Lack of association of Helicobacter pylori infection with gastric hypersensitivity or delayed gastric emptying in functional dyspepsia

OBJECTIVE: We evaluated the relationship between Helicobacter pylori (H. pylori) infection and gastric sensitivity to distention or gastric emptying rate to define the role of H. pylori in the pathogenesis of functional dyspepsia. METHODS: Gastric barostat, gastric emptying scintigraphy, and 13C urea breath test were performed in 34 consecutive patients with functional dyspepsia. RESULTS: Between H. pylori-positive and -negative patients with functional dyspepsia, there were no significant differences in basal tone (57.2 +/- 15.0 ml vs 66.8 +/- 18.3 ml), compliance (41.0 +/- 11.2 ml/mm Hg vs 38.2 +/- 11.8 ml/mm Hg), threshold of first sense (3.6 +/- 2.7 mm Hg vs 2.3 +/- 1.5 mm Hg), threshold of abdominal discomfort (9.4 +/- 4.0 mm Hg vs 7.3 +/- 1.9 mm Hg), and postprandial receptive relaxation (115.4 +/- 89.7 ml vs 99.0 +/- 88.7 ml), measured by gastric barostat. Half gastric emptying time (88.6 +/- 24.5 min vs 91.4 +/- 21.6 min) and retention rate at 120 min (32.8 +/- 17.8% vs 41.9 +/- 20.1%) were also similar between the two groups. CONCLUSION: H. pylori infection was not associated with gastric hypersensitivity to distention or delayed gastric emptying.     

功能性消化不良患者胃机械感觉过敏

背景：功能性消化不良（FD）是临床上常见的症候群，其发病机制目前尚未完全阐明，现逐步认识到胃感觉过敏可能在FD的发病中起着重要作用。目的：探讨FD患者是否存在胃机械感觉过敏，同时了解胃顺应性变化。方法：应用电子恒压器对52例FD患者和15名健康对照者进行检查，采用恒压梯度扩张法扩张近端胃，获得胃机械扩张感知、不适、疼痛的压力和容积闽值，计算近端胃顺应性。结果：FD患者与健康对照者相比最小扩张压（MDP）无显著性差异：FD患者对胃机械扩张刺激的感知阈值、不适闽值、疼痛压力阈值均较健康对照者显著下降，40．4％的患者胃感知感觉过敏，46．2％的患者胃不适感觉过敏，51．9％的患者胃疼痛感觉过敏；FD患者胃感知和疼痛容积闽值较健康对照者显著降低。FD患者近端胃顺应性与健康对照组相比无显著性差异（P〉0．05）。胄机械感觉压力闽值与近端胃顺应性无关。结论：部分FD患者中存在着胃机械感觉过敏，近端胃顺应性正常。     

The etiologic role of gastric hypersensitivity in functional dyspepsia in Korea

To evaluate the role of gastric hypersensitivity and the relationship between gastric hypersensitivity and delayed gastric emptying in Korean functional dyspepsia (FD) patients, the authors performed gastric barostat and gastric emptying scintigraphy in 64 FD patients and compared these results with those of control subjects. Basal tones and gastric compliance were similar in control subjects and patients. However, threshold of abdominal discomfort was lower in FD patients than in control subjects (8.9 +/- 3.6 mmHg and 14.5 +/- 3.7 mmHg respectively; p < 0.05). Twenty-four of 64 patients (37.5%) experienced abdominal discomfort at a pressure less than 7 mmHg above minimal distending pressure (corresponding to the 95th percentile of normal values). Half time of solid-phase gastric emptying in patients and control subjects was not significantly different. Twenty-three of 64 patients (35.9%) had delayed gastric emptying compared with control subjects (normal ranges were mean +/- two standard deviations in control subjects). Thresholds of abdominal discomfort were not significantly different in patients with and without delayed gastric emptying (9.3 +/- 4.0 mL/mmHg vs. 8.6 +/- 3.3 mL/mmHg). There were also no significant differences in the proportion of patients with delayed gastric emptying between patients with and without gastric hypersensitivity. In conclusion, gastric hypersensitivity plays an important role in FD, and the presence of gastric hypersensitivity was not related to the presence of delayed gastric emptying.     

