Retrospective Analysis And Mechanism Study Of 5-aminolevulinic Acid Photodynamic Therapy For Malassezia Associated Cystic Acne

[Background]Photodynamic therapy with 5-aminolevulinic acid(ALA-PDT)can inhibit the growth of microorganisms and inflammation,Malassezia infection and acne often occur together,we speculate that ALA-PDT can effectively treat cystic acne with Malassezia infection.The relationship between Malassezia and host's immunoregulation has been controversial.It is thought that Malassezia may up regulate or down regulate local inflammatory response.Therefore,this study aims to explore the role of Malassezia in the treatment of cystic acne by ALA-PDT.At present,it is believed that ALA-PDT can induce fungal damage by producing a lot of ROS,but there is no study on the mechanism of Malassezia in vitro.Therefore,we intend to study the mechanism of ALA-PDT on Malassezia in vitro.[Objective]To analyze the relationship between Malassezia and cystic acne,and exploring the role of Malassezia in the treatment of cystic acne by ALA-PDT,and studying the mechanism of ALA-PDT to Malassezia in vitro to provide scientific basis for the treatment of Malassezia infectious diseases.[Methods]The clinical data of 48 patients with cystic acne who were treated with ALA-PDT were retrospectively analyzed.Patients with Malassezia infection comprised the observation group,and those without infection comprised the control group.All patients,lesions were assessed by the global acne grading system(GAGS)at the 4th,8th,12th and 24th week after the first ALA-PDT treatment,and the times of the occurrence and disappearance of adverse reactions were recorded.The differences between the two groups were compared.In vitro,untreated Malassezia and that treated with ALA-PDT were observed by transmission electron microscopy,and the levels of reactive oxygen species(ROS)and malondialdehyde(MDA),as well as the activities of superoxide dismutase(SOD)and glutathione peroxidase(GSH-PX),were detected.[Results]The infection rate of Malassezia in super serious acne group was higher than that in severe acne group(P<0.05).Before treatment,the scores of GAGS in the observation group were significantly higher than those in the control group(P<0.05);At the 4th,8th,12th and 24th week after the first treatment of ALA-PDT,the scores of GAGS in the observation group were higher than those in the control group,the differences were statistically significant(P<0.05).The scores of GAGS before the first ALA-PDT treatment were subtracted from the scores of GAGS at 4th,8th,12th and 24th week after treatment,the difference between the two groups was lower in the observation group at the 4th and 8th week,and higher in the observation group at the 12th and 24th week,except for the 8th week,the differences were statistically significant(P<0.05).The occurrence time of burning,pain,erythema,swelling,exudation,pigmentation and scar after treatment by ALA-PDT in the observation group was earlier than that in the control group,except for scar,there were significant differences between two groups(P<0.05),and the regression time of all adverse reactions in the observation group were later than that in the control group(P<0.05).In vitro,the cell wall of Malassezia treated with ALA-PDT was thinner and looser than that of untreated Malassezia,the cell structure of Malassezia treated without ALA-PDT was relatively complete by transmission electron microscopy.At the same time,a large amount of ROS was produced in ALA-PDT group compared with the blank control group(P<0.05),and the content of ROS produced by fungi in ALA-PDT group decreased after adding diphenyliodine(DPI)(P<0.05).The MDA content of ALA-PDT group was higher than that of the control group and DPI group,the difference was statistically significant(P<0.05).The activity of SOD and GSH-PX in ALA-PDT group was the lowest,and the difference was statistically significant(P<0.05).When DPI was added,the activity of SOD and GSH-PX in ALA-PDT group was higher than before.[Conclusions]The more serious lesion of cystic acne,the higher detection rate of Malassezia,and Malassezia infection has certain effect on the treatment reaction of cystic acne.ALA-PDT is a effective method for the treatment of cystic acne,but the adverse reactions occurred earlier and lasted longer in the group with Malassezia.The results of in vitro study indicate that ALA-PDT may be able to produce a large number of ROS and destroy the integrity of fungal cell wall to treat Malassezia associated cystic acne.