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Zonal negative feedback regulation of active ileal bile acid transport in guinea pig
April 1 9 9 5
• EFFECTS OF OXYGEN RADICALS AND RADICAL SCAVENGING SYSTEMS ON THE OPOSSUM LOWER ESOPHAGEAL SPHINCTER (LES) L.S. Leichus, R. Thomas, and J.L. Conklin; University of Iowa College of Medicine, Iowa City, Iowa and V.A. Medical Center, Iowa City, Iowa 52242 B a e k e r o u n d : Nitric oxide (NO) from esophageal nerves mediates the timing of esophageal peristalsis and relaxation of the LES. Superoxide radical (02'-) generated during normal metabolism or in inflammatory states inactivates NO by converting it to peroxynitrite. Superoxide is cleared in biological systems by superoxide dismutase (SOD) and catalase (CAT) which convert O2-- to hydrogen peroxide (H202) and then H 2 0 and 02. These 0 2 ' - scavenging enzymes are present in myemeric neurons of the opossum esophagus. Inhibiting their activity alters esophageal motor function in a way analogous to antagonists of NO synthesis. Hypothesis: O2"" and the 02"- scavenging system modulate lower esophageal sphincter tone and relaxation. M e t h o d s : Transverse strips of lower esophageal sphincter muscle were stimulated by an electrical field (EFS) (4 sec. trains of 3Or, 1 msec pulses at 2Hz). Diethyldithiocarbamite (DDC) was used to inhibit SOD. Xanthine IX) and xanthine oxidase (XO) were used to generate 02'-. The effects of H 2 0 2 were also observed. Results: X (0.1 mM) and XO (3 x 10-3 U/ml) or DDC (3 Mm) alone had no effect on the resting tone or relaxation elicited during EFS. However, X and XO (X/XO) when in the presence of DDC elicited a 29% reduction in relaxation and a 44% increase in resting tone, P< 0.01. H 2 0 2 (0.5%) caused a similar response with a 24% reduction in relaxation and a 37% increase in resting tone, P < 0.05. The addition of copper/zinc SOD to the tissue bath did not affect the resting tone or relaxation of the LES. In the presence of SOD, DDC and nearly three times as much X/XO was needed to produce the effects seen in the absence of SOD. Carbachol, which increases LES tone, does not decrease the percent relaxation of the LES, indicating that the observed decrease in LES relaxation is not simply the result of changing LES tone. S u m m a r y : DDC and X/XO together and H 2 0 2 alone inhibit relaxation and increased resting tone in the LES. SOD antagonizes these effects of DDC and X/XO. C o n c l u s i o n : These studies support the hypothesis that 0 2 - and the 02" scavenging system can modulate neuromuscular function of the lower esophageal sphincter. The data are consistent with the hypothesis that 0 2 ' - acts by inactivating NO, and suggest that these antioxidant enzyme systems may play a role in the maintenance of LES function.
8ASTRICELECTRICALAYTHYHRECOROEgBY CUTANEOUSELECTROGASTROURAPHY(EGG) [N ASYMPTOHATIC H, PYLOR!POSITIVE (+) and NEGATIVEI-I SUBJECTS,H, Levendnglu, Y, Zhang, The Brookdale Hospital Medical Center and SUNYHealth Science Center at Brooklyn, Brooklyn, Hen York, It
is not known mhether basic electrical rythyu of the stomach changes in gastric
inflammation. H, Pylori is a knonn cause of gastritis, In a study involving lg~ H. Pylori (+1 and 6 H. Pylori (-) asyaptoaatic subjects, ne recorded gastric electrical rythya by cutaneous EGG. The EGGrecordings uure uadu on fasting, folloeing ~OOccof
eater distension of the stomach ingestion of liquid teal (natron 1,O) and isocaloric solid teal (500 caloric) on different days, In healthy subjects bradygastria is recorded as 28g, normal opt activity Sgg and tachygastria as 2IX of the rythyu. In fasting H. Pylori I+) and (-) subjects shooed similar frequency of bradygastria, noreal 3cpu rythya and tachygastria eith similar meandominant rythy| and pumer. In H, Pylori (-t subjects water distension and liquid uasl caused a significant decrease in bradygaetria and increase tachygastria uhen compared to fasting. This chanqe nan not seen in H. Pylori (+) suhiecte. In solid meal phase, there has significant difference in electircal rythyu betweenthe tee groups; lees bradygautria and more tachygastria asre observed in H. Pylori (+) subjects. In solid meal studies, H. Pylori I-I negative subjects had significantly more bradygastric rythye ehen coupared to H. Pylori (+) subjects. There has statistically significant instability in dominant
peter folio.mugwater distension, liquid and solid meal betneen H. Pylori (+l and (-I subjects. He summarize that t. Hradygastria and tachygastria are comon findinqs in healthy subjects. 2. Bradygastria increased follo#ing solid meal, tachygastria fo]-
1oeing liquid anal in healthy subjects nith0ut a significant change in normal 3cpm rythye.
