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Mechanisms of liquid and gas gastroesophageal reflux in healthy preterm infants. A combined manometric and impedance study
was previously shown to be involved in the secretory effects of bile acids on the colonocytes, the potential involvement of histamine receptors was also examined in current studies. Both cimetidine (1 raM) and diphenhydramine (0.1raM), H2 and H1 histamine receptor antagonists respectively, had no effect on inhibition of 36C1 uptake by TDC. In conclusion, our studies, provide direct evidence for inhibition of human intestinal luminal CI'/OH (HCO~) exchange activity by bile acids. The results of our studies demonstrate that bile acid effects on the apical CI/OH exchange in Caco2 cells are not mediated via histamine receptors and involve a cAMP-independent but Ca + +, PKC and PI3 kinase-dependent pathways.
MeCP2 genotype and GI phenotype correlative clinical study in children with Rett syndrome. Methods: Thirty-six consecutive females with a mean (SD) age of 7.4 (3.4) years were ascertained and examined at The Rett Syndrome clinic at The Kennedy Krieger Institute. Genomic DNA was isolated from peripheral lymphocytes and mutation analysis was performed by using a combination of DHPLC (detection of heteroduplexes by ion-pair reverse phase HPLC) and direct sequencing (Genomics 1998;52:44-49). Mutation analysis of the MeCP2 gene was correlated with failure to thrive (z-score<-2SD), pathological GERD, constipation and oropharyngeal dysphagia. Results: Twenty-six patients with Rett syndrome showed a wide distribution of mutations throughout the exon 3 and 4 of the MeCP2 gene (Table 1). Among these patients, all but one manifested clinical symptoms associated with gastrointestinal dysfunction requiring medical intervention. Oropharyngeal dysphagia (4) associated well (p<0.05) with mutations localized to the proximal portion of the MeCP2 gene suggesting that more proximal mutations may predispose to neuroenteric dysfunction. A similar association has also been noted in the presence of more proximal MeCP2 mutations and the severity of central and autonomic neuronal function, including frequency and manageability of seizures, respiratory difficulties and the ability to walk. Conclusions: MeCP2 gene mutations commonly associate with the gastrointestinal manifestation of Rett syndrome. Proximal mutations within the MeCP2 gene may also correlate with more severe forms of swallowing dysfunction. Future challenges include the application of video fluoroscopy and esophageal manometry in the diagnosis and management of patients with Rett syndrome with symptoms of oropharyngeal dysphagia.
301 Mechanisms of Liquid and Gas Gastroesophageal Reflux in Healthy Preterm lafants. A Combined Manometric and Impedance Study Taher Omari, Nathalie Rommel, Esther Staunton, Louise Goodchild, Ross Lontis, Ross I-hslam, John Dent, Geoffrey Davidson Background: In preterm infants, transient lower esophageal sphincter relaxation (TLESR) is the predominant mechanism of gastroesophageal reflux (GER) detected manometrically, by the presence of esophageal common cavity episodes (CC), and/or by pH probe. TLESRs triggering CC, but not acid GER, are common during the early post-prandial period, however, the precise nature (liquid/gas) of these reflux episodes has not been previously determined. The aim of this study was to use a novel combined manometry and impedance assembly to charactense the mechanisms of liquid and gas GER in preterm infants. Methods: 5 preterm infants (4M: IF) ranging in weight from 2480-3180g were studied at a post menstrual age of 34 to 37 weeks. Combined manometry and multi-channel intralumina[ impedance (MII) was performed using a novel lower esophageal sphincter (LES) sleeve assembly (OD 2.5mm) incorporating a 9cm array of 6 impedance rings spaced at 1.5cm intervals for MII measurement. After placement of the assembly infants were fed with 45-80ml of expressed breast milk via an assembly infusion port and then esophageal manometry and MII were recorded for 4 hours post prandially. Episodes of liquid and gas GER were identified using standard MII cnteria and the esophageal motor mechanism(s) of GER triggering characterised. Results: 71 GER episodes were recorded consisting of 57(80%) liquid, 8(11%) gas and 6(8%) combined liqind/gas. The mean(SE) bolus clearance time of liquid GER was 13.8(1.1) sec. The proximal extent of GER was >9cm for 43(65%) of liquid or mixed GER episodes. TLESRwas the predominant mechanism of reflux, triggering 70% of all GER episodes. Other GERmechanisms identified included swallow related LES relaxation (10%), vomiting (6%) and straining in association with low LES pressure (3%). Of 70 TLESRs recorded, 20(29%) wereuneventful, 44(63%) triggered liquid GER, 3(4%) triggered gas GER and 3(4%) triggered combined liquid/gas GER. TLESR triggered exclusively liquid GER in the first postrandial hour. Conclusions: In preterm infants, the majority of GER is liquid in nature and usually extends into the proximal oesophagus. TLESR is the predominant mechanism of all GER in these infants.
