Effect of oesophagitis on proximal extent of gastro-oesophageal reflux.

Abstract

Proximal oesophageal acid reflux is increased in gastro-oesophageal reflux disease (GORD) patients with oesophageal and extra-oesophageal symptoms, the latter particularly in presence of oesophagitis. This study was aimed to assess the proximal extent of reflux, both acid and weakly acidic, in GORD patients with and without oesophagitis and to characterize, using an animal model of GORD, the relationship between acute oesophagitis and proximal extent of reflux. Proximal extent of reflux was evaluated during 24-h pH-impedance monitoring in 17 oesophagitis, 27 non-erosive reflux disease (NERD) patients and 10 asymptomatic controls. In five adult cats, reflux events were simulated by intra-oesophageal retrograde injection of a radiopaque solution. Proximal extent of simulated reflux was fluoroscopically assessed before and after inducing acute oesophagitis. The percentage of proximal reflux was 11% in controls, 22% in NERD and 38% in oesophagitis patients (P < 0.05 vs NERD). Weakly acidic reflux showed higher proximal extent in oesophagitis than in NERD patients but it was less proximally propagated than acid reflux. In cats, proximal reflux was significantly increased during acute oesophagitis. Oesophagitis patients show higher proximal extent of reflux, acid and weakly acidic, when compared with NERD patients and controls. In the experimental model, acute oesophagitis favours proximal migration of simulated reflux.

Full text

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Effect of oesophagitis on proximal extent of gastro-
oesophageal reflux
S. EMERENZIANI,* M. CICALA,* X. ZHANG,? M. RIBOLSI,* R. CAVIGLIA,* M. P. L. GUARINO* & D. SIFRIM?
*Department of Digestive Disease, University Campus Bio Medico, Rome, Italy
?Centre for Gastroenterological Research, Gasthuisberg University Hospital, Leuven, Belgium
Abstract Proximal oesophageal acid reflux is increased
in gastro-oesophageal reflux disease (GORD) patients
with oesophageal and extra-oesophageal symptoms,
the latter particularly in presence of oesophagitis. This
study was aimed to assess the proximal extent of re-
flux, both acid and weakly acidic, in GORD patients
with and without oesophagitis and to characterize,
using an animal model of GORD, the relationship
between acute oesophagitis and proximal extent of
reflux. Proximal extent of reflux was evaluated during
24-h pH-impedance monitoring in 17 oesophagitis, 27
non-erosive reflux disease (NERD) patients and 10
asymptomatic controls. In five adult cats, reflux
events were simulated by intra-oesophageal retrograde
injection of a radiopaque solution. Proximal extent of
simulated reflux was fluoroscopically assessed before
and after inducing acute oesophagitis. The percentage
of proximal reflux was 11% in controls, 22% in NERD
and 38% in oesophagitis patients (P < 0.05 vs NERD).
Weakly acidic reflux showed higher proximal extent in
oesophagitis than in NERD patients but it was less
proximally propagated than acid reflux. In cats, prox-
imal reflux was significantly increased during acute
oesophagitis.Oesophagitis
proximal extent of reflux, acid and weakly acidic,
when compared with NERD patients and controls. In
the experimental model, acute oesophagitis favours
proximal migration of simulated reflux.
patientsshow higher
Keywords
disease, motility, pH-monitoring.
oesophagus, gastro-oesophagealreflux
INTRODUCTION
Proximal oesophageal extent of acid reflux is a
determinant of symptom elicitation in gastro-oeso-
phageal reflux disease (GORD) patients.1–3Previous
multi-sensor pH-studies have shown a higher per-
centage of proximal reflux in oesophagitis patients
whencomparedwith non-erosive
(NERD) patients and healthy controls.2Moreover,
proximal oesophageal and hypopharyngeal reflux are
increased amongpatients
symptoms and complications of GORD.4–8Indeed,
it has also been shown, in very large series, that
oesophagitis patients are at increased risk for laryn-
geal and pulmonary disease,9this finding having been
recently confirmed, in consecutive patients with
suspected GORD-related ENT symptoms.10At pre-
sent, data concerning the association between the
presence of erosive disease and proximal extent of
gastric reflux are lacking.
