Impaired drinking capacity in patients with functional dyspepsia: relationship with proximal stomach function

The effect of 10-week long yoga training on interoceptive abilities: cross-sectional and longitudinal investigation of cardiac and gastric accuracy

Based on their characteristics, it is likely that mind-body techniques develop interoception, the perception of bodily state. Nevertheless, findings on mindfulness, meditation, yoga, and body scan techniques are inconclusive. Additionally, the methodological scope is not exhaustive, neither in terms of the intervention nor the applied measure of interoception. This study investigated for the first time the effect of regular yoga training on cardiac and gastric perceptual ability (measured with the mental heartbeat tracking task and the water load task, respectively). With the involvement of 90 female university students (yoga group n = 57, control group n = 33) we did not find any connection between baseline heartbeat perception score and gastric fullness. Moreover, the applied 10-week-long regular yoga training did not develop any of the measured interoceptive abilities. We conclude that yoga might develop other abilities than these specific sensations. Very probably, the measured cardiac and gastric perceptual abilities do not represent bodily sensations in general. It would be worth to investigate, however, the effect of longer yoga training on interoception.

Nutrition and Disorders of Gut-Brain Interaction

BACKGROUND

Disorders of gut-brain interaction (DGBIs) have a complex pathophysiology that is often characterized by a relationship between food ingestion and triggering of symptoms. Understanding of the underlying mechanisms and the role of nutrients as a therapeutic target are rapidly evolving.

AIMS AND METHODS

We performed a narrative review of the literature using the following keywords, their acronyms, and their associations: nutrients, disorders of gut-brain interaction; functional dyspepsia; malabsorption; irritable bowel syndrome; diarrhea; constipation.

RESULTS

Functional dyspepsia displayed a significant correlation between volume, fat and/or wheat abundance, chemical composition of ingested food and symptoms of early satiety, fullness and weight loss. Carbohydrate malabsorption is related to enzyme deficiency throughout the GI tract. Food composition and richness in soluble vs. non-soluble fibers is related to constipation and diarrhea. The elimination of fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) has a significant and non-unidirectional impact on irritable bowel syndrome (IBS) symptoms.

CONCLUSIONS

Food volume, nutritive and chemical composition, and its malabsorption are associated with symptom generation in DGBIs. Further multicenter, randomized-controlled clinical trials are needed to clarify the underlying pathophysiology.

Review article: Functional dyspepsia-a gastric disorder, a duodenal disorder or a combination of both?

BACKGROUND

Functional dyspepsia (FD) is one of the most frequent conditions in gastroenterological outpatient health care. Most recent research in FD has shifted its focus to duodenal pathophysiological mechanisms, although current treatments still focus mainly the stomach.

AIM

The aim of the study was to provide a comprehensive overview of the pathophysiology of FD focusing on a paradigm shift from gastric towards duodenal mechanisms.

METHODS

We conducted a literature search in PubMed for studies describing mechanisms that could possibly cause FD.

RESULTS

The pathophysiology of FD remains incompletely understood. Recent studies show that duodenal factors such as acid, bile salt exposure and eosinophil and mast cell activation correlate with symptom pattern and burden and can be associated with gastric sensorimotor dysfunction. The evolving data identify the duodenum an interesting target for new therapeutic approaches. Furthermore, the current first-line treatment, that is proton pump inhibitors, reduces duodenal low-grade inflammation and FD symptoms.

CONCLUSION

Future research for the treatment of FD should focus on the inhibition of duodenal mast cell activation, eosinophilia and loss of mucosal integrity.

Understanding neuroimmune interactions in disorders of gut-brain interaction: from functional to immune-mediated disorders

Functional gastrointestinal disorders-recently renamed into disorders of gut-brain interaction-such as irritable bowel syndrome and functional dyspepsia are highly prevalent conditions with bothersome abdominal symptoms in the absence of structural abnormalities. While traditionally considered as motility disorders or even psychosomatic conditions, our understanding of the pathophysiology has evolved significantly over the last two decades. Initial observations of subtle mucosal infiltration with immune cells, especially mast cells and eosinophils, are since recently being backed up by mechanistic evidence demonstrating increased release of nociceptive mediators by immune cells and the intestinal epithelium. These mediators can activate sensitised neurons leading to visceral hypersensitivity with bothersome symptoms. The interaction between immune activation and an impaired barrier function of the gut is most likely a bidirectional one with alterations in the microbiota, psychological stress and food components as upstream players in the pathophysiology. Only few immune-targeting treatments are currently available, but an improved understanding through a multidisciplinary scientific approach will hopefully identify novel, more precise treatment targets with ultimately better outcomes.

Effect of intracolonic volume on gastric sensory-motor responses in constipation-predominant irritable bowel syndrome

BACKGROUND

Interaction between gut stimuli may induce symptom overlap in patients with functional gastrointestinal disorders. The aim is to determine the effect of increased volumes of colonic contents on gastric sensory/motor responses and satiety in patients with constipation-predominant irritable bowel syndrome (IBS-C) and overlapping dyspeptic symptoms, and a cohort of healthy subjects.

METHODS

In 15 patients with IBS-C and 10 healthy subjects, the effect of real versus sham colonic filling with gas (1080 ml) on gastric sensitivity (measured by stepwise distensions of the stomach), gastric compliance, abdominal perception, and nutrient drink tolerance was studied on separate days.

RESULTS

In healthy subjects, colonic gas filling induced an increment in gastric sensitivity to distension (mean score 2.0 ± 0.2 before, and 3.0 ± 0.4 after; p = 0.038). In IBS, basal sensitivity was greater and remained unchanged after colonic gas filling (score 4.0 ± 0.1 and 3.8 ± 0.3, respectively; p < 0.001 vs. basal in health). Colonic gas infusion induced abdominal symptoms that were significantly greater in IBS-C (score 2.6 ± 0.1) than in health (score 1.7 ± 0.4; p = 0.027), with minor changes in gastric tone, and no changes in gastric compliance in both groups. Colonic filling produced a profound reduction in nutrient drink tolerance in IBS (791 ± 87 ml sham filling, 491 ± 58 ml gas filling; p < 0.001) but only a minor reduction in health (940 ± 70 ml sham filling, 860 ± 94 ml gas filling; p = 0.223).

CONCLUSIONS & INFERENCES

The volume of the colonic contents modulates satiety in patients with IBS-C, due to a general visceral pan-hypersensitivity. These effects should be considered in the choice of treatment for constipation in these patients.

Standardized system and App for continuous patient symptom logging in gastroduodenal disorders: Design, implementation, and validation

BACKGROUND

Functional gastroduodenal disorders include functional dyspepsia, chronic nausea and vomiting syndromes, and gastroparesis. These disorders are common, but their overlapping symptomatology poses challenges to diagnosis, research, and therapy. This study aimed to introduce and validate a standardized patient symptom-logging system and App to aid in the accurate reporting of gastroduodenal symptoms for clinical and research applications.

METHODS

The system was implemented in an iOS App including pictographic symptom illustrations, and two validation studies were conducted. To assess convergent and concurrent validity, a diverse cohort with chronic gastroduodenal symptoms undertook App-based symptom logging for 4 h after a test meal. Individual and total post-prandial symptom scores were averaged and correlated against two previously validated instruments: PAGI-SYM (for convergent validity) and PAGI-QOL (for concurrent validity). To assess face and content validity, semi-structured qualitative interviews were conducted with patients.

KEY RESULTS

App-based symptom reporting demonstrated robust convergent validity with PAGI-SYM measures of nausea (r_S  =0.68), early satiation (r_S  =0.55), bloating (r_S  =0.48), heartburn (r_S  =0.47), upper gut pain (r_S  =0.40), and excessive fullness (r_S  =0.40); all p < 0.001 (n = 79). The total App-reported Gastric Symptom Burden Score correlated positively with PAGI-SYM (r_S  =0.56; convergent validity; p < 0.001), and negatively with PAGI-QOL (r_S  = -0.34; concurrent validity; p = 0.002). Interviews demonstrated that the pictograms had adequate face and content validity.

