Gastrointestinal motility in obesity

Understanding age-related changes: exploring the interplay of protein intake, physical activity and appetite in the ageing population

Globally, we are currently facing a rapid demographic shift leading to an increase in the proportion of older adults within the population. This raises concerns about the potential increase in age-related diseases and their impact on our ability to provide adequate health and end-of-life care. To apply appropriate interventions, understanding the changes that happen with ageing becomes essential. Ageing is often accompanied by a decrease in appetite and physical activity, which may lead to malnutrition, resulting in decreased muscle mass, physical capabilities and independence. To preserve muscle mass, older adults are advised to increase protein intake and physical activity. However, protein's high satiating effect may cause reduced energy intake. Physical activity is also advised to maintain or enhance older adult's appetite. This review paper aims to discuss appetite-related changes that occur with ageing and their consequences. In particular, it will focus on investigating the relationship between protein intake and physical activity and their impact on appetite and energy intake in the ageing population. Recent studies suggest that physical activity might contribute to maintaining or enhancing appetite in older adults. Nevertheless, establishing a definitive consensus on the satiating effect of protein in ageing remains a work in progress, despite some promising results in the existing literature.

Rapid Gastric emptying in spontaneously hypertensive rats

OBJECTIVE

To assess the rate of gastric emptying in spontaneously hypertensive rats (SHR) and to evaluate rapid gastric emptying as a possible predisposing factor for hypertension. Rapid gastric emptying of carbohydrates, known to elevate postprandial serum glucose, has been reported to occur in many insulin-resistant states, including hypertension. SHR exhibit insulin resistance similar to human hypertensive patients. No prior studies have assessed gastric emptying of an oral glucose solution in SHR as compared with control Wistar Kyoto rats (WKY).

METHODS

Using scintigraphic imaging, gastric emptying of a physiologic, orally consumed glucose solution was assessed in 12 SHR and 12 control WKY at 5 weeks of age, prior to the development of hypertension, and at 12 weeks of age after hypertension was fully established.

RESULTS

At 5 weeks, the gastric half-emptying time (GHET) was 67.8 ± 9.8 min for the SHR vs. 109.3 ± 18 ( P  = 0.042) minutes for the WKY controls. At 12 weeks, the GHET was 37.29 ± 10.3 min for the SHR vs. 138.53 ± 37.6 ( P  = 0.016) min for the WKY controls.

CONCLUSION

Gastric emptying was significantly more rapid in the SHR before and after the development of hypertension. Even though SHR are known to have increased sympathetic activity associated with their development of hypertension, this increased sympathetic activity does not inhibit gastric emptying. SHR are a promising animal model for investigating therapeutic agents for treating hypertension aimed at slowing the rate of gastric emptying.

Pharmacokinetics of obese adults: Not only an increase in weight

Obesity is a pathophysiological state defined by a body mass index > 30 kg/m2 and characterized by an adipose tissue accumulation leading to an important weight increased. Several pathologies named comorbidities such as cardiovascular disease, type 2 diabetes and cancer make obesity the fifth cause of death in the world. Physiological changes impact the four main phases of pharmacokinetics of some drugs and leads to an inappropriate drug-dose. For absorption, the gastrointestinal transit is accelerated, and the gastric empty time is shortened, that can reduce the solubilization and absorption of some oral drugs. The drug distribution is probably the most impacted by the obesity-related changes because the fat mass (FM) increases at the expense of the lean body weight (LBW), leading to an important increase of the volume of distribution for lipophilic drugs and a low or moderately increase of this parameter for hydrophilic drugs. This modification of the distribution may require drug-dose adjustments. By various mechanisms, the metabolism and elimination of drugs are impacted by obesity and should be considered as similar or lower than that non-obese patients. To better understand the necessary drug-dose adjustments in obese patients, a narrative review of the literature was conducted to highlight the main elements to consider in the therapeutic management of adult obese patients.

Production of highly branched α-limit dextrins with enhanced slow digestibility by various glycogen-branching enzymes

α-Limit dextrins (α-LDx) are slowly digestible carbohydrates that attenuate postprandial glycemic response and trigger the secretion of satiety-related hormones. In this study, more highly branched α-LDx were enzymatically synthesized to enhance the slowly digestible property by various origins of glycogen branching enzyme (GBE), which catalyzes the transglycosylation to form α-1,6 branching points after cleaving α-1,4 linkages. Results showed that the proportion of branched α-LDx in starch molecules increased around 2.2-8.1 % compared to α-LDx from starch without GBE treatment as the ratio of α-1,6 linkages increased after different types of GBE treatments. Furthermore, the enzymatic increment of branching points enhanced the slowly digestible properties of α-LDx at the mammalian α-glucosidase level by 17.3-28.5 %, although the rates of glucose generation were different depending on the source of GBE treatment. Thus, the highly branched α-LDx with a higher amount of α-1,6 linkages and a higher molecular weight can be applied as a functional ingredient to deliver glucose throughout the entire small intestine without a glycemic spike which has the potential to control metabolic diseases such as obesity and type 2 diabetes.

Association of Gastric Myoelectric Activity with Dietary Intakes, Substrate Utilization, and Energy Expenditure in Adults with Obesity

Obesity can modulate gastric myoelectric activity (GMA); however, the relationship of GMA with nutrient intakes and substrate utilization in adults with obesity is lacking. We examined the association of dietary intakes, energy expenditure, and substrate utilization with the GMA. Participants (n = 115, 18−60 y) were divided into healthy weight (HW, n = 24), overweight (OW, n = 29), obese (OB, n = 41) and morbidly obese (MO, n = 21). Two-day multi-pass 24 h recalls were conducted. The GMA was measured by multichannel electrogastrography (EGG) with water-load (WL) testing. Resting metabolic rate (RMR) and percentages of substrate utilization were measured by indirect calorimetry. In the HW, protein intake was directly correlated with average dominant frequency (ADF) and with WL volume, while in obese participants and the MO subgroup, WL volume correlated with carbohydrate intake. In participants with obesity, ADF was positively correlated with fiber intake. In participants with obesity and the OB subgroup, RMR was positively correlated with water-load volume (r = 0.39 and 0.37, p < 0.05). The ADF showed negative correlations with percent of fat utilization and positive correlations with percent of CHO utilization in non-obese groups. However, protein utilization showed inverse correlation in all obese groups. In conclusion, these distinctive associations suggest that certain dietary compositions and dieting regimens impact GMA patterns.

Measurement of intragastric pressure: an objective method to ascertain whether gastric wall extension is sufficient for assessment of the non-extension sign

Background and study aims  The optimal intragastric pressure (IP) for strong gastric wall extension is unclear. We aimed to develop an accurate method to measure IP using endoscopy and determine the pressure required for strong gastric wall extension. Methods  An in vitro experiment using an endoscope with a rubber attached at its tip was conducted. The process of inserting the pressure measurement probe into the forceps channel was skipped, and the tube of the pressure measurement device was directly connected to the forceps channel. In vivo, the pressure in 51 consecutive patients at the time of strong gastric wall extension was measured. Strong extension of the gastric wall was defined as when the folds in the greater curvature were flattened as a result of sufficient extension of the gastric wall by insufflated air during upper gastrointestinal endoscopy. The IP at that time was measured. Results  In vitr o , 20 mL of tap water was injected once into the forceps channel and then aspirated for 10 seconds. Pressure measurement after irrigation of the forceps channel as well as the measurement by inserting the probe procedure were accurately performed. In vivo, among the 51 included patients, the mean IP (range) was 14.7 mmHg (10-23). Strong extension of the gastric wall was obtained in 96.1 % of patients when the IP was 20 mmHg. Conclusions  We developed an accurate method to measure IP using upper gastrointestinal endoscopy. Strong extension of the gastric wall was obtained in almost all patients when the IP was 20 mmHg.

