Brain tissue chip

Clusters of brain cells developed by UW-Madison scientists are shown in this microscope image.

UW-Madison photo

Three-dimensional “tissue chips,” grown from stem cells on tiny scaffolds, could become a new way to screen drugs and chemicals for toxicity, UW-Madison researchers said Monday.

Campus scientists created clusters of interacting cells that mimic the developing human brain.

The model correctly identified nine of 10 chemicals as safe or harmful, the researchers reported in the Proceedings of the National Academy of Sciences.

The model could become a cheaper and more accurate way to predict the harm of substances than single layers of cells in lab dishes or animal testing, the researchers said.

“These model neural tissues capture a lot more of the complexity than you would find in a monolayer of cells,” Michael Schwartz, an assistant scientist in biomedical engineering, said in a statement.

“They also mimic human physiology, and should be more relevant for predicting toxicity than animal models,” Schwartz said.

The project used neural stem cells developed in the lab of stem cell pioneer James Thomson.

The cells were placed on three-dimensional, synthetic environments known as “hydrogels,” designed by biomedical engineering professor William Murphy.

David Page, a biostatistics and medical informatics professor, created a computer program to detect changes in the expression of genes when the tissues are exposed to toxins.

The work, funded by the National Institutes of Health, is part of the agency’s Tissue Chip for Drug Screening program. The Environmental Protection Agency is also involved.

About 80 percent of experimental drugs fail in human clinical trials because they are unsafe or ineffective, with some 30 percent found to be toxic in people despite promising results in animal studies, according to the NIH.

Substances such as asbestos, lead, phthalates and volatile organic compounds are known to be harmful.

But of the tens of thousands of chemicals in use, “only a small fraction ... have been evaluated fully for potential human health effects,” according to theEPA.

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David Wahlberg is the health and medicine reporter for the Wisconsin State Journal.