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1.
Biomed Mater ; 10(4): 045014, 2015 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-26238213

RESUMO

The capacity of a composite vascular graft constituting polyurethane (PU) and gelatin to support cell growth was investigated using human mesenchymal stem cells (hMSCs). Gelatin-based polyurethane grafts were fabricated by co-spraying polyurethane and gelatin using a spray, phase-inversion technique. Graft microstructure was investigated by light and scanning electron microscopy. Uniaxial tensile tests were performed to assess the grafts' mechanical properties in longitudinal and circumferential directions. hMSCs obtained from bone marrow aspirate were seeded onto flat graft samples. After 24, 48, and 72 h of incubation, cell morphology was evaluated by Giemsa staining and cell viability was calculated by XTT assay. SEM analysis evidenced that PU samples display a microporous structure, whereas the gelatin-based PU samples show a fibrillar appearance. The presence of cross-linked gelatin produced a significant increase of ultimate tensile strength and ultimate elongation in circumferential directions compared to PU material. Qualitative analysis of hMSC adhesion onto the grafts revealed remarkable differences between gelatin-based PU and control graft. hMSCs grown onto gelatin-based PU graft form a monolayer that reached confluence at 72 h, whereas cells seeded onto the control graft were not able to undergo appropriate spreading. hMSCs grown onto gelatin-based PU graft showed significantly higher viability than cells seeded onto bare PU at all time points. In conclusion, a composite vascular graft was successfully manufactured by simultaneous co-spraying of a synthetic polymer and a protein to obtain a scaffold that combines the mechanical characteristics of polyurethanes with the favorable cell interaction features of gelatin.


Assuntos
Materiais Biocompatíveis/síntese química , Prótese Vascular , Gelatina/química , Células-Tronco Mesenquimais/citologia , Poliuretanos/química , Enxerto Vascular/instrumentação , Tamanho Celular , Sobrevivência Celular , Células Cultivadas , Força Compressiva , Módulo de Elasticidade , Desenho de Equipamento , Análise de Falha de Equipamento , Gases/química , Humanos , Teste de Materiais , Células-Tronco Mesenquimais/fisiologia , Transição de Fase , Impressão Tridimensional , Estresse Mecânico , Resistência à Tração
2.
J Biomed Mater Res A ; 103(10): 3284-92, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25809157

RESUMO

As the endothelium still represents the ideal surface for cardiovascular devices, different endothelialization strategies have been attempted for biocompatibility and nonthrombogenicity enhancement. Since endothelial progenitor cells (EPCs) could accelerate endothelialization, preventing thrombosis and restenosis, the aim of this study was to use oligonucleotides (ONs) to biofunctionalize stents for EPC binding. In order to optimize the functionalization procedure before its application to cobalt-chromium (Co/Cr) stents, discs of the same material were preliminarily used. Surface aminosilanization was assessed by infrared spectroscopy and scanning electron microscopy. A fluorescent endothelial-specific ON was immobilized on aminosilanized surfaces and its presence was visualized by confocal microscopy. Fluorescent ON binding to porcine blood EPCs was assessed by flow cytometry. Viability assay was performed on EPCs cultured on unmodified, nontargeting ON or specific ON-coated discs; fluorescent staining of nuclei and F-actin was then performed on EPCs cultured on unmodified or specific ON-coated discs and stents. Disc biofunctionalization significantly increased EPC viability as compared to both unmodified and nontargeting ON-coated surfaces; cell adhesion was also significantly increased. Stents were successfully functionalized with the specific ON, and EPC binding was confirmed by confocal microscopy. In conclusion, stent biofunctionalization for EPC binding was successfully achieved in vitro, suggesting its use to obtain in vivo endothelialization, exploiting the natural regenerative potential of the human body.