肥大细胞在胃感觉过敏患者胃黏膜中的改变

目的：了解国人功能性消化不良（FD）患者是否存在胃机械感觉过敏，对胃感觉过敏患者胃黏膜肥大细胞数量及脱颗粒情况进行研究，探讨肥大细胞在胃感觉过敏中的作用。方法：运用电子恒压器测定40例FD患者和15例正常人的胃感觉阈值。根据感知阈值将23例FD患者分为两组：感觉正常组（FD－N）和感觉过敏组（FD－H）。免疫组化方法染色肥大细胞，计数肥大细胞数；图像分析了解肥大细胞在扩张刺激前后平均吸光度值（A）的变化；电镜观察大细胞超微结构改变。结果：FD患者对胃机械扩张刺激的感知阈值，不适阀值，疼痛阈值均较正常人显著下降（P＜0．01，P＜0．01，P＜0．05），感觉过敏感患者近端胃黏膜肥大细胞数量明显多于FD－N组和对照组（P＜0．05）。刺激前后感觉过敏患者肥大细胞平均A值减少百分数较FD－N组和对照组明显增多（P＜0．05），电镜观察到肥大细胞与神经末梢关系密切，肥大细胞释放的颗粒有向神经末梢靠扰趋势。结论：部分FD患者存在胃机械感觉过敏；胃感觉过敏与胃黏膜肥大细胞数量增多，脱颗粒增加有关。     

The proximal stomach and postprandial symptoms in functional dyspeptics

OBJECTIVES: It remains unclear whether postprandial symptom profiles in patients with visceral hypersensitivity and in those with impaired fundic accommodation differ. Therefore, we evaluated the postprandial symptoms in functional dyspepsia (FD) patients classified according to proximal stomach function. In addition, the effect of gastric relaxation induced by sumatriptan on postprandial symptoms was studied in FD patients with impaired fundic accommodation. METHODS: Twenty-five healthy volunteers (HVs) and 44 FD patients filled out a disease-specific questionnaire (Nepean Dyspepsia Index) and underwent a gastric barostat study to evaluate visceral sensitivity, meal-induced fundic relaxation, and postprandial symptoms. Postprandial symptoms evoked by a drink test or reported during the barostat study were compared between FD patients subdivided according to the underlying pathophysiological mechanism. Finally, the effect of sumatriptan on postprandial symptoms evoked by a drink test was investigated in HVs and in FD patients with impaired fundic accommodation. RESULTS: There was no clear relationship between any of the 15 Nepean Dyspepsia Index symptoms and proximal stomach function. Postprandial symptoms evoked during the barostat study or after the drink tests were significantly higher in FD patients than in HVs; however, no clear differences in symptom profile could be demonstrated between the different subclasses of FD. Sumatriptan did not affect the maximal ingested volume or the postprandial symptoms in HVs or FD patients after a drink test. CONCLUSIONS: No clear relationship could be demonstrated between postprandial symptoms and proximal stomach function.     

Gastric Hypersensitivity in Nonulcer Dyspepsia An Inconsistent Finding

Visceral hypersensitivity is claimed to beinvolved in the pathogenesis of nonulcer dyspepsia(NUD). We evaluated whether gastric hypersensitivity isa consistent finding in an unselected group of NUDpatients. In 11 patients and 20 healthy controls, astandardized gastric distension was performed using agastric barostat. Perception was scored by aquestionnaire and compared between the two groups. Therewas a linear pressure/volume relationship duringgastric distension in both groups. The pain threshold inNUD patients was significantly lower compared tocontrols [5.5 ± 4.0 mm Hg above minimaldistending pressure (mdp) and 10.2 ± 2.2 mm Hg above mdp,respectively, P < 0.004], irrespective of the H.pylori status. However, more than 50% of the NUDperception scores were in the control range at mostdistension levels. Gastric hypersensitivity could be confirmed inNUD patients as a group. However, there is aconsiderable overlap concerning perception in responseto distension between unselected NUD patients andcontrols.     

