- Email: [email protected]
Immunoneutralization of calcitonin gene-related peptide (CGRP) during inhibition of intestinal transit by fat
GASTROENTEROLOGYVol. 114, No. 4
A790 AGA ABSTRACTS
• G3251 EVALUATION OF GASTRIC EMPTYING BY MEASUREMENT OF PROPORTION OF INTRA-ABDOMINAL RADIOACTIVITY IN STOMACH. HC Lien. CS Chang, GH Chen, CH Kao, SC Tsai, SJ Wang. Taichung Veterans General Hospital, Taiwan, ROC. Background, Using scintigraphic techniques the rate of gastric emptying is usually calculated by quantifying the amount of radioactivity within a gastric region-of-interest and considering the time of meal completion as 100% retention. This technique has, however, significant limitations arising from subject movement and radionuclide gamma ray attenuation, which may render curvefitting difficult, particularly in patients with gastroparesis. In attempts to minimize these issues we have expressed the intragastric content as a percentage of the total abdominal radioactivity, and compare this method to the conventional one. Method. Twenty-three patients with non-ulcer dyspepsia (9 male, 14 female) consumed a mixed solid and liquid meal containing of 2 fried eggs labeled with 99mTc, 2 slices of toast and 500 ml of 5% glucose water (412kcal) in sitting position. Data were acquired at a rate of one frame every 5 minutes for 90 minutes from left anterior view. Time 0 was considered to represent the time of meal completion. The intragastric retention at 90 min (RR90), the 50% emptying time (TS0) calculated by a power exponential fit and R2 (1 - residual sum of squares/total sum of squares) represents the goodness of fit of power exponential fit were calculated using the two methods. Results were compared to an established normal range in which delayed gastric emptying was a RR90 > 68%. Data are expressed as mean -+ SEM and were analyzed using Student's paired t-test. Results. There was no difference in values for RR90 between 2 methods. In normal emptying group, no difference of T50 between 2 methods. 11 of the 23 patients had delayed gastric emptying. Quantitative estimates of T50 by extrapolation of a power exponential fit were, however, feasible in all 11 patients' calculation using total abdominal radioactivity compared to only 4 of these 11 patients by intragastric method. R2 also significantly improved by calculation using abdominal method compared to intragastric method. Normal emptying group (n = 12) Gastroparesis group (n = 11) intragastric abdominal intragastric abdominal method method method method 53 _+8 58 -+ 8 NS 88 _+23 80 _+6 NS RR90 (%) 113_+11 120_+11 NS 296_+256 194_+60 Tl/2 (4/11)* (11/11)* (min) R2 0.86_+0.1 0.97_+0.01 P<0.05 0.18_+0.28 0.83_+0.19 P<0.05 (8/I 1)* (11/11)* * number of quantitative estimate by power exponential fit NS: no statistical significance
Intestinal transit during fat-induced ileal brake was slower following by the CCK antagonist when compared to saline control (effect of i.v. agent: P < 0.01). Conclusion: Fat-induced ileal brake depends on CCK. Supported, in part, by NIH DK 46459. G3253
IMMUNONEUTRALIZATION OF CALCITONIN GENE-RELATED PEPTIDE (CGRP) DURING INHIBITION OF INTESTINAL TRANSIT BY FAT. HC Lin, JH Walsh, XT Zhao, LJ Wang, and H. Wong. Department of Medicine, Cedars-Sinai Medical Center, CURE: Digestive Diseases Research Center and UCLA, Los Angeles, CA. Calcitonin gene related peptide (CGRP) is associated with sensory neurons found throughout the gastrointestinal tract: CGRP is known to be a mediator for the control of acid secretion and blood flow. However, it is not known whether CGRP mediates the control of intestinal transit. Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the proximal 1/2 of gut depends on CGRP. Methods: Four dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the proximal (between fistulas) 1/2 of gut to induce the jejunal brake response (DDS 1996;41:326). 60mM oleate was perfused at 2 ml/min for 90 min as a pH 7.0 solution of mixed micelles. Thirty rain before perfusion, 0 (saline control) or 10 mg of CGRP antibody (Fab fragment) was delivered intravenously as:a bolus. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 min after the start of the 90-rain perfusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test. Results: (mean -+ SE) i.v. agent Saline control CGRP antibody
