Look What the Cat Dragged in! Recurrent Clostridioides difficile from a Household Cat

BACKGROUND Clostridioides difficile (C. difficile) is a bacterium that is well known for causing serious diarrheal infections and can even lead to colon cancer if left untreated. Disruption of the normal healthy bacteria in the colon can lead to development of C. difficile colitis. Risk factors for C. difficile infections (CDI) include recent antibiotic exposure, hospital or nursing home stays, inflammatory bowel disease (IBD), or impaired immunity. There is an increasing incidence of community-associated CDI (CA-CDI) in individuals without the common risk factors, which has implicated natural reservoirs, zoonoses, originating from animals such as domestic cats and dogs, livestock, shellfish, and wild animals. CASE REPORT A previously healthy 31-year-old woman with recurrent CA-CDI suspected to be acquired from a household cat represents a novel presentation. The patient had an initial case of severe diarrhea following recent antibiotic exposure, was briefly monitored in hospital, and was diagnosed with CDI. She was trialed on oral vancomycin, which resulted in temporary resolution of her symptoms. Her symptoms recurred, however, and did not improve despite treatment with multiple therapeutic options over a period of months. Ultimately, the patient was not able to achieve long-term resolution of her symptoms until her newly adopted pet cat was treated by a veterinarian. CONCLUSIONS In conclusion, this case report explores the epidemiologic risk factors of zoonotic CA-CDI and the importance of early identification, evaluation, and prevention of disease. This case demonstrates the significance of thorough history taking, contact (pet) tracing, and proper treatment of recurrent CA-CDI.

Safety of Percutaneous Endoscopic Gastrostomy Placement in Patients With SARS-CoV-2 Infection

Background

Coronavirus disease 2019 (COVID-19) can lead to ventilator-dependent chronic respiratory failure and a need for tube feeding. Percutaneous endoscopic gastrostomy (PEG) placement provides more sustainable longer-term enteral access with fewer side effects compared to the long-term nasogastric tube placement. Bleeding is a recognized complication of PEG placement, and many COVID-19 patients are on antiplatelets/anticoagulants, yet minimal data exist on the safety of PEG tube placement in this context.

Methods

A retrospective chart review identified patients who underwent PEG placement between January 2020 and January 2021 at a single institution. Success was defined as PEG placement and use to provide enteral nutrition with no complications requiring removal within 4 weeks.

Results

Thirty-six patients with and 104 age- and sex-matched patients without COVID-19 infection were included. More COVID-19 patients were obese, on anticoagulants, had low serum albumin levels and had a tracheostomy in place. Of those patients, 8.3% with COVID-19 developed PEG-related complications compared to 16.3% without (P = 0.28). PEG success rates in patients with and without COVID-19 were similar at 97.2% and 92.3%, respectively (P = 0.44).

Conclusion

PEG tube placement is comparatively safe in COVID-19 patients who need long-term enteral access.

Inflammatory bowel disease and atherosclerotic cardiovascular disease in U.S. adults—A population-level analysis in the national health interview survey

Objectives

To evaluate the association between inflammatory bowel disease (IBD) and atherosclerotic cardiovascular disease (ASCVD) and whether this association is modified by age or sex.

Methods

We conducted a cross-sectional analysis using data from the 2015–2016 National Health Interview Survey (NHIS). The exposure of interest was self-reported IBD. The outcome of interest was prevalent ASCVD, which included a history of angina, myocardial infarction or stroke. We used survey-specific descriptive statistics to obtain weighted national estimates for IBD and ASCVD prevalence. Logistic regression models were used to assess the association between IBD and ASCVD, progressively adjusting for demographics and traditional risk factors. Effect modification by age and sex was evaluated.

