Transcript Adverse Perinatal Outcomes associated with Environmental

Adverse Perinatal Outcomes
associated with Environmental
and Dietary Factors
Phillip V. Gordon MD PhD
Elsie Shaefer Chair, Neonatology
Assistant Chair of Pediatrics
Tulane School of Medicine
What you should get from this talk:
• Understand how diet affects prenatal outcomes
• There are several pollutants with compelling
links to birth defects and/or prematurity
• Know which regions of the country have the
worst perinatal outcomes (and likely why)
• Incorporate this knowledge into your clinical
practice and patient counseling
Known Dietary Associations with
Common Adverse Perinatal Outcomes
• Folate deficiency
▫ Neural Tube Defects
▫ Congential Heart Defects
No prenatal vitamins
▫ Cleft Lip and Palate (weak association)
Western diet  type II diabetes
▫ Congenital Heart Defects
▫ Neural Tube Defects
▫ Small for Gestational Age
Folate Deficiency  O2 Free Radicals
X
Mitochondrial
Uncoupling
Mitochondrial
uncoupling increases
free radicals and kills
stem cells
Particularly vulnerable fetal cell types: neural crest cells & cardiac stem cells
Folate Deficiency & Neural Tube Defects
MTRR 66A>G and MTHFR 677C>T are the only two polymorphisms definitively
associated with folate metabolism associated with NTDs. However, MTHFR 677C is
thought to be prevalent in >½ the world population and a single polymorphism
reduces enzymatic efficiency by 50%
What is the evidence that Folate
rescues neural tube fusion failure?
Meta-analysis for the reduction in NTD
Meta-analysis for the reduction in NTD
recurrence risk observed with periconceptional occurrence risk observed with periconceptional
folic acid supplementation
folic acid supplementation
x5
x2
Folic acid, methylation and neural tube closure in humans. Blom HJ. Birth
Defects Res A Clin Mol Teratol. 2009 Apr;85(4):295-302.
The Etiology of Conotruncal Defects
The secondary heart field provides myocardium and smooth muscle cells to the
arterial pole. Cells of the secondary heart field were labeled at stage 15 (A–D) with
a mixture of DiI and rhodamine (red). (A) 4 h after injection at stage 15; labeled
cells are located in the ventral floor of the pharynx caudal to the outflow tract. (B)
24 h after injection; labeled cells translocated to the base of the outflow tract. (C)
Stage 22 heart 48 h after right secondary heart field injection; left view of the
outflow shows labeled cells located in the distal outflow myocardium (arrow) on
the left side. (D) Section through outflow of heart in panel (C) stained with antirhodamine. Labeled cells are incorporated into the myocardial wall (arrow).
Secondary heart field contributes myocardium
and smooth muscle to the arterial pole of the
developing heart. Waldo KL, Hutson MR, Ward
CC, Zdanowicz M, Stadt HA, Kumiski D, Abu-Issa
R, Kirby ML. Dev Biol. 2005 May 1;281(1):78-90.
Diabetes and Conotruncal Defects
CNC cell migration, apoptosis, and
outflow tract septation in Pax3LacZ/1
embryos of nondiabetic and diabetic mice.
The approximate area of embryos shown in
Figures 1–4 is indicated within the boxed
area of the embryo diagram. (A–D)
Pax3LacZ/1 embryos were recovered
on day 9.5 from diabetic or nondiabetic
FVB females that had been crossed with
Pax3LacZ/1 males. Embryos were reacted
with X-GAL (A,B) to visualize CNC cells, or
reacted with a wholemount TUNEL
procedure (C,D) to visualize apoptotic
nuclei. The fluorescence overlay of a
differential interference contrast (DIC)
image of the embryos is shown in the
insets. (A,C) Pax3LacZ/1
embryos of nondiabetic mice. (B,D)
Pax3LacZ/1 embryos of diabetic mice. In
image (A) the otic pit is marked by an
asterisk, the first somite is marked by §,
and the migrating CNC are
marked by arrows. (E,F) Pax3LacZ/1
fetuses were recovered on day 16.5 from
crosses of diabetic or nondiabetic FVB
females with Pax3LacZ/1 males and cardiac
outflow tracts were examined. Images of
fetal hearts from (E) nondiabetic
pregnancy show the normal outflow tract
arrangement, whereas (F) from a diabetic
pregnancy show typical outflow tract
defects in which the aorta and left
pulmonary artery have not correctly
separated into distinct vessels (see
arrowhead).