Copeptin, a surrogate marker of arginine8 vasopressin, has no ability to modulate human and mouse gastric motility

Copeptin, a glycosylated peptide fragment derived from the C-terminal region of the precursor of arginine⁸ vasopressin (AVP), is co-secreted with AVP in equimolar amounts. Elevated plasma AVP modulates gastric motility so we investigated whether copeptin had a similar effect. Copeptin (10^-9-10^-7M), and AVP (10^-12-10^-5M), were evaluated for their ability to modulate spontaneous and electrically-evoked (EFS) contractions of human proximal and distal gastric circular muscle in vitro. Similar experiments were performed on the mouse stomach and we re-examined the published effect of copeptin on the mouse aorta. In the presence of tetrodotoxin (10^-6M), atropine (10^-6M) and L-NAME (3 × 10^-4M), human proximal and distal stomach muscle contracted spontaneously and rhythmically as did mouse distal stomach. Copeptin (10^-9-10^-7M), had no effect on baseline muscle tone or myogenic spontaneous contractions of either human or mouse stomach. However, AVP concentration-dependently increased tone, amplitude and frequency of contractions in both regions of human stomach with similar potency (pEC₅₀ 9.0-9.5; n = 4) and threshold concentration (10^-11-10^-10M). AVP was similarly active in the mouse stomach. EFS-evoked cholinergic contractions (human and mouse) were unaffected by both peptides EFS-evoked relaxations of mouse stomach were unaffected by copeptin. In sub-maximally contracted mouse aorta the elevated tone was unaffected by copeptin (10^-7M) (cf. previously published study) but was reduced by carbachol (10^-6M) and sodium nitroprusside (10^-3M). We conclude that in contrast to AVP, copeptin over a concentration range reported in the plasma has no direct ability to modulate the motility of the human and mouse stomach.

Can adiponectin have an additional effect on the regulation of food intake by inducing gastric motor changes?

The regulation of food intake is a complex mechanism, and the hypothalamus is the main central structure implicated. In particular, the arcuate nucleus appears to be the most critical area in the integration of multiple peripheral signals. Among these signals, those originating from the white adipose tissue and the gastrointestinal tract are known to be involved in the regulation of food intake. The present paper focuses on adiponectin, an adipokine secreted by white adipose tissue, which is reported to have a role in the control of feeding by acting centrally. The recent observation that adiponectin is also able to influence gastric motility raises the question of whether this action represents an additional peripheral mechanism that concurs with the central effects of the hormone on food intake. This possibility, which represents an emerging aspect correlating the central and peripheral effects of adiponectin in the hunger-satiety cycle, is discussed in the present paper.

Association between Gastric Emptying Rate and Nutritional Status in Patients Treated with Continuous Ambulatory Peritoneal Dialysis

♦ Objective

To estimate gastric emptying rate in continuous ambulatory peritoneal dialysis (CAPD) patients, with or without indwelling dialysate, and to evaluate if there is an association between gastric motility and nutritional status.

♦ Design

Single-center cross-sectional study.

♦ Setting

Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Krakow, Poland.

♦ Patients and Methods

20 end-stage renal disease patients [11 F, 9 M; mean age 50.1 ± 11 years; treated with CAPD for median 13.5 (2 – 61) months] were studied. All patients were nondiabetic and had no comorbidity that might influence gastric motility; nor were they receiving any prokinetic drugs. Gastric emptying rate was estimated with dynamic abdominal scintigraphy, started immediately after complete ingestion of a standard 200-kcal solid meal injected with 99mTc-labeled colloid, activity 40 MBq. Scintigraphy was performed at the rate of 23 images in 4-minute intervals for 92 minutes. Two consecutive procedures — with and without PD fluid — were performed at weekly intervals. As nutritional parameters, protein catabolic rate (PCR) and lean body mass (LBM) (based on urea and creatinine kinetics, respectively), body mass index (BMI), and serum albumin were measured.

♦ Results

All analyzed gastric emptying parameters, measured with or without dialysis fluid, were markedly prolonged in patients compared to values accepted as normal in the local scintigraphy unit. Gastric emptying half-time (T1/2) and percent of initial activity in minute 46 and in minute 92 were 60.5 ± 25.0 minutes, 57.19% ± 17.5%, and 33.8% ± 20.9% with a full peritoneal cavity, and 63.9 ± 28.2 minutes, 59.1% ± 23.9%, and 33.9% ± 24.3% with an empty peritoneal cavity. The T1/2 and percent of initial activity after 46 and 92 minutes for healthy subjects were 39 ± 9 minutes, 45% ± 11%, and 15% ± 6%, respectively. T1/2 without dialysis fluid revealed a negative correlation with LBM and BMI values ( r = –0.5, p < 0.05, and r = –0.56, p < 0.01; respectively). Patients with dialysate-free T1/2 > 40 minutes were characterized by significantly lower serum albumin level compared to subjects with T1/2 < 40 minutes (39.2 ± 2.9 vs 42.9 ± 3.6 g/L, p < 0.05). The values of all gastric emptying parameters measured for an empty abdomen were prolonged in subjects with BMI < 25 kg/m2. No difference was found between patients with and without PD fluid.

♦ Conclusions

Gastric emptying is markedly impaired in CAPD patients compared to healthy subjects. However, the presence of dialysate does not influence it significantly. Gastric emptying rate was negatively associated with the nutritional status of treated subjects. This association can be demonstrated when gastric motility is measured with an empty peritoneal cavity.

Secretion of Gut Hormones and Expression of Sweet Taste Receptors and Glucose Transporters in a Rat Model of Obesity

OBJECTIVES

This study was undertaken to compare gut hormone secretion between high-fat-fed and control rats, and to examine the corresponding changes in the expression of sweet taste receptors and glucose transporters in the small intestine and hypothalamus.

METHODS

Four-week-old male Sprague Dawley rats were fed a standard or high-fat diet for 8 weeks (10 in each group), followed by an oral glucose tolerance test (50% glucose solution, 2 g/kg). Blood was sampled for glucose, insulin, glucagon-like peptide-1 (GLP-1) and polypeptide YY (PYY) assays. One week later, small intestinal and hypothalamic tissue were analyzed for sweet taste receptor and glucose transporter expression by real-time PCR.

RESULTS

After oral glucose, plasma GLP-1 concentrations were higher in high-fat-fed than standard-fat-fed rats (group × time interaction, p < 0.01) with significant differences at t = 15 min (p < 0.01) and 30 min (p < 0.05). Plasma PYY concentrations were lower in high-fat-fed than control rats at t = 0, 15 min (p < 0.05, respectively) and 120 min (p < 0.01). There were no differences in the expression of sweet taste receptors or glucose transporters between high-fat-fed and control rats in the duodenum, ileum, or hypothalamus.

CONCLUSIONS

Changes in GLP-1 and PYY secretion after a high-fat diet appear unrelated to any changes in the expression of sweet taste receptors or glucose transporters. Impaired PYY secretion with high-fat feeding suggests that PYY analogues may provide a potential therapy in the treatment of obesity.

Impact of gastric emptying and small intestinal transit on blood glucose, intestinal hormones, glucose absorption in the morbidly obese

This study evaluated gastric emptying (GE) and small intestinal (SI) transit in people with morbid obesity and their relationships to glycaemia, incretin hormones, and glucose absorption METHODS: GE and caecal arrival time (CAT) of a mixed meal were assessed in 22 morbidly obese (50.2 ± 2.5 years; 13 F:9 M; BMI: 48.6 ± 1.8 kg/m²) and 10 lean (38.6 ± 8.4 years; 5 F:5 M; BMI: 23.9 ± 0.7 kg/m²) subjects, using scintigraphy. Blood glucose, plasma 3-O-methylglucose, insulin, glucagon, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) were measured. Insulin sensitivity and resistance were also quantified RESULTS: When compared with lean subjects, GE (t50: 60.7 ± 6.5 vs. 41.1 ± 7.3 min; P  = 0.04) and CAT (221.5 ± 9.8 vs. 148.0 ± 7.1 min; P =  0.001) of solids were prolonged in morbid obesity. Postprandial rises in GIP (P = 0.001), insulin (P  = 0.02), glucose (P = 0.03) and 3-O-methylglucose (P = 0.001) were less. Whereas GLP-1 increased at 45 mins post-prandially in lean subjects, there was no increase in the obese (P  = 0.04). Both fasting (P = 0.045) and postprandial (P = 0.012) plasma glucagon concentrations were higher in the obese CONCLUSIONS: GE and SI transit are slower in the morbidly obese, and associated with reductions in postprandial glucose absorption, and glycaemic excursions, as well as plasma GIP and GLP-1.