MeCP2
N
Age Range G E R D
Constipation
(~) R I ~ (Q/W) T158M RtflSX R255X R270X P,294X R306C 79Md(1)/1161d~(6) 801dd(C) No mutation=
2 3 5 4 5 2 2 2 1 10
4-8 4-7 2-16 3,5-11 3,5-10 4-13 4-5 4 3.5 3-15
Failure to
Dysphagla
~,~,e 0 0 2 1 3 0 0 1 0 I
1 2 3 2 3 2 1 1 1 4
1 3 4 3 3 2 1 1 0 5
2 0 2 0 0 0 0 0 0 0
304 Regional Variations in SP, VIP and NOS in Colon Circular muscle from Children With Slow Transit Constipation Bridget R. Southwell, Pare Farmer, John H. Hutson Coordinated firing of inhibitory and excitatory motor nerves controls contraction and relaxation of muscle producing movement of stools through the colon. Reductions in substance P (SP) and increases in vasoactive intestinal peptide (VIP) and have been observed in nerve fibres in colonic circular muscle (CCM) in children and adults with slow transit constipation (STC), suggesting a relationship between neurotransmitter levels and slowed colonic motility t. Aim: To determine regional variations in excitatory and inhibitory transmitters in nerve fibres in colon circular muscle CCM) from children with STC The density of nerve fibres containing SP, VIP and nitric oxide synthase (NOS) was quantified. Methods: STC was diagnosed using scintigraphy (radionncleide marker and multiple images) as radioactivity retained in the right and transverse colon at 48 hr. Seromuscular biopsies of CCM were collected laparascopically from right transverse (RT), left transverse (LT) and sigmoid colon and the location and density of neurotransmitters was determined by fluorescence immunohtstochemistry and confocal microscopy, n = 19. Results: There was regional variation in the density of transmitters in CCM. Density (/0.025 mm 2) of SP-1R fibres was 9 -+ 1 (mean _+SEM) in RT, < 12 _+2 in LT, < sigmoid colon (17 +- 2). There was bimodal distribution of density, with 84, 42 & 36% of patients with low SP in RT, LT and sigmoid colon resp. 21% had low SP in all 3 regions. VIP density was > in LT (33+3) than sigmoid (27+_3) or RT (21+_3) colon. NOS density was > in LT (37+_6) than sigmoid (32+_4) or RT (26+_3) colon. Ratios of NOS:SP and VIP:SP were highest in LT and lowest in sigmoid colon. Conc[: There is regional variation in the density of SP, VIP and NOS in CCM from children with STC. SP (excitatory transmitter) was lowest in RT, while inhibitory transmitters VIP and NOS were highest in LT colon. The ratio of inhibitory:excitatory transmitter density was highest in the LT colon. This could result in greater relaxation, reduced contraction and reduced motility in the transverse colon. 1. Hutson, J.M., McNamara, J., Gibb, S. & Shin, YM. Slow transit constipation in children. J Paediatr Child Health 37, 426-30 (2001).
