Human gut hormone profiles in patients with short bowel syndrome

Problem or solution: The strange story of glucagon

Globally, 13% of the world's adult population is obese, and more than 400 million people suffer from diabetes. These conditions are both associated with significant morbidity, mortality and financial cost. Therefore, finding new pharmacological treatments is an imperative. Relative hyperglucagonaemia is seen in all types of diabetes, and has been implicated in its pathogenesis. Consequently, clinical trials are underway using drugs which block glucagon activity to treat type 2 diabetes. Conversely, exogenous glucagon can increase energy expenditure. Therefore, researchers are designing peptides that combine activation of the glucagon receptor with further incretin properties, which will treat obesity while mitigating the hyperglycaemic effects of glucagon. This review will discuss these conflicting physiological properties of glucagon, and the attempts to harness these effects pharmacologically.

Physiology, pathophysiology and therapeutic implications of enteroendocrine control of food intake

With the increasing prevalence of obesity and its associated comorbidities, strides to improve treatment strategies have enhanced our understanding of the function of the gut in the regulation of food intake. The most successful intervention for obesity to date, bariatric surgery effectively manipulates enteroendocrine physiology to enhance satiety and reduce hunger. Areas covered: In the present article, we provide a detailed overview of the physiology of enteroendocrine control of food intake, and discuss its pathophysiologic correlates and therapeutic implications in both obesity and gastrointestinal disease. Expert commentary: Ongoing research in the field of nutrient sensing by L-cells, as well as understanding the role of the microbiome and bile acid signaling may facilitate the development of novel strategies to combat the rising population health threat associated with obesity. Further refinement of post-prandial satiety gut hormone based therapies, including the development of chimeric peptides exploiting the pleiotropic nature of the gut hormone response, and identification of novel methods of delivery may hold the key to optimization of therapeutic modulation of gut hormone physiology in obesity.

The role of peptide YY in gastrointestinal diseases and disorders (review)

Peptide YY (PYY) is affected in several gastrointestinal diseases and disorders. Changes in PYY appear to be an adaptive response to alterations in pathophysiological conditions caused by the disease. This applies to gastrointestinal diseases/disorders such as irritable bowel syndrome, inflammatory bowel disease, celiac disease, systemic sclerosis, and post-intestinal resection. By contrast, the changes in PYY in chronic idiopathic slow transit constipation (CST) seem to be of a primary nature, and may be one etiological factor of the disease. Abnormalities in PYY seem to contribute to the development of symptoms present in irritable bowel syndrome, inflammatory bowel disease, gastroenteropathy in long-standing diabetes and CST. The changes in PYY could, however, be favorable in some gastrointestinal disorders such as celiac disease, systemic sclerosis and post-intestinal resection state. Investigating changes in PYY in gastrointestinal diseases/disorders could be beneficial in clinical practice, where a receptor agonist or an antagonist can be used as a drug, depending on the condition. Similar to other neuroendocrine peptides/amines of the gut, PYY has broad physiological/pharmacological effects: it can bind to and activate several receptors with independent actions. Thus, in order to use PYY as a drug, receptor-specific agonists or antagonists need to be developed.

Obesity treatment: novel peripheral targets

Our knowledge of the complex mechanisms underlying energy homeostasis has expanded enormously in recent years. Food intake and body weight are tightly regulated by the hypothalamus, brainstem and reward circuits, on the basis both of cognitive inputs and of diverse humoral and neuronal signals of nutritional status. Several gut hormones, including cholecystokinin, glucagon-like peptide-1, peptide YY, oxyntomodulin, amylin, pancreatic polypeptide and ghrelin, have been shown to play an important role in regulating short-term food intake. These hormones therefore represent potential targets in the development of novel anti-obesity drugs. This review focuses on the role of gut hormones in short- and long-term regulation of food intake, and on the current state of development of gut hormone-based obesity therapies.

