Erythromycin in the short- and long-term control of dyspepsia symptoms in patients with gastroparesis

Management of Gastrointestinal Symptoms in Parkinson's Disease: A Comprehensive Review of Clinical Presentation, Workup, and Treatment

Gastrointestinal symptoms in Parkinson's disease (PD) are among the most prevalent and debilitating of complications and present unique diagnostic and management challenges. Patients with PD commonly experience dysphagia, nausea, bloating, and constipation related to pathologic involvement of the enteric nervous system. In turn, gastrointestinal complications may impact motor fluctuations and the efficacy of levodopa therapy. This review will explore the common gastrointestinal manifestations of PD with an emphasis on clinical presentation, workup, and treatment strategies.

2023 update on the clinical management of gastroparesis

INTRODUCTION

Gastroparesis is characterized by symptoms suggesting gastric retention of food and objective evidence of delayed gastric emptying in the absence of a mechanical obstruction. Nausea, vomiting, early satiety, and postprandial fullness are the classic symptoms of gastroparesis. Gastroparesis is increasingly encountered by physicians. There are several recognized etiologies of gastroparesis, including diabetic, post-surgical, medication-induced, post-viral, and idiopathic.

AREAS COVERED

A comprehensive literature review was conducted to identify studies discussing gastroparesis management. Dietary modifications, medication adjustments, glucose control, antiemetic agents, and prokinetic agents are all part of gastroparesis management. In this manuscript, we detail treatments evolving for gastroparesis, including nutritional, pharmaceutical, device, and recent advanced endoscopic and surgical therapies. This manuscript concludes with a speculative viewpoint on how the field will evolve in 5 years' time.

EXPERT OPINION

Identification of the dominant symptoms (fullness, nausea, abdominal pain, and heartburn) helps to direct management efforts of the patients. Treatments for refractory (treatment resistant) symptoms may include gastric electric stimulation and intra-pyloric interventions like botulinum toxin and endoscopic pyloromyotomy. Understanding the pathophysiology of gastroparesis, relating pathophysiologic abnormalities to specific symptoms, new efficacious pharmacotherapies, and better understanding of the clinical predictors of response of therapies, are priorities for future research in the field of gastroparesis.

Management of Dyspepsia and Gastroparesis in Patients with Diabetes. A Clinical Point of View in the Year 2021

Diabetes mellitus is a widespread disease, and represents an important public health burden worldwide. Together with cardiovascular, renal and neurological complications, many patients with diabetes present with gastrointestinal symptoms, which configure the so-called diabetic enteropathy. In this review, we will focus on upper gastrointestinal symptoms in patients with diabetes, with particular attention to dyspepsia and diabetic gastroparesis (DG). These two clinical entities share similar pathogenetic mechanisms, which include autonomic neuropathy, alterations in enteric nervous system and histological abnormalities, such as interstitial cells of Cajal depletion. Moreover, the differential diagnosis may be challenging because of overlapping clinical features. Delayed gastric emptying should be documented to differentiate between DG and dyspepsia and it can be assessed through radioactive or non-radioactive methods. The clinical management of dyspepsia includes a wide range of different approaches, above all Helicobacter pylori test and treat. As regards DG treatment, a central role is played by dietary modification and glucose control and the first-line pharmacological therapy is represented by the use of prokinetics. A minority of patients with DG refractory to medical treatment may require more invasive therapeutic approaches, including supplemental nutrition, gastric electric stimulation, pyloromyotomy and gastrectomy.

Delayed Gastric Emptying after Esophagectomy: Management and Prevention

The quality of life associated with eating is becoming an increasingly significant problem for patients who undergo esophagectomy as a result of the improved survival rate after esophageal cancer surgery. Delayed gastric emptying (DGE) is a common complication after esophagectomy. Although several strategies have been proposed for the management and prevention of DGE, no clear consensus exists. The purpose of this review is to present a brief overview of DGE and to help clinicians choose the most appropriate treatment through an analysis of DGE by cause. Furthermore, we would like to suggest some tips to prevent DGE based on our experience.

Overall safety of relamorelin in adults with diabetic gastroparesis: Analysis of phase 2a and 2b trial data

BACKGROUND

Relamorelin, a pentapeptide ghrelin receptor agonist, accelerated gastric emptying significantly and improved symptoms in adults with diabetic gastroparesis in phase 2 trials.

AIM

To assess the safety and tolerability of relamorelin across phase 2 trials.

METHODS

Safety assessments in patients aged 18-75 years (weight, adverse events [AEs] and laboratory tests) from two randomised, double-blind phase 2 trials (NCT01571297, NCT02357420; results published previously) were reviewed descriptively. Analysis of covariance assessed treatment effect on glycated haemoglobin (HbA1c) and blood glucose post hoc. Phase 2a and 2b trial durations were, respectively, 4 weeks (relamorelin 10 µg once or twice daily [b.d.] or placebo b.d.) and 12 weeks (relamorelin 10, 30 or 100 µg or placebo b.d.) with 1- and 2-week, single-blind placebo run-ins.

RESULTS

Among 204 phase 2a and 393 phase 2b patients, respectively, 67% and 62% were female, and 88% and 89% had type 2 diabetes. Proportions of patients reporting serious AEs were similar across treatment groups, as were those with ≥1 treatment-emergent AE (TEAE). TEAE-related discontinuations were proportionally higher in relamorelin groups than placebo. Of 12 serious TEAEs in phase 2a, none occurred in >1 patient. In phase 2b, five serious TEAEs were reported in >1 patient, and one (100 µg) died (urosepsis), all unrelated to relamorelin. In phase 2b, increased HbA1c and fasting blood glucose levels were dose-related (P < 0.0001 and P = 0.0043, respectively).

CONCLUSIONS

Relamorelin showed acceptable safety and tolerability in phase 2 trials. Relamorelin may elevate blood glucose: this should be managed proactively in relamorelin-treated patients.

Diabetic Gastroparesis

This review covers the epidemiology, pathophysiology, clinical features, diagnosis, and management of diabetic gastroparesis, and more broadly diabetic gastroenteropathy, which encompasses all the gastrointestinal manifestations of diabetes mellitus. Up to 50% of patients with type 1 and type 2 DM and suboptimal glycemic control have delayed gastric emptying (GE), which can be documented with scintigraphy, 13C breath tests, or a wireless motility capsule; the remainder have normal or rapid GE. Many patients with delayed GE are asymptomatic; others have dyspepsia (i.e., mild to moderate indigestion, with or without a mild delay in GE) or gastroparesis, which is a syndrome characterized by moderate to severe upper gastrointestinal symptoms and delayed GE that suggest, but are not accompanied by, gastric outlet obstruction. Gastroparesis can markedly impair quality of life, and up to 50% of patients have significant anxiety and/or depression. Often the distinction between dyspepsia and gastroparesis is based on clinical judgement rather than established criteria. Hyperglycemia, autonomic neuropathy, and enteric neuromuscular inflammation and injury are implicated in the pathogenesis of delayed GE. Alternatively, there are limited data to suggest that delayed GE may affect glycemic control. The management of diabetic gastroparesis is guided by the severity of symptoms, the magnitude of delayed GE, and the nutritional status. Initial options include dietary modifications, supplemental oral nutrition, and antiemetic and prokinetic medications. Patients with more severe symptoms may require a venting gastrostomy or jejunostomy and/or gastric electrical stimulation. Promising newer therapeutic approaches include ghrelin receptor agonists and selective 5-hydroxytryptamine receptor agonists.