Rectal distention testing in patients with irritable bowel syndrome: sensitivity,specificity, and predictive values of pain sensory thresholds

BACKGROUND & AIMS: Visceral hypersensitivity was detected in patients with functional gastrointestinal disorders and has been proposed as a biological marker of irritable bowel syndrome (IBS). The purpose of this study was to assess the sensitivity, specificity, and the predictive values of pain thresholds evaluated by rectal distention using an electronic barostat in patients with or without IBS and in control subjects. METHODS: Patients were diagnosed according to Rome II criteria. Rectal sensory thresholds were determined in 164 patients (86 IBS patients, 26 painless constipation, 21 functional dyspepsia, and 31 miscellaneous conditions) and in 25 normal controls. All subjects underwent a series of rectal isobaric distentions using an electronic barostat. The bag was progressively distended from 0 to 48 mm Hg and, in response to distention, subjects reported on discomfort or pain. RESULTS: Pain thresholds were lower in IBS patients (30.4 +/- 6.7 mm Hg) compared with controls (44.5 +/- 5), painless constipated (45.4 +/- 5.3), functional dyspepsia (39.4 +/- 7.8), and miscellaneous patients (43.2 +/- 5.5). At the level of 40 mm Hg, the sensitivity of the rectal barostat to identify IBS patients from normal subjects and non-IBS patients was 95.5% and its specificity was 71.8%. The positive predictive value was 85.4%. The negative predictive value was 90.2%. CONCLUSIONS: Lowered rectal pain threshold is a hallmark of IBS patients. Rectal barostat testing is useful to confirm the diagnosis of IBS and to discriminate IBS from other causes of abdominal pain.     

The selective serotonin reuptake inhibitor fluoxetine does not change rectal sensitivity and symptoms in patients with irritable bowel syndrome: a double blind, randomized, placebo-controlled study.

BACKGROUND & AIMS: Although widely prescribed, the evidence for the use of antidepressants for the treatment of irritable bowel syndrome (IBS) is limited. In this study, we hypothesized that fluoxetine (Prozac), a selective serotonin reuptake inhibitor, has visceral analgesic properties, leading to increased sensory thresholds during rectal distention and improvement of symptoms, in particular in IBS patients with visceral hypersensitivity. METHODS: Forty non-depressed IBS patients underwent a rectal barostat study to assess the sensitivity to rectal distention before and after 6 weeks of treatment with fluoxetine 20 mg or placebo. Abdominal pain scores, individual gastrointestinal symptoms, global symptom relief, and psychologic symptoms were assessed before and after the intervention. RESULTS: At baseline, 21 of 40 patients showed hypersensitivity to rectal distention. Fluoxetine did not significantly alter the threshold for discomfort/pain relative to placebo, either in hypersensitive (19 +/- 3 vs. 22 +/- 2 mm Hg above MDP) or in normosensitive (34 +/- 2 vs. 39 +/- 4 mm Hg above MDP) IBS patients. Overall, 53% of fluoxetine-treated patients and 76% of placebo-treated patients reported significant abdominal pain scores after 6 weeks (not significant). In contrast, in hypersensitive patients only, fluoxetine significantly reduced the number of patients reporting significant abdominal pain. Gastrointestinal symptoms, global symptom relief, and psychologic symptoms were not altered. CONCLUSIONS: Fluoxetine does not change rectal sensitivity in IBS patients. Possible beneficial effects on pain perception need to be confirmed in larger trials.     

饮水负荷试验与电子恒压器法测定胃感觉功能的比较

目的建立简单易行、非侵入性、符合胃肠生理的检测胃感觉阈值的方法。方法用饮水负荷试验和电子恒压器法分别对15例健康自愿者和30例功能性消化不良患者的胃感知和不适阈值进行测定。了解饮水负荷试验测定胃感觉阈值的敏感性、特异性、符合率,以及二者之间有无相关性。结果与电子恒压器法(用容积表示感觉阈值)相比较,饮水负荷试验测定胃感知阈值和不适阈值的敏感性为76.9%和75%,特异性为100%和90.9%,符合率为93.3%和86.7%,两种方法所测定的结果具有良好的相关性(P值均<0.01)。与用电子恒压器测得的压力值表示的感觉阈值进行比较,饮水负荷试验测定胃感知和不适阈值的敏感性为85.7%和81.8%,特异性为93.5%和91.2%,二者的符合率为91.1%和88.9%,两种方法所测得的结果也具有良好的相关性(P值均<0.01)。结论与电子恒压器相比,饮水负荷试验测定胃感觉阈值具有较高的特异性和符合率,以及良好的相关性,可作为消化不良患者胃感觉功能临床辅助诊断和初筛检查,在基层医院有广泛的应用前景。     

Correlation of Gastric Liquid Emptying with Various Thresholds of Sensation in Healthy Controls and Patients with Functional Dyspepsia

