Testing a biobehavioral model of irritable bowel syndrome

Association between Dietary Habits and Fecal Microbiota Composition in Irritable Bowel Syndrome Patients: A Pilot Study

Intestinal dysbiosis seems to play a role in the pathophysiology of irritable bowel syndrome (IBS). The present pilot study aimed to elucidate the association between nutrient intake and Mediterranean diet (MD) adherence with IBS symptoms and gut microbiota in IBS patients. The nutrient intake of 28 IBS patients and 21 controls was assessed through a food diary, the reference intake ranges (RIs) for energy-yielding macronutrients and the MD serving score (MDSS) index. MD adherence and nutrients intake were compared to IBS symptoms and fecal microbiota, obtained by 16S rRNA targeted-metagenomics. In IBS patients MDSS index was altered compared to controls (p < 0.01). IBS patients with low-MD score reported severe abdominal pain and higher flatulence point-scales. Through Linear discriminant analysis effect size (LEfSe), Erysipelotrichaceae were detected as a microbial biomarker in IBS patients with altered RIs for macronutrients intake, compared to controls. Lactobacillaceae and Lactobacillus were associated to an altered carbohydrates intake in IBS patients, while specific taxonomic biomarkers, such as Aldercreuzia, Mogibacteriaceae, Rikenellaceae, Parabacteroides and F. prausnitzii were associated with an adequate intake of nutrient in these patients. This study supports an association between dietary patterns and gut microbial biomarkers in IBS patients. Further investigations are needed to clarify these connections.

Cognitive behavioral therapy for irritable bowel syndrome: the effects on state and trait anxiety and the autonomic nervous system during induced rectal distensions - An uncontrolled trial

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS), is a common multifactorial gastrointestinal disorder linked to disturbances in the microbe gut-brain axis. Cognitive behavioral therapy (CBT), in face-to-face format has showed promising results on IBS and its associated psychological symptoms. The present study explored for the first time if CBT for IBS affects the autonomic nervous system (ANS) during experimentally induced visceral pain and cognitive stress, respectively. The levels of state and trait anxiety, current and perceived stress were also evaluated.

METHODS

In this uncontrolled trial, individual CBT was performed in face-to-face format for 12 weeks in 18 subjects with IBS. Heart rate variability and skin conductance were measured during experimentally induced visceral pain and during a cognitive task (Stroop color-word test), before and after intervention. The levels of state and trait anxiety as well as self-rated current and perceived stress were also measured before and after the intervention.

RESULTS

CBT did not affect ANS activity during experimentally induced visceral pain and cognitive stress. The sympathetic activity was high, typical for IBS and triggered during both visceral pain and cognitive stress. The levels of state and trait anxiety significantly decreased after the intervention. No significant changes in self-rated current or perceived stress were found.

CONCLUSIONS

Results suggest that face-to-face CBT for IBS improved anxiety- a key psychological mechanism for the IBS pathophysiology, rather than the autonomic stress response to experimentally induced visceral pain and cognitive stress, respectively.

IMPLICATIONS

This study indicates that IBS patients present high levels of stress and difficulties coping with anxiety and ANS activity during visceral pain and a cognitive stress test, respectively. These manifestations of IBS are however not targeted by CBT, and do not seem to be central for the study participants IBS symptoms according to the current and our previous study. Face-to-face CBT for IBS, it does not seem to affect modulation of ANS activity in response to induced visceral pain or cognitive stress. Instead, face-to-face CBT decreased levels of state and trait anxiety. Implications for further studies include that anxiety seems to be important in the IBS pathophysiology, and needs further scientific attention. This is in line with the fear-avoidance model which suggests that anxious responses to pain and discomfort drive hypervigilance to, and (behavioral) avoidance of, symptom provoking stimuli and vice versa. Catastrophic cognitions, hypervigilance and avoidant behavioral responses are proposed to produce vicious circles that withhold and exacerbate pain-related symptoms and disability, and lead to lower quality of life. Larger scale studies of potential autonomic changes are needed in order to elucidate which mechanisms elicit its effects in face-to-face CBT for IBS, and provide new avenues in understanding the pathophysiology of IBS.

