title: Aging-associated endothelial dysfunction in humans is reversed by L-arginine.
abstract: OBJECTIVE
  This study investigated the hypothesis that aging selectively impairs endothelium-dependent function, which may be reversible by administration of L-arginine.
  
  
  BACKGROUND
  An impaired response to acetylcholine with aging has been demonstrated in humans. However, the mechanisms underlying this impaired response of the coronary microvasculature remain to be determined.
  
  
  METHODS
  We infused the endothelium-independent vasodilators papaverine and glyceryl trinitrate (GTN) and the endothelium-dependent vasodilator acetylcholine (1,3,10 and 30 micrograms/min) into the left coronary artery of 34 patients (27 to 73 years old) with atypical chest pain, negative exercise test results, completely normal findings on coronary angiography and no coronary risk factors. Coronary blood flow was measured with an intracoronary Doppler catheter. The papaverine and acetylcholine infusions were repeated in 14 patients (27 to 73 years old) after an intracoronary infusion of L-arginine (160 mumol/min for 20 min).
  
  
  RESULTS
  There was a significant negative correlation between aging and the peak coronary blood flow response evoked by acetylcholine (r = -0.73, p < 0.0001). However, there was no correlation to papaverine (r = -0.04, p = 0.82) and GTN (r = -0.24, p = 0.17). The peak coronary blood flow response evoked by acetylcholine correlated significantly with aging before L-arginine infusion (r = -0.87, p < 0.0001), but this negative correlation was lost after L-arginine infusion (r = -0.37, p = 0.19).
  
  
  CONCLUSIONS
  The results suggest that aging selectively impairs endothelium-dependent coronary microvascular function and that this impairment can be restored by administration of L-arginine, a precursor of nitric oxide.
authors.affiliation: Papworth Hospital, Cambridge, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Chauhan
authors.forename: R S
authors.initials: RS
authors.lastname: More
authors.forename: P A
authors.initials: PA
authors.lastname: Mullins
authors.forename: G
authors.initials: G
authors.lastname: Taylor
authors.forename: C
authors.initials: C
authors.lastname: Petch
authors.forename: P M
authors.initials: PM
authors.lastname: Schofield
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001120:Arginine / Q000494:pharmacology*; D003326:Coronary Circulation / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D005996:Nitroglycerin / Q000494:pharmacology; D010208:Papaverine / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; D001120:Arginine; D010208:Papaverine; D005996:Nitroglycerin; D000109:Acetylcholine