Association between the Static and Dynamic Lung Function and CT-Derived Thoracic Skeletal Muscle Measurements-A Retrospective Analysis of a 12-Month Observational Follow-Up Pilot Study.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) with low skeletal muscle mass and severe airway obstruction have higher mortality risks. However, the relationship between dynamic/static lung function (LF) and thoracic skeletal muscle measurements (SMM) remains unclear. This study explored patient characteristics (weight, BMI, exacerbations, dynamic/static LF, sex differences in LF and SMM, and the link between LF and SMM changes. METHODS: A retrospective analysis of a 12-month prospective follow-up study patients with stable COPD undergoing standardized treatment, covering mild to severe stages, was conducted. The baseline and follow-up assessments included computed tomography and body plethysmography. RESULTS: This study included 35 patients (17 females and 18 males). This study revealed that females had more stable LF but tended to have greater declines in SMM areas and indices than males (-5.4% vs. -1.9%, respectively), despite the fact that females were younger and had higher LF and less exacerbation than males. A multivariate linear regression showed a negative association between the inspiratory capacity/total lung capacity ratio (IC/TLC) and muscle fat area. CONCLUSIONS: The findings suggest distinct LF and BC progression patterns between male and female patients with COPD. A low IC/TLC ratio may predict increased muscle fat. Further studies are necessary to understand these relationships better.

Ethnic differences in CT derived abdominal body composition measures: a comparative retrospect pilot study between European and Inuit study population.

Understanding ethnic variations in body composition is crucial for assessing health risks. Universal models may not suit all ethnicities, and there is limited data on the Inuit population. This study aimed to compare body composition between Inuit and European adults using computed tomography (CT) scans and to investigate the influence of demographics on these measurements. A retrospective analysis was conducted on 50 adults (29 Inuit and 21 European) who underwent standard trauma CT scans. Measurements focused on skeletal muscle index (SMI), various fat indices, and densities at the third lumbar vertebra level, analyzed using the Wilcoxon-Mann-Whitney test and multiple linear regression. Inuit women showed larger fat tissue indices and lower muscle and fat densities than European women. Differences in men were less pronouncehd, with only Intramuscular fat density being lower among Inuit men. Regression indicated that SMI was higher among men, and skeletal muscle density decreased with Inuit ethnicity and age, while visceral fat index was positively associated with age. This study suggests ethnic differences in body composition measures particularly among women, and indicates the need for Inuit-specific body composition models. It higlights the importance of further research into Inuit-specific body composition measurements for better health risk assessment.

MRI-Based Quantification of Pan-Alimentary Function and Motility in Subjects with Diabetes and Gastrointestinal Symptoms.

Background: Diabetes-induced gastrointestinal (GI) symptoms are common but difficult to correctly diagnose and manage. We used multi-segmental magnetic resonance imaging (MRI) to evaluate structural and functional GI parameters in diabetic patients and to study the association with their symptomatic presentation. Methods: Eighty-six participants (46 with diabetes and GI symptoms, 40 healthy controls) underwent baseline and post-meal MRI scans at multiple timepoints. Questionnaires were collected at inclusion and following the scans. Data were collected from the stomach, small bowel, and colon. Associations between symptoms and collected data were explored. Utilizing machine learning, we determined which features differentiated the two groups the most. Key Results: The patient group reported more symptoms at inclusion and during MRI scans. They showed 34% higher stomach volume at baseline, 40% larger small bowel volume, 30% smaller colon volume, and less small bowel motility postprandially. They also showed positive associations between gastric volume and satiety scores, gastric emptying time and reflux scores, and small bowel motility and constipation scores. No differences in gastric emptying were observed. Small bowel volume and motility were used as inputs to a classification tool that separated patients and controls with 76% accuracy. Conclusions: In this work, we studied structural and functional differences between patients with diabetes and GI symptoms and healthy controls and observed differences in stomach, small bowel, and colon volumes, as well as an adynamic small bowel in patients with diabetes and GI symptoms. Associations between recorded parameters and perceived symptoms were also explored and discussed.

Association between thoracic and third lumbar CT-derived muscle mass and density in Caucasian patients without chronic disease: a proof-of-concept study.