Gastrointestinal Transit Time, Glucose Homeostasis and Metabolic Health: Modulation by Dietary Fibers

Gastrointestinal transit time may be an important determinant of glucose homeostasis and metabolic health through effects on nutrient absorption and microbial composition, among other mechanisms. Modulation of gastrointestinal transit may be one of the mechanisms underlying the beneficial health effects of dietary fibers. These effects include improved glucose homeostasis and a reduced risk of developing metabolic diseases such as obesity and type 2 diabetes mellitus. In this review, we first discuss the regulation of gastric emptying rate, small intestinal transit and colonic transit as well as their relation to glucose homeostasis and metabolic health. Subsequently, we briefly address the reported health effects of different dietary fibers and discuss to what extent the fiber-induced health benefits may be mediated through modulation of gastrointestinal transit.

Serum Leptin, Obestatin, and Ghrelin Levels and Gastric Emptying Rates of Liquid and Solid Meals in Non-obese Rats with Roux-en-Y Bypass Surgery or Prosthesis Placement: Implications for the Role of Vagal Afferents

BACKGROUND

The present study aimed to investigate the effects of Roux-en-Y gastric bypass (RYGB) and prosthesis placement on gastric emptying rate in conjunction with serum ghrelin-obestatin-leptin responses in non-obese rats with intact or denervated afferent innervation.

METHODS

Under anesthesia, male Sprague-Dawley rats underwent either sham operation, RYGB, prosthesis, and/or Gregory cannula placement. Three weeks later, liquid or solid gastric emptying tests were performed and serum ghrelin, leptin and obestatin levels were measured.

RESULTS

Both prosthesis placement and RYGB surgery delayed non-nutrient liquid emptying; while solid nutrient emptying was delayed only by RYGB. Nutrient-dependent (acid, hyperosmolal and peptone) delay in liquid emptying was abolished in rats with prosthesis. By vagal afferent denervation, delayed liquid emptying was abolished, while solid emptying was further delayed in rats with prosthesis. Ghrelin and obestatin levels were depressed in prosthesis-placed rats, but RYGB surgery had no impact on both levels. Leptin level was elevated in solid-food-given rats with prosthesis, but not changed in RYGB group, while it was reduced following liquid meal. All the changes observed in ghrelin, obestatin, or leptin levels in response to meal ingestion were reversed with vagal afferent denervation.

CONCLUSIONS

Both RYGB and prosthesis placement had delaying effects on gastric emptying rate of non-obese rats. Our results indicate that the short-term changes in gastric motility and hormone responses induced by volume reduction are reversed by afferent denervation, suggesting that sparing the vagal innervation could be essential for reaching optimum motility and hormone changes expected after bariatric surgery.

The role of alginates in regulation of food intake and glycemia: a gastroenterological perspective

Regulation of food intake through modulation of gastrointestinal responses to ingested foods is an ever-growing component of the therapeutic approaches targeting the obesity epidemic. Alginates, viscous and gel-forming soluble fibers isolated from the cell wall of brown seaweeds and some bacteria, are recently receiving considerable attention because of their potential role in satiation, satiety, and food intake regulation in the short term. Enhancement of gastric distension, delay of gastric emptying, and attenuation of postprandial glucose responses may constitute the basis of their physiological benefits. Offering physical, chemical, sensorial, and physiological advantages over other viscous and gel-forming fibers, alginates constitute promising functional food ingredients for the food industry. Therefore, the current review explores the role of alginates in food intake and glycemic regulation, their underlying modes of action and their potential in food applications.

Galanin and its receptors: a novel strategy for appetite control and obesity therapy

The rapid increase in the prevalence of overweight and obesity is becoming an important health problem. Overweight and obesity may cause several metabolic complications, including type 2 diabetes mellitus, hyperlipidemia, high cholesterol, coronary artery disease as well as hypertension. Prevention and treatment of obesity will benefit the treatment of these related diseases. Current strategies for treatment of obesity are not adequately effective and are frequently companied with many side effects. Thus, new ways to treat obesity are urgently needed. Galanin is undoubtedly involved in the regulation of food intake and body weight. The aim of this review is to provide up-to-date knowledge concerning the roles of central and peripheral galanin as well as its receptors in the regulation of metabolism, obesity and appetite. We also highlight the mechanisms of galanin and its receptors in experimental obesity, trying to establish a novel anti-obesity strategy.

Serotonin availability in rat colon is reduced during a Western diet model of obesity

Constipation and slowed transit are associated with diet-induced obesity, although the mechanisms by which this occurs are unclear. Enterochromaffin (EC) cells within the intestinal epithelium respond to mechanical stimulation with the release of serotonin [5-hydroxytryptamine (5-HT)], which promotes transit. Thus our aim was to characterize 5-HT availability in the rat colon of a physiologically relevant model of diet-induced obesity. EC cell numbers were determined immunohistochemically in chow-fed (CF) and Western diet-fed (WD) rats, while electrochemical methods were used to measure mechanically evoked (peak) and steady-state (SS) 5-HT levels. Fluoxetine was used to block the 5-HT reuptake transporter (SERT), and the levels of mRNA for tryptophan hydroxylase 1 and SERT were determined by quantitative PCR, and SERT protein was determined by Western blot. In WD rats, there was a significant decrease in the total number of EC cells per crypt (0.86 ± 0.06 and 0.71 ± 0.05 in CF and WD, respectively), which was supported by a reduction in the levels of 5-HT in WD rats (2.9 ± 1.0 and 10.5 ± 2.6 μM at SS and peak, respectively) compared with CF rats (7.3 ± 0.4 and 18.4 ± 3.4 μM at SS and peak, respectively). SERT-dependent uptake of 5-HT was unchanged, which was supported by a lack of change in SERT protein levels. In WD rats, there was no change in tryptophan hydroxylase 1 mRNA but an increase in SERT mRNA. In conclusion, our data show that foods typical of a WD are associated with decreased 5-HT availability in rat colon. Decreased 5-HT availability is driven primarily by a reduction in the numbers and/or 5-HT content of EC cells, which are likely to be associated with decreased intestinal motility in vivo.

Intragastric pressure during food intake: a physiological and minimally invasive method to assess gastric accommodation

BACKGROUND

The stomach relaxes upon food intake and thereby provides a reservoir while keeping the intragastric pressure (IGP) low. We set out to determine whether we could use IGP as a measurement for stomach accommodation during food intake.

METHODS

In fasted healthy volunteers (n = 7-17) a manometer and an infusion catheter were positioned in the proximal stomach. After a stabilization period a nutrient drink was intragastrically infused at 15, 30 and 60 mL min(-1). To investigate the effect of impaired accommodation the effect of N(G)-monomethyl-L-arginine (L-NMMA) was examined. The volunteers scored satiation until maximum, when the experiment ended. The IGP was presented as a change from baseline (mean ± SEM) and compared with repeated measures anova.

KEY RESULTS

Independent on the ingestion speed, the IGP decreased initially and gradually increased thereafter. Volunteers scored maximal satiation after 699 ± 62, 809 ± 90 and 997 ± 120 mL nutrient drink infused (15, 30 and 60 mL min(-1) respectively; P < 0.01). Maximum IGP decrease was 3.4 ± 0.5 mmHg after 205 ± 28 mL, 5.1 ± 0.7 mmHg after 212 ± 46 mL, and 5.2 ± 0.7 mmHg after 296 ± 28 mL infused volume [15, 30 and 60 mL min(-1) respectively; not significant (ns)]. Post hoc analysis showed significant correlations between IGP and satiation score increase. During L-NMMA infusion IGP was significantly increased while subjects drank significantly less (816 ± 91 vs 1032 ± 71 mL; P < 0.005). Interestingly, the correlation between IGP increase and satiation score increase did not differ after L-NMMA treatment.

CONCLUSIONS & INFERENCES

The IGP during nutrient drink ingestion provides a minimally invasive alternative to the barostat for the assessment of gastric accommodation. These findings furthermore indicate that IGP is a major determinant of satiation.

Review article: the role of gastric motility in the control of food intake

BACKGROUND

From a classical point of view, gastric motility acts to clear the stomach between meals, whereas postprandial motility acts to provide a reservoir for food, mixing and grinding the food and to assure a controlled flow of food to the intestines.

AIM

To summarise findings that support the role of gastric motility as a central mediator of hunger, satiation and satiety.

METHODS

A literature review using the search terms 'satiety', 'satiation' and 'food intake' was combined with specific terms corresponding to the sequence of events during and after food intake.

