title: Clinical trial of a novel non-thermal LED array for reversal of photoaging: clinical, histologic, and surface profilometric results.
abstract: OBJECTIVE
  Photomodulation has been described as a process which modifies cell activity using light sources without thermal effect. The objective of this study was to investigate the use of a non-thermal low dose light emitting diode (LED) array for improving the appearance of photoaged subjects.
  
  
  METHODS
  This prospective study investigated a random cohort of patients (N = 90) with a wide range of photoaged skin treated by LED photomodulation using a full panel 590 nm non-thermal full face LED array delivering 0.1 J/cm(2) with a specific sequence of pulsing. Subjects were evaluated at 4, 8, 12, 18 weeks and 6 and 12 months after a series of 8 treatments delivered over 4 weeks. Data collected included stereotactic digital imaging, computerized optical digital profilometry, and peri-ocular biopsy histologic evaluations for standard stains and well as collagen synthetic and degradative pathway immunofluorescent staining.
  
  
  RESULTS
  Digital imaging data showed a reduction of signs of photoaging in 90% of subjects with smoother texture, reduction of peri-orbital rhytids, and reduction of erythema and pigmentation. Optical profilometry showed a 10% improvement by surface topographical measurements. Histologic data showed markedly increased collagen in the papillary dermis of 100% of post-treatment specimens (N = 10). Staining with anti-collagen I antibodies demonstrated a 28% (range: 10%-70%) average increase in density while staining with anti-matrixmetalloproteinase (MMP)-1 showed an average reduction of 4% (range: 2%-40%). No side effects or pain were noted.
  
  
  CONCLUSIONS
  Photomodulation to reverse photoaging is possible with a specific array of LEDs with a specific fluence using a precise pulsing or "code" sequence. Skin textural improvement by digital imaging and surface profilometry is accompanied by increased collagen I deposition with reduced MMP-1 (collagenase) activity in the papillary dermis. This technique is a safe and effective non-painful non-ablative modality for improvement of photoaging.
authors.affiliation: Maryland Laser Skin & Vein Institute, Hunt Valley, Maryland 21030, USA. rweiss@mdlaserskinvein.com
authors.forename: Robert A
authors.initials: RA
authors.lastname: Weiss
authors.forename: David H
authors.initials: DH
authors.lastname: McDaniel
authors.forename: Roy G
authors.initials: RG
authors.lastname: Geronemus
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Weiss
mesh_terms: D001707:Biopsy, Needle; D004311:Double-Blind Method; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010789:Phototherapy / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D015595:Skin Aging / Q000473:pathology*; D012871:Skin Diseases / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome