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Heart Valves (heart + valve)
Kinds of Heart Valves Terms modified by Heart Valves Selected AbstractsMechanical Heart Valves in SeptuagenariansJOURNAL OF CARDIAC SURGERY, Issue 1 2008Ch.M., F.E.T.C.S., F.R.C.S., R. Ascione M.D. Methods: The study was carried out in a tertiary regional hospital in South-West England. Study 1: Consecutive series of 567 patients undergoing Sorin Bileaflet (SB) mechanical valve implant (437 patients < 70 years; 130 patients , 70 years). Study 2: 113 septuagenarians undergoing biological implant matched on age, valve type, concomitant coronary surgery, and operative priority to the SB septuagenarian group. Main outcome measures included in-hospital mortality and morbidity and mid-term valve-related outcome. Results: Study 1: Septuagenarians were more likely to present with coronary disease, and to undergo coronary surgery (p < 0.01). In-hospital mortality was 2.8% and 2.3% (p = 0.79) and neurological complications 1.4% versus 3.8% (p = 0.026) in the younger and older groups, respectively. Valve-related mortality at two years was 1.8% (95%CI, 0.8% to 3.6%) and 4.8% (95% CI, 2.0% to 9.7%); cumulative three- year incidence of thromboembolic or major hemorrhagic event was 8.3% (95% CI, 5.7% to 12.0%) and 4.6% (95% CI, 1.7% to 12.4%) in the younger and older groups, respectively. Study 2: In-hospital mortality was 1.8% and 7.1% in the SB and biological groups, respectively (ratio 0.25; 95% CI, 0.05 to 1.18, p = 0.058). The incidence of acute renal failure was greater in the biological group (risk ratio 0.30; 95% CI, 0.09 to 0.98, p = 0.035). There was no difference in mid-term valve-related mortality between groups (hazard ratio 0.53; 95% CI, 0.18 to 1.52, p = 0.24). Conclusion: The performance of SB valve in septuagenarians seems to be effective with no increased risk of in-hospital mortality, bleeding, or thromboembolic events. [source] Detergent Decellularization of Heart Valves for Tissue Engineering: Toxicological Effects of Residual Detergents on Human Endothelial CellsARTIFICIAL ORGANS, Issue 3 2010Serghei Cebotari Abstract Detergents are powerful agents for tissue decellularization. Despite this, the high toxicity of detergent residua can be a major limitation. This study evaluated the efficacy of detergent removal from decellularized pulmonary valves (PVs) and the consequences of repopulation with human endothelial cells (HECs). Porcine PVs were treated with 1% sodium deoxycholate (SDC), group A; 1% sodium dodecyl sulfate (SDS), group B; and a mixture of 0.5% SDC/0.5% SDS, group C (n = 5 each). After each of 10 succeeding wash cycles (WCs), samples of the washing solution (WS) were analyzed by solid phase extraction and high performance liquid chromatography for the presence of detergents. Metabolic activity of HEC was also assessed in the WS samples (cytotoxicity and MTS assays). Decellularized and washed PVs were reseeded with HEC. Histological analysis demonstrated efficient tissue decellularization in all groups. Detergents' concentration in all WSs decreased exponentially and was below 50 mg/L after 6, 8, and 4 WCs in groups A, B, and C, respectively. This concentration resulted in no significant toxic influence on cell cultures, and scaffolds could be efficiently reseeded with HEC. In conclusion, intensive washing of detergent decellularized valvular scaffolds lowers the residual contamination below a hazardous threshold and allows their successful repopulation with HEC for tissue engineering purposes. [source] Tissue Engineered Heart Valves: Autologous Cell Seeding on Biodegradable Polymer ScaffoldARTIFICIAL ORGANS, Issue 5 2002Toshiharu Shinoka Abstract: We previosly reported on the successful creation of tissue-engineered valve leaflets and the implantation of these autologous tissue leaflets in the pulmonary valve position. Mixed cell populations of endothelial cells and fibroblasts were isolated from explanted ovine arteries. Endothelial cells were selectively labeled with an acetylated low-density lipoprotein marker and separated from fibroblasts using a fluorescent activated cell sorter. A synthetic biodegradable scaffold consisting of polyglycolic acid fibers was seeded first with fibroblasts then subsequently coated with endothelial cells. Using these methods, autologous cell/polymer constructs were implanted in 6 animals. In 2 additional control animals, a leaflet of polymer was implanted without prior cell seeding. In each animal, using cardiopulmonary bypass, the right-posterior leaflet of the pulmonary valve was resected completely and replaced with an engineered valve leaflet with (n = 6) or without (n = 2) prior cultured cell seeding. After 6 h and 1, 6, 7, 9, and 11 weeks, the animals were sacrificed and the implanted valve leaflets were examined histologically, biochemically, and biomechanically. Animals receiving leaflets made from polymer without cell seeding were sacrificed and examined in a similar fashion after 8 weeks. In the control animals, the acellular polymer leaflets were degraded completely leaving no residual leaflet tissue at 8 weeks. The tissue-engineered valve leaflet persisted in each animal in the experimental group; 4-hydroxyproline analysis