Transcript Premature Ovarian Aging and Infertility

Premature Ovarian Aging and
Infertility
Definitions
• Infertility – Inability to conceive after one year of
unprotected coitus
• Assisted reproductive technologies – Infertility
procedures involving the fertilization of gametes outside
the human body
– In vitro fertilization (IVF)
– Gamete intrafallopian transfer (GIFT)
– Zygote intrafallopian transfer (ZIFT)
– Intracytoplasmic sperm injection (ICSI)
• Fecundity – The per cycle probability of conception
resulting in a live birth
Infertility Diagnoses in Patients
Utilizing ART
Centers for Disease Control and Prevention Assisted Reproductive Technology Success Rates, 2001.
Infertility
• 1995 National Survey of Family Growth
Statistics
– 10.2% of reproductive age women (6 million) had
impaired fecundity
– 15.4% of reproductive age women (9 million) had
ever utilized some type of infertility service
– 1.2 million visits in 1995 for infertility
• 2001 CDC/Society of Assisted Reproductive
Technology Statistics
– 107,587 ART cycles performed in 2001
– 40,687 live babies born as a result
Centers for Disease Control and Prevention Assisted Reproductive Technology Success Rates, 2001.
National Center for Health Statistics, Fertility, family planning, and women’s health:
new data from the 1995 National Survey of Family Growth, Report No. 19; Series 23, 1997.
Utilization of Assisted Reproductive
Technologies
Centers for Disease Control and Prevention Assisted Reproductive Technology Success Rates, 2001.
Aging and Female Infertility
• Fertility both in natural and assisted reproductive
cycles declines with age
• The pool of female gametes is fixed and
progressively declines during growth and
development
– Maximum number of oocytes achieved in fetal life is
6-7 million
– 300,000 oocytes present by beginning of puberty
– After age 35 the progressive loss of oocytes becomes
more rapid
Richardson, S. et al. Follicular depletion during the menopausal transition: evidence for accelerated
loss and ultimate exhaustion. JCEM 1987;65:1231-1237.
Aging and Female Infertility
• Quality of oocytes also appears to decline
with increasing age
– Increase in frequency of euploid and aneuploid
spontaneous miscarriage with age
– Meiotic spindle assembly more frequently abnormal in
oocytes from older women
– Greater proportion of degenerative oocytes in older
women isolated from IVF
– Not a problem of age-related uterine changes
Lim A et al. Age-related decline in fertility: a link to degenerative oocytes? Fertility and Sterility 1997;68:265-71.
Battaglia DE et al. Influence of maternal age on meiotic spindle assembly in oocytes from naturally cycling women.
Human Reproduction 1996;11:2217-2222.
Aging and Female Infertility
• Growing proportion of women delay
childbearing into their thirties
• Some lack of awareness of aging as a risk
factor for infertility
– “I know medically you could get pregnant up to the age of 50”
– “I plan to be super fit, super in shape when I’m 40, 50. And if I’m
physically able to do it, then I will have a child at 55”
• Expectations about the potential of
reproductive technologies to circumvent
barriers to fertility
CBSNews.com, August 17, 2003.
Aging and Female Infertility
Centers for Disease Control and Prevention Assisted Reproductive Technology Success Rates, 2001.
Aging and Female Infertility
• The major locus of reproductive aging in
women is the ovarian follicle
• The decline in age-related reproductive
potential correlates with follicular depletion
and diminished quality of the oocyte
• The native oocyte endowment combined
with the reproductive potential of those
oocytes represents a woman’s ovarian
reserve
Premature Ovarian Aging
• Although age predicts loss of reproductive
function, some women behave as if they
are reproductively older than their
chronological age due to a more rapid
than normal depletion of the ovarian
follicular pool
• These women are characterized as having
a clinical condition called diminished
ovarian reserve
Premature Ovarian Aging
• Diminished ovarian reserve has been
associated with:
– Suboptimal response to ovulation induction
– Diminished pregnancy rates after ART
independent of age
– Increased risk of miscarriage and fetal
aneuploidy
Bukulmez O et al. Assessment of ovarian reserve. Curr Opinion in Obstetrics and Gynecology 2004;16:231-237.
Nasseri A et al. Elevated day 3 serum follicle stimulating hormone and/or estradiol may predict fetal aneuploidy.
Fertility and Sterility 1999;71:715-18.
Premature Ovarian Aging
Centers for Disease Control and Prevention Assisted Reproductive Technology Success Rates, 2001.