302 Baclofen Reduces Emesis and Gastroesophageal Reflux in Neurologically Impaired Children with Gastroesophageal Reflux Disaese Masanobu Kawai, Shinobu Ida, Norikazu Yoshimura, Hisayoshi Kawahara Neurologically impaired (NI) children frequently have various symptoms caused by gastroesophageal reflux disease (GERD). Therapeutic options for GERD have been limited in these patients. The GABAB agonist baclofen has recently been shown to reduce postprandial acid reflux in adult patients with GERD by reducing the incidence of transient lower esophageal sphincter relaxations. The present study was undertaken to investigate the effects of badofen on clinical symptoms and acid refiuxes in pediatric N[ patients. Eight NI children with cerebral palsy, aged from 2 months to 16 year of age(median age: 5 years), were studied. All patients showed frequent emesis and were diagnosed with GERD by 24-hr esophageal pH data (the percentage time of esophageal pH<4.0 over 5.0). Baclofen (0.7mg/kg/day) was administered orally or via naso-gasmc tube in three divided doses 30 minutes before meals for 7 days. The frequency of emesis was graded as follows: grade I > twice a week; grade I1 > once a day; grade III> twice a day; grade IV every time after meal. The clinical symptom was scored on a scale of 1 to 4 according to the grading of emesis (grade I was score 1). The esophageal pH data were analyzed for the number of acid refluxes and the percentage time of esophageal pH < 4 0 . The symptom scores and the esophageal pH data were compared between the values before the administration of baclofen and those on the last day of this trial. Data are expressed as medians and interquartile ranges. Statistical analystswas performed with Wilcoxon's signed rank test. The symptom scores decreased significantly from 4 (3-4) to 1 (1-3) (p=0.02). The number of acid refluxes decreased signihcantly from 193 (149-295) to 124 (67-211) in 24 hours (p=0.01) and from 94(66182) to 62(42-109) in the postprandial 2 hours (p<0.05). The percentage time of esophageal pH<4.0 did not show any sigmficant difference in 24 hours (17(13-24) vs 11(4-24),p = 0.21) and in the postprandial 2 hours (26(16-35) vs 14(8-31),p =0.40). No adverse effects were noted except mild hypotonia in one subject during this trial. In conclusion, a short-term baclofen administration is effective to reduce the frequency of emesis without significant adverse effects and the number of acid refluxes in NI children with GERD.
3O5 Methotrexate as Rescue Therapy in Pediatric Crohn's Disease Joel R. Rosh, Nader N. Yonssef, Stephanie Schuckalo, Jaya Punati, Barbara Fehling, Richard L. Mones AIMS: There is no clearly preferred therapy for children with Crohn's disease who develop intolerance or lack of clinical response to 6-mercaptopurine (6MP). This study looks at the efficacy of immune-modulation with methotrexate (MTX) as maintenance therapy in a cohort of such patients. Primary outcome measure was a significant reduction in the Pediatric Crohn's Disease Activity Index (PCDAI) score. Secondary measures were need for surgical resection and continued need for infliximab administration. SUBJECTS & METHODS: Of the 240 children with inflammatory bowel disease actively followed at our center, 12 with biopsy-proven Crohn's disease (6 male, aged 13.7 +/- 5.7 years) were withdrawn from 6MP therapy and started on weekly subcutaneous MTX. 6MP was withdrawn due to lack of clinical response or drug intolerance (6 patients). Intolerance was defined as nausea, vomiting and increased abdominal pain (5) and fever with severe arthralgia (1) with drug challenge and withdrawal. Lack of clinical response was defined by elevated PCDA1 scores and/or need for surgical intervention. At the time of MTX introduction, all patients were requiring multiple infusions of infliximab (5.6 +/- ].7 infusions / patient). Time from diagnosis of Crohn's disease until introduction of MTX was 4.3 +/- 2.4 years. Prior to MTX,
303 X-linked Methyl CpG Binding Protein (MeCP2) Gene Mutations in Children with Rett Syndrome: Correlation with Clinical Severity of Gastrointestinal Symptoms Carmen Cuffari, Anil Darbari, Genila Bibat, Sakkubai Naidu Background: Rett syndrome is a neurodevelopmental disorder that is caused by a number of mutations in the MeCP2 gene located on chromosome Xq28. Mutations in the MeCP2 proteinresults in a loss of function leading to developmental regression. The GI manifestations in these children vary in clinical severity and may be genotype dependent. Aim: To report a
