latest advances in understanding preeclampsia · latest advances in understanding preeclampsia ......
TRANSCRIPT
![Page 1: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/1.jpg)
Latest Advances in
Understanding Preeclampsia
Yoav Yinon, MD
Department of Obstetrics and Gynecology
Sheba Medical Center
![Page 2: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/2.jpg)
Preeclampsia
• Worldwide prevalence: 5-8%
• Leading cause of maternal mortality in
developing countries:
>60,000 maternal deaths/yr
• Major cause of perinatal morbidity and
mortality
![Page 3: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/3.jpg)
Preeclampsia-Complications
• Acute renal failure
• Placental abruption
• Pulmonary edema
• Acute liver injury
• Hemolysis
• Thrombocytopenia
• Seizures
Maternal Fetal
• IUGR
• Oligohydramnios
• Prematurity
• Perinatal death
![Page 4: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/4.jpg)
Criteria for Diagnosis
• SBP ≥ 140 mmHg or DBP ≥ 90 mmHg that
occurs after 20 weeks of gestation in a
woman with previously normal BP
• Proteinuria defined as ≥ 0.3 g in a 24h
urine specimen or ≥ 1+ proteinuria
detected by dipstick
![Page 5: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/5.jpg)
Criteria for Diagnosis
• In the absence of proteinuria, new onset
hypertension with new onset of any one of
the following:
– Thrombocytopenia
– Renal insufficiency
– Impaired liver function
– Pulmonary edema
– Cerebral or visual problems
![Page 6: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/6.jpg)
Preeclampsia
Disease of Theories
Two-stage theory:
Preeclampsia is a systemic syndrome that originates
in the placenta and is characterized by maternal
endothelial dysfunction
![Page 7: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/7.jpg)
Risk Factors
• Chronic hypertension/renal disease
• Diabetes
• Connective tissue disease
• Thrombophilia
• Advanced maternal age
• Obesity
• Multifetal gestation
• Chromosomal abnormality (triploidy, trisomy 13)
• Smoking- reduced risk
![Page 8: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/8.jpg)
Risk Factors
• Nulliparity
• Multiparous women pregnant with a new partner
• Increased interpregnancy interval
• Preeclampsia in a previous pregnancy
• Family history of preeclampsia
• Partner who fathered preeclamptic pregnancy with another
woman
![Page 9: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/9.jpg)
Role of Placenta
• Preeclampsia only occurs in the presence of placenta and almost always remits after delivery
• Severe preeclampsia is associated with pathological evidence of placental hypoperfusion and ischemia
• Abnormal uterine artery Doppler is observed before the clinical onset of preeclampsia
![Page 10: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/10.jpg)
Normal Pregnancy
![Page 11: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/11.jpg)
Preeclampsia- Abnormal Placentation
![Page 12: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/12.jpg)
anchoring villus
endovasculartroph.-cells
BP
Dec.
Myo.
endothelialcells
interstitialtroph.-cells
non invadedmedia
topofspiral-artery
topofspiral-artery
border between prolif. and invas. troph.-cells
Healthy Pregnant Patients Preeclampsia
Courtesy of Dr. F. Reister
![Page 13: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/13.jpg)
Preeclampsia- Abnormal Placentation
• Trophoblastic invasion
• Arteries are poorly remodeled
• Capacity of uteroplacental circulation
![Page 14: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/14.jpg)
Adapted from Pre-eclampsia, by Baker & Kingdom
Placental blood flow and vascular impedance
![Page 15: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/15.jpg)
Uterine artery Doppler
Non-
pregnant
At 25 wks
![Page 16: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/16.jpg)
Failure of uterine artery transformation
Normal: Non-pregnant
Abnormal: Pregnant at 25 weeks
![Page 17: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/17.jpg)
Maternal endothelial damage
• Although preeclampsia appears to begin in the placenta, the target organ is maternal endothelium
• Serum markers of endothelial activation are deranged in women with PE
• Circulating factors originating from the placenta lead to endothelial dysfunction
![Page 18: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/18.jpg)
Maternal endothelial dysfunction
• Hemodynamic changes:
vasoconstriction, increased vascular resistance, decreased cardiac output
• Renal pathology:
Glomerular endotheliosis
• Cerebral edema:
Vasogenic cerebral edema and infarctions in the subcortical white matter (PRES)
![Page 19: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/19.jpg)
Pathogenesis: The role of
Angiogenic Factors
• Imbalance of endogenous angiogenic factors play a key role
• Increased expression of soluble fms-like tyrosine kinase-1 (sFlt1) associated with decreased placental growth factor (PLGF)and VEGF signaling
• VEGF deficiency is responsible for proteinuria and glomerular changes
![Page 20: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/20.jpg)
Pathogenesis: The role of
Angiogenic Factors
• Soluble endoglin (sEng), which binds and antagonizes TGF-b, is upregulated in preeclampsia
• Endoglin is expressed at high levels in the syncytiotrophoblast cells
