Human adult mesenchymal stem cells (MSCs) were first identified by Friedenstein et al. when observing a group of cells that developed into fibroblastic colony forming cells (CFU-F). Ever since, the therapeutic uses and clinical applications of these cells have increased research and interest in this field. MSCs have the potential to be used in tissue engineering, gene therapy, transplants and tissue injuries. However, identifying these cells can be a challenge. Moreover, there are no articles bringing together and summarizing the cell surface markers of MSCs in adults. The purpose of this study is to summarize all the available information about the cell surface characterization of adult human MSCs by identifying and evaluating all the published literature in this field. We have found that the most commonly reported positive markers are CD105, CD90, CD44, CD73, CD29, CD13, CD34, CD146, CD106, CD54 and CD166. The most frequently reported negative markers are CD34, CD14, CD45, CD11b, CD49d, CD106, CD10 and CD31. A number of other cell surface markers including STRO-1, SH2, SH3, SH4, HLA-A, HLA-B, HLA-C, HLA-DR, HLA-I, DP, EMA, DQ (MHC Class II), CDIO5, Oct 4, Oct 4A, Nanog, Sox-2, TERT, Stat-3, fibroblast surface antigen, smooth muscle alpha-actin, vimentin, integrin subunits alpha4, alpha5, beta1, integrins alphavbeta3 and alphavbeta5 and ICAM-1 have also been reported. Nevertheless, there is great discrepancy and inconsistency concerning the information available on the cell surface profile of adult MSCs and we suggest that further research is needed in this field to overcome the problem.

Mesenchymal stem cells (MSCs) were first discovered by Friedenstein and his colleagues in 1976 from bone marrow. The unique property of these cells was their potential to develop into fibroblastic colony forming cells. Since Friedenstein’s discovery of these cells the interest in adult MSCs has been progressively growing. Nowadays MSCs are defined as undeveloped biological cells capable of proliferation, self renewal and regenerating tissues. All these properties of MSCs have been discovered in the past 35 years. MSCs can play a crucial role in tissue engineering, organogenesis, gene therapy, transplants as well as tissue injuries. These cells were mainly extracted from bone marrow but there have been additional sources for MSCs discovered in the laboratories including: muscle, dermis, trabecular bone, adipose tissue, periosteum, pericyte, blood, synovial membrane and so forth. The discovery of the alternative sources of MSCs helps widen the application of these cells in different areas of medicine. By way of illustration, they can be used in various therapeutic purposes such as tissue regeneration and repair in musculoskeletal diseases including osteonecrosis of femoral head, stimulating growth in children with osteogenesis imperfecta, disc regeneration, osteoarthritis and duchenne muscular dystrophy. In order to fully comprehend the characteristics and potential of MSCs future studies in this field are essential.

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Unfortunately, significant hurdles remain and will need to be overcome before tissue engineering using MSCs becomes routine in clinical practice. Thus, further research and understanding are required into the safe and effective sourcing and application of mesenchymal stem cells in musculoskeletal applications.

The term tissue engineering is the technology that combines cells, engineering and biological/synthetic material in order to repair, replace or regenerate biological tissues such as bone, muscle, tendons and cartilage. The major human applications of tissue engineering are: skin, bone, cartilage, corneas, blood vessels, left mainstem bronchus and urinary structures. In this systematic review several criteria were identified as the most desirable characteristics of an ideal scaffold. These state that an ideal scaffolds needs to be biodegradable, possess mechanical strength, be highly porous, biocompatible, non-cytotoxic, non antigentic, stuitable for cell attachment, proliferation and differentiation, flexible and elastic, three dimensional, osteoconductive and support the transport of nutrients and metabolic waste. Subsequently, studies reporting on the various advantages and disadvantages of using collagen based scaffolds in musculoskeletal and cartilage tissue engineering were identified. The purpose of this review is to 1) provide a list of ideal characteristics of a scaffold as identified in the literature 2) identify different types of biological protein-based collagen scaffolds used in musculoskeletal and cartilage tissue engineering 3) assess how many of the criteria each scaffold type meets 4) weigh different scaffolds against each other according to their relative properties and shortcomings. The rationale behind this approach is that the ideal scaffold material has not yet been identified. Hence, this review will define how many of the identified ideal characteristics are fulfilled by natural collagen-based scaffolds and address the shortcomings of its use as found in the literature.