Genetic Variations in TrkB.T1 Isoform and Their Association with Somatic and Psychological Symptoms in Individuals with IBS

Irritable bowel syndrome (IBS), a disorder of gut-brain interaction, is often comorbid with somatic pain and psychological disorders. Dysregulated signaling of brain-derived neurotrophic factor (BDNF) and its receptor, tropomyosin-related kinase B (TrkB), has been implicated in somatic-psychological symptoms in individuals with IBS. Thus, we investigated the association of 10 single nucleotide polymorphisms (SNPs) in the regulatory 3' untranslated region (UTR) of NTRK2 (TrkB) kinase domain-deficient truncated isoform (TrkB.T1) and the BDNF Val66Met SNP with somatic and psychological symptoms and quality of life in a U.S. cohort (IBS n=464; healthy controls n=156). We found that the homozygous recessive genotype (G/G) of rs2013566 in individuals with IBS is associated with worsened somatic symptoms, including headache, back pain, joint pain, muscle pain, and somatization as well as diminished sleep quality, energy level and overall quality of life. Validation using U.K. BioBank (UKBB) data confirmed the association of rs2013566 with increased likelihood of headache. Several SNPs (rs1627784, rs1624327, rs1147198) showed significant associations with muscle pain in our U.S. cohort. Notably, these SNPs are predominantly located in H3K4Me1-enriched regions, suggesting their enhancer and/or transcription regulation potential. Together, our findings suggest that genetic variation within the 3'UTR region of the TrkB.T1 isoform may contribute to comorbid conditions in individuals with IBS, resulting in a spectrum of somatic and psychological symptoms that may influence their quality of life. These findings advance our understanding of the genetic interaction between BDNF/TrkB pathways and somatic-psychological symptoms in IBS, highlighting the importance of further exploring this interaction for potential clinical applications.

Stool and urine trefoil factor 3 levels: associations with symptoms, intestinal permeability, and microbial diversity in irritable bowel syndrome

Previously we showed that urine trefoil factor 3 (TFF3) levels were higher in females with irritable bowel syndrome (IBS) compared to non-IBS females. To assess if TFF3 is associated with symptoms and/or reflect alterations in gastrointestinal permeability and gut microbiota in an IBS population, we correlated stool and urine TFF3 levels with IBS symptoms, intestinal permeability, stool microbial diversity and relative abundance of predominant bacterial families and genera. We also tested the relationship of stool TFF3 to urine TFF3, and compared results based on hormone contraception use. Samples were obtained from 93 females meeting Rome III IBS criteria and completing 4-week symptom diaries. TFF3 levels were measured by ELISA. Permeability was assessed with the urine lactulose/mannitol (L/M) ratio. Stool microbiota was assessed using 16S rRNA. Stool TFF3, but not urine TFF3, was associated positively with diarrhoea and loose stool consistency. Higher stool TFF3 was also associated with lower L/M ratio and microbial diversity. Of the 20 most abundant bacterial families Mogibacteriaceae and Christensenellaceae were inversely related to stool TFF3, with only Christensenellaceae remaining significant after multiple comparison adjustment. There were no significant relationships between stool or urine TFF3 levels and other symptoms, nor between stool and urine levels. In premenopausal females, urine TFF3 levels were higher in those reporting hormone contraception. Collectively these results suggest that higher stool TFF3 levels are associated with IBS symptoms (loose/diarrhoeal stools), lower gut permeability, and altered stool bacteria composition (decreased diversity and decreased Christensenellaceae), which further suggests that TFF3 may be an important marker of host-bacteria interaction.

Sleep disturbances in irritable bowel syndrome: a systematic review

BACKGROUND

Sleep disturbances are well-documented among persons with irritable bowel syndrome (IBS). Difficulty in falling asleep, shorter sleep time, frequent arousal and awakenings, or non-restorative sleep are the most common manifestations. Sleep disturbances are also related to a higher risk of having IBS. Some researchers have provided evidence of a positive association between poorer subjective sleep quality and increased severity and frequency in gastrointestinal (GI) symptoms in those with IBS. However, findings from studies using objective sleep and activity measures, such as polysomnography and actigraphy, are inconclusive.

PURPOSE

This systematic review of the literature between 1990 and 2015 evaluates the evidence of sleep disturbances in adults with IBS and their relationship with GI symptoms.

The feasibility, usability, and clinical utility of traditional paper food and symptom journals for patients with irritable bowel syndrome

BACKGROUND

Paper food and gastrointestinal (GI) symptom journals are used to help irritable bowel syndrome (IBS) patients determine potential trigger foods. The primary aim of this study was to evaluate the feasibility, usability, and clinical utility of such journals as a data collection tool. A secondary aim was to explore a method for analyzing journal data to describe patterns of diet and symptoms.

METHODS

Participants (N=17) were asked to log three sets of 3-day food and symptom journals over a 15-day period. Feasibility was evaluated by journal completion rates, symptom logging compliance, and logging fatigability. The feasibility, usability, and clinical utility of journaling were also assessed by a customized evaluation and exit interview. For each journal, regression analyses were conducted to examine relationships between key meal nutrients and subsequent symptoms.