BACKGROUND: Computed tomography (CT) is increasingly used in the clinical workup, and existing scan contains unused body composition data, potentially useful in a clinical setting. However, there is no healthy reference for contrast-enhanced thoracic CT-derived muscle measures. Therefore, we aimed at investigating whether there is a correlation between each of the thoracic and third lumbar vertebra level (L3) skeletal muscle area (SMA), skeletal muscle index (SMI), and skeletal muscle density (SMD) at contrast-enhanced CT in patients without chronic disease. METHODS: A proof-of-concept retrospective observational study was based on Caucasian patients without chronic disease, who received CT for trauma between 2012 and 2014. Muscle measures were assessed using a semiautomated threshold-based software by two raters independently. Pearson's correlation between each thoracic level and third lumbar and intraclass correlation between two raters and test-retest with SMA as proxy parameters were used. RESULTS: Twenty-one patients (11 males, 10 females; median age 29 years) were included. The second thoracic vertebra (T2) had the highest median of cumulated SMA (males 314.7 cm2, females 118.5 cm2) and SMI (97.8 cm2/m2 and 70.4 cm2/m2, respectively). The strongest SMA correlation was observed between T5 and L3 (r = 0.970), the SMI between T11 and L3 (r = 0.938), and the SMD between the T10 and L3 (r = 0.890). CONCLUSIONS: This study suggests that any of the thoracic levels can be valid to assess skeletal muscle mass. However, the T5 may be most favourable for measuring SMA, the T11 for SMI, and T10 for SMD when using contrast-enhanced thoracic CT. RELEVANCE STATEMENT: In COPD patients, a CT-derived thoracic muscle mass assessment may help identify who would benefit from focused pulmonary rehabilitation: thoracic contrast-enhanced CT conducted as part of the standard clinical workup can be used for this evaluation. KEY POINTS: • Any thoracic level can be used to assess thoracic muscle mass. • Thoracic level 5 is strongly associated with the 3rd lumbar muscle area. • A strong correlation between the thoracic level 11 and the 3rd lumbar muscle index. • Thoracic level 10 is strongly associated with the 3rd lumbar muscle density.

Effects of opium tincture on the enteric and central nervous systems: A randomized controlled trial.

Opioids change gut motility, and opium tincture has been used for treatment of chronic diarrhoea for centuries. However, the effects have never been documented in controlled trials. We aimed to investigate the effects of opium tincture on gastrointestinal transit and motility, frequency of bowel movements, stool consistency, gastrointestinal symptoms and sedation. Twenty healthy subjects were included in this randomized controlled trial. Opium tincture or placebo was each applied for 9 days. Gastrointestinal transit and motility were investigated with the 3D-transit system. Bowel movements and gastrointestinal symptoms were recorded daily. General cognition, reaction time, memory and electroencephalography were used to assess effects on the central nervous system. Opium tincture doubled colonic transit (49 vs. 23 h, p < 0.001), decreased antegrade colonic movements (p < 0.05), reduced daily bowel movements (0.7 vs. 1.2, p < 0.001) and increased stool consistency (Type 3 vs. Type 4, p < 0.001). No changes in general cognition, reaction time or memory were observed, and minor changes of power observed by electroencephalography did not indicate sedation. This study is the first to show that opium tincture has anti-propulsive properties in the healthy gut, while no sedative effects were seen. This indicates that opium tincture is a relevant and safe treatment option in chronic diarrhoea.

A novel MRI-based three-dimensional model of stomach volume, surface area, and geometry in response to gastric filling and emptying.

BACKGROUND: Gastric motility and accommodation have a critical role in maintaining normal gastrointestinal homeostasis. Different modalities can be adopted to quantify those processes, that is, scintigraphy to measure emptying time and intragastric Barostat for accommodation assessment. However, magnetic resonance imaging (MRI) can assess the same parameters noninvasively without ionizing radiation. Our study aimed to develop a detailed three-dimensional (3D) MRI model of the stomach to describe gastric volumes, surface areas, wall tension distribution, and interobserver agreement. METHODS: Twelve healthy volunteers underwent an MRI protocol of six axial T2-weighted acquisitions. Each dataset was used to construct a 3D model of the stomach: First, the volumes of the whole stomach, gastric liquid, and air were segmented. After landmark placing, a raw 3D model was generated from segmentation data. Subsequently, irregularities were removed, and the model was divided into compartments. Finally, surface area and 3D geometry parameters (inverse curvatures) were extracted. The inverse curvatures were used as a proxy for wall tension distribution without measuring the intragastric pressure. KEY RESULTS: The model was able to describe changes in volume and surface geometry for each compartment with a distinct pattern in response to filling and emptying. The surface tension was distributed nonhomogeneously between compartments and showed dynamical changes at various time points. CONCLUSION & INFERENCES: The presented model offers a detailed tool for evaluating gastric volumes, surface geometry, and wall tension in response to filling and emptying and will provide insights into gastric emptying and accommodation in diseases such as diabetic gastroparesis.

