KLF15 maintains contractile phenotype of vascular smooth muscle cells and prevents thoracic aortic dissection by interacting with MRTFB

Thoracic aortic dissection (TAD) is a highly dangerous cardiovascular disorder caused by weakening of the aortic wall, resulting in a sudden tear of the internal face. Progressive loss of the contractile apparatus in vascular smooth muscle cells (VSMCs) is a major event in TAD. Exploring the endogenous regulators essential for the contractile phenotype of VSMCs may aid the development of strategies to prevent TAD. Krüppel-like factor 15 (KLF15) overexpression was reported to inhibit TAD formation; however, the mechanisms by which KLF15 prevents TAD formation and whether KLF15 regulates the contractile phenotype of VSMCs in TAD are not well understood. Therefore, we investigated these unknown aspects of KLF15 function. We found that KLF15 expression was reduced in human TAD samples and β-aminopropionitrile monofumarate-induced TAD mouse model. Klf15KO mice are susceptible to both β-aminopropionitrile monofumarate- and angiotensin II-induced TAD. KLF15 deficiency results in reduced VSMC contractility and exacerbated vascular inflammation and extracellular matrix degradation. Mechanistically, KLF15 interacts with myocardin-related transcription factor B (MRTFB), a potent serum response factor coactivator that drives contractile gene expression. KLF15 silencing represses the MRTFB-induced activation of contractile genes in VSMCs. Thus, KLF15 cooperates with MRTFB to promote the expression of contractile genes in VSMCs, and its dysfunction may exacerbate TAD. These findings indicate that KLF15 may be a novel therapeutic target for the treatment of TAD.

Male-Female Differences in Acute Type B Aortic Dissection

BACKGROUND

Acute type B aortic dissection is a cardiovascular emergency with considerable mortality and morbidity risk. Male-female differences have been observed in cardiovascular disease; however, literature on type B aortic dissection is scarce.

METHODS AND RESULTS

A retrospective cohort study was conducted including all consecutive patients with acute type B aortic dissection between 2007 and 2017 in 4 tertiary hospitals using patient files and questionnaires for late morbidity. In total, 384 patients were included with a follow-up of 6.1 (range, 0.02-14.8) years, of which 41% (n=156) were female. Women presented at an older age than men (67 [interquartile range (IQR), 57-73] versus 62 [IQR, 52-71]; P=0.015). Prior abdominal aortic aneurysm (6% versus 15%; P=0.009), distally extending dissections (71 versus 85%; P=0.001), and clinical malperfusion (18% versus 32%; P=0.002) were less frequently observed in women. Absolute maximal descending aortic diameters were smaller in women (36 [IQR: 33-40] mm versus 39 [IQR, 36-43] mm; P<0.001), while indexed for body surface area diameters were larger in women (20 [IQR, 18-23] mm/m2 versus 19 [IQR, 17-21] mm/m2). No male-female differences were found in treatment choice; however, indications for invasive treatment were different (P<0.001). Early mortality rate was 9.6% in women and 11.8% in men (P=0.60). The 5-year survival was 83% (95% CI, 77-89) for women and 84% (95% CI, 79-89) for men (P=0.90). No male-female differences were observed in late (re)interventions.

CONCLUSIONS

No male-female differences were found in management, early or late death, and morbidity in patients presenting with acute type B aortic dissection, despite distinct clinical profiles at presentation. More details on the impact of age and type of intervention are warranted in future studies.

Transcriptomic Analysis of Tight Junction Proteins Demonstrates the Aberrant Expression and Function of Zona Occludens 2 (ZO-2) Protein in Stanford Type A Aortic Dissection

OBJECTIVE

Thoracic aortic aneurysm dissection (TAAD) represents a cardiac surgery emergency characterized by the disrupted integrity of the aortic wall and is associated with poor prognosis. In this context, the identification of biomarkers implicated in the pathobiology of TAAD is crucial. Our aim in the present original in silico study is to assess the differential gene expression profile of the tight junction proteins (TJPs) in patients with TAAD and to propose novel biomarkers for the diagnosis and prognosis of this disease.

METHODS

We implemented bioinformatics methodology in order to construct the gene network of the TJPs family, identify the differentially expressed genes (DEGs) in pathologic aortic tissue excised from patients with TAAD as compared to healthy aortic tissue, and assess the related biological functions and the associated miRNA families.

RESULTS

Data regarding the transcriptomic profile of selected genes were retrieved and incorporated from three microarray datasets, including 23 TAAD and 20 healthy control samples. A total of 32 TJPs were assessed. The zona occludens 2 (ZO-2) protein encoded by the gene TJP2 was significantly under-expressed in patients with TAAD compared to the control group (p = 0.009). ZO-2 was associated with fair discrimination and calibration traits in predicting the TAAD presentation. CpG islands of ZO-2 were demonstrated. No important difference was found regarding ZO-2 expression between aneurysmal non-dissected and healthy control aortic tissue. Finally, we performed gene set enrichment analysis (GSEA) and uncovered the major biological functions and miRNA families (hsa-miR-155-5p, hsa-miR-1-3p, hsa-miR-2118-5p, hsa-miR-4691-3p, and hsa-miR-1229-3p) relevant to ZO-2.

CONCLUSIONS

These outcomes demonstrated the important role of ZO-2 in the pathobiology of TAAD.

SPINT2 is involved in the proliferation, migration and phenotypic switching of aortic smooth muscle cells: Implications for the pathogenesis of thoracic aortic dissection

Thoracic aortic dissection (TAD) is a severe and extremely dangerous cardiovascular disease. Proliferation, migration and phenotypic switching of vascular smooth muscle cells (SMCs) are major pathogenetic mechanisms involved in the development of TAD. The present study was designed to investigate the expression and potential function of serine peptidase inhibitor Kunitz type 2 (SPINT2) in TAD. The gene expression profile data for ascending aorta from patients with TAD were downloaded from the GEO database with the accession number GSE52093. Bioinformatics analysis using GEO2R indicated that the differentially expressed SPINT2 was prominently decreased in TAD. The expression levels of SPINT2 mRNA and protein in aortic dissection specimens and normal aorta tissues were measured using reverse transcription-quantitative PCR and western blotting. SPINT2 expression was downregulated in clinical samples from aortic dissection specimens of patients with TAD compared with the corresponding expression noted in tissues derived from patients without TAD. In vitro, platelet-derived growth factor BB (PDGF-BB) was applied to induce the isolated primary mouse aortic SMC phenotypic modulation (a significant upregulation in the expression levels of synthetic markers), and the SMCs were infected with the adenoviral vector, Ad-SPINT2, to construct SPINT2-overexpressed cell lines. SMC viability was detected by an MTT assay and SMC proliferation was detected via the presence of Ki-67-positive cells (immunofluorescence staining). To explore the effects of SPINT2 on SMC migration, a wound healing assay was conducted. ELISA and western blotting assays were used to measure the content and expression levels of MMP-2 and MMP-9. The expression levels of vimentin, collagen I, α-SMA and SM22α were measured using western blotting. The PDGF-BB-induced proliferation and migration of SMCs were recovered by SPINT2 overexpression. The increase in the expression levels of SPINT2 reduced the expression levels of active matrix metalloproteinases (MMPs), MMP-2 and MMP-9. Overexpression of SPINT2 suppressed SMC switching from a contractile to a synthetic type, as evidenced by decreased vimentin and collagen I expression levels along with increased α-smooth muscle actin and smooth muscle protein 22-α expression levels. Furthermore, activation of ERK was inhibited in SPINT2-overexpressing SMCs. A specific ERK agonist, 12-O-tetradecanoylphorbol-13-acetate, reversed the SPINT2-mediated inhibition of SMC migration and the phenotypic switching. Collectively, the data indicated that SPINT2 was implicated in the proliferation, migration and phenotypic switching of aortic SMCs, suggesting that it may be involved in TAD progression.

Genetic Overlap of Spontaneous Dissection of Either the Thoracic Aorta or the Coronary Arteries

Ascending thoracic aortic dissection (ATAD) is a well-known vascular cause of sudden death. Spontaneous coronary artery dissections (SCAD) are emerging as an important cause of early-onset myocardial infarction and sudden death. Genetic variants in multiple connective tissue genes have been recognized to underlie ATAD; other genetic variants have similarly been recognized to underlie SCAD. Little data are available regarding any genetic commonality between ATAD and SCAD. Our objective is to determine and characterize any genetic overlap between genes coding for ATAD and SCAD. We identified and reviewed 17 retrospective and prospective genetic studies of thoracic aortic dissection and SCAD published between 2016 and 2022 identified through PubMed and Orbis. Articles highlighting the significant plausible triggers for ATAD or SCAD individually were analyzed. No previous study reviewed both ATAD and SCAD genetics together. Separate lists of causative genes were constructed for ATAD and SCAD-and then commonalities were sought. A Venn diagram was constructed to display the genetic overlap and common physiologic pathways involved. We identified a definite, meaningful overlap of 15 independent genes based on a genome-wide association study or other genetic methods. The associated genetic pathways involved various biologic processes including elastin degradation, smooth muscle cell function, and the TGFβ-pathway. The overlapping genes included the following: COL3A1, TGFB2, SMAD3, MYLK, TGFBR2, TGFBR1, LOX, FBN1, NOTCH1, ELN, COL5A1, COL5A2, COL1A2, MYH11, and TLN1. The corresponding molecular pathways were investigated and correlated for both diseases. We are not aware of other studies searching for genetic commonalities between ATAD and SCAD. We have successfully identified overlapping genes-and their corresponding molecular pathways-for ATAD and SCAD. We hope that these insights will lead to further clinical and scientific understanding of each disease through study of their fundamental commonalities.