KEY RESULTS

Most participants were young (mean age 35±12) Caucasian (N=13) women (N=14). Journal completion rates were 100% for all participants with no logging fatigability. Over half perceived paper journaling of food and symptoms as feasible, usable, and clinically useful. Thirteen participants demonstrated a strong association with at least one symptom and meal nutrient. Patterns of associations differed among participants.

CONCLUSIONS AND INFERENCES

Paper journaling of food and GI symptoms for 9 days over a 15-day period appeared to be a feasible and usable data collection tool for IBS patients. Over half perceived journaling as at least somewhat clinically useful. Findings from this study support the anecdote that food trigger(s) and associated symptom(s) vary for each individual.

Heart rate variability is related to pain severity and predominant bowel pattern in women with irritable bowel syndrome

This study examined heart rate variability (HRV) in women with irritable bowel syndrome (IBS) to determine its association with gut pain and predominant bowel pattern. Women with IBS (constipation predominant n = 45, diarrhoea predominant n = 64, alternating n = 56) and healthy controls (n = 50) were recruited from the community. Severity of gut pain was measured retrospectively. The HRV (24 h) was summarized as high-frequency (HF) power and the ratio of low-frequency (LF) power to HF power. Among those women with IBS who have severe gut pain, the 15 constipation-predominant women had lower (P = 0.01) HF power and higher (P = 0.003) LF/HF ratio (geometric means 70 and 7.5, respectively) than the 21 women with diarrhoea-predominant IBS (286 and 3.1) and controls (224 and 3.9). In contrast, among women without severe pain, there is a smaller and not quite significant difference in the opposite direction. Using a broader definition of pain severity based on several questions nearly doubles the number of subjects in the severe pain group and shows even more significant results. The relationship of predominant bowel pattern to HRV is qualitatively different in the subgroup of patients with more severe pain than in the subgroup with less severe pain.

Does a physically active lifestyle improve symptoms in women with irritable bowel syndrome?

It has been proposed that physical activity moderates physiological or psychological responses to chronic conditions. The purpose of this study was to determine if women with a chronic functional gastrointestinal (GI) disorder, irritable bowel syndrome, had less active lifestyles than healthy controls and to test whether active women with irritable bowel syndrome had less severe recalled or daily reports of GI, psychological, and somatic symptoms than inactive women with irritable bowel syndrome. Questionnaires were used to measure GI and psychological distress and somatic symptoms in 89 women who participated in this study. A daily symptom and activity diary was kept for one menstrual cycle. Women with irritable bowel syndrome were significantly less likely to be active (48%) than control women (71%) (X2 = 3.4, p = .05). Within the irritable bowel syndrome group, active women were less likely to report a feeling of incomplete evacuation following a bowel movement than inactive women (p < .04), yet active women did not have less severe recalled psychological or somatic symptoms than inactive women. Active women with irritable bowel syndrome reported less severe daily somatic symptoms, which were accounted for by a lower level of fatigue (p = .003), but not daily GI or psychological symptoms. These results suggest that physical activity may produce select symptom improvement in women with irritable bowel syndrome.

Circadian rhythmicity of cortisol and body temperature: morningness-eveningness effects

The purpose of this study was to describe and compare the circadian rhythm of body temperature and cortisol, as well as self-reported clock times of sleep onset and offset on weekdays and weekends in 19 healthy adult "larks" (morning chronotypes) and "owls" (evening chronotypes), defined by the Home and Ostberg questionnaire. Day-active subjects entered the General Clinical Research Center, where blood was sampled every 2 h over 38 h for later analysis for cortisol concentration by enzyme immunoassay. Rectal body temperature was measured continuously. Lights were turned off at 22:30 for sleep and turned on at 06:00, when subjects were awakened. The acrophases (peak times) of the cortisol and temperature rhythms occurred 55 minutes (P < or = .05) and 68 minutes (P < .01), respectively, earlier in the morningness group. The amplitude of the cortisol rhythm was lower in the eveningness than in the morningness group (P = n.s.). Subject groups differed on all indices of habitual and preferred timing of sleep and work weekdays and weekends (P = .05-.001).

Gender differences and hormonal modulation in visceral pain

Women seek healthcare and are diagnosed more frequently with chronic somatic and visceral pain conditions relative to men. These conditions tend not to be life-threatening disorders, but rather ones that decrease people's quality of life, impinge on work and recreational activities, and increase healthcare resource utilization. With increased awareness of basic gender differences in biology and responsiveness to therapies, there has been renewed interest in factors which may account for the gender disparity in chronic visceral pain conditions. Basic and clinical evidence primarily from patients with irritable bowel syndrome has provided initial insights into visceral pain sensitivity, perception, and responsitivity.

Magnetic field goniometry: a new method to measure the frequency of stomach contractions

A system of magnetic field goniometry was developed for measuring the frequency of stomach contractions. This technique uses a handheld, electronic compass to measure the angular change in direction of a magnetic field generated by a small, ingested magnet. Measurements of gastric mechanical activity made by goniometry were validated with simultaneous measurements using manometry and electrogastrography. The agreement between these different modalities was excellent. In this pilot study, magnetic field goniometry provided an easy, minimally invasive, and accurate method to measure the frequency of gastric contractions.

