New
insight has been obtained regarding how alcohol during pregnancy might
affect fetal development, according to research performed at the
Medical College of Georgia Schools of Medicine and Graduate Studies,
funded by the March of Dimes.
Fetal alcohol syndrome (FAS)
according to the Centers for Disease Control and Prevention, affects 1
in 1,000 babies. Pregnant and sexually active women who are not using
effective birth control are recommended to refrain from drinking. Most
notably, babies who are the victims of this deases have classic facial
malformations, including a flat and high upper lip, small eye openings,
and a short nose. These facial clues could provide insight into the
mechanism of this process, as well as how much alcohol imposed at what
point in development might cause these changes.
Dr. Erhard
Bieberich, biochemist in the Medical College of Georgia Schools of
Medicine and Graduate Studies, has focused work on the mechanism that
cause problems for children with FAS. Strong evidence has shown that,
in just the first few weeks of fetal development, usually a period
before a woman knows that she is pregnant at all, a few glasses of wine
in an hour could increase cell death. Death of cells that might further
develop to form the face, brain, or spinal cord could lead to
developmental problems in these areas. "It's well known that when you
drink, you get a buzz. But a couple
of hours later, that initial impact, at least, is gone," states
Bieberich. "But, your fetus may have experienced
irreversible damage."
In development, there is always a set of
cells that die once they have served their purpose, and a set of cells
that move on to form other types of cells. "There is always a very
delicate balance between newly formed cells and
dying cells," says Bieberich. "It's a very active period of that
balance, because usually you develop a surplus of tissue then later
melt it back down to acquire a specific shape." The classic example of
this phenomenon is the absense of webbed fingers in newborns, while the
fetus maintains skin between the fingers for some time. "The
digits form because the inter-digital tissue dies. If it did not die,
we would have paddles instead of hands with fingers," Bieberich
says.
According
to the team, damage may result from the accelerated death
of neural crest cells, which help form various types of connective
tissue, including bone, cartilage, and parts of the cardiovascular
system. At the same time, neural tube cells form the brain and spinal
cord. This means that the visible damage shown in facial abnormalities
may be a signal that future problems could be present in learning,
memory, vision, hearing, or other areas. The cell death can result from
disruption of the metabolism of the lipids that help control the
initially undifferentiated cells, due to alcohol.
The
team compares cell loss in mice following various levels of alcohol
consumption to the usual birth and death of cells in normal
development. The focus lies in the neural crest cells, which among
their other functions form the upper part of the skull. Some of these
cells will remain in the brain, and are often controlled by the same
factors as the neural tube cells, which might lead to the cognitive and
memory problems. While this type of damage may be difficult to identify
in mice of this age, it has been shown that damage to the neural crest
gene can cause problems in both skull and brain development.
These
measurements will help women understand the true risks of alcohol
consumption during pregnancy, and help develop a method to reduce the
damage. Dr. Bierberich hopes for better education: "You have to make
people aware of the science behind the risk," he says. "We are not
saying that every pregnant woman who drinks
three or four glasses of wine in a short period will have a baby with
birth defects, but it elevates the risk."
For more information about the Medical College of Georgia and the
Bieberich Group, please see mcg/
.
Written by Anna Sophia McKenney
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