Photoaging is characterized by cellular changes and alterations in dermal extracellular matrix proteins with degeneration of connective tissue caused by intrinsic and extrinsic factors. The clinical manifestations of photoaging included wrinkles, pigmented changes, tissue loss, and sagging. Autologous platelet-rich plasma is a preparation of platelets in concentrated plasma from peripheral blood. The α granules of platelets contained many growth factors. According to previous literature, growth factors in platelet-rich plasma directly stimulate fibroblast proliferation to boost collagen production. It has also been shown to modulate extracellular matrix metabolism and remodeling by increasing the expression of specific matrix metalloproteinases. In review of previous literatures, there was only limited researches of platelet-rich plasma for treatment of photoaging. Therefore, the present study was conducted for analyzing the efficacy and safety of autologous platelet-rich plasma in photoaging therapy.

Autologous platelet-rich plasma is a preparation of platelets in concentrated plasma from peripheral blood. The α granules of platelets contained many growth factors, such as platelet-derived growth factor, transforming growth factor, vascular endothelial growth factor, and epithelial growth factor. These growth factors can trigger intracellular signaling cascades that ultimately alter gene expression and protein synthesis. Clinically, autologous platelet-rich plasma has been applied for treatment of hair loss, chronic wounds, and atrophic scars.

Photoaging is characterized by cellular changes and alterations in dermal extracellular matrix proteins with degeneration of connective tissue caused by intrinsic and extrinsic factors. The clinical manifestations of photoaging included wrinkles, pigmented changes, tissue loss, and sagging. The therapeutic modalities of photoaging included energy-based device, filler injection, and surgical treatment. However, there are some limitations and drawbacks of these therapies. For example, filler injection may cause foreign body granuloma, vascular occlusions, or tissue necrosis. Surgical treatment is an invasive procedure which may cause hematoma, infection, or scar formation.

According to previous literature, growth factors in platelet-rich plasma directly stimulate fibroblast proliferation to boost collagen production. It has also been shown to modulate extracellular matrix metabolism and remodeling by increasing the expression of specific matrix metalloproteinases. Platelet-rich plasma-enhanced expression of matrix metalloproteinases -1 and -3 helps clear photodamaged extracellular matrix components and allow for a better quality, more organized collagen meshwork. This process helps soften fine lines and minimize scarring. In addition, transforming growth factor and epithelial growth factor in platelet-rich plasma are known to modulate keratinocyte propagation and migration as well as repair barrier function. In review of previous literatures, there was only limited researches of platelet-rich plasma for treatment of photoaging. Therefore, the present study was conducted for analyzing the efficacy and safety of autologous platelet-rich plasma in photoaging therapy.

Inclusion criteria:

1. Men or female patients older than 20 years old with facial photoaging (Glogau Scale type II)
2. The photoaging severity of bilateral face is symmetric.

Exclusion criteria:

1. Patients with thrombocytopenia, coagulopathy, hematopoietic malignancy.
2. Patients with severe inflammation over treated area, malignancy, keloid, or poor wound healing history.
3. Patients had received laser, radiofrequency, ultherapy over treated area within 6 months.
4. Patients had received botulism or filler injection over treated area within 12 months.
5. Patients had received plastic surgery over treated area within 12 months.
6. Patients had severe psychiatric disorders with poor control.
7. Patients with other diseases which are not suitable for receiving platelet rich plasma (PRP) injection therapy.

We will not share IPD due to the privacy of participants.

1. The participants will blinded to receive platelet rich plasma and platelet poor plasma injections for treatment of photoaging of right side or left side of face.
2. The practitioner will inject these blood products into photoaging areas in bilateral face in each case without the knowledge of the content of injection materials.
3. The outcomes assessors will evaluate the response of the therapies without the knowledge of which blood products injected into bilateral face.