Background: Tegaserod is effective in treating IBS patients with constipation, and does not alter gallbladder motility in healthy individuals or in patients with IBS. However, it is not known if tegaserod affects the biliary tract in gallstone disease, so to this end the effects of tegaserod on bile composition and hepatic secretion of Richardson ground squirrels maintained on an enriched cholesterol diet were examined. Results: Animals were fed either a control (0.03%) or enriched (1%) cholesterol diet for 28 days, and treated s.c. with tegaserod (0.1 mg/kg BID) or vehicle. Bile flow, bile acid, phospholipids and cholesterol secretion were measured with standard methods. Tegaserod treatment or enriched cholesterol diet, alone or combination, did not alter body or liver weights. The enriched cholesterol diet increased cholesterol saturation index (CSI), cholesterol concentrations in gallbladder and hepatic duct bile by ~50% and decreased bile acids in gallbladder bile by 17%. Tegaserod treatment reversed these cholesterol-induced changes. None of the treatments, drug or diet, altered fasting gallbladder volume, bile flow and bile salts or phospholipid secretion in normal diet and cholesterol-fed animals. However, tegaserod treatment prevented the decreases in bile acid pool size and cycling frequency caused by the enriched cholesterol diet, consequent to re-establishing normal bile acid to concentrations in the gall bladder. Tegaserod had no effect on these parameters with normal diet animals. Conclusion: Tegaserod treatment results in increased enterohepatic cycling and lowers cholesterol saturation in the bile of cholesterol-fed animals. These effects would decrease conditions favorable to cholesterol gallstone formation. Background Irritable bowel syndrome (IBS) is a poorly understood symptom complex with abdominal pain and altered bowel function. Its basis likely involves visceral hypersensitivity and altered intestinal motility, perhaps mediated by the serotonin (5-HT) receptors [1]. IBS is not merely a motility disorder confined to the colon, but may involve the entire gut, urinary tract and gallbladder. As to the Published: 22 June 2006 Lipids in Health and Disease 2006, 5:15 doi:10.1186/1476-511X-5-15 Received: 25 April 2006 Accepted: 22 June 2006 This article is available from: http://www.lipidworld.com/content/5/1/15 © 2006 Mathison et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

We have previously shown that galantide ameliorates mild acute pancreatitis (AP), and the salivary tripeptide analogue, feG, ameliorates severe AP in mice. In this study, we compared the efficacy of combining galantide and feG with that of the individual agents in treating mild AP induced in mice with 7-hourly caerulein injections. Galantide was co-administered with each caerulein injection commencing with the first injection. feG was co-administered with the first injection of caerulein as a single intraperitoneal injection. Combination of the agents was also administered. Control animals received galantide, feG, or saline alone. Pancreata were harvested for histological examination and estimation of myeloperoxidase (MPO) activity. Plasma enzyme activities were measured. Galantide significantly reduced AP-induced hyperenzymemia by 41–49%. The combination of galantide and feG significantly reduced AP-induced hyperenzymemia by 39–40%, whereas feG alone was without effect. Plasma enzyme activity in the control groups was comparable with pre-treatment activity. Galantide, feG, and their combination significantly reduced MPO activity by 83, 44 and 74% respectively, and % abnormal acinar cells by 32, 29 and 36% respectively. This study demonstrates for the first time the beneficial effect of feG in mild caerulein-induced AP. Moreover the data indicate that the hyperenzymemia in mild caerulein-induced AP at 12h possibly reflect a larger secretory component as compared to enzyme release due to neutrophil-mediated acinar cell damage. The effects of the treatment with both peptides indicate a possible role for galantide in modulating neutrophil chemotaxis/activation and supports the hypothesis that galantide may influence neurogenic inflammation in AP.

