Veronique Viateau - Academia.edu (original) (raw)

Papers by Veronique Viateau

Research paper thumbnail of La Vascularisation Osseuse Du Segment Intermediaire Dans Les Transferts Osseux Selon Ilizarov (Etude Experimentale Chez La Brebis)

MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Research paper thumbnail of Tissue-engineered bone regeneration

Nature Biotechnology, 2000

Research paper thumbnail of Biomechanical evaluation of a bioactive artificial anterior cruciate ligament

Advances in biomechanics and applications, 2014

This study aimed to assess the biomechanical performance of a new generation of artificial ligame... more This study aimed to assess the biomechanical performance of a new generation of artificial ligament, which can be considered "bioactive" and "biointegrated," implanted in sheep. Thirty sheep were implanted: 15 sheep received the artificial ligament grafted with a bioactive polymer (grafted) and 15 received the artificial ligament without a bioactive polymer (non-grafted). The animals were sacrificed 3 or 12 months after implantation. The knee kinematics, namely flexion-extension, anterior drawer, and varusvalgus tests, were evaluated using a fully characterized custom-made device. Afterward, the specimens were tested under uniaxial tension until failure. The flexion-extension showed significant differences between (grafted or non-grafted) artificial and native ligaments 3 months after implantation. This difference became non-significant 12 months postoperatively. The anterior tibial drawer was significantly increased 3 months after implantation and remained significantly different only for non-grafted ligament 12 months after implantation. Twelve months after implantation, the differences between grafted and non-grafted ligament biomechanical properties were significant in terms of stiffness. In terms of load to failure, grafted ligaments seem to have had slightly better performance than non-grafted ligaments 12 months postoperatively. Overall these results suggest that grafted artificial ligaments have slightly better biomechanical characteristics than non-grafted artificial ligaments 12 months after implantation in sheep.

Research paper thumbnail of Bone tissue response induced by bioactive polymer functionalized Ti6Al4V surfaces: In vitro and in vivo study

Journal of colloid and interface science, Jan 18, 2016

Ti6Al4V is commonly used for orthopedic applications. This study was designed to test the potenti... more Ti6Al4V is commonly used for orthopedic applications. This study was designed to test the potentially added benefit of Ti6Al4V functionalized with a bioactive polymer poly(sodium styrene sulfonate) both in vitro and in vivo. Cell-based assays with MC3T3-E1 osteoblast-like cells were used to measure the cell adhesion strength, cell spreading, focal contact formation, cell differentiation and the mineralization of extracellular matrix on grafted and ungrafted Ti6Al4V discs in combination with FBS and collagen type I. Bone morphogenetic protein-2 (BMP-2) was also included in the cell differentiation assay. Results showed that the grafted surface combined with collagen I gave superior levels in every parameter tested with cell-based assays and was almost equivalent to BMP-2 for cell differentiation. In vivo testing was conducted in rabbits (n=42) with cylinders of grafted and ungrafted Ti6Al4V implanted in defects made to the femoral and lateral condyles and animals that were maintained...

Research paper thumbnail of Reconstruction De Perte De Substance Osseuse Massive Par La Procédure De Masquelet : Modèle Expérimental Chez La Brebis

Journal of Bone Joint Surgery British Volume, Jul 1, 2008

Purpose of the study: The objective of this study was to establish an experimental sheep model fo... more Purpose of the study: The objective of this study was to establish an experimental sheep model for a surgical procedure which has been clinically successful for repairing major loss of bone stock: the Masquelet technique. Material and methods: A 25 mm bone defect was created in a metatarsal bone then filled with a cement filler. After six weeks, the cement was removed after opening the neoformed pseudosynovial membrane. The cavity was left empty in group 1 (n=6) or filled with a morcelized cancellous autograft harvested from the iliac crests in group 1 (n=6). Results: The surgery was well tolerated in all animals which were able to used the injured limb the day after the operation. Radiographic images and histological findings 24 weeks after surgery demonstrated that healing had not been achieved in all of the animals in group 1. Inversely, healing was achieved in all animals in group 2 at 24 weeks. Immunohistochemistry of the neoformed pseudosynovial demonstrated : an abundant vascular network, presence of cells expressing transcription factor CBFA1, very few inflammatory CD14+ cells (macrophages), an extracellular matrix positive for type I collagen. Conclusion: The sheep metatarsal model is a model of critical size with low morbidity. This model could be used to: evaluate new therapeutic strategies for bone regeneration in conditions close to clinical situations, study the role of the membrane in bone repair. The presence of a pseudosynovial membrane might: be a barrier against the diffusion of bone morphogenetic proteins outside the lesion and potentially be a reservoir of stem and vascular cells which could be useful for new technologies.

