Effects of R-102444 and its active metabolite R-96544, selective 5-HT2A receptor antagonists, on experimental acute and chronic pancreatitis: Additional evidence for possible involvement of 5-HT2A receptors in the development of experimental pancreatitis

Post-endoscopic retrograde cholangiopancreatography pancreatitis: A systematic review for prevention and treatment

BACKGROUND

Post endoscopic retrograde cholangiopancreatography (ERCP) is comparatively complex application. Researchers has been investigated prevention of post-ERCP pancreatitis (PEP), since it has been considered to be the most common complication of ERCP. Although ERCP can lead various complications, it can also be avoided.

AIM

To study the published evidence and systematically review the literature on the prevention and treatment for PEP.

METHODS

A systematic literature review on the prevention of PEP was conducted using the electronic databases of ISI Web of Science, PubMed and Cochrane Library for relevant articles. The electronic search for the review was performed by using the search terms “Post endoscopic retrograde cholangiopancreatography pancreatitis” AND “prevention” through different criteria. The search was restricted to randomized controlled trials (RCTs) performed between January 2009 and February 2019. Duplicate studies were detected by using EndNote and deleted by the author. PRISMA checklist and flow diagram were adopted for evaluation and reporting. The reference lists of the selected papers were also scanned to find other relevant studies.

RESULTS

726 studies meeting the search criteria and 4 relevant articles found in the edited books about ERCP were identified. Duplicates and irrelevant studies were excluded by screening titles and abstracts and assessing full texts. 54 studies were evaluated for full text review. Prevention methods were categorized into three groups as (1) assessment of patient related factors; (2) pharmacoprevention; and (3) procedural techniques for prevention. Most of studies in the literature showed that young age, female gender, absence of chronic pancreatitis, suspected Sphincter of Oddi dysfunction, recurrent pancreatitis and history of previous PEP played a crucial role in posing high risks for PEP. 37 studies designed to assess the impact of 24 different pharmacologic agents to reduce the development of PEP delivered through various administration methods were reviewed. Nonsteroidal anti-inflammatory drugs are widely used to reduce risks for PEP. Rectal administration of indomethacin immediately prior to or after ERCP in all patients is recommended by European Society for Gastrointestinal Endoscopy guidelines to prevent the development of PEP. The majority of the studies reviewed revealed that rectally administered indomethacin had efficacy to prevent PEP. Results of the other studies on the other pharmacological interventions had both controversial and promising results. Thirteen studies conducted to evaluate the efficacy of 4 distinct procedural techniques to prevent the development of PEP were reviewed. Pancreatic Stent Placement has been frequently used in this sense and has potent and promising benefits in the prevention of PEP. Studies on the other procedural techniques have had inconsistent results.

CONCLUSION

Prevention of PEP involves multifactorial aspects, including assessment of patients with high risk factors for alternative therapeutic and diagnostic techniques, administration of pharmacological agents and procedural techniques with highly precise results in the literature.

Serotonin in the gut: Blessing or a curse

Serotonin (5-hydroxytryptamine or 5-HT) once most extensively studied as a neurotransmitter of the central nervous system, is seen to be predominantly secreted in the gut. About 95% of 5-HT is estimated to be found in gut mainly within the enterochromaffin cells whereas about 5% is found in the brain. 5-HT is an important enteric signaling molecule and is well known for playing a key role in sensory-motor and secretory functions in the gut. In recent times, studies uncovering various new functions of gut-derived 5-HT indicate that many more are yet to be discovered in coming days. Recent studies revealed that 5-HT plays a pivotal role in immune cell activation and generation/perpetuation of inflammation in the gut. In addition to its various roles in the gut, there are now emerging evidences that suggest an important role of gut-derived 5-HT in other biological processes beyond the gut, such as bone remodeling and metabolic homeostasis. This review focuses to briefly summarize the accumulated and newly updated role of 5-HT in the maintenance of normal gut physiology and in the pathogenesis of inflammation in the gut. The collected information about this multifaceted signaling molecule may aid in distinguishing its good and bad effects which may lead to the development of novel strategies to overcome the unwanted effect, such as in inflammatory bowel disease.

