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1.
Artif Organs ; 43(10): 976-987, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31140630

RESUMO

Transcatheter aortic valve implantation (TAVI) has gained considerable acceptance in the past decade due to its lower risks than conventional open-heart surgery. However, the deformation and delamination of the leaflets during the crimping procedure have raised questions about the durability and long-term serviceability of the pericardium tissue from which the leaflets are made. The collagen architecture, wall thickness and mechanical properties of donkey pericardium were investigated to assess its suitability as an alternative material for the manufacture of heart valves. Coupons sampled from different locations of donkey pericardium were investigated. Bovine, equine, and porcine pericardium specimens served as controls. The donkey pericardium had a similar surface morphology to that of the control pericardia except for the wavy topology on both the fibrous and serous sides. The average thickness of donkey pericardium (ca. 120 µm) was significantly lower than that from bovine (375 µm) and equine (410 µm), but slightly higher than that from porcine (99 µm) specimens. The interlaced wavy collagen bundles in the pericardium were composed of collagen fibers about 100 nm in diameter. This unique structure ensures that the donkey pericardium has a comparable ultimate tensile strength (UTS) and a much higher failure strain than the commercial pericardia used for the manufacture of heart valves. The donkey pericardium has an organized wavy collagen bundle architecture similar to that of bovine pericardium and has a satisfactory UTS and high failure strain. The thin and strong donkey pericardium might be a good candidate valve leaflet material for TAVI.


Assuntos
Materiais Biocompatíveis/química , Bioprótese , Colágeno/análise , Próteses Valvulares Cardíacas , Pericárdio/química , Animais , Valva Aórtica/cirurgia , Fenômenos Biomecânicos , Bovinos , Elasticidade , Equidae , Valvas Cardíacas/cirurgia , Cavalos , Teste de Materiais , Pericárdio/ultraestrutura , Suínos , Resistência à Tração , Substituição da Valva Aórtica Transcateter
2.
Morphologie ; 103(341): 37-47, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30638803

RESUMO

BACKGROUND: The kangaroo pericardium might be considered to be a good candidate material for use in the manufacture of the leaflets of percutaneous heart valves based upon the unique lifestyle. The diet consists of herbs, forbs and strubs. The kangaroo pericardium holds an undulated structure of collagen. MATERIAL AND METHOD: A Red Kangaroo was obtained after a traffic fatality and the pericardium was dissected. Four compasses were cut from four different sites: auricular (AUR), atrial (ATR), sternoperitoneal (SPL) and phrenopericardial (PPL). They were investigated by means of scanning electron microscopy, light microscopy and transmission electron microscopy. RESULTS: All the samples showed dense and wavy collagen bundles without vascularisation from both the epicardium and the parietal pericardium. The AUR and the ATR were 150±25µm thick whereas the SPL and the PPL were thinner at 120±20µm. The surface of the epicardium was smooth and glistening. The filaments of collagen were well individualized without any aggregation, but the banding was poorly defined and somewhat blurry. CONCLUSION: This detailed morphological analysis of the kangaroo pericardium illustrated a surface resistant to thrombosis and physical characteristics resistant to fatigue. The morphological characteristics of the kangaroo pericardium indicate that it represents an outstanding alternative to the current sources e.g., bovine and porcine. However, procurement of tissues from the wild raises supply and sanitary issues. Health concerns based upon sanitary uncertainty and reliability of supply of wild animals remain real problems.


Assuntos
Bioprótese , Próteses Valvulares Cardíacas , Ligamentos/ultraestrutura , Macropodidae/anatomia & histologia , Pericárdio/ultraestrutura , Animais , Austrália , Doenças das Valvas Cardíacas/cirurgia , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão
3.
J Biomater Appl ; 33(5): 637-646, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30335541

RESUMO

Valvular heart diseases lead to over 300,000 heart valve replacements worldwide each year. Commercially available bioprosthetic heart valves (BHVs) are mostly made from porcine or bovine pericardiums which were crosslinked by glutaraldehyde (GLUT). However, valve failures can occur within 10 years due to progressive degradation and calcification. GLUT could crosslink collagen but it fails to stabilize elastin. In this current study, we developed a new BHVs preparation strategy named as "GLUT/TE/LOXL/EGCG" that utilizes exogenous tropoelastin (TE)/lysyl oxidase (LOXL) and epigallocatechin gallate (EGCG) to increase the elastin content as well as the stabilization of elastin. The feeding ratios of tropoelastin and lysyl oxidase were optimized. The contents of desmosine and insoluble elastin, biomechanics, cytotoxicity, hemocompatibility, in vivo componential stability and anti-calcification potential were characterized. Pericardiums with increased elastin content had improved the mechanical properties. GLUT/TE/LOXL/EGCG-treated pericardiums had similar cytotoxicity and coagulation properties compared to GLUT and GLUT/EGCG control. We demonstrated that GLUT/TE/LOXL/EGCG-treated pericardiums had high amount of insoluble elastin in 90 days' rat subdermal implantation model, and better resistance for calcification. This new tropoelastin and lysyl oxidase treatments strategy would be a promising method to make BHVs which have better structural stability and anti-calcification properties.


