Explore the vast range of titles available.

Sporadic aortic aneurysm and dissections (AADs) are common vascular diseases that carry a high mortality rate. ADAMTS-4 (a disintegrin-like and metalloproteinase with thrombospondin motifs-4) is a secreted proteinase involved in inflammation and matrix degradation. We previously showed ADAMTS-4 levels were increased in human sporadic descending thoracic AAD (TAAD) samples. Here, we provide evidence that ADAMTS-4 contributes to aortic destruction and sporadic AAD development. In a mouse model of sporadic AAD induced by a high-fat diet and angiotensin II infusion, ADAMTS-4 deficiency ( Adamts-4−/− ) significantly reduced challenge-induced aortic diameter enlargement, aneurysm formation, dissection and aortic rupture. Aortas in Adamts-4−/− mice showed reduced elastic fibre destruction, versican degradation, macrophage infiltration, and apoptosis. Interestingly, ADAMTS-4 was directly involved in smooth muscle cell (SMC) apoptosis. Under stress, ADAMTS-4 translocated to the nucleus in SMCs, especially in apoptotic SMCs. ADAMTS-4 directly cleaved and degraded poly ADP ribose polymerase-1 (a key molecule in DNA repair and cell survival), leading to SMC apoptosis. Finally, we showed significant ADAMTS-4 expression in aortic tissues from patients with sporadic ascending TAAD, particularly in SMCs. Our findings indicate that ADAMTS-4 induces SMC apoptosis, degrades versican, promotes inflammatory cell infiltration, and thus contributes to sporadic AAD development.

Activation of the AMPK-FOXO3 Pathway Reduces Fatty Acid–Induced Increase in Intracellular Reactive Oxygen Species by Upregulating Thioredoxin Xiao-Nan Li 1 , 2 , 3 , Jun Song 1 , 2 , 3 , Lin Zhang 1 , 2 , Scott A. LeMaire 1 , 2 , Xiaoyang Hou 1 , 2 , 3 , Cheng Zhang 1 , 2 , 3 , Joseph S. Coselli 1 , 2 , Li Chen 3 , Xing Li Wang 1 , 2 , Yun Zhang 3 and Ying H. Shen 1 , 2 1 Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas; 2 Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas; 3 Qilu Hospital, Shandong University, Jinan, Shandong, China. Corresponding authors: Yun Zhang, zhangyun{at}sdu.edu.cn , and Ying H. Shen, hyshen{at}bcm.edu . X.-N.L. and J.S. contributed equally to this study. Abstract OBJECTIVE Oxidative stress induced by free fatty acids contributes to the development of cardiovascular diseases in patients with metabolic syndrome. Reducing oxidative stress may attenuate these pathogenic processes. Activation of AMP-activated protein kinase (AMPK) has been reported to reduce intracellular reactive oxygen species (ROS) levels. The thioredoxin (Trx) system is a major antioxidant system. In this study, we investigated the mechanisms involved in the AMPK-mediated regulation of Trx expression and the reduction of intracellular ROS levels. RESEARCH DESIGN AND METHODS We observed that activation of AMPK by 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) significantly reduced ROS levels induced by palmitic acid in human aortic endothelial cells. Activation of AMPK increased expression of the antioxidant Trx, which mediated the ROS reduction. RT-PCR showed that AMPK regulated Trx at the transcriptional level. RESULTS Forkhead transcription factor 3 (FOXO3) was identified as the target transcription factor involved in the upregulation of Trx expression. FOXO3 bound to the Trx promoter, recruited the histone acetylase p300 to the Trx promoter, and formed a transcription activator complex, which was enhanced by AICAR treatment. AMPK activated FOXO3 by promoting its nuclear translocation. We further showed that AICAR injection increased the expression of Trx and decreased ROS production in the aortic wall of ApoE−/− mice fed a high-fat diet. CONCLUSIONS These results suggest that activation of the AMPK-FOXO3 pathway reduces ROS levels by inducing Trx expression. Thus, the AMPK-FOXO3-Trx axis may be an important defense mechanism against excessive ROS production induced by metabolic stress and could be a therapeutic target in treating cardiovascular diseases in metabolic syndrome. Footnotes The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Received October 31, 2008. Accepted June 28, 2009. © 2009 by the American Diabetes Association.

Reoperative thoracoabdominal aortic aneurysm repair is frequently necessary and brings with it a unique set of challenges. Typically, most reoperative repairs are necessitated by aortic disease progressing into previously healthy aortic tissue from a replaced section of the aorta (an extension of the previous repair) or, to a lesser degree, because of a late complication of prior distal aortic repair (an open or endovascular repair failure). Characterizing the reason for the reoperation as well as the location of prior repair is the first step towards anticipating major outcomes following such repair. Since the introduction of endovascular repair for aortic aneurysms, indications for open repair have become more specific and limited; many centers have justified using endovascular approaches in patients with prior open aortic repair by deeming these patients “high risk” because of their previous incision. Our analysis found that reoperative repairs were not typically subject to worse early outcomes than patients without prior distal aortic repair, except for the more complicated types of reoperation, which involve infection.

