Irritable Bowel Syndrome Group Research Articles

Abnormal regional homogeneity in patients with irritable bowel syndrome: A resting-state functional MRI study.

Task-related brain imaging research has implicated abnormal central processing of visceral sensation in irritable bowel syndrome (IBS). However, how brain function of IBS patients is altered during resting-state remains to be determined. We investigated spontaneous brain activity of patients with IBS using regional homogeneity (ReHo) analysis in resting-state functional magnetic resonance imaging (rs-fMRI). Thirty-one patients with diarrhea-predominant IBS and 32 age- and sex- matched healthy controls underwent clinical assessments and rs-fMRI scanning. ReHo maps were acquired by calculating the Kendall's coefficient of concordance and compared between the IBS group and the control group. The effects of psychological disturbance on group differences were assessed by including anxiety and depression levels as covariates in the statistical analyses. Multiple regression analyses were conducted to examine the relationship between ReHo values and disease duration, symptom severity, and pain intensity. Compared with controls, IBS patients showed increased ReHo in the postcentral gyrus and thalamus and decreased ReHo in the anterior cingulate cortex and prefrontal cortex. The inclusion of anxiety and depression as covariates did not alter ReHo differences between the two groups. Furthermore, significant correlations were found between clinical indices and ReHo values in some brain regions in the IBS group. IBS patients have abnormal local synchronization of spontaneous brain activity in regions involved in visceral afferent processing, emotional arousal, and cognitive modulation. Combining rs-fMRI and ReHo analysis seems to be a valuable approach to investigate the neural basis of IBS.

Blastocystis sp. in Irritable Bowel Syndrome (IBS)--Detection in Stool Aspirates during Colonoscopy.

Blastocystis is one of the most common gut parasites found in the intestinal tract of humans and animals. Its' association with IBS is controversial, possibly as a result of irregular shedding of parasites in stool and variation in stool detection. We aimed to screen for Blastocystis in colonic stool aspirate samples in adult patients with and without IBS undergoing colonoscopy for various indications and measure the interleukin levels (IL-8, IL-3 and IL-5). In addition to standard stool culture techniques, polymerase chain reaction (PCR) techniques were employed to detect and subtype Blastocystis. All the serum samples collected were subjected for ELISA studies to measure the interleukin levels (IL-8, IL-3 and IL-5). Among 109 (IBS n = 35 and non-IBS n = 74) adults, direct stool examination and culture of colonic aspirates were initially negative for Blastocystis. However, PCR analysis detected Blastocystis in 6 (17%) IBS and 4 (5.5%) non-IBS patients. In the six positive IBS patients by PCR method, subtype 3 was shown to be the most predominant (3/6: 50%) followed by subtype 4 (2/6; 33.3%) and subtype 5 (1/6; 16.6%). IL-8 levels were significantly elevated in the IBS Blasto group and IBS group (p<0.05) compared to non-IBS and non-IBS Blasto group. The level of IL-3 in were seen to be significantly higher in than IBS Blasto group and IBS group (p<0.05) compared to non-IBS. Meanwhile, the IL-5 levels were significantly higher in IBS Blasto group (p<0.05) compared to non-IBS and non-IBS Blasto group. This study implicates that detecting Blastosystis by PCR method using colonic aspirate samples during colonoscopy, suggests that this may be a better method for sample collection due to the parasite’s irregular shedding in Blastocystis-infected stools. Patients with IBS infected with parasite showed an increase in the interleukin levels demonstrate that Blastocystis does have an effect in the immune system.