Assuntos
Bioprótese , Elastina/química , Próteses Valvulares Cardíacas , Pericárdio/química , Animais , Fenômenos Biomecânicos , Bioprótese/efeitos adversos , Calcinose/etiologia , Catequina/análogos & derivados , Catequina/química , Reagentes para Ligações Cruzadas/química , Glutaral/química , Próteses Valvulares Cardíacas/efeitos adversos , Masculino , Pericárdio/transplante , Pericárdio/ultraestrutura , Estabilidade Proteica , Proteína-Lisina 6-Oxidase/química , Ratos Sprague-Dawley , Suínos , Tropoelastina/química
4.
Adv Exp Med Biol ; 1098: 115-130, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30238368

RESUMO

Tissue engineering and regenerative medicine have adopted the use of extracellular matrix (ECM) as a cell delivery device and bioactive regenerative agent. To this end, many ECMs have been investigated for cardiac tissue engineering and regenerative medicine applications with variable success. Many sources of natural ECMs have been tested for cardiac applications. Typically, natural ECMs have been made from decellularized organs or tissues and processed into either sheets or injectable hydrogels. This chapter will review natural sources of ECM materials that have been tested as therapeutic agents in models of heart failure.


Assuntos
Procedimentos Cirúrgicos Cardíacos/métodos , Matriz Extracelular , Insuficiência Cardíaca/cirurgia , Medicina Regenerativa/métodos , Tecidos Suporte , Animais , Processos de Crescimento Celular , Matriz Extracelular/fisiologia , Previsões , Humanos , Intestino Delgado/ultraestrutura , Camundongos , Modelos Animais , Miocárdio/ultraestrutura , Especificidade de Órgãos , Pericárdio/ultraestrutura , Coelhos , Especificidade da Espécie , Transplante de Células-Tronco/métodos , Suínos , Bexiga Urinária/ultraestrutura , Peixe-Zebra
5.
Artif Organs ; 42(11): 1062-1069, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30058211

RESUMO

The lifetime of bioprosthetic heart valves (BHVs) is limited by the mechanical damage and calcification. The major components of BHVs are collagen and elastin. Collagen could be well protected by glutaraldehyde (GLUT) crosslinking, while elastin is not stabilized and has a high risk of degradation, which could lead to the calcification of BHVs. We aimed to develop methods for stabilizing elastin and decreasing calcification. We investigated the combined tannic acid (TA) or epigallocatechin gallate (EGCG) with ferric chloride to stabilize elastin and prevent calcification. We found that the amount of TA/EGCG bound to elastin was in a time-dependent pattern and this reaction showed better efficiency in acidic condition and ethanol-water mixed solvents. Moreover, Fe3+ could compete with Ca2+ to bind to polyphenol, which could reduce the calcium deposition on BHVs. Cytotoxicity test showed that all extracts from different treatments had similar cell viabilities (85-100%). Through the combined treatments of polyphenol and ferric chloride, the pericardium had a better resistance to elastase degradation and more excellent anticalcification performance.


Assuntos
Bioprótese , Calcinose/prevenção & controle , Cloretos/química , Elastina/química , Compostos Férricos/química , Próteses Valvulares Cardíacas , Pericárdio/química , Polifenóis/química , Animais , Catequina/análogos & derivados , Catequina/química , Colágeno/química , Reagentes para Ligações Cruzadas/química , Glutaral/química , Masculino , Pericárdio/ultraestrutura , Estabilidade Proteica , Ratos Sprague-Dawley , Suínos , Taninos/química , Resistência à Tração
6.
Mech Ageing Dev ; 173: 9-20, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29702130

RESUMO

Here we show that a labyrinth channel compartment and slit diaphragms, which are the histological structures enabling insect nephrocytes ultrafiltration, are established during embryogenesis first by the garland nephrocytes (GCNs). The later pericardial nephrocytes, which represent the majority of functional nephrocytes in larvae and adults, lack these characteristic features at the embryonic stage. During larval development, a subpopulation of the pericardial cells survives and matures into functional nephrocytes (PCNs) displaying a fully differentiated slit diaphragm and a labyrinth channel compartment. Likely the embryonic pericardial cells have primary functions other than ultrafiltration (e.g. in production and secretion of ECM constituents). We also show, for the first time, that PCNs in the adult fly undergo dramatic histological degeneration upon ageing. The slit diaphragms disappear, the labyrinth channel system degenerates and the lysosomal compartment becomes highly enriched with electron-dense material. When using nephrocytes as a model for genetic screening purposes or to investigate the specific role of genes involved in endocytosis, histological changes occurring upon ageing need to be taken into account when interpreting structural data.


