Endothelin-1 is significantly elevated in plasma of patients with vitiligo treated with psoralen plus ultraviolet A

BACKGROUND: Recent evidence suggests that systemic psoralen plus ultraviolet A (PUVA) therapy may have a stimulatory effect on melanocytes, not only locally but also systemically. Aim. We aimed to assess endothelin-1 (ET-1), a potent melanocyte mitogen, in plasma of PUVA-treated paients with vitiligo. METHODS: ET-1 was sequentially assessed (using ELISA) in patients with nonsegmental vitiligo treated with PUVA (n = 20), at 8, 16 and 24 h following the PUVA session. Evaluations took place at 0, 1 and 3 months of therapy. Patients with psoriasis (n = 15) treated identically and healthy subjects not receiving any therapy (n = 15) served as controls. Vitiligo Area Scoring Index (VASI) and Psoriasis Area Severity Index (PASI) scores were simultaneously evaluated. RESULTS: ET-1 was significantly lower in vitiligo than in psoriasis at month 0 (8.2 +/- 3.6 vs. 13.7 +/- 5.4 pg/mL; P = 0.03) and it was significantly higher in both than in healthy controls at all time points of the PUVA sessions (P < 0.001). In vitiligo, it significantly increased at month 3 at 8 (8.2 +/- 3.6 vs. 10.8 +/- 2.7 pg/mL; P = 0.02) and 16 h (8.2 +/- 3.6 vs. 11.5 +/- 3.9 pg/mL; P < 0.01), whereas in psoriasis, it significantly decreased at month 3 at 8 (13.7 +/- 5.4 vs. 3.5 +/- 0.4 pg/mL; P < 0.01) and 16 h (13.7 +/- 5.4 vs. 6.3 +/- 4 pg/mL; P = 0.01). In contrast to psoriasis, sequential values of vitiligo revealed insignificant variance (P > 0.05). VASI score significantly decreased at month 3 (19 +/- 9.6 vs. 11.9 +/- 7.3; P < 0.01), whereas PASI score significantly decreased at months 1 (38.2 +/- 16.1 vs. 13.8 +/- 3; P < 0.05) and 3 (38.2 +/- 16.1 vs. 7 +/- 2.6; P = 0.03). There was a significant indirect correlation of ET-1 with VASI score (P < 0.01) and a significant direct correlation with PASI score (P < 0.01). CONCLUSION: Systemic PUVA therapy in vitiligo may have a generalized mitogenic effect on melanocytes through the release of ET-1 into the circulation.