Results

Among participants with IBD, the age-adjusted prevalence of ASCVD was 12.0% compared to 6.9% among those without IBD (p < 0.001). In multivariable regression analyses IBD was associated with increased odds of having ASCVD, even after adjustment for demographics and traditional risk factors (odds ratio 1.58, 95% CI 1.17–2.13). We found statistically significant interaction by age (p < 0.001) whereby those in the younger age strata had the strongest association (fully adjusted odds ratio among 18- to 44-year-olds 3.35, 95% CI 1.75, 6.40) while the association was null in those ≥65 years. Effect modification by sex was not observed.

Conclusion

Our analysis confirms an independent association between IBD and ASCVD in the U.S., particularly among young adults. Further studies are needed to fully establish a causal relationship between IBD and ASCVD, characterize the mechanisms underlying these associations, and identify tailored opportunities for ASCVD prevention in young and middle-aged adults with IBD.

Nutraceuticals as modulators of gut microbiota: Role in therapy

As our knowledge of the various roles of the gut microbiota in the maintenance of homeostasis grows and as we learn how a disrupted microbiota may contribute to disease, therapeutic strategies that target our microbial fellow-travellers become ever more attractive. Most appealing are those interventions that seek to modify or supplement our diet through the addition of nutraceuticals. We now know that our diet, whether in the short or long term, is a major modifier of microbiota composition and function. Of the various nutraceuticals, two categories, prebiotics and probiotics, have received the greatest attention in basic research and product development. While our understanding of the impacts of prebiotics and probiotics on the indigenous microbiota and host biology have been described in great detail in vitro and in animal models, the clinical literature leaves much to be desired. While many claims have been made, few are supported by high quality clinical trials. LINKED ARTICLES: This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc.

Disturbance of the gut microbiota in early-life selectively affects visceral pain in adulthood without impacting cognitive or anxiety-related behaviors in male rats

Disruption of bacterial colonization during the early postnatal period is increasingly being linked to adverse health outcomes. Indeed, there is a growing appreciation that the gut microbiota plays a role in neurodevelopment. However, there is a paucity of information on the consequences of early-life manipulations of the gut microbiota on behavior. To this end we administered an antibiotic (vancomycin) from postnatal days 4-13 to male rat pups and assessed behavioral and physiological measures across all aspects of the brain-gut axis. In addition, we sought to confirm and expand the effects of early-life antibiotic treatment using a different antibiotic strategy (a cocktail of pimaricin, bacitracin, neomycin; orally) during the same time period in both female and male rat pups. Vancomycin significantly altered the microbiota, which was restored to control levels by 8 weeks of age. Notably, vancomycin-treated animals displayed visceral hypersensitivity in adulthood without any significant effect on anxiety responses as assessed in the elevated plus maze or open field tests. Moreover, cognitive performance in the Morris water maze was not affected by early-life dysbiosis. Immune and stress-related physiological responses were equally unaffected. The early-life antibiotic-induced visceral hypersensitivity was also observed in male rats given the antibiotic cocktail. Both treatments did not alter visceral pain perception in female rats. Changes in visceral pain perception in males were paralleled by distinct decreases in the transient receptor potential cation channel subfamily V member 1, the α-2A adrenergic receptor and cholecystokinin B receptor. In conclusion, a temporary disruption of the gut microbiota in early-life results in very specific and long-lasting changes in visceral sensitivity in male rats, a hallmark of stress-related functional disorders of the brain-gut axis such as irritable bowel disorder.

Cytokine imbalance in irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder of unknown etiology; although infection and inflammation have recently been considered as important etiologic agents. A recent meta-analysis showed correlations between cytokine [interleukin-10 (IL-10) and tumor necrosis factor (TNF)] gene polymorphisms and IBS; however, it is still unknown whether patients with IBS have different cytokine profiles compared to healthy population.

METHODS

To determine the relationships between serum/plasma levels or mucosal expression of IL-10/TNF-α and IBS, we conducted a systematic review and meta-analysis based on case-control studies retrieved from PubMed and EMBASE search through August 2013. Standardized mean difference (SMD) was generated by using the inverse variance method. Heterogeneity was assessed based on I(2) values.