Assuntos
Envelhecimento/patologia , Endocitose , Lisossomos/ultraestrutura , Pericárdio/ultraestrutura , Envelhecimento/metabolismo , Animais , Drosophila melanogaster , Lisossomos/metabolismo , Pericárdio/metabolismo
7.
Artif Organs ; 42(5): 540-548, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29280157

RESUMO

Bovine and porcine pericardia are currently used for manufacturing prosthetic heart valves: their design has become an increasingly important area of investigation in parallel with progressively expanding indications for the transcutaneous approach to heart valves replacement. Before being cut and shaped, pericardial tissues are expected to be properly characterized. Actually, the mechanical assessment of these biomaterials lacks standardized protocols. In particular, the role of preconditioning for achieving a constant mechanical response of tissue samples is still controversial. In the present work, the mechanical response to uniaxial load of native bovine and porcine pericardia, with and without preconditioning was assessed; moreover, the mechanical behavior of pericardia was investigated and explained. It was demonstrated that: (i) pericardial tissue samples hold memory of the loading history but just within the extent of the deformation applied; (ii) the behavior of native bovine and porcine pericardia in response to load is explained by a mechanism based on the additive recruitment of collagen fibers; (iii) the current concept that plasticity is absent in pericardium has to be at least in part reconsidered.


Assuntos
Colágeno/análise , Pericárdio/fisiologia , Pericárdio/ultraestrutura , Animais , Fenômenos Biomecânicos , Bioprótese , Bovinos , Colágeno/metabolismo , Próteses Valvulares Cardíacas , Teste de Materiais , Pericárdio/química , Suínos , Resistência à Tração , Suporte de Carga
8.
Morphologie ; 101(333): 77-87, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28442174

RESUMO

INTRODUCTION: Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis. MATERIAL AND METHOD: Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures. A pericardial patch embossed to provide the adequate shape of the cusps was investigated after paraffin embedding and appropriate staining. The microstructural damages that occurred during manufacturing process were identified and evaluated by light microscopy, polarized microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: The wavy collagen bundles, the key structure of the pericardium patch, were damaged to a great extent at suture sites along the stent and in the compressed areas around the stent post. The fixation of the embossed pericardium patch along the plots of the stent aggravated the microstructural modifications. The damages mainly appeared as the elimination of collagen bundle waviness and delamination between the bundles. CONCLUSION: Considering the modes of failure of the explant, the damages to the collagen bundles may identify the vulnerable sites that play an important role in the cusp dehiscence of heart valve implants. Such information is important to the manufacturers. Recommendations to prevent in vivo cusp dehiscence can therefore be formulated.


Assuntos
Valva Aórtica/ultraestrutura , Bioprótese , Próteses Valvulares Cardíacas , Pericárdio/ultraestrutura , Manejo de Espécimes/efeitos adversos , Animais , Valva Aórtica/patologia , Calcinose/prevenção & controle , Bovinos , Colágeno/ultraestrutura , Reagentes para Ligações Cruzadas/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Inclusão em Parafina , Pericárdio/anatomia & histologia , Pericárdio/patologia , Inclusão em Plástico/métodos , Polimetil Metacrilato/química , Falha de Prótese , Manejo de Espécimes/métodos , Stents
9.
Morphologie ; 101(332): 19-32, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27423215

RESUMO

INTRODUCTION: Transcathether heart valve replacement has gained considerable acceptance during the last decades. It is now part of the armamentarium for aortic valve replacement. The procedure proved to be highly efficient. However the issues of the blood compatibility and tissue durability were not raised and the adverse events were probably under-reported, according to observations of thrombosis after deployment. MATERIAL AND METHOD: Bovine pericardium leaflets were sewn inside a 26mm diameter stainless steel stent to manufacture these valves (one control and two experimental). The correlation between the trauma and the acute thombogenicity of bovine pericardium leaflets, after crimping and ballooning, was investigated via an in vitro blood flow with labeled platelets. These leaflets were processed for histology: scanning electron microscopy, light microscopy, and transmission electron microscopy. RESULTS: The control specimens showed a regular pericardium structure with some blood cells deposited on the collagen fibrous surface (inflow) and scarce blood cells deposited on the serous surface (outflow). After crimping and ballooning, the structure of the pericardium was severely injured, eventually with delaminations and ruptures. The blood cell uptake was considerably increased compared to the control. CONCLUSION: It would therefore be appropriate to pay more attention to the design of the valves. Specifically, the incorporation of a buffer tissue or fabric between the pericardium and the metallic stent is suggested. The issue of ballooning deserves detailed and in depth investigation regarding the lifetime of the device.


