The nucleolar channel system reliably marks the midluteal endometrium regardless of fertility status: a fresh look at an old organelle.
OBJECTIVE
To determine whether nucleolar channel systems (NCSs) in the midluteal endometrium are associated with overall fertility status and/or with unexplained infertility.


METHODS
Retrospective and prospective clinical studies.


METHODS
Repository of stored specimens from prior multicenter study and private infertility center.


METHODS
Retrospective study that included 97 women (49 fertile couples, 48 infertile couples) who had been randomized for endometrial biopsy during the midluteal or late luteal phase. The prospective study included 78 women with a variety of infertility diagnoses.


METHODS
Endometrial biopsies were obtained and assessed for the presence of NCSs by indirect immunofluorescence.


METHODS
The presence of NCS was graded semiquantitatively and dichotomized as normal versus low or absent.


RESULTS
Normal presence of NCS was significantly associated with the midluteal phase compared with the late luteal phase (80% vs. 29%). However, there was no association between presence of NCS and fertility status or between presence of NCS and unexplained infertility.


CONCLUSIONS
Midluteal phase endometrium consistently forms NCSs regardless of fertility status, including unexplained infertility. This indicates a possible role for the NCS in initiating the window of endometrial receptivity. However, the consistent presence of NCSs across several different types of infertility challenges the likelihood that inadequate secretory transformation is a cause of infertility.
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Eli A
EA
Rybak
Michael J
MJ
Szmyga
Gregory
G
Zapantis
Mary
M
Rausch
Victor E
VE
Beshay
Alex J
AJ
Polotsky
Christos
C
Coutifaris
Bruce R
BR
Carr
Nanette
N
Santoro
U Thomas
UT
Meier
D000328:Adult; D002466:Cell Nucleolus / Q000502:physiology*; D004717:Endometrium / Q000502:physiology*; D005260:Female; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis* / Q000503:physiopathology*; D008183:Luteal Phase / Q000502:physiology*; D011446:Prospective Studies; D012189:Retrospective Studies