• Levels of endoglin are increased in preeclamptic placentas
![Page 21: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/21.jpg)
Normal Preeclampsia
![Page 22: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/22.jpg)
sFlt-1
PLGF
VEGF
Maynard et al, JCI 2003
![Page 23: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/23.jpg)
The antiangiogenic properties of serum from preeclamptic
patients are due to blockade of VEGF and PLGF by
endogenous sFlt-1
Maynard et al, JCI 2003
![Page 24: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/24.jpg)
sFlt-1 inhibits VEGF and PLGF-induced
vasodilatation of renal microvessel
sFlt-1 in preeclamptic patients might
oppose physiologic vasorelaxation
Maynard et al, JCI 2003
![Page 25: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/25.jpg)
sFlt-1 induces glomerular endotheliosis
Maynard et al, JCI 2003
![Page 26: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/26.jpg)
VEGF and Preeclampsia
• VEGF is highly expressed by glomerular podocytes
• VEGF receptors are present on glomerular endothelial cells
• Podocyte-specific VEGF knockout mouse resulted in renal disease characterized by proteinuria and glomerular endotheliosis (Eremina et al, JCI 2003)
![Page 27: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/27.jpg)
VEGF and Preeclampsia
• In humans, anti-angiogenesis cancer trials with anti-VEGF antibodies have led to proteinuria and hypertension
(Eremina et al, NEJM 2008)
• VEGF may be important in maintaining the health of fenestrated endothelium
• VEGF deficiency is likely responsible for proteinuria and glomerular endotheliosis
![Page 28: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/28.jpg)
PLGF and Preeclampsia
• A potent angiogenic growth factor
• Amplify VEGF signaling
• During pregnancy, inhibition of both
PLGF and VEGF is necessary to
produce preeclampsia-like changes in
pregnant rats
![Page 29: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/29.jpg)
Circulating sFlt-1 levels and the risk of preeclampsia
Levine et al, NEJM 2004
![Page 30: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/30.jpg)
Circulating PLGF levels and the risk of preeclampsia
Levine et al, NEJM 2004
![Page 31: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/31.jpg)
Levine et al, NEJM 2004
Circulating angiogenic factors and the risk of
preeclampsia
![Page 32: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/32.jpg)
Summary
• sFlt-1 is upregulated in preeclampsia
• Increased sFlt-1 in preeclamptic patients is associated with decreased circulating levels of VEGF and PLGF, resulting in endothelial dysfunction in vitro
• VEGF and PLGF cause microvascular relaxation of rat renal arterioles in vitro that is blocked by sFlt-1
• Administration of sFlt-1 to pregnant rats induces hypertension, proteinuria and glomerular endotheliosis
• Excess circulating sFlt-1 contributes to the pathogenesis of preeclampsia
![Page 33: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/33.jpg)
![Page 34: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/34.jpg)
Endoglin in Preeclampsia
![Page 35: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/35.jpg)
Endoglin in Preeclampsia
• sEng levels were three-,
five- and tenfold higher
in women with mild
preeclampsia, severe
preeclampsia and
HELLP syndrome
respectively compared
to preterm controls
Venkatesha et al, Nature Medicine 2006
![Page 36: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/36.jpg)
Endoglin in Preeclampsia
Venkatesha et al, Nature Medicine 2006
• VEGF and TGFß1
had additive effects
on vasodilatation
which were blocked
by the combination of
sEng and sFlt1
![Page 37: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/37.jpg)
In vivo effects of sEng and sFlt1
Venkatesha et al, Nature Medicine 2006
![Page 38: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/38.jpg)
Soluble Endoglin in Preeclampsia
• At 17-20 weeks soluble
endoglin levels were
significantly higher in
women in whom preterm
PET later developed
• At 25-28 weeks levels
were significantly higher in
women in whom term PET
later developed
Levine et al, NEJM 2006
![Page 39: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/39.jpg)
Soluble Endoglin in Preeclampsia
• An increased level of sEng
was usually accompanied
by an increased ratio of
sFlt1:PLGF
• The risk of preeclampsia
was greatest among women
in the highest quartile for
both biomarkers
Levine et al, NEJM 2006
![Page 40: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/40.jpg)
Summary
• Endoglin is elevated in the serum of preeclamptic women, correlates with disease severity and falls after delivery
• sEng inhibits formation of capillary tubes in vitro and induces vascular permeability and hypertension in vivo
• Co-administration of sEng and sFlt1 to pregnant rats leads to severe preeclampsia including HELLP syndrome
• sEng leads dysregulated TGF-b signaling
• sEng may act in concert with sFlt1 to induce severe preeclampsia
![Page 41: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/41.jpg)
Pathogenesis
• The molecular basis for placental
dysregulation of these anti-angiogenic
factors remains unknown
• Hypoxia is likely to be an important regulator
Is the shallow cytotrophoblast invasion a consequence or
cause of placental ischemia/ hypoxia?