of the constructs showed a progressive increase in collagen content. Immunohistochemical staining demonstrated elastin fibers in the matrix and factor VIII on the surface of the leaflet. The cell labeling experiments demonstrated that the cells on the leaflets had persisted from the in vitro seeding of the leaflets. In the tissue-engineered heart valve leaflet, transplanted autologous cells generated proper matrix on the polymer scaffold in a physiologic environment at a period of 8 weeks after implantation. [source] The Complexity of External Acoustic Detection of Defects in Björk-Shiley Convexoconcave Heart ValvesARTIFICIAL ORGANS, Issue 1 2001Bas A. De Mol Abstract: Fractures in Björk-Shiley convexoconcave (BScc) heart valves have raised questions about the feasibility of early diagnosis of technical defects by means of acoustic assessment. Three laboratory tests were conducted. To establish acoustic fingerprints, 66 valves with a defect, such as single-leg fracture (SLF) or single-leg separation (SLS), or without a defect were connected with a contact sensor and excited by dropping a small metal ball onto the outlet strut. In the second test, we simulated the valve sound propagation within the thorax. In the third test, intact, SLF, and SLS valves were placed in a mock heart immersed in a large water tank. We observed a resonance frequency corresponding with valve size and presence of defects. The second test showed that both the chest wall and the lungs created numerous reflections. This led to a substantial overlap of the original pulse frequencies and the frequencies measured. The third test confirmed that submersion of the chest in water can significantly reduce chest wall reflections. Reliable noninvasive assessment of BScc valve clicks for the presence of defects of the outlet strut is hampered by complex sound propagation within the thorax and variability of valve excitation. Acoustic fingerprints to diagnose mechanical defects should be integrated in valve design. [source] The oral health of children considered very high risk for infective endocarditisINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 3 2010RICHARD BALMER International Journal of Paediatric Dentistry 2010; 20: 173,178 Background., Children with previous experience of infective endocarditis or with prosthetic heart valve are considered at very high risk for infective endocarditis. Aim., The aim of this study was to compare the dental health of a group of these children with a group of healthy controls and to determine parental awareness of the importance of good oral health. Design., Oral examination was carried out in 28 children with previous infective endocarditis or a prosthetic heart valve to assess oral health. Findings were compared to a healthy control group of 28. Questionnaires were distributed to the parents to assess awareness of oral health. Results., There was no significant difference in DMFT scores of study and control group (2.43 +/- 3.72 and 1.36 +/- 2.5 respectively) or in DMFT scores of study and control group (1.5 +/- 1.73 and 1.15 +/- 1.42 respectively), 36% of the study group had untreated caries. Parental knowledge of the link between oral health and infective endocarditis was excellent. Conclusions., There were no significant differences between the oral health of cardiac children and healthy children although the dmft and DMFT scores of the study group were high. Of concern was the proportion of children with untreated caries in spite of good dental awareness and attendance. [source] Foetal cerebral hemispheric atrophy and porencephaly after intrauterine exposure to maternal warfarin for mechanical prosthetic heart valvePRENATAL DIAGNOSIS, Issue 2 2008Giuliana Simonazzi No abstract is available for this article. [source] Tissue Engineering of Heart Valves In Vivo Using Bone Marrow-derived CellsARTIFICIAL ORGANS, Issue 7 2006Sang-Soo Kim Abstract:, In this study, we tissue-engineered heart valves in vivo using autologous bone marrow-derived cells (BMCs). Canine BMCs were differentiated into endothelial cell (EC)-like cells and myofibroblast (MF)-like cells. Decellularized porcine pulmonary valves were seeded with BMCs and implanted to abdominal aorta and pulmonary valve of bone marrow donor dogs. Histological examination of the explants identified the regeneration of valvular structures expressing CD31 and smooth muscle ,-actin, indicating the presence of EC-like and MF-like cells in the grafts at 3 and 1 week, respectively, after implantation. Fluorescent microscopic examinations identified the presence of fluorescently labeled cells in the explants, indicating that the implanted BMCs survived and participated in the heart valve reconstitution. This study reports, for the first time, on tissue engineering of heart valve in vivo using BMCs. [source] First percutaneous transcatheter aortic valve-in-valve implant with three year follow-upCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2008Carlos E. Ruiz MD, FSCAI Abstract Objectives: This study was conducted to report the clinical, hemodynamic, and iconographic outcomes of the longest survivor of the global CoreValve experience. Background: Early results of percutaneous heart valve (PHV) implantation for severe