Accurate Embolization for Endoleak after F-TEVAR of Thoracic Aortic Dissection by Detachable Coils

OBJECTIVES

To evaluate the efficacy and clinical outcomes of accurate embolization of endoleaks after fenestrated thoracic endovascular aortic repair (F-TEVAR) for thoracic aortic dissections.

METHODS

Twenty patients with endoleaks (17 type I and 3 type II) after fenestrated thoracic endovascular aortic repair (F-TEVAR) were embolized using detachable and ordinary coils. We assessed the success rate and complications of the operation, and its effects, through clinical and CT follow-up.

RESULTS

The mean clinical follow-up duration was 25.68 ± 11.07 months (3-44 months). During follow-up, all endoleaks were completely embolized and aortic remodeling was improved. Secondary endoleaks occurred in four patients who were embolized twice. No other complications or death were reported.

CONCLUSION

Embolization using detachable and ordinary coils is effective and safe for the treatment of endoleaks after fenestrated thoracic endovascular aortic repair.

Pulsatile Deformations of a Conformable Descending Thoracic Aortic Endograft in Aneurysm, Dissection, and Blunt Traumatic Aortic Injury Patients

PURPOSE

This study presents analytic techniques to quantify cardiac pulsatility-induced deformations of thoracic aortic endografts in patients with thoracic aortic aneurysm (TAA), dissection (TAD), and blunt thoracic aortic injury (BTAI) after thoracic endovascular aortic repair (TEVAR).

TECHNIQUE

We analyzed 19 image data sets from 14 patients treated for TAA, TAD, and BTAI with cardiac-gated post-TEVAR CTs. Systolic and diastolic geometric models were constructed and diametric, axial, and bending deformations were quantified. For patients with cardiac-gated pre-op scans, the damping of pulsatile diametric distension was computed. Maximum localized diametric distension was 2.4±1.0%, 4.2±1.7%, and 5.5±1.6%, and axial deformation was 0.0±0.1%, -0.1±0.3%, and 1.1±0.6% in the endografts of TAA, TAD, and BTAI cohorts, respectively. Diametric distension damping from pre- to post-TEVAR was ~50%. Diametric and bending deformations were localized at certain axial positions on the endograft, and the inner curve bends more than the centerline, especially adjacent to overlapping regions.

CONCLUSION

The presented techniques support investigation of multi-axial endograft deformations between disease causes and geometric locations on the device. Discretized quantification of deformation is needed to define device fatigue testing conditions and predict device durability in patients.

CLINICAL IMPACT

This study demonstrates analytic techniques to quantify discretized deformation of thoracic endografts. Cardiac-resolved computed tomography is sometimes acquired for surgical planning and follow-up, however, the dynamic data are not typically used to quantify pulsatile deformations. Our analytic techniques extract the centerline and surface geometry of the stented thoracic aorta during the cardiac cycle, which are used to quantify diametric, axial, and bending deformations to provide better understanding of device durability and impact on the native anatomy.

A Case of Acute Aortic Dissection Presenting With Neurological Symptoms

Aortic dissection (AD) is a life-threatening condition that presents with diverse and atypical symptoms, making it challenging to diagnose. We present a case of a woman in her 40s who presented to the emergency department with collapse, right-sided weakness, agitation, and confusion. Despite efforts, she went into cardiac arrest and died before a definitive diagnosis was made. The post-mortem examination revealed hemopericardium due to dissection of the ascending thoracic aorta as the cause of death. This case highlights the difficulty in diagnosing AD and the need for a high index of suspicion, especially in patients presenting with neurological symptoms and risk factors.

Four-Dimensional Flow MRI for the Evaluation of Aortic Endovascular Graft: A Pilot Study

We aimed to explore the feasibility of 4D flow magnetic resonance imaging (MRI) for patients undergoing thoracic aorta endovascular repair (TEVAR). We retrospectively evaluated ten patients (two female), with a mean (±standard deviation) age of 61 ± 20 years, undergoing MRI for a follow-up after TEVAR. All 4D flow examinations were performed using a 1.5-T system (MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany). In addition to the standard examination protocol, a 4D flow-sensitive 3D spatial-encoding, time-resolved, phase-contrast prototype sequence was acquired. Among our cases, flow evaluation was feasible in all patients, although we observed some artifacts in 3 out of 10 patients. Three individuals displayed a reduced signal within the vessel lumen where the endograft was placed, while others presented with turbulent or increased flow. An aortic endograft did not necessarily hinder the visualization of blood flow through 4D flow sequences, although the graft could generate flow artifacts in some cases. A 4D Flow MRI may represent the ideal tool to follow up on both healthy subjects deemed to be at an increased risk based on their anatomical characteristics or patients submitted to TEVAR for whom a surveillance protocol with computed tomography angiography would be cumbersome and unjustified.

Thoracic Aortic Rupture Post Cardiopulmonary Resuscitation in a Patient With Previous Thoracic Aneurysm Repair

Aortic dissection is characterized by a tear or rupture in the intimal layer of the aorta causing blood to flow between the layers of the arterial wall, thus separating them. While cardiopulmonary resuscitation (CPR) is a life-saving intervention, it can unintentionally contribute to the development or worsening of aortic dissection. The forceful chest compressions involved in CPR can put significant pressure on the fragile aortic wall, potentially leading to a tear or rupture. This highlights the delicate balance between life-saving measures and the potential risks they carry. Though studies have been done on the effects of CPR on the thoracic wall, few reports have studied the effects on the structures that lie in the thoracic cavity. The authors present a 63-year-old with a history of thoracic aneurysm repair who experienced a cardiac arrest while choking on food at home. The patient received CPR and a CT scan done thereafter revealed thoracic dissection and rupture. The patient received medical management in the Intensive Care Unit but eventually expired due to irreversible neurological damage. This highlights the importance of recognizing that CPR can pose a risk for aortic dissection and rupture, particularly in individuals with prior aortic repairs. It emphasizes the need for developing protocols to monitor patients who have undergone aneurysmal repair and adjusting CPR techniques to suit their specific needs. Additionally, further studies are needed to understand how often aortic complications occur after CPR and to provide guidance for follow-up care in patients who have had aortic repairs. By implementing these measures, we can improve outcomes and safety during resuscitation.

Incidental Finding of Thoracic Aortic Dissection in a Patient Post-Coronary Artery Bypass Graft Surgery

Thoracic aortic dissection (TAD) is an uncommon but potentially fatal complication of coronary artery bypass graft (CABG). Most patients present to the emergency room with severe chest pain, shortness of breath, or after a syncopal episode. Asymptomatic patients pose a challenge to diagnosis. The authors present a case of an 82-year-old male, who was found to have an incidental finding of a 5-cm ascending aortic aneurysm with an intimal dissection flap four months after CABG. Extensive workup on possible risk factors such as underlying aortic diseases, genetic conditions, and hypertensive crisis proved noncontributory. Aggressive blood pressure control was achieved, and the patient was observed in the intensive care unit before discharge with follow-up. The purpose of this case report is to alert clinicians of TAD after CABG and highlight the importance of developing a protocol for follow-up and monitoring of patients who have undergone CABG, as complications can be asymptomatic. Early and accurate diagnosis of TAD as a complication of CABG is essential to improving survival rates.

Aortic Dissection From an Intra-aortic Balloon Pump: A Dangerous Complication to Keep in Mind

Despite the benefits of the intra-aortic balloon pump (IABP) being a subject of debate, it remains a widely available and easy-to-use mechanical circulatory support device. Nonetheless, its use is not exempt from complications. Aortic dissection from IABP is an infrequent but deathly complication. We describe a case in which early recognition of the condition led to control through an endovascular approach. A 57-year-old male was admitted for acute decompensated heart failure requiring intravenous inotropic agents. While undergoing assessment for a heart transplant, he developed cardiogenic shock requiring initiation of mechanical circulatory support with an IABP. A few hours after device implantation, the patient developed acute tearing chest pain and was found to have an acute dissection in the descending thoracic aorta. Prompt liaison with the endovascular team led to a thoracic endovascular aortic repair to control the extent of the lesion.

