Molecular phenotyping and functional assessment of smooth muscle-like cells with pathogenic variants in aneurysm genes ACTA2, MYH11, SMAD3 and FBN1.

Aortic aneurysms (AAs) are pathological dilatations of the aorta. Pathogenic variants in genes encoding for proteins of the contractile machinery of vascular smooth muscle cells (VSMCs), genes encoding proteins of the transforming growth factor beta signaling pathway and extracellular matrix (ECM) homeostasis play a role in the weakening of the aortic wall. These variants affect the functioning of VSMC, the predominant cell type in the aorta. Many variants have unknown clinical significance, with unknown consequences on VSMC function and AA development. Our goal was to develop functional assays that show the effects of pathogenic variants in aneurysm-related genes. We used a previously developed fibroblast transdifferentiation protocol to induce VSMC-like cells, which are used for all assays. We compared transdifferentiated VSMC-like cells of patients with a pathogenic variant in genes encoding for components of VSMC contraction (ACTA2, MYH11), transforming growth factor beta (TGFß) signaling (SMAD3) and a dominant negative (DN) and two haploinsufficient variants in the ECM elastic laminae (FBN1) to those of healthy controls. The transdifferentiation efficiency, structural integrity of the cytoskeleton, TGFß signaling profile, migration velocity and maximum contraction were measured. Transdifferentiation efficiency was strongly reduced in SMAD3 and FBN1 DN patients. ACTA2 and FBN1 DN cells showed a decrease in SMAD2 phosphorylation. Migration velocity was impaired for ACTA2 and MYH11 cells. ACTA2 cells showed reduced contractility. In conclusion, these assays for showing effects of pathogenic variants may be promising tools to help reclassification of variants of unknown clinical significance in AA-related genes.

In vivo MR-angiography for the assessment of aortic aneurysms in an experimental mouse model on a clinical MRI scanner: Comparison with high-frequency ultrasound and histology.

BACKGROUND: MR-angiography currently represents one of the clinical reference-standards for the assessment of aortic-dimensions. For experimental research in mice, dedicated preclinical high-field MRI scanners are used in most studies. This type of MRI scanner is not available in most institutions. The aim of this study was to evaluate the potential of MR-angiography performed on a clinical MR scanner for the assessment of aortic aneurysms in an experimental mouse model, compared to a preclinical high-resolution ultrasound imaging system and histopathology. METHODS: All in vivo MR imaging was performed with a clinical 3T MRI system (Philips Achieva) equipped with a clinical gradient system in combination with a single-loop surface-coil (47 mm). All MR sequences were based on clinically used sequences. For ultrasound, a dedicated preclinical high-resolution system (30 MHz linear transducer, Vevo770, VisualSonics) was used. All imaging was performed with an ApoE knockout mouse-model for aortic aneurysms. Histopathology was performed as reference-standard at all stages of aneurysm development. RESULTS: MR-angiography on a clinical 3T system enabled the clear visualization of the aortic lumen and aneurysmal dilation at different stages of aneurysm development. A close correlation (R2 = 0.98; p < 0.001) with histological area measurements was found. Additionally, a good agreement between MR and ultrasound area measurements in systole (R2 = 0.91; p < 0.001) and diastole (R2 = 0.94; p < 0.001) were measured. Regarding interobserver reproducibility, MRI measurements yielded a smaller 95% confidence interval and a closer interreader correlation compared to ultrasound measurements (-0.37-0.46; R2 = 0.97 vs. -0.78-0.88; R2 = 0.87). CONCLUSION: This study demonstrates that MR-angiography, performed on a clinical 3T MR scanner, enables the reliable detection and quantification of the aortic dilatation at different stages of aneurysm development in an experimental mouse model.

Comparison of outcome in aortic dissection with single false lumen versus multiple false lumens: CT assessment.

PURPOSE: To investigate the clinical features and outcomes of type B multibarreled (multiple false lumens) aortic dissection (AD) compared with those of double-barreled (single false lumen) AD by using computed tomography (CT). MATERIALS AND METHODS: The ethics committee approved this study. Informed consent was waived. A total of 221 consecutive patients (127 men; median age, 62 years) with acute type B AD were evaluated by using CT. The clinical outcome, including AD-related events, AD-related deaths, and long-term survival, was retrospectively reviewed and compared with that of patients with double-barreled AD during the follow-up period (median, 60 months). Survival analysis was performed by using Kaplan-Meier analysis with the log-rank test within 10 years after onset. The Cox proportional hazards model was used to estimate the risk for AD-related events and death. RESULTS: In 201 of 221 patients (91.0%), double-barreled AD was identified at initial CT. In 20 of 221 patients (9%), multibarreled AD was identified at initial CT (n = 16) and follow-up CT (n = 4). In 15 of 20 patients (75%) with multibarreled AD, AD-related events occurred, and nine patients (45%) died of AD-related complications. Patients with multibarreled AD showed significantly poorer survival rates than patients with double-barreled AD (P = .0002). The presence of a multibarreled false lumen was the most powerful risk factor for AD-related deaths according to multivariate analysis (hazard ratio, 5.61; 95% confidence interval: 2.44, 12.90; P < .0001). CONCLUSION: Multibarreled AD occurs in 9% of acute type B dissections. The presence of multibarreled AD is a powerful predictor of AD-related deaths.