![Page 42: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/42.jpg)
Effect of Oxygen on Endoglin Expression in
Villous Explants
0
0.5
1
1.5
2
2.5
3
3.5
3% 20%
*P<0.05
*
qRT-PCR Analysis
(oxygen concentration)
En
g t
ran
scrip
t fo
ld c
han
ge
0
1
2
3
4
3% 8% 20%
3% 8% 20%
Eng
sEng
*
*P<0.05
(oxygen concentration)En
g p
rote
in l
evel
s fo
ld c
han
ge
Yinon et al. Am J Path 2008
![Page 43: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/43.jpg)
Pathogenesis: Other pathways
• Renin-angiotensin-aldosterone
• Endothelin-1
• Immunological intolerance
• Oxidative stress
• Genetics
![Page 44: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/44.jpg)
Renin- angiotensin pathway
• In normal pregnancy renin, aldosterone
and angiotensin are increased
• These hormones are suppressed relative
to normal pregnancy in preeclampsia
• Women with preeclampsia have increased
vascular responsiveness to angiotensin II
![Page 45: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/45.jpg)
Renin- angiotensin pathway
• Patients with PE develop agonistic
autoantibodies against the angiotensin II
AT1 receptor (Wallukat et al, JCI 1999)
• AT1 receptor autoantibodies decreases
invasiveness of human trophoblasts(Xia et al, J SGI 2003)
![Page 46: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/46.jpg)
![Page 47: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/47.jpg)
-PE may be a pregnancy-induced autoimmune disease
-Key features of the disease result from
autoantibody-induced angiotensin receptor activation
![Page 48: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/48.jpg)
Endothelin-1 and Preeclampsia
• ET-1 is a potent endothelium-derived
vasoconstrictor:
– ETA receptor: vasoconstrictive response
– ETB receptor : vasodilatory response
• Elevated levels of plasma ET-1 in
preeclamptic women
![Page 49: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/49.jpg)
Endothelin-1 and Preeclampsia
• Plasma ET-1 levels ae increased in women with
a high sFlt1/PLGF ratio
• High antiangiogenic state is associated with
ET-1 activation
• Hypertension in pregnant rats can be completely
attenuated by ETA receptor antagonism
• ETB receptor activity is reduced in pregnant rats
with placental ischemia-induced hypertension
![Page 50: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/50.jpg)
Immunological Intolerance
• Normal placentation requires the
development of immune tolerance
between the fetus and the mother
• Natural killer (NK) cells play an important
role (Hanna et al, Nat Med 2006)
![Page 51: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/51.jpg)
Immunological Intolerance-
Epidemiological evidence
• Preeclampsia is more common :
– First pregnancies
– After a change in paternity
– Long inter-pregnancy interval
– Women using barrier contraceptive methods
PE = abnormal maternal immune response
to novel paternally derived fetal antigens
![Page 52: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/52.jpg)
IVF with
ejaculated
sperm
(n=1075)
ICSI with
ejaculated
sperm
(n=464)
ICSI with
surgically
obtained
sperm (n=82)
Gestational
Hypertension 11% 12% 22%
Pre-eclampsia
4% 4% 11%
Wang et al, Lancet 2002
![Page 53: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/53.jpg)
Oocyte donation and preeclampsia
![Page 54: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/54.jpg)
![Page 55: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/55.jpg)
Oocyte donation is independently associated with a higher
rate of hypertensive diseases of pregnancy
![Page 56: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/56.jpg)
Immunological Intolerance
• Decidua: Trophoblasts meet maternal NK
cells
• NK cells have an unusual phenotype:– High cytokine production
– Receptors that recognize the HLA’s on invasive
cytotrophoblasts (CT)
• The invasive CT and decidual NK cells are
closely apposed to each other
![Page 57: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/57.jpg)
Preeclampsia and Maternal Systemic
Inflammatory Response (MSIR)
• PE is associated
with a systemic
inflammatory
response
• Normal pregnancy
is also associated
with MSIR but to a
lesser extent
Preeclampsia is the extreme end of a continuum
common to all pregnancies
![Page 58: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/58.jpg)
