Type A Aortic Dissection in Patients With Bicuspid Aortic Valve Aortopathy.

BACKGROUND: The aim of this study was to evaluate clinical, aortic, and outcome characteristics of type A aortic dissection patients with bicuspid aortic valves (BAVs) and tricuspid aortic valves (TAVs). METHODS: Patient characteristics and radiographic, operative, and outcome data were evaluated and compared between 1068 TAV patients and 72 BAV patients operated on for type A aortic dissection in 2 centers. Predissection aortic diameters were calculated as previously reported for TAV patients. RESULTS: BAV patients were significantly younger (P < .001) and had a lower incidence of cardiovascular risk factors. Although the clinical presentation was similar, the dissection affected the abdominal aorta significantly more often in TAV patients (P = .029). Aortic root replacements were performed significantly more often in BAV patients (P < .001). Postoperative outcome was similar between the 2 groups. BAV patients had a significantly larger maximum postdissection diameter (P < .001) and calculated predissection diameter (P < .001) compared with TAV patients. Predissection ascending aortic diameters were less than 5.5 cm in 96% of all TAV patients and less than 5.0 cm in 76% of all BAV patients. CONCLUSIONS: Acute type A aortic dissection in BAV patients is not associated with worse clinical or long-term outcome but significantly influences the proximal aortic repair. After modeling predissection aortic diameters, less than 5% of all TAV patients and possibly less than 25% of all BAV patients would meet the elective threshold for preventative replacement of the ascending aorta.

Outcome after aortic, axillary, or femoral cannulation for acute type A aortic dissection.

OBJECTIVE: The optimal method for arterial cannulation in acute aortic dissection type A (ADA) remains controversial. The aim of this study was to compare central ascending aortic, axillary, and femoral cannulation in patients who underwent surgery for acute ADA. METHODS: Between 2006 and 2017, 584 patients were operated on for acute ADA. Of those, 355 (61%) underwent ascending aortic, 101 (17%) right axillary, and 128 (22%) femoral cannulation for arterial inflow. Clinical features and outcomes were compared after inverse probability weighting. RESULTS: After inverse probability weighting there were no statistical differences in preoperative characteristics. Operative details differed significantly among the 3 groups: hemiarch replacement was performed more often in the central aortic and the femoral group (P < .001), whereas total arch replacement was performed more often in the axillary group (P < .001). Cardiopulmonary bypass (P = .022) and aortic cross-clamp (P = .021) times were shortest in the aortic cannulation group and longest in the femoral cannulation group. Postoperative morbidities were similar; procedure-related stroke (P = .783) and the need for renal replacement therapy (P = .446). In-hospital mortality (P = .680) and long-term survival were similar (log rank, P = .704). Multilevel multivariate mixed effect logistic regression showed that the cannulation strategy was not associated with in-hospital mortality. CONCLUSIONS: Central ascending aortic cannulation in patients with ADA can be used as safely as axillary or femoral cannulation, providing another option for quick and easy establishment of cardiopulmonary bypass.

Influence of Age and the Burden of Ischemic Injury on the Outcome of Type A Aortic Dissection Repair.

BACKGROUND: This study evaluated operative details and postoperative outcomes in elderly patients according to the burden of ischemic injury. METHODS: Between 2002 and 2017, 1187 patients in 2 centers were operated on for aortic dissection type A (ADA). Patients were grouped according to the Penn classification: class A, 628 patients; class B, 196; class C, 224; and class BC, 139. The perioperative conditions and outcomes were analyzed. RESULTS: The likelihood of presenting in a Penn class changed significantly with age (P = .02). Also, the probability of ADA extension into the supraaortic vessels (P < .001) or the distal aorta (P < .001) decreased significantly over age. Nevertheless, there was no significant difference in the distal aortic repair between younger and older patients. The probability of in-hospital mortality increased significantly in all Penn classes with age (P < .001). Yet, predicted mortality remained below 15% for any age in class A patients but increased up to 25% in class B and C patients and beyond 50% in class BC patients. Class A or B were not predictive of in-hospital mortality in septuagenarians or octogenarians. CONCLUSIONS: Age by itself is not a rational criterion to select patients for surgical treatment, and a surgical approach is very reasonable in all class A patients independent of age. The predicted mortality in classes B, C, and particularly class BC is dismal in the elderly. Those patients may benefit from alternative, evolving therapeutic options such as ascending endovascular treatments.