Research paper thumbnail of �valuation Clinique et Biologique D�un Ligament Synth�tique Bioactif Chez La Brebis

Research paper thumbnail of Comparison of Survival and Osteogenic Ability of Human Mesenchymal Stem Cells in Orthotopic and Ectopic Sites in Mice

Tissue Engineering Part A, 2016

Research paper thumbnail of 250. Effects of RH-BMP-2 (Inductos) on the Bone Healing Phase of a Distraction Osteogenesis Model

Journal of Bone Joint Surgery British Volume, Nov 1, 2011

Purpose of the study: The process of bone lengthening involves three phases: a latence period, di... more Purpose of the study: The process of bone lengthening involves three phases: a latence period, distraction, then healing. The healing phase required stability maintained by an external fixator (EF) for 1.16 months/cm lengthening. This time exposes the patient to serious complications. The objective is to accelerate the healing phase in order to shorten the time the patient has to wear the EF. The effect of BMP on osteogenesis in distraction remains a controversial issue. This work was conducted to evaluate the benefit provided by rhBMP-2 for healing the regenerate bone after distraction. Material and methods: Thirty-nine subadult male rabbits were selected at random. On day 0, a tibial osteotomy was performed followed by installation of a M101 EF. After the latency period of seven days, the distraction began at the rate of 0.5mm/12 h for 21 days. At day 28, at the end of distraction, a new operation was performed and three groups of 13 individuals were created at random. The first group received no material, the second a collagen type 1 sponge, and the third group a collagen type 1 sponge soaked in 100 μg/kg rhBMP-2. The animals were monitored with x-rays, absorptiometry and ultrasound for the qualitative and quantitative analysis. Histological and biomechanical analyses were performed at two months. Results: Our complication rate was 41%. Qualitative analysis of the x-rays showed, in group 3, the development of more or less voluminous and dense, sometimes hypertrophic calluses. The progression curves of the bone mineral content showed higher values in group 3. The bone mineral content curves remained nevertheless parallel for the three groups. The calluses were thus denser in group 3 but with an early peak density. Groups 1 and 2 had equivalent radiographic and absorptiometric results. The statistical analysis of the imaging findings is ongoing. The histology and biomechanical exams are being performed. Discussion: The preliminary results show that rhBMP-2 used early in the healing phase enables formation of more dense and hypertrophic calluses. rhBMP-2 does not acceleration the rate of callus formation but stimulates its mineralization. Use of a collagen sponge alone had no effect on healing. Analysis of the histological and mechanic properties observed in the three groups will provide a more precise description of the hypertrophic and strongly mineralized calluses. Conclusion: Our early results show superior bone mineralization in the treated group.

Research paper thumbnail of Traitement chirurgical d'une fracture vertébrale lombaire

Le Point Veterinaire Revue D Enseignement Post Universitaie Et De Formation Permanente, 2010

Chez le chien, les fractures vertebrales lombaires sont presque toujours secondaires a un acciden... more Chez le chien, les fractures vertebrales lombaires sont presque toujours secondaires a un accident de la voie publique et souvent associees a d'autres atteintes lesionnelles. Le scanner revet un interet particulier dans le bilan lesionnel de ces fractures et le choix du traitement. La presence d'une instabilite vertebrale necessite une reduction et une stabilisation chirurgicales. Le choix de la technique repose alors sur des criteres anatomiques et biomecaniques.

Research paper thumbnail of A New, Segmental, Critical-Size Defect Model for Long Bones: A Sheep Study

Key Engineering Materials, 2006

Introduction Reconstruction of large segmental bone defects can be achieved by a two-steps proced... more Introduction Reconstruction of large segmental bone defects can be achieved by a two-steps procedure using cancellous bone chips as described by Masquelet et al. In a first surgical procedure a PMMA-cement spacer is inserted into the defect. The presence of this foreign body triggers the formation of a pseudo-synovial membrane. After 8 weeks, the cement spacer is removed leaving a cavity surrounded by a membrane. This cavity is then filled with autologous cancellous (ACG) graft. Successful repairs of bone losses up to 25 cm long have been reported in human with this technique. It, however, requires large quantities of autograft and, sometimes successive surgeries need to be performed to achieve bone union. The discovery of growth factors and skeletal stem cells have opened new avenues for designing highly efficient bone substitutes. A key step in the development of these novel biomaterials is their in vivo assessment in clinically relevant animal models. In the present study, we set up a animal model that mimicked the surgical procedure described by Masquelet and explore the possibility of using skeletal stem cells loaded onto a coral scaffolds to repair such defects. Materials and Methods MSCs amplification: MSCs are expanded in 10% FCS with osteogenic supplements. Surgical model: 20 adult sheep underwent a 2.5 cm long mid diaphyseal bone resection of the metatarsus that was filled with a cement spacer for 6 weeks. At that time cement was carefully removed through an incision made along the formed pseudo-synovial membrane and replaced according the following protocols: Experimental groups Control groups: Defects left empty (n=4) or filled either with coral cubes (n=5) or autologous cancellous bone chips (n=5) harvested at the iliac crest were implanted as controls.Coral+MSCs group: constructs are composed of MSCs loaded onto natural coral cubes 3mm (n=7). Cells are loaded onto the scaffold 15 days prior to implantation and cultured under dynamic conditions. Animals were anaesthetized and radiographed every 4 weeks until they were sacrified, by intravenous barbiturate overdose, 24 weeks after surgery. Results Establishment of the animal model recherche médicale as well as the CNRS and l'INSERM. Reference: Masquelet AC, Fitoussi F, Begue T, et al. [Reconstruction of the long bones by the induced membrane and spongy autograft]. Ann

