p1-41 developmental programming of cardiovascular dysfunction by maternal obesity
TRANSCRIPT
S94 Posters
P1-40 The influence of birth weight on blood pressure and
body composition of Brazilian children from 5 to 8 years
of age
J.A. Pereira, P.H.C. Rondo *, J.M.P. Souza, J.O. Lemos, J.F. Moura,
R.S.C. Dias. Department of Nutrition, School of Public Health,
University of Sao Paulo. Avenida Dr. Arnaldo 715, CEP- 01246 904,
Sao Paulo, SP, Brazil
E-mail: [email protected]
Aim: To assess the relationship between birth weight (BW), blood
pressure and body composition of children.
Study design: Prospective cohort study.
Subjects: 472 Brazilian children from 5 to 8 years of age.
Outcome measures: Systolic and diastolic blood pressure,
mid-upper arm circumference, waist circumference, skinfold
thickness.
Results: Linear regression models were applied to investigate the
relationship between independent (BW and birth length BL) and
dependent (weight, height, BMI, waist circumference WC, fat
mid-upper arm area FMUAA, systolic blood pressure SBP and
diastolic blood pressure DBP, cholesterol, triglycerides) variables.
The prevalence of children with a SBP � the 95 centile was
high (35.16%); 5.09% of the children had a DBP � the 95 centile.
BW was positively correlated with FMUAA and BMI (p < 0.001). In
the linear regression model, adjusted for BMI, it was noticed a
significant inverse relationship between BW and SBP. There were
no statistically significant associations between BL and systolic and
diastolic blood pressures.
Conclusions: The inverse relationship between BW with actual
SBP and the high prevalence of overweight, justify the control of
the nutritional status of children since the fetal period and the
monitoring of BP in the pediatric routine.
P1-41 Developmental programming of cardiovascular
dysfunction by maternal obesity
A.M. Samuelsson*, A.I. Awopetu, P.A. Matthews, P.D. Taylor,
L. Poston. Division of Reproduction and Endocrinology, King’s
College London, United Kingdom
E-mail: [email protected]
Aims: To study the effects of maternal diet-induced obesity on
offspring cardiovascular function in a murine model.
Study design: Female C57BL/6J mice were fed either a control diet
(4% corn oil) or a highly palatable, hypercalorific diet (20% fat,
38% sugar) for six weeks and throughout pregnancy and lactation.
All offspring were weaned onto control diet and cardiovascular
function was assessed at three and six months of age by remote
radio-telemetry. Surgical implantation of a radio-telemetry probe
via the left carotid artery was performed in anesthetized mice using
medetomidine and ketamine, and reversed by atipamezole.
Outcome measures: Systolic and diastolic blood pressure and heart
rate were recorded in conscious freely moving mice over a 24 hour
period, one week after surgery.
Results: Both male and female offspring of obese dams (OO)
showed a significant increase in systolic blood pressure and
heart rate compared to controls (OC) at three months (P< 0.05),
which was further augmented at six months (average night-
time systolic blood pressure [mmHg] at six months, mean±SEM,
male OO, 134±1.4 vs. OC, 124.4±2.1, n = 8, P < 0.05; female
OO, 136.8±2.4 vs OC, 121.8±4.2, n = 8, P < 0.01; average night-
heart rate [bpm] at six months, male OO, 636.6±15.8 vs
OC, 549.5±21.6, n = 8, P < 0.01; female OO, 632.7±21.1 vs
OC, 554.5±24.8, n = 8, P < 0.01).
Conclusions: Maternal diet-induced obesity programmes systolic
hypertension and increased heart rate in male and female offspring
from early adulthood contributing to increased risk of metabolic
syndrome and cardiovascular disease in this model.
Funded by the British Heart Foundation and EARNEST.
