The impact of obesity on the maternal metabolic adaptation to pregnancy

Dilys J FreemanInstitute for Cardiovascular and Medical SciencesUniversity of Glasgow

Dilys J Freeman

Disclosed no conflict of interest

Presenter Disclosure Information

• Healthy pregnancy

• Obese pregancy

• Complicated pregnancy (preeclampsia)

HealthyH

Healthy Pregnancy

Gestational hormonal changes

Paulev and Zubieta-Calleja, Textbook in Medical Physiology and Pathophysiology, 2nd Ed

Taggart (1967) Br J Nutr 21;439

Fat acquisition during pregnancy

Adipose tissue adaptation to pregnancy

First trimester gain in insulin sensitivity

Gain in fat

Mid-trimester loss of insulinsensitivity

Increased adipose

turnover

Fetal growth

Non-pregnant Mid gestation Term

Huda et al Clinical Lipidology 2009

NEFA

Plasma NEFA flux vs concentration

TG NEFA

AdiposeTissue

Plasma compartment

Liver/Placenta

Utilisation

TG NEFA Utilisation

Non-pregnant

Pregnant

SAT physiological storage depot in pregnancy

↑ NEFA release

pregnancy hormones

insulin resistance+

VLDL

Adipose tissue depots – relative contribution

Visceral(VAT)

Subcutaneous

Upper body(USAT)

Lower body(LSAT) total lipolysis net lipolysis

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

USAT

VAT

mm

ol/

L/u

g D

NA

gly

cero

l o

r N

EF

A

Huda et al submitted

P=0.005*

P=0.026*

USAT is more lipolytic than VAT in the third trimester of pregnancy

Ex-vivo basal adipocyte lipolysis experiments

Effect on lipolysis: + +- + + + -/?-+/?

Forrest et al unpublished

SAT and VAT lipolysis regulated differently

Receptor profile suggests: - in VAT pregnancy hormones reduce lipolysis- in SAT pregnancy hormones promote lipolysis and adrenergic-driven lipolysis is reduced

SAT as a reservoir of fatty acids in health

• Based on the functionality and size of the SAT depot, we would suggest that in healthy pregnancy plasma NEFA are derived from this depot

• In the non-pregnant (Jensen et al JCEM 2008), USAT is estimated to be the source of 60% of circulating NEFA, LSAT 15-20% and VAT 6-17%

• SAT provides a “safer” depot for gestationally-acquired fat as VAT releases NEFA into the portal circulation and hence directly to the liver

SAT vs VAT lipolytic and lipogenic function

insulin sensitivity0

10

20

30

40

50

60

70

80

90

100

USAT

VAT

per

cen

t in

hib

itio

n o

f IP

A s

tim

ula

ted

li

po

lysi

s %

P=0.046*

Ex-vivo basal adipocyte lipolysis experiments

Huda et al submitted

USAT and UVAT mRNA expressionInsulin sensitivity assessed as insulin suppression of isopreterenol-stimulated lipolysis

Exp

ressio

n r

ela

tive t

o P

PIA

(%

)

0

5

10

15

Subcutaneous

Visceral*

INSR

Exp

ressio

n r

ela

tive t

o P

PIA

(%

)0

50

100

150

200

***

LPL

Subcutaneous

Visceral

LPL is a lipogenic enzyme

Insulin receptor

Lipoprotein lipase

Improved vascular function is a keyadaptation to pregnancy

Endothelium-dependent microvascular function

Stewart et al JCEM 2007

P<0.001

Required for placental formation and perfusion

Hypertriglyceridaemia: the need for vascular protection

Rasmussen et al Scan J Clin Lab Inv 2009

Data compiled from different overlapping longitudinal studies

* Significantly different from baseline

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

0 5 10 15 20 25 30 35 40 45 50 55 60 65

weeks (gestation)

mm

ol/

L T

rig

lyce

rid

e

Triglyceride

** *

*

*

Mackay et al unpublished

Late gestational lipid metabolism

Huda et al Clinical Lipidology 2009

High Density Lipoprotein (HDL)