Assuntos
Valvuloplastia com Balão/instrumentação , Bioprótese/efeitos adversos , Próteses Valvulares Cardíacas/efeitos adversos , Desenho de Prótese/efeitos adversos , Trombose/etiologia , Substituição da Valva Aórtica Transcateter/instrumentação , Animais , Valva Aórtica/cirurgia , Circulação Sanguínea , Bovinos , Voluntários Saudáveis , Humanos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Pericárdio/patologia , Pericárdio/cirurgia , Pericárdio/ultraestrutura , Stents/efeitos adversos , Propriedades de Superfície , Trombose/prevenção & controle , Substituição da Valva Aórtica Transcateter/efeitos adversos
10.
Vnitr Lek ; 62(4): 256-62, 2016 Apr.
Artigo em Tcheco | MEDLINE | ID: mdl-27250602

RESUMO

BACKGROUND: To assess the relationship of parameters of obesity in relationship to coronary angiography findings with correlation of epicardial fat (EF) thickness in uppermentioned context. METHODS: There were 80 patients examined (43 males, 37 postmenopausal females) undergoing elective coronary angiography. We examined the regular obesity parameters - BMI, waist circumference (WC), neck circumference (NC), total body fat (TBF), and visceral fat (VF) using bioimpedance. We assessed the echocardiographically measured EF thickness. We added examination of lipidogram, glycaemia, HOMA-IR (insulin resistance index) and AIP (aterogenic index of plasma). The set was divided into group with coronarographically proved stenosis or stenoses (withCS), and a group without finding of quantifiable stenosis or stenoses (withoutCS). RESULTS: The average thickness of EF in withCS group was 6.3 vs 5.6 mm in group withoutCS (p < 0.025). The differences in the thickness of EF in mentioned groups were 6.5 vs 5.2 mm in males (p < 0.025, = 20 %) and 6.1 vs 6.0 mm in females (p < 0.025, = 1.64 %). In males in withCS group, there was a dominant fat increase in epicardial region and TBF, and in females in withCS group, the fat deposits were increased in general. BMI was not a dominant parameter of adiposity in neither group (males in withCS group 31.11 vs withoutCS 30.41 kg/m(2); females in withCS group 31.40 vs withoutCS 31.20 kg/m(2)). EF was correlated the most by WC in males (r = 0.488; p < 0.005), and in females too (r = 0.564, p < 0.005). The patients in withCS group had increased HOMA-IR 4.75 vs 3.56 in withoutCS group, and AIP 0.22 vs 0.17. CONCLUSION: Thickness of EF in males and VT in females could be considered obesity parameters in assessment of pre-clinical stages of coronary atherosclerosis and prediction of risk of coronary heart disease. In adipose parameters, EF thickness was correlated the most by WC. Risk stratification of coronary artery disease is supplemented by increased HOMA-IR and AIP.


Assuntos
Tecido Adiposo/diagnóstico por imagem , Doença da Artéria Coronariana/diagnóstico por imagem , Obesidade/complicações , Pericárdio/ultraestrutura , Índice de Massa Corporal , Angiografia Coronária , Feminino , Humanos , Resistência à Insulina , Masculino , Pessoa de Meia-Idade , Medição de Risco , Ultrassonografia , Circunferência da Cintura
11.
J Mol Cell Cardiol ; 90: 139-45, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26686990

RESUMO

The transcription factor Wilms' Tumor-1 (WT1) is essential for cardiac development. Deletion of Wt1 in mice results in disturbed epicardial and myocardial formation and lack of cardiac vasculature, causing embryonic lethality. Little is known about the role of WT1 in the human fetal heart. Therefore, as a first step, we analyzed the expression pattern of WT1 protein during human cardiac development from week 4 till week 20. WT1 expression was apparent in epicardial, endothelial and endocardial cells in a spatiotemporal manner. The expression of WT1 follows a pattern starting at the epicardium and extending towards the lumen of the heart, with differences in timing and expression levels between the atria and ventricles. The expression of WT1 in cardiac arterial endothelial cells reduces in time, whereas WT1 expression in the endothelial cells of cardiac veins and capillaries remains present at all stages studied. This study provides for the first time a detailed description of the expression of WT1 protein during human cardiac development, which indicates an important role for WT1 also in human cardiogenesis.


Assuntos
Células Endoteliais/metabolismo , Coração Fetal/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Proteínas WT1/genética , Endocárdio/crescimento & desenvolvimento , Endocárdio/metabolismo , Endocárdio/ultraestrutura , Células Endoteliais/ultraestrutura , Endotélio Vascular/crescimento & desenvolvimento , Endotélio Vascular/metabolismo , Endotélio Vascular/ultraestrutura , Coração Fetal/crescimento & desenvolvimento , Coração Fetal/ultraestrutura , Feto , Humanos , Miocárdio/metabolismo , Miocárdio/ultraestrutura , Pericárdio/crescimento & desenvolvimento , Pericárdio/metabolismo , Pericárdio/ultraestrutura , Proteínas WT1/metabolismo
12.
Development ; 142(1): 21-30, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25516967

