Morphometric study of the porcine placental vascularization.

The early development in mammals is characterized by the contribution of nutrients from the maternal tissues through the placenta, which is in apposition with foetal membranes and the endometrium, allowing the physiological interchange between the embryos/foetuses and the mother. The aim of this work was to study the number of placental blood vessels and their vascular area through morphometric analyses and the haemotrophic diffusion distance in porcine placental tissues from early gestations, intermediates gestations, advanced gestations and term gestations. For those purposes, morphometric measurements, blood vessel quantification, high-resolution light microscopy and transmission electron microscopy were performed. The implementation of the high-resolution light microscopy allowed studying the placental vascular and tissue histoarchitecture with higher definition and resolution than using a conventional light microscopy. We highlight the close location of the subepithelial capillaries to the maternal/foetal interface as pregnancy progresses. We found statistically significant evidence to state that the area of blood vessels is dependent on the gestation period. In advanced gestations, the presence of numerous small blood vessels and its near location to foetal/maternal interface agree with the great remodelling reported in our previous studies. In conclusion, in gilts, given the type of non-invasive epithelial placentation, the new blood vessels generation and of haemotrophic diffusion distance reduction, determined in this report, assure the maternal/foetal haemotrophic exchange efficiency during gestation.

Mecanismos de tumorogénesis hipofisaria: Estudio de factores angiogénicos y de proliferación / Mechanisms of Pituitary Tumorigenesis: Study of Angiogenic and Proliferation factors

Introducción y Objetivos: La angiogénesis es un proceso fundamental en el desarrollo tumoral. Sin embargo, se han encontrado discrepancias en el patrón angiogénico de los tumores hipofisarios. Nos propusimos estudiar la expresión de VEGF y FGF2 y su importancia en la vascularización de los adenomas hipofisarios, cuantificar los vasos con los marcadores CD31 y CD34 y determinar el índice de proliferación con PCNA y Ki67. Materiales y Métodos: Se estudiaron 76 macroadenomas hipofisarios que fueron intervenidos quirúrgicamente. Los adenomas se clasificaron según su secreción hormonal. A partir de cortes histológicos se realizó inmunohistoquímica para los marcadores de endotelio CD31 y CD34; y Ki-67 para estudio de proliferación celular. Por western blot se midieron VEGF, CD31 y PCNA. Se efectuaron comparaciones con glándulas normales. Resultados: El nivel de expresión de VEGF, hallado en todas las muestras analizadas, resultó mayor en los prolactinomas resistentes respecto a los demás tipos de adenomas hipofisarios. Esta proteína localizó en las células endoteliales de los vasos como así también en citoplasmas y núcleos de células tumorales. El 56 % de las muestras resultaron positivas para FGF2, mostrando localización citoplasmática y en matriz extracelular. Obtuvimos una fuerte correlación positiva entre VEGF y CD31 en las muestras tumorales, sin encontrar correlación lineal entre PCNA y VEGF, ni Ki-67 y VEGF en las muestras estudiadas. El área vascular resultó mayor en los tejidos normales que en los tumores utilizando CD34 como marcador de vasos. Conclusión: La importancia del estudio de la angiogénesis en los adenomas hipofisarios radica en la necesidad de hallar marcadores moleculares que predigan el comportamiento tumoral. Pudimos demostrar la expresión de los factores angiogénicos VEGF y FGF2 en estos adenomas, y la existencia de correlación lineal entre VEGF y CD31. Nuestros resultados son indicativos de existencia de angiogénesis en los adenomas hipofisarios por lo que su bloqueo podría plantearse como una estrategia alternativa para los casos resistentes a las terapias convencionales.

Introduction and objectives: Angiogenesis is an essential process in tumor development. Nevertheless, discrepancies in the angiogenic pattern of pituitary tumors, in terms of hormonal phenotype, size or invasiveness have been found. Our aim was to study the expression of VEGF and FGF2 growth factors, and their importance in the vascularization of pituitary adenomas. We also quantified blood vessels with the endothelial cell markers CD31 and CD34 determining the vascular area, and the proliferation rate through PCNA and Ki67 index. Materials and Methods: We studied 76 pituitary macroadenomas that were surgically resected in the period between 2006 and 2010 from a total of 276 patients with this pathology. Adenomas were classified into prolactinomas (PRL), somatotropinomas (GH), corticotropinomas (ACTH), non-functioning (NF) and plurihormonal (Ph) according to their hormonal secretion. Samples were collected in formalin, embedded in paraffin, and immunohistochemistry was performed from histological sections for endothelial markers CD31 and CD34; and for Ki-67 to study cell proliferation. VEGF, CD31 and PCNA were measured by Western blot. We compared results with normal glands (N=6). Results: VEGF expression levels, found in all of the samples analyzed, were higher in resistant prolactinomas than in other pituitary adenomas. This protein was detected in endothelial cells of blood vessels and in tumor cells cytoplasms and nuclei. Fifty-six percent of samples were positive for FGF2, the other potent angiogenic factor studied, showing cytoplasmatic and extracellular matrix localization. We obtained a strong positive correlation between VEGF and CD31 in tumor samples, but we did not find lineal correlation between PCNA and VEGF, or between Ki-67 and VEGF in the samples studied. The vascular area was higher in normal tissues than in tumors when CD34 was used as endothelial cell marker. Conclussion: The importance of studying angiogenesis in pituitary adenomas lies in the need to find molecular markers that can predict tumor behavior. We could demonstrate the expression of VEGF and FGF2, two potent angiogenic factors, and the existence of linear correlation between VEGF and CD31. Our results are indicative of the existence of angiogenesis in pituitary adenomas; therefore the blockage of angiogenesis might be proposed as an alternative strategy for cases of resistance to standard therapy.