Thesechanges do not occur in H. Pylori (+) subjects. 3. Electrical rythyu
is different following liquid and solid real in healthy subjects while it is similar in H. Pylori (+1 subjects. 6. Voluue~ liquid and solid nature of the gastric content but not the caloric value is related to the rythya recorded. 5. instability of dominant poeer is expected H. Pylori (+) subjects. In conclusion t in health bradygastria and tachygastria may be an electrical aeconoadation of stomach to solid and liquid meal respectively. This acconoadation is lost in H. Pylori (+1 subjects. Observed tachygastria in H. Pylori (+1 subjects follouieg solid seal aay be an indicator of antral hypoeotility related to antral inflammation. Instability of dominant pouer may be related to the effect of aniral inflammation on smooth muscle contractility. Changeo in electrical rythye may not manifest itself on symptomssince, all of our subjects uere asyuptoeatic.
Motility and Nerve-Gut Interactions
A637
WHICH SEXUAL/PHYSICAL ABUSE FACTORS AFFECT HEALTH STATUS? J.Leserman, Z.Li, D.A.Drossman, T.Toomey, G.Nachman, L.Glogau, Y.Hu. Depts. of Psychiatry and Medicine, Div. of Dig. Dis., Univ. of N.C., Chapel Hill. There is a growing literature linking sexual and physical abuse history to poor health outcome among patients with GI disorders. To follow-up our first observations of this phenomenon (Ann Int Med 1990; 113: 828-33), we report an interview based study among female patients in a GI clinic which assesses the relative importance of severity of sexual (e.g. penetration, attempt) and physical (e.g. life threat) abuse. We interviewed 239 female patients in a referral GI clinic (mean age 39 years, mean education 14 years, 84% white, 38.5% functional and 61.5% organic diagnosis). The health status measures included: Pain (0-100 Visual Analog Scale, 14 day mean), # medical symptoms, # days in bed/3 me., # lifetime surgeries, psychologicaldistress (GSI of SCL-90-R), and daily function (SIP-Overall). All abuse variables were dummy coded for the most severe sexual and physical abuse patients had. We found that 55% had a sexual abuse history (14% attempted abuse, 16% touch experience, and 25% penetration), 48% had physical abuse history (20% hit, 28% life threat), and 67% had experienced either sexual or physical abuse. Using ANCOVA controlling for age, education, race and diagnosis (functional vs. organic), we found that patients with histories of sexual penetration, life-threat physical abuse and, to a lesser extent, sexual abuse involving touch were significantlydifferent from those with no abuse on health status. ........................................................... Abuse PAIN #SYMPTOMS BEDDAYS #SURG SCL90 ...........................................................
SIP
Sexual:
None Attempt Touch Penetration p (sexual)
25 25 23 36* .008
ll Ii 14" 14" .003
22 28 33* .005
12 22 14" .02
6.4 4.8 6.2 14.5" .001
3.6 4.1 3.5 5.8" .004
0.67 0,62 0.92* 1.03" .0004
7.3 6.4 10.2 14.0" .0002
5.9 7.9 i0.0 .21
4.1 3.4 8.4" .02
0.73 0.78 0.92 .12
8.2 8.7 12.5" .05
23%
17%
Physical:
None Hit Life-threat p (physical) Increment
R2
13%
15%
12%
11%
Note: Least square ~eans adjusted for race, age, education diagnosisusing ANCOVA; IncrementalR equals percent variance expla ned by abuse variables * different from none at <0.05 level
To conclude: 1) sexual and physical abuse are extremely common among patients in referral G1 practice; and 2) sexual abuse involving "contact", especially penetration, and physical abuse involving life threat have a substantial effect on health status.
