Emerging drugs for functional dyspepsia

Evaluation of the Potential Protective Effects of Lactobacillus Strains against Helicobacter pylori Infection: A Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND

The beneficial effects of probiotic supplementation standard antibiotic therapies for Helicobacter pylori infection have been verified, but the ability of probiotic monotherapy to eradicate H. pylori remains unclear.

AIM

To evaluate the accuracy and efficacy of specific Lactobacillus strains against H. pylori infection.

METHODS

Seventy-eight patients with H. pylori infection were treated with strain L. crispatus G14-5M (L. crispatus CCFM1118) or L. helveticus M2-09-R02-S146 (L. helveticus CCFM1121) or L. plantarum CCFM8610 at a dose of 2 g twice daily for one month. ¹⁴C-urea breath test, the gastrointestinal symptom rating scale, serum pepsinogen concentrations, and serum cytokine concentrations of patients were measured at baseline and end-of-trial to analyze the effect of the Lactobacillus strains in eradicating H. pylori infection and reducing gastrointestinal discomfort in patients. In addition, the composition and abundance of the intestinal microbiota of patients were also measured at end-of-trial.

RESULTS

The ¹⁴C-urea breath test value of the three Lactobacillus treatment groups had decreased significantly, and the eradication rate of H. pylori had increased by the end of the trial. In particular, the eradication rate in the G14-5M treatment group was significantly higher than the placebo group (70.59% vs. 15.38%, P=0.0039), indicating that one-month administration of the G14-5M regimen was sufficient to eradicate H. pylori infection. The ingestion of Lactobacillus strains also ameliorated the gastrointestinal symptom rating scale scores, and the serum interleukin-8 concentrations of H. pylori-infected patients appeared to modulate the gut microbiota of patients. However, none of the Lactobacillus strains had a significant effect on general blood physiological characteristics, serum tumor necrosis factor α concentrations, or serum pepsinogen concentrations in the patients.

CONCLUSION

Three Lactobacillus strains significantly alleviate the gastrointestinal discomfort and the gastric inflammatory response of H. pylori-infected patients. The activity of probiotics in eradicating H. pyloriinfection may be species/strain specific.

The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions

Functional gastrointestinal disorders (FGIDs), characterized by chronic abdominal complaints without a structural or biochemical cause, are common diseases that are frequently encountered by specialists in internal medicine. Collectively, irritable bowel syndrome (IBS) and functional dyspepsia are estimated to affect up to 22% of the population, and are often associated with additional somatic and pain complaints, all without an obvious structural source [1,2]. An appreciation of the current understanding of the mechanistic basis for these disorders is key to developing treatment goals and optimization of patient management strategies. In recent years, the brain-gut axis increasingly has been recognized as a central factor in the experience of functional abdominal pain disorders, including the most recent Rome IV guidelines which identify FGIDs as disorders of gut-brain interaction [3]. The brain-gut axis (BGA), simply defined, is a complex network of bidirectional communication between the central and enteric nervous systems. This axis broadly includes all the systems involved with communication between the GI tract and central nervous system (CNS), with principle inputs into this network occurring between the CNS, enteric nervous system (ENS), and autonomic nervous systems (ANS), but also includes interfaces with numerous other factors, including endocrine hormones and immune effector cells as well as interactions with the gut microbiota. Perturbances to this system have been found to play a critical role in the development of visceral hypersensitivity, bowel dysregulation, and mood. This review will summarize the principle processes involved in the neurologic and biologic function of the brain-gut axis, our current understanding of its role in functional GI disorders, and potential targets for therapeutic intervention.

Stereoelectronic Effects in Ligand Design: Enantioselective Rhodium-Catalyzed Hydrogenation of Aliphatic Cyclic Tetrasubstituted Enamides and Concise Synthesis of (R)-Tofacitinib

We herein report the development of a conformationally defined, electron-rich, C₂ -symmetric, P-chiral bisphosphorus ligand, ArcPhos, by taking advantage of stereoelectronic effects in ligand design. With the Rh-ArcPhos catalyst, excellent enantioselectivities and unprecedentedly high turnovers (TON up to 10 000) were achieved in the asymmetric hydrogenation of aliphatic carbocyclic and heterocyclic tetrasubstituted enamides, to generate a series of chiral cis-2-alkyl-substituted carbocyclic and heterocyclic amine derivatives in excellent enantiomeric ratios. This method also enabled an efficient and practical synthesis of the Janus kinase inhibitor (R)-tofacitinib.