A-41
AGA Abstracts
MeCP2 genotype and GI phenotype correlative clinical study in children with Rett syndrome. Methods: Thirty-six consecutive females with a mean (SD) age of 7.4 (3.4) years were ascertained and examined at The Rett Syndrome clinic at The Kennedy Krieger Institute. Genomic DNA was isolated from peripheral lymphocytes and mutation analysis was performed by using a combination of DHPLC (detection of heteroduplexes by ion-pair reverse phase HPLC) and direct sequencing (Genomics 1998;52:44-49). Mutation analysis of the MeCP2 gene was correlated with failure to thrive (z-score<-2SD), pathological GERD, constipation and oropharyngeal dysphagia. Results: Twenty-six patients with Rett syndrome showed a wide distribution of mutations throughout the exon 3 and 4 of the MeCP2 gene (Table 1). Among these patients, all but one manifested clinical symptoms associated with gastrointestinal dysfunction requiring medical intervention. Oropharyngeal dysphagia (4) associated well (p<0.05) with mutations localized to the proximal portion of the MeCP2 gene suggesting that more proximal mutations may predispose to neuroenteric dysfunction. A similar association has also been noted in the presence of more proximal MeCP2 mutations and the severity of central and autonomic neuronal function, including frequency and manageability of seizures, respiratory difficulties and the ability to walk. Conclusions: MeCP2 gene mutations commonly associate with the gastrointestinal manifestation of Rett syndrome. Proximal mutations within the MeCP2 gene may also correlate with more severe forms of swallowing dysfunction. Future challenges include the application of video fluoroscopy and esophageal manometry in the diagnosis and management of patients with Rett syndrome with symptoms of oropharyngeal dysphagia.
301 Mechanisms of Liquid and Gas Gastroesophageal Reflux in Healthy Preterm lafants. A Combined Manometric and Impedance Study Taher Omari, Nathalie Rommel, Esther Staunton, Louise Goodchild, Ross Lontis, Ross I-hslam, John Dent, Geoffrey Davidson Background: In preterm infants, transient lower esophageal sphincter relaxation (TLESR) is the predominant mechanism of gastroesophageal reflux (GER) detected manometrically, by the presence of esophageal common cavity episodes (CC), and/or by pH probe. TLESRs triggering CC, but not acid GER, are common during the early post-prandial period, however, the precise nature (liquid/gas) of these reflux episodes has not been previously determined. The aim of this study was to use a novel combined manometry and impedance assembly to charactense the mechanisms of liquid and gas GER in preterm infants. Methods: 5 preterm infants (4M: IF) ranging in weight from 2480-3180g were studied at a post menstrual age of 34 to 37 weeks. Combined manometry and multi-channel intralumina[ impedance (MII) was performed using a novel lower esophageal sphincter (LES) sleeve assembly (OD 2.5mm) incorporating a 9cm array of 6 impedance rings spaced at 1.5cm intervals for MII measurement. After placement of the assembly infants were fed with 45-80ml of expressed breast milk via an assembly infusion port and then esophageal manometry and MII were recorded for 4 hours post prandially. Episodes of liquid and gas GER were identified using standard MII cnteria and the esophageal motor mechanism(s) of GER triggering characterised. Results: 71 GER episodes were recorded consisting of 57(80%) liquid, 8(11%) gas and 6(8%) combined liqind/gas. The mean(SE) bolus clearance time of liquid GER was 13.8(1.1) sec. The proximal extent of GER was >9cm for 43(65%) of liquid or mixed GER episodes. TLESRwas the predominant mechanism of reflux, triggering 70% of all GER episodes. Other GERmechanisms identified included swallow related LES relaxation (10%), vomiting (6%) and straining in association with low LES pressure (3%). Of 70 TLESRs recorded, 20(29%) wereuneventful, 44(63%) triggered liquid GER, 3(4%) triggered gas GER and 3(4%) triggered combined liquid/gas GER. TLESR triggered exclusively liquid GER in the first postrandial hour. Conclusions: In preterm infants, the majority of GER is liquid in nature and usually extends into the proximal oesophagus. TLESR is the predominant mechanism of all GER in these infants.