Management of Patients With Coronary Artery Malperfusion Secondary to Type A Aortic Dissection.

BACKGROUND: This study reviewed our experience with coronary artery (CA) malperfusion secondary to type A aortic dissection. METHODS: Between 2002 and 2017, 76 patients presented with CA malperfusion, with a dissection flap limited to the aorta in the region of the coronary ostium (type A lesion) in 26 (34%), with a dissection flap involving the CA itself (type B lesion) in 32 (42%), or with complete avulsion of the CA (type C lesion) in 18 (24%). RESULTS: Ostial repair was successfully performed in 23 type A patients (88%), in 20 type B patients (63%), and in no type C patient (0%). CA bypass grafting was performed when antegrade cardioplegia could not be applied in all 18 type C patients (100%) and in 5 type B patients (16%) because of a primary entry at the coronary ostium and in 7 patients (type A: 3 patients [12%], type B: 4 patients [13%]) with evidence of CA disease (p < 0.001). Perioperative mortality in patients with CA malperfusion was high (18 patients [24%]), but there was no difference in short-term (p = 0.153) or long-term survival (log-rank p = 0.542). Also, a landmark analysis showed equal survival of discharged patients with and without CA malperfusion (log-rank p = 0.645). CONCLUSIONS: We recommend CA bypass grafting in patients with type C lesions or in patients with underlying CA disease for optimal delivery of cardioplegia and ostial pledgetted suture repair in patients with type A lesions or type B lesions when the administration of antegrade cardioplegia is successful.

Porphyrin-Based SOD Mimic MnTnBu OE -2-PyP5+ Inhibits Mechanisms of Aortic Valve Remodeling in Human and Murine Models of Aortic Valve Sclerosis.

Background Aortic valve sclerosis ( AVS c), the early asymptomatic presentation of calcific aortic valve (AV) disease, affects 25% to 30% of patients aged >65 years. In vitro and ex vivo experiments with antioxidant strategies and antagonists of osteogenic differentiation revealed that AVS c is reversible. In this study, we characterized the underlying changes in the extracellular matrix architecture and valve interstitial cell activation in AVSc and tested in vitro and in vivo the activity of a clinically approved SOD (superoxide dismutase) mimic and redox-active drug MnTnBu OE -2-PyP5+ ( BMX -001). Methods and Results After receiving informed consent, samples from patients with AVS c, AV stenosis, and controls were collected. Uniaxial mechanical stimulation and in vitro studies on human valve interstitial cells were performed. An angiotensin II chronic infusion model was used to impose AV thickening and remodeling. We characterized extracellular matrix structures by small-angle light scattering, scanning electron microscopy, histology, and mass spectrometry. Diseased human valves showed altered collagen fiber alignment and ultrastructural changes in AVS c, accumulation of oxidized cross-linking products in AV stenosis, and reversible expression of extracellular matrix regulators ex vivo. We demonstrated that MnTnBu OE -2-PyP5+ inhibits human valve interstitial cell activation and extracellular matrix remodeling in a murine model (C57 BL /6J) of AVS c by electron microscopy and histology. Conclusions AVS c is associated with architectural remodeling despite marginal effects on the mechanical properties in both human and mice. MnTnBu OE -2-PyP5+ controls AV thickening in a murine model of AVS c. Because this compound has been approved recently for clinical use, this work could shift the focus for the treatment of calcific AV disease, moving from AV stenosis to an earlier presentation ( AVS c) that could be more responsive to medical therapies.

Outcome After Operation for Aortic Dissection Type A in Morbidly Obese Patients.