Premature Ovarian Aging
• The etiology of diminished ovarian reserve is
unknown
– Exposures that cause rapid atresia of ovarian follicles
• Chemotherapy, Radiotherapy
– Ovarian surgery for benign conditions that removes or
damages significant portions of ovarian cortex
– Genetic or acquired mechanisms may predispose
some women to more rapid than normal follicular
atresia
TESTING OVARIAN RESERVE
Testing Ovarian Reserve
• A mathematical model for assessment of a
woman’s reproductive lifespan has been
proposed by a group of investigators from the
University of Andrews, Scotland
– Chronological age and ultrasonagraphic ovarian
characteristics are incorporated into the model to
determine the “reproductive age” of the patient
– Model is designed to tell a patient when she may
transition into menopause
– Time to menopause may not provide an accurate
assessment of years of fertility remaining
Ovarian Reserve
• Reproductive endocrinologists face the
challenge of providing patients with an
adequate prognosis of their fertility
potential at a given age to avoid the
following:
– Exposing patients to expensive and labor-intensive
treatments that have little chance of success
– Falsely discouraging patients from such treatments
that might result in pregnancy
Testing Ovarian Reserve
• Screening for ovarian reserve was an outgrowth
of assisted reproductive technologies
• Tests were initially designed to determine
prognosis of in vitro fertilization in terms of
follicle recruitment and odds of pregnancy
• Few tests have been validated in the general
infertility population
Testing Ovarian Reserve
• Ideal screening test for ovarian reserve should have the
following characteristics:
– Capture all patients who are infertile (high sensitivity)
– Correctly identify those patients who are fertile (high specificity)
– Should test that component of the reproductive axis felt to be
primarily responsible for decrease in fecundity
• In the case of testing ovarian reserve, high positive
predictive value (PPV) and negative predictive value
(NPV) are most important since the accuracy of the test
can only be confirmed after pregnancy has been
attempted
Barnhart K et al. Follicle stimulating hormone as a predictor of fertility. Curr Opinion in Obstetrics and Gynecology 1998;
10:227-32.
Testing Ovarian Reserve
Disease
Test
+
-
+
-
A
B
C
D
• PPV=A/A+B
The probability of not
achieving pregnancy
given a positive test
• NPV=D/C+D
The probability of
achieving pregnancy
given a negative test
Testing Ovarian Reserve
• Day 3 Follicle Stimulating Hormone (FSH)
– First proposed as a screening test in 1988
– FSH is at its maximum in the early part of the
menstrual cycle when estrogen levels are at
their nadir
– Elevated values suggest that ovarian follicles
are not able to adequately suppress FSH
– Values greater than 10mIU/ml correlate with
poor prognosis for those going through IVF
Barnhart K. Curr Opinion in Obstetrics and Gynecology 1998;10:227-32.
Day 3 Follicle Stimulating Hormone
• Advantages:
– Noninvasive
– Relatively inexpensive
– Better predictor of IVF
outcomes than age
alone
– High positive
predictive value (as
high as 97%)
– High specificity (as
high as 98.7%)
Barnhart K. Curr Opinion in Obstetrics and Gynecology 1998;10:227-32.
• Disadvantages:
– High intercycle
variability
– Poor negative
predictive value (as
low as 17%)
– Poor sensitivity (as low
as 8%)
– Positive predictive
value highly sensitive
to population
prevalence of infertility
Clomiphene Challenge Test
• Provocative test of ovarian reserve first
proposed as a screening test in 1989
• Clomiphene Citrate is an estrogen
antagonist at the pituitary gland and
causes a rise in FSH levels
• The test aims to determine if ovarian
follicles are sufficient in quantity and
quality to produce enough hormone to
bring FSH back down to normal
Clomiphene Challenge Test
Clomiphene Challenge Test
• FSH is checked on day 3 of cycle
• Clomiphene Citrate (100 mg) is
administered from days 5-9 of the cycle
• FSH is rechecked on day 10 of cycle
Scott RT et al. Prognostic assessment of ovarian reserve. Fertility and Sterility 1995;63:1-11.
Clomiphene Challenge Test
• Advantages:
• Disadvantages:
– Non-invasive
– Inexpensive
– Sensitivity and
negative predictive
value improved over
basal day 3 FSH
testing alone (26%,
42%)
– Validated in IVF
patients and general
infertility population
Barnhart K. Curr Opinion in Obstetrics and Gynecology 1998;10:227-32.
– Slight decrease in
positive predictive
value compared to day
3 FSH especially when
used in low risk
population (96%)
– Slight decrease in
specificity compared to
day 3 FSH (98%)
Inhibin B
• Hormone produced by granulosa cells of the ovary
• Negative feedback on FSH secretion
• Decreasing inhibin production by aging or rapidly
declining ovarian follicles may explain relationship
between elevated FSH levels and declining fertility
• Early investigations suggest that women with normal
values are 6.8 times more likely to conceive even when
age and day 3 FSH are accounted for
Barnhart K. Curr Opinion in Obstetrics and Gynecology 1998;10:227-32.
