAA pathobiology, and provides the impetus for future studies investigating the role of ketosis as a preventative strategy for individuals with AAAs.

A machine learning-derived gene signature for assessing rupture risk and circulatory immunopathologic landscape in patients with intracranial aneurysms

Background

Intracranial aneurysm (IA) is an uncommon but severe subtype of cerebrovascular disease, with high mortality after aneurysm rupture. Current risk assessments are mainly based on clinical and imaging data. This study aimed to develop a molecular assay tool for optimizing the IA risk monitoring system.

Methods

Peripheral blood gene expression datasets obtained from the Gene Expression Omnibus were integrated into a discovery cohort. Weighted gene co-expression network analysis (WGCNA) and machine learning integrative approaches were utilized to construct a risk signature. QRT-PCR assay was performed to validate the model in an in-house cohort. Immunopathological features were estimated using bioinformatics methods.

Results

A four-gene machine learning-derived gene signature (MLDGS) was constructed for identifying patients with IA rupture. The AUC of MLDGS was 1.00 and 0.88 in discovery and validation cohorts, respectively. Calibration curve and decision curve analysis also confirmed the good performance of the MLDGS model. MLDGS was remarkably correlated with the circulating immunopathologic landscape. Higher MLDGS scores may represent higher abundance of innate immune cells, lower abundance of adaptive immune cells, and worse vascular stability.

Conclusions

The MLDGS provides a promising molecular assay panel for identifying patients with adverse immunopathological features and high risk of aneurysm rupture, contributing to advances in IA precision medicine.

Type I Interferon Receptor Subunit 1 Deletion Attenuates Experimental Abdominal Aortic Aneurysm Formation

Objective: Type I interferon receptor signaling contributes to several autoimmune and vascular diseases such as lupus, atherosclerosis and stroke. The purpose of this study was to assess the influence of type I interferon receptor deficiency on the formation and progression of experimental abdominal aortic aneurysms (AAAs). Methods: AAAs were induced in type I interferon receptor subunit 1 (IFNAR1)-deficient and wild type control male mice via intra-infrarenal aortic infusion of porcine pancreatic elastase. Immunostaining for IFNAR1 was evaluated in experimental and clinical aneurysmal abdominal aortae. The initiation and progression of experimental AAAs were assessed via ultrasound imaging prior to (day 0) and days 3, 7 and 14 following elastase infusion. Aneurysmal histopathology was analyzed at sacrifice. Results: Increased aortic medial and adventitial IFNAR1 expression was present in both clinical AAAs harvested at surgery and experimental AAAs. Following AAA induction, wild type mice experienced progressive, time-dependent infrarenal aortic enlargement. This progression was substantially attenuated in IFNAR1-deficient mice. On histological analyses, medial elastin degradation, smooth muscle cell depletion, leukocyte accumulation and neoangiogenesis were markedly diminished in IFNAR1-deficient mice in comparison to wild type mice. Conclusion: IFNAR1 deficiency limited experimental AAA progression in response to intra-aortic elastase infusion. Combined with clinical observations, these results suggest an important role for IFNAR1 activity in AAA pathogenesis.

Transcriptome-Based Dissection of Intracranial Aneurysms Unveils an “Immuno-Thermal” Microenvironment and Defines a Pathological Feature-Derived Gene Signature for Risk Estimation

Immune inflammation plays an essential role in the formation and rupture of intracranial aneurysm (IA). However, the current limited knowledge of alterations in the immune microenvironment of IA has hampered the mastery of pathological mechanisms and technological advances, such as molecular diagnostic and coated stent-based molecular therapy. In this study, seven IA datasets were enrolled from the GEO database to decode the immune microenvironment and relevant biometric alterations. The ssGSEA algorithm was employed for immune infiltration assessment. IAs displayed abundant immune cell infiltration, activated immune-related pathways, and high expression of immune-related genes. Several immunosuppression cells and genes were also coordinately upregulated in IAs. Five immune-related hub genes, including CXCL10, IL6, IL10, STAT1, and VEGFA, were identified from the protein-protein interaction network and further detected at the protein level. CeRNA networks and latent drugs targeting the hub genes were predicted for targeted therapy reference. Two gene modules recognized via WCGNA were functionally associated with contractile smooth muscle loss and extracellular matrix metabolism, respectively. In blood datasets, a pathological feature-derived gene signature (PFDGS) for IA diagnosis and rupture risk prediction was established using machine learning. Patients with high PFDGS scores may possess adverse biological alterations and present with a high risk of morbidity or IA rupture, requiring more vigilance or prompt intervention. Overall, we systematically unveiled an “immuno-thermal” microenvironment characterized by co-enhanced immune activation and immunosuppression in IA, which provides a novel insight into molecular pathology. The PFDGS is a promising signature for optimizing risk surveillance and clinical decision-making in IA patients.

Carotid artery vasoreactivity correlates with abdominal aortic vasoreactivity in young healthy individuals but not in patients with abdominal aortic aneurysm

Background

Sympathetic stimulation of central arteries, such as coronary and carotid arteries, cause vasodilation in healthy subjects, but vasoconstriction in those with increased cardiovascular risk. This study compared vasoreactivity to sympathetic stimulation between abdominal aorta and carotid artery in healthy young individuals (young group, n = 20), in patients with abdominal aortic aneurysm (AAA group, n = 20) and in a healthy older group, age- and gender matched with AAA group (matched group, n = 18).

Method

All subjects underwent cold pressor test, while performing concomitantly duplex ultrasound of abdominal aorta and carotid artery vasoreactivity. Observer-independent software was used to analyze and calculate magnitude and timing of maximum vasodilation or vasoconstriction. Pearson's correlation coefficient was calculated to investigate vasoreactivity between arteries.

Results

Carotid artery reactivity [Interquartile range 25%, Interquartile range 75%] did not significantly differ between the young, matched and AAA group (3.5% [1.4, 4.7], 2.6% [2.0, 4.1] and 2.2% [-1.9, 3.7], respectively, p = 0.301). Abdominal aortic responsiveness demonstrated larger differences between young (4.9% [-0.2, 8.4]), matched (3.3% [-2.5, 4.4]) and individuals with AAA (0.5% [-3.9, 4.1], p = 0.059). Pooled analysis showed a significant correlation between carotid and abdominal aortic vasoreactivity (r = 0.444, p = 0.001). Subgroup analyses demonstrated significant correlation between both arteries in young (r = 0.636, p = 0.003), but not matched (r = −0.040, p = 0.866) or AAA group (r = 0.410, p = 0.129).

Conclusions

Sympathetic stimulation induces powerful vasodilation of the carotid artery and abdominal aorta, which is significantly correlated in healthy individuals. No such correlation is present in abdominal aortic aneurysm patients. This suggests the aneurysm alters local abdominal aorta vasoreactivity, but not the carotid artery.

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Vasoreactivity is significantly correlated between carotid and abdominal aorta.

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Presence of abdominal aneurysm was associated with local impaired vasoreactivity.

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Abdominal aorta demonstrates a stronger vasoreactivity than the carotid artery.

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Vasoreactivity of the carotid artery did not differ between groups.

miR-424/322 protects against abdominal aortic aneurysm formation by modulating the Smad2/3/runt-related transcription factor 2 axis

Rupture of abdominal aortic aneurysms (AAAs) is one of the leading causes of sudden death in the elderly population. The osteogenic transcription factor runt-related gene (RUNX) encodes multifunctional mediators of intracellular signal transduction pathways in vascular remodeling and inflammation. We aimed to evaluate the roles of RUNX2 and its putative downstream target miR-424/322 in the modulation of several AAA progression-related key molecules, such as matrix metalloproteinases and vascular endothelial growth factor. In the GEO database, we found that male patients with AAAs had higher RUNX2 expression than did control patients. Several risk factors for aneurysm induced the overexpression of MMPs through RUNX2 transactivation, and this was dependent on Smad2/3 upregulation in human aortic smooth muscle cells. miR-424 was overexpressed through RUNX2 after angiotensin II (AngII) challenge. The administration of siRUNX2 and miR-424 mimics attenuated the activation of the Smad/RUNX2 axis and the overexpression of several AAA progression-related molecules in vitro. Compared to their littermates, miR-322 KO mice were susceptible to AngII-induced AAA, whereas the silencing of RUNX2 and the administration of exogenous miR-322 mimics ameliorated the AngII-induced AAA in ApoE KO mice. Overall, we established the roles of the Smad/RUNX2/miR-424/322 axis in AAA pathogenesis. We demonstrated the therapeutic potentials of miR-424/322 mimics and RUNX2 inhibitor for AAA progression.

