Catecholamines' accumulation and their disturbed metabolism at perilesional site: a possible cause of vitiligo progression.

Catecholamines (epinephrine, norepinephrine and dopamine) are considered toxic to the melanocytes and may play an important role in the development of depigmented patches on the skin. This study was done to evaluate the levels of catecholamines in skin and plasma samples of active vitiligo patients' and gene expression changes in catecholamines' metabolism regulatory genes (COMT and GTPCH1), immunoregulatory genes (CTLA4 and PTPN22), and Catalase in active vitiligo patients. In this single-centre, prospective, case-control study, 30 patients with active vitiligo were recruited and skin biopsies from the perilesional site and plasma samples were collected. Skin biopsies from the normal site in vitiligo patients and healthy controls (n = 15) and plasma samples from controls were also obtained. Catecholamines' estimation was done via high-performance liquid chromatography. Gene expression variations were investigated via reverse transcription-polymerase chain reaction (PCR) and real-time PCR. Epinephrine, norepinephrine and dopamine levels were significantly higher in perilesional skin biopsies as compared to controls (P = 0.035, 0.024, and 0.006, respectively). However, epinephrine, norepinephrine and dopamine levels observed in patients' plasma samples were comparable to controls. The mRNA expression level of the Catalase gene was found to be upregulated at the perilesional site of patients as compared to the non-affected site of same patients (P < 0.001) and healthy controls (P = 0.037). Transcriptional expression of GTPCH1 and COMT were observed to be increased significantly at the perilesional site of patients in comparison to controls (P = 0.004 and P = 0.046, respectively). Our results support the presence of oxidative stress, inflammation and induced immune response in vitiligo patients at the perilesional sites. The increased inflammatory response may lead to catecholamines upregulation resulting in oxidative stress and melanocyte damage.