Evaluación del VEGF en la medula ósea del hueso interradicular en animales tratados con olpadronato

Vascular endothelial growth factor (VEGF) is a protein that increases vascular permeability and induces the proliferation, migration and survival of endothelial cells. Bisphosphonates (BPs) are antiresorptive drugs that are widely used in the treatment of bone metabolism diseases and bone metastases. Since 2003, cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) have been reported. Few papers explain the mechanisms that induce BRONJ; some authors mention alterations in bone remodelling and a certain antiangiogenic effect of BPs. The aim of this study is to evaluate the expression of VEGF in bone marrow cells and the number of blood vessels and area occupied by them in animals treated with the BP sodium olpadronate (OPD). We used 16 Wistar rats, 60 days old, divided into two groups, experimental (OPD) and control. The OPD group received 0.3 mg/kg/week intraperitoneal OPD for 5 weeks. The control group received an equivalent intraperitoneal volume of physiological saline solution. After euthanasia, hemimandibles were processed and mesio-distal histological sections of the first molar were prepared. Sections were stained with hematoxylin-eosin (HE), immunohistochemical detection of VEGF was performed (sc7269) and the following histomorphometric parameters were evaluated: In HE-stained sections - number of blood vessels per sq. mm. and percentage (%) of area occupied by blood vessels in relation to total area evaluated; in sections with immunohistochemical detection of VEGF – number of VEGF+ bone marrow cells per sq. mm. Data underwent statistical analysis. Number of blood vessels/mm2 was significantly lower in the OPD group (OPD: 92 ± 16; Control: 140 ± 31; p<0.05) and % vascular area/ total area evaluated showed no significant difference (OPD: 15.6 ± 6.1; Control: 10.2 ± 4.2). Number of VEGF+ cells/mm2 was lower in the OPD group than in the control group, with statistically significant differences (OPD: 7804.8 ± 597; Control: 13187.6 ± 894; p<0.001). The results of this study suggest that monosodium olpadronate has an antiangiogenic effect. Further studies are needed to reveal its potential as an antitumor agent and its connection with the onset of BRONJ.El factor de crecimiento vascular (VEGF) es una proteína que incrementa la permeabilidad vascular, induce la proliferación, migración y supervivencia de las células endoteliales. Los bifosfonatos (BFs) son drogas antirresortivas ampliamente utilizadas en el tratamiento de enfermedades que alteran el metabolismo óseo y de metástasis óseas. Desde el 2003 se han reportado casos de osteonecrosis de maxilar asociada al uso de BFs (ONAB). Escasas publicaciones explican los mecanismos que inducen la ONAB, algunos autores mencionan las alteraciones en la remodelación ósea y un cierto efecto antiangiogénico de los BFs. El objetivo del presente trabajo es evaluar la expresión de VEGF en células de la médula ósea y el número y el área ocupada por vasos sanguíneos en animales tratados con el BF olpadronato monosódico (OPD). Se utilizaron 16 ratas Wistar de 60 días divididas en dos grupos, experimental (OPD) y control. El grupo OPD, recibió 0,3 mg/kg/sem de OPD vía IP, durante 5 semanas. El grupo control, recibió un volumen equivalente vía IP de solución fisiológica. Luego de practicada la eutanasia se obtuvieron las hemimandíbulas y se procesaron para obtener cortes histológicos mesio-distales del primer molar. Se realizó la coloración hematoxilina-eosina (HE) y la detección inmunohistoquímica de VEGF (sc-7269) y se evaluaron los siguientes parámetros histomorfométricos: En cortes con H&E: Número de vasos sanguíneos por mm2 y porcentaje (%) de área ocupada por los vasos sanguíneos en relación al área total evaluada; en cortes con la detección inmunohistoquímica de VEGF: Número de células medulares VEGF+ por mm2. Los datos fueron estadísticamente analizados. El N° vasos sanguíneos/mm2 fue significativamente menor en el grupo OPD (OPD: 92 ± 16; control: 140 ± 31; p<0,05) y el % área vascular/área total evaluada no mostró diferencias significativas (OPD: 15,6 ± 6.1; Control: 10.2 ± 4.2). El N° de células VEGF+/mm2 en el grupo OPD fue menor que en el grupo control con diferencias estadísticamente significativas (OPD: 7804,8 ± 597; Control: 13187,6 ± 894; p<0,001). Los resultados de este estudio sugieren que el olpadronato monosódico tiene un efecto antiangiogénico. Futuros estudios revelarán su potencial como agente antitumoral así como también su relación con la aparición de ONAB.Fil: Pujadas Bigi, María Montserrat. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; ArgentinaFil: Escudero, Natalia Daniela. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; ArgentinaFil: Ubios, Angela Matilde. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mandalunis, Patricia Mónica. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; Argentin

