Transcript Document

Why is Infertility Growing in
Europe?
Is there a link between different disorders of
male reproductive organs and exposure to
chemical compounds?
Henrik Leffers
University Department of Growth & Reproduction,
Rigshospitalet, Copenhagen
Declining conception rates among cohorts
of younger women
Jensen et al. IJA, 2008
2,40
2,00
1,80
1,60
Total fertility rate without ART
1,40
1,20
Year of birth, pregnant w om an
19
80
19
78
19
76
19
74
19
72
19
70
19
68
19
66
19
64
19
62
1,00
19
60
Number of pregnancies
2,20
Declining conception rates among cohorts
of younger women
Jensen et al. IJA, 2008
2,40
2,00
ART
1,80
1,60
Total fertility rate without ART
1,40
1,20
Year of birth, pregnant w om an
19
80
19
78
19
76
19
74
19
72
19
70
19
68
19
66
19
64
19
62
1,00
19
60
Number of pregnancies
2,20
Reproductive health problems
• Human reproductive health problems are very
common, some are increasing
• The man sitting next to you has probably more
than 80% morphologically abnormal sperms (>90
%, if he is a young Dane)
• High demand for ART: almost 8 % of all Danish
children were in 2007 born after IVF, ICSI,
homolog or donor insemination
• In most cases the etiology is really not known,
although we use terms as ”oligozoospermia” and
”ovarian failure”
• Do endocrine disrupters play a role?
Structure of the Testis
Oct-4 expression in CIS cells (adult, subfertile male)
Gene expression in CIS cells in relation to germ cell differentiation
Birth
ESC
CIS:
PGC
Gonocyte
Puberty
Infantile
sp-gonium Sp-gonium
Spermatocytes
Spermatids
NANOG:
OCT-4:
AP-2
TRA-1-60:
PLAP:
KIT:
p53:
Cyclin D2:
CHK-2 :
TSPY:
MAGE A4:
NY-ESO-1:
DAZL 1:
Hiwi:
VASA:
IMP-1:
Pluripotency, self-renewal, survival in
undifferentiated stage
Regulation of cell cycle,
DNA repair (mitotic division)
Germ cell
specific
e.g. RNA
processing
Rates in testis cancer
Lessons from recent biological and
epidemiological research on testis cancer
• Testis cancer is a sensor for poor reproductive health
(incl. cryptorchidism, poor semen quality)
• Testis cancer is of fetal origin. Therefore, a search for
causal factors should be directed towards adverse
effects on the fetal testis
•Increasing incidence of testis cancer. Other male
reproductive problems are also becomming more
common!
Perinatal exposure of Rats to
Phthalates (DEHP, DBP)
May cause a ”phthalate syndrome” in male
offspring, including
• Leydig cell abnormalities
• Dysgenesis of Leydig cells and seminiferous
tubules
• Hypospadias
• Undescended testis
• Spermatogenic failure and infertility
(Several papers from Paul Foster’s, Earl Gray’s, Rao
Veeramachaneni’s and Richard Sharpe’s groups)
Phthalate Effects on Testis
Dysgenetic areas in the testes on d4
postnatal after in utero exposure to
DBP (500 mg/kg/day) Fisher et al.
Hum Reprod, 2003)
Control
Brown = smooth muscle
actin
DBP
The Rat Phthalate Syndrome Resembles Human Problems
Does Chemical Exposure Affect the Human Fetus?
• Association between excretion of phthalates in
pregnant women’s urine and ano-genital distance in
newborn boys, Swan et al. 2005
Does Chemical Exposure Affect the Fetus?
• Association between excretion of phthalates in pregnant
women’s urine and ano-genital distance in newborn boys,
Swan et al. 2005
• Association between Phthalate levels in breats milk and
subtle changes in hormone levels in 3 month old boys, Main et
al. 2006
Collection of breast milk
• Breast milk: post nataly month 1, n=130
• Serum samples from the children at 3 months,
n= 96
Changes in boys hormone levels associated with 10
fold higher phthalate levels in the milk
• mEP, mBP:
+ 15,+8 % SHBG
• mBP:
- 15% free testosterone
• mMP, mEP, mBP:
+ 26, +19, +18 %
LH /free testosterone ratio
• miNP:
+ 97% LH
Main KM et al. EHP 2006
Does Chemical Exposure Affect the Fetus?
