Adipose tissue-derived stem cells (ADSCs), a type of mesenchymal stem cells (MSCs), have great potential as therapeutic agents in regenerative medicine. Numerous animal studies have documented the multipotency of ADSCs, showing their capabilities to differentiate into tissues such as muscle, bone, cartilage, and tendon. However, the safety of autologous ADSC injections into human joints is only beginning to be understood and the data are lacking.
Between 2009 and 2010, 91 patients were treated with autologous ADSCs with platelet-rich plasma (PRP) for various orthopedic conditions. Stem cells in the form of stromal vascular fraction (SVF) were injected with PRP into various joints ( n = 100). All patients were followed for symptom improvement with visual analog score (VAS) at one month and three months. Approximately one third of the patients were followed up with third month magnetic resonance imaging (MRI) of the injected sites. All patients were followed up by telephone questionnaires every six months for up to 30 months.
The mean follow-up time for all patients was 26.62 ± 0.32 months. The follow-up time for patients who were treated in 2009 and early 2010 was close to three years. The relative mean VAS of patients at the end of one month follow-up was 6.55 ± 0.32, and at the end of three months follow-up was 4.43 ± 0.41. Post-procedure MRIs performed on one third of the patients at three months failed to demonstrate any tumor formation at the implant sites. Further, no tumor formation was reported in telephone long-term follow-ups. However, swelling of injected joints was common and was thought to be associated with death of stem cells. Also, tenosinovitis and tendonitis in elderly patients, all of which were either self-limited or were remedied with simple therapeutic measures, were common as well.
Using both MRI tracking and telephone follow ups in 100 joints in 91 patients treated, no neoplastic complications were detected at any ADSC implantation sites. Based on our longitudinal cohort, the autologous and uncultured ADSCs/PRP therapy in the form of SVF could be considered to be safe when used as percutaneous local injections.