KEY RESULTS

Serum/plasma levels of TNF-α tended to be higher in IBS vs controls (p = 0.09); this reached significance in IBS subtypes vs controls and in female patients with IBS. However, serum/plasma levels of IL-10 were not significantly different in IBS patients vs controls. Further analysis of serum/plasma IL-10 levels in IBS subtypes did not show any difference; however, analysis based on gender showed a significantly lower serum/plasma IL-10 levels in male patients with IBS vs male controls (p = 0.02). Colonic IL-10 mRNA had a significantly lower expression in IBS vs control (p = 0.001).

CONCLUSIONS & INFERENCES

There is an imbalance of proinflammatory TNF-α, and anti-inflammatory IL-10, cytokines in IBS. Stratifying IBS patients based on cytokine profile may represent an opportunity for personalized treatment of this condition.

Bifidobacterium infantis 35624 modulates host inflammatory processes beyond the gut

Certain therapeutic microbes, including Bifidobacteria infantis (B. infantis) 35624 exert beneficial immunoregulatory effects by mimicking commensal-immune interactions; however, the value of these effects in patients with non-gastrointestinal inflammatory conditions remains unclear. In this study, we assessed the impact of oral administration of B. infantis 35624, for 6‒8 weeks on inflammatory biomarker and plasma cytokine levels in patients with ulcerative colitis (UC) (n = 22), chronic fatigue syndrome (CFS) (n = 48) and psoriasis (n = 26) in three separate randomized, double-blind, placebo-controlled interventions. Additionally, the effect of B. infantis 35624 on immunological biomarkers in healthy subjects (n = 22) was assessed. At baseline, both gastrointestinal (UC) and non-gastrointestinal (CFS and psoriasis) patients had significantly increased plasma levels of C-reactive protein (CRP) and the pro-inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) compared with healthy volunteers. B. infantis 35624 feeding resulted in reduced plasma CRP levels in all three inflammatory disorders compared with placebo. Interestingly, plasma TNF-α was reduced in CFS and psoriasis while IL-6 was reduced in UC and CFS. Furthermore, in healthy subjects, LPS-stimulated TNF-α and IL-6 secretion by peripheral blood mononuclear cells (PBMCs) was significantly reduced in the B. infantis 35624-treated groups compared with placebo following eight weeks of feeding. These results demonstrate the ability of this microbe to reduce systemic pro-inflammatory biomarkers in both gastrointestinal and non-gastrointestinal conditions. In conclusion, these data show that the immunomodulatory effects of the microbiota in humans are not limited to the mucosal immune system but extend to the systemic immune system.

Review article: probiotics for the treatment of irritable bowel syndrome--focus on lactic acid bacteria

BACKGROUND

Irritable bowel syndrome (IBS) is a poorly understood, yet highly prevalent functional gastrointestinal disorder (FGID). The withdrawal, due to adverse events, of a number of pharmacological agents that were approved for the treatment of IBS has left a therapeutic vacuum for patients suffering from the disorder.

AIM

To review, summarise and critically evaluate current knowledge of lactic acid bacteria (LAB) used to treat IBS.

METHODS

We assessed a comprehensive range of relevant literature from Pubmed, Medline and online sources based on our definition of LAB which included both typical and atypical species, covering Lactobacilli, Bifidobacteria, Enterococci, Streptococci and Bacilli.

RESULTS

Of the 42 trials evaluated examining the efficacy of LAB in IBS, 34 reported beneficial effects in at least one of the endpoints or symptoms examined, albeit with tremendous variation in both the magnitude of effect and the choice of outcome under consideration. However, numerous concerns have been expressed over deficits of trial design and execution relating to strain selection, optimum dosage, mode of action, safety and long-term tolerability in a disorder that can persist throughout the lifetime of affected individuals.

CONCLUSIONS

Progress in the field will require an improved understanding of how the microbiota impacts on health and disease, adequately powered long-term multicentre trials and the embracing of bench to bedside approaches. Recent incremental advances suggest these areas are being addressed and that the future holds much promise for the use of lactic acid bacteria in the treatment of irritable bowel syndrome.

