Climate change, California sea lions and neurosurgeons

photo: Shawn Johnson

How do these mammals ingest domoic acid?

As oceans warm, algal blooms have become more widespread, creating toxins that get ingested by sardines and anchovies, which in turn get ingested by sea lions, causing damage to the brain that results in epilepsy. Sea otters also face risk when they consume toxin-laden shellfish. These animals are taken to rescue centres and receive supportive care but tend to die or need to stay in captivity for the rest of their life. However, this month an experimental surgical procedure was tried for the first time in one affected sea lion, so far successfully.

Cronutt, the first sea lion to undergo an experimental surgical procedure to treat epilepsy

photo: Claire Simeone-UCSF

Doctors from the Department of Neurological Surgery at the University of California, San Francisco had developed a cell-based therapy for epilepsy in humans, which had shown to be highly effective in laboratory animals (mice). They had never tried it in larger vertebrates and were invited to do so in o ne of these sea lions: Cronutt, a 7-year-old sea lion, that had stranded for the first time in 2017 and was since having increasingly frequent and more severe seizures, which prevented him from even eating. Domoic acid poisoning in marine mammals causes hippocampal damage, very similar to that seen in temporal lobe epilepsy, the most common form of epilepsy in humans. It was certainly worth a try.

The procedure was carried out on October 6, and it went smoothly. Since then, Cronutt has been sleeping and eating well, recovering from surgery, although it is still too early to assess the success of the treatment. If it works, it opens a myriad of possibilities, both to really help stranded sea mammals affected by domoic acid poisoning, and to further and improve the research for treatment of epilepsy in humans.

Read here the whole story.