Ambulatory small intestinal motility in 'diarrhoea' predominant irritable bowel syndrome.

Dysmotility of the duodenum and proximal jejunum has been reported in patients with irritable bowel syndrome. This study extended these findings by recording fasting ambulatory motility from electronic strain gauge sensors sited in the jejunum and ileum of eight diarrhoea predominant irritable bowel syndrome patients and 12 healthy controls. During the day, periodicity of migrating motor complexes mean (SEM) did not differ between patients (92 (10) min) and controls (85 (7) min). At night, periodicity was shorter in both patients and controls, and the daytime dominance of phase II was replaced by phase I. In both groups, aboral progression of phase III fronts was associated with a slowing of propagation velocity and maximum contractile rate, but an increase in mean amplitude of contraction. Discrete clustered contractions were seen in seven patients and 10 controls occupying 14 and 16% of daytime phase II activity, respectively. Pain episodes were not associated with any specific motility patterns. Despite the lack of motility differences between the two groups, orocaecal transit time in the irritable bowel syndrome patients was shorter at 57 (9) min than in the controls, 82 (6) min (p < 0.05). This ambulant study has failed to show any abnormalities of fasting small intestinal motility that might distinguish diarrhoea predominant irritable bowel syndrome patients from healthy controls.     

Visceral perception in irritable bowel syndrome

We wished to determine if visceral perception in the rectum and stomach is altered in patients with irritable bowel syndrome and to evaluate the effects on visceral sensation of 5-HT₃ receptor blockade. Twelve community patients with diarrhea-predominant irritable bowel syndrome and 10 healthy controls were studied in a double-blind, randomized, placebo-controlled study. Using two barostats, the stomach and rectum were distended, with pressure increments of 4 mm Hg, from 10 to 26 mm Hg; visceral perception was measured on an ordinal scale of 0–10. Personality traits were measured using standard psychological methods, and somatic pain was evaluated by immersion of the nondominant hand in cold water. The effect of 5-HT₃ antagonism was tested with a single intravenous dose of ondansetron at 0.15 mg/kg. Gastric perception was higher in irritable bowel syndrome, but rectal distension was perceived similarly in irritable bowel syndrome and controls. Pain tolerance to cold water was also similar in irritable bowel syndrome and controls. Ondansetron induced rectal relaxation and increased rectal compliance but did not significantly alter gastric compliance or visceral perception. Psychological test scores were similar in patients and controls. We conclude that in this group of psychologically normal patients with irritable bowel syndrome, who were not chronic health-care seekers, visceral perception was normal. Ondansetron did not alter gut perception in health or in irritable bowel syndrome.This work was supported in part by grants AG09440, DK32121, and RR585 from the National Institutes of Health.     

肠易激综合征患者胃窦十二指肠移行性复合波的研究

目的　观察肠易激综合征 (IBS)患者的胃窦十二指肠移行性复合波 (MMC)变化 ,并分析其与症状之间的关系。方法　 2 0名健康对照者及 17例IBS患者 (8例腹泻型 ,9例便秘型 )禁食 6h以上 ,用瑞典CTD公司生产的灌注式小肠测压管记录至少 2个完整的MMC周期 ,之后给每位受试者服标准餐 ,用餐时间为 15～ 30min ,继续观察餐后波 1～ 2h。结果　腹泻型IBS患者消化间期MMC周期短、Ⅲ相波幅高、时程长 ,便秘型IBS患者MMC周期长、时程短。IBS患者MMCⅡ相小肠离散丛集簇(DCC)波的时程延长 ,但腹泻组与便秘组之间差异无显著性 (P >0 .0 5 )。IBS腹泻组的Ⅱ、Ⅲ相的运动指数高于便秘组和对照组。进餐后IBS患者小肠运动形式无明显改变。结论　IBS患者消化间期MMC的各相时程及波幅异常与IBS症状密切相关 ,DCC可能与IBS腹泻、便秘症状发生的关系较小 ,IBS患者餐后胃肠运动无明显异常 ,可能与病例数较少有关 ,有待今后增加例数进一步观察     

Colon motility and psychological traits in irritable bowel syndrome

Digestive Diseases and Sciences -     

Lipid-induced intestinal gas retention in irritable bowel syndrome

BACKGROUND & AIMS: We hypothesized that lipids, which induce various motor and sensory effects on the gut, modulate intestinal gas dynamics and that alteration of this regulatory mechanism may result in impaired gas transit in patients with irritable bowel syndrome (IBS). METHODS: In 45 healthy subjects and 30 patients with IBS, evacuation of gas infused into the jejunum (at 12 mL/min) was measured for 2 hours. The effect of simultaneous duodenal perfusion of lipids at 0 kcal/min (saline), 0.5 kcal/min, and 1 kcal/min was tested in groups of 15 subjects each. RESULTS: In healthy subjects, duodenal lipids at 1 kcal/min but not at 0 kcal/min or 0.5 kcal/min produced significant gas retention (281 +/- 53 mL vs. 22 +/- 64 mL at 0 kcal/min and -65 +/- 72 mL at 0.5 kcal/min; P < 0.05 for both). Patients with IBS exhibited gas retention during saline perfusion (259 +/- 85 mL at 0 kcal/min; P < 0.05 vs. healthy subjects) and were hypersensitive to duodenal lipids (505 +/- 61 mL retention at 0.5 kcal/min; P < 0.05 vs. saline and vs. healthy subjects). The "gas plus lipids" challenge test discriminated patients with 100% sensitivity and 93% specificity. CONCLUSIONS: Physiologic concentrations of intestinal lipids exert an inhibitory control on intestinal gas transit, and this mechanism is up-regulated in patients with IBS. Hence, impaired gas propulsion, shown by the gas challenge test, may be useful as a diagnostic test if replicated in a larger series of patients.     