Preeclampsia and Maternal Systemic
Inflammatory Response (MSIR)
• Placenta releases
trophoblast debris into
maternal circulation:
– Syncytiotrophoblast
microparticles
– Cytokeratin fragments
– Fetal DNA
• This debris is
proinflammatory and
increased in PE
Redman, Placenta 2003
![Page 59: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/59.jpg)
Preeclampsia and oxidative stress
• The hypoxic placenta of PE suffers
oxidative stress
• In Preeclampsia:– Enzymatic antioxidants
– Markers of high oxidative stress
Redman, Science 2005
Vitamins C and E during pregnancy has not been shown
to reduce risk of PE
Poston et al, Lancet 2006
Rumbold et al, NEJM 2006
![Page 60: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/60.jpg)
Summary: Pathogenesis of Preeclampsia
![Page 61: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/61.jpg)
Early vs late-onset Preeclampsia
• Incomplete transformation of
the spiral arteries
• Hypoperfusion of the
placenta
• IUGR
• No change/shallow
modification of the spiral
arteries
• No signs of placental
underperfusion
• Most are not IUGR
Early (< 34 wks) Late (> 34 wks)
![Page 62: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/62.jpg)
The dual etiology of late-onset
Preeclampsia
Verlohren et al., UOG 2014
![Page 63: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/63.jpg)
The dual etiology of late-onset
Preeclampsia
Verlohren et al., UOG 2014
![Page 64: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/64.jpg)
The dual etiology of late-onset
Preeclampsia
• Late-onset PE may have two different
etiologies:
– one shared with early-onset PE
resulting in SGA births
(poor trophoblast development)
–another associated with LGA births
Verlohren et al., UOG 2014
![Page 65: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/65.jpg)
The dual etiology of late-onset
Preeclampsia
• LGA form of late–onset PE:
Maternal cardiac dysfunction and inability to
meet the increased metabolic demands of an
overgrown fetoplacental unit resulting in placental
hypoxemia
• Maternal cardiac dysfunction precedes the
clinical presentation of both early and late PE
Verlohren et al., UOG 2014
![Page 66: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/66.jpg)
![Page 67: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/67.jpg)
Clinical Implications
• Biomarkers for PE:
– sFlt-1 and sEng rise 5-8 weeks before onset of
disease
– PLGF is a better 1st trimester marker
• Differential diagnosis
• Treatment:
– Restoration of normal angiogenic balance (VEGF)
– Statins: Effect on heme oxygenase-1 activity,
lowers sFlt1 production
(Cudmore et al, Circulation 2007)
![Page 68: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/68.jpg)
VEGF treatment in a rat model of
preeclampsia
Li et al, Hypertension 2007
![Page 69: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/69.jpg)
VEGF treatment in a rat model of
preeclampsia
Li et al, Hypertension 2007
control sFlt-1 sFlt-1+ VEGF
![Page 70: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/70.jpg)
![Page 71: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/71.jpg)
Pravastatin and Preeclampsia
Brownfoot et al, Hypertension 2015
![Page 72: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/72.jpg)
Thadhani al, Circulation 2011
![Page 73: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/73.jpg)
Preeclampsia, twins and sFlt-1
• In twin pregnancies with preeclampsia only one
placenta secretes elevated levels of sFlt-1
• Twins with early onset PET, IUFD of one twin
resulted in resolution of PET and reduction in
circulating sFlt-1 levels
Hladunewich et al, Nat Rev Nephrol 2006
Selective reduction in twins with
very early severe PET and IUGR
![Page 74: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/74.jpg)
Preeclampsia and Long Term Outcomes
• Women with a history of preeclampsia
risk for hypertension, stroke, coronary
artery disease and end stage renal disease
8 fold increased risk of cardiovascular death in women with a
history of preeclampsia requiring delivery prior to 37 weeks(Irgens et al, BMJ 2001)
![Page 75: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/75.jpg)
Pre-eclampsia and future
cardiovascular disease
Births 1967-
1992
GA at
birth
All
Deaths
Cardio.