Regional gastrointestinal transit times in patients with chronic pancreatitis.

The mechanisms behind disrupted gastrointestinal (GI) motor function in patients with chronic pancreatitis (CP) have not been fully elucidated. We compared regional transit times in patients with CP to those in healthy controls, and investigated whether they were associated with diabetes mellitus, exocrine dysfunction, opioid treatment or quality of life. Twenty-eight patients with CP and 28 age- and gender-matched healthy controls were included. Regional GI transit times were determined using the 3D-Transit system, which consists of an ingestible electromagnetic capsule and a detector worn in an abdominal belt for 5 days. Exocrine function was assessed using the fecal elastase-1 test, and quality of life was assessed using the European Organization for Research and Treatment of Cancer questionnaire. Transit times were analyzed for associations with diabetes mellitus, exocrine pancreatic insufficiency (EPI), opioid treatment and quality of life. Compared with healthy controls, patients with CP had prolonged transit times in the small intestine (6.6 ±â€…1.8 vs 4.8 ±â€…2.2 hours, P = .006), colon (40 ±â€…23 vs 28 ±â€…26 hours, P = .02), and total GI tract (52 ±â€…26 vs 36 ±â€…26 hours, P = .02). There was no difference in gastric emptying time (4.8 ±â€…5.2 vs 3.1 ±â€…1.3 hours, P = .9). No associations between transit times and diabetes, EPI, or opioid consumption were found (all P > .05). Quality of life and associated functional and symptom subscales were not associated with transit times, except for diarrhea (P = .03). Patients with CP have prolonged small intestinal and colonic transit times. However, these alterations do not seem to be mediated by diabetes, EPI, or opioid consumption.

Indentation of a pressurized silicon stomach model - A non-invasive study of gastric wall stiffness and pressurized gastric content stiffness.

BACKGROUND AND AIMS: Evaluation of gastric wall stiffness and intragastric pressure is essential for detailed assessments of gastric accommodation. However, non-invasive assessments are needed for large scale clinical studies and none of the existing methods takes abdominal wall effect into the calculation. This study aimed to assess gastric wall stiffness and gastric content stiffness as a proxy for intragastric pressure using novel mechanical modeling and non-invasive indentation tests on a silicon stomach model. METHODS: A silicon stomach model (scaling 1:1 with the human stomach) was indented using a pressure algometer at intragastric pressures from 0 to 0.8 kPa. Wall thicknesses and luminal cross-sectional areas along the stomach were measured with ultrasound images. The gastric wall stiffness was compared between measurements from tensile tests on strips cut from the silicon stomach and estimations from a shell indentation model. The pressurized gastric content stiffness was predicted from a bonded two-layer axisymmetric half-space indentation model. RESULTS: The gastric wall stiffness estimated from the shell indentation model showed no difference to measurements from the mechanical tests on the cutting strips (p = 0.14). The predicted gastric content stiffness was strongly associated with the intragastric pressure (r > 0.83, p < 0.001). CONCLUSIONS: The mechanical model developed in this study can simultaneously predict the gastric wall stiffness and the pressurized gastric content stiffness. In future studies, the method can be applied to reveal intragastric pressure conditions non-invasively via the pressurized gastric content stiffness during gastric accommodation and emptying such as with magnetic resonance imaging.

Central neuronal transmission in response to tonic cold pain is modulated in people with type 1 diabetes and severe polyneuropathy.

