title: Investigation of the mechanism of action of nonablative pulsed-dye laser therapy in photorejuvenation and inflammatory acne vulgaris.
abstract: BACKGROUND
  Nonablative lasers are widely used for treatment of wrinkles, atrophic scars and acne. These lasers stimulate dermal remodelling and collagen production, but the early molecular stimulus for this is unknown. The mechanism of nonablative lasers in inflammatory acne is variously suggested to be damage either to sebaceous glands or to Propionibacterium acnes. Their effects on cytokine production are unknown.
  
  
  OBJECTIVE
  To assess the in vivo effects of a short pulse duration nonablative pulsed-dye laser (NA-PDL) previously used for photorejuvenation and treatment of acne, on cytokine production, P. acnes colonization density and sebum excretion rate (SER).
  
  
  METHODS
  We examined the effect of NA-PDL (NliteV; Chromogenex Light Technologies, Llanelli, U.K.) on P. acnes colonization before and after laser therapy using a scrub-wash technique and culture at 0 and 24 h (n = 15), on SER using absorptive tape at 0, 2, 4, 8 and 12 weeks (n = 19) and on cytokine mRNA using reverse transcription-polymerase chain reaction from skin biopsies at 0, 3 and 24 h (n = 8). Results NA-PDL had no effect on P. acnes or SER. Transforming growth factor (TGF)-beta1 mRNA increased fivefold after 24 h and 15-fold in two subjects (P = 0.012).
  
  
  CONCLUSIONS
  TGF-beta is known to be a potent stimulus for neocollagenesis and a pivotal immunosuppressive cytokine which promotes inflammation resolution. Its upregulation by NA-PDL provides a possible unifying molecular mechanism linking stimulation of dermal remodelling in photorejuvenation with inhibition of inflammation in acne. Damage to P. acnes or sebaceous glands cannot explain the effect of this device in acne.
authors.affiliation: Department of Dermatology, Hammersmith Hospital, Imperial College, London W12 0NN, UK. edwardseaton@hotmail.co.uk
authors.forename: E D
authors.initials: ED
authors.lastname: Seaton
authors.forename: P E
authors.initials: PE
authors.lastname: Mouser
authors.forename: A
authors.initials: A
authors.lastname: Charakida
authors.forename: S
authors.initials: S
authors.lastname: Alam
authors.forename: P M
authors.initials: PM
authors.lastname: Seldon
authors.forename: P E
authors.initials: PE
authors.lastname: Seldon
authors.forename: A C
authors.initials: AC
authors.lastname: Chu
mesh_terms: D000152:Acne Vulgaris / Q000378:metabolism / Q000382:microbiology / Q000532:radiotherapy; D000293:Adolescent; D000328:Adult; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression / Q000528:radiation effects; D006801:Humans; D028022:Low-Level Light Therapy; D008875:Middle Aged; D011425:Propionibacterium acnes / Q000528:radiation effects*; D012333:RNA, Messenger / Q000235:genetics; D012627:Sebaceous Glands / Q000528:radiation effects; D012629:Sebum / Q000378:metabolism*; D012867:Skin / Q000276:immunology / Q000382:microbiology* / Q000528:radiation effects; D015595:Skin Aging / Q000528:radiation effects
chemical_list: D016207:Cytokines; D012333:RNA, Messenger