Altered peripheral toll-like receptor responses in the irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a stress-related disorder with disturbed brain-gut communication, gastrointestinal homeostasis and, based on recent evidence, low grade inflammation and an altered microbiota. The immune system is a critical regulator of the brain-gut axis. Toll-like receptors (TLRs) are pattern recognition molecules regulating innate immunity.

AIM

To characterise toll-like receptor activity in IBS.

METHODS

Thirty IBS patients and 30 healthy controls (HC) were recruited. Venous blood was collected, and cultured with a panel of toll-like receptor agonists for 24 h. Cell supernatants were analysed using a multiplex ELISA approach to measure IL1β, IL6, IL8 and TNFα. Plasma was analysed for levels of inflammatory cytokines and cortisol.

RESULTS

Toll-like receptor agonist-induced cytokine (IL1β, IL6, IL8 and TNFα) release was markedly enhanced in stimulated whole blood from IBS (n = 30) patients compared with healthy controls (n = 30). An exaggerated response to the TLR8 agonist for all cytokines investigated was seen in IBS patients. In addition, enhanced TLR2-induced TNFα release, TLR3-induced IL-8 release, TLR4-induced IL1β and TNFα release, TLR5-induced IL1β and TNFα release and TLR7-induced IL-8 release were also observed in IBS patients. No differences in TLR1, TLR6 or TLR9 activity were detected. In addition, plasma levels of cortisol, IL-6 and IL-8 were significantly increased in IBS patients.

CONCLUSION

Taken together, these data demonstrate elevated cytokine levels and toll-like receptor activity in the periphery of patients with the irritable bowel syndrome, indicating some immune dysregulation in these patients.

Constipation, IBs and the 5-HT4 Receptor: What Role for Prucalopride?

After the problems associated with the non-selective 5-HT4 receptor agonists cisapride and tegaserod, the 5-HT4 receptor is now beginning to come in from the cold. Thus, prucalopride is now the first of a new class of drug defined by selectivity and high intrinsic activity at the 5-HT4 receptor. Prucalopride has been developed for treatment of chronic constipation rather than constipation-predominant irritable bowel syndrome (IBS). This follows the trend of first evaluating new gastrointestinal (GI) prokinetic drugs in disorders where disrupted GI motility is known to exist, rather than in a functional bowel disorder where changes in motility are uncertain. If prucalopride is not progressed towards the IBS indication, it has at least shown the way for other selective 5-HT4 receptor agonists. Most notable among these is TD-5108 (velusetrag), also characterized by good selectivity at the 5-HT4 receptor, high intrinsic activity and efficacy in patients with chronic constipation.

Composition and energy harvesting capacity of the gut microbiota: relationship to diet, obesity and time in mouse models

BACKGROUND AND AIMS

Increased efficiency of energy harvest, due to alterations in the gut microbiota (increased Firmicutes and decreased Bacteroidetes), has been implicated in obesity in mice and humans. However, a causal relationship is unproven and contributory variables include diet, genetics and age. Therefore, we explored the effect of a high-fat (HF) diet and genetically determined obesity (ob/ob) for changes in microbiota and energy harvesting capacity over time.

METHODS

Seven-week-old male ob/ob mice were fed a low-fat diet and wild-type mice were fed either a low-fat diet or a HF-diet for 8 weeks (n=8/group). They were assessed at 7, 11 and 15 weeks of age for: fat and lean body mass (by NMR); faecal and caecal short-chain fatty acids (SCFA, by gas chromatography); faecal energy content (by bomb calorimetry) and microbial composition (by metagenomic pyrosequencing).

