comision de investigaciones
científicas de la provincia de
buenos aires
INFORME CIENTÍFICO-TECNOLÓGICO[1]
PERIODO: 2001-2002
Legajo Nº:
1.
APELLIDO: Gómez Dumm
NOMBRES: César Leandro Alberto
2.
TEMA
DE INVESTIGACION
Histofisiología del páncreas endocrino y
adenohipófisis bajo diversas condiciones experimentales.
3.
DATOS
RELATIVOS A INGRESO Y PROMOCIONES EN LA CARRERA
INGRESO: Categoría: Independiente
Mes: Año: 1979
ACTUAL: Categoría: Principal desde el mes: abril Año: 1993
4.
INSTITUCION
DONDE DESARROLLA LA TAREA
Nombre: Cátedra
de Histología y Embriología "B" y CENEXA
Dependencia: Facultad de Ciencias Médicas, UNLP.
Dirección: Calle: 60 y 120 Nº. s/n
Ciudad: La Plata 1900 Pcia: Buenos Aires
Tel: 425-6735
Dirección
electrónica: clgomezd@atlas.med.unlp.edu.ar
Cargo que ocupa: Profesor Extraordinario Consulto.
(Ex Profesor Titular con Dedicación Exclusiva).
5.
DIRECTOR
DE TRABAJOS. (En el caso que corresponda)
Apellido y Nombres:
Dirección. Calle
Ciudad: Pcia:
Tel:
Dirección electrónica:
....................................................... ..................................................
Firma del Director (si corresponde)
Firma del Investigador
Fecha:
6.
EXPOSICION SINTETICA DE
LA LABOR DESARROLLADA EN EL PERIODO.
6.1
Estudio morfológico
de la adenohipófisis en monos desnutridos (Estudio colaborativo con CIGEBA, Fac de Cs Veterinarias, UNLP).
La desnutrición producida por una dieta baja en
proteínas determina reducción de la actividad hipofisaria. Se utilizaron monos Saimiri
sciureus sometidos durante 3 años a dieta hipoproteica (10%). Se efectuó un
análisis cuantitativo inmunohistoquímico y ultraestructural de la
adenohipófisi, así como la medición de componentes del neurocráneo y faciales.
En los animales desnutridos se pudieron comprobar cambios en parámetros
morfométricos indicativos de función disminuída en células somatotropas,
lactotropas, gonadotropas y tirotropas, correlacionados con alteraciones ultraestructurales
y con modificaciones de los patrones morfométricos cráneo-faciales.
6.2
Mecanismos del
aumento de masa celular B inducido por dieta rica en sacarosa.
El objetivo fue clarificar los mecanismos mediante los
cuales una dieta rica en sacarosa produce un aumento de la masa celular B en el
páncreas de la rata. Después de 30 semanas de tratamiento, se constató que
aunque el aumento de replicación de las células B (detección del PCNA) y la
disminución de la apoptosis jugarían un rol importante, la neogénesis insular
(citoqueratina 19) constituiría el mecanismo compensador decisivo en la
adaptación a la mayor demanda de insulina.
6.3
Trabajos colaborativos
con el IBYME (Bs As) y la Fac. de Cs. Veterinarias, UNLP.
6.3.1
Efecto de andrógenos
y antiandrógenos no esteroides (Casodex y flutamida) sobre células gonadotropas. Se estudiaron ratas machos prepuberales mediante
inmunohistoquímica y ME, pudiendo constatarse cambios a nivel de las células
FSH y LH, compatible con hiperfunción.
6.3.2
Influencia de la
fotoinhibición sobre las células lactotropas del Hamster Golden. Se utilizaron animales normales sometidos a
fotoperíodos cortos y prolongados. Los resultados mostraron cambios bioquímicos
que sugieren inhibición en la secreción de PRL luego de la deprivación de luz,
con recrudescencia espontánea al final del estudio.
7.
TRABAJOS DE
INVESTIGACION REALIZADOS O PUBLICADOS EN ESTE PERIODO.
7.1 PUBLICACIONES.
7.1.1 Cónsole, GM;
Jurado, SB; Oyhenart, E; Ferese, C; Pucciarelli, H; Gómez Dumm, CLA.