Research paper thumbnail of Corpectomie vidéo-assistée (CVA) : étude cadavérique et résultats cliniques préliminaires

Pratique Médicale et Chirurgicale de l'Animal de Compagnie, 2011

Research paper thumbnail of Animal Models for Bone Tissue Engineering Purposes

Sourcebook of Models for Biomedical Research

Page 1. 725 74 Animal Models for Bone Tissue Engineering Purposes VÉRONIQUE VIATEAU, DELPHINE LOG... more Page 1. 725 74 Animal Models for Bone Tissue Engineering Purposes VÉRONIQUE VIATEAU, DELPHINE LOGEART-AVRAMOGLOU, GENEVIÈVE GUILLEMIN, AND HERVÉ PETITE ABSTRACT To assess the efficacy of engineered ...

Research paper thumbnail of Animal Models for Orthopedic Applications of Tissue Engineering

Migonney/Biomaterials, 2014

Research paper thumbnail of Induction of a Barrier Membrane to Facilitate Reconstruction of Massive Segmental Diaphyseal Bone Defects: An Ovine Model

Veterinary Surgery, 2006

Objectives-To report an ovine model that can be used to evaluate the efficacy of bone substitutes... more Objectives-To report an ovine model that can be used to evaluate the efficacy of bone substitutes for repair of segmental diaphyseal bone defects. Study Design-Experimental study. Animals-Eleven 2-year-old Pre´-Alpes Sheep. Methods-Mid-diaphyseal metatarsal bone defects (25 mm long) were stabilized by a dynamic compression plate over a polymethylmethacrylate (PMMA) cement spacer, and by external coaptation. The PMMA spacer was removed at 6 weeks by incising the encapsulating membrane. The defect remained unfilled (Group 1; n ¼ 5) or was filled with morselized autologous corticocancellous graft (Group 2; n ¼ 6), the membrane sutured closed, and external coaptation applied for 6 months, when healing was evaluated. Results-Radiographic, computed tomographic, and histologic examinations at 6 months after the 2nd surgery revealed non-union in ungrafted defects whereas grafted defects showed bone healing. The induced membrane had blood vessels, CBFA1 þ cells, and very few macrophages entrapped in a collagenous tissue positive for type I collagen. Conclusion-This ovine metatarsal defect model resulted in a critical-size defect (non-union) that healed when grafted. The PMMA-induced membrane constrained the graft, was well vascularized, and may have osteogenic properties. Clinical Relevance-This model may be useful to evaluate new strategies in bone tissue engineering because the PMMA-induced membrane may help confine bone morphogenetic proteins, skeletal stem cells, or other agents to the defect cavity where they could be useful to enhance bone formation.

Research paper thumbnail of A Fistula Flap Technique for Correction of Type II Atresia Ani and Rectovaginal Fistula in 6 Kittens

Veterinary Surgery, 2012

To report a surgical technique and long-term outcomes of type II atresia ani (AA) and rectovagina... more To report a surgical technique and long-term outcomes of type II atresia ani (AA) and rectovaginal fistula (RvF) correction, using a fistula flap technique in kittens. Clinical study. Domestic shorthaired female kittens (n = 6) with type II AA-RvF. Diagnosis of type II AA-RvF was made by clinical examination and vaginography. The anomaly was surgically corrected by a fistula flap technique for reconstruction of the anal canal and anus, and by vaginoplasty. Kittens were monitored for short and long-term complications. All 6 kittens were fecal and urinary continent in the immediate postoperative period. Postoperative complications occurred in 2 kittens: partial dehiscence between the anal and vaginal opening and a stenosis at the level of the rectal mucocutaneous anastomosis. Dehiscence healed by second intention and stenosis was treated by anoplasty. No long-term complications (median follow-up, 12 months; range, 12-17 months) were observed. Reconstruction of the anal canal and anus using the fistula as a local flap in combination with a vaginoplasty can be effective to treat feline type II AA and RvFs.