Symptom features of irritable bowel syndrome complicated with depression

Objective To improve the ability of early recognition of psychological disorders in irritable bowel syndrome (IBS) patients by analyzing somatic and digestive tract symptoms of IBS patients complicated with depression. Methods From May to October 2014, 102 out-patients with IBS were enrolled who completed the questionnaire and were followed-up. Another 102 gender and age matched individual who received check-up were set as healthy controls. The detailed clinical data of all IBS patients were collected. The scores of Hamilton depression scale (HAMD), digestive symptom questionnaire, somatic symptom questionnaire and irritable bowel syndrome symptom severity score (IBS-SSS) were evaluated in the IBS patients, and HAMD was evaluated in healthy controls. The t test or chi-square test was performed for statistical analysis. Results HAMD score of the IBS group was 19.1±17.0, which was higher than that of control group (3.2±2.9; t=8.966, P<0.05). Among the 102 IBS patients, 58 were complicated with depression (56.9%) and 44 (43.1%) without depression. Among the IBS patients complicated with depression, 75.9% (44/58) were overlapped with gastrointestinal symptoms, which was higher than that of patients without depression (34.1%, 15/44), and the difference was statistically significant (χ2=17.902, P<0.01). The typical somatic symptoms of IBS patients complicated with depression were headaches, dizziness, insomnia, palpitations, chest pain, and chest tightness.The results of IBS-SSS indicated that scores of duration of abdominal pain, bloating degree and the impacts on quality of life in IBS patients complicated with depression were 78.1±28.7, 53.7±17.9 and 69.4±19.7, which were significantly higher than those of IBS patients without depression (34.7±16.6, 37.7±12.5 and 32.4±12.7). The score of defecation satisfaction of IBS patients complicated with depression was 43.7±16.4, which was lower than that of patients without depression (55.0±20.3), and all the differences were statistically significant (t=-8.930, -2.326, -8.913 and -2.344, all P<0.05). Conclusions The somatic and overlapped digestive symptoms of IBS patients complicated with depression are obvious and complicated. For IBS patients with obvious extra symptoms, mental disorders should be taken into consideration. On the basis of the treatment of IBS symptoms, the treatment of psychological disorders are also needed. Key words: Irritable bowel syndrome; Depression; Somatic syndrome

Blastocystis specific serum immunoglobulin in patients with irritable bowel syndrome (IBS) versus healthy controls

BackgroundBlastocystis species are common enteric human parasites and carriage has been linked to Irritable Bowel Syndrome (IBS), particularly diarrhoea-predominant IBS. The spectrum of immune reactivity to Blastocystis proteins has been reported previously in symptomatic patients. We investigated differences in serum immunoglobulin profiles between patients with IBS, both positive and negative for Blastocystis carriage, and healthy controls (HC).MethodsForty diarrhoea-predominant IBS patients (26 patients positive for Blastocystis sp., 14 negative patients) and forty HC (24 positive, 16 Blastocystis-negative) were enrolled. Age, gender, ethnicity and serum immunoglobulin A (IgA) levels were recorded and faecal specimens were analysed using smear, culture and polymerase chain reaction amplification of ribosomal DNA. Sera were tested in Western blots and the reactivities compared to known targets using monoclonal antibodies Blastofluor® (Blastocystis specific antibody), MAb1D5 (cytopathicto Blastocystis cells), anti-promatrix metalloprotease-9 (anti-MMP-9) and SDS-PAGE zymograms.ResultsLevels of serum IgA were significantly lower in Blastocystis carriers (p < 0.001) but had no relationship to symptoms. Western blots demonstrated serum IgG antibodies specific for Blastocystis proteins of 17,27,37,50,60-65, 75–90, 95–105 and 150 kDa MW. Reactivity to the 27, 50 and 75-95 kDa proteins were found more frequently in the IBS group compared to the HC’s (p < 0.001) and correlation was greater for Blastocystis-positive IBS patients (p < 0.001) than for negative IBS patients (p < 0.05). MAb1D5 reacted with proteins of 27 and 100 kDa, and anti-MMP-9 with 27, 50 and 75-100 kDa proteins. Bands were seen in zymograms around 100 kDa.ConclusionsLow serum IgA levels are associated with Blastocystis carriage. All IBS patients were more likely to demonstrate reactivity with Blastocystis proteins of 27 kDa (likely a cysteine protease), 50 and 75-95 kDa MW compared to HC. The presence of antibodies to these Blastocystis proteins in some Blastocystis-negative subjects suggests either prior exposure to Blastocystis organisms or antibody cross reactivities. The anti-proMMP-9 reaction at 50 and 75–100 kDa and the zymogram result suggest that metalloproteases may be important Blastocystis antigens.Trial registrationAustralian and New Zealand Clinical Trials registry ACTRN: 12611000918921Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-1069-x) contains supplementary material, which is available to authorized users.

Mechanistic understanding of the effects of probiotics in the modulation of abdominal pain: one study at a time.

Mechanistic understanding of the effects of probiotics in the modulation of abdominal pain: one study at a time.

Molecular and cellular mechanisms of tight junction dysfunction in the irritable bowel syndrome.