Two ghrelin receptor agonists for adults with malnutrition: a systematic review and meta-analysis

Background

Ghrelin receptor agonists have been established to be important in ameliorating the nutritional conditions in patients with malnutrition. However, some studies have reported inconsistent results. We aimed to coalesce the available evidence on the efficacy of ghrelin receptor agonists for the treatment of malnutrition.

Methods

We searched PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE for relevant articles published through March 2016. Studies comparing the efficacy of ghrelin receptor agonists versus placebo in malnourished patients were eligible for inclusion.

Results

A total of 12 studies involving 1377 patients were included. Compared with placebo, ghrelin receptor agonists could increase the energy intake (standard mean difference [SMD] 2.67, 95% confidence interval [CI] 1.48 to 3.85, P < 0.001), lean body mass (weighted mean difference [WMD] 0.25 kg, 95% CI 0.07 to 0.42, P = 0.006), fat mass (WMD 0.92 kg, 95% CI 0.05 to 1.8, P = 0.038), and grip strength (WMD 0.31 kg, 95% CI 0.207 to 0.414, P < 0.001) of patients with malnutrition.

Conclusion

Our analysis indicated that ghrelin receptor agonists could improve the poor nutritional state of malnourished patients by increasing their energy intake, ameliorating their irregular body composition and improving their grip strength. However, these results might be less conclusive due to the limited sample sizes and one potential publication that has not been released.

Dyspepsia in the community: value of a community-based mailed survey to identify potential participants for a randomized clinical trial

OBJECTIVE

To assess the usefulness of a community-based mailed survey to identify participants with functional dyspepsia (FD) for a clinical trial.

MATERIAL AND METHODS

In 2008, a valid self-report questionnaire of gastrointestinal symptoms required for diagnosis of FD was mailed to randomly selected cohorts of Olmsted County, Minnesota, residents. From survey responses (54%), FD cases and controls were identified. Phone calls were completed in 2010 and 2011 to 54% of respondents offering participation to those meeting criteria.

RESULTS

Of 937 people identified from the survey, 189 cases and 265 controls were contacted by phone using four questions similar to the written survey resulting in a moderate level of agreement (Kappa 0.43, 95% CI: 0.35- 0.51; p = 0.11). The proportion reporting FD symptoms by survey was 42%, while the proportion by phone was 38%. Comparing classification of cases and controls, 118 (62%) survey cases had dyspepsia symptoms on phone screening while 53 (20%) of the survey controls reported FD symptoms. Of 171 who had symptoms, 60 (35%) declined, 33 (19%) were over study age limit, 24 (14%) had inadequate symptom levels and 36 (21%) had comorbidities. Of survey respondents contacted, six (3%) people were enrolled with two screen fails resulting in four (1%) randomized.

CONCLUSION

Agreement between survey and phone questions was modest. Classifications between case and control changed. People eligible and willing to participate were a fraction of people reporting symptoms. People participating in clinical trials do not broadly represent those in the population.

Medical treatment of functional dyspepsia

Functional dyspepsia (FD) is a condition in which upper abdominal symptoms, such as epigastralgia, postprandial discomfort, and bloating, occur in the absence of any organic or metabolic disease that could explain the symptoms. The prevalence of FD is increasing, presumably because of an increasingly stressful environment, as well as overlap with other motility disorders such as gastroesophageal reflux diseases and irritable bowel syndrome. Numerous studies have attempted to determine the pathophysiological mechanisms of FD and establish effective FD treatment, with little success. Several therapeutic options have been explored, including Helicobacter pylori eradication, proton pump inhibitors, prokinetic agents, anti-depressant and anxiolytic agents, and acotiamide, a recent emerging drug. Through the many trials evaluating the efficacy of drugs for FD treatment, we found that it is necessary to treat according to the symptoms of FD and to use a combination of therapeutic options. Additional well-designed, prospective studies are needed to confirm the management of FD.

The effects of 5-hydroxytryptamine1a receptor agonist, buspirone on the gastric fundus accommodation in an animal model using guinea pigs

BACKGROUND

To date, few animal experiments have been conducted to examine the effects and mechanisms of buspirone in inducing the relaxation of the gastric fundus. The aim of this study is to examine the effects and mechanisms of buspirone, 5-HT(1a) receptor agonist, in the accommodation of gastric fundus muscle in an animal experimental model using guinea pigs.