Among the factors possibly involved in favouring
proximal reflux,therole
responses to reflux, either peristaltic contractions or
oesophageal tone, is not fully understood. Changes in
oesophageal tone and length might, theoretically,
modulate the aboral progression of a bolus and the
proximal extentofreflux.
recentlybeen shown that
oesophagitis increases oesophageal tone and provokes
oesophageal shortening in cats.11In keeping with the
latter finding, intra-oesophageal acid perfusion, in
humans, causes an inflammation-related contraction
of the longitudinal muscle and oesophageal shorten-
ing.12
The aim of this study was to assess the proximal
extent of reflux, both acid and weakly acidic, in GORD
patients with and without oesophagitis and to confirm,
using an animal model of GORD, the relationship
between acute oesophagitis and proximal extent of
gastric reflux.
refluxdisease
withextra-oesophageal
ofoesophagealmotor
Interestingly,
experimental
ithas
acute
Address for correspondence
Dr. Sara Emerenziani, Department of Digestive Disease,
University Campus Bio Medico, Via E. Longoni, 83, 00155
Rome, Italy.
Tel.: +39 06 22541560; e-mail: s.emerenziani@unicampus.it
Received: 29 August 2006
Accepted for publication: 12 October 2006
Neurogastroenterol Motil (2007) 19, 459–464doi: 10.1111/j.1365-2982.2006.00868.x
? 2007 The Authors
Journal compilation ? 2007 Blackwell Publishing Ltd
459

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METHODS
Human study
Subjects A total of 49 consecutive patients complain-
ing of typical GORD symptoms – heartburn and/or acid
regurgitation – lasting more than 6 months, were
invited to take part in the study. All patients under-
went upper endoscopy, stationary oesophageal ma-
nometry and 24-h pH-impedance monitoring, the latter
performed 3–14 days (median 5 days) after endoscopy.
Following upper endoscopy, five patients were exclu-
ded from the study because of duodeno-gastric peptic
disease and/or Barrett oesophagus. Of the remaining
44 enrolled patients, 27 were NERD patients (16 men,
median age 46 years, range 31–57), showing a favour-
able response to proton pump inhibitors (PPI) treat-
ment (lasting £2 weeks) and no presence of erosive
disease at previous endoscopy, 17 patients (11 men,
median age 54 years, range 34–59) showed erosive
oesophagitis (grade I n ¼ 10, grade II n ¼ 7, according
to modified Savary–Miller classification). Hiatal her-
nia, defined as squamo-columnar junction ‡2 cm
proximal to the hiatal impression, was present in 9 of
27 NERD patients and in 7 of 17 oesophagitis patients.
PH-impedance data were compared with those of 10
asymptomatic, hospital staff volunteers (6 men, med-
ian age 34 years, range 31–47; healthy control group),
all non-smokers.
None of the patients had undergone previous
gastrointestinal surgery or was taking medication
known to influence oesophageal motor function.
Patients on antisecretory drugs stopped the medi-
cament at least 2 weeks prior to the study. The study
protocol was approved by the Ethics Committee of
University Campus Bio Medico of Rome and writ-
ten informed consent was obtained from all individ-
uals.
Intraluminal electrical impedance and pH Intralumi-
nal electrical impedance was recorded with a 2.3-mm
diameter polyvinyl assembly containing a series of
cylindrical electrodes, each 4 mm in axial length,
spaced at 2-cm intervals. Each pair of electrodes formed
a measuring segment, 2 cm in length, corresponding to
one recording channel (Sandhill Scientific Inc., High-
lands Ranch, CO, USA). The signals from the imped-
ance and pH channels were digitized at 50 Hz and
stored in a separate data logger (Sandhill Scientific
Inc.). Oesophageal pH was measured with an antimony
pH electrode. Before the start and at the end of the
recording, the pH electrodes were calibrated using pH
1.0 and pH 7.0 buffer solutions.
Patients and controls were studied after an overnight
fast of at least 10 h. Prior to the ambulatory study, all
subjects underwent stationary oesophageal manometry
to locate the lower oesophageal sphincter (LOS). After
the stationary manometry, the combined pH imped-
ance assembly was passed through the nose under
topical anaesthesia and positioned with the pH elec-
trode at 5 cm above the LOS. In this position, imped-
ance was measured at 3, 5, 7, 9, 15 and 17 cm proximal
to the LOS. Patients and controls were asked to remain
upright during the day, and to lie down only at their
usual bedtime. Event markers, on the monitor, had
recorded meal times and posture changes.
