Knee osteoarthritis (OA) is one of the most prevalent degenerative joint diseases worldwide, characterised by the gradual degradation of articular cartilage, inflammation of the synovial membrane, subchondral bone sclerosis, and joint space narrowing. This progressive condition often leads to chronic pain, stiffness, decreased mobility, and significant impairment in quality of life. While conventional treatments such as analgesics, corticosteroid injections, and joint replacement surgery provide symptomatic relief, they do not reverse the degenerative process. In recent years, stem cell therapy, particularly using umbilical cord-derived mesenchymal stem cells (UC-MSC stem cell), has emerged as a promising solution to address the underlying pathology of osteoarthritis.
A vital aspect of UC-MSC stem cell therapy is the accurate identification of cell surface markers, which confirm the stem cells’ identity, purity, and functional potential. This article explores the role of UC-MSC stem cell and their surface marker profile in the treatment of knee osteoarthritis and highlights how this approach is revolutionising regenerative joint care.
Understanding UC-MSC Stem Cell in Osteoarthritis Management
UC-MSC stem cell are multipotent stromal cells isolated from Wharton’s jelly in the umbilical cord. These cells possess the ability to differentiate into chondrocytes, osteocytes, and adipocytes, making them ideally suited for cartilage regeneration and joint tissue repair. Unlike bone marrow-derived MSCs (BM-MSCs) or adipose-derived stem cell (ADSCs), UC-MSC stem cell are harvested through a non-invasive and ethically acceptable method, offering higher proliferation rates and lower immunogenicity.
In the context of knee OA, UC-MSC stem cell have been shown to:
- Reduce synovial inflammation by modulating immune cell activity
- Promote cartilage regeneration through paracrine signaling and direct differentiation
- Inhibit apoptosis in chondrocytes
- Enhance the production of extracellular matrix components such as type II collagen and aggrecan
Such multifaceted therapeutic effects support their growing application in orthopaedic regenerative medicine.
Why Surface Marker Profiling Is Essential
Before UC-MSC stem cell can be utilised in clinical practice, it is crucial to verify their phenotypic characteristics. This is accomplished through flow cytometry, which identifies specific cell surface antigens, also referred to as cluster of differentiation (CD) markers. These markers serve as biological indicators, confirming that the cells are indeed mesenchymal in origin and are free from contaminating lineages, such as hematopoietic or immune cells.
According to the International Society for Cellular Therapy (ISCT), a standardised profile of positive and negative surface markers must be used to classify mesenchymal stem cells. Adhering to this framework ensures consistency, safety, and efficacy in stem cell-based treatments.
UC-MSC Stem Cell Surface Marker Profile
UC-MSC stem cell are identified based on their expression of specific surface markers that define their identity and biological function.
Positive Surface Markers (Required Expression)
UC-MSC stem cell must express the following markers:
- CD73: An ectoenzyme involved in anti-inflammatory and immunomodulatory functions
- CD90 (Thy-1): Supports cell–cell interaction, adhesion, and migration
- CD105 (Endoglin): Participates in angiogenesis and cartilage repair
These markers confirm that the cells possess the key attributes of mesenchymal stem cells and are capable of initiating tissue repair, particularly in the damaged cartilage of the osteoarthritic knee.
Negative Surface Markers (Must Be Absent)
To ensure purity, UC-MSC stem cell must not express:
- CD34: A marker for hematopoietic progenitor cells
- CD45: A leukocyte common antigen found on all immune cells
- CD14 / CD11b: Monocyte/macrophage-specific markers
- CD19 / CD79α: B-cell lineage markers
- HLA-DR: A major histocompatibility complex (MHC) class II antigen linked to immune activation
The absence of these markers eliminates the risk of adverse immune responses and enhances the safety profile of UC-MSC-based therapies for knee OA.
Additional Markers Relevant to Cartilage Repair
Researchers often investigate supplementary markers that may further indicate the regenerative capacity of UC-MSC stem cell, particularly for orthopaedic applications:
- CD44: Involved in chondrocyte proliferation and matrix interaction
- CD29 (Integrin β1): Enhances adhesion to extracellular matrix, essential for cartilage structure
- CD146: Associated with perivascular cells and vascular support in joint tissues
- CD166 (ALCAM): Plays a role in cellular communication and inflammation resolution
Although not mandated by regulatory bodies, these markers provide deeper insight into the biological behavior of UC-MSC stem cell in joint regeneration contexts.
Clinical Evidence in Knee Osteoarthritis
Several clinical and preclinical studies have demonstrated the efficacy of UC-MSC stem cell in treating knee OA. Patients receiving intra-articular injections of UC-MSC stem cell have shown:
- Improved cartilage thickness, as measured by MRI and arthroscopy
- Reduced pain and stiffness, according to WOMAC and VAS scores
- Decreased joint inflammation, confirmed by synovial fluid analysis
- Improved knee function and range of motion
Furthermore, UC-MSC stem cell therapy may delay or reduce the need for total knee replacement surgery, offering a less invasive and biologically restorative alternative for patients with moderate to severe OA.
Regulatory Standards and Quality Assurance
All UC-MSC products intended for clinical use must comply with international standards such as those set by the FDA, EMA, and PIC/S. These include Good Manufacturing Practice (GMP) requirements, where surface marker profiling forms an essential component of identity, purity, and potency testing.
Stem cell facilities such as Vega Stem Cell strictly implement these protocols. Each batch of UC-MSC stem cell undergoes flow cytometric analysis to confirm compliance with ISCT guidelines, ensuring a safe, consistent, and effective product for therapeutic application.
Conclusion
As the burden of knee osteoarthritis continues to rise globally, innovative and regenerative solutions like UC-MSC stem cell therapy offer a transformative alternative to conventional treatment. Through accurate surface marker identification, UC-MSC stem cell can be precisely characterised, ensuring that only high-quality, safe, and functionally competent cells are delivered to patients.
By targeting inflammation, enhancing cartilage regeneration, and improving joint function, UC-MSC stem cell verified through their surface marker profile represent a new paradigm in the non-surgical management of knee osteoarthritis. As research evolves and clinical evidence accumulates, this cell-based therapy holds promise for improving mobility, reducing pain, and restoring quality of life for millions affected by degenerative joint disease.