Research paper thumbnail of Preoperative Immunosuppressive Therapy and Surgery as a Treatment for Anal Furunculosis

Veterinary Surgery, 2006

Objectives-To evaluate the efficacy of combining preoperative immunosuppressive therapy with surg... more Objectives-To evaluate the efficacy of combining preoperative immunosuppressive therapy with surgical excision for treatment of anal furunculosis (AF) in dogs. Study Design-Retrospective study. Animals-Dogs (n ¼ 25) with stages 1-4 AF. Methods-Preoperative immunosuppressive therapy was either cyclosporine A (CyA) alone or in combination with ketoconazole (Group 1; n ¼ 18), or azathioprine combined with prednisolone (Group 2; n ¼ 7). Surgical excision of residual draining tracts, cryptectomy, and anal sacculectomy were performed. Only dogs with postoperative clinical follow-up exceeding 9 months were retained for the study. Results-Both immunosuppressive protocols were effective in reducing progression of AF. Subsequent draining tracts excision, cryptectomy, and anal sacculectomy were bilateral (12 dogs) or unilateral (13 dogs of which 4 had bilateral anal sacculectomy). Postoperative recovery was uneventful, except for 2 dogs that had wound breakdown. Recurrence was not observed in any of the dogs that had bilateral surgical excision and or in 9 dogs that had unilateral excision. Conclusion-Preoperative immunosuppressive therapy, combined with bilateral surgical resection of affected tissue consistently, resulted in resolution of AF. Four dogs that had recurrence had unilateral excision despite initial bilateral involvement, suggesting that all diseased tissue should be excised. Clinical Relevance-These preliminary results suggest that immunosuppressive therapy before surgical excision for AF yields minimizes recurrence in dogs.

Research paper thumbnail of A Perfusion Bioreactor for Engineering Bone Constructs: An In Vitro and In Vivo Study

Tissue Engineering Part C: Methods, 2011

Research paper thumbnail of A Novel Murine Femoral Segmental Critical-Sized Defect Model Stabilized by Plate Osteosynthesis for Bone Tissue Engineering Purposes

Tissue Engineering Part C: Methods, 2013

Research paper thumbnail of Bone Regeneration in Sheep UsingAcroporaCoral, a Natural Resorbable Scaffold, and Autologous Mesenchymal Stem Cells

Tissue Engineering Part A, 2013

Tissue constructs containing mesenchymal stem cells (MSC) are an appealing strategy for repairing... more Tissue constructs containing mesenchymal stem cells (MSC) are an appealing strategy for repairing massive segmental bone defects. However, their therapeutic effectiveness does not match that of autologous bone grafts; among the complicating reasons, the scaffold resorbability has been identified as a critical feature for achieving bone regeneration. In the present study, the osteogenic potential of constructs obtained by expanding autologous MSC onto granules of Acropora coral, a natural fully-resorbable scaffold, was investigated. MSC adhered and proliferated well in vitro after 1 week. When implanted in vivo into long-bone, critical-size defects in sheep (n = 5), these constructs exhibited a twofold increase in bone formation 6 months postimplantation compared to Acropora scaffolds alone (n = 5). Interestingly, osteogenesis, mediated by MSC, within these constructs was found continuous not only with the bony stumps, but also at the core of the implants. Scaffold resorption was almost complete at 6 months, leading to full bone regeneration in one animal. Acropora coral appear to be an appealing scaffold for bone tissue engineering because it supported in vitro MSC adhesion and proliferation. Moreover, these results provided evidence that MSC could promote bone regeneration in sheep when loaded one a natural fully resorbable scaffold.

Research paper thumbnail of De Novo Reconstruction of Functional Bone by Tissue Engineering in the Metatarsal Sheep Model

Tissue Engineering, 2005

Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone de... more Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone defect with a clinically relevant volume was efficiently reconstructed by transplanting an engineered bone in which mesenchymal stem cells (MSCs) expanded in autologous serum (AS) were combined with a porous scaffold. In the first step, we established that the way in which the MSCs are distributed over the scaffold affects the ultimate bone-forming ability of the transplant: constructs consisting of a natural coral scaffold and a pseudo-periosteal layer of MSCs surrounding the implant (coral-MSC3D) formed significantly more bone than constructs in which the MSCs were distributed throughout the implant (p ‫؍‬ 0.01). However, bone healing occurred in only one sheep, owing to the high resorption rate of natural coral scaffold. To overcome this problem, constructs in which MSCs were combined with a porous coralline-based hydroxyapatite (CHA) scaffold having the same architecture as natural coral but a lower resorption rate were prepared. After their implantation, these constructs were found to have the same osteogenic potential as autologous bone grafts in terms of the amount of newly formed bone present at 4 months (p ‫؍‬ 0.89) and to have been completely replaced by newly formed, structurally competent bone within 14 months. Nevertheless, although the rate of bone healing was strikingly improved when CHA-MSC3D constructs were used (five of seven animals healed) as compared with the coral-MSC3D construct (one of seven healed), it was still less satisfactory than that obtained with autografts (five of five healed).

