Most of us take medications assuming they’ll help without harm. We rarely stop to consider what happens after a pill dissolves — or how our own liver might unintentionally turn a safe drug into something dangerous, especially for our brain.
Now, scientists at Quris Technologies have uncovered evidence that some drugs become significantly more harmful to brain cells after being metabolized by the liver. The findings, published in Biomedicine & Pharmacotherapy, could change how we evaluate drug safety — and explain why some medications cause unexpected neurological side effects that animal testing often misses.
Their target was troglitazone, a diabetes drug that was pulled from the market years ago for causing liver damage.
A Smarter Way to Simulate the Human Body
For their investigation, the team built a cutting-edge laboratory system called BioAI that mimics what happens when drugs travel through the human body — what they describe as “patients-on-a-chip.” They connected miniature versions of human liver and brain tissues — called spheroids and organoids — to study how drugs processed by the liver affect the brain.
What they discovered was startling: when troglitazone was first processed by liver cells, it became dramatically more toxic to brain cells than when it was applied to the brain alone.
“We observed that troglitazone, tested at clinically relevant doses in the Liver+Brain model, caused a significantly greater reduction in cell viability compared to similar treatments in the Brain-only model,” the researchers write in their paper.
This could help explain why some dangerous side effects slip through animal testing, which doesn’t always capture how human livers uniquely transform medications into toxic byproducts.
A Closer Look at the Experimental Models
Instead of using flat petri-dish cell layers or animal models, the researchers created 3D mini-organs from human cells. Their liver spheroids included about 2,000 human cells from ten donors, replicating real human liver tissue with functioning metabolic enzymes. The brain organoids were grown from stem cells over several weeks and even produced electrical activity — a sign of working neurons.
By linking the two models together, they discovered troglitazone’s full impact. In the Liver+Brain system, the drug affected 3,941 genes in brain cells. In contrast, only 685 genes were affected when it was applied directly to the brain — nearly a seven-fold difference. Even more striking, it disrupted ten times more biological pathways, especially those involved in brain cell growth and development.
It’s Not All Bad News
Interestingly, not every drug became more dangerous after liver metabolism. Valproic acid, used to treat epilepsy and mood disorders, showed reduced toxicity after liver processing at high doses — demonstrating the complexity of how drugs interact with different organs.
The study also reinforces momentum behind the FDA Modernization Act 2.0, which supports moving away from animal testing and toward more human-relevant methods like this one.
Why This Matters for Patients and Prescribers
The study could have an immediate impact on drug testing and development. It suggests we should pay closer attention to neurological side effects — especially for drugs heavily processed by the liver. And it could help pharmaceutical companies detect brain-related risks before medications ever reach clinical trials.
Traditional safety models have often tested drugs on either isolated cells or animals, missing critical interactions that happen between organs in the human body. By simulating both liver and brain together, the BioAI model catches what others can’t.
Source : https://studyfinds.org/patients-on-a-chip-tech-exposes-drugs-quris/