RESULTS

A progressive increase in Firmicutes was confirmed in both HF-fed and ob/ob mice reaching statistical significance in the former, but this phylum was unchanged over time in the lean controls. Reductions in Bacteroidetes were also found in ob/ob mice. However, changes in the microbiota were dissociated from markers of energy harvest. Thus, although the faecal energy in the ob/ob mice was significantly decreased at 7 weeks, and caecal SCFA increased, these did not persist and faecal acetate diminished over time in both ob/ob and HF-fed mice, but not in lean controls. Furthermore, the proportion of the major phyla did not correlate with energy harvest markers.

CONCLUSION

The relationship between the microbial composition and energy harvesting capacity is more complex than previously considered. While compositional changes in the faecal microbiota were confirmed, this was primarily a feature of high-fat feeding rather than genetically induced obesity. In addition, changes in the proportions of the major phyla were unrelated to markers of energy harvest which changed over time. The possibility of microbial adaptation to diet and time should be considered in future studies.

Pharmacological management of constipation

The approach of this review is to give a pragmatic approach to using laxatives, based on a combination of what is known about mechanism of action and the available literature on evidence.

Diagnosis and management of non-erosive reflux disease--the Vevey NERD Consensus Group

BACKGROUND/AIMS

Although considerable information exists regarding gastroesophageal reflux disease with erosions, much less is known of non-erosive reflux disease (NERD), the dominant form of reflux disease in the developed world.

METHODS

An expert international group using the modified Delphi technique examined the quality of evidence and established levels of agreement relating to different aspects of NERD. Discussion focused on clinical presentation, assessment of clinical outcome, pathobiological mechanisms, and clinical strategies for diagnosis and management.

RESULTS

Consensus was reached on 85 specific statements. NERD was defined as a condition with reflux symptoms in the absence of mucosal lesions or breaks detected by conventional endoscopy, and without prior effective acid-suppressive therapy. Evidence supporting this diagnosis included: responsiveness to acid suppression therapy, abnormal reflux monitoring or the identification of specific novel endoscopic and histological findings. Functional heartburn was considered a separate entity not related to acid reflux. Proton pump inhibitors are the definitive therapy for NERD, with efficacy best evaluated by validated quality-of-life instruments. Adjunctive antacids or H(2) receptor antagonists are ineffective, surgery seldom indicated.

CONCLUSIONS

Little is known of the pathobiology of NERD. Further elucidation of the mechanisms of mucosal and visceral hypersensitivity is required to improve NERD management.

Isolation of lactobacilli with probiotic properties from the human stomach

AIMS

Recent evidence suggests that the human gastric microbiota is much more diverse than previously thought. The aim of this study was to assess the potential for isolating lactobacilli from the human stomach.

METHODS AND RESULTS

Lactobacilli were selectively cultured from gastric biopsies from 12 patients undergoing routine endoscopy. Lactobacilli were present in four of 12 biopsies. We isolated, in total 10 different strains representing five species (Lactobacillus gasseri, L. fermentum, L. vaginalis, L. reuteri and L. salivarius). The 10 isolates varied greatly in their ability to inhibit the growth of two Gram-positive bacteria and two Gram-negative bacteria. Furthermore, the acid and bile resistance profiles of the 10 isolates spanned a wide range.

CONCLUSIONS

Five different Lactobacillus species were cultured from human gastric biopsies for the first time.

SIGNIFICANCE AND IMPACT OF THE STUDY

Diverse Lactobacillus species are more prevalent in the human stomach than previously recognized, representing an untapped source of bacteria with beneficial probiotic and/or biotechnological properties.

Functional dyspepsia and nonerosive reflux disease: clinical interactions and their implications

Functional dyspepsia or nonulcer dyspepsia, and nonerosive reflux disease (NERD) or endoscopy-negative reflux disease, are common reasons for referral to a gastroenterologist. Although there is much confusion with regard to definition, recent research would suggest that these 2 conditions are linked and may represent components in the spectrum of the same disease entity, in terms of both symptoms and pathophysiology. Several theories have been proposed regarding the etiology of these disorders, including acid exposure, visceral hypersensitivity, impaired fundal accommodation, delayed gastric emptying, and Helicobacter pylori infection.