AIMS: This study aimed to investigate cortical source activity and identify source generators in people with type 1 diabetes during rest and tonic cold pain. METHODS: Forty-eight participants with type 1 diabetes and neuropathy, and 21 healthy controls were investigated with electroencephalography (EEG) during 5-minutes resting and 2-minutes tonic cold pain (immersing the hand into water at 2 °C). EEG power was assessed in eight frequency bands, and EEG source generators were analyzed using standardized low-resolution electromagnetic tomography (sLORETA). RESULTS: Compared to resting EEG, cold pain EEG power differed in all bands in the diabetes group (all p < 0.001) and six bands in the controls (all p < 0.05). Source generator activity in the diabetes group was increased in delta, beta2, beta3, and gamma bands and decreased in alpha1 (all p < 0.006) with changes mainly seen in the frontal and limbic lobe. Compared to controls, people with diabetes had decreased source generator activity during cold pain in the beta2 and beta3 bands (all p < 0.05), mainly in the frontal lobe. CONCLUSIONS: Participants with type 1 diabetes had altered EEG power and source generator activity predominantly in the frontal and limbic lobe during tonic cold pain. The results may indicate modulated central transmission and neuronal impairment.

Colonic volume in patients with functional constipation or irritable bowel syndrome determined by magnetic resonance imaging.

BACKGROUND: Functional constipation (FC) and irritable bowel syndrome constipation type (IBS-C) share many similarities, and it remains unknown whether they are distinct entities or part of the same spectrum of disease. Magnetic resonance imaging (MRI) allows quantification of intraluminal fecal volume. We hypothesized that colonic volumes of patients with FC would be larger than those of patients with IBS-C, and that both patient groups would have larger colonic volumes than healthy controls (HC). METHODS: Based on validated questionnaires, three groups of participants were classified into FC (n = 13), IBS-C (n = 10), and HC (n = 19). The colonic volume of each subject was determined by MRI. Stool consistency was described by the Bristol stool scale and colonic transit times were assessed with radiopaque makers. KEY RESULTS: Overall, total colonic volumes were different in the three groups, HC (median 629 ml, interquartile range (IQR)(562-868)), FC (864 ml, IQR(742-940)), and IBS-C (520 ml IQR(489-593)) (p = 0.001). Patients with IBS-C had lower colonic volumes than patients with FC (p = 0.001) and HC (p = 0.019), but there was no difference between FC and HC (p = 0.10). Stool consistency was similar in the two patient groups, but patients with FC had longer colonic transit time than those with IBS-C (117.6 h versus 43.2 h, p = 0.019). CONCLUSION: Patients with IBS-C have lower total colonic volumes and shorter colonic transit times than patients with FC. Future studies are needed to confirm that colonic volume allows objective distinction between the two conditions.

Quantification of gastric emptying with magnetic resonance imaging in healthy volunteers: A systematic review.

BACKGROUND: Several magnetic resonance imaging (MRI) protocols have been used to assess gastric emptying (GE) with MRI. This systematic review summarizes the current literature on the topic. The aim was to provide an overview of the available imaging protocols and underline the items that appear most agreed upon and those that deserve further investigation. METHODS: According to PRISMA guidelines, two independent reviewers conducted a systematic literature search with a pre-specified strategy in different databases. Peer-reviewed articles that utilized MRI techniques to assess GE in healthy volunteers (HVs) were included. The quality and the outcomes of the studies were reported and analyzed. KEY RESULTS: The literature search yielded 30 studies (531 HVs, weighted mean age 27.4, weighted mean body mass index 23.0 kg/m2 ), T2-weighted sequences, balanced turbo field echo, and balanced gradient echo were evenly utilized, with volunteers in the supine position (74% of the studies). After overnight fasting, both liquid (56%) and mixed (44%) meals were equally utilized. Segmentation of the volumes was predominantly performed manually (63%) with a reported mean T50 ranging from 7 to 330 min. CONCLUSIONS & INFERENCES: As observed in this systematic review, MRI is a flexible tool for assessing GE. Different protocols were analyzed, showing an equal capacity to assess the GE. However, many items in these protocols still require further investigation to obtain a common standard and increase this assessment quality.

Tapentadol and oxycodone reduce cingulate glutamate in healthy volunteers.