CONCLUSIONS AND INFERENCES

The continuous patient symptom-logging App demonstrated robust convergent, concurrent, face, and content validity when used within a 4-h post-prandial test protocol. The App will enable standardized symptom reporting and is anticipated to provide utility in both research and clinical practice.

Gastric accommodation: Physiology, diagnostic modalities, clinical relevance, and therapies

BACKGROUND

Gastric accommodation is an essential gastric motor function which occurs following ingestion of a meal. Impaired gastric fundic accommodation (IFA) is associated with dyspeptic symptoms. Gastric accommodation is mediated by the vagal pathway with several important physiologic factors such as duodenal nutrient feedback playing a significant role. IFA has been described as a pathophysiologic factor in several gastrointestinal disorders including functional dyspepsia, diabetic gastropathy, post-Nissen fundoplication, postsurgical gastrectomy, and rumination syndrome. Modalities for gastric accommodation assessment include gastric barostat, intragastric meal distribution via scintigraphy, drinking tests (eg, water load), SPECT, MRI, 2D and 3D ultrasound, and intragastric high-resolution manometry. Several treatment options including sumatriptan, buspirone, tandospirone, ondansetron, and acotiamide may improve symptoms by increasing post-meal gastric volume.

PURPOSE

Our aim is to provide an overview of the physiology, diagnostic modalities, and therapies for IFA. A literature search was conducted on PubMed, Google Scholar, and other sources to identify relevant studies available until December 2020. Gastric accommodation is an important gastric motor function which if impaired, is associated with several upper gastrointestinal disorders. There are an increasing number of gastric accommodation testing modalities; however, each has facets which warrant consideration. Evidence regarding potentially effective therapies for IFA is growing.

Diagnostic Evaluation of Gastric Motor and Sensory Disorders

Disorders of gastric motor and sensory function affect 10%-20% of the world's population and adversely impact nutrition, quality of life, work productivity, and health care costs. Classifying these disorders can be challenging given the heterogeneity of symptom presentation, the presence of symptoms unexplained by endoscopic, radiographic and/or laboratory evaluation, and overlap with other luminal gastrointestinal disorders. Accurately diagnosing these highly prevalent disorders relies upon an understanding of epidemiology and risk factors, the ability to take a careful clinical history focused on symptoms, and the presence of predisposing medical, surgical, and psychological conditions. A variety of diagnostic studies are now available to assess gastric motor function and identify maladaptive relaxation, accommodation, and abnormal sensation. FDA-approved treatment options are limited and thus many patients undergo a series of empirical treatment trials that target individual symptoms, often without much benefit. This article provides updated recommendations for identifying and classifying the most common gastric motor and sensory disorders using currently accepted diagnostic tests, and provides a brief supplemental overview on treatment options. "Things sweet to taste prove in digestion sour." -Shakespeare, Richard II, 1595.

A Preclinical Feasibility Study of Endoscopic Barostat: A Possible Diagnostic Tool for Visceral Hypersensitivity in Functional Dyspepsia

INTRODUCTION

Diagnosing functional dyspepsia requires excluding organic disease and gastrointestinal function evaluation; however, there are no modalities to evaluate these simultaneously. This preclinical study examined the possibility of an endoscopic barostat.

METHODS

Ultrathin endoscopy and our newly developed pressure-regulated endoscopic insufflator, which insufflates the gastrointestinal tract until the preset pressure is achieved, were used. The actual intragastric pressure was measured using an optical fiber manometer placed in the stomach. Experiment-1: in an ex vivo experiment, we insufflated the isolated stomach and verified whether the intragastric pressure reached the preset pressure. Experiment-2: we inserted the endoscope orally in a porcine stomach, insufflated the stomach, and verified whether the intragastric pressure reached the preset pressure. Finally, we insufflated the stomach at a random pressure to verify the functional tests for proof-of-concept.

RESULTS

Experiment-1: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.015, regression line: 0.988, 95% confidence interval [CI]: 0.994-0.994). Experiment-2: the intragastric pressure reached the preset pressure. After reaching the plateau, the pressure remained stable at the preset pressure (Huber M value: 1.018, regression line: 0.971, 95% CI: 0.985-0.986). At randomly preset pressures, the transendoscopic theoretical intragastric pressure detected by using the insufflator was correlated with the actual pressure measured by using the pressure manometer.

CONCLUSIONS

This proof-of-concept study shows that a pressure-regulated endoscopic insufflator provides stable intragastric pressure at the preset level, with the potential of an endoscopic barostat to assess the visceral hypersensitivity related to functional dyspepsia.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on functional dyspepsia

BACKGROUND

Functional dyspepsia (FD) is one of the most common conditions in clinical practice. In spite of its prevalence, FD is associated with major uncertainties in terms of its definition, underlying pathophysiology, diagnosis, treatment, and prognosis.

METHODS

A Delphi consensus was initiated with 41 experts from 22 European countries who conducted a literature summary and voting process on 87 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 36 statements.

RESULTS

The panel agreed with the definition in terms of its cardinal symptoms (early satiation, postprandial fullness, epigastric pain, and epigastric burning), its subdivision into epigastric pain syndrome and postprandial distress syndrome, and the presence of accessory symptoms (upper abdominal bloating, nausea, belching), and overlapping conditions. Also, well accepted are the female predominance of FD, its impact on quality of life and health costs, and acute gastrointestinal infections, and anxiety as risk factors. In terms of pathophysiological mechanisms, the consensus supports a role for impaired gastric accommodation, delayed gastric emptying, hypersensitivity to gastric distention, Helicobacter pylori infection, and altered central processing of signals from the gastroduodenal region. There is consensus that endoscopy is mandatory for establishing a firm diagnosis of FD, but that in primary care, patients without alarm symptoms or risk factors can be managed without endoscopy. There is consensus that H. pylori status should be determined in every patient with dyspeptic symptoms and H. pylori positive patients should receive eradication therapy. Also, proton pump inhibitor therapy is considered an effective therapy for FD, but no other treatment approach reached a consensus. The long-term prognosis and life expectancy are favorable.

CONCLUSIONS AND INFERENCES

A multinational group of European experts summarized the current state of consensus on the definition, diagnosis and management of FD.

Non-uniform gastric wall kinematics revealed by 4D Cine magnetic resonance imaging in humans

BACKGROUND

Assessment of gastric function in humans has relied on modalities with varying degrees of invasiveness, which are usually limited to the evaluation of single aspects of gastric function, thus requiring patients to undergo a number of often invasive tests for a full clinical understanding. Therefore, the development of a non-invasive tool able to concurrently assess multiple aspects of gastric function is highly desirable for both research and clinical assessments of gastrointestinal (GI) function. Recently, technological advances in magnetic resonance imaging (MRI) have provided new tools for dynamic (or "cine") body imaging. Such approaches can be extended to GI applications.

METHODS

In the present work, we propose a non-invasive assessment of gastric function using a four-dimensional (4D, volumetric cine imaging), free-breathing MRI sequence with gadolinium-free contrast enhancement achieved through a food-based meal. In healthy subjects, we successfully estimated multiple parameters describing gastric emptying, motility, and peristalsis propagation patterns.

KEY RESULTS

Our data demonstrated non-uniform kinematics of the gastric wall during peristaltic contraction, highlighting the importance of using volumetric data to derive motility measures.

CONCLUSIONS & INFERENCES

MRI has the potential of becoming an important clinical and gastric physiology research tool, providing objective parameters for the evaluation of impaired gastric function.

Nutrient Drinking Test as Biomarker in Functional Dyspepsia

INTRODUCTION

Functional dyspepsia (FD) is a prevalent condition with multifactorial pathophysiology, including impaired gastric accommodation (GA), hypersensitivity to gastric distention, and delayed gastric emptying. Drink tests (DT) have been proposed as a potential biomarker for the presence and severity of gastric sensorimotor dysfunction. Thus, we aimed to summarize the state of knowledge on different DT and their potential as a biomarker for FD.

