title: Mechanisms of acid reflux and how refluxed Acid extends proximally in patients with non-erosive reflux disease.
abstract: OBJECTIVE
  The mechanisms that cause acid reflux in patients with non-erosive reflux disease (NERD), including those that determine how acid extends proximally, are not yet clear.
  
  
  METHODS
  Concurrent esophageal manometry and pH monitoring were performed for 3 h after a meal in 13 patients with NERD, 12 with mild reflux esophagitis (RE), and 13 healthy subjects (HS).
  
  
  RESULTS
  Transient lower esophageal sphincter (LES) relaxation (TLESR) was the major mechanism of acid reflux in all three groups. LES pressure did not differ between the groups. At 2 cm above the LES, there were no differences between the three groups in the number of TLESR-related acid reflux episodes, rate of TLESRs and rate of acid reflux during TLESR. However, at 7 cm above the LES, the rate of acid reflux during TLESRs was significantly higher in patients with NERD (mean ± SEM 42.3 ± 4.8) than in those with mild RE (28.0 ± 3.8) and HS (10.8 ± 2.5).
  
  
  CONCLUSIONS
  TLESRs are the sole motor events underlying acid reflux episodes in patients with NERD. Acid extends proximally more readily in patients with NERD than in HS and those with mild RE.
authors.affiliation: Department of Gastroenterology, Nippon Medical School, Graduate School of Medicine, Tokyo, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Sano
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Iwakiri
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kawami
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Choitsu
authors.initials: C
authors.lastname: Sakamoto
mesh_terms: D000328:Adult; D000368:Aged; D049630:Esophageal Sphincter, Lower / Q000503:physiopathology*; D004942:Esophagitis, Peptic / Q000503:physiopathology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005764:Gastroesophageal Reflux / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009126:Muscle Relaxation