Scientists have uncovered a widely used medication to control epilepsy, migraines, and bipolar disorder that poses serious danger for pregnant patients, resulting to birth defects. According to the study, the anticonvulsant known as Valproic acid increases the risk of birth defects, though scientists hitherto struggled to explain exactly how this damage occurs.
The new research offers a clearer clarification by pointing to an unexpected biological process that interferes with early brain development. In a study published in PLOS Biology, researchers led by Bill Keyes at the Institute of Genetics and Molecular and Cellular Biology in France, the scientists found that valproic acid (VPA) can force critical cells in a developing embryo into a state called senescence.
In this condition, cells stop dividing and functioning as they should. While senescence is often linked to aging or the body’s response to damage, its appearance during early development can disrupt the formation of essential structures.
That disruption may help explain the wide range of problems seen in children exposed to VPA before birth. For decades, doctors have documented thousands of such cases, including neural tube defects like spina bifida, facial differences, and heart abnormalities. Research has also shown that roughly one in three exposed children later experience cognitive challenges or are diagnosed with Autism Spectrum Disorder.
To investigate what is happening at the cellular level, the team combined experiments in mice with studies using human organoids, which are small, three-dimensional models of developing tissue grown in the lab. These models allowed the researchers to observe early brain development in detail.
They found that VPA specifically affects neuroepithelial cells, a population of stem cells that normally multiply and give rise to the brain and spinal cord. Instead of continuing to grow, many of these cells entered senescence, effectively reducing the pool of cells needed to build a healthy nervous system.
The researchers traced this effect to a molecule called p19Arf, which appears to act as a trigger for the senescence response. When mice were genetically modified to lack p19Arf, some of the most striking VPArelated effects disappeared. These animals did not develop microcephaly, a condition marked by reduced head size, and they avoided certain gene activity changes linked to Autism Spectrum Disorder.
Even at that, other abnormalities still occurred, suggesting that VPA disrupts development through multiple pathways. The findings highlight a lesser-known risk factor in embryonic development. Cellular senescence has traditionally been studied in the context of aging and cancer prevention, where it can serve as a protective mechanism.
This study shows that the same process, when activated at the wrong time, may instead derail normal development. “Overall, the discovery that atypical activation of senescence in the embryo can perturb development raises the intriguing possibility that it may also contribute to defects in developmental contexts beyond those we studied here,” scientists observed.
The study’s first author, Muriel Rhinn, emphasised the broader implications: “While cellular senescence has long been associated with aging and age-related disease, we now show that aberrant induction of senescence can also contribute to developmental defects.
As valproic acid is strongly linked to cognitive defects and Autism Spectrum Disorder, this study now introduces an exciting link with senescence, supporting how additional studies are needed.”