Our objective was to investigate the correlation between gastric emptying and sensation in patients with functional dyspepsia (FD). Thirty patients with FD and 15 controls were studied. Proximal gastric compliance and sensation thresholds were measured with a barostat, and gastric emptying was assessed for 70 min after the ingestion of 500 ml of water using real-time ultrasonography. Results were as follows. (1) Patients showed a significantly longer half-time of gastric emptying than controls (30.03 +/- 8.20 vs. 23.07 +/- 4.67 min; P < 0.001). The sensation thresholds were significantly lower in patients than in controls based not only on pressure but on volume. However, there was no difference in gastric compliance between patients and controls. (2) The half-time of gastric emptying was correlated with various thresholds of sensation based on the volume (perception, r = -0.52, P < 0.005; discomfort, r = -0.54, P < 0.005; pain, r = -0.58, P < 0.005; maximal tolerance, r = -0.42, P < 0.005). But there was no significant correlation between gastric emptying and sensation thresholds based on pressure. Delayed gastric emptying and/or gastric hypersensitivity are present in more than 50% of FD patients. The coexistence of these two abnormalities is more common than the single impairment. There is a correlation between gastric emptying and visceral sensation to gastric distention in patients with FD.     

Impact of coexisting irritable bowel syndrome on symptoms and pathophysiological mechanisms in functional dyspepsia

Epidemiological studies suggest considerable overlap between functional dyspepsia (FD) and irritable bowel syndrome (IBS). AIM: The aim of the present study was to investigate whether coexisting IBS is also associated with symptom pattern or pathophysiology in FD. METHODS: In 309 consecutive FD patients (207 women, age 42 +/- 0.8 yr), questionnaires were used to assess the dyspepsia symptom pattern and the Rome II criteria for IBS. The overall symptom severity was calculated adding the severity score (0-3, 0 = absent, 3 = severe) of eight dyspepsia symptoms. All patients underwent Helicobacter pylori testing, gastric barostat to determine sensitivity to distention and accommodation to a meal, and gastric emptying breath test. RESULTS: Fifty-four percent of the patients had FD alone, whereas 46% had FD + IBS. FD + IBS patients were more likely to be female (75%vs 60%, p < 0.01) and to have a greater weight loss (5.4 +/- 0.6 vs 3.5 +/- 0.4 kg, p < 0.05). Coexisting IBS did not increase the risk of having any of the dyspeptic symptoms but the overall symptom severity was significantly higher in FD + IBS (12.4 +/- 0.4 vs 9.8 +/- 0.3, p < 0.01). FD + IBS patients had a lower threshold for first perception (2.9 +/- 0.3 vs 3.8 +/- 0.3 mmHg, p < 0.05) and for discomfort (7.9 +/- 0.4 vs 9.5 +/- 0.5 mmHg, p < 0.05) and a greater prevalence of hypersensitivity to gastric distention (44%vs 28%, p < 0.05). Gastric emptying, accommodation to a meal, and prevalence of H. pylori infection did not differ in the two groups. CONCLUSION: About half of the FD patients fulfill the Rome II criteria for IBS. FD + IBS is more prevalent in female patients and is associated with a higher weight loss, with greater overall symptom severity, and with hypersensitivity to distention.     

Dyspepsia: organic versus functional

Dyspepsia is the medical term for difficult digestion. It consists of various symptoms in the upper abdomen, such as fullness, discomfort, early satiation, bloating, heartburn, belching, nausea, vomiting, or pain. The prevalence of dyspepsia in the western world is approximately 20% to 25%. Dyspepsia can be divided into 2 main categories: "organic" and "functional dyspepsia" (FD). Organic causes of dyspepsia are peptic ulcer, gastroesophageal reflux disease, gastric or esophageal cancer, pancreatic or biliary disorders, intolerance to food or drugs, and other infectious or systemic diseases. Pathophysiological mechanisms underlying FD are delayed gastric emptying, impaired gastric accommodation to a meal, hypersensitivity to gastric distension, altered duodenal sensitivity to lipids or acids, altered antroduodenojenunal motility and gastric electrical rhythm, unsuppressed postprandial phasic contractility in the proximal stomach, and autonomic nervous system-central nervous system dysregulation. Pathogenetic factors in FD are genetic predisposition, infection from Helicobacter pylori or other organisms, inflammation, and psychosocial factors. Diagnostic evaluation of dyspepsia includes upper gastrointestinal endoscopy, abdominal ultrasonography, gastric emptying testing (scintigraphy, breath test, ultrasonography, or magnetic resonance imaging), and gastric accommodation evaluation (magnetic resonance imaging, ultrasound, single-photon emission computed tomography, and barostat). Antroduodenal manometry can be used for the assessment of the myoelectrical activity of the stomach, whereas sensory function can be evaluated with the barostat, tensostat, and satiety test. Management of FD includes general measures, acid-suppressive drugs, eradication of H. pylori, prokinetic agents, fundus-relaxing drugs, antidepressants, and psychological interventions. This review presents an update on the diagnosis of patients presenting with dyspepsia, with an emphasis on the pathophysiological and pathogenetic mechanisms of FD and the differential diagnosis with organic causes of dyspepsia. The management of uninvestigated and FD, as well as the established and new pharmaceutical agents, is also discussed.     

