title: Endothelial nitric oxide synthase levels and their response to exercise in patients with slow coronary flow.
abstract: BACKGROUND
  Endothelial dysfunction plays a key role in the aetiopathogenesis of slow coronary flow (SCF) even if there is no obstructive epicardial lesion. Reduced plasma levels of endothelial nitric oxide synthase (eNOS) are an important indicator of endothelial dysfunction. We aimed to determine plasma levels of eNOS and their relationship with exercise in patients with SCF.
  
  
  METHODS
  Twenty-two patients with SCF in at least one coronary artery and 17 healthy individuals were included in this study. The TIMI frame count method was used to determine SCF. Plasma levels of eNOS before and after effort were determined in the patient and control groups.
  
  
  RESULTS
  Basal eNOS levels in the patient group were lower than in the control group (p = 0.040), and plasma eNOS levels after exercise decreased more significantly in the patient group compared to the control group (p = 0.002). Median decreases of eNOS in response to exercise were higher in the SCF group than in the control group (p < 0.001), and the decrease observed in the control group was not statistically significant (p = 0.35). There were significantly negative correlations between TIMI frame count and plasma levels of eNOS at baseline and after exercise (r = -0.51, p = 0.015, r = -0.58, p = 0.005, respectively). Moreover, there was also a positive correlation between the rate-pressure product and plasma levels of eNOS after exercise in patients with SCF (r = 0.494, p = 0.019).
  
  
  CONCLUSIONS
  Our findings indicate an important pathophysiological relationship between the severity of SCF in which endothelial dysfunction plays a role in its pathogenesis and the level of circulating plasma levels of eNOS.
authors: Department of Cardiology, Adiyaman University, Training and Research Hospital, Adiyaman, Turkey.
authors: Hakan
authors: H
authors: Taşolar
authors: Ferhat
authors: F
authors: Eyyüpkoca
authors: Erdal
authors: E
authors: Aktürk
authors: Yasin
authors: Y
authors: Karakuş
authors: Mehmet
authors: M
authors: Cansel
authors: Jülide
authors: J
authors: Yağmur
authors: Fatma
authors: F
authors: Ozyalin
authors: Burak
authors: B
authors: Altun
authors: Hasan
authors: H
authors: Pekdemir
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000201:enzymology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D015536:Down-Regulation; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000503:physiopathology; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D052250:Nitric Oxide Synthase Type III / Q000097:blood*; D054318:No-Reflow Phenomenon / Q000097:blood / Q000175:diagnosis / Q000201:enzymology* / Q000503:physiopathology; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III