Saliva is an exocrine secretion with the fluid and its components being dispensed into ducts. However, a sig- nificant component of salivary gland secretions is found in blood indicating endocrine secretion. The growth factors and hormones secreted into the blood by salivary glands manifest their actions in the face of stressful and often inflammatory stimuli, such as injury, trauma and infections, and they do not participate overtly in the regulation of the resting homeo- static steady state. This type of regulation is called allostasis, which encompasses the processes involved in maintaining systems balance in response to persistent changes, challenges, insults and injury. Viewing salivary gland endocrine secre- tions as having important roles in regulating responses to systemic stressors by modulating allostatic load provides a new perspective for understanding the role of salivary glands in modulation of systemic disease and pathology.

Allergen-induced inflammation manifests as allergic asthma, dermatitis, rhinitis, conjunctivitis, food allergies, and life- threatening anaphylaxis. Allergic reactions consist of an acute phase hypersensitivity reaction and late phase inflammation. Current therapeutic strategies consist of immunotherapy to induce tolerance to an allergen or pharmacotherapy to treat either the acute phase reaction or the chronic inflammation associated with allergic disease. For bronchial asthma, the allergic disease with the greatest worldwide burden, three medications (β2-adrenoceptor agonists, glucocorticoids and leukotriene antagonists) are the mainstays of therapy, which when used alone or in combination control asthma symptoms in many asthmatics. A recent anti-IgE therapy has benefited some difficult to manage patients, however a significant proportion of asthma patients do not respond well to currently available drugs. There is a need for new effective lost-cost therapies for asthma and other allergic diseases to complement existing therapies and improve long-term outcomes. There are several potential therapeutic targets including transcription factors, cytokines, chemokines and their receptors, proteases, and cell adhesion molecules. Within the next generation of anti-allergy drugs one or more will probably be a peptide or a peptide mimetic. Keywords: Allergen, induced inflammation, asthma, dermatitis, rhinitis, hypersensitivity reaction, transcription factors, cytokines, chemokines, peptide mimetic, anti-allergy drugs

The tripeptide FEG (Phe-Glu-Gly) and its D-isomer feG are potent anti-inflammatory peptides that reduce type I immediate hypersensitivity reactions (antigen-induced contraction of sensitized intestine), and inhibit the binding of CD16b (FCyRIII) antibody to human neutrophils. However, significant differences exist in the structure activity relationships (SAR) with FEG-like peptides for these two activities. By comparing biological activities to the topological features of FEG and its analogues this study identifies the distinguishing features of the peptides that explain the differential SAR on the immediate hypersensitivity reaction and CD16b antibody binding. Using DeepView (http://www.expasy.org/spdbv/), the distances between side-chain atoms and the angles between side-chain terminal carbon residues and their backbone juncture were determined. The electrostatic force field of the peptides was calculated using DeepView, which employs the GROMOS96 43B1 parameter set. The primary topological feature of FEG-like molecules that impacts the immediate hypersensitivity reaction was the relative positioning of the aromatic ring to the carboxyl group of position-2 amino acid. In contrast, the electrostatic potential of the peptides primarily determined the inhibition of CD16b antibody binding, although the separation of the carboxyl groups on position-2 amino acid and the C-terminal provided a topological component to biological activity. Thus, the topological features and the electrostatic potential of FEG and its analogues account for differential SAR, and suggest that the FEG may act on several distinct recognition sites.

Tegaserod is effective in treating IBS patients with constipation, and does not alter gallbladder motility in healthy individuals or in patients with IBS. However, it is not known if tegaserod affects the biliary tract in gallstone disease, so to this end the effects of tegaserod on bile composition and hepatic secretion of Richardson ground squirrels maintained on an enriched cholesterol diet were examined.