The pathophysiological mechanisms of the irritable bowel syndrome (IBS), one of the most prevalent gastrointestinal disorders, are complex and have not been fully elucidated. The present study aimed to investigate the molecular and cellular mechanisms of tight junction (TJ) dysfunction in IBS. Intestinal tissues of IBS and non-IBS patients were examined to observe cellular changes by cell chemical tracer electron microscopy and transmission electron microscopy, and intestinal claudin-1 protein was detected by immunohistochemistry, western blot analysis and fluorescence quantitative polymerase chain reaction. Compared with the control group, TJ broadening and the tracer extravasation phenomenon were observed in the diarrhea-predominant IBS group, and a greater number of neuroendocrine cells and mast cells filled with high-density particles in the endocrine package pulp as well as a certain extent of vacuolization were present. The expression of claudin-1 in diarrhea-predominant IBS patients was decreased, while it was increased in constipation-predominant IBS patients. In conclusion, the results of the present study indicated that changes in cellular structure and claudin-1 levels were associated with Tjs in IBS.

Tong Xie Yao Fang relieves irritable bowel syndrome in rats via mechanisms involving regulation of 5-hydroxytryptamine and substance P.

To investigate whether the Chinese medicine Tong Xie Yao Fang (TXYF) improves dysfunction in an irritable bowel syndrome (IBS) rat model. Thirty baby rats for IBS modeling were separated from mother rats (1 h per day) from days 8 to 21, and the rectum was expanded by angioplasty from days 8 to 12. Ten normal rats were used as normal controls. We examined the effects of TXYF on defection frequency, colonic transit function and smooth muscle contraction, and the expression of 5-hydroxytryptamine (5-HT) and substance P (SP) in colonic and hypothalamus tissues by Western blot and RT-PCT techniques in both normal rats and IBS model rats with characterized visceral hypersensitivity. Defecation frequency was 1.8 ± 1.03 in normal rats and 4.5 ± 1.58 in IBS model rats (P < 0.001). However, the defecation frequency was significantly decreased (3.0 ± 1.25 vs 4.5 ± 1.58, P < 0.05), while the time (in seconds) of colon transit function was significantly increased (256.88 ± 20.32 vs 93.36 ± 17.28, P < 0.001) in IBS + TXYF group rats than in IBS group rats. Increased colonic smooth muscle tension and contract frequency in IBS model rats were significantly decreased by administration of TXYF. Exogenous agonist stimulants increased spontaneous activity and elicited contractions of colon smooth muscle in IBS model rats, and all of these actions were significantly reduced by TXYF involving 5-HT and SP down-regulation. TXYF can modulate the activity of the enteric nervous system and alter 5-HT and SP activities, which may contribute to the symptoms of IBS.

Ratio of spleen diameter to red blood cell distribution width: a novel indicator for celiac disease.

Celiac disease (CD) is currently considerably underdiagnosed, setting the need for developing tools to select patients with probability of CD, who warrant further testing. Red blood cell distribution width (RDW) has been shown in previous studies to be a sensitive predictor for CD, but it lacks specificity. Splenic hypotrophy is also noted frequently in celiac patients.Our aim was to evaluate if spleen diameter to RDW ratio can be used as an indicator for CD.We evaluated 15 newly diagnosed CD patients, 52 patients with inflammatory bowel disease, and 35 patients with irritable bowel syndrome (IBS). We evaluated the differences in spleen diameter, RDW, and their ratio among the four groups.Two-thirds of the CD patients had elevated RDW, compared to 9% in the IBS group. A small spleen was seen in 80% of the celiacs, compared to 21.9% in the ulcerative colitis group, 10% in the Crohn disease group, and 9% in the IBS group. A spleen diameter to RDW ratio under 6 had a sensitivity of 73.3% and specificity of 88.5% in predicting CD, with an AUROC of 0.737.Spleen diameter to RDW ratio is a simple, widely available score, which can be used to select adult patients with probability of CD.

Vitamin D Deficiency in Patients with Irritable Bowel Syndrome: Does it Exist?