RESUMO

An important pool of cardiovascular progenitor cells arises from the epicardium, a single layer of mesothelium lining the heart. Epicardium-derived progenitor cell (EPDC) formation requires epithelial-to-mesenchymal transition (EMT) and the subsequent migration of these cells into the sub-epicardial space. Although some of the physiological signals that promote EMT are understood, the functional mediators of EPDC motility and differentiation are not known. Here, we identify a novel regulatory mechanism of EPDC mobilization. Myocardin-related transcription factor (MRTF)-A and MRTF-B (MKL1 and MKL2, respectively) are enriched in the perinuclear space of epicardial cells during development. Transforming growth factor (TGF)-ß signaling and disassembly of cell contacts leads to nuclear accumulation of MRTFs and the activation of the motile gene expression program. Conditional ablation of Mrtfa and Mrtfb specifically in the epicardium disrupts cell migration and leads to sub-epicardial hemorrhage, partially stemming from the depletion of coronary pericytes. Using lineage-tracing analyses, we demonstrate that sub-epicardial pericytes arise from EPDCs in a process that requires the MRTF-dependent motile gene expression program. These findings provide novel mechanisms linking EPDC motility and differentiation, shed light on the transcriptional control of coronary microvascular maturation and suggest novel therapeutic strategies to manipulate epicardium-derived progenitor cells for cardiac repair.


Assuntos
Movimento Celular , Vasos Coronários/crescimento & desenvolvimento , Pericárdio/citologia , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Animais , Células COS , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/metabolismo , Embrião de Mamíferos/efeitos dos fármacos , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/patologia , Camundongos Endogâmicos C57BL , Neovascularização Fisiológica/efeitos dos fármacos , Pericárdio/metabolismo , Pericárdio/ultraestrutura , Pericitos/citologia , Pericitos/efeitos dos fármacos , Fator de Resposta Sérica/metabolismo , Transativadores/genética , Fatores de Transcrição/genética , Fator de Crescimento Transformador beta1/farmacologia
13.
Biomed Res Int ; 2014: 189197, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25295250

RESUMO

Bovine pericardium is used for heart valve leaflet replacement where the strength and thinness are critical properties. Pericardium from neonatal animals (4-7 days old) is advantageously thinner and is considered as an alternative to that from adult animals. Here, the structures of adult and neonatal bovine pericardium tissues fixed with glutaraldehyde are characterized by synchrotron-based small angle X-ray scattering (SAXS) and compared with the mechanical properties of these materials. Significant differences are observed between adult and neonatal tissue. The glutaraldehyde fixed neonatal tissue has a higher modulus of elasticity (83.7 MPa) than adult pericardium (33.5 MPa) and a higher normalised ultimate tensile strength (32.9 MPa) than adult pericardium (19.1 MPa). Measured edge on to the tissue, the collagen in neonatal pericardium is significantly more aligned (orientation index (OI) 0.78) than that in adult pericardium (OI 0.62). There is no difference in the fibril diameter between neonatal and adult pericardium. It is shown that high alignment in the plane of the tissue provides the mechanism for the increased strength of the neonatal material. The superior strength of neonatal compared with adult tissue supports the use of neonatal bovine pericardium in heterografts.


Assuntos
Colágeno/metabolismo , Valvas Cardíacas/ultraestrutura , Pericárdio/ultraestrutura , Animais , Animais Recém-Nascidos , Procedimentos Cirúrgicos Cardíacos , Bovinos , Colágeno/ultraestrutura , Glutaral/química , Valvas Cardíacas/metabolismo , Valvas Cardíacas/transplante , Pericárdio/patologia , Pericárdio/transplante , Espalhamento a Baixo Ângulo , Fixação de Tecidos , Difração de Raios X
14.
Nutr Hosp ; 30(3): 609-13, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25238838

RESUMO

INTRODUCTION: The current study was designed to determine the effect of home-based treadmill training on epicardial and abdominal adipose tissue in postmenopausal women with metabolic syndrome (MS). A secondary objective was to identify significant correlations between imaging and conventional anthropometric parameters. MATERIAL AND METHODS: Sixty postmenopausal women with MS volunteered for the current trial. Thirty were randomly assigned to perform a supervised home-based 16-week treadmill training program, 3 sessions/week, consisting of a warm-up, 30-40 min treadmill exercise (increasing 5-minutes each 4-weeks) at a work intensity of 60-75% of peak heart rate (increasing 5% each 4-weeks) and cooling-down. Epicardial fat thickness (EFT) was assessed by echocardiography. Abdominal fat mass in the lumbar regions L1-L4 and L4-L5 was determined by dual X-ray absorptiometry. RESULTS: Epicardial fat thickness and abdominal fat percentages were significantly improved after the completion of the training program. Another striking feature of the current study was the moderate correlation that was found between EFT and waist circumference (WC). CONCLUSION: Home-based treadmill training reduced epicardial and abdominal fat in postmenopausal women with MS. A secondary finding was that a moderate correlation was found between EFT and WC. While current investigations are promising, future studies are still required to consolidate this approach in clinical application.