Morphometric and
ultrastructural analysis of different pituitary cell populations in
undernourished monkeys.
Braz. J. Med. Bil. Res.
34: 65-74, 2001.
Undernutrition elicited by
a low-protein diet determines a marked reduction of hypophyseal activity and
affects the function of the respective target organ. The objective of the
present investigation was to study the ultrastructural and quantitative
immunohistochemical changes of the different pituitary cell populations in
undernourished monkeys that had been previously shown to have significant
changes in craniofacial growth. Twenty Saimiri sciureus boliviensis
monkeys of both sexes were used. The animals were born in captivity and were
separated into two groups at one year of age, i.e. control and undernourished
animals. The monkeys were fed ad libitum a 20% (control group) and a 10%
(experimental group) protein diet fro two years. Pituitaries were processed for
light and electron microscopy. The former was immunolabeled with anti-GH, -PRL,
-LH, -FSH, -ACTH, and -TSH sera. Volume density and cell density were measured
using an image analyzer. Quantitative immunohistochemistry revealed a decrease
in these parameters with regard to somatotrophs, lactotrophs, gonadotrophs and
thyrotrophs from undernourished animals compared to control ones. In these
populations, the ultrastructural study showed changes suggesting compensatory
hyperfunction. On the contrary, no significant changes were found in the
morphometric partameters or the ultrastructure of the corticotroph population.
We conclude that in undernourished monkeys the somatotroph, lactotroph,
gonadotroph, and thyrotroph cell populations showed quantitative
immunohistochemical changes that can be correlated with ultrastructural
findings.
7.1.2 Cónsole, GM;
Oyhenart, Jurado, SB; Riccillo, FL; Pucciarelli, HM; Gómez Dumm, CLA. Effect of undernutrition on cranial components and
somatotroph-lactotroph pituitary populations in the squirrel monkey (Saimiri
Sciureus Boliviensis). Cells Tissues Organs 168 (4): 272-282, 2001.
The aim of the
present study was to investigate in monkeys the effects of undernutrition on
neurocranial and facial components, correlated with a histometric and ultrastructural
analysis of somatotroph (growth hormone, GH) and lactotroph (prolactin, PRL)
pituitary populations. Twenty Saimiri sciureus boliviensis (Cebidae) of
both sexes were employed. The monkeys were born in captivity and when they
reached 1 yera of age, they were separated into two groups: control and
undernourished animals. They were fed ad libitum a 20% and 10% protein diet,
respectively. The monkeys ere radiographed when they were 3 years old in order
to measure the length, width and height of the anterior, middle and posterior
components of the neurocranium, as well as those of the masticatory,
respiratory and optic components of the face. The volumetric and morphometric
indices were then calculated. After the sacrifice, pituitary glands were
processed for light and electron microscopy. The quantitative
immunohistochemistry revealed a decrease in the volume density and cell density
of both GH and PRL cells from malnourished animals when compared to control
ones. The ultrastructural study showed changes suggestive of cellular
hyperfunction for both types of cells in the former experimental group.
Undernutrition also affects the size of the cranial components, with males
being more affected than females; brain weight was, however, nonmodified by
stress, with the brain/body ratio difference being the same for both sexes. We
conclude that in momkeys, experimental undernutrition produces a decrease in
the pituitary GH and PRL cell populations, in some way related to changes in
the cranio-facial morphometric patterns.
7.1.3 Cónsole, GM;
Jurado, SB; Rulli, SB; Gómez Dumm, CLA; Calandra, RS.
Ultrastructural and
quantitative immunohistochemical changes induced by non-steroid antiandrogens
on pituitary gonadotroph populations of prepubertal male rats. Cells, Tissues
and Organs169 (1): 64-72, 2001.