Assuntos
Ligas de Cromo/química , Células Endoteliais/metabolismo , Teste de Materiais , Oligonucleotídeos/química , Células-Tronco/metabolismo , Stents , Animais , Adesão Celular , Humanos , Suínos
3.
Acta Biomater ; 9(8): 7814-21, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23603001

RESUMO

Diabetic skin ulcers are difficult to heal spontaneously due to the reduced levels and activity of endogenous growth factors. Recombinant human vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are known to stimulate cell proliferation and accelerate wound healing. Direct delivery of VEGF and bFGF at the wound site in a sustained and controllable way without loss of bioactivity would enhance their biological effects. The aim of this study was to develop a poly(ether)urethane-polydimethylsiloxane/fibrin-based scaffold containing poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with VEGF and bFGF (scaffold/GF-loaded NPs) and to evaluate its wound healing properties in genetically diabetic mice (db/db). The scaffold application on full-thickness dorsal skin wounds significantly accelerated wound closure at day 15 compared to scaffolds without growth factors (control scaffold) or containing unloaded PLGA nanoparticles (scaffold/unloaded NPs). However, the closure rate was similar to that observed in mice treated with scaffolds containing free VEGF and bFGF (scaffold/GFs). Both scaffolds containing growth factors induced complete re-epithelialization, with enhanced granulation tissue formation/maturity and collagen deposition compared to the other groups, as revealed by histological analysis. The ability of the scaffold/GF-loaded NPs to promote wound healing in a diabetic mouse model suggests its potential use as a dressing in patients with diabetic foot ulcers.


Assuntos
Bandagens , Pé Diabético/tratamento farmacológico , Fibrina/química , Fator 2 de Crescimento de Fibroblastos/administração & dosagem , Alicerces Teciduais , Fator A de Crescimento do Endotélio Vascular/administração & dosagem , Cicatrização/efeitos dos fármacos , Animais , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/química , Pé Diabético/patologia , Combinação de Medicamentos , Fator 2 de Crescimento de Fibroblastos/química , Masculino , Teste de Materiais , Camundongos , Camundongos Transgênicos , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/química , Cicatrização/fisiologia
4.
Recenti Prog Med ; 104(1): 1-9, 2013 Jan.
Artigo em Italiano | MEDLINE | ID: mdl-23439534

RESUMO

Peripheral artery disease and related revascularization procedures are increasing, due to the aging population and growing incidence of diabetes mellitus. Up to now, autologous saphenous vein is the conduit of choice for peripheral by-pass. Synthetic vascular graft in polyethylene terephthalate (Dacron®) and expanded polytetrafluoroethylene (ePTFE) are used if vein access cannot be obtained. These synthetic grafts are successfully used to replace large diameter vessels, but they fail in small diameters (<6 mm) such as for infragenicular by-pass. Reasons for failure are early thrombosis and late intimal hyperplasia. Novel small-diameter vascular grafts with an acceptable clinical outcome are therefore needed. Here, the main materials and technologies for the manufacturing of vascular grafts and the pathway from bench to bedside are discussed .


Assuntos
Materiais Biocompatíveis , Implante de Prótese Vascular/métodos , Prótese Vascular , Polietilenotereftalatos , Politetrafluoretileno , Animais , Ensaios Clínicos como Assunto , Humanos , Hiperplasia , Implantes Experimentais , Teste de Materiais , Modelos Animais , Doença Arterial Periférica/cirurgia , Adesividade Plaquetária , Complicações Pós-Operatórias/etiologia , Falha de Prótese , Trombose/etiologia , Pesquisa Translacional Biomédica , Túnica Íntima/patologia
5.
PLoS One ; 8(12): e84753, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24386412