BACKGROUND: The number of obese patients is increasing, and more obese patients are likely to present for surgical repair of aortic dissection type A (ADA). We evaluated the effect of this procedure on the postoperative outcome of patients based on their body mass index (BMI; calculated as kg/m2). METHODS: A total of 667 patients who underwent surgical repair of ADA between 2003 and 2017 were retrospectively analyzed. Patients were divided into four groups according to BMI: normal weight (BMI: 18 to <25, n = 186), overweight (BMI: 25 to <30, n = 238), obese (BMI: 30 to <35, n = 144), and morbidly obese (BMI ≥35, n = 99). We compared clinical features and outcomes. RESULTS: No statistical difference was found regarding clinical presentation or proximal or distal aortic repair. Postoperative complications were similar among all groups. Although the rate for reintubation, tracheotomy, and the length of stay in the intensive care unit tended to be similar, the time to extubation (p = 0.010) and the total length of hospital stay (p = 0.017) were significantly longer in morbidly obese patients. Significantly more blood was transfused and replaced in the normal weight patients compared with the obese patients: in median 69% of the calculated blood volume was replaced in the normal weight patients compared with 32% in the morbidly obese patients (p < 0.001). In-hospital mortality and late survival were similar among all weight groups. CONCLUSIONS: Despite the comorbidities that are associated with obesity, obese patients undergoing surgical repair of ADA are not at greater risk of death or other adverse outcomes. An immediate surgical approach should be considered in all patients independent of weight.

Serotonin receptor 2B signaling with interstitial cell activation and leaflet remodeling in degenerative mitral regurgitation.

AIMS: Mitral valve interstitial cells (MVIC) play an important role in the pathogenesis of degenerative mitral regurgitation (MR) due to mitral valve prolapse (MVP). Numerous clinical studies have observed serotonin (5HT) dysregulation in cardiac valvulopathies; however, the impact of 5HT-mediated signaling on MVIC activation and leaflet remodeling in MVP have been investigated to a limited extent. Here we test the hypothesis that 5HT receptors (5HTRs) signaling contributes to MVP pathophysiology. METHODS AND RESULTS: Diseased human MV leaflets were obtained during cardiac surgery for MVP; normal MV leaflets were obtained from heart transplants. MV RNA was used for microarray analysis of MVP patients versus control, highlighting genes that indicate the involvement of 5HTR pathways and extracellular matrix remodeling in MVP. Human MV leaflets were also studied in vitro and ex vivo with biomechanical testing to assess remodeling in the presence of a 5HTR2B antagonist (LY272015). MVP leaflets from Cavalier King Charles Spaniels were used as a naturally acquired in vivo model of MVP. These canine MVP leaflets (N=5/group) showed 5HTR2B upregulation. This study also utilized CB57.1ML/6 mice in order to determine the effect of Angiotensin II infusion on MV remodeling. Histological analysis showed that MV thickening due to chronic Angiotensin II remodeling is mitigated by a 5HTR2B antagonist (LY272015) but not by 5HTR2A inhibitors. CONCLUSION: In humans, MVP is associated with an upregulation in 5HTR2B expression and increased 5HT receptor signaling in the leaflets. Antagonism of 5HTR2B mitigates MVIC activation in vitro and MV remodeling in vivo. These observations support the view that 5HTR signaling is involved not only in previously reported 5HT-related valvulopathies, but it is also involved in the pathological remodeling of MVP.

Mitral valve endothelial cells secrete osteoprotegerin during endothelial mesenchymal transition.

AIMS: Mitral valve prolapse (MVP) has a prevalence of 3% in the general population, affecting >176 million people worldwide. Despite this, little is known about the molecular and cellular mechanisms involved in the progression of MVP and surgical intervention is the only available option. In this study we investigated the role of osteoprotegerin (OPG) during endothelial to mesenchymal transition (EndMT) in MVP. METHODS AND RESULTS: VECs and VICs were isolated from posterior mitral valve leaflets of patients undergoing mitral valve repair (n=25). Plasma was collected from 57 subjects (29 controls and 28 MVP patients). Overexpression of OPG during EndMT followed by autocrine effects characterised by reactive oxygen species increment and accelerated migration was documented. In addition, OPG increased VIC proliferation. Finally, OPG plasma levels were significantly higher in MVP patients compared to control subjects and the area under the ROC curve was 0.92. CONCLUSION: EndMT has been recognised as a possible pathological mechanism for MVP. For the first time, we report the involvement of OPG in cellular and molecular changes in MVP isolated cells. In addition, we detected elevated circulating OPG levels in MVP patients when compared to controls, which supports the hypothesis that OPG is involved in MVP development and progression.