Bicuspid Aortopathy does NOT Require Earlier Surgical Intervention

OBJECTIVES

Guidelines for surgical correction of ascending thoracic aortic aneurysm (ATAA) in bicuspid aortic valve (BAV) patients have oscillated back and forth over the years. In this study, we outline the natural history of the ascending aorta in BAV and TAV (trileaflet aortic valve) ATAA patients followed over time, to ascertain if their behavior differs, and to determine if a different threshold for intervention is required.

METHODS

Aortic diameters and long-term complications (adverse aortic events; AAE) of 2428 patients (554 BAV and 1874 TAV) with ATAA prior to operative repair were reviewed. Growth rates, yearly complication rates, event-free survival (Kaplan-Meier), and risk of complications as a function of aortic size (regression analyses) were calculated. Long-term follow-up and precise cause of death granularity was achieved via a comprehensive six-pronged approach.

RESULTS

Aortic growth rate in BAV- vs. TAV-ATAA patients was 0.20 and 0.17 cm/year, respectively (p=0.009), with the rate increasing with increasing aortic size. Yearly AAE rates increased with ATAA size and were lower for BAV patients. The relative risk of AAE exhibited an exponential increase with aortic diameter. BAV patients had a lower all-cause and ascending aorta specific AAE hazard. Age-adjusted 10-year event free survival was significantly better for BAV patients, and BAV emerged as a protective factor against type A dissection, rupture, and ascending aortic death.

CONCLUSION

The threshold for surgical repair of ascending aneurysm with BAV should not differ from that of TAV. Prophylactic surgery should be considered at 5.0cm for TAV (and BAV) patients at expert centers.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

EphrinB2 promotes the human aortic smooth muscle cell growth and migration via mediating F-actin remodeling

OBJECTIVES

To evaluate the potential effect of EphrinB2 in human thoracic aortic dissection (TAD) and to illustrate the mechanisms governing the role of EphrinB2 in the growth of human aortic smooth muscle cells (HASMC).

METHODS

In the study, EphrinB2 expression was investigated by qRT-PCR and immunohistochemistry in 12 pairs of TAD and adjacent human tissues. HASMCs were used for in vitro experiments. Next, EphrinB2 overexpression and depletion in HASMCs were established by EphrinB2-overexpressing vectors and small interfering RNA, respectively. The transfection efficiency was evaluated by qRT-PCR and Western blot. The effects of overexpression and depletion of EphrinB2 on cell proliferation, migration, and invasion were tested in vitro. Cell Counting Kit-8, flow cytometry and transwell migration/invasion, and wound healing assay were used to explore the function of EphrinB2 on HASMC cell lines. The relationship between EphrinB2 and F-actin was assessed by Western blot, immunofluorescence, and Co-IP.

RESULTS

We found that EphrinB2 was a prognostic biomarker of TAD patients. Moreover, EphrinB2 expression negatively correlated to aortic dissection tissues, and disease incidence of males, suggesting that EphrinB2 might act as a TAD suppressor by promoting proliferation or decreasing apoptosis in HASMC. Next, over-expression of EphrinB2 in HASMC lines drove cell proliferation, migration, and invasion, and inhibited apoptosis while knockdown EphrinB2 showed the opposite phenomenon, respectively. Furthermore, the level of F-actin in mRNA, protein, and distribution in HASMC cell lines highly matched with the expression of EphrinB2, which indicated that EphrinB2 could mediate the HASMC cytoskeleton via inducing F-actin.

CONCLUSIONS

In conclusion, our results first provided the pivotal role of EphrinB2 in HASMC proliferation initiated by mediating F-actin and demonstrated a prognostic biomarker and the potential targets for therapy to prevent thoracic aortic dissection.

The characteristics of thoracic aortic dissection in autopsy-diagnosed individuals: An autopsy study

Thoracic aortic dissection (TAD) is the most common cause of sudden cardiac death associated with aortic diseases. The age of TAD victims in forensic studies is significantly younger than hospitalized patients with TAD, while only a few studies have been conducted on autopsy-diagnosed TAD deceased. A retrospective study was conducted at the Medicolegal Center of Sun Yat-sen University from 1999 to 2019 to address the characteristics of TAD victims. A total of 200 deceased from spontaneous rupture of TAD were assessed, with 165 (82.5%) males and 175 (87.5%) Stanford type A deceased. Our main results showed that compared with patients with TAD diagnosed during their lifetime, individuals diagnosed with TAD until an autopsy showed an earlier onset (43.80 years old) and less accompanied hypertension (<50%). Sudden death was the initial symptom of 32 decedents. Instead of chest/back pain (40 decedents), abdominal pain (59 decedents) was the most common initial symptom, and 42 decedents presented with no accompanying pain. A higher proportion of abdominal pain and the painless symptom was associated with a higher risk of misdiagnosis. Women showed a more atypical clinical presentation and rapid progression than men. Younger decedents showed more pronounced left heart changes. The present study implicated the TAD individuals diagnosed until an autopsy as a particular entity, indicating the urgent need for further investigation on early diagnosis and pathogenesis of patients with TAD with atypical pain and painless or with younger age to reduce the burden of TAD-related sudden death.

Metabolomic Profile Reveals That Ceramide Metabolic Disturbance Plays an Important Role in Thoracic Aortic Dissection

Aims

Thoracic aortic dissection (TAD) is a life-threatening disease with no effective drug therapy thus far. New therapeutic targets and indications for timely surgical intervention are urgently needed. Our aim is to investigate new pathological mechanisms and potential biomarkers of TAD through global metabolomic profiling of aortic aneurysm and dissection patients.

Methods and Results

We performed untargeted metabolomics to determine plasma metabolite concentrations in an aortic disease cohort, including 70 thoracic aortic aneurysm (TAA) and 70 TAD patients, as well as 70 healthy controls. Comparative analysis revealed that sphingolipid, especially its core metabolite C18-ceramide, was significantly distinguished in TAD patients but not in TAA patients, which was confirmed by subsequent quantitative analysis of C18-ceramide in a validation cohort. By analyzing our existing multiomics data in aortic tissue in a murine TAD model and TAD patients, we found that an enhanced ceramide de novo synthesis pathway in macrophages might contribute to the elevated ceramide. Inhibition of the ceramide de novo synthesis pathway by myriocin markedly alleviated BAPN-induced aortic inflammation and dissection in mice. In vitro studies demonstrated that exogenous C18-ceramide promoted macrophage inflammation and matrix metalloprotein (MMP) expression through the NLRP3-caspase 1 pathway. In contrast, inhibition of endogenous ceramide synthesis by myriocin attenuated lipopolysaccharide (LPS)-induced macrophage inflammation.

Conclusions

Our findings demonstrated that ceramide metabolism disturbance might play a vital role in TAD development by aggravating aortic inflammation through the NLRP3 pathway, possibly providing a new target for pharmacological therapy and a potential biomarker of TAD.

Promotional effects of HIF1α and KDM3A interaction on vascular smooth muscle cells in thoracic aortic dissection

Aim: The current study was performed to define the role of KDM3A in thoracic aortic dissection (TAD). Methods: The binding of HIF1α and KDM3A in HES1 was detected by ChIP and dual-luciferase reporter gene assay. Loss and gain-of function assays of HIF1α, KDM3A and HES1 were further performed in Ang-II-induced mouse aortic smooth muscle cell line (MOVAS) cells. Lastly, in vivo TAD models were established. Results: HIF1α was highly expressed in TAD. KDM3A promoted the transcription activation of HES1. HIF1α enhanced the proliferation and migration of Ang-II-induced MOVAS cells, in addition to increasing thoracic aorta dilation to induce TAD formation in vivo. Silencing of HES1 reversed the effects of HIF1α in vivo and in vitro. Conclusion: The findings indicated that interaction between HIF1α and KDM3A enhances the proliferation and migration of MOVAS cells to induce TAD.