RESULTS

During food intake, when gastric emptying of especially solids is limited, gastric distension and gastric accommodation play an important function in the regulation of satiation. After food intake, when the stomach gradually empties, the role of gastric distension in the determination of appetite decreases and the focus will shift to gastric emptying and intestinal exposure of the nutrients. Finally, we have discussed the role of the empty stomach and the migrating motor complex in the regulation of hunger signals.

CONCLUSIONS

Our findings indicate that gastric motility is a key mediator of hunger, satiation and satiety. More specifically, gastric accommodation and gastric emptying play important roles in the regulation of gastric (dis)tension and intestinal exposure of nutrients and hence control satiation and satiety. Correlations between gastric accommodation, gastric emptying and body weight indicate that gastric motility can also play a role in the long-term regulation of body weight.

A Western diet increases serotonin availability in rat small intestine

Diet-induced obesity is associated with changes in gastrointestinal function and induction of a mild inflammatory state. Serotonin (5-HT) containing enterochromaffin (EC) cells within the intestine respond to nutrients and are altered by inflammation. Thus, our aim was to characterize the uptake and release of 5-HT from EC cells of the rat ileum in a physiologically relevant model of diet-induced obesity. In chow-fed (CF) and Western diet-fed (WD) rats electrochemical methods were used to measure compression evoked (peak) and steady state (SS) 5-HT levels with fluoxetine used to block the serotonin reuptake transporter (SERT). The levels of mRNA for tryptophan hydroxylase 1 (TPH1) and SERT were determined by quantitative PCR, while EC cell numbers were determined immunohistochemically. In WD rats, the levels of 5-HT were significantly increased (SS: 19.2 ± 3.7 μm; peak: 73.5 ± 14.1 μm) compared with CF rats (SS: 12.3 ± 1.8 μm; peak: 32.2 ± 7.2 μm), while SERT-dependent uptake of 5-HT was reduced (peak WD: 108% of control versus peak CF: 212% control). In WD rats, there was a significant increase in TPH1 mRNA, a decrease in SERT mRNA and protein, and an increase in EC cells. In conclusion, our data show that foods typical of a Western diet are associated with an increased 5-HT availability in the rat ileum. Increased 5-HT availability is driven by the up-regulation of 5-HT synthesis genes, decreased re-uptake of 5-HT, and increased numbers and/or 5-HT content of EC cells which are likely to cause altered intestinal motility and sensation in vivo.

Deficits in gastrointestinal responses controlling food intake and body weight

The gastrointestinal tract serves as a portal sensing incoming nutrients and relays mechanical and chemosensory signals of a meal to higher brain centers. Prolonged consumption of dietary fat causes adaptive changes within the alimentary, metabolic, and humoral systems that promote a more efficient process for energy metabolism from this rich source, leading to storage of energy in the form of adipose tissue. Furthermore, prolonged ingestion of dietary fats exerts profound effects on responses to signals involved in termination of a meal. This article reviews the effects of ingested fat on gastrointestinal motility, hormone release, and neuronal substrates. It focuses on changes in sensitivity to satiation signals resulting from chronic ingestion of high-fat diet, which may lead to disordered appetite and dysregulation of body weight.

Characteristics of autonomic nervous activity in obese people during mechanical gastric distension that mimics gastric filling

AIM: To investigate the characteristics of autonomic nervous activity in obese people during mechanical gastric distension and analyze the relationship between autonomic nervous function and gastric sensitivity.

METHODS: Sixty-seven obese subjects and thirty-two normal controls were studied using a barostat and an electrocardiograph. Before and during mechanical distension of the proximal stomach, myocardial electrical activity was recorded, and heart rate variability (HRV) analysis was performed.

RESULTS: At baseline, obese subjects had significantly higher total power (TP), ultra-low-frequency power (ULF), low-frequency power (LF) and high-frequency power (HF) in the HRV power spectrum than control ones (all P < 0.01 or 0.05). At initial satiety level, TP, ULF, LF and HF values declined compared with baseline values, and the changes in these values were significantly greater in obese subjects than in control ones (all P < 0.01). At maximal tolerated volume, TP and ULF values increased while LF and HF values decreased, and the changes in these values were significantly greater in obese subjects than in control ones (both P < 0.01).

CONCLUSION: Obese people have large gastric capacity, higher gastric compliance and accommodation, and delayed satiety compared to non-obese ones, which is closely associated with abnormal autonomic nervous function.

Proximal gastric function in volunteers with different types of simple obesity: an analysis of 67 cases

AIM: To analyze the characteristics of changes in proximal gastric function in volunteers with different types of simple obesity.

METHODS: Sixty-seven volunteers with simple obesity were divided into three groups, namely, group A (volunteers with binge eating), group B (volunteers with normal diet) and group C (volunteers with functional dyspepsia). Thirty-two non-obese healthy volunteers formed the control group (group D). Gastric barostat studies were then performed to record the changes in gastric capacity, intragastric pressure and gastric compliance in response to mechanical distension.

RESULTS: The initial volume (IV) and maximal tolerance volume (MV) in group A were significantly larger than those in group D (t = -6.63 and -5.20, respectively; both P < 0.01), whereas these two parameters in group C were significantly lower than those in group D (t = 3.48 and 2.11, respectively; both P < 0.01). The initial intragastric pressure (IP) and the maximal tolerance pressure (MP) in group C were significantly lower than those in group D (t = 2.09 and 2.08, respectively; both P < 0.05). The initial gastric compliance (IC) and the maximal tolerance compliance (MC) in group A were significantly higher than those in group D (t = 2.44 and -5.56, respectively; both P < 0.01), whereas these two parameters in group C were significantly than those in group D (t = 2.44 and 2.32, respectively; both P < 0.05).

CONCLUSION: The main reason for the development of obesity in binge eaters is due to an increase in gastric capacity, compliance and accommodation as well as a delay in satiety.

Gastroesophageal reflux disease in morbid obesity: the effect of Roux-en-Y gastric bypass

BACKGROUND

Gastroesophageal reflux disease (GERD) is a common condition in obesity. The impact of Roux-en-Y gastric bypass (RYGBP) on GERD is poorly known. We studied the effect of the RYGBP on GERD in patients with morbid obesity (MO).

METHODS

Twenty consecutive patients with MO (BMI > 40 kg/m(2)) were studied before and 6 months after RYGBP. GERD symptoms were evaluated with Carlsson-Dent questionnaire (CDQ). All the patients underwent esophageal manometry and ambulatory 24-h pH-metry. Chi-square test was used to compare categorical variables, and Wilcoxon test was used for numerical variables. A p value under 0.05 was considered significant.

RESULTS

There were 16 women (80%) and 4 men (20%) with mean age 38.9 +/- 6.9 years included in this study. BMI was 48.5 +/- 6.2 kg/m(2) and 33.2 +/- 4.5 kg/m(2) before and after RYGBP, respectively. Mean weight reduction was 42.5 +/- 9.7 kg (p < 0.001). Reflux symptoms measured by CDQ and esophageal acid exposure improved significantly after RYGBP. The percentage of time of pH < 4 was 10.7 +/- 6.7 before and 1.6 +/- 1.2 after the surgical procedure (p < 0.001). LES basal pressure before and after the RYGBP was 18 +/- 11 and 20.1 +/- 5.6 mmHg (p = 0.372), and the esophageal body amplitude was 104.2 +/- 47.2 and 75.1 +/- 36.2 mmHg, respectively (p = 0.005).

CONCLUSION

RYGBP improves GERD symptoms and reduces esophageal acid exposure in patients with MO.

Gastrointestinal regulation of food intake: general aspects and focus on anandamide and oleoylethanolamide

The gastrointestinal tract plays a pivotal role in the regulation of food intake and energy balance. Signals from the gastrointestinal tract generally function to limit ingestion in the interest of efficient digestion. These signals may be released into the bloodstream or may activate afferent neurones that carry information to the brain and its cognitive centres, which regulates food intake. The rate at which nutrients become systemically available is also influenced by gastrointestinal motility: a delay in gastric emptying may evoke a satiety effect. Recent evidence suggests that the endocannabinoid anandamide and the related acylethanolamide oleoylethanolamide are produced in the intestine and might regulate feeding behaviour by engaging sensory afferent neurones that converge information to specific areas of the brain. The intestinal levels of these acylethanolamides are inversely correlated to feeding, as food deprivation increases intestinal levels of anandamide (which acts in the gut as a 'hunger signal'), while it decreases the levels of oleoylethanolamide (which acts in the gut as a 'satiety signal'). Additionally, these acylethanolamides, whose gastric levels change in response to diet-induced obesity, alter gastrointestinal motility, which might contribute to their effect on food intake and nutrient absorption.