Reverse cholesterol transport

Delivery of cholesterol to steroidogenic tissues

Vascular protection:-

• Prevents LDL oxidation• Inhibits ROS generation and

inflammatory signalling• Inhibits apoptosis & necrosis• Promotes cell survival by

carrying protective agents such as S-1-P

1.00

1.20

1.40

1.60

1.80

2.00

2.20

0 5 10 15 20 25 30 35 40 45 50 55 60 65

weeks (gestation)

mm

ol/L

HD

L

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

mm

ol/L

tri

gly

ce

rid

e

HDL Triglyceride

HDL increases over gestation

Delivery30%

increase

Placental circulationestablished

Data compiled from different overlapping longitudinal studies

n=225

Mackay et al unpublished

HDL and endothelium-dependent vascular function in pregnancy

1.000.750.500.250.00-0.25-0.50

10000

5000

0

-5000

-10000

-15000

-20000

Gestational change in HDL (mmol/ L)

Gest

ational c

hange in

EDM

VF

(PU M

Ohm

.min

)

r=0.42, p=0.013, r2=18% independent of maternal age, parity and smoking status

Gestational change = Post natal HDL - T3 HDL

No significant association with endothelium-independent microvascular function

n=34 Mackay et al unpublished

Concentration vs function

But.............

HDL concentration tells us nothing about HDL function

10.07.55.02.50.0-2.5-5.0

2500

2000

1500

1000

500

0

-500

-1000

incremental AUC HDL (mmol/ L*weeks)

incr

em

enta

l AU

C p

ara

oxonase

(ug/m

L*w

eeks)

r=0.47, p=0.043, r2=17%

Paraoxonase – PON-1

• Responsible for most of the anti-oxidative effects of HDL

• Protects against atherogenesis• Synthesised in the liver, carried by

HDL• Hydrolytic activity decreases lipid

peroxides• Mixed data on the effect of gestation

on PON-1 activity

n=19

Mackay et al unpublished

Maternal Obesity

Maternal obesity and hormones

Meyer et al JCEM 2013

Huda et al unpublished

P=0.038

Progesterone Placental lactogen0

2

4

6

8

10

12

14

healthy overweight obese

Pro

ges

tero

ne

or

pla

cen

tal

lact

og

en

(ug

/mL

)

Jarvie et al unpublished

Fat acquisition during pregnancyin lean and obese women

0

5

10

15

20

25

30

35

40

45

50

15 25 35

gestation (weeks)

fat

mas

s (k

g)

lean

obeseLean 4.3 kgObese 4.0 kg

Lean and obese women accumulate similar mass of fat

See Ellie’s poster No. 15 for more detail on the contributory elements of energy metabolism to this fat gain in lean and obese women

Maternal BMI and triglyceride response to pregnancy

0

0.5

1

1.5

2

2.5

3

3.5

15 20 25 30 35 40 45

BMI (kg/m2)

Tri

gly

ceri

de

(mm

ol/

L)

Trimester 1 Trimester 2 Trimester 3 Postnatal

154%66%

Meyer et al JCEM 2013

Actually a larger TG response in healthy weight than obese women

Healthy weight women are more metabolically flexible

baseline

gestation(weeks)

metabolic marker(concentration)

Location of fat and adaptation to pregnancy

Metabolic marker

Fat depot

Pearson correlationcoefficientunivariate

Contribution to variance

multivariate

P value Adjusted†

contributionto variancemultivariate

Adjusted P value

VLDL-1 UVAT -0.23 19.3% 0.005 13.3% 0.026

USAT 0.15 14.4% 0.013 12.9% 0.028

VLDL-2 UVAT -0.32 13.1% 0.027 5.3% 0.075

Incremental area under the curve

† adjusted for maternal age, parity, smoking status, deprivation category and gestations at sampling

Jarvie et al unpublished

Metabolic flexibility in pregnancy

High UVAT/ USAT

Low UVAT/USAT

Sattar & Freeman Chpt 5; 45-55Maternal Obesity Ed Gillman & Poston

Obese pregnancy & microvascular function

Predictors of endothelium-dependent

microvascular function in obese

pregnancy:

• obesity, 19.3%, p<0.001• gestation, 11.2% p<0.001• IL-6, 4.0%, p=0.002• IL-10, 2.4%. P=0.018