ZONAL NEGATIVE F E E D B A C K REGULATION OF ACTIVE ILEAL BILE ACID TRANSPORT IN GUINEA PIG. J. Lillienau. Cell Biology Research Dep., Lund University Hospital, S-221 85 Lund, Sweden. Background: Recent results suggest that active ileal bile acid transport in rodent is regulated by negative feedback (Gastroenterology 1993;104:3846). Several different mechanisms for this regulation are possible. It was hypothesized that it is a zonal concentration dependent mechanism, similar to that seen for regulation of bile acid biosynthesis in the liver. Methods: Guinea pigs were fed regular chow or chow enriched with either 0,4% cholic acid (decreases bile acid transport) or 5% cholestyramine (increases bile acid transport) for six days. After laparotomy -65 cm (-2/3) of the distal small intestine was rinsed while blood circulation was maintained. The rinsed intestine was excised and placed in a 37°C bath and 8 mL of a 24-Ct4-cholyltaurine solution was infused into the intestine. After 10 tin. of incubation the intestine was thoroughly rinsed, cut in 3 cm segments, weighed, solubilized and radioactivity determined in each segment. Results: The total cholyltaurine uptake in the incubated intestine was related to animal weight. Total cholyltaurine uptake in normal animals was 1,6:E0,2 pmol/min*kg (MV+SD). Cholic acid feeding decreased uptake to 0,7±0,1 pmol/min*kg, and cholestyramine feeding increased uptake to 2,6±0,3 p.mol/min,kg, + Normalchow ~2 5 (p<0.01 between all val+ Cholieacid e, ~2,0 ues). The bile acid uptake o v along the intestinal axis is .~ oi,5 ,~ ~ presented in the figure to ~ .~l,0 the left. ~0,5 Conclusions: These rep'S,0,0 suits indicate that up~ 0 regulation of active ileal 20 40 60 bile acid absorption is Distance proximal of cecum (cm) controlled by a mechanism which recruits more proximal ileal enterocytes, without increasing the absorption per enterocyte. On the other hand, down-regulation shit, s the absorption towards more distal enterocytes, as well as decreases the absorption per enterocyte.
• EFFECTS OF OXYGEN RADICALS AND RADICAL SCAVENGING SYSTEMS ON THE OPOSSUM LOWER ESOPHAGEAL SPHINCTER (LES) L.S. Leichus, R. Thomas, and J.L. Conklin; University of Iowa College of Medicine, Iowa City, Iowa and V.A. Medical Center, Iowa City, Iowa 52242 B a e k e r o u n d : Nitric oxide (NO) from esophageal nerves mediates the timing of esophageal peristalsis and relaxation of the LES. Superoxide radical (02'-) generated during normal metabolism or in inflammatory states inactivates NO by converting it to peroxynitrite. Superoxide is cleared in biological systems by superoxide dismutase (SOD) and catalase (CAT) which convert O2-- to hydrogen peroxide (H202) and then H 2 0 and 02. These 0 2 ' - scavenging enzymes are present in myemeric neurons of the opossum esophagus. Inhibiting their activity alters esophageal motor function in a way analogous to antagonists of NO synthesis. Hypothesis: O2"" and the 02"- scavenging system modulate lower esophageal sphincter tone and relaxation. M e t h o d s : Transverse strips of lower esophageal sphincter muscle were stimulated by an electrical field (EFS) (4 sec. trains of 3Or, 1 msec pulses at 2Hz). Diethyldithiocarbamite (DDC) was used to inhibit SOD. Xanthine IX) and xanthine oxidase (XO) were used to generate 02'-. The effects of H 2 0 2 were also observed. Results: X (0.1 mM) and XO (3 x 10-3 U/ml) or DDC (3 Mm) alone had no effect on the resting tone or relaxation elicited during EFS. However, X and XO (X/XO) when in the presence of DDC elicited a 29% reduction in relaxation and a 44% increase in resting tone, P< 0.01. H 2 0 2 (0.5%) caused a similar response with a 24% reduction in relaxation and a 37% increase in resting tone, P < 0.05. The addition of copper/zinc SOD to the tissue bath did not affect the resting tone or relaxation of the LES. In the presence of SOD, DDC and nearly three times as much X/XO was needed to produce the effects seen in the absence of SOD. Carbachol, which increases LES tone, does not decrease the percent relaxation of the LES, indicating that the observed decrease in LES relaxation is not simply the result of changing LES tone. S u m m a r y : DDC and X/XO together and H 2 0 2 alone inhibit relaxation and increased resting tone in the LES. SOD antagonizes these effects of DDC and X/XO. C o n c l u s i o n : These studies support the hypothesis that 0 2 - and the 02" scavenging system can modulate neuromuscular function of the lower esophageal sphincter. The data are consistent with the hypothesis that 0 2 ' - acts by inactivating NO, and suggest that these antioxidant enzyme systems may play a role in the maintenance of LES function.