Oxidative stress during diabetic pregnancy
disrupts cardiac neural crest migration and
causes outflow tract defects. Morgan SC, Relaix
F, Sandell LL, Loeken MR.
Birth Defects Res A Clin Mol Teratol. 2008
Jun;82(6):453-63.
Truncus Arteriosus
Diabetes and Conotruncal Defects
CNC migration in embryos following
induction of oxidative stress without or with
antioxidants. FVB females were crossed
with either Pax3LacZ/1 or Pax3GFP/1 males.
On day 7.5 of pregnancy, the females were
injected with antimycin A (AA) or propylene
glycol (PG) as a control. AA-treated
pregnancies were also administered GSH-EE
on day 7.5, or received supplemental dietary
vitamin E succinate beginning on day 0.5.
Embryos were obtained on day 9.5.
Pax3LacZ/1 embryos were reacted with XGAL to visualize CNC migration (A–D), or
subjected to a whole-mount TUNEL assay to
visualize apoptosis (E–H). Pax3GFP/1
embryos were examined by confocal
microscopy (I–L). (A,E,I) Embryos from PGtreated pregnancies. (B,F,J) Embryos from
AA-treated pregnancies. (C,G,K) Embryos
from AA plus GSH-EE-treated pregnancies.
(D,H,L) Embryos from AA-treated
pregnancies supplemented with vitamin E.
The location of absent CNC cell migration is
marked by an asterisk. Arrows point to
between the two streams of LacZ- or GFPpositive CNC cells.
What about folate and CHD?
Conotruncal
defects
Changes in frequencies of select
congenital anomalies since the onset of
folic acid fortification in a Canadian
birth defect registry. Godwin KA,
Sibbald B, Bedard T, Kuzeljevic B,
Lowry RB, Arbour L. Can J Public
Health. 2008 Jul-Aug;99(4):271-5.
>
Non
conotruncal
defects
Conotruncal
defects
Non
conotruncal
defects
Oxidative Stress and Windows of Vulnerability
What have we learned so far?
• Folate deficiency and type II diabetes both exacerbate fetal
oxidative stress, which disrupts stem cell proliferation
• Polymorphisms in genes that produce enzymes for folate
metabolism lead to increased susceptibility to folate
deficiency, worsen oxidative stress, and predispose the fetus
to NTD or CHD.
• The greatest window of vulnerability is during the first 6
weeks of pregnancy (hence the need to take PRENATAL
vitamins)
• MOST IMPORTANTLY! If you’ve had one child with a NTD or
CHD, it is critical that you take prenatal vitamins with folate for
the next
Cleft Lip and Palate (CL/P)
Individuals with various types of orofacial
clefting with known and unknown etiologies.
Nearly all variants of CL/P have now been
associated with some form of mutation, deletion
or polymorphism within the interferon regulator
factor-6 gene. Small effects of diet and smoking
have been shown on the incidence of nonsyndromic CL/P, likely consistent with effects
upon polymorphic susceptibilities. Folate has
not reduced the incidence of CL/P.
Gastroschisis and Rising Incidence
Prevalence of gastroschisis and associated hospital time continue to rise in
neonates who are admitted for intensive care. Clark RH, Walker MW, Gauderer
MW. J Pediatr Surg. 2009 Jun;44(6):1108-12.