Effects of mid-jejunal compared to duodenal glucose infusion on peptide hormone release and appetite in healthy men

INTRODUCTION

Cells containing GIP and CCK predominate in the upper small intestine, while those containing GLP-1 are located more distally. Our aim was to compare the hormonal, glycemic and appetite responses to different sites of glucose delivery.

METHODS

Ten healthy males were each studied twice, in randomized order. A catheter was positioned with openings 15 cm beyond the pylorus ("duodenal"), and 100 cm beyond ("mid-jejunal"). On one day, glucose was infused into the duodenum (1 kcal/min) and saline into the mid-jejunum, for 90 min. On the other day, the infusion sites were reversed. Blood was sampled frequently, and hunger was scored by questionnaires. The tube was removed and energy intake measured from a buffet meal.

RESULTS

Stimulation of CCK and suppression of hunger were greater (each P<0.05), and energy intake less (P=0.05), with duodenal compared to mid-jejunal glucose infusion. Blood glucose, GIP, and insulin did not differ, and there was minimal GLP-1 increment on either day.

CONCLUSIONS

There is regional variation in CCK, but not incretin hormone release, in the upper small intestine, and modest differences in the site of glucose exposure affect appetite and energy intake.

Characterization of weight loss and weight regain mechanisms after Roux-en-Y gastric bypass in rats

Roux-en-Y gastric bypass (RYGB) is the most effective therapy for morbid obesity, but it has a ∼20% failure rate. To test our hypothesis that outcome depends on differential modifications of several energy-related systems, we used our established RYGB model in Sprague-Dawley diet-induced obese (DIO) rats to determine mechanisms contributing to successful (RGYB-S) or failed (RYGB-F) RYGB. DIO rats were randomized to RYGB, sham-operated Obese, and sham-operated obese pair-fed linked to RYGB (PF) groups. Body weight (BW), caloric intake (CI), and fecal output (FO) were recorded daily for 90 days, food efficiency (FE) was calculated, and morphological changes were determined. d-Xylose and fat absorption were studied. Glucose-stimulated vagal efferent nerve firing rates of stomach were recorded. Gut, adipose, and thyroid hormones were measured in plasma. Mitochondrial respiratory complexes in skeletal muscle and expression of energy-related hypothalamic and fat peptides, receptors, and enzymes were quantified. A 25% failure rate occurred. RYGB-S, RYGB-F, and PF rats showed rapid BW decrease vs. Obese rats, followed by sustained BW loss in RYGB-S rats. RYGB-F and PF rats gradually increased BW. BW loss in RYGB-S rats is achieved not only by RYGB-induced decreased CI and increased FO, but also via sympathetic nervous system activation, driven by increased peptide YY, CRF, and orexin signaling, decreasing FE and energy storage, demonstrated by reduced fat mass associated with the upregulation of mitochondrial uncoupling protein-2 in fat. These events override the compensatory response to the drop in leptin levels aimed at conserving energy.

Upper gastrointestinal function and glycemic control in diabetes mellitus

Recent evidence has highlighted the impact of glycemic control on the incidence and progression of diabetic micro- and macrovascular complications, and on cardiovascular risk in the non-diabetic population. Postprandial blood glucose concentrations make a major contribution to overall glycemic control, and are determined in part by upper gastrointestinal function. Conversely, poor glycemic control has an acute, reversible effect on gastrointestinal motility. Insights into the mechanisms by which the gut contributes to glycemia have given rise to a number of novel dietary and pharmacological strategies designed to lower postprandial blood glucose concentrations.

Gut hormones, and short bowel syndrome: The enigmatic role of glucagon-like peptide-2 in the regulation of intestinal adaptation

Short bowel syndrome (SBS) refers to the malabsorption of nutrients, water, and essential vitamins as a result of disease or surgical removal of parts of the small intestine. The most common reasons for removing part of the small intestine are due to surgical intervention for the treatment of either Crohn's disease or necrotizing enterocolitis. Intestinal adaptation following resection may take weeks to months to be achieved, thus nutritional support requires a variety of therapeutic measures, which include parenteral nutrition. Improper nutrition management can leave the SBS patient malnourished and/or dehydrated, which can be life threatening. The development of therapeutic strategies that reduce both the complications and medical costs associated with SBS/long-term parenteral nutrition while enhancing the intestinal adaptive response would be valuable.