•
Association between excretion of phthalates in pregnant women’s
urine and ano-genital distance in newborn boys, Swan et al. 2005
•
Association between Phthalate levels in breats milk and subtle
changes in hormone levels in 3 month old boys, Main et al. 2006
•
Persistent pesticides in breast milk and cryptorchidism in the sons,
Damgaard et al. 2006
•
Flameretardants in breast milk and chryptorchidism in the sons,
Main et al. 2007
Ongoing project: Uptake of phthalates
and parabens through skin
• Comparisons between applications of ”basis
lotion” with and without 2% phthalates and
2% parabens
• Bloodsampling during 24 hours
Mono-butyl-phthalate in serum during
24 hours
mBP
µg/L
70
60
50
40
30
20
10
0
T=0
T=1
T=2
T=3
control week
T=4
T=24
exposure week
Janjua NR, Mortensen GK, Skakkebæk NE, Wulf HC, Andersson AM, 2008.
It seems safe to conclude….
• The phthalates DEP, DBP, and BuP are
rapidly taken up through the skin after
topical application.
• Although these compounds have a high
clearance rate some accumulation by every
day use can occur.
• Normal use of cosmetics and skin care
products containing these compounds is
likely to result in recurrent serum spikes of
the parent compounds and their metabolites.
Janjua NR, Mortensen GK, Skakkebæk NE, Wulf HC, Andersson AM, 2008.
Effects of Mixtures of
Endocrine Disrupting
Substances
Ulla Hass
Dept. of Toxicology and Risk Assessment, National Food Institute, Danish Technical
University, Denmark
Design of EDEN studies
Anti-androgen alone
or in mix
Via milk
Via placenta
Birth
Pups: AGD, nipple retention,
reproductive organs, gene
expression
Young adults:
Malformations, semen
quality, behaviour
Malformations of external reproductive
organs in adult male offspring
1) Completely split
penis and visible os
penis, i.e. marked
hypospadia
2) Blind vaginal
opening
Something from Nothing
0% + 0% + 0% ~ 60%
Christiansen et al 2008, Int. J. Androl. 31
Differences in prevalence of genital
abnormalities between Denmark and
Finland
(From Boisen et al. Lancet 2004;Boisen et al. JCEM 205)
10,00
9,00
8,00
7,00
6,00
5,00
4,00
3,00
2,00
1,00
0,00
Denmark
Finland
cryptorchidism
at birth
cryptorchidism
at 3 months
hypospadias
Geographic association between abnormalities
in male reproductive health
Denmark
•
•
•
•
•
High incidence of
testicular cancer
High prevalence of
cryptorchidism
High prevalence of
hypospadias
Low sperm counts
Smaller testes as
newborns and lower
inhibin-B levels
•
•
•
•
•
•
Finland
Low incidence of
testicular cancer
Low prevalence of
cryptorchidism
Low prevalence of
hypospadias
High sperm counts
Bigger testes as
newborns and higher
inhibin-B levels
Can Different Environmental Exposures between
Denmark and Finland explain the Different
Reproductive Health Patterns?
• More Danish women smoke and drink during
pregnancy (Jensen et al. Am J Epidemiol.
2004)
• Associations to different exposures to EDs?
Danish
Chemicals in breast milk from
mothers of newborn boys
Finnish
*: p<0.05
p,p'-DDE
other persistent pesticides
30
200
150
ng/g
ng/g
20
100
10
50
0
0
p,p'-DDE *
DDT *
HCH
HCB *
brominated flame retardents
oxychlordane
dieldrin *
phthalate monoesters
3
150
2
100
ug/L
ng/g
endosulfan-I
1
50
0
0
BDE 47
BDE 153 *
mEHP *
miNP
cis-HE
Conclusions
• We are all exposed to a mixture of endocrine disrupters
• ”Antiandrogenic” agents may be as important as
chemicals with estrogenic actions
• Evidence that testicular cancer, cryptorchidism,
hypospadias and poor semen quality can be linked
through a fetal mechanism causing testicular dysgenesis
(TDS syndrome)
• We are beginning to see associations between fetal
exposures of humans to some endocrine disrupters and
symptoms of TDS
• Causal relationships between EDs and reproductive
symptoms have been established in experimental
animals, but not in humans
• Current ED research is focussed on the issue of possible
additive effects of mixtures of different chemicals with
different actions
Thanks to
• Niels E. Skakkebæk, Niels Jørgensen,
Katharina Main, Anna-Maria Andersson,
Ewa Rajpert-De Meyts, Anders Juul and
several of their Ph.D. students
• Jorma Toppari, Finland
• Other European collaborators
• And many others
Testicular Dysgenesis
Syndrome
Environmental factors
incl. endocrine
disrupters
REDUCED SEMEN
QUALITY
DISTURBED
SERTOLI
CELL
FUNCTION
IMPAIRED
GERM
CELL
DIFFERENTIATION
CIS
TESTICULAR
DYSGENESIS
TESTICULAR
CANCER
HYPOSPADIAS
DECREASED
LEYDIG CELL
FUNCTION
Genetic defects
incl. 45,X/46,XY and
point mutations
ANDROGEN
INSUFFICIENCY
TESTICULAR
MALDESCENT