Specific blokade of
the androgen receptor by the nonsteroid antiandrogens flutamide and Casdex has
proven to be a useful tool for studying androgens in vivo. The aim of the
presen study was to investigate the effect of antiandrogen administration at
the pituitary level by evaluating the ultrastructural changes in gonadotrophs,
in correlation with the quantitative immunohistochemical findings, and by
comparing these alterations with the effect of androgen deprivation by castration
either with or without subsequent androgen replacement. Male Sprague-Dawley
rats (23 days old) were grouped as follows: (1) controls, (2)
flutamide-injected (10 mg/rat/day), (3) Casodex-injected (10 mg/rat/day), (4)
castrated, and (5) castrated plus androgen-replaced (dihydrotestosterone
propionate; 40 mg/rat/day). Groups were sacrificed after 10 days of
maintenance under each condition. Pituitaries were processed for both light and
electron microscopy. Serial sections (4mm) were obtained at different levels and immunostained
by means of the primary murine monoclonal antibodies anti-FSH and anti-LH and a
peroxidase-mediated EnVision System (Dako). Volume density, cell density and
mean cell area were measured with an image analysis system (Imaging Technology,
Software Optimas 5.2). the mean cell area (p<0.001) and the volume density
(p<0.05) increased significantly in the flutamide- and Casodex-treated
groups as well as the castrated group of FSH and LH cells. On the other hand,
androgen replacement in the castrated rats, however, reduced in both parameters
related to control animals. The cell density of FSH-secreting cells was
increased (p<0.05) in the Casodex and flutamide treatment as well as
castrated group. The cell density of LH-secreting cells was augmented
(p<0.05) in the Casodex-treated group, while there was no increase in such
parameter with flutamide and castration. The ultrastructure of all groups
showed two types of gonadotrophs. Type I cells contained large (300-500 nm) and
small (150-200 nm) secretory granules, while type II cells were smaller, and
exhibited only small granules (100-200 nm). Flutamide-treated, Casodex-treated
and castrated groups presented a decreased number of secretory granules with
some exocytotic profiles, well-developed rough endoplasmic reticulum and an
expanded Golgi complex of both types of cells. The gonadotrophs from the
castrated group exhibited numerous mitochondria with electron-dense ring-shaped
laminar figures, while in the castrated plus androgen-replaced rats only a few
mitochondria had similar changes to those observed in castrated animals, as a
possible residual alteration. Finally, the gonadotrophs from flutamide-treated
rats showed mitochondrial alterations with clears areas and isolated
electron-dense laminar figures. In summary, we conclude that lack of androgen
reaction through the effects of nonsteroid antiandrogens and castration on
prepuberal rats produced a hypertrophia-hyperplasia of the FSH cells, and
hypertrophia of LH-secreting cells, with marked alterations at the
ultrastructural level suggestive of a hyperstimulation stage.
7.1.4 Del Zotto, H; Gómez
Dumm, CLA; Drago,S; Fortino, A; Luna, GC; Gagliardino JJ. Mecanismo de
producción del aumento de la masa de células B inducido por la administración
crónica de sacarosa a ratas normales. Revista de la Soc. Arg. De Diabetes. 35:
103-111, 2001.
El objetivo del siguiente trabajo fue clarificar
los mecanismos mediante los cuales una dieta rica en sacarosa produce, en el
páncreas de la rata, un aumento de la masa celular B. Se utilizaron ratas
Wistar normales, alimentadas durante 30 semanas con una dieta rica en sacarosa
(DRS; 63%) o bien con una dieta similar en la que la sacarosa se reemplazó por
la misma proporción de almidón (DC). Se estudió el peso corporal, los niveles
séricos de glucosa y triacilglicerol, el tejido endocrino, la masa celular B,
el grado de replicación de las células B (antígeno de proliferación nuclear
celular, PCNA), la neogénesis insular (inmunomarcación de citoqueratina, CK) y
la apoptosis de células B (yoduro de propidio). El peso corporal de las rats
DRS fue significativamente mayor (p<0,05) que el registrado en el grupo DC
(556,0±8,3
vs 470,0±13,1).
Tanto los niveles séricos de glucosa como los de triacilglicerol (mmol/L)
fueron significativamente mayores (0,05<) en las ratas DRS que en las DC:
glucemia 8,11±0,14
vs 6,62±0,17;
triacilglicerol 1,57±0,18
vs 0,47±0,04).
El número de islotes pancreáticos por unidad de área aumentó significativamente
(p<0,05) en las ratas DRS (3,29±0,1
vs 2,01±0,2).