Currently, therapeutic options available for the treatment of SBS are limited. There are many potential stimulators of intestinal adaptation including peptide hormones, growth factors, and neuronally-derived components. Glucagon-like peptide-2 (GLP-2) is one potential treatment for gastrointestinal disorders associated with insufficient mucosal function. A significant body of evidence demonstrates that GLP-2 is a trophic hormone that plays an important role in controlling intestinal adaptation. Recent data from clinical trials demonstrate that GLP-2 is safe, well-tolerated, and promotes intestinal growth in SBS patients. However, the mechanism of action and the localization of the glucagon-like peptide-2 receptor (GLP-2R) remains an enigma. This review summarizes the role of a number of mucosal-derived factors that might be involved with intestinal adaptation processes; however, this discussion primarily examines the physiology, mechanism of action, and utility of GLP-2 in the regulation of intestinal mucosal growth.

Peripheral administration of GLP-2 to humans has no effect on gastric emptying or satiety

Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are secreted in parallel to the circulation after a meal. Intravenous (IV) GLP-1 has an inhibitory effect on gastric emptying, hunger and food intake in man. In rodents, central administration of GLP-2 increases satiety similar to GLP-1. The aim of the present study was to assess the effect of IV administered GLP-2 on gastric emptying and feelings of hunger in human volunteers. In eight (five men) healthy subjects (age 31.1+/-2.9 years and BMI 24.1+/-1.0 kg m(-2)), scintigraphic solid gastric emptying, hunger ratings (VAS) and plasma concentrations of GLP-2 were studied during infusion of saline or GLP-2 (0.75 and 2.25 pmol kg(-1) min(-1)) for a total of 180 min. Concentrations of GLP-2 were elevated to a maximum of 50 and 110 pmol l(-1) for 0.75 and 2.25 pmol kg(-1) min(-1) infusion of GLP-2, respectively. There was no effect of GLP-2 on either the lag phase (29.5+/-4.4, 26.0+/-5.2 and 21.2+/-3.6 min for saline, GLP-2 0.75 or 2.25 pmol kg(-1) min(-1), respectively) or the half emptying time (84.5+/-6.1, 89.5+/-17.8 and 85.0+/-7.0 min for saline, GLP-2 0.75 or 2.25 pmol kg(-1) min(-1), respectively). The change in hunger rating after the meal to 180 min was also unaffected by infusion of GLP-2. GLP-2 does not seem to mediate the ileal brake mechanism.

Intestinal rehabilitation and the short bowel syndrome: part 1

The management of patients with intestinal failure due to short bowel syndrome (SBS) is complex, requiring a comprehensive approach that frequently necessitates long-term, if not life-long, use of parenteral nutrition (PN). Despite tremendous advances in the provision of PN over the past three decades, which have allowed significant improvements in the survival and quality of life of these patients, this mode of nutritional support carries with it significant risks to the patient, is very costly and, ultimately, does not attempt to improve the function of the remaining bowel. Intestinal rehabilitation refers to the process of restoring enteral autonomy and, thus, allowing freedom from parenteral nutrition, usually by means of dietary, medical, and, occasionally, surgical strategies. While recent investigations have focused on the use of trophic substances to increase the absorptive function of the remaining gut, whether intestinal rehabilitation occurs as a consequence of enhanced bowel adaptation or is simply a result of an optimized, comprehensive approach to the care of these patients remains unclear. In Part 1 of this review, an overview of SBS and pathophysiological considerations related to the remaining bowel anatomy in these patients will be provided. Additionally, a review of intestinal adaptation and factors that may enhance the adaptive process, focusing on evidence derived from animal studies, will also be discussed. In Part 2, relevant data on the development of intestinal adaptation in studies involving humans will be reviewed as will the general management of SBS. Lastly, the potential benefits of a multidisciplinary intestinal rehabilitation program in the care of these patients will also be discussed.