Modifying perfusion, nutrition, and stress to promote wound healing in patients with acute wounds

Tissue injury is common among patients in acute care settings. The subsequent response to injury, wound healing, follows an intricate but well-defined sequence that, under normal conditions, proceeds to satisfactory repair. However, because of the complexity of the healing response, several factors can intervene to impair normal healing. As a better understanding of how diverse factors influence healing is gained, the use of interventions that modulate these factors becomes possible and potentially beneficial. This article reviews knowledge of perfusion, nutrition, and stress as they relate to healing in patients experiencing acute wounds. Therapeutic implications based on current research are discussed.

Feeding strategies for premature infants: randomized trial of gastrointestinal priming and tube-feeding method

BACKGROUND

Data on enteral feeding management of premature infants are limited and often not the subject of randomized clinical trials. Several small studies suggest benefits from the early initiation of feeding, but do not assess the combined effects of time of initiation of feeding, tube-feeding method, and type of milk used. Either singly or in combination, these treatments may affect growth, bone mineralization, biochemical measures of nutritional status, and feeding tolerance, and, ultimately, the duration of hospitalization.

METHODS

A total of 171 premature infants, stratified by gestational age (26 to 30 weeks) and diet (human milk or preterm formula) were assigned randomly among four treatment combinations in a balanced two-way design comparing the presence or absence of gastrointestinal (GI) priming for 10 days and continuous infusion versus intermittent bolus tube-feeding.

RESULTS

The major outcome, time required for infants to attain full oral feeding, was similar among treatments. GI priming was not associated with any measured adverse effect and was associated with better calcium and phosphorus retention, higher serum calcium and alkaline phosphatase activity, and shorter intestinal transit times. The bolus tube-feeding method was associated with significantly less feeding intolerance and greater rate of weight gain than the continuous method. In addition, the greater the quantity of human milk fed, the lower the morbidity.

CONCLUSIONS

Early GI priming with human milk, using the bolus tube-feeding method, may provide the best advantage for the premature infant.

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

Estrogen suppresses gastric motility response to thyrotropin-releasing hormone and stress in awake rats

Symptoms associated with gastric motility alteration vary with stress and ovarian hormone status, most notably in women with irritable bowel syndrome. This study examines combined effects, comparing gastric motility during administration of a stress-related neuropeptide thyrotropin-releasing hormone (TRH) and restraint stress in conscious rats of varied ovarian hormone status. Adult rats were ovariectomized and implanted with estrogen, progesterone, or vehicle-releasing pellets. After 21 days, intracerebroventricular (i.c.) cannula and gastric tension transducer were implanted. After 25-27 days, motility was recorded during neuropeptide injection (TRH/saline i.c.) or restraint stress. TRH induced increased motility in all groups; the response varied with hormone group, and was least and briefest in estrogen-treated rats. Motility during restraint varied with hormone group; it was diminished in estrogen-treated but not other groups. Ovarian hormone status (estrogen) modifies gut response to TRH and restraint stress.

Women with gastrointestinal symptoms: implications for nursing research and practice

Irritable bowel syndrome and functional bowel disorder are diagnoses used to describe chronic GI symptoms for which no overt pathological condition can be identified. Symptoms are more common in women and are frequently followed in gastroenterology clinics. The purpose of this article is to provide an overview of the research linking GI symptoms and reproductive cycling and to discuss implications for practice. GIGl symptoms such as stomach pain and nausea are highest during menses compared with other cycle phases; also, stool consistency is loosest at menses. This pattern is present in control subjects. In women with irritable bowel syndrome the same pattern is seen but with higher symptom intensity. Although animal studies have demonstrated that estrogen and progesterone modulate contractile function of some GI segments. In humans, symptoms are highest when these hormones are at the lowest levels. Thus, symptoms in women may be related to decreasing ovarian hormone levels or to other circulating hormones or factors which vary with the menstrual cycle. Additionally, other factors such as stress aggravate symptoms. Therapeutics directed toward increasing patient awareness of cyclic patterns in symptom complaints, for example, via the use of daily symptom diaries may be a useful adjunct to dietary, pharmacological, and other therapies.

Psychophysiological response to a laboratory challenge in women with and without diagnosed irritable bowel syndrome

The purpose of this study was to describe and compare physiological variables at baseline and in response to laboratory stress among women diagnosed with irritable bowel syndrome (IBS, n = 26), women with undiagnosed chronic gastrointestinal symptoms consistent with IBS (IBS-NP, n = 24), and asymptomatic women (n = 22). Urine catecholamine levels were measured in the first voided specimen on the morning of testing. Cardiovascular variables were measured at baseline and repeatedly during the Stroop Color-Word Conflict Test (Stroop). Women in the IBS group had higher baseline systolic blood pressure (SBP) than the control group and higher basal urine norepinephrine (NE) levels than the IBS-NP group. Control for activity or body mass reduced the group difference in SBP to nonsignificance but did not affect the observed difference in urine NE. There were no significant differences among the groups in other baseline values or in response to the Stroop. These results suggest that, despite higher basal urine catecholamine levels, cardiovascular reactivity to a cognitive challenge in a laboratory setting is not elevated in women with diagnosed IBS.