Además, se detectó un incremento significativo (2,6 veces) en la masa de tejido
endocrino de los animales DRS, principalmente debido a un aumento en la masa
celular B (p=0,0025). El porcentaje de células B insulares en replicación (PCNA
positivas) aumentó 6,8 veces en las ratas DRS (p<0,03). El número de células
apoptóticas del páncreas endocrino disminuyó significativamente en el grupo DRS
(3 veces, p=0,03). No hubo diferencias significativas en el área positiva para
CK entre los DRS y DC. El aumento de la masa celular B inducido por la DRS se
correspondió con un aumento en la replicación de las células B, junto con una
disminución en la proporción de dichas células en apoptosis. No hubo evidencias
de neogénesis en los islotes. Dichos cambios pancreáticos no pudieron mantener
la glucemia de estos animales en valores semejantes a los obtenidos en las ratas
DC. Estos resultados muestran que en este modelo de manipulación alimentaria,
aunque el aumento de replicación de las células B y la disminución de la
apoptosis jugarían un rol importante, la neogénesis insular constituiría el
mecanismo compensador decisivo en la adaptación a la mayor demanda de insulina.
7.1.5 Goya, RG; Cónsole, GM; Sosa, YE; Gómez Dumm,
CLA; Dardenne, M. Altered functional responses with preserved morphology of
gonadotrophic cells in congenitally athymic mice. Brain, Behavior and Immunity
15: 85-92, 2001.
Neonatal thymectomy or
congenital absence of the thymus induces severe reproductive deficiencies in
female mice, in which are associated with reduced levels of circulating and
pituitary gonadotropins. In contrast, the reproductive function is well
preserved in nude males. It was therefore of interest to asses gonadotrophic
cell morphology and function in congenitally athymic male mice. circulating
gonadotropins were measured under basal and stressful conditions, taking as a
reference their haired counterparts. Adult normal (+/+), heterozygous nude (nul
+), and homozygous (un/un) CD-1 mice were subjected to 1-h immobilization
stress. Serum level of luteinizing hormone (LH) and follicle-stimulating
hormone (FSH) were assessed by RIA at 0,30, and 60 min poststress. Athymic
animals showed significantly lower basal levels of serum LH and FSH cell
populations revealed a normal morphology and cell number in the athymic animals
compared to their normal littermates. Immobilization stress induced a
significant reduction in gonadotrophin levels, particularly LH, in normal mice
but had only a weak affect in athymic animals. It is concluded that congenital
athymia in the adult male mouse is associated with decreased basal levels of
serum LH and FSH, in the presence of a normal gonadotroph number and
morphology. The anomalous responses of mice to stress do not appear to be due
to primary hypopituitarism but, rather, to an altered modulation of pituitary
hormone secretion.
7.1.6 Cónsole, GM, Jurado SB, Petruccelli M, Carino M, Calandra
RS, Gómez Dumm CLA. Influence of photoinhibition on the morphology and function of pituitary
lactotropes in male golden hamster. Neuroendocrinology 75:
316-325, 2002.
Inhibition of prolactin
(PRL) secretion has been previously shown in pituitaries from male and female
hamsters exposed to short photoperiods. The purpose of the present study was to
analyze the possible quantitative immunohistochemical and ultrastructural
changes of PRL cells in male golden hamsters undegoing regression and
spontaneous recrudescence, correlating the morphological findings with
circulating PRL levels. Thus, adult male golden hamsters were exposed for 8,
16, 22 and 28 weeks to either short photoperiods (SP: 6 h light, 18 h darkness)
or long photoperiods (LP: 14 h light, 10 h darkness). Pituitaries were
processed for both light and electron microscopy, and serum levels of PRL were
assessed by radioimmunoassay (RIA). Volume density (VD= cell area/reference
area) and cell density (CD= number of cells/reference area) of lactotropes were
measured with an image analysis system (Imaging technology, Software Optimas
5.2). one hundred lactotropes were recorded for measuring several
ultrastructural parameters. Whn analyzing the lactotrope cell population from
animals submitted to SP, the VD and CD were found to be significantly
(p<0,05) diminished with respect to those of the groups submitted to LP ar
weeks 8, 16 and 22. However, at week 28 a spontaneous recrudescence appeared.