Irritable bowel syndrome - from etiopathogenesis to therapy

Irritable bowel syndrome (IBS) is a chronic and relapsing functional gastrointestinal disorder that affects 9-23% of the population across the world. Patients with IBS are often referred to gastroenterology, undergo various investigations, take various medicines, take time off work and have a poor quality of life. The pathophysiology of IBS is not yet completely understood and seems to be multifactorial. Many pathogenetic factors, in various combinations, and not all necessarily present in each patient, can play an important role. Discomfort or abdominal pain relieived by defacation, asociated with a change in stool form, is a typical clinical manifestation of IBS. Many factors, such as emotional stress and eating, may exacerbate the symptoms. A timely diagnosis of IBS is important so that treatment which will provide adequate symptomatic relief (diarrhoea, constipation, pain and boaring) can be introduced. The diagnosis of IBS is not confirmed by a specific test or structural abnormality. It is made using criteria based on clinical symptoms such as Rome criteria, unless the symptoms are thought to be atypical. Today the Rome Criteria IV is the current gold-standard for the diagnoses of IBS. Treatment of patients with IBS requires a multidisciplinary approach. Some patients respond well to non-pharmacological treatment, while others also require pharmacological treatment. This review will provide a summary of pathophysiology, diagnostic criteria and therapies for IBS.

Face-to-Face Cognitive-Behavioral Therapy for Irritable Bowel Syndrome: The Effects on Gastrointestinal and Psychiatric Symptoms

Irritable bowel syndrome (IBS) is a gastrointestinal disorder linked to disturbances in the gut-brain axis. Visceral hypersensitivity and pain are hallmarks of IBS and linked to the physiological and psychological burden and to the nonadaptive coping with stress. Cognitive-behavioral therapy (CBT) for IBS has proven effective in reducing gastrointestinal and psychiatric symptoms in IBS by means of coping with stress. The present pilot study evaluated for the first time whether CBT for IBS affected visceral sensitivity and pain. Individual CBT was performed for 12 weeks in 18 subjects with IBS and evaluated in terms of visceral sensitivity and pain during rectal distensions using the barostat method and self-rated visceral sensitivity and gastrointestinal and psychiatric symptoms. Visceral discomfort, urge, and pain induced by the barostat were not affected by CBT but were stable across the study. However, the level of self-rated visceral sensitivity and gastrointestinal and psychiatric symptoms decreased after the intervention. Central working mechanisms and increased ability to cope with IBS-symptoms are suggested to play a key role in the alleviation of IBS symptoms produced by CBT.

Fecal Calprotectin and serum chromogranin A as potential biomarkers of irritable bowel syndrome symptom severity

Irritable bowel syndrome (IBS) is a disorder of the lower gastrointestinal (GI) tract, which manifests as abdominal pain and/or discomfort accompanied by altered bowel function, in the absence of structural pathology. The onset and precipitation of IBS is the result of an interaction among several factors, including psychological distress, altered GI sensation and processing of sensory information as well as GI inflammation. These factors have varying contributions to disorder etiology in different patients, and in line with that, there is now emerging evidence about a low-grade inflammation in a subgroup of IBS patients. Because IBS diagnosis is based on the ROME III criteria, with the exclusion of structural pathology, patients are often exposed to numerous invasive and unpleasant tests. In order to decrease the cost of repeated testing, while simultaneously alleviating patients' anxiety, research should be aimed at detecting cost-effective biomarkers. We hypothesize chromogranin A (CgA) and fecal Calprotectin (FC) could be used to eliminate possible organic causes of IBS symptoms. Also, we hypothesize FC could be helpful in detecting IBS patients with low-grade inflammation. Forty-eight outpatients with IBS (76% females) completed a set of psychosocial measures (HRQoL, STAI, BDI, VSI, SF-36), and their FC and CgA levels were obtained. We found elevated CgA levels in 4 patients, but CgA levels were not related to any of the psychological measures used. Elevated FC levels were found in 12 patients. FC levels significantly correlated with the physical component of health related quality of life (HRQoL) (r48=-.42, p<.01). In addition, one-way ANOVA's were performed to test possible differences in psychosocial measures depending on the patient's FC status. The analysis showed only one significant difference. Patients with the highest levels of FC had significantly lower physical component of HRQoL compared to the other two groups of patients.

Cognitive behavioral approach to understanding irritable bowel syndrome

Irritable bowel syndrome (IBS) is considered a biopsychosocial disorder, whose onset and precipitation are a consequence of interaction among multiple factors which include motility disturbances, abnormalities of gastrointestinal sensation, gut inflammation and infection, altered processing of afferent sensory information, psychological distress, and affective disturbances. Several models have been proposed in order to describe and explain IBS, each of them focusing on specific aspects or mechanisms of the disorder. This review attempts to present and discuss different determinants of IBS and its symptoms, from a cognitive behavioral therapy framework, distinguishing between the developmental predispositions and precipitants of the disorder, and its perpetuating cognitive, behavioral, affective and physiological factors. The main focus in understanding IBS will be placed on the numerous psychosocial factors, such as personality traits, early experiences, affective disturbances, altered attention and cognitions, avoidance behavior, stress, coping and social support. In conclusion, a symptom perpetuation model is proposed.