title: Local burn versus local cold induced acute effects on in vivo microcirculation and histomorphology of the human skin.
abstract: BACKGROUND
  The impact of burns and colds on human skin microcirculation and histomorphology has not been compared as yet. Reflectance confocal microscopy (RCM) enables in vivo insight in human skin on cellular and subcellular levels. We evaluated analogies and differences of thermal injuries on microcirculation and histomorphology in vivo using RCM.
  
  
  METHODS
  Local superficial burn (6 female, 4 male; aged 28.4 ± 2.9 years, burn group) versus superficial cold (4 female, 6 male; aged 30.4 ± 5.2 years, cold group) was induced on the dorsum of the hand in an experimental immersion hand model. In vivo RCM was performed prior (control), immediately (t1) and 15 minutes (t2) following thermal injury to evaluate: Individual blood cell flow (IBCF), functional capillary density (FCD), epidermal thickness (ET), and granular cell size (GCS).
  
  
  RESULTS
  In the burn group, IBCF was increased at t1 (78.02 ± 2.60/min) and remained elevated at t2 (84.16 ± 3.04/min). In the cold group, IBCF decreased at t1 (12.62 ± 2.12 min) and increased at t2 (74.24 ± 3.14/min, P < 0.05) compared to the controls (58.23 ± 3.21/min). FCD was 6.74 ± 0.52/mm(2) in controls and increased at both t1 (7.82 ± 0.72/mm(2)) and t2 (8.02 ± 0.81/mm(2)) in the burn group. In the cold group, FCD decreased at t1 (2.60 ± 0.42/mm(2)) and increased at t2 (7.92 ± 0.44/mm(2), P < 0.05). ET increased at both t1 (43.12 ± 4.08 μm, P > 0.05) and t2 (47.26 ± 4.72 μm, P < 0.05) in the burn group. In the cold group, ET decreased at t1 (39.92 ± 3.14 μm, P > 0.05) and increased at t2 (44.72 ± 4.06 μm, P < 0.05) compared to the controls (41.26 ± 3.82 μm). Control GCS was 726.9 ± 59.4 μm(2) and increased at both t1 (739.8 ± 69.8 μm(2), P > 0.05) and t2 (762.6 ± 71.4 μm(2), P < 0.05) in the burn group. In the cold group, GCS decreased at t1 (712.4 ± 53.8 μm(2), P > 0.05) and increased at t2 (742.6 ± 64.8 μm(2), P < 0.05).
  
  
  CONCLUSIONS
  Superficial burn induces more cellular destruction and cold leads to huge fluctuation in tissue perfusion, however, with moderate impact on histomorphology. The effect on dermal capillaries suggests a selective neural control and cold injuries might down-regulate this system, much more than burns can activate it.
authors.affiliation: Department of Plastic and Reconstructive Surgery, University of Essen, Essen, Germany. draltintas@gmail.com
authors.forename: Ahmet Ali
authors.initials: AA
authors.lastname: Altintas
authors.forename: Merlin
authors.initials: M
authors.lastname: Guggenheim
authors.forename: Arzu
authors.initials: A
authors.lastname: Oezcelik
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gehl
authors.forename: Matthias C
authors.initials: MC
authors.lastname: Aust
authors.forename: Mehmet Ali
authors.initials: MA
authors.lastname: Altintas
mesh_terms: D000328:Adult; D002056:Burns / Q000503:physiopathology*; D048429:Cell Size; D003080:Cold Temperature; D005260:Female; D006225:Hand / Q000033:anatomy & histology* / Q000098:blood supply*; D006230:Hand Injuries / Q000503:physiopathology; D006801:Humans; D008297:Male; D008833:Microcirculation; D018613:Microscopy, Confocal; D012039:Regional Blood Flow; D012867:Skin / Q000033:anatomy & histology* / Q000098:blood supply* / Q000166:cytology / Q000293:injuries