METHODS

A PubMed and MEDLINE search was conducted for English language articles, reviews, meta-analyses, case series, and randomized controlled trials, including also published meeting abstracts.

RESULTS

Several DT have been described in literature (e.g., different type of liquid, number of calories used, pace of drinking, and subject's awareness of the amount of liquid drunk). FD patients ingest significantly less volume in the different variants of the tests. The slow nutrient ("satiety drinking") test (SDT) studies show the most consistent separation between health and FD and correlation with GA. However, sensitivity to distention may be correlated with rapid DT. SDTs were used to evaluate the effect of several pharmacological agents, often showing concordance between their effects on GA and tolerated nutrient volume. This correlation was not found mainly for agents with central actions.

DISCUSSION

An SDT is a potential diagnostic biomarker in FD, reflecting GA. Additional studies are required to confirm its role as a predictive biomarker for treatment outcome in FD.

Gastric interoception and gastric myoelectrical activity in bulimia nervosa and binge-eating disorder

OBJECTIVE

Identifying factors that control food intake is crucial to the understanding and treatment of eating disorders characterized by binge eating. In healthy individuals, stomach distension plays an important role in the development of satiation, but gastric sensations might be overridden in binge eating. The present study investigated the perception of gastric signals (i.e., gastric interoception) and gastric motility in patients experiencing binge-eating episodes, that is, bulimia nervosa (BN) and binge-eating disorder (BED).

METHOD

Twenty-nine patients with BN or BED (ED group) and 32 age-, sex-, and BMI-matched healthy controls (HC group) participated in the study. The onset of satiation and stomach fullness were assessed using a novel 2-step water load test (WLT-II). Gastric myoelectrical activity (GMA) was measured by electrogastrography (EGG) before and after ingestion of noncaloric water.

RESULTS

Individuals in the ED group drank significantly more water until reporting satiation during the WLT-II. The percentage of normal gastric myoelectrical power was significantly smaller in the ED group compared to HC, and negatively related to the number of objective binge-eating episodes per week in patients with BN or BED. Power in the bradygastria range was greater in ED than in HC participants.

DISCUSSION

Patients with EDs have a delayed response to satiation compared to HC participants, together with abnormal GMA. Repeated binge-eating episodes may induce disturbances to gastric motor function.

United European Gastroenterology (UEG) and European Society for Neurogastroenterology and Motility (ESNM) consensus on functional dyspepsia

Background

Functional dyspepsia (FD) is one of the most common conditions in clinical practice. In spite of its prevalence, FD is associated with major uncertainties in terms of its definition, underlying pathophysiology, diagnosis, treatment, and prognosis.

Methods

A Delphi consensus was initiated with 41 experts from 22 European countries who conducted a literature summary and voting process on 87 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus (defined as >80% agreement) was reached for 36 statements.

Results

The panel agreed with the definition in terms of its cardinal symptoms (early satiation, postprandial fullness, epigastric pain, and epigastric burning), its subdivision into epigastric pain syndrome and postprandial distress syndrome, and the presence of accessory symptoms (upper abdominal bloating, nausea, belching), and overlapping conditions. Also, well accepted are the female predominance of FD, its impact on quality of life and health costs, and acute gastrointestinal infections, and anxiety as risk factors. In terms of pathophysiological mechanisms, the consensus supports a role for impaired gastric accommodation, delayed gastric emptying, hypersensitivity to gastric distention, Helicobacter pylori infection, and altered central processing of signals from the gastroduodenal region. There is consensus that endoscopy is mandatory for establishing a firm diagnosis of FD, but that in primary care, patients without alarm symptoms or risk factors can be managed without endoscopy. There is consensus that H. pylori status should be determined in every patient with dyspeptic symptoms and H. pylori positive patients should receive eradication therapy. Also, proton pump inhibitor therapy is considered an effective therapy for FD, but no other treatment approach reached a consensus. The long‐term prognosis and life expectancy are favorable.

Conclusions and Inferences

A multinational group of European experts summarized the current state of consensus on the definition, diagnosis and management of FD.

Current knowledge

Functional dyspepsia is one of the most common conditions encountered in clinical practice.

There is a lack of guidance for clinicians in guiding diagnosis and treatment of this prevalent condition.

No treatments are currently approved for the treatment of functional dyspepsia in Europe.

What is new here

A Delphi panel consisting of 41 experts from 22 European countries established the level of consensus on 87 statements regarding functional dyspepsia.

The statements reaching consensus serve to guide clinicians in recognizing, diagnosing and treating FD in clinical practice.

Endoscopy is mandatory for establishing a firm diagnosis of functional dyspepsia D, but in primary care patients without alarm symptoms or risk factors can be managed without endoscopy.

Helicobacter pylori status should be determined in every patient with dyspeptic symptoms and H. Pylori positive patients should receive eradication therapy.

Proton pump inhibitor‐therapy is considered an effective therapy for FD, but no other treatment approach reached consensus support.

The water load test in school children and adolescents with functional gastrointestinal disorders

BACKGROUND/AIMS

We hypothesize that patients with functional gastrointestinal disorders (FGID) drink less water volume than healthy subjects during water load test. We evaluated and compared the water load test in students with and without FGID using the Rome III questionnaire.

METHODS

We performed the water load test in 142 students from two schools in Colombia. Students were diagnosed using the Spanish version of the Rome III questionnaire. Students drank water ad libitum for 3 min or until pain, satiety, or vomiting occurred. We correlated anthropometric variables with water volumes drunk. We recorded symptoms like pain and nausea, before and after the water load test.

RESULTS

We evaluated 142 students, with a mean age of 12.1 ± 0.2 years and 59.9% girls. Mean water volume drunk was 459 ± 22 mL. There was no significant difference between water volume drunk by students with and without FGID (466 ± 36 vs. 453 ± 27 mL, p = 0.108). We found a significant correlation between water volume drunk and gender, age, weight, height, and body mass index.

CONCLUSIONS

Students with and without FGID ingest similar volumes of water. Test adverse effects are minimal, and the test is safe to perform and well tolerated.

Reference values for the water load test in healthy school children and adolescents

BACKGROUND AND STUDY AIM

The water load test (WLT) is an easy and cheap tool, useful in evaluating gastric accommodation and visceral hypersensitivity. This test can be used in diagnosing functional gastrointestinal disorders, like functional dyspepsia. Our main aim was to propose reference values for the WLT. Our secondary aim was to correlate the water volume drunk with the students' gender, age, and anthropometric measures.

PATIENTS AND METHODS

We performed the WLT in students aged 8 to 17 years. Students drank water ad libitum for 3 minutes or until pain, satiety or vomiting occurred. We correlated anthropometric variables with water volumes drunk. Upper and lower limit for the maximum tolerated volume were calculated as the 5th and 95th percentile. Pain and nausea were recorded before and after the test.

RESULTS

We evaluated 99 students, with a median age (inter quartile range) of 11 years 10-13 years) and 55.6 % were girls. Median water volume drank was 380 ml (190-540 ml). Boys (523 ml, interquartile range : 275-760 ml) drank more water than girls (380 ml, interquartile range : 190-570 ml) (p = 0.016). There was a significant correlation between water volume drank and students´ age, weight, height, and body mass index. Of the students that completed the WLT, 22.2 % had nausea and 30.3 % had mild abdominal pain after the test.

CONCLUSIONS

We proposed reference values for the WLT in children aged 8 to 17 years. Adverse effects are minimal, it is safe to perform, and well tolerated.

Functional Dyspepsia: A Narrative Review With a Focus on Sex-Gender Differences

Functional dyspepsia (FD) is among the most common gastrointestinal disorders affecting quality of life (QoL). As it frequently occurs in women than in men the comparison of various aspects including prevalence, clinical manifestations, and QoL in FD between women and men is very important for understanding the disease distribution and burden, evaluating treatment options, developing new drugs, and allocating medical resources. However, little is known about sex or gender differences among patients with FD. In spite of limited studies, consistent points are that FD occurs more often in women than in men and there are several symptom differences between men and women with FD. In addition, women with FD tend to have lower QoL than men with FD. Similarly, the pathophysiology of FD likely to vary depending on gender. Furthermore, a sex-gender-oriented approach in healthcare system could enhance understanding heterogeneous patients suffering from FD. Due to the sex-gender differences in physiological and psychological factors, treatment strategies should differ between women and men with FD. In conclusion, an individualized and multicomponent approach that considers sex and gender issues might improve FD treatment and improve patient Qol, especially for women.