Small intestinal transplantation

The past few years have witnessed a considerable shift in the clinical status of intestinal transplantation. A great deal of experience has been gained at the most active centers, and results comparable with those reported at a similar stage in the development of other solid-organ graft programs are now being achieved by these highly proficient transplant teams. Rejection and its inevitable associate, sepsis, remain ubiquitous, and new immunosuppressant regimes are urgently needed; some may already be on the near horizon. The recent success of isolated intestinal grafts, together with the mortality and morbidity attendant upon the development of advanced liver disease related to total parenteral nutrition, has prompted the bold proposal that patients at risk for this complication should be identified and should receive isolated small bowel grafts before the onset of end-stage hepatic failure. The very fact that such a suggestion has begun to emerge reflects real progress in this challenging field.

Colorectal cancer screening compliance by medicine residents: perceived and actual

OBJECTIVE

Implementation of colorectal cancer (CRC) screening with widely available techniques can result in a significant reduction in CRC-related mortality. Clinical practice paradigms are often ingrained in physicians during residency. We, therefore, investigated both compliance and perceived obstacles to CRC screening in the practices of physicians-in-training.

METHODS

We conducted a retrospective analysis of medical records of patients who were receiving their primary care in the internal medicine resident clinics at the University of Nebraska Medical Center and were at average risk for CRC. In addition to demographics, data on the use of screening mammography, Pap smear, cholesterol, fecal occult blood testing (FOBT), and flexible sigmoidoscopy (FS) were collected. A questionnaire was also distributed to all internal medicine residents to assess their CRC screening knowledge and perceived screening compliance.

RESULTS

One hundred eight patient charts were reviewed. The percentage of patients appropriately screened for each test was as follows: mammography 66%, Pap smear 65%, cholesterol 53%, FOBT 13%, and FS 16%. Residents dramatically overestimated their perceived FS and FOBT screening rates, 78% and 88%, respectively. Most residents identified barriers to FS screening. Although rudimentary CRC screening knowledge appeared adequate, a number of knowledge-based deficiencies were identified.

CONCLUSIONS

Internal medicine residents at our institution demonstrate poor CRC screening compliance especially when compared with other health care maintenance interventions. This cannot be entirely accounted for by inadequate knowledge; discrepancy between the perceived and actual implementation of CRC screening may be important. Efforts to improve screening compliance should include a focus on physicians-in-training.

Gastric myoelectrical activity and its relationship to the development of nausea and vomiting after intensive chemotherapy and autologous stem cell transplantation

OBJECTIVES

Gastric motor dysfunction may be responsible, in some patients, for the nausea and emesis that occur after high-dose chemotherapy (HDT) and autologous stem cell transplantation (SCT). Because gastric myoelectrical abnormalities may result in nausea and vomiting in other contexts, we sought to define the prevalence of these abnormalities and their relationship to the development of nausea and vomiting in patients undergoing autologous HDT and SCT, and to determine whether electrogastrography (EGG) could serve to detect gastric motor dysfunction in this population.

METHODS

We prospectively studied patients with a variety of malignancies who received standard transplantation doses of chemotherapeutic agents and antiemetics. Gastric emptying scintigraphy was performed before HDT. Gastric myoelectrical activity was assessed before HDT and on days 0, 7, 14, 21, and 28 from SCT using cutaneous EGG electrodes and a portable EGG recorder, and was analyzed by means of a dedicated software program after removal of motion artifact. Symptom assessment was obtained daily from initiation of HDT to 28 days after SCT.

RESULTS

A total of 25 patients were studied: 13 women and 12 men, with a median age of 50 yr (range = 32-65 yr). Before HDT, gastric emptying scintigraphy was normal in all patients (median T(1/2) of 50 min [range = 22-75 min]) and only one patient had mild nausea and anorexia. Nausea, emesis, and anorexia occurred in all patients, peaked in severity at day +7 from SCT and, with the exception of anorexia, had returned toward baseline levels by day +28. Fasting dysrhythmias were present in 63% of the studies at baseline. Serial EGG recordings revealed significant slowing of the dominant frequency with a consequent decrease in tachygastria and increase in normogastria and bradygastria as the symptoms peaked in severity with a subsequent return to baseline values at the study's end. The only clinical variable that was predictive of symptom severity was gender. Women had a higher risk of developing anorexia (score > or = 2) at day +14 compared to men (odds ratio = 11.2; 95% CI = 1.7-76.9; p = 0.01).

