Endothelins (ETs), in addition to theft systemical activities, exert important functions at the skin level, such as increase of keratinocyte proliferation, neo-angiogenesis and leukocyte chemotaxis, which are among the main characteristics of psoriasis. To assess a possible ET-1 involvement in plaque-type psoriasis, ET-1 determinations were carried out in 15 sera and 8 lesional and non-lesional biopsy skin extracts from psoriatic patients and in 15 sera and 5 biopsy skin extracts from healthy volunteers, sex- and age- matched, using commercially available ELISA kits. A statistical analysis of the results showed that ET-1 levels were increased in sera of psoriatic patients, as compared to normal subjects (p=0.04). In addition, there was a significant correlation between both serum (r=0.60, p=0.02) and lesional skin (r=0.80, p=0.03) ET-1 values versus the Psoriasis Area and Severity Index scores. Significant increases of the lesional versus the non-lesional (p=0.01) and versus the normal (p=0.04) ET-1 skin extract values were observed, together with a significant correlation between lesional and non- lesional ET-1 skin levels (r=0.79, p = 0.03). These findings were also confirmed at the mRNA level, using RT-PCR analysis, where increased ET-1 mRNA levels, densitometrically measured, were found in the lesional samples versus non-lesional and normal skin. Since interleukin-8 is involved in psoriasis and shares some biological properties with ET-1, we further evaluated the levels of this cytokine in skin extracts. The behaviour of interleukin-8 paralleled that of ET-1, and a significant correlation between these two molecules was observed in the lesional skin (r=0.76, p=0.05). Taken together, these data stress that, as previously described for interleukin-8, ET-1 may be involved in inflammatory processes associated with psoriasis.
- PASI score
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