New treatments for skin diseases are among the tremendous advances in the field of cell therapy. The introduction of cellular technology, especially the application of autologous stem cells in the treatment of skin diseases, has drawn considerable attention and anticipation in this field over the past decades. Accordingly, leading research centres around the world have initiated various projects in this area, resulting in the dramatic development of stem cell technology and strategic knowledge in industrialized countries. With this background in mind, the present write-up aimed to discuss the biological and functional properties of human skin fibroblast cell products.
Biology of Fibroblasts
Fibroblasts are the most abundant cells in connective tissues. They primarily contribute to the secretion of extrarenal-matrix prophylaxis material to maintain the structural integrity of connective tissues. They secrete the necessary precursors for the production of all extracellular matrix compounds, including the base material and its strands. Similar to other connective tissue cells, fibroblasts are derived from the mesenchyme. The intermediate filament secretes a protein called vimentin, which is used as an indicator for the identification of mesodermal origins.
Epithelial cells due to epithelial-mesenchymal transition can convert into fibroblasts and vice versa. Furthermore, fibroblasts can be converted to epithelial cells under certain conditions. Mesenchymal-epithelial transition is also known as mesenchymal-epithelial transition. Fibroblasts consist of collagen, glycosaminoglycan, lattice and elastic fibres, glycoproteins in the exocrine matrix, and thymic stromal lymphopoietin cytokines; growing fibroblasts also divide and form the base material.
Epithelial cells due to epithelial-mesenchymal transition can convert into fibroblasts and vice versa. Furthermore, fibroblasts can be converted to epithelial cells under certain conditions. Mesenchymal-epithelial transition is also known as mesenchymal-epithelial transition. Fibroblasts consist of collagen, glycosaminoglycan, lattice and elastic fibres, glycoproteins in the exocrine matrix, and thymic stromal lymphopoietin cytokines; growing fibroblasts also divide and form the base material.
Functions of fibroblasts
In recent years, various studies have been conducted to verify the capacity of fibroblasts to regenerate the skin structure. Tissue damage induces fibroblasts and mitosis. On the other hand, in injured areas, these cells initiate cellular signalling processes, proliferate and migrate to the wound, contribute to extracellular matrix production, and repair tissues. Extracellular matrix proteins act as a scaffold for the migration of inflammatory cells and the production of granular tissues.
Granular tissue formation provides a temporary substrate for strengthening epithelial tissues by keratinocytes. With the formation of fibroblasts, they produce contractile elements for ulcer closure and produce type I collagen in subsequent phases to accelerate the healing process. Collagen is the most common form of an extracellular envelope, which forms fibres in an extracellular environment; therefore, it determines the shape of tissues. Collagen is stored as a precursor in fibroblastic cells and is secreted to the extracellular medium. The injected fibroblasts stimulate the production of extracellular matrix proteins or skin tissue regeneration.
In 2011, Han Kim et al. stated that mesenchymal stem cells, along with collagen gel, improve wound healing. In their study, three areas in the dorsal area of rats were punched; one part received collagen gel alone, one part received collagen gel in addition to mesenchymal stem cells, and one part received none as the control. They observed that mesenchymal stem cells could significantly increase wound healing by activating matrix metalloproteinase 9 and vascular endothelial growth factor. The literature suggests the use of these cells in various therapeutic interventions, such as the treatment of ulcers due to surgery or burns, chronic ulcers, treatment resistance in diabetic ulcers, and shallow or deep wrinkles of the skin
Comparing Fibroblastic markers with mesenchymal stem cells
Fibroblasts and mesenchymal stem cells express different genes. These variations are attributed to specific receptors and different markers in comparison with other cells. As a result, fibroblasts and mesenchymal stem cells are used for therapeutic and research purposes. For instance, markers of CD26 and CD10 expression vary or are not expressed in the majority of mesenchymal cells.
Conclusion
In addition to phenotypic and genetic similarities between fibroblasts and mesenchymal stem cells, they both exert immunomodulatory effects by suppressing T cells and other lymphocytes. Emerging reports on cell-based clinical studies in regenerative medicine indicate that mesenchymal stem cells are the most commonly applied cells in phase three of clinical trials. However, it should be noted that fibroblasts, as end-stage differentiated cells, are much safer therapeutic products for the market.