Influence of Physical Activity Interventions on Body Representation: A Systematic Review

Distorted representation of one's own body is a diagnostic criterion and corepsychopathology of disorders such as anorexia nervosa and body dysmorphic disorder. Previousliterature has raised the possibility of utilising physical activity intervention (PI) as atreatment option for individuals suffering from poor body satisfaction, which is traditionallyregarded as a systematic distortion in "body image." In this systematic review,conducted according to the PRISMA statement, the evidence on effectiveness of PI on body representation outcomes is synthesised. We provide an update of 34 longitudinal studies evaluating the effectiveness of different types of PIs on body representation. No systematic risk of bias within or across studies were identified. The reviewed studies show that the implementation of structured PIs may be efficacious in increasing individuals' satisfaction of their own body, and thus improving their subjective body image related assessments. However, there is no clear evidence regarding an additional or interactive effect of PI when implemented in conjunction with established treatments for clinical populations. We argue for theoretically sound, mechanism-oriented, multimethod approaches to future investigations on body image disturbance. Specifically, we highlight the need to consider expanding the theoretical framework for the investigation of body representation disturbances to include further body representations besides body image.

Diet and functional dyspepsia: Clinical correlates and therapeutic perspectives

Hypervigilance and symptoms anticipation, visceral hypersensitivity and gastroduodenal sensorimotor abnormalities account for the varied clinical presentation of functional dyspepsia (FD) patients. Many patients recognize meals as the main triggering factor; thus, dietary manipulations often represent the first-line management strategy in this cohort of patients. Nonetheless, scarce quality evidence has been produced regarding the relationship between specific foods and/or macronutrients and the onset of FD symptoms, resulting in non-standardized nutritional approaches. Most dietary advises are indeed empirical and often lead to exclusion diets, reinforcing in patients the perception of “being intolerant” to food and self-perpetuating some of the very mechanisms underlying dyspepsia physiopathology (i.e., hypervigilance and symptom anticipation). Clinicians are often uncertain regarding the contribution of specific foods to dyspepsia physiopathology and dedicated professionals (i.e., dietitians) are only available in tertiary referral settings. This in turn, can result in nutritionally unbalanced diets and could even encourage restrictive eating behaviors in severe dyspepsia. In this review, we aim at evaluating the relationship between dietary habits, macronutrients and specific foods in determining FD symptoms. We will provide an overview of the evidence-based nutritional approach that should be pursued in these patients, providing clinicians with a valuable tool in standardizing nutritional advises and discouraging patients from engaging into indiscriminate food exclusions.

Postprandial Symptoms in Patients With Functional Dyspepsia and Irritable Bowel Syndrome: Relations to Ultrasound Measurements and Psychological Factors

Background/Aims

Dyspeptic symptoms are common in patients with functional gastrointestinal (GI) disorders, and may be related to visceral hypersensitivity. We aim to explore the relation between visceral hypersensitivity by using an ultrasonographic meal test and questionnaires in patients with irritable bowel syndrome (IBS) and/or functional dyspepsia (FD).

Methods

Patients (FD, n = 94; IBS, n = 88; IBS + FD, n = 66, healthy controls [HC], n = 30) were recruited consecutively and examined with ultrasound of the proximal and distal stomach after drinking 500 mL of a low caloric meat soup, and scored dyspeptic symptoms on a visual analogue scale (0-100 mm) before and after the meal. Psychological symptoms were assessed by Visceral Sensitivity Index (GI specific anxiety, n = 58), and Eysenck's Personality Questionnaire-neuroticism (EPQ-N, n = 203).

Results

Patients with IBS and/or FD reported higher levels of nausea, upper GI discomfort, and epigastric pain both before and after a liquid meal compared to HC (P < 0.001), and had a larger antral area in a fasting state, compared to HC. We found impaired accommodation in 33% of the patients with FD, however ultrasound measurements and symptom severity did not correlate. Symptoms of epigastric pain, fullness and upper GI discomfort positively correlated to Visceral Sensitivity Index and EPQ-N in a fasting state, but not postprandially.

Conclusions

Nausea, upper GI discomfort, and epigastric pain was common in patients with IBS and FD. Both patient groups had enlarged antral area in a fasting state compared to HC. Discomfort and pain were associated to GI specific anxiety and neuroticism in a fasting state.

Nissen fundoplication and dyspeptic symptoms: is the water load test useful?

BACKGROUND

The water load test is a simple, cheap and standardized method to evaluate gastric distension and gastric motility responses. We have previously shown that in patients with mild erosive or non-erosive esophagitis this test is frequently abnormal, suggesting an altered gastric function. The aim was to evaluate the water load test score before and after Nissen fundoplication in reflux patients.

METHODS

Thirty-one patients (16 men, 15 women, mean age 46.5 y) were studied before and 3 months after Nissen fundoplication by stationary esophageal manometry, wireless Bravo pH system monitoring (48 hours), and water load test. A dyspepsia symptom questionnaire was also completed before and after surgery. Data were compared with those of 35 controls.

RESULTS

All patients had pH-monitoring positive for pathological acid exposure and/or related-reflux symptoms in the absence of motility disorders. Basal symptoms scores were higher in patients compared to controls and improved after surgery, except than postprandial fullness, early satiation, and bloating, that were significantly increased. At baseline, all patients ingested significantly lower water volumes than controls, with a tendency to early onset of fullness and nausea, respectively. After surgery, the water volumes were significantly lower than presurgery.

CONCLUSIONS

In patients with reflux-related symptoms, with or without esophagitis, the water load test is frequently abnormal, suggesting an altered gastric function. Nissen fundoplication is associated with a relatively higher incidence of bloating, epigastric pain and fullness. These preliminary data could explain the incomplete resolution of symptoms after surgery in some patients, and suggest the use of additional studies to explore the gastric function in presurgical evaluation.

Quantitative MRI evaluation of gastric motility in patients with Parkinson's disease: Correlation of dyspeptic symptoms with volumetry and motility indices

Objective

To investigate the correlation between dyspeptic symptoms and gastric motility parameters measured by magnetic resonance imaging (MRI) using volumetry and motility indices in patients with Parkinson’s disease (PD).

Materials and methods

In this IRB-approved study, MRI datasets obtained from August 2014 to May 2016 in 38 PD patients were retrospectively analyzed. Patients underwent a 120-minute-long MRI study using a liquid test meal and 8 sets of scans. Gastric content volume (GCV) and total volume (TGV), gastric half emptying time (T_1/2), motility index (GMI), accommodation (GA), and emptying (GE) values were acquired. These measurements were compared between patients according to the presence of gastric symptoms: early satiety (n = 25), epigastric pain (n = 13), and dyspepsia (n = 28).

Results

Patients with early satiety showed significantly decreased GE of GCV and TGV (p < 0.001 and p = 0.017). Dyspeptic patients had significantly decreased GE of GCV and GMI (p = 0.001 and p = 0.029). GE of GCV at 90 and 120 minutes were significantly lower in patients with early satiety (p = 0.001 and p = 0.002). GE of GCV and GMI at 90 minutes were significantly decreased in patients with dyspepsia (p = 0.004 and p = 0.002). T_1/2 of GCV was prolonged in patients with early satiety, epigastric pain, and dyspepsia (p = 0.004, p = 0.041, and p = 0.023). T_1/2 of TGV also delayed in patients with early satiety (p = 0.023). GMI at 90 minutes was significantly correlated with dyspepsia on multivariable analysis (p = 0.028).

Conclusions

Gastric motility can be quantitatively assessed by MRI, showing decreased GMI, delayed GE, and prolonged T_1/2 in PD patients with early satiety or dyspepsia.