Assuntos
Gordura Abdominal , Terapia por Exercício , Síndrome Metabólica/terapia , Pericárdio , Gordura Abdominal/diagnóstico por imagem , Absorciometria de Fóton , Tecido Adiposo/diagnóstico por imagem , Índice de Massa Corporal , Feminino , Humanos , Pessoa de Meia-Idade , Pericárdio/ultraestrutura , Pós-Menopausa , Ultrassonografia , Circunferência da Cintura
15.
J Periodontal Res ; 49(4): 499-507, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24024647

RESUMO

BACKGROUND AND OBJECTIVE: To investigate the feasibility of acellular bovine pericardium (BP) for guided bone regeneration (GBR) in vitro and in vivo. The success of GBR relies on the fact that various cellular components possess different migration rates into the defect site and that a barrier membrane plays a significant role in these processes. MATERIAL AND METHODS: BP membrane was isolated and decellularized using an enzymatic method. The microarchitecture, mechanical properties, cytotoxicity and cell chemotaxis properties of the acellular BP were evaluated in vitro, and the in-vivo efficacy of the acellular BP was also investigated in a rabbit mandibular model. RESULTS: The acellular BP membrane possessed an interconnected fibrous structure. Glutaraldehyde (GA) treatment was efficient for enhancement of the mechanical properties of the acellular BP bur and resulted in negligible cytotoxicity. After 16 wk, standardized osseous defects created in the rabbit mandible, and covered with acellular BP, were associated with an enhanced deposition of mineralized tissue when compared with defects left to spontaneous healing. CONCLUSION: GA-treated acellular BP is promising as a barrier membrane for GBR for further in-vivo and clinical studies.


Assuntos
Regeneração Tecidual Guiada/métodos , Membranas Artificiais , Pericárdio , Células 3T3 , Absorciometria de Fóton , Animais , Materiais Biocompatíveis/química , Bioprótese , Densidade Óssea/fisiologia , Calcificação Fisiológica/fisiologia , Bovinos , Quimiotaxia/fisiologia , Modelos Animais de Doenças , Estudos de Viabilidade , Doenças Mandibulares/cirurgia , Camundongos , Pericárdio/química , Pericárdio/ultraestrutura , Coelhos , Estresse Mecânico , Propriedades de Superfície , Temperatura , Resistência à Tração , Preservação de Tecido/métodos
16.
Dev Biol ; 383(2): 307-20, 2013 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-24016759

RESUMO

The epicardium and coronary vessels originate from progenitor cells in the proepicardium. Here we show that Tbx18, a T-box family member highly expressed in the proepicardium, controls critical early steps in coronary development. In Tbx18(-/-) mouse embryos, both the epicardium and coronary vessels exhibit structural and functional defects. At E12.5, the Tbx18-deficient epicardium contains protrusions and cyst-like structures overlying a disorganized coronary vascular plexus that contains ectopic structures resembling blood islands. At E13.5, the left and right coronary stems form correctly in mutant hearts. However, analysis of PECAM-1 whole mount immunostaining, distribution of SM22α(lacZ/+) activity, and analysis of coronary vascular casts suggest that defective vascular plexus remodeling produces a compromised arterial network at birth consisting of fewer distributing conduit arteries with smaller lumens and a reduced capacity to conduct blood flow. Gene expression profiles of Tbx18(-/-) hearts at E12.5 reveal altered expression of 79 genes that are associated with development of the vascular system including sonic hedgehog signaling components patched and smoothened, VEGF-A, angiopoietin-1, endoglin, and Wnt factors compared to wild type hearts. Thus, formation of coronary vasculature is responsive to Tbx18-dependent gene targets in the epicardium, and a poorly structured network of coronary conduit vessels is formed in Tbx18 null hearts due to defects in epicardial cell signaling and fate during heart development. Lastly, we demonstrate that Tbx18 possesses a SRF/CArG box dependent repressor activity capable of inhibiting progenitor cell differentiation into smooth muscle cells, suggesting a potential function of Tbx18 in maintaining the progenitor status of epicardial-derived cells.


Assuntos
Vasos Coronários/embriologia , Vasos Coronários/metabolismo , Pericárdio/embriologia , Pericárdio/metabolismo , Proteínas com Domínio T/metabolismo , Animais , Animais Recém-Nascidos , Diferenciação Celular , Circulação Coronária , Vasos Coronários/patologia , Vasos Coronários/ultraestrutura , Embrião de Mamíferos/metabolismo , Embrião de Mamíferos/patologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Camundongos , Miócitos de Músculo Liso/metabolismo , Pericárdio/patologia , Pericárdio/ultraestrutura , Proteínas Repressoras/metabolismo , Fator de Resposta Sérica/química , Proteínas com Domínio T/deficiência , Proteínas com Domínio T/genética , Transcrição Genética , beta-Galactosidase/metabolismo
17.
Mater Sci Eng C Mater Biol Appl ; 33(4): 2392-8, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23498274