Data analysis In the analysis of impedance tracings,
liquid reflux was defined as a retrograde 50% drop in
impedance starting distally (at the level of the LOS) and
propagating to at least the next two more proximal
impedance measuring segments. Mixed liquid–gas re-
flux was defined as gas reflux occurring immediately
before or during a liquid reflux. Changes in oesophageal
pH during reflux detected by impedance allowed clas-
sification of reflux in (i) acid reflux: refluxed gastric
juice with a pH less than 4, which can either reduce the
pH of the oesophagus to below 4 or occur when oeso-
phageal pH is already below 4, (ii) weakly acidic reflux:
reflux events that result in an oesophageal pH between
4 and 7, and weakly alkaline reflux (iii) Weakly alka-
line reflux: reflux episodes during which nadir oeso-
phageal pH does not drop below 7.13
During reflux, drops of impedance, in the mid- and
upper oesophagus, indicated the proximal extent of the
liquid refluxate. Drops of impedance that reached the
distal measuring segment at 5 cm above LOS indicated
a distal not-propagated event. The percentage of reflux
episodes that reached the impedance segments in the
mid-oesophagus (15 cm above LOS) and proximal
oesophagus (17 cm above LOS) was calculated in
patients and controls.
Statistical analysis Data are expressed as mean ±
standard deviation (SD). In the analysis of pooled data,
the proportion of reflux events, acid and weakly acidic,
which reached the proximal oesophagus in controls,
NERD and oesophagitis patients, was compared using
Fisher’s exact test. A P value <0.05 was considered to
be significant.
Experimental model of gastro-oesophageal reflux
disease
Experimental studies were performed on five adult cats
weighing 3–5 kg underlightanaesthesiawith
S. Emerenziani et al.Neurogastroenterology and Motility
? 2007 The Authors
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460

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ketamine chloride (Parke-Davis, NV Warner-Lambert,
Zaventem, Belgium) at 15 mg kg)1i.m. injection for
induction and 10 mg kg)1i.m., every 30–45 min, for
maintenance.
The experimental protocol followed the Guiding
Principles For Research Involving Animals described in
the Declaration of Helsinki and was approved by the
Ethics Committee for Experimental Animals of the
Catholic University of Leuven, Belgium.
Gastro-oesophageal reflux simulation and recording
assembly An in vivo feline model was prepared to
simulate gastro-oesophageal reflux episodes using a
fast intra-oesophageal retrograde injection of a radio-
paque solution at a fixed flow rate using an angio-
graphic electronic pump.
The retrograde bolus injections were performed via a
percutaneous endoscopic gastrostomy (PEG) (Flocare
PEG Ch18F, Nutricia, Bornem, Belgium). The PEG was
performed under light
20 mg kg)1) and animals were allowed to recover for
7 days before the experimental procedures.
A polyvinyl injection
1.5 mm; outer diameter, 3 mm) was placed via the
gastrostomy with the tip located at the proximal
margin of the manometrically determined LOS. Reflux
events were simulated by fast retrograde injection of a
radiopaque solution (1 mL) at a fixed flow rate
(10 mL s)1) using an electronic pump (Medrad Inc.,
PA, USA) specially designed for cardiovascular/angio-
graphic injection procedures. The reflux simulation
experiments were performed with the animal’s body
and head elevated 30 ?. A radiopaque metric ruler was
placed lateral to the cat oesophagus.
Each reflux simulation event was recorded and the
fluoroscopic video was digitized (25 frames s)1) for
further analysis using a dedicated software for frame-
to-frame analysis.
anaesthesia (ketamine
tube(internal diameter,
Experimental acute oesophagitis Acute oesophagitis
was induced by intraluminal acid perfusion of a solu-
tion 0.1 N HCl at 1.0 mL min)1for 80 min at 1 cm
above the manometrically identified LOS using a
peristaltic pump. The degree of oesophageal mucosal
damage was evaluated endoscopically (Olympus CF,
type 1301, Japan) at 24 h. Buprenorphinum (Temge-
sic?; Schering-Plough, Brussels, Belgium) 0.3 mg day)1
was given as analgesic.
Study protocol Reflux simulation experiments were
performed before and 24 h after acid-perfusion-induced
acute oesophagitis. Experiments were performed with
three solutions of water-soluble radiographic contrast
medium (Gastrografine, Schering, Auckland, New
Zealand) of increasing viscosity containing 0%, 0.5%
and 1% of metilcellulose (MC). The viscosity of each
solution, measured in vitro at 38 ? (the normal body
temperatureof cat),was
8.66 mPas (0.5% MC) and 33.34 mPas (1% MC). The
latter viscosity was comparable to that obtained from
aspirated human gastric refluxate in the postprandial
phase.