symptomatic aortic stenosis (AS) have been encouraging, with mid term survival up to 2 years; however longer durability term is unknown. Although a PHV has been implanted in a degenerated surgical bioprosthesis, the feasibility of a PHV-in-PHV has not been demonstrated. Methods: A patient with severe refractory heart failure due to severe aortic regurgitation (AR) and moderate AS, underwent CoreValve prosthesis implantation. The PHV was deployed too proximal into the left ventricular outflow tract, resulting in severe AR through the frame struts. Using the first PHV as a landmark, a second CoreValve was then deployed slightly distal to the first, with trivial residual paravalvular leak. Results: The second CoreValve expanded well with proper function. Transvalvular gradient was 8 mmHg. Both coronary ostia were patent. New mild to moderate mitral regurgitation occurred due to impingement of the anterior mitral leaflet by the first PHV. NYHA functional class improved from IV to II, maintained over the past 3 years. Echocardiography at 3 years showed normal functioning CoreValve-in-CoreValve prostheses, without AR or paravalvular leaks. Transvalvular gradient was 10 mmHg. Cardiac CT showed stable valve-in-valve protheses with no migration. Conclusion: The CoreValve prosthesis has maintained proper function up to 3 years, with no structural deterioration or migration. Treating mixed aortic valve disease with predominant AR is feasible. The concept as well as durability of the first PHV-in-PHV has also been demonstrated. © 2008 Wiley-Liss, Inc. [source] The Role of Natriuretic Peptides in Patients With Chronic Complex (Mixed or Multiple) Heart Valve DiseaseCONGESTIVE HEART FAILURE, Issue 2 2010FRACP, Naylin Bissessor MBChB N-terminal prohormone B-type natriuretic peptide (NT-proBNP) is an important biomarker of prognosis in heart failure and single valve disease. There are limited studies of complex valve disease. Patients with complex valve disease adopt a sedentary lifestyle, so symptoms may be difficult to detect. The authors aimed to determine whether NT-proBNP correlates with the severity of the valve lesion and underlying cardiac function and whether resting NT-proBNP predicts impaired peak VO2 in patients with complex valve disease. Forty-five patients with complex moderate to severe stenosis or regurgitation of the heart valves underwent a clinical assessment, echocardiography, resting NT-proBNP assessment, and formal cardiopulmonary exercise testing. In a multivariate analysis, the log NT-proBNP (,=,9.3, SE=1.9, P<.0001) and lean body weight (,=0.59, SE=0.22, P=.01) were dominant independent predictors of peak VO2. An NT-proBNP value of 84 pmol/L had 77% sensitivity and 70% specificity to predict impaired functional capacity, peak VO2 <60% (predicted), area under the curve=0.80. Resting NT-proBNP was the best predictor of peak VO2 in patients with complex valve disease, while symptoms and ejection fraction are a less reliable guide. Congest Heart Fail. 2010;16:50,54. © 2009 Wiley Periodicals, Inc. [source] Characterization of molecular markers to assess cardiac cushions formation in XenopusDEVELOPMENTAL DYNAMICS, Issue 12 2009Young-Hoon Lee Abstract The valves and septa of the mature heart are derived from the cardiac cushions, which develop from discrete swellings in two regions of developing heart tube: the atrioventricular (AV) canal and the ventricular outflow tract (OFT). In higher vertebrates, three distinct lineages contribute to the heart valves and septa, the endocardium, the myocardium, and the cardiac neural crest that will populate the cardiac jelly of the OFT. Very little is known about cardiac cushions development in amphibians. Here, we describe the expression of eight genes during key stages of cardiac cushion development in Xenopus. Among these genes, the Wnt antagonist Frzb1 and the transcription factors Xl-Fli, Sox8, Sox9, and Sox10 are differentially expressed in the mesenchyme of the OFT and AV cushions. These genes can be used in combination with lineage-tracing experiments to determine the embryonic origin of the cardiac cushions mesenchyme in Xenopus. Developmental Dynamics 238:3257,3265, 2009. © 2009 Wiley-Liss, Inc. [source] Vascular endothelial growth factor receptor signaling is required for cardiac valve formation in zebrafishDEVELOPMENTAL DYNAMICS, Issue 1 2006You Mie Lee Abstract Vascular endothelial growth factor-receptors (VEGF-Rs) are pivotal regulators of vascular development, but a specific role for these receptors in the formation of heart valves has not been identified. We took advantage of small molecule inhibitors of VEGF-R signaling and showed that blocking VEGF-R signaling with receptor selective tyrosine kinase inhibitors, PTK 787 and AAC 787, from 17,21 hr post-fertilization (hpf) in zebrafish embryos resulted in a functional and structural defect in cardiac valve development. Regurgitation of blood between the two chambers of the heart, as well as a loss of cell-restricted expression of the valve differentiation markers notch 1b and bone morphogenetic protein-4 (bmp - 4), was readily apparent in treated embryos. In addition, microangiography revealed a loss of a definitive atrioventricular constriction in treated