8ASTRICELECTRICALAYTHYHRECOROEgBY CUTANEOUSELECTROGASTROURAPHY(EGG) [N ASYMPTOHATIC H, PYLOR!POSITIVE (+) and NEGATIVEI-I SUBJECTS,H, Levendnglu, Y, Zhang, The Brookdale Hospital Medical Center and SUNYHealth Science Center at Brooklyn, Brooklyn, Hen York, It
is not known mhether basic electrical rythyu of the stomach changes in gastric
inflammation. H, Pylori is a knonn cause of gastritis, In a study involving lg~ H. Pylori (+1 and 6 H. Pylori (-) asyaptoaatic subjects, ne recorded gastric electrical rythya by cutaneous EGG. The EGGrecordings uure uadu on fasting, folloeing ~OOccof
eater distension of the stomach ingestion of liquid teal (natron 1,O) and isocaloric solid teal (500 caloric) on different days, In healthy subjects bradygastria is recorded as 28g, normal opt activity Sgg and tachygastria as 2IX of the rythyu. In fasting H. Pylori I+) and (-) subjects shooed similar frequency of bradygastria, noreal 3cpu rythya and tachygastria eith similar meandominant rythy| and pumer. In H, Pylori (-t subjects water distension and liquid uasl caused a significant decrease in bradygaetria and increase tachygastria uhen compared to fasting. This chanqe nan not seen in H. Pylori (+) suhiecte. In solid meal phase, there has significant difference in electircal rythyu betweenthe tee groups; lees bradygautria and more tachygastria asre observed in H. Pylori (+) subjects. In solid meal studies, H. Pylori I-I negative subjects had significantly more bradygastric rythye ehen coupared to H. Pylori (+) subjects. There has statistically significant instability in dominant
peter folio.mugwater distension, liquid and solid meal betneen H. Pylori (+l and (-I subjects. He summarize that t. Hradygastria and tachygastria are comon findinqs in healthy subjects. 2. Bradygastria increased follo#ing solid meal, tachygastria fo]-
1oeing liquid anal in healthy subjects nith0ut a significant change in normal 3cpm rythye.
Thesechanges do not occur in H. Pylori (+) subjects. 3. Electrical rythyu
is different following liquid and solid real in healthy subjects while it is similar in H. Pylori (+1 subjects. 6. Voluue~ liquid and solid nature of the gastric content but not the caloric value is related to the rythya recorded. 5. instability of dominant poeer is expected H. Pylori (+) subjects. In conclusion t in health bradygastria and tachygastria may be an electrical aeconoadation of stomach to solid and liquid meal respectively. This acconoadation is lost in H. Pylori (+1 subjects. Observed tachygastria in H. Pylori (+1 subjects follouieg solid seal aay be an indicator of antral hypoeotility related to antral inflammation. Instability of dominant pouer may be related to the effect of aniral inflammation on smooth muscle contractility. Changeo in electrical rythye may not manifest itself on symptomssince, all of our subjects uere asyuptoeatic.