MeCP2
N
Age Range G E R D
Constipation
(~) R I ~ (Q/W) T158M RtflSX R255X R270X P,294X R306C 79Md(1)/1161d~(6) 801dd(C) No mutation=
2 3 5 4 5 2 2 2 1 10
4-8 4-7 2-16 3,5-11 3,5-10 4-13 4-5 4 3.5 3-15
Failure to
Dysphagla
~,~,e 0 0 2 1 3 0 0 1 0 I
1 2 3 2 3 2 1 1 1 4
1 3 4 3 3 2 1 1 0 5
2 0 2 0 0 0 0 0 0 0
304 Regional Variations in SP, VIP and NOS in Colon Circular muscle from Children With Slow Transit Constipation Bridget R. Southwell, Pare Farmer, John H. Hutson Coordinated firing of inhibitory and excitatory motor nerves controls contraction and relaxation of muscle producing movement of stools through the colon. Reductions in substance P (SP) and increases in vasoactive intestinal peptide (VIP) and have been observed in nerve fibres in colonic circular muscle (CCM) in children and adults with slow transit constipation (STC), suggesting a relationship between neurotransmitter levels and slowed colonic motility t. Aim: To determine regional variations in excitatory and inhibitory transmitters in nerve fibres in colon circular muscle CCM) from children with STC The density of nerve fibres containing SP, VIP and nitric oxide synthase (NOS) was quantified. Methods: STC was diagnosed using scintigraphy (radionncleide marker and multiple images) as radioactivity retained in the right and transverse colon at 48 hr. Seromuscular biopsies of CCM were collected laparascopically from right transverse (RT), left transverse (LT) and sigmoid colon and the location and density of neurotransmitters was determined by fluorescence immunohtstochemistry and confocal microscopy, n = 19. Results: There was regional variation in the density of transmitters in CCM. Density (/0.025 mm 2) of SP-1R fibres was 9 -+ 1 (mean _+SEM) in RT, < 12 _+2 in LT, < sigmoid colon (17 +- 2). There was bimodal distribution of density, with 84, 42 & 36% of patients with low SP in RT, LT and sigmoid colon resp. 21% had low SP in all 3 regions. VIP density was > in LT (33+3) than sigmoid (27+_3) or RT (21+_3) colon. NOS density was > in LT (37+_6) than sigmoid (32+_4) or RT (26+_3) colon. Ratios of NOS:SP and VIP:SP were highest in LT and lowest in sigmoid colon. Conc[: There is regional variation in the density of SP, VIP and NOS in CCM from children with STC. SP (excitatory transmitter) was lowest in RT, while inhibitory transmitters VIP and NOS were highest in LT colon. The ratio of inhibitory:excitatory transmitter density was highest in the LT colon. This could result in greater relaxation, reduced contraction and reduced motility in the transverse colon. 1. Hutson, J.M., McNamara, J., Gibb, S. & Shin, YM. Slow transit constipation in children. J Paediatr Child Health 37, 426-30 (2001).