Intestinal transit % recovered 24.9 _+6.4 33.1 _+4.4
Sqrt AUC 21.6 + 3.2 24.5 _+2.6
Intestinal transit during fat-induced jejunal brake was not affected by the i.v. agent. Specifically, there was no difference in the rate of intestinal transit following CGRP antibody when compared with saline control. Conclusion: Inhibition of intestinal transit by fat in the proximal 1/2 of gut does not depend on CGRP. Supported, in part, by NIH DK 46459. G3254
Conclusions. Scintigraphic measurement of gastric emptying calculated using
the proportion of the abdominal radioactivity in the stomach offers substantial advantages over conventional methods, particularly in patients with gastroparesis. • G3252 FAT-INDUCED ILEAL BRAKE DEPENDS ON CHOLECYSTOKININ. HC Lin, XT Zhao, and LJ Wang,. Department of Medicine, Cedars-Sinai Medical Center, and UCLA, Los Angeles, CA. Slowing of intestinal transit by proximal gut fat (jejunal brake)(DDS 41:326, 1996) depends on CCK (DDS 41:1884, 1996). CCK is released similarly by fat in proximal or distal 1/2 of gut (Gastro 112:AI 167, 1997). Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the distal 1/2 of gut (ileal brake) depends on CCK. Methods: Four dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the distal 1/2 of gut (beyond midgut fistula) to induce the ileal brake response. 60raM oleate was perfused at 2 ml/min for 90 min as a pH 7.0 solution of mixed micelles. To test for the role of CCK, MK 329 (Merck), CCK-A receptor antagonist, at a dose of 0 (saline control) or 0.1 mg/kg was given intravenously as a bolus 10 min before the start of intestinal perfusion. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 rain after the start of the 90-rain peffusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test: Results: (mean + SE) i.v. agent Saline control MK329
Intestinal transit % recovered 43.9 -+ 14.0 28.1 _+8.9
Sqrt AUC 20.0 -+5.9 11.2_+2.7
INTESTINAL TRANSIT RESPONSE TO FAT IN THE PROXIMAL GUT DEPENDS ON 5-HYDROXYTRYPTAMINE. HC Lin, XT Zhao, and LJ Wang,. Department of Medicine, Cedars-Sinai Medical Center, and UCLA, Los Angeles, CA. Distension releases 5-hydroxytrytamine (5-HT) to stimulate intestinal motility via 5-HT3 receptors 0. However, it is not known whether slowing of intestinal transit by fat depended on 5-HT. Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the proximal 1/2 of gut (jejunal brake) (DDS 41:326, 1996) depended on 5-HT. Methods: Three dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the proximal 1/2 of gut (between fistulas) to induce the jejunal brake response. To keep the effect of distension constant but to vary the exposure to fat, buffer or 60mM oleate rain as a pH 7.0 solution of mixed micelles was perfused at 2 ml/min for 90 rain. To test for the role of 5-HT, Ondansetron, a 5-HT3 receptor antagonist, at a dose of 0 (equivolume saline as control) or 0.5 mg/kg was delivered into the intestinal test segment via the Foley catheter in the duodenal fistula. The antagonist was given as a bolus 5 min after the start of transit measurement. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 rain after the start of the 90-min perfusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test. Results: Intestinal transit (mean -+ SE) Perfusate Buffer
Luminal agent
% recovered
Sqrt AUC.
