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1. Greetings from Chennai, India
ASPIRE - 2008
II World Congress
Singapore
April 11-13,2008

2. SMOOTH ENDOPLASMIC RETICULUM
CLUSTERS AND ICSI OUTCOME
V.Thomas
Chief Embryologist
Dr T R Varma
Medical Director
Institute of Reproductive Medicine
Madras Medical Mission
Chennai, India

3. Introduction
• Veek (1988) –Good quality MII oocytes
should show clear and colourless
cytoplasm with moderate granulation and
no inclusions,
a small PVS, and a clear ZP.
• However, more than half of all human
oocytes collected show at least one
morphological abnormality.

4. MINOR DYSMORPHISMS
• Incorporations or refractile bodies
– unlikely to have any impact on
fertilization
rate and embryo quality in ICSI patients
• Whereas
Vacuoles or aggregations of smooth
endoplasmic reticulum (SER) will
impair developmental capacity of
human oocytes.

5. ROLE OF OOCYTE MORPHOLOGY AND
ICSI OUTCOME
• Alikani et al 1995,desutter 1996 – oocyte
morphology does not affect fertilization and
embryoscores.
• Serhal et al 1997,Lourtradis et al 1999 –
oocyte morphology does have impact on
implatation and clinical pregnancy rates.
• Balaban et al 1998 – no influence of oocyte
morphology on clinical pregnancy rates.

6. SERC
• What is SERC?
• How common is it?- ( 9-13%)
• Why does it happen ?– not known, possibly
duration of gonadotrophins (Otsuki et al 2004)
Evidence of its effect on fertilization, cleavage and
pregnancy rates ?
• 2004 Otsuki et al – The presence of SERC is
associated with normal fertilization and cleavage
but lower clinical pregnancy rates.

7. SERC – Literature Review
• There are very few studies published in literature
on SERC and ICSI outcome.
• Otsuki et al 2004 – The presence of SERC is
associated with normal fertilization and cleavage
but lower clinical pregnancy rates.
• Ebner et al 2008 – found lower fertilization and
cleavage rates and lower pregnancy rates in
women with SERC positive oocytes.

8. The role of Smooth endoplasmic
reticulum
• It increases surface area for the action or storage of
key enzymes (eg: Glucose 6 phoaphatase )
• It serves as a store of calcium and acts as a detoxifier
• In the oocyte it has a key role in regulating calcium
influx during fertilization.

9. ER Cluster Formation Is
Related to Cell Cycle
• The development of the ER clusters on the vegetal
side is observed during maturation. Small clusters
first appear at time of germinal vesicle breakdown.
• The clusters disappear and then reappear by the
time of second meiotic metaphase arrest as large
clusters.
• The timing suggests that small clusters appear
during meiosis I metaphase and disappear during
first polar body formation, perhaps at anaphase,
and then large clusters appear during meiosis II
metaphase. (De Sutter et al., 1996; Balaban et
al., 1998; Ebner et al.,2001).

10. • Fundamental changes occur in Ca2+
physiology during ovum maturation
• Central physiological event at fertilization is
an intracellular Ca2+ wave that begins at the
sperm entry site (Stricker, 1999)
• Ca2+ is released from internal membrane
stores, THE ENDOPLASMIC
RETICULUM (ER)
• Changes in the structure & redistribution
of the ER

11. Smooth Endoplasmic Reticulum
clusters (SERC)
• The Ca2+ source in SERC is altered
leading to abnormal oocyte maturation
and Ca2+ signalling for embryonic
development.
• Mechanisms responsible for SER
clusters are unknown.
• SERCs in human oocytes require future
studies at the molecular level.

12. Oocyte – Cytoplasmic abnormalities
Oocyte with normal cytoplasm Oocyte with granular cytoplasm Oocyte with big vacuole
Oocyte with Refractile body Oocyte with small vacuole Oocyte with SERC

13. M II – Oocyte with SER Clusters M II – Oocyte with vacuole
Vacuoles are membrane bound
Cytoplasmic inclusions filled with
Fluid-derived from SER or golgi
Apparatus.
High E2 concentration on the day
Of HCG may be one of the reason
for SERC formation

14. SERC & ICSI

15. t-SER
v-SER
Smooth
endoplasmic
reticulum
Courtesy of
Prof. Azumaya
Plenty of tubular and vesicular smooth ER showed active synthesis of proteins in ooplasma.

16. SERC
Smooth
Endoplasmic
Reticulum
clusters
Courtesy of
Dr.Otsuki

17. Our study
• Type of Study: Retrospective analysis
Materials and Methods:
• ICSI outcome of 510 patients
• 53 had oocytes with SERC
• We looked at proportion of oocytes with SERC
• Fertilization , cleavage, embryo grade and clinical
pregnancy rates.
• These were compared to patients without SERC in
their oocytes.

18. Results
• Incidence of SERC in our study – 13%
SERC (+) SERC (-) P-value
Fertilization : 86% 84% NS
Cleavage 94% 96% NS
Embryo grade
(A+B)
65% 68% NS
Pregnancy Rate 32% 67% P<0.05
Ongoing Pregnancy 9.3% 55% P<0.05
Biochemical 22.7% 6.8% P<0.05
Missed Abortion 1.9% 1.7% NS

19. 0
10
20
30
40
50
60
70
SERC + SERC -
PREGNANCY
ONGOING
BIOCHEM
MISSED
32%
22%
9%
2%
67%
55%
7%
1.7%
SERC & ICSI OUTCOME

20. Conclusion
• SERC adversely affects clinical pregnancy rates
following ICSI.
• Fertilization , cleavage and embryo grade are not
affected.
• Even small proportionate of oocytes with SERC in
a cohort may have an overall negative prognosis.
• This is probably because smaller SERCs cannot be
seen at standard magnifications (40X) which we
use for ICSI.
• High estradiol levels could be one of the cause of
SERC formation.
• Our results are similar to those of otsuki et al
(2004).

21. Acknowledgment
Medical Team
Thangam Varma PhD
Sathya MD
Shalu Gupta MD
Betty MD
Research Team
Stephen MS
Hema MS