Vitamin D has been found to be strongly associated with many systemic disorders. There has been an augmented interest within the medical community in vitamin D, especially its deficiency, in various systemic disorders. Although the role of vitamin D deficiency in irritable bowel syndrome (IBS) has not yet been established, studies are underway to clearly establish its role in the disease. The objective of our study was to elucidate and establish the role of vitamin D deficiency in IBS patients compared to a healthy control group. This study is a comparative case control study of vitamin D deficiency in patients with IBS diagnosed with ROME 3 criteria of classification (the third ROME foundation classification) to an age and gender matched healthy control group. The vitamin D level was measured in both cohorts for comparison and the results interpreted statistically. Sixty patients with IBS and 100 healthy individuals were included as test and control groups, respectively, in the study. The mean serum vitamin D level (nmol/L) of IBS patients was compared to the control group. Vitamin D deficiency was detected in 49 patients (82%) in the IBS group and 31 patients (31%) in the control group. There was a statistically significant difference in the mean vitamin D level (p=0.025) between the IBS group and control group. Our study shows that vitamin D deficiency is highly prevalent in patients with IBS and these results seem to have therapeutic implications. Vitamin D supplementation could play a therapeutic role in the control of IBS.

Effect of prolonged stress on the adrenal hormones of individuals with irritable bowel syndrome.

BackgroundThe purpose of this study was to investigate the effect of prolonged stress on the salivary adrenal hormones (cortisol, dehydroepiandrosterone [DHEA], DHEA-sulfate [DHEA-S]) of individuals with irritable bowel syndrome (IBS).MethodsThe participants were female college students, including 10 with IBS and 16 without IBS (control group), who were scheduled for a 2-week teaching practice at a kindergarten. Participants were asked to collect saliva for determining adrenal hormones immediately and 30 min after awakening and before sleep, 2 weeks before the practice, the first week of the practice, the second week of the practice, and a few days after the practice.ResultsRegarding cortisol/DHEA ratio, significantly increased levels were found during the first week of the practice, and a significant interaction between group and time was found; the ratio at 30 min after awakening in the IBS group was higher than that in the control group. For the other adrenal hormone indexes, no significant differences due to the presence of IBS were found.ConclusionsIndividuals with IBS showed an elevated cortisol/DHEA ratio after awakening compared with individuals without IBS, and the elevated ratio peaked under the prolonged stress. The present study suggests that the cortisol effect is dominant in individuals with IBS under prolonged stress.

Visceral abdominal obesity is associated with an increased risk of irritable bowel syndrome.

There are several studies considering obesity as the risk factor for various lower gastrointestinal symptoms. But the relationship between visceral abdominal obesity and the incidence of irritable bowel syndrome (IBS) is not studied yet. The aim of this study was to investigate the association between visceral adipose tissue (VAT) and the risk of IBS. This is a case-control study comparing the VAT area between subjects with IBS (IBS group) and controls without IBS (non IBS group), who underwent abdomen computerized tomography (CT) for routine health checkup from January 2012 to August 2013 in a health promotion center. A telephone survey was retrospectively conducted to diagnose IBS by Rome III criteria. The association between IBS and abdominal obesity was evaluated by measuring VAT, subcutaneous adipose tissue (SAT), VAT/SAT ratio, body mass index (BMI) and waist circumference (WC). The prevalence of IBS was 19.9% (67/336) among all enrolled subjects. In the univariate analysis, VAT area, VAT/SAT ratio, waist circumference, the presence of reflux esophagitis and the ratio of females were significantly higher in the IBS group than in the non IBS group. However, a higher BMI or a higher SAT area is not associated with an increased risk of IBS. In the multivariate analysis, a higher VAT area (odds ratio (OR)=9.42, 95% confidence interval (CI): 2.90-30.64, highest tertile vs. lowest tertile, P=0.001), VAT/SAT ratio (OR=10.15, 95% CI: 3.05-33.58, highest tertile vs. lowest tertile, P=0.001) and waist circumference (OR=7.81, 95% CI: 2.13-28.66, highest tertile vs. lowest tertile, P=0.002) were independently associated with a risk of IBS. Only in the IBS-D group, not in the IBS-C, visceral adiposity was associated with an increased risk of IBS. Visceral adiposity measured by VAT, VAT/SAT, and waist circumference is associated with an increased risk of IBS, especially of IBS-D. However, neither SAT nor BMI are associated with an increased risk of IBS.

Two gastrointestinal conditions with similar symptoms and endoscopic appearance: irritable bowel syndrome and microscopic colitis.