The lactotropes from animals submitted to LP for 8, 16, 22 and 28 weeks
exhibited numerous large electrondense secretory granules. The rough
endoplasmic reticulum (RER) presented some flat cisternae and numerous free
ribosomes. Animals submitted to SP for 8 weeks showed a number of medium and
large secretory granules, and the RER exhibited mainly numerous free ribosomes.
In those animals submitted to SP for 16 and 22 weeks, lactotropes were found
smaller and decreased in number. The Golgi complex exhibited some immature
granules and dilated cisternae, while the RER did not present differences with
respect to the 8-week SP group. The hamsters submitted to SP for 28 weeks
presented medium and large secretory granules, and the RER exhibited dilated
irregular cisternae. The ultrastructural morophometric parameters showed a
decreased (p<0,05) in the number of secretory granules and exocytotic
profiles, as well as a diminution (p<0,05) in the areas of Golgi complex,
RER, secretory granules, and individual mean area of secretory granule during
the 16 and 22 weeks of SP. Serum PRL levels were severely reduced under SP.
This decrease was greater at 16 weeks than at 8 weeks of exposure under SP, PRL
levels started their recovery. Thus, at the end of the experiment, the PRL
values returned to near those of LP group. In summary, we found quantitative
immunohistochemical and ultrastructural, as well as biochemical changes that
suggest an inhibition of synthesis, storage and release of PRL in male golden
hamsters submitted to SP, with a spontaneous recrudescence appearing at the end
of the study.
7.1.7 Del Zotto H, Gómez
Dumm CL, Drago S, Fortino A, Luna GC and Gagliardino JJ. Mechanisms involved in
the B-cell mass increase induced by chronic sucrose feeding to normal rats. J
Endocrinol 174: 225-231, 2002.
The aim of the present
study was to clarify the mechanisms by which a sucrose-rich diet (SRD) produces
an increase in the pancretic b-cell
mass in the rat. Normal Wistar rats were fed for 30 weeks either an SRD (SRD
rats; 63% wt/wt), or the same diet but with starch instead of sucrose in the
same proportion (CD rats). We studied body weight, serum glucose and
triacylglycerol levels, endocrine tissue and b-cell
mass, b-cell
replication rate (proliferation cell nuclera antigen; PCNA), islet neogenesis
(cytokeratin immunostaining) and b-cell
apoptosis (propidium iodide). Body weight (g) recorded in the SRD rats was
significantly (p<0.05) larger than that of the CD group (556.0±8.3 vs 470.0±13.1). Both serum
glucose and tricylglycerol levels (mmol/l) were also significantly higher
(p<0.05) in SRD than in CD rats
(serum glucose, 8.11±0.14
vs 6.62±0.17;
triacylglycerol 1.57±0.18
vs 0.47±0.04).
the number of pancreatic islets per unit area increased significantly
(p<0.05) in SRD rats (3.29 ±0.1
vs 2.01±0.2).
A significant increment (2.6 times) in the mass of endocrine tissue was
detected in SRD animals, mainly due to an increase in the b-cell mass
(p=0.0025). the islet cell replication rate, measured as the percentage of PCNA-labelled
b cells increased
6.8 times in SRD rats (p<0.03). The number of apoptotic cells in the
endocrine pancreas decreased significantly (three times) in the SRD animals
(p=0.03). The cytokeratin-positive area did not show significant differences
between CD and SRD rats. The increase of
b-cell
mass induced by SRD was accomplished by an enhanced replication of b cells together
with a decrease in the rate of b-cell
apoptosis, without any evident participation of islet neogenesis. This
pancreatic reaction was unable to maintain serum glucose levels of these rats
at the level measured in CD animals.
7.5 COMUNICACIONES
Camillión de Hurtado M, Ennis IL, Escudero EM,
Camihort G, Cónsole G, Gómez Dumm CL, Cingolani HE. Na+/H+
inhibition attenuates isoproterenol-induced cardiomyocte hypertrophy.
Georg-August-Universität Göttingen, 2nd International Göttingen Heart Failure Conference. La Plata, Argentina,
May 2002.
Luna G, Camihort G, Jurado S, Gómez Dumm C, Spinedi
E, Cónsole G. Morfología del tejido adiposo (parietal y visceral) y su relación
con la leptina en un modelo de denervación hipotalámica. XLVII Reunión de la
Sociedad Argentina de Investigación Clínica, Mar del Plata, 2002.