Comparison of Ileoanal Pouch and Rectal Function Measured by Barostat

The aim of this study was to compare pouch and rectal sensory and motor characteristics and to assess the influence of a meal on pouch tone and motility. Fifteen patients with an ileoanal J-pouch, with adequate pouch function and 12 healthy controls were studied. Visceral compliance was assessed using an electronic barostat by a pressure distension procedure, during which also sensitivity was scored by visual analog scales (VAS). The response to a meal was assessed during set pressure. Pouch and rectal compliance were not significantly different (9.3 ± 0.7 vs 10.6 ± 1.1 ml/mm Hg). VAS score for urge at 28 mm Hg was reduced in patients: 2.4 ± 0.5 cm vs 4.7 ± 0.9 cm in controls (P < 0.05). The postprandial decrease in intra-bag volume was more pronounced in patients (44 ± 11%) than in controls (9 ± 6%, P < 0.01). Postprandial phasic contractions were also more pronounced in patients. In conclusion, compliance is not significantly different between ileoanal pouch and rectum; differences in sensitivity reach significance only at high pressure. Significant differences were especially observed in the postprandial state with an increase in tone and frequency of phasic contractions in pouch patients.     

Influence of gender on proximal gastric motor and sensory function

OBJECTIVE: Gender-related differences have been demonstrated with regard to GI motility: gallbladder contraction, colonic transit, and gastric emptying are delayed in women. It is not known whether gender influences proximal gastric motility and perception. METHODS: We have studied the influence of gender on proximal gastric motility and perception under fasting and postprandial conditions by retrospective analysis of data obtained in 99 healthy volunteers (42 men, 57 women) who participated in barostat studies performed according to standardized protocols at the Leiden University Medical Center (Leiden, The Netherlands) between 1996 and 2000. RESULTS: Minimal distending pressure (MDP) was significantly higher in women than in men (respectively, 6.8+/-0.2 vs 5.5+/-0.2 mm Hg; p < 0.001). During stepwise pressure distensions pressure-volume curves were similar in both sexes after correction for MDP, whereas perception of fullness and abdominal pressure increased significantly (p < 0.05) more rapidly in women. Before the meal intragastric volumes (at MDP + 2 mm Hg) did not differ between sexes. After the meal gastric relaxation in the first 30 min did not differ in women and men (respectively, 186+/-23 ml and 140+/-32 ml). However, from 30 until 90 min after the meal a significantly (p < 0.05) delayed return of intragastric volume to basal was seen in women. Perception of postprandial nausea was significantly (p < 0.01) increased in women. Perception of postprandial fullness remained increased for a longer period of time in women. CONCLUSIONS: Proximal gastric motility and perception are influenced by gender. Gender-related differences in postprandial proximal gastric motility and perception should be taken into account in barostat studies comparing patients with controls.     

The origin of symptoms on the brain-gut axis in functional dyspepsia

It was hypothesized that symptoms in functional dyspepsia are originated by an altered mechanism at the brain-gut axis (one or several) in the process of gastric accommodation to a meal. To test the key mechanisms potentially involved in symptomatic gastric accommodation, the sensorial responses (on a 0-10 perception score) and the gastric tone responses (by electronic barostat) to either gastric accommodation (n = 10) or to cold stress (n = 10) were measured in 20 patients with functional dyspepsia and 20 healthy controls. The mechanical accommodation of the stomach to gastric distention (compliance) was similar in patients (52 +/- 8 mL/mm Hg) and controls (57 +/- 6 mL/mm Hg). However, isobaric gastric distention elicited more upper abdominal discomfort in dyspeptics than in controls (perception scores, 4.7 +/- 0.9 vs. 1.1 +/- 0.5, respectively; mean +/- SE; P less than 0.005). Cold stress induced a similar gastric relaxatory response in dyspeptics and controls (delta vol, 145 mL +/- 40 mL vs. 141 mL +/- 42 mL, respectively); hand perception (scores, 8.3 +/- 0.4 vs. 7.9 +/- 0.4, respectively) and autonomic responses were also similar. It is concluded that an abnormal afferent sensorial pathway (altered gastric perception) may be a major mechanism of symptom production in functional dyspepsia.     