1.98 mPas(0% MC),
Data analysis The proximal extent of simulated reflux
was measured using a metric ruler between the prox-
imal margin of the LOS (tip of injection catheter) and
the most proximal oesophageal site reached by the
bolus head (Fig. 1). The velocity of the simulated reflux
was calculated from the time interval (seconds)
A
B
Figure 1 Simulated gastro-oesophageal reflux. (A) Injection
was performed at proximal margin of the LOS. (B) Proximal
extent was 7 cm.
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between appearances of contrast at the proximal mar-
gin of LOS to the moment of maximal proximal extent
and divided by the distance (cm) observed between
these two points. The reproducibility of these param-
eters was tested in healthy cats. Reflux simulation
with the three different viscous solutions was per-
formed on three different days in each cat alternating
the order of viscosities.
Statistics Values are expressed as means ± SEM. The
differences in proximal extent and velocity of simula-
ted reflux were compared using one-way analysis of
variance followed by Dunn’s multiple comparison test.
The Student’s t-test for paired data was used to com-
pare these parameters before and after acute oesopha-
gitis. A P value <0.05 was considered to be significant.
RESULTS
Patients and controls
A total of 4428 reflux events were detected at distal
oesophageal level: mean 31 (range 17–82) in the healthy
controls; 73 (range 19–145) in NERD and 89 (range 25–
176) in oesophagitis patients, P < 0.001. Weakly acidic
reflux represented 55% of the total reflux events in
healthy controls, 28% in NERD and 26% in patients
with oesophagitis. Nearly two-thirds of weakly acidic
reflux occurred during the postprandial periods; liquid–
gas reflux accounted for 50–60% of reflux in all groups.
The dynamic characteristics of the reflux events in
the NERD, oesophagitis patients and healthy controls
are shown in Table 1. The patient groups showed a
higher percentage of proximal reflux, both acid and
weakly acidic, when compared with healthy controls.
Considering all reflux events, the percentage of prox-
imal reflux (at 17 cm above LOS) was 11% in healthy
controls, 22% in NERD patients and 38% in oesopha-
gitis patients (P < 0.05). Taking into consideration, the
acidity of the refluxate, acid reflux showed higher
proximal extent when compared with weakly acidic
reflux in patients and controls.
Experimental model of gastro-oesophageal reflux
disease: effects of acute oesophagitis on proximal
extent and velocity of retrograde flow
Acid perfusion provoked severe oesophagitis with
circumferential erosions, assessed by means of endo-
scopy, in the distal half of the oesophagus in all cats.
Before oesophagitis, the proximal extent of solution
with 0% MC was 6.2 ± 0.3 cm at a velocity of
5.5 ± 1.6 cm s)1whereas the solution with 1% MC
had a proximal extent of 4.5 ± 0.2 cm at a velocity of
1.0 ± 0.2 cm s)1(P < 0.05). These parameters did not
show significant difference between the three days
(P ¼ 0.1276). The proximal extent of simulated reflux
during oesophagitis was higher than in healthy cats
with the more viscous tested solution (1% MC:
P < 0.05, vs before oesophagitis) (Fig. 2A). During
oesophagitis, the velocities were slightly faster than
in healthy cats (Fig. 2B).
DISCUSSION
As far as concerned, the factors possibly involved in the
proximal spread of reflux, data on the role of oesopha-
gitis and on the characteristics of the refluxate are
lacking. Data from the present study demonstrate that
oesophagitis patients are characterized by a higher
proximal extent of reflux, both acid and weakly acidic,
compared with NERD patients and controls and that in
the experimental model of GORD, acute oesophagitis
does favour proximal migration of simulated reflux.
This finding, related to acid reflux, is in agreement
with a previous multi-channel pH-study showing a
higher perception of proximal reflux in NERD patients
but a higher percentage of proximal acid reflux in
oesophagitis compared with NERD patients and con-
trols.2We also assessed, for the first time and in a large
series, the dynamic characteristics of weakly acidic,
compared with acid, reflux: although weakly acidic
reflux showed higher proximal extent in oesophagitis
than in NERD patients and controls, it was less proxi-
mally propagated than acid reflux in all individuals.