肠易激综合征患者胆囊运动功能的研究

目的 了解肠易激综合征患者的胆囊运动功能情况,协助肠易激综合征的治疗。方法 我们通过对健康志愿者(对照组)和肠易激综合征患者(IBS组)用核素显相测定胆囊排空功能。结果 IBS组23例中有13例(56.5％13／23),对照组16例中有4例(25％4／16),餐后1小时胆囊排空指数(GBEF)降低,两组比较差异有显著性(P<0.01)。餐后30、40、50和60minGBEF IBS组均低于对照组,差异有非常显著性(P<0.01)。结论 IBS组胆囊排空率下降,排空功能不良。在治疗肠易激综合征同时予利胆促动力剂治疗。     

Altered small bowel motility in irritable bowel syndrome is correlated with symptoms

The pathogenesis of irritable bowel syndrome (IBS) has been related more to dysmotility of the colon than to abnormalities of the small intestine. To look for small bowel abnormalities, we recorded ultraluminal pressures in 16 patients with IBS. All patients complained of abdominal pain, and diarrhea (n = 8) or constipation (n = 8) were also prominent symptoms. Comparable studies were performed on 16 age-matched controls. The observations include diurnal and nocturnal fasting recordings and the response to a fatty meal. Periodicities of the interdigestive migrating myoelectric complexes were shorter in IBS (p less than 0.05); this was due to much shorter diurnal cycles in patients with diarrhea (77 +/- 10 min) than those with constipation (118 +/- 15 min) or controls (113 +/- 10 min, both p less than 0.05). All groups exhibited circadian changes, with nocturnal cycles being more frequent. Two specific patterns of small bowel motor activity were more common in IBS--ileal propulsive waves and clusters of jejunal pressure activity (both p less than 0.05 compared to controls). Moreover, cramping abdominal pain was usually noted in IBS when ileal motility was propulsive; jejunal bursts were also sometimes associated with abdominal symptoms. We conclude that motility of the small intestine is modified in some patients with IBS and that certain motor patterns are related to their symptoms.     

Effect of a tricyclic antidepressant on small intestinal motility in health and diarrhea-predominant irritable bowel syndrome

Antidepressants are used in irritable bowel syndrome (IBS) and may have effects on the gut independent of improving mood. We have investigated the actions of a tricyclic antidepressant on small intestinal motor function in eight healthy volunteers and in six patients with diarrhea-predominant IBS. Fasting ambulatory motility was recorded from six small intestinal sites for 16–18 hr while on no drug (baseline) and while taking imipramine for five days. Orocecal transit time (OCTT) was measured by lactulose hydrogen breath test, during baseline and imipramine administration. Imipramine did not alter migrating motor complex periodicity, but slowed jejunal phase III propagation velocity in controls from 7.5±1.1 to 3.6±0.5 cm/min (P<0.01) and in IBS from 7.8±0.6 to 4.4±0.5 cm/min (P<0.0001). Phase III duration at each site was increased, and total recorded phase III was greater during imipramine than baseline studies. Imipramine increased the amplitude of phase III contractions. There was no effect of imipramine on non-phase-III motility index or discrete clustered contractions. Imipramine prolonged OCTT from 73±6 min to 97±8 min in controls (P<0.05) and from 61±9 min to 89±8 min in IBS (P<0.05). Although OCTT was shorter in this IBS group, no motility differences were seen between controls and IBS. This demonstration that a tricyclic antidepressant can modify small intestinal motor function in health and in IBS supports the view that these drugs may have therapeutic actions in IBS unrelated to mood improvement.This work was supported by the Priory Hospitals Group.     

Sigmoid motility in diverticular disease and the irritable bowel syndrome.

Intraluminal pressures were measured with four open ended, water perfused tubes in the fasting state and after a standard liquid meal (400 KCal, 375 ml, protein 15 g, carbohydrate 55 g, lipid 13.4 g) in six patients with sigmoid diverticular disease, 20 with the irritable bowel syndrome and in 13 controls. The pressure sensors were positioned in the true sigmoid colon at colonoscopy at 25, 35, 45, and 55 cm from the anus. Colonic pressures were significantly higher in diverticular disease than in controls before (p less than 0.02) and after the meal (p less than 0.002), some pressure amplitudes exceeding 300 cm H2O. Patients with the irritable bowel syndrome had lower (p less than 0.05) pressures than controls before the meal. Postprandial sigmoid pressures were within the mean +/- 2 SD of controls in 10, above in two and below in eight patients with the irritable bowel. Hypercontractility of the sigmoid colon in the irritable bowel syndrome was not confirmed under the conditions of this study. The association between sigmoid diverticulosis and high intraluminal pressures is confirmed.     