Testing Ovarian Reserve
• Optimal test may be an index that
incorporates several serum markers and
non-serologic data
• Interpretation of screening test must take
into consideration the population its being
utilized in
SEARCHING FOR CAUSES
OF DIMINISHED OVARIAN
RESERVE
Diminished Ovarian Reserve
• Main target cell in the ovarian follicle
– Oocyte versus the granulosa cell
• Candidate mediators
– Reactive oxygen species (ROS)
• Ubiquitous and naturally occuring
• Linked to DNA damage, irreversible cell injury and aging in
multiple organ systems
• High follicular fluid ROS levels have been associated with
diminished fertilization and embryo quality in IVF
• Candidate molecular targets
Seino T et al. Eight-hydroxy-2”-deoxyguanosine in granulosa cells is correlated with the quality of oocytes and
embryos in an in vitro fertilzation-embryo transfer program. Fertility and Sterility 2002;77:1184-90.
Telomeres and Telomerase
Telomeres and Telomerase
• A potential mechanism for aging is the
shortening of telomeres with successive cell
divisions
• Cells with critically short telomeres are unable to
divide and may become lost as a result of
apoptosis
• Telomerase maintains telomeric length
preventing replicative senescence but is only
active in germ cells and early embryonic cells
Buys C. Telomeres, Telomerase and Cancer. NEJM 2000;342:1282-63.
Hahn W. Role of Telomeres and Telomerase in the Pathogenesis of Human Cancer. J of Clinical Oncology 2003;21:2034-43.
Telomeres, Telomerase and Aging
• Shortened telomere lengths have been
found in a number of premature aging
syndromes including:
– Hutchinson-Gilford progeria
– Down syndrome
– Werner syndrome
Jennings, B et al. Nutrition, oxidative damage, telomere shortening and cellular senescence: individual or
connected agents of aging? Molecular Genetics and Metabolism, 2000. 71:32-42.
Telomeres, Telomerase and
Premature Ovarian Aging
• Telomerase has been demonstrated in bovine
granulosa cells and its presence is thought to
permit their proliferation supporting normal
follicle development
• It is possible that diminished granulosa cell
telomerase activity in concert with unusually
short telomeres could lead to:
– The sub-optimal proliferation of granulosa cells
surrounding the oocyte
– diminished oocyte viability and/or quality
– an accelerated loss of the oocyte pool
Study Hypotheses
• Telomere length will be shorter in the granulosa
cells of women with decreased ovarian reserve
compared to women other infertility diagnoses
undergoing IVF
• Telomerase activity will be lower in granulosa
cells of women with decreased ovarian reserve
compared to women with other diagnoses
undergoing IVF
Methods
• All patients going through IVF at Penn Fertility
Care are approached for study participation
• Follicular fluid obtained during oocyte retrieval is
used to isolate granulosa cells
• Granulosa cell telomere length and telomerase
activity are determined
– Telomerase activity is assessed using a commercially
available PCR-based assay
– To test for telomere length, Southern blot
electrophoresis method is used (average telomere
length calculated)
Telomeres, Telomerase, Premature
Ovarian Aging
• This investigation examines the possible
association of diminished granulosa cell
telomerase activity/telomeric shortening
and premature ovarian aging for the first
time
• Preliminary results have been promising
for an association between telomerase
inactivity and diminished ovarian reserve
Preliminary Results
Infertility Dx
Telomerase
Positive
Telomerase
Negative
Proportion
(Negative/Total)
1
6
86%
Male Factor
(16)
4
12
75%
Tubal Factor
(9)
6
3
33%
Diminished
Ovarian
Reserve
(7)
Χ² test for trend=5.03 p=0.025
Summary
• Aging represents a significant risk to fertility in
women
• In a subset of women who have diminished
ovarian reserve, a more rapid than normal
decline in oocyte quantity and quality occurs and
these women are at particular risk for infertility
• The use of assisted reproductive technologies is
increasing in this country particularly among
these groups of women
– Expensive of procedures
– Risks associated with ART are not trivial
• Medications, minor surgery, high order multiples
Summary
• Reasonable screening tools exist that provide
insight to the odds of fertility with reproductive
technologies but they are not without limitations
• Public awareness of the effect of age on fertility
and the realistic capabilities of assisted
reproductive technologies may be suboptimal
but the timing of family initiation should
ultimately rest with the individual’s personal
readiness
Future Directions
• To optimize screening tools that can provide
women with an accurate assessment of their
fertility potential
• To improve our understanding of the etiology of
premature ovarian aging
– Inherited genetic underpinnings could be determined
early in a woman’s reproductive life
– Preventable or modifiable exposures may be
discovered that impact the process of premature
ovarian aging
• Environmental exposures
• Behaviors
• Dietary exposures