METHODS

In the current study, we performed an immunohistochemistry for 5-HT(1a) receptors in the tissue samples collected from the stomach of guinea pig, an ex vivo experiment to examine the electrical field stimulation (EFS)-induced relaxation of the circular muscle in the gastric fundus in guinea pigs and an in vivo experiment to measure the intragastric pressure through the insertion of the balloon catheter in the fundus.

KEY RESULTS

Immunohistochemical stains for 5-HT(1a) receptor could confirm the expression of 5-HT(1a) receptor in guinea pig stomach. There was a significant dose-dependent inhibition of the EFS-induced relaxation of fundic muscle strips following the treatment with WAY-100635 (5-HT(1a) antagonist), but this was significantly improved following the treatment with buspirone. An in vivo measurement of the gastric fundic tone showed that there was a significant decrease in the intragastric pressure at same volume by pretreatment with buspirone as compared with the vehicle control, but this could be prevented with the treatment with WAY-100635.

CONCLUSIONS & INFERENCES

Based on our results, it can be concluded that buspirone is effective in relaxing the gastric fundus via 5-HT(1a) receptor pathway in both in vitro and in vivo experimental models using guinea pigs.

Rumination syndrome: a review of current concepts and treatments

Rumination is a normal and common phenomenon among ruminant animals; but in humans, it is always regarded as symptom indicative of abnormal function of the upper gastrointestinal tract, and understanding of the mechanisms explaining this event are still evolving. Learning-based theories, organic factors such as gastroesophageal reflux disease and psychological disturbances (eg, depression, anxiety) and the role of life stresses have been postulated as potential mechanisms of rumination. In this review, we take the approach that rumination syndrome is a distinct and discrete functional gastroduodenal disorder. We review current concepts of the pathophysiology of this entity and diagnostic approaches, then detail the treatment paradigms that have been pursued in rumination syndrome in adults. Patients with rumination syndrome have a very distinct set of symptoms. It was focused on the immediate postprandial period, but recently, there is an awareness of an expanding spectrum of the clinical presentation. This includes the concept of "conditioned vomiting" occurring in the setting of delayed gastric emptying (gastroparesis). Physicians' awareness of rumination syndrome is essential in the diagnosis and management of this disorder. Stress and psychological aspects in rumination syndrome are invariably in the background and have to be addressed. The crucial steps in the treatment strategy for rumination syndrome rely on reassurance, education and a physiologic explanation to the patient and family that this is not a "disease," followed by behavioral and relaxation programs and addressing stress factors.

Preclinical gastrointestinal prokinetic efficacy and endocrine effects of the ghrelin mimetic RM-131

AIMS

The 28 amino acid hormone ghrelin, the natural ligand for the growth hormone secretagogue, or ghrelin receptor (GHR), has diverse physiological functions, including a possible role as a gastrointestinal prokinetic. The synthetic ghrelin mimetic RM-131 is in Phase II clinical trials for treatment of diabetic gastroparesis and other gastrointestinal (GI) disorders. We aimed to determine the relative potency of RM-131, when compared to other GI ghrelin mimetics, to predict efficacy and determine the role of RM-131 in models of inflammatory bowel disease.

MAIN METHODS

We evaluated and compared ghrelin, RM-131 and other synthetic ghrelin mimetics for their prokinetic potency in models of gastrointestinal disorders in the rat and we evaluated the endocrine (rats and dogs) and anti-inflammatory effects (mice) of the ghrelin mimetic RM-131.

KEY FINDINGS

The pentapeptide RM-131 increased gastric emptying in rodent models of ileus. RM-131 is about 100-fold more potent than human ghrelin and is 600 to 1800-fold more potent, when compared to several investigational ghrelin mimetics tested in clinical trials. RM-131 has anti-inflammatory effects and significantly increases survival and reduces macroscopic markers of tissue damage in a TNBS model of inflammatory bowel disease. RM-131 treatment shows a transient increase in growth hormone levels in Beagle dogs and rats, returning to baseline upon chronic treatment. Significant effects on glucose and insulin are not observed in chronic studies.

SIGNIFICANCE

RM-131's potency, efficacy and endocrine profile, are promising attributes for the treatment of diverse functional gastrointestinal disorders in humans.