P1-42 Placental restriction leads to an upregulation of the
angiotensin II receptors AT1R and AT2R mRNA in the
aorta of the fetal sheep in late gestation
A.D. Snell1,2 *, I.C. McMillen1, S. Gentili1, J.L. Morrison1. 1Early
Origins of Adult Health Research Group, Sansom Institute,
University of South Australia, Adelaide, South Australia 5005,
Australia, 2School of Molecular and Biomedical Science, Discipline
of Physiology, The University of Adelaide, 5005, Australia
E-mail: [email protected]
Aims: Chronic hypoxia, which can be induced by placental
restriction (PR), leads to a redistribution of blood flow from
the periphery to vital organs like the brain. Whilst studies have
implicated the actions of Angiotensin II (Ang II), in the regulation
of peripheral vasoconstriction, it is unknown whether there is
an upregulation of the Angiotensin Type 1 receptor (AT1R) which
mediates the vasoconstrictor actions of Ang II. Therefore the aim
of the current study was to determine the impact of PR on the
expression of AT1R and AT2R mRNA in the aorta of the sheep fetus
in late gestation.
Study design: Carunclectomy was performed in 6 non-pregnant
ewes to induce PR. Vascular catheters were inserted in 6 PR and
4 control (C) fetuses at 103 117d. Post mortem was performed
at 139 141d and gene expression was measured using normalized
Real-time PCR.
Outcome measures: Fetal Weight, mean gestational PO2 and
relative expression of AT1R and AT2R.
Results: Fetal weight (C, 4.3±0.3 kg; PR, 2.5±0.3 kg) and
mean gestational PO2 (C, 20.6±1.9; PR, 2.7±0.8 mmHg) were
significantly lower in PR fetuses (P< 0.01). In the aorta, the relative
expression of AT1R (C, 0.03±0.003; PR, 0.05±0.005) and AT2R
(C, 0.006±0.002; PR, 0.016±0.002) were each higher in PR fetuses
(P< 0.05).
Conclusions: Previous studies have shown that the PR fetus is more
dependent on Ang II for blood pressure maintenance. Increased
expression of AT1R and AT2R in the aorta may be an indicator
of global upregulation of the Ang II receptors under low oxygen
conditions.
P1-43 The influence of birthweight on cardiomyocyte number
in postnatal lambs
V. Stacy1 *, M. Probyn2, R. De Matteo1, N. Wreford1, R. Harding1,
M.J. Black1. 1Department of Anatomy and Cell Biology, Monash
University, VIC 3800, Australia, 2School of Biomedical Sciences,
University of Queensland, Brisbane, QLD, Australia
E-mail: [email protected]
Aims: Little is known about the effects of IUGR on the development
of cardiomyocytes. As cardiomyocytes cease proliferating soon
after birth, the ultimate number is determined during fetal and
early postnatal life. Twinning provides a natural model of moderate
IUGR. Our aim was to determine whether IUGR due to twinning
alters cardiac muscle development in sheep.
Methods: Hearts were collected at necropsy from either singleton
(n = 5) or twin (n = 5) lambs at 9 weeks of age. At this age,
cardiomyocytes in sheep are terminally differentiated. The walls
of the left and right ventricles were systematically sampled. The
number of cardiomyocytes was estimated using an unbiased optical
disector/fractionator stereological technique.
Results: At birth, twins were 17% lighter than singletons ( p = 0.007)
and remained lighter to 9 weeks. At 9 weeks the hearts of
twins were 28% lighter than those of singletons ( p < 0.001) but
were not different when adjusted for body weight. At 9 weeks,
although there was no significant difference between twins and
singletons in total ventricular cardiomyocyte number (i.e. in left
ventricle, septum and right ventricle), there was a significant
positive relationship between the number of cardiomyocytes and
body weight at birth ( p = 0.002) and at 9 weeks ( p = 0.002).
Conclusions: Our study shows that low birthweight leads to smaller
hearts with reduced numbers of ventricular cardiomyocytes. A
reduced number of cardiomyocytes could lead to compromised