On Sable Island, Nova Scotia, a field team collected gray seal placentas from the beach shortly after birth. The researchers wanted to study living cells from those samples, but they lacked the facilities to isolate and culture the cells on the island. In a November 6 study in Scientific Reports, Kaitlin N. Allen and colleagues describe how they froze pieces of placental artery in the field and established primary endothelial cell cultures months later.
From the beach to the cell culture lab
The researchers dissected arteries from placentas collected from two gray seals. They placed the tissue in a cell freezing medium and cooled it in a portable −80 °C freezer. Liquid nitrogen and dry ice were unavailable at the field site. The samples spent about seven weeks in −80 °C storage overall, with a temporary freezer temperature excursion during transport off the island. They then spent about one month in liquid nitrogen vapor before the researchers thawed and pooled the arterial tissue for cell isolation.
Endothelial cells line the inside of blood vessels. The team isolated cells from that inner surface after thawing, then grew them on fibronectin-coated culture dishes. The authors report that these were the first primary endothelial cell cultures established from gray seals.
How the researchers checked the cells
The cells proliferated after isolation. To check their identity, the researchers looked for VE-cadherin at cell junctions and measured expression of two endothelial markers, CD31 and CD144. They also measured cellular respiration after the cultures expanded, showing that the recovered cells supported a functional assay.
The study establishes that this specific tissue and storage sequence yielded a usable culture. Because the team pooled samples from two animals, it could not estimate recovery for each animal. The fresh cells used for comparison came from northern elephant seals, so species and preservation differed together. A matched comparison with fresh gray seal tissue would be needed to isolate the effects of freezing.
Decide what the sample needs to do after storage
The study offers a planning question for other sample workflows. What evidence would tell you that a stored sample still serves the experiment? If the goal is to establish a culture, growth may be the first checkpoint. If the goal is to study a specific cell type or function, build in a marker or functional assay that tests that outcome.
Document the time between collection and preservation, storage conditions, and transfers. That record gives the team receiving the sample a way to interpret the result when it comes out of storage.
Source
Allen, K. N., Burns, J. M., Vázquez-Medina, J. P., den Heyer, C. E., and Shero, M. R. Scientific Reports, November 6, 2026. Field-compatible tissue cryopreservation enables delayed endothelial cell culture. Peer-reviewed accepted manuscript and methods.