DA-9701: A New Multi-Acting Drug for the Treatment of Functional Dyspepsia

Motilitone^® (DA-9701) is a new herbal drug that was launched for the treatment of functional dyspepsia in December 2011 in Korea. The heterogeneous symptom pattern and multiple causes of functional dyspepsia have resulted in multiple drug target strategies for its treatment. DA-9701, a compound consisting of a combination of Corydalis Tuber and Pharbitidis Semen, has being developed for treatment of functional dyspepsia. It has multiple mechanisms of action such as fundus relaxation, visceral analgesia, and prokinetic effects. Furthermore, it was found to significantly enhance meal-induced gastric accommodation and increase gastric compliance in dogs. DA-9701 also showed an analgesic effect in rats with colorectal distension induced visceral hypersensitivity and an antinociceptive effect in beagle dogs with gastric distension-induced nociception. The pharmacological effects of DA-9701 also include conventional effects, such as enhanced gastric emptying and gastrointestinal transit. The safety profi le of DA-9701 is also preferable to that of other treatments.

Neurochemical mechanisms and pharmacologic strategies in managing nausea and vomiting related to cyclic vomiting syndrome and other gastrointestinal disorders

Nausea and vomiting are common gastrointestinal complaints which could be triggered by stimuli in both the peripheral and central nervous systems. They may be considered as defense mechanisms when threatening toxins/agents enter the gastrointestinal tract or there is excessive retention of gastrointestinal contents due to obstruction. The pathophysiology of nausea and vomiting is complex and much still remains unknown. Therefore, treatments are restricted or ineffective in many cases. Nausea and vomiting with functional etiologies including cyclic vomiting syndrome are challenging in gastroenterology. In this article, we review potential pathways, neurochemical transmitters, and their receptors which are possibly involved in the pathophysiology of nausea and vomiting including the entity cyclic vomiting syndrome.

Recent advances in the pathophysiology and treatment of gastroparesis

Gastroparesis is a clinical disorder characterized by upper gastrointestinal symptoms related with delayed gastric emptying of solids and liquids in the absence of mechanical obstruction. Diabetes mellitus has been the most common cause of gastroparesis and idiopathic gastroparesis also accounts for a third of all chronic cases. The most important mechanisms of gastroparesis, as understood to date, are loss of expression of neuronal nitric oxide synthase and loss of the interstitial cells of Cajal. However, the pathogenesis of gastroparesis is poorly understood. There have been several studies on specific molecules related to the pathogenesis of gastroparesis. Additionally, the Gastroparesis Clinical Research Consortium of the National Institutes of Health has achieved several promising results regarding the pathophysiology of gastroparesis. As the progress in the pathophysiology of gastroparesis has been made, a promising new drug therapy has been found. The pathophysiology and drug therapy of gastroparesis are focused in this review. Until now, the real-world medication options for treatment of gastroparesis are limited. However, it is expected to be substantially improved as the pathophysiology of gastroparesis is elucidated.

Acotiamide, a novel gastroprokinetic for the treatment of patients with functional dyspepsia: postprandial distress syndrome

Functional dyspepsia (FD) is a highly prevalent condition with major socioeconomic and healthcare impact. To date, no pharmacological treatment for FD has been approved. The Rome consensus proposed to subdivide FD into postprandial distress syndrome (PDS), characterized by meal-related symptoms and epigastric pain syndrome, characterized by pain and burning. Acotiamide (Z-338 or YM443) is a new drug, developed for the treatment of FD. Acotiamide enhances acetylcholine release from enteric neurons through muscarinic receptor antagonism and acetycholinesterase inhibition, thereby enhancing gastric emptying and gastric accommodation. Acotiamide was evaluated in FD in clinical studies in Europe, Japan and the USA, beneficial effects were observed for the PDS symptoms of postprandial fullness and early satiation, with a dose of 100 mg three-times a day. A 4-week placebo-controlled Phase III study in PDS patients in Japan confirmed efficacy of acotiamide in relieving postprandial fullness, early satiation and upper abdominal bloating.

