title: Positive association between circulating free insulin-like growth factor-1 levels and coronary flow reserve in arterial systemic hypertension.
abstract: BACKGROUND
  The reduction of coronary flow reserve (CFR) found in arterial hypertension may be due to changes in afterload, left ventricular (LV) structure, and metabolic factors. Also, insulin-like growth factor-1 (IGF-1) may be associated with the magnitude of CFR in relation to its modulating action on cardiac and endothelial function.
  
  
  METHODS
  A total of 44 newly diagnosed, untreated hypertensive patients, who were free of diabetes mellitus and coronary artery disease, underwent M-mode analysis, second-harmonic Doppler echocardiographic assessment of CFR (dipyridamole infusion 0.56 mg/kg intravenously in four patients), determination of circulating free IGF-1, and insulin resistance. Based on CFR levels, hypertensive subjects were divided into two groups: 18 with normal CFR (> or = 2) and 26 with impaired CFR (<2).
  
  
  RESULTS
  Patients with normal CFR had lower diastolic blood pressure, heart rate, and LV mass index but higher free circulating IGF-I than patients with reduced CFR (P < .001). Insulin resistance was not significantly different between the two groups. In a first multilinear regression analysis that included demographic and echocardiographic variables, insulin resistance was independently associated with CFR (standardized beta coefficient = -0.31, P < .05) in the overall population. However, in a subsequent model which included also IGF-1, the relationship between insulin resistance and CFR disappeared, whereas IGF-1 was the main independent determinant of CFR (beta = 0.51, P < .0002).
  
  
  CONCLUSIONS
  Free IGF-1 circulating levels are independently associated with CFR in hypertensive individuals free of overt coronary artery disease. A possible beneficial effect exerted by IGF-1 on coronary blood flow may be supposed in arterial hypertension.
authors.affiliation: Department of Clinical and Experimental Medicine, Federico II University, Naples, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Galderisi
authors.forename: Pio
authors.initials: P
authors.lastname: Caso
authors.forename: Silvana
authors.initials: S
authors.lastname: Cicala
authors.forename: Luigi
authors.initials: L
authors.lastname: De Simone
authors.forename: Michelangela
authors.initials: M
authors.lastname: Barbieri
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vitale
authors.forename: Oreste
authors.initials: O
authors.lastname: de Divitiis
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Paolisso
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D015992:Body Mass Index; D003326:Coronary Circulation / Q000502:physiology*; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D007334:Insulin-Like Growth Factor I