Research Articles

To assess the clinical efficacy and safety of mesenchymal stem cell (MSC) treatment for osteoarthritis of the knee (KOA), a systematic electronic literature search was performed on PubMed, EMBASE and Web of Science. Studies published in English from the earliest record to December 2014 were searched using the following keywords: Cartilage defect, cartilage repair, osteoarthritis, KOA, stem cells, MSCs, bone marrow concentrate (BMC), adipose-derived mesenchymal stem cells, synovial-derived mesenchymal stem cells and peripheral blood-derived mesenchymal stem cells. The effect sizes of selected studies were determined by extracting pain scores from the visual analog scale and functional changes from International Knee Documentation Committee and Lysholm and Western Ontario and McMaster Universities Osteoarthritis Index before and after MSCs or reference treatments at 3, 6, 12, and 24 months. The factors were analyzed and the outcomes were modified after comparing the MSC group pooled values with the pretreatment baseline or between different treatment arms. A systematic search identified 18 clinical trials on this topic, including 10 single-arm prospective studies, four quasi-experimental studies and four randomized controlled trials that used BMCs to treat 565 patients with KOA in total. __MSC treatment in patients with KOA showed continual efficacy for 24 months compared with their pretreatment condition.__ Effectiveness of MSCs was improved at 12 and 24 months post-treatment, compared with at 3 and 6 months. No dose-responsive association in the MSCs numbers was demonstrated. However, patients with arthroscopic debridement, activation agent or lower degrees of Kellgren-Lawrence grade achieved improved outcomes. MSC application ameliorated the overall outcomes of patients with KOA, including pain relief and functional improvement from basal evaluations, particularly at 12 and 24 months after follow-up.

While mesenchymal stem cells represent an interesting cell source for regenerative medicine, several points have to be investigated to improve their use in clinical, and in particular in the elderly population. This work studied the proliferation capacity of mesenchymal stem cells isolated from human bone marrow in function of donor's age. Doubling time after in vitro culture, clonogenicity and phenotype were analyzed in 17 samples ranging from 3 to 85 years old (mean 47 ± 27). Results showed an increase in the doubling time for cell coming from old donor compared to cells coming from young ones. This was accompanied by a decrease in clonogenicity while no changes were observe in cell phenotype. In conclusion, this study showed an effect of donor's age on the proliferation capacity of mesenchymal stem cells isolated from bone marrow that was correlated to a decrease in clonogenicity. The comprehension of molecular mechanism involved in this process could help to improve the clinical application of mesenchymal stem cells.

__Increasing evidence suggests that the loss of functional stem cells may be important in the aging process.__ Our experiments were originally aimed at testing the idea that, in the specific case of age-related osteoporosis, declining function of osteogenic precursor cells might be at least partially responsible. To test this, aging female mice were transplanted with mesenchymal stem cells from aged or young male donors. We find that transplantation of young mesenchymal stem cells significantly slows the loss of bone density and, surprisingly, prolongs the life span of old mice. These observations lend further support to the idea that age-related diminution of stem cell number or function may play a critical role in age-related loss of bone density in aging animals and may be one determinant of overall longevity.