Glucagon-like peptide 2 function in domestic animals

Glucagon-like peptide 2 (GLP-2) is a member of family of peptides derived from the proglucagon gene expressed in the intestines, pancreas and brain. Tissue-specific posttranslational processing of proglucagon leads to GLP-2 and GLP-1 secretion from the intestine and glucagon secretion from the pancreas. GLP-2 and GLP-1 are co-secreted from the enteroendocrine L-cells located in distal intestine in response to enteral nutrient ingestion, especially carbohydrate and fat. GLP-2 secretion is mediated by direct nutrient stimulation of the L-cells and indirect action from enteroendocrine and neural inputs, including GIP, gastrin-releasing peptide (GRP) and the vagus nerve. GLP-2 is secreted as a 33-amino acid peptide and is rapidly cleaved by dipeptidylpeptidase IV (DPP-IV) to a truncated peptide which acts as a weak agonist with competitive antagonistic properties. GLP-2 acts to enhance nutrient absorption by inhibiting gastric motility and secretion and stimulating nutrient transport. GLP-2 also suppresses food intake when infused centrally. The trophic actions of GLP-2 are specific for the intestine and occur via stimulation of crypt cell proliferation and suppression of apoptosis in mucosal epithelial cells. GLP-2 reduces gut permeability, bacterial translocation and proinflammatory cytokine expression under conditions of intestinal inflammation and injury. The effects of GLP-2 are mediated by a G-protein-linked receptor that is localized to the intestinal mucosa and hypothalamus. The intestinal localization of the GLP-2R to neural and endocrine cells, but not enterocytes, suggests that its actions are mediated indirectly via a secondary signaling mechanism. The implications of GLP-2 in domestic animal production are largely unexplored. However, GLP-2 may have therapeutic application in treatment of gastrointestinal injury and diarrheal diseases that occur in developing neonatal and weanling animals.

Enhancing bowel adaptation in short bowel syndrome

Malabsorption of both nonessential and essential nutrients, fluid, and electrolytes will, if not compensated for by increased intake, lead to diminished body stores and to subclinical and eventually clinical deficiencies. By definition, intestinal failure prevails when parenteral support is necessary to maintain nutritional equilibrium. After intestinal resection, adaptation, a progressive recovery from the malabsorptive disorder, may be seen. Research has focused on optimizing remnant intestinal function through dietary or pharmacologic interventions. In this review, factors responsible for the morphologic and functional changes in the adaptive processes are described. Results of clinical trials employing either growth hormone and glutamine or glucagon-like peptide-2 in short bowel patients are presented.

Reversed bowel segments for the treatment of short bowel syndrome: assessment of their minimal length in correlation with electromyographic pattern in the rat

Reversal of a distal intestinal loop is a surgical therapy intended to cure rapid intestinal transit in short bowel syndrome. To be active, a reversed loop must present a retrograde propagation of electromyographic patterns and must not be so long as to cause total obstruction. The aim of the current study was to propose methods to calculate the minimal length of the intestinal reversed loop taking into consideration the two previous conditions. Intestinal electromyograms were recorded in 65 rats at short-term (4 days after surgery) and ten rats at long-term (50 days after surgery). Control rats demonstrated that the preprandial regular spiking activity (RSA) of the migrating myoelectrical complex (MMC) extended simultaneously a definite part of the intestine which corresponds to the minimal length to reverse. A similar result can be obtained from a trigonometric representation. Whatever the method, the minimal lengths allowing the recording of RSA decreased along the rat intestine from 6 cm (proximal jejunum) to 4 cm (distal ileum). The experiments demonstrated that shorter loops did not present the preprandial RSA. In conclusion, the minimal reversed length depends on intestinal electromyographic parameters and, thereby, on the intestinal level.