Endothelium dependent

Endothelium independent

Stewart et al JCEM 2007

P<0.001

P=0.021

Baseline metabolic markers - independent association with fat depot

Metabolic marker

Fat depot

Pearson correlationcoefficientunivariate

Contribution to variance

multivariate

P value Adjusted†

contributionto variancemultivariate

Adjusted P value

Leptin USATUVAT

0.680.65

9.1%6.3%

0.0020.009

8.9%4.0%

0.0070.039

Adiponectin UVAT -0.46 8.4% 0.020 9.4% 0.018

IL-6 USAT 0.57 8.4% 0.009 8.2% 0.013

CRP USAT 0.55 11.2% 0.004 9.7% 0.007

End DepMicrovascularFunction

UVAT -0.43 7.7% 0.025 5.7% 0.062

† adjusted for maternal age, parity, smoking status, deprivation category and baseline gestation

Baseline

Jarvie et al unpublished

Hypertrophy vs hyperplasia of adipocytes

Increased flux of non-esterified fatty acids (NEFA)

Central obesityNon-obese or lower body obesity

macrophage infiltrationand adipokine secretion

lipolysis

Hypertrophy Hyperplasia

Ex-vivo maternal USAT adipocyte CRP secretion

USAT and UVAT adipocytes were prepared by collagen digestion from fat biopsies at C-section.

CRP secretion from these adipocytes was measured using a suspension array (Bioplex).

USAT, but not UVAT, adipocyte CRP secretion correlated with third trimester maternal plasma CRP levels.

3.02.52.01.51.0

1.2

1.0

0.8

0.6

0.4

0.2

0.0

log CRP basal release (SAT)

log m

ate

rnal C

RP (

pla

sma)

r=0.66

r=0.66, p=0.005

Huda et al unpublished

Pregnancy exposure to metabolic marker - independent association with

fat depot

Metabolic marker

Fat depot

Pearson correlationcoefficientunivariate

Contribution to variance

multivariate

P value Adjusted†

contributionto variancemultivariate

Adjusted P value

CRP USAT 0.47 7.6% 0.047 8.3% 0.037

End DepMicrovascularFunction

USAT -0.59 12.1% 0.007 13.3% 0.009

Total area under the curve

† adjusted for maternal age, parity, smoking status, deprivation category and gestations at sampling

Jarvie et al unpublished

Maternal BMI and HDL concentration

1

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2

15 20 25 30 35 40 45

BMI (kg/m2)

HD

L c

ho

lest

ero

l (m

mo

l/L

)

Trimester 1 Trimester 2 Trimester 3 Post natal

20%

12%

n=98

Mackay et al unpublished

Pregnancy Complications

O’Brien et al (2003) Epidemiology

1 BMI unit 0.5% PE prevalence

Torloni et al (2009) Obesity Rev

1 BMI unit 0.9% GDM prevalence

Maternal BMI and incidence of GDM and PE

Obesity and the development of type 2 diabetes in the non-pregnant

Excess dietary fat

NEFA spillover

pancreatic beta cell

muscle

liver

Hypertrophic obesity

Ectopic lipid accumulation

Adipocyte function in PE

FCISIcontrol vs. PE

FCIS

I (%

)

-50

0

50

100

150

Control ControlPE PE

SAT

VAT

0.04

FCISIControl vs. PE

Fat cell insulin sensitivity index (FCISI) – the ability of insulin to suppress beta adrenergic stimulated lipolysis

Huda et al unpublished

In PE, SAT adipocytes as insulin resistant as VAT

Plasma NEFA flux vs concentration

TG NEFA

AdiposeTissue

Plasma compartment

Liver/Placenta

Utilisation

TG NEFA Utilisation

TG NEFA Utilisation

lipolysis ↓ utilisation

Non-pregnant

Pregnant

Pregnant - pathological

Ectopic fat is the problem not obesity

Stefan et al Arch Intern Med 2008

Plasma markers of liver fat in the non-pregnant

• Fatty liver is a powerful determinant of plasma small dense LDL (Sugino et al J Atheroscler Thromb 2011;18:1-7)

• Fatty liver in type 2 diabetes is associated with increased small dense LDL (Toledo et al Diabetes Care 2006;29:1845-50)

• In NAFLD there is depletion of LC PUFA possibly via reduced 5- and 6-desaturase activities (Videla et al, Free Radic Biol Med 2004)

Increased small dense LDL in obese pregnancy

In the third trimester, the proportion of small, dense LDL was 2-fold higher in obese women than normal weight women and 35% of obese, 14% of overweight, and none of the normal weight women displayed an atherogenic LDL subfraction phenotype.