Saline control Ondansetron
96:0 - 4.0 57.9 -+ 15.9
42.3 -+4.5 32.4 -+ 6. I
Saline control Ondansetron
41.6 _+4.6 73.7 -+ 10.6
28.4 - 3.2 39.8 -+4.1
Olelate
A790 AGA ABSTRACTS
• G3251 EVALUATION OF GASTRIC EMPTYING BY MEASUREMENT OF PROPORTION OF INTRA-ABDOMINAL RADIOACTIVITY IN STOMACH. HC Lien. CS Chang, GH Chen, CH Kao, SC Tsai, SJ Wang. Taichung Veterans General Hospital, Taiwan, ROC. Background, Using scintigraphic techniques the rate of gastric emptying is usually calculated by quantifying the amount of radioactivity within a gastric region-of-interest and considering the time of meal completion as 100% retention. This technique has, however, significant limitations arising from subject movement and radionuclide gamma ray attenuation, which may render curvefitting difficult, particularly in patients with gastroparesis. In attempts to minimize these issues we have expressed the intragastric content as a percentage of the total abdominal radioactivity, and compare this method to the conventional one. Method. Twenty-three patients with non-ulcer dyspepsia (9 male, 14 female) consumed a mixed solid and liquid meal containing of 2 fried eggs labeled with 99mTc, 2 slices of toast and 500 ml of 5% glucose water (412kcal) in sitting position. Data were acquired at a rate of one frame every 5 minutes for 90 minutes from left anterior view. Time 0 was considered to represent the time of meal completion. The intragastric retention at 90 min (RR90), the 50% emptying time (TS0) calculated by a power exponential fit and R2 (1 - residual sum of squares/total sum of squares) represents the goodness of fit of power exponential fit were calculated using the two methods. Results were compared to an established normal range in which delayed gastric emptying was a RR90 > 68%. Data are expressed as mean -+ SEM and were analyzed using Student's paired t-test. Results. There was no difference in values for RR90 between 2 methods. In normal emptying group, no difference of T50 between 2 methods. 11 of the 23 patients had delayed gastric emptying. Quantitative estimates of T50 by extrapolation of a power exponential fit were, however, feasible in all 11 patients' calculation using total abdominal radioactivity compared to only 4 of these 11 patients by intragastric method. R2 also significantly improved by calculation using abdominal method compared to intragastric method. Normal emptying group (n = 12) Gastroparesis group (n = 11) intragastric abdominal intragastric abdominal method method method method 53 _+8 58 -+ 8 NS 88 _+23 80 _+6 NS RR90 (%) 113_+11 120_+11 NS 296_+256 194_+60 Tl/2 (4/11)* (11/11)* (min) R2 0.86_+0.1 0.97_+0.01 P<0.05 0.18_+0.28 0.83_+0.19 P<0.05 (8/I 1)* (11/11)* * number of quantitative estimate by power exponential fit NS: no statistical significance
Intestinal transit during fat-induced ileal brake was slower following by the CCK antagonist when compared to saline control (effect of i.v. agent: P < 0.01). Conclusion: Fat-induced ileal brake depends on CCK. Supported, in part, by NIH DK 46459. G3253
IMMUNONEUTRALIZATION OF CALCITONIN GENE-RELATED PEPTIDE (CGRP) DURING INHIBITION OF INTESTINAL TRANSIT BY FAT. HC Lin, JH Walsh, XT Zhao, LJ Wang, and H. Wong. Department of Medicine, Cedars-Sinai Medical Center, CURE: Digestive Diseases Research Center and UCLA, Los Angeles, CA. Calcitonin gene related peptide (CGRP) is associated with sensory neurons found throughout the gastrointestinal tract: CGRP is known to be a mediator for the control of acid secretion and blood flow. However, it is not known whether CGRP mediates the control of intestinal transit. Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the proximal 1/2 of gut depends on CGRP. Methods: Four dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the proximal (between fistulas) 1/2 of gut to induce the jejunal brake response (DDS 1996;41:326). 60mM oleate was perfused at 2 ml/min for 90 min as a pH 7.0 solution of mixed micelles. Thirty rain before perfusion, 0 (saline control) or 10 mg of CGRP antibody (Fab fragment) was delivered intravenously as:a bolus. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 min after the start of the 90-rain perfusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test. Results: (mean -+ SE) i.v. agent Saline control CGRP antibody