Biological Response to Meal Ingestion: Gender Differences

In a previous study, we demonstrated that women enjoyed and tolerated lower meal loads than men. Hence, we hypothesized that with the same meal load, their postprandial response is more pronounced than in men. We performed a randomized parallel trial in 12 women and 12 men comparing the postprandial responses to a palatable comfort meal. We measured homeostatic sensations (hunger/satiety, fullness) and hedonic sensations (digestive well-being, mood) on 10 cm scales, vagal tone by heart ratio variability and the metabolomic profile before and after meal ingestion. Gender differences were analyzed by repeated measures ANCOVA. Overall (n = 24), ingestion of the probe meal induced satiation, fullness, digestive well-being and improved mood (main time-effect p ≤ 0.005 for all). Women exhibited a more intense sensory experience, specially more postprandial fullness, than men [main gender-effect F (1, 21) = 7.14; p = 0.014]; hedonic responses in women also tended to be stronger than in men. Women exhibited more pronounced effects on vagal tone [main gender-effect F (1, 21) = 5.5; p = 0.029] and a different lipoprotein response than men. In conclusion, our data indicate that gender influences the responses to meal ingestion, and these differences may explain the predisposition and higher incidence in women of meal-related functional disorders.

Do body-related sensations make feel us better? Subjective well-being is associated only with the subjective aspect of interoception

According to the proposition of several theoretical accounts, the perception of the bodily cues, interoceptive accuracy and interoceptive sensibility, has a significant positive impact on subjective well-being. Others assume a negative association; however, empirical evidence is scarce. In this study, 142 young adults completed questionnaires assessing subjective well-being, interoceptive sensibility, and subjective somatic symptoms and participated in measurements of proprioceptive accuracy (reproduction of the angle of the elbow joint), gastric sensitivity (water load test), and heartbeat tracking ability (Schandry task). Subjective well-being showed weak to medium positive associations with interoceptive sensibility and weak negative associations with symptom reports. No associations with measures of interoceptive accuracy were found. Gastric sensitivity as opposed to heartbeat perception and proprioceptive accuracy moderated the association between interoceptive sensibility and well-being. Thus, subjective well-being is associated only with the self-reported (perceived) aspect of interoception but not related to the sensory measures of interoceptive accuracy.

Meal Enjoyment and Tolerance in Women and Men

Various conditioning factors influence the sensory response to a meal (inducible factors). We hypothesized that inherent characteristics of the eater (constitutive factors) also play a role. The aim of this proof-of-concept study was to determine the role of gender, as an individual constitutive factor, on the meal-related experience. Randomized parallel trial in 10 women and 10 men, comparing the sensations before, during, and after stepwise ingestion of a comfort meal up to full satiation. Comparisons were performed by repeated Analysis of Covariance (ANCOVA) measures. During stepwise ingestion, satisfaction initially increased up to a peak, and later decreased down to a nadir at the point of full satiation. Interestingly, the amount of food consumed at the well-being peak was lower, and induced significantly less fullness in women than in men. Hence, men required a larger meal load and stronger homeostatic sensations to achieve satisfaction. The same pattern was observed at the level of full satiation: men ate more and still experienced positive well-being, whereas in women, well-being scores dropped below pre-meal level. The effect of gender on the ingestion experience suggests that other constitutive factors of the eater may also influence responses to meals.

Towards a Fuller Assessment of Gastric Motility in Patients With Upper GI Dyspepsia: Time to Accommodate!

There is increasing recognition of the importance of assessing patients with unexplained upper gastrointestinal symptoms for impaired gastric accommodation. New therapeutic approaches to treat impaired accommodation are being developed. This increasing interest in diagnosing and treating impaired gastric accommodation emphasizes the need to have a clinically available method to measure the gastric accommodation response. In this editorial, gastric accommodation is discussed along with the currently available methods for its assessment. We summarize our thoughts on what are the next steps needed to make a readily accessible method for assessing gastric accommodation more widely available.

Multichannel Investigation of Interoception: Sensitivity Is Not a Generalizable Feature

Objective: The term interoception refers to the perception of bodily cues. In empirical studies, it is assessed using heartbeat detection or tracking tasks, often with the implicit assumption that cardioception reflects general interoceptive ability. Studies that applied a multichannel approach measured only a limited number of modalities. In the current study, six modalities were assessed to gain a deeper understanding of the relationship between the different sensory channels of interoception. Methods: For 118 university students (53% male) gastric perception (water load test), heartbeat perception (Schandry task), proprioception (elbow joint), ischemic pain (tourniquet technique), balancing ability (one leg stand), and perception of bitter taste were measured. Pair-wise correlation analysis and exploratory factor analyses (principal component analysis (PCA) and maximum likelihood (ML) extraction with oblimin rotation) were then carried out with a three-factor solution to investigate the underlying associations. Results: Correlation analysis only revealed significant associations between variables belonging to the same sensory modality (gastric perception, pain, bitter taste). Similarly, the three factors that consistently emerged in the factor analyses represented the three aforementioned modalities. Discussion: Interoceptive sensitivity assessed by using one channel only cannot be generalized. Interoceptive modalities carrying crucial information for survival are not integrated with other channels.

Definition, Pathogenesis, and Management of That Cursed Dyspepsia

Dyspepsia is an umbrella term used to encompass a number of symptoms thought to originate from the upper gastrointestinal tract. These symptoms are relatively nonspecific; not surprisingly, therefore, a myriad of conditions may present with any one or a combination of these symptoms. Therein lays the clinician's first challenge: detecting the minority who may have a potentially life-threatening disorder, such as gastric cancer, from a population whose symptoms are, for the most part, considered functional in origin. The second challenge lies in the definition and management of those individuals with functional dyspepsia (FD); the major focus of this review. The Rome process has addressed the issue of FD definition and a look back at the evolution of Rome criteria for this disorder illustrates the complexities that have so frustrated us. There has been no shortage of hypotheses to explain symptom pathogenesis in FD; initially focused on gastric sensorimotor dysfunction, these have now strayed well into the duodenum and have come to entertain such factors as immune responses and the microbiome. FD has proven to be an equally challenging area for therapeutics; while the staple approaches of acid suppression and eradication of Helicobacter pylori have some limited efficacy in select populations, strategies to ameliorate symptoms in the majority of sufferers based on presumed pathophysiology have largely foundered. Lacking a validated biomarker(s) FD continues to be an elusive target and is likely to remain so until we can better define the various phenotypes that it must surely contain.

Gastric accommodation in healthy subjects studied by ultrasound, manometry, and impedancemetry

BACKGROUND

Gastric accommodation to a meal may be important in the pathogenesis of upper gastrointestinal disorders, but has been difficult to investigate in a minimally invasive fashion.

METHODS

We studied gastric and lower esophageal physiology during food intake, combining transabdominal ultrasound, multichannel high-resolution impedance-manometry (HRIM) and a symptom questionnaire. A HRIM catheter was distally positioned at incisura angularis and 300 mL saline with 75 g glucose was ingested. Target variables were recorded for 30 min after fluid intake.

KEY RESULTS

Fifteen healthy subjects' participated (11W/4M, median age 23.8 y) and all accepted the meal with few symptoms. At incisura angularis maximum change in pressure from pre-intake values was -7.4 mmHg after 60 s (P < .0001), rising to pre-intake values within 20 min. The corresponding area increased significantly from pre-intake values of 8.0 cm² to 14.1 cm² shortly after intake (P = .0012), peaked at 5 min and slowly decreased towards 30 min. The corresponding maximum change in stress from pre-intake pressure values was -59.2 mmHg shortly after (P < .0001), reaching pre-intake values within 20 min. Strain rose from 0 shortly before to 0.36 shortly after (P < .0001), peaking at 5 min. At incisura angularis, fullness was positively correlated with area and to strain, while fullness, area, and stress were negatively correlated with pressure.

CONCLUSIONS & INFERENCES

The multimodal method enabled assessment of the gastric accommodation reflex, stress and strain in the stomach. It triggered few symptoms in healthy volunteers. We propose it to be a more physiological replacement of the barostat technique.