Hypoxia Marker Carbonic Anhydrase IX Is Present in Abdominal Aortic Aneurysm Tissue and Plasma

Abdominal aortic aneurysms (AAA) are a significant cause of premature deaths worldwide. Since there is no specific treatment for reducing AAA progression, it is crucial to understand the pathogenesis leading to aneurysm wall weakening/remodeling and identify new proteins involved in this process which could subsequently serve as novel therapeutic targets. In this study, we analyzed the presence of the hypoxia-related proteins carbonic anhydrase IX (CA IX), hypoxia-inducible factor 1α (HIF-1α), and AKT as the key molecule in the phosphoinositide-3-kinase pathway in the AAA wall. Additionally, we used a blood-based assay to examine soluble CA IX (s-CA IX) levels in the plasma of AAA patients. Using western blotting, we detected CA IX protein in 12 out of 15 AAA tissue samples. Immunohistochemistry staining proved CA IX expression in the media of the aneurysmal wall. Evaluation of phosphorylated (p-AKT) and total AKT showed elevated levels of both forms in AAA compared to normal aorta. Using ELISA, we determined the concentration of s-CA IX >20 pg/mL in 13 out of 15 AAA patients. Results obtained from in silico analysis of CA9 and aneurysm-associated genes suggest a role for CA IX in aneurysmal wall remodeling. Our results prove the presence of hypoxia-related CA IX in AAA tissues and indicate a possible role of CA IX in hypoxia-associated cardiovascular diseases.

New Insights Into the Role of Mitochondria Quality Control in Ischemic Heart Disease

IHD is a significant cause of mortality and morbidity worldwide. In the acute phase, it's demonstrated as myocardial infarction and ischemia-reperfusion injury, while in the chronic stage, the ischemic heart is mainly characterised by adverse myocardial remodelling. Although interventions such as thrombolysis and percutaneous coronary intervention could reduce the death risk of these patients, the underlying cellular and molecular mechanisms need more exploration. Mitochondria are crucial to maintain the physiological function of the heart. During IHD, mitochondrial dysfunction results in the pathogenesis of ischemic heart disease. Ischemia drives mitochondrial damage not only due to energy deprivation, but also to other aspects such as mitochondrial dynamics, mitochondria-related inflammation, etc. Given the critical roles of mitochondrial quality control in the pathological process of ischemic heart disease, in this review, we will summarise the efforts in targeting mitochondria (such as mitophagy, mtROS, and mitochondria-related inflammation) on IHD. In addition, we will briefly revisit the emerging therapeutic targets in this field.

Treatment with the Prolyl Hydroxylase Inhibitor JNJ Promotes Abdominal Aortic Aneurysm Progression in Diabetic Mice

OBJECTIVE

Prolyl hydroxylase domain containing proteins (PHD) rigorously regulate intracellular hypoxia inducible factor-1 (HIF-1) protein expression and activity. Diabetes impairs PHD activity and attenuates abdominal aortic aneurysm (AAA) progression. The extent to which dysregulated PHD activity contributes to diabetes mediated AAA suppression remains undetermined.

METHODS

AAAs were induced in diabetic and non-diabetic male C57BL/6J mice via intra-aortic elastase infusion. A PHD inhibitor (JNJ-42041935, aka "JNJ", 150 mmol/kg) or vehicle alone was administered daily starting one day prior to AAA induction for 14 days. Influences on AAA progression was assessed via ultrasonography and histopathology. Expression of aortic HIF-1α, three of its target genes and macrophage derived mediators were assayed via quantitative reverse transcription polymerase chain reaction. Aneurysmal sections from AAA patients with and without diabetes (two patients in each group) were immunostained for HIF-1α and vascular endothelial growth factor (VEGF)-A.

RESULTS

Expression of HIF-1α target genes (erythropoietin, VEGF-A, and glucose transporter-1) was reduced by 45% - 95% in experimental diabetic aortas. Diameter enlargement was similarly limited, as were mural elastin degradation, leukocyte infiltration, and neo-angiogenesis (reduced capillary density and length) on histopathology. Pre-treatment with JNJ prior to AAA initiation augmented aortic HIF-1α target gene expression and aneurysm progression in diabetic mice, along with macrophage VEGF-A and matrix metalloproteinase 2 mRNA expression. No differences were noted in HIF-1α or VEGF-A expression on aortic immunohistochemical staining of human aortic tissue as a function of diabetes status.

CONCLUSION

Small molecule PHD inhibitor treatment reduces or offsets impairment of experimental AAA progression in hyperglycemic mice, highlighting the potential contribution of dysregulated PHD activity to diabetes mediated aneurysm suppression.

A reduction in the vascular smooth muscle cell focal adhesion component syndecan-4 is associated with abdominal aortic aneurysm formation

BACKGROUND

Abdominal aortic aneurysm (AAA) is a serious vascular disease for which there is no effective drug treatment. The incidence of AAA increases significantly as a subject ages, and the molecular mechanism of AAA formation remains elusive. In the present study, we investigated the role of syndecan-4 (SDC4), an important component of focal adhesions, in AAA formation and its association with phenotypic changes in vascular smooth muscle cells (VSMCs).

METHODS AND RESULTS

The protein expression levels of SDC4 were significantly decreased in human AAA tissue and those of an AAA mouse model. Moreover, SDC4 knockout (KO) in mice accelerated the formation and rupture of AAAs induced by angiotensin II (Ang II) and calcium chloride (CaCl2 ) Mechanistically, the decrease in SDC4 led to the transformation of cultured VSMCs from a contractile to a secretory phenotype. The RhoA-F/G-actin-myocardin-related transcription factor-A (MRTF-A) signalling pathway was shown to be involved in SDC4-dependent VSMC alteration. Sphingosine-1-phosphate (S1P), a G-protein-coupled receptor, attenuated the AAA formation in SDC4-KO and wild-type (WT) mice in response to Ang II and CaCl2 stimulation.

CONCLUSION

We herein demonstrated that silencing SDC4 was associated with increased AAA formation and phenotypic changes in VSMCs via the RhoA-F/G-actin-MRTF-A pathway. These findings indicated that a reduction in SDC4 expression was an important pathological alteration and potential therapeutic target for AAA formation.

Knockdown of long noncoding RNA GAS5 reduces vascular smooth muscle cell apoptosis by inactivating EZH2-mediated RIG-I signaling pathway in abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA), an irreversible cardiovascular disease prevalent in the artery, causes the increase of the aneurysm diameter over time, and is a fatal phenomenon inducing sidewall rupture. Long noncoding RNAs (lncRNAs) serve as promising biomarkers for AAA. In the present study, we sought to define the role of lncRNA growth-arrest-specific transcript 5 (GAS5) in growth of smooth muscle cells (SMC) and progression of AAA.

Methods

Initially, we established angiotensin II (Ang II)-induced AAA mouse models and Ang II-treated vascular SMC model. RT-qPCR and Western blot analysis were adopted to determine expression of GAS5 and zeste homolog 2 (EZH2). After ectopic expression and depletion experiments in Ang II-treated mice and vascular SMCs, cell apoptosis was detected in SMCs using flow cytometry and in mice using TUNEL staining. The binding of GAS5 and EZH2 was evaluated using RNA binding protein immunoprecipitation (RIP) and Co-IP assays.

Results

Increased GAS5 and RIG-I but decreased EZH2 were found in aortic tissues of AAA mice. EZH2 overexpression inhibited AAA formation and suppressed SMC apoptosis. Functionally, EZH2 blocked the RIG-I signaling pathway and consequently inhibited SMC apoptosis. GAS5 regulated EZH2 transcription in a negative manner in SMCs. Knockdown of GAS5 attenuated SMC apoptosis, which was reversed by EZH2 inhibition or RIG-I overexpression.

Conclusions

The current study demonstrated that GAS5 induced SMC apoptosis and subsequent AAA onset by activating EZH2-mediated RIG-I signaling pathway, highlighting GAS5 as a novel biomarker for AAA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03023-w.

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.

Traditional Chinese Medicine Intervenes Ventricular Remodeling Following Acute Myocardial Infarction: Evidence From 40 Random Controlled Trials With 3,659 Subjects

Objectives: We intend to conduct a meta-analysis on the systematic evaluation of traditional Chinese medicine (TCM) in the treatment of ventricular remodeling following acute myocardial infarction (AMI). Our findings may provide certain references for the clinical treatment of ventricular remodeling.

