Background Thoracic aortic aneurysms (TAAs) develop through an asymptomatic process resulting in gross dilatation that progresses to rupture if left undetected and untreated. If detected, TAA patients are followed over time until the risk of rupture outweighs the risk of surgical repair. Current methodologies for tracking TAA size are limited to expensive computed tomography or magnetic resonance imaging, as no acceptable population screening tools are currently available. Previous studies from this laboratory and others have identified differential protein profiles for the matrix metalloproteinases (MMPs) and their endogenous tissue inhibitors (TIMPs), in ascending TAA tissue from patients with bicuspid aortic valves (BAV), versus patients with idiopathic degenerative disease and a tricuspid aortic valve (TAV). Additionally, altered microRNA (miR) expression levels have also been reported in TAAs as compared to normal aortic tissue. The objective of the present study was to identify circulating factors within the plasma that could serve as potential biomarkers for distinguishing etiological subtypes of aneurysm disease. Methods Ascending TAA tissue and plasma specimens were obtained from BAV (n=21) and TAV (n=21) patients at the time of surgical resection. The protein abundance of key MMPs (-1, -2, -3, -8, -9) and TIMPs (-1, -2, -3, -4), and microRNAs (-1, -21, -29a, -133a, -143, -145) was examined using a multi-analyte protein profiling system or by quantitative PCR, respectively. Results were compared to normal aortic tissue and plasma obtained from patients without aortic disease (n=10). Results Significant (p < 0.05) differences in standardized miR-1 and miR-21 abundance between BAV and TAV aortic tissue samples and different tissue and plasma profiles of analyte differences from normal aorta where observed between the BAV and TAV groups. Linear regression analysis significant linear relationships in plasma and tissue measurements only for MMP-8 and TIMPs -1, -3 and -4 (p < 0.05). Receiver operator curve analysis revealed specific cassettes of analytes predictive of TAA disease. Relative to normal aorta, BAV proteolytic balance was significantly increased for MMP-1, -2 and -7, and for decreased MMP-8 and -9. In contrast, TAV proteolytic balance relative to normal aorta was significantly increased only for MMP-1 and decreased for MMP-8 and -9. Conclusions Taken together these unique data demonstrate differential plasma profiles of MMPs, TIMPs, and miRs in ascending TAA specimens from patients with BAV and TAV. These results suggest that circulating biomarkers may form the foundation for a broader platform of biomarkers capable of detecting the presence of TAA using a simple blood test and may also be useful in personalized medicine strategies to distinguish between etiological subtypes of TAAs in patients with aneurysm disease.

IMPORTANCE Although fluoroquinolones are commonly prescribed antibiotics in the US, recent international studies have shown an increased risk of aortic aneurysm and dissection after fluoroquinolone use, leading to US Food and Drug Administration warnings limiting use for high-risk patients. It is unclear whether these data are true for the US population and who is truly high risk. OBJECTIVE To assess aortic aneurysm and dissection risks in a heterogeneous US population after fluoroquinolone use. DESIGN, SETTING, AND PARTICIPANTS Prescription fills for fluoroquinolones or a comparator antibiotic from 2005 to 2017 among commercially insured individuals aged 18 to 64 years were identified in this retrospective analysis of MarketScan health insurance claims. This cohort study included 27 827 254 US adults (47 596 545 antibiotic episodes), aged 18 to 64 years, with no known previous aortic aneurysm or dissection, no recent antibiotic exposure, and no recent hospitalization. EXPOSURES Outpatient fill of an oral fluoroquinolone or comparator antibiotic (amoxicillin-clavulanate, azithromycin, cephalexin, clindamycin, and sulfamethoxazoletrimethoprim). MAIN OUTCOMES AND MEASURESThe 90-day incidence of aortic aneurysm and dissection. Inverse probability of treatment weighting in Cox regression was used to estimate the association between fluoroquinolone fill and 90-day aneurysm incidence. Interaction terms were used to assess the association of known risk factors (ie, sex, age, and comorbidities) with aneurysm after fluoroquinolone use. Data analysis was performed March 2019 to May 2020. RESULTSOf 47 596 545 prescription fills, 9 053 961 (19%) were fluoroquinolones and 38 542 584 (81%) were comparator antibiotics. The median (interquartile range) age of adults with fluoroquinolone fills was 47 (36-57) years vs 43 (31-54) years with comparator antibiotic fills. Women comprised 61.3% of fluoroquinolone fills and 59.5% of comparator antibiotic fills. Before weighting, the 90-day incidence of newly diagnosed aneurysm was 7.5 cases per 10 000 fills (6752 of 9 053 961) after fluoroquinolones compared with 4.6 cases per 10 000 fills (17 627 of 38 542 584) after comparator antibiotics. After weighting for demographic characteristics and comorbidities, fluoroquinolone fills were associated with increased incidence of aneurysm formation (hazard ratio [HR], 1.20; 95% CI, 1.17-1.24). More specifically, compared with comparator antibiotics, fluoroquinolone fills were associated with increased 90-day incidence of abdominal aortic aneurysm (