Sleep, psychological distress, and stress arousal in women with fibromyalgia

The purpose of this investigation was to compare self-reported sleep quality and psychological distress, as well as somnographic sleep and physiological stress arousal, in women recruited from the community with self-reported medically diagnosed fibromyalgia (FM) to women without somatic symptoms. Eleven midlife women with FM, when compared to 11 asymptomatic women, reported poorer sleep quality and higher SCL-90 psychological distress scores. Women with FM also had more early night transitional sleep (stage 1) (p < 0.01), more sleep stage changes (p < 0.03) and a higher sleep fragmentation index (p < 0.03), but did not differ in alpha-EEG-NREM activity (a marker believed to accompany FM). No physiological stress arousal differences were evident. Less stable sleep in the early night supports a postulate that nighttime hormone (e.g., growth hormone) disturbance is an etiologic factor but, contrary to several literature assertions, alpha-EEG-NREM activity sleep does not appear to be a specific marker of FM. Further study of mechanisms is needed to guide treatment options.

The relationship between daily life stress and gastrointestinal symptoms in women with irritable bowel syndrome

Research on irritable bowel syndrome (IBS), a functional disorder of the gastrointestinal (GI) system, has linked GI symptoms to stress. This study examined the relationship between daily stress and GI symptoms across women and within woman in IBS patients (n = 26), IBS nonpatients (IBS-NP; n = 23), and controls (n = 26), controlling for menstrual cycle phase. Women (ages 20-45) completed daily health diaries for two cycles in which they monitored daily GI symptoms and stress levels. The Life Event Survey (LES) was used as a retrospective measure of self-reported stress. The across-women analyses showed higher mean GI symptoms and stress in the IBS and IBS-NP groups relative to controls but no group differences in LES scores. The within-woman analyses found a significant and positive relationship between daily stress and daily symptoms in both the IBS-NP and the IBS groups. Controlling for menstrual cycle had no substantial impact on the results.

Gastric emptying and gastric-intestinal transit in rats with varying ovarian hormone status

Basal and stimulated gastric emptying and gastrointestinal (GI) transit in rats of varying ovarian hormone status were compared to define direct ovarian hormone effects on GI function. Thyrotropin-releasing hormone (TRH) was used to evoke vagal GI motility stimulation. Adult female Sprague-Dawley rats were anesthetized (equithesin), ovariectomized, and implanted with 28-day estrogen (E), progesterone, (P), E+P, or vehicle (V) pellets; males were also studied. On Day 26, fasted rats were anesthetized (urethane). Nonabsorbable 14C polyethylene glycol-4000 in saline was gavaged at t = 0. At t = 5 minutes, TRH or saline was administered intracisternally. At t = 30 or 60 minutes, the GI tract was removed, ligated, sectioned, and counted. Gastric emptying was expressed as 100% minus the ratio of gastric to total counts; GI transit was expressed as geometric center of radioactivity. In saline-treated rats, gastric emptying and GI transit at 60 minutes varied significantly among ovarian hormone-treated groups, with E lower and males elevated. TRH-significantly increased both variables at both times in all groups. Results are consistent with acceleration of upper GI function in the absence of E, possibly contributing to GI symptoms during menopause and late luteal phase.

Daily gastrointestinal symptoms in women with and without a diagnosis of IBS

This study compared daily gastrointestinal symptoms and stool characteristics across two menstrual cycles, and recalled bowel symptoms and psychological distress in women with irritable bowel syndrome (IBS, N = 22), IBS nonpatients (IBS-NP, N = 22), and controls (N = 25). Daily reports of abdominal pain, bloating, intestinal gas, constipation, and diarrhea did not differ significantly between the IBS and IBS-NP groups but both groups reported significantly higher symptoms than the control group. Stool consistencies was significantly looser in the IBS group relative to the control group. Menstrual cycle effects on symptoms were noted in all the groups. There were no significant differences in psychological distress between women with IBS and IBS-NP, but both groups reported significantly higher global distress than the control group. The lack of difference between the IBS and IBS-NP groups in contrast to the results of others, can be understood in terms of differences in recruitment strategies.

Symptoms and self-care strategies in women with and without dysmenorrhea

We compared the self-reports of women who reported either none-mild (N = 34) or moderate-extreme (N = 27) pain from uterine cramping regarding, (a) gastrointestinal, perimenstrual, and other symptoms during the 5 days before and after the beginning of menstrual flow; (b) smoking, alcohol use, exercise behaviors, and number of reported stressors; and (c) self-care strategies used for symptom management. Although there were significant differences between the two groups in reported symptoms, there were no significant between groups differences in smoking, alcohol use, exercise behaviors, and number of stressors reported. Despite the number of symptoms reported, relatively few self-care strategies were used. The most commonly reported strategy was the use of medication for cramping pain. The results confirm prior observations that dysmenorrhea is associated with a variety of symptoms and extend our understanding of how women manage these symptoms.

