The Placenta of the Rat - ESTP Home Page · 2014-09-12 · Histopathology of the labyrinth...
Transcript of The Placenta of the Rat - ESTP Home Page · 2014-09-12 · Histopathology of the labyrinth...
The Placenta of the Rat Histology and Pathology
Cutting Edge Pathology 2014
Second Joint European Congress of the ESTP, ESVP and ECVP
Dr. Maria Cecilia Rey Moreno
Comparative morphology of the placenta
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Modified from: Chavatte-Palmer & Guillomot (2007)
Comparative Implantation and Placentation;
Bernirschke, Kaufmann & Baergen (2006)
Pathology of the human placenta
Diffuse
Horse, pig, whale
Zonary Cotyledonary Discoidal
Ruminants Carnivores
Human
Monkeys (bidiscoidal)
Rodents
General characteristics shared by all species
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Transient organ: supplies embyonal/fetal nutrition, growth and protection
Vascular organ: close proximity of maternal and fetal vascular systems with large transfer
contact surface between each other
Interhemal membrane (placental barrier): separates maternal and fetal blood separated
in their own compartments; site of transfer
General functions: O2/CO2 transfer, water balance, synthesis and secretion of steroid
hormones, paracrine and growth factors, metabolic and immunologic functions (immune
tolerance)
Origin: trophectoderm of the blastocyst
Trophoblast cell: parenchymal cells of the placenta; different subtypes with different
locations and functions
Cutting Edge Pathology 2014
Gestational period and life-span of the rat
placenta
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 / 22
Fertilization Implantation Birth
days
Placenta
GD21/22
Yolk sac
Decidua
Placenta
Placentation
Blastocyst
Gestational
day (GD) 5/6
Trophectoderm→
Histology of the placental development
in the rat
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GD8 GD10 GD12 Non-pregnant uterus
GD14 GD16 GD18 GD21
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GD8/9: Decidualization and anastomosis
of maternal vasculature
Mesometrial side
Mesometrial
triangle
Uterine
lumen
Antimesometrial side
Decidua
Implantation
*
*
Decidualization (*): proliferation and
differentiation of stromal cells
Site of developing placenta:
ectoplacental cone (EPC)
Embryo
Allantois
Giant
trophoblast
cell
Yolk sac
Anastomosis of maternal vessels
around the embryo
GD10: Yolk sac and placental
cone differentiation
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Ectoplacental
Cone
Yolk sac
membrane
Decidua
(D)
Chorion
Uterus
lumen
2
3
D
D Mesometrial
triangle
D
GD12: Chorio-allantoic placentation:
interhemal membrane formation
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Actin smooth muscle IHC:
fetal blood vessel walls
Morphogenesis of
fetal vessels
and maternal sinuses
A
C
A: Allantois
C: Chorion
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First half of gestation:
Uterine natural killer cells (uNK)
Mesometrial triangle:
sheaths of uNK (or granulated mesometrial
cells) around spiral arteries
GD10/12: Remodeling of spiral arteries
GD10
Second half of gestation:
trophoblast cell invasion
Decidua:
Intravascular and interstitial trophoblast cell
invasion; apoptosis of uNK
GD12
GD10/18: Remodeling of spiral arteries
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β-Actin:
smooth muscle
Cytokeratin
Pan-26:
trophoblast cell
GD18 GD10
GD18 GD10
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Vimentin: fetal vessels
GD14/16: Maturation of materno-fetal
interhemal membrane
HE
Alignment of
fetal vessels
GD14
GD14
GD16
GD16
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GD18: Mature and fully functional:
differentiation completed
Fetal demands
Efficiency
Placental size unchanged
Branching + dilation of fetal capillaries
Thickness of interhemal membrane
Remodeling:
Rat placenta at GD 21
General characteristics
