Animal Experimental Study Of Photodynamic Effects With Different Light Sources And Long-term Follow-up Of Curative Effect Of Port Wine Stains

Background:Port wine stain(PWS)birthmarks is a congenital capillary malformation which occurs in 0.3%-0.5%of newborns.Pulsed dye laser(PDL)is the gold standard for the treatment of PWS,but it has limited effect on dark-skinned Asian populations.In recent,photodynamic therapy(PDT)has been used as an alternative in China.The coherent light source KTP(532nm)and the incoherent light source LED(532 ±10 nm)have the same wavelength and both can be used as excitation light sources for PDT in the treatment of PWS,showing different safety and efficacy in clinic.Objective:In the first part of this study,leghorn chicken wattle was used as the animal model to explore the comparison of the effects of two kinds of PDT on vascular injury of chicken wattle dermis.And in the second part,four cases of over 10 years long-term follow-up of facial port wine stains treated with PDT to further verify the long-term effect of PDT in the treatment of PWS.Methods:In the first part of this study,leghorn chickens were divided into blank control group,LED-PDT group and KTP-PDT group.Photodynamic treatment was performed in each group with the same parameters(90mw/cm2,130J/cm2),and the blank control group did not do any treatment.The experimental areas of chicken wattles were observed and measured by photoacoustic imager and spectrophotometer on the 1 st,3rd,7th,14th and 28th the after PDT treatment.The samples of chicken wattles of each group obtained on 14th and 28th after treatment were taken for HE staining,and the samples obtained on 28th were stained with Sirius red.And in the second part,four patients with PWS diagnosed and treated in our hospital from April 2005 to April 2010 were selected for a long-term follow-up study,and the relevant clinical data and followup photos of these patients were collected.The plastic surgeons evaluated the curative effect according to the erythema photos before and after treatment and during this follow-up,and measured the chromatic value by spectrophotometer and vascular date by photoacoustic imager of the erythema residual area,regression area and contralateral normal area of all patients.The vascular diameter data of each patient were analyzed using one-way ANOVA,and the color and vascular differences of the three regions were analyzed.Results:In the first part of this study,there were significant differences in vascular density reduction rate,capillary reduction rate and ΔE among the three groups 14 days after treatment,and those in KTP-PDT group was significantly higher than that in LED-PDT group.On the 28th day after treatment,there were significant differences in the ratio of type I collagen fibers to type III collagen fibers among the three groups,and the ratio in KTP-PDT group was higher than that in LED-PDT group.In the second part,the results of long-term follow-up case analysis showed that the ΔE between residual area and regression area were large,and ΔE between regression area and contralateral normal area were minimum.There was no statistical difference in vascular diameter among all patients,but the image showed that the vascular depth and vascular density in the residual area were much higher than those in the other two areas.Conclusion:The destructive effect of KTP-PDT on the superficial vessels of chicken wattles dermis is stronger than that of LED-PDT,but KTP-LED is not as safe as LED-PDT.The efficacy of PDT in the treatment of PWS is stable,and the skin with complete regression of erythema will not recur after PDT treatment.