The formation of a specific type of brain cell during the progression of brain tumours is also linked to the development of epileptic seizures, according to a study conducted on mice and published in the leading scientific journal Nature Neuroscience. This knowledge can help scientists better understand how brain tumours cause epilepsy and potentially help them develop new approaches that can prevent or even treat the condition.“We do not understand exactly how malignant cells cause seizures, or why seizures persist after tumor surgery,” said one of the senior authors of the study, Dr Jeffrey Noebels, professor of neurology, neuroscience, and molecular and human genetics at Baylor College of Medicine in Texas, in a press release.Dr Noebels and colleagues were studying normal brain cells and in particular a type of brain cell called astrocytes. These are start-shaped cells that fulfil a broad range of roles including biochemically supporting other cell types in the brain cells, providing nutrients to the brain, and repairing the nervous tissue following injury. They are also crucial for the formation of synapses or connections between neurons.Astrocytes are often considered to be just one type of cell, but researchers identified five distinct sub-types of astrocytes based on the molecules found on their surface. They thought that the different sub-types may be responsible of fulfilling different roles in the brain.They then looked at the brain of a mouse model of glioma, or brain cancer. They saw that as the tumor grew, neighbouring cells became more excitable, and eventually the mice started to have seizures. This correlated with the emergence of one of the five sub-populations of astrocytes. Strikingly, this sub-population expressed a significant number of genes linked to epilepsy.Dr Benjamin Deneen, associate professor at Baylor explained: “[A]s the tumor evolves, different subpopulations of astrocyte-like cells develop within the tumor and execute distinct functions that are related to two important tumor characteristics, synaptic imbalance that can lead to seizures, and tumor migration that can lead to tumor invasion of other tissues”.Dr Noebels added he is excited that for the first time, it is possible to study the earliest effects of tumours on the brain before seizures even start. “These studies would be a major advance in patient care, allowing clinicians to bypass precious months spent searching for effective therapy to stop seizures. Because seizures themselves damage brain tissue, timely effective therapy is of the essence,” he concluded.Author: Dr Özge ÖzkayaWhat is an Astrocyte?The video below from the Khan Academy gives a good and accessible overview of astrocytes.
February 16th, 2017|