CONCLUSIONS

Baseline abnormalities in gastric myoelectrical activity occur frequently in patients who undergo HDT and autologous SCT despite normal gastric emptying scintigraphy and an absence of symptoms. Although slowing of the dominant frequency was seen as symptoms worsened, we failed to identify any EGG parameter at baseline that could predict the severity of nausea, vomiting or anorexia after transplantation.

Non-erosive reflux disease: part of the spectrum of gastro-oesophageal reflux disease, a component of functional dyspepsia, or both?

Over the last several decades, the incidences of gastric cancer and peptic ulcer have declined while the incidences of gastro-oesophageal reflux disease (GORD) and functional dyspepsia have reached virtually epidemic proportions. A similar trend is occurring in oesophageal cancer, with squamous cell carcinoma on the decline and adenocarcinoma on the rise, possibly due to the dramatic increase in GORD. The true clinical spectrum of these disorders, however, is only recently becoming evident: 60% of patients with GORD do not have detectable evidence of oesophagitis; they can be classified as having non-erosive or negative-endoscopy reflux disease (NERD). In this subgroup, a significant proportion will also manifest normal acid exposure on 24-h pH monitoring. Further, patients with NERD appear to be somewhat less responsive to gastric acid suppression with proton pump inhibitors. These differences, combined with the concept of the 'tender' oesophagus and the frequent presence of dyspeptic symptoms in patients with NERD, have important therapeutic implications. Therefore, considering the marked overlap in these disorders, is it realistic or clinically relevant to distinguish the entities of GORD, NERD, and functional dyspepsia? This dilemma has led to general guidelines: should heartburn predominate, treat as GORD; if dyspepsia predominates, treat as functional dyspepsia. In practical terms, each diagnosis requires consideration of the other.

Can symptoms predict esophageal motor function or acid exposure in gastroesophageal reflux disease? A comparison of esophageal manometric and twenty-four-hour pH parameters in typical and extraesophageal gastroesophageal reflux disease

It has been suggested that patterns of esophageal motor function and acid exposure may differ between those patients with gastroesophageal reflux disease (GERD) with classic symptoms and those with extraesophageal manifestations. Our objective was to compare various parameters of esophageal motility and acid exposure between groups of patients who had presented with extraesophageal manifestations of GERD alone, a combination of classic and extraesophageal manifestations, or classic GERD symptoms alone. A retrospective review of consecutive patients undergoing esophageal manometry and 24-hour dual-channel esophageal pH testing was performed. Information on patient demographics, symptoms, and results of various manometric and pH testing parameters was examined. We evaluated 84 patients: 32 with extraesophageal symptoms alone, 24 with both classic and extraesophageal symptoms, and 28 with classic symptoms alone. Apart from a trend toward less supine acid exposure in those with extraesophageal symptoms alone, no significant differences were evident among the three patient groups in any of the other parameters of proximal or distal esophageal acid reflux. With respect to motility parameters, lower esophageal sphincter pressure was lower in those with combined symptoms; otherwise, manometric findings were similar in the three patient groups. Our data do not support the hypothesis that the nature of the clinical presentation of GERD, whether in the form of classic or extraesophageal manifestations, is related to differing patterns of esophageal motor function or esophageal acid exposure.