embryos. Taken together, these data demonstrate a novel function for VEGF-Rs in the endocardial endothelium of the developing cardiac valve. Developmental Dynamics 235:29,37, 2006. © 2005 Wiley-Liss, Inc. [source] ORIGINAL INVESTIGATIONS: Tissue Harmonic Imaging in Echocardiography: Better Valve Imaging, But at What Cost?ECHOCARDIOGRAPHY, Issue 2 2008Karin Hawkins M.D. Background: Tissue harmonic imaging (THI) improves echocardiographic image quality and is widely utilized. Unfortunately it also makes structures appear artificially thickened. We sought to examine its impact on the imaging of left-sided heart valves. Methods: A large echocardiographic database was searched for full, standard transthoracic echocardiographic exams performed 12-month periods before (n = 3,786) and after (n = 3,914) transition to THI at a single institution. Patients with prosthetic valves were excluded. Results: The mean age of patients was 63 ± 17 years and 65% were men. No appreciable difference in demographics was observed between time periods. While inadequate visualization of the mitral valve was reduced by 30% using THI (P = 0.014), reports of leaflet thickening increased by 28% (P = 0.005). Similarly, inadequate aortic valve visualization was reduced by 53% with THI (P < 0.001), at the expense of more aortic sclerosis (+6%, P = 0.034). Among the 480 patients with echocardiograms using each modality (time interval between studies: 370 ± 143 days), THI did not appreciably improve visualization of the either valve. Although no significant increase in mitral thickness was seen with THI, aortic sclerosis was increased by at least one grade in 24.5% (P < 0.006). Conclusion: This study suggests that while THI enhances imaging of difficult to visualize valves, it may overestimate mitral and aortic valve thickness. This could lead to overdiagnosis and unnecessary follow-up studies. Cardiologists interpreting THI echocardiograms should become familiar with the modality's shortcomings. [source] EFFECT OF PARAPROSTHETIC MODERETE TO SEVERE MITRAL REGURGITATION ON EMBOLIC EVENTS IN PATIENTS WITH PROSTHETIC MITRAL VALVESECHOCARDIOGRAPHY, Issue 5 2004C. Cevik Thromboembolism is the major chronic risk for patients with mechanical prosthetic heart valves. Although optimal oral anticoagulantion is the key determinant for embolic events (EE) in these patients; other factors also contribute to this complication. We studied the prevalence and determinants of embolic events in patients with mitral prosthetic heart valves undergoing transesophageal echocardiography (TEE). 210 patients (86 male and 124 female, mean age 45.1 +/, 9.6 years) underwent a TEE study for evaluation of prosthetic valve functions. Clinical and TEE findings of the patients were as follows: Atrial fibrillation in 132 (%62) patients, prosthetic valve thrombus in 55 (%26) suboptimal INR (INR < 1.8) in 61 (%29) pts, left atrial spontenous echocardiographic contrast (SEC) in 31 (%14) patients, paraprosthetic moderete-severe mitral regurgitation (MR) in 28 (%13), left atrial (LA) and/or left atrial appendix (LAA) thrombus in 41 (%19), LA and/or LAA outflow velocities <0.25 m/sn in 21 patiens (%10), left atrial diameter >6 cm in 47 (%22). 72 patients had a history of EE in the previous 6 months (%34). In no patients were there any EE in the presence of paraprosthetic moderate to severe MR. Both with univariate and multivariate analysis presence of prosthetic valve and LA and/or LAA thrombus, absence of paraprosthetic moderete-severe MR, suboptimal INR, atrial fibrillation were found to be independent predictors for embolic events. Conclusions: Although the presence of prosthetic valve and LA and/or LAA thrombus, suboptimal INR, and AF predict EE, clinical and echocardiographic data support the protective effect of paraprosthetic moderate to severe MR against EE in pts with mitral prosthetic valves. [source] Purification of Matrix Gla Protein From a Marine Teleost Fish, Argyrosomus regius: Calcified Cartilage and Not Bone as the Primary Site of MGP Accumulation in Fish,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003DC Simes Abstract Matrix Gla protein (MGP) belongs to the family of vitamin K-dependent, Gla-containing proteins, and in mammals, birds, and Xenopus, its mRNA was previously detected in extracts of bone, cartilage, and soft tissues (mainly heart and kidney), whereas the protein was found to accumulate mainly in bone. However, at that time, it was not evaluated if this accumulation originated from protein synthesized in cartilage or in bone cells because both coexist in skeletal structures of higher vertebrates and Xenopus. Later reports showed that MGP also accumulated in costal calcified cartilage as well as at sites of heart valves and arterial calcification. Interestingly, MGP was also found to accumulate in vertebra of shark, a cartilaginous fish. However, to date, no information is available on sites of MGP expression or accumulation in teleost fishes, the ancestors of terrestrial vertebrates, who have in their skeleton mineralized structures with both bone and calcified cartilage. To analyze MGP structure and function in bony fish, MGP was acid-extracted from the mineralized matrix of either bone tissue (vertebra) or