Matrix metalloproteinase-12 is an essential mediator of acute and chronic arterial stiffening.

Arterial stiffening is a hallmark of aging and risk factor for cardiovascular disease, yet its regulation is poorly understood. Here we use mouse modeling to show that matrix metalloproteinase-12 (MMP12), a potent elastase, is essential for acute and chronic arterial stiffening. MMP12 was induced in arterial smooth muscle cells (SMCs) after acute vascular injury. As determined by genome-wide analysis, the magnitude of its gene induction exceeded that of all other MMPs as well as those of the fibrillar collagens and lysyl oxidases, other common regulators of tissue stiffness. A preferential induction of SMC MMP12, without comparable effect on collagen abundance or structure, was also seen during chronic arterial stiffening with age. In both settings, deletion of MMP12 reduced elastin degradation and blocked arterial stiffening as assessed by atomic force microscopy and immunostaining for stiffness-regulated molecular markers. Isolated MMP12-null SMCs sense extracellular stiffness normally, indicating that MMP12 causes arterial stiffening by remodeling the SMC microenvironment rather than affecting the mechanoresponsiveness of the cells themselves. In human aortic samples, MMP12 levels strongly correlate with markers of SMC stiffness. We conclude that MMP12 causes arterial stiffening in mice and suggest that it functions similarly in humans.

Outcomes of surgery for chronic type A aortic dissection.

BACKGROUND: Data on outcomes of surgery for chronic Stanford type A aortic dissection are limited. We investigated the primary surgery and long-term results in patients with chronic dissection of the native ascending aorta. METHODS: Between 1993 and 2013, among 696 patients (median age, 61 years [first quartile, 50; third quartile 73 years]; 64% males) who underwent surgery for type A dissection, 67 (10%) had chronic dissection by traditional criteria (>14 days). Median follow-up was 4.1 years (first quartile, 1.9; third quartile, 7.3 years; 3,105 patient-years). RESULTS: Patients with chronic dissection more frequently had undergone previous cardiac surgery (37% versus 9%; p < 0.001) and more frequently had bicuspid aortic valve syndrome (19% versus 7%; p < 0.001) and larger ascending aortic diameter (6.0 cm [first quartile 5.2; third quartile 7.2 cm] versus 4.9 cm [first quartile, 4.5; third quartile, 5.7 cm]; p < 0.001). Aortic dissection extended beyond the aortic arch less frequently in chronic dissection patients (27% versus 70%; p < 0.001). Moderate to severe aortic insufficiency rate was higher in chronic group (65% versus 36%; p < 0.001); they required aortic root replacement more frequently (42% versus 18%; p < 0.001) and had lower in-hospital mortality (4.5% versus 13.2%; p = 0.062). Resection of all dissected aortic tissue was achieved in 73% chronic and 30% acute dissection patients. Overall survival was better in the chronic group with 80% ± 5% versus 68% ± 2% at 5 years and 64% ± 13% versus 49% ± 3% at 10 years (log rank p = 0.021). CONCLUSIONS: Patients with chronic and acute type A dissection differ substantially in presentation, management, and outcome. Replacement of all dissected aortic tissue can be performed safely in the majority of patients with chronic type A dissection.

Circulating soluble receptor for advanced glycation end product identifies patients with bicuspid aortic valve and associated aortopathies.

OBJECTIVE: A total of 30% to 50% of patients with bicuspid aortic valve (BAV) require surgery for aortic valve replacement (AVR), ascending aortic replacement (AA), or both. To prevent adverse aortic events, they are risk stratified using imperfect criteria based on imaging modalities. As a result, a significant number of dissections occur outside of the parameters suggested by the guidelines. Advanced glycation end products (AGEs) are associated with valve and vascular remodeling and trigger the release of a soluble receptor (soluble receptor for advanced glycation end product [sRAGE]). This study aims to characterize sRAGE as a diagnostic and risk-stratification tool for patients with BAV referred for surgery. APPROACH AND RESULTS: sRAGE was measured in 135 patients (BAV, n=74; tricuspid aortic valve, n=61) meeting inclusion criteria from 338 enrolled patients undergoing AVR and AA. Univariate and multivariate analyses were performed. sRAGE level was significantly associated with the presence of BAV, independent of age, sex, and common risk factors for vascular disease (P<0.001). Within the BAV cohort, patients referred for AA and AVR had higher sRAGE values than patients undergoing AVR only (P=0.002). Patients with BAV <60 years of age, presenting with both valve and aortic diseases (fast progressors), had higher sRAGE than older patients who only needed AVR (slow progressors). Histological analysis showed that sRAGE correlates with dysfunctional aortic microstructure and does not correlate with aortic diameter (R(2)=0.007; P=0.51) or diameter/body surface area (R(2)=0.011; P=0.42). CONCLUSIONS: These results show that elevated level of circulating sRAGE is associated with the presence of BAV and associated aortopathies, independent of aortic diameter.

