Background and objectives

Neither the pathogenesis of port wine stain (PWS) birthmarks nor tissue effects of pulsed dye laser (PDL) treatment of these lesions is fully understood. There are few published reports utilizing gene expression analysis in human PWS skin. We aim to compare gene expression in PWS before and after PDL, using DNA microarrays that represent most, if not all, human genes to obtain comprehensive molecular profiles of PWS lesions and PDL-associated tissue effects.

Materials and methods

Five human subjects had PDL treatment of their PWS. One week later, three biopsies were taken from each subject: normal skin (N); untreated PWS (PWS); PWS post-PDL (PWS + PDL). Samples included two lower extremity lesions, two facial lesions, and one facial nodule. High-quality total RNA isolated from skin biopsies was processed and applied to Affymetrix Human gene 1.0ST microarrays for gene expression analysis. We performed a 16 pair-wise comparison identifying either up- or down-regulated genes between N versus PWS and PWS versus PWS + PDL for four of the donor samples. The PWS nodule (nPWS) was analyzed separately.

Results

There was significant variation in gene expression profiles between individuals. By doing pair-wise comparisons between samples taken from the same donor, we were able to identify genes that may participate in the formation of PWS lesions and PDL tissue effects. Genes associated with immune, epidermal, and lipid metabolism were up-regulated in PWS skin. The nPWS exhibited more profound differences in gene expression than the rest of the samples, with significant differential expression of genes associated with angiogenesis, tumorigenesis, and inflammation.

Conclusion

In summary, gene expression profiles from N, PWS, and PWS + PDL demonstrated significant variation within samples from the same donor and between donors. By doing pair-wise comparisons between samples taken from the same donor and comparing these results between donors, we were able to identify genes that may participate in formation of PWS and PDL effects. Our preliminary results indicate changes in gene expression of angiogenesis-related genes, suggesting that dysregulation of angiogenic signals and/or components may contribute to PWS pathology.

Background and objective

Tissue effects of vascular lesion laser treatment are incompletely understood. Injury caused by pulsed dye laser (PDL) treatment may result in altered expression of mediators associated with angiogenesis.

Materials and methods

Eight human subjects had one angioma treated with PDL (7 mm, 1.5 millisecond pulse duration, 9 J/cm(2), cryogen spray cooling of 30 millisecond with a 30 millisecond delay). One week later, three biopsies were taken: normal skin, untreated angioma, angioma post-PDL. Tissue was frozen and sections processed for immunohistochemistry staining of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), matrix metalloproteinase 9 (MMP-9), and angiopoietin 2 (ANG-2). Images were graded in a blinded fashion by a board certified dermatopathologist.

Results

There were no clear trends in VEGF expression in the epidermis, dermis, or endothelial cells. As compared to normal skin, angiomas demonstrated the following: bFGF was decreased in the epidermis; MMP-9 was decreased or unchanged in the epidermis and increased in the endothelial cells; ANG-2 was increased in the endothelial cells. When comparing normal skin to angiomas + PDL, bFGF was decreased in the epidermis and increased in the dermis; MMP-9 was decreased or unchanged in the epidermis; ANG-2 was again increased in the endothelial cells. Comparison of staining in angioma to angioma + PDL samples revealed increased dermal bFGF expression.

Conclusion

Alterations in angiogenesis mediators were noted after PDL. Angiogenesis mediator changes associated with PDL treatment differed from those previously reported for incisional biopsies. This pilot study can guide future work on laser-induced alterations in vascular lesions and such information may ultimately be used to optimize treatment outcomes.