calcified cartilage (branchial arches) from the bony fish, Argyrosomus regius,, separated from the mineral phase by dialysis, and purified by Sephacryl S-100 chromatography. No MGP was recovered from bone tissue, whereas a protein peak corresponding to the MGP position in this type of gel filtration was obtained from an extract of branchial arches, rich in calcified cartilage. MGP was identified by N-terminal amino acid sequence analysis, and the resulting protein sequence was used to design specific oligonucleotides suitable to amplify the corresponding DNA by a mixture of reverse transcription-polymerase chain reaction (RT-PCR) and 5,rapid amplification of cDNA (RACE)-PCR. In parallel, ArBGP (bone Gla protein, osteocalcin) was also identified in the same fish, and its complementary DNA cloned by an identical procedure. Tissue distribution/accumulation was analyzed by Northern blot, in situ hybridization, and immunohistochemistry. In mineralized tissues, the MGP gene was predominantly expressed in cartilage from branchial arches, with no expression detected in the different types of bone analyzed, whereas BGP mRNA was located in bone tissue as expected. Accordingly, the MGP protein was found to accumulate, by immunohistochemical analysis, mainly in the extracellular matrix of calcified cartilage. In soft tissues, MGP mRNA was mainly expressed in heart but in situ hybridization, indicated that cells expressing the MGP gene were located in the bulbus arteriosus and aortic wall, rich in smooth muscle and endothelial cells, whereas no expression was detected in the striated muscle myocardial fibers of the ventricle. These results show that in marine teleost fish, as in mammals, the MGP gene is expressed in cartilage, heart, and kidney tissues, but in contrast with results obtained in Xenopus and higher vertebrates, the protein does not accumulate in vertebra of non-osteocytic teleost fish, but only in calcified cartilage. In addition, our results also indicate that the presence of MGP mRNA in heart tissue is due, at least in fish, to the expression of the MGP gene in only two specific cell types, smooth muscle and endothelial cells, whereas no expression was found in the striated muscle fibers of the ventricle. In light of these results and recent information on expression of MGP gene in these same cell types in mammalian aorta, it is likely that the levels of MGP mRNA previously detected in Xenopus, birds, and mammalian heart tissue may be restricted toregions rich in smooth muscle and endothelial cells. Our results also emphasize the need to re-evaluate which cell types are involved in MGP gene expression in other soft tissues and bring further evidence that fish are a valuable model system to study MGP gene expression and regulation. [source] Distribution of Porphyromonas gingivalis fimA genotypes in cardiovascular specimens from Japanese patientsMOLECULAR ORAL MICROBIOLOGY, Issue 2 2008K. Nakano Introduction:,Porphyromonas gingivalis, a major periodontal pathogen, is gaining increasing attention for its possible association with cardiovascular diseases. Its fimbriae are classified into six genotypes (types I,V and Ib) based on the diversity of the fimA genes encoding the fimbrial subunits. In this study, fimA genotypic distribution was analyzed in P. gingivalis -infected cardiovascular specimens. Methods:, A total of 112 heart valves and 80 atheromatous plaque specimens were collected from patients undergoing cardiovascular surgery, as well as 56 dental plaque specimens. Bacterial DNA was extracted from each, and polymerase chain reaction analysis was carried out with a P. gingivalis -specific set of primers. P. gingivalis- positive specimens were further analyzed to discriminate the fimA genotype using polymerase chain reaction with fimA type-specific primer sets. Results:,P. gingivalis was detected in 10.4% of the cardiovascular specimens and 50.0% of the dental plaque samples. In the latter, type II was most frequently detected (35.7%), followed by types I (28.6%) and IV (21.4%), while types IV and II were detected with considerable frequencies of 45.0% and 30.0%, respectively, in the cardiovascular specimens. In contrast, the occurrence of type I was limited (5.0%) in the cardiovascular specimens. Conclusion:, These results suggest that specific fimA genotypic clones, which are reportedly associated with periodontitis, are also frequently harbored in cardiovascular specimens, indicating the possible involvement of type II and IV clones in the initiation and progression of cardiovascular diseases. [source] Cardiac and noncardiac fibrotic reactions caused by ergot-and nonergot-derived dopamine agonists,MOVEMENT DISORDERS, Issue 1 2009Frank Andersohn MD Abstract There is growing evidence that the ergot-derived dopamine agonists cabergoline and pergolide can cause fibrotic cardiac valvulopathy. Data on other fibrotic reactions and nonergot-derived dopamine agonists are sparse. Aim of this study was to investigate whether there are signals that dopamine agonists are related to cardiac and other fibrotic reactions. We identified all reports of fibrotic reactions at the heart, lung, and retroperitoneal space associated with dopamine agonists within the US Adverse Event