RESUMO

The present study investigates the potential use of non-catalyzed water-soluble blocked polyurethane prepolymer (PUP) as a bifunctional cross-linker for collagenous scaffolds. The effect of concentration (5, 10, 15 and 20%), time (4, 6, 12 and 24 h), medium volume (50, 100, 200 and 300%) and pH (7.4, 8.2, 9 and 10) over stability, microstructure and tensile mechanical behavior of acellular pericardial matrix was studied. The cross-linking index increased up to 81% while the denaturation temperature increased up to 12 °C after PUP crosslinking. PUP-treated scaffold resisted the collagenase degradation (0.167±0.14 mmol/g of liberated amine groups vs. 598±60 mmol/g for non-cross-linked matrix). The collagen fiber network was coated with PUP while viscoelastic properties were altered after cross-linking. The treatment of the pericardial scaffold with PUP allows (i) different densities of cross-linking depending of the process parameters and (ii) tensile properties similar to glutaraldehyde method.


Assuntos
Reagentes para Ligações Cruzadas/farmacologia , Teste de Materiais , Fenômenos Mecânicos/efeitos dos fármacos , Pericárdio/efeitos dos fármacos , Poliuretanos/farmacologia , Água/química , Animais , Cálcio/metabolismo , Varredura Diferencial de Calorimetria , Bovinos , Módulo de Elasticidade/efeitos dos fármacos , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/ultraestrutura , Glutaral/farmacologia , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Pericárdio/ultraestrutura , Fósforo/metabolismo , Estresse Mecânico , Temperatura , Resistência à Tração/efeitos dos fármacos , Fatores de Tempo
18.
Cell Tissue Res ; 351(1): 127-37, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23229355

RESUMO

Insect pericardial cells (PCs) are strategically located along the dorsal vessel where they encounter a high hemolymph flow enabling them to undertake their osmoregulatory, detoxifying, and scavenging functions. In this location, PCs also encounter foreign molecules and microorganisms. The response of PCs of the mosquito Anopheles albimanus, one of the most important Plasmodium vivax vectors in Mexico and Latin America, to Saccharomyces cerevisiae was analyzed by using biochemical, cellular, ultrastructural, and bioinformatics approaches. Immune gene transcripts were identified in the PC transcriptome of A. albimanus. PCs responded to the presence of yeast and zymosan with increased lysosomal and phosphatase activities and produced lytic activity against bacteria. Our results indicate that mosquito PCs play a key role in the neutralization and elimination of pathogens.


Assuntos
Anopheles/citologia , Anti-Infecciosos/metabolismo , Pericárdio/citologia , Fosfatase Ácida/metabolismo , Animais , Feminino , Imunidade/genética , Lisossomos/metabolismo , Pericárdio/imunologia , Pericárdio/microbiologia , Pericárdio/ultraestrutura , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Saccharomyces cerevisiae/fisiologia
19.
Artif Organs ; 37(3): 248-55, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23145868

RESUMO

This study comparatively evaluates the characteristics of glutaraldehyde-treated acellular bovine and donkey pericardium using histological and electronic microscopic observation techniques, shrinkage temperature, and mechanical properties, as well as determining calcium and phosphorus content at 4 and 8 weeks after the subcutaneous implantation of donkey and bovine pericardium in Wistar rats. Donkey pericardium was significantly thinner compared with bovine pericardium (1.622 ± 0.161 mm vs. 4.027 ± 0.401 mm, P < 0.0001) and was associated with significantly greater tensile strength (14.21 ± 3.81 MPa vs. 3.78 ± 1.20 MPa, P = 0.001) and elastic modulus (81.67 ± 20.41 MPa vs. 21.67 ± 11.69 MPa, P < 0.0001) over bovine pericardium. Shrinkage temperature of donkey pericardium was similar to that of bovine pericardium (87.43 ± 0.55°C vs. 87.50 ± 0.36°C, P = 0.810). No differences between groups were observed for maximum load (donkey: 21.64 ± 7.02 KN/m vs. bovine: 15.05 ± 4.50 KN/m, P = 0.082) and tear strength (donkey: 11.54 ± 5.33 MPa vs. bovine: 10.69 ± 3.77 MPa, P = 0.757). Calcium content was significantly lower in donkey pericardium compared with bovine pericardium at 4 weeks (690.15 ± 191.27 µg/g vs. 1381.73 ± 62.52 µg/g, P = 0.001) and 8 weeks (205.24 ± 62.40 µg/g vs. 910.48 ± 398.29 µg/g, P = 0.037). This preliminary study has confirmed that glutaraldehyde-tanned donkey pericardium, demonstrating reduced calcification and increased tensile strength, may provide a suitable bioprosthetic valve substitute.