Nutrient drink test: Normative values in Indian children

BACKGROUND

Nutrient drink test (NDT) is a simple, non-invasive method to assess gastric function including accommodation. However, data on normal satiety drink volume (SDV) in children is scanty with no information about postprandial symptoms (PPS). Our aims were to establish normal values of NDT in healthy children and evaluate its correlation with age, gender, and anthropometry.

METHODS

Six- to 18-year-old healthy children underwent the NDT. The nutrient drink (0.94 kcal/mL) was given at a constant rate of 15 mL/min in 6-12-year-old subjects and at 30 mL/min in 13-18-year-old subjects till satiety score of 5 was reached. Postprandial symptoms (30 min) of fullness, nausea, bloating, and pain were scored using a visual analogue scale (0-100 mm) individually and as aggregate score.

RESULTS

Sixty-seven children (40 boys, age 12 [6-18 years]) were enrolled. Median SDV was 360 [180-960 mL], higher in 13-18-year-olds in comparison to 6-12-year-old children (360 [240-1002] vs. 300 [148-960] mL; p=0.005). SDV showed significant correlation with age, weight, and height. SDV was higher in boys than girls (450 [240-1074] vs. 330 [240-480] mL; p=0.02) in the older children (13-18 y), but it was similar in the younger children. Mild fullness (40 [0-80]) was the only PPS seen in 85% children and none had pain. PPS were not different between boys and girls or younger and older children.

CONCLUSION

The study provides normative data of SDV and PPS by NDT in 6-18-year-old children. SDV correlated with age and was higher in adolescent boys than girls.

Brain networks associated with cognitive and hedonic responses to a meal

BACKGROUND

We recently reported interrelated digestive, cognitive, and hedonic responses to a meal. The aim of this study was to identify brain networks related to the hedonic response to eating.

METHODS

Thirty-eight healthy subjects (20-38 age range) were evaluated after a 5-hour fast and after ingestion of a test meal (juice and warm ham and cheese sandwich, 300 mL, 425 kcal). Perceptual and affective responses (satiety, abdominal fullness, digestive well-being, and positive mood), and resting scans of the brain using functional MRI (3T Trio, Siemens, Germany) were evaluated immediately before and after the test meal. A high-order group independent component analysis was performed to investigate ingestion-related changes in the intrinsic connectivity of brain networks, with a focus on thalamic and insular networks.

KEY RESULTS

Ingestion induced satiation (3.3±0.4 score increase; P<.001) and abdominal fullness (2.4±0.3 score increase; P<.001). These sensations included an affective dimension involving digestive well-being (2.8±0.3 score increase; P<.001) and positive mood (1.8±0.2 score increase; P<.001). In general, thalamo-cortical connectivity increased with meal ingestion while insular-cortical connectivity mainly decreased. Furthermore, larger meal-induced changes (increase/decrease) in specific thalamic connections were associated with smaller changes in satiety/fullness. In contrast, a larger meal-induced decrease in insular-anterior cingulate cortex connectivity was associated with increased satiety, fullness, and digestive well-being.

CONCLUSIONS AND INFERENCES

Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion.

The Intragastric Pressure Measurement: A Novel Method to Assess Gastric Accommodation in Functional Dyspepsia Children

BACKGROUND

Impaired gastric accommodation (GA) is proposed as a main pathophysiological mechanism for functional dyspepsia (FD). At present, the gastric barostat is the criterion standard to measure GA. Hence, this procedure is invasive and it may alter gastric physiology. Recently, we proposed the measurement of intragastric pressure (IGP) by means of high-resolution manometry during nutrient intake as a potential alternative for assessing GA in adults.

OBJECTIVES

Our aim was first to study the feasibility of the IGP measurement with nutrient tolerance in children with FD and second to compare these results with young healthy adults.

METHODS

A high-resolution manometry probe and a feeding tube were positioned in the proximal stomach. The IGP was measured before and during intragastric infusion of a nutrient drink (ND, 300 kcal, 60 mL/min). Subjects were asked to score their satiation and epigastric symptoms. The test ended when the subjects scored maximal satiation.

RESULTS

A total of 15 healthy volunteers (HVs, 21.7 ± 4.7 years, 21.1 ± 0.3 kg/m) and 17 patients with FD (14.4 ± 0.7 years, 19.6 ± 0.7 kg/m) participated. Patients with FD experienced mainly from postprandial fullness (86%), epigastric pain (71%), and bloating (62%). In both groups, intragastric infusion of ND induced a drop in IGP (area above the IGP curve FD: -15.5 ± 3.5 mmHg vs HVs: -18.0 ± 8.7 mmHg; P = 0.57). Patients showed impaired nutrient tolerance compared with HVs (587.6 ± 80.2 vs 936 ± 66.2 kcal; P = 0.003). All patients and HVs tolerated the catheters and could finalize the study.

CONCLUSIONS

The measurement of IGP during intragastric ND infusion was well tolerated in children. Nutrient tolerance was reduced in children with FD compared with HVs. In the future, this may be a useful tool to assess GA accommodation and nutrient tolerance in children.

Upper GI Disorders: Pathophysiology and Current Therapeutic Approaches

Symptoms referable to the upper digestive tract are associated with abnormalities of upper gastric neuromuscular function including abnormalities of motility, sensation, and absorption. Of the upper digestive tract, the stomach is of particular importance in its role in symptom generation and is highlighted in this chapter. Gastric symptoms can be associated with alterations in the rates of gastric emptying, impaired accommodation, heightened gastric sensation, or alterations in gastric myoelectrical activity and contractility. Treatment of gastric neuromuscular disorders requires an understanding of pathophysiology of the disorders, the appropriate use and interpretation of diagnostic tests, and the knowledge of effective treatment options. This chapter covers the pathophysiology and current treatment approaches to disorders of the upper gastrointestinal tract, focusing on classic disorders of the stomach, particularly gastroparesis and functional dyspepsia.

The Water Load Test As a Measure of Gastric Interoception: Development of a Two-Stage Protocol and Application to a Healthy Female Population

The sensitivity for one’s own internal body signals (i.e., interoception) has been demonstrated to play an important role in the pathogenesis of eating and weight disorders. Most previous measures assessing interoceptive processing have not, or only partly, captured perception of hunger and satiety cues, which is a core aspect of interoceptive deficits in eating disorders. In addition, methods used to measure sensitivity to gastric signals are heterogeneous and findings inconsistent. The primary aim of the present study was to establish a standardised test to measure gastric interoception, and to provide normative data using a non-clinical adult sample. The two-step Water Load Test (WLT-II) involves ingestion of non-caloric water until perceived satiation (step 1) and until maximum fullness (step 2). The WLT-II consists of several variables: Besides volumes of water ingested until satiation and maximum fullness expressed in ml, percentage of satiation to maximum fullness is calculated as an individual index of gastric interoception that is not confounded with stomach capacity. Ninety-nine healthy women participated in the study. Measures included the WLT-II, the heartbeat tracking test, a self-report questionnaire assessing subjective sensations, and the Eating Disorder Inventory-2. Twenty-eight participants underwent test-retest of the WLT-II. Results suggest that the WLT-II is a valid and reliable measure of gastric interoception. Importantly, satiation volume and percentage of satiation to maximum fullness were strongly positively related to self-reported bulimic symptoms, indicating that the WLT-II could emerge as a useful clinical tool to measure interoceptive processing in the field of eating disorders.

Women and functional dyspepsia

Functional dyspepsia is relatively common yet poorly understood. The best accepted diagnostic criteria are the Rome III criteria. The epidemiology, healthcare seeking rates, impact and pathophysiology are reviewed with a focus on women. Treatment is limited with no clearly established regimen currently recommended. Duodenal eosinophilia may be found in a subset. Proton pump inhibitors and prokinetic agents represent the standard therapeutic regimen after Helicobacter pylori infection has been eliminated. Some novel agents such as the prokinetic acotiamide appear promising; however, the need for a safe and efficacious treatment remains largely unmet. This review also describes the currently available management options for functional dyspepsia.

