Osteogenic-angiogenic coupled response of cobalt-containing mesoporous bioactive glasses in vivo.

The incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of interest for bone regeneration purposes. In the present work, we have designed a set of bioactive mesoporous glasses SiO2-CaO-P2O5-CoO (Co-MBGs) with different amounts of cobalt. The physicochemical changes introduced by the Co2+ ion, the in vitro effects of Co-MBGs on preosteoblasts and endothelial cells and their in vivo behaviour using them as bone grafts in a sheep model were studied. The results show that Co2+ ions neither destroy mesoporous ordering nor inhibit in vitro bioactive behaviour, exerting a dual role as network former and modifier for CoO concentrations above 3 % mol. On the other hand, the activity of Co-MBGs on MC3T3-E1 preosteoblasts and HUVEC vascular endothelial cells is dependent on the concentration of CoO present in the glass. For low Co-MBGs concentrations (1mg/ml) cell viability is not affected, while the expression of osteogenic (ALP, RUNX2 and OC) and angiogenic (VEGF) genes is stimulated. For Co-MBGs concentration of 5 mg/ml, cell viability decreases as a function of the CoO content. In vivo studies show that the incorporation of Co2+ ions to the MBGs improves the bone regeneration activity of these materials, despite the deleterious effect that this ion has on bone-forming cells for any of the Co-MBG compositions studied. This contradictory effect is explained by the marked increase in angiogenesis that takes place inside the bone defect, leading to an angiogenesis-osteogenesis coupling that compensates for the partial decrease in osteoblast cells. STATEMENT OF SIGNIFICANCE: The development of new bone grafts implies to address the need for osteogenesis-angiogenesis coupling that allows bone regeneration with viable tissue in the long term. In this sense the incorporation of cobalt ions into the composition of bioactive glasses has emerged as a strategy of great interest in this field. Due to the potential cytotoxic effect of cobalt ions, there is an important controversy regarding the suitability of their incorporation in bone grafts. In this work, we address this controversy after the implantation of cobalt-doped mesoporous bioactive glasses in a sheep model. The incorporation of cobalt ions in bioactive glasses improves the bone regeneration ability of these bone grafts, due to enhancement of the angiogenesis-osteogenesis coupling.

Injectable mesoporous bioactive nanoparticles regenerate bone tissue under osteoporosis conditions.

The osteogenic capability of mesoporous bioactive nanoparticles (MBNPs) in the SiO2CaO system has been assessed in vivo using an osteoporotic rabbit model. MBNPs have been prepared using a double template method, resulting in spherical nanoparticles with a porous core-shell structure that has a high surface area and the ability to incorporate the anti-osteoporotic drug ipriflavone. In vitro expression of the pro-inflammatory genes NF-κB1, IL-6, TNF-α, P38 and NOS2 in RAW-264.7 macrophages, indicates that these nanoparticles do not show adverse inflammatory effects. An injectable system has been prepared by suspending MBNPs in a hyaluronic acid-based hydrogel, which has been injected intraosseously into cavitary bone defects in osteoporotic rabbits. The histological analyses evidenced that MBNPs promote bone regeneration with a moderate inflammatory response. The incorporation of ipriflavone into these nanoparticles resulted in a higher presence of osteoblasts and enhanced angiogenesis at the defect site, but without showing significant differences in terms of new bone formation. STATEMENT OF SIGNIFICANCE: Mesoporous bioactive glass nanoparticles have emerged as one of the most interesting materials in the field of bone regeneration therapies. For the first time, injectable mesoporous bioactive nanoparticles have been tested in vivo using an osteoporotic animal model. Our findings evidence that MBG nanoparticles can be loaded with an antiosteoporotic drug, ipriflavone, and incorporated in hyaluronic acid to make up an injectable hydrogel. The incorporation of MBG nanoparticles promotes bone regeneration even under osteoporotic conditions, whereas the presence of IP enhances angiogenesis as well as the presence of osteoblast cells lining in the newly formed bone. The injectable device presented in this work opens new possibilities for the intraosseous treatment of osteoporotic bone using minimally invasive surgery.