Inhibitory effect of the anorexic compound oleoylethanolamide on gastric emptying in control and overweight mice

Gastric emptying regulates food intake. Oleoylethanolamide (OEA), an endogenous acylethanolamide chemically related to the endocannabinoid anandamide, inhibits food intake, but its effect on gastric emptying is unknown. Here, we investigated the effect and the role of OEA on gastric emptying in mice fed either a standard (STD) or a high-fat diet (HFD) for 14 weeks. Gastric emptying was reduced by OEA, but not by its saturated analog, palmitoylethanolamide. The effect of OEA was unaffected by rimonabant (cannabinoid CB1 receptor antagonist), SR144528 (cannabinoid CB2 receptor antagonist), 5'-iodoresiniferatoxin (transient receptor potential vanilloid type 1 antagonist), or MK886 (peroxisome proliferator-activated receptor-alpha) antagonist. Compared to STD mice, HFD mice showed delayed gastric emptying and higher levels of gastric OEA. HFD-induced increase in OEA levels was accompanied by increased expression of the OEA-synthesizing enzyme N-acyl-phosphatidylethanolamine-selective phospholipase D and decreased expression of the OEA-degrading enzyme fatty acid amide hydrolase. These results might suggest that elevation of gastric OEA could possibly contribute to the delayed gastric emptying observed in HFD-fed animals. HFD regulates OEA levels in the stomach through an increase of its biosynthesis and a decrease of its enzymatic degradation. The inhibitory effect of OEA on gastric emptying here observed might underlie part of the anorexic effects of this compound previously reported.

Gastric Emptying of Water in Obese Pregnant Women at Term

BACKGROUND

Healthy nonpregnant and pregnant patients may ingest clear liquids until 2 h before induction of anesthesia without adversely affecting gastric volume. In this study, we compared gastric emptying in obese, term, nonlaboring pregnant women (prepregnancy body mass index >35 kg/m2) after the ingestion of 50 and 300 mL of water.

METHODS

Gastric emptying was assessed in 10 obese, term pregnant volunteers using both serial gastric ultrasound examinations and acetaminophen absorption in a crossover study design. After an overnight fast, volunteers ingested 1.5 g acetaminophen and 50 or 300 mL water (randomly assigned) on two occasions separated by at least 2 days. Serial gastric antrum cross-sectional areas were determined using gastric ultrasound imaging and the half-time to gastric emptying (T([1/2])) was calculated. Areas under the plasma acetaminophen concentration versus time curve (AUC), peak concentrations (C(max)), and time to peak concentration (t(max)) for 50 mL and 300 mL ingestions were compared.

RESULTS

Mean prepregnancy body mass index was 41 +/- 9 kg/m(2). Gastric emptying T([1/2]) was not different after ingestion of 300 mL water compared with 50 mL (23 +/- 11 min vs 32 +/- 15 min). There were no differences between acetaminophen AUCs at 60, 90, or 120 min, C(max) or t(max) after ingestion of 300 mL compared with 50 mL of water.

CONCLUSIONS

Gastric emptying in obese, nonlaboring term pregnant women is not delayed after ingestion of 300 mL compared with 50 mL of water. Gastric antral volume after ingestion of 300 mL of water is similar to the baseline fasting level at 60 min.

Gut-brain neuropeptides in the regulation of ingestive behaviors and obesity

The prevalence of obesity has increased to epidemic proportions and has become an urgent public health problem. Obesity causes significant morbidity and mortality and its impact on health-care costs in the United States is growing dramatically. Apart from bariatric surgery treatment, options are limited. Future advances in treatment will rely on a better understanding of the pathogenesis and physiology of obesity. Alterations in gastrointestinal (GI) sensory-motor function and symptoms have been associated with obesity. GI neuroendocrine communications between the periphery and the brain regulate energy balance and ingestive behaviors. These interactions are largely mediated by the gut-brain peptides through negative and positive feedback loops that maintain energy homeostasis. Bariatric surgery has been shown effective, but the mechanisms of weight loss following these procedures clearly require further studies and a better understanding of the affects of bariatric surgery on the gut-brain neuropeptide homeostasis. Gut-brain peptides may provide attractive therapeutic targets in the fight against this very morbid disease. We review alterations in GI function and some of the more important gut-brain neuropeptides that occur in obesity.

Gastric electrical activity and cardiovascular risk factors in relation to autonomic nervous function, hormonal responses, and health-related lifestyles in young men

BACKGROUND

Electrogastrography (EGG) is the noninvasive recording of gastric myoelectrical activity. The purpose of the present study was to assess associations of EGG with risk factors for cardiovascular disease (CVD), autonomic nervous function, hormonal responses, and health-related lifestyles.

METHODS

EGG was measured in 435 Japanese men, aged 24-39 years, who worked at the same company. In addition to anthropometric measurements and blood examinations, power spectral analysis of heart rate variability in low-frequency (LF; 0.04-0.15 Hz) and high-frequency (HF; 0.15-0.40 Hz) bands was conducted. LF/HF and HF were used as the indicators of sympathetic and parasympathetic nervous activity, respectively. Serum cortisol and catecholamine levels were measured as well.

RESULTS

In univariate analyses, the EGG frequency was associated positively with the serum high-density lipoprotein (HDL) and cholesterol level (both-P < 0.0001) and negatively with age, body mass index (BMI), serum triglyceride level, fasting blood sugar, and diastolic blood pressure (all P < 0.05). The EGG frequency tended to increase with increases in the HF band (P = 0.10) and was not significantly associated with the LF/HF ratio (P = 0.45). Neither hormonal responses nor health-related lifestyle factors such as smoking and alcohol were significant (all P > 0.05). A multivariate analysis indicated that both the HDL cholesterol level and BMI were independent predictors of EGG frequency (both P < 0.05), after adjusting for the significant effects of age, HF, and other CVD factors.

CONCLUSIONS

Slowed EGG frequency appeared to be linked with various CVD risk factors, including obesity and low HDL cholesterol levels, in young men.

Influences of fat restriction and lipase inhibition on gastric emptying in obesity

OBJECTIVE

Accelerated gastric emptying of solids may play a role in the pathogenesis of obesity. Orlistat, a potent lipase inhibitor, induces fat malabsorption and body weight loss but might accelerate gastric emptying as a result of suppressed CCK release. The aim was to investigate the role of fat restriction and lipase inhibition in CCK release and gastric emptying.

SUBJECTS

A total of 28 patients (three male (M)/25 female (F); mean (s.d.) BMI 37.4(3.9) kg/m2) entering a randomized, double-blind, placebo-controlled study.

MEASUREMENTS

CCK release and gastric emptying by scintigraphy at the start (T0), after 1 month of an energy- and fat-restricted diet and placebo (T1), and after 1 month (T2) and 1 year (T3) of randomization to placebo or 120 mg orlistat three times a day.

RESULTS

One month of dieting and a weight loss of 2.3 kg (2.1% of initial weight) did not affect gastric emptying of liquids and solids. Basal and meal-stimulated CCK levels remained unaltered. Placebo-treated subjects who continued the diet for 1 month demonstrated a borderline significant suppressed CCK secretion and a weight loss of 1.2 kg (1.0%) without an effect on gastric emptying. After 1 year, the CCK secretion recovered to or beyond values at the start. A significantly slower emptying of solids (17.6 (T3) versus 25.9 (T1)%/h) and a weight loss of 10.4 kg (9.9%) was observed. Subjects on 120 mg orlistat lost 2.5 kg (2.5%) after 1 month, and 9.8 kg (9.9%) after 1 year. Basal and postprandial CCK release decreased significantly after the first month of orlistat treatment but normalized after 1 year. Diet and lipase inhibition did not have any influence on gastric emptying.

CONCLUSION

Energy and fat restriction of 1 month did not alter gastric emptying in the whole group. Continuation of the diet for 1 year resulted in a delayed gastric emptying of solids. Lipase inhibition did not result in a sustained depressed CCK release and the anticipated acceleration of gastric emptying did not occur.

Visceral response to acute retrograde gastric electrical stimulation in healthy human

AIM: To investigate the visceral response to acute retrograde gastric electrical stimulation (RGES) in healthy humans and to derive optimal parameters for treatment of patients with obesity.