Tapentadol and oxycodone are commonly used analgesics. Preclinical studies have shown that oxycodone modulates brain metabolites related to opioid pathways, whereas tapentadol also affects noradrenergic activity. However, knowledge about the function of the medications in the human brain is limited. The aim was to investigate effects of tapentadol and oxycodone on brain glutamate, the most important neurotransmitter in pain processing. Magnetic resonance spectroscopy was obtained in 21 healthy subjects from the anterior cingulate cortex, prefrontal cortex, and insula at baseline and after 14 days of treatment with either 50 mg tapentadol, 10 mg oxycodone (equipotent dose, both extended release) or placebo twice daily in a randomized double-blind cross-over study. Compared to baseline, decreased glutamate/creatine levels were identified in anterior cingulate cortex after tapentadol (1.26 ± 0.14 vs. 1.35 ± 0.18, P = .04) and oxycodone (1.26 ± 0.10 vs. 1.35 ± 0.12, P = .05) treatments, both with 7% reduction. This indicates that both analgesics modulate the glutamatergic system at the supraspinal level in humans.

Importance of blinding and expectations in opioid-induced constipation: evidence from a randomized controlled trial.

OBJECTIVES: Previous studies have found little association between objective measures and the subjective experience of opioid-induced constipation. The subjective experience of opioid-induced constipation may be influenced by treatment expectations. While most trials control for treatment expectations through blinding, success rate is generally low. This study aimed to explore the association between objective measures and the subjective experience of opioid-induced constipation, while considering blinding success and treatment expectations, and other psychological factors. METHODS: Data from a randomized, double-blinded, placebo-controlled crossover trial including 21 healthy male participants was analyzed. Participants received either placebo, tapentadol, or oxycodone (in equipotent doses) for 14 days. They were assessed on objective and subjective measures of opioid-induced constipation (gastrointestinal transit time and the Patient Assessment of Constipation-Symptoms questionnaire, respectively), treatment guesses to indicate blinding success, and psychological factors. RESULTS: There was a strong association between objective and subjective measures of opioid-induced constipation when participants were treated with oxycodone (r=0.676, p=0.006). Furthermore, participants were able to guess that they received active treatment when treated with oxycodone (p<0.001), suggesting that treatment expectations may have influenced the subjective experience of symptoms. Finally, patterns of moderate associations between opioid-induced constipation and other psychological factors emerged, although none reached significance (p>0.05). CONCLUSIONS: Results indicate that treatment expectations could play an important role in the subjective experience of opioid-induced constipation, and support the importance of assessing blinding success in study trials. Besides expectations, other psychological factors may be associated with opioid-induced constipation.

Contractility patterns and gastrointestinal movements monitored by a combined magnetic tracking and motility testing unit.

BACKGROUND: Ingestible wireless capsules, including the 3D-transit magnetic capsule and the wireless motility capsule (WMC), describe gastrointestinal (GI) motility from changes in position or pressure. This study aimed to combine information on contractile events in terms of position (assessed with the 3D-transit) and change in pressure (assessed with the WMC) throughout the entire GI tract. METHODS: The 3D-transit capsule and WMC were combined into a single-wireless unit system. Three-dimensional space-time coordinates, pressure, and pH data from a pilot case were analyzed as the combined unit passed the GI tract. Two single and three continuous contraction patterns were defined according to pressure changes and quantified through the GI tract. KEY RESULTS: The combined unit was well tolerated and provided information on contractions throughout the gut. Single contraction patterns with no significant progressive movement of the unit were most prevalent in the stomach and the rectosigmoid colon. During the continuous contraction patterns, the unit moved in an antegrade or retrograde direction. Longer distance and higher velocity were seen during antegrade than during retrograde movements. The motility indices (as measured with WMC) in combined ascending, transverse and descending colon showed a positive linear association (r = 0.7) to the capsule movements (as measured with 3D-transit). CONCLUSIONS & INFERENCES: The combined system provides synchronous information about movements and gut contractions. These measurements can be used to extract more information from existing recordings and may enhance our understanding of GI motility in health and disease.

The effects of tapentadol and oxycodone on central processing of tonic pain.