Effects of Promotility Agents on Gastric Emptying and Symptoms: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Studies have reported a lack of association between improvements in gastric emptying (GE) and upper gastrointestinal (UGI) symptoms with promotility drugs. However, GE test methods were suboptimal in some studies. We assessed improvements in GE and UGI symptoms in patients given promotility agents in studies with optimal or moderate test methods (scintigraphy or breath test, solid meal, >2 hours duration) compared to studies with suboptimal GE test methods.

METHODS

With an expert librarian, we completed an extensive search of publications in the Ovid MEDLINE (1946 to present), EMBASE (1988 to January 2018), and EBM Reviews Cochrane Central Register of Controlled Trials, without restrictions on language or year. Two independent reviewers evaluated the following inclusion criteria: randomized, blinded, parallel, or crossover trials of 5HT₄ agonists, D₂ receptor antagonist, or ghrelin agonists; trials that measured change in GE (T_1/2) or composite UGI symptoms; trials of patients with functional dyspepsia and gastroparesis; and trials of GE test methods. Standardized mean differences (units expressed as SD) were used to standardize symptom assessments that were not uniform across studies. Random effects model was used to analyze data and meta-regression was used to evaluate the association between change in GE and UGI symptoms.

RESULTS

Of 899 studies considered, 22 studies assessed change in GE; 23 evaluated UGI symptoms; and 14 evaluated GE and UGI symptoms. Promotility agents significantly accelerated GE (T_1/2) in all studies (mean reduction in T_1/2, 16.3 minutes; 95% confidence interval, -22.1 to -10.6 minutes) and in studies that used optimal GE test methods (mean reduction in T_1/2, 23.6 minutes; 95% confidence interval, -32.3 to -14.9 minutes). Promotility agents also significantly reduced UGI symptoms (mean reduction, 0.25 SD; 95% confidence interval, -0.37 to -0.13 SD). Meta-regression found no significant association between change in GE and UGI symptoms. However, when only studies with optimal GE test methods were evaluated, there was a significant positive association between improvement in GE and UGI symptoms (P = .02).

CONCLUSIONS

In a meta-analysis of published trials, we found promotility agents to significantly accelerate GE (when optimal test methods were used) and to produce significant improvements in UGI symptoms.

Gastroparesis

Gastroparesis is a disorder characterized by delayed gastric emptying of solid food in the absence of a mechanical obstruction of the stomach, resulting in the cardinal symptoms of early satiety, postprandial fullness, nausea, vomiting, belching and bloating. Gastroparesis is now recognized as part of a broader spectrum of gastric neuromuscular dysfunction that includes impaired gastric accommodation. The overlap between upper gastrointestinal symptoms makes the distinction between gastroparesis and other disorders, such as functional dyspepsia, challenging. Thus, a confirmed diagnosis of gastroparesis requires measurement of delayed gastric emptying via an appropriate test, such as gastric scintigraphy or breath testing. Gastroparesis can have idiopathic, diabetic, iatrogenic, post-surgical or post-viral aetiologies. The management of gastroparesis involves: correcting fluid, electrolyte and nutritional deficiencies; identifying and treating the cause of delayed gastric emptying (for example, diabetes mellitus); and suppressing or eliminating symptoms with pharmacological agents as first-line therapies. Several novel pharmacologic agents and interventions are currently in the pipeline and show promise to help tailor individualized therapy for patients with gastroparesis.

Diabetic gastroparesis: current challenges and future prospects

Diabetic gastroparesis (DMGP) is a condition of delayed gastric emptying after gastric outlet obstruction has been excluded. Symptoms of nausea, vomiting, early satiety, bloating, and abdominal pain are associated with DMGP. Uncontrolled symptoms can lead to overall poor quality of life and financial burdens on the healthcare system. A combination of antiemetics and prokinetics is used in symptom control; metoclopramide is the main prokinetic available for clinical use and is the only U.S. Food and Drug Administration-approved agent in the United States. However, a black box warning in 2009 reporting its association with tardive dyskinesia and recommending caution in chronically using this agent beyond 3 months has decreased its role in clinical practice. There is an unmet need for new prokinetics with good efficacy and safety profiles. Currently, there are several new drugs with different mechanisms of action in the pipeline that are under investigation and show promising preliminary results. Surgically combining gastric electrical stimulation with pyloroplasty is considered "gold" standard. Advances in therapeutic endoscopic intervention with gastric per-oral endoscopic pyloromyotomy have also been shown to improve gastric emptying and gastroparesis (GP) symptoms. In this review, we will comment on the challenges encountered when managing patients with DMGP and provide an update on advances in drug development and endoscopic and surgical interventions.

Prokinetics in the Management of Functional Gastrointestinal Disorders

PURPOSE OF REVIEW

The goal of this review is to review the current status of prokinetics and to place it in historical context. Impaired motility and thus propulsion have long been thought to play important roles in the pathogenesis of a number of gastrointestinal disorders including gastroesophageal reflux disease (GERD), gastroparesis, chronic idiopathic pseudo-obstruction, and constipation. Historically, disordered motility was also thought to contribute to a number of functional gastrointestinal disorders such as functional dyspepsia (FD) and irritable bowel syndrome (IBS).

RECENT FINDINGS

As we learn more of the pathophysiology of FD, IBS, GERD, constipation, and gastroparesis, the limitations of a therapeutic strategy based on the stimulation of motility (i.e., the use of a prokinetic) have become apparent and the disappointments of the past explained. The development of prokinetic drugs has also been hampered by the non-selective nature of many of the agents studied to date which resulted in some unexpected side effects. There is still an unmet need for an effective and safe prokinetic, but drug development in this area must be mindful of the challenges of the area and the need for selectivity for a given target receptor.

The pharmacodynamics, safety and pharmacokinetics of single doses of the motilin agonist, camicinal, in type 1 diabetes mellitus with slow gastric emptying

BACKGROUND AND PURPOSE

Here we have investigated the pharmacokinetics, pharmacodynamics and safety of single doses of camicinal in type 1 diabetes mellitus (T1DM) patients with a history of slow gastric emptying with symptoms consistent with gastroparesis.

EXPERIMENTAL APPROACH

In a randomized, double-blind, placebo-controlled, incomplete block, three-period, two-centre crossover study, patients received oral administration of placebo and two of the three possible doses of camicinal (25, 50 or 125 mg). Gastric emptying ((13) C-octanoic acid breath test), pharmacokinetics and safety were primary outcomes.

KEY RESULTS

Nine of the 10 patients enrolled completed the study. Gastric half-emptying time decreased by -95 min (95% CI: -156.8, -34.2) after a single dose of camicinal 125 mg compared with placebo (52 vs. 147 min, P < 0.05), representing a 65% improvement. A decrease of the gastric half-emptying time compared with placebo (approximately 39 min) was observed with camicinal 25 and 50 mg, representing a 27% reduction for both doses (not statistically significant). A positive exposure-response relationship was demonstrated across all doses. The effects of camicinal on gastric half-emptying time were not influenced by fasting glucose levels. Single doses up to 125 mg were well tolerated. Camicinal was well absorbed, exhibiting linear and approximately dose-proportional pharmacokinetic characteristics and a clear exposure-response relationship with gastric emptying.

