Chemotherapy Drug 5-FU and Chemo Brain
A scientific study was published last week that showed a specific chemotherapy drug called 5-fluorouracil (5-FU) caused nerve damage in mice, you can read the full article here. What is interesting about this study is that it might help to explain something known as “chemo brain”.
Roughly a third of people having chemo develop memory problems, (e.g. trouble remembering where you left your purse, or finding the right word to describe something), some people also find it harder to do two things at once (eg write a list and talk on the phone at the same time) other people find it harder to learn new things. The technical name for these sort of problems is “cognitive defects”. Some studies have put these problems down to the stress of treatment but this study suggests that there might be a biological explanation.
So what does 5-FU do to nerve cells? Well, it looks like the drug damages a certain sort of nerve cell (more than any other) called the oligodendrocytes (All ig o den dro sights). These cells normally make the fatty myelin sheath that surrounds nerve cells. This surrounding sheath is a bit like the plastic insulation wrapped round your electricity cables, it allows your nerve cells to work faster. Cells treated with 5-FU had much less of this myelin insulation layer.
A picture of a myelin sheath (in orange) around a nerve fibre (in brown)
What does this mean if you’ve had (or are having) treatment with 5-FU? 5-FU kills cancer cells, the bottom line is that it is better to kill the cancer cells than live without “chemo brain”. If you do get chemo brain, know that you aren’t “losing your mind” it is just another side effect of the treatment that will usually get better over time and it’s caused by damage to your oligodendrocytes. More lab work will be done to work out why this happens and the more we know about that the more likely we are to develop treatments that can prevent or avoid this happening in the future.
What does that word mean?
Cognitive - Concious thinking for example, learning, remembering, imagining and understanding.
Oligo - means just a few, so that means oligodendrocytes aren’t the most numerous cells in the central nervous system.
Dendro - like a tree, a description of the cells shape under a microscope
cyte - (pronunced sight) cell