death
Death from
stroke
NO PET >37 1 1 1
NO PET 16-361.56
(1.38-1.76)
2.95 (2.12-4.11)
1.91
(1.26-2.91)
PET >371.04
(0.88-1.23)
1.65
(1.01-2.7)
0.98
(0.50-1.91)
PET 16-362.71
(1.99-3.68)
8.12
(4.3-15.3)
5.08 (2.09-12.35)
Irgens et al, BMJ 2001
![Page 76: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/76.jpg)
Pre-eclampsia and future
cardiovascular disease
• 8-fold higher risk of
cardiovascular
death in women with
pre-eclampsia that
required preterm
delivery
Irgens et al, BMJ 2001
![Page 77: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/77.jpg)
Pre-eclampsia and risk of cardiovascular
disease: Meta-analysis
• After pre-eclampsia women have an
increased risk of vascular disease:
– Hypertension: 3.7 (2.7-5.05)
– Ischemic heart disease: 2.16 (1.86-2.52)
– Stroke: 1.81 (1.45-2.27)
– Overall mortality: 1.49 (1.05-2.14)
Bellamy et al, BMJ 2007
![Page 78: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/78.jpg)
Pre-eclampsia and the risk of ESRD
• Preeclampsia during the first pregnancy-RR of 4.7 (3.6-6.1) for ESRD
• Preeclampsia during 2 or 3 pregnancies was associated with a RR of 15.5 (7.8-30.8)
• Having a low birth weight infant or preterm infant increased the relative risk of ESRD
Vikse et al, NEJM 2008
![Page 79: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/79.jpg)
Smith et al, AJOG 2009
![Page 80: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/80.jpg)
What is the link between
preeclampsia and future
cardiovascular disease?
Endothelial Dysfunction
![Page 81: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/81.jpg)
Endothelial Dysfunction
![Page 82: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/82.jpg)
Chambers et al, JAMA 2001
Controls
(25)
Previous PET
(38)
P value
FMD 4.6 2.5 0.03
GTN induced 21.1 21.2 0.97
BMI 21.9 22.3 0.37
SBP 106 109 0.28
DBP 66 69 0.17
T. Cholesterol 182 182 0.98
![Page 83: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/83.jpg)
Endothelial-Dependent Vasodilatation
Control Late PE Early PE IUGR0
1
2
3
4
5
6
7
8
9
10
11F
low
-med
iate
d v
aso
dilata
tio
n (
%)
*
*
* p<0.05 versus control, † p<0.05 versus late PE
NS
†
†
Yinon et al, Circulation 2010
![Page 84: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/84.jpg)
Control
(n=16)
Late PE
(n=9)
Early PE
(n=15)
IUGR
(n=9)
FMD (%) 9.1±0.9 7.9±1.3 3.3±0.7 2.1±0.4
FMD/flow (units) 0.25±0.04 0.29±0.08 0.08±0.02 0.07±0.02
GTN-mediated
dilatation (%)18±1.1 20±1.5 16±0.9 16±1.3
Endothelial
Dysfunction, n (%)2 (13) 2 (22) 14 (93) 8 (89)
Vascular Function
*
**
**
*
* p<0.05 versus control, † p<0.05 versus late PE
†
†
††
†
†
Yinon et al, Circulation 2010
![Page 85: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/85.jpg)
sFlt-1
Control Late PE Early PE IUGR0
50
100
150
200
250
ng
/ml
sEng
Control Late PE Early PE IUGR0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
ng
/ml
VEGF
Control Late PE Early PE IUGR0
50
100
150
200
250
300
350
400
450
pg
/ml
PlGF
Control Late PE Early PE IUGR0
1
2
3
4
5
6
7
8
9
pg
/ml
Yinon et al, Circulation 2010
![Page 86: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/86.jpg)
Preeclampsia and future
cardiovascular disease
Preeclampsia
Endothelial dysfunction
Vascular disease
sEngsFlt1
Endothelial dysfunction
Vascular diseasePreeclampsia
![Page 87: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/87.jpg)
Preeclampsia and future
cardiovascular disease
Powe and Karumanchi, Circulation 2011
![Page 88: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/88.jpg)
Summary
• The antiangiogenic factors sFlt-1 and soluble endoglin produce systemic endothelial dysfunction resulting in hypertension, proteinuria and other systemic manifestations of PE
• The molecular basis for placental dysregulation of these pathogenic factors remains unknown
![Page 89: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/89.jpg)
Summary
• The renin-aldosterone-angiotensin II axis, excessive oxidative stress, syncytiotrophoblast debris, immune maladaptation and genetic susceptibility may all have roles in the pathogenesis of PE
• Middle-aged women with previous preeclampsia, especially if early and severe, have the highest risk of future cardiovascular disease and may benefit from prophylaxis
![Page 90: Latest Advances in Understanding Preeclampsia · Latest Advances in Understanding Preeclampsia ... Renin- angiotensin pathway ... •Twins with early onset PET, IUFD of one twin resulted](https://reader031.vdocuments.us/reader031/viewer/2022022805/5ca575ad88c993101e8c3d04/html5/thumbnails/90.jpg)