Development and assessment of an ex-vivo bench model aimed at laparoscopic ureteric reconstructive techniques.

INTRODUCTION/BACKGROUND: Reconstructive and ablative urologic techniques require special technical mastery, especially the intracorporeal suturing. OBJECTIVE: To report the subjective evaluation of a versatile ex-vivo model aimed to practice laparoscopic ureteric reconstructive techniques (LURT) on box-trainer. STUDY DESIGN: The model is a continuous portion of porcine urinary bladder ("dilated pelvis"), the vesico-ureteral joint ("stenosis") and healthy ureter. All 127 participants (n = 119 urologists and n = 8 paediatric surgeons) performed on the model laparoscopic Anderson-Hynes dismembered pyeloplasty, and then, in the animal model, different LURT procedures (ureteroneocystostomy, ureteric reimplantation and/or dismembered pyeloplasty). The model was subjectively evaluated (face and content validity), through a 12 items questionnaire, based on a Likert scale (1-5 points) and a global question (1-10 points). RESULTS: The total mean rating for 11/12 items was very high (>4points). Only one was rated under 3 points. The overall total mean rating from 1 to 10 points was very high (9.19 ± 0.82 points). In 10/12 items, expert's feedback (content validity) prevailed over non-experts (face validity). DISCUSSION/CONCLUSION: The model was highly accepted for the practice of LURT techniques. Additionally, it is cost-effective, easy to assemble, ethically considerate, and realistic.

Silicon substituted hydroxyapatite/VEGF scaffolds stimulate bone regeneration in osteoporotic sheep.

Silicon-substituted hydroxyapatite (SiHA) macroporous scaffolds have been prepared by robocasting. In order to optimize their bone regeneration properties, we have manufactured these scaffolds presenting different microstructures: nanocrystalline and crystalline. Moreover, their surfaces have been decorated with vascular endothelial growth factor (VEGF) to evaluate the potential coupling between vascularization and bone regeneration. In vitro cell culture tests evidence that nanocrystalline SiHA hinders pre-osteblast proliferation, whereas the presence of VEGF enhances the biological functions of both endothelial cells and pre-osteoblasts. The bone regeneration capability has been evaluated using an osteoporotic sheep model. In vivo observations strongly correlate with in vitro cell culture tests. Those scaffolds made of nanocrystalline SiHA were colonized by fibrous tissue, promoted inflammatory response and fostered osteoclast recruitment. These observations discard nanocystalline SiHA as a suitable material for bone regeneration purposes. On the contrary, those scaffolds made of crystalline SiHA and decorated with VEGF exhibited bone regeneration properties, with high ossification degree, thicker trabeculae and higher presence of osteoblasts and blood vessels. Considering these results, macroporous scaffolds made of SiHA and decorated with VEGF are suitable bone grafts for regeneration purposes, even in adverse pathological scenarios such as osteoporosis. STATEMENT OF SIGNIFICANCE: For the first time, the in vivo behavior of scaffolds made of silicon substituted hydroxyapatites (SiHA) has been evaluated under osteoporosis conditions. In order to optimize the bone regeneration properties of these bioceramics, 3D macroporous scaffolds have been manufactured by robocasting and implanted in osteoporotic sheep. Our experimental design shed light on the important issue of the biological response of nano-sized bioceramics vs highly crystalline bioceramics, as well as on the importance of coupling vascularization and bone growth processes by decorating SiHA scaffolds with vascular endothelial growth factor.

Validación de un nuevo modelo de simulación inorgánica para la anastomosis uretrovesical laparoscópica / Validation of a new artificial model for simulated training of a laparoscopic vesicourethral anastomosis