Potential Clinical Value of Biomarker-Guided Emergency Triage for Thoracic Aortic Dissection

Aim: Thoracic aortic dissection (TAD) is a high-risk vascular disease. The mortality rate of untreated TADs in 24 h was as high as 50%. Thus, rapid diagnosis of TAD in the emergency department would get patients to the right treatments to save their lives. Methods: We profiled the proteome of aortic tissues from TAD patients using a label-free quantification proteomics method. The differentially expressed proteins were screened and subjected to bioinformatics analysis. Candidate biomarkers were selected and validated in independent serum samples using enzyme-linked immunosorbent assays (ELISAs). The diagnostic values were further predicted via receiver operating characteristic (ROC) curve analysis. Results: A total of 1,141 differentially expressed proteins were identified in aortic tissues from 17 TAD patients and eight myocardial infarction (MI) patients. Six proteins were selected as candidate biomarkers for ELISAs in an independent training set of 20 serum samples (TAD = 10, MI = 10). Of these proteins, four with a P-value < 0.01 were further validated in another independent set of 64 serum samples (TAD = 32, MI = 32) via ELISAs. ITGA2, COL2A1, and MIF had P-values < 0.0001, and their areas under the curve (AUCs) were 0.801 (95% CI: 0.691-0.911), 0.773 (95% CI: 0.660-0.887), and 0.701 (95% CI: 0.574-0.828), respectively. Conclusion: ITGA2, COL2A1, and MIF were identified as promising biomarkers for discriminating TAD from emergency patients with severe chest pain. Biomarker-guided emergency triage could further shorten the time for patients to get more effective treatments.

nnResearch progress on B cells and thoracic aortic aneurysm/dissection

Thoracic aortic aneurysm/dissection (TAAD) is a rare cardiovascular disease characterized by acute onset, rapid progression and high morbidity and mortality. One of the crucial factors leading to TAAD is the inflammatory response, which is regulated by many immune cell subgroups, including B cells. Compared with normal aortic tissue, the number of B cells in the aortic tissue of TAAD patients is significantly higher. Activated B cells participate in the vascular immune inflammatory response by producing antibodies and inflammatory factors and activating the complement system. These effects can lead to collagen degradation and aortic wall remodeling, both of which are the main pathologic characteristics of TAAD. Therefore, B cells play a key role in the occurrence and development of TAAD. B cells can be divided into B1 cells, B2 cells and regulatory B cells, which have different mechanisms of action in TAAD. This article will review the role of B cells in TAAD from the perspective of three different subtypes of B cells.

Construction and Integrated Analysis of Competitive Endogenous Long Non-Coding RNA Network in Thoracic Aortic Dissection

Background

Long non-coding RNAs (lncRNAs) can act as a competitive endogenous RNA (ceRNA) to regulate gene expression by sequestering the microRNA (miRNA). However, the lncRNA-miRNA-mRNA ceRNA network in thoracic aortic dissection (TAD) has been rarely documented.

Methods

Three Gene Expression Omnibus (GEO) datasets were used to detect differentially expressed mRNAs, miRNAs, and lncRNAs in TAD. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted for the differentially expressed mRNAs. A protein–protein interaction network for differentially expressed mRNAs was also constructed, and hub genes were identified. We established a ceRNA network of TAD based on the differentially expressed miRNAs, mRNAs and lncRNAs, and verified our results using an independent dataset and quantitative real-time PCR (qRT-PCR).

Results

In TAD, 267 lncRNAs, 81 miRNAs, and 346 mRNAs were identified as differentially expressed. The established ceRNA network consisted of seven lncRNA nodes, three mRNA nodes, and three miRNA nodes, and the expression of miRNAs in TAD was opposite to that of lncRNAs and mRNAs. Subsequently, an independent GEO dataset and qRT-PCR were used to validate the expression of three mRNAs. In addition, the expression differences in SLC7A5, associated miRNA and lncRNA were verified. According to gene set enrichment analysis of SLC7A5, the most significant KEGG pathway was considerably enriched in spliceosome and pentose phosphate pathway.

Conclusion

We established a novel ceRNA regulatory network in TAD, which provides valuable information for further research in the molecular mechanisms of TAD.

Management of Descending Thoracic Aortic Diseases: Similarities and Differences Among Cardiovascular Guidelines

Cardiovascular societies have developed recommendations regarding the management of thoracic aortic diseases. While improvements in treatment have been observed during the past decade in regard to patient selection, thoracic endovascular aortic repair (TEVAR) and associated techniques, and high-volume centralization, the broad expansion of TEVAR has raised considerations about its indications, appropriateness, limitations, and application. The aim of this systematic review was to assess the similarities and differences among current cardiovascular societies' guidelines for the management of thoracic aortic diseases. The MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched from January 2009 to May 2020. The initial search identified 990 articles. After exclusion of duplicate or inappropriate articles, the final analysis included 5 articles from cardiovascular societies published between 2010 and 2020. Selected controversial topics were analyzed, including diagnosis, imaging, spinal cord ischemia prevention, and management of the most important thoracic aortic pathologies. The analysis included data concerning the therapeutic approach in acute and chronic type B aortic dissection, penetrating aortic ulcer, intramural hematoma, thoracic aortic aneurysm, and traumatic aortic injury, as well a discussion of inflammatory aneurysms, aortitis, and genetic syndromes. The review presents consistent and controversial recommendations, as well as "gray zone" issues that need further investigation. There was significant overlap and agreement among the 5 societies regarding the management of thoracic aortic diseases. Especially in dissection and aneurysm management, TEVAR has established its role as the treatment of choice. However, robust evidence is still needed in many aspects of the management of thoracic aortic pathologies.

[Gene mutation analysis of 19 Uighur families with aortic disease in Kashgar, China]

OBJECTIVE

To explore genetic mutation types and their correlation with clinical phenotypes in Uighur patients with aortic disease in Kashgar (Xinjiang Uighur Autonomous Region, China).

METHODS

We examined 37 pathogenic genes in 19 Uighur families with aortic diseases including Marfan syndrome from Kashgar using next generation sequencing, and the results were confirmed by Sanger sequence in the first relatives.

RESULTS

This study included 19 families with aortic diseases, in whom a total of 23 variants were identified, and 11 (57.89%) probands had one or more variants. Among them, definite pathogenic mutation was detected in one patient (5.26%), variants of uncertain significance (VUS) were found in 8 (42.11%), and benign/likely benign variants were detected in 7 (36.84%). The 23 variants identified included one (5.26%) pathogenic variant, 14 (60.87%) VUS, and 8 (34.78%) benign/likely benign variants. The 14 VUS were analyzed by prediction with SIFT and Polyphen2 HDIV, which identified 6 (42.86%) variants as deleterious/possibly damaging; all the 8 benign/likely benign variants were predicted to be deleterious/possibly damaging.

CONCLUSIONS

We detected 23 genetic variants in the 19 Uighur families with aortic diseases, and 22 of these variants remain to be verified by more patient data in future studies.

Insulin-like growth factor-binding protein 3 inhibits angiotensin II-induced aortic smooth muscle cell phenotypic switch and matrix metalloproteinase expression

NEW FINDINGS

What is the central question of this study? Insulin-like growth factor 1 and its major binding protein insulin-like growth factor binding protein 3 (IGFBP3) are involved in collagen deregulation in several cardiovascular diseases: what is the role of IGFBP3 in thoracic aortic dissection and does it regulate aortic smooth muscle cells' phenotypic switch? What is the main finding and its importance? IGFBP3 inhibits aortic smooth muscle cells' phenotypic switch from a contractile to a synthetic phenotype, decreases matrix metalloproteinase 9 activation and suppresses elastin degradation. These findings provide a better understanding of the pathogenesis of thoracic aortic dissection.

ABSTRACT

Thoracic aortic dissection (TAD) is characterized by aortic media degeneration and is a highly lethal disease. An aortic smooth muscle cell (AoSMC) phenotypic switch is considered a key pathophysiological change in TAD. Insulin-like growth factor binding protein 3 (IGFBP3) was found to be downregulated in aortic tissues of TAD patients. The present work aimed to study the function of IGFBP3 in AoSMCs' phenotypic switch and matrix metalloproteinase (MMP) expression. We established a mouse model of TAD by angiotensin (Ang) II infusion to β-aminopropionitrile-administrated mice, and found decreased IGFBP3 expression accompanied by aortic dilatation and elastin degradation in vivo. Further, mouse (m)AoSMCs were isolated from mouse thoracic aorta and treated with Ang II. Ang II induced downregulation of IGFBP3 in vitro. To further study the function of IGFBP3, primary mAoSMCs were infected with adenovirus expressing IGFBP3 followed by Ang II induction. Enforced upregulation of IGFBP3 decreased MMP9 expression and activation as well as increasing tissue inhibitor of metalloproteinase (TIMP) 1 expression in Ang II-induced mAoSMCs. No difference was observed in MMP2 and TIMP3 expression. IGFBP3 suppressed subsequent Ang II-induced elastin degradation in vitro. IGFBP3 inhibited Ang II-induced mAoSMCs' phenotypic switch as evidenced by increased smooth muscle actin α-2 (ACTA2) and myosin heavy chain 11 (MYH11) expression and decreased secreted phosphoprotein 1 (SPP1) and vimentin expression. Taken together, the present study demonstrates the role of IGFBP3 in preserving AoSMCs' contractile state and reducing MMP9 activation and thus promoting elastic fibre synthesis, which provides a better understanding of the pathogenesis of TAD.

Thoracic Aortic Dissection in Tetralogy of Fallot: A Review of the National Inpatient Sample Database

Background

Thoracic aortic aneurysm is common in patients with tetralogy of Fallot (TOF); the incidence of thoracic aortic dissection (TAD) is unknown, but generally considered to be uncommon. The purpose of this study was to determine incidence and risk factors for TAD in TOF patients.