Dyspepsia: organic versus functional

Dyspepsia is the medical term for difficult digestion. It consists of various symptoms in the upper abdomen, such as fullness, discomfort, early satiation, bloating, heartburn, belching, nausea, vomiting, or pain. The prevalence of dyspepsia in the western world is approximately 20% to 25%. Dyspepsia can be divided into 2 main categories: "organic" and "functional dyspepsia" (FD). Organic causes of dyspepsia are peptic ulcer, gastroesophageal reflux disease, gastric or esophageal cancer, pancreatic or biliary disorders, intolerance to food or drugs, and other infectious or systemic diseases. Pathophysiological mechanisms underlying FD are delayed gastric emptying, impaired gastric accommodation to a meal, hypersensitivity to gastric distension, altered duodenal sensitivity to lipids or acids, altered antroduodenojenunal motility and gastric electrical rhythm, unsuppressed postprandial phasic contractility in the proximal stomach, and autonomic nervous system-central nervous system dysregulation. Pathogenetic factors in FD are genetic predisposition, infection from Helicobacter pylori or other organisms, inflammation, and psychosocial factors. Diagnostic evaluation of dyspepsia includes upper gastrointestinal endoscopy, abdominal ultrasonography, gastric emptying testing (scintigraphy, breath test, ultrasonography, or magnetic resonance imaging), and gastric accommodation evaluation (magnetic resonance imaging, ultrasound, single-photon emission computed tomography, and barostat). Antroduodenal manometry can be used for the assessment of the myoelectrical activity of the stomach, whereas sensory function can be evaluated with the barostat, tensostat, and satiety test. Management of FD includes general measures, acid-suppressive drugs, eradication of H. pylori, prokinetic agents, fundus-relaxing drugs, antidepressants, and psychological interventions. This review presents an update on the diagnosis of patients presenting with dyspepsia, with an emphasis on the pathophysiological and pathogenetic mechanisms of FD and the differential diagnosis with organic causes of dyspepsia. The management of uninvestigated and FD, as well as the established and new pharmaceutical agents, is also discussed.

Prokinetic effect of a standardized yarrow (Achillea millefolium) extract and its constituent choline: studies in the mouse and human stomach

BACKGROUND

Functional dyspepsia (FD) is a highly prevalent gastrointestinal disorder characterized by alterations in gastric motility. Yarrow (Achillea millefolium L., Fam Asteraceae) preparations are traditional remedies used to treat dyspeptic complaints. Herein, we investigated the effect of a standardized dry water extract obtained from A. millefolium flowering tops (AME) on gastric motility.

METHODS

The effect of AME on motility was evaluated on the resting tone of the isolated gastric antrum and on gastric emptying in vivo (phenol red meal method) both in control mice and in the model of cancer chemotherapy (cisplatin)-induced gastric abnormalities.

KEY RESULTS

The AME contracted mouse and human gastric strips and this action was unaffected by hexamethonium and tetrodotoxin, but strongly reduced by atropine. Among various chemical ingredients in yarrow, choline, but not the flavonoids rutin and apigenin, mimicked the action of AME. Furthermore, AME deprived of choline did not exert a contractile effect. In vivo, AME stimulated gastric emptying both in control and in cisplatin-treated mice, being more active in pathological states.

CONCLUSIONS & INFERENCES

It is concluded that (i) AME exerts a direct spasmogenic effect on gastric antrum; (ii) choline is the chemical ingredient responsible of such effect; (iii) the prokinetic effect of AME observed in vivo could provide the pharmacological basis underlying its traditional use in the treatment of dyspepsia.

Functional dyspepsia

PURPOSE OF REVIEW

This review summarizes the recent progress in the epidemiology, pathophysiology and treatment of functional dyspepsia.

RECENT FINDINGS

Epidemiological, pathophysiological and therapeutic studies continue to examine the Rome III-proposed subdivision of functional dyspepsia into epigastric pain syndrome and postprandial distress syndrome. Although epidemiological studies support the subdivision, studies in patient samples show major overlap. Several studies identified overlapping functional disorders and psychosocial comorbidity as major contributors to the severity of functional dyspepsia and its impact on quality of life. Central processing of visceral stimuli, and its role in the pathogenesis of functional dyspepsia, as well as low-grade inflammation in the duodenum are important emerging topics in pathophysiology research. Therapeutic studies have reported on prokinetic and fundus-relaxing drugs. Acotiamide is a first-in-class drug with both prokinetic and fundus-relaxing properties that was evaluated in the recent phase 2 and phase 3 trials in functional dyspepsia.

SUMMARY

There is gradual progress in our understanding of the symptom pattern, impact and pathophysiology of functional dyspepsia. The areas of recent advances including the recognition of low-grade duodenal inflammation, central nervous system processing and the exploration of novel pharmacotherapeutic approaches are summarized in this review.