METHODS: RGES with a series of effective parameters were performed via a bipolar mucosal electrode implanted along the great curvature 5 cm above pylorus of stomach in 12 healthy human subjects. Symptoms associated with dyspepsia and other discomfort were observed and graded during RGES at different settings, including long pulse and pulse train. Gastric myoelectrical activity at baseline and during different settings of stimulation was recorded by a multi-channel electrogastrography.

RESULTS: The gastric slow wave was entrained in all the subjects at the pacing parameter of 9 cpm in frequency, 500 ms in pulse width, and 5 mA in amplitude. The frequently appeared symptoms during stimulation were satiety, bloating, discomfort, pain, sting, and nausea. The total symptom score for each subject significantly increased as the amplitude or pulse width was adjusted to a higher scale in both long pulse and pulse train. There was a wide diversity of visceral responses to RGES among individuals.

CONCLUSION: Acute RGES can result in a series of symptoms associated with dyspepsia, which is beneficial to the treatment of obesity. Optimal parameter should be determined according to the individual sensitivity to electrical stimulation.

Ghrelin, peptide YY, glucose-dependent insulinotropic polypeptide, and hunger responses to a mixed meal in anorexic, obese, and control female adolescents

To determine whether peptide YY (PYY), ghrelin, glucose-dependent insulinotropic polypeptide (GIP), and satiety responses to food intake are impaired in anorexia or obesity, we studied 30 female adolescents with anorexia nervosa [body mass index (BMI) 16.3 kg/m2], obesity (BMI 34.3 kg/m2), or normal weight (BMI 20.2 kg/m2). PYY, ghrelin, GIP, insulin, and glucose concentrations and four markers of satiety were measured for 240 min after a mixed meal. The area under the curve for glucose was similar in obese (OB) and normal-weight control (C) subjects but was 15% lower in anorexic (AN) subjects. The area under the curve for insulin was 47% lower in AN and 87% higher in OB subjects, compared with C subjects. After the meal, PYY increased significantly in C (+41%, P < 0.05) but not in AN or OB adolescents. Ghrelin concentrations were highest in AN subjects and lowest in the OB group, compared with C subjects and fell significantly by 25% in all three groups. GIP concentrations were lower in AN subjects throughout the test and increased in all three groups after the mixed meal. AN adolescents reported being less hungry than OB and C adolescents. There was a negative correlation between fasting ghrelin (but not PYY or GIP) and BMI and insulin (r2= 0.33) and a positive correlation between the decrease in hunger 15 min after the meal and PYY concentrations at 15 min (r2= 0.20). In conclusion, the blunted PYY response to a meal in OB adolescents suggests that PYY plays a role in the pathophysiology of obesity. Ghrelin is unlikely to play a causal role in anorexia nervosa or obesity. The lower GIP observed in AN subjects despite a similar caloric intake may appropriately prevent an excessive insulin response in these patients.

Gastric Emptying, CCK Release, and Satiety in Weight-Stable Obese Subjects

Scintigraphic gastric emptying studies are far from conclusive in obesity. The aim was to investigate gastric emptying and CCK release in weight-stable obese subjects on their usual diet and to study the impact of factors known to determine gastric emptying. Patients entering a weight reduction program were asked to participate in a study examining gastric emptying by scintigraphy and CCK release in response to a meal with questionnaires on feelings of satiety. Forty-five patients (9 M, 36 F) with a mean (SD) BMI of 37.0 (4.0) kg/m² entered the study. The mean T₅₀ (emptying of 50%) of fluids was 20.7 (10.3) min, and that of solids 141.9 (168.3) min. The percentage emptying of solids was 34.5 (19.9)%/hr. CCK values peaked within 42 min and paralleled the subjective ratings of satiety but did not correlate with gastric emptying. Five of 45 subjects (11%) had very prolonged gastric emptying of solids; they showed higher caloric intakes and higher insulin levels. They did not differ in CCK values and ratings of satiety but scored higher in being active and awake. Without these five subjects the T₅₀ of solids was 94.3 (36.1) min, and the percentage of emptying 37.9 (18.4)%/hr. Liquid emptying was faster and solid emptying similar compared with those of normal-weight individuals. Height, fat-free mass, and waist-hip circumference were positively related to solid emptying. In weight-stable obese subjects liquid emptying was faster and solid emptying similar to those in normal-weight subjects. Higher caloric intakes and insulin levels were present in subjects with prolonged solid emptying; they also appeared more vigilant. Body size and composition were the only determinants suggesting a faster solid emptying in taller and muscular subjects or in subjects with more intraabdominal fat.

Prevention of Atelectasis Formation During the Induction of General Anesthesia in Morbidly Obese Patients

Atelectasis caused by general anesthesia is increased in morbidly obese patients. We have shown that application of positive end-expiratory pressure (PEEP) during the induction of anesthesia prevents atelectasis formation in nonobese patients. We therefore studied the efficacy of PEEP in morbidly obese patients to prevent atelectasis. Twenty-three adult morbidly obese patients (body mass index >35 kg/m(2)) were randomly assigned to one of two groups. In the PEEP group, patients breathed 100% oxygen (5 min) with a continuous positive airway pressure of 10 cm H(2)O and, after the induction, mechanical ventilation via a face mask with a PEEP of 10 cm H(2)O. In the control group, the same induction was applied but without continuous positive airway pressure or PEEP. Atelectasis, determined by computed tomography, and blood gas analysis were measured twice: before the induction and directly after intubation. After endotracheal intubation, patients of the control group showed an increase in the amount of atelectasis, which was much larger than in the PEEP group (10.4% +/- 4.8% in control group versus 1.7% +/- 1.3% in PEEP group; P < 0.001). After intubation with a fraction of inspired oxygen of 1.0, PaO(2) was significantly higher in the PEEP group compared with the control group (457 +/- 130 mm Hg versus 315 +/- 100 mm Hg, respectively; P = 0.035) We conclude that in morbidly obese patients, atelectasis formation is largely prevented by PEEP applied during the anesthetic induction and is associated with a better oxygenation.

IMPLICATIONS

Application of positive end-expiratory pressure during induction of general anesthesia in morbidly obese patients prevents atelectasis formation and improves oxygenation. Therefore, this technique should be considered for anesthesia induction in morbidly obese patients.

Regulation of gastric motility at simulated high altitude in conscious rats

The aim of the present study was to examine the effects of acute exposure to hypobaric hypoxia on gastric and colonic motilities. Wistar rats, which were instrumented chronically with strain gauge force transducer to measure gastric and colonic motilities, were exposed acutely to hypobaric hypoxia [0.5 atmosphere absolute (ATA, 380 Torr)] over 1 h. In a separate group, the gastric branches of the vagal nerves were cut and underwent the same experimental protocol. Each contraction wave of the stomach and colon was analyzed into frequency and area under the curves, which were then averaged every 10 min. Acute exposure to 0.5 ATA resulted in significant (P < 0.05) decreases in frequency and area of gastric contraction wave by 0.5 +/- 0.1 cycles/min and 64.6 +/- 4.0%, respectively. Gastric vagotomy abolished completely the suppression in the area observed in the intact rats during the 0.5-ATA exposures. Colonic motility increased significantly only at the start and end of exposure to 0.5 ATA and sham exposure [1 ATA (760 Torr), time control] in both intact and vagotomized rats. These data suggest that the acute suppression of the area of the gastric contraction wave that occurred during 0.5-ATA exposure is likely to be mediated by the vagal nerve.

Laparoscopy-assisted distal gastrectomy for early gastric cancer: is it beneficial for patients of heavier weight?

OBJECTIVE

In this retrospective review, we evaluated the advantages and disadvantages of LADG for patients of heavier weight with early gastric cancer.

SUMMARY BACKGROUND DATA

LADG has been used to treat early gastric cancer. We and others have reported less operative blood loss, less pain, early recovery of bowel activity, early restart of oral intake, and a shorter hospital stay with LADG compared with a conventional open method. There is, however, little information on the advantages of LADG for obese patients with early gastric cancer.

METHODS

Between January 1996 and March 2002, 76 patients with preoperatively diagnosed early gastric carcinoma underwent LADG in our department. We classified these patients into 2 groups on the basis of body mass index (BMI). Nineteen patients had a high-BMI (>/= 24.2 kg/m2), and 57 patients had a normal-BMI (<24.2 kg/m2). We collected data by retrospectively reviewing the medical charts.

