Coelomic cells show apoptosis via Fas/FasL system: a comparative study between healthy human pregnancies and missed miscarriages.
BACKGROUND
The Fas/Fas ligand (FasL) system represents one of the main apoptotic pathways controlling placental apoptosis throughout gestation. In the current study, we have examined the Fas/FasL protein expression and the apoptotic incidents of coelomic cells, amniotic cells and trophoblastic tissue in first trimester human pregnancies and missed miscarriages (MM).


METHODS
Protein expression was determined by immunofluoresence, western blotting analysis, immunohistochemistry and indirectly by RT-PCR, whereas apoptotic cell death was assessed by in situ DNA fragmentation analysis.


RESULTS
Coelomic cells express Fas/FasL proteins, can undergo apoptosis and were the only cells in which apoptosis, Fas protein expression and FasL protein expression were accordingly increased along with gestational age (P = 0.001, P = 0.008; P = 0.012, respectively). In contrast, amniotic cells and trophoblast showed a consistency in the expression levels of Fas/FasL proteins in healthy pregnancies. MM were accompanied by increased Fas/FasL protein expression in all examined samples (P < 0.001). The increase of Fas/FasL protein expression was accompanied by proportional increase of apoptotic incidents among the coelomic cell population (P = 0.023, P = 0.009, respectively), whereas amniotic cells and trophoblast appeared to be resistant to Fas-induced apoptosis. The lowest expression of Fas/FasL proteins and the minimum occurrence of apoptotic incidents were detected in the trophoblast.


CONCLUSIONS
These data suggest that there is a different regulation and function of the Fas/FasL system in early human pregnancies. Aberration of the Fas-mediated apoptosis may represent one of the execution-step necessary for pregnancy loss in MM cases.
Kaponis
A
A
Department of Obstetrics and Gynecology, Ioannina University School of Medicine, Ioannina, Greece. kaponisapostolos@hotmail.com
Skyrlas
A
A
Zagorianakou
N
N
Georgiou
I
I
Passa
V
V
Paraskevaidis
E
E
Makrydimas
G
G
D000030:Abortion, Missed / Q000503:physiopathology*; D000328:Adult; D000653:Amniotic Fluid / Q000166:cytology; D017209:Apoptosis / Q000502:physiology*; D053222:Fas Ligand Protein / Q000502:physiology*; D005260:Female; D006801:Humans; D020287:In Situ Nick-End Labeling; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D014327:Trophoblasts / Q000166:cytology / Q000502:physiology; D019014:fas Receptor / Q000502:physiology*
D053222:Fas Ligand Protein; D012333:RNA, Messenger; D019014:fas Receptor