Regional cerebral blood flow during gastric balloon distention in functional dyspepsia

BACKGROUND & AIMS: Hypersensitivity to proximal gastric distention as a result of abnormal central nervous system processing of visceral stimuli is a possible pathophysiologic mechanism in functional dyspepsia (FD). Increasing evidence suggests involvement of both lateral and medial pain systems in normal visceral sensitivity and aberrant brain activation patterns in visceral hypersensitivity. We hypothesized that there is involvement of aberrant brain activation in FD with hypersensitivity to gastric distention. Our aim was to investigate regional cerebral blood flow during painful proximal gastric distention in hypersensitive FD. METHODS: Brain (15)O-water positron emission tomography was performed in 13 FD patients with symptoms of gastric hypersensitivity during 3 conditions: no distention, sham distention, and isobaric distention to unpleasant or painful sensation. Pain, discomfort, nausea, and bloating during maximal distention were rated on visual analogue scales. Data were analyzed using statistical parametric mapping. RESULTS: The threshold for painful distention was 6.6 +/- 3.8 mm Hg greater than the minimal distending pressure. At the corrected P level of less than .05, subtraction analysis (painful distention - no distention) showed activations in bilateral gyrus precentralis, bilateral gyrus frontalis inferior, bilateral gyrus frontalis medialis, bilateral gyrus temporalis superior, bilateral cerebellar hemisphere, and left gyrus temporalis inferior. Sham distention minus no distention showed no activations. CONCLUSIONS: Similar to healthy volunteers, proximal stomach distention in FD activates components of the lateral pain system and bilateral frontal inferior gyri, putatively involved in regulation of hunger and satiety. In hypersensitive FD, these activations occur at significantly lower distention pressures. In contrast to findings in normosensitivity, none of the components of the medial pain system were significantly activated.     

Does Helicobacter pylori infection increase gastric sensitivity in functional dyspepsia?

The role of Helicobacter pylori infection in the pathogenesis of functional dyspepsia is debated. It is known that a substantial fraction of dyspeptic patients manifest a low discomfort threshold to gastric distension. This study investigated the symptomatic pattern in 27 H pylori positive and 23 H pylori negative patients with chronic functional dyspepsia, and potential relations between infection and gastric hyperalgesia. Specific symptoms (pain, nausea, vomiting, bloating/fullness, early satiety) were scored from 0 to 3 for severity and frequency (global symptom scores: 0-15). The mechanical and perceptive responses to gastric accommodation were evaluated with an electronic barostat that produced graded isobaric distensions from 0 to 20 mm Hg in 2 mm Hg steps up to 600 ml. Gastric compliance (volume/pressure relation) and perception (rating scale: 0-10) were quantified. Standard gastrointestinal manometry and recorded phasic pressure activity at eight separate sites during fasting and postprandially were also assessed. H pylori positive and H pylori negative patients manifested similar severity and frequency of specific symptoms and global symptom scores (mean (SEM)) (severity: 9.5 (2.0) v 9.0 (2.1); frequency: 10.8 (2.0) v 9.7 (2.2)). No differences were seen either in gastric compliance (53 (4) ml/mm Hg v 43 (3) ml/mm Hg) or in gastric perception of distension (slope: 0.50 (0.05) v 0.53 (0.06)). Postprandial antral motility was significantly decreased in H pylori positive patients (two hours motility index: 10.4 (0.6) v 12.6 (0.5); p < 0.05). It is concluded that H pylori infected patients with functional dyspepsia present no distinctive symptoms by comparison with H pylori negative counterparts and H pylori infection is associated with diminished postprandial antral motility but it does not increase perception of gastric distension.     