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Shape
Interhemal membrane
Fetal blood
(capillary)
Maternal blood
(sinus)
I
II
III
I: Cytotrophoblast cells
II + III: Syncytiotrophoblast
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Discoidal
Hemotrichorial
Interdigitation
Labyrinthine
Rat placenta at GD 21
General structure
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Kaufmann P., 2005
http.//placentation.u
csd.edu/rat.htm
L
T
D
UW
UC
UM
Fetal side
Maternal side
SP
MT
Labyrinth (L)
Trophospongium (T)
Decidua (D)
Uteromaternal channel (UM)
Mesometrial triangle (MT)
Spiral arteries (SP)
Uterine wall (UW)
Umbilical cord (UC)
Yolk sac (YS)
Amniotic membrane (AM)
Cutting Edge Pathology 2014
YS
AM
Histology of the normal labyrinth at GD21
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Maternal sinus (M)
Fetal capillary (F)
Cytotrophoblast (C)
Syncytiotrophoblast (S)
M
F
S
C
Cutting Edge Pathology 2014
Interhemal membrane
Histology of the normal trophospongium
at GD21
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(L)
Sp
Gly
(UM)
Cutting Edge Pathology 2014
Spongiotrophoblast cells (Sp)
Glycogen trophoblast cells (Gly)
Giant trophoblast cells
Uteromaternal channel (UM), lined by parietal trophoblast cells (Pa)
Pa
Histology of the normal decidua at GD21
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Spiral arteries (S)
Glycogen trophoblast cells (Gly)
Decidual cells (D)
Uterine natural killer cells (uNK) (or granulated
mesometrial cells)
uNK
Gly
D
Cutting Edge Pathology 2014
S
Research by BASF SE
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Birth Defects Research Part B (2013)
98 3 208-221, 230-246, 247-259
Epoxiconazole (EPX)
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Inhibits CYP51 (lanosterol 14α-
demethylase), a key fungal enzyme
aromatase estradiol testosterone
CYP 19
CYP 51
ergosterol lanosterol
Epoxiconazole
Antifungal agrochemical: azole
class
Proven effectiveness against
fungi which resist other classes
Inhibits CYP19 (aromatase) in
mammals
Cutting Edge Pathology 2014
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Mechanistic studies with Epoxiconazole
in rats
Two Modified Prenatal Developmental Toxicity Studies (OECD 414) in rats
Hormone measurements
Hematology and clinical chemistry
Pathology (organ weights, histopathology)
Study 2 Study 1
Administration of Epoxiconazole (EPX)
Maternal adverse effects (↓ weight,
↓maternal serum estrogen, anemia, liver
parameters altered, etc.)
↑ late fetal resorptions
↑ placental size
Histopathological changes in placenta
Pathology:
Material + Methods
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Uterus extracted in toto
Uterus opening at the antimesometrial
side
Placentas remained attached to the
uterus
Fixation: 10% neutral buffered formalin
(24 - 48 h); transferred to 70% ethanol
Trimming: transverse cut at the center
of the disc (mid-sagittal section)
Routine HE histotechnical processing
Mean/median grading of
degeneration/litter (statistical analysis)
Macroscopic findings
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Control
Treated (50 mg/kg bw/d
EPX)
Late resorption Placenta with
live fetus
Cutting Edge Pathology 2014
EPX : Epoxiconazole
Histopathology of the labyrinth
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Control, GD 21; HE, 2.5x
Normal architecture of the labyrinth
Treated, GD 21, HE, 2.5x
Degeneration, labyrinth, grade 4
Cystic dilation of vascular spaces filled with blood
and/or fibrin replace the normal structure of the
labyrinth (50 - 70%).
Rey Moreno MC et al. (2013)
Birth Def Res (Part B) 98:208-211
Histopathology of the labyrinth
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Control, GD 21, HE, 20x
Normal architecture of the labyrinth
Treated, GD 21, HE, 20x
Disruption of interhemal membrane
Filiform and irregular remnants of interhemal
membranes; degeneration of trophoblast cells.
