In modern regenerative medicine, mesenchymal stem cells (MSCs) represent one of the most promising therapeutic platforms, offering new opportunities for the treatment of traumatic injuries, degenerative disorders, and autoimmune diseases. However, the clinical effectiveness of MSC-based therapy depends primarily on the quality of the starting material and strict compliance with internationally recognized manufacturing standards.
Comprehensive quality control includes:
The International Society for Cell & Gene Therapy (ISCT) has established minimum criteria for defining human mesenchymal stem cells. According to these recommendations, MSCs must meet four key requirements.
MSCs must adhere to standard tissue culture plastic under conventional laboratory conditions. This characteristic enables their isolation, expansion, and evaluation throughout the manufacturing process.
MSC identity is confirmed by a characteristic immunophenotypic profile, including:
MSCs must demonstrate the ability to differentiate in vitro into three mesenchymal lineages:
The final cellular product must consist of a homogeneous MSC population and be free from microbial contamination, endotoxins, mycoplasma, and other biological contaminants.
At ReoCell, strict adherence to these international quality criteria ensures the safety, consistency, and therapeutic potential of every MSC product used in clinical practice.
The biological quality of an MSC product begins with donor selection. At ReoCell, donors undergo a comprehensive multistage evaluation based on biological, medical, and epidemiological criteria.
Donor age is one of the most important determinants of MSC quality. Numerous studies have demonstrated a strong correlation between donor age and the biological potential of mesenchymal stem cells.
Young MSCs possess longer telomeres—protective DNA structures located at the ends of chromosomes—which gradually shorten with each cell division. Aging is also associated with the accumulation of epigenetic modifications, including DNA methylation and histone acetylation, that progressively reduce regenerative capacity.
For this reason, ReoCell selects donors between 20 and 35 years of age, helping preserve the highest regenerative potential of harvested MSCs.
MSCs obtained from young donors typically demonstrate:
Ensuring the absence of blood-borne pathogens is a critical component of donor screening. At ReoCell, molecular diagnostic methods based on polymerase chain reaction (PCR) are used as part of Nucleic Acid Testing (NAT) to detect viral genetic material at the earliest possible stage of infection.
Compared with conventional serological testing, NAT methods can identify viral nucleic acids during the serological window period, significantly reducing the risk of undetected infection.
| Pathogen | Detection Window (NAT) | Detection Window (Serology) |
|---|---|---|
| HIV-1 | 8–33 days | 18–45 days |
| Hepatitis B virus (HBV) | 5–10 days | 30–60 days |
| Hepatitis C virus (HCV) | 4–10 days | 15–90 days |
| Human T-cell leukemia virus (HTLV) | 15–60 days | 30–180 days |
Donors with positive screening results are excluded from the donation program or undergo repeat testing after an appropriate follow-up interval.
One of the most common concerns associated with cell therapy is the potential risk of genetic alterations that could contribute to malignant transformation.
At ReoCell, this risk is minimized through comprehensive monitoring of genetic integrity throughout the manufacturing process.
G-banding is a standard cytogenetic technique used to visualize all 46 human chromosomes and detect chromosomal abnormalities.
This method enables the identification of both:
Because certain genetic alterations may remain undetectable by conventional cytogenetic analysis alone, current recommendations support combining G-banding with complementary molecular techniques to improve analytical sensitivity.
Prolonged cell culture may lead to progressive genetic and epigenetic instability, including:
To preserve genomic stability, ReoCell routinely performs karyotype analysis, monitors cellular morphology, and limits the number of culture passages used for clinical manufacturing.
Confirming the identity and safety of MSCs is only one aspect of quality control. Equally important is demonstrating that the cells retain their biological functionality.
The latest ISCT (2023–2025) recommendations emphasize comprehensive potency assessment, often referred to as the potency matrix, which integrates functional and molecular assays to evaluate the therapeutic capacity of MSCs.
One of the most important indicators of MSC quality is their proliferative capacity. This parameter is commonly evaluated using Population Doubling Time (PDT), which represents the time required for a cell population to double in number.