Gastric motility in rats with varying ovarian hormone status

Gastrointestinal (GI) symptoms suggestive of altered motility vary with menstrual cycle phase and menopause, but the effects of ovarian hormones on gastric motility have not been described. Basal and stimulated gastric motility were studied in male and female rats that were ovariectomized and implanted with continuous-release progesterone and/or estrogen pellets. Following 26 days of hormone treatment, rats were implanted with a gastric tension transducer. Contractile activity was recorded, then thyrotropin-releasing hormone (TRH) or saline was injected intracisternally and motility was monitored. An index was calculated based on frequency and amplitude; response to TRH was expressed as percentage of the basal index. Basal contraction frequency was highest in the estrogen and estrogen+progesterone groups. Hormone treatment significantly affected the TRH-stimulated motility index; TRH induced increased motility in all groups, with larger, more sustained responses in vehicle, progesterone, and male groups. Results demonstrate the ovarian hormone modulation of basal and stimulated gastric motility. Such modulation may contribute to changes in GI symptoms with altering ovarian hormone state.

Dietary fiber and distressing gastrointestinal symptoms in midlife women

In this descriptive study, 20 midlife women experiencing chronic distressing gastrointestinal (GI) symptoms recorded GI symptom severity in a symptom diary for a 30-day period and dietary intake in a 9-day food record. A wide variability in GI symptom severity was noted. Significant negative relationships were present between dietary fiber intake and abdominal pain, awakening with abdominal pain, nausea, awakening with nausea, and awakening with rectal pain. No significant relationships were noted between amount of caffeine or alcohol intake and distressing GI symptoms.

Comparison of diet composition in women with and without functional bowel disorder

Nurses are often involved in helping patients alleviate chronic distressing gastrointestinal symptoms such as those associated with irritable bowel syndrome or functional bowel disorder. One therapeutic strategy is to increase dietary fiber intake and to eliminate gastrointestinal (GI) irritants such as caffeine, alcohol, and tobacco smoking. However, little work has been done to establish a relationship between dietary factors and chronic GI symptoms. In this article, the authors: (a) describe and compare caloric and dietary constituent intake in symptomatic (n = 18) and asymptomatic (n = 37) women, and (b) examine the relationships among diet, GI symptoms, and stool characteristics in the two groups. In particular, total calories, fiber, fat, protein, and carbohydrates as well as alcohol and caffeine intakes were compared in women who do not smoke. Because menstrual cycle phase modulates both symptoms and appetite, women were studied during the follicular phase. Groups had similar caloric, fat, and protein intakes. Fiber intakes were similar and similar to national norms in both groups. When compared with asymptomatic women, the symptomatic women consumed more refined carbohydrates. Relationships were observed among dietary intake of refined carbohydrates, fiber, GI symptoms, and stool characteristics in women with functional bowel disorder.

Intestinal transit and body weight responses to ovarian hormones and dietary fiber in rats

A two-part experimental design was used to study the effects of ovarian hormone cessation, hormone supplementation, and dietary fiber composition on body weight, appetite, and intestinal transit. In Part 1, effects of ovarian hormone status on body weight and baseline and stimulated intestinal transit were measured in chow-fed rats. Sprague-Dawley rats were ovariectomized (OVX), then injected daily (22 days) with estrogen (E), progesterone (P), the combination (E + P), or placebo. Controls were sham operated and placebo injected. Among OVX rats, E and E + P had the least body weight gain (9%, 6%); placebo and P had the greatest (36%, 34%). In OVX-P, baseline intestinal transit (measured in anesthetized rats as distance traveled by a charcoal marker) was relatively low, but vagal stimulation via centrally administered thyrotropin-releasing hormone evoked an increase significantly larger than that in other groups. In Part 2, experiments probed the interacting effects of ovarian hormone cessation and dietary fiber composition on body weight and baseline intestinal transit. Caloric intake was measured to determine the contribution of altered appetite. Rats were OVX or sham operated, then fed liquid diets with or without dietary fiber (25 days). OVX fiber-fed rats had significantly higher caloric intake, weight gain, and baseline intestinal transit than other groups. Caloric intake did not fully account for group differences. These results demonstrate modulation of GI function by ovarian hormones and dietary fiber.

Women with gastrointestinal symptoms: implications for nursing research and practice

Irritable bowel syndrome and functional bowel disorder are diagnoses used to describe chronic GI symptoms for which no overt pathological condition can be identified. Symptoms are more common in women and are frequently followed in gastroenterology clinics. The purpose of this article is to provide an overview of the research linking GI symptoms and reproductive cycling and to discuss implications for practice. GI symptoms such as stomach pain and nausea are highest during menses compared with other cycle phases; also, stool consistency is loosest at menses. This pattern is present in control subjects. In women with irritable bowel syndrome the same pattern is seen but with higher symptom intensity. Although animal studies have demonstrated that estrogen and progesterone modulate contractile function of some GI segments, in humans, symptoms are highest when these hormones are at the lowest levels. Thus, symptoms in women may be related to decreasing ovarian hormone levels or to other circulating hormones or factors which vary with the menstrual cycle. Additionally, other factors such as stress aggravate symptoms. Therapeutics directed toward increasing patient awareness of cyclic patterns in symptom complaints, for example, via the use of daily symptom diaries may be a useful adjunct to dietary, pharmacological, and other therapies.

