The team also found that the immortality of excised tissue is unique, as far as we know P. plants. The researchers conducted comparative experiments on tissues extracted from related sea cucumber species, and none showed equivalent tissue survival.
Zombie cucumbers
Back in 1951, doctors at Johns Hopkins Hospital in Baltimore took a sample of a malignant cervical tumor from Henrietta Lacks, a 31-year-old mother of five. When they then cultured these cells, they saw that they doubled in size every 24 hours in a never-ending cycle. HeLa cells, named after the patient, were the first example of cellular immortality discovered in humans. “It revolutionized cell biology and a lot of medical research,” Jobson said.
However, HeLa was just one type of cell. LiPfe offers a new experimental model that allows scientists to work with a piece of structured animal tissue that preserves its own immune function, cell cycle and nutrient uptake without the ethical concerns associated with experimenting on live animals. “Look on the evolutionary tree, cucumbers are relatively close to mammals, and they’ve been noted before as having potential for interdisciplinary research,” Jobson said.
The authors of the study also emphasize that the discovery of naturally immortal complex tissues challenges our traditional ideas about what it really means to be alive. “The question we get a lot is, ‘Are these tissues really alive?’ and here it gets kind of philosophical—we lovingly call them zombies,” Jobson said.
LiPfe explants are not dead because their tissues do not decay or deteriorate and absorb nutrients. On the other hand, LiPfe spheres do not reproduce, and reproduction is one of the essential characteristics of life. “They don’t become new sea cucumbers, but they are reshaped into the form that best suits them in their current state,” Jobson said. “So they operate as a whole new entity.”
Before addressing the philosophical dilemmas surrounding LiPfe, the team first wants to understand the basics. The first question is how to immortalize the tissue P. plants it actually works. “Is there something unique, rare, weird that we don’t see in other sea cucumbers that makes them do this?” Jobson was surprised. The second question is why it is there in the first place – does this ability have an evolutionary role, or is it really a by-product of a high regenerative capacity.
Ultimately, we don’t know how much yet P. plants they actually live with their immortal tissues. “That’s a great question,” Jobson said. “Unfortunately, there are very few tools that work for aging sea cucumbers.”
Science Advances, 2026. DOI: 10.1126/sciadv.aeb1394