Methods: A systematic literature search was conducted in PubMed, Web of Science, Cochrane Library, Embase, CNKI, Wanfang Data, CQVIP, and CBM before 20 July 2020. Data were analyzed using a random/fixed-effect model. Primary outcomes included the effectiveness and TCM syndrome score (TCMSS). Secondary outcomes included 1) echocardiography data, including the left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular end-diastolic volume index (LVEDVi), left ventricular end-systolic volume index (LVESVi), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), interventricular septum thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular ejection fraction (LVEF), E/A, stroke volume (SV), and wall motion score (WMS); 2) serum indicators, including the B-type natriuretic peptide (BNP) or N-terminal pro-B-type natriuretic peptide (NT-proBNP), and C-reactive protein (CRP) or high sensitivity CRP (hs-CRP); (3) major adverse cardiovascular events (MACE) and other adverse events

Results: Forty RCTs involving 3,659 subjects were recruited. Our findings proved that a combination of TCM or TCM preparations with conventional Western medicine for preventing and reversing ventricular remodeling at post-AMI could remarkably enhance the total effectiveness and reduced TCMSS. Moreover, myocardial functions (LVEF, E/A, and SV), ventricular remodeling (LVEDVi, LVESVi, LVEDV, LVESV, LVEDD, LVESD, LVPWT, and WMS), serum levels of BNP and CRP, and MACE were significantly improved by the combination of TCM or TCM preparations with conventional Western medicine. Nevertheless, IVST and the incidence of other adverse events were comparable between control and experimental groups

Conclusion: The combination of TCM or TCM preparations and conventional Western medicine can alleviate the process of ventricular remodeling, enhance cardiac function, and reduce the incidence of MACE in AMI patients.

Recombinant Interleukin-19 Suppresses the Formation and Progression of Experimental Abdominal Aortic Aneurysms

Background Interleukin-19 is an immunosuppressive cytokine produced by immune and nonimmune cells, but its role in abdominal aortic aneurysm (AAA) pathogenesis is not known. This study aimed to investigate interleukin-19 expression in, and influences on, the formation and progression of experimental AAAs. Methods and Results Human specimens were obtained at aneurysm repair surgery or from transplant donors. Experimental AAAs were created in 10- to 12-week-old male mice via intra-aortic elastase infusion. Influence and potential mechanisms of interleukin-19 treatment on AAAs were assessed via ultrasonography, histopathology, flow cytometry, and gene expression profiling. Immunohistochemistry revealed augmented interleukin-19 expression in both human and experimental AAAs. In mice, interleukin-19 treatment before AAA initiation via elastase infusion suppressed aneurysm formation and progression, with attenuation of medial elastin degradation, smooth-muscle depletion, leukocyte infiltration, neoangiogenesis, and matrix metalloproteinase 2 and 9 expression. Initiation of interleukin-19 treatment after AAA creation limited further aneurysmal degeneration. In additional experiments, interleukin-19 treatment inhibited murine macrophage recruitment following intraperitoneal thioglycolate injection. In classically or alternatively activated macrophages in vitro, interleukin-19 downregulated mRNA expression of inducible nitric oxide synthase, chemokine C-C motif ligand 2, and metalloproteinases 2 and 9 without apparent effect on cytokine-expressing helper or cytotoxic T-cell differentiation, nor regulatory T cellularity, in the aneurysmal aorta or spleen of interleukin-19-treated mice. Interleukin-19 also suppressed AAAs created via angiotensin II infusion in hyperlipidemic mice. Conclusions Based on human evidence and experimental modeling observations, interleukin-19 may influence the development and progression of AAAs.

Erythropoietin promotes abdominal aortic aneurysms in mice through angiogenesis and inflammatory infiltration

Abdominal aortic aneurysm (AAA) is a potentially fatal vascular disease, but the underlying mechanisms remain unknown. Here, we tested the hypothesis that erythropoietin (EPO) may promote the formation of AAA. We found that EPO dose-dependently promoted the formation of AAA in both Apoe ^-/- (66.7%) and wild-type (WT) (60%) mice receiving a high dose of EPO. EPO monoclonal antibodies given to Apoe ^-/- mice receiving angiotensin II (AngII) stimulation resulted in a markedly lower incidence of AAA (from 86.7 to 20%, P < 0.001), and EPO receptor (EPOR) knockdown in Epor ^+/- Apoe ^-/- mice substantially reduced the incidence of AAA compared to Apoe ^-/- mice after AngII stimulation (from 86.7 to 45.5%, P < 0.05), further supporting the finding that EPO is a contributor to AAA formation. EPO-induced AAA resulted in increased microvessels, phagocyte infiltration, and matrix metalloproteinase secretion, as well as reduced collagen and smooth muscle cells (SMCs). Experiments in vitro and ex vivo demonstrated that EPO induced proliferation, migration, and tube formation of endothelial cells via the JAK2/STAT5 signaling pathway. In humans, serum EPO concentrations were higher in patients with AAA than in healthy individuals and correlated with the size of the AAA, suggesting a potential link between EPO and the severity of AAA in humans. In conclusion, we found that EPO promotes the formation of AAA in both Apoe ^-/- and WT mice by enhancing angiogenesis, inflammation, collagen degradation, and apoptosis of SMCs and that EPO/EPOR signaling is essential for AngII-induced AAA. The association between EPO and AAA in humans warrants further study.

Pathophysiological Aspects of the Development of Abdominal Aortic Aneurysm with a Special Focus on Mitochondrial Dysfunction and Genetic Associations

Abdominal aortic aneurysm (AAA) is a complex degenerative vascular disease, with considerable morbidity and mortality rates among the elderly population. The mortality of AAA is related to aneurysm expansion (the enlargement of the aortic diameter up to 30 mm and above) and the subsequent rupture. The pathogenesis of AAA involves several biological processes, including aortic mural inflammation, oxidative stress, vascular smooth muscle cell apoptosis, elastin depletion, and degradation of the extracellular matrix. Mitochondrial dysfunction was also found to be associated with AAA formation. The evidence accumulated to date supports a close relationship between environmental and genetic factors in AAA initiation and progression. However, a comprehensive pathophysiological understanding of AAA formation remains incomplete. The open surgical repair of AAA is the only therapeutic option currently available, while a specific pharmacotherapy is still awaited. Therefore, there is a great need to clarify pathophysiological cellular and molecular mechanisms underlying AAA formation that would help to develop effective pharmacological therapies. In this review, pathophysiological aspects of AAA development with a special focus on mitochondrial dysfunction and genetic associations were discussed.

Vasohibin-2 Aggravates Development of Ascending Aortic Aneurysms but not Abdominal Aortic Aneurysms nor Atherosclerosis in ApoE-Deficient Mice

BACKGROUND

Vasohibin-2 (VASH2) has been isolated as a homologue of vasohibin-1 (VASH1) that promotes angiogenesis counteracting with VASH1. Chronic angiotensin II (AngII) infusion promotes both ascending and abdominal aortic aneurysms (AAs) in mice. The present study aimed to investigate whether exogenous VASH2 influenced AngII-induced vascular pathology in apolipoprotein E-deficient (ApoE-/-) mice.

METHODS

Male, ApoE-/- mice (9-14 weeks old) were injected with Ad LacZ or Ad VASH2. After a week, saline or AngII (1,000 ng/kg/minute) was infused into the mice subcutaneously via mini-osmotic pumps for 3 weeks. Consequently, all these mice were divided into 4 groups: saline + LacZ (n = 5), saline + VASH2 (n = 5), AngII + LacZ (n = 18), and AngII + VASH2 (n = 17).

RESULTS

Exogenous VASH2 had no significant effect on ex vivo maximal diameters of abdominal aortas (AngII + LacZ: 1.67 ± 0.17 mm, AngII + VASH2: 1.52 ± 0.16 mm, n.s.) or elastin fragmentation and accumulation of inflammatory cells. Conversely, exogenous VASH2 significantly increased intima areas of aortic arches (AngII + LacZ: 16.6 ± 0.27 mm2, AngII + VASH2: 18.6 ± 0.64 mm2, P = 0.006). VASH2 effect of AngII-induced ascending AAs was associated with increased cleaved caspase-3 abundance. AngII-induced atherosclerosis was not altered by VASH2.

CONCLUSIONS

The present study demonstrated that augmented VASH2 expression had no effect of AngII-induced abdominal AAs or atherosclerosis, while increasing dilation in the ascending aorta.