Tryptophan hydroxylase 1 and 5-HT7 receptor preferentially expressed in triple-negative breast cancer promote cancer progression through autocrine serotonin signaling

BACKGROUND

Triple-negative breast cancer (TNBC) has a high risk of relapse and there are few chemotherapy options. Although 5-hydroxytryptamine (5-HT, serotonin) signaling pathways have been suggested as potential targets for anti-cancer drug development, the mechanism responsible for the action of 5-HT in TNBC remains unknown.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to measure mRNA and protein levels, respectively. Cell proliferation was measured using CellTiter 96 Aqueous One Solution. siRNA transfection was used to assess involvement of genes in cancer invasion, which were identified by Matrigel transwell invasion assay. Levels of 5-HT and vascular endothelial growth factor (VEGF) were measured using ELISA kits. Chick chorioallantoic membrane (CAM) assay and mouse tumor model were used to investigate the in vivo effects of SB269970, a 5-HT₇ receptor antagonist, and BJ-1113, a novel synthetic compound.

RESULTS

TNBC cell lines (MDA-MB-231, HCC-1395, and Hs578T) expressed higher levels of tryptophan hydroxylase 1 (TPH1) than hormone-responsive breast cancer cell lines (MCF-7 and T47D). In MDA-MB-231 cells, 5-HT promoted invasion and proliferation via 5-HT₇ receptor, and interestingly, the stimulatory effect of 5-HT on MDA-MB-231 cell invasion was stronger than its effect on proliferation. Likewise, downstream signaling pathways of 5-HT₇ differed during invasion and proliferation, that is, Gα-activated cAMP and Gβγ-activated kinase signaling during invasion, and Gβγ-activated PI3K/Akt signaling during proliferation. Also, 5-HT increased the protein expressions of TPH1 and VEGF in MDA-MB-231 cells. These results provide insight of the stimulatory effect of 5-HT on breast cancer progression; 5-HT was found to act more strongly during the first stage of metastasis (during invasion and migration) than during the later proliferative phase after local invasion. Interestingly, these actions of 5-HT were inhibited by BJ-1113, a 6-amino-2,4,5-trimethylpyridin-3-ol analog. BJ-1113 blocked intracellular signaling pathways initiated by 5-HT₇ receptor activation, and exhibited anti-proliferative and anti-invasive activities against MDA-MB-231 cells. Furthermore, the inhibitory effect of BJ-1113 against MDA-MB-231 tumor growth was greater than that of SB269970, a 5-HT₇ receptor antagonist.

CONCLUSIONS

5-HT₇ receptor which mediates 5-HT-induced cancer progression is a potential therapeutic target in TNBC, and BJ-1113 offers a novel scaffold for the development of anti-cancer agents against TNBC.

The results of the Tokyo trial of prevention of post-ERCP pancreatitis with risperidone (Tokyo P3R): a multicenter, randomized, phase II, non-placebo-controlled trial

BACKGROUND

A previous study suggested that ulinastatin effectively prevented post-ERCP pancreatitis (PEP) and hyperenzymemia (PEH) in patients at average risk. In experimental models, risperidone, a selective serotonin 2A antagonist, ameliorated acute pancreatitis. We assessed the effect of risperidone combined with ulinastatin for the prevention of PEP in high-risk patients.

METHODS

In a multicenter, randomized, controlled, phase II trial, patients undergoing therapeutic ERCP were randomly assigned to receive ulinastatin (150000 U) with or without risperidone (1 mg). A risperidone tablet was taken orally 30-60 min before ERCP and ulinastatin was administered intravenously for 10 min immediately prior to ERCP. The primary end point was the incidence of PEP; secondary end points were PEH severity and enzyme levels (amylase, pancreatic amylase, lipase).

RESULTS

A total of 226 patients (113 per group) were included in the study. Six patients in the risperidone + ulinastatin group and ten patients in the ulinastatin group developed pancreatitis (5.3 vs. 8.8 %, p = 0.438). The incidence of moderate/severe PEP was lower in the risperidone + ulinastatin group (1.8 %) than in the ulinastatin group (4.4 %), but this difference was not significant. Although the incidence of PEH did not differ significantly, post-ERCP levels of all pancreatic enzymes were significantly lower in the risperidone + ulinastatin group.

CONCLUSIONS

Prophylactic oral risperidone administration in combination with ulinastatin did not reduce the incidence and severity of PEP in high-risk patients as compared with ulinastatin alone. However, risperidone showed an additive effect with ulinastatin, reducing serum pancreatic enzyme levels.

Altered serotonin physiology in human breast cancers favors paradoxical growth and cell survival

Introduction

The breast microenvironment can either retard or accelerate the events associated with progression of latent cancers. However, the actions of local physiological mediators in the context of breast cancers are poorly understood. Serotonin (5-HT) is a critical local regulator of epithelial homeostasis in the breast and other organs. Herein, we report complex alterations in the intrinsic mammary gland serotonin system of human breast cancers.

