Credit: Jenny Fontaine, UIC
Researchers from the University of Illinois at Chicago College of Medicine have identified a unique chemical biomarker associated with epileptic brain tissue, according to an article published in the journal Epilepsia.
The chemical signature can be detected noninvasively and could enable physicians to precisely locate small regions of abnormal brain tissue in early-stage patients. The researchers also suggested that the biomarker could be used to pin-point localized regions of the brain needed for therapeutic removal.
“One of the biggest challenges in epilepsy is in diagnosis,” corresponding author Dr. Jeffrey Loeb said in prepared remarks. “With this new biomarker, we should be able to detect very small regions of epileptic activity – smaller than a single square centimeter – and we do it noninvasively.”
Traditionally, surgeons implant electrodes in the heads of epileptic patients in an effort to locate areas of the brain to be removed during a later surgery.
“If we can detect these areas with a high degree of precision with a brain scan, we can spare our patients additional surgery,” said Loeb. “The technology will also allow us to diagnose epilepsy much earlier. This is critical if we are to develop new treatments to prevent epilepsy from developing after a head injury, stroke, or brain tumor.”
The team used magnetic resonance spectroscopy to compare the metabolomic patterns of epileptic brain tissue and non-epileptic brain tissue removed from 9 patients.
Using a powerful imaging instrument, the researchers discovered that tissue with high levels of epileptic activity was also low in lactate and had higher levels of creatine, phosphocreatine and choline. Further analysis showed that these tissues had increased vascularization compared to the non-epileptic tissue.
When the epileptic tissue underwent genetic analysis, the team observed higher activation of genes linked to vascularization and abnormal metabolic states.
“Previous studies have used magnetic resonance spectroscopy to look at single metabolites in epileptic brain tissue, but ours is the first to use high strength magnets to look at multiple metabolites simultaneously,” Loeb said. “When combined with our genomic and histological data from these same samples, the biomarker profile was not only highly specific for epileptic brain tissues, but also revealed an abnormal metabolic and vascular state that could underlie the epileptic condition.”
The question as to why epileptic tissue boasts an abnormal metabolic profile is still unanswered and Loeb said that it needs to be addressed.
“These are areas of the brain where large populations of neurons are firing often, and this uses up a lot of energy, so it’s not surprising that we see an altered metabolic profile with a massive expansion of blood vessels,” he said.
