Severed tissue from a cold-water sea cucumber can survive, heal, and even move independently for years in natural seawater, researchers recently found.
Some animals have the ability to regenerate tissues and body parts. Certain lizards can regrow their tails, for example. Some sea stars and sea cucumbers, including Psolus fabricii that live in the cold waters of the Atlantic and Arctic oceans, can regrow their severed arms or halves. However, researchers in the study showed that the discarded parts of a sea cucumber, instead of dying, can also remain viable for long periods of time.
“It’s like a lizard that loses its tail,” study co-author Rachel Sipler from Memorial University of Newfoundland in Canada, said in a statement. “We know some lizards can grow new tails; we’re talking about whether the tail can grow a new lizard.”
Sipler and her colleagues removed parts of tentacles, feet and the main body from three Psolus fabricii individuals and placed them in natural seawater in the laboratory. The tissues showed active immune responses, cell diversification, and the ability to absorb nutrients (amino acids) dissolved in the seawater. Even when the researchers stopped the experiments after three years, the tissues continued to survive.
“We haven’t grown a new, complete sea cucumber yet, but we are seeing pretty stunning growth and diversification of cells literally years after this tissue was removed,” Sipler said in the statement.
Cell lines that are “immortal” and can perpetuate indefinitely are crucial for biomedical research. However, most such “immortal” cell lines, such as the famous HeLa cells taken from a cancerous cervical tumor of Henrietta Lacks, without her consent, require meticulously sterilized conditions and enriched nutrients to survive. In contrast, the sea cucumber tissues thrived in unfiltered seawater teeming with microbes, the researchers found.
“Natural seawater is just about the most microbially diverse, least clean approach we could take experimentally,” Sipler said in the statement. “Yet, that rich environment full of bacteria and all this organic matter was actually feeding them and allowing this tissue to heal and grow.”
The study’s authors said their findings offer a “new class of experimental model” for science. Since the tissues are from an invertebrate, they are not subject to the same legal and ethical restrictions as human or vertebrate cell lines, the researchers added, potentially making high-level biological research more accessible in contexts with “limited biosafety infrastructure. ”
Beyond its medical promise, the discovery underscores the “untapped potential of ocean life,” Sipler noted. “It’s a reminder of how much is yet to be discovered in the marine environment, and how important it is to protect these resources that may hold really valuable knowledge for us.”
Banner image: Microscopy image of a tube foot severed from a Psolus fabricii sea cucumber and stained green. Denser green coloring reflects areas of more active cellular processes. Image courtesy of Sara Jobson via American Association for the Advancement of Science (AAAS).
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