Osteoarthritis (OA) is a disabling condition that primarily affects articular cartilage. It is a significant cause of disability in adults, with a prevalence that is increasing in both women and men. The prevalence and incidence of OA are presumed to accelerate. This acceleration is due to the increase in life expectancy and sports activity of the general population as well as the progressive nature of OA. Mesenchymal Stem Cells are an option to treat OA.
OA can lead to a decrease in quality of life and an increase in healthcare costs. Many risk factors for developing OA include age, genetics, obesity, and previous joint injuries. There is no known cure for osteoarthritis, and current treatments do little to address the condition’s underlying causes.
Mesenchymal stem cells (MSCs) have shown promise as a treatment for generalized cartilage loss in osteoarthritis. However, midterm clinical and structural outcomes in studies have been limited. MSCs have helped to improve knee function and reduce pain. Further research is needed to understand the factors that influence the efficacy of MSC therapy for OA.
A study, Intra-articular Injection of Mesenchymal Stem Cells for the Treatment of Osteoarthritis of the Knee: A 2-Year Follow-up Study, looked into the midterm effects of stem cell therapy on knee OA patients.
Results of the Study
In 2014, the researchers performed a clinical trial to study the effectiveness of intra-articular injections of autologous adipose tissue-derived mesenchymal stem cells (AD MSCs) for treating knee osteoarthritis. The results of the trial showed that the AD MSCs were safe and effective in improving the symptoms of OA, as well as reducing radiological, arthroscopic, and histological evidence of the disease. The Improvements were seen at a 6-month follow-up and suggest that AD MSCs could be a potential treatment for knee OA. However, further research is needed to confirm these findings.
This study is a follow-up of a phase I/II clinical trial investigating the use of AD MSCs for treating patients with severe OA. The original trial included 18 patients divided into three cohorts and received different doses of the injection. The follow-up study included nine patients from the high-dose cohort. Patients in the follow-up study were asked to visit 1, 2, 3, and 6 months after the initial injection, and then again at one year and two years. The purpose of this follow-up was to evaluate the safety and efficacy of the injection at midterm.
Researchers used the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, Knee Society clinical rating system (KSS), and Knee injury and Osteoarthritis Outcome Score (KOOS). The WOMAC is a widely used measure of osteoarthritis severity that includes pain, stiffness, and physical function subscales. The VAS is a simple but effective measure of pain intensity with well-established reliability and validity. The KSS is a comprehensive measure of knee function that includes subscales for range of motion, strength, activities of daily living, sports and recreation, and satisfaction. KOOS is a newer measure that assesses symptoms, pain, activities of daily living, sport and recreation, quality of life, and knee-related emotions.
The study found that there were no significant adverse events during the follow-up period of 2 years. The WOMAC scores significantly decreased by 39.4%, 70.0%, and 64.9% at six months, one year, and two years, respectively, compared with baseline. However, no further improvement was noted after one year. Patients in the low- and medium-dose groups showed similar trends over two years and did not show sustained improvement.
The results of the study showed that the high-dose group had a significantly decreased VAS score for pain at six months, one year, and two years. The VAS score for pain in the high-dose group significantly decreased by 44.5%, 57.4%, and 42.5% at six months, one year, and two years compared to the VAS score before treatment. These findings suggest that patients may benefit from continued treatment after 1 year.
The knee subscore KSS at six months, one year, and two years significantly increased by 91.3%, 117.9%, and 71.9%, respectively, from the baseline values for the low-dose group and increased by 50.4%, 78.6%, and 68.0%, respectively, for the high-dose group. The function subscore of the KSS at six months, one year, and two years also increased by 38.8%, 50.0%, and 44.5%, respectively, from the baseline values for the low-dose group and increased by 9.5%, 18.5%, and 17.7%, respectively, for the high dose group.
These results suggest that outcomes could be closely related to the number of injected AD MSCs. Direct articular cartilage regeneration by injected cells might outweigh paracrine effects, although both mechanisms would work concurrently. Another important finding of the study is that it demonstrated solid structural and clinical evidence for the durability of regenerated articular cartilage after an intra-articular injection of AD MSCs. In summary, the study showed the continued safety and promising efficacy of an intra-articular injection of AD MSCs into the OA knee over two years, encouraging a larger randomized clinical trial.
Intra-articular Injection of Mesenchymal Stem Cells for the Treatment of Osteoarthritis of the Knee: A 2-Year Follow-up Study