Reporting System database. Disproportionality analyses were used to calculate adjusted reporting odds ratios (RORs). For ergot-derived dopamine agonists (bromocriptine, cabergoline, pergolide), the RORs of all reactions under study were increased, whereas no such increases were observed for nonergot-derived drugs (apomorphine, pramipexole, ropinirole, rotigotine). Fibrotic reactions due to ergot-derived dopamine agonists may not be limited to heart valves. For nonergot-derived dopamine agonists, no drug safety signals were evident. © 2008 Movement Disorder Society [source] Differential protein expression between normal, early-stage, and late-stage myxomatous mitral valves from dogsPROTEOMICS - CLINICAL APPLICATIONS, Issue 12 2009Carla M. R. Lacerda Abstract Valvular heart disease accounts for over 20,000 deaths and 90,000 hospitalizations yearly in the United States. Myxomatous valve disease (MVD) is the most common disease of the mitral valve in humans and dogs. MVD is pathologically identical in these species and its pathogenesis is poorly understood. The objectives of this study were to (i) develop proteomic methodology suitable for analysis of extracellular matrix-rich heart valve tissues and (ii) survey over- and under-expressed proteins that could provide mechanistic clues into the pathogenesis of MVD. Normal, early-stage, and late-stage myxomatous mitral valves from dogs were studied. A shotgun proteomic analysis was used to quantify differential protein expression. Proteins were classified by function and clustered according to differential expression patterns. More than 300 proteins, with 117 of those being differentially expressed, were identified. Hierarchical sample clustering of differential protein profiles showed that early- and late-stage valves were closely related. This finding suggests that proteome changes occur in early degeneration stages and these persist in late stages, characterizing a diseased proteome that is distinct from normal. Shotgun proteome analysis of matrix-rich canine heart valves is feasible, and should be applicable to human heart valves. This study provides a basis for future investigations into the pathogenesis of MVD. [source] Natural and Prosthetic Heart Valve Calcification: Morphology and Chemical Composition CharacterizationARTIFICIAL ORGANS, Issue 4 2010Raquel F. Weska Abstract Calcification is the most common cause of damage and subsequent failure of heart valves. Although it is a common phenomenon, little is known about it, and less about the inorganic phase obtained from this type of calcification. This article describes the scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy and Ca K -edge X-ray absorption near edge structure (XANES) characterization performed in natural and bioprosthetic heart valves calcified in vivo (in comparison to in vitro-calcified valves). SEM micrographs indicated the presence of deposits of similar morphology, and XANES results indicate, at a molecular level, that the calcification mechanism of both types of valves are probably similar, resulting in formation of poorly crystalline hydroxyapatite deposits, with Ca/P ratios that increase with time, depending on the maturation state. These findings may contribute to the search for long-term efficient anticalcification treatments. [source] Aging Adversely Impacts Biological Properties of Human Bone Marrow-derived Mesenchymal Stem Cells: Implications for Tissue Engineering Heart Valve ConstructionARTIFICIAL ORGANS, Issue 3 2010Yuan Xin Abstract Our aim was to study the aging effects on the in vitro biological properties of bone marrow-derived mesenchymal stem cells (BMSCs) for construction of tissue-engineered heart valves. BMSCs were taken from teenagers with congenital heart diseases, and middle-aged and elderly patients with valvular diseases. Proliferative abilities were compared among the three groups by using colony-forming unit counting and growth curves (5-bromo-2,-deoxyuridine assay). Cell differentiation, vascular endothelial growth factor (VEGF) release under hypoxic condition, and migratory abilities were compared as well. Colony-forming units in the teenage group were significantly greater than those in the other two groups (P < 0.05), and significantly higher counts were observed in the middle age group than in the aged group (P < 0.05). Growth curves presented similar trends in which cells' proliferative abilities in the aged group decreased significantly (P < 0.05), while no differences were noted between the two nonaged groups. The differentiation potential to endothelial cells, osteoblasts and adipocytes, VEGF releases, and migratory abilities differed significantly between the aged group and nonaged groups (P < 0.05). However, no differences were noted between the two nonaged groups. BMSCs from older patients with heart valve diseases could be harvested and expanded successfully, and the phenotype and morphology were uniform as nonaged groups. However, the proliferative and differentiation properties of aged cells, as well as cytokine release and migratory abilities, are significantly impaired. [source] Fabrication of a Novel Hybrid Heart Valve Leaflet for Tissue Engineering: An In Vitro StudyARTIFICIAL ORGANS, Issue 7 2009Hao