Tegaserod, a 5HT4 receptor partial agonist, acts as a gut motility agent. Since a high cholesterol diet is associated with altered small intestinal motility, we examined the effects of tegaserod on cholinergic contractions of intestinal longitudinal smooth muscle of ground squirrels fed either low (0.03%) or high (1%) cholesterol diet for 28 days, and treated with either vehicle or 0.1 mg/kg of tegaserod s.c. BID. In vitro contractile responses of jejunal smooth muscle segments to the muscarinic agonist, carbachol, and the nicotinic agonist, DMPP, were determined in the presence or absence of neurotransmission blocking agents. In vehicle-treated animals on a high cholesterol diet, carbachol increased jejunual tonic contractions 55%. Tetrodotoxin (10 -7 M), but not the nicotinic antagonist hexamethonium (10 -5 M), blocked this increase, suggesting that the cholesterol diet increased nerve-mediated, muscarinic neuromuscular transmission. The nicotinic agonist DMPP also increased (~100%) jejunal contractions in high cholesterol diet animals. Tegaserod, while having no effect on low cholesterol fed animals, effectively abolished the potentiation of carbachol- and DMPP- evoked jejunal contractions seen with high- cholesterol fed animals. Thus, tegaserod may prevent the development of enhanced nicotinic and muscarinic neurotransmission in hypercholesterol- emic animals. The high cholesterol diet did not affect in vivo intestinal transit (measured by bolus gastric infusion of inert marker) despite the enhanced cholinergic responses of the smooth muscle. However, tegaserod treatment increased transit by 25% in hypercholesterolemic animals.

BACKGROUND:Excess cholesterol in bile and in blood is a major risk factor for the respective development of gallbladder disease and atherosclerosis. This lipid in excess negatively impacts the functioning of other smooth muscles, including the intestine. Serotonin is an important mediator of the contractile responses of the small intestine. Drugs targeting the serotonin receptor are used as prokinetic agents to manage intestinal motor disorders, in particular irritable bowel syndrome. Thus, tegaserod, acting on 5-HT4 receptor, ideally should obviate detrimental effects of excessive cholesterol on gastrointestinal smooth muscle. In this study we examined the effect of tegaserod on cholesterol-induced changes in the contractile responses of intestinal smooth muscle.METHODS:The effects of a high cholesterol (1%) diet on the in vitro contractile responses of jejunal longitudinal smooth muscle from Richardson ground squirrels to the cholinergic agonist carbachol were examined in the presence or absence of tetrodrodotoxin (TTX). Two groups of animals, fed either low (0.03%) or high cholesterol rat chow diet, were further divided into two subgroups and treated for 28 days with either vehicle or tegaserod.RESULTS:The high cholesterol diet increased, by nearly 2-fold, contractions of the jejunal longitudinal smooth muscle elicited by carbachol. These cholinergic contractions were mediated by muscarinic receptors since they were blocked by scopolamine, a muscarinic receptor antagonist, but not by the nicotinic receptor antagonist, hexamethonium. Tegaserod treatment, which did not affect cholinergic contractions of tissues from low cholesterol fed animals, abrogated the increase caused by the high cholesterol diet. With low cholesterol diet TTX enhanced carbachol-evoked contractions, whereas this action potential blocker did not affect the augmented cholinergic contractions seen with tissues from animals on the high cholesterol diet. Tegaserod-treatment removed the effects of a high cholesterol diet on neuronal muscarinic receptors, as the potentiating effect of TTX on carbachol-elicited contractions was maintained in these animals.CONCLUSION:A high cholesterol diet causes significant changes to cholinergic neurotransmission in the enteric nerves of the jejunum. The mechanisms by which these effects of cholesterol are reversed by tegaserod are unknown, but relate to removal of an inhibitory effect of cholesterol on enteric nerves.

The I-domain of αMβ2-integrin (a.k.a. CD11b/CD18, Mac-1 or CR3), binds several ligands such as ICAM- 1, IC3b and fibrinogen. CD11b also interacts with and serves as a partner for signaling-incompetent, glycosylphosphatidylinositol (GPI)-linked receptors such the FcγRIIIb receptor, CD16b. Although the partially overlapping binding sites in the I-domain for some ligands are known, those for CD16b have not been identified. Using molecular modeling techniques we identified binding sites involved in the association of CD11b and CD16b. Molecular coordinates for the I-domain of CD11b and CD16b, were obtained from 1BHO.pdb and 1FNL.pdb respectively i . As occurs in activated CD11b, the aromatic ring of F302 on the α7 loop was moved from its hydrophobic pocket into the exposed phase. This molecule was energy minimized to remove steric interference. Hydrophobic, rigid- body, in silico binding was performed with the Global Range Molecular Matching (GRAMM) program to identify amino acids participating in binding. CD11b possesses a binding site for CD16b involving the amino acids D149 and R152 on the α1 loop and F302-E303 on the α7 loop. This domain partially overlaps with the DXSXS site used by IC3b, i.e.D149. Counter binding amino acids on CD16b, L27, W42, Y56, I58 and Y69, spanned four loops in the B segment.