Importance of NLRP3 Inflammasome in Abdominal Aortic Aneurysms

Abdominal aortic aneurysm (AAA) is a chronic inflammatory degenerative aortic disease, which particularly affects older people. Nucleotide-binding oligomerization domain-like receptor family protein 3 (NLRP3) inflammasome is a multi-protein complex and mediates inflammatory responses by activating caspase 1 for processing premature interleukin (IL)-1β and IL-18. In this review, we first summarize the principle of NLRP3 inflammasome activation and the functionally distinct classes of small molecule NLRP3 inflammasome inhibitors. Next, we provide a comprehensive literature review on the expression of NLRP3 inflammasome effector mediators (IL-1β and IL-18) and components (caspase 1, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and NLRP3) in clinical and experimental AAAs. Finally, we discuss the influence of genetic deficiency or pharmacological inhibition of individual effector mediators and components of NLRP3 inflammasome on experimental AAAs. Accumulating clinical and experimental evidence suggests that NLRP3 inflammasome may be a promise therapeutic target for developing pharmacological strategies for clinical AAA management.

CaMKIIδ is upregulated by pro-inflammatory cytokine IL-6 in a JAK/STAT3-dependent manner to promote angiogenesis

Ca²⁺ /calmodulin-dependent protein kinase II (CaMKII) is a ubiquitous serine threonine kinase with established roles in physiological and pathophysiological vascular remodeling. Based on our previous study demonstrating that CaMKIIδ promotes thrombin-induced endothelial permeability and recent reports that CaMKII may contribute to inflammatory remodeling in the heart, we investigated CaMKIIδ-dependent regulation of endothelial function downstream of an interleukin-6 (IL-6)/JAK/STAT3 signaling axis. Upon treatment with IL-6 and its soluble receptor (sIL-6r), CaMKIIδ expression is significantly induced in HUVEC. Using pharmacological inhibitors of JAK and siRNA targeting STAT3, we demonstrated that activation of STAT3 is sufficient to induce CaMKIIδ expression. Under these conditions, rather than promoting IL-6-induced permeability, we found that CaMKIIδ promotes endothelial cell migration as measured by live cell imaging of scratch wound closure and single-cell motility analysis. In a similar manner, endothelial cell proliferation was attenuated upon knockdown of CaMKIIδ as determined by growth curves, cell cycle analysis, and capacitance of cell-covered electrodes as measured by ECIS. Using inducible endothelial-specific STAT3 knockout mice, we demonstrate that STAT3 signaling promotes developmental angiogenesis in the neonatal mouse retina assessed at postnatal day 6. CaMKIIδ expression in retinal endothelium was attenuated in these animals as measured by qPCR. STAT3's effects on angiogenesis were phenocopied by the endothelial-specific knockout of CaMKIIδ, with significantly reduced vascular outgrowth and number of junctions in the developing P6 retina. For the first time, we demonstrate that transcriptional regulation of CaMKIIδ by STAT3 promotes endothelial motility, proliferation, and in vivo angiogenesis.

Metformin Inhibits Abdominal Aortic Aneurysm Formation through the Activation of the AMPK/mTOR Signaling Pathway

BACKGROUND AND OBJECTIVE

Epidemiological evidence suggests that the antidiabetic drug metformin (MET) can also inhibit abdominal aortic aneurysm (AAA) formation. However, the underlying protective mechanism remains unknown. It has been reported that phosphorylated AMP-activated protein kinase (AMPK) levels are significantly lower in AAA tissues than control aortic tissues. AMPK activation can inhibit the downstream signaling molecule called mechanistic target of rapamycin (mTOR), which has also been reported be upregulated in thoracic aneurysms. Thus, blocking mTOR signaling could attenuate AAA progression. MET is a known agonist of AMPK. Therefore, in this study, we investigated if MET could inhibit formation of AAA by activating the AMPK/mTOR signaling pathway.

MATERIALS AND METHODS

The AAA animal model was induced by intraluminal porcine pancreatic elastase (PPE) perfusion in male Sprague Dawley rats. The rats were treated with MET or compound C (C.C), which is an AMPK inhibitor. AAA formation was monitored by serial ultrasound. Aortas were collected 4 weeks after surgery and subjected to immunohistochemistry, Western blot, and transmission electron microscopy analyses.

RESULTS

MET treatment dramatically inhibited the formation of AAA 4 weeks after PPE perfusion. MET reduced the aortic diameter, downregulated both macrophage infiltration and matrix metalloproteinase expression, decreased neovascularization, and preserved the contractile phenotype of the aortic vascular smooth muscle cells. Furthermore, we detected an increase in autophagy after MET treatment. All of these effects were reversed by the AMPK inhibitor C.C.

CONCLUSION

This study demonstrated that MET activates AMPK and suppresses AAA formation. Our study provides a novel mechanism for MET and suggests that MET could be potentially used as a therapeutic candidate for preventing AAA.

Decreased angiogenesis as a possible pathomechanism in cervical degenerative myelopathy

Endogenous immune mediated reactions of inflammation and angiogenesis are components of the spinal cord injury in patients with degenerative cervical myelopathy (DCM). The aim of this study was to identify alteration of certain mediators participating in angiogenetic and inflammatory reactions in patients with DCM. A consecutive series of 42 patients with DCM and indication for surgical decompression were enrolled for the study. 28 DCM patients were included, as CSF samples were taken preoperatively. We enrolled 42 patients requiring surgery for a thoracic abdominal aortic aneurysm (TAAA) as neurologically healthy controls. In 38 TAAA patients, CSF samples were taken prior to surgery and thus included. We evaluated the neurological status of patients and controls prior to surgery including NDI and mJOA. Protein-concentrations of factors with a crucial role in inflammation and angiogenesis were measured in CSF via ELISA testing (pg/ml): Angiopoietin 2, VEGF-A and C, RANTES, IL 1 beta and IL 8. Additionally, evaluated the status of the blood-spinal cord barrier (BSCB) by Reibers´diagnostic in all participants. Groups evidently differed in their neurological status (mJOA: DCM 10.1 ± 3.3, TAAA 17.3 ± 1.2, p < .001; NDI: DCM 47.4 ± 19.7, TAAA 5.3 ± 8.6, p < .001). There were no particular differences in age and gender distribution. However, we detected statistically significant differences in concentrations of mediators between the groups: Angiopoietin 2 (DCM 267.1.4 ± 81.9, TAAA 408.6 ± 177.1, p < .001) and VEGF C (DCM 152.2 ± 96.1, TAAA 222.4 ± 140.3, p = .04). DCM patients presented a mild to moderate BSCB disruption, controls had no signs of impairment. In patients with DCM, we measured decreased concentrations of angiogenic mediators. These results correspond to findings of immune mediated secondary harm in acute spinal cord injury. Reduced angiogenic activity could be a relevant part of the pathogenesis of DCM and secondary harm to the spinal cord.

Are activated B cells involved in the process of myocardial fibrosis after acute myocardial infarction? An in vivo experiment

BACKGROUND

Inflammatory cells infiltrate into the ischemic and hypoxic myocardial tissue after myocardial infarction. B cells gather at the site of myocardial injury and secrete cytokines to regulate immune inflammation and fiber repair processes.

METHODS

The animal experiment used ligation of the left anterior descending (LAD) artery of C57BL/6 mice to establish a mouse acute myocardial infarction (AMI) model to observe changes in activated B cells and cytokines at different time points. Twelve-week-old C57BL/6 male mice were randomly divided into the Sham group (24 mice) (thread under the LAD artery without ligation) and the AMI group (64 mice). In addition, C57BL/6 B-cell knockout (BKO) mice and C57BL/6 wild-type (WT) mice were used to establish AMI models to observe the expression levels of cardiomyocyte cytokines, such as TNF-α IL-1β, IL-6, TGF-β1, COL1-A1, COL3-AIII, TIMP, and MMP9. Moreover, pathological and collagen changes in the myocardium were analysed. One-way ANOVA and LSD method was used for comparisons of multiple and pairwise groups respectively. P < 0.05 indicated significant differences.