Table 1 Percentage of proximal extent of acid and weakly acidic reflux (mean ± SD)
Controls NERD Oesophagitis
Total
(%)
Acid
(%)
Weakly
acidic (%)
Total
(%)
Acid
(%)
Weakly
acidic (%)
Total
(%)
Acid
(%)
Weakly
acidic (%)
15 cm above LOS
17 cm above LOS
27 ± 2
11 ± 2
24 ± 2*
15 ± 3*
17 ± 2
7 ± 2
39 ± 2**
22 ± 1**
44 ± 4*,**
29 ± 3*,**
27 ± 5**
16 ± 4**
59 ± 1**,***
38 ± 2**,***
62 ± 3*,**,***
39 ± 3*,**,***
45 ± 5**,***
23 ± 3**,***
*P < 0.05 vs weakly acidic, **P < 0.05 vs controls, ***P < 0.05 vs NERD.
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Previous studies have underlined the relevance of
proximal spread of the gastric refluxate on ENT
manifestations of GORD patients and the higher risk
of supra-oesophageal symptoms in the presence of
erosive disease.9In keeping with our findings of higher
proximal spread of gastric refluxate in oesophagitis
patients, a recent study, carried out in consecutive
patients with suspected GORD-related ENT symp-
toms, showed a significantly higher rate of symptom
relief following PPI treatment in the oesophagitis
group compared with those without oesophagitis.10
Although it is conceivable that the higher proximal
extent of reflux in oesophagitis patients is related to
the higher volume of refluxate, the presence of acute
oesophagitis is also associated with important changes
in the oesophageal tone.11In order to assess factors
possibly affecting proximal extent of reflux, in the
present study, we developed an experimental in vivo
model of GORD to simulate reflux events under
controlled circumstances. After inducing acute severe
oesophagitis, refluxate of increasing viscosities was
injected at the proximal margin of the LOS, at a fixed
pressure and volume, with the animal in resting
upright (30 ?) position. It was thus possible to evaluate
the effect of acute mucosal inflammation on the
proximal extent of reflux which was found to be
significantly increased during acute oesophagitis. Poss-
ible explanations for this finding could be: (i) oedema
associated with severe inflammation that might lead to
a narrower oesophageal lumen favouring a higher
proximal extent; (ii) increased oesophageal tone and
oesophageal shortening with impaired distension-in-
duced distal oesophageal accommodation and (iii)
impaired primary and secondary peristalsis during
severe mucosal inflammation.
Indeed, severe ineffective oesophageal motility may
be caused by various conditions and is strongly asso-
ciated with the presence of erosive disease.14
It has also been demonstrated that, in cats, acute
experimental oesophagitis induces severe oesophageal
motor dysfunction together with increased resting
oesophageal tone, decreased oesophageal compliance
and shortening of oesophageal length.11,12These chan-
ges might explain the enhancing role of oesophagitis on
the proximal extent of reflux.
Our experimental model of GORD also showed that
high-viscosity refluxate significantly decreases the
proximal extent of simulated reflux, maximally in
the absence of acute inflammation, whereas it reduces
the ascending velocity of retrograde flow both before
and after acute oesophagitis. Frictional resistance may
account for the lower proximal extent of the more
viscous solution. Another possible explanation could
be the different intraluminal distribution of the reflux-
ate due to an adaptive motor response. Distension of
the oesophagus, assessed by ultrasound as changes in
the cross-section area, linearly increases with the
increase in swallowed bolus volumes, the distal oeso-
phagus appearing to be the most compliant oesopha-
geal segment.15It might be hypothesized that high
viscous solutions, due to the slower transit, would
provoke a greater and longer lasting distension of the
very distal oesophagus. This distension might induce
relaxation at that level16with pooling of liquid more
distally, resulting in reduced maximal proximal extent.
Future studies assessing the viscosity of weakly acidic
reflux, likely more viscous than acid reflux, could
clarify the role, if any, of physical characteristics of
0
1
2
3
4
5
6
7
8
A
Proximal extent (cm)
B
0% MC0.5% MC1% MC
*
0
1
2
3
4
5
6
7
8
9
10
Velocity (cm/sec)
0% MC 0.5% MC1% MC
Before esophagitis
After esophagitis
Figure 2 Effects of acute oesophagitis on proximal extent and
velocity. (A) The proximal extent of different viscous solu-
tions was higher during oesophagitis with the more viscous
solution (*1% MC: P < 0.05, vs before oesophagitis).
(B) Velocity of proximal extent was slightly faster following
acute oesophagitis (NS).
Volume 19, Number 6, June 2007Oesophagitis and proximal reflux
? 2007 The Authors
Journal compilation ? 2007 Blackwell Publishing Ltd
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