Endocrine regulation of the neutrophilic component of innate immunity with a particular focus on the production of reactive oxygen species (ROS) is the subject of this review. Endocrine hormones contribute to neutrophil mediated pathology in several ways either by directly activating the cells, as is the case with an angiotensin activation of NADPH oxidase on neutrophils and monocytes to contribute to atherosclerosis, or by having biphasic effects depending upon the stage of systemic inflammation, i.e. in a hyper-inflammatory phase or a hypo-inflammatory or anergic state, as seen with growth hormone. Some factors, such as a novel anti-inflammatory peptide from salivary glands, the tripeptide FEG, and hypothalamic proline-rich peptide have more subtle effects and appear to negatively regulate the priming events required for neutrophil activation. Investigations on the impact and role of endocrine hormones on neutrophil function and ROS production have contributed to the understanding of the efficacy of some medications in treating inflammation, as is the case with the angiotensin receptor blockers, and should lead to the development of novel drugs that modulate innate immune system function and the severity of an inflammatory response. Keywords: Hormones, peptides, reactive oxygen species, superoxide, leukocytes, anti-inflammatory

Background Excess cholesterol in bile and in blood is a major risk factor for the respective development of gallbladder disease and atherosclerosis. This lipid in excess negatively impacts the functioning of other smooth muscles, including the intestine. Serotonin is an important mediator of the contractile responses of the small intestine. Drugs targeting the serotonin receptor are used as prokinetic agents to manage intestinal motor disorders, in particular irritable bowel syndrome. Thus, tegaserod, acting on 5-HT4 serotonin receptor, ideally should obviate detrimental effects of excessive cholesterol on gastrointestinal smooth muscle. In this study we examined the effect of tegaserod on cholesterol-induced changes in the contractile responses of intestinal smooth muscle. Methods The effects of a cholesterol-enriched (1%) diet on the in vitro contractile responses of jejunal longitudinal smooth muscle from Richardson ground squirrels to the cholinergic agonist carbachol were examined in the presence or absence of tetrodrodotoxin (TTX). Two groups of animals, fed either low or 1% cholesterol supplemented rat chow diet, were further divided into two subgroups and treated for 28 days with either vehicle or tegaserod. Results The high cholesterol diet increased, by nearly 2-fold, contractions of the jejunal longitudinal smooth muscle elicited by carbachol. These cholinergic contractions were mediated by muscarinic receptors since they were blocked by scopolamine, a muscarinic receptor antagonist, but not by the nicotinic receptor antagonist, hexamethonium. Tegaserod treatment, which did not affect cholinergic contractions

Food allergies are generally associated with gastrointestinal upset, but in many patients systemic reactions occur. However, the systemic effects of food allergies are poorly understood in experimental animals, which also offer the opportunity to explore the actions of anti-allergic drugs. The tripeptide D-phenylalanine-D-glutamate-Glycine (feG), which potentially alleviates the symptoms of systemic anaphylactic reactions, was tested to determine if it also reduced systemic inflammatory responses provoked by a gastric allergic reaction.