RESUMO

BACKGROUND: Platelets are rich in mediators able to positively affect cell activity in wound healing. Aim of this study was to characterize the effect of different concentrations of human pooled allogeneic platelet lysate on human cells involved in the different phases of wound healing (inflammatory phase, angiogenesis, extracellular matrix secretion and epithelialization). METHODOLOGY/PRINCIPAL FINDINGS: Platelet lysate effect was studied on endothelial cells, monocytes, fibroblasts and keratinocytes, in terms of viability and proliferation, migration, angiogenesis, tissue repair pathway activation (ERK1/2) and inflammatory response evaluation (NFκB). Results were compared both with basal medium and with a positive control containing serum and growth factors. Platelet lysate induced viability and proliferation at the highest concentrations tested (10% and 20% v/v). Whereas both platelet lysate concentrations increased cell migration, only 20% platelet lysate was able to significantly promote angiogenic activity (p<0.05 vs. control), comparably to the positive control. Both platelet lysate concentrations activated important inflammatory pathways such as ERK1/2 and NFκB with the same early kinetics, whereas the effect was different for later time-points. CONCLUSION/SIGNIFICANCE: These data suggest the possibility of using allogeneic platelet lysate as both an alternative to growth factors commonly used for cell culture and as a tool for clinical regenerative application for wound healing.


Assuntos
Plaquetas/química , Proliferação de Células , Células Endoteliais da Veia Umbilical Humana/metabolismo , Sistema de Sinalização das MAP Quinases , Cicatrização , Linhagem Celular , Sobrevivência Celular , Células Endoteliais da Veia Umbilical Humana/citologia , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , NF-kappa B/metabolismo
6.
J Mater Sci Mater Med ; 23(9): 2235-43, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22692367

RESUMO

Negative-pressure wound therapy (NPWT) also known as V.A.C. (Vacuum-assisted closure), is widely used to manage various type of wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane (PU) foam or medical gauze. In this study an experimental setup of sheep wound model was used to evaluate, under NPWT conditions, the performance of a silicone-coated non-woven polyester (N-WPE) compared with PU foam and cotton hydrophilic gauze, used as reference materials. Animals were anesthetized with spontaneous breathing to create three 3 × 3 cm skin defects bilaterally; each animal received three different samples on each side (n = 6 in each experimental group) and was subjected to negative and continuous 125 mmHg pressure up to 16 days. Wound conditions after 1, 8 and 16 days of treatment with the wound dressings were evaluated based on gross and histological appearances. Skin defects treated with the silicone-coated N-WPE showed a significant decrease in wound size, an increase of re-epithelialization, collagen deposition and wound neovascularisation, and a minimal stickiness to the wound tissue, in comparison with gauze and PU foam. Taken all together these findings indicate that the silicone-coated N-WPE dressing enhances wound healing since stimulates higher granulation tissue formation and causes minor tissue trauma during dressing changes.


Assuntos
Bandagens , Derme/lesões , Poliésteres/química , Reepitelização/fisiologia , Silicones/química , Anatomia Transversal , Animais , Materiais Revestidos Biocompatíveis/síntese química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Derme/anatomia & histologia , Derme/patologia , Derme/ultraestrutura , Modelos Animais de Doenças , Tratamento de Ferimentos com Pressão Negativa/instrumentação , Tratamento de Ferimentos com Pressão Negativa/métodos , Curativos Oclusivos , Permeabilidade/efeitos dos fármacos , Poliésteres/síntese química , Poliésteres/farmacologia , Reepitelização/efeitos dos fármacos , Ovinos , Silicones/farmacologia , Cicatrização/efeitos dos fármacos , Cicatrização/fisiologia
7.
PLoS One ; 7(4): e34284, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22509287