Irritable bowel syndrome (IBS) is a gastrointestinal condition characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any organic cause. This trial investigated the presence of microscopic colitis (MC) and associated factors related to MC in patients diagnosed with IBS. The study group (group I) consisted of 91 consecutive patients diagnosed with IBS based on the Rome III Criteria for whom colonoscopic examination was requested. The control group (group II) had 41 patients diagnosed with IBS considered as eligible for colonoscopic investigation due to specific conditions, and for whom colonoscopic examination was recommended for screening purposes due to a familial history of colon cancer. Clinical data, endoscopic findings, and the effects of the therapy were evaluated. In the diarrhea-predominant IBS group, nine patients (9.89%) were diagnosed with microscopic colitis, seven with lymphocytic colitis (7.69%), and two with collagenous colitis (CC) (2.19%). None of the patients in group II were found to have MC (P = 0.007). There were no diagnoses of MC in the constipation-predominant and mixed type IBS groups. Clinicians should keep MC in mind for patients presenting with diarrhea-predominant IBS symptoms.

Affective Temperaments in Patients with Irritable Colons: A Suspicious Relationship

Objective: There is a growing literature about the relationship between irritable colon and psychiatric symptoms. 'However, to the best of our knowledge, research is limited regarding the relationship between irritable bowel syndrome (IBS) and affective temperaments that are precursors of mood disorders. The aim of this study was, therefore, to investigate whether there is a relationship between affective temperaments and IBS. Methods: This study included 57 patients with irritable colon and 57 healthy controls. Irritable colon was evaluated according to the ROME III criteria. All participants in both groups were given a structured interview for DSM-IV Axis I disorders, and those with any active psychiatric disorder were excluded. Results: Irritable colon patients had significantly higher scores of depressive, anxious and irritable temperaments than healthy controls with a student's t-test. Depressive temperament was related to age and lower education level (p<0.05). Anxious temperament was only related with occupational status of the participant. Belonging to an IBS group or control group did not have a significant effect on scores regarding affective temperaments, according to covariance analysis. Conclusion: There is relationship between affective temperaments and IBS. Lower education level, being unemployed and elder age is risky for higher scores of affective temperaments. A larger sample size may be helpful to define the detailed relationship between affective temperaments and IBS.

Association between the location of diverticular disease and the irritable bowel syndrome: a multicenter study in Japan.

OBJECTIVES:No previous reports have shown an association between location of diverticular disease (DD) and the irritable bowel syndrome (IBS).METHODS:We included 1,009 consecutive patients undergoing total colonoscopy in seven centers in Japan from June 2013 to September 2013. IBS was diagnosed using Rome III criteria, and diverticulosis was diagnosed by colonoscopy with transparent soft-short-hood. Left-sided colon was defined as sigmoid colon, descending colon, and rectum. Right-sided colon was defined as cecum, ascending colon, and transverse colon. We divided the patients into IBS and non-IBS groups and compared characteristics.RESULTS:Patient characteristics included mean age, 64.2±12.9 years and male:female ratio, 1.62:1. Right-sided DD was identified in 21.6% of subjects. Left-sided and bilateral DD was identified in 6.6 and 12.0% of subjects, respectively. IBS was observed in 7.5% of subjects. Multiple logistic regression analysis showed left-sided DD (odds ratio, 3.1; 95% confidence interval (CI): 1.4–7.1; P=0.0060) and bilateral DD (odds ratio, 2.6; 95% CI, 1.3–5.2; P=0.0070) were independent risk factors for IBS. Right-sided DD was not a risk factor for IBS.CONCLUSIONS:Our data showed that the presence of left-sided and bilateral DD, but not right-sided disease, was associated with a higher risk of IBS, indicating that differences in pathological factors caused by the location of the DD are important in the development of IBS. Clarifying the specific changes associated with left-sided DD could provide a better understanding of the pathogenic mechanisms of IBS (Trial registration # R000012739).

Fecal Calprotectin Levels for the Ethiological Diagnosis in Brazilian Patients With Gastrointestinal Symptoms