Effect of Amitriptyline and Escitalopram on Functional Dyspepsia: A Multicenter, Randomized Controlled Study

BACKGROUND & AIMS

Antidepressants are frequently prescribed to treat functional dyspepsia (FD), a common disorder characterized by upper abdominal symptoms, including discomfort or postprandial fullness. However, there is little evidence of the efficacy of these drugs in patients with FD. We performed a randomized, double-blind, placebo-controlled trial to evaluate the effects of antidepressant therapy on symptoms, gastric emptying (GE), and meal-induced satiety in patients with FD.

METHODS

We performed a study at 8 North American sites of patients who met the Rome II criteria for FD and did not have depression or use antidepressants. Patients (n = 292; 44 ± 15 years old, 75% were female, 70% with dysmotility-like FD, and 30% with ulcer-like FD) were randomly assigned to groups given placebo, 50 mg amitriptyline, or 10 mg escitalopram for 10 weeks. The primary end point was adequate relief of FD symptoms for ≥5 weeks of the last 10 weeks (of 12). Secondary end points included GE time, maximum tolerated volume in Nutrient Drink Test, and FD-related quality of life.

RESULTS

An adequate relief response was reported by 39 subjects given placebo (40%), 51 given amitriptyline (53%), and 37 given escitalopram (38%) (P = .05, after treatment, adjusted for baseline balancing factors including all subjects). Subjects with ulcer-like FD given amitriptyline were >3-fold more likely to report adequate relief than those given placebo (odds ratio = 3.1; 95% confidence interval: 1.1-9.0). Neither amitriptyline nor escitalopram appeared to affect GE or meal-induced satiety after the 10-week period in any group. Subjects with delayed GE were less likely to report adequate relief than subjects with normal GE (odds ratio = 0.4; 95% confidence interval: 0.2-0.8). Both antidepressants improved overall quality of life.

CONCLUSIONS

Amitriptyline, but not escitalopram, appears to benefit some patients with FD, particularly those with ulcer-like (painful) FD. Patients with delayed GE do not respond to these drugs. ClinicalTrials.gov ID: NCT00248651.

Digestive, cognitive and hedonic responses to a meal

BACKGROUND

Gut dysfunctions may be associated to digestive symptoms. We hypothesized that the gut can also originate pleasant sensations, and wished to demonstrate the hedonic component of the digestive response to a meal.

METHODS

Healthy subjects (n = 42) were evaluated during basal fasting conditions and during experimentally induced fullness sensation (either by gastric distension or duodenal nutrient infusion). In each set of studies, a 240 mL test meal (12 kcal broth) and water, as inert control meal, were administered on separate days in a randomized, cross-over design. Gastric accommodation, the cognitive response and the hedonic dimension (both by 10 score scales) were measured 9 min before and 60 min after the meal.

KEY RESULTS

In basal conditions, the test meal induced a significantly greater gastric relaxation than the control meal (166 ± 28 mL isotonic volume increase 67 ± 14 mL; p = 0.002). Both meals induced epigastric fullness (3.8 ± 0.7 score and 3.2 ± 0.8 score, respectively; p = 0.740), but contrary to the inert meal, with the active meal this conscious sensation had a pleasant dimension (digestive comfort increase by 1.3 ± 0.6 score with active meal vs -1.1 ± 0.6 decrease with inert meal; p = 0.015). Experimentally induced fullness was associated to a decrease in digestive well-being or abdominal discomfort, which improved only after the active meal but not the inert meal.

CONCLUSIONS & INFERENCES

When appropriate conditions are met, the response to a meal includes a hedonic dimension involving pleasant sensation of digestive well-being.

Applying novel nutrient drink to clinical trial of functional dyspepsia

Background/Aims

The drink test has been regarded as a surrogate marker of gastric accommodation. The aims of this study were to develop a novel nutrient drink test (NDT) protocol and investigate its potential for application to a clinical trial of functional dyspepsia (FD).

Methods

A novel NDT was designed, involving drinking 125 mL of nutrient 4 times at 5-minute intervals or until maximal tolerability. Healthy volunteers and patients with FD rated their symptoms every 5 minutes for 20 minutes in a developmental study. Patients with FD were enrolled in an open trial of itopride for 4 weeks. NDT was performed before and after treatment. Improvement of integrative symptoms score during NDT after treatment for more than 50% compared with baseline was defined as responder.

Results

Total aggregate symptom scores, sum of symptom scores measured during NDT, were higher in FD patients (n = 40, 368.1 ± 245.3) than in controls (n = 19, 215.9 ± 171.2) (P = 0.018) in a developmental study. In an open trial of itopride, symptom scores measured during NDT decreased significantly at all time points after treatment in responders (n = 49), whereas did not in non-responders (n = 25). Total aggregate symptom score for NDT correlated significantly with integrative dyspeptic symptom score, sum of 8 symptom scores of NDI questionnaire, at baseline (r = 0.374, P = 0.001) and after treatment (r = 0.480, P < 0.001).

Conclusions

Our novel NDT can quantify dyspeptic symptoms and reflected therapeutic effects of itopride treatment in a clinical trial of FD patients. This NDT can be used as an effective parameter in clinical trials or drug development programs for assessing effects of novel therapies on postprandial symptoms.

Mechanisms of postprandial abdominal bloating and distension in functional dyspepsia

OBJECTIVE

Patients with irritable bowel syndrome and abdominal bloating exhibit abnormal responses of the abdominal wall to colonic gas loads. We hypothesised that in patients with postprandial bloating, ingestion of a meal triggers comparable abdominal wall dyssynergia. Our aim was to characterise abdominal accommodation to a meal in patients with postprandial bloating.

DESIGN

A test meal (0.8 kcal/ml nutrients plus 27 g/litre polyethylenglycol 4000) was administered at 50 ml/min as long as tolerated in 10 patients with postprandial bloating (fulfilling Rome III criteria for postprandial distress syndrome) and 12 healthy subjects, while electromyographic (EMG) responses of the anterior wall (upper and lower rectus, external and internal oblique via bipolar surface electrodes) and the diaphragm (via six ring electrodes over an oesophageal tube in the hiatus) were measured. Means +/- SD were calculated.

RESULTS

Healthy subjects tolerated a meal volume of 913±308 ml; normal abdominal wall accommodation to the meal consisted of diaphragmatic relaxation (EMG activity decreased by 15±6%) and a compensatory contraction (25±9% increase) of the upper abdominal wall muscles (upper rectus and external oblique), with no changes in the lower anterior muscles (lower rectus and internal oblique). Patients tolerated lower volume loads (604±310 ml; p=0.030 vs healthy subjects) and developed a paradoxical response, that is, diaphragmatic contraction (14±3% EMG increment; p<0.01 vs healthy subjects) and upper anterior wall relaxation (9±4% inhibition; p<0.01 vs healthy subjects).

CONCLUSIONS

In functional dyspepsia, postprandial abdominal distension is produced by an abnormal viscerosomatic response to meal ingestion that alters normal abdominal accommodation.

Progress in measurements of proximal gastric accommodation in patients with functional dyspepsia

Since gastric accommodation is an important parameter for investigating the pathophysiology of functional dyspepsia, the measurement of gastric accommodation has aroused widespread interests. Gastric barostat remains the gold standard, but it needs intubation and is invasive. In recent years, emerging modalities including single photon emission computed tomography (SPECT), three-dimensional ultrasound and magnetic resonance imaging have been developed to measure gastric volumes accurately and non-invasively; however, these technologies are sophisticated and expensive, which limits their clinical application. The satiety drinking test is simple and non-invasive and is often used in clinical and research studies, but the differences in the types of meals and the drinking speed among different studies often cause differences in the evaluation of gastric accommodation. The aim of this review is to summarize the advantages and disadvantages of various measurements of gastric accommodation.

Decreased Basal and postprandial plasma serotonin levels in patients with functional dyspepsia

BACKGROUND & AIMS

Patients with diarrhea-predominant irritable bowel syndrome (IBS) have been found to have increased postprandial levels of serotonin (5-HT). Functional dyspepsia (FD) and IBS have been proposed to have common methods of pathogenesis, but little is known about the role of 5-HT in FD.

