Key points in this article
In brief. “Living” cells are in an active metabolic state and retain 100% of their biological activity. “Frozen” (cryopreserved) cells recover basic functions after thawing but lose a significant part of their activity, especially immunomodulatory activity. Han's United works only with living cells and cultures them for 6 days for a specific patient. This affects dosing and clinical effect.
Why this question comes up when comparing clinics
“Living cells, not frozen” is the positioning of Han's United, and parents and patients often hear this phrase when comparing clinics. The logical question: is this a marketing category or a real clinical parameter? Below we look at both definitions, what independent studies say and what operational consequences this has for the patient and their family.
What “living” cells means
Living cells are in an active metabolic state. They have a complete cell structure and are capable of dividing, differentiating and interacting with body tissues. They are stored in an incubator at 37 °C in a CO₂ atmosphere and require continuous culture and medium.
Terminology. UC-MSCs: umbilical cord derived mesenchymal stem cells. P-MSCs: placenta-derived mesenchymal cells. Han's United works mainly with UC-MSC and P-MSC. (Han's United Glossary, 22 May 2024.)
When a clinic says “living cells”, it means that by the time of administration to the patient the material is in culture, has not undergone a freeze-thaw cycle and retains its full activity profile.
What “frozen” cells means
Cryopreserved cells are stored at ultra-low temperatures in liquid nitrogen at −196 °C. Their metabolism stops almost completely, a state called “hibernation” or anabiosis. After thawing, the cells recover basic functions but lose a significant part of their activity.
What is the biological reason for the loss of activity? The freeze-thaw cycle damages cell membranes with ice microcrystals, impairs mitochondrial function and activates some apoptotic signals. Some cells die immediately; others stay alive but with an altered functional profile.
What the peer-reviewed literature says
Han's United internal data estimate the loss of activity after thawing at 30-40%. This figure corresponds to the range described in independent scientific studies:
The systematic review by Bahsoun et al. 2019 (Journal of Translational Medicine, DOI: 10.1186/s12967-019-02136-7) analysed 41 in vitro studies of MSC cryopreservation. Viability immediately after thawing ranged from 50% to 100% depending on the protocol; 10 of the 41 studies recorded a statistically significant decrease in viability. Morphology, surface markers and differentiation potential are not affected, but functional parameters (migration, adhesion, immunomodulation) are described as “undefined” because of high variability between protocols.
Moll et al. 2014 (Stem Cells, DOI: 10.1002/stem.1729): a clinical comparison of fresh and cryopreserved MSCs showed a therapy response rate of 100% for fresh cells (n=5, early passage P1-2) versus 50% for cryopreserved cells (n=28, later passage P3-4). The difference approaches statistical significance (p=0.06). At the cellular level, cryopreserved MSCs showed a reduced response to pro-inflammatory stimuli, weaker production of anti-inflammatory mediators and increased activation of the complement system after contact with blood.
More about the mechanism of immunomodulatory activity loss. Moll et al. recorded several specific dysfunctions of cryopreserved MSCs: reduced mRNA expression of IDO (indoleamine-2,3-dioxygenase) after IFN-γ stimulation, with IDO being critical to the immunosuppressive action of MSCs; an 80% loss of viability after the cells contacted serum (50% for fresh MSCs); increased activation of complement-mediated lysis during infusion into the bloodstream; triggering of IBMIR, an instant blood-mediated inflammatory reaction.
Important: Moll 2014 is a study with a small sample (n=5 fresh vs n=28 cryopreserved), and the difference in response rate does not reach the classical threshold of statistical significance (p=0.06). This is a strong signal, but not RCT-level evidence. The systematic review by Bahsoun 2019 describes the functional changes as “undefined” because of variability between the protocols of different laboratories.
Conclusion from the combined literature: the difference between living and cryopreserved MSCs is a real clinical parameter that affects immunomodulatory activity and, probably, efficacy; the size of the effect depends on the quality of the specific clinic's protocol.
What changes at the level of clinical planning
If a clinic works with living cells, this affects several practical aspects:
Dosing. The active cell population is higher, so a smaller volume of cell material is needed for an equivalent effect. In cryopreserved protocols, part of the volume compensates for the loss of activity after thawing.
Preparation for the procedure. Living cells are cultured for a specific patient, usually for 6 days in the clinic's laboratory after the readiness of the material is confirmed; including examination and logistics, the full cycle takes 7-10 days.
Travel logistics. Cryopreserved cells can be kept “on the shelf” and used at any time. Living cells require agreed dates: the patient knows in advance exactly when preparation will finish and plans their arrival for that date.
Immunological profile. Fresh MSCs have a more stable immunomodulatory action. This is especially important in indications where the therapeutic effect depends directly on immunomodulation (autoimmune diseases, GVHD, neuroinflammatory processes).
What to ask a clinic when comparing
Before starting therapy, it helps to ask the clinic three direct questions:
What type of cells is used: MSCs (mesenchymal), haematopoietic, immune? These are different products with different indications.
What state are the cells in at the time of administration: living or cryopreserved? If cryopreserved, how does the clinic account for the loss of activity in dosing?
What is the dosing based on: the patient's weight, the nature of the disease, the results of specific clinical studies?
If you get specific technical answers to these three questions, that is a good sign of an informed clinical team. If the answers are general and marketing-like, it is worth asking them again.
References
FAQ Han's United (汉氏联合): internal clinic materials on cell types, dosing and the preparation of living MSCs.
Moll G., Alm J.J., Davies L.C., von Bahr L., Heldring N., Stenbeck-Funke L., Hamad O.A., Hinsch R., Ignatowicz L., Locke M., Lönnies H., Lambris J.D., Teramura Y., Nilsson-Ekdahl K., Nilsson B., Le Blanc K. Do Cryopreserved Mesenchymal Stromal Cells Display Impaired Immunomodulatory and Therapeutic Properties? Stem Cells. 2014 Sep;32(9). DOI: 10.1002/stem.1729.
Bahsoun S., Coopman K., Akam E.C. The impact of cryopreservation on bone marrow-derived mesenchymal stem cells: a systematic review. Journal of Translational Medicine. 2019;17. DOI: 10.1186/s12967-019-02136-7.
Malgieri A., Kantzari E., Patrizi M.P., Gambardella S. Bone marrow and umbilical cord blood human mesenchymal stem cells: state of the art. Int J Clin Exp Med 2010; 3(4): 248-269.
Han's United Glossary (22 May 2024): trilingual definitions of UC-MSCs / P-MSCs (RU/EN/ZH).