By Jenna Larson
The University of Iowa has conducted a study on rats and hypertension that showed possible similarities to pregnant women with hypertension and their babies.
“Our project is to study what we think is a major cause of hypertension,” said Alan Johnson, the F. Wendell Miller distinguished professor of psychology.UI researchers have a grant to study the causes of hypertension, and they have been studying this for many years, he said.
“Hypertension is the most common of all cardiovascular diseases,” said Terry Beltz, a research specialist in the UI Psychological & Brain Sciences Department.
Hypertension is a major risk factor for heart disease and stroke, he said, and heart disease and stroke are two of the three most common causes of death in the United States.
“The study of hypertension becomes very important for the understanding of a disease that is the No. 1 cause of death in the world,” Beltz said.
For this study, researchers focused on inducing stressors to pregnant rats and examined the effects on their offspring, Johnson said.
“Different sorts of stressors will make our animals more sensitive to something that would produce a little bit of increase in blood pressure,” he said.
The researchers worked with adult animals that were sensitized to get a bigger response, Johnson said. They give animals a stressor, take the stress away, and see what their response is to something that would produce a small increase in blood pressure.
“[This] particular study is the most recent one,” he said. “And that one demonstrates that if the offspring of a mother that has had high blood pressure, when you look at those animals as adults, they show the same kind of sensitization.”
This means that something can happen very early in the baby’s lifetime that has long-term consequences when it is an adult, he said.
“That demonstration is similar to what is known in humans,” he said. “If the mothers have high blood pressure, their babies later are likely to have changes that would suggest they would have high blood pressure.”
The stress given to the rats are hormones that would be present when the animal is stressed, Johnson said.
“We also give the stressor a high-fat diet,” said Baojian Xue, a UI associate research scientist.
A high-fat diet challenges stress to the body, Xue said.
“If you want to treat hypertension, you must first know the what or the how,” Xue said. “From the clinical investigation, they show that the if mother has hypertension, that’s induced in their children, and their children [will] have a little bit higher hypertension than the control model.”
The control mother has no hypertension, he said.
“The obese mother or the mother with the high-fat diet during the pregnancy is also induced into their offspring,” Xue said.
When the study concluded, researchers were given insight to how this relates to humans.
“Maternal influences that occur during pregnancy can have long-lasting effects on the development of hypertension,” Blitz said. “Offspring can become sensitized by events that occur to the mother.”
Researchers also found that the tendency of offspring to be sensitized to hypertension in the womb because of the mother’s influence may be weakened in effect or reversed by drug therapy intervention, Blitz said.
The research doesn’t stop there, though.
Researchers are now using molecular biology to identify changes in gene expression and identifying mechanisms in which sensitization to hypertension may be altered, Blitz said.
“Our research will continue to identify the factors and pathways that lead to hypertension and look for ways to interrupt the sensitization process,” he said.