RESUMO

AIMS: A potential therapy for myocardial infarction is to deliver isolated stem cells to the infarcted site. A key issue with this therapy is to have at one's disposal a suitable cell delivery system which, besides being able to support cell proliferation and differentiation, may also provide handling and elastic properties which do not affect cardiac contractile function. In this study an elastic scaffold, obtained combining a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (s-IPN) with fibrin, was used as a substrate for in vitro studies of human amniotic mesenchymal stromal cells (hAMSC) growth and differentiation. METHODOLOGY/PRINCIPAL FINDINGS: After hAMSC seeding on the fibrin side of the scaffold, cell metabolic activity and proliferation were evaluated by WST-1 and bromodeoxyuridine assays. Morphological changes and mRNAs expression for cardiac differentiation markers in the hAMSCs were examined using immunofluorescence and RT-PCR analysis. The beginning of cardiomyogenic commitment of hAMSCs grown on the scaffold was induced, for the first time in this cell population, by a nitric oxide (NO) treatment. Following NO treatment hAMSCs show morphological changes, an increase of the messenger cardiac differentiation markers [troponin I (TnI) and NK2 transcription factor related locus 5 (Nkx2.5)] and a modulation of the endothelial markers [vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR)]. CONCLUSIONS/SIGNIFICANCE: The results of this study suggest that the s-IPN PEtU-PDMS/fibrin combined scaffold allows a better proliferation and metabolic activity of hAMSCs cultured up to 14 days, compared to the ones grown on plastic dishes. In addition, the combined scaffold sustains the beginning of hAMSCs differentiation process towards a cardiomyogenic lineage.


Assuntos
Dimetilpolisiloxanos/química , Fibrina/farmacologia , Células-Tronco Mesenquimais/citologia , Miocárdio/citologia , Placenta/citologia , Poliuretanos/química , Alicerces Teciduais , Actinas/genética , Âmnio/citologia , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Fibrina/química , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Óxido Nítrico/farmacologia , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Engenharia Tecidual , Vimentina/genética
8.
J Surg Res ; 163(2): e53-8, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20691995

RESUMO

BACKGROUND: In recent years, the use of synthetic glues has become an established practice in several areas of surgical treatment. For example, they are used in open and laparoscopic surgery and in digestive tract endoscopy, interventional radiology, and vascular neuroradiology. The experiments in this study were aimed at elucidating that suture-based permanent mesh fixation can be replaced by fixation with N-butyl 2-cyanoacrylate glue (Glubran2) for surgical repair of abdominal wall hernias. MATERIALS AND METHODS: In 25 Wistar rats, two hernia defects (1.5 cm in diameter) per animal were created bilaterally in the midline of the abdominal wall. The peritoneum was spared. The lesions were left untreated for 10 d to achieve a chronic condition. Then the defects were covered with TiMESH extralight (2 × 2 cm) and fixed by 30 µL of Glubran2 or traditional suture. The time points of sacrifice were 17 and 28 d, 3, 4, and 5 mo. At autopsy, histology and immunohistochemistry were performed to evaluate the inflammatory response and the presence of apoptotic cells respectively. RESULTS: Mesh fixation was excellent in all samples at each time point. At application sites, the inflammatory reaction was mild with a small number of macrophages and vascularized connective tissue presence around glue and mesh threads. Glue residues were observed in histologic sections at each time point. No presence of apoptotic cells was found. CONCLUSIONS: This study demonstrated that Glubran2 can effectively replace traditional suture in mesh fixation without affecting tissue healing and determining a physiological inflammatory reaction at the abdominal wall site.


Assuntos
Cianoacrilatos , Hérnia Abdominal/cirurgia , Telas Cirúrgicas , Suturas , Adesivos Teciduais , Animais , Hérnia Abdominal/patologia , Imuno-Histoquímica , Masculino , Ratos , Ratos Wistar , Cicatrização
9.
Biomaterials ; 31(20): 5336-44, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20381861