Methods

Serotonin biosynthetic capacity was analyzed in human breast tumor tissue microarrays using immunohistochemistry for tryptophan hydroxylase 1 (TPH1). Serotonin receptors (5-HT1-7) were analyzed in human breast tumors using the Oncomine database. Serotonin receptor expression, signal transduction, and 5-HT effects on breast cancer cell phenotype were compared in non-transformed and transformed human breast cells.

Results

In the context of the normal mammary gland, 5-HT acts as a physiological regulator of lactation and involution, in part by favoring growth arrest and cell death. This tightly regulated 5-HT system is subverted in multiple ways in human breast cancers. Specifically, TPH1 expression undergoes a non-linear change during progression, with increased expression during malignant progression. Correspondingly, the tightly regulated pattern of 5-HT receptors becomes dysregulated in human breast cancer cells, resulting in both ectopic expression of some isoforms and suppression of others. The receptor expression change is accompanied by altered downstream signaling of 5-HT receptors in human breast cancer cells, resulting in resistance to 5-HT-induced apoptosis, and stimulated proliferation.

Conclusions

Our data constitutes the first report of direct involvement of 5-HT in human breast cancer. Increased 5-HT biosynthetic capacity accompanied by multiple changes in 5-HT receptor expression and signaling favor malignant progression of human breast cancer cells (for example, stimulated proliferation, inappropriate cell survival). This occurs through uncoupling of serotonin from the homeostatic regulatory mechanisms of the normal mammary epithelium. The findings open a new avenue for identification of diagnostic and prognostic markers, and valuable new therapeutic targets for managing breast cancer.

Risperidone attenuates local and systemic inflammatory responses to ameliorate diet-induced severe necrotic pancreatitis in mice: it may provide a new therapy for acute pancreatitis

In a previous article, we showed that a potent serotonin-, 5-hydroxytryptamine-2A (5-HT(2A)) antagonist, risperidone, ameliorated cerulein-induced edematous pancreatitis in mice. In the present article, young female mice were fed a choline-deficient, ethionine-supplemented diet. All of the mice developed severe necrotic pancreatitis, and approximately 50% of them died within 4 days. Serum levels of proinflammatory interleukin (IL)-6 significantly increased on day 3 and returned toward the control on day 4 of choline-deficient ethionine-supplemented (CDE) diet treatment. The time course of IL-6 levels paralleled those of plasma amylase and lipase activities. On the other hand, platelet counts significantly decreased on day 3, and the change became more marked on day 4, coinciding with mortality and histological alterations of the pancreas (edema, inflammatory cell infiltration, necrosis). Preceding these changes, plasma levels of 5-hydroxyindoleacetic acid (5-HIAA) increased on feeding a CDE diet to reach a peak on day 3 and returned toward the control on day 4. Risperidone (0.1-3.2 mg/kg twice a day) hardly affected the 5-HIAA levels but dose-dependently attenuated the serum IL-6 levels, plasma amylase/lipase levels, platelet counts, histological alterations, and mortality of diet-induced pancreatitis mice. These results are discussed in relation to the pathogenesis of acute pancreatitis. Thus, we speculate that acinar cell injury triggers local inflammatory reactions and, if coincided with enhanced IL-6 release, leads to a systemic inflammatory response syndrome, which is responsible for the mortality. In addition, it is suggested that diet-induced 5-HT release and 5-HT(2A) receptor activation are involved in this whole process of pancreatitis development. Risperidone may provide a new therapy for the disease.

Pathophysiological role of platelets and platelet system in acute pancreatitis

The most successful approach for restoring normal long-term glucose homeostasis in type I diabetes mellitus is whole-organ pancreas transplantation. Graft pancreatitis is observed in up to 20% of patients and may lead to loss of the transplanted organ. Several pathophysiological events have been implicated in this form of pancreatitis. The most important cause of early graft pancreatitis is ischemia/reperfusion (I/R)-related disturbance of microvascular perfusion with subsequent hypoxic tissue damage. Recently, considerable evidence accumulated that, among a variety of other pathophysiological events, the activation of platelets can contribute to I/R injury in the course of acute pancreatitis experimentally and clinically. This review summarizes the events affecting platelet function and, therefore, pancreatic microcirculation leading to acute pancreatitis. Therapeutic approaches and own results are presented.