Circulating oxyntomodulin-like immunoreactivity in healthy children and children with celiac disease

BACKGROUND

The aim of the study was to evaluate the new hormonal entity oxyntomodulin-like immunoreactivity in malabsorption states, and to assess its potential in celiac disease management.

METHODS

We measured basal and postprandial oxyntomodulin-like immunoreactivity values in 35 children divided into 3 groups: group 1 was composed of 13 children with celiac disease, either under a gluten-free diet (8 patients) or normal diet (5 patients); group 2 was composed of 8 children hospitalized for gastroenteritis or chronic diarrhea, without biological evidence of malabsorption nor abnormal jejunal mucosa; group 3 was composed of 22 control subjects.

RESULTS

Fasting and meal-stimulated levels in the control group were 71+/-10 and 130+/-26 pmol/l, respectively. Mean concentrations were elevated in patients with celiac disease (basal = 349+/-254 pmol/l, postprandial = 446+/-332 pmol/l) and in the group 2 (basal = 139+/-58 pmol/l, postprandial = 218+/-85 pmol/l), but the difference with control subjects did not reach statistical significance. In children with celiac disease, basal and stimulated values correlated with the degree of malabsorption as assessed by hemoglobin (p = 0.006 and p = 0.01, respectively) and serum folate concentrations (p = 0.03 and p = 0.02, respectively).

CONCLUSIONS

Oxyntomodulin-like immunoreactivity is noticeably higher in healthy children than previously measured in healthy adult subjects. This hormonal parameter is not an adequate diagnostic tool in celiac disease. Nevertheless, in the context of celiac disease, its elevation reflects the degree of malabsorption and may provide a quantitative approach of the extent of mucosal damage.

Reduction of gut hypoplasia and cachexia in tumor-bearing rats maintained on total parenteral nutrition and treated with peptide YY and clenbuterol

Prevention of gut hypoplasia associated with total parenteral nutrition (TPN) was investigated in 67 adult male Fisher 344 rats. Mass and protein content of the small intestine was reduced by 31% and 39%, respectively, after 7 d of TPN in tumor-bearing (TB) rats. Coinfusing peptide YY (PYY; 1 nmol.kg-1.h-1) and treating the rats with the anabolic beta-adrenergic agonist, clenbuterol (CLE; 2 mg.kg-1.d-1), resulted in significant savings in small intestine weight (26% increase) and protein (42% increase). Although the colon also exhibited a significant decrease in mass (31%), none of the treatment combinations were effective in this region of the gut. Histologic analysis of ileum suggested that the additive effects of PYY and CLE were due to differential effects of these compounds on mucosal and muscular tissues, respectively. This combination of treatments also resulted in significant savings (30% increase) in gastrocnemius protein, suggesting a reduction in the cachectic response. These results suggest that TPN-induced gut hypoplasia and cancer cachexia may be reduced by the proper combination of nutritional, hormonal, and pharmacologic treatments. In addition, the anabolic effects of various treatments may be additive to counteract TPN-induced gut atrophy.