Microinflammation in the intestinal mucosa and symptoms of irritable bowel syndrome

Journal of Gastroenterology - Potential etiological mechanisms of irritable bowel syndrome (IBS) have been reported, and emerging data suggest that immune activation is present in a major subset of...     

Alterations in rectal sensitivity and motility in childhood irritable bowel syndrome

BACKGROUND & AIMS: Children with chronic abdominal pain have a heterogeneous clinical presentation, but no organic cause can be identified in most of them. Some children present with symptoms of irritable bowel syndrome (IBS). We hypothesized that visceral hypersensitivity and motor abnormalities may be underlying mechanisms in these children. METHODS: Rectal sensation and rectal contractile response to a meal were studied in 8 children with IBS and 8 children with functional abdominal pain (FAP) and were compared with those of 9 healthy volunteers (HVs). RESULTS: The threshold for pain, but not that for first sensation and urge to defecate, was significantly decreased in IBS patients (6 +/- 1 mm Hg) compared with FAP patients and HVs (17 +/- 1 and 22 +/- 2 mm Hg, respectively). In HVs and patients with FAP, ingestion of a meal induced a decrease in rectal volume with an early and late component. This motor pattern was absent in children with IBS. In IBS patients, no rapid volume waves were observed during fasting in contrast to FAP patients (2.7 +/- 0.3/10 min) and HVs (1.8 +/- 0.5/10 min). CONCLUSIONS: Children fulfilling the Rome II criteria for IBS have a significantly lowered threshold for pain and a disturbed contractile response to a meal. Comparable to results reported in adults, sensory and motor abnormalities might play a pathophysiologic role in childhood IBS.     

不同亚型肠易激综合征患者肠道菌群改变的观察

[目的]观察不同亚型肠易激综合征(IBS)患者肠道菌群的改变,探讨IBS的发病机制。[方法]按照罗马Ⅲ标准选取腹泻型、便秘型及混合型IBS患者各20例,另选健康人20例作对照组,观察各组粪便菌群密集度、菌群多样性、细菌比例和菌群培养检测结果,并对比分析。[结果]腹泻组菌群密集度明显降低(P0.05),且菌群多样性也明显低于对照组(P0.05);与对照组比较,各亚型IBS患者革兰阳性杆菌菌群比例均明显下降(P0.05)、革兰阴性杆菌比例明显升高(P0.05),且腹泻组与便秘组、混合组之间也有显著差别(P0.05);腹泻组、混合组革兰阳性球菌、大肠杆菌比例均较对照组有显著增高(P0.05);腹泻组与便秘组比较亦有明显差别(P0.05);混合组肠球菌与对照组比较差异有统计学意义(P0.05);各亚型IBS患者双歧杆菌、乳杆菌均有减少,与对照组相比差异有统计学意义(P0.05)。[结论]腹泻型、便秘型及混合型IBS患者均存在肠道菌群失调,以腹泻型最为明显,菌群失调应该是其发病的主要因素之一。     

肠易激综合征和肠道感染关系研究进展

肠易激综合征(irritable bowel syndrome,IBS)以前被认为是心理学上的改变以及肠道动力的改变和感觉敏感性的增加.但是,最近一些研究提示肠道感染和IBS也有密切关系,本文就此做一综述.     

加强对感染后肠易激综合征的研究

肠易激综合征(IBS)是一组以排便后缓解或减轻的腹痛或腹部不适为主要特征的肠道综合征,根据大便习惯分为腹泻型、便秘型、混合型和不确定型。IBS是一种多因素疾病,其发病与精神心理、感染、食物等多种因素有关。人群发病率在10%~15%。感染后肠易激综合征(PI-IBS)是其中的一种亚     

Enhanced preattentive central nervous system reactivity in irritable bowel syndrome

OBJECTIVE: Irritable bowel syndrome (IBS) is a common functional disorder characterized by enhanced perceptual sensitivity and hypervigilance toward afferent signals from the viscera. We hypothesize that the increased responsiveness of IBS patients is a generalized phenomenon applying to stimuli other than visceral and attempt to demonstrate increased responsiveness to sounds as measured by the P1 scalp potential. METHODS: Event-related potentials were recorded from IBS patients and control subjects in an auditory task requiring detection of rare pitch targets in a designated ear. Visual words served as targets in an additional block. RESULTS: Compared to control subjects, IBS patients displayed a robust increase in the amplitude of the P1 scalp potential elicited by both attended and unattended sounds. CONCLUSIONS: Enhanced P1 indicates preattentive central nervous system dishabituation in response to repeated sounds. A generalized preattentive increase in central nervous system reactivity may be a feature that IBS shares with several anxiety disorders that frequently co-occur in these patients.