RESULTS

An AMI model of C57BL/6 mice was established successfully. The ratio of activated B cells and the expression of TNF-α, IL-1β, IL-6, TGF-β1, and B cell activating factor (BAFF) in the 5-day subgroup were the highest in the myocardium, spleen and peripheral blood with the most obvious myocardial inflammatory cell infiltration. The cytokines mRNA expression levels in the 5-day subgroup of the BKO group were decreased compared with those in the WT group (P < 0.05). Among the 2-week subgroups of the Sham, WT and BKO groups, the the LVEDd and LVESd of the BKO group were lower than those of the WT group (P < 0.05), and the left ventricular ejection fraction was higher than that of the WT group (P < 0.05).

CONCLUSION

Activated B cells participate in the sustained state of myocardial inflammation and immune system activation after AMI, and may affect the metabolism of myocardial collagen after AMI by secreting cytokines. Moreover, B cells promote the expression of myocardial collagen Type I and Type III and damage the left ventricular ejection function.

Relationships Between Perivascular Adipose Tissue and Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) are typically asymptomatic, and there is a high mortality rate associated with aneurysm rupture. AAA pathogenesis involves extracellular matrix degradation, vascular smooth muscle cell phenotype switching, inflammation, and oxidative stress. There is increasing evidence of excessive adipocyte accumulation in ruptured AAA walls. These excessive numbers of adipocytes in the vascular wall have been closely linked with AAA progression. Perivascular adipose tissue (PVAT), a unique type of adipose tissue, can be involved in adipocyte accumulation in the AAA wall. PVAT produces various chemokines and adipocytokines around vessels to maintain vascular homeostasis through paracrine and autocrine mechanisms in normal physiological conditions. Nevertheless, PVAT loses its normal function and promotes the progression of vascular diseases in pathological conditions. There is evidence of significantly reduced AAA diameter in vessel walls of removed PVAT. There is a need to highlight the critical roles of cytokines, cells, and microRNA derived from PVAT in the regulation of AAA development. PVAT may constitute an important therapeutic target for the prevention and treatment of AAAs. In this review, we discuss the relationship between PVAT and AAA development; we also highlight the potential for PVAT-derived factors to serve as a therapeutic target in the treatment of AAAs.

Daphnetin suppresses experimental abdominal aortic aneurysms in mice via inhibition of aortic mural inflammation

Rupture of abdominal aortic aneurysm (AAA) is a devastating event that can be prevented by inhibiting the growth of small aneurysms. Therapeutic strategies targeting certain events that promote the development of AAA must be developed, in order to alter the course of AAA. Chronic inflammation of the aortic mural is a major characteristic of AAA and is related to AAA formation, development and rupture. Daphnetin (DAP) is a coumarin derivative with anti-inflammatory properties that is extracted from Daphne odora var. However, the effect of DAP on AAA development remains unclear. The present study investigated the effect of DAP on the formation and development of experimental AAAs and its potential underlying mechanisms. A mice AAA model was established by intra-aortic infusion of porcine pancreatic elastase (PPE), and mice were intraperitoneally injected with DAP immediately after PPE infusion. The maximum diameter of the abdominal aorta was measured by ultrasound system, and aortic mural changes were investigated by Elastica van Gieson (EVG) staining and immunohistochemical staining. The results demonstrated that DAP significantly suppressed PPE-induced AAA formation and attenuated the depletion of aortic medial elastin and smooth muscle cells in the media of the aorta. Furthermore, the density of mural macrophages, T cells and B cells were significantly attenuated in DAP-treated AAA mice. In addition, treatment with DAP resulted in a significant reduction in mural neovessels. These findings indicated that DAP may limit the formation and progression of experimental aneurysms by inhibiting mural inflammation and angiogenesis. These data confirmed the translational potential of DAP inclinical AAA inhibition strategies.

Aortic Aneurysm Natural Progression is Not Influenced by Concomitant Malignancy and Chemotherapy

BACKGROUND

Aortic aneurysms occur concomitantly with malignancy in approximately 1.0-17.0% of patients. There is little published information regarding the effects of subsequent oncological therapies on aortic aneurysm growth. The aim of this study was to determine the effects of chemoradiation therapies on the natural progression of small abdominal aortic aneurysm (AAA), thoracic aortic aneurysm, and thoracoabdominal aortic aneurysm.

METHODS

Patients with aortic aneurysms with and without malignancy between 2005 and 2017 were identified within institutional databases using Current Procedural Terminology and International Classification of Disease codes. Inclusion criteria included complete chemotherapy documentation, a minimum of 3 multiplanar axial/coronal imaging or ultrasonography before, during, and after receiving therapy or 2 studies for patients without malignancy. Propensity matching, Cox and linear regression, and Kaplan-Meier survival analyses were performed.

RESULTS

A total of 159 (172 aneurysms) patients with malignancy and 127 (149 aneurysms) patients without malignancy were included. Average patient demographics were 74.4 ± 9.8-years-old, Caucasian (66.8%), male (70.3%), with hypertension (71.1%), current smoking (24.5%), coronary atherosclerotic disease (26.2%), and AAA (71.0%). The most common malignancy was lung cancer (48.4%) with most chemotherapy regimens including a platinum-based alkylating agent and concurrent antimetabolite (56.0%). The overall median follow-up time was 28.2 (range 3.1-174.4) months. Aortic aneurysms in patients without malignancy grew to larger sizes (4.43 ± 0.96 vs. 4.14 ± 1.00, P = 0.008) with similar median growth rates (0.12 vs. 0.12 cm/year, P = 0.090), had more atypical morphologic features (14.1% vs. 0.6%, P < 0.001), more frequently underwent repair (22.1% vs. 8.7%, P = 0.001), and more frequently required emergency repair for rupture (5.4% vs. 0.0%, P = 0.087). Cox regression identified initial aortic size ≥4.0 cm (hazard ratio [HR] 3.028), AAA (HR 2.146), chronic aortic findings (3.589), and the use of topoisomerase inhibitors (HR 2.694). Linear regression demonstrated increased growth rates predicted by antimetabolite chemotherapy (β 0.170), initial aortic size (β 0.086), and abdominal aortic location (β 0.139, all P < 0.002).

CONCLUSIONS

Small aortic aneurysms with concomitant malignancies are discovered at smaller initial sizes, grow at similar rates, require fewer interventions, and have fewer ruptures and acute dissections than patients without malignancy. Antimetabolite therapies modestly accelerate aneurysmal growth, and patients receiving topoisomerase inhibitors may require earlier repair. Patients with concomitant disease can be confidently treated according to standard institutional aneurysm surveillance protocols. Overall, we recommend treatment of the malignancy before small aortic aneurysm repair as these aneurysms behave similarly to those in patients without malignancy.

Quercetin Downregulates Cyclooxygenase-2 Expression and HIF-1α/VEGF Signaling-Related Angiogenesis in a Mouse Model of Abdominal Aortic Aneurysm

Objective

Abdominal aortic aneurysm (AAA) development has been characterized by increased expression of vascular endothelial growth factor (VEGF), which contributes to angiogenesis via cyclooxygenase-2 (COX-2). Quercetin, one of the most common and well-researched flavonoids and abundant in vegetables and fruits, has beneficial effects in inhibiting angiogenesis. This study investigated the antiangiogenic effects of quercetin on experimental aneurysms.

Methods

We utilized the in vivo AAA mouse model induced by the periaortic application of CaCl₂ to examine the effectiveness of quercetin in blocking angiogenesis. Quercetin was administered at 60 mg/kg once daily on the day of the AAA induction and then continued for 6 weeks. Celecoxib, a selective COX-2 inhibitor, was used as the positive control.

Results

Our results demonstrated that quercetin significantly attenuated aneurysm growth in AAA mice and medial neovascularization. Accordingly, quercetin decreased the expression of proangiogenic mediators, including VEGF-A, intercellular adhesion molecule-1, vascular cell adhesion molecule 1, and vascular endothelial cadherin. Quercetin treatment also inhibited the expression of COX-2 and hypoxia-inducible factor 1α (HIF-1α). It was also found that quercetin-3-glucuronide, a major quercetin metabolite, downregulated the expression of COX-2, HIF-1α, VEGF-A, and matrix metalloproteinase activities in aortic vascular smooth muscle cells isolated from AAA mice.

Conclusion

Quercetin attenuates neovascularization during AAA growth, and this effect is mediated via the inhibition of COX-2, which decreases HIF-1α/VEGF signaling-related angiogenesis.