Dianna Milewicz and colleagues report a genome-wide association study of sporadic thoracic aortic aneurysm and dissection. They identify an associated locus on 15q21 spanning the FBN1 gene. Although thoracic aortic aneurysms and dissections (TAAD) can be inherited as a single-gene disorder, the genetic predisposition in the majority of affected people is poorly understood. In a multistage genome-wide association study (GWAS), we compared 765 individuals who had sporadic TAAD (STAAD) with 874 controls and identified common SNPs at a 15q21.1 locus that were associated with STAAD, with odds ratios of 1.6–1.8 that achieved genome-wide significance. We followed up 107 SNPs associated with STAAD with P < 1 × 10 −5 in the region, in two separate STAAD cohorts. The associated SNPs fall into a large region of linkage disequilibrium encompassing FBN1 , which encodes fibrillin-1. FBN1 mutations cause Marfan syndrome, whose major cardiovascular complication is TAAD. This study shows that common genetic variants at 15q21.1 that probably act via FBN1 are associated with STAAD, suggesting a common pathogenesis of aortic disease in Marfan syndrome and STAAD.

Short- and long-term mortality in women who undergo coronary artery bypass grafting (CABG) has been evaluated in multiple studies with conflicting results. The investigators conducted a meta-analysis of all existing studies to evaluate the impact of female gender on mortality in patients who undergo isolated CABG. A comprehensive search of studies published through May 31, 2012 identified 20 studies comparing men and women who underwent isolated CABG. All-cause mortality was evaluated at short-term (postoperative period and/or at 30 days), midterm (1-year), and long-term (5-year) follow-up. Odds ratios (ORs) and 95% confidence interval (CIs) were calculated using a random-effects model. A total of 966,492 patients (688,709 men [71%], 277,783 women [29%]) were included in this meta-analysis. Women were more likely to be older; had significantly greater co-morbidities, including hypertension, diabetes mellitus, hyperlipidemia, unstable angina, congestive heart failure, and peripheral vascular disease; and were more likely to undergo urgent CABG (51% vs 44%, p <0.01). Short-term mortality (OR 1.77, 95% CI 1.67 to 1.88) was significantly higher in women. At midterm and long-term follow-up, mortality remained high in women compared with men. Women remained at increased risk for short-term mortality in 2 subgroup analyses including prospective studies (n = 41,500, OR 1.83, 95% CI 1.59 to 2.12) and propensity score–matched studies (n = 11,522, OR 1.36, 95% CI 1.04 to 1.78). In conclusion, women who underwent isolated CABG experienced higher mortality at short-term, midterm, and long-term follow-up compared with men. Mortality remained independently associated with female gender despite propensity score–matched analysis of outcomes.

Chromosomal deletions or reciprocal duplications of the 16p13.1 region have been implicated in a variety of neuropsychiatric disorders such as autism, schizophrenia, epilepsies, and attention-deficit hyperactivity disorder (ADHD). In this study, we investigated the association of recurrent genomic copy number variants (CNVs) with thoracic aortic aneurysms and dissections (TAAD). By using SNP arrays to screen and comparative genomic hybridization microarrays to validate, we identified 16p13.1 duplications in 8 out of 765 patients of European descent with adult-onset TAAD compared with 4 of 4,569 controls matched for ethnicity (P = 5.0 × 10⁻⁵, OR = 12.2). The findings were replicated in an independent cohort of 467 patients of European descent with TAAD (P = 0.005, OR = 14.7). Patients with 16p13.1 duplications were more likely to harbor a second rare CNV (P = 0.012) and to present with aortic dissections (P = 0.010) than patients without duplications. Duplications of 16p13.1 were identified in 2 of 130 patients with familial TAAD, but the duplications did not segregate with TAAD in the families. MYH11, a gene known to predispose to TAAD, lies in the duplicated region of 16p13.1, and increased MYH11 expression was found in aortic tissues from TAAD patients with 16p13.1 duplications compared with control aortas. These data suggest chromosome 16p13.1 duplications confer a risk for TAAD in addition to the established risk for neuropsychiatric disorders. It also indicates that recurrent CNVs may predispose to disorders involving more than one organ system, an observation critical to the understanding of the role of recurrent CNVs in human disease and a finding that may be common to other recurrent CNVs involving multiple genes.

The extent to which patients with an abdominal aortic aneurysm (AAA) should exercise remains unclear, given theoretical concerns over the perceived risk of blood pressure‐induced rupture, which is often catastrophic. This is especially pertinent during cardiopulmonary exercise testing, when patients are required to perform incremental exercise to symptom‐limited exhaustion for the determination of cardiorespiratory fitness. This multimodal metric is being used increasingly as a complementary diagnostic tool to inform risk stratification and subsequent management of patients undergoing AAA surgery. In this review, we bring together a multidisciplinary group of physiologists, exercise scientists, anaesthetists, radiologists and surgeons to challenge the enduring ‘myth’ that AAA patients should be fearful of and avoid rigorous exercise. On the contrary, by appraising fundamental vascular mechanobiological forces associated with exercise, in conjunction with ‘methodological’ recommendations for risk mitigation specific to this patient population, we highlight that the benefits conferred by cardiopulmonary exercise testing and exercise training across the continuum of intensity far outweigh the short‐term risks posed by potential AAA rupture.

