title: Recombinant human thyrotropin enhances endothelial-mediated vasodilation of conduit arteries.
abstract: BACKGROUND
  Endothelial cells possess receptors to TSH. Their role is largely unknown.
  
  
  OBJECTIVE
  The objective of the study was to determine whether elevated serum TSH levels, as occur in hypothyroidism, affect endothelial function of large arteries and vascular risk biomarkers.
  
  
  METHODS
  Thirty-four consecutively recruited patients, who had undergone thyroidectomy for thyroid carcinoma, were studied in connection with one of the monitoring procedures based on recombinant human (rh) TSH administration. Flow-mediated dilation (FMD) of the brachial artery and serum vascular risk markers were measured at baseline and for 5 d after the administration of rhTSH (0.9 mg im on d 1 and 2). Holter electrocardiogram and echocardiography were performed on d 2.
  
  
  RESULTS
  rhTSH caused a rapid increase in flow-mediated dilation from the basal value of 10.2 to 15.6% at 6 h (P < 0.0000001), to 16.1% on d 2 (P < 0.0000001), and to 14.9% on d 6 (P = 0.0015). The results were identical when the analysis was made in a subgroup of 19 patients free of vascular risk conditions. Vascular cell adhesion molecule-1, TNFalpha, IL-6, and high sensitive C-reactive protein were unaffected by rhTSH, whereas homocysteine was decreased. Arterial blood pressure, mean 24-h heart rate, and left ventricular function were unaffected by rhTSH.
  
  
  CONCLUSIONS
  rhTSH causes marked and persistent activation of the endothelial mediated vasodilation, independent of systemic hemodynamic changes.
authors.affiliation: Department of Internal Medicine and Cardiovascular Sciences, University Federico II, 80131 Naples, Italy. napoli@unina.it.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Napoli
authors.forename: Valentina
authors.initials: V
authors.lastname: Apuzzi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bosso
authors.forename: Carolina
authors.initials: C
authors.lastname: D'Anna
authors.forename: Antonietta
authors.initials: A
authors.lastname: De Sena
authors.forename: Concetta
authors.initials: C
authors.lastname: Pirozzi
authors.forename: Aldo
authors.initials: A
authors.lastname: Marano
authors.forename: Gelsy Arianna
authors.initials: GA
authors.lastname: Lupoli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cudemo
authors.forename: Ugo
authors.initials: U
authors.lastname: Oliviero
authors.forename: Margherita
authors.initials: M
authors.lastname: Matarazzo
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lupoli
authors.forename: Luigi
authors.initials: L
authors.lastname: Saccá
mesh_terms: D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology; D004562:Electrocardiography / Q000187:drug effects; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000494:pharmacology; D013972:Thyrotropin / Q000097:blood / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D011994:Recombinant Proteins; D013972:Thyrotropin