CONCLUSIONS AND IMPLICATIONS

Camicinal significantly accelerated gastric emptying of solids in T1DM patients following administration of a single oral dose. Camicinal was well tolerated and exhibited similar pharmacokinetic characteristics in diabetic patients to those previously reported in healthy volunteers.

Current and Emerging Medical Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis likely involves various pathophysiological disorders and is increasingly prevalent as complications of surgeries, medications, and chronic diabetes. Key to diagnosis is evidence of delayed gastric emptying, generally based on standardized scintigraphy, and ruling out distal obstruction or other dysmotilities. Initial medical management includes reviewing potentially exacerbating medications and ruling out other reversible causes, achieving tighter glucose control in diabetics, and implementing dietary and lifestyle changes. While current available medications are limited, symptomatic control is aimed at improving gastric emptying, alleviating nausea and vomiting, and treating associated abdominal pain. Other potential therapies are aimed at reducing acid production, improving gastric accommodation or pyloric dysfunction, and treating bacterial overgrowth. Future studies should be aimed toward identification of subpopulations of gastroparetics who are better responders to the various medications based on differences in underlying pathophysiology and adopting standardized study end point measures that may allow for comparisons across trials. This chapter will review current treatment options, upcoming promising medications, and some of the hurdles in advancing the field forward.

Endoscopic approaches to gastroparesis

PURPOSE OF REVIEW

This review covers the cause, evaluation and treatment options for gastroparesis. Symptoms of delayed gastric emptying are increasingly seen by gastroenterologists and gastrointestinal surgeons. Endoscopy - both laparoscopic and flexible - is increasingly important in treatment algorithms for this problem.

RECENT FINDINGS

Gastroparesis is increasingly being seen in clinical practice. A progressive algorithm needs to be followed in these challenging cases: starting with medical treatment and diet modification, progressing through endoscopic treatments including new ones such as per-oral pyloromyotomy, and finally laparoscopic treatments including gastrectomy.

SUMMARY

Endoscopic interventions are effective treatments for certain gastroparesis patients. New procedures offer a minimally invasive alternative to more radical options and should probably be more widely adopted.

Prokinetics in the Management of Functional Gastrointestinal Disorders

A variety of common and some not common gastrointestinal syndromes are thought to be based on impaired gut motility. For some, the role of motility is well defined, for others and the functional gastrointestinal disorders, in particular, the role of hypo- or dysmotility remains unclear. Over the years pharmacological and physiological laboratories have developed drugs which stimulate gut motility; many have been evaluated in motility and functional disorders with what can best be described as mixed results. Lack of receptor specificity and resultant expected and unexpected adverse events have led to the demise of some of these agents. Newer, more selective agents offer promise but the heterogeneity of the clinical disorders they target continues to pose a formidable challenge to drug development in this area.

Drugs acting at 5-HT4 , D2 , motilin, and ghrelin receptors differ markedly in how they affect neuromuscular functions in human isolated stomach

BACKGROUND

Progress in identifying safer, effective drugs to increase gastric emptying is impeded by failed clinical trials. One potential reason for failure is lack of translation from animal models to the human condition. To make progress, the actions of existing drugs and new therapeutic candidates need to be understood in human isolated stomach.

METHODS

Neuromuscular activities were evoked in human gastric antrum circular muscle by electrical field stimulation (EFS), defined phenotypically using pharmacological tools.

KEY RESULTS

EFS evoked cholinergically mediated contractions, attenuated by simultaneous nitrergic activation. The 5-HT4 receptor agonist/D2 antagonist metoclopramide and the selective 5-HT4 agonist prucalopride, facilitated contractions in the absence (respectively, Emax 95 ± 29% and 42 ± 9%, n = 3-6 each concentration) and presence (139 ± 38%, 55 ± 13%, n = 3-5) of the NO synthase inhibitor L-NAME, without affecting submaximal contractions to carbachol; the 5-HT4 antagonist SB204070 prevented facilitation by metoclopramide 100 μM (respectively, -5 (range -26 to 34) and 167 (12-1327)% in presence and absence; n = 5-6). The selective motilin receptor agonist camicinal provided considerably greater facilitation (478 (12-2080)% at 30 μM, n = 8). Domperidone (0.001-100 μM; n = 3-6) and acylated or des-acylated ghrelin (1-300 nM; n = 2-4) had no consistent activity, even with protease inhibitors.

CONCLUSIONS & INFERENCES

5-HT4 receptor agonists show different efficacies. Motilin receptor activation has greater potential to increase gastric emptying, whereas ghrelin and D2 receptor antagonism have no direct activity. Drugs stimulating human gastric motility directly can act regardless of disease mechanisms, whereas drugs without direct activity but an ability to block nausea/vomiting may be effective only if these symptoms exist.

Motilin: towards a new understanding of the gastrointestinal neuropharmacology and therapeutic use of motilin receptor agonists

The gastrointestinal hormone motilin has been known about for >40 years, but after identification of its receptor and subsequent development of new tools and methods, a reappraisal of its actions is required. Firstly, it is important to note that motilin and ghrelin receptors are members of the same family (similar genomic organization, gastrointestinal distribution and abilities to stimulate gastrointestinal motility), yet each fails to recognize the ligand of the other; and whereas ghrelin and ghrelin receptors are widespread outside the gastrointestinal tract, motilin and its receptors are largely restricted to the gastrointestinal tract. Secondly, although some studies suggest motilin has activity in rodents, most do not, and receptor pseudogenes exist in rodents. Thirdly, motilin preferentially operates by facilitating enteric cholinergic activity rather than directly contracting the muscle, despite the relatively high expression of receptor immunoreactivity in muscle. This activity is ligand-dependent, with short-lasting actions of motilin contrasting with longer-lasting actions of the non-selective and selective motilin receptor agonists erythromycin and GSK962040. Finally, the use of erythromycin (also an antibiotic drug) to treat patients requiring acceleration of gastric emptying has led to concerns over safety and potential exacerbation of antibiotic resistance. Replacement motilin receptor agonists derived from erythromycin (motilides) have been unsuccessful. New, non-motilide, small molecule receptor agonists, designed to minimize self-desensitization, are now entering clinical trials for treating patients undergoing enteral feeding or with diabetic gastroparesis. Thus, for the translational pharmacologist, the study of motilin illustrates the need to avoid overreliance on artificial systems, on structural information and on animal studies.

LINKED ARTICLES

This article is part of a themed section on Neuropeptides. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.170.issue-7.

Review article: the role of gastrointestinal hormones in the treatment of delayed gastric emptying in critically ill patients

BACKGROUND

Delayed gastric emptying limits the administration of enteral nutrition, leading to malnutrition, which is associated with higher mortality and morbidity. Currently available prokinetics have limitations in terms of sustained efficacy and side effects.