Experimental abdominal aortic aneurysm growth is inhibited by blocking the JAK2/STAT3 pathway

BACKGROUND

The JAK/STAT pathway is a vital transcription signaling pathway that regulates gene expression and cellular activity. Our recently published study highlighted the role of IL-17A in abdominal aortic aneurysm (AAA) formation and rupture. IL-17A has been proven to upregulate vascular endothelial growth factor (VEGF) expression in some diseases. However, no study has demonstrated the relationships among JAK2/STAT3, IL-17A and VEGF. Therefore, we hypothesized that IL-17A may up-regulate VEGF expression via the JAK2/STAT3 signaling pathway to amplify the inflammatory response, exacerbate neovascularization, and accelerate AAA progression.

METHODS

To fully verify our hypothesis, two separate studies were performed: i) a study investigating the influence of JAK2/STAT3 on AAA formation and progression. ii) a study evaluating the relationship among IL-17A, JAK2/STAT3 and VEGF. Human tissues were collected from 7 AAA patients who underwent open surgery and 7 liver transplantation donors. All human aortic tissues were examined by histological and immunohistochemical staining, and Western blotting. Furthermore, mouse aortic tissues were also examined by histological and immunohistochemical staining and Western blotting, and the mouse aortic diameters were assessed by high-resolution Vevo 2100 microimaging system.

RESULTS

Among human aortic tissues, JAK2/STAT3, IL-17A and VEGF expression levels were higher in AAA tissues than in control tissues. Group treated with WP1066 (a selective JAK2/STAT3 pathway inhibitor), IL-17A, and VEGF groups had AAA incidences of 25%, 40%, and 65%, respectively, while the control group had an incidence of 75%. Histopathological analysis revealed that the IL-17A- and VEGF-related inflammatory responses were attenuated by WP1066. Thus, blocking the JAK2/STAT3 pathway with WP1066 attenuated experimental AAA progression. In addition, in study ii, we found that IL-17A siRNA seemed to attenuate the expression of IL-17A and VEGF in vivo study; treatment with VEGF siRNA decreased the expression of VEGF, while IL-17A expression remained high. In an in vitro study, rhIL-17A treatment increased JAK2/STAT3 and VEGF expression in macrophages in a dose-dependent manner.

CONCLUSION

Blocking the JAK2/STAT3 pathway with WP1066 (a JAK2/STAT3 specific inhibitor) attenuates experimental AAA progression. During AAA progression, IL-17A may influence the expression of VEGF via the JAK2/STAT3 signaling pathway. This potential mechanism may suggest a novel strategy for nonsurgical AAA treatment.

Kallistatin correlates with inflammation in abdominal aortic aneurysm and suppresses its formation in mice

Background

Kallistatin (KS), encoded by SERPINA4, was suggested to play a protective role in many cardiovascular diseases. However, its role in the pathogenesis of abdominal aortic aneurysm (AAA) remains unclear. The aim of this study was to examine the potential association of KS with AAA pathogenesis.

Methods

We examined KS (SERPINA4) expression in human AAA by PCR, immunohistochemistry, western blotting, and enzyme-linked immunosorbent assay (ELISA) and analyzed correlations between kallistain and clinical data. We then analyzed the effect of recombinant KS on AAA formation and the Wingless (Wnt) signaling pathway in a mouse AAA model developed by angiotensin II (AngII) infusion to apolipoprotein E-deficient (ApoE^-/-) mice.

Results

In AAA tissue samples, KS was significantly increased compared with samples from the control group (P<0.001, P<0.001, respectively). Clinically, decreased SERPINA4 expression in AAA tissue samples represented an increased rate of iliac artery aneurysm [odds ratio (OR): 0.017; P=0.040]. And decreased plasma KS level represented a high risk for rupture (OR: 0.837; P=0.034). KS inhibited AAA formation and blocked the Wnt signaling pathway in AngII-infused ApoE^-/- mice.

Conclusions

The present study demonstrates that aberrant changes in KS expression occur in AAA. KS plays an important anti-inflammatory role and showed important clinical correlations in AAA. Decreased KS (SERPINA4) level is a risk factor of AAA rupture. Our pre-clinical animal experiments indicate that treatment with recombination KS suppresses AngII-induced aortic aneurysm formation and might be a new target for the drug therapy of AAA.

Genetic and epigenetic regulation of abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are focal dilations of the aorta that develop from degenerative changes in the media and adventitia of the vessel. Ruptured AAAs have a mortality of up to 85%, thus it is important to identify patients with AAA at increased risk for rupture who would benefit from increased surveillance and/or surgical repair. Although the exact genetic and epigenetic mechanisms regulating AAA formation are not completely understood, Mendelian cases of AAA, which result from pathologic variants in a single gene, have helped provide a basic understanding of AAA pathophysiology. More recently, genome wide associated studies (GWAS) have identified additional variants, termed single nucleotide polymorphisms, in humans that may be associated with AAAs. While some variants may be associated with AAAs and play causal roles in aneurysm pathogenesis, it should be emphasized that the majority of SNPs do not actually cause disease. In addition to GWAS, other studies have uncovered epigenetic causes of disease that regulate expression of genes known to be important in AAA pathogenesis. This review describes many of these genetic and epigenetic contributors of AAAs, which altogether provide a deeper insight into AAA pathogenesis.

Ulinastatin Inhibits the Formation and Progression of Experimental Abdominal Aortic Aneurysms

AIMS

Aortic mural inflammatory damage takes a vital part in abdominal aortic aneurysm (AAA). Recently, ulinastatin (UTI) has attracted attention for its anti-inflammatory function. Our study aimed to evaluate potential influences of UTI on experimental AAA.

METHODS

A mouse model of AAA was induced by infusion of porcine pancreatic elastase (PPE) into the abdominal aorta. Mice were treated with UTI (50,000 U/kg/day i.p.) beginning either immediately or on the 4th day after PPE infusion, with treatment being continued until the 14th day. UTI effects were assessed by aortic diameter measurements and aortic histopathological analysis.

RESULTS

Significant and time-dependent aortic diameter enlargement persisted in the control mice from day 0. In the UTI group, aortic diameter increased, and depletion of aortic mural smooth muscle cells and elastin was significantly -attenuated. Simultaneously, mural CD68+ macrophages, CD8+ T-cell and B220+ B-cell density, as well as neoangiogenesis were suppressed by UTI. In addition, delayed UTI treatment could still effectively limit aneurysm expansion.

CONCLUSIONS

UTI treatment limits the formation and growth of experimental AAA, and UTI may be a potential treatment for early AAA disease.

Genome-Wide Expression Profiling Unveils Autoimmune Response Signatures in the Perivascular Adipose Tissue of Abdominal Aortic Aneurysm

Objective- Perivascular adipose tissue (PVAT) is thought to play a role in vascular homeostasis and in the pathogenesis of large vessel diseases, including abdominal aortic aneurysm (AAA). Herein, we tested the hypothesis that locally restricted transcriptional profiles characterize PVAT surrounding AAA, indicating specific dysfunctions associated with the disease. Approach and Results- Using a paired sample design to limit the effects of interindividual variation, we performed a microarray-based investigation of the PVAT transcriptome in 30 patients with AAA, comparing the adipose layer of the dilated abdominal aorta with that of the not-dilated aortic neck in each patient. Furthermore, we used a state-of-the-art data mining procedure to remove the effect of confounders produced by high-throughput gene expression techniques. We found substantial differences in PVAT gene expression clearly distinguishing the dilated from the not-dilated aorta, which increased in number and magnitude with increasing AAA diameter. Comparisons with other adipose depots (omental or subcutaneous fat) confirmed that gene expression changes are locally restricted. We dissected putative mechanisms associated with AAA PVAT dysfunction through a functional enrichment network analysis: both innate and adaptive immune-response genes along with genes related to cell-death pathways, metabolic processes of collagen, sphingolipids, aminoglycans, and extracellular matrix degradation were strongly overrepresented in PVAT of AAA compared with PVAT of the not-dilated aorta. Conclusions- Our results support a possible function of PVAT in AAA pathogenesis and suggest that AAA is an immunologic disease with an underlying autoimmune component. Interfering with these disease-specific pathways would clarify their precise role in AAA pathogenesis.

