title: Assessment of microvascular endothelial function in type 1 diabetes using laser speckle contrast imaging.
abstract: OBJECTIVE
  To test whether laser speckle contrast imaging (LSCI) coupled with physiological post-occlusive reactive hyperemia (PORH) and pharmacological iontophoresis of acetylcholine (ACh) as local vasodilator stimuli could distinguish between cutaneous microvascular responses of Type 1 Diabetes (T1DM)'s patients with endothelial dysfunction and that of healthy controls.
  
  
  METHODS
  Patients with T1DM aged ≥12years completed a clinical-epidemiological questionnaire. Data detailing patients' such as daily insulin dose, duration of diabetes, and use of pharmaceuticals such as antihypertensive drugs and statins that could interfere with endothelial function were obtained. Vascular reactivity was assessed in the forearm by LSCI and PORH at baseline and during iontophoresis of ACh using increasing anodic currents of 30, 60, 90, 120, 150 and 180μA in 10second intervals.
  
  
  RESULTS
  This study included 50 patients with T1DM and 30 control subjects. The mean resting flux did not differ between patients and control subjects. T1DM patients exhibited endothelial dysfunction upon challenge with physiological or pharmacological stimuli. The microvascular response to both ACh and PORH (i.e., maximum response at peak and amplitude) were significantly reduced in patients with diabetes compared with control subjects (p<0.001).
  
  
  CONCLUSIONS
  We demonstrated that endothelium-dependent skin microvascular vasodilator responses are significantly impaired in patients with T1DM compared to healthy subjects investigated using LSCI coupled with ACh iontophoresis and PORH. Additionally, we find that LSCI is a promising methodology for studying physiological vascular reactivity in T1DM.
authors.affiliation: Diabetes Unit, State University of Rio de Janeiro, Brazil. Electronic address: alessandramatheus79@yahoo.com.
authors.forename: Alessandra S
authors.initials: AS
authors.lastname: de M Matheus
authors.affiliation: Diabetes Unit, State University of Rio de Janeiro, Brazil.
authors.forename: Eliete Leão Silva
authors.initials: EL
authors.lastname: Clemente
authors.affiliation: Diabetes Unit, State University of Rio de Janeiro, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Guimarães Rodrigues
authors.affiliation: Diabetes Unit, State University of Rio de Janeiro, Brazil.
authors.forename: Débora Cristina
authors.initials: DC
authors.lastname: Torres Valença
authors.affiliation: Diabetes Unit, State University of Rio de Janeiro, Brazil.
authors.forename: Marília B
authors.initials: MB
authors.lastname: Gomes
mesh_terms: D000328:Adult; D058070:Asymptomatic Diseases; D003287:Contrast Media / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003925:Diabetic Angiopathies / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000503:physiopathology; D005260:Female; D005542:Forearm; D006785:Hospitals, University; D006801:Humans; D007478:Iontophoresis; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000503:physiopathology; D008875:Middle Aged; D010044:Outpatient Clinics, Hospital; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D012039:Regional Blood Flow / Q000187:drug effects; D012867:Skin / Q000098:blood supply / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology; D055815:Young Adult
chemical_list: D003287:Contrast Media; D014665:Vasodilator Agents
keywords: Acetylcholine; Endothelium; Laser speckle contrast imaging; Microvascular reactivity; Type 1 diabetes