Kelly D. Mattixa,
,
, Paul D. Winchesterb and L.R. “Tres” Scherera
What is causing Gastroschisis?
Maternal asthma medication use and the risk of gastroschisis.
Lin S, Munsie JP, Herdt-Losavio ML, Bell E, Druschel C, Romitti PA, Olney R; National
Birth Defects Prevention Study. Am J Epidemiol. 2008 Jul 1;168(1):73-9.
(1)
(2)
Maternal use of bronchodilators, antiinflammatories,
and both and the risk of gastroschisis, National Birth
Defects Prevention Study, 1997–2002
Cases
Controls
Crude
95%
Adjuste
95%
odds confidence d odds confidence
ratio
interval
ratio*
interval
No.
%
No.
%
17
4.53
96
2.38
1.94
1.14, 3.29
2.06
1.19, 3.59
358 95.47 3,932 97.62
1.00
Referent
1.00
Referent
1.20
0.55, 2.64
2.00
0.88, 4.51
1.00
Referent
1.00
Referent
0.49
2.30
0.78, 6.79
2.69
0.87, 8.28
355 98.89 3,873 99.52
1.00
Referent
1.00
Referent
Bronchodilators
Abdominal Wall Defects
Indiana
Yes
No
Antiinflammatories
Yes
No
Mid West & U.S.
Incidence of abdominal wall defects is related to
surface water atrazine and nitrate levels. Mattix KD,
Winchester PD, Scherer LR. J Pediatr Surg. 2007
Jun;42(6):947-9.
Bronchodilators
and
antiinflammatories
Yes
No
7
1.85
63
1.55
371 98.15 4,003 98.45
4
1.11
19
Its not just Gastroschisis…
Acta Paediatr. 2009 Apr;98(4):664-9. Agrichemicals in
surface water and birth defects in the United States.
Winchester PD, Huskins J, Ying J.
A statistically significant increased risk was found for any birth defect and also specifically for spina bifida,
circulatory, tracheal, gastrointestinal, urogenital, musculoskeletal anomalies, cleft lip, adactyly, clubfoot and
Down's syndrome in women with LMPs between April and July in the United Sates
*
Adjusted for maternal age, ethnicity, educational level, smoking, folic acid, and any of the
How does Atrazine cause Birth Defects?
It causes Metabolic Syndrome  Diabetes
Chronic exposure to the herbicide, Atrazine, causes mitochondrial dysfunction and insulin resistance.
Lim S, Ahn SY, Song IC, Chung MH, Jang HC, Park KS, Lee KU, Pak YK, Lee HK. PLoS One. 2009;4(4):e5186
Atrazine is also associated with SGA birth
Geometric mean of Atrazine levels in raw
water by month (μg/l, in the y axis) and
lower 95% confidence interval, estimated
from an analysis of variance adjusted for
year and water distribution unit.
Adjusted OR* of small-for-gestational-age
status, by the number of months of the
third trimester that overlapped with the
May–September period
OR, odds ratio; 95% CI, 95% CI; n, number of small for
gestational age newborns.
*Obtained from logistic regression adjusting for sex of the
newborn, maternal age, and geometric mean atrazine level in
May–September.
No. months of the 3rd trimester in May–September
OR (95% CI)
Atrazine in municipal drinking water and risk of low birth
weight, preterm delivery, and small-for-gestational-age status.
Villanueva CM, Durand G, Coutté MB, Chevrier C, Cordier S.
