title: Quantification and visualization of cellular NAD(P)H in young and aged female facial skin with in vivo two-photon tomography.
abstract: BACKGROUND
  In vivo two-photon tomography is a novel noninvasive three-dimensional optical skin imaging technology with subcellular resolution which enables the sensitive detection of endogenous fluorophores. One of these fluorophores, NAD(P)H (a coenzyme which plays an important role in the release of free energy during glycolysis, and influences filaggrin and lipid synthesis), can be selectively detected in keratinocytes (granular cells) with two-photon tomography.
  
  
  OBJECTIVE
  To quantify NAD(P)H levels in subsurface human facial skin in vivo as a measure to determine if there are changes with age.
  
  
  METHODS
  A total of 80 healthy Asian females were enrolled in this study, aged 21-68 years. Measurements were performed on facial skin using in vivo two-photon tomography (DermaInspect/MPTflex™, JenLab GmbH, Jena, Germany). The laser beam scans a skin field of interest in pulses, focused at a depth to reach the granular layer. The near-infrared laser pulses excite the endogenous fluorophores NAD(P)H. Image processing was performed to obtain high-resolution autofluorescence images (optical biopsies) and to quantify the fluorescent grey scale to determine NAD(P)H levels. Additional skin surface measures taken were hydration (corneometer), elasticity (cutometer) and wrinkles (image capture and analysis).
  
  
  RESULTS
  Statistically significant changes in all measured parameters as a function of age were observed. Most importantly, the mean fluorescent grey scale values for NAD(P)H in the youngest group studied (women in their 20s) was 38.8 (SD ± 12.39), while that of the oldest group studied (women in their 60s) was 32.7 (SD ± 12.47). These NAD(P)H levels are statistically significantly different (P = 0.0078).
  
  
  CONCLUSIONS
  The level of NAD(P)H in the epidermis is significantly greater in younger vs. older skin in vivo. This likely reflects decreased production and/or increased degradation of NAD(P)H in older skin, possibly as a result of chronological ageing and environmental damage (e.g. photodamage). NAD(P)H levels in epidermal skin may be a useful biomarker of skin ageing in vivo. It is also likely that maintaining NAD(P)H production is a useful approach to maintaining good skin condition and caring for ageing skin.
authors.affiliation: R&D Prestige, P&G Innovation GK, 1-17 Koyo-cho Naka, Higashinada-ku, Kobe 658-0035, Japan. miyamoto.ku@pg.com
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: H
authors.initials: H
authors.lastname: Kudoh
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D015415:Biomarkers / Q000378:metabolism; D004817:Epidermis / Q000201:enzymology*; D005145:Face; D005260:Female; D000091344:Filaggrin Proteins; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008875:Middle Aged; D009249:NADP / Q000378:metabolism*; D015595:Skin Aging / Q000502:physiology*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
chemical_list: D015415:Biomarkers; C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D009249:NADP