Motility and Nerve-Gut Interactions
A637
WHICH SEXUAL/PHYSICAL ABUSE FACTORS AFFECT HEALTH STATUS? J.Leserman, Z.Li, D.A.Drossman, T.Toomey, G.Nachman, L.Glogau, Y.Hu. Depts. of Psychiatry and Medicine, Div. of Dig. Dis., Univ. of N.C., Chapel Hill. There is a growing literature linking sexual and physical abuse history to poor health outcome among patients with GI disorders. To follow-up our first observations of this phenomenon (Ann Int Med 1990; 113: 828-33), we report an interview based study among female patients in a GI clinic which assesses the relative importance of severity of sexual (e.g. penetration, attempt) and physical (e.g. life threat) abuse. We interviewed 239 female patients in a referral GI clinic (mean age 39 years, mean education 14 years, 84% white, 38.5% functional and 61.5% organic diagnosis). The health status measures included: Pain (0-100 Visual Analog Scale, 14 day mean), # medical symptoms, # days in bed/3 me., # lifetime surgeries, psychologicaldistress (GSI of SCL-90-R), and daily function (SIP-Overall). All abuse variables were dummy coded for the most severe sexual and physical abuse patients had. We found that 55% had a sexual abuse history (14% attempted abuse, 16% touch experience, and 25% penetration), 48% had physical abuse history (20% hit, 28% life threat), and 67% had experienced either sexual or physical abuse. Using ANCOVA controlling for age, education, race and diagnosis (functional vs. organic), we found that patients with histories of sexual penetration, life-threat physical abuse and, to a lesser extent, sexual abuse involving touch were significantlydifferent from those with no abuse on health status. ........................................................... Abuse PAIN #SYMPTOMS BEDDAYS #SURG SCL90 ...........................................................
SIP
Sexual:
None Attempt Touch Penetration p (sexual)
25 25 23 36* .008
ll Ii 14" 14" .003
22 28 33* .005
12 22 14" .02
6.4 4.8 6.2 14.5" .001
3.6 4.1 3.5 5.8" .004
0.67 0,62 0.92* 1.03" .0004
7.3 6.4 10.2 14.0" .0002
5.9 7.9 i0.0 .21
4.1 3.4 8.4" .02
0.73 0.78 0.92 .12
8.2 8.7 12.5" .05
23%
17%
Physical:
None Hit Life-threat p (physical) Increment
R2
13%
15%
12%
11%
Note: Least square ~eans adjusted for race, age, education diagnosisusing ANCOVA; IncrementalR equals percent variance expla ned by abuse variables * different from none at <0.05 level
To conclude: 1) sexual and physical abuse are extremely common among patients in referral G1 practice; and 2) sexual abuse involving "contact", especially penetration, and physical abuse involving life threat have a substantial effect on health status.
ZONAL NEGATIVE F E E D B A C K REGULATION OF ACTIVE ILEAL BILE ACID TRANSPORT IN GUINEA PIG. J. Lillienau. Cell Biology Research Dep., Lund University Hospital, S-221 85 Lund, Sweden. Background: Recent results suggest that active ileal bile acid transport in rodent is regulated by negative feedback (Gastroenterology 1993;104:3846). Several different mechanisms for this regulation are possible. It was hypothesized that it is a zonal concentration dependent mechanism, similar to that seen for regulation of bile acid biosynthesis in the liver. Methods: Guinea pigs were fed regular chow or chow enriched with either 0,4% cholic acid (decreases bile acid transport) or 5% cholestyramine (increases bile acid transport) for six days. After laparotomy -65 cm (-2/3) of the distal small intestine was rinsed while blood circulation was maintained. The rinsed intestine was excised and placed in a 37°C bath and 8 mL of a 24-Ct4-cholyltaurine solution was infused into the intestine. After 10 tin. of incubation the intestine was thoroughly rinsed, cut in 3 cm segments, weighed, solubilized and radioactivity determined in each segment. Results: The total cholyltaurine uptake in the incubated intestine was related to animal weight. Total cholyltaurine uptake in normal animals was 1,6:E0,2 pmol/min*kg (MV+SD). Cholic acid feeding decreased uptake to 0,7±0,1 pmol/min*kg, and cholestyramine feeding increased uptake to 2,6±0,3 p.mol/min,kg, + Normalchow ~2 5 (p<0.01 between all val+ Cholieacid e, ~2,0 ues). The bile acid uptake o v along the intestinal axis is .~ oi,5 ,~ ~ presented in the figure to ~ .~l,0 the left. ~0,5 Conclusions: These rep'S,0,0 suits indicate that up~ 0 regulation of active ileal 20 40 60 bile acid absorption is Distance proximal of cecum (cm) controlled by a mechanism which recruits more proximal ileal enterocytes, without increasing the absorption per enterocyte. On the other hand, down-regulation shit, s the absorption towards more distal enterocytes, as well as decreases the absorption per enterocyte.