PDT is calculated using the following formula:
PDT = (t × log 2) / (log Nf – log N₀)
where:
Young, highly functional MSCs typically exhibit a PDT of 24–48 hours. As the number of culture passages increases, PDT gradually extends to 72–96 hours or longer, reflecting progressive cellular aging and reduced proliferative capacity.
For clinical applications, ReoCell uses MSCs with a PDT of less than 60 hours, ensuring high proliferative activity and optimal regenerative potential.
Flow cytometry is further employed to analyze the distribution of cells across different phases of the cell cycle (G0/G1, S, and G2/M) by measuring cellular DNA content.
Healthy young MSCs typically demonstrate the following distribution:
Significant deviations from these ranges may indicate cellular stress, senescence, or other functional abnormalities.
The Colony-Forming Unit-Fibroblast (CFU-F) assay remains one of the reference methods for evaluating the self-renewal capacity and proliferative potential of mesenchymal stem cells.
MSCs are seeded at a very low density (approximately 1–10 cells/cm²) in culture vessels. Individual cells proliferate independently, giving rise to visible colonies, each originating from a single progenitor cell.
The number of colonies formed directly reflects the clonogenic potential of the MSC population.
Young, healthy MSCs typically demonstrate a CFU-F efficiency of 20–40%, meaning that 20–40 colonies are formed for every 100 cells seeded.
By the fifth culture passage, this value generally declines to 5–15%, indicating progressive loss of self-renewal capacity associated with cellular aging.
Multipotency is one of the defining biological characteristics of mesenchymal stem cells and refers to their ability to differentiate into three mesenchymal lineages:
To confirm osteogenic differentiation, MSCs are cultured in osteogenic induction medium containing:
Successful differentiation is confirmed by the formation of mineralized extracellular matrix.
Chondrogenic potential is assessed by culturing MSCs under hypoxic conditions in the presence of transforming growth factor-β3 (TGF-β3), which stimulates cartilage matrix formation.
Adipogenic differentiation is induced using culture medium supplemented with:
Successful differentiation is confirmed by intracellular lipid accumulation characteristic of mature adipocytes.
Each cycle of cell expansion and transfer into a new culture vessel is referred to as a cell passage. According to the Hayflick limit, normal human cells can undergo approximately 40–60 population doublings before entering a state of replicative senescence, in which they progressively lose their functional properties.
Senescent MSCs are characterized by:
| Passage | PDT (hours) | CFU-F (%) | Multipotency | Cell Quality |
|---|---|---|---|---|
| P1–P2 | 24–36 | 35–40 | Full (+++) | Optimal |
| P3–P5 | 36–48 | 20–30 | Full (+++) | High |
| P6–P7 | 48–72 | 10–20 | Preserved (++) | Acceptable |
| P8+ | >72 | <10 | Reduced (+) | Unsuitable for clinical use |
As shown above, the optimal window for clinical application is within the first five to seven passages, when MSCs retain their highest proliferative capacity, multipotency, and regenerative potential.
For this reason, ReoCell strictly limits the number of culture passages, routinely monitors senescence-associated markers, and uses only early-passage MSCs for clinical applications.
Long-term storage and management of mesenchymal stem cell products are governed by internationally recognized quality standards, including ISO/TS 22859:2022 and ISO 24651:2022.
This standard establishes quality requirements for handling viable human cells and covers:
This standard provides guidance for the cryopreservation and long-term storage of MSCs, including:
At ReoCell, both standards are integrated into the quality management system, ensuring consistent product quality, long-term stability, and full traceability throughout the entire biobanking process.
The clinical success of mesenchymal stem cell therapy begins long before treatment. It depends on rigorous donor selection, comprehensive quality control, continuous monitoring of genetic stability, functional potency assessment, and strict compliance with internationally recognized manufacturing and biobanking standards.
Every stage—from donor screening and cell expansion to cryopreservation and final product release—contributes to the safety, consistency, and therapeutic potential of MSC-based therapies.
By implementing internationally recognized quality standards, ReoCell ensures that each MSC product meets stringent requirements for identity, purity, genetic stability, and biological functionality, providing a reliable foundation for safe and effective regenerative medicine.
Closing this window, you agree that you have read the information below.
SELF-MEDICATION CAN BE HARMFUL TO YOUR HEALTH!
