Ex-vivo Tendon Repair Augmented with Bone Marrow Derived Mesenchymal Stem Cells Stimulated with Myostatin for Tenogenesis

Muscle-tendon Crosstalk During Muscle Wasting

In organisms from flies to mammals, the initial formation of a functional tendon is completely dependent on chemical signals from muscle (myokines). However, how myokines affect the maturation, maintenance, and regeneration of tendons as a function of age is completely unstudied. Here we discuss the role of four myokines - fibroblast growth factors (FGF), myostatin, the secreted protein acidic and rich in cysteine (SPARC), and miR-29 - in tendon development and hypothesize a role for these factors in the progressive changes in tendon structure and function as a result of muscle wasting (disuse, aging and disease). Because of the close relationship between mechanical loading and muscle and tendon regulation, disentangling muscle-tendon crosstalk from simple mechanical loading is experimentally quite difficult. Therefore, we propose an experimental framework that hopefully will be useful in demonstrating muscle-tendon crosstalk in vivo. Though understudied, the promise of a better understanding of muscle-tendon crosstalk is the development of new interventions that will improve tendon development, regeneration, and function throughout the lifespan.

Tissue-Engineered Grafts from Human Decellularized Extracellular Matrices: A Systematic Review and Future Perspectives

Tissue engineering and regenerative medicine involve many different artificial and biologic materials, frequently integrated in composite scaffolds, which can be repopulated with various cell types. One of the most promising scaffolds is decellularized allogeneic extracellular matrix (ECM) then recellularized by autologous or stem cells, in order to develop fully personalized clinical approaches. Decellularization protocols have to efficiently remove immunogenic cellular materials, maintaining the nonimmunogenic ECM, which is endowed with specific inductive/differentiating actions due to its architecture and bioactive factors. In the present paper, we review the available literature about the development of grafts from decellularized human tissues/organs. Human tissues may be obtained not only from surgery but also from cadavers, suggesting possible development of Human Tissue BioBanks from body donation programs. Many human tissues/organs have been decellularized for tissue engineering purposes, such as cartilage, bone, skeletal muscle, tendons, adipose tissue, heart, vessels, lung, dental pulp, intestine, liver, pancreas, kidney, gonads, uterus, childbirth products, cornea, and peripheral nerves. In vitro recellularizations have been reported with various cell types and procedures (seeding, injection, and perfusion). Conversely, studies about in vivo behaviour are poorly represented. Actually, the future challenge will be the development of human grafts to be implanted fully restored in all their structural/functional aspects.

Bone morphogenetic protein-12 inducing tenogenic differentiation of mesenchymal stem cells enhances healing of linea alba incision

The objective of this study was to investigate the curative effects of mesenchymal stem cells' tenogenic differentiation on linea alba incision healing induced by bone morphogenetic protein-12. Mesenchymal stem cells were isolated and induced by 10 ng/ml of bone morphogenetic protein-12 for 48 h. Expression of scleraxis, collagen I and collagen III were examined at 48 h, 5 and 7 days to investigate the tenogenic differentiation. The expression of scleraxis increases continually even in the absence of bone morphogenetic protein-12 for 5 days (P<0.01). The expression of collagen I and III requires persistent inducing. Then fifty Sprague-Dawley rats were randomly divided into five groups: negative control, positive control, sham group, native mesenchymal stem cells and tenogenically differentiated mesenchymal stem cells. Tensiometric testing and modified semiquantitative histological analysis were performed to explore the curative effects. The tension levels in the positive control, sham, native mesenchymal stem cells and tenogenically differentiated mesenchymal stem cells were 44, 41.8, 51.6 and 69.7%, respectively, compared with the negative control. Tenogenically differentiated mesenchymal stem cells exhibited a greater increase in tension compared with positive control, sham and native mesenchymal stem cell groups (P<0.05). From the sections stained with Masson's Trichrome, collagen organization and amount of tenogenically differentiated mesenchymal stem cells was better than the other three groups (P<0.05). In conclusion, mesenchymal stem cells' tenogenic differentiation induced by bone morphogenetic protein-12 can enhance linea alba incision healing.