Assuntos
Bioprótese , Equidae , Implante de Prótese de Valva Cardíaca/instrumentação , Próteses Valvulares Cardíacas , Pericárdio/transplante , Animais , Fenômenos Biomecânicos , Cálcio/metabolismo , Bovinos , Módulo de Elasticidade , Fixadores , Glutaral , Masculino , Pericárdio/metabolismo , Pericárdio/ultraestrutura , Fósforo/metabolismo , Desenho de Prótese , Ratos , Ratos Wistar , Temperatura , Resistência à Tração , Fatores de Tempo , Fixação de Tecidos , Viscosidade
20.
Rev. bras. cir. cardiovasc ; 27(4): 592-599, out.-dez. 2012. ilus, tab
Artigo em Português | LILACS | ID: lil-668121

RESUMO

OBJETIVO: Para melhorar as propriedades mecânicas e imunogênicas, o glutaraldeído é utilizado no tratamento do pericárdio bovino que é utilizado em biopróteses. A liofilização do pericárdio bovino tratado com glutaraldeído diminui os radicais aldeído, com provável redução do potencial para calcificação. O objetivo deste estudo é avaliar os efeitos da liofilização em biopróteses valvares de pericárdio bovino como mecanismo protetor na diminuição da disfunção estrutural valvar. MÉTODOS: Foi realizado o implante de biopróteses de pericárdio bovino tratado com glutaraldeído, liofilizadas ou não, em carneiros de 6 meses de idade, sendo os animais eutanasiados com 3 meses de seguimento. As biopróteses foram implantadas em posição pulmonar, com auxílio de circulação extracorpórea. Um grupo controle e outro grupo liofilizado foram avaliados quanto ao gradiente ventrículo direito/artéria pulmonar (VD/AP) no implante e explante; análise quantitativa de cálcio; inflamação; trombose e pannus. O nível de significância estabelecido foi de 5%. RESULTADOS: O gradiente médio VD/AP, no grupo controle, no implante, foi 2,04 ± 1,56 mmHg e, no grupo de liofilização, foi 6,61 ± 4,03 mmHg. No explante, esse gradiente aumentou para 7,71 ± 3,92 mmHg e 8,24 ± 6,2 mmHg, respectivamente, nos grupos controle e liofilização. O teor de cálcio médio, após 3 meses, nas biopróteses do grupo controle foi 21,6 ± 39,12 µg Ca+2/mg de peso seco, em comparação com um teor médio de 41,19 ± 46,85 µg Ca+2/mg de peso seco no grupo liofilizado (P = 0,662). CONCLUSÃO: A liofilização de próteses valvares com pericárdio bovino tratado com glutaraldeído não demonstrou diminuição da calcificação neste experimento.


OBJECTIVE: Glutaraldehyde is currently used in bovine pericardium bioprosthesis to improve mechanical and immunogenic properties. Lyophilization is a process that may decrease aldehyde residues in the glutaraldehyde treated pericardium decreasing cytotoxicity and enhancing resistance to calcification. The aim of this study is to evaluate bioprosthetic heart valves calcification in adolescent sheep and to study the potential of lyophilization as a mechanism to protect calcification. METHODS: Two groups were evaluated: a control group in which a bovine pericardium prosthetic valve was implanted in pulmonary position and a lyophilized group in which the bovine pericardium prosthetic valve was lyophilized and further implanted. Sixteen sheeps 6 months old were submitted to the operation procedure. After 3 months the sheeps were euthanized under full anesthesia. RESULTS: Six animals of the control group reached 95.16 ± 3.55 days and six animals in the lyophilized group reached 91.66 ± 0.81 days of postoperative evolution. Two animals had endocarditis. Right ventricle/pulmonary artery (RV/PA) mean gradient, in the control group, at the implantation was 2.04 ± 1.56 mmHg, in the lyophilization group, the RV/PA mean gradient, at the implantation was 6.61 ± 4.03 mmHg. At the explantation it increased to 7.71 ± 3.92 mmHg and 8.24 ± 6.25 mmHg, respectively, in control and lyophilization group. The average calcium content, after 3 months, in the control group was 21.6 ± 39.12 µg Ca+2/mg dry weight, compared with an average content of 41.19 ± 46.85 µg Ca+2/mg dry weight in the lyophilization group (P=0.662). CONCLUSION: Freeze drying of the bovine pericardium prosthesis in the pulmonary position could not demonstrate calcification mitigation over a 3 month period although decreased inflammatory infiltration over the tissue.


Assuntos
Animais , Bovinos , Bioprótese/efeitos adversos , Calcinose/prevenção & controle , Próteses Valvulares Cardíacas/efeitos adversos , Teste de Materiais/métodos , Pericárdio/química , Artéria Pulmonar/cirurgia , Calcinose/patologia , Fixadores/farmacologia , Liofilização/métodos , Glutaral/farmacologia , Modelos Animais , Pericárdio/ultraestrutura , Distribuição Aleatória , Ovinos , Estatísticas não Paramétricas
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