Inflammation promotes progression of thrombi in intracranial thrombotic aneurysms

Advances in the understanding of the pathogenesis of arteriosclerosis, abdominal aorta aneurysms and dissections, and carotid artery plaques have focused on chronic inflammation. In this study, we report that inflammatory changes of thrombi contribute to the enlargement and growth of giant intracranial thrombotic aneurysms. Surgical and postmortem samples were collected from 12 cases of large or giant intracranial thrombotic aneurysms diagnosed via pathological investigations. Degeneration of the aneurysmal wall and the infiltration of inflammatory cells in the thrombi were assessed. The number of blood cells and immunohistochemical stain-positive cells was enumerated, and the inflammation and neovascularization in the thrombi were assessed. In all cases, the appearance of inflammatory cells (CD68⁺ cells, CD206⁺ cells, lymphocytes, and neutrophils) was apparent in the thrombi. The number of CD34⁺ cells was moderately correlated with the number of CD68⁺ cells, and CD34⁺ cells significantly and strongly correlated with the number of CD206⁺ cells. Based on the number of neutrophils per CD68⁺ cells, we classified the cases into 2 groups: a macrophage inflammation-dominant group and a neutrophilic inflammation-dominant group. The neutrophilic inflammation-dominant group had significantly more cases with previous treatments and neurological symptoms due to mass effect than the macrophage inflammation-dominant group. Chronic inflammation due to macrophages in thrombi is a fundamental mechanism in the enlargement of an intracranial thrombotic aneurysm, and neutrophilic inflammation can accelerate this process. Microvascularization in thrombi is linked to inflammation and might promote thickening of the intima and repeated intimal microbleeds.

Inhibition of VEGF (Vascular Endothelial Growth Factor)-A or its Receptor Activity Suppresses Experimental Aneurysm Progression in the Aortic Elastase Infusion Model

OBJECTIVE

We examined the pathogenic significance of VEGF (vascular endothelial growth factor)-A in experimental abdominal aortic aneurysms (AAAs) and the translational value of pharmacological VEGF-A or its receptor inhibition in aneurysm suppression. Approaches and Results: AAAs were created in male C57BL/6J mice via intra-aortic elastase infusion. Soluble VEGFR (VEGF receptor)-2 extracellular ligand-binding domain (delivered in Ad [adenovirus]-VEGFR-2), anti-VEGF-A mAb (monoclonal antibody), and sunitinib were used to sequester VEGF-A, neutralize VEGF-A, and inhibit receptor tyrosine kinase activity, respectively. Influences on AAAs were assessed using ultrasonography and histopathology. In vitro transwell migration and quantitative reverse transcription polymerase chain reaction assays were used to assess myeloid cell chemotaxis and mRNA expression, respectively. Abundant VEGF-A mRNA and VEGF-A-positive cells were present in aneurysmal aortae. Sequestration of VEGF-A by Ad-VEGFR-2 prevented AAA formation, with attenuation of medial elastolysis and smooth muscle depletion, mural angiogenesis and monocyte/macrophage infiltration. Treatment with anti-VEGF-A mAb prevented AAA formation without affecting further progression of established AAAs. Sunitinib therapy substantially mitigated both AAA formation and further progression of established AAAs, attenuated aneurysmal aortic MMP2 (matrix metalloproteinase) and MMP9 protein expression, inhibited inflammatory monocyte and neutrophil chemotaxis to VEGF-A, and reduced MMP2, MMP9, and VEGF-A mRNA expression in macrophages and smooth muscle cells in vitro. Additionally, sunitinib treatment reduced circulating monocytes in aneurysmal mice.

CONCLUSIONS

VEGF-A and its receptors contribute to experimental AAA formation by suppressing mural angiogenesis, MMP and VEGF-A production, myeloid cell chemotaxis, and circulating monocytes. Pharmacological inhibition of receptor tyrosine kinases by sunitinib or related compounds may provide novel opportunities for clinical aneurysm suppression.

Is Abdominal Aortic Aneurysm Behavior after Endovascular Repair Associated with Aneurysm Wall Density on Computed Tomography Angiography?

Background and objectives: Abdominal aortic aneurysm (AAA) growth is unpredictable after the endovascular aneurysm repair (EVAR). Continuing aortic wall degradation and weakening due to hypoxia may have a role in post-EVAR aneurysm sac growth. We aimed to assess the association of aortic wall density on computed tomography angiography (CTA) with aneurysm growth following EVAR. Materials and Methods: A total of 78 patients were included in the study. The control group consisted of 39 randomly assigned patients without aortic pathology. Post-EVAR aneurysm sac volumes on CTA were measured twice during the follow-up period to estimate aneurysm sac behavior. A maximum AAA sac diameter, aortic wall and lumen densities in Hounsfield units (HU) on CTA were measured. A relative aortic wall density (the ratio of aortic wall to lumen densities) was calculated. A statistical data analysis was performed using standard methods. Results: An increase in the AAA sac volume was observed in 12 (30.8%) cases. Median relative aortic wall density on CTA scores in both the patient and the control group at the level of the diaphragm were similar: 0.15 (interquartile range (IQR), 0.11–0.18) and 0.16 (IQR 0.11–0.18), p = 0.5378, respectively. The median (IQR) relative aortic wall density score at the level of the maximum AAA diameter in the patient group was lower than at the level below renal arteries in the control group: 0.10 (0.07–0.12) and 0.17 (0.12–0.23), p < 0.0001, respectively. The median (IQR) relative growing AAA sac wall density score was lower than a relative stable/shrinking AAA sac wall density score: 0.09 (0.06–0.10) and 0.11 (0.09–0.13), p = 0.0096, respectively. Conclusions: A lower aortic aneurysm wall density on CTA may be associated with AAA growth after EVAR.

Circular RNA microarray expression profile in 3,4-benzopyrene/angiotensin II-induced abdominal aortic aneurysm in mice

Abdominal aortic aneurysm (AAA) is an unpredictable but lethal disease that poses a therapeutic dilemma. Circular RNAs (circRNAs), whose functional roles as transcriptional regulators and microRNA (miRNA) sponges have been shown in former studies, are potential biomarkers for many diseases. AAA in male C57BL/6 J mice was induced by coadministration of angiotensin II (Ang II) and 3,4-benzopyrene (BaP). The circRNA expression profiling was performed using two samples from the control group and two samples from the AAA group. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to confirm the reliability of the microarray results. Among the 14 236 detected circRNAs, 413 showed obvious expression changes (fold change ≥ 2; P < 0.05) between the BaP/Ang II-induced AAA group and control group. Of the 413 that showed significant changes, 271 were upregulated, while the other 142 were downregulated. The expression levels of 10 circRNAs were validated by qRT-PCR. The interactions of the differentially expressed circRNAs with miRNAs were predicted. Immunofluorescence showed prominent vascular smooth muscle cell apoptosis in abdominal aortic tissues in the BaP/Ang II group. Furthermore, a circRNA-miRNA coexpression network based on six apoptosis-related circRNAs was built. The genes regulated by the network mapped to several pathways, including apoptosis, the IL-17 signaling pathway, and vascular endothelial growth factor signaling pathway, all of which are related to AAA formation. This study performed circRNA expression profiling in AAA and the results specifically predicted the regulatory role of circRNAs in AAA pathogenesis.

Pseudoaneurysm presenting around polytetrafluoroethylene fiber following microvascular decompression: A case report and literature review

We report the first case of pseudoaneurysm associated with polytetrafluoroethylene fiber used in microvascular decompression (MVD). A 62-year-old female who had undergone MVD for hemifacial spasm 30 years ago presented with a 4-month history of progressive facial palsy. Computed tomography angiography revealed a large thrombosed aneurysm originating from the right posterior inferior cerebellar artery and having a mass effect upon the pons. The aneurysm was treated by trapping and bypass procedure. Intraoperatively, the pseudoaneurysm adhered to the dura mater, and the thrombus contained a large amount of polytetrafluoroethylene fiber. The cause and management of pseudoaneurysm after MVD is discussed.

Molecular determinants of microvascular dysfunction in hypertensive pregnancy and preeclampsia

Preeclampsia is a pregnancy-related disorder characterized by hypertension and often fetal intrauterine growth restriction, but the underlying mechanisms are unclear. Defective placentation and apoptosis of invasive cytotrophoblasts cause inadequate remodeling of spiral arteries, placental ischemia, and reduced uterine perfusion pressure (RUPP). RUPP causes imbalance between the anti-angiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin and the pro-angiogenic vascular endothelial growth factor and placental growth factor, and stimulates the release of proinflammatory cytokines, hypoxia-inducible factor, reactive oxygen species, and angiotensin AT1 receptor agonistic autoantibodies. These circulating factors target the vascular endothelium, smooth muscle and various components of the extracellular matrix. Generalized endotheliosis in systemic, renal, cerebral, and hepatic vessels causes decreases in endothelium-derived vasodilators such as nitric oxide, prostacyclin and hyperpolarization factor, and increases in vasoconstrictors such as endothelin-1 and thromboxane A2. Enhanced mechanisms of vascular smooth muscle contraction, such as intracellular Ca2+ , protein kinase C, and Rho-kinase cause further increases in vasoconstriction. Changes in matrix metalloproteinases and extracellular matrix cause inadequate vascular remodeling and increased arterial stiffening, leading to further increases in vascular resistance and hypertension. Therapeutic options are currently limited, but understanding the molecular determinants of microvascular dysfunction could help in the design of new approaches for the prediction and management of preeclampsia.