RESULTS

Extension of the minilaparotomic incision or conversion to laparotomy was needed in 6 (32%) of the 19 patients in the high-BMI group, whereas only 3 (5%) of 57 patients in the normal-BMI group required either. In the high-BMI group, Roux-en-Y anastomosis rather than Billroth I anastomosis was adopted more often than in the normal-BMI group, due to the difficulty of the reconstruction (58% versus 4%, P = 0.001). Significantly longer operative time (370 +/- 61 minutes versus 317 +/- 58 minutes, P = 0.015) and prolonged recovery of bowel activity (3.5 +/- 1.0 days versus 2.6 +/- 1.0 days, P = 0.007) were observed in the patients in the high-BMI group.

CONCLUSIONS

In the current study, LADG in patients of heavier weight was accompanied by more technical difficulties, and the disadvantages of longer operative time and delayed recovery of bowel activity was observed in patients of heavier weight. Heavier weight appears to be an ominous factor in the successful completion of LADG and should be considered in the decision to use LADG. There are still benefits of a decreased incidence of serious wound and hernia complications in successful cases.

Role of the small intestine in postpartum weight retention in mice

BACKGROUND

Approximately 25% of women retain 5 kg of the weight gained during pregnancy, but the physiologic factors underlying excessive postpartum weight gain are not known.

OBJECTIVE

The objective of the study was to determine whether pregnancy-related adaptive increases in intestinal nutrient transport are retained after parturition and therefore contribute to postpartum weight gain.

DESIGN

We measured body weight and intestinal nutrient transport in virgin (V, control), primiparous (P, one pregnancy), and multiparous (M, 3 pregnancies) mice at parturition (day 1), during lactation (days 14 and 21), at weaning (day 28), after weaning (day 40), and during aging (days 70, 120, 200, and 300).

RESULTS

In M and P mice, body weight and the weight and length of the small intestine were greatest during lactation; they then decreased but did not return to prepregnancy values until 300 d after parturition. Intestinal villus heights were maximal at lactation and remained high < or = 200 d after parturition. Total intestinal transport capacity for D-glucose, D-fructose, and L-proline was also greatest during lactation, and the lactation-enhanced transport capacity was retained < or = 70 d after parturition. M mice retained more body weight and intestinal transport capacity postpartum than did P mice. Aging per se had little or no effect on body weight or intestinal weight, length, and nutrient transport. The dramatic, lactation-related increases in intestinal nutrient transport capacity were due mainly to increases in intestinal mass.

CONCLUSIONS

Postpartum retention of pregnancy- and lactation-related increases in intestinal nutrient uptake capacity may play a significant role in postpartum body weight retention. These adaptive increases may be cumulative and may result in greater weight retention in mice with multiple pregnancies.

Bilio pancreatic diversion following failure of laparoscopic adjustable gastric banding

BACKGROUND

This study examines the failure rate with laparoscopic adjustable gastric banding (LABG) and results of band removal with synchronous biliopancreatic diversion without (BPD) or with duodenal switch (BPDDS).

METHODS

Failure of LAGB was defined as removal of the band due to insufficient weight loss or a complication.

RESULTS

The band was removed in 85 of 1,439 patients (5.9%), most commonly for persistent dysphagia and recurrent slippage. The removal rate and slippage rate decreased from 10.8 and 14.2% to 2.8 and 1.3%, respectively, following introduction of the pars flaccida technique. Fifteen of 27 patients with previous open vertical banded gastroplasty (VBG) required removal of the band. Mean percentage excess weight loss 12 months following open BPD, laparoscopic BPD, open BPDDS, and laparoscopic BPDDS was 44, 37, 35, and 28%, respectively.

CONCLUSION

LAGB fails in 6% of patients and removal of the band with synchronous BPD or BPDDS can be performed laparoscopically. Patients with failed primary VBG have a high failure rate with LAGB.

Effects of gender and menstrual cycle on colonic transit time in healthy subjects

BACKGROUND

Measuring colonic transit time (CTT) by the radio-opaque marker method is simple, widely available and important for the diagnosis of slow transit constipation. Moreover, the effects of gender and menstrual cycle on CTT remain controversial. Thus, in this study, we examined the effects of gender and menstrual cycle on CTT in healthy subjects.

METHODS

We measured CTT in 42 healthy subjects (21M, 21F) by using a radio-opaque marker, Kolomark. Two simple abdominal radiographs were taken on the 4th and 7th days. Average daily intake of dietary fiber and menstrual history were surveyed.

RESULTS

The mean CTT of the 42 healthy subjects was 26.5 +/- 19.4 hours. The mean CTT was not significantly different between the male and female subjects (22.3 +/- 16.1 h vs. 30.1 +/- 21.4 h, p > 0.05). However, the mean CTT of 11 female subjects in the luteal phase was significantly longer than that of 10 female subjects in the follicular phase (40.9 +/- 19.0 h vs. 20.6 +/- 19.2 h, p < 0.05). Serum progesterone level, age, BMI, and the average daily intake of dietary fiber did not correlate with CTT.

CONCLUSION

The effects of the menstrual cycle should be considered in interpreting CTT in young women.

Infrared spectrometry based 13C-octanoic acid breath test in measuring human solid gastric emptying

BACKGROUND AND AIMS

Because of the convenience of non-dispersive infrared spectrometry (NDIRS), we attempted to validate the usefulness of NDIRS compared with scintigraphy in human solid gastric emptying (GE) measurement, and tried to establish the normal range of solid GE based on NDIRS.

METHODS

Twelve healthy volunteers (three men, nine women) were recruited for simultaneous scintigraphy and 13C-octanoic acid breath test (13C-OABT) studies. Stomach half-emptying time (t1/2) and lag phase (tlag) were the two main GE parameters measured and correlated. The breath samples were analyzed using NDIRS every 10-15 min for a total of 6 h, while scintigraphy was taken minute by minute for the first 30 min, then hourly for 4 h. Another 32 healthy volunteers (19 men, 13 women) received only the 13C-OABT to measure their solid GE.

RESULTS

A significant correlation for t1/2 was found between the breath test and scintigraphy (r = 0.85, P = 0.001), while tlag was also positively correlated (r = 0.73, P = 0.007). The reference range of t1/2B based on all 44 subjects was 89.4-185.1 min (135.9 +/- 21.1 min (mean +/- SD)), while the range for tlagB was 37.1-117.8 min (81.9 +/- 17.4 min). No demographic characteristics were found to influence the GE parameters.

CONCLUSIONS

13C-octanoic acid breath test determined by NDIRS is a simple, non-invasive and reliable measurement, which may provide an 'office-based' tool to detect solid GE.

Extended effects of evening meal carbohydrate-to-fat ratio on fasting and postprandial substrate metabolism

BACKGROUND

High-fat and high-carbohydrate diets lead to insulin resistance, gastrointestinal adaptation, and high plasma triacylglycerol concentrations. It is unclear, however, how rapidly these changes occur.

OBJECTIVE

We sought to determine the effects of both high-fat and high-carbohydrate evening meals on parameters of insulin resistance, hypertriglyceridemia, and gastrointestinal hormones.

DESIGN

Twelve healthy men were studied on 4 separate occasions. On 2 occasions, the subjects received a high-fat evening meal (62% of energy from fat) and on the other 2 occasions the subjects received a low-fat evening meal (16% of energy from fat). The morning after each meal the subjects were administered either an oral-fat-tolerance test or an oral-glucose-tolerance test. Plasma samples were analyzed for glucose, insulin, fatty acids, 3-hydroxybutyrate, triacylglycerol, pancreatic polypeptide, peptide YY, and cholecystokinin. Postchallenge data were analyzed by two-way analysis of variance with interaction and fasting concentrations analyzed by repeated-measures analysis of variance.

RESULTS

Fasting plasma concentrations of triacylglycerol were significantly elevated 12 h after each evening meal, but fatty acid and 3-hydroxybutyrate concentrations were reduced. No effects on glucose or insulin concentrations were detected. The high-fat evening meals elevated plasma cholecystokinin concentrations, reduced fasting concentrations of pancreatic polypeptide, and had no significant effect on peptide YY concentrations. The ratio of fat to carbohydrate in the evening meal produced significant effects on plasma triacylglycerol and fatty acids during both the oral-fat-tolerance and oral-glucose-tolerance tests.