Background Hypertension (HTN) has long been associated with abdominal aortic aneurysm (AAA) development, and these cardiovascular pathologies are biochemically characterized by elevated plasma levels of angiotensin II (AngII) as well as interleukin-6 (IL-6). A biologic relationship between HTN and AAA has not been established, however. Accordingly, the objective of this study was to evaluate whether elevated tension may initiate IL-6 production to accumulate monocyte/macrophages and promote dilation of the abdominal aorta (AA). Methods An IL-6 infusion model (4.36 µg/kg/day) was created utilizing an osmotic infusion pump, and after 4 weeks, AA diameter was measured by digital microscopy. The AA was then excised for CD68 immunostaining and flow cytometric analysis with CD11b and F4/80 to identify macrophages. Aortic segments from wild-type mice were suspended on parallel wires in an ex vivo tissue myograph at experimentally derived optimal tension (1.2 g) and in the presence of elevated tension (ET, 1.7 g) for 3 hr, and expression of IL-6 and monocyte chemoattractant protein-1 (MCP-1) was evaluated by quantitative polymerase chain reaction (QPCR). Isolated aortic vascular smooth muscle cells (VSMCs) were subjected to 12% biaxial cyclic stretch or held static (control) for 3 hr (n = 7), and IL-6 and MCP-1 expressions were evaluated by QPCR. Results Four-week IL-6 infusion resulted in an AA outer diameter that was 72.5 ± 5.6% (P < 0.05) greater than that of control mice, and aortic dilation was accompanied by an accumulation of macrophages in the AA medial layer as defined by an increase in CD68 + staining as well as an increase by flow cytometric quantification of CD11b+/F4/80+ cells. Wild-type AA segments did not respond to ex vivo application of ET but cyclic stretch of isolated VSMCs increased IL-6 (2.03 ± 0.3 fold) and MCP-1 (1.51 ± 0.11 fold) expression compared to static control (P < 0.05). Pretreatment with the selective STAT3 inhibitor WP1066 blunted the response in both cases. Interestingly, AngII did not stimulate expression of IL-6 and MCP-1 above that initiated by tension and again, the response was inhibited by WP1066, supporting an integral role of STAT3 in this pathway. Conclusions An IL-6 infusion model can initiate macrophage accumulation as well as aortic dilation, and under conditions of elevated tension, this proinflammatory cytokine can be produced by aortic VSMCs. By activation of STAT3, MCP-1 is expressed to increase media macrophage abundance and create an environment susceptible to dilation. This biomechanical association between HTN and aortic dilation may allow for the identification of novel therapeutic strategies.

Background MicroRNAs (miRNAs) and histone deacetylases (HDACs) serve a significant role in the pathogenesis of a variety of cardiovascular diseases. The transcriptional regulation of miRNAs is poorly understood in cardiac hypertrophy. We investigated whether the expression of miR-133a is epigenetically regulated by Class I and IIb HDACs during hypertrophic remodeling. Methods and Results Transverse aortic constriction (TAC) was performed in CD1 mice to induce pressure overload (PO) hypertrophy. Mice were treated with Class I and IIb HDAC inhibitor via drinking water for 2 and 4 weeks post-TAC. miRNA expression was determined by real time PCR. Echocardiography was performed at baseline and post-TAC endpoints for structural and functional assessment. Chromatin immunoprecipitation (ChIP) was used to identify HDACs and transcription factors associated with miR-133a promoter. miR-133a expression was downregulated by 0.7 and 0.5 fold at 2 weeks and 4 weeks post-TAC respectively as compared to vehicle-control (P < 0.05). HDAC inhibition prevented this significant decrease 2 weeks post-TAC and maintained miR-133a expression near vehicle-control levels, which coincided with 1) a decrease in connective tissue growth factor (CTGF) expression, 2) a reduction in cardiac fibrosis and left atrium diameter (marker of end-diastolic pressure) suggesting an improvement in diastolic function. ChIP analysis revealed that HDAC1 and HDAC2 are present on the miR-133a enhancer regions. Conclusions The results reveal that HDACs play a role in the regulation of PO-induced miR-133a downregulation. This work is the first to provide insight into an epigenetic-miRNA regulatory pathway in PO-induced cardiac fibrosis.

Objective Membrane type-1 MMP (MT1-MMP) is elevated during thoracic aortic aneurysm (TAA) development in mouse models, and plays an important role in the activation of MMP-2 and the release of matrix bound TGF-β. This study tested the hypothesis that MT1-MMP is subject to protein kinase C (PKC)-mediated regulation, which alters intracellular trafficking and activity with TAA. Methods Abundance of MMP-2, native and phosphorylated-MT1-MMP, and PKC-delta was measured in aortic tissue from patients with small TAAs (<5 cm; n=8) and large TAAs (>6.5 cm; n=8), and compared to normals (n=8). Cellular localization of green fluorescent protein-tagged MT1-MMP was assessed in aortic fibroblasts isolated from control and 4-week TAA mice. Effects of PKC-mediated phosphorylation on MT1-MMP cellular localization and function (active MMP-2 versus phospo-Smad-2 abundance), was determined following treatment with a PKC activator (phorbol-12-myristate-13-acetate; 100 nM) with and without a PKC-delta-specific inhibitor (Röttlerin, 3 µM). Results Compared to controls, MT1-MMP abundance increased in aortas from both TAA groups. Active MMP-2 was increased only in large TAAs. Abundance of phosphorylated MT1-MMP and activated-PKC-delta was enhanced in small versus large TAAs. MT1-MMP was localized on the plasma membrane in aortic fibroblasts from control mice and in endosomes from TAA mice. PMA treatment induced MT1-MMP-GFP internalization, enhanced phospho-Smad-2, and reduced MMP-2 activation, while Röttlerin pretreatment inhibited these effects. Conclusion Phosphorylation of MT1-MMP mediates its activity through directing cellular localization; shifting its role from MMP-2 activation to intracellular signaling. Targeted inhibition of MT1-MMP may therefore hold therapeutic relevance as a means to attenuate TAA development.