Possible involvement of endogenous 5-HT in aggravation of cerulein-induced acute pancreatitis in mice

The aim of the present study was to elucidate the pathogenic role of endogenous 5-HT in pancreatitis. Injections of cerulein at hourly intervals caused edematous pancreatitis in mice characterized by hyperenzymemia and histological alterations. While the cerulein-induced hyperenzymemia was attenuated in mice pretreated with p-CPA, a 5-HT depletor, it was exaggerated by the preferential 5-HT2A agonist (DOI), but not by the preferential 5-HT2B agonist (BW723C86) or the preferential 5-HT2C agonist (mCPP). Selective 5-HT2A antagonists (risperidone, spiperone, ketanserin, AMI-193, and MDL 11,939) dose-dependently attenuated the hyperenzymemia; and their potency order, excepting that of ketanserin which has considerable affinity at the 5-HT2C receptor as well, paralleled their reported pKi values at the 5-HT2A receptor. Selective 5-HT2B (SB204741) and 5-HT2C (SB242084) antagonists hardly affected the hyperenzymemia. Although the non-selective 5-HT2A/2B/2C antagonists (metergoline, ritanserin, and methysergide) dose-dependently attenuated the hyperenzymemia, they were relatively less potent compared to their high pKi values at the 5-HT2A receptor. In another set of experiments, risperidone, but not SB204741 and SB242084, dose-dependently reversed the cerulein-induced histological alteration of the pancreas (inflammatory cell infiltration). These results suggest that endogenously released 5-HT activates 5-HT2A receptors to aggravate cerulein-induced pancreatitis. We propose that selective 5-HT2A antagonists may provide a new therapy for acute pancreatitis.

Coagulation, platelets, and acute pancreatitis

Acute pancreatitis generates a complex cascade of immunological events that affect the pathogenesis and the progression of this disease. Several inflammatory mediators seem to play a critical role in the pathogenesis of pancreatitis and the subsequent inflammatory response. In turn, these mediators can influence hemostasis. Coagulation abnormalities occur in acute pancreatitis and are related to its severity. The contribution of blood platelets in the disturbed hemostasis in acute pancreatitis, although extensively studied, remains obscure. This article reviews the local and systemic implications of hemostatic abnormalities during acute pancreatitis. Furthermore, we discuss the prognostic value and the potential therapeutic implications of platelet activation and other hemostatic variables.

Acute pancreatitis: animal models and recent advances in basic research

Acute pancreatitis (AP) is characterized by edema, acinar cell necrosis, hemorrhage, and severe inflammation of the pancreas. Patients with AP present with elevated blood and urine levels of pancreatic digestive enzymes, such as amylase and lipase. Severe AP may lead to systemic inflammatory response syndrome and multiorgan dysfunction syndrome, which account for the high mortality rate of AP. Although most (>80%) cases of AP are associated with gallstones and alcoholism, some are idiopathic. Although the pathogenesis of AP has not yet been elucidated, a common feature is the premature activation of trypsinogen within pancreatic tissues, which triggers autodigestion of the gland. Recent advances in basic research suggest that etiologic factors including cyclooxygenase-2, substance P, and angiotensin II may have novel roles in this disease. Basic research data obtained thus far have been based on animal models of AP ranging from mild edematous pancreatitis to severe necrotizing pancreatitis. In view of this, an adequate selection of experimental animal models is of paramount importance. Notwithstanding these animal models, it should be emphasized that none of these models mimic the clinical situation where varying degrees of severity usually occur. In this review, commonly used animal models of AP will be critically evaluated. A discussion of recent advances in our knowledge about AP risk factors is also included.

Chronic pancreatitis

PURPOSE OF REVIEW

As in our previous reviews, we endeavor to review important new observations in chronic pancreatitis made in the past year. Topics recently reviewed were truncated to accommodate a surge in publications on clinical aspects of chronic pancreatitis, which contained new observations or insights into new or old concepts.

RECENT FINDINGS

Cystic fibrosis carriers have been found to be at increased risk of pancreatitis. Autoimmune pancreatitis may belong to a multiorgan immunoglobulin G4-related autoimmune disease, and the natural history of chronic pancreatitis differs among the etiologies. Diffusion-weighted magnetic resonance imaging improves upon previous methodologies for diagnosing reduced pancreatic exocrine secretion, and fecal elastase-1 has been found to be a poor test for diagnosing pancreatic malabsorption. Visceral hyperalgesia or heightened central pain perception may contribute to pain in chronic pancreatitis. Instruments are evolving to assess quality of life in chronic pancreatitis, and fibrolytic agents have been found to have therapeutic promise.

SUMMARY

Researchers this past year have further characterized genetic, molecular and clinical aspects of chronic pancreatitis. Advancing the understanding of fibrogenesis, mechanisms of exocrine insufficiency, calcification, and pain and continuing development/modification of diagnostic tests should lead to improved prevention, detection and treatment of the condition. More accurate quantification of outcomes is critical for translating potential therapies from bench to bedside.