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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 30, No 4, July/August 2019
AFRICA
213
condition may lead to the development of certain pathologies in
both the mother and foetus.
32
Although the placenta was thought to be impermeable to
lipoproteins, Frantz
et al.
33
showed that this may not be the case,
and results from our study also suggest cholesterol possibly
crossed the placenta into the foetus. This is consistent with
earlier observations that foetal cholesterol levels showed an
inverse correlation with maternal cholesterol level during the
first six months of life.
16
Increased cholesterol levels in offspring
of normocholesterolaemic mothers did not, however, result in
atherosclerotic lesion formation in this study.
Maternal hypercholesterolaemia in rabbits led to the
formation of atherosclerotic lesions in the aortic arch and
descending thoracic aorta of offspring, as shown by increased
intima–media thickness and the presence of lesions in sections
of the aorta. Increased intima–media thickness of arteries, a
consequence of pathological vascular remodelling, is associated
with several risk factors for atherosclerosis, including age,
systolic blood pressure, diabetes, LDL cholesterol, smoking and
familial hypercholesterolaemia in humans.
34
The intima–media
thickness is also increased in hypercholesterolaemic patients
compared to controls,
35
and has become a convenient marker for
atherosclerosis.
36
Oxidation of LDL cholesterol is key in the initiation of
atherosclerosis
7
and may also trigger vascular remodelling
by enhancing smooth muscle cell proliferation and collagen
deposition, leading to increased intima–media thickness.
Increased deposition of elastic and collagen fibres was observed
in the present study, shown by VVG-stained sections of aortic
arch and thoracic aorta, suggesting increased atherogenesis, as
shown previously.
37
Moreover, maternal hypercholesterolaemia
has already been shown to increase the presence of collagen
fibres in the intima–media of coronary arteries.
31
The association
of cocoa intake with a smaller number of aortic sections with
atherosclerotic lesions, as well as reduced collagen and elastic
fibre staining in the rabbits may be explained by inhibition of
LDL oxidation
20,22
and reduction in oxidative stress through high
antioxidant
23,26
and anti-inflammatory
24
activity.
Maternal hypercholesterolaemia may also trigger the
formation of fatty streaks and atherosclerosis in offspring by
enhancing endothelial dysfunction,
32
a key event in the initiation
and progression of atherosclerosis. It is known that flavanol-
Aortic arch
Thoracic aorta
Abdominal aorta
NC
HC
HCC
Fig. 6.
Histomicrographs of Verhoeff–Van Gieson-stained sections of the arch, thoracic and abdominal segments of the aorta from
offspring of NC, HC and HCC rabbits. Elastic fibres are stained blue-black or black and collagen fibres are stained red or pink.