Abnormal extracellular matrix protein transport associated with increased apoptosis of vascular smooth muscle cells in Marfan syndrome and bicuspid aortic valve thoracic aortic aneurysm

Background - Marfan syndrome (MS) is a genetic disorder caused by a mutation in the fibrillin gene FBN1. Bicuspid aortic valve (BAV) is a congenital heart malformation of unknown cause. Both conditions are associated with ascending aortic aneurysm and premature death. This study examined the relationship among the secretion of extracellular matrix proteins fibrillin, fibronectin, tenascin, and vascular smooth muscle cell (VSMC) apoptosis. The role of matrix metalloproteinase (MMP)- 2 in VSMC apoptosis was studied in MS aneurysm. Methods and Results - Aneurysm tissue was obtained from patients undergoing surgery ( MS: 4 M, 1 F, age 27 - 45 years; BAV: 3 M, 2 F, age 28 - 65 years). Normal aorta from subjects with nonaneurysm disease was also collected ( 4 M, 1 F, age 23 - 93 years). MS and BAV aneurysm histology showed areas of cystic medial necrosis (CMN) without inflammatory infiltrate. Immunohistochemical study of cultured MS and BAV VSMC showed intracellular accumulation and reduction of extracellular distribution of fibrillin, fibronectin, and tenascin. Western blot showed no increase in expression of fibrillin, fibronectin, or tenascin in MS or BAV VSMC and increased expression of MMP-2 in MS VSMCs. There was 4-fold increase in loss of cultured VSMC incubated in serum-free medium for 24 hours in both MS ( 27 +/- 8%) and BAV ( 32 +/- 14%) compared with control ( 7 +/- 5%). Conclusions - In MS and BAV there is alteration in both the amount and quality of secreted proteins and an increased degree of VSMC apoptosis. Up-regulation of MMP-2 might play a role in VSMC apoptosis in MS VSMC. The findings suggest the presence of a fundamental cellular abnormality in BAV thoracic aorta, possibly of genetic origin.

Quantification of aortic flow by phase-contrast magnetic resonance in patients with bicuspid aortic valve.

AIMS: Bicuspid aortic valve (BAV) causes complex flow patterns in the ascending aorta (AAo), which may compromise the accuracy of flow measurement by phase-contrast magnetic resonance (PC-MR). Therefore, we aimed to assess and compare the accuracy of forward flow measurement in the AAo, where complex flow is more dominant in BAV patients, with flow quantification in the left ventricular outflow tract (LVOT) and the aortic valve orifice (AV), where complex flow is less important, in BAV patients and controls. METHODS AND RESULTS: Flow was measured by PC-MR in 22 BAV patients and 20 controls at the following positions: (i) LVOT, (ii) AV, and (iii) AAo, and compared with the left ventricular stroke volume (LVSV). The correlation between the LVSV and the forward flow in the LVOT, the AV, and the AAo was good in BAV patients (r = 0.97/0.96/0.93; P < 0.01) and controls (r = 0.96/0.93/0.93; P < 0.01). However, in relation with the LVSV, the forward flow in the AAo was mildly underestimated in controls and much more in BAV patients [median (inter-quartile range): 9% (4%/15%) vs. 22% (8%/30%); P < 0.01]. This was not the case in the LVOT and the AV. The severity of flow underestimation in the AAo was associated with flow eccentricity. CONCLUSION: Flow measurement in the AAo leads to an underestimation of the forward flow in BAV patients. Measurement in the LVOT or the AV, where complex flow is less prominent, is an alternative means for quantifying the systolic forward flow in BAV patients.

Successful Transapical Aortic Valve Implantation in a Congenital Bicuspid Aortic Valve.

Transcatheter stent-valve implantation in stenosed congenital bicuspid aortic valves is under debate. Heavily calcified elliptic bicuspid valves represent a contraindication to catheter-based valve therapies because of a risk of stent-valve displacement, distortion, or malfunctioning after the implantation. In this case report we illustrate our experience with a patient suffering from stenosed congenital bicuspid aortic valve who successfully underwent a transapical 26-mm Edwards Sapien stent-valve (Edwards Lifesciences Inc, Irvine, CA) implantation. Postoperative distortion, malfunctioning, and paravalvular leaks were not detected.