Methods and Results

This work is a retrospective review of the National Inpatient Sample (NIS) database for cases of ascending TAD among all hospital admissions in adults with TOF, 2000–2014. Of 18 353 admissions in TOF patients, 11 (0.06%; 6 per 10 000 admissions) of these were TAD‐related admissions. For the TAD‐related admissions, mean age was 49.8±7.2 years; aortic surgical interventions were performed during 8 of the admissions, and overall in‐hospital mortality was 45% (5 of 11). Risk factors associated with TAD‐related admission were age >60 years (odds ratio, 2.41; 95% CI, 1.23–3.25; P=0.013), male sex (odds ratio, 6.91; 95% CI, 4.85–8.54; P<0.001), and hypertension (odds ratio, 1.74; 95% CI, 1.06–3.19; P=0.037).

Conclusions

This is the first population‐based study of TAD outcomes in patients with TOF, and it showed a low risk of TAD in this population. This has important clinical implication with regard to surveillance and surgical intervention. Given that prevalence of thoracic aortic aneurysm is higher in TOF patients compared with the general population; therefore, making clinical decisions based on outcomes data and practice guidelines derived from patients with degenerative and bicuspid aortic valve–related aortopathies may lead to overtreatment. Further studies are required to better understand the pathobiology of this disease in order to make evidence‐based recommendations for surveillance and treatment.

Efficient detection of differentially methylated regions in the genome of patients with thoracic aortic dissection and association with MMP2 hypermethylation

DNA methylation is known to regulate the expression of numerous genes but its role in the pathogenesis of thoracic aortic dissection (TAD) has remained largely elusive. In the present study, the DNA methylome of patients with TAD was analyzed using a methylation microarray and bisulfite pyrosequencing was used to determine whether the hypermethylation of matrix metalloproteinase 2 (MMP2) specifically is associated with TAD. Chip-based whole-DNA methylome analysis was performed on 4 male patients with TAD and 4 male healthy controls using an Illumina HumanMethylation EPIC 850K BeadChip. The resulting data were analyzed by clustering and principal component analysis, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed on the differentially methylated genes to interrogate their biological functions. Compared to the healthy controls, 3,362 loci were differentially methylated in the patients with TAD with a statistical significance of P<0.05, while 1,223 loci had a significance of P<0.01. Among these loci, 2,019 were hypermethylated and 1,343 were hypomethylated. From GO analysis within the biological process category, the MMP2, MMP14 and WNT2B genes were identified. enrichment was observed for loci involved in cellular component organization, enzyme-linked receptor protein signaling pathways (potentially having a key role in the development of cardiopulmonary function disorders) and vascular reconstruction. Bisulfite pyrosequencing of plasma samples indicated significantly increased methylation (P<0.01) of the CpG site at position 2 in the promoter of MMP2 in the TAD group relative to the healthy controls, and the mean methylation level of four CpG sites on the MMP2 gene in the TAD group was slightly higher than that in the control group, but not significantly. Hypermethylation of the MMP2 promoter may be a promising novel diagnostic and prognostic biomarker for TAD. Future studies on the epigenetics of biomarkers linked to vascular reconstruction and immune function may provide further insight into the pathogenesis and progression of TAD.

Downregulation of HDAC1 suppresses media degeneration by inhibiting the migration and phenotypic switch of aortic vascular smooth muscle cells in aortic dissection

Although much progress has been made in the diagnosis and treatment of thoracic aortic dissection (TAD), the overall morbidity and mortality rates of TAD are still high. Therefore, the molecular pathogenesis and etiology of TAD need to be elucidated. In this study, we found that histone deacetylase 1 (HDAC1) expression is dramatically higher in the aortic wall of patients with TAD (than that in a normal group) and negatively correlates with the levels of the vascular smooth muscle cell (SMC) contractile-phenotype markers. Knockdown of HDAC1 upregulated both smooth muscle 22 α (SM22α) and α-smooth muscle actin (α-SMA) in platelet-derived growth factor (PDGF)-BB-treated and -untreated SMCs. In addition, the knockdown of HDAC1 markedly decreased SMC viability and migration in contrast to the control group under the conditions of quiescence and PDGF-BB treatment. We also showed that the expression of polycystic kidney disease 1 (PKD1) is decreased in the aortic wall of patients with TAD and negatively correlates with HDAC1 expression. Overexpressed PKD1 obviously increased SM22α and α-SMA expression and reduced the viability and migration of SMCs, but these effects were attenuated by HDAC1. Furthermore, we demonstrated that HDAC1 serves as an important modulator of the migration and phenotypic switch of SMCs by suppressing the PKD1- mammalian target of the rapamycin signaling pathway. HDAC1 downregulation inhibited media degeneration and attenuated the loss of elastic-fiber integrity in a mouse model of TAD. Our results suggest that HDAC1 might be a new target for the treatment of a macrovascular disease such as TAD.

Endovascular repair during complex thoracic aortic dissection using a micropore stent graft: Midterm follow-up clinical outcomes

Objective

This study explored the clinical efficacy and hemodynamic effects of the micropore stent graft (MSG) that could promote aortic remodeling and preserve important organ branches.

Methods

We conducted a retrospective analysis of 26 patients who underwent endovascular repair using an MSG for DeBakey types I and III TAD at our center between December 2014 and December 2017. The main efficacy parameters were rupture of the false lumen or dissection‐related death, conversion to open repair, secondary reintervention, branch vessel patency, and the hemodynamic effects of TAD at 12 months.

Results

Dissection rupture, dissection‐related mortality, conversion to open repair, and secondary reintervention rates at 12 months were 0, 3.9, 0, and 0%, respectively. In the 24 patients with more than 6 months of follow‐up, micropore stents were implanted to cover 39 openings in aortic arch branches, 91.7% (22/24) presented with complete thrombosis in the false lumen, 8.3% (2/24) presented with partial thrombosis in the false lumen, 35.2% (6/17) presented with a thrombus in the false lumen that was completely absorbed, and all 39 branches were patent. After surgery, pressure peak value and fluctuation along with the degree and range of unstable blood flow in the aortic lumen decreased.

Conclusions

For type I and type III thoracic artic dissection, endovascular treatment with an MSG may be a safe and effective treatment option with a good midterm outcome.

Aortic progression and reintervention in patients with pathogenic variants after a thoracic aortic dissection

OBJECTIVE

To evaluate aortic disease progression and reintervention after an initial thoracic aortic dissection in pathogenic variant carriers.

METHODS

Of 175 participants diagnosed with thoracic aortic dissection, 31 had a pathogenic variant (pathogenic group) across 6 genes (COL3A1, FBN1, LOX, PRKG1, SMAD3, TGFBR2) identified by whole exome sequencing. Those with benign or normal variants (benign/normal group, n = 144) comprised the control group. Clinical data were collected through medical record review (1985-2018) and supplemented with the National Death Index database (December 2018).

RESULTS

The entire cohort (n = 175) consisted of 108 type A aortic dissections and 67 type B aortic dissections, similarly distributed between groups. The pathogenic group was significantly younger (43 vs 56 years, P < .0001) and had significantly more aortic root replacements and similar extents of arch replacement at initial type A aortic dissection repair. The median follow-up time was 7.5 (4.6-12) years. After initial treatment, the pathogenic group required significantly more aortic reinterventions (median 1 vs 0, P < .0001) and mean cumulative aortic reinterventions for each patient (10 years: 1 vs 0.5, P = .029). Both incidence rate (12%/year vs 1.2%/year, P = .0001) and cumulative incidence of reinterventions (9 years: 70% vs 6%, P < .0001) for the preserved native aortic root were significantly higher in the pathogenic group, but were similar for the preserved native aortic arch and distal aorta between groups. Ten-year survival was similar in the pathogenic and benign/normal groups (92% vs 85%).

CONCLUSIONS

Aggressive aortic root replacement and similar arch management should be considered in pathogenic variant carriers at initial type A aortic dissection repair compared with benign/normal variant carriers.

Clinical Validity of Genes for Heritable Thoracic Aortic Aneurysm and Dissection

BACKGROUND

Thoracic aortic aneurysms progressively enlarge and predispose to acute aortic dissections. Up to 25% of individuals with thoracic aortic disease harbor an underlying Mendelian pathogenic variant. An evidence-based strategy for selection of genes to test in hereditary thoracic aortic aneurysm and dissection (HTAAD) helps inform family screening and intervention to prevent life-threatening thoracic aortic events.

OBJECTIVES

The purpose of this study was to accurately identify genes that predispose to HTAAD using the Clinical Genome Resource (ClinGen) framework.

METHODS

We applied the semiquantitative ClinGen framework to assess presumed gene-disease relationships between 53 candidate genes and HTAAD. Genes were classified as causative for HTAAD if they were associated with isolated thoracic aortic disease and were clinically actionable, triggering routine aortic surveillance, intervention, and family cascade screening. All gene-disease assertions were evaluated by a pre-defined curator-expert pair and subsequently discussed with an expert panel.

