Algae inside blood vessels could act as oxygen factories

An unconventional way to get O₂ to nerve cells might one day aid stroke patients


Light-sensitive live algae (a type of cyanobacteria called Synechocystis) injected into a tadpole moves through its blood vessels, tinging them green.

S. Özugur, H. Straka

CHICAGO — It’s a strange mash-up, but it works: Algae living inside tadpoles’ blood vessels can pump out oxygen for nearby oxygen-starved nerve cells.

Using algae as local oxygen factories in the brain might one day lead to therapies for strokes or other damage from too little oxygen, researchers from Ludwig-Maximilians University Munich said October 21 at the annual meeting of the Society for Neuroscience.

“In the beginning, it sounds really funny,” says neurobiologist Suzan Özugur. “But it works, so why not? I think it has great potential.” Even more futuristic possibilities include using algae in the veins of astronauts on long-haul space missions, says neurobiologist Hans Straka.

Straka, Özugur and their colleagues had been bubbling oxygen into severed tadpole heads to keep nerve cells active. But in talks with botanists, Straka got the idea to use algae instead. “I wouldn’t call it crazy, but unconventional, let’s say.”

The researchers injected either green algae (Chlamydomonas reinhardtii) or cyanobacteria (Synechocystis) into tadpoles’ blood vessels, creating an eerie greenish animal. Both algae species make oxygen in response to light shining through the tadpoles’ translucent bodies.

Cyanobacteria (green) in a tadpole’s blood vessels produce oxygen in response to light.S. Özugur, H. Straka

When the researchers depleted the oxygen in the liquid surrounding a disembodied tadpole head, eye nerves fell silent and stopped firing signals. But a few minutes after a flash of algae-activating light, the nerves started firing signals again, the researchers found.

So far, reactions to the work range from “Frankenstein to ‘Wow, that’s really cool,’” says Straka.

It’s not clear how long the algae can survive in the blood vessels. Nor is it clear how well animals — including people — would tolerate the extra guests.

The discovery is unlikely to be used in the clinic, says neuroscientist Kathleen Cullen of Johns Hopkins University. But it does “motivate further exploration of unconventional approaches to advance the treatments for brain hypoxia, including stroke.”

Straka’s team plans to study whether the algae can do other jobs in the brain. The algae might also be able to supply nerve cells with glucose, or even molecules that influence nerve cell behavior, he says. 

Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.

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