Mecanismos de tumorogénesis hipofisaria: Estudio de factores angiogénicos y de proliferación / Mechanisms of Pituitary Tumorigenesis: Study of Angiogenic and Proliferation factors

Introducción y Objetivos: La angiogénesis es un proceso fundamental en el desarrollo tumoral. Sin embargo, se han encontrado discrepancias en el patrón angiogénico de los tumores hipofisarios. Nos propusimos estudiar la expresión de VEGF y FGF2 y su importancia en la vascularización de los adenomas hipofisarios, cuantificar los vasos con los marcadores CD31 y CD34 y determinar el índice de proliferación con PCNA y Ki67. Materiales y Métodos: Se estudiaron 76 macroadenomas hipofisarios que fueron intervenidos quirúrgicamente. Los adenomas se clasificaron según su secreción hormonal. A partir de cortes histológicos se realizó inmunohistoquímica para los marcadores de endotelio CD31 y CD34; y Ki-67 para estudio de proliferación celular. Por western blot se midieron VEGF, CD31 y PCNA. Se efectuaron comparaciones con glándulas normales. Resultados: El nivel de expresión de VEGF, hallado en todas las muestras analizadas, resultó mayor en los prolactinomas resistentes respecto a los demás tipos de adenomas hipofisarios. Esta proteína localizó en las células endoteliales de los vasos como así también en citoplasmas y núcleos de células tumorales. El 56 % de las muestras resultaron positivas para FGF2, mostrando localización citoplasmática y en matriz extracelular. Obtuvimos una fuerte correlación positiva entre VEGF y CD31 en las muestras tumorales, sin encontrar correlación lineal entre PCNA y VEGF, ni Ki-67 y VEGF en las muestras estudiadas. El área vascular resultó mayor en los tejidos normales que en los tumores utilizando CD34 como marcador de vasos. Conclusión: La importancia del estudio de la angiogénesis en los adenomas hipofisarios radica en la necesidad de hallar marcadores moleculares que predigan el comportamiento tumoral. Pudimos demostrar la expresión de los factores angiogénicos VEGF y FGF2 en estos adenomas, y la existencia de correlación lineal entre VEGF y CD31. Nuestros resultados son indicativos de existencia de angiogénesis en los adenomas hipofisarios por lo que su bloqueo podría plantearse como una estrategia alternativa para los casos resistentes a las terapias convencionales.(AU)

Introduction and objectives: Angiogenesis is an essential process in tumor development. Nevertheless, discrepancies in the angiogenic pattern of pituitary tumors, in terms of hormonal phenotype, size or invasiveness have been found. Our aim was to study the expression of VEGF and FGF2 growth factors, and their importance in the vascularization of pituitary adenomas. We also quantified blood vessels with the endothelial cell markers CD31 and CD34 determining the vascular area, and the proliferation rate through PCNA and Ki67 index. Materials and Methods: We studied 76 pituitary macroadenomas that were surgically resected in the period between 2006 and 2010 from a total of 276 patients with this pathology. Adenomas were classified into prolactinomas (PRL), somatotropinomas (GH), corticotropinomas (ACTH), non-functioning (NF) and plurihormonal (Ph) according to their hormonal secretion. Samples were collected in formalin, embedded in paraffin, and immunohistochemistry was performed from histological sections for endothelial markers CD31 and CD34; and for Ki-67 to study cell proliferation. VEGF, CD31 and PCNA were measured by Western blot. We compared results with normal glands (N=6). Results: VEGF expression levels, found in all of the samples analyzed, were higher in resistant prolactinomas than in other pituitary adenomas. This protein was detected in endothelial cells of blood vessels and in tumor cells cytoplasms and nuclei. Fifty-six percent of samples were positive for FGF2, the other potent angiogenic factor studied, showing cytoplasmatic and extracellular matrix localization. We obtained a strong positive correlation between VEGF and CD31 in tumor samples, but we did not find lineal correlation between PCNA and VEGF, or between Ki-67 and VEGF in the samples studied. The vascular area was higher in normal tissues than in tumors when CD34 was used as endothelial cell marker. Conclussion: The importance of studying angiogenesis in pituitary adenomas lies in the need to find molecular markers that can predict tumor behavior. We could demonstrate the expression of VEGF and FGF2, two potent angiogenic factors, and the existence of linear correlation between VEGF and CD31. Our results are indicative of the existence of angiogenesis in pituitary adenomas; therefore the blockage of angiogenesis might be proposed as an alternative strategy for cases of resistance to standard therapy.(AU)