RESULTS

Genes were classified based on the strength of association with HTAAD into 5 categories: definitive (n = 9), strong (n = 2), moderate (n = 4), limited (n = 15), and no reported evidence (n = 23). They were further categorized by severity of associated aortic disease and risk of progression. Eleven genes in the definitive and strong groups were designated as "HTAAD genes" (category A). Eight genes were classified as unlikely to be progressive (category B) and 4 as low risk (category C). The remaining genes were recent genes with an uncertain classification or genes with no evidence of association with HTAAD.

CONCLUSIONS

The ClinGen framework is useful to semiquantitatively assess the strength of gene-disease relationships for HTAAD. Gene categories resulting from the curation may inform clinical laboratories in the development, interpretation, and subsequent clinical implications of genetic testing for patients with aortic disease.

Surgical repair of bicuspid aortopathy at small diameters: Clinical and institutional factors

OBJECTIVE

Bicuspid aortic valve is a common risk factor for thoracic aortic aneurysm and dissection. Guidelines for elective ascending aortic intervention (AAI) in bicuspid aortic valve are derived from limited evidence, and the extent of practice variation due to patient and provider characteristics is unknown. Using data from 2 large cardiovascular registries, we investigated factors that influence decisions for AAI.

METHODS

All bicuspid aortic valve cases with known aortic diameters and surgical status were included. We used multivariable logistic regression to profile predictors of isolated aortic valve replacement (AVR) or AVR+AAI, stratified by patient characteristics, surgical indications, and institution.

RESULTS

We studied 2861 subjects at 18 institutions from 1996 to 2015. The median aortic diameter of patients who underwent AVR+AAI varied widely across institutions (39-52 mm). Aortic diameters were <45 mm in 38% of patients undergoing AVR+AAI. Patients who underwent AAI at <45 mm, compared with those managed nonoperatively, were younger (54 ± 13 vs 61 ± 15 years; P < .001) with more frequent aortic stenosis (53% vs 28%; P < .001) and regurgitation (52% vs 18%; P < .001).

CONCLUSIONS

Clinical and institutional factors influence the timing of AAI and are associated with significant variability in ascending aortic diameter at AAI across institutions. More than one third of patients with a bicuspid aortic valve undergo AAI at aortic diameters <45 mm. Long-term outcomes of this subgroup of patients, who may manifest earlier and more severe disease, are needed to determine the risk-benefit ratio of routine aortic interventions at smaller diameters.

Involvement of B cells in the pathophysiology of β-aminopropionitrile-induced thoracic aortic dissection in mice

Thoracic aortic dissection (TAD) is a life-threatening disease that is characterized by an inflammatory response. Innate and cellular immunity has long been known to be involved in TAD, but the role of humoral immunity in the pathophysiology of TAD remains unknown. We administered the lysyl oxidase inhibitor β-aminopropionitrile (BAPN; 1 g/kg/day) in 3-week-old male C57BL/6J mice for 4 weeks to establish an animal model of TAD. Animals that died were immediately dissected. Animals that survived were sacrificed on days 7, 14, and 28 after BAPN challenge. The incidence and rupture rates of BAPN-induced TAD were 90% (9/10) and 70% (7/10), respectively, at 28 days. Victoria blue-nuclear fast red staining of aortic tissue revealed elastic lamellae destruction and the formation of a false lumen in the BAPN group. Hematoxylin-eosin staining revealed the infiltration of both plasmacytoid mononuclear cells and polymorphonuclear inflammatory cells in TAD tissues. Enzyme-linked immunosorbent assay and immunohistochemistry indicated that plasma immunoglobin M (IgM) and IgG were elevated at 7, 14, and 28 days, and CD19-positive B cells infiltrated into the adventitia of aortic tissue in BAPN-treated mice. The transcriptional analysis showed an increase in the expression of B cell receptor signaling-associated genes. These results indicate that B cells and immunoglobulins might participate in the pathogenesis of TAD, suggesting that humoral immunity may be a possible therapeutic target for TAD.

MicroRNA-134-5p Regulates Media Degeneration through Inhibiting VSMC Phenotypic Switch and Migration in Thoracic Aortic Dissection

Abnormal phenotypic switch, migration, and proliferation of vascular smooth muscle cells (VSMCs) are hallmarks for pathogenesis of thoracic aortic dissection (TAD). In the current study, we identified miR-134-5p as a critical regulator controlling human VSMC phenotypic switch and migration to investigate whether miR-134-5p affects human VSMC functions and development of TAD. Using miRNA microarray of aorta specimens from 12 TAD and 12 controls, we identified miR-134-5p, which was significantly downregulated in TAD tissues. With qPCR detection, we found that miR-134-5p was also evidently decreased in human AoSMCs. Ectopic expression of miR-134-5p obviously promoted VSMC differentiation and expression of contractile markers, such as α-SMA, SM22α, and MYH11. miR-134-5p potently inhibited PDGF-BB-induced VSMC phenotypic switch and migration. We further identified STAT5B and ITGB1 as downstream targets of miR-134-5p in human VSMCs and proved them to be mediators in VSMC phenotypic switch and progression of TAD. Finally, Ad-miR-134-5p obviously suppressed the aorta dilatation and vascular media degeneration by 39% in TAD mice after vascular injury induced by Ang II. Our findings revealed that miR-134-5p was a novel regulator in vascular remodeling and pathological progress of TAD via targeting STAT5B/ITGB1 expression. Targeting miR-134-5p or its downstream molecules in VSMCs might develop new avenues in clinical treatment of TAD.

Simple renal cysts and bovine aortic arch: markers for aortic disease

Objective

This study aimed to assess the prevalence of thoracic aortic disease (TAD) and abdominal aortic aneurysms (AAA) among patients with simple renal cyst (SRC) and bovine aortic arch (BAA).

Methods

Through a retrospective search for patients who underwent both chest and abdominal CT imaging at our institution from 2012 to 2016, we identified patients with SRC and BAA and propensity score matched them to those without these features by age, gender and presence of hypertension, hyperlipidaemia, diabetes and chronic kidney disease.

Results

Of a total of 35 498 patients, 6366 were found to have SRC. Compared with the matched population without SRC, individuals with SRC were significantly more likely to have TAD (10.1% vs 3.9%), ascending aortic aneurysm (8.0% vs 3.2%), descending aortic aneurysm (3.3% vs 0.9%), type A aortic dissection (0.6% vs 0.2%), type B aortic dissection (1.1% vs 0.3%) and AAA (7.9% vs 3.3%). The 920 patients identified with BAA were significantly more likely to have TAD (21.8% vs 4.5%), ascending aortic aneurysm (18.4% vs 3.2%), descending aortic aneurysm (6.5% vs 2.0%), type A aortic dissection (1.4% vs 0.4%) and type B aortic dissection (2.4% vs 0.7%) than the matched population without BAA. SRC and BAA were found to be significantly associated with the presence of TAD (OR=2.57 and 7.69, respectively) and AAA (OR=2.81 and 2.56, respectively) on multivariable analysis.

Conclusions

This study establishes a substantial increased prevalence of aortic disease among patients with SRC and BAA. SRC and BAA should be considered markers for aortic aneurysm development.

Aortic stiffness in families with inherited non-syndromic thoracic aortic disease

BACKGROUND

In families with an inherited form of non-syndromic thoracic aortic disease (TAAD), aortic diameter alone is not a reliable marker for disease occurrence or progression. To identify other parameters of aortic function, we studied aortic stiffness in families with TAAD. We also compared diameter measurements obtained by transthoracic echocardiography (TTE) and magnetic resonance imaging (MRI).

METHODS

Seven families, including 116 individuals, with non-syndromic TAAD, were studied. The aortic diameter was measured by TTE and MRI. Aortic stiffness was assessed as local distensibility in the ascending aorta and as regional and global pulse wave velocity (PWV). Individuals with a dilated thoracic aorta (n = 21) were compared with those without aortic dilatation (n = 95).

RESULTS

Ascending aortic diameter measured by TTE strongly correlated with the diameter measured by MRI (r² = 0.93). The individuals with dilated aortas were older than those without dilatation (49 vs 37 years old). Ascending aortic diameter increased and distensibility decreased with increasing age; while, PWV increased with age and diameter. Some young subjects without aortic dilatation showed increased aortic stiffness. Individuals with a dilated thoracic aorta had significantly higher PWV and lower distensibility, measured by MRI than individuals without dilatation.

CONCLUSIONS

Diameters measured with TTE agree with those measured by MRI. Aortic stiffness might be a complementary marker for aortic disease and progression when used with aortic diameter, especially in young individuals.

Effect of Resident Involvement on Morbidity and Mortality Following Thoracic Endovascular Aortic Repair

OBJECTIVE

To evaluate the effect of resident involvement in thoracic endovascular aortic repair (TEVAR).

