title: Effect of skin temperature on skin endothelial function assessment.
abstract: OBJECTIVE
  Microcirculatory dysfunction plays a key role in the development of sepsis during which core temperature is often disturbed. Skin microvascular assessment using laser techniques has been suggested to evaluate microvascular dysfunction during sepsis, but skin microcirculation is also a major effector of human thermoregulation. Therefore we aimed to study the effect of skin temperature on endothelial- and non-endothelial microvascular responses.
  
  
  METHODS
  Fifteen healthy participants were studied at different randomized ambient temperatures leading to low (28.0+/-2.0 °C), intermediate (31.6+/-2.1 °C), and high (34.1+/-1.3 °C) skin temperatures. We measured skin blood flow using laser speckle contrast imaging on the forearm in response to vasodilator microvascular tests: acetylcholine (ACh) iontophoresis, sodium nitroprussiate (SNP) iontophoresis, and post-occlusive reactive hyperemia (PORH). The results are expressed as absolute (laser speckle perfusion units, LSPU) or normalized values (cutaneous vascular conductance, CVC in LSPU/mmHg and multiple of baseline).
  
  
  RESULTS
  Maximal vasodilation induced by these tests is modified by skin temperature. A low skin temperature induced a significant lower vasodilation for all microvascular tests when results are expressed either in absolute values or in CVC. For example, ACh peak was 57.6+/-19.6 LSPU, 66.8+/-22.2 LSPU and 88.5+/-13.0 LSPU for low, intermediate and high skin temperature respectively (p<0.05). When results are expressed in multiple of baseline, statistical difference disappeared.
  
  
  CONCLUSIONS
  These results suggest that skin temperature has to be well controlled when performing microvascular assessments in order to avoid any bias. The effect of skin temperature can be corrected by expressing the results in multiple of baseline.
authors.affiliation: Laboratory of Vascular Investigations, University Hospital of Angers, and L'UNAM University, University of Angers, Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM U 1083, Medicine Faculty, Angers, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Abraham
authors.forename: Mélissa
authors.initials: M
authors.lastname: Bourgeau
authors.forename: Maïte
authors.initials: M
authors.lastname: Camo
authors.forename: Anne
authors.initials: A
authors.lastname: Humeau-Heurtier
authors.forename: Sylvain
authors.initials: S
authors.lastname: Durand
authors.forename: Pascal
authors.initials: P
authors.lastname: Rousseau
authors.forename: Guillaume
authors.initials: G
authors.lastname: Mahe
mesh_terms: D000109:Acetylcholine / Q000737:chemistry / Q000494:pharmacology; D000328:Adult; D001783:Blood Flow Velocity; D003287:Contrast Media / Q000494:pharmacology; D004727:Endothelium / Q000473:pathology*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000378:metabolism; D007478:Iontophoresis / Q000379:methods; D008297:Male; D008833:Microcirculation; D009599:Nitroprusside / Q000494:pharmacology; D011897:Random Allocation; D012867:Skin / Q000473:pathology*; D012881:Skin Temperature; D013696:Temperature; D013997:Time Factors; D055815:Young Adult
chemical_list: D003287:Contrast Media; D009599:Nitroprusside; D000109:Acetylcholine