Peptide YY selectively stimulates expression of the colonocytic phenotype

Peptide YY (PYY) is produced by colonic mucosal endocrine cells and modulates gastrointestinal endocrine activity through specific Y-receptors. The direct effects of PYY on intestinal mucosal growth and differentiation remain uncharacterized. The abundance of PYY in colonic mucosa suggests that PYY acts locally to maintain colonocytic differentiation. We tested this hypothesis in human Caco-2 intestinal epithelial cells, which express alkaline phosphatase (AP) and dipeptidyl dipeptidase (DP), brush-border enzymes differentially concentrated in large and small intestinal mucosa, respectively. The effects of PYY on enzyme specific activity were compared with those of pancreatic polypeptide, neuropeptide-Y, vasoactive intestinal peptide, pentagastrin, bombesin, and selective Y1- and Y2-receptor agonists. Brush-border enzyme activity was assessed by AP and DP specific activity in cell lysates quantitated spectrophotometrically following synthetic substrate digestion. PYY, neuropeptide-Y, pancreatic polypeptide, and vasoactive intestinal peptide (10(-7) mol/L) stimulated AP activity. PYY brought about the greatest increase (38.0%+/-11.0%, n=48). Only PYY decreased DP specific activity (7.9%+/-2.2%, n=48). The Y2-agonist but not the Y1-agonist mimicked these PYY effects (increasing AP 28.3%+/-3.5% and decreasing DP 10.4%+/-3.6%). These data suggest that PYY promotes differentiation toward a colonocytic phenotype in Caco-2 intestinal epithelial cells and that this effect may be mediated through the Y2-receptor subtype.

Gastrointestinal hormones in short bowel syndrome. Peptide YY may be the 'colonic brake' to gastric emptying

BACKGROUND

Short bowel patients with a jejunostomy have large volume stomal outputs, which may in part be due to rapid gastric emptying of liquid. Short bowel patients with a preserved colon do not have such a high stool output and gastric emptying of liquid is normal.

AIMS

To determine if differences in the gastric emptying rate between short bowel patients with and without a colon can be related to gastrointestinal hormone changes after a meal.

SUBJECTS

Seven short bowel patients with no remaining colon (jejunal length 30-160 cm) and six with jejunum in continuity with a colon (jejunal length 25-75 cm), and 12 normal subjects.

METHODS

The subjects all consumed a 640 kcal meal; blood samples were taken for 180 minutes for measurement of gastrointestinal hormones.

RESULTS

Patients with a colon had high fasting peptide YY values (median 71 pmol/l with a colon; 11 pmol/l normal subjects, p < 0.005) with a normal postprandial rise, but those without a colon had a low fasting (median 7 pmol/l, p = 0.076) and a reduced postprandial peptide YY response (p < 0.050). Motilin values were high in some patients without a colon. In both patient groups fasting and postprandial gastrin and cholecystokinin values were high while neurotensin values were low. There were no differences between patient groups and normal subjects in enteroglucagon, pancreatic polypeptide, or somatostatin values.

CONCLUSIONS

Low peptide YY values in short bowel patients without a colon may cause rapid gastric emptying of liquid. High values of peptide YY in short bowel patients with a retained colon may slow gastric emptying of liquid and contribute to the "colonic brake'.

Preservation of intestine protein by peptide YY during total parenteral nutrition

Maintaining rats on TPN for 7 days was associated with a 50% reduction in gut mass and protein content. Co-infusing PYY with total parenteral nutrition (TPN) resulted in significant savings in jejunal wet mass and elevated protein content of jejunum, ileum and colon as compared with rats maintained on TPN alone. No significant effects of PYY on plasma amino acid profile were noted. Although minor alterations in mucosal polyamines were observed in rats maintained on TPN, co-infusion of PYY had no significant effect on gut polyamine concentrations. These results suggest that PYY has trophic effects upon the gut during otherwise catabolic conditions. Therefore, co-infusion of PYY with TPN may suggest methods whereby loss of intestinal mucosa and atrophy-associated complications of TPN may be modulated.

Interrelation of intracellular proteases with total parenteral nutrition-induced gut mucosal atrophy and increase of mucosal macromolecular transmission in rats

