Candidate plasma biomarkers for predicting ascending aortic aneurysm in bicuspid aortic valve disease.

BACKGROUND: Bicuspid aortic valve (BAV) disease is the most common congenital cardiac abnormality affecting 1-2% of the population and is associated with a significantly increased risk of ascending aortic aneurysm. However, predicting which patients will develop aneurysms remains a challenge. This pilot study aimed to identify candidate plasma biomarkers for monitoring ascending aortic diameter and predicting risk of future aneurysm in BAV patients. METHODS: Plasma samples were collected pre-operatively from BAV patients undergoing aortic valve surgery. Maximum ascending aortic diameter was measured on pre-operative transoesophageal echocardiography. Maximum diameter ≥ 45 mm was classified as aneurysmal. Sequential Window Acquisition of all THeoretical Mass Spectra (SWATH-MS), an advanced mass spectrometry technique, was used to identify and quantify all proteins within the samples. Protein abundance and aortic diameter were correlated using logistic regression. Levene's test was used to identify proteins demonstrating low abundance variability in the aneurysmal patients (consistent expression in disease), and high variability in the non-aneurysmal patients (differential expression between 'at risk' and not 'at risk' patients). RESULTS: Fifteen plasma samples were collected (seven non-aneurysmal and 8 aneurysmal BAV patients). The mean age of the patients was 55.5 years and the majority were female (10/15, 67%). Four proteins (haemoglobin subunits alpha, beta and delta and mannan-binding lectin serine protease) correlated significantly with maximal ascending aortic diameter (p < 0.05, r = 0.5-0.6). Five plasma proteins demonstrated significantly lower variability in the aneurysmal group and may indicate increased risk of aneurysm in non-aneurysmal patients (DNA-dependent protein kinase catalytic subunit, lumican, tetranectin, gelsolin and cartilage acidic protein 1). A further 7 proteins were identified only in the aneurysmal group (matrin-3, glucose-6-phosphate isomerase, coactosin-like protein, peptidyl-prolyl cis-trans isomerase A, golgin subfamily B member 1, myeloperoxidase and 2'-deoxynucleoside 5'-phosphate N-hydrolase 1). CONCLUSIONS: This study is the first to identify candidate plasma biomarkers for predicting aortic diameter and risk of future aneurysm in BAV patients. It provides valuable pilot data and proof of principle that could be used to design a large-scale prospective investigation. Ultimately, a more affordable 'off-the-shelf' follow-on blood assay could then be developed in place of SWATH-MS, for use in the healthcare setting

The role of hypoxia on interstitial mitral valve cells

Mitral valve disease is a multifactorial process. The valve is a complex structure that contains an amalgam of extracellular proteins, cellular components, nerves and blood vessels. It is predicted that some of the central portions of the valve leaflets could exist under hypoxic conditions. Hypoxia could play a role in initiating the structural changes in the valve that lead to dysfunction of the valve. It is known to cause the up-regulation of hypoxia-induced factor (HIF) that can regulate the differentiation of cells, the production of extracellular matrix (ECM) and expression of matrix remodelling enzymes, all of which are characteristic changes seen in one or more forms of the disease. This study aimed to investigate the effect of hypoxia on the basic behaviour and phenotypic profile of mitral valve interstitial cells (MVICs), and their functional response to produce and control the ECM components. The expression of HIF-1α and its role in mediating the effects induced by hypoxia were also investigated, and also the characteristics of blood vessels in the mitral valve leaflet in porcine as well as normal and diseased human valves. MVICs incubated under hypoxia remained viable and continued to grow, while retaining their morphology and phenotype. On the other hand, severe hypoxia resulted in reduced production of the ECM components sulphated glycosaminoglycan (sGAG) and collagen, while it induced matrix metabolism through up-regulating the gene expression of matrix metalloproteases and their tissue inhibitors. Human rheumatic valves had more evident expression of HIF-1α compared with normal or myxomatous degeneration valves. Porcine MVICs (pMVICs) expressed HIF-1α under hypoxia. Stimulating HIF-1α chemically causes a reduction in the amount of GAG produced, similar to the effect observed under severe hypoxia. The study also confirmed the presence of vascular supply to the normal mitral valve leaflets and showed that there was increased vascularisation in rheumatic valves, while there was a loss of vessels in myxomatous degenerative ones. In conclusion, normal mitral valve leaflets are vascular structures of variable pattern. Diseased valves are associated with changes in leaflet vascularity either by neovascularisation in rheumatic disease, or by loss of vascularisation in myxomatous degeneration. Hypoxia affects the production of certain ECM proteins and remodelling enzymes by MVICs. These effects appear to be mediated by the induction of HIF-1α. This study highlights an important process and mechanism in heart valve in health and disease and helps improve the understanding of its complex biology. This could have future implications on the treatment of valve disease and the future applications in heart valve tissue engineering.Open Acces