AIM

To summarise the mechanisms of action and to discuss the possible utility of gastrointestinal hormones to prevent or treat delayed gastric emptying in critically ill patients.

METHODS

We searched PubMed for articles discussing 'delayed gastric emptying', 'enteral nutrition', 'treatment', 'gastrointestinal hormones', 'prokinetic', 'agonist', 'antagonist' and 'critically ill patients'.

RESULTS

Motilin and ghrelin receptor agonists initiate the migrating motor complex in the stomach, which accelerates gastric emptying. Cholecystokinin, glucagon-like peptide-1 and peptide YY have an inhibiting effect on gastric emptying; therefore, antagonising these gastrointestinal hormones may have therapeutic potential. Other gastrointestinal hormones appear less promising.

CONCLUSIONS

Manipulation of endogenous secretion, physiological replacement and administration of gastrointestinal hormones in pharmacological doses is likely to have therapeutic potential in the treatment of delayed gastric emptying. Future challenges in this field will include the search for candidates with improved selectivity and favourable kinetic properties.

Laparoscopic gastric electrical stimulation for medically refractory diabetic and idiopathic gastroparesis

BACKGROUND

Gastric electrical stimulator (GES) implantation is effective in certain patients with gastroparesis; however, laparotomy is often employed for placement. The aim of this study is to review outcomes of patients who underwent laparoscopic GES therapy for diabetic and idiopathic gastroparesis at a large referral center.

METHODS

Patients who underwent GES (Enterra Therapy System; Medtronic, Minneapolis, MN) implantation with subsequent interrogation and programming between March 2001 and November 2011 were analyzed.

RESULTS

A total of 113 patients underwent GES placement or revision during the study period. One hundred eleven patients underwent primary GES at our institution, while two patients underwent GES generator revision at our institution. Primary operations were completed laparoscopically in 110 of 111 cases, with one conversion to laparotomy due to severe adhesions. At a mean follow-up of 27 months (1-113), symptom improvement was achieved in 91 patients (80 %) and was similar for both the diabetic and idiopathic subgroups. Need for supplemental nutrition (enteral and/or parental) decreased in both groups.

CONCLUSIONS

GES placement is feasible using a laparoscopic approach. Medical refractory gastroparesis in the diabetic and idiopathic groups had significant symptom improvement with no difference between the two groups. Need for supplemental nutrition is decreased following GES.

Regional- and agonist-dependent facilitation of human neurogastrointestinal functions by motilin receptor agonists

BACKGROUND AND PURPOSE

Delayed gastric emptying is poorly managed. Motilin agonists are potential treatments but inadequate understanding into how enteric nerve functions are stimulated compromises drug/dose selection. Resolution is hampered by extreme species dependency so methods were developed to study human gastrointestinal neuromuscular activities and the neurobiology of motilin.

EXPERIMENTAL APPROACH

Protocols to study neuromuscular activities were developed for different regions of human stomach and intestine (71 patients) using circular muscle preparations and electrical field stimulation (EFS) of intrinsic nerves. Other tissues were fixed for immunohistochemistry.

KEY RESULTS

EFS evoked contractions and/or relaxations via cholinergic and nitrergic neurons, with additional tachykinergic activity in colon; these were consistent after 154 min (longer if stored overnight). Motilin 1-300 nM and the selective motilin agonist GSK962040 0.1-30 µM acted pre-junctionally to strongly facilitate cholinergic contractions of the antrum (E(max) ≈ 1000% for motilin), with smaller increases in fundus, duodenum and ileum; high concentrations increased baseline muscle tension in fundus and small intestine. There were minimal effects in the colon. In the antrum, cholinergic facilitation by motilin faded irregularly, even with peptidase inhibitors, whereas facilitation by GSK962040 was long lasting. Motilin receptor immunoreactivity was identified in muscle and myenteric plexus predominantly in the upper gut, co-expressed with choline acetyltransferase in neurons.

CONCLUSIONS AND IMPLICATIONS

Motilin and GSK962040 strongly facilitated cholinergic activity in the antrum, with lower activity in fundus and small intestine only. Facilitation by motilin was short lived, consistent with participation in migrating motor complexes. Long-lasting facilitation by GSK962040 suggests different receptor interactions and potential for clinical evaluation.

Pharmakologische Aspekte

Kortikosteroide waren die ersten Therapeutika zur Kontrolle von Abstoßungsreaktionen nach Transplantation. Sie sind seit Langem und immer noch wichtiger Bestandteil vieler immunsuppressiver Therapiekonzepte. Kortikosteroide besitzen zahlreiche antiinflammatorische und immunsuppressive Effekte. Sie beeinflussen über die Bindung spezifischer zytoplasmatischer Rezeptoren die Gentranskriptionsrate für zentrale, immunregulatorische Proteine wie Interleukin 1β (IL-1β), IL-6, Tumor-Nekrose-Faktor α (TNF-α) mit resultierender Suppression der Makrophagenfunktion und konsekutiver T-Zell-Aktivierung. Sie inhibieren auch die IL-2-Synthese, hemmen damit die T-Zell-Proliferation und reduzieren die IL- 2-Rezeptorbindungsfähigkeit. Andererseits stimulieren sie die Synthese des inhibierenden Zytokins „transforming growth factor β“ (TGF-β), was in einem „antiinflammatorisch“ geprägten T-Helfer-Zell-2-artigen Zytokinprofil resultiert. Über die Inhibition der Expression von interferonabhängigen Adhäsionsmolekülen (einschließlich MHC-Klasse-II-Moleküle) bewirken Kortikosteroide darüber hinaus die Alteration von Leukozytenverkehr und -transmigration sowie eine Induktion der Lymphozytenapoptose.

Anti-emetic and emetic effects of erythromycin in Suncus murinus: role of vagal nerve activation, gastric motility stimulation and motilin receptors

Paradoxically, erythromycin is associated with nausea when used as an antibiotic but at lower doses erythromycin activates motilin receptors and is used to treat delayed gastric emptying and nausea. The aim of this study was to characterise pro- and anti-emetic activity of erythromycin and investigate mechanisms of action. Japanese House musk shrews (Suncus murinus) were used. Erythromycin was administered alone or prior to induction of emesis with abnormal motion or subcutaneous nicotine (10mg/kg). The effects of erythromycin and motilin on vagal nerve activity and on cholinergically mediated contractions of the stomach (evoked by electrical field stimulation) were studied in vitro. The results showed that erythromycin (1 and 5mg/kg) reduced vomiting caused by abnormal motion (e.g., from 10.3 ± 1.8 to 4.0 ± 1.1 emetic episodes at 5mg/kg) or by nicotine (from 9.5 ± 2.0 to 3.1 ± 2.0 at 5mg/kg), increasing latency of onset to emesis; lower or higher doses had no effects. When administered alone, erythromycin 100mg/kg induced vomiting in two of four animals, whereas lower doses did not. In vitro, motilin (1, 100 nM) increased gastric vagal afferent activity without affecting jejunal afferent mesenteric nerve activity. Cholinergically mediated contractions of the stomach (prevented by tetrodotoxin 1 μM or atropine 1 μM, facilitated by l-NAME 300 μM) were facilitated by motilin (1-100 nM) and erythromycin (10-30 μM). In conclusion, low doses of erythromycin have anti-emetic activity. Potential mechanisms of action include increased gastric motility (overcoming gastric stasis) and/ or modulation of vagal nerve pathways involved in emesis, demonstrated by first-time direct recording of vagal activation by motilin.