Rey Moreno MC et al. (2013). Birth Def Res (Part B) 98:208-211
Rey Moreno MC et al. (2013)
Birth Def Res (Part B) 98:208-211
Rey Moreno MC et al. (2013)
Birth Def Res (Part B) 98:208-211
Histopathology of the trophospongium
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Control, GD 21, HE, 2.5x
Normal architecture of the
trophospongium
Treated, GD 21, HE, 2.5x
Degeneration, trophospongium, grade 2
Increased thickness of trophospongium (2-fold),
disorganized aspect, increased eosinophilia, dilation
of maternal venous spaces
L
T
T
L
Rey Moreno MC et al. (2013)
Birth Def Res (Part B) 98:208-211
Rey Moreno MC et al. (2013)
Birth Def Res (Part B) 98:208-211
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Degeneration in a placenta with a live
fetus
**
*
Cutting Edge Pathology 2014
Labyrinth: Treated, GD21, HE, 4x
Degeneration, labyrinth, grade 2
Cystic dilations **
Mineralization of fetal vessels *
Trophospongium: Treated, GD21, HE, 4x
Degeneration, trophospongium, grade 3
Disorganization of architecture
Necrosis (↑)
Degeneration in a placenta with a late
resorption
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m
*
*
*
Cutting Edge Pathology 2014
Labyrinth: Treated, GD21, HE, 4x
Degeneration, grade 5
Cystic dilations * (> 70%)
Mineralization of fetal vessels (↑)
Trophospongium: Treated, GD21, HE, 4x
Degeneration, grade 4
Extensive necrosis (*) and fibrinoid deposit
* *
*
UA
D
Severity of degeneration was dose-dependent
and associated with the fetal outcome
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(Live Fetus)
(Late Resorption) (Late Resorption)
(Live Fetus) = control
= low dose EPX
(23 mg/kg bw/day)
= high dose EPX
(50 mg/kg bw/day)
Rey Moreno MC et al. (2013). Birth Def Res (Part B) 98:208-211
Severity of degeneration was dose-dependent
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(Live Fetus)
(Late Resorption) (Late Resorption)
(Live Fetus) = control
= low dose EPX
(23 mg/kg bw/day)
= high dose EPX
(50 mg/kg bw/day)
Mechanistic studies with Epoxiconazole
in Rats
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Two Modified Prenatal Developmental Toxicity Studies (OECD 414) in Rats
Hormone measurements
Hematology and clinical chemistry
Pathology (organ weights, histopathology)
Study 1
Administration of EPX
↓ rat maternal serum estrogen
↑ late fetal resorptions
↑ placental size
Histopathological changes in placenta
(labyrinth and trophospongium)
Study 2
Administration of EPX + estradiol
↓ rat maternal serum estrogen
↓ late fetal resorptions
↓ placental size
↓ severity of histopathological
changes in placenta (labyrinth and
trophospongium)
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(Live Fetus) (Live Fetus)
Severity of degeneration decreased with
increasing estrogen supplementation
= control
= 50mg/kg bw/d EPX
= 50mg/kg bw/d EPX
+ 0.5 µg/d estrogen
= 50mg/kg bw/d EPX
+ 1.0 µg/d estrogen
(Late Resorption) (Late Resorption)
Rey Moreno MC et al. (2013). Birth Def Res (Part B) 98:208-211
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(Live Fetus) (Live Fetus)
(Late Resorption) (Late Resorption)
Severity of degeneration decreased with
increasing estrogen supplementation
= control
= high dose EPX
= high dose EPX +
0.5 µg/d estrogen
= high dose EPX +
1.0 µg/d estrogen
Rey Moreno MC et al. (2013). Birth Def Res (Part B) 98:208-211
Conclusions
Maternal estrogen depletion caused by EPX aromatase inhibition was
associated with rat placental degeneration
Placental degeneration appeared to be critical for the viability of fetus
and was associated with late fetal resorptions
Supplementation of estrogen ameliorated placental degeneration
leading to a lower number of late resorptions
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Guinea pig exposed to EPX (prenatal and pre-postnatal toxicity studies)
revealed: no histopathological findings in placenta and no late resorptions
Conclusions
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Regulation of pregnancy Rat Guinea pig Human
Aromatase expression maternal ovaries placenta placenta
Source: Estrogen maternal ovaries placenta placenta
Source: Progesterone corpus luteum corpus luteum/placenta corpus luteum/placenta
Guinea pigs and humans have a similar placental hormonal synthesis
Rat Human Guinea Pig
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Lab technicians and colleagues:
Pathology & Reprotox
Vinzenz Stahl
Thank you !