In vitro presents health risks

Temple’s Dr. Carmen Sapienza recently led a study that found embryos fertilized via in vitro fertilization were predisposed to certain health risks, including colon cancer and low birth weight.

It has been almost 10 years since the human genome was sequenced, and scientists have been struggling to put the results of this project to practical use in predicting diseases.

The project, which aimed to identify all of the 20,000 to 25,000 genes in human DNA, has been most helpful in identifying rare diseases, as well as more common ones like diabetes, heart conditions and common cancers.

A recent study headed by Temple’s Dr. Carmen Sapienza looked at in vitro fertilization, the process by which a child is conceived outside of the womb, allowing otherwise infertile mothers to give birth, in an effort to examine whether it was the environment, the situations surrounding the child’s birth or the child’s genes that put it at greater risk for common diseases.

“Our hypothesis was that the way the environment interacts with your genes is by modification of the genome,” Sapienza said. “Here was a clear case where we knew the environment was different.”

More than 31 years ago, the first successful in vitro fertilization took place in the United Kingdom. Since then, nearly 4 million children have been conceived in vitro. Findings reveal children born through this process are at a slightly greater risk relative to the general population for some undesirable traits, such as low birth weight, which can lead to obesity and diabetes later in life.

Through a process known as “DNA Methylation,” Sapienza and other researchers, partnered with the University of Pennsylvania’s fertility center, compared a sample of children conceived in vitro with another sample born in vivo, or in the womb.

Sapienza and her team found that while being conceived in vitro does not affect what genes an individual has, it can affect which genes are turned on in that person. Since only 5 percent to 6 percent of these children were significantly out of the norm in terms of genes, it cannot be attributed definitely yet to in vitro fertilization and may be the result of the parents’ genes, so these children are for the most part completely normal.

“Most of these kids are fine,” Sapienza said. “You have to search hard to find differences between the two groups.”

However, if this experiment is repeated with identical results, the impact the environment plays in increasing risk for disease can eventually be determined. Once this is fully understood, individuals who are at risk for these conditions can be informed and can have the opportunity to alter their lifestyles to avoid health issues later in life.
“We’re trying to figure out some way to add value to the genetic information that people can have for risks for particular kinds of diseases,” Sapienza said. “Before you can do that, you need to figure out how much interaction there is between genes and environment.”

In the experiment, the researchers found the sample of the group may be at a higher risk for colon cancer. If this finding is confirmed by further experiments then the population that was conceived in vitro can be informed, and can take simple precautionary actions which can prevent certain medical emergencies later in life.

“There’s no excuse for anyone to die of colon cancer, and what you should do is instead of waiting until you’re 50, you should have your first colonoscopy at 30,” Sapienza said.

If these experiments are repeated with larger sample sizes, it can eventually be determined which abnormalities are caused by the parents and which are caused by the environment. Eventually, researchers could correct the problems causing these genes to turn on or off and create an ideal environment where in vitro fertilization would be identical in its results to in vivo fertilizations.

The study, published in Human Molecular Genetics and Epigenetics paves the way for future research which may help determine the impact that environment has on genetics as well as helping to improve in vitro fertilization. Further research may lead to an increase in the availability of information about personal risk of disease for the general population, and will allow people to alter their lifestyles accordingly.

“If you give them real information, they can make their own decisions,” Sapienza said.

Abe Rosenthal can be reached at abraham.rosenthal@temple.edu.