Gastroduodenal motility

During the past year there were significant developments in the area of gastroduodenal motility--in basic physiology, pathophysiology, diagnosis, and therapy. Some represented a major breakthrough; most were incremental. Evidence continues to accumulate to support an important role for the stomach in the regulation of food intake, and the physiologic mechanisms involved continue to be revealed. Although there were no dramatic developments in the area of diagnostic methodology, several studies sought to refine or to extend the use of currently available techniques. Gastric motor activity and that of the proximal stomach continue to attract attention in dyspepsia and gastroesophageal reflux disease, and the range of disorders that may disrupt the motor function of the stomach continues to extend. On the therapeutic front, advances were largely in refining the indications and the uses of available therapies, rather than in the development of novel agents.

The effects of tegaserod (HTF 919) on oesophageal acid exposure in gastro-oesophageal reflux disease

BACKGROUND

Tegaserod (HTF 919), a 5-HT4 receptor partial agonist, has prokinetic effects that might be useful in decreasing acid reflux in gastro-oesophageal reflux disease (GERD).

METHODS

To investigate the potential clinical utility of tegaserod in GERD, a five-period crossover study (balanced Latin square) was designed to evaluate the efficacy of 4 b.d. doses of tegaserod vs. placebo. Four-hour manometry (1 h fasting and 3 h postprandial) with continuous recording of lower oesophageal sphincter pressure and distal oesophageal pH, was performed at the end of each 2-week treatment period in 19 patients with mild-to-moderate GERD. Recordings were scored for mean lower oesophageal sphincter pressure, number of transient lower oesophageal sphincter relaxations, and distal oesophageal acid exposure.

RESULTS

Tegaserod (1 mg/day and 4 mg/day) caused a more than 50% decrease in acid exposure in the postprandial period in patients with abnormal acid exposure, although only the 1 mg/day tegaserod treatment elicited statistically significant decreasing (P < 0.05) for the entire treatment group (percentage time for which pH < 4: placebo=13%; 1 mg/day dose=5%; 4 mg/day dose=8%). A decreased number of reflux episodes was demonstrated with both the 1 mg/day and 4 mg/day tegaserod doses. There was no apparent effect on mean lower oesophageal sphincter pressure, whilst transient lower oesophageal sphincter relaxations frequency decreased in the 1-2.5 h post-dose.

CONCLUSIONS

Tegaserod in a dose of 1 mg/day causes a significant decrease in postprandial oesophageal acid exposure. The reduction in oesophageal acid exposure with tegaserod treatment may result from enhanced oesophageal acid clearance, improved gastric emptying, and/or reduced transient lower oesophageal sphincter relaxations.

Pharmacotherapy of gastroparesis

The evaluation and management of gastric motor dysfunction continues to represent a significant clinical challenge. The very definition of what constitutes a clinically relevant disturbance of gastric motility remains unclear. The spectrum of gastroparesis extends from those with classical symptoms and severe delay of gastric emptying to those with dyspepsia and a mild delay in emptying rate. Indeed, for many patients with dyspepsia, the role of gastric emptying delay in the pathogenesis of symptoms, remains unclear. Any assessment of the efficacy of any therapeutic class in gastroparesis must be mindful, therefore, of these variations in definition. For those individuals with severe established gastroparesis, therapeutic success often remains elusive and i.v. erythromycin and oral dopamine antagonists, or substituted benzamides, remain the best options for acute severe exacerbations and chronic maintenance therapy, respectively. Alternatives, currently under investigation, include a number of 5-HT4 agonists, macrolides devoid of antibiotic activity, CCK antagonists and gastric electrical stimulation. Other novel approaches include strategies to address some of the regional abnormalities in gastric motor function that have been identified in some patients with dyspepsia.

Assessment of gastric emptying using a low fat meal: establishment of international control values

OBJECTIVE

The diagnosis of gastroparesis implies delayed gastric emptying. The diagnostic gold standard is scintigraphy, but techniques and measured endpoints vary widely among institutions. In this study, a simplified scintigraphic measurement of gastric emptying was compared to conventional gastric scintigraphic techniques and normal gastric emptying values defined in healthy subjects.

METHODS

In 123 volunteers (aged 19-73 yr, 60 women and