MSCs are multipotent adult stem cells capable of developing into different cell types, such as chondrocytes (cartilage cells). In addition, they release bioactive molecules that, together, are known as the secretome, which helps regulate inflammation, repair tissues, and support joint regeneration.
Why Use Heterologous Stem Cells?
Consistency and youthfulness: they come from young donors, which gives them higher quality and greater regenerative potential than cells derived from elderly or ill patients themselves.
Convenience: they are more practical because they are ready to use and do not require harvesting or culturing cells from the patient
This offers advantages over the use of autologous cells (the patient’s own cells), especially in older individuals or those with metabolic diseases.*
How Do These Mesenchymal Stem Cells Work in the Knee?
Reduction of inflammation:
They secrete molecules such as PGE2, IL-10, and IDO, which modulate the immune response by activating anti-inflammatory macrophages (M2 phenotype) and calming chronic inflammation.
Cartilage protection and regeneration:
They stimulate chondrocyte survival through hepatocyte growth factor (HGF).
(This helps cartilage cells live longer.)
They release exosomes containing microRNAs that promote cartilage matrix synthesis and reduce degradation.
(This helps improve the tissue surrounding cartilage cells and prevents further cell loss.)
They improve mitochondrial health and reduce oxidative stress in chondrocytes.
(This reduces cellular stress and creates a healthier environment for them.)
They stimulate bone repair in the subchondral bone, strengthening support for the joint.
Clinical Evidence
Numerous studies have shown encouraging results:
Meta-analysis (2020): a review of 11 studies involving 558 patients concluded that MSCs significantly reduce pain (VAS) and improve joint function (WOMAC), without increasing adverse events.
Randomized study with heterologous MSCs (30 patients): MSC injections were compared with hyaluronic acid injections; the MSC group showed greater improvement in pain, function, and cartilage quality on MRI after one year.
Long-term studies with placenta-derived MSCs (heterologous): these showed functional and structural improvements in cartilage, with no major complications, even up to 7 years after injection.
Recommended dose: doses of 50 million to 100 million cells per session have been associated with significant improvement within the joint, helping reduce the need for additional sessions during the first year of treatment.
How Can This Help Delay Surgery?
Pain relief and improved function: many patients reduce or discontinue pain medications and regain mobility within 6 to 12 months.
Cartilage regeneration: quantitative MRI studies have shown improvements in the quality and thickness of the articular cartilage.
Prevention of complications and structural improvement: by improving the subchondral bone and reducing inflammation, progressive joint damage may be decreased.
This can delay or even prevent the need for knee replacement surgery, especially in intermediate stages of the disease.
Safety and Side Effects
Studies show high tolerability:
No serious adverse events have been detected after intra-articular injection of heterologous MSCs.
Some patients may experience mild fever or temporary discomfort in the knee, without major consequences.
Conclusion
Heterologous mesenchymal stem cells offer an innovative approach to the treatment of knee osteoarthritis. They act through anti-inflammatory and regenerative mechanisms that:
Relieve pain and improve mobility
Promote recovery of cartilage and subchondral bone
May delay joint replacement surgery
They are supported by clinical studies and scientific reviews. Although research is still ongoing, this treatment represents a safe and promising alternative for patients seeking to avoid surgery.
Written by Dr. Yosafat Auddifred, based on research and educational content published by various specialized medical sources.
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