Research paper thumbnail of La Vascularisation Osseuse Du Segment Intermediaire Dans Les Transferts Osseux Selon Ilizarov (Etude Experimentale Chez La Brebis)

MAISONS-ALFORT-Ecole Vétérin (940462302) / SudocSudocFranceF

Research paper thumbnail of Tissue-engineered bone regeneration

Nature Biotechnology, 2000

Research paper thumbnail of Biomechanical evaluation of a bioactive artificial anterior cruciate ligament

Advances in biomechanics and applications, 2014

This study aimed to assess the biomechanical performance of a new generation of artificial ligame... more This study aimed to assess the biomechanical performance of a new generation of artificial ligament, which can be considered "bioactive" and "biointegrated," implanted in sheep. Thirty sheep were implanted: 15 sheep received the artificial ligament grafted with a bioactive polymer (grafted) and 15 received the artificial ligament without a bioactive polymer (non-grafted). The animals were sacrificed 3 or 12 months after implantation. The knee kinematics, namely flexion-extension, anterior drawer, and varusvalgus tests, were evaluated using a fully characterized custom-made device. Afterward, the specimens were tested under uniaxial tension until failure. The flexion-extension showed significant differences between (grafted or non-grafted) artificial and native ligaments 3 months after implantation. This difference became non-significant 12 months postoperatively. The anterior tibial drawer was significantly increased 3 months after implantation and remained significantly different only for non-grafted ligament 12 months after implantation. Twelve months after implantation, the differences between grafted and non-grafted ligament biomechanical properties were significant in terms of stiffness. In terms of load to failure, grafted ligaments seem to have had slightly better performance than non-grafted ligaments 12 months postoperatively. Overall these results suggest that grafted artificial ligaments have slightly better biomechanical characteristics than non-grafted artificial ligaments 12 months after implantation in sheep.

Research paper thumbnail of Bone tissue response induced by bioactive polymer functionalized Ti6Al4V surfaces: In vitro and in vivo study

Journal of colloid and interface science, Jan 18, 2016

Ti6Al4V is commonly used for orthopedic applications. This study was designed to test the potenti... more Ti6Al4V is commonly used for orthopedic applications. This study was designed to test the potentially added benefit of Ti6Al4V functionalized with a bioactive polymer poly(sodium styrene sulfonate) both in vitro and in vivo. Cell-based assays with MC3T3-E1 osteoblast-like cells were used to measure the cell adhesion strength, cell spreading, focal contact formation, cell differentiation and the mineralization of extracellular matrix on grafted and ungrafted Ti6Al4V discs in combination with FBS and collagen type I. Bone morphogenetic protein-2 (BMP-2) was also included in the cell differentiation assay. Results showed that the grafted surface combined with collagen I gave superior levels in every parameter tested with cell-based assays and was almost equivalent to BMP-2 for cell differentiation. In vivo testing was conducted in rabbits (n=42) with cylinders of grafted and ungrafted Ti6Al4V implanted in defects made to the femoral and lateral condyles and animals that were maintained...

Research paper thumbnail of Reconstruction De Perte De Substance Osseuse Massive Par La Procédure De Masquelet : Modèle Expérimental Chez La Brebis

Journal of Bone Joint Surgery British Volume, Jul 1, 2008

Purpose of the study: The objective of this study was to establish an experimental sheep model fo... more Purpose of the study: The objective of this study was to establish an experimental sheep model for a surgical procedure which has been clinically successful for repairing major loss of bone stock: the Masquelet technique. Material and methods: A 25 mm bone defect was created in a metatarsal bone then filled with a cement filler. After six weeks, the cement was removed after opening the neoformed pseudosynovial membrane. The cavity was left empty in group 1 (n=6) or filled with a morcelized cancellous autograft harvested from the iliac crests in group 1 (n=6). Results: The surgery was well tolerated in all animals which were able to used the injured limb the day after the operation. Radiographic images and histological findings 24 weeks after surgery demonstrated that healing had not been achieved in all of the animals in group 1. Inversely, healing was achieved in all animals in group 2 at 24 weeks. Immunohistochemistry of the neoformed pseudosynovial demonstrated : an abundant vascular network, presence of cells expressing transcription factor CBFA1, very few inflammatory CD14+ cells (macrophages), an extracellular matrix positive for type I collagen. Conclusion: The sheep metatarsal model is a model of critical size with low morbidity. This model could be used to: evaluate new therapeutic strategies for bone regeneration in conditions close to clinical situations, study the role of the membrane in bone repair. The presence of a pseudosynovial membrane might: be a barrier against the diffusion of bone morphogenetic proteins outside the lesion and potentially be a reservoir of stem and vascular cells which could be useful for new technologies.