Occup Environ Med. 2005 Jun;62(6):400-5.
n
0 month 1.00
83
1 month 1.25 (0.84 to 1.86)
39
2 months 1.36 (0.96 to 1.93)
57
3 months 1.48 (1.04 to 2.09)
59
p trend 0.019
Following the Atrazine water cycle
SGA incidence peaks in the states where
Atrazine had the longest windows of effect
upon Amphibian birth defects
The Mississippi Delta also has maximum peak
exposure because of the water cycle (and so
might have a high incidence of birth defects)
Watershed Regressions for Pesticides (WARP) Atrazine Model
http://infotrek.er.usgs.gov/warp/
Unfortunately, we don’t really have a reliable
way to test this hypothesis, because these two
states did a poor job of tracking birth defects
prior to Hurricane Katrina and things haven’t
improved much since
healthyamericans.org
2002
Diabetes also maps tightly with SGA
Like Atrazine, diabetes can cause
both birth defects and SGA births
How does diabetes cause both birth defects and SGA birth?
Transcription Change in Response to Diabetes
Epigenetic Mechanisms
hyperglycemia
altered methylation
and acetylation of
glucose transporter
promoter sites (life
long insulin
resistance)
glycolysis pathway shunting
increased free radicals
aberrant glycoslation
oxidative damage from
mitochondria, particularly
in placenta (ratty placenta
leading to SGA)
free radical disruption
of beta cell stem cells
(life long insulin
resistance and
potentiation of
diabetes in subsequent
generations)
Maternal diabetes alters transcriptional programs in the developing embryo.
Pavlinkova G, Salbaum JM, Kappen C. BMC Genomics. 2009 Jun 18;10:274.
Type II Diabetes has dietary risk factors too
(and this should be part of our prenatal counseling)
What have we learned now?
• Cleft lip and palate is poorly associated with environmental and dietary risks
• Gastroschisis incidence has been rising and two environmental risk factors have been
associated with this increase: 1) bronchodialators, 2) Atrazine (possibly all triazines)
• Atrazine has been temporally associated with a wide number of birth defects as well as
SGA births and has been demonstrated to be a mitochondrial inhibitor that induces insulin
resistance and metabolic syndrome in rats with low level, chronic dosage (thereby
providing a mechanism)
• Type II diabetes and SGA birth have close geographic overlap, with Atrazine having the
potential to be an important adjunct risk for SGA birth.
• Finally, when counseling mothers about all this, we have to remember the basics, like diet,
health benefits and risk reduction of breast feeding, and ….
Appropriate hydration using a reliable water source
?
OR
Water from the bayou
Bottled water
Hypospadias Incidence is also Increasing
We have to be careful about associations. For example,
just because two things go up simultaneously (like sales
of bottled water and hypospadias) does not mean they
are related in a causal manner.
Phthalates most look like?
diisodecyl phthalate
dibutyl phthalate (DBP)
Phthalates are everywhere and they do affect humans
Phthalates were first introduces in the 1930s as
plasticizers
Phthalates are associated with decreased
urogenital distance and increased incidence of
cryptorchidism
Increased maternal breast milk concentrations
of phthalates are associated with decreased
neonatal androgen levels
Phthalates have been used to make baby bottles,
IV bags, toys, syringes, tubing, containers, pill
coatings, piping, building materials and sex toys.
They are found literally everywhere in our lives.
= Phthalate Susceptible Pathways during Male
Reproductive Tract Development
Mullerian Inhibiting
Substance
Types of
Hypospadias
Mullerian Duct
Regression
Glanular
Sertolli Cell
INSL3
Subcoronal
Trans-Abdominal
Descent of the Testes
Anterior
(50%)
Distal
Penile
Leydig Cell
Testosterone
MidShaft
Inguino-Scrotal
Descent of the Testes
5-alpha
reductase
Wolffian Duct
Differentiation
Epididymus
Vas Deferens
Seminal Vescicles
Dihydroxy Testosterone
Genital Tubericle
Differentiation
Male Genitalia
Urogenital Sinus
Differentiation
Prostate Gland
Middle
(30%)
Proximal
Penile
Penoscrotal
Posterior
(20%)
Scrotal
Perianal
(approximately 10% of all hypospadias
have undescended testes)
The best option is to drink filtered water
Well, if you can’t drink the water, can
you at least breathe the air?