Bisphosphonates as Chelating Agents in Uranium Poisoning

The study of uranium toxicity is very important for public health in general and especially for workers involved in the processes of uranium mining and milling because of the immediate and/or mediate risks of exposure. Most available studies show unsuccessful attempts to eliminate uranium from target organs once the poisoning has occurred. Our group has managed to avoid damage to target organs (short-term kidney and long-term bone damage) in a high percentage of animals treated with lethal doses of uranyl nitrate through the effective chelating action of a single dose of bisodic etidronate. In this context, the contributions of our team and other groups working on chelating therapies provide a starting point for progress in the search for agents for preventing and/or reducing the toxic effects of uranium

Evaluación del VEGF en la medula ósea del hueso interradicular en animales tratados con olpadronato

Vascular endothelial growth factor (VEGF) is a protein that increases vascular permeability and induces the proliferation, migration and survival of endothelial cells. Bisphosphonates (BPs) are antiresorptive drugs that are widely used in the treatment of bone metabolism diseases and bone metastases. Since 2003, cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) have been reported. Few papers explain the mechanisms that induce BRONJ; some authors mention alterations in bone remodelling and a certain antiangiogenic effect of BPs. The aim of this study is to evaluate the expression of VEGF in bone marrow cells and the number of blood vessels and area occupied by them in animals treated with the BP sodium olpadronate (OPD). We used 16 Wistar rats, 60 days old, divided into two groups, experimental (OPD) and control. The OPD group received 0.3 mg/kg/week intraperitoneal OPD for 5 weeks. The control group received an equivalent intraperitoneal volume of physiological saline solution. After euthanasia, hemimandibles were processed and mesio-distal histological sections of the first molar were prepared. Sections were stained with hematoxylin-eosin (HE), immunohistochemical detection of VEGF was performed (sc7269) and the following histomorphometric parameters were evaluated: In HE-stained sections - number of blood vessels per sq. mm. and percentage (%) of area occupied by blood vessels in relation to total area evaluated; in sections with immunohistochemical detection of VEGF – number of VEGF+ bone marrow cells per sq. mm. Data underwent statistical analysis. Number of blood vessels/mm2 was significantly lower in the OPD group (OPD: 92 ± 16; Control: 140 ± 31; p<0.05) and % vascular area/ total area evaluated showed no significant difference (OPD: 15.6 ± 6.1; Control: 10.2 ± 4.2). Number of VEGF+ cells/mm2 was lower in the OPD group than in the control group, with statistically significant differences (OPD: 7804.8 ± 597; Control: 13187.6 ± 894; p<0.001). The results of this study suggest that monosodium olpadronate has an antiangiogenic effect. Further studies are needed to reveal its potential as an antitumor agent and its connection with the onset of BRONJ.El factor de crecimiento vascular (VEGF) es una proteína que incrementa la permeabilidad vascular, induce la proliferación, migración y supervivencia de las células endoteliales. Los bifosfonatos (BFs) son drogas antirresortivas ampliamente utilizadas en el tratamiento de enfermedades que alteran el metabolismo óseo y de metástasis óseas. Desde el 2003 se han reportado casos de osteonecrosis de maxilar asociada al uso de BFs (ONAB). Escasas publicaciones explican los mecanismos que inducen la ONAB, algunos autores mencionan las alteraciones en la remodelación ósea y un cierto efecto antiangiogénico de los BFs. El objetivo del presente trabajo es evaluar la expresión de VEGF en células de la médula ósea y el número y el área ocupada por vasos sanguíneos en animales tratados con el BF olpadronato monosódico (OPD). Se utilizaron 16 ratas Wistar de 60 días divididas en dos grupos, experimental (OPD) y control. El grupo OPD, recibió 0,3 mg/kg/sem de OPD vía IP, durante 5 semanas. El grupo control, recibió un volumen equivalente vía IP de solución fisiológica. Luego de practicada la eutanasia se obtuvieron las hemimandíbulas y se procesaron para obtener cortes histológicos mesio-distales del primer molar. Se realizó la coloración hematoxilina-eosina (HE) y la detección inmunohistoquímica de VEGF (sc-7269) y se evaluaron los siguientes parámetros histomorfométricos: En cortes con H&E: Número de vasos sanguíneos por mm2 y porcentaje (%) de área ocupada por los vasos sanguíneos en relación al área total evaluada; en cortes con la detección inmunohistoquímica de VEGF: Número de células medulares VEGF+ por mm2. Los datos fueron estadísticamente analizados. El N° vasos sanguíneos/mm2 fue significativamente menor en el grupo OPD (OPD: 92 ± 16; control: 140 ± 31; p<0,05) y el % área vascular/área total evaluada no mostró diferencias significativas (OPD: 15,6 ± 6.1; Control: 10.2 ± 4.2). El N° de células VEGF+/mm2 en el grupo OPD fue menor que en el grupo control con diferencias estadísticamente significativas (OPD: 7804,8 ± 597; Control: 13187,6 ± 894; p<0,001). Los resultados de este estudio sugieren que el olpadronato monosódico tiene un efecto antiangiogénico. Futuros estudios revelarán su potencial como agente antitumoral así como también su relación con la aparición de ONAB.Fil: Pujadas Bigi, María Montserrat. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; ArgentinaFil: Escudero, Natalia Daniela. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; ArgentinaFil: Ubios, Angela Matilde. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Mandalunis, Patricia Mónica. Universidad de Buenos Aires. Facultad de Odontología. Cátedra de Histología y Embriología; Argentin

