The chemical pathways by which alcohol causes neurological cell death in chick embryos overlap with the pathways that give alcohol its addictive properties, a University of Wisconsin-Madison fetal alcohol researcher announced in a study published this month in the journal Alcoholism: Clinical and Experimental Research.
“We found that calcium released by alcohol has an immediate and devastating effect on certain neurological cells,” says Susan Smith, a professor of nutritional sciences in the UW-Madison’s College of Agricultural and Life Sciences. “In this study we show clearly the source and the target of the calcium, and we also show that the pathways of cell death overlap with some of the pathways that give the addictive and rewarding properties of alcohol.”
The finding that alcohol acts through similar pathways to both kill embryonic cells and affect adult brain function suggests that researchers may be able to predict how alcohol will affect neurons, Smith says. And she adds, “The shared signaling is consistent with concerns that prenatal alcohol exposure could increase a person”s desire for alcohol rewards later in life.”
Smith and researchers Ana Garic-Stankovic and Marcos Hernandez injected alcohol into chicken eggs that contained developing embryos, along with chemical compounds that target and highlight the signals of neurons in the brain. The researchers then examined the embryos under a powerful microscope and observed second by second how the calcium released by the alcohol affected developing neurological tissue.
“We immediately saw a flood of calcium, and within the first second we saw that certain brain cells were affected, and died shortly afterward-and those cells are not regenerated. It only took one dose of about .3 percent alcohol, which by human standards is high but achievable, especially for alcoholics,” explains Garic-Stankovic.
What’s more, Garic-Stankovic says, the calcium appears to affect only very specific regions of the brain in early development. “One long-term goal of the project is to determine why certain cells are so susceptible to damage from alcohol.”
Fetal alcohol syndrome, which can occur when a fetus is exposed to high levels of alcohol during pregnancy, is often diagnosed by the presence of facial deformities as well as neurobehavioral problems. More common than Down syndrome or cerebral palsy, it is the leading cause of mental retardation in much of the world. According to conservative estimates, it occurs about two or three times in every thousand live births in the United States, says Smith.
However, recent research suggests that repeated exposure to lower amounts of alcohol during development can cause a range of problems, including impairments in learning, judgment and attention that may not be apparent until the child is four or five years old, say Smith. “The broader exposure may be applicable to as many as one in every one hundred live births,” she says. “It’s a lot more common than we talk about.”
The cost of treating the social issues surrounding fetal alcohol exposure is enormous, says Smith, and the issue of women drinking while pregnant is an extremely sensitive one to address. In addition, women may drink before they realize they are pregnant–this is especially a concern when it comes to college students who binge drink, she says.
“This is not just an issue for alcoholic mothers,” Smith says, noting that a recent survey indicated that 41 percent of women in Wisconsin consume alcohol regularly. “We do not know if there is a safe level of alcohol to consume during a pregnancy. Women need to be informed so they can make good decisions when they learn they are pregnant. Alcoholic women especially need better access to interventions that also address their family situations.”
Smith’s work is supported by the National Institute on Alcohol Abuse and Alcoholism, and the state of Wisconsin.