Knife in the superior mediastinum: Amazing escape

This text describe through images, how a knife is retrieved from the superior mediastinum

Feasibility of a novel, synthetic, self-assembling peptide for suture-line haemostasis in cardiac surgery

Abstract Backgroud To assess the feasibility and efficacy of PuraStat®, a novel haemostatic agent, in achieving suture line haemostasis in a wide range of cardiac surgical procedures and surgery of the thoracic aorta. Methods A prospective, non-randomised study was conducted at our institution. Operative data on fifty consecutive patients undergoing cardiac surgery where PuraStat® was utilised in cases of intraoperative suture line bleeding was prospectively collected. Questionnaires encompassing multiple aspects of the ease of use and efficacy of PuraStat® were completed by ten surgeons (five consultants and five senior registrars) and analysed to gauge the performance of the product. Results No major adverse cardiac events were reported in this cohort. Complications such as atrial fibrillation, pacemaker requirement and pleural effusions were comparable to the national average. Mean blood product use of packed red cells, platelets, fresh-frozen plasma (FFP) and cryoprecipitate was below the national average. There was one incidence of re-exploration, however this was due to pericardial constriction rather than bleeding. Analysis of questionnaire responses revealed that surgeons consistently rated PuraStat® highly (between a score of 7 and 10 in the various subcategories). The transparent nature or PuraStat® allowed unobscured visualisation of suture sites and possessed excellent qualities in terms of adherence to site of application. The application of PuraStat® did not interfere with the use of other haemostatic agents or manipulation of the suture site by the surgeon. Conclusion PuraStat® is an easy-to-use and effective haemostatic agent in a wide range of cardiac and aortic surgical procedures

Aortic Stenosis Prognostication in Patients With Type 2 Diabetes: Protocol for Testing and Validation of a Biomarker-Derived Scoring System

Background: Type 2 diabetes mellitus (T2DM) has been established as an important independent risk factor for aortic stenosis. T2DM patients present with a higher degree of valve calcification and left ventricular dysfunction compared to patients without diabetes. This may be due to an increase in incidence and severity of myocardial fibrosis. Currently, there is no reliable method of determining the optimal timing of intervention for a patient with asymptomatic aortic stenosis or predicting when a patient will become symptomatic. Research into serum biomarkers to predict subclinical onset and track progression of aortic stenosis is hampered by the multimodal nature of the pathological processes ultimately responsible for aortic stenosis.Objective: The aim of this study is to prove that an approach using a combination of serum biomarkers and the echocardiographic parameter global longitudinal strain (GLS) can be used to establish baseline status of fibrocalcific aortic valve disease, predict rate of progression, and quantitatively assess any regression of these processes following aortic valve replacement in patients with T2DM.Methods: Validated serum biomarkers for the separate processes of calcification, inflammation, oxidative stress and fibrosis can be used to quantify onset and rate of progression of aortic stenosis. This, in combination with the echocardiographic parameter GLS, can be compared with other objective investigations of calcification and fibrosis with the aim of developing a quick, noninvasive one-stop assessment of aortic stenosis in patients with T2DM. The serum biomarkers BNP (B-type natriuretic peptide), Gal-3 (Galectin-3), GDF-15 (growth differentiation factor-15), sST2 (soluble suppression of tumorigenicity 2), OPG (osteoprotegerin), and microRNA 19b and 21 will be sampled from patients undergoing aortic valve replacement (with and without T2DM), patients with T2DM but without aortic valve disease and healthy volunteers. These patients will also undergo computed tomography (CT) scans for calcium scoring, magnetic resonance imaging (MRI) to quantify myocardial fibrosis, and myocardial strain imaging with speckle-tracking echocardiography. Samples of calcified native aortic valve and a biopsy of ventricular myocardium will be examined histologically to determine the quantity and distribution of calcification and fibrosis, and the secretome of these tissue samples will also be analyzed for levels of the same biomarkers as in the serum samples. All patients will be followed up with in 3 months and 12 months for repeat blood sampling, echocardiography, and CT and MRI imaging to assess disease progression or regression. The results of tissue analysis and CT and MRI scanning will be used to validate the findings of the serum biomarkers and echocardiographic assessment.Results: Using all of the information gathered throughout the study will yield a ranking scale for use in the clinic, which will provide each patient with a fibrocalcific profile. This can then be used to recommend an optimal time for intervention.Conclusion: A reliable, validated set of serum biomarkers combined with an inexpensive bedside echocardiographic examination can now form the basis of a one-stop outpatient-based assessment service, which will provide an accurate risk assessment in patients with aortic stenosis at first contact

Candidate plasma biomarkers for predicting ascending aortic aneurysm in bicuspid aortic valve disease.