Research paper thumbnail of �valuation Clinique et Biologique D�un Ligament Synth�tique Bioactif Chez La Brebis

Research paper thumbnail of Comparison of Survival and Osteogenic Ability of Human Mesenchymal Stem Cells in Orthotopic and Ectopic Sites in Mice

Tissue Engineering Part A, 2016

Research paper thumbnail of 250. Effects of RH-BMP-2 (Inductos) on the Bone Healing Phase of a Distraction Osteogenesis Model

Journal of Bone Joint Surgery British Volume, Nov 1, 2011

Purpose of the study: The process of bone lengthening involves three phases: a latence period, di... more Purpose of the study: The process of bone lengthening involves three phases: a latence period, distraction, then healing. The healing phase required stability maintained by an external fixator (EF) for 1.16 months/cm lengthening. This time exposes the patient to serious complications. The objective is to accelerate the healing phase in order to shorten the time the patient has to wear the EF. The effect of BMP on osteogenesis in distraction remains a controversial issue. This work was conducted to evaluate the benefit provided by rhBMP-2 for healing the regenerate bone after distraction. Material and methods: Thirty-nine subadult male rabbits were selected at random. On day 0, a tibial osteotomy was performed followed by installation of a M101 EF. After the latency period of seven days, the distraction began at the rate of 0.5mm/12 h for 21 days. At day 28, at the end of distraction, a new operation was performed and three groups of 13 individuals were created at random. The first group received no material, the second a collagen type 1 sponge, and the third group a collagen type 1 sponge soaked in 100 μg/kg rhBMP-2. The animals were monitored with x-rays, absorptiometry and ultrasound for the qualitative and quantitative analysis. Histological and biomechanical analyses were performed at two months. Results: Our complication rate was 41%. Qualitative analysis of the x-rays showed, in group 3, the development of more or less voluminous and dense, sometimes hypertrophic calluses. The progression curves of the bone mineral content showed higher values in group 3. The bone mineral content curves remained nevertheless parallel for the three groups. The calluses were thus denser in group 3 but with an early peak density. Groups 1 and 2 had equivalent radiographic and absorptiometric results. The statistical analysis of the imaging findings is ongoing. The histology and biomechanical exams are being performed. Discussion: The preliminary results show that rhBMP-2 used early in the healing phase enables formation of more dense and hypertrophic calluses. rhBMP-2 does not acceleration the rate of callus formation but stimulates its mineralization. Use of a collagen sponge alone had no effect on healing. Analysis of the histological and mechanic properties observed in the three groups will provide a more precise description of the hypertrophic and strongly mineralized calluses. Conclusion: Our early results show superior bone mineralization in the treated group.

Research paper thumbnail of Traitement chirurgical d'une fracture vertébrale lombaire

Le Point Veterinaire Revue D Enseignement Post Universitaie Et De Formation Permanente, 2010

Chez le chien, les fractures vertebrales lombaires sont presque toujours secondaires a un acciden... more Chez le chien, les fractures vertebrales lombaires sont presque toujours secondaires a un accident de la voie publique et souvent associees a d'autres atteintes lesionnelles. Le scanner revet un interet particulier dans le bilan lesionnel de ces fractures et le choix du traitement. La presence d'une instabilite vertebrale necessite une reduction et une stabilisation chirurgicales. Le choix de la technique repose alors sur des criteres anatomiques et biomecaniques.

Research paper thumbnail of A New, Segmental, Critical-Size Defect Model for Long Bones: A Sheep Study

Key Engineering Materials, 2006

Introduction Reconstruction of large segmental bone defects can be achieved by a two-steps proced... more Introduction Reconstruction of large segmental bone defects can be achieved by a two-steps procedure using cancellous bone chips as described by Masquelet et al. In a first surgical procedure a PMMA-cement spacer is inserted into the defect. The presence of this foreign body triggers the formation of a pseudo-synovial membrane. After 8 weeks, the cement spacer is removed leaving a cavity surrounded by a membrane. This cavity is then filled with autologous cancellous (ACG) graft. Successful repairs of bone losses up to 25 cm long have been reported in human with this technique. It, however, requires large quantities of autograft and, sometimes successive surgeries need to be performed to achieve bone union. The discovery of growth factors and skeletal stem cells have opened new avenues for designing highly efficient bone substitutes. A key step in the development of these novel biomaterials is their in vivo assessment in clinically relevant animal models. In the present study, we set up a animal model that mimicked the surgical procedure described by Masquelet and explore the possibility of using skeletal stem cells loaded onto a coral scaffolds to repair such defects. Materials and Methods MSCs amplification: MSCs are expanded in 10% FCS with osteogenic supplements. Surgical model: 20 adult sheep underwent a 2.5 cm long mid diaphyseal bone resection of the metatarsus that was filled with a cement spacer for 6 weeks. At that time cement was carefully removed through an incision made along the formed pseudo-synovial membrane and replaced according the following protocols: Experimental groups Control groups: Defects left empty (n=4) or filled either with coral cubes (n=5) or autologous cancellous bone chips (n=5) harvested at the iliac crest were implanted as controls.Coral+MSCs group: constructs are composed of MSCs loaded onto natural coral cubes 3mm (n=7). Cells are loaded onto the scaffold 15 days prior to implantation and cultured under dynamic conditions. Animals were anaesthetized and radiographed every 4 weeks until they were sacrified, by intravenous barbiturate overdose, 24 weeks after surgery. Results Establishment of the animal model recherche médicale as well as the CNRS and l'INSERM. Reference: Masquelet AC, Fitoussi F, Begue T, et al. [Reconstruction of the long bones by the induced membrane and spongy autograft]. Ann