Systemic sclerosis--challenges for clinical practice

The management of patients with systemic sclerosis (SSc) can be challenging because disease-associated damage is often difficult to reverse and curative therapies are not yet available. Early identification and appropriate monitoring of patients with SSc is, therefore, critical so that active disease can be controlled and tissue damage prevented or delayed. However, early diagnosis of SSc is often difficult because the early clinical stages of the disease can be very similar to that of other autoimmune conditions. Screening for major organ manifestations of SSc, particularly interstitial lung disease, pulmonary hypertension, renal involvement and cardiac disease is a priority because involvement of these organs is associated with shorter life expectancies and early intervention might prevent disease progression. The prevention and management of digital ischaemia is also important as appropriate therapy often prevents substantial morbidity and functional loss. Treating gastrointestinal dysmotility can usually be managed using proton pump inhibitors and promotility agents, although in severe cases total parenteral nutrition is required. Calcinosis in patients with SSc is another common challenge that requires appropriate disease management and pain control. Each of these topics, which are relevant to both physicians and patients with SSc, are reviewed in further detail herein.

Diabetic gastrointestinal autonomic neuropathy: current status and new achievements for everyday clinical practice

Gastrointestinal symptoms occur frequently among patients with diabetes mellitus and are associated with considerable morbidity. Diabetic gastrointestinal autonomic neuropathy represents a complex disorder with multifactorial pathogenesis, which is still not well understood. It appears to involve a spectrum of metabolic and cellular changes that affect gastrointestinal motor and sensory control. It may affect any organ in the digestive system. Clinical manifestations are often underestimated, and therefore autonomic neuropathy should be suspected in all diabetic patients with unexplained gastrointestinal symptoms. Advances in technology have now enabled assessment of gastrointestinal motor function. Moreover, novel pharmacological approaches, along with endoscopic and surgical treatment options, contribute to improved outcomes. This review summarises the progress achieved in diabetic gastrointestinal autonomic neuropathy during the last years, focusing on clinical issues of practical importance to the everyday clinician.

Motilin receptor neuropharmacology: revised understanding

Although motilin was identified >40 years ago as a gastrointestinal hormone capable of stimulating gastric emptying, the relatively recent availability of molecular tools and focus on its neuronal activities are now clarifying mechanisms of action. In rodents, only motilin receptor pseudogenes are identified. In human stomach, facilitation of enteric cholinergic activity is identified as the main mechanism by which gastric emptying is increased; some motilin agonists act in a prolonged manner, contrasting with motilin itself and with studies using recombinant receptors. As such, assays using recombinant receptors seem poor predictors of in vivo activity. High-throughput screening enabled selective motilin agonists to be identified, which together with enhanced understanding into neuromuscular actions of motilin, promises to deliver rational treatments of disorders with delayed gastric emptying.

Clinical presentation, response to therapy, and outcome of gastroparesis in children

OBJECTIVES

The aims of the present study was to define the clinical features, response to therapy, and outcome of pediatric gastroparesis.

METHODS

Retrospective review of 230 children with gastroparesis. Demographics, gastric emptying times, symptoms, response to medications, and outcome were determined for each of 3 groups (infants, children, and adolescents).

RESULTS

Mean age was 9 years, with boys predominating among infants and girls among adolescents. Postviral gastroparesis occurred in 18% and mitochondrial dysfunction (MD) in 8%. Symptoms varied with age, with children experiencing more vomiting and adolescents reporting more nausea and abdominal pain. The addition of promotility drugs was an effective therapy. Overall rates of symptom resolution were 22% at 6 months, 53% at 18 months, and 61% at 36 months, with median time to resolution of 14 months. Factors associated with symptom resolution included younger age, male sex, postviral gastroparesis, shorter duration of symptoms, response to addition of promotility therapy, and absence of MD. In multivariate analysis, longer duration of symptoms and MD both predicted lower rates of resolution, whereas younger age and response to addition of promotility therapy predicted a higher rate.

CONCLUSIONS

Pediatric gastroparesis is a complex condition with variable symptomatology and outcome depending on multiple parameters. Understanding the clinical features and response to therapy will improve our diagnosis and treatment of this disorder.

The hungry stomach: physiology, disease, and drug development opportunities

During hunger, a series of high-amplitude contractions of the stomach and small intestine (phase III), which form part of a cycle of quiescence and contractions (known as the migrating motor complex, MMC), play a "housekeeping" role prior to the next meal, and may contribute toward the development of hunger. Several gastrointestinal (GI) hormones are associated with phase III MMC activity, but currently the most prominent is motilin, thought to at least partly mediate phase III contractions of the gastric MMC. Additional GI endocrine and neuronal systems play even more powerful roles in the development of hunger. In particular, the ghrelin-precursor gene is proving to have a complex physiology, giving rise to three different products: ghrelin itself, which is formed from a post-translational modification of des-acyl-ghrelin, and obestatin. The receptors acted on by des-acyl-ghrelin and by obestatin are currently unknown but both these peptides seem able to exert actions which oppose that of ghrelin, either indirectly or directly. An increased understanding of the actions of these peptides is helping to unravel a number of different eating disorders and providing opportunities for the discovery of new drugs to regulate dysfunctional gastric behaviors and appetite. To date, ghrelin and motilin receptor agonists and antagonists have been described. The most advanced are compounds which activate the ghrelin and motilin receptors which are being progressed for disorders associated with gastric hypomotility.

Erythromycin inhibited glycinergic inputs to gastric vagal motoneurons in brainstem slices of newborn rats

BACKGROUND

Motilin has been known to stimulate the motility of digestive organs peripherally via activation of motilin receptors located at gastrointestinal (GI) cholinergic nerve endings and/or smooth muscle cells. Recent studies have indicated that motilin may also promote GI motility via actions in the central nervous system; however the sites of action and the mechanisms are not clear yet. The present study aimed to test the hypothesis that motilin receptor agonist erythromycin alters the synaptic inputs of preganglionic gastric vagal motoneurons (GVMs) located in the dorsal motor nucleus of the vagus (DMV).

METHODS

Gastric vagal motoneurons were retrogradely labeled by fluorescent tracer from the stomach wall of newborn rats. Fluorescently labeled GVMs in DMV were recorded using whole-cell patch-clamp in brainstem slices and the effects of motilin receptor agonist erythromycin on the synaptic inputs were examined.

KEY RESULTS

Erythromycin (100 nmol L(-1), 1 μmol L(-1), 10 μmol L(-1)) significantly inhibited the frequency of glycinergic spontaneous inhibitory postsynaptic currents (sIPSCs) of GVMs and significantly inhibited the amplitude at the concentration of 10 μmol L(-1). These responses were prevented by GM-109, a selective motilin receptor antagonist. In the pre-existence of tetradotoxin (TTX, 1 μmol L(-1)), erythromycin (10 μmol L(-1)) caused significant decreases of the glycinergic miniature inhibitory postsynaptic currents (mIPSCs), in both the frequency and the amplitude. However, erythromycin (10 μmol L(-1)) didn't cause significant changes of the GABAergic sIPSCs.

