Mesenchymal stem cells (MSCs) have been of recent interest as adjuncts for ligament repair. However, the effect of these cells on the resident ligament fibroblasts has not yet been defined. In this study, we hypothesized that co-culture of MSCs and ligament fibroblasts would result in increases in the proliferative rate of the ligament fibroblasts and their expression of collagen-related genes, as well as differentiation of the MSCs down a fibroblastic pathway. In addition, we hypothesized that these effects would be dependent on the source of the MSCs. Porcine MSCs were isolated from both the retro-patellar fat pad (ADSCs) and the peripheral blood (PBMCs) and co-cultured with porcine anterior cruciate ligament (ACL) fibroblasts. Fibroblast migration, proliferation, and collagen gene expression were evaluated at time points up to 14 days. ADSCs had a greater effect on stimulating ACL-fibroblast proliferation and procollagen production, while PBMCs were more effective in stimulating ligament fibroblast migration. In addition, co-culture with the ACL fibroblasts led to significant increases in collagen gene expression for ADSCs, suggesting a differentiation of these cells down a fibroblastic pathway during the co-culture period. This was not seen for the PBMCs. Thus, the effects of MSCs on in situ ACL fibroblasts were found to be source dependent, and the choice of MSC source should take into account the different performance characteristic of each type of MSC.
[Show abstract][Hide abstract] ABSTRACT: Interactions within the same cell population (homotypic) and between different cell types (heterotypic) are essential for tissue development, repair, and homeostasis. To elucidate the underlying mechanisms of these cellular interactions, co-culture models have been used extensively to investigate the role of cell-cell physical contact, autocrine and/or paracrine interactions on cell function, as well as stem cell differentiation. Specifically, the mixed co-culture model is often optimal for interpreting the effects of cell-cell contact on cellular behavior in vitro, while indirect co-culture can be used to study the effects of paracrine signaling on cell reactions. Additionally, cell-cell contact can be controlled by establishing physical barriers, which are used to regulate spatial and temporal cell distribution patterns in co-culture. In this chapter, we describe a method for forming a removable permeable divider for temporally and spatially controlling cellular interactions. This model can be used to study the impact of both cell-cell contact and paracrine signaling on the behavior of the mixed population as a whole and on the response of each subpopulation of cells in co-culture.
[Show abstract][Hide abstract] ABSTRACT: Growth factors and cytokines (referred to collectively hereafter as GFs) control cell growth, proliferation, and differentiation via a network of inter and intracellular signaling pathways. There are striking parallels between the pathways involved in skin wound healing and those implicated in photoaging of the skin. In recent years, topical and injectable GFs have emerged as an intriguing therapeutic modality that can be harnessed for aesthetic and medical purposes. This article provides a review of available evidence for the role in skin regeneration of topical GFs, and of injectable GFs contained in autologous platelet-rich plasma (PRP). It presents data from recent studies of GFs, offers a discussion of their potential to serve as antiaging actives, and includes safety considerations. As studies of injectable GFs typically assume preexisting familiarity with PRP protocols and the theory behind them, explanatory notes are provided. An assessment is provided of the evidence gaps that exist currently between experimental observations regarding GFs and their proven clinical benefits. Data of evidence levels II and III support the use for skin rejuvenation of topical GFs derived from sources including secretions or lysate of human dermal fibroblasts, and secretions of the snail Cryptomphalus aspersa. GFs with associated stem cell proteins, secreted by human dermal fibroblasts under hypoxic stress, can accelerate skin healing after laser resurfacing. In vitro and animal studies, small case series of PRP-treated patients and one prospective clinical study of its variant, platelet-rich fibrin matrix (PRFM), suggest the value of injectable GFs for skin rejuvenation. However, data of higher power are required to expand this proof of concept into an evidence-based paradigm. The clinical applications of topical and injectable GFs are promising, and remain to be fully defined. With continued study, data of higher evidence level can be accrued and formulations can be developed that offer optimal clinical efficacy, safety, tolerability, and stability. Better understanding of the mechanism of action of GFs can potentially advance our general understanding of dermal signaling pathways, and hence of hyaluronic acid and other alloplastic fillers; and allow the development of protocols for synergistic combination of GFs with other skin rejuvenation modalities.
Facial Plastic Surgery 04/2014; 30(2):157-71. DOI:10.1055/s-0034-1372423 · 0.64 Impact Factor
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