Background: Melasma is a common acquired facial hyperpigmented skin disorder. Platelet-rich plasma (PRP) is autologous plasma containing higher than normal platelets concentrations. Recently, PRP has been used as a therapeutic modality in melasma with significant clinical improvement, possibly due to its abundant contents of growth factors such as TGF-β. The latter represents a natural multifunctional polypeptide that negatively regulates melanocyte differentiation and therefore reduces skin hyperpigmentation. To date, the expression pattern of TGF-β protein in skin of melasma patients following PRP injection is unknown. Here we hypothesize that "injection of PRP in the lesional skin of melasma patients is associated with alterations of TGF-β protein expression".Patients and Methods: The study included 20 adult patients with melasma. Autologous PRP was delivered into the lesional skin either through microneedling or as intradermal microinjections. TGF-β protein expression was immunohistochemically examined in the perilesional and lesional skins before and after PRP treatment and in the healthy skins of nine volunteers (control group).Results: TGF-β protein was expressed within the epidermis, dermal adnexal structures, vascular endothelium, nerves and arrector pili muscle fibers of the healthy skins (control group), perilesional and lesional skins of melasma patients before and after treatment with PRP. Before treatment with PRP, the expression ofTGF-β protein in the lesional (1.26 ± 0.41) and perilesional (1.68 ± 0.51) skins of melasma patients were significantly lower than that in the healthy skins (2.26 ± 0.37, p value<.05). After treatment with PRP, the expression of TGF-β protein was significantly increased in the lesional (2.15 ± 0.44) skin of melasma patients.Conclusions: Our study provides the first indication about increased TGF-β protein expression in skin of melasma patients after PRP treatment. The alterations of TGF-β protein in skin of melasma patients not only support its roles in the development of this condition but also have some therapeutic ramifications.
Keywords: Platelet rich plasma; TGF-β; melasma; therapy.