RESUMO

The development of a scaffold able to mimic the mechanical properties of elastic tissues and to induce local angiogenesis by controlled release of angiogenic growth factors could be applied in the treatment of several ischemic diseases. For this purpose a composite scaffold made of a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (semi-IPN) and fibrin loaded growth factors (GFs), such as VEGF and bFGF, was manufactured using spray, phase-inversion technique. To evaluate the contribution of each scaffold component with respect to tissue response and in particular to blood vessel formation, three different scaffold formulations were developed as follows: 1) bare PEtU-PDMS; 2) PEtU-PDMS/Fibrin; and 3) PEtU-PDMS/Fibrin + GFs. Scaffolds were characterized in vitro respect to their morphology, VEGF and bFGF release kinetics and bioactivity. The induction of in vivo angiogenesis after subcutaneous and ischemic hind limb scaffold implantation in adult Wistar rats was evaluated at 7 and 14 days by immunohistological analysis (IHA), while Laser Doppler Perfusion Imaging (LDPI) was performed in the hind limbs at 0, 3, 7, 10 and 14 days. IHA of subcutaneously implanted samples showed that at 7 and 14 days the PEtU-PDMS/Fibrin + GFs scaffold induced a statistically significant increase in number of capillaries compared to bare PEtU-PDMS scaffold. IHA of ischemic hind limb showed that at 14 days the capillary number induced by PEtU-PDMS/Fibrin + GFs scaffolds was higher than that of PEtU-PDMS/Fibrin scaffolds. Moreover, at both time-points PEtU-PDMS/Fibrin scaffolds induced a significant increase in number of capillaries compared to bare PEtU-PDMS scaffolds. LDPI showed that at 10 and 14 days the ischemic/non-ischemic blood perfusion ratio was significantly greater in the PEtU-PDMS/Fibrin + GFs than in the other scaffolds. In conclusion, this study showed that the semi-IPN composite scaffold acting as a pro-angiogenic GFs delivery system has therapeutic potential for the local treatment of ischemic tissue and wound healing.


Assuntos
Indutores da Angiogênese/farmacologia , Dimetilpolisiloxanos/farmacologia , Fibrina/farmacologia , Fator 2 de Crescimento de Fibroblastos/farmacologia , Poliuretanos/farmacologia , Alicerces Teciduais/química , Fator A de Crescimento do Endotélio Vascular/farmacologia , Animais , Preparações de Ação Retardada , Modelos Animais de Doenças , Membro Posterior/irrigação sanguínea , Membro Posterior/efeitos dos fármacos , Humanos , Imuno-Histoquímica , Isquemia/patologia , Cinética , Microscopia Eletrônica de Varredura , Neovascularização Fisiológica/efeitos dos fármacos , Ratos , Ratos Wistar
10.
J Mater Sci Mater Med ; 21(4): 1311-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20091101

RESUMO

Poly(ether) urethane (PEtU)-polydimethylsiloxane (PDMS) based materials have been processed by a spray, phase-inversion technique to produce microfibrillar small-diameter vascular grafts; however the effect of sterilization upon these grafts is still unknown. This study investigated the effect of gamma irradiation on grafts made of PEtU-PDMS materials containing different PDMS concentrations. Sterilisation-induced changes in surface chemical structure and morphology were assessed by infrared spectroscopy, light and scanning electron microscopy. Tensile tests were used to examine changes in mechanical properties and the cytotoxicity evaluation was performed on L929 fibroblasts. The study demonstrated that physical-chemical and mechanical properties of PEtU-PDMS grafts, at each PDMS concentration, were not significantly affected by the exposure to gamma irradiation, moreover no sign of cytotoxicity was observed after sterilisation. Although in vitro experiments have been promising, further in vivo studies are necessary to evaluate the biodegradation behaviour of PEtU-PDMS graft after gamma irradiation, before any clinical application.