Osteopontin-CD44v6 interaction mediates calcium deposition via phospho-Akt in valve interstitial cells from patients with noncalcified aortic valve sclerosis.

OBJECTIVE: The activation of valve interstitial cells (VICs) toward an osteogenic phenotype characterizes aortic valve sclerosis, the early asymptomatic phase of calcific aortic valve disease. Osteopontin is a phosphorylated acidic glycoprotein that accumulates within the aortic leaflets and labels VIC activation even in noncalcified asymptomatic patients. Despite this, osteopontin protects VICs against in vitro calcification. Here, we hypothesize that the specific interaction of osteopontin with CD44v6, and the related intracellular pathway, prevents calcium deposition in human-derived VICs from patients with aortic valve sclerosis. APPROACH AND RESULTS: On informed consent, 23 patients and 4 controls were enrolled through the cardiac surgery and heart transplant programs. Human aortic valves and VICs were tested for osteogenic transdifferentiation, ex vivo and in vitro. Osteopontin-CD44 interaction was analyzed using proximity ligation assay and the signaling pathways investigated. A murine model based on angiotensin II infusion was used to mimic early pathological remodeling of the aortic valves. We report osteopontin-CD44 functional interaction as a hallmark of early stages of calcific aortic valve disease. We demonstrated that osteopontin-CD44 interaction mediates calcium deposition via phospho-Akt in VICs from patients with noncalcified aortic valve sclerosis. Finally, microdissection analysis of murine valves shows increased cusp thickness in angiotensin II-treated mice versus saline infused along with colocalization of osteopontin and CD44 as seen in human lesions. CONCLUSIONS: Here, we unveil a specific protein-protein association and intracellular signaling mechanisms of osteopontin. Understanding the molecular mechanisms of early VIC activation and calcium deposition in asymptomatic stage of calcific aortic valve disease could open new prospective for diagnosis and therapeutic intervention.

Modeling of predissection aortic size in acute type A dissection: More than 90% fail to meet the guidelines for elective ascending replacement.

OBJECTIVES: The current guidelines for ascending aortic replacement were determined from already dissected aorta diameters. Previous computed tomography-based work on humans who underwent imaging before and directly after aortic dissection onset has shown an average 30% increase in the ascending aortic diameter with acute dissection. The present investigation evaluated the incidence of predissection ascending aortic dilatation in acute type A dissection. METHODS: From 2002 to 2013, 495 patients presented with acute type A aortic dissection to 1 center. Of these cases, 343 were non-Marfan, nonbicuspid with spontaneous dissection etiology. In those with available preoperative computed tomography angiograms (n = 83) or transesophageal echocardiograms (n = 260), the predissection ascending aorta diameters were modeled from the dissected aorta diameters by subtraction of the average diameter increase rate. RESULTS: Altogether 343 patients were included (age, 62 years; range, 53-73; 64% men). The median modeled predissection ascending diameter was 3.7 cm (first quartile, 3.3; third quartile, -4.1). Of the 343 patients, 334 (97%) and 315 (92%) had an ascending diameter before dissection onset of <5.5 cm and <5.0 cm, respectively. More than 60% of women and 70% of men had a nondilated ascending aorta before type A dissection onset. The median predissection ascending aortic diameter did not differ between women and men (3.7 cm; first quartile, 3.4; third quartile, 4.2; vs 3.7 cm; first quartile, 3.3; third quartile, 4.1; P = .810). CONCLUSIONS: More than 60% of patients with spontaneous, non-Marfan, nonbicuspid, type A dissection will have a nondilated ascending aorta before dissection onset. Only 3% would meet the criteria for elective ascending replacement to prevent aortic dissection. Additional research on the genetic and biochemical predictors of aortic dissection is essential.

