How Long Can Stem Cells Stay Frozen? New Study Finds Cells Still Working After 13 Years

Some of the most common questions from parents considering stem cell storage are straightforward: how long can stem cells stay frozen, and will the cells still work in 10, 20, or 30 years? A new peer-reviewed study adds to a growing body of evidence that the answer is encouraging [2].

Why Does Freezing Matter For Stem Cells?

Stem cells cannot be kept alive at room temperature for years. Instead, they are cryopreserved – frozen with a protective solution and held at extremely low temperatures, so their biological activity is effectively paused until they are thawed [1].

Effective cryopreservation and storage methods have been developed for both haematopoietic (blood-forming) stem cells and mesenchymal stem cells, and these methods underpin cord blood banking and cell therapy manufacturing [1]. The key question has always been how well cells hold up over very long storage periods.

What Did The Turin Study Find?

Researchers at the University of Turin and the Cell Factory of the Regina Margherita Children’s Hospital, led by Dr Katia Mareschi and Dr Ivana Ferrero, thawed bone marrow-derived mesenchymal stromal cells that had been manufactured to Good Manufacturing Practice – the pharmaceutical quality standard – and stored frozen for more than a decade. The results were published in Scientific Reports on 31 August 2026 [2].

After an average of 13.2 years in storage, the cells showed [2]:

• High survival. Between 80% and 86% of the cells were viable after thawing.
• Genetic stability. The cells had a normal karyotype, meaning no chromosome damage was detected.
• Healthy growth. After a short adaptation phase, the cells multiplied normally again.
• Intact identity. The cells fully met the international criteria that define mesenchymal stromal cells [6], including the ability to become bone, fat, and cartilage cells.
• Working signals. The substances the cells release, known as the secretome, still calmed activated immune cells in the laboratory, with the clearest effect on CD8-positive T cells.

The team also found that two different thawing solutions performed equally well. They concluded that the findings support long-term biobanking and the use of frozen mesenchymal stromal cells as reliable sources of both viable therapeutic cells and biologically active secretome [2].

How Long Can Cord Blood Stem Cells Stay Frozen?

Cord blood has an even longer track record. The first cord blood transplant, reported in 1989, used frozen cord blood from a baby’s sibling to treat Fanconi anaemia [7]. Professor Hal Broxmeyer, one of the team behind that transplant, went on to test how well stored samples held up over time [7, 8].

In 2003, his team at Indiana University reported high-efficiency recovery of functional blood-forming stem and progenitor cells from cord blood frozen for 15 years [8]. In 2011, they reported that cord blood frozen for 21 to 23.5 years still yielded 80–100% recovery of key progenitor cells, and that stem cells from samples frozen for up to 21 years produced long-term engraftment in mice [3]. The same samples also contained working immune cells [3].

More recently, a 2023 study in Cell Reports Medicine found that cord blood frozen for up to 27 years contained similar numbers of blood-forming stem and progenitor cells to fresh and recently frozen samples, with highly functional cells that engrafted robustly in mouse models [4]. The authors concluded that length of storage alone should not rule out a cord blood unit for use [4].

Cells4Life has covered this history before, in How Long Can Cord Blood Be Cryogenically Stored?. The Turin study adds new evidence for mesenchymal stromal cells, the cell family found in cord tissue.

Do Long-Stored Samples Work In Patients?

Evidence from transplant medicine is reassuring. A study of 127 patients who received cord blood transplants included 42 units that had been frozen for between 5 and 11.8 years [9]. Length of storage did not affect the proportion of viable cells after thawing, nor how quickly patients’ blood counts recovered [9]. The number of stem cells in the unit before freezing mattered more than how long it had been stored [9].

What Does This Mean For Families Storing Cord Blood And Cord Tissue?

Taken together, these studies show that carefully frozen stem cells retain their identity, genetic stability, and function across decades of storage [2, 3, 4]. The Turin cells came from bone marrow, but they are mesenchymal stromal cells – the same family of cells that umbilical cord tissue is a rich, well-studied source of [5]. Cord tissue cells are young and plentiful, which makes them an attractive source for future therapies [5].

Cord blood, cord tissue, and placenta can only be collected at birth. Storing them preserves the option and ensures a matched sample is available should it be required, with evidence showing that correctly frozen cells stay in working order for many years. To learn more about umbilical cord stem cells and how you can preserve them, fill in the form below to request your free welcome pack.

References

1. Hunt, C. J. (2011). Cryopreservation of human stem cells for clinical application: A review. Transfusion Medicine and Hemotherapy, 38(2), 107–123. https://doi.org/10.1159/000326623
2. Mareschi, K., Ferrero, I., Banche Niclot, A. G. S., et al. (2026). Long-term stability of GMP cryopreserved mesenchymal stromal cells after 10 years of storage. Scientific Reports. https://doi.org/10.1038/s41598-026-66048-5
3. Broxmeyer, H. E., Lee, M. R., Hangoc, G., et al. (2011). Hematopoietic stem/progenitor cells, generation of induced pluripotent stem cells, and isolation of endothelial progenitors from 21- to 23.5-year cryopreserved cord blood. Blood, 117(18), 4773–4777. https://doi.org/10.1182/blood-2011-01-330514
4. Broxmeyer, H. E., et al. (2023). Insights into highly engraftable hematopoietic cells from 27-year cryopreserved umbilical cord blood. Cell Reports Medicine, 4(11), 101259. https://www.cell.com/cell-reports-medicine/fulltext/S2666-3791(23)00436-6
5. Nagamura-Inoue, T., & He, H. (2014). Umbilical cord-derived mesenchymal stem cells: Their advantages and potential clinical utility. World Journal of Stem Cells, 6(2), 195–202. https://doi.org/10.4252/wjsc.v6.i2.195
6. Dominici, M., Le Blanc, K., Mueller, I., et al. (2006). Minimal criteria for defining multipotent mesenchymal stromal cells. The International Society for Cellular Therapy position statement. Cytotherapy, 8(4), 315–317. https://doi.org/10.1080/14653240600855905
7. Gluckman, E., Broxmeyer, H. A., Auerbach, A. D., et al. (1989). Hematopoietic reconstitution in a patient with Fanconi’s anemia by means of umbilical-cord blood from an HLA-identical sibling. New England Journal of Medicine, 321(17), 1174–1178. https://doi.org/10.1056/NEJM198910263211707
8. Broxmeyer, H. E., Srour, E. F., Hangoc, G., et al. (2003). High-efficiency recovery of functional hematopoietic progenitor and stem cells from human cord blood cryopreserved for 15 years. Proceedings of the National Academy of Sciences, 100(2), 645–650. https://doi.org/10.1073/pnas.0237086100
9. Kurita, N., Frassoni, F., Chiba, S., & Podestà, M. (2015). Impact of length of cryopreservation and origin of cord blood units on hematologic recovery following cord blood transplantation. Bone Marrow Transplantation, 50, 818–821. https://doi.org/10.1038/bmt.2015.56