Assuntos
Fenômenos Biomecânicos/efeitos da radiação , Prótese Vascular/efeitos adversos , Dimetilpolisiloxanos/efeitos adversos , Dimetilpolisiloxanos/efeitos da radiação , Raios gama , Fenômenos Físicos , Poliuretanos/efeitos adversos , Poliuretanos/efeitos da radiação , Implantes Absorvíveis/efeitos adversos , Animais , Materiais Biocompatíveis/efeitos adversos , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/efeitos da radiação , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Dimetilpolisiloxanos/química , Dimetilpolisiloxanos/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Raios gama/efeitos adversos , Teste de Materiais , Camundongos , Microfibrilas/química , Microfibrilas/efeitos da radiação , Poliuretanos/química , Poliuretanos/farmacologia , Esterilização/métodos , Estresse Mecânico , Propriedades de Superfície/efeitos da radiação , Resistência à Tração/efeitos da radiação
11.
Biomaterials ; 31(9): 2592-605, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20035992

RESUMO

In the past years considerable research efforts have been directed at developing more suitable synthetic vascular grafts, but small-diameter vascular grafts (SDVGs) perform less well than autogenous arterial or venous grafts. Grafts such as Dacron and ePTFE have often been used as alternatives to autologous grafts, but they have shown poor patency rates when used in small-diameter sizes or low-flow locations. Nevertheless, despite these efforts no alternative concepts have emerged yet that promises to replace the current generation of synthetic grafts soon. The purpose of this preliminary in vivo study was to assess the blood and tissue compatibility behaviors of a novel compliant SDVGs, fabricated with a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (semi-IPN) and featuring two different porous layers in the wall thickness. Grafts were implanted according to anastomotic techniques which emulate the flow conditions clinically adopted for peripheral or aorto-coronary bypass procedures. Relatively long grafts were implanted in the common carotid artery of adult sheep and compared to standard ePTFE grafts of the same size and length implanted controlaterally. The animal experimentation showed superior handling and compliance characteristics, and patency rates of PEtU-PDMS grafts in comparison with a standard ePTFE graft, and the ability of remodelling in vivo while being gradually replaced by a natural tissue with no sign of calcification.


Assuntos
Prótese Vascular , Dimetilpolisiloxanos/farmacologia , Poliuretanos/farmacologia , Animais , Artéria Carótida Primitiva/diagnóstico por imagem , Artéria Carótida Primitiva/efeitos dos fármacos , Artéria Carótida Primitiva/patologia , Complacência (Medida de Distensibilidade)/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Neovascularização Fisiológica/efeitos dos fármacos , Especificidade de Órgãos/efeitos dos fármacos , Implantação de Prótese , Radiografia , Ovinos , Fatores de Tempo
12.
J Control Release ; 142(1): 14-21, 2010 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-19811766

RESUMO

The aim of this study was to fabricate and characterize in vitro a novel composite scaffold that, combining good mechanical properties with a controlled and sustained release of bioactive pro-angiogenetic growth factors, should be useful for angiogenesis induction in organs/tissues in which is also necessary to give resistance and mechanical strength. Composite scaffolds, constituted by a synthetic biocompatible material, a poly(ether)urethane-polydimethylsiloxane blend, and a biological polymer, the fibrin, were manufactured by spray, phase-inversion technique. During the manufacturing process heparin and heparin-binding growth factors, such as VEGF(165) and bFGF, were incorporated into the fibrin layer. Microscopical examinations showed a homogeneous fibrin layer firmly adherent on top of the synthetic material. Tensile tests highlighted the high elasticity of the composite scaffold and its capability to maintain integrity up to high deformation. VEGF(165) and bFGF release were controlled by fibrinogen concentration, whereas it was not affected by heparin concentration, as revealed by ELISA assay. The biological activity of the released growth factors was maintained as demonstrated by HUVEC proliferation. Finally, scaffolds induced a low monocyte mRNA expression of inflammatory markers (IL-8, L-SEL, LFA-1 and iNOS). In conclusion, the new composite scaffolds, once implanted, providing a co-localization and temporal distribution of bioactive VEGF and bFGF in addition to good mechanical properties, may be useful to stimulate new vessels formation in ischemic tissues.