Intestinal transit % recovered 24.9 _+6.4 33.1 _+4.4
Sqrt AUC 21.6 + 3.2 24.5 _+2.6
Intestinal transit during fat-induced jejunal brake was not affected by the i.v. agent. Specifically, there was no difference in the rate of intestinal transit following CGRP antibody when compared with saline control. Conclusion: Inhibition of intestinal transit by fat in the proximal 1/2 of gut does not depend on CGRP. Supported, in part, by NIH DK 46459. G3254
Conclusions. Scintigraphic measurement of gastric emptying calculated using
the proportion of the abdominal radioactivity in the stomach offers substantial advantages over conventional methods, particularly in patients with gastroparesis. • G3252 FAT-INDUCED ILEAL BRAKE DEPENDS ON CHOLECYSTOKININ. HC Lin, XT Zhao, and LJ Wang,. Department of Medicine, Cedars-Sinai Medical Center, and UCLA, Los Angeles, CA. Slowing of intestinal transit by proximal gut fat (jejunal brake)(DDS 41:326, 1996) depends on CCK (DDS 41:1884, 1996). CCK is released similarly by fat in proximal or distal 1/2 of gut (Gastro 112:AI 167, 1997). Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the distal 1/2 of gut (ileal brake) depends on CCK. Methods: Four dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the distal 1/2 of gut (beyond midgut fistula) to induce the ileal brake response. 60raM oleate was perfused at 2 ml/min for 90 min as a pH 7.0 solution of mixed micelles. To test for the role of CCK, MK 329 (Merck), CCK-A receptor antagonist, at a dose of 0 (saline control) or 0.1 mg/kg was given intravenously as a bolus 10 min before the start of intestinal perfusion. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 rain after the start of the 90-rain peffusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test: Results: (mean + SE) i.v. agent Saline control MK329
Intestinal transit % recovered 43.9 -+ 14.0 28.1 _+8.9
Sqrt AUC 20.0 -+5.9 11.2_+2.7
INTESTINAL TRANSIT RESPONSE TO FAT IN THE PROXIMAL GUT DEPENDS ON 5-HYDROXYTRYPTAMINE. HC Lin, XT Zhao, and LJ Wang,. Department of Medicine, Cedars-Sinai Medical Center, and UCLA, Los Angeles, CA. Distension releases 5-hydroxytrytamine (5-HT) to stimulate intestinal motility via 5-HT3 receptors 0. However, it is not known whether slowing of intestinal transit by fat depended on 5-HT. Aim: The aim of this study was to test the hypothesis that inhibition of intestinal transit by fat in the proximal 1/2 of gut (jejunal brake) (DDS 41:326, 1996) depended on 5-HT. Methods: Three dogs were equipped with duodenal (10 cm from pylorus) and midgut (160 cm from pylorus) fistulas. The small intestine was compartmentalized with occluding Foley catheters placed into the distal limb of each fistula. Intestinal transit across a 150-cm test segment (between fistulas) was compared when fat was delivered into the proximal 1/2 of gut (between fistulas) to induce the jejunal brake response. To keep the effect of distension constant but to vary the exposure to fat, buffer or 60mM oleate rain as a pH 7.0 solution of mixed micelles was perfused at 2 ml/min for 90 rain. To test for the role of 5-HT, Ondansetron, a 5-HT3 receptor antagonist, at a dose of 0 (equivolume saline as control) or 0.5 mg/kg was delivered into the intestinal test segment via the Foley catheter in the duodenal fistula. The antagonist was given as a bolus 5 min after the start of transit measurement. Intestinal transit was measured by delivering 20 pCi 99m-Tc-DTPA as a bolus into the test segment 60 rain after the start of the 90-min perfusion, and counting the radioactivity in the output of the midgut fistula. Intestinal transit was represented by the cumulative % recovery of the radioactive marker and as the square root of the area under the transit curve (sqrt AUC) where 47.5 = fastest transit. The sqrt AUC results were compared using paired t-test. Results: Intestinal transit (mean -+ SE) Perfusate Buffer
Luminal agent
% recovered
Sqrt AUC.
Saline control Ondansetron
96:0 - 4.0 57.9 -+ 15.9
42.3 -+4.5 32.4 -+ 6. I
Saline control Ondansetron
41.6 _+4.6 73.7 -+ 10.6
28.4 - 3.2 39.8 -+4.1
Olelate