Mediation of thyrotropin-releasing hormone induced gastric motility increases in developing rats

Centrally administered thyrotropin-releasing hormone (TRH) induces vagally mediated gastrointestinal effects which may be cholinergic, serotonergic or a combination. This study investigated mediation of TRH-stimulated gastric motility in developing rats. A serotonin (5-HT) antagonist (5-HT2, ketanserin or xylamidine; 5-HT3, MDL 72222) or an acetylcholine receptor blocker (atropine) was administered intraperitoneally 30 min prior to intracisternal TRH (5-10 micrograms). The 5-HT-depleting para-chlorophenylalanine (p-CPA) was administered 48 or 72 h prior to TRH. Gastric motility, monitored via extraluminal strain gauge, was not increased with TRH in atropine-pretreated rats. MDL 72222 had a significant age-related effect on TRH-induced gastric motility increases while 5-HT2 antagonists and p-CPA treatment did not. Thus, acetylcholine receptor blockade inhibits TRH-stimulated gastric motility in young and adult rats while 5-HT3 antagonism eliminates the motility response in young (7 and 10 days) rats.

Systemic responses to different enteral feeding schedules in rats

The purpose of this study was to describe selected temporal systemic responses to different enteral feeding schedules using an animal model, as one prerequisite for determining optimal delivery times for human enteral feedings. The effect of feeding schedules and time of day were examined relative to body weight and plasma glucose, insulin, glucagon, and corticosterone levels. Adult male Sprague-Dawley rats (N = 80) were used in a 4 x 4 randomized block design. Rats started the feeding schedules on Day 11 post-gastrostomy tube placement. The following feeding schedules, often used by humans, were tested: 24-hour enteral; 24-hour oral; 12-hour (rest time) enteral; and 12-hour (rest time) oral. Plasma was collected on Day 20. Despite very different feeding schedules, there were no statistical differences in weight gain, or plasma glucose and glucagon levels. Levels of insulin and corticosterone were significantly influenced by time of day and/or feeding group. Temporal pattern disruption was greatest in the rest-time fed enteral group. Both route and timing of enteral delivery modified metabolic hormone patterns.

Pattern of gastrointestinal and somatic symptoms across the menstrual cycle

The pattern of gastrointestinal symptoms and select mood and somatic symptoms was examined across two menstrual cycles in women with (n = 19) and without (n = 39) functional bowel distress (FBD). The women (a) rated their gastrointestinal, perimenstrual, mood, and other symptoms and stool frequency and consistency daily; (b) completed the Menstrual Distress Questionnaire-T; and (c) had serum levels of estrogen and progesterone measured during the menses, follicular, and luteal phases. Stomach pain, nausea, and diarrhea were rated higher at menses in the group with FBD than in the group without FBD. Stomach pain was higher during the remaining days as well. The group with FBD reported higher levels of perimenstrual symptoms also on six of the eight Menstrual Distress Questionnaire-T subscales (P less than 0.01). Other complaints, e.g., poor work/school performance, were higher in women with FBD, but somatic symptoms that were expected to vary over the cycle did not differ between groups, except cramping pain. There were no significant group differences in ovarian hormone levels or stool consistency/frequency scores.

A possible 5-HT3 component of thyrotropin-releasing hormone-induced increases in gastric motility in developing rats

Intracisternal injection of thyrotropin-releasing hormone (TRH) increases gastric motility primarily via a vagal cholinergic mechanism. However, a serotonergic (5-HT) component may also exist. Rats (7, 10, 14, and > or = 50 days of age) were anesthetized and gastric motility monitored via an extraluminal strain gauge. Following baseline, ICS 205-930 which blocks 5-HT3 and 5-HT4 receptors (0.01, 0.10, or 1.0 mg/kg) was administered intraperitoneally, then 30 min later intracisternal TRH (5 or 10 micrograms). ICS 205-930 0.1 and 1.0 mg/kg blocked TRH-induced motility in 7-day-old rats. Results support a 5-HT3 or 5-HT4 receptor contribution to TRH-induced gastric motility stimulation, and suggest that receptor expression is dynamic during development.

Morningness-eveningness and early-morning salivary cortisol levels

The purposes of this exploratory study were: (1) to describe a 2-h segment of the early-morning salivary cortisol levels of morning (M) and evening (E) types of healthy, day-active adults on one morning; and (2) to compare selected demographic and sleep characteristics. The sample consisted of 20 subjects, aged 23-39 years, 10 of each type. Measures included: morningness-eveningness questionnaire score, demographic information, self-report sleep characteristics, and self-report of well-being. Beginning with time of arising, seven salivary samples were collected at approximately 20-min intervals. Among the sleep variables, bedtime (p = 0.005), time of mid-sleep (p = 0.002), and arising time (p = 0.043) were later in the E group as compared to the M group. Six M and one E subject awoke spontaneously on the morning of sampling without an awakening aid (p = 0.018). Even though total hours of sleep were comparable between groups, E subjects reported feeling less rested in the morning (p = 0.019). Although mean M group salivary cortisol levels were greater than mean E group levels for each sampling time, there were no significant group differences. Eight M subjects reached a sampling period salivary cortisol peak by 50 min after arising, contrasted with six E subjects who reached their peak at that time. These preliminary findings suggest that E types demonstrate lower morning arousal and a delay in their early-morning peak of salivary cortisol relative to M types. Further study is needed to explore the relationship between M and E types, their sleep-wake patterns, and cortisol secretion patterns.