Assuntos
Indutores da Angiogênese/administração & dosagem , Preparações de Ação Retardada/química , Fibrina/química , Fator 2 de Crescimento de Fibroblastos/administração & dosagem , Alicerces Teciduais/química , Fator A de Crescimento do Endotélio Vascular/administração & dosagem , Indutores da Angiogênese/farmacologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Dimetilpolisiloxanos/química , Módulo de Elasticidade , Células Endoteliais/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/farmacologia , Expressão Gênica/efeitos dos fármacos , Humanos , Teste de Materiais , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Monócitos/metabolismo , Poliuretanos/química , Propriedades de Superfície , Fator A de Crescimento do Endotélio Vascular/farmacologia
13.
J Surg Res ; 157(1): e15-21, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19439320

RESUMO

BACKGROUND: In surgical and endoscopic procedures, tissue adhesives are commonly used as reinforcement of sutures or as bonding and hemostatic agents. Fibrin glues do not guarantee adequate properties for many clinical applications; on the contrary, cyanoacrylate glues guarantee high bonding strength between biologic tissues. The aim of this study was to provide evidence regarding adhesive and strength properties of a widely used cyanoacrylate glue, Glubran2, GEM s.r.l., Viareggio, Italy. Comparative tests were also carried out on a commercial fibrin glue. MATERIAL AND METHODS: Glubran2 is a modified n-butyl-2-cyanoacrylate glue approved for internal and external use, in Europe. The glue, on contact with living tissues polymerizes rapidly, generating a film that guarantees firm adherence of tissues. In this study, adhesive properties on biologic substrates, both of Glubran2 and of fibrin glue, were investigated according to American Society for Testing and Materials (ASTM) standards, while their strength, after polymerization on an inert substrate, was investigated according to Deutsches Institut Für Normung (DIN) standards. RESULTS: All tests evidenced a strong bonding capability of Glubran2 on biologic tissues and high tensile strength of polymerized film; high breaking strength of polymerized glue was highlighted by tensile tests. CONCLUSION: The present study fills the gap concerning Glubran2 adhesive and tensile properties. All tests showed the intrinsic tensile strength of polymerized Glubran2 and its capability to realize a higher-resistance bonding among biologic tissues, in comparison with fibrin glue, giving strong indication of its usefulness in surgical and endoscopic practice, especially in a wet environment.


Assuntos
Adesivos/farmacologia , Cianoacrilatos/farmacologia , Pele , Estresse Mecânico , Resistência à Tração , Animais , Elasticidade , Adesivo Tecidual de Fibrina/farmacologia , Técnicas In Vitro , Teste de Materiais , Polímeros , Suínos
14.
J Mater Sci Mater Med ; 18(10): 1939-44, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17554600

RESUMO

The degree of integration of biomaterials used in the repair of abdominal wall defects seems to depend upon the structure of the prosthesis. The present investigation evaluates the behaviour in terms of adhesion formation and integration of a new composite prosthesis that could be employed in this clinical application. Full-thickness abdominal wall defects (7 x 5 cm) were created in 16 anaesthetized New Zealand white rabbits and the prosthesis were placed in direct contact with the visceral peritoneum during the experiment. The defects were repaired with a composite prosthesis or pure polypropylene mesh to establish two study groups (n = 8 each). The composite device was constituted by a polypropylene mesh physically attached to a poly(ether)urethane-polydimethylsiloxane laminar sheet. Animals were sacrificed 7, 14, 21 and 30 days after implant and prosthesis/surrounding tissue specimens subjected to light and electron microscopy. Firm adhesions were detected in the polypropylene implants, while they were not present in the composite implants. The excellent behaviour of the composite prosthesis shown in this study warrants further investigation on its use for the repair of abdominal wall defects when a prosthetic device needs to be placed in contact with the intestinal loops.