BACKGROUND: Bicuspid aortic valve (BAV) disease is the most common congenital cardiac abnormality affecting 1-2% of the population and is associated with a significantly increased risk of ascending aortic aneurysm. However, predicting which patients will develop aneurysms remains a challenge. This pilot study aimed to identify candidate plasma biomarkers for monitoring ascending aortic diameter and predicting risk of future aneurysm in BAV patients. METHODS: Plasma samples were collected pre-operatively from BAV patients undergoing aortic valve surgery. Maximum ascending aortic diameter was measured on pre-operative transoesophageal echocardiography. Maximum diameter ≥ 45 mm was classified as aneurysmal. Sequential Window Acquisition of all THeoretical Mass Spectra (SWATH-MS), an advanced mass spectrometry technique, was used to identify and quantify all proteins within the samples. Protein abundance and aortic diameter were correlated using logistic regression. Levene's test was used to identify proteins demonstrating low abundance variability in the aneurysmal patients (consistent expression in disease), and high variability in the non-aneurysmal patients (differential expression between 'at risk' and not 'at risk' patients). RESULTS: Fifteen plasma samples were collected (seven non-aneurysmal and 8 aneurysmal BAV patients). The mean age of the patients was 55.5 years and the majority were female (10/15, 67%). Four proteins (haemoglobin subunits alpha, beta and delta and mannan-binding lectin serine protease) correlated significantly with maximal ascending aortic diameter (p < 0.05, r = 0.5-0.6). Five plasma proteins demonstrated significantly lower variability in the aneurysmal group and may indicate increased risk of aneurysm in non-aneurysmal patients (DNA-dependent protein kinase catalytic subunit, lumican, tetranectin, gelsolin and cartilage acidic protein 1). A further 7 proteins were identified only in the aneurysmal group (matrin-3, glucose-6-phosphate isomerase, coactosin-like protein, peptidyl-prolyl cis-trans isomerase A, golgin subfamily B member 1, myeloperoxidase and 2'-deoxynucleoside 5'-phosphate N-hydrolase 1). CONCLUSIONS: This study is the first to identify candidate plasma biomarkers for predicting aortic diameter and risk of future aneurysm in BAV patients. It provides valuable pilot data and proof of principle that could be used to design a large-scale prospective investigation. Ultimately, a more affordable 'off-the-shelf' follow-on blood assay could then be developed in place of SWATH-MS, for use in the healthcare setting

Defective NOTCH signalling drives smooth muscle cell death and differentiation in bicuspid aortic valve aortopathy

OBJECTIVES: Bicuspid aortic valve disease is common and is associated with ascending aortic aneurysms. Vascular smooth muscle cell (VSMC) apoptosis is characteristic of the ascending aorta of bicuspid patients, and NOTCH1 gene mutations have also been linked to the disease. NOTCH signalling is a fundamental cell signalling pathway, which dictates cell fate decisions including apoptosis. Our objective was to elucidate the role of NOTCH signalling in VSMC apoptosis and differentiation in bicuspid aortopathy.METHODS: Ascending aortic biopsies were obtained from 19 bicuspid and 12 tricuspid aortic valve patients and were sub-classified into 4 groups according to the maximum ascending aortic diameter (aneurysmal  ≥45 mm). Apoptotic VSMCs were counted by light microscopy using a TUNEL assay. Gene expression of key regulators of NOTCH signalling (NOTCH1 and HES1), apoptosis (BAX and BCL-2) and VSMC differentiation (MYH11, CNN1 and MYH10) were quantified using quantitative real-time PCR. Primary VSMCs were cultured from 2 tricuspid aortic valve and 2 bicuspid aortic valve patients, NOTCH signalling was inhibited with N-[N-(3,5-Difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester, and the gene expression was again quantified.RESULTS: The apoptotic cell count was significantly higher in bicuspid aortic valve patients (3.2 cells/50 000 μm2 vs 1.1 cells/50 000 μm2; P = 0.033). There was a trend towards lower apoptotic cell count in the aneurysmal versus non-aneurysmal tricuspid and bicuspid groups and an increased ratio of proapoptotic gene expression, which was not statistically significant. This was associated with a 2.8-fold increase in contractile gene expression (P = 0.026) and a 2.0-fold increase in NOTCH signalling gene expression in bicuspid versus tricuspid aortic valve patients (P = 0.022). NOTCH inhibition in cultured VSMCs induced a similar pattern of increased proapoptotic and procontractile gene expressions.CONCLUSIONS: This preliminary study suggests that NOTCH activation in the non-aneurysmal bicuspid aortas may underlie aortopathy by influencing VSMC apoptosis and differentiation. NOTCH signalling manipulation may provide a therapeutic target for preventing aneurysms in bicuspid patients. Further studies with larger sample sizes are needed to substantiate the present findings

Additional file 1: of Candidate plasma biomarkers for predicting ascending aortic aneurysm in bicuspid aortic valve disease

Supplementary methods. (DOCX 25 kb