Development of a single endovascular device for aortic valve replacement and ascending aortic repair.

BACKGROUND AND AIM OF THE STUDY: Transcatheter aortic valve implantation (TAVI) is contraindicated in the presence of an ascending aortic aneurysm. Our aim was to design a composite endovascular device enabling ascending aortic repair and TAVI. METHODS: From 2007 to 2013, among 1196 patients with severe aortic stenosis screened for TAVI, 79 nonbicuspid patients had ascending aortic diameter >45 mm. Proximal aortic geometry was assessed in those with computed tomography angiography. RESULTS: All together, 51 patients (35 males, aged 85 ± 8 years; 19 TAVI, 10 open Wheat procedures, 22 managed conservatively) were included. The required annular diameter for implantation of currently available TAVI prostheses was met in 41% (21/51). Novel prosthetic valves appropriate for annular range up to 30 mm would extend device applicability to 78% (40/51). Proximal and distal diameters of the graft-covering portion ranging between 30 and 46 mm would enable 10% graft oversizing in all but six patients. In 88% (45/51) the required minimum 10 mm distance between aortic valve annulus and coronary artery ostia was found. Mean distance between left and right coronary artery ostia and sinotubular junction was 2.6 ± 1.5 and 3.2 ± 1.7 mm, respectively. CONCLUSIONS: Novel composite endovascular valved grafts may extend the application of transcatheter techniques to patients denied TAVI due to a concomitant ascending aneurysm. The location of coronary arteries in relation to the sinotubular junction must be addressed in designing these composite valve grafts.

Type A aortic dissection in Marfan syndrome: extent of initial surgery determines long-term outcome.

BACKGROUND: Data on outcomes after Stanford type A aortic dissection in patients with Marfan syndrome are limited. We investigated the primary surgery and long-term results in patients with Marfan syndrome who suffered aortic dissection. METHODS AND RESULTS: Among 1324 consecutive patients with aortic dissection type A, 74 with Marfan syndrome (58% men; median age, 37 years [first and third quartiles, 29 and 48 years]) underwent surgical repair (85% acute dissections; 68% DeBakey I; 55% composite valved graft, 30% supracoronary ascending replacement, 15% valve-sparing aortic root replacement; 12% total arch replacement; 3% in-hospital mortality) at 2 tertiary centers in the United States and Europe over the past 25 years. The rate of aortic reintervention with resternotomy was 24% (18 of 74) and of descending aorta (thoracic+abdominal) intervention was 30% (22 of 74) at a median follow-up of 8.4 years (first and third quartiles, 2.2 and 12.7 years). Freedom from need for aortic root reoperation in patients who underwent primarily a composite valved graft or valve-sparing aortic root replacement procedure was 95±3%, 88±5%, and 79±5% and in patients who underwent supracoronary ascending replacement was 83±9%, 60±13%, 20±16% at 5, 10, and 20 years. Secondary aortic arch surgery was necessary only in patients with initial hemi-arch replacement. CONCLUSIONS: Emergency surgery for type A dissection in patients with Marfan syndrome is associated with low in-hospital mortality. Failure to extend the primary surgery to aortic root or arch repair leads to a highly complex clinical course. Aortic root replacement or repair is highly recommended because supracoronary ascending replacement is associated with a high need (>40%) for root reintervention.

Oxidative stress modulates vascular smooth muscle cell phenotype via CTGF in thoracic aortic aneurysm.

