Rotator cuff tear
Rotator cuff tears are frequent shoulder problems that are usually dealt with by surgical repair. Despite improved surgical techniques, the tendon-to-bone healing rate is unsatisfactory due to difficulties in restoring the delicate transitional tissue between bone and tendon (Gomol et all., 2004; Valencia Mora et all., 2015). Although there is a lack of consensus as to whether the application of stem cells to enhance the rotator cuff healing is effective or not, some authors have developed different strategies for clinical application of the experimental findings.
Stem cells for tendon regeneration
While tendon have receive less attention than those of bone and cartilage in the filed of regenerative medicine, bone-tendon junction disorders such as rotator cuff tear or lateral epicondylitis can be intractable problems. A small number of clinical trial have been published in this field.
However, it is too early to draw any conclusion from theses studies at this time and further data will be needed in a greater pool of patients. Furthermore, several unsolved issues need to be addressed including the necessary number of injected cells, the need for multiple injection, the efficacy and safety of allogeneic cells versus autologous cell, and whether it could be applied in advanced osteoarthritis.
In summary, mesenchymal cells injection has been applied to patients to treat osteoarthritis by itself or in conjunction with additional surgical procedures including microfracture, high tibial osteotomy or partial meniscectomy. Hyaluronic acid, corticosteroid, or platelet lysate were also used along with stem cells in some studies. In addition to several uncontrolled studies, a few controlled studies using injection of either bone marrow-derived mesenchymal stem cells or adipose stem cells reported regeneration of articular cartilage or meniscus as well as symptomatic improvement.
As with bone marrow mesenchymal stem cell, there is a paucity of controlled clinical investigations on regeneration of articular cartilage using adipose stem cells. Pak et al. (Pak, 2011) used autologous adipose tissue derived stem cells in four patients, comprising two with knee ostearthritis and two with hip osteoarthritis, which produce positive results. Twelve weeks after treatment, the patient with knee osteoarthritis showed an increased medial meniscus height on MRI. A controlled, prospective study using injected adipose stem cells to treat osteoarthritis was performed by Jo et al.
Along with bone marrow mesenchymal stem cells, adipose stem cells have received attention for cartilage regeneration. Extensive investigations on chondrogenesisfrom adipose stem cells in the last 15 years provided the basis of clinical application (Zuk et al., 2001). As with bone marrow mesenchymal stem cells, there is a paucity of controlled clinical investigations on regeneration of articular cartilage using adipose stem cells.
The ability of mesenchymal stem cells to promote meniscus regeneration following partial meniscectomy, and the effects of mesenchymals on osteoarthritic changes in the knee were investigated in 55 patients. A single injection (50×10 or 150×10 allogeneic) was given within 7 to 10 day after meniscectomy while the control group received a sodium hyaluronate vehicle. Meniscal volume increased significantly-as determined by quantitative MRI-in patient treated with cell after 12 months. Patients with osteoarthritis changes, who received mesenchymal stem cells, experienced a significant reduction in pain compared with those who received the control (Vangness et al. 2014).