CONCLUSIONS & INFERENCES

Erythromycin selectively inhibits the glycinergic inputs of GVMs.

Gastrointestinal dysfunction in Parkinson's disease

In recent years, an increasingly detailed picture of gastrointestinal dysfunction in the setting of Parkinson's disease has emerged. Abnormalities of function may occur at virtually all levels of the gastrointestinal tract. Weight loss, dental deterioration, salivary excess, dysphagia, gastroparesis, decreased bowel movement frequency, and anorectal dysfunction all may occur. The pathophysiologic basis for this dysfunction entails both central and enteric nervous system involvement.

Different faces of gastroparesis

AIM: To test the hypothesis that pain and affect rather than impaired emptying determine symptom severity in patients with gastroparesis.

METHODS: Adult patients with documented gastroparesis were enrolled prospectively in a single center and asked to complete the Gastroparesis Cardinal Symptom Index (GCSI), Hospital Anxiety and Depression Scale (HADS), the Short Form 12 (SF-12) as quality of life index, rate pain severity and answer 10 open-ended questions.

RESULTS: A total of 55 patients (44 women) participated. Idiopathic (n = 29) or diabetic (n = 11) gastroparesis and connective tissue disease (n = 8) were the most common underlying causes. Antiemetics (n = 30) and prokinetics (n = 32) were most often prescribed. Seventeen patients used opioids on a daily basis. Nausea and/or vomiting (n = 28), pain (n = 24) and bloating (n = 14) were most commonly listed as dominant symptoms. Patients subjectively attributed symptom improvement to nutritional and dietary therapy (n = 11), prokinetics (n = 11), antiemetics (n = 10) or analgesic agents (n = 3). In univariate analyses, the physical subscore of the SF-12 and HADS, but not gastric emptying delay or symptom duration significantly correlated with disease severity as measured by the GCSI. In multivariate analyses, the combination of vomiting, bloating and depression best predicted the overall impact on quality of life.

CONCLUSION: The study confirms the importance of pain and affect in gastroparesis, which requires novel approaches to improve more effectively the quality of life in patients with this disorder.

Diabetic gastroparesis: diagnosis and management

Gastric emptying is frequently abnormal in patients with long-standing type 1 and type 2 diabetes mellitus. Symptoms commonly associated with disordered gastric emptying include nausea, vomiting, bloating and epigastric pain, while patients are also at risk of malnutrition, weight loss, impaired drug absorption, disordered glycaemic control and poor quality of life. Although often attributed to the presence of irreversible autonomic neuropathy, acute hyperglycaemia represents a potentially reversible cause of gastric dysfunction in diabetes. Scintigraphy represents the gold standard for measuring gastric emptying. The management of diabetic gastroparesis is less than optimal, partly because the pathogenesis has not been clearly defined. Treatment approaches include dietary modification and optimization of glycaemia, and the use of prokinetic drugs, while novel therapies such as gastric electrical stimulation are the subject of ongoing investigation.

Pathophysiology and management of gastroparesis

Gastroparesis is characterized by upper gastrointestinal symptoms associated with delayed gastric emptying, without mechanical obstruction. However, symptoms do not correlate well with the magnitude of delay in gastric emptying. Diabetes mellitus and surgery are the most common causes, although more than 30% of cases are idiopathic. Coordination of insulin action with nutrient delivery is important in diabetics, as postprandial blood glucose levels and gastric emptying are interdependent, and gastroparesis probably represents a major cause of poor glycemic control. Scintigraphy is the gold standard for measuring gastric emptying. Current treatment mainly involves the use of prokinetic drugs. Pyloric botulinum toxin injection and gastric electrical stimulation require more evidence from controlled studies before their use can be recommended. Surgical options remain inadequately studied.

Current treatment of nausea and vomiting associated with gastroparesis: antiemetics, prokinetics, tricyclics

Gastroparesis is a symptomatic chronic disorder characterized by delayed gastric emptying without a mechanical obstruction. Gastroparesis is most often associated with diabetes, gastric surgery, and systemic disorders affecting the neuromuscular control of the stomach. However, no underlying etiology can be found in up to 40% of patients, a condition referred to as idiopathic gastroparesis. Due to the numerous potential etiologies and the highly variable clinical manifestations, the management of gastroparesis is particularly challenging. The purpose of this review is to provide an update on the use of antiemetics, prokinetics, and tricyclics for the treatment for nausea and vomiting associated with gastroparesis.

Identification of small molecule agonists of the motilin receptor

High-throughput screening resulted in the identification of a series of novel motilin receptor agonists with relatively low molecular weights. The series originated from an array of biphenyl derivatives designed to target 7-transmembrane (7-TM) receptors. Further investigation of the structure-activity relationship within the series resulted in the identification of compound (22) as a potent and selective agonist at the motilin receptor.

Review article: gastroparesis

BACKGROUND

Gastroparesis is a chronic disorder caused by stomach pump failure and characterized by profound nausea, vomiting and epigastric pain. Most often, the cause is unapparent and of the known associations, diabetes is the most common. Diagnosis is usually made using an isotope-labelled test meal. Treatment is incremental and includes education, dietary support, prokinetic and antiemetic agents. There are novel approaches including gastric neurostimulation.

AIM

To review current concepts of gastric motor function, aetiology, investigation and treatment of gastroparesis.

METHODS

A systematic web-based review of the literature was undertaken using a lexicon of terms associated with gastroparesis.

RESULTS

There are few controlled studies of this condition. Little is known about causation or underlying nerve, muscle or pacemaker pathology. Idiopathic gastroparesis occurs most commonly in women and gastric emptying is often abnormal in diabetes. Isotopic gastric scintigraphy remains the gold standard investigation, but alternative tests are being developed. Treatment is multimodal and includes education, and nutritional support. There are no adequately powered controlled trials to support a particular drug regimen. In intractable gastroparesis, gastric neurostimulation appears to offer benefit.

CONCLUSION

Despite a significant progress in the past decade, further controlled trials are required into the therapeutic options available for treating this intriguing condition.

Hormones of the gut-brain axis as targets for the treatment of upper gastrointestinal disorders

The concept of the gut forming the centre of an integrated gut-brain-energy axis - modulating appetite, metabolism and digestion - opens up new paradigms for drugs that can tackle multiple symptoms in complex upper gastrointestinal disorders. These include eating disorders, nausea and vomiting, gastroesophageal reflux disease, gastroparesis, dyspepsia and irritable bowel syndrome. The hormones that modulate gastric motility represent targets for gastric prokinetic drugs, and peptides that modify eating behaviours may be targeted to develop drugs that reduce nausea, a currently poorly treated condition. The gut-brain axis may therefore provide a range of therapeutic opportunities that deliver a more holistic treatment of upper gastrointestinal disorders.