In the last decade, thoracic endovascular aortic aneurysm repair (TEVAR) has emerged as an appealing alternative to the traditional open aortic aneurysm repair. This is largely due to generally improved early outcomes associated with TEVAR, including lower perioperative mortality and morbidity. However, it is relatively common for patients who undergo TEVAR to need a secondary intervention. In select circumstances, these secondary interventions are performed as an open procedure. Although it is difficult to assess the rate of open repairs after TEVAR, the rates in large series of TEVAR cases (>300) have ranged from 0.4 to 7.9 %. Major complications of TEVAR that typically necessitates open distal aortic repair (i.e., repair of the descending thoracic or thoracoabdominal aorta) include endoleak (especially type I), aortic fistula, endograft infection, device collapse or migration, and continued expansion of the aneurysm sac. Conversion to open repair of the distal aorta may be either elective (as for many endoleaks) or emergent (as for rupture, retrograde complicated dissection, malperfusion, and endograft infection). In addition, in select patients (e.g., those with a chronic aortic dissection), unrepaired sections of the aorta may progressively dilate, resulting in the need for multiple distal aortic repairs. Open repairs after TEVAR can be broadly classified as full extraction, partial extraction, or full salvage of the stent-graft. Although full and partial stent-graft extraction imply failure of TEVAR, such failure is generally absent in cases where the stent-graft can be fully salvaged. We review the literature regarding open repair after TEVAR and highlight operative strategies.

“Academic surgeon” describes a member of a medical school department of surgery, but this term does not fully define the important role of such physician-scientists in advancing surgical science through translational research and innovation. The curriculum vitae and self-descriptive vignettes of the records of achievement of seven surgeons possessing documented records of academic leadership, innovation, and dissemination of knowledge were reviewed. Out analysis yielded seven attributes of the archetypal academic surgeon: 1) identifies complex clinical problems ignored or thought unsolvable by others, 2) becomes an expert, 3) innovates to advance treatment, 4) observes outcomes to further improve and innovate, 5) disseminates knowledge and expertise, 6) asks important questions to further improve care, and 7) trains the next generation of surgeons and scientists. Although alternative pathways to innovation and academic contribution also exist, the academic surgeon typically devotes years of careful observation, analysis, and iterative investigation to identify and solve challenging or unexplored clinical problems, ideally leverages resources available in academic medical centers to support these endeavors.

Free Fatty Acids Inhibit Insulin Signaling–Stimulated Endothelial Nitric Oxide Synthase Activation Through Upregulating PTEN or Inhibiting Akt Kinase Xing Li Wang , Lin Zhang , Keith Youker , Ming-Xiang Zhang , Jian Wang , Scott A. LeMaire , Joseph S. Coselli and Ying H. Shen From the Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas Address correspondence and reprint requests to Dr. Ying. H. Shen MS NAB 2010, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030. E-mail: hyshen{at}bcm.edu ; or Dr. Xing Li Wang, MS NAB 2010, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030. E-mail: xlwang{at}bcm.edu Abstract In metabolic syndrome, a systemic deregulation of the insulin pathway leads to a combined deregulation of insulin-regulated metabolism and cardiovascular functions. Free fatty acids (FFAs), which are increased in metabolic syndrome, inhibit insulin signaling and induce metabolic insulin resistance. This study was designed to examine FFAs’ effects on vascular insulin signaling and endothelial nitric oxide (NO) synthase (eNOS) activation in endothelial cells. We showed that FFAs inhibited insulin signaling and eNOS activation through different mechanisms. While linoleic acid inhibited Akt-mediated eNOS phosphorylation, palmitic acid appeared to affect the upstream signaling. Upregulation of PTEN (phosphatase and tensin homolog deleted on chromosome 10) activity and transcription by palmitic acid mediated the inhibitory effects on insulin signaling. We further found that activated stress signaling p38, but not Jun NH 2 -terminal kinase, was involved in PTEN upregulation. The p38 target transcriptional factor activating transcription factor (ATF)-2 bound to the PTEN promoter, which was increased by palmitic acid treatment. In summary, both palmitic acid and linoleic acid exert inhibitory effect on insulin signaling and eNOS activation in endothelial cells. Palmitic acid inhibits insulin signaling by promoting PTEN activity and its transcription through p38 and its downstream transcription factor ATF-2. Our findings suggest that FFA-mediated inhibition of vascular insulin signaling and eNOS activation may contribute to cardiovascular diseases in metabolic syndrome. ATF, activating transcription factor CREBP, cAMP-responsive element–binding protein EBM, endothelial cell basic medium eNOS, endothelial nitric oxide synthase FFA, free fatty acid HAEC, human aortic endothelial cell JNK, Jun NH2-terminal kinase PDK, phosphoinositide-dependent kinase PI, phosphatidylinositol PIP3, phosphatidylinositol-3.4,5-triphosphate Footnotes The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Accepted May 22, 2006. Received December 5, 2005. DIABETES