Long term bone alterations in aged rats suffering type 1 diabetes

Increasing duration of type 1 diabetes mellitus alters bone metabolism. Clinical studies and experimental studies in long bones of rats with experimentally induced diabetes have reported a decrease in bone density. Few studies have explored this diabetes related alteration in the maxillae. Given that this finding could indicate the possible development of osteopenia in the maxilla in the long term, the present study sought to analyze alterations in alveolar bone in aged rats, 12, 18, and 24 weeks after inducing diabetes, and compare alveolar bone response to that of tibial subchondral bone at the same experimental times. Thirty-six male Wistar rats, 130 g body weight, were divided into 2 groups: an experimental group (E) receiving a single i.p. 60 mg/kg dose of streptozotocin, and a control group (C). Both the control and experimental groups were divided into 3 sub-sets, according to the time of euthanasia: 12, 18 and 24 weeks. The alveolar bone and tibiae were examined histologically and histomorphometrically. The results were analyzed using Student's t-test; a value of p < 0.05 was considered statistically significant. Results: Subchondral bone volume and bone activity/remodeling, mainly bone rest, were significantly lower in diabetic animals compared to controls, at both 12 and 18 weeks. No differences in alveolar bone parameters were observed between diabetic and control animals at either of the experimental times. Animals surviving at 24 weeks showed few trabeculae at rest and severe destruction of dental and periodontal tissues. The results of the present study show that diabetic osteopenia is evident in the tibia at 12 and at 18 weeks, whereas its effects on the maxilla can be seen at 24 weeks, with substantial destruction of alveolar bone and of the remaining periodontal and dental tissues. All the above observations highlight the need for preventive oral care in diabetic patients, before irreversible damage to dental and periodontal tissues occurs.Fil: Sánchez, Luciana Marina. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: de Lucca, Romina Carmen. Universidad de Buenos Aires. Facultad de Odontología; ArgentinaFil: Lewicki, Marianela. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ubios, Angela Matilde. Universidad de Buenos Aires. Facultad de Odontología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Experimental model of distraction osteogenesis in edentulous rats

Distraction osteogenesis (DO) is a surgical technique producing bone lengthening by distraction of the fracture callus. Although a large number of experimental studies on the events associated with DO of craniofacial skeleton have been reported, the few employing rat mandibular bone DO used complicated designs and produced a small volume of newly formed bone. Thus, this study aims to present an original experimental model of mandibular DO in edentulous rats that produces a sufficient quantity and quality of intramembranous bone. Eight male Wistar rats, weighing 75 g, underwent extraction of lower molars. With rats weighing 350 g, right mandibular osteotomy was performed and the distraction device was placed. The distraction device was custom made using micro-implants, expansion screws, and acrylic resin. Study protocol: latency: 6 days, distraction: ¼ turn (0.175 mm) once a day during 6 d, consolidation: 28 d after distraction phase, sacrifice. DO-treated and contralateral hemimandibles were dissected and compared macroscopically and using radiographic studies. Histological sections were obtained and stained with H&E. A distraction gap filled with newly formed and mature bone tissue was obtained. This model of mandibular DO proved useful to obtain adequate quantity and quality of bone to study bone regeneration