title: The evaluation of penile microvascular endothelial function using laser speckle contrast imaging in healthy volunteers.
abstract: OBJECTIVE
  The primary aim of this study was to evaluate the effectiveness of laser speckle contrast imaging (LSCI) coupled with transdermal iontophoretic delivery of acetylcholine (ACh) for the assessment of penile microvascular function. Additionally, we tested systemic microvascular function using both LSCI and ACh iontophoresis on the forearm.
  
  
  METHODS
  We assessed cutaneous, endothelium-dependent microvascular reactivity on the penis and forearm of healthy volunteers (aged 56.6 ± 1.0 years, n = 26) at rest and 60 min following the oral administration of the phosphodiesterase type 5 inhibitor (sildenafil: SIL, 100mg). LSCI was coupled with the iontophoresis of ACh using increasing anodal currents of 30, 60, 90, 120, 150 and 180 μA during 10-second intervals spaced 1 min apart.
  
  
  RESULTS
  Basal skin microvascular flow in the penis increased significantly following SIL administration. The endothelium-dependent skin microvascular vasodilator responses induced by ACh were also significantly enhanced following SIL administration for each of the following parameters: peak values of cutaneous vascular conductance (CVC); increases in CVC; and the area under the curve for ACh-induced vasodilation. ACh-induced microvascular vasodilation in the forearm was not modified by SIL. Finally, the administration of electric current alone did not affect penile microvascular flow.
  
  
  CONCLUSIONS
  LSCI appears to be a promising non-invasive technique for the evaluation of penile microvascular endothelial function. This methodology may be valuable for the evaluation of penile microvascular reactivity among patients with cardiovascular and metabolic diseases and to test the effectiveness of drugs used to treat vasculogenic erectile dysfunction.
authors.affiliation: Department of Clinical Research, National Institute of Cardiology, Rio de Janeiro, Brazil.
authors.forename: Valéria
authors.initials: V
authors.lastname: Verri
authors.affiliation: State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Andréa
authors.initials: A
authors.lastname: Brandão
authors.affiliation: Department of Clinical Research, National Institute of Cardiology, Rio de Janeiro, Brazil; Laboratory of Cardiovascular Investigation, Oswaldo Cruz Institute, Rio de Janeiro, Brazil. Electronic address: etibi@ioc.fiocruz.br.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tibirica
mesh_terms: D000109:Acetylcholine / Q000627:therapeutic use; D000368:Aged; D003430:Cross-Sectional Studies; D004566:Electrodes; D004730:Endothelium, Vascular / Q000473:pathology*; D064368:Healthy Volunteers; D006801:Humans; D007478:Iontophoresis; D017078:Laser-Doppler Flowmetry; D007834:Lasers; D008297:Male; D008833:Microcirculation; D055806:Microvessels / Q000473:pathology; D008875:Middle Aged; D010413:Penis / Q000098:blood supply* / Q000187:drug effects; D012039:Regional Blood Flow; D000068677:Sildenafil Citrate / Q000627:therapeutic use*; D012867:Skin / Q000098:blood supply* / Q000473:pathology; D014664:Vasodilation; D014665:Vasodilator Agents / Q000737:chemistry / Q000627:therapeutic use
chemical_list: D014665:Vasodilator Agents; D000068677:Sildenafil Citrate; D000109:Acetylcholine
keywords: Endothelial function; Erectile dysfunction; Laser speckle contrast imaging; Microvascular dysfunction; Penile microcirculation