Trimester 3

0%

20%

40%

60%

80%

100%

Healthy Obese

% LDL-III

% LDL-II

% LDL-I

P=0.004

P=0.005

Meyer et al JCEM 2013

Evidence for ectopic fat in PE - decreased LC PUFA synthesis

■ Maternal □ Cord

Maternal and cord blood LC PUFA concentrations

Subcutaneous adipose tissueenzyme mRNA expression

FADS1 - 5 desaturaseFADS2 - 5 desaturaseSCD - stearoyl coA desaturaseELOVL2- very long chain FA elongaseELOVL6 – long chain FA elongase

MacKay et al Hypertension 2012

Subcutaneous adipose tissue

0

2

4

6

8

10

12

14

FADS1 FADS2 SCD ELOVL2 ELOVL6mR

NA

exp

ress

ion

(sq

rt t

arg

et/P

PIA

)

Control

PE

IUGR

P=0.020

*P=0.001

*P=0.043

#

Excess dietary fat

pancreas placenta?liver

Hypertrophic obesity

Ectopic lipid accumulation

Ectopic sites of fat storage in pregnancy

NEFA

spillover

visceraladipose tissue

bloodvessel

Placental lipidomic analysis

Figure 1. A. Total placental lipid, ** P<0.05 vs control and IUGR and B. Placental phosphatidyl choline (PC) arachidonic acid (AA) content * P<0.05 vs control, mean (SEM), in healthy (n=70), preeclampsia (n=19) and IUGR (n=12) pregnancy.

Eather, Freeman, Brown, Mitchell, Meyer unpublished

University of Wollongong Placental lipids were extracted and analysed on a hybrid triple quadrupole, linear ion trap mass spectrometer (AB Sciex QTRAP 5500) equipped with an automated, chip-based nanospray source (Advion Triersa Nanomate).

PE placenta has higher total lipid content and arachidonic acid content than controls

Implications for placental function –inflammation?

Figure 1: Placental samples showing CD68 positive macrophages (brown) under magnification x 40. (A) BMI ≥35 kg/m2, (B) BMI <35 kg/m2. Scale bar (bottom right) represents 50m. Figure 1C: Boxplot comparing log macrophage counts in the BMI<35kg/m2 group compared to the BMI≥35kg/m2 group. Represented as median, inter-quartile range, maximum and minimum of log transformed data.

A

B

>or=35<35

3.5

3.0

2.5

2.0

1.5

1.0

0.5

BMI (kg/ m2 )Lo

g m

acr

ophage d

ensity

(co

unts

per field

)

p=0.004

Huda et al unpublished

Pavan et al Endocrin 2004

……probably via LXR activation

OxLDL inhibits trophoblast invasion…..

Implications for placental function –trophoblast function?

Decreased antioxidant defences in preeclampsia

0

50

100

150

200

250

300

Control PE IUGR

Par

aoxo

nase

act

ivity

(ug/

mL)

P=0.012

n=125 n=57 n=16

Lower paraoxonase activity in preeclampsia

Dysfunctional HDL?

Mackay et al unpublished

Maternal obesity - a perfect storm?

Maternal obesitylipolysis ’safe’ storage of TGinsulin resistance

oxidative stressoxidised lipids

ectopic fat accumulationlipotoxicity

placenta

NEFA

maternal endothelial /vascular

stress

trophoblast invasion? uteroplacental

insufficiency

altered development, fat metabolism & transport

& inflammation

offspring obesityadverse maternal

outcomeJarvie et al Clin Sci 2010

AcknowledgementsICAMS

Ellie Jarvie

Rachel Forrest

Ann Brown

Fiona Jordan

Vanessa Mackay (née Rodie)

Frances Stewart

Christopher Onyiaodike

Naveed Sattar

Muriel Caslake

Glasgow Collaborators

Bill Ferrell

Shahzya Huda

Scott Nelson

University of Manchester

Mike Mackness

Project students

Jack Bray

Sam Eather

Louise McKenna

Iain Martin

Nicole Patterson

University of WollongongBarbara MeyerTodd MitchellSimon Brown

University of SurreyBruce Griffin

University of UmeaGunilla Olivecrona