METHODS

We measured postprandial levels of 5-HT in 54 patients with FD (based on Rome III criteria) and 28 asymptomatic healthy individuals (controls). Patients with gastroesophageal reflux disease and IBS as their predominant symptom were excluded. After an overnight fast, the subjects drank a liquid meal (Ensure; 1.06 kcal/mL at 30 mL/min) and underwent a (13)C-octanoic acid breath test to measure gastric emptying times. Blood samples were collected at 0, 30, 60, 90, and 120 minutes after the liquid meal for the 5-HT assay.

RESULTS

Thirty-five patients with FD (65%) had postprandial distress syndrome, and 6 (11%) had a combination of postprandial distress syndrome and epigastric pain syndrome. There were no differences in rates of gastric emptying between patients with FD (103.6 ± 19.4 minutes) and controls (83.1 ± 4.0 minutes; P = .30). However, patients with FD had lower caloric intake (823.40 ± 44.1 kcal) than controls (1021 ± 68.2 kcal; P = .026). Patients with FD also had lower basal (P = .03) and postprandial plasma levels of serotonin at 30 minutes (P = .04), 60 minutes (P = .01), 90 minutes (P = .02), and 120 minutes (P = .002) than controls, as well as area under the curve values over the 120-minute time period (P = .005). Repeated-measures analysis of variance correlated 5-HT level with FD (P < .001).

CONCLUSIONS

In contrast to patients with diarrhea-predominant IBS, those with FD have decreased basal and postprandial plasma levels of 5-HT. These findings indicate that the pathogenic mechanism of FD differs from that of diarrhea-predominant IBS, and that strategies to alter 5-HT levels or activity might be developed to treat patients with FD.

[Functional dyspepsia and the satiety test: its usefulness in clinical practice]

INTRODUCTION

According to the Rome III Criteria, functional dyspepsia (FD) is classified as postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). On the other hand, the satiety test (ST) has been used to evaluate gastric accommodation and emptying, distinguishing healthy individuals from those with dyspepsia.

AIMS

To determine whether the ST can distinguish dyspeptic individuals from healthy ones and to evaluate its usefulness in differentiating the two FD subtypes.

METHODS

Adults with FD were consecutively enrolled in a cross-sectional study within the time frame of August 2011 and October 2012. Healthy subjects participated as controls. The ST consisted of the intake of a nutritional supplement (Fortisip®, Nutricia Bagó®) at a constant speed; satiety was graded at 5-minute intervals (1 to 5 points). Intake was suspended when the maximum score was reported. The total ingested volume and caloric intake was recorded and the Mann-Whitney U test was used in the statistical analysis.

RESULTS

The study included 39 dyspeptic patients and 20 control individuals. The patients were predominantly women (84.6 vs. 25%; p < 0.0001) and they were similar in age (39.59 ± 13.53 vs. 34.70 ± 9.85 years) and BMI (24.32 ± 3.52 vs. 25.82 ± 3.34 kg/m2) with respect to the controls. The FD subtype percentages were PDS: 61%, EPS: 31%, and Mixed syndrome: 8%. There was a lower ingested volume and caloric intake on the part of the dyspeptic patients (185 vs. 300 ml and 277 vs. 520 Kcal, respectively. Both: P<.001). No differences in the ST were observed between the two pure dyspepsia subtypes.

CONCLUSIONS

There was a difference in the ST between healthy individuals and those with dyspepsia, but the ingested volume and caloric intake in the two FD subtypes were similar.

Dietary lipids and functional gastrointestinal disorders

There is convincing evidence that patients with functional gastrointestinal disorders (FGIDs) exhibit dysfunctions of the gut involving hypersensitivity and abnormal reflexes, so that physiological, normally unperceived, stimuli induce symptoms. The type of symptoms depends on the specific sensory-reflex pathways and region(s) affected. Fat modulates the responses of the gut to various stimuli, and some of these modulatory mechanisms are abnormal in patients with FGIDs. Indeed, laboratory-based studies have shown that the symptoms experienced by these patients can be induced, or exacerbated, by administration of lipids in amounts that are well tolerated by healthy controls, and, thus, demonstrate a hypersensitivity to lipid. Very few studies have evaluated dietary patterns and eating behavior in these patients, with often-conflicting outcomes, and no studies have been performed to evaluate the role of targeted dietary interventions for the relief of symptoms. Given the evidence from laboratory studies, as well as patient experience, such studies, in large cohorts of patients, are needed with the view to develop personalized, cost-effective treatment approaches.

Inhibition of gastric perception of mild distention by omeprazole in volunteers

AIM: To evaluate the effects of omeprazole on gastric mechanosensitivity in humans.

METHODS: A double lumen polyvinyl tube with a plastic bag was introduced into the stomach of healthy volunteers under fluorography and connected to a barostat device. Subjects were then positioned so they were sitting comfortably, and the minimal distending pressure (MDP) was determined after a 30-min adaptation period. Isobaric distensions were performed in stepwise increments of 2 mmHg (2 min each) starting from the MDP. Subjects were instructed to score feelings at the end of every step using a graphic rating scale: 0, no perception; 1, weak/vague; 2, weak but significant; 3, moderate/vague; 4, moderate but significant; 5, severe discomfort; and 6, unbearable pain. After this first test, subjects received omeprazole (20 mg, after dinner) once daily for 1 wk. A second test was performed on the last day of treatment.

RESULTS: No adverse effects were observed. Mean MDP before and after treatment was 6.3 ± 0.3 mmHg and 6.2 ± 0.5 mmHg, respectively. One subject before and 2 after treatment did not reach a score of 6 at the maximum bag volume of 750 mL. After omeprazole, there was a significant increase in the distension pressure required to reach scores of 1 (P = 0.019) and 2 (P = 0.017) as compared to baseline. There were no changes in pressure required to reach the other scores after treatment. Two subjects before and one after omeprazole rated their abdominal feeling < 1 at MDP, and mean (± SE) abdominal discomfort scores at MDP were 0.13 ± 0.09 and 0.04 ± 0.04, respectively. Mean scores induced by each MDP + 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 (mmHg) were 1.1 ± 0.3, 2.0 ± 0.4, 2.9 ± 0.5, 3.3 ± 0.4, 4.6 ± 0.3, 5.2 ± 0.3, 5.5 ± 0.2, 5.5 ± 0.3, 5.7 ± 0.3, and 5.4, respectively. After omeprazole, abdominal feeling scores for the same incremental pressures over MDP were 0.3 ± 0.1, 0.8 ± 0.1, 2.0 ± 0.4, 2.8 ± 0.4, 3.8 ± 0.4, 4.6 ± 0.4, 4.9 ± 0.3, 5.4 ± 0.4, 5.2 ± 0.6, and 5.0 ± 1.0, respectively. A significant decrease in feeling score was observed at intrabag pressures of MDP + 2 mmHg (P = 0.028) and + 4 mmHg (P = 0.013), respectively, after omeprazole. No significant score changes were observed at pressures ≥ MDP + 6 mmHg.

CONCLUSION: Although the precise mechanisms are undetermined, the present study demonstrated that omeprazole decreases mechanosensitivity to mild gastric distension.

Advancing gastric emptying studies: standardization and new parameters to assess gastric motility and function

For many years, gastric emptying (GE) studies were performed using various local protocols and different radiolabeled meals. This lack of standardization and normal values made the test results unreliable and difficult to compare from one site to another. A recent consensus has been published that now provides guidance and standardization on how to perform a radiolabeled solid-meal GE study. It is widely recognized, however, that simple measurement of total GE of a solid meal often does not provide an answer to the etiology of symptoms for a large number of patients who present with functional dyspepsia. Advances in our understanding of the different roles of the fundus and antrum and their complex interaction with the proximal small bowel and central nervous system have led to the development of new methods to study gastric motility. This review describes how a more comprehensive approach to studying GE is needed and how this will lead to better diagnosis and treatment for patients referred for GE studies.