Introduction: Determination of fecal calprotectin (FC) can provide an important guidance for the physician, also in primary care, in the differential diagnosis of gastrointestinal disorders mainly between inflammatory bowel diseases (IBD) and irritable bowel syndrome (IBS). The aims of the present study were to prospectively investigate, in Brazilian adults with gastrointestinal complaints, the value of FC as a biomarker for the differential diagnosis between functional and organic disorders and to correlate the concentrations with the activity of IBD. Methods: The study included consecutive patients who had gastrointestinal complaints in which the measurement levels of FC were recommended. FC were measured using a Bühlmann (Basel, Switzerland) ELISA kit. Results: A total of 270 patients were included in the study, with median age of 39 years (range, 18-78 years). After clinical and laboratorial evaluation and considering the final diagnosis, patients were allocated into the following groups: a) IBS group: 154 patients (102 female and 52 male subjects), b) IBD group: 112 patients; 73 with Crohn’s disease (CD); 38 female and 35 male patients; 52.1% (38/73) presented active disease, and 47.9% (35/73) had disease in remission and 39 patients with ulcerative colitis (UC);19 female and 20 male patients; 48.7% (19/39) classified with active disease and 49.3% (20/39) with disease in remission. A significant difference (p<0.001) was observed between the median value of FC in IBS group that was 50.5 μg/g (IQR=16-294 μg/g); 405 μg/g (IQR=29-1980 μg/g) in CD patients and 457 μg/g (IQR=25-1430 μg/g) in UC patients. No difference was observed between the values found in the patients with CD and UC. Levels of FC were significantly lower in patients with IBD in remission when compared with active disease (p<0.001). Conclusion: The present study showed that the determination of FC assists to differentiate between active and inactive IBD and between IBD and IBS. Additionally, it may be used as a guide to classify the activity of the disease, monitor the treatment, predict relapses, and suggest if the clinical symptoms are from the basic disease or from functional comorbidity.Figure 1: Fecal calprotectin in the studied groups.

The effect of irritable bowel syndrome on carotid intima-media thickness, pulse wave velocity, and heart rate variability.

Irritable bowel syndrome (IBS), a subgroup of functional somatic disorders, may be associated with autonomic dysfunction (AD). Heart rate variability (HRV), a measure of autonomic dysfunction, may predict survival. The aim of this study was to investigate the effect of IBS on HRV parameters, carotid intima-media thickness (CIMT) and carotid-femoral pulse wave velocity (cf-PWV) as surrogates of AD, subclinical atherosclerosis and arterial stiffness, respectively. Our study was cross-sectional and observational. Thirty consecutive patients with IBS and 30 control participants underwent 24-hour Holter monitoring, cf-PWV assessment and CIMT measurement. The diagnosis of IBS was based on Rome III criteria. There were 24 patients with IBS-Constipation (80%), 4 patients with IBS-Diarrhea (13.3%), and 2 patients with IBS-Mixed (6.7%) in IBS group. Student t-test and χ2 test were utilized in order to compare continuous and categorical variables between two groups, respectively. Biochemical parameters did not differ between groups except for slightly increased creatinine in patients with IBS. cf-PWV and CIMT values were similar between groups. SDNN index and RMSSD were significantly impaired in patients with IBS compared to controls. Frequency analyses revealed lower LF, HF, and VLF in subjects with IBS. We demonstrated decreased parasympathetic modulation in patients with constipation predominant IBS. However, we could not demonstrate any changes in vascular structure and functions measured by carotid intima-media thickness and pulse wave velocity. Our results do not support accelerated atherosclerosis in IBS population.

Association of cannabinoid type 1 receptor and fatty acid amide hydrolase genetic polymorphisms in Chinese patients with irritable bowel syndrome

The endocannabinoid system is involved in the pathophysiology of irritable bowel syndrome (IBS). Here, we investigated whether genetic variants of the cannabinoid type 1 receptor (CNR1) and fatty acid amide hydrolase (FAAH) are associated with the pathogenesis of IBS. In total, 292 patients with IBS and 298 healthy controls were enrolled. Polymerase chain reaction (PCR) and DNA sequencing were applied to determine the genotyping of polymorphic triplet AAT repeats located at the 3'-end of the CNR1 gene. The single nucleotide polymorphism (SNP) C385A at the FAAH gene (rs324420) was determined by PCR using TaqMan SNP Genotyping Assay Sets. A total of eight alleles with AAT triplet repeats in the CNR1 gene were detected. The alleles were divided into two groups (≤ 10 and > 10) and three genotypes (≤ 10/≤ 10, ≤ 10/> 10, and > 10/> 10). The frequency of > 10 alleles was significantly higher in the IBS group (90.6%) when compared with the control group {81.7%, P < 0.001, odds ratio (OR) (95% confidence interval [CI]) = -0.128}. In addition, the genotypes > 10/> 10 were significantly associated with IBS (P < 0.001, OR [95% CI] = -0.163). The frequency of the A allele and the distribution of the AA genotype in the FAAH gene in the IBS group were not significantly different from those in the control group (P > 0.05), even though the frequency of the AA genotype was lower in the IBS group (1.0%) than that in the control group (3.4%, P = 0.089, OR [95% CI] = 3.345). The variation in the (AAT)n repeat of the CNR1 gene conferred an increased risk for developing IBS, while rs324420 (C385) in the FAAH gene was not associated with IBS pathogenesis.