302 Baclofen Reduces Emesis and Gastroesophageal Reflux in Neurologically Impaired Children with Gastroesophageal Reflux Disaese Masanobu Kawai, Shinobu Ida, Norikazu Yoshimura, Hisayoshi Kawahara Neurologically impaired (NI) children frequently have various symptoms caused by gastroesophageal reflux disease (GERD). Therapeutic options for GERD have been limited in these patients. The GABAB agonist baclofen has recently been shown to reduce postprandial acid reflux in adult patients with GERD by reducing the incidence of transient lower esophageal sphincter relaxations. The present study was undertaken to investigate the effects of badofen on clinical symptoms and acid refiuxes in pediatric N[ patients. Eight NI children with cerebral palsy, aged from 2 months to 16 year of age(median age: 5 years), were studied. All patients showed frequent emesis and were diagnosed with GERD by 24-hr esophageal pH data (the percentage time of esophageal pH<4.0 over 5.0). Baclofen (0.7mg/kg/day) was administered orally or via naso-gasmc tube in three divided doses 30 minutes before meals for 7 days. The frequency of emesis was graded as follows: grade I > twice a week; grade I1 > once a day; grade III> twice a day; grade IV every time after meal. The clinical symptom was scored on a scale of 1 to 4 according to the grading of emesis (grade I was score 1). The esophageal pH data were analyzed for the number of acid refluxes and the percentage time of esophageal pH < 4 0 . The symptom scores and the esophageal pH data were compared between the values before the administration of baclofen and those on the last day of this trial. Data are expressed as medians and interquartile ranges. Statistical analystswas performed with Wilcoxon's signed rank test. The symptom scores decreased significantly from 4 (3-4) to 1 (1-3) (p=0.02). The number of acid refluxes decreased signihcantly from 193 (149-295) to 124 (67-211) in 24 hours (p=0.01) and from 94(66182) to 62(42-109) in the postprandial 2 hours (p<0.05). The percentage time of esophageal pH<4.0 did not show any sigmficant difference in 24 hours (17(13-24) vs 11(4-24),p = 0.21) and in the postprandial 2 hours (26(16-35) vs 14(8-31),p =0.40). No adverse effects were noted except mild hypotonia in one subject during this trial. In conclusion, a short-term baclofen administration is effective to reduce the frequency of emesis without significant adverse effects and the number of acid refluxes in NI children with GERD.
3O5 Methotrexate as Rescue Therapy in Pediatric Crohn's Disease Joel R. Rosh, Nader N. Yonssef, Stephanie Schuckalo, Jaya Punati, Barbara Fehling, Richard L. Mones AIMS: There is no clearly preferred therapy for children with Crohn's disease who develop intolerance or lack of clinical response to 6-mercaptopurine (6MP). This study looks at the efficacy of immune-modulation with methotrexate (MTX) as maintenance therapy in a cohort of such patients. Primary outcome measure was a significant reduction in the Pediatric Crohn's Disease Activity Index (PCDAI) score. Secondary measures were need for surgical resection and continued need for infliximab administration. SUBJECTS & METHODS: Of the 240 children with inflammatory bowel disease actively followed at our center, 12 with biopsy-proven Crohn's disease (6 male, aged 13.7 +/- 5.7 years) were withdrawn from 6MP therapy and started on weekly subcutaneous MTX. 6MP was withdrawn due to lack of clinical response or drug intolerance (6 patients). Intolerance was defined as nausea, vomiting and increased abdominal pain (5) and fever with severe arthralgia (1) with drug challenge and withdrawal. Lack of clinical response was defined by elevated PCDA1 scores and/or need for surgical intervention. At the time of MTX introduction, all patients were requiring multiple infusions of infliximab (5.6 +/- ].7 infusions / patient). Time from diagnosis of Crohn's disease until introduction of MTX was 4.3 +/- 2.4 years. Prior to MTX,
303 X-linked Methyl CpG Binding Protein (MeCP2) Gene Mutations in Children with Rett Syndrome: Correlation with Clinical Severity of Gastrointestinal Symptoms Carmen Cuffari, Anil Darbari, Genila Bibat, Sakkubai Naidu Background: Rett syndrome is a neurodevelopmental disorder that is caused by a number of mutations in the MeCP2 gene located on chromosome Xq28. Mutations in the MeCP2 proteinresults in a loss of function leading to developmental regression. The GI manifestations in these children vary in clinical severity and may be genotype dependent. Aim: To report a
A-41
AGA Abstracts