Objetivo: El objetivo de este estudio es demostrar la validez de un modelo inorgánico de bajo coste para el aprendizaje y entrenamiento de la anastomosis uretrovesical laparoscópica. Materiales y métodos: En este estudio participaron alumnos que asistieron a alguna de las ediciones de los cursos monográficos sobre prostatectomía radical laparoscópica (PRL) celebrados durante el periodo de 2015 a 2017. Estos participantes se dividieron en 2 grupos de acuerdo con su experiencia previa en cirugía laparoscópica (CL). Las tareas que realizaron sobre el simulador inorgánico fueron la resección de la próstata, "tarea 1" y la anastomosis uretrovesical, "tarea 2". Una vez realizados estos ejercicios, los participantes del estudio completaron un cuestionario anónimo donde se recogieron sus datos demográficos y su nivel de experiencia en CL. Además, los asistentes realizaron una valoración de la capacidad didáctica del órgano sintético empleado, evaluando su utilidad como herramienta para la formación específica de PRL. Para demostrar la validación aparente y de contenidos los participantes mostraron su opinión acerca de la textura, la consistencia, la morfología y la similitud del órgano con el paciente real. La valoración se realizó según una escala de Likert de 5 puntos. Resultados: Los alumnos se distribuyeron en 2 grupos: 10 expertos (grupo E) y 12 noveles (grupo N). La única diferencia significativa entre las puntuación de noveles y de expertos fue respecto a la inclusión de esta herramienta en los programas de formación (grupo E = 5 puntos frente al grupo N = 4,4 ± 0,59, p = 0,024). Los expertos calificaron todas las cuestiones con mayores puntaciones que los noveles. En cuanto a la valoración general del modelo inorgánico, los participantes noveles dieron una calificación media de 8,00±0,91 puntos sobre 10, siendo superada por la valoración de los participantes del grupo de expertos, que dieron una puntuación media de 9,4 ± 0,51. Conclusión: Este modelo inorgánico ha demostrado poseer validez aparente, de contenidos y constructiva, además de ser una herramienta didáctica ideal para el aprendizaje y el entrenamiento de la resección prostática y de la anastomosis uretrovesical laparoscópica

Objective: The aim of this study is to prove the effectiveness of a low cost, artificial model for training of a laparoscopic urethrovesical anastomosis. Materials and methods: This study included urologists who attended specialised courses on laparoscopic radical prostatectomy (LRP) held during the period 2015 to 2017. They were divided into 2 groups according to their previous experience in laparoscopic surgery. The tasks performed on the artificial simulator were prostate resection, "task 1", and urethrovesical anastomosis, "task 2". Once these exercises were completed, the study participants filled in an anonymous questionnaire regarding their demographic data and experience level in laparoscopic surgery (LS). In addition, they gave their opinions about the didactic capacity of the artificial organ and evaluated its usefulness as a tool for LRP training. To demonstrate face and content validity, the participants judged the texture, consistency, morphology and evaluated its similarity to the real organ. The assessment was made with a five-point Likert scale. Results: The students were divided into 2 groups: 10 experts (Group E) and 12 novices (Group N). The only significant difference between the scores of novices and experts was regarding the inclusion of this tool in the training programs (Group E = 5 points versus group N = 4.4 ± 0.59, P = .024). The experts' group rated all the items with higher scores than the novices’ one. Regarding the general assessment of the simulation model, the novice participants gave an average score of 8.00 ± 0.91 points out of 10, while the experts’ group granted higher scores of 9.4 ± 0,51. Conclusion: This artificial model has shown to have an elevated face, content and construct validity, as well being an optimal didactic tool for training in the techniques of prostate resection and laparoscopic urethrovesical anastomosis

Validation of a new artificial model for simulated training of a laparoscopic vesicourethral anastomosis. / Validación de un nuevo modelo de simulación inorgánica para la anastomosis uretrovesical laparoscópica.

