The skin is composed of a variety of cells, of which keratinocytes and fibroblasts are the two key types of cells. Keratinocytes are mainly distributed in the epidermis, and through continuous division and migration, they build the barrier function of the skin. For detailed information about keratinocytes, please refer to relevant special articles. This article will focus on the function of fibroblasts and their role in skin aging.

Fibroblasts are the most common cell type in connective tissue, widely distributed in tissues such as skin, fat, heart, cornea, muscle, bone, blood and lymph, and are core cells that maintain tissue structure and function.

Fibroblasts have various morphologies, including spindle, polygonal and flat star. Their morphology varies depending on the cell function and attachment environment. The cells are large, the cytoplasm is weakly basophilic, the nucleus is large and oval, the chromatin is loose, and the nucleolus is obvious. Under an electron microscope, abundant rough endoplasmic reticulum, free ribosomes and developed Golgi complexes can be seen in the cytoplasm. These structures indicate that fibroblasts have strong protein synthesis and secretion capabilities.

Fibroblasts play a key role in tissue development, maintenance, repair, and inflammation regulation. Their main functions include:

Synthesis and remodeling of the extracellular matrix: Fibroblasts are the main synthesizers of the extracellular matrix (ECM), and can secrete components such as collagen, elastic fibers, reticular fibers, and organic matrix to maintain the structural integrity of connective tissue. In addition, they also promote the dynamic balance of tissues by secreting enzymes such as matrix metalloproteinases (MMPs) to remodel the ECM.

Trauma repair: After tissue damage, fibroblasts proliferate and differentiate to form new cells and extracellular matrix to promote wound healing. During fracture healing, fibroblasts can transform into osteocytes and participate in the repair and reconstruction of bone tissue.

Differentiation potential: Fibroblasts have a certain differentiation potential and can differentiate into other cell types, such as osteoblasts, under certain conditions.

Intercellular signaling: Fibroblasts regulate cell proliferation, angiogenesis, and ECM synthesis by secreting a variety of growth factors and cytokines (such as platelet-derived growth factor, transforming growth factor-β, and vascular endothelial growth factor).

Immunomodulation: Fibroblasts interact with immune cells, participate in inflammatory responses, regulate the recruitment and activity of immune cells, and clear bacteria and damaged tissues in wounds.

In the skin, fibroblasts are the core cells that maintain the structure, function and health of the skin. Their functions include:

Synthesis and remodeling of the extracellular matrix: Skin fibroblasts synthesize and secrete ECM components such as collagen, elastin, fibronectin, proteoglycans and laminin to provide structural support and elasticity for the skin. At the same time, they remodel the ECM through MMPs to promote wound healing.

Wound healing and tissue repair: When the skin is damaged, fibroblasts migrate to the wound area, proliferate and differentiate, and promote wound closure through contractile force. They also participate in inflammatory responses and the synthesis of new ECM, promote wound healing, and may cause scar formation. In addition, fibroblasts promote new blood vessel formation by secreting vascular endothelial growth factor (VEGF), providing oxygen and nutrients for wound healing.

Maintenance of stem cell microenvironment: Fibroblasts and the ECM they secrete provide the necessary microenvironment for skin stem cells to maintain their proliferation and differentiation capabilities. They regulate the proliferation and differentiation of stem cells by secreting growth factors and cytokines.

Development of skin appendages: Fibroblasts play a key role in the development of skin appendages such as hair follicles, sweat glands, and sebaceous glands.

With age, fibroblasts undergo a variety of changes that directly affect the structure, function, and appearance of the skin.

Decline in cell proliferation and function: The proliferation capacity of fibroblasts is weakened, and the rate of synthesizing ECM components slows down, causing the skin to lose elasticity and thickness.

Changes in collagen and elastin: The type of collagen synthesized by fibroblasts changes, and the ratio of collagen I to collagen III is unbalanced, affecting the strength and elasticity of the skin. At the same time, the degradation of elastin increases and the synthesis decreases, causing the skin to lose elasticity and wrinkles.

Decreased ECM remodeling ability: The ability of fibroblasts to remodel the ECM is weakened, which may lead to ECM structural disorder and affect the overall function of the skin. In the state of aging or disease, the wound repair ability of fibroblasts decreases, the wound healing speed slows down, and the healing quality decreases.

Weakened antioxidant capacity: The reduced antioxidant capacity of fibroblasts makes the skin more susceptible to free radical damage and accelerates the aging process.

High inflammatory state: Fibroblasts may show a higher inflammatory state, which is closely related to chronic inflammation and skin aging.

Changes in the stem cell microenvironment: The stem cell microenvironment composed of fibroblasts changes, affecting the function of skin stem cells, and then affecting the regeneration and repair ability of the skin.

Decreased responsiveness to growth factors: Fibroblasts become less responsive to growth factors, affecting their ability to repair and regenerate after injury.

Altered intercellular communication: The ability of fibroblasts to communicate with each other decreases with age, affecting their synergy and response to environmental changes.

Increased tendency to fibrosis and scarring: Fibroblasts are more likely to form fibrosis and scar tissue during aging, which is associated with poor wound healing and the appearance of skin aging.

Fibroblasts play a multifaceted role in maintaining the structure, function and health of the skin. However, with age, the function of fibroblasts gradually declines, causing the skin to lose elasticity and thickness, and its repair ability decreases, ultimately manifesting as aging characteristics such as skin sagging, wrinkle formation and reduced thickness. A deeper understanding of the mechanisms of fibroblast changes in skin aging will help develop interventions and treatments for skin aging.

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Foremed Legend

The core founding team of Suzhou Foremed Legend Medical Technology Co., Ltd. comes from well-known universities at home and abroad such as Peking University. Foremed Legend focuses on the design, research and development and application of high-end medical beauty optoelectronic equipment based on compliance and product strength. It is committed to becoming a leading company in the field of high-end medical beauty optoelectronic equipment, a provider of integrated diagnosis and treatment intelligent solutions, and a pioneer of medical beauty data integration platform.

Through the development of a series of underlying key technologies, Foremed Legend has independently developed a number of high-end medical devices, including picosecond laser therapy devices, long pulse laser therapy devices, intense pulsed light therapy devices, photoacoustic imaging skin detection devices, and cold air therapy devices. It continues to deepen the research and development of core product technologies, using better technical solutions to benefit the vast number of beauty seekers.

Adhering to the principle of technology for good, Foremed Legend will work with industry and ecological partners to bring more safe and effective medical beauty optoelectronic equipment and integrated diagnosis and treatment solutions to the global medical beauty market.