Research paper thumbnail of Corpectomie vidéo-assistée (CVA) : étude cadavérique et résultats cliniques préliminaires

Pratique Médicale et Chirurgicale de l'Animal de Compagnie, 2011

Research paper thumbnail of Animal Models for Bone Tissue Engineering Purposes

Sourcebook of Models for Biomedical Research

Page 1. 725 74 Animal Models for Bone Tissue Engineering Purposes VÉRONIQUE VIATEAU, DELPHINE LOG... more Page 1. 725 74 Animal Models for Bone Tissue Engineering Purposes VÉRONIQUE VIATEAU, DELPHINE LOGEART-AVRAMOGLOU, GENEVIÈVE GUILLEMIN, AND HERVÉ PETITE ABSTRACT To assess the efficacy of engineered ...

Research paper thumbnail of Animal Models for Orthopedic Applications of Tissue Engineering

Migonney/Biomaterials, 2014

Research paper thumbnail of Induction of a Barrier Membrane to Facilitate Reconstruction of Massive Segmental Diaphyseal Bone Defects: An Ovine Model

Veterinary Surgery, 2006

Objectives-To report an ovine model that can be used to evaluate the efficacy of bone substitutes... more Objectives-To report an ovine model that can be used to evaluate the efficacy of bone substitutes for repair of segmental diaphyseal bone defects. Study Design-Experimental study. Animals-Eleven 2-year-old Pre´-Alpes Sheep. Methods-Mid-diaphyseal metatarsal bone defects (25 mm long) were stabilized by a dynamic compression plate over a polymethylmethacrylate (PMMA) cement spacer, and by external coaptation. The PMMA spacer was removed at 6 weeks by incising the encapsulating membrane. The defect remained unfilled (Group 1; n ¼ 5) or was filled with morselized autologous corticocancellous graft (Group 2; n ¼ 6), the membrane sutured closed, and external coaptation applied for 6 months, when healing was evaluated. Results-Radiographic, computed tomographic, and histologic examinations at 6 months after the 2nd surgery revealed non-union in ungrafted defects whereas grafted defects showed bone healing. The induced membrane had blood vessels, CBFA1 þ cells, and very few macrophages entrapped in a collagenous tissue positive for type I collagen. Conclusion-This ovine metatarsal defect model resulted in a critical-size defect (non-union) that healed when grafted. The PMMA-induced membrane constrained the graft, was well vascularized, and may have osteogenic properties. Clinical Relevance-This model may be useful to evaluate new strategies in bone tissue engineering because the PMMA-induced membrane may help confine bone morphogenetic proteins, skeletal stem cells, or other agents to the defect cavity where they could be useful to enhance bone formation.

Research paper thumbnail of A Fistula Flap Technique for Correction of Type II Atresia Ani and Rectovaginal Fistula in 6 Kittens

Veterinary Surgery, 2012

To report a surgical technique and long-term outcomes of type II atresia ani (AA) and rectovagina... more To report a surgical technique and long-term outcomes of type II atresia ani (AA) and rectovaginal fistula (RvF) correction, using a fistula flap technique in kittens. Clinical study. Domestic shorthaired female kittens (n = 6) with type II AA-RvF. Diagnosis of type II AA-RvF was made by clinical examination and vaginography. The anomaly was surgically corrected by a fistula flap technique for reconstruction of the anal canal and anus, and by vaginoplasty. Kittens were monitored for short and long-term complications. All 6 kittens were fecal and urinary continent in the immediate postoperative period. Postoperative complications occurred in 2 kittens: partial dehiscence between the anal and vaginal opening and a stenosis at the level of the rectal mucocutaneous anastomosis. Dehiscence healed by second intention and stenosis was treated by anoplasty. No long-term complications (median follow-up, 12 months; range, 12-17 months) were observed. Reconstruction of the anal canal and anus using the fistula as a local flap in combination with a vaginoplasty can be effective to treat feline type II AA and RvFs.