We have established that decentralization (cutting sympathetic nerve trunk) of the superior cervical ganglia bilaterally reduces the magnitude of allergic inflammation in the airways of rats. The magnitude of anaphylactic and endotoxic hypotension, and of gastrointestinal inflammation was also reduced. This anti-inflammatory activity was dependent upon intact submandibular glands. Reconstitution of sialadenectomized (removal of submandibular glands) rats with soluble extracts of the submandibular glands identified two polypeptides with anti-inflammatory activities. The sequences of these polypeptides were found within a prohormone, submandibular gland rat 1 (SMR1). The C-terminal peptide TDIFEGG, has been studied extensively. Using sequential amino acid substitutions and systematic removal of C terminal or N terminal amino acids, we established that the tripeptide FEG is biologically active. Modification of FEG to the D-isomeric feG, enhances its activity in some assay systems. We postulated that feG would inhibit airways inflammation, and tested this using a model ofallergic asthma, namely the Brown Norway rat sensitized to ovalbumin (OA). Sensitized rats were challenged 14 to 21 days later with aerosolized OA. This challenge markedly increased numbers of inflammatory cells recovered from the airways after 24 hour (29×10 6 , n=23) compared to saline controls (1×10 6 , n=4). The infiltrating cells included macrophages (10×10 6 ), neutrophils (9×10 6 ) and eosinophils (9×10 6 ). Intravenous (0.25 mg/kg) or oral feG (1 mg/kg) given 30 min prior to OA significantly inhibited influx of inflammatory cells by 50 to 70%. feG reduced inflammatory cell infiltration when given 30 min before to 3 to 6 hour post allergen exposure. Oral feG reduced the numbers of macrophages, neutrophils and eosinophils. One of the mechanisms underlying the effects of feG may be its ability to inhibit PAF-induced expression of CD11b on purified human neutrophils. It is possible that feG may be useful in the treatment of allergic asthma, given either as an oral prophylactic, or as a post exposure therapeutic. The cervical sympathetic nerve trunk-submandibular gland axis of neuroendocrine regulation of inflammation may be dysfunctional in inflammatory diseases and provide opportunities for new therapeutic intervention. This axis may be sensitive to modulation by central and peripheral neural mechanisms that influence its function/dysfunction.

Submandibular gland peptide-T (SGP-T), a heptapeptide with the sequence of threonine, aspartate, isoleucine, phenylalanine, glutamate, glycine, glycine (TDIFEGG), was isolated from the submandibular glands of rats based on the ability of extracts of these glands to reduce the hypotension induced by bacterial lipopolysaccharide. SGP-T was also found to decrease the severity of the cardiovascular shock provoked by antigen administration to ovalbumin-sensitized rats. An analysis of the structure-activity relationship revealed that three amino acids, phenylalanine, glutamate, glycine (FEG), located in the carboxy terminal of SGP-T were sufficient to inhibit intestinal anaphylaxis in vitro. Interestingly, the D-isomeric form of FEG (feG) did not inhibit anaphylaxis in the in vitro assay. However, both tripeptides, FEG and feG, significantly reduced anaphylactic hypotension and intestinal anaphylaxis in vivo. SGP-T may be a prototype of a family of small peptides that modulate the immune and smooth muscle reactions to severe inflammatory stress. SGP-T preferentially inhibits cardiovascular anaphylaxis, whereas feG exhibits a high degree of selectivity for inhibiting intestinal anaphylaxis in vivo. Biomedical Reviews 1998; 9: 101-106.

A novel peptide, submandibular gland peptide-T(SGP-T), which reduces allergen-induced hypotension, wasexamined for effects on intestinal anaphylaxis.Hooded-Lister rats were sensitized to egg albumin and prepared for the measurement of in vivomyoelectric activity of the jejunum. The disruption ofmigrating myoelectric complexes (MMCs) that occurs uponintraluminal, duodenal challenge with antigen of sensitized rats was inhibited by 75% uponintravenous treatment with 100 μg/kg of SGP-T. Inaddition, SGP-T reduced the number of rats experiencinganaphylactic diarrhea and disrupted MMCs, but thepeptide did not alter antigen-provoked release of ratmast cell protease II. The mechanism of action of SGP-Tremains to be determined, but it apparently does not actdirectly on mast cells to exert its antianaphylactic action. These results emphasize that modulationof immediate hypersensitivity reactions is only one ofseveral gastrointestinal activities that are affected bygrowth factors and peptides released from salivary glands.