Cerebral Aneurysms Differ in Patients with Hysterectomies

OBJECTIVE

Female sex is a well-known risk factor for aneurysm formation. Although the role of the ovaries and estrogen in aneurysm development has been supported, other organ-hormone pairs unique between sexes also may be implicated. In this study, we aimed to determine whether intracranial aneurysms microsurgically clipped in patients with previous hysterectomies exhibit any unique aneurysm characteristics from those without hysterectomies.

METHODS

Solitary aneurysms microsurgically treated by the senior author (M.T.L.) were included from a database of patients treated between January 2010 and April 2013 at a tertiary academic medical center. Only female patients and patients equal or older in age to the youngest patient in the hysterectomy group were included in the control group. Patient and aneurysm characteristics were compared using the χ² test for categorical variables and the independent t test analysis for continuous variables.

RESULTS

A total 233 patients were included in the study. Forty-three patients (19%) had undergone a previous hysterectomy; none had oophorectomies recorded. No difference in mean age (P = 0.89), hypertension (P = 0.38), alcohol use (P = 0.87), tobacco use (P = 0.22), or aneurysm location (P = 1) existed. However, patients in the hysterectomy group more often presented in a good neurologic condition before surgery (88% vs. 74%, P = 0.04) and had fewer large aneurysms (8% vs. 24%, P = 0.03). Also, fewer presented with a ruptured aneurysm (28%) then the nonhysterectomy group (51%) (P = 0.004).

CONCLUSIONS

Female patients with a surgical history of a hysterectomy have a lower rate of large aneurysms, present in better neurologic condition, and are less likely to present with a ruptured aneurysm than females without a hysterectomy.

Inflammatory Mechanisms of Cardiovascular Remodeling

Inflammation and fibrosis play an important role in the development and progression of cardiovascular diseases. Acute coronary syndrome (ACS) is caused by rupture of inflamed atherosclerotic plaque and subsequent atherothrombosis. Recent studies have shown that inflammatory markers such as C-reactive protein (CRP) can predict ACS development and have demonstrated the effectiveness of new therapeutic approaches targeting inflammation. Studies have also shown that an enhanced inflammatory response after myocardial infarction (MI) is associated with cardiac rupture, ventricular aneurysm formation, and exacerbation of left ventricular (LV) remodeling. Inflammation is a physiological reaction in which fibrosis is induced to facilitate the healing of tissue damage. However, when an excessive inflammatory response consisting mainly of monocytes/macrophages is induced by various factors, impaired reparative fibrosis and resulting pathological remodeling processes may occur. A similar phenomenon is observed in abdominal aortic aneurysm (AAA) expansion. In contrast, myocardial diseases such as inflammatory dilated cardiomyopathy (DCMI) and valvular diseases such as aortic valve stenosis (AS) are characterized by chronic inflammation mediated mainly by T lymphocytes and the associated enhancement of reactive fibrosis. Thus, inflammation can take 2 paths (the inhibition or promotion of fibrosis), depending on the phase of inflammation, inducing pathological cardiovascular remodeling. Elucidation of the regulatory mechanisms of inflammation and fibrosis will contribute to the development of new therapeutic approaches for cardiovascular diseases.

miR-195 suppresses abdominal aortic aneurysm through the TNF-α/NF-κB and VEGF/PI3K/Akt pathway

In the present study, the function of microRNA (miR)‑195 on abdominal aortic aneurysm (AAA) and its possible mechanism were investigated. Reverse transcription‑quantitative polymerase chain reaction analysis was used to detect the expression of miR‑195 in patients with AAA. The expression levels of miR‑195 in patients with AAA were effectively increased. The present study also used miR‑195 mimics to increase the expression of miR‑195, and ELISA kits and western blot analysis were used to analyze the levels of interleukin (IL)‑1β and IL‑6, and the protein expression levels of matrix metalloproteinase (MMP)‑2, MMP‑9, tumor necrosis factor (TNF)‑α, nuclear factor (NF)‑κB, vascular endothelial growth factor (VEGF), phosphoinositide 3‑kinase (PI3K) and phosphorylated (p‑)Akt. The overexpression of miR‑195 promoted the levels of IL‑1β and IL‑6, induced the protein expression of MMP‑2 and MMP‑9, upregulated the protein expression of TNF‑α and NF‑κB, and suppressed the protein expression levels of VEGF, PI3K and p‑Akt in angiotensin II‑vascular smooth muscle cells. In addition, TNF‑α promoted the pre‑inflammatory effect of miR‑195 on the protein expression levels of TNF‑α and NF‑κB, levels of IL‑1β and IL‑6, and protein expression levels of MMP‑2 and MMP‑9 in the angiotensin II‑vascular smooth muscle cells. Suppression of PI3K promoted the pre‑inflammatory effect of miR‑195 on the protein expression of PI3K, p‑Akt and VEGF, the levels of IL‑1β and IL‑6, and the protein expression of MMP‑2 and MMP‑9 in angiotensin II‑vascular smooth muscle cells. Combined, these results suggested that miR‑195 suppressed AAA inflammation through the TNF‑α/NF‑κB and VEGF/PI3K/Akt pathways.

Cytokine Profile of Human Abdominal Aortic Aneurysm: Involvement of JAK/STAT Pathway

Objective: Abdominal aortic aneurysm (AAA) is characterized by inflammation and destruction of normal tissue architecture. The present study aimed to evaluate the inflammatory signaling cascade by analyzing the cytokines of AAA tissue.

Materials and Methods: We analyzed the comprehensive cytokine secretion profiles of 52 cytokines from human AAA in four patients with AAA using fluorescent beads-based multiplex assay. Further, the effect of janus kinase (JAK) inhibition by pyridone 6 on cytokine profiles was also evaluated.

Results: Cytokine secretion profiles were found to be similar among the four patients. A high level of JAK/signal transducers and activator of transcription (STAT) pathway activity in AAA tissue in culture was maintained, which may be attributed to the secretion of endogenous JAK-activating cytokines. Inhibition of JAK by pyridone 6 resulted in the suppression of STAT3 phosphorylation and secretion of a subset of chemokines and JAK-activating cytokines. However, the inhibition of JAK had no effect on the secretion of matrix metalloproteinase (MMP)-2, MMP-9, or TGF-β family that is responsible for the metabolism of extracellular matrix.

Conclusion: The findings of the present study suggested that AAA tissue exhibits a stereotypical profile of cytokine secretion, where JAK/STAT pathway may play a role in regulating a subset of cytokines. Identification of such a cytokine profile may reveal potential diagnostic markers and therapeutic targets for AAA.

Effect of AMPK signal pathway on pathogenesis of abdominal aortic aneurysms

Background and aims

Determine the effect of AMPK activation and inhibition on the development of AAA (abdominal aortic aneurysm).

Methods

AAA was induced in ApoE^−/− mice by Ang II (Angiotensin II)-infusion. AICAR (5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside) was used as AMPK activator and Compound C was used as AMPK inhibitor. We further investigate the effect of metformin, a widely used anti-diabetic drug which could activate AMPK signal pathway, on the pathogenesis of aneurysm.

Results

Phospho-AMPK level was significantly decreased in AAA tissue compared with control aortas. AICAR significantly reduced the incidence, severity and mortality of aneurysm in the Ang II-infusion model. AICAR also alleviated macrophage infiltration and neovascularity in Ang II infusion model at day 28. The expression of pro-inflammatory factors, angiogenic factors and the activity of MMPs were also alleviated by AICAR during AAA induction. On the other hand, Compound C treatment did not exert obvious protective effect. AMPK activation may inhibit the activation of nuclear factor-κB (NF-κB) and signal transducer and activator of transcription-3 (STAT-3) during AAA induction. Administration of metformin also activated AMPK signal pathway and retarded AAA progression in Ang II infusion model.

Conclusions

Activation of AMPK signaling pathway may inhibit the Ang II-induced AAA in mice. Metformin may be a promising approach to the treatment of AAA.