Research paper thumbnail of Preoperative Immunosuppressive Therapy and Surgery as a Treatment for Anal Furunculosis

Veterinary Surgery, 2006

Objectives-To evaluate the efficacy of combining preoperative immunosuppressive therapy with surg... more Objectives-To evaluate the efficacy of combining preoperative immunosuppressive therapy with surgical excision for treatment of anal furunculosis (AF) in dogs. Study Design-Retrospective study. Animals-Dogs (n ¼ 25) with stages 1-4 AF. Methods-Preoperative immunosuppressive therapy was either cyclosporine A (CyA) alone or in combination with ketoconazole (Group 1; n ¼ 18), or azathioprine combined with prednisolone (Group 2; n ¼ 7). Surgical excision of residual draining tracts, cryptectomy, and anal sacculectomy were performed. Only dogs with postoperative clinical follow-up exceeding 9 months were retained for the study. Results-Both immunosuppressive protocols were effective in reducing progression of AF. Subsequent draining tracts excision, cryptectomy, and anal sacculectomy were bilateral (12 dogs) or unilateral (13 dogs of which 4 had bilateral anal sacculectomy). Postoperative recovery was uneventful, except for 2 dogs that had wound breakdown. Recurrence was not observed in any of the dogs that had bilateral surgical excision and or in 9 dogs that had unilateral excision. Conclusion-Preoperative immunosuppressive therapy, combined with bilateral surgical resection of affected tissue consistently, resulted in resolution of AF. Four dogs that had recurrence had unilateral excision despite initial bilateral involvement, suggesting that all diseased tissue should be excised. Clinical Relevance-These preliminary results suggest that immunosuppressive therapy before surgical excision for AF yields minimizes recurrence in dogs.

Research paper thumbnail of A Perfusion Bioreactor for Engineering Bone Constructs: An In Vitro and In Vivo Study

Tissue Engineering Part C: Methods, 2011

Research paper thumbnail of A Novel Murine Femoral Segmental Critical-Sized Defect Model Stabilized by Plate Osteosynthesis for Bone Tissue Engineering Purposes

Tissue Engineering Part C: Methods, 2013

Research paper thumbnail of Bone Regeneration in Sheep UsingAcroporaCoral, a Natural Resorbable Scaffold, and Autologous Mesenchymal Stem Cells

Tissue Engineering Part A, 2013

Tissue constructs containing mesenchymal stem cells (MSC) are an appealing strategy for repairing... more Tissue constructs containing mesenchymal stem cells (MSC) are an appealing strategy for repairing massive segmental bone defects. However, their therapeutic effectiveness does not match that of autologous bone grafts; among the complicating reasons, the scaffold resorbability has been identified as a critical feature for achieving bone regeneration. In the present study, the osteogenic potential of constructs obtained by expanding autologous MSC onto granules of Acropora coral, a natural fully-resorbable scaffold, was investigated. MSC adhered and proliferated well in vitro after 1 week. When implanted in vivo into long-bone, critical-size defects in sheep (n = 5), these constructs exhibited a twofold increase in bone formation 6 months postimplantation compared to Acropora scaffolds alone (n = 5). Interestingly, osteogenesis, mediated by MSC, within these constructs was found continuous not only with the bony stumps, but also at the core of the implants. Scaffold resorption was almost complete at 6 months, leading to full bone regeneration in one animal. Acropora coral appear to be an appealing scaffold for bone tissue engineering because it supported in vitro MSC adhesion and proliferation. Moreover, these results provided evidence that MSC could promote bone regeneration in sheep when loaded one a natural fully resorbable scaffold.

Research paper thumbnail of De Novo Reconstruction of Functional Bone by Tissue Engineering in the Metatarsal Sheep Model

Tissue Engineering, 2005

Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone de... more Large bone defects are still a challenge to orthopedic surgeons. In this study, a massive bone defect with a clinically relevant volume was efficiently reconstructed by transplanting an engineered bone in which mesenchymal stem cells (MSCs) expanded in autologous serum (AS) were combined with a porous scaffold. In the first step, we established that the way in which the MSCs are distributed over the scaffold affects the ultimate bone-forming ability of the transplant: constructs consisting of a natural coral scaffold and a pseudo-periosteal layer of MSCs surrounding the implant (coral-MSC3D) formed significantly more bone than constructs in which the MSCs were distributed throughout the implant (p ‫؍‬ 0.01). However, bone healing occurred in only one sheep, owing to the high resorption rate of natural coral scaffold. To overcome this problem, constructs in which MSCs were combined with a porous coralline-based hydroxyapatite (CHA) scaffold having the same architecture as natural coral but a lower resorption rate were prepared. After their implantation, these constructs were found to have the same osteogenic potential as autologous bone grafts in terms of the amount of newly formed bone present at 4 months (p ‫؍‬ 0.89) and to have been completely replaced by newly formed, structurally competent bone within 14 months. Nevertheless, although the rate of bone healing was strikingly improved when CHA-MSC3D constructs were used (five of seven animals healed) as compared with the coral-MSC3D construct (one of seven healed), it was still less satisfactory than that obtained with autografts (five of five healed).