OBJECTIVE: The present study investigated differences between opioids to experimental tonic pain in healthy men. METHODS: Twenty-one males participated in this cross-over-trial. Interventions twice daily were oxycodone (10 mg), tapentadol (50 mg) and placebo for 14 days. Tonic pain was induced on day 1, 4 and 14 by immersing the hand in 2 °C water for 120 s. Electroencephalography was recorded during test pain at baseline and after 14 days. Spectral analysis and source localization were investigated in predefined frequency bands. RESULTS: A decreased perception of pain on day 4 persisted throughout the 14 days compared to baseline (p < 0.006). Oxycodone decreased the electroencephalography spectral power in the delta and theta bands and increased power in the alpha1, alpha2 and beta1 bands (p < 0.03). Tapentadol increased spectral power in the alpha1 band (p < 0.001). Source localization revealed that oxycodone decreased activity of the temporal and limbic region in the delta band, and frontal lobe in the alpha2 and beta1 bands, whereas tapentadol decreased alpha1 band activity in the temporal lobe compared to placebo. CONCLUSION: Oxycodone and tapentadol reduced pain perception and changed the central processing of tonic pain. SIGNIFICANCE: Different mechanisms of action were involved, where oxycodone affected cortical structures more than tapentadol.

Regional Gastrointestinal Motility in Healthy Children.

OBJECTIVE: The aim of the study was to evaluate the safety and use of the 3D-Transit system (Motilis SA, Lausanne, Switzerland) and to describe regional gastrointestinal transit times, segmental colonic transit times, and colonic movement patterns in healthy children. METHODS: Twenty-one healthy children (11 girls, median age 10.5 years, range 7-15 years) were included. For evaluation of gastrointestinal transit times and colonic movement patterns, we used the minimally invasive electromagnetic 3D-Transit system. A small electromagnetic capsule (21.5 mm × 8.3 mm) was ingested and tracked through the gastrointestinal tract by a body-worn detector. Regional gastrointestinal transit times were assessed as time between capsule passage of anatomical landmarks. Colonic movement patterns were described and classified based on capsule movement velocity, direction, and distance. RESULTS: One child could not swallow the capsule and 20 children completed the study without any discomfort or side-effects. Median whole gut transit time was 33.6 (range 10.7-80.5) hours, median gastric emptying time was 1.9 (range 0.1-22.1) hours, median small intestinal transit time was 4.9 (range 1.1-15.1) hours, and median colonic transit time was 26.4 (range 6.8-74.5) hours. Median ascending colon/cecum transit time was 9.7 (range 0.3-48.1) hours, median transverse colon transit time was 5.6 (range 0.0-11.6) hours, median descending colon transit time was 2.6 (range 0.01-22.3) hours, and median sigmoid colon/rectum transit time was 7.5 (range 0.1-31.6) hours. Colonic movement patterns among children corresponded to those previously described in healthy adults. CONCLUSIONS: The 3D-Transit system is a well-tolerated and minimally invasive method for assessment of gastrointestinal motility in children.

Tapentadol results in less deterioration of gastrointestinal function and symptoms than standard opioid therapy in healthy male volunteers.

BACKGROUND: Tapentadol is a combined opioid agonist and norepinephrine reuptake inhibitor with fewer gastrointestinal side effects at equianalgesic doses compared with classical strong opioids. Previous studies on tapentadol have included multi-morbid patients in whom confounders exclude detailed assessment of the mechanistic effects and strict comparison with other opioids or placebo. This study aimed at investigating the effects of tapentadol and oxycodone on gastrointestinal motility and gastrointestinal side effects. METHODS: 21 healthy males participated in a randomized, double-blind, placebo-controlled, crossover study. Tapentadol (50 mg twice daily), oxycodone (10 mg twice daily), or placebo tablets were administered for 14 days. Segmental gastrointestinal transit times and colonic motility parameters were measured with electromagnetic capsules. Gastrointestinal side effects were assessed using questionnaires. KEY RESULTS: During dosing with tapentadol, gastrointestinal side effects and motility parameters were on placebo level. Compared with tapentadol, oxycodone increased whole gut transit time by 17.9 hours (p = .015) and rectosigmoid transit time by 6.5 hours (p = .005). Compared with tapentadol, oxycodone also reduced long, fast antegrade colonic movements (p = .001). In comparison with placebo, oxycodone prolonged whole gut transit time by 31.6 hours, (p < .001). Moreover, less long, fast antegrade colonic movements (p = .002) were observed during oxycodone. For oxycodone only, slow colonic movements were associated with gastrointestinal side effects. CONCLUSIONS & INFERENCES: In this mechanistic study, tapentadol caused significantly less colonic dysmotility and gastrointestinal side effects as compared with oxycodone in equianalgesic doses.