Morphine inhibits TRH-induced gastric contractile activity

This study investigated the effect of centrally and peripherally administered thyrotropin releasing hormone (TRH) on gastric contractile activity of rats 14, 21, 28 and adult (greater than or equal to 50) days (D) of age, and the effect of morphine pretreatment on that response. Rats were anesthetized with urethane, then a tension transducer was implanted on the anterior gastric corpus. Following baseline recording, rats were pretreated with intraperitoneal morphine (2 mg/kg). TRH (5 micrograms) in saline or saline alone (0.6 microliters) was then injected into the cisternum magnum. Additionally, dose response to TRH was examined in 14- and 50-day-old rats. Intracisternal TRH induced a dose-related increase in gastric contractile activity in both 14- and 50-day-old rats. Higher doses of TRH (10 and 30 micrograms) prolonged the response as compared to low doses. Peripheral morphine pretreatment blocked the TRH-induced increase in gastric contractile activity in all age groups although a higher morphine dose (10 mg/kg) was needed to block the effect in 28D rats. Intravenous TRH (5, 10, 30 micrograms) produced an increase in gastric contractile activity in 14D rats which was blocked by vagotomy.

Menstrual cycle factors related to increased gastric contractile response to tube feeding

Evidence exists that the ovarian hormones have a modulating effect on gastrointestinal (GI) motility, yet details are sketchy and little attention has been paid to the effect that fluctuating hormone levels might have on women who are receiving enteral feedings. This study compared gastric motility indices in response to tube feedings at two points in the menstrual cycle, concurrently measured ovarian hormone levels, and described three potentially related factors (ie, GI symptoms, uterine cramping pain, reports of daily stressors). Intragastric motility responses to enteral feedings were obtained on 28 women (aged 19-37) during menses and midfollicular phases of two menstrual cycles. Intragastric pressure changes were monitored by an open-tipped cannula method at rest, during and after tube feeding (Ensure, 240 ml at 8 ml/min). Serum estradiol and progesterone levels were measured by radioimmunoassay. Women completed a daily diary of symptoms and stressors throughout the two menstrual cycles. Results showed that intragastric pressure amplitudes and frequencies were higher at menses compared with midfollicular recordings. At menses, prefeeding and feeding gastric pressure amplitudes were positively correlated with uterine cramping pain and GI symptoms (ie, nausea). At menses, postfeeding contraction frequencies were also correlated with uterine cramping pain. At midfollicular phase, progesterone levels correlated with gastric motility indices; number of stressors indirectly correlated with gastric motility indices. These data suggest that gastric responses to enteral feeding are influenced by menstrual cycle phase.

Morphine inhibits TRH-induced intestinal transit increases

The current study examined the effects of intraperitoneal (IP) and intracisternal (IC) administration of the opiate agonist, morphine, and an opioid, central beta-endorphin, on thyrotropin releasing hormone (TRH)-induced small intestinal transit increases. Anesthetized rats, 14-day and older, were studied to determine age-related differences. Results showed that in all age groups IP morphine (2 mg/kg) blocked TRH (15 micrograms)-induced increases in transit of a charcoal bolus. Morphine 1 microgram and beta-endorphin 1 microgram administered IC in 0.6 microliter failed to block TRH (10 microgram)-induced increases in intestinal transit in 14-day-old rats. However both morphine and beta-endorphin 1 micrograms IC blocked TRH-induced increases in adult rats. Dose-response studies demonstrated that higher doses (greater than 1 microgram) of morphine IC were required to block TRH-induced increases in preweaning rats.

Age-related variations in jejunum and distal colon contractile response to thyrotropin-releasing hormone in vitro

The effects of thyrotropin-releasing hormone (TRH) on the contractile activity of the proximal jejunum and distal colon of 3-, 7-, 14-, 21-, 28-, 50-day-old and adult male Sprague-Dawley rats were examined. Longitudinal segments were mounted in force displacement transducers and bathed in oxygenated, buffered Krebs' solution. In the proximal jejunum TRH 10(-6) M produced a tetrodotoxin (TTX)-sensitive tension increase in 3- to 14-day-old rats and a TTX-resistant biphasic response in older rats. TRH 10(-6) M produced a transient tension in the distal colon of rats less than or equal to 21 days old. Incubation with TRH 10(-6) M for 30 min increased responsiveness to acetylcholine 10(-7) M in approximately 50% of tissues studied. Direct and indirect effects of TRH are developmentally determined.