AIMS: Dissection and rupture of the ascending aorta are life-threatening conditions resulting in 80% mortality. Ascending aortic replacement in patients presenting with thoracic aortic aneurysm (TAA) is determined by metric measurement. However, a significant number of dissections occur outside of the parameters suggested by the current guidelines. We investigate the correlation among altered haemodynamic condition, oxidative stress, and vascular smooth muscle cell (VSMC) phenotype in controlling tissue homoeostasis. METHODS AND RESULTS: We demonstrate using finite element analysis (FEA) based on computed tomography geometries that TAA patients have higher wall stress in the ascending aorta than non-dilated patients. We also show that altered haemodynamic conditions are associated with increased levels of reactive oxygen species (ROS), direct regulators of the VSMC phenotype in the microregional area of the ascending aorta. Using in vitro and ex vivo studies on human tissues, we show that ROS accumulation correlates with media layer degeneration and increased connective tissue growth factor (CTGF) expression, which modulate the synthetic VSMC phenotype. Results were validated by a murine model of TAA (C57BL/6J) based on Angiotensin II infusion showing that medial thickening and luminal expansion of the proximal aorta is associated with the VSMC synthetic phenotype as seen in human specimens. CONCLUSIONS: Increased peak wall stress correlates with change in VSMC towards a synthetic phenotype mediated by ROS accumulation via CTGF. Understanding the molecular mechanisms that regulate VSMC towards a synthetic phenotype could unveil new regulatory pathways of aortic homoeostasis and impact the risk-stratification tool for patients at risk of aortic dissection and rupture.

Comparison of transesophageal echocardiographic analysis and circulating biomarker expression profile in calcific aortic valve disease.

BACKGROUND AND AIM OF THE STUDY: Aortic valve sclerosis (AVSc), the early asymptomatic stage of calcific aortic valve disease (CAVD), is characterized by a progressive thickening of the aortic cusps without obstruction of the left ventricular outflow. In spite of its high prevalence, there are no molecular markers to characterize the early stages of CAVD before it progresses to a severe, symptomatic stage of aortic valve stenosis (AVS). The study aim was to identify any correlation between circulating biomarkers and transesophageal echocardiography (TEE) evaluation. METHODS: A total of 330 patients with various degrees of CAVD was enrolled into the study. Blood was collected from each patient prior to surgery, and analyzed using ELISA kits following the manufacturers' instructions. RESULTS: Significantly higher plasma osteopontin (OPN) levels were observed in AVSc patients (72.7 +/- 1.8 ng/ml; p < 0.001) and AVS patients (64.3 +/- 5.1 ng/ml; p < 0.001) when compared to controls (30.3 +/- 1.8 ng/ml). Parathyroid hormone (PTH) levels in AVSc and AVS patients (164.1 +/- 16.5 and 134.3 +/- 14.6 pg/ml; p < 0.001 and p = 0.04, respectively) were also significantly higher than in controls (61.8 +/- 4.92 pg/ml). Upon further analysis, plasma levels of OPN (p < 0.001) and PTH (p < 0.001) were found to be significantly higher in asymptomatic AVSc patients, even before calcium deposition was detected on TEE evaluation. Fetuin-A levels were lower at all stages of CAVD when compared to controls (p < 0.001 and p < or = 0.05, respectively), but were comparable among the patient groups. NT-proBNP levels were significantly higher in AVS patients than in controls (p < or = 0.01). CONCLUSION: Serum levels of OPN, PTH, and fetuin-A showed a significant association with different stages of CAVD, with variations in their levels occurring before calcium nodules are visualized during TEE evaluation. The study results may help not only to provide a better understanding of the progression of CAVD but also to develop new tools that can be used to stage these patients.

Noggin attenuates the osteogenic activation of human valve interstitial cells in aortic valve sclerosis.

AIMS: Aortic valve sclerosis (AVSc) is a hallmark of several cardiovascular conditions ranging from chronic heart failure and myocardial infarction to calcific aortic valve stenosis (AVS). AVSc, present in 25-30% of patients over 65 years of age, is characterized by thickening of the leaflets with marginal effects on the mechanical proprieties of the valve making its presentation asymptomatic. Despite its clinical prevalence, few studies have investigated the pathogenesis of this disease using human AVSc specimens. Here, we investigate in vitro and ex vivo BMP4-mediated transdifferentiation of human valve interstitial cells (VICs) towards an osteogenic-like phenotype in AVSc. METHODS AND RESULTS: Human specimens from 60 patients were collected at the time of aortic valve replacement (AVS) or through the heart transplant programme (Controls and AVSc). We show that non-calcified leaflets from AVSc patients can be induced to express markers of osteogenic transdifferentiation and biomineralization through the combinatory effect of BMP4 and mechanical stimulation. We show that BMP4 antagonist Noggin attenuates VIC activation and biomineralization. Additionally, patient-derived VICs were induced to transdifferentiate using either cell culture or a Tissue Engineering (TE) Aortic Valve model. We determine that while BMP4 alone is not sufficient to induce osteogenic transdifferentiation of AVSc-derived cells, the combinatory effect of BMP4 and mechanical stretch induces VIC activation towards a phenotype typical of late calcified stage of the disease. CONCLUSION: This work demonstrates, for the first time using AVSc specimens, that human sclerotic aortic valves can be induced to express marker of osteogenic-like phenotype typical of advanced severe aortic stenosis.