OBJECTIVE: The aim of this study is to prove the effectiveness of a low cost, artificial model for training of a laparoscopic urethrovesical anastomosis. MATERIALS AND METHODS: This study included urologists who attended specialised courses on laparoscopic radical prostatectomy (LRP) held during the period 2015 to 2017. They were divided into 2 groups according to their previous experience in laparoscopic surgery. The tasks performed on the artificial simulator were prostate resection, "task 1", and urethrovesical anastomosis, "task 2". Once these exercises were completed, the study participants filled in an anonymous questionnaire regarding their demographic data and experience level in laparoscopic surgery (LS). In addition, they gave their opinions about the didactic capacity of the artificial organ and evaluated its usefulness as a tool for LRP training. To demonstrate face and content validity, the participants judged the texture, consistency, morphology and evaluated its similarity to the real organ. The assessment was made with a five-point Likert scale. RESULTS: The students were divided into 2groups: 10 experts (Group E) and 12 novices (Group N). The only significant difference between the scores of novices and experts was regarding the inclusion of this tool in the training programs (Group E=5 points versus group N=4.4±0.59, P=.024). The experts' group rated all the items with higher scores than the novices' one. Regarding the general assessment of the simulation model, the novice participants gave an average score of 8.00±0.91 points out of 10, while the experts' group granted higher scores of 9.4±0,51. CONCLUSION: This artificial model has shown to have an elevated face, content and construct validity, as well being an optimal didactic tool for training in the techniques of prostate resection and laparoscopic urethrovesical anastomosis.

Mesoporous bioactive glass/ɛ-polycaprolactone scaffolds promote bone regeneration in osteoporotic sheep.

Macroporous scaffolds made of a SiO2-CaO-P2O5 mesoporous bioactive glass (MBG) and ɛ-polycaprolactone (PCL) have been prepared by robocasting. These scaffolds showed an excellent in vitro biocompatibility in contact with osteoblast like cells (Saos 2) and osteoclasts derived from RAW 264.7 macrophages. In vivo studies were carried out by implantation into cavitary defects drilled in osteoporotic sheep. The scaffolds evidenced excellent bone regeneration properties, promoting new bone formation at both the peripheral and the inner parts of the scaffolds, thick trabeculae, high vascularization and high presence of osteoblasts and osteoclasts. In order to evaluate the effects of the local release of an antiosteoporotic drug, 1% (%wt) of zoledronic acid was incorporated to the scaffolds. The scaffolds loaded with zoledronic acid induced apoptosis in Saos 2 cells, impeded osteoclast differentiation in a time dependent manner and inhibited bone healing, promoting an intense inflammatory response in osteoporotic sheep. STATEMENT OF SIGNIFICANCE: In addition to an increase in bone fragility and susceptibility to fracture, osteoporosis also hinders the clinical success of endosseous implants and grafting materials for the treatment of bone defects. For the first time, macroporous scaffolds made of mesoporous bioactive glass and ε-caprolactone have been evaluated in a sheep model that mimics the osteoporosis conditions in humans. These implants fostered bone regeneration, promoting new bone formation at both the peripheral and the inner parts of the scaffolds, showing thick trabeculae and a high vascularization degree. Our results indicate that macroporous structures containing highly bioactive mesoporous glasses could be excellent candidates for the regenerative treatment of bone defects in osteoporotic patients.

Synergistic effect of Si-hydroxyapatite coating and VEGF adsorption on Ti6Al4V-ELI scaffolds for bone regeneration in an osteoporotic bone environment.

The osteogenic and angiogenic responses to metal macroporous scaffolds coated with silicon substituted hydroxyapatite (SiHA) and decorated with vascular endothelial growth factor (VEGF) have been evaluated in vitro and in vivo. Ti6Al4V-ELI scaffolds were prepared by electron beam melting and subsequently coated with Ca10(PO4)5.6(SiO4)0.4(OH)1.6 following a dip coating method. In vitro studies demonstrated that SiHA stimulates the proliferation of MC3T3-E1 pre-osteoblastic cells, whereas the adsorption of VEGF stimulates the proliferation of EC2 mature endothelial cells. In vivo studies were carried out in an osteoporotic sheep model, evidencing that only the simultaneous presence of both components led to a significant increase of new tissue formation in osteoporotic bone. STATEMENT OF SIGNIFICANCE: Reconstruction of bones after severe trauma or tumors extirpation is one of the most challenging tasks in the field of orthopedic surgery. This scenario is even more complicated in the case of osteoporotic patients, since their bone regeneration capability is decreased. In this work we present a porous implant that promotes bone regeneration even in osteoporotic bone. By coating the implant with osteogenic bioceramics such as silicon substituted hydroxyapatite and subsequent adsorption of vascular endothelial growth factor, these implants stimulate the bone ingrowth when they are implanted in osteoporotic sheep.