Colorectal dimensions in the general population: impact of age and gender.

PURPOSE: Constipation is among the most common gastrointestinal disorders, although, there is no generally accepted objective diagnostic criteria thereof. It has been proposed that colorectal dimensions assessed with Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) may support the diagnosis, but normative data are lacking. The aim of this study was to describe colorectal dimensions in a sample of the general population and to investigate whether the dimensions were under influence by age and gender. METHODS: The maximum diameters and cross-sectional areas of the ascending colon, descending colon and rectum were determined from 119 CT scans of trauma patients (age groups from 15 to 70 years, 84 men and 35 women). A regression model was applied to explore the impact of age and gender on colorectal dimensions. RESULTS: Overall, great variations were found for all colorectal diameters and cross-sectional areas (median diameter (5% percentiles; 95% percentiles): ascending 46 (26; 63) mm; descending 29 (16; 48) mm; rectum 39 (22; 67) mm. Women had larger rectal cross-sectional areas, reflecting more rectal content, compared to men (p = 0.003). Age did not affect colorectal diameters or cross-sectional areas (all p > 0.10). CONCLUSION: Great variations of colorectal dimensions were found. Larger rectal cross-sectional areas in women could likely reflect the fact that women have increased prevalence of constipation. Future studies should take gender into consideration when evaluating colorectal dimensions.

Modeling and measurement of the mechano-physiological function of the gastrointestinal organs.

OBJECTIVE: Gastroenterological research has traditionally been based on experimental approaches rather than mathematical modeling. However, the various patterns of the gastrointestinal (GI) tract functions are generated by the integrated functions of multiple tissues and cell types. Hence, a thorough study of the gut requires an understanding of the interactions between cells, tissues and GI organs in both healthy and diseased conditions. APPROACH: A unique way of coping with the resulting explosion in complexity is mathematical modeling. Novel modeling analysis together with the development of medical imaging techniques and advanced medical devices can be integrated into different protocols, to aid understanding of the physiology of GI diseases and clinical decision-making in GI cases. MAIN RESULTS: This review summarizes the current advanced mechano-physiological modeling analyses of the human GI organs, including imaging modeling analysis of mass transit processing and mechano-physiological modeling during organ distension. SIGNIFICANCE: The proposed models have the potential to shed some light on the functional understanding of the physiology and pathophysiology of both healthy and diseased guts.

Although tapentadol and oxycodone both increase colonic volume, tapentadol treatment resulted in softer stools and less constipation: a mechanistic study in healthy volunteers.

OBJECTIVES: Opioids are often used in treatment of severe pain, although many patients experience gastrointestinal side-effects like constipation. The aim of the current study was to investigate changes in colonic volume, as the result of both colonic motility and fluid transport, in healthy volunteers during opioid treatment with tapentadol as compared with oxycodone and placebo. METHODS: In a randomized, double-blind, cross-over study, 21 healthy male volunteers were administered equianalgesic dosages of oral tapentadol (50 mg bid), oxycodone (10 mg bid) or corresponding placebo for 14 days. Segmental colonic volumes were quantified using T2-weighted magnetic resonance images, and gastrointestinal side-effects were assessed with questionnaires. RESULTS: Total colonic volume increase during treatment was higher during tapentadol and oxycodone treatment (median 48 and 58 mL) compared to placebo (median -14 mL, both p≤0.003). Tapentadol (and placebo) treatment resulted in more bowel movements (both p<0.05) and softer stool consistency as compared with oxycodone (both p<0.01). Only oxycodone treatment was associated with increased constipation, straining during defecation, and tiredness (all p≤0.01). The colonic volume increase during treatment was directly associated with softer stools during tapentadol treatment (p=0.019). CONCLUSIONS: Tapentadol treatment increased colonic volume without leading to harder stools, likely as the opioid sparing effects result in less water absorption from the gut lumen. Oxycodone treatment also increased colonic volume, but with a simultaneous increase in stool dryness and gastrointestinal and central nervous system side-effects. The results confirm that tapentadol treatment may be advantageous to oxycodone regarding tolerability to pain treatment.