Poor air quality has been
associated with poor perinatal
outcomes:
sulfur dioxide, benzene, fine
particulate matter associated
with car exhaust, and tobacco
smoke have all been associated
with SGA births
Car exhaust has more recently
been associated with prematurity
and preeclampsia
There is a temporal relationship between
car exhaust and preterm birth
Five-county metropolitan Atlanta, population density
according to the 2000 Census and location of
ambient air quality monitoring stations
Jefferson
Ambient air pollution and preterm birth: a time-series analysis. Darrow LA,
Klein M, Flanders WD, Waller LA, Correa A, Marcus M, Mulholland JA,
Russell AG, Tolbert PE. Epidemiology. 2009 Sep;20(5):689-98
Tucker
Georgia Tech
South DeKalb
Monitor-specific adjusted risk ratios (circles) and
95% CIs (vertical bars) for preterm birth associated with a 5
ppb increase in NO2 levels in the preceding 6 weeks. Adjusted
for long term trends, seasonal trends, race/ethnicity, marital
status, education, gestational week and interaction between
gestational week and maternal characteristics.
There is a proximity relationship between
car exhaust and SGA birth
A cohort study of trafficrelated air pollution impacts Measure
on birth outcomes.
Brauer M, Lencar C, Tamburic L,
Koehoorn M, Demers P, Karr C.
Environ Health Perspect.
2008 May;116(5):680-6.
< 150 m
highwayb
or < 50 m
major roadc
< 50 m
highway
< 150 m
highway
< 50 m
major road
< 150 m
major road
No. of SGA
Crude OR
cases (% of
(95% CI)
total subjects)
Adjusteda
OR (95% CI)
1,218
(1.73)
1.01
0.99
(0.95–1.08) (0.92–1.06)
176
(0.25)
413
(0.59)
842
(1.20)
1,611
(2.29)
1.31
1.26
(1.12–1.54) (1.07–1.49)
0.96
0.93
(0.86–1.07) (0.83–1.03)
1.04
1.03
(0.97–1.13) (0.95–1.12)
1.05
1.04
(0.99–1.12) (0.98–1.11)
There is a dose response relationship
between car exhaust and prematurity
Association between local traffic-generated air pollution and
preeclampsia and preterm delivery in the south coast air basin
of California. Wu J, Ren C, Delfino RJ, Chung J, Wilhelm M,
Ritz B. Environ Health Perspect. 2009 Nov;117(11):1773-9.
Are we ready for this?
Poor air quality does not show national
geographic parallels to prematurity
Poor air quality does not show national
geographic parallels to SGA birth
These maps suggest that chronic poor air quality is
either not a risk factor or not as great a risk factor
as close and chronic proximity to car exhaust
What environmental and dietary risk factors should we really and
truly be concerned about in our clinical practice environment?
1. Prenatal vitamins with folate – no brainer, mandatory for a mother who has already had a
child with a NTD or CHD (both of which are declining due to folate supplements)
*400 mcg before, 600 mcg during pregnancy, up to 1000 mcg for high risk
2. CL/P – probably not environmental or dietary (although vitamins and smoking cessation
never hurt anybody). This information can ease maternal guilt.
3. Gastroschisis and hypospadias incidence are rising. Asthmatic mothers need to be in good
control to minimize bronchodilator abuse. Well water is probably not a good idea in
agricultural or Mississippi Delta regions, especially if they are showing evidence of
metabolic syndrome habitus. Phthalate is a concern, particularly if they have an unusual
source of exposure (pregnant cancer patient and IV bags). Pregnant women or women
planning to get pregnant should avoid plastic products with this sign:
4. Close, chronic exposure to car exhaust is a risk factor for prematurity and SGA birth. It is
probably time for us to start asking about living over a garage, working as a mechanic,
driving a jalopy with a ruptured manifold, < 50 meters from a highway etc. General
exposure, not so much – for now.
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