Total parenteral nutrition (TPN) is known to induce mucosal atrophy and to increase macromolecular transmission of the small intestine. The potential participation of various proteases in that process was investigated. Male Wistar rats were randomly divided into two groups: the TPN group (n = 11) received a standard TPN (250 kcal/kg per day, 1.78 g nitrogen/kg per day) and the FED group (n = 10) received a standard rat food for 1 week. This was followed by an examination of gut macromolecular transmission of fluorescein isothiocyanate dextran 70,000 (FITC-dextran) after intragastric injection and of the activities of gut mucosal cathepsins B, H, and L and of proteasome. Mucosal wet weight and protein content decreased significantly by TPN for 1 week. In both groups, the activities of all proteases in the ileum were significantly greater than in the jejunum. In the TPN group, cathepsin L and H activities in the ileum, and cathepsin B activity in both the jejunum and the ileum, were greater than those in the FED group. The portal concentration of FITC-dextran was higher than arterial and venous concentrations in the both groups. In the TPN group, the portal FITC-dextran concentration increased significantly compared with the FED group. In conclusion, active proteolysis is not associated with TPN-induced mucosal atrophy. Cathepsins activities in the ileum increase as a result of TPN. Interrelationship is implicated between increase of lysosomal protease activity and the deterioration of the intestinal barrier function, which permits macromolecular transmission.

Ileal release of glucagon-like peptide-1 (GLP-1). Association with inhibition of gastric acid secretion in humans

There is evidence that the distal intestine participates in the regulation of gastric motor and secretory function. It was the aim of this study to examine in greater detail the effects of ileal nutrient exposure on human gastric acid secretion and to investigate potential intermediary mechanisms. Twelve normal subjects were intubated with an oroileal multilumen tube assembly for gastric, duodenal, and ileal perfusion of marker and test solutions, aspiration, and intestinal manometry. We studied ileal effects on gastric acid output in the unstimulated, interdigestive state (during early phase II, N = 6), and during endogenous stimulation by intraduodenal essential amino acid perfusion, N = 6) and on release of candidate humoral mediators, peptide YY (PYY) and glucagonlike peptide-1 (GLP-1), both known inhibitors of human gastric acid secretion. Compared with ileal saline perfusion, ileal carbohydrate (total caloric load: 60 kcal) decreased interdigestive gastric acid output by 64% (P < 0.01), and endogenously stimulated output by 68%, respectively (P < 0.005). Under all experimental conditions, ileal carbohydrate increased plasma GLP-1 by 80-100% (all P < 0.005). Ileal lipid perfusion had similar inhibitory effects on gastric acid output and stimulatory effects on GLP-1 release as had ileal carbohydrate. By contrast, ileal perfusion with peptone had no or only weak effects on either acid output or plasma GLP-1. Plasma PYY concentrations and suppression of gastric secretion in response to ileal perfusions were not correlated. In humans, both interdigestive and endogenously stimulated gastric acid output are inhibited in response to intraileal carbohydrate or lipids, but not protein.(ABSTRACT TRUNCATED AT 250 WORDS)

The motor response to intestinal resection: motor activity in the canine small intestine following distal resection

BACKGROUND

The mucosal response to intestinal resection has been extensively studied; little is known of the motor response. Our aim was to evaluate motility in the intestinal remnant following distal resection.

METHODS

Motor activity, duodenocecal transit, nutrition, and absorption were studied over a 3-month period in control animals (n = 9) and in groups of dogs who had undergone 25% (n = 6), 50% (n = 5), and 75% (n = 5) distal resection.

RESULTS

Diarrhea and steatorrhea developed in each resection group, and the 75% group alone developed true short bowel syndrome. Resection did not affect migrating motor complex frequency or periodicity; phase 1 duration was shorter in the 75% group (control vs. 75%: 22 +/- 4 vs. 6 +/- 2 minutes, P < 0.03). The most striking motor effect was the development of prominent cluster activity in the distal part of the remnant in 25% and 50% resection animals and throughout the remaining intestine in the 75% group. Duodenocecal transit slowed during the study period from 13 +/- 1 to 20 +/- 2 minutes in the 50% and from 10 +/- 2 to 14 +/- 2 minutes in the 75% group (P < 0.05).

CONCLUSIONS

The initial motor response to major resections of the distal small intestine is dominated by the development of abnormal patterns. This motor disruption may contribute to the symptomatology and clinical features of the short bowel syndrome.