SUMMARY OF BACKGROUND DATA

Although the influence of resident intraoperative involvement in several types of surgical procedures has been reported, the effect of resident participation in TEVAR is unknown. We evaluated patient outcomes in resident-involved TEVAR procedures.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was analyzed for TEVAR performed from 2010 to 2012. Current procedural terminology codes were used to identify adult patients (≥18 y) who underwent TEVAR. Patients were grouped into those with and without resident involvement. Descriptive and binomial logistic statistics were used to determine the effect of resident involvement on post-TEVAR outcomes. p values < 0.05 were considered statistically significant.

RESULTS

A total of 676 patients met inclusion criteria for this study. Of these, 517 (76.5%) had residents involved. Overall mortality was 9.8%, with no significant difference between the 2 groups (p = 0.88). Resident involvement was not a significant predictor of any post-TEVAR complication. Postoperative pneumonia (3.5% vs 6.9%, p = 0.06), prolonged mechanical ventilation (11.8% vs 11.9%, p = 0.96), stroke (2.7% vs 5.7%, p = 0.07), urinary tract infection (3.3% vs 4.4%, p = 0.50), progressive renal insufficiency (1.2% vs 2.5%, p = 0.22), acute renal failure (4.1% vs 5.0%, p = 0.60), cardiac arrest (2.9% vs 5.0%, p = 0.20), myocardial infarction (1.7% vs 1.9%, p = 0.91), deep venous thrombosis (1.7% vs 1.3%, p = 0.67), red blood cells transfusions (29.2% vs 36.5%, p = 0.08), sepsis (2.9% vs 4.4%, p = 0.35), septic shock (1.9% vs 3.8%, p = 0.18), and unplanned reintubation (8.7% vs 9.4%, p = 0.78) were not significantly affected. Additionally, resident involvement did not significantly affect operative time (176.1 ± 122.8 min vs 180.3 ± 119.1 min, p = 0.71) and anesthesia time (282.1 ± 146.6 min vs 278.3 ± 140.5 min, p = 0.78).

CONCLUSIONS

The participation of residents in TEVAR did not significantly affect all 30-day patient outcomes. Resident involvement in TEVAR is safe and should be encouraged.

MINI ABSTRACT

This study evaluated the effect of resident participation on postoperative outcomes of thoracic endovascular aortic repair (TEVAR) using the American College of Surgeons National Surgical Quality Improvement (ACS-NSQIP) database. Results showed that resident involvement in TEVAR does not negatively affect patient outcomes.

Results of next-generation sequencing gene panel diagnostics including copy-number variation analysis in 810 patients suspected of heritable thoracic aortic disorders

Simultaneous analysis of multiple genes using next-generation sequencing (NGS) technology has become widely available. Copy-number variations (CNVs) in disease-associated genes have emerged as a cause for several hereditary disorders. CNVs are, however, not routinely detected using NGS analysis. The aim of this study was to assess the diagnostic yield and the prevalence of CNVs using our panel of Hereditary Thoracic Aortic Disease (H-TAD)-associated genes. Eight hundred ten patients suspected of H-TAD were analyzed by targeted NGS analysis of 21 H-TAD associated genes. In addition, the eXome hidden Markov model (XHMM; an algorithm to identify CNVs in targeted NGS data) was used to detect CNVs in these genes. A pathogenic or likely pathogenic variant was found in 66 of 810 patients (8.1%). Of these 66 pathogenic or likely pathogenic variants, six (9.1%) were CNVs not detectable by routine NGS analysis. These CNVs were four intragenic (multi-)exon deletions in MYLK, TGFB2, SMAD3, and PRKG1, respectively. In addition, a large duplication including NOTCH1 and a large deletion encompassing SCARF2 were detected. As confirmed by additional analyses, both CNVs indicated larger chromosomal abnormalities, which could explain the phenotype in both patients. Given the clinical relevance of the identification of a genetic cause, CNV analysis using a method such as XHMM should be incorporated into the clinical diagnostic care for H-TAD patients.

Genes Associated with Thoracic Aortic Aneurysm and Dissection: 2018 Update and Clinical Implications

Thoracic aortic aneurysms, with an estimated prevalence in the general population of 1%, are potentially lethal, via rupture or dissection. Over the prior two decades, there has been an exponential increase in our understanding of the genetics of thoracic aortic aneurysm and/or dissection (TAAD). To date, 30 genes have been shown to be associated with the development of TAAD and ∼30% of individuals with nonsyndromic familial TAAD have a pathogenic mutation in one of these genes. This review represents the authors' yearly update summarizing the genes associated with TAAD, including implications for the surgical treatment of TAAD. Molecular genetics will continue to revolutionize the approach to patients afflicted with this devastating disease, permitting the application of genetically personalized aortic care.

Circular RNA expression profile and potential function of hsa_circRNA_101238 in human thoracic aortic dissection

Objective

To assess the circular RNAs (circRNAs) expression profile and explore the potential functions in human thoracic aortic dissection (TAD).

Methods

The differentially expressed circRNAs profiles of the aortic segments between human type A TAD patients (n=3) and age-matched normal donors (NA; n=3) were analyzed using the Arraystar human circRNAs microarray. Quantitative real-time PCR was used to validate the expression pattern of circRNAs, parental genes, and hsa-miR-320a; Western blotting confirmed MMP9 expression with additional samples. Bioinformatic tools including network analysis, Gene ontology, and KEGG pathway analysis were utilized.

Results

Among 8,173 detected circRNA genes, 156 upregulated and 106 downregulated significantly in human TAD as compared to NA (P£0.05). Quantitative real-time PCR showed an elevated expression of the upregulated hsa_circRNA_101238, hsa_circRNA_104634, hsa_circRNA_002271, hsa_circRNA_102771, hsa_circRNA_104349, COL1A1, and COL6A3 and reduced of the downregulated hsa_circRNA_102683, hsa_circRNA_005525, hsa_circRNA_103458, and FLNA. Gene ontology analysis revealed that the parental genes favored several pathological processes, such as negative regulation of cell proliferation and extracellular matrix organization. The circRNA-miRNA co-expression network predicted that 33 circRNAs might interact with at least one target miRNAs altered in TAD. KEGG pathway analysis revealed that 28 altered miRNAs were enriched on focal adhesion and vascular smooth muscle contraction. The hsa_circRNA_101238-miRNA-mRNA network indicated the highest degree of hsa-miR-320a. Quantitative real-time PCR and Western blot manifested the low expression of hsa-miR-320a and high of MMP9 in human TAD tissues, respectively.

Conclusions

This study revealed hundreds of differentially expressed circular RNAs in human TAD, suggesting that hsa_circRNA_101238 might inhibit the expression of hsa-miR-320a and increase that of MMP9 in TAD.

Successful Repair of Acute Type B and Retrograde Type A Aortic Dissection With Kidney Ischemia

Acute dissection of thoracic aorta carries a risk of renal ischemia followed by the development of a kidney failure. The optimal surgical and nonsurgical management of these patients, timing of intervention, and the factors predicting renal recovery are not well delineated and remain controversial. We present a case of acute type B thoracic aortic dissection with left kidney ischemia. Evaluation of renal function was performed by the means of internationally accepted Risk, Injury, Failure, Loss of kidney function, End stage kidney disease and Acute Kidney Injury Network classifications for acute kidney injury, renal duplex sonography, and intravascular ultrasound that demonstrated left renal artery dissection with a flap completely compressing the true lumen. The patient underwent thoracic endovascular aortic repair and left renal artery stent and recovered well. Six months later, at the follow-up visit, retrograde type A aortic dissection was found, which was successfully repaired. Reversal of renal ischemia after aortic dissection depends on the precise assessment of renal function and prompt intervention.

Point of Care Echocardiography in an Acute Thoracic Dissection with Tamponade in a Young Man with Chest Pain, Tachycardia, and Fever

BACKGROUND

Although thoracic aortic dissections are uncommon in young patients, they must be considered in the differential diagnosis in the presence of chest pain and abnormal vital signs. Although computed tomography angiography is the test of choice for thoracic dissection in the emergency department, point of care (POC) transthoracic echocardiography has a high specificity in the diagnosis of this disease. It is especially helpful in patients with proximal ascending dissections in the presence of a pericardial effusion.

CASE REPORT

This case report illustrates a young patient presenting with chest pain, persistent tachycardia, and fever with a presumed upper respiratory infection who had an ascending thoracic dissection with tamponade discovered on POC echocardiography. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: POC echocardiography should be an important part of the algorithm in young patients presenting with chest pain and abnormal vital signs that do not improve with supportive measures. Definitive care in patients who present with a thoracic aortic dissection in the presence of cardiac tamponade diagnosed on POC echocardiography should not be delayed in order to wait for other imaging methods to be performed. POC echocardiography may expedite care and treatment in young patients presenting with this deadly disease.