Assuntos
Parede Abdominal/fisiologia , Hérnia Abdominal/cirurgia , Polímeros/uso terapêutico , Próteses e Implantes , Implantação de Prótese , Regeneração , Animais , Dimetilpolisiloxanos/química , Interações Hidrofóbicas e Hidrofílicas , Masculino , Microscopia Eletrônica de Varredura , Polímeros/síntese química , Poliuretanos/química , Coelhos , Silicones/química , Telas Cirúrgicas , Aderências Teciduais/diagnóstico , Molhabilidade
15.
J Mater Sci Mater Med ; 18(6): 1097-104, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17268875

RESUMO

An unsolved problem when employing small-diameter vascular grafts for aorto-coronary by-pass and peripheral reconstruction is the early thrombotic occlusion. The PEtU-PDMS is a new elastomeric material, composed of poly(ether)urethane and polydimethylsiloxane, synthesized to realize grafts with improved hemocompatibility characteristics. In order to investigate the effect of PDMS content on hemocompatibility, three different percentages of PDMS containing grafts (10, 25 and 40) were evaluated. Grafts realized with Estane 5714-F1 and silicone medical grade tubes were used as references. The hemocompatibility was investigated by an in vitro circuit in which human anticoagulated blood was circulated into grafts by a peristaltic pump modified to obtain a passive flow. For each experiment, 40 cm length graft was closed into a circular loop and put in rotation for 2 h at 37 degrees C. At the end of the experiments different parameters regarding platelet adhesion and activation were evaluated: circulating platelets count, beta-thromboglobulin release, platelet CD62P expression and amount of monocyte-platelet conjugates. PEtU-PDMS grafts with 25 and 40% of PDMS induced the lowest platelet adhesion, plasma level of beta-TG and amount of monocyte-platelet conjugates. No significative variations were observed in CD62P expression. In conclusion, PDMS content significatively affects blood-graft surface interaction, in fact higher PDMS percentage containing grafts showed the best in vitro hemocompatibility.


Assuntos
Materiais Biocompatíveis/química , Prótese Vascular , Dimetilpolisiloxanos/química , Dimetilpolisiloxanos/farmacologia , Hemólise , Nylons/química , Nylons/farmacologia , Adulto , Plaquetas/efeitos dos fármacos , Humanos , Teste de Materiais/métodos , Monócitos/fisiologia , Selectina-P/metabolismo , Adesividade Plaquetária/efeitos dos fármacos , beta-Tromboglobulina/metabolismo
16.
Biomaterials ; 25(18): 4447-55, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15046935

RESUMO

One of the major problems when using small-diameter vascular grafts in arterial reconstruction is the development of platelet-rich thrombi as a consequence of blood contact with artificial surfaces. The degree of occlusion is certainly affected by the thrombogenicity of the internal surface that seems to play a key role in patency and long-term wound healing of grafts. In this study, the blood compatibility of Cardiothane (CA) vascular grafts was investigated. The CA material, a blend of polyurethane and polydimethylsiloxane that has shown relatively good physical and biocompatibility properties, was manufactured into vascular grafts by the instrument named "spray-machine". Grafts with different luminal surface porosity were produced using increasing CA concentrations by the "spray-machine" and the blood compatibility was evaluated in vitro by a circulation system in which the human blood was allowed to interact with the material in a well-controlled setting. The samples of circulating blood were collected at different times of circulation and platelet adhesion and activation were studied. Grafts with a highly porous luminal surface induced a lower adhesion and activation of platelets in vitro than the low-porosity ones. These results underlined the importance of the microgeometry of the graft luminal surface in the interaction with blood.


Assuntos
Materiais Biocompatíveis/química , Plaquetas/fisiologia , Prótese Vascular , Teste de Materiais/métodos , Adesividade Plaquetária/fisiologia , Poliuretanos/química , Elastômeros de Silicone/química , Transplantes , Fenômenos Fisiológicos Sanguíneos , Plaquetas/citologia , Células Cultivadas , Hemólise/fisiologia , Humanos , Teste de Materiais/instrumentação , Ativação Plaquetária/fisiologia , Propriedades de Superfície
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