Catechol-O-methyltransferase activity in psoriasis patients treated with psoralen plus ultraviolet A therapy

Authors

  • Pedro Souteiro,

    Corresponding author
    • Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
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  • Maria Augusta Vieira-Coelho,

    1. Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
    2. Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal
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  • Maria Paula Serrão,

    1. Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
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  • Sofia Magina

    1. Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal
    2. Institute for Molecular and Cell Biology, University of Porto, Porto, Portugal
    3. Dermatology and Venereology Department, Centro Hospitalar de São João, Porto, Portugal
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  • Conflicts of interest:

    None declared.

Correspondence:

Dr Pedro Souteiro, M.D., Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal.

Tel: +351 225513642

Fax: +351 225513643

e-mail: mimed07127@med.up.pt

Summary

Background

Catechol-O-methyltransferase (COMT) activity is increased in patients with mild/moderate psoriasis. Narrowband ultraviolet B (nbUVB) phototherapy decreases COMT activity. However, the effect of psoralen plus ultraviolet A (PUVA) on this enzyme activity is unknown, and it remains to be clarified if the nbUVB-induced effect in COMT activity is related to clinical response. The aim of this study is to evaluate COMT activity in moderate/severe psoriasis and assess whether PUVA therapy modifies this activity.

Methods

An observational study was conducted on 18 patients with moderate/severe psoriasis and 13 matched controls. Patients were treated with PUVA twice weekly during 6 weeks, and they were evaluated for Psoriasis Area and Severity Index (PASI) and COMT activity before photochemotherapy, at the end of it and 4 weeks after stopping.

Results

Before PUVA therapy, S(soluble)-COMT activity was significantly (P < 0.05) higher in psoriasis patients than in controls. After photochemotherapy, no significant differences were found in S-COMT activity at all end points. Photochemotherapy significantly decreased PASI but COMT activity values remained higher than those of control population.

Conclusion

Psoriasis patients with moderate/severe disease present higher S-COMT activity than controls. Although a good clinical response was observed, PUVA therapy does not change S-COMT activity. This differential COMT effect of PUVA and nbUVB suggests a wavelength-specific regulation.

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