Hong Abstract The objective of this study was to fabricate biomatrix/polymer hybrid heart valve leaflet scaffolds using an electrospinning technique and seeded by mesenchymal stem cells. Mesenchymal stem cells were obtained from rats. Porcine aortic heart valve leaflets were decellularized, coated with basic fibroblast growth factor/chitosan/poly-4-hydroxybutyrate using an electrospinning technique, reseeded, and cultured over a time period of 14 days. Controls were reseeded and cultured over an equivalent time period. Specimens were examined biochemically, histologically, and mechanically. Recellularization of the hybrid heart valve leaflet scaffolds was significantly improved compared to controls. Biochemical and mechanical analysis revealed a significant increase of cell mass, 4-hydroxyproline, collagen, and strength in the hybrid heart valve leaflets compared to controls. This is the first attempt in tissue-engineered heart valves to fabricate hybrid heart valve leaflets using mesenchymal stem cells combined with a slow release technique and an electrospinning technique. [source] Prospects in Lyophilization of Bovine PericardiumARTIFICIAL ORGANS, Issue 3 2009Adolfo A. Leirner Abstract Almost 30 years after the introduction of heart valve prostheses patients worldwide are benefiting from the implant of these devices. Among the various types of heart valves, the ones made of treated bovine pericardium have become a frequently used replacement of the heart's native valve. Lyophilization, also known as freeze-drying, is an extremely useful technique for tissue storage for surgical applications. This article gives a brief overview on the current bovine pericardium lyophilization development, including the chemical modification to improve physical,chemical characteristics and the advanced technologies used to guarantee a high-quality product. It was shown that lyophilization process can be successfully applied as a method of bovine pericardium preservation and also as a technological tool to prepare new materials obtained by chemical modification of native tissues. [source] Tissue Engineering of Heart Valves In Vivo Using Bone Marrow-derived CellsARTIFICIAL ORGANS, Issue 7 2006Sang-Soo Kim Abstract:, In this study, we tissue-engineered heart valves in vivo using autologous bone marrow-derived cells (BMCs). Canine BMCs were differentiated into endothelial cell (EC)-like cells and myofibroblast (MF)-like cells. Decellularized porcine pulmonary valves were seeded with BMCs and implanted to abdominal aorta and pulmonary valve of bone marrow donor dogs. Histological examination of the explants identified the regeneration of valvular structures expressing CD31 and smooth muscle ,-actin, indicating the presence of EC-like and MF-like cells in the grafts at 3 and 1 week, respectively, after implantation. Fluorescent microscopic examinations identified the presence of fluorescently labeled cells in the explants, indicating that the implanted BMCs survived and participated in the heart valve reconstitution. This study reports, for the first time, on tissue engineering of heart valve in vivo using BMCs. [source] The Complexity of External Acoustic Detection of Defects in Björk-Shiley Convexoconcave Heart ValvesARTIFICIAL ORGANS, Issue 1 2001Bas A. De Mol Abstract: Fractures in Björk-Shiley convexoconcave (BScc) heart valves have raised questions about the feasibility of early diagnosis of technical defects by means of acoustic assessment. Three laboratory tests were conducted. To establish acoustic fingerprints, 66 valves with a defect, such as single-leg fracture (SLF) or single-leg separation (SLS), or without a defect were connected with a contact sensor and excited by dropping a small metal ball onto the outlet strut. In the second test, we simulated the valve sound propagation within the thorax. In the third test, intact, SLF, and SLS valves were placed in a mock heart immersed in a large water tank. We observed a resonance frequency corresponding with valve size and presence of defects. The second test showed that both the chest wall and the lungs created numerous reflections. This led to a substantial overlap of the original pulse frequencies and the frequencies measured. The third test confirmed that submersion of the chest in water can significantly reduce chest wall reflections. Reliable noninvasive assessment of BScc valve clicks for the presence of defects of the outlet strut is hampered by complex sound propagation within the thorax and variability of valve excitation. Acoustic fingerprints to diagnose mechanical defects should be integrated in valve design. [source] A Novel In Vitro Assessment of Tissue Valve Calcification by a Continuous Flow Type MethodARTIFICIAL ORGANS, Issue 2 2000Jong-Chul Park Abstract: A dynamic flow type testing to study calcification was self-designed to investigate calcification in bioprosthetic heart valves. The apparatus consists of a container into which leaflets from a porcine aortic valve are placed, a chamber that contains calcium solution, and a peristaltic pump that provides a continuous supply of the solution toward the container. Efficacy of the apparatus was compared with the conventional batch type calcification testing at 37°C