[Gastroparesis and its treatment options]

Gastroparesis is a disorder of gastric emptying that occurs in the absence of mechanical obstruction. Its cardinal features include nausea, vomiting, bloating, early satiety and discomfort. Weight loss, dehydration, electrolyte disturbances and malnutrition may develop in severe cases. The majority of cases is idiopathic, long standing diabetes mellitus is responsible for about 25-30% of cases. Diabetic gastroparesis may render glucose control extremely difficult, its treatment represents a major challenge. Besides frequent, small meals and psychological support, several drug options are available, however, their efficacy is limited and only a few randomized studies have been performed to date. Prokinetic agents (erythromycin, domperidone, metoclopramide) and antiemetics (phenothiazines, serotonin antagonists, butyrophenones) are the most wide-spread medicaments. Among the novel, recently developed agents, 5-HT4 serotonin receptor agonists and dopamine D2 receptor antagonists are the most promising. Injection of botulinum toxin into the pyloric sphincter resulted in faster gastric emptying and symptom alleviation in some studies. Gastric electric stimulation appears to be one of the most effective options, both low and high-frequency stimulation may alleviate symptoms. Gastrostomy/jejunostomy and other surgical interventions are considered as "last resort".

Development of drugs for gastrointestinal motor disorders: translating science to clinical need

Only a small number of new drugs have recently become available for gastrointestinal (GI) disorders. This is partly because we await outcomes of research into functional bowel disorder aetiology (e.g., role of microbiota) and of trials to control stress- related or painful GI symptoms (e.g., via CRF(1) receptors or beta(3) adrenoceptors). Nevertheless, only the ClC-2 channel activator lubiprostone has recently reached the clinic, joining the 5-HT(3) antagonist alosetron and the long-established 5-HT(4) agonist and D(2) antagonist metoclopramide; tegaserod, a non-selective ligand, was withdrawn. Interestingly, each has shortcomings, providing opportunities for molecules with 5-HT(4) or motilin receptor selectivity, and for new biology via guanylate cyclase C or ghrelin receptor activation. For translation into new drugs, the molecule must have appropriate efficacy, selectivity and pharmacodynamic properties. It is argued that the compound must then be evaluated in conditions where changes in motility are known to exist, before considering more difficult symptomatic conditions such as irritable bowel syndrome (IBS) or functional dyspepsia (FD), where relationships with disordered motility are unclear. Thus, it may be better to begin studying a gastric prokinetic in diabetics requiring improved glucose control, rather than in FD. Notably, new 5-HT(4) receptor agonists are being evaluated firstly as treatments of constipation, not IBS. New antidiarrhoeal agents should be developed similarly. Thus, progression of new drugs may require initial studies in smaller patient populations where clinical outcome is better defined. Only then can disease-related ideas be properly tested and drugs brought forward for these disorders (with high clinical need) and then, if successful for IBS and FD.

Treatment of complications associated with systemic sclerosis

PURPOSE

Current and emerging drug therapy options for patients suffering from the complications of systemic sclerosis are presented.

SUMMARY

Systemic sclerosis is a devastating and rare, chronic, autoimmune disease and is characterized by various disease complications due to skin thickening, vascular damage, and inflammation affecting numerous organs. There are two major subtypes of systemic sclerosis: limited cutaneous scleroderma and diffuse cutaneous scleroderma. Patients suffer from Raynaud's phenomenon, skin changes, musculoskeletal changes, gastrointestinal complications, pulmonary complications, scleroderma renal crisis, and dryness of the eyes and mouth. Currently, there is no cure for systemic sclerosis, but research is focusing on decreasing the progression and symptoms of this disease. Raynaud's phenomenon is the temporary vasoconstriction of the small vessels of the fingers, toes, tip of the nose, and earlobes. Skin thickening is the cardinal symptom of systemic sclerosis, with as many as 50% of patients developing digital ulcers. Care of these ulcers is crucial in the prevention of osteomyelitis and other infections. Malabsorption syndrome may also occur in patients, many of whom will eventually require parenteral nutrition to maintain their caloric needs. Pulmonary interstitial fibrosis and pulmonary arterial hypertension are additional serious complications of systemic sclerosis. The use of prostacyclin analogues, phosphodiesterase inhibitors, calcium-channel blockers, cyclophosphamide, bosentan, and other agents has been investigated in patients suffering from the complications of systemic sclerosis.

CONCLUSION

Systemic sclerosis is characterized by various circulatory, dermatological, gastrointestinal, musculoskeletal, pulmonary, and renal complications. Although there is no cure for systemic sclerosis, management of its associated complications can help improve patients' quality of life.

Motilin, ghrelin and related neuropeptides as targets for the treatment of GI diseases

Motilin and ghrelin are released from the upper gut during fasting, to stimulate gastric motility. Additional actions of ghrelin (e.g. changes in appetite, nausea or endocrine functions) improve the possibility of using ghrelin receptor agonists to treat complex disorders such as functional dyspepsia. However, changes in endocrine functions increase the risk of unacceptable side effects. By comparison, the more restricted prokinetic activity of motilin limits the therapeutic possibilities but improves the risk:benefit ratio. Compounds targeting both receptors are in development. Recently, additional peptides have been identified from preproghrelin (obestatin) and prepromotilin. These exert biological activity but their pathophysiological significance is unknown.

How to manage refractory GERD

Patients who are unresponsive to 4-8 weeks' treatment with PPIs twice daily might have so-called refractory GERD. The first investigation these patients should undergo is upper endoscopy to exclude a diagnosis of peptic ulcer disease or cancer and identify the presence of esophagitis. The presence of esophagitis in these patients is suggestive of a pill-induced injury, an autoimmune skin disease involving the esophagus, eosinophilic esophagitis or, less likely, a hypersecretory syndrome or a genotype that confers altered metabolism of PPIs. Refractory reflux syndromes associated with normal endoscopy findings are more problematic to diagnose and further testing may be required, including prolonged 48 h pH testing, impedance measurements (for nonacid reflux), esophageal manometry and gastric function tests. For patients with refractory GERD who do not have esophagitis, possible etiologies include nocturnal gastric acid breakthrough, nonacid GER, missed GER or other diseases such as achalasia, gastroparesis or functional heartburn.

Rational prescription of drugs within similar therapeutic or structural class for gastrointestinal disease treatment: Drug metabolism and its related interactions

AIM: To review and summarize drug metabolism and its related interactions in prescribing drugs within the similar therapeutic or structural class for gastrointestinal disease treatment so as to promote rational use of medicines in clinical practice.

METHODS: Relevant literature was identified by performing MEDLINE/Pubmed searches covering the period from 1988 to 2006.

RESULTS: Seven classes of drugs were chosen, including gastric proton pump inhibitors, histamine H₂-receptor antagonists, benzamide-type gastroprokinetic agents, selective 5-HT₃ receptor antagonists, fluoroquinolones, macrolide antibiotics and azole antifungals. They showed significant differences in metabolic profile (i.e., the fraction of drug metabolized by cytochrome P450 (CYP), CYP reaction phenotype, impact of CYP genotype on interindividual pharmacokinetics variability and CYP-mediated drug-drug interaction potential). Many events of severe adverse drug reactions and treatment failures were closely related to the ignorance of the above issues.

CONCLUSION: Clinicians should acquaint themselves with what kind of drug has less interpatient variability in clearance and whether to perform CYP genotyping prior to initiation of therapy. The relevant CYP knowledge helps clinicians to enhance the management of patients with gastrointestinal disease who may require treatment with polytherapeutic regimens.

