Implications of multipotent mesenchymal stromal cell aging

Biological Therapies in Regenerative Sports Medicine

Regenerative medicine seeks to harness the potential of cell biology for tissue replacement therapies, which will restore lost tissue functionality. Controlling and enhancing tissue healing is not just a matter of cells, but also of molecules and mechanical forces. We first describe the main biological technologies to boost musculoskeletal healing, including bone marrow and subcutaneous fat-derived regenerative products, as well as platelet-rich plasma and conditioned media. We provide some information describing possible mechanisms of action. We performed a literature search up to January 2016 searching for clinical outcomes following the use of cell therapies for sports conditions, tendons, and joints. The safety and efficacy of cell therapies for tendon conditions was examined in nine studies involving undifferentiated and differentiated (skin fibroblasts, tenocytes) cells. A total of 54 studies investigated the effects of mesenchymal stem-cell (MSC) products for joint conditions including anterior cruciate ligament, meniscus, and chondral lesions as well as osteoarthritis. In 22 studies, cellular products were injected intra-articularly, whereas in 32 studies MSC products were implanted during surgical/arthroscopic procedures. The heterogeneity of clinical conditions, cellular products, and approaches for delivery/implantation make comparability difficult. MSC products appear safe in the short- and mid-term, but studies with a long follow-up are scarce. Although the current number of randomized clinical studies is low, stem-cell products may have therapeutic potential. However, these regenerative technologies still need to be optimized.

Hutchinson-Gilford progeria syndrome as a model for vascular aging

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder caused by a de novo genetic mutation that leads to the accumulation of a splicing isoform of lamin A termed progerin. Progerin expression alters the organization of the nuclear lamina and chromatin. The life expectancy of HGPS patients is severely reduced due to critical cardiovascular defects. Progerin also accumulates in an age-dependent manner in the vascular cells of adults that do not carry genetic mutations associated with HGPS. The molecular mechanisms that lead to vascular dysfunction in HGPS may therefore also play a role in vascular aging. The vascular phenotypic and molecular changes observed in HGPS are strikingly similar to those seen with age, including increased senescence, altered mechanotransduction and stem cell exhaustion. This article discusses the similarities and differences between age-dependent and HGPS-related vascular aging to highlight the relevance of HGPS as a model for vascular aging. Induced pluripotent stem cells derived from HGPS patients are suggested as an attractive model to study vascular aging in order to develop novel approaches to treat cardiovascular disease.