MEDICINA 62: 468, 2002
11. DIRECCION DE BECARIOS Y/O INVESTIGADORES.
Lic. Fernando Riccillo,
Beca de Perfeccionamiento. Comisión de Investigaciones Científicas de Buenos
Aires (CIC, BA). Tema: “Efecto del envejecimiento sobre el páncreas
endocrino de la rata.”(1997-1998; 1998-2000; 2001-2002).
12. DIRECCION DE TESIS.
Director de la Tesis de
la Médica Veterinaria Susana Jurado, para optar al Doctorado en Medicina
Veterinaria, Facultad de Ciencias Veterinarias, UNLP. Tema:
"Impacto del envejecimiento sobre las poblaciones celulares
adenohipofisarias de la rata. Estudio inmunocitoquímico y ultraestructural".
Finalizada. Falta fecha de defensa.
13. PARTICIPACION EN REUNIONES CIENTIFICAS.
14. CURSOS DE PERFECCIONAMIENTO, VIAJES DE ESTUDIO, ETC.
15. SUBSIDIOS RECIBIDOS EN EL PERIODO.
Proyectos 2001
DIABETES MELLITUS: ASPECTOS
BÁSICOS, CLÍNICOS Y EPIDEMIOLÓGICOS III - Código 11/M091
Monto: $ 1836.62
PICT 05-04118 - Desarrollo
de las poblaciones celulares insulares y de la secreción de insulina: rol de
moduladores hormonales y señales intracelulares en condiciones normales y de
insulinorresistencia inducida por sacarosa.
Monto: $ 17.500
Proyectos 2002
PICT 05-04118 - Desarrollo
de las poblaciones celulares insulares y de la secreción de insulina: rol de
moduladores hormonales y señales intracelulares en condiciones normales y de
insulinorresistencia inducida por sacarosa.
Monto: $......
16. DISTINCIONES O PREMIOS OBTENIDOS EN EL PERIODO.
17. ACTUACION EN ORGANISMOS DE PLANEAMIENTO, PROMOCION O EJECUCION
CIENTIFICA Y TECNOLÓGICA.
18. TAREAS DOCENTES DESARROLLADAS EN EL PERIODO.
Tareas correspondientes al cargo de profesor
Titular con Dedicación Exclusiva, rentado por concurso, de la Cátedra de
Histología y Embriología "B", Fac. de Cs. Médicas, UNLP. (Hasta el 31
de marzo de 2001).
Profesor Extraordinario Consulto, según
decisión del Consejo Académico de la Fac. de Cs. Médicas, UNLP.
19. OTROS ELEMENTOS DE JUICIO NO CONTEMPLADOS EN LOS TITULOS
ANTERIORES.
20. TITULO Y PLAN DE TRABAJO A REALIZAR EN EL PROXIMO PERIODO.
20.1 Regulación de la diferenciación y
crecimiento de poblaciones celulares del islote pancreático (CENEXA). Nuestro grupo de
investigación posee amplia experiencia en el estudio de la regulación de la
masa celular del páncreas endocrino, especialmente de la población beta, bajo
diferentes condiciones experimentales (fetos y adultos normales, diabetes,
dieta rica en sacarosa, etc.). Últimamente se ha incluídos la detección de la
proteína asociada a la neogénesis insular (INGAP). Los objetivos del nuevo
proyecyo comprnden el estudio de la dinámica de la masa celular endocrina
(replicación, neogénesis, apoptosis) mediante morfometría e inmunohistoquímica,
incluidas las células INGAP positivas, en ratas (fetos y adultas) normales, y
con insulinoresistencia inducida por dieta rica en sacarosa.
20.2 Estudio morfológico de las
poblaciones adenohipofisarias en un modelo de ratas con obesidad experimental.
Se estudiarán ratas tratadas con glutamato monosódico (MSG) y bajo dieta normal
e hiperlipídica. se aplicarán técnicas inmunohistoquímicas cualitativas y ME
para analizar los cambios a nivel de la adenohipófisis. Además, se estudiará el
tejido adiposos, responsable de la secreción de leptina circulante. Los
resultados se correlacionarán con estudios bioquímicos (Unidad
Neuroendocrinología, IMBICE).