Increased Expression of Nerve Growth Factor Receptor and Neural Endopeptidase in the Lesional Skin of Melasma

BACKGROUND Characteristic clinical features of melasma are symmetry of hyperpigmentation and distribution related to trigeminal nerves, which suggest that the neural involvement could play a part in the pathogenic mechanisms of pigmentation. OBJECTIVE To evaluate whether some neuropeptides and neurotrophins and their receptors were associated with the pathogenesis of melasma. METHODS To investigate the involvement of neuronal system and neuropeptides in melasma, we examined the expression of nerve growth factor receptor (NGFR) and neural endopeptidase (NEP) in melasma lesional and nonlesional skin. Skin biopsies were obtained from lesional and nonlesional facial skin of six Korean women with melasma. Confocal laser scanning microscopic examination and western blot were performed. RESULTS Melasma lesions showed markedly greater expression of NGFR and NEP than nonlesional skin. CONCLUSION We suggest that neuroactive molecules, including NGF, is one of the critical factors for the pathogenesis of melasma, which may directly affect the microenvironment around melanocytes through a NGFR immunoreactivity (NGFR-IR) nerve fiber pathway, and higher levels of NEP in melasma has an important role in regulation of melanogenesis. The authors have indicated no significant interest with commercial supporters.