Researchers have documented for the first time the prolonged viability of a body fragment outside of sterile laboratory settings, challenging established notions about tissue immortality.
From the reanimated corpse of Frankenstein’s monster to the severed hand known as “Thing” in “The Addams Family,” living tissue detached from its original form is a staple of science fiction. This trope of life persisting after losing its initial wholeness appears to have a real-world basis: a group of scientists has identified a deep-sea creature that they are already dubbing a true zombie.
In a study published in Science Advances, researchers from Memorial University of Newfoundland, alongside Rachel Sipler from the Bigelow Laboratory for Ocean Sciences, have recorded the survival of amputated sea cucumber tissue for over three years in natural seawater.
This marks the first known report of extended survival—and sustained growth—of detached body parts outside of highly controlled and sterilized environments.
The findings question previous assumptions about the limits of cellular immortality in tissues not connected to their original organism and present promising avenues for biomedical applications.
Furthermore, the authors suggest this system could serve as an accessible experimental model for biological research, circumventing the ethical and logistical hurdles associated with many existing cell lines.
Sipler explained that while they haven’t yet grown a complete sea cucumber from these fragments, the observed results exceed initial expectations. “We haven’t grown a whole new sea cucumber, but we are seeing pretty incredible growth and cellular diversification years after this tissue was removed,” she stated. “It’s like a lizard losing its tail. We know some lizards can regrow a new tail; we’re talking about whether the tail can grow a new lizard.”
Since the mid-20th century, scientists have made significant strides in establishing so-called immortal cell lines, like the famous HeLa cells, which can be cultured in labs and propagated indefinitely for long-term study. However, in prior research, tissue cultures were maintained only under axenic conditions, meaning within a strictly controlled environment, meticulously maintained to be free of bacteria or other organisms.
Even in these exceptional cases, tissues did not exhibit effective healing or growth, nor did they retain the capacity for independent movement.
Many echinoderms, the phylum to which sea cucumbers belong, possess remarkable regenerative capabilities and minimal cellular senescence. However, it was presumed that any detached tissue would eventually decay or die.
Contrary to established belief, Sipler attributes the discovery’s origin to close observation: researchers noticed that some discarded tissue from a sea cucumber’s tube foot did not decompose over several weeks. Moreover, it appeared to continue growing.
Experiments were conducted using tissue samples extracted from the feet, main body, and tentacles of three individual Psolus fabricii, a species of cold-water sea cucumber. Researchers exposed the samples to flowing seawater and observed evidence of cellular diversification, immune activity, and tissue reorganization within the retrieved fragments.
In the absence of a mouth, the cells appeared to acquire nutrients by absorbing dissolved amino acids from the seawater. After three years, when the team decided to conclude the experiment for publication, the tissue remained active.
Sipler emphasizes that this ability to thrive in a complex and stressful environment makes this cell line unique compared to other tissue cultures. “Natural seawater is the least pure experimental approach with the most microbial diversity we could pick,” she stated. “Yet, this bacteria-rich environment and all this organic matter fed the cells and allowed this tissue to heal and grow.”
According to the study’s authors, this holds profound implications for biomedical sciences and engineering, with potential applications ranging from tissue regeneration to antimicrobial healing.
This discovery also opens new possibilities for biological research and education on a broader scale. The preserved tissue not only demonstrates an unprecedented capacity to maintain its structural integrity and complexity in culture but can also be more readily cultured in the lab and, as an invertebrate, is not subject to the extensive regulatory restrictions that apply to human or other vertebrate cell lines.
This characteristic makes it a valuable tool in settings with legal impediments or limited biosecurity infrastructure.
Andrea Bodnar, Scientific Director at the Gloucester Marine Genomics Institute, who was not involved in the study, remarked, “This discovery highlights that the ocean holds truly unexpected biological innovations. The fact that sea cucumber tissue explants can repair, reorganize, and survive independently for years in natural seawater suggests a whole new paradigm for biological resilience and tissue regeneration.”
For Sipler, an oceanographer by profession, this finding reinforces her belief in the untapped potential of marine life. “The best advances in science happen when you find a natural analog for what you’re studying,” she said. “Here, we have a species with innovative capabilities we didn’t even know existed. 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 truly valuable knowledge for us.”
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