Erythromycin is more effective than metoclopramide in the treatment of feed intolerance in critical illness

OBJECTIVE

This study aimed to a) compare the efficacy of metoclopramide and erythromycin in the treatment of feed intolerance in critical illness; and b) determine the effectiveness of "rescue" combination therapy in patients who fail monotherapy.

DESIGN

Randomized controlled trial.

SETTING

Level III mixed medical and surgical intensive care unit.

PATIENTS

Ninety mechanically ventilated, medical patients with feed-intolerance (gastric residual volume>or=250 mL).

INTERVENTIONS

Patients received either metoclopramide 10 mg intravenously four times daily (n=45) or erythromycin 200 mg intravenously twice a day (n=45) in a double-blind, randomized fashion. After the first dose, nasogastric feeding was commenced and 6-hourly nasogastric aspirates were performed. If a gastric residual volume>or=250 mL recurred on treatment, open-label, combination therapy was given. Patients were studied for 7 days. Successful feeding was defined as 6-hourly gastric residual volume<250 mL with a feeding rate>or=40 mL/hr.

MEASUREMENTS AND MAIN RESULTS

Demographic data, blood glucose levels, and use of inotropes, opioids, and benzodiazepines were similar between the two groups. After 24 hrs of treatment, both monotherapies reduced the mean gastric residual volume (metoclopramide, 830+/-32 mL to 435+/-30 mL, p<.0001; erythromycin, 798+/-33 mL to 201+/-19 mL, p<.0001) and improved the proportion of patients with successful feeding (metoclopramide=62% and erythromycin=87%). Treatment with erythromycin was more effective than metoclopramide, but the effectiveness of both treatments declined rapidly over time. In patients who failed monotherapy, rescue combination therapy was highly effective (day 1=92%) and maintained its effectiveness for the study duration (day 6=67%). High pretreatment gastric residual volume was associated with poor response to prokinetic therapy.

CONCLUSIONS

In critical illness, erythromycin is more effective than metoclopramide in treating feed intolerance, but the rapid decline in effectiveness renders both treatments suboptimal. Rescue combination therapy is highly effective, and further study is required to examine its role as the first-line therapy.

Differences between the abilities of tegaserod and motilin receptor agonists to stimulate gastric motility in vitro

BACKGROUND AND PURPOSE

Motilin or 5-HT4 receptor agonists stimulate gastrointestinal motility. Differences in activity are suggested but direct comparisons are few. A method was devised to directly compare the gastric prokinetic activities of motilin, the motilin receptor agonist, erythromycin, and the 5-HT4 receptor agonist, tegaserod.

EXPERIMENTAL APPROACH

Gastric prokinetic-like activity was assessed by measuring the ability to facilitate cholinergically-mediated contractions evoked by electrical field stimulation (EFS) in rabbit isolated stomach. Comparisons were made between potency, maximal activity and duration of responses.

KEY RESULTS

Rabbit motilin (r.motilin) 0.003-0.3 microM, [Nle13]motilin 0.003-0.3 microM, erythromycin 0.3-10 microM and tegaserod 0.1-10 microM caused concentration - dependent potentiation of EFS-evoked contractions. The potency ranking was r.motilin = [Nle13]motilin > tegaserod > erythromycin. The Emax ranking was r.motilin = [Nle13]motilin = erythromycin > tegaserod. Responses to r.motilin and [Nle13]motilin faded rapidly (t1/2 9 and 11 min, respectively) whereas those to erythromycin and tegaserod were maintained longer (t1/2 24 and 28 min). The difference did not appear to be due to peptide degradation. A second application of [Nle13]motilin was excitatory after 60 min contact and fade of the initial response (responses to 0.03 and 0.1 microM [Nle13]motilin were not different from those caused by the first application).

CONCLUSIONS AND IMPLICATIONS

Prokinetic-like activities of the 5-HT4 agonist tegaserod and the motilin receptor agonists were compared by measuring changes in cholinergically-mediated contractions. This novel approach highlighted important differences between classes (greater Emax of motilin, compared with tegaserod) and for the first time, within each class (short t1/2 for motilin, compared with erythromycin).

Pathophysiology and management of diabetic gastropathy: a guide for endocrinologists

Delayed gastric emptying is frequently observed in patients with long-standing type 1 and type 2 diabetes mellitus, and potentially impacts on upper gastrointestinal symptoms, glycaemic control, nutrition and oral drug absorption. The pathogenesis remains unclear and management strategies are currently suboptimal. Therapeutic strategies focus on accelerating gastric emptying, controlling symptoms and improving glycaemic control. The potential adverse effects of hyperglycaemia on gastric emptying and upper gut symptoms indicate the importance of normalising blood glucose if possible. Nutritional and psychological supports are also important, but often neglected. A number of recent pharmacological and non-pharmacological therapies show promise, including gastric electrical stimulation. As with all chronic illnesses, a multidisciplinary approach to management is recommended, but there are few data regarding long-term outcomes.

Le reflux biliaire duodéno-gastrique et gastro-œsophagien

This study reviews current data regarding duodenogastric and gastroesophageal bile reflux-pathophysiology, clinical presentation, methods of diagnosis (namely, 24-hour intraluminal bile monitoring) and therapeutic management. Duodenogastric reflux (DGR) consists of retrograde passage of alkaline duodenal contents into the stomach; it may occur due to antroduodenal motility disorder (primary DGR) or may arise following surgical alteration of gastoduodenal anatomy or because of biliary pathology (secondary DGR). Pathologic DGR may generate symptoms of epigastric pain, nausea, and bilious vomiting. In patients with concomitant gastroesophageal reflux, the backwash of duodenal content into the lower esophagus can cause mixed (alkaline and acid) reflux esophagitis, and lead, in turn, to esophageal mucosal damage such as Barrett's metaplasia and adenocarcinoma. The treatment of DGR is difficult, non-specific, and relatively ineffective in controlling symptoms. Proton pump inhibitors decrease the upstream effects of DGR on the esophagus by decreasing the volume of secretions; promotility agents diminish gastric exposure to duodenal secretions by improving gastric emptying. In patients with severe reflux resistant to medical therapy, a duodenal diversion operation such as the duodenal switch procedure may be indicated.

Macrolide antibiotics and bronchiolitis obliterans following lung transplantation

The anti-inflammatory effects of macrolide antibiotics are of emerging importance. Over the past 20 years, chronic inflammatory respiratory conditions, including diffuse panbronchiolitis, cystic fibrosis and asthma have benefited from long-term low-dose macrolide therapy. Obliterative bronchiolitis, a form of chronic allograft dysfunction in lung transplant recipients, has been reported to be a condition in which macrolide therapy may be indicated. A number of recent cohort studies have been encouraging. Disease progression was delayed with macrolide antibiotic therapy as patients showed a sustained improvement in pulmonary function tests. Up to now, obliterative bronchiolitis has been resistant to most forms of proposed treatment. This review aims to highlight the etiology of obliterative bronchiolitis, the mechanisms of immunomodulation associated with macrolide therapy and how macrolide therapy may be effective by way of these possible mechanisms.