Involvement of Oct4 in the pathogenesis of thoracic aortic dissection via inducing the dedifferentiated phenotype of human aortic smooth muscle cells by directly upregulating KLF5

OBJECTIVE

To investigate the expression of Oct4 in human thoracic aortic dissection (TAD) and the regulation mechanisms of Oct4 on phenotype transition of human aortic smooth muscle cells (HASMCs).

METHODS

Aortic samples from TAD patients (n = 12) and organ donors (n = 6) were collected. qRT-PCR, western blot, and immunohistochemistry were performed to identify Oct4 expression in aortic media. Immunofluorescence was performed to analyze Oct4 expression in primary HASMCs. Oct4A and Oct4B isoforms were detected. Gain-of-function experiments were performed to determine the effects of Oct4 on HASMC phenotype transition. Chromatin immunoprecipitation, luciferase assay, and rescue experiments were performed to analyze mechanisms of Oct4 on HASMC phenotype transition.

RESULTS

Oct4 expression levels, especially the Oct4A isoform, were significantly higher in TAD patients compared with normal controls. Notably, Oct4 presented a strong and strict nuclear localization in primary HASMCs of TAD patients but a mild and diffuse distribution in both cytoplasm and nucleus in the control group. Overexpression of Oct4 induced dedifferentiation of HASMCs characterized by decreased contractile proteins and elevated migration capability. Krüppel-like factor 5 (KLF5) was found to be a directly regulated target gene of Oct4 in HASMCs. Furthermore, downregulation of KLF5 significantly alleviated the effects of Oct4 on phenotype transition of HASMCs.

CONCLUSIONS

Oct4 expression was significantly upregulated in aortic tissues and primary HASMCs of TAD patients. The increased Oct4 induced phenotype transition of HASMCs from the contractile type to the synthetic type by directly upregulating KLF5.

Surgery for aortic dilatation in patients with bicuspid aortic valves: A statement of clarification from the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Two guidelines from the American College of Cardiology (ACC), the American Heart Association (AHA), and collaborating societies address the risk of aortic dissection in patients with bicuspid aortic valves and severe aortic enlargement: The "2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease" (J Am Coll Cardiol. 2010;55:e27-130) and the "2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease" (J Am Coll Cardiol. 2014;63:e57-185). However, the 2 guidelines differ with regard to the recommended threshold of aortic root or ascending aortic dilatation that would justify surgical intervention in patients with bicuspid aortic valves. The ACC and AHA therefore convened a subcommittee representing members of the 2 guideline writing committees to review the evidence, reach consensus, and draft a statement of clarification for both guidelines. This statement of clarification uses the ACC/AHA revised structure for delineating the Class of Recommendation and Level of Evidence to provide recommendations that replace those contained in Section 9.2.2.1 of the thoracic aortic disease guideline and Section 5.1.3 of the valvular heart disease guideline.

Surgery for Aortic Dilatation in Patients With Bicuspid Aortic Valves: A Statement of Clarification From the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines

Two guidelines from the American College of Cardiology (ACC), the American Heart Association (AHA), and collaborating societies address the risk of aortic dissection in patients with bicuspid aortic valves and severe aortic enlargement: the "2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease" (J Am Coll Cardiol 2010;55:e27-130) and the "2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease" (J Am Coll Cardiol 2014;63:e57-185). However, the 2 guidelines differ with regard to the recommended threshold of aortic root or ascending aortic dilatation that would justify surgical intervention in patients with bicuspid aortic valves. The ACC and AHA therefore convened a subcommittee representing members of the 2 guideline writing committees to review the evidence, reach consensus, and draft a statement of clarification for both guidelines. This statement of clarification uses the ACC/AHA revised structure for delineating the Class of Recommendation and Level of Evidence to provide recommendations that replace those contained in Section 9.2.2.1 of the thoracic aortic disease guideline and Section 5.1.3 of the valvular heart disease guideline.

Impact of thrombospondin-2 gene variations on the risk of thoracic aortic dissection in a Chinese Han population

OBJECTIVE

Genetic factors play an important role in thoracic aortic dissection (TAD) etiology and thrombospondin-2 gene (THBS2) polymorphisms may be involved. This study tried to examine the single-nucleotide polymorphisms (SNP) rs8089 of THBS2 for their association with TAD susceptibility in Chinese Han population.

METHODS

The rs8089 SNP of THBS2 was genotyped in 112 subjects who were diagnosed as TAD and in 184 age- and gender-matched matched controls.

RESULTS

The THBS2 rs8089 SNP was associated with increased TAD susceptibility for allele level comparison (P < 0.0001), and for dominant model (P = 0.0073) or extreme genotype model (P = 0.0459) in Chinese Han Population. But for the recessive model, no statistical difference was found (P = 0.099), which may be resulted from the relatively small sample size and low genotype frequency.

CONCLUSION

In conclusion, the present study suggested that the THBS2 rs8089 variant was associated with TAD, with the G allele representing a risk factor in a Chinese Han population.

Novel findings: Expression of angiotensin-converting enzyme and angiotensin-converting enzyme 2 in thoracic aortic dissection and aneurysm

INTRODUCTION

Angiotensin-converting enzyme (ACE) and ACE2 are key regulators of the renin-angiotensin system, which has been shown to participate in a series of cardiovascular diseases. We hypothesized that dysregulated gene expression of ACE and ACE2 contribute to the formation of thoracic aortic dissection and aneurysm.

MATERIALS AND METHODS

We assessed ACE plasma concentration in 73 patients with acute thoracic aortic dissection (n=34), aneurysm (n=18), coronary heart disease (n=21) and 13 healthy volunteers. ACE and ACE2 gene expression in available aortic tissues was also examined by using quantitative real-time polymerase chain reaction.

RESULTS

In patients with acute aortic dissection, ACE plasma concentration and its mRNA level in aortic tissue were markedly reduced compared with those in patients with aneurysm, coronary heart disease and healthy controls. The level of ACE2 gene expression in dissection samples was also significantly lower than that in aneurysm (8.01±7.44, p<0.01) and coronary heart disease groups (9.61±11.54, p<0.01). A strong correlation was observed between the gene expressions of ACE and those of ACE2, and ACE to ACE2 ratio was significantly elevated in dissection tissues.

CONCLUSIONS

Imbalanced down-regulation of ACE and ACE2 mRNA expression levels may play an important role in the development and progression of thoracic aortic aneurysmal dilatation and subsequently dissection.

Endovascular repair of thoracic aortic aneurysm

A thoracic aortic aneurysm (TAA) is a potentially life-threatening condition with structural weakness of the aortic wall, which can progress to arterial dilatation and rupture. Today, both an increasing awareness of vascular disease and the access to tomographic imaging facilitate the diagnosis of TAA even in an asymptomatic stage. The risk of rupture for untreated aneurysms beyond a diameter of 5.6 cm ranges from 46% to 74% and the two-year mortality rate is greater than 70%, with most deaths resulting from rupture. Treatment options include surgical and non-surgical repair to prevent aneurysm enlargement and rupture. While most cases of ascending aortic involvement are subject to surgical repair (partially with valve-preserving techniques), aneurysm of the distal arch and descending thoracic aorta are amenable to emerging endovascular techniques as an alternative to classic open repair or to a hybrid approach (combining debranching surgery with stent grafting) in an attempt to improve outcomes.

Open repair of descending thoracic aneurysms

INTRODUCTION

Current strategies for operative treatment of a thoracic aortic aneurysm consist of open repair with surgical graft replacement or endovascular exclusion. To reduce mortality and morbidity of open repair, a multimodal approach has gradually evolved by maximizing organ protection.

METHODS

On a total of 1108 patients treated in our Center from 1993 for pathology involving the thoracic aorta, we reviewed the prospectively collected data of 194 consecutive patients who underwent open thoracic aortic aneurysm repair, 104 (54%) for degenerative aneurysms, 65 (34%) for dissections, 25 (12%) for other pattern of disease. Left Heart Bypass was used in 82% of cases, clamp and sew technique in 16%, hypotermic circulatory arrest in 2%.

RESULTS

Overall perioperative mortality was 4.1%. The rate of pulmonary complications was 8.8%. The rate of cardiac complications, i.e. new onset myocardial necrosis demonstrated by positive blood tests, was 6.2%. The rate of renal complications was 7.2%. Cerebrovascular accident, defined as a new neurologic deficit lasting more than 24 hours confirmed by imaging, occurred in 2.0% of patients. The rate of spinal cord ischemia, manifesting either as paraplegia or paraparesis, was 4.6%.

CONCLUSIONS

Mortality and morbidity rates of open thoracic aortic aneurysm repair are currently satisfactory especially in fit patients. In order to define surgical indications and the role of endovascular repair, consideration of age of the patient, comorbidity, symptoms, life expectancy, likely quality of life (if asymptomatic), aortic diameter, aneurysm morphology, aneurysm extent, suitability of landing zones, and operator experience are all distinctly relevant.