title: Acute hyperglycemia reduces cerebrovascular reactivity: the role of glycemic variability.
abstract: BACKGROUND
  Cerebral vasomotor reactivity (CVR) is reduced in patients with diabetes mellitus (DM), and glucose variability (GV) might be responsible for cerebrovascular damage.
  
  
  OBJECTIVE
  Studying patients with insulin resistance without DM, we explored the role of GV in impairing CVR.
  
  
  METHODS
  We studied 18 metabolic syndrome (MS) patients without DM, 9 controls (C), and 26 patients with DM.
  
  
  METHODS
  Groups were compared in terms of CVR, GV, and 24-hour blood pressure. To evaluate the impact of acute hyperglycemia on CVR, a hyperglycemic clamp was performed in MS patients and controls.
  
  
  RESULTS
  Baseline CVR was reduced in DM vs C and MS (C vs DM = 20.2, 95% CI = 3.5-36.9, P = .014; and MS vs DM = 22.2, 95% CI = 8.6-35.8, P = .001), but similar between MS and C (MS vs C = 2.0, 95% CI = -14.7 to 18.7, P = .643). During acute hyperglycemia, CVR fell in MS and C to values comparable to DM. GV progressively increased from C to MS to DM. In MS, CVR at 120 minutes and GV displayed a negative correlation (r = -0.48, P = .043), which did not change after controlling for mean 24-hour systolic and diastolic blood pressure. In MS, the CVR reduction was significantly correlated to GV (r = 0.55, P = .02).
  
  
  CONCLUSIONS
  GV is increased in patients with MS but without DM and is the major predictor of CVR reduction induced by acute hyperglycemia, possibly representing the earliest cause of cerebrovascular damage in DM.
authors.affiliation: Unit of Endocrinology, Diabetes, and Metabolism (I.G., A.D.F., F.P., I.M., D.Y., S.F.); Department of Neurology (P.Pal., F.P.); and Fatebenefratelli Association for Research Unit of Internal Medicine (S.D., P.Pas.) and Service of Medical Statistics and Information Technology (S.D., P.Pas.), S. Giovanni Calibita Fatebenefratelli Hospital, 00186 Rome, Italy; Department of Systems Medicine (I.G., A.D.F., F.P., I.M., D.Y., D.L., S.F.), University of Rome Tor Vergata, 00133 Rome, Italy; Department of Neurology (P.Pal., R.A., F.V.), Campus Bio-Medico University, 00128 Rome, Italy; and Unit of Health Management (S.D.), Ministry of Health, Viale Giorgio Ribotta 5, 00144 Rome, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Giordani
authors.forename: Alessandra
authors.initials: A
authors.lastname: Di Flaviani
authors.forename: Fabiana
authors.initials: F
authors.lastname: Picconi
authors.forename: Ilaria
authors.initials: I
authors.lastname: Malandrucco
authors.forename: Dorina
authors.initials: D
authors.lastname: Ylli
authors.forename: Paola
authors.initials: P
authors.lastname: Palazzo
authors.forename: Riccardo
authors.initials: R
authors.lastname: Altavilla
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Vernieri
authors.forename: Francesco
authors.initials: F
authors.lastname: Passarelli
authors.forename: Silvia
authors.initials: S
authors.lastname: Donno
authors.forename: Davide
authors.initials: D
authors.lastname: Lauro
authors.forename: Patrizio
authors.initials: P
authors.lastname: Pasqualetti
authors.forename: Simona
authors.initials: S
authors.lastname: Frontoni
mesh_terms: D000208:Acute Disease; D001786:Blood Glucose / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000503:physiopathology; D016022:Case-Control Studies; D002560:Cerebrovascular Circulation; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000503:physiopathology*; D007328:Insulin / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000503:physiopathology; D008875:Middle Aged; D014666:Vasomotor System / Q000503:physiopathology*
chemical_list: D001786:Blood Glucose; D007328:Insulin