Neurofibromatosis type 2 tumor suppressor protein, NF2, induces proteasome-mediated degradation of JC virus T-antigen in human glioblastoma.

Neurofibromatosis type 2 protein (NF2) has been shown to act as tumor suppressor primarily through its functions as a cytoskeletal scaffold. However, NF2 can also be found in the nucleus, where its role is less clear. Previously, our group has identified JC virus (JCV) tumor antigen (T-antigen) as a nuclear binding partner for NF2 in tumors derived from JCV T-antigen transgenic mice. The association of NF2 with T-antigen in neuronal origin tumors suggests a potential role for NF2 in regulating the expression of the JCV T-antigen. Here, we report that NF2 suppresses T-antigen protein expression in U-87 MG human glioblastoma cells, which subsequently reduces T-antigen-mediated regulation of the JCV promoter. When T-antigen mRNA was quantified, it was determined that increasing expression of NF2 correlated with an accumulation of T-antigen mRNA; however, a decrease in T-antigen at the protein level was observed. NF2 was found to promote degradation of ubiquitin bound T-antigen protein via a proteasome dependent pathway concomitant with the accumulation of the JCV early mRNA encoding T-antigen. The interaction between T-antigen and NF2 maps to the FERM domain of NF2, which has been shown previously to be responsible for its tumor suppressor activity. Co-immunoprecipitation assays revealed a ternary complex among NF2, T-antigen, and the tumor suppressor protein, p53 within a glioblastoma cell line. Further, these proteins were detected in various degrees in patient tumor tissue, suggesting that these associations may occur in vivo. Collectively, these results demonstrate that NF2 negatively regulates JCV T-antigen expression by proteasome-mediated degradation, and suggest a novel role for NF2 as a suppressor of JCV T-antigen-induced cell cycle regulation.

Antioxidant enzymes reduce DNA damage and early activation of valvular interstitial cells in aortic valve sclerosis.

OBJECTIVE: Accumulation of reactive oxygen species (ROS) and remodeling of the microstructure of the cusp characterize aortic valve sclerosis, the early phase of calcific aortic valve disease. These events are associated with activation of valvular interstitial cells (VICs) toward an osteogenic-like phenotype. Because ROS cause DNA damage and transcriptional activation we investigated the relationship between ROS, DNA damage response, and transdifferentiation of VICs. METHODS AND RESULTS: Human aortic valve cusps and patient-matched VICs were collected from 39 patients both with and without calcific aortic valve disease. VICs were exposed to hydrogen peroxide (0.1-1 mmol/L) after cell transduction with extracellular superoxide dismutase/catalase adenoviruses and characterized for DNA-damage response, osteogenic transdifferentiation, and calcification. ROS induce relocalization of phosphorylated γH2AX, MRE11, and XRCC1 proteins with expression of osteogenic signaling molecule RUNX2 via AKT. We report a sustained activation of γH2AX in aortic valve sclerosis-derived VICs suggesting their impaired ability to repair DNA damage. Adenovirus superoxide dismutase/catalase transduction decreases ROS-induced DNA damage and VIC transdifferentiation in aortic valve sclerosis-derived cells. Finally, adenoviral transduction with catalase reverts ROS-mediated calcification and cellular transdifferentiation. CONCLUSIONS: We conclude that the ROS-induced DNA damage response is dysfunctional in early asymptomatic stages of calcific aortic valve disease. We unveiled an association among ROS, DNA-damage response, and cellular transdifferentiation, reversible by antioxidant enzymes delivery.