Irritable bowel syndrome and symptom severity: Evidence of negative attention bias, diminished vigour, and autonomic dysregulation

ObjectiveTo determine if cognitive processing, and subjective and physiological responses to stress and relaxation differed between an irritable bowel syndrome (IBS) group and control group. How these variables relate to the severity of IBS symptoms was also determined. MethodsTwenty-one IBS participants and 20 controls provided cognitive (attention and processing), subjective (perceived stress and vigour), and physiological (heart rate, blood pressure, and skin conductance) data during a relaxation and stress phase. Logistic regression analyses determined which variables are related to the IBS group and hierarchical linear regression assessed how the variables are related to the severity of IBS symptoms. ResultsSubjective and cognitive factors (drowsiness at baseline, total vigour, and reduced Stroop colour-naming accuracy for negative words) are significantly related to IBS, χ2 (3, N=41)=23.67, p<.001, accurately categorising 85% of participants. IBS symptom severity was associated with both subjective (drowsiness at baseline and a smaller reduction in tiredness from relaxation to stress) and physiological (smaller increase in systolic blood pressure from baseline to stress phase and lower skin conductance at baseline) variables. This model predicted IBS severity, F (4, 16)=11.20, p<.001, and accounted for 74% of the variability in scores. ConclusionsA negative attention bias, which may be related to a negative self-schema, as well as perceived low vigour were important in categorising IBS. Low subjective vigour and reduced physiological reactivity to both relaxation and stress conditions were associated with IBS severity, suggestive of illness-related allostatic load.

Development of determination of four analytes of Zhi‐Shao‐San decoction using LC‐MS/MS and its application to comparative pharmacokinetics in normal and irritable bowel syndrome rat plasma

Zhi-Shao-San (ZSS), a traditional Chinese medicinal prescription, has been clinically used for the treatment of irritable bowel syndrome (IBS) for centuries. A comparative study was designed and conducted to compare the pharmacokinetic differences between paeoniflorin naringin, hesperidin and neohesperidin after oral administration of ZSS decoction to normal rats and IBS rats induced by acetic acid and restraint stress. Further, an efficient, sensitive and selective liquid chromatography/tandem mass spectrometry for the simultaneous determination of four analytes of ZSS decoction in rat plasma was developed and validated. The validated method was successfully applied to comparison of pharmacokinetic profiles of analytes in rat plasma. The results showed that the absorptions of naringin, hesperidin and neohesperidin in IBS group were all significantly higher than those in normal group and no obvious difference was seen for paeoniflorin between the two groups, which is helpful for improving clinical therapeutic efficacy and further pharmacological studies of ZSS.

Conditioned Pain Modulation in Women With Irritable Bowel Syndrome

Evidence suggests that patients with irritable bowel syndrome (IBS) are more vigilant to pain-associated stimuli. The aims of this study were to compare women with IBS (n = 20) to healthy control (HC, n = 20) women on pain sensitivity, conditioned pain modulation (CPM) efficiency, and salivary cortisol levels before and after the CPM test and to examine the relationship of CPM efficiency with gastrointestinal pain, somatic pain, psychological distress symptoms, and salivary cortisol levels in each group. Women, aged 20-42 years, gave consent, completed questionnaires, and kept a symptom diary for 2 weeks. CPM efficiency was tested with a heat test stimulus and cold water condition stimulus in a laboratory between 8 and 10 a.m. on a follicular phase day. Salivary cortisol samples were collected just before and after the experimental testing. Compared to the HC group, women with IBS reported more days with gastrointestinal and somatic pain/discomfort, psychological distress, fatigue, and feeling stressed. During the CPM baseline testing, women with IBS reported greater pain sensitivity compared to the HC group. There was no significant group difference in salivary cortisol levels nor in CPM efficiency, though a post-hoc analysis showed a higher prevalence of impaired CPM efficiency among IBS subjects with more severe lower-GI symptoms. In the IBS group, reduced CPM efficiency was associated with daily abdominal pain/discomfort and psychological distress. Overall, women with IBS exhibited an increased sensitivity to thermal stimuli. Impaired CPM was present in a subset of women with IBS.