Role of tension receptors in dyspeptic patients with hypersensitivity to gastric distention

BACKGROUND & AIMS: Studies in health have shown that tension-sensitive mechanoreceptors mediate sensitivity to gastric distention. A role for these mechanoreceptors in perception or symptoms in hypersensitive functional dyspepsia (FD) has not been established. Tension-sensitive mechanoreceptors are activated during phasic contractions and inactivated during gastric relaxation. The aim of the present study was to investigate whether hypersensitive FD patients perceive spontaneous changes in fundic wall tension and whether fundus-relaxing drugs decrease sensitivity to gastric distention and meal-related symptoms. METHODS: Fifty patients were selected after a barostat study established gastric hypersensitivity. In 12 patients, an intragastric balloon was inflated with a fixed volume just below perception thresholds and patients were asked to indicate changes in perception on a keypad, and the relationship between perception and contractions was analyzed. In 20 patients, we studied the influence of the fundus-relaxing drug sumatriptan on sensitivity to gastric distention. In, respectively, 10 and 8 patients, we studied the influence of the fundus-relaxing drugs sumatriptan and clonidine on meal-related symptoms. RESULTS: The majority of patients had a statistically significant association between perception and phasic isovolumetric contractions. Pretreatment with sumatriptan increased both pressures and volumes needed to induce first perception and discomfort. Pretreatment with sumatriptan and clonidine both significantly decreased meal-induced symptoms. CONCLUSIONS: Patients with hypersensitivity to gastric distention perceive isovolumetric phasic contractions of the proximal stomach. Fundus-relaxing drugs decrease sensitivity to gastric distention and decrease meal-induced symptoms in these patients. The findings are compatible with involvement of tension mechanoreceptors in symptom generation in hypersensitive FD.     

Compliance of the proximal stomach and dyspeptic symptoms in patients with type I diabetes mellitus

In the present study the function of the proximal stomach and its role in eliciting dyspeptic symptoms were evaluated in patients with diabetes mellitus. Eight type I diabetics with cardiovascular autonomic neuropathy and dyspeptic symptoms, and 10 healthy volunteers were studied using an electronic barostat device connected to a intragastric bag. The intragastric bag was inflated and deflated by stepwise pressure increments, creating pressurevolume curves. During the experiment the blood glucose concentrations were maintained within the euglycemic range in the diabetics. The volume-pressure curves showed a larger volume during the pressure increase in the diabetics than in the controls (P<0.01). This resulted in a significant difference in compliance (dV/dP), 57.2±4.2 ml/mm Hg in diabetics and 43.7±3.5 ml/MM Hg in controls (P<0.014). The volume-pressure curves during deflation of the intragastric balloon were different from the curves during inflation, creating a hysteresis loop. The area between the inflation and deflation curves was 827 ml/mm Hg in diabetics and 627 ml/mm Hg in the controls (P=0.21). Gastric distension induced more upper gastrointestinal sensations in the patients than in the volunteers: nausea (P<0.002), bloating (P<0.003), upper abdominal pain (P<0.001). In conclusion: this study showed that the compliance of the proximal stomach is increased in diabetic patients with autonomic neuropathy and gastrointestinal symptoms. This abnormality, probably due to autonomic neuropathy, is associated with increased symptom generation during gastric distension.     

Effects of duodenal lipids on gastric sensitivity and relaxation in patients with ulcer-like and dysmotility-like dyspepsia

BACKGROUND/AIMS: Functional dyspepsia (FD) according to Rome II is divided into ulcer-like dyspepsia (ULD) and dysmotility-like dyspepsia (DLD). The rationale behind this is the assumption that the underlying pathophysiology is different, but this is largely unexplored. Our aim was to elucidate the differences in gastric sensorimotor function in these subgroups of FD. 13 healthy controls (HC) and 20 patients with FD, 10 ULD and 10 DLD, were included. METHODS: A feeding tube was placed fluoroscopically in the proximal duodenum and a barostat balloon was placed in the proximal stomach. Sensory thresholds to gastric distention for first sensation, bloating and discomfort were assessed before and after duodenal lipid infusion (2 kcal/min, 60 min). RESULTS: Volume changes in the balloon were recorded as a measure of gastric tone. In FD patients, sensory thresholds in the fasting state were significantly lower than in HC, mostly due to gastric hypersensitivity in ULD. After lipid infusion, 95% of FD patients fell outside the normal range of HC for first sensation, bloating and/or discomfort, compared with 65% in the fasting state. Patients with ULD but not DLD had impaired fundic relaxation after duodenal lipids compared with HC. CONCLUSIONS: Investigating gastric sensorimotor function after duodenal lipid infusion, FD patients can accurately be differentiated from HC. Impaired fundic relaxation seems to be more common in patients with ULD.