through measuring the amount of calcium and phosphate deposited by inductively coupled plasma (ICP) and scanning electron microscope (SEM). After 14 days, calcium levels detected from the calcified deposit on leaflets were 470.4 ± 37.0 ,g/cm3 in the flow type testing whereas in the batch type testing levels were 81.0 ± 6.7 ,g/cm3. Though the calcium level on the leaflet increased as the exposure time to calcium solution increased in both testings, the rate and the tendency of calcification could be assessed very rapidly by flow type testing in comparison with batch type testing. [Ca]/[P] molar ratio decreased over time, and after 14 days, the ratio was close to 1.83 ± 0.18 in the flow type testing. The ratio could not be determined in the batch type testing because the deposit was too small to assess. The descending rate of [Ca]/[P] molar ratio demonstrates that deposited calcium-complex at the earliest stage may interact with inorganic phosphate ions to create a calcified deposit mineral precursor. This in vitro dynamic flow type calcification testing was a favorable tool for rapid investigation of calcification. [source] Maternal complications and pregnancy outcome in women with mechanical prosthetic heart valves treated with enoxaparinBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 12 2009C McLintock Objective, To determine maternal and fetal outcomes in women with mechanical heart valves managed with therapeutic dose enoxaparin during pregnancy. Design, Retrospective audit. Setting, Hospital-based high-risk antenatal clinics. Population, Pregnant women with mechanical heart valves attending high-risk antenatal clinics, treated with enoxaparin (1 mg/kg twice daily) during pregnancy. Methods, Women with mechanical heart valves treated with enoxaparin at any stage during pregnancy (1997,2008) identified using a database of women with mechanical heart valves attending the high-risk clinics and a prospective database of women prescribed enoxaparin for any indication during pregnancy. Main outcome measures, Maternal outcomes included thromboembolic and haemorrhagic complications. Pregnancy and fetal outcomes included miscarriage, stillbirth, baby death and live birth, small-for-gestational-age infants, warfarin embryopathy and warfarin-related fetal loss. Results, Thirty-one women underwent 47 pregnancies. In 34 pregnancies (72.3%), anticoagulation was with predominantly enoxaparin and 13 (27.7%) pregnancies women received mainly warfarin, with enoxaparin given in the first trimester and/or peri-delivery. Seven (14.9%) thrombotic complications occurred, of which five (10.6%) were associated with enoxaparin treatment. Non-compliance or sub-therapeutic anti-Xa levels contributed in each case. Antenatal and postpartum haemorrhagic complications occurred in eight (17%) and 15 (32%) pregnancies respectively. Of 35 pregnancies continuing after 20 weeks' gestation, 96% (22/23) of women taking predominantly enoxaparin had a surviving infant compared with 75% (9/12) in women taking primarily warfarin. Four perinatal deaths occurred, three attributable to warfarin. Conclusions, Compliance with therapeutic dose enoxaparin and aspirin during pregnancy in women with mechanical heart valves is associated with a low risk of valve thrombosis and good fetal outcomes, but close monitoring is essential. [source] Endocarditis due to Tropheryma whipplei: rapid detection, limited genetic diversity, and long-term clinical outcome in a local experienceCLINICAL MICROBIOLOGY AND INFECTION, Issue 8 2010R. Escher Clin Microbiol Infect 2010; 16: 1213,1222 Abstract The characteristic features of Whipple's disease include abdominal pain, diarrhoea, wasting, and arthralgias, with the causative agent, Tropheryma whipplei, being detected mainly in intestinal biopsies. PCR technology has led to the identification of T. whipplei in specimens from various other locations, including the central nervous system and the heart. T. whipplei is now recognized as one of the causes of culture-negative endocarditis, and endocarditis can be the only manifestation of the infection with T. whipplei. Although it is considered a rare disease, the true incidence of endocarditis due to T. whipplei is not clearly established. With the increasing use of molecular methods, it is likely that T. whipplei will be more frequently identified. Questions also remain about the genetic variability of T. whipplei strains, optimal diagnostic procedures and therapeutic options. In the present study, we provide clinical data on four new patients with documented endocarditis due to T. whipplei in the context of the available published literature. There was no clinical involvement of the gastrointestinal tract. Genetic analysis of the T. whipplei strains with DNA isolated from the excised heart valves revealed little to no genetic variability. In a selected case, we describe acridine orange staining for early detection of the disease, prompting early adaptation of the antibiotic therapy. We provide long-term follow-up data on the patients. In our hands, an initial 2-week course of intravenous antibiotics followed by cotrimoxazole for at least 1 year was a suitable treatment option for T. whipplei endocarditis. [source] | |||||||||||||