CONCLUSIONS

The present study showed that the effects of high-fat and high-carbohydrate evening meals persist at least overnight and suggests that knowledge of recent dietary history is essential to the effective design of metabolic studies.

Nutrient absorption and intestinal adaptation with ageing

Malabsorption of carbohydrates, lipids, amino acids, minerals and vitamins has been described in the elderly. The ability of the intestine to adapt may be impaired in the elderly and this may lead to further malnutrition. Dietary manipulation may prove to be useful to enhance the needed intestinal absorption with ageing. There is an age-associated increase in the prevalence of dyslipidaemia as well as diabetes. These conditions may benefit from nutritional intervention targeted at reducing the absorption of some nutrients. With the continued characterization of the proteins involved in sterol and fatty acid absorption, therapeutic interventions to modify absorption may become available in the future.

Is there a role for gastric accommodation and satiety in asymptomatic obese people?

OBJECTIVE

The relationships of gastric accommodation and satiety in moderately obese individuals are unclear. We hypothesized that obese people had increased gastric accommodation and reduced postprandial satiety. The objective of this study was to compare gastric accommodation and satiety between obese and non-obese asymptomatic subjects.

RESEARCH METHODS AND PROCEDURES

In 13 obese (body mass index [BMI] > or = 30 kg/m(2); mean BMI, 37.0 +/- 4.9 kg/m(2)) and 19 non-obese control subjects (BMI < 30 kg/m(2); mean BMI, 26.2 +/- 2.9 kg/m(2)), we used single photon emission computed tomography to measure fasting and postprandial gastric volumes and expressed the accommodation response as the ratio of postprandial/fasting volumes. The satiety test measured maximum tolerable volume of ingestion of liquid nutrient meal (Ensure) and symptoms 30 minutes after cessation of ingestion.

RESULTS

Total fasting and postprandial gastric volumes and the ratio of postprandial/fasting gastric volume were not different between asymptomatic obese and control subjects. However, the fasting volume of the distal stomach was greater in obese than in control subjects. Maximum tolerable volume of ingested Ensure and aggregate symptom score 30 minutes later were also not different between obese and control subjects.

DISCUSSION

Asymptomatic obese individuals (within the BMI range of 32.6 to 48 kg/m(2)) did not show either increased postprandial gastric accommodation or reduced satiety. These data suggest that gastric accommodation is unlikely to provide an important contribution to development of moderate obesity.

Effect of a lacto-ovo vegetarian diet on fasting small intestinal motility

BACKGROUND

Changes in diet can alter gastric and small intestinal (SI) motility. The effects of a vegetarian diet on fasting SI motility are unknown.

METHODS

Manometric studies were performed in 9 lacto-ovo vegetarians (7 women) and 9 omnivores (7 women) of similar age and body mass index. On each study day, manometry was used to assess SI motility for 5 h, or 3 complete cycles of the interdigestive motor complex (IDMC). Lacto-ovo vegetarians were studied once: omnivores were studied twice, on their usual diet, and after consuming a 14-day lacto-ovo vegetarian diet. Diet diaries were kept for 5 days prior to each manometric study. Data were analysed for dietary composition and for cycle length and duration of each phase (I, II and III) of the IDMC.

RESULTS

Dietary intake did not differ between chronic vegetarians and chronic omnivores apart from a trend to higher fibre intake (29 +/- 3 versus 20 +/- 3 g/day; P = 0.058). Omnivores eating a vegetarian diet showed a trend to decreased alcohol consumption (P = 0.068), but did not increase their fibre intake (20 +/- 3 versus 21 +/- 3 g/day). Neither cycle length nor duration of each IDMC phase differed between chronic vegetarians and chronic omnivores. After 14 days of a vegetarian diet, omnivores had a reduction in cycle length (128 +/- 19 versus 86 +/- 12 min; P = 0.02), with a non-significant reduction of Phase II (99 +/- 20 versus 50 +/- 8 min: P = 0.066).

CONCLUSIONS

A chronic vegetarian diet has no major effect on fasting SI motility; but acute dietary change may alter the cycle length and component phases of the IDMC.

Weight loss and delayed gastric emptying following a South American herbal preparation in overweight patients

BACKGROUND

Obesity and overweight may soon affect more than half of the population in some regions of the world and are associated with diabetes, hypertension and other diseases that cause morbidity, mortality and high health-care expenditure. No one approach, whether dietetic management, medication, or commercial weight loss programme, can alone solve the problem--all potential treatments need to be investigated and exploited. Among the herbal preparations known to non-western cultures are materials which may have applications in modulating physiological processes which influence gut motility, food intake and energy balance. One such mixed herbal preparation is 'YGD' containing Yerbe Maté (leaves of Ilex paraguayenis), Guarana (seeds of Paullinia cupana) and Damiana (leaves of Turnera diffusa var. aphrodisiaca).

AIMS

This study had two distinct aims: to determine the effect of a herbal preparation 'YGD' containing Yerbe Maté, Guarana and Damiana on gastric emptying; to determine the effect of the same preparation on weight loss over 10 days and 45 days and weight maintenance over 12 months.

METHODS

Gastric emptying was observed using ultrasound scanning in seven healthy volunteers following YGD and placebo capsules taken with 420 mL apple juice. Body weight was observed before and after 10 days of treatment with three YGD capsules or three placebo capsules before each meal for 10 days in 44 healthy overweight patients attending a primary health care centre. Forty-seven healthy overweight patients entered a double-blind placebo-controlled parallel trial of three capsules of YGD capsules before each main meal for 45 days compared with three placebo capsules on body weight. Body weight was monitored in 22 patients who continued active (YGD capsules) treatment for 12 months.

RESULTS

The herb preparation YGD was followed by a prolonged gastric emptying time of 58 +/- 15 min compared to 38 +/- 7.6 min after placebo (P = 0.025). Body weight reductions were 0.8 +/- 0.05 kg after YGD capsules compared to 0.3 +/- 0.03 kg after placebo capsules over 10 days, and 5.1 +/- 0.5 kg after PGD capsules compared to 0.3 +/- 0.08 kg after placebo over 45 days. Active treatment with YGD capsules resulted in weight maintenance of the group (73 kg at the beginning and 72.5 kg at the end of 12 months).

CONCLUSIONS

The herbal preparation, YGD capsules, significantly delayed gastric emptying, reduced the time to perceived gastric fullness and induced significant weight loss over 45 days in overweight patients treated in a primary health care context. Maintenance treatment given in an uncontrolled context resulted in no further weight loss, nor weight regain in the group as a whole. The herbal preparation is thus shown to be one that significantly modulates gastric emptying. Further clinical studies with dietetic monitoring of energy intake, dietary quality, satiety ratings, body weight and body composition are now indicated, and examination of the active principles contained in the three herbal components may prove rewarding.

Treatment of morbid obesity with laparoscopic adjustable gastric banding affects esophageal motility

BACKGROUND

Laparoscopic adjustable gastric banding has become the prefered method for the surgical treatment of morbid obesity in Europe. It is not known whether this procedure may induce gastroesophageal reflux and whether it may impair esophageal peristalsis.

METHODS

Laparoscopic adjustable gastric banding (Swedish band) was performed in 43 patients (median body mass index [BMI] 42.5 kg/m(2)). Preoperatively and 6 months postoperatively all patients were assessed for reflux symptoms. In addition all patients underwent preoperative and postoperative endoscopy, esophageal barium studies and manometry, and 24-hour esophageal pH-monitoring.

RESULTS

The median BMI dropped significantly to 33.1 kg/m(2) (P <0.05). Preoperatively 12 patients complained of reflux symptoms. Mild esophagitis was detected in 10 patients. Postoperatively only 1 patient complained of heartburn and mild esophagitis was diagnosed in another patient. None of the patients had dysphagia. Preoperatively a defective LES and pathologic pH-testing were found in 9 and 15 patients, respectively. These parameters were normal in all of the patients postoperatively. Postoperatively there was significant impairment of LES relaxation and deterioration of esophageal peristalsis with dilatation of the esophagus in some of the patients.

CONCLUSION

Laparoscopic adjustable gastric banding provides a sufficient antireflux barrier and therefore prevents pathologic gastroesophageal reflux. However, it impairs relaxation of the LES, leading to weak esophageal peristalsis.