Nursing research opportunities in enteral nutrition

The concepts of individual adaptations, environmental, and person factors have been suggested as components of a framework for considering existing and potential investigations of enteral feeding as a therapeutic modality. Much of the work regarding adaptations to enteral feeding have described the pathophysiological and experimental responses of individuals--that there is less emphasis on the physiological and behavioral responses is evident in the literature. Also, little investigation has been focused on the environmental risk factors or the person vulnerability factors that are associated with less than optimal adaptations to enteral feeding. However, it is the understanding of all three of these aspects that will lead to comprehensive strategies for promoting satisfactory adaptations. To date, the majority of clinical therapeutic studies have focused on obviating or managing untoward reactions to enteral feeding by manipulating environmental physical factors. Certainly, more needs to be done, particularly with respect to temporal and rhythmicity considerations. However, there is an obvious lack of information about manipulating social circumstances or person factors (such as, knowledge deficit) for therapeutic ends. Examination of the multiple dimensions of patient responses to enteral nutrition modalities, the interaction of these various dimensions (concentrating on the social and person), and the physical elements is congruent with the holistic and caring nature of nursing practice and should guide future study.

Gastrointestinal symptoms and bowel patterns across the menstrual cycle in dysmenorrhea

Gastrointestinal (GI) functional indicators and symptoms across the menstrual cycle were examined in three groups of women: dysmenorrheic (n = 15), non-pill-taking nondysmenorrheic (n = 10), and nondysmenorrheic taking birth control pills (BCPs) (n = 9). Group assignment was based on the reported presence or absence of moderate to severe menstrual cramps in a GI Health Diary which subjects kept for two menstrual cycles. Stool consistencies and frequencies and GI symptoms were also recorded in this diary. Menstrual cycle phase significantly, p = .03, influenced stool consistencies for the sample as a whole with the loosest stools at menses. Reports of stomach pain were higher, p less than .001, at menses than at other cycle phases in all groups, and nausea, p less than .001, and decreased food intake, p less than .01, were more frequently reported by dysmenorrheic women at menses. More dysmenorrheic women had a history of menses-related GI symptoms. Both cycle phase and group differences were significant, p less than .05, for menstrual distress, with negative affect, pain, behavior changes, and autonomic reactions reported more frequently at menses by dysmenorrheic women.

Adrenalectomy and pentagastrin effects on gastrointestinal cholinergic enzyme activities

The present study examined the effects of pentagastrin and adrenalectomy on choline acetyltransferase (ChAT) and acetylcholine esterase (AChE), enzymes which synthesize and degrade acetylcholine in the rat gastrointestinal tract. Adrenalectomized and non-adrenalectomized rats, 14 and 21 days old, were treated with either pentagastrin (250 micrograms/kg i.p.) or saline for 7 days. Rats were sacrificed at 21 and 28 days of age. Adrenalectomy- and pentagastrin-treated 21-day-old rats had greater ChAT activities than those treated with pentagastrin alone, while AChE activities were higher in the pentagastrin-treated group. Adrenalectomy- and pentagastrin-treated 28-day-old rats had lower levels of activity as compared to pentagastrin-treated rats. The adrenal gland does appear to influence the response of cholinergic enzyme activities to pentagastrin.

Effects of corticosterone and metyrapone on gastrointestinal neurotransmitter enzyme activities

Adrenal glucocorticoids have been shown to produce alterations in the enzymes which synthesize and degrade cholinergic and catecholaminergic neurotransmitters in the central and peripheral nervous system. The present study examined the impact of altering plasma corticosterone levels via corticosterone or metyrapone ingestion, via the drinking water, on the developmental profile of choline acetyltransferase (ChAT), acetylcholine esterase (AChE), tyrosine hydroxylase (TH) and monoamine oxidase (MAO) in various gastrointestinal (GI) segments of rats. Three groups were studied: non-treated, corticosterone treated and metyrapone treated. Drug intake of pregnant (i.e., beginning on the 15th day of gestation), lactating and weaned rats was monitored until the male pups were sacrificed at 1, 3, 7, 14, 21, 35 and 50 days of age. Results showed that ChAT and TH activities peaked earlier in development in corticosterone treated rats as compared to non-treated and metyrapone treated rats. During the early postnatal period plasma corticosterone levels were inversely related to AChE and MAO activities in most GI segments. These results indicate that neurotransmitter enzyme activities in various GI segments are influenced by corticosterone during a critical period of development.

Pentagastrin on neurotransmitter enzyme activities in the rat gastrointestinal tract

The effects of three doses (5, 100, and 250 micrograms/kg) of pentagastrin on the activities of choline acetyltransferase (ChAT) and acetylcholine esterase (AChE), the neurotransmitter enzymes that synthesize and degrade acetylcholine, and monoamine oxidase (MAO), the degradation enzyme for catecholamines, were investigated. Enzyme activities were assayed in 6 gastrointestinal segments of 21- and 28-day-old and adult rats. All animals were injected intraperitoneally for 7 days with pentagastrin, and the results were compared with age-matched controls receiving saline for 7 days. Plasma and adrenal corticosterone levels were measured. No consistent differences in adrenocortical variables existed between pentagastrin- and saline-treated animals. Similarly, no consistent pentagastrin dose responses of ChAT, AChE, and MAO activities were evident. However, at the highest dose pentagastrin generally produced increases in ChAT activities in 21- and 28-day-old rats, while producing decreases in AChE and MAO activities in 21-day-old rats and increases in 28-day-old animals. There were few significant differences in enzyme activities in adult rats receiving pentagastrin as compared to saline.