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Effects of omeprazole therapy on pathogenetic mechanisms of gastroesophageal reflux in children with refractory esophagitis
April 1995
• IN VIVO TRAFFICKING OF NASCENT H,K-ATPASE IN THE RABBIT PARIETAL CELL. J.M. Crothers, Jr., D.-C. Chow, J.G. Forte Dept. of Molecular & Cell Biology, Univ. of California, Berkeley, CA 35S-methionine (35S-met) incorporation in vivo and density gradient separation of gastric mucosal homogenate into four distinct subcellular membrane pools were used to determine a time course for trafficking of newly synthesized H,K-ATPase from ER to mature tubulovesicles. Cimetidine-treated rabbits were injected with 35S-met i.v. and stomachs were taken 15-90 min later. Microsomal fractions from gastric mucosal homogenates were Subfractionated on continuous sucrose gradients, then analyzed by SDS-PAGE, Western blot, and autoradiography. Within 15 min of 35S=met injection, labeled H,K-ATPase c~subunit was recovered mainly in a peak centered at ~1.13-1.14 g/cc. This peak coincided with the distribution of the high-mannose precursor of the mature 13-subunit, and, together with early 35S-labeling of c~-subunit, indicates localization in the ER. A second peak of labeled c~-subunit, at ~1.09-1.10 g/cc and probably Golgi, emerged sharply from the ER peak by 22 min and was dominant by 30 rain. (Galactosyl transferase activity was recovered in this region, as a shoulder on a larger, denser peak that may be chief cell Golgi.) ER and "Golgi" pools are each estimated to contain <1% of total H,K-ATPase. By 90 rain, labeled c~-subunit was found mostly in a peak at -1.06-1.07 g/cc, matching the major peak of c~subunit seen by immunoblot and protein stain (a peak previously characterized as mature tubulovesicles and containing up to 75% of total H,KATPase). The 90-rain label distribution had a small secondary peak at ~1.11-1.12 g/cc, where total H,K-ATPase shows a more prominent secondary peak that was previously dubbed "senescent" and may be from older parietal cells with low levels of H,K-ATPase synthesis. Thus, a vectorial flow of new H,K-ATPase through distinct subcellular compartments can be elucidated in vivo. A time of <90 min from translation to a mature, fully modified, pool contrasts with 2 - 3 days for differentiation of parietal ceils from stem cells and several months for the life span of the cell, and is relevant to understanding 1) normal turnover of the H,KATPase, 2) altered turnover proposed to occur with various pharmacological treatments, and 3) recovery of H,K-ATPase activity after covalent inactivation by the direct proton-pump inhibitors. (Supported by NIH grant DK 38972)
• EFFECTS OF VERY LOW DOSES OF ASPIRIN (ASA) ON GASTRIC, DUODENAL & RECTAL PROSTAGLANDINSOPGs) & MUCOSAL INJURY. B Crver. G Luk, M Feldman,. VAMC & LIT SW Med Ctr, Dallas TX Long term, low-dose oral ASA prevents cardiovascular diseases. However, low dose ASA (30 to 325rag/day x 1 week) reduces gastric juice PGs (Ann Intern Med 1994;120:184-89). The long term effects of v_.f~ low ASA doses on the GI tract are unknown. PURPOSE: To evaluate long term effects of ~ low daily ASA doses on gastric, duodenal and rectal mncosal PGs in humans and to relate these effects to mucosal damage assessed by endoscopy (EGD). METHODS: In a doable-blinded, randomized fashion, 29 healthy humans were administered 10rag (n = 8), 81mg (n = 11), or 325mg (n = 10) of ASA p.o. daily for 90 days (d). Prior to ASA, subjects underwent EGD and proctoscopy with biopsies for assessment of gastrie (body & antrum), duodenal (bulb & postbulbar) and rectal mucosal PGs and injury scores (0-5 point scale). After 45 and 90 d of ASA, subjects underwent repeat EGD & proctoscopy (90 d only). PGE2 and PGF~ were quantitated by radioimmunoassay.RESULTS (*p < 0.05 vs. baseline): ASA DOSE % OF BASELINE PGE+PGF (mean + SE) m~ x days G.BODY ANTRUM BULB POSTBULB RECTUM 10x45d 39+ 8%* 57-t-18%* 77_.+22% 105+18% ........ 10 x 90d 30__. 5%* 265: 5%* 875:17% 1554-25% 1174-30% 81 x 45d 294- 5%* 314- 7%* 374- 5%* 27-1- 6%* . . . . . . . . . 81x 90d 454-12%* 294- 6%* 564-11%* 515:24%* 894-12% 325x45d 44-+12%* 334- 8%* 51-1-10%* 28± 7%* . . . . . . . . . . 325xg0d 564-20%* 41__.15%* 644-25% 49_+14%* 62+14%* CHANGE IN INJURY SCORE FROM BASELINE (mean) m~, x days G.BODY ANTRUM BULB POSTBULB RECTUM 10 x 45d +0.1 + 1.5" +0.3 0.0 ............ 10 x 90d +0.2 +0.3 +0.3 +0.1 0.0 81 x 45d + 1.0. +0.8* 0.0 0.0 .......... 81 x 90d +0.6* +0.8* +0.1 0.0 0.0 325 x 45d +0.5* + 1.2" +0.3* 0.0 ........... 325 x 90d +0.6 +1.9" +0.7 +0.1 0.0 Gastric ulcer(GU) was seen in one subject at 45d (10rag) and in 2 others at 90d (325mg), one of whom had 2 GUs. CONCLUSIONS: Even 10rag ASA/day significantly lowers gastric PGs & causes significant gastric injury, including GU. The duodenum is less sensitive to PG inhibition and damage by ASA, and, the colon is relatively insensitive. Our findings explain ASA's predominant gastric toxicity in the human GI tract and question the safety of even very low-dose ASA.
Esophageal, Gastric, and Duodenal Disorders A77
• EFFECT OF ERADICATION OF HELICOBACTER PYLORI (Hp) ON GASTRIC ACID SECRETION IN HEALTHY HUMANS. B (~ryer, E Lee, M Feldman, Departments of Medicine & Pathology, Dallas VA Med Ctr & UT Southwestern Med Ctr, Dallas TX
Hp gastritis is one of the commonest infections of humans. However, the effect of Hp infection on gastric secretion is uncertain. PURPOSE: To evaluate the effect of lip eradication on gastric acid secretion in Hp-infected humans with no history of ulcer disease. METHODS: In 30 asymptomatic volunteers (14 male, ages 28 to 89 yrs, 10 Caucasian/20 non-Caucasian) who all were Hp+ by serology, basal & peak acid outputs (BAO,PAO) were measured, the latter following subcutaneous injection of 6 izg/kg pcntagastrin. Immediately following the gastric secretory study, gastric body and antral biopsies were obtained with fluoroscopic assistance by passing a forceps through the nasogastrie tube. Subjects then took Pepto-BismolR(2 tabs QID), metronidazole (250rag TID) & tetracycline (500 mg QID) x 14 days. One and three months following completion of antibiotics, subjects had repeat gastric acid studies and gastric biopsies. Hp eradication was defined as disappearance of Hp and resolution of acute inflammation on one and three month mucosal biopsies. RESULTS(mean 5: se): Hp Not Eradicated Hp Eradicated (n=12) (n=lS~ BAO (mmol/hr) Baseline 3.74-1.5 3.6±0.9 1 Mo after Rx 3.05:1.1 4.74-1.0 3 Mo after Rx 4.54-2.1 3.84-0.9 PAO (mmot/hr) Baseline 28.24-3.9 24,04-3.7 1 Mo after Rx 30.44-4.8 24.94-1.9 3 Mo after Rx 29.04-4.6 25.4_+3.7 Age (yrs) 384-2 54+4* % Caucasian 0% 56%** *p <0.05 vs. Hp not eradicated by group t test **p < 0.05 vs. Hp not eradicated by chi square test CONCLUSIONS: In healthy subjects, eradication of Hp does not significantly change gastric acid secretion during the first three months after Hp eradication: Younger age and non-Caucasian racial status may be associated with a lower likelihood of Hp eradication with this triple therapy regimen.
• EFFECTS OF OMEPRAZOLE
THERAPY ON
PATHOGENETIC
MECHANISMS OF GASTROESOPHAGEAL REFLUX IN CHILDREN WITH REFRACTORY ESOPHAGIT1S. S.Cucchiara, R.Minella, MT.
Franco, M.Emiliano, Dept. Pediatrics, University of Naples, Italy There are no reports on the effects of antisecretory therapy on pathogenetic mechanisms of gastroesophageal reflux (GER) in children with refractory esophagitis, that is unresponsive to H2 receptor antagonists. Simultaneous recordings of lower esophageal sphincter (LES) motility and distal esophageal pH were done in 22 children (range age: 19 months-12 yrs) with refractory esophagitis, before and after an 8-week therapeutic course with omeprazole (40-60 mg/l.73 m2 S.A./day). Recordings were performed with a manometric sleeve probe 1 hr before and 1 hr after feeding a pear yogurtlt with 5% polycose (300 ec/1.73 nu SA.). Two main mechanisms of GER were identified: transient relaxation of LES (TLESR) and LES pressure drift to low manometric levels. We also measured gastric emptying (GE) time (rain.) of a semisolid meal by ultrasonography and evaluated esophageal mucosa by endoscopy and histology (score 0--,8, basal zone hyperplasia, papillae elongated, nentrophil-eosinophil infiltration, mucosal slough). Results (mean+-SD): basal fasting and fed rate (N./hr) of TLESRs (3.6__. 1.06, 6.9+_1.7, respectively) and LES tone drifts (2.0+_0.8, 3.5 + 1.3, respectively) as well as GE time (197+_31) were higher than in a population of t0 control children (range age: 22 months-10 yrs) affected by functional GER without esophagitls (TLESRs: 1.4+_0.6, 2.4_+0.5; LES tone drifts: 0.7+_0.6, 1.6+_0.5; p<0.01) (GE; 157+_15, p<0.01). At the end of the therapeutic course, esophagitis score decreased from 7.0-1-1.3 to 2.09_+ 1.5 (p<0.01); however, the rate of TLESRs (fasting: 3.04__. 1.5; fed: 5.9+-2.5) and of LES pressure drifts (fasting: 1.9+- 1.04; fed: 2.9_+ 1.6) as well as gastric emptying time (190+-27.6) did not statistically differ from baseline values. After stopping omeprazole, 16 patients were significantly symptomatic and underwent a new investigative and therapeutic program. Conclusions: in children with severe GER esophagitis, omeprazole treatment does not affect esophageal motor variables playing a role in the pathogenesis of GER, in spite of healed or improved esophagitis; an increased rate of both TLESRs and LES tone dritts represents a primary motor disorder; a high frequency of these motor defects and persistence ofgastroparesis are implicated in the refractoriness of GER disease.
• IN VIVO TRAFFICKING OF NASCENT H,K-ATPASE IN THE RABBIT PARIETAL CELL. J.M. Crothers, Jr., D.-C. Chow, J.G. Forte Dept. of Molecular & Cell Biology, Univ. of California, Berkeley, CA 35S-methionine (35S-met) incorporation in vivo and density gradient separation of gastric mucosal homogenate into four distinct subcellular membrane pools were used to determine a time course for trafficking of newly synthesized H,K-ATPase from ER to mature tubulovesicles. Cimetidine-treated rabbits were injected with 35S-met i.v. and stomachs were taken 15-90 min later. Microsomal fractions from gastric mucosal homogenates were Subfractionated on continuous sucrose gradients, then analyzed by SDS-PAGE, Western blot, and autoradiography. Within 15 min of 35S=met injection, labeled H,K-ATPase c~subunit was recovered mainly in a peak centered at ~1.13-1.14 g/cc. This peak coincided with the distribution of the high-mannose precursor of the mature 13-subunit, and, together with early 35S-labeling of c~-subunit, indicates localization in the ER. A second peak of labeled c~-subunit, at ~1.09-1.10 g/cc and probably Golgi, emerged sharply from the ER peak by 22 min and was dominant by 30 rain. (Galactosyl transferase activity was recovered in this region, as a shoulder on a larger, denser peak that may be chief cell Golgi.) ER and "Golgi" pools are each estimated to contain <1% of total H,K-ATPase. By 90 rain, labeled c~-subunit was found mostly in a peak at -1.06-1.07 g/cc, matching the major peak of c~subunit seen by immunoblot and protein stain (a peak previously characterized as mature tubulovesicles and containing up to 75% of total H,KATPase). The 90-rain label distribution had a small secondary peak at ~1.11-1.12 g/cc, where total H,K-ATPase shows a more prominent secondary peak that was previously dubbed "senescent" and may be from older parietal cells with low levels of H,K-ATPase synthesis. Thus, a vectorial flow of new H,K-ATPase through distinct subcellular compartments can be elucidated in vivo. A time of <90 min from translation to a mature, fully modified, pool contrasts with 2 - 3 days for differentiation of parietal ceils from stem cells and several months for the life span of the cell, and is relevant to understanding 1) normal turnover of the H,KATPase, 2) altered turnover proposed to occur with various pharmacological treatments, and 3) recovery of H,K-ATPase activity after covalent inactivation by the direct proton-pump inhibitors. (Supported by NIH grant DK 38972)
• EFFECTS OF VERY LOW DOSES OF ASPIRIN (ASA) ON GASTRIC, DUODENAL & RECTAL PROSTAGLANDINSOPGs) & MUCOSAL INJURY. B Crver. G Luk, M Feldman,. VAMC & LIT SW Med Ctr, Dallas TX Long term, low-dose oral ASA prevents cardiovascular diseases. However, low dose ASA (30 to 325rag/day x 1 week) reduces gastric juice PGs (Ann Intern Med 1994;120:184-89). The long term effects of v_.f~ low ASA doses on the GI tract are unknown. PURPOSE: To evaluate long term effects of ~ low daily ASA doses on gastric, duodenal and rectal mncosal PGs in humans and to relate these effects to mucosal damage assessed by endoscopy (EGD). METHODS: In a doable-blinded, randomized fashion, 29 healthy humans were administered 10rag (n = 8), 81mg (n = 11), or 325mg (n = 10) of ASA p.o. daily for 90 days (d). Prior to ASA, subjects underwent EGD and proctoscopy with biopsies for assessment of gastrie (body & antrum), duodenal (bulb & postbulbar) and rectal mucosal PGs and injury scores (0-5 point scale). After 45 and 90 d of ASA, subjects underwent repeat EGD & proctoscopy (90 d only). PGE2 and PGF~ were quantitated by radioimmunoassay.RESULTS (*p < 0.05 vs. baseline): ASA DOSE % OF BASELINE PGE+PGF (mean + SE) m~ x days G.BODY ANTRUM BULB POSTBULB RECTUM 10x45d 39+ 8%* 57-t-18%* 77_.+22% 105+18% ........ 10 x 90d 30__. 5%* 265: 5%* 875:17% 1554-25% 1174-30% 81 x 45d 294- 5%* 314- 7%* 374- 5%* 27-1- 6%* . . . . . . . . . 81x 90d 454-12%* 294- 6%* 564-11%* 515:24%* 894-12% 325x45d 44-+12%* 334- 8%* 51-1-10%* 28± 7%* . . . . . . . . . . 325xg0d 564-20%* 41__.15%* 644-25% 49_+14%* 62+14%* CHANGE IN INJURY SCORE FROM BASELINE (mean) m~, x days G.BODY ANTRUM BULB POSTBULB RECTUM 10 x 45d +0.1 + 1.5" +0.3 0.0 ............ 10 x 90d +0.2 +0.3 +0.3 +0.1 0.0 81 x 45d + 1.0. +0.8* 0.0 0.0 .......... 81 x 90d +0.6* +0.8* +0.1 0.0 0.0 325 x 45d +0.5* + 1.2" +0.3* 0.0 ........... 325 x 90d +0.6 +1.9" +0.7 +0.1 0.0 Gastric ulcer(GU) was seen in one subject at 45d (10rag) and in 2 others at 90d (325mg), one of whom had 2 GUs. CONCLUSIONS: Even 10rag ASA/day significantly lowers gastric PGs & causes significant gastric injury, including GU. The duodenum is less sensitive to PG inhibition and damage by ASA, and, the colon is relatively insensitive. Our findings explain ASA's predominant gastric toxicity in the human GI tract and question the safety of even very low-dose ASA.
Esophageal, Gastric, and Duodenal Disorders A77
• EFFECT OF ERADICATION OF HELICOBACTER PYLORI (Hp) ON GASTRIC ACID SECRETION IN HEALTHY HUMANS. B (~ryer, E Lee, M Feldman, Departments of Medicine & Pathology, Dallas VA Med Ctr & UT Southwestern Med Ctr, Dallas TX
Hp gastritis is one of the commonest infections of humans. However, the effect of Hp infection on gastric secretion is uncertain. PURPOSE: To evaluate the effect of lip eradication on gastric acid secretion in Hp-infected humans with no history of ulcer disease. METHODS: In 30 asymptomatic volunteers (14 male, ages 28 to 89 yrs, 10 Caucasian/20 non-Caucasian) who all were Hp+ by serology, basal & peak acid outputs (BAO,PAO) were measured, the latter following subcutaneous injection of 6 izg/kg pcntagastrin. Immediately following the gastric secretory study, gastric body and antral biopsies were obtained with fluoroscopic assistance by passing a forceps through the nasogastrie tube. Subjects then took Pepto-BismolR(2 tabs QID), metronidazole (250rag TID) & tetracycline (500 mg QID) x 14 days. One and three months following completion of antibiotics, subjects had repeat gastric acid studies and gastric biopsies. Hp eradication was defined as disappearance of Hp and resolution of acute inflammation on one and three month mucosal biopsies. RESULTS(mean 5: se): Hp Not Eradicated Hp Eradicated (n=12) (n=lS~ BAO (mmol/hr) Baseline 3.74-1.5 3.6±0.9 1 Mo after Rx 3.05:1.1 4.74-1.0 3 Mo after Rx 4.54-2.1 3.84-0.9 PAO (mmot/hr) Baseline 28.24-3.9 24,04-3.7 1 Mo after Rx 30.44-4.8 24.94-1.9 3 Mo after Rx 29.04-4.6 25.4_+3.7 Age (yrs) 384-2 54+4* % Caucasian 0% 56%** *p <0.05 vs. Hp not eradicated by group t test **p < 0.05 vs. Hp not eradicated by chi square test CONCLUSIONS: In healthy subjects, eradication of Hp does not significantly change gastric acid secretion during the first three months after Hp eradication: Younger age and non-Caucasian racial status may be associated with a lower likelihood of Hp eradication with this triple therapy regimen.
• EFFECTS OF OMEPRAZOLE
THERAPY ON
PATHOGENETIC
MECHANISMS OF GASTROESOPHAGEAL REFLUX IN CHILDREN WITH REFRACTORY ESOPHAGIT1S. S.Cucchiara, R.Minella, MT.
Franco, M.Emiliano, Dept. Pediatrics, University of Naples, Italy There are no reports on the effects of antisecretory therapy on pathogenetic mechanisms of gastroesophageal reflux (GER) in children with refractory esophagitis, that is unresponsive to H2 receptor antagonists. Simultaneous recordings of lower esophageal sphincter (LES) motility and distal esophageal pH were done in 22 children (range age: 19 months-12 yrs) with refractory esophagitis, before and after an 8-week therapeutic course with omeprazole (40-60 mg/l.73 m2 S.A./day). Recordings were performed with a manometric sleeve probe 1 hr before and 1 hr after feeding a pear yogurtlt with 5% polycose (300 ec/1.73 nu SA.). Two main mechanisms of GER were identified: transient relaxation of LES (TLESR) and LES pressure drift to low manometric levels. We also measured gastric emptying (GE) time (rain.) of a semisolid meal by ultrasonography and evaluated esophageal mucosa by endoscopy and histology (score 0--,8, basal zone hyperplasia, papillae elongated, nentrophil-eosinophil infiltration, mucosal slough). Results (mean+-SD): basal fasting and fed rate (N./hr) of TLESRs (3.6__. 1.06, 6.9+_1.7, respectively) and LES tone drifts (2.0+_0.8, 3.5 + 1.3, respectively) as well as GE time (197+_31) were higher than in a population of t0 control children (range age: 22 months-10 yrs) affected by functional GER without esophagitls (TLESRs: 1.4+_0.6, 2.4_+0.5; LES tone drifts: 0.7+_0.6, 1.6+_0.5; p<0.01) (GE; 157+_15, p<0.01). At the end of the therapeutic course, esophagitis score decreased from 7.0-1-1.3 to 2.09_+ 1.5 (p<0.01); however, the rate of TLESRs (fasting: 3.04__. 1.5; fed: 5.9+-2.5) and of LES pressure drifts (fasting: 1.9+- 1.04; fed: 2.9_+ 1.6) as well as gastric emptying time (190+-27.6) did not statistically differ from baseline values. After stopping omeprazole, 16 patients were significantly symptomatic and underwent a new investigative and therapeutic program. Conclusions: in children with severe GER esophagitis, omeprazole treatment does not affect esophageal motor variables playing a role in the pathogenesis of GER, in spite of healed or improved esophagitis; an increased rate of both TLESRs and LES tone dritts represents a primary motor disorder; a high frequency of these motor defects and persistence ofgastroparesis are implicated in the refractoriness of GER disease.