[Magnetic resonance imaging in long-term assessment after surgery for aortic coarctation]. / Valoración a largo plazo con resonancia magnética en pacientes corregidos de coartación de aorta.

OBJECTIVES: Spin echo or gradient echo magnetic resonance imaging provides enough information to plan patient management and can be completed with the use of three-dimensional magnetic resonance angiography to evaluate the need for reintervention, assess follow-up, or discharge the patient. PATIENTS AND METHODS: From 1990-2003, we evaluated 101 patients after initial corrective surgery for aortic coarctation at the age of 3.1 +/- 3 years, with subsequent postoperative assessment at 1 year and again 12.4 +/- 4.2 years later. No mortality was registered during the follow-up. Corrective surgery was performed in 32 patients (31.6 %) before the first month of life. All the patients were evaluated with spin-echo and echo gradient and 34 were evaluated with magnetic resonance angiography. The patients were classified into two groups: group A consisted of 68 patients (11 < 1 month old) with no complications. End-to-end anastomosis was performed in 55, the Alvarez technique in five, the Waldhausen technique in six, and conduit in two. Group B consisted of 33 patients complicated with early aortic recoarctation (21 corrected before the age of 1 month). End-to-end anastomosis was performed in 29, the Alvarez technique in two, and grafting in two. During the follow-up, 43 reinterventions were performed. Isthmus diameter/descending aorta diameter at the diaphragmatic level and repaired site diameter/descending aorta diameter at the diaphragmatic level were measured. RESULTS: Group A: the isthmus diameter/descending aorta diameter at the diaphragmatic level index was 0.92 +/- 0.08 and the repaired site diameter/ descending aorta diameter at diaphragmatic level index was 0.90 +/- 0.05. Twenty-three patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed two late stenosis (one in a 10-year-old patient with an end-to-end anastomosis performed previously, and another in an 18-year-old patient with a proximal and distal obstructed conduit). Group B: the isthmus diameter/descending aorta diameter index was 0.84 +/- 0.1 and the repaired site diameter/ descending aorta diameter index was 0.82 +/- 0.11. Eleven patients were assessed by means of three-dimensional magnetic resonance angiography, which revealed five stenosis indexes (0.53-0.73) surgically corrected before the age of 2 months, four with an initial technique based on end-to-end anastomosis and one with a graft. CONCLUSIONS: Our results support the influence of young age, the use of end-to-end anastomosis and grafts in recoarctation and their late influence on recurrent recoarctation. The patients in group A were discharged in childhood or adulthood after periodic follow-up every 5 years with magnetic resonance angiography for 18 years with results within the normal range, while patients in group B required longer follow-up.

Transesophageal echocardiography and magnetic resonance imaging for the assessment of saccular aneurysm of the transverse thoracic aorta.

We report a patient who initially presented with hoarseness and was admitted to our hospital with chest pain, caused by a saccular aneurysm of the thoracic aortic arch. The initial diagnosis was made by cross-sectional echocardiography, the extension and morphology of the saccular aneurysm being detected by transesophageal echocardiography. Magnetic resonance imaging confirmed the measurements of the aneurysm and clearly showed the anatomic relation with surrounding structures and arch vessels. The patient refused operation and died during in-hospital stay. A rupture of the thoracic aneurysm was the cause of death.

Assessment of the role of pancreatic proteases in human abdominal aortic aneurysms and occlusive disease.

Previous studies on the pathogenesis of abdominal aortic aneurysms have shown both elastase-like activity in the aortic wall and a decreased elastin content. The present study, using specific radioimmunoassays for pancreatic elastase 2 (IRE2) and cationic trypsin(ogen) (IRCT), investigates the concentrations of these proteases which are known to circulate in blood, in abdominal aortic aneurysms. Aortic specimens were obtained from 32 patients with aneurysms and 21 patients with atherosclerotic occlusive disease. Aortic tissue, obtained at autopsy from young adults, served as controls. Elastase-like activity was 300% and 800% higher, respectively, in aortic homogenates from aneurysms in comparison to occlusive disease and control aortic tissue. This was associated with 1.4-fold higher level of IRE2 and 2.7-fold higher levels of IRCT as compared to occlusive disease. Although there was no significant difference in the aortic collagen concentration among all 3 groups, the elastin content of aneurysmal aorta was 85% and 74% lower, respectively, in comparison to control and occlusive aorta. The results of this investigation demonstrate the presence of pancreatic elastase 2 and cationic trypsin(ogen) in abdominal aortic aneurysmal tissue and suggest that circulating pancreatic proteases contribute to the pathophysiology of aneurysms of the infrarenal aorta.

The role of intraoperative two-dimensional echocardiography in the assessment of thoracic aorta pathology.

The role of intraoperative two-dimensional echocardiography is discussed in 15 consecutive patients with thoracic aorta pathology undergoing cardiac surgery. A 5 MHz mechanical scanner was used before and immediately after cardiopulmonary bypass. In 5 patients intraoperative two-dimensional studies revealed crucial morphologic information which, consequently, had a marked influence on their planned surgical procedure. In 3 patients the findings provided additional information whereas in the remaining patients the intraoperative echocardiographic findings confirmed the preoperative diagnosis. Following surgery the adequacy of cardiac repair was assessed and, in one patient, epicardial echocardiography indicated the necessity for reoperation. The application of intraoperative two-dimensional echocardiography leads to a better understanding of the pathology involved and facilitates a more appropriate decision concerning the surgical procedure.