Proteomic alterations in heat shock protein 27 and identification of phosphoproteins in ascending aortic aneurysm associated with bicuspid and tricuspid aortic valve

Whether or not there are molecular differences, at the intra- and extracellular level, between aortic dilatation in patients with bicuspid (BAV) and those with a tricuspid aortic valve (TAV) has remained controversial for years. We have performed 2-dimensional gel electrophoresis and mass spectrometry coupled with dephosphorylation and phosphostaining experiments to reveal and define protein alterations and the high abundant structural phosphoproteins in BAV compared to TAV aortic aneurysm samples. 2-D gel patterns showed a high correlation in protein expression between BAV and TAV specimens (n=10). Few proteins showed significant differences, among those a phosphorylated form of heat shock protein (HSP) 27 with significantly lower expression in BAV compared to TAV aortic samples (p=0.02). The phosphoprotein tracing revealed four different phosphoproteins including Rho GDP dissociation inhibitor 1, calponin 3, myosin regulatory light chain 2 and four differentially phosphorylated forms of HSP27. Levels of total HSP27 and dually phosphorylated HSP27 (S78/S82) were investigated in an extended patient cohort (n=15) using ELISA. Total HSP27 was significantly lower in BAV compared to TAV patients (p=0.03), with no correlation in levels of phospho-HSP27 (S78/S82) (p=0.4). Western blots analysis showed a trend towards lower levels of phospho-HSP27 (S78) in BAV patients (p=0.07). Immunohistochemical analysis revealed that differences in HSP27 occur in the cytoplasma of VSMC's and not extracellularly. Alterations in HSP27 may give early evidence for intracellular differences in aortic aneurysm of patients with BAV and TAV. Whether HSP27 and the defined phosphoproteins have a specific role in BAV associated aortic dilatation remains to be elucidated.

Syndromic and non-syndromic aneurysms of the human ascending aorta share activation of the Smad2 pathway

Common features such as elastic fibre destruction, mucoid accumulation, and smooth muscle cell apoptosis are co-localized in aneurysms of the ascending aorta of various aetiologies. Recent experimental studies reported an activation of TGF-beta in aneurysms related to Marfan (and Loeys-Dietz) syndrome. Here we investigate TGF-beta signalling in normal and pathological human ascending aortic wall in syndromic and non-syndromic aneurysmal disease. Aneurysmal ascending aortic specimens, classified according to aetiology: syndromic MFS (n = 15, including two mutations in TGFBR2), associated with BAV (n = 15) or degenerative forms (n = 19), were examined. We show that the amounts of TGF-beta 1 protein retained within and released by aneurysmal tissue were greater than for control aortic tissue, whatever the aetiology, contrasting with an unchanged TGF-beta 1 mRNA level. The increase in stored TGF-beta 1 was associated with enhanced LTBP-I protein and mRNA levels. These dysiregulations of the extracellular ligand are associated with higher phosphorylated Smad2 and Smad2 mRNA levels in the ascending aortic wall from all types of aneurysm. This activation correlated with the degree of elastic fibre fragmentation. Surprisingly, there was no consistent association between the nuclear location of pSmad2 and extracellular TGF-beta 1 and LTBP-I staining and between their respective mRNA expressions. In parallel, decorin. was focally increased in aneurysmal media, whereas biglycan was globally decreased in aneurysmal aortas. In conclusion, this study highlights independent dysregulations of TGF-beta retention and Smad2 signalling in syndromic and non-syndromic aneurysms of the ascending aorta. Copyright (C) 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Pulpal heat changes with newly developed resin photopolymerisation systems

Composite resin is a widely-used direct tooth coloured restorative material. Photoactivation of the polymerisation reaction can be achieved by visible blue light from a range of light sources, including halogen lamps, metal halide lamps, plasma arc lamps, and Light Emitting Diode (LED) lights. Concerns have been raised that curing lights may induce a temperature rise that could be detrimental to the vitality of the dental pulp during the act of photoactivation. The present study examined heat changes associated with standardised class V restorations on the buccal surface of extracted premolar teeth, using a curing time of 40 seconds. The independent effects of type of light source, resin shade and remaining tooth thickness were assessed using a matrix experimental design. When a conventional halogen lamp, a metal halide lamp and two different LED lights were compared, it was found that both LED lamps elicited minimal thermal changes at the level of the dental pulp, whereas the halogen lamp induced greater changes and the metal halide lamp caused the greatest thermal insult of all the light sources. These thermal changes were influenced by resin shade, with different patterns for LED versus halogen or halide sources. Thermal stress reduced as the remaining thickness of tooth structure between the pulp and the cavity floor increased. From these results, it is concluded that LED lights produce the least thermal insult during photopolymerisation of composite resins.

Operação de Ross: Resultados a Médio Prazo

The Ross procedure has been used in children and young adults for aortic valve replacement and the correction of complex obstruction syndromes of the left ventricular outflow tract. We report the mid-term results of the Ross procedure in a single institution and performed by the same surgical team. Population: Between March 1999 and December 2005, 18 patients were operated on using the Ross procedure. The mean age at the time of surgery was 12 years, being 12 patients male (67%). The primary indication for surgery was isolated aortic valve disease, being the predominant abnormality in 58% of cases aortic regurgitation and in 42% left ventricular outflow tract obstruction. Associated lesions included sub-aortic membrane in 3 patients (16%), small VSD in 2 patients (11%), bicuspid aortic valve in 4 patients (22%) and severe left ventricular dysfunction and mitral valve regurgitation in 1 patient (6%). Ten of the 18 patients (56%) had been submitted to previous surgical procedures or percutaneous interventions. Results: Early post-operative mortality was not seen, but two patients (11%), had late deaths, one due to endocarditis, a year after the Ross procedure, and the other due to dilated cardiomiopathy and mitral regurgitation. The shortest time of follow-up is 6 months and the longest 72 months (median 38 months). Of the 16 survivors, 14 patients are in class I of the NYHA and 2 in class II, without significant residual lesions or need for re-intervention. The 12 patients with more than a year of follow up revealed normal coronary perfusion in all patients and no segmental wall motion abnormalities. Nevertheless, two of the 12 patients developed residual dynamic obstruction of LVOT and in three patients aortic regurgitation of a mild to moderate degree was evident. Significant gradients were not verified in the RVOT. Conclusions: The Ross procedure, despite its complexity, can be undertaken with excellent immediate results. Aspects such as the dilation of the neo aortic root and homograft evolution can not be considered in a study of this nature, seeing that the mean follow up time does not exceed 5 years.

Fusobacterium necrophorum causing infective endocarditis and liver and splenic abscesses

A 25-year-old male without prior co-morbidities was admitted to hospital with Fusobacterium necrophorum bacteremia, where he was found to have liver and splenic abscesses. Further evaluation with echocardiography revealed a bicuspid aortic valve with severe insufficiency and a 1.68 x 0.86 cm vegetation. The patient required abscess drainage, intravenous antimicrobial therapy and aortic valve replacement. Complete resolution of the infection was achieved after valve replacement and a prolonged course of intravenous antimicrobial therapy. A brief analysis of the patient's clinical course and review of the literature is presented.

Mosaic Trisomy 18 in a Five-Month-Old Infant - Case Report

Individuals with mosaic trisomy 18, only approximately 5% of all trisomy 18 cases, carry both a trisomy 18 and an euploid cell line. Their clinical findings are highly variable, from the absence of dysmorphic features to the complete trisomy 18 syndrome. A five month old daughter of a 38-year-old mother, with vomiting and feeding problems, was referred to our department. She was undernourished and had axial hypotony and developmental delay, an irregular pattern of hypopigmentation on the right side of the abdomen, and moderate sagittal body asymmetry with left-side muscular hemihypotrophy.Mild craniofacial dysmorphy included dolichocephaly, frontal bossing, prominent occiput, long downslanting palpebral fissures, hypertelorism, and retrognathia. A complex heart defect with atrial and ventricular septal defects, pulmonary artery stenosis, and bicuspid aortic valve was identified. Cytogenetic analysis revealedmosaic trisomy 18with trisomy in 90%of peripheral lymphocytes and 17%of skin fibroblasts.This case adds to our knowledge of the phenotypic spectrum and the natural history of mosaic trisomy 18 by adding a dysmorphic feature and a cardiac abnormality that, to the best of our knowledge, had not been previously described.

Association of pulmonary atresia with intact ventricular septum and aortic valve stenosis. Prenatal diagnosis

A rare association of pulmonary atresia with an intact septum was diagnosed through echocardiography in a fetus 32 weeks of gestational age. The diagnosis was later confirmed by echocardiography of the newborn infant and further on autopsy. The aortic valve was bicuspid with a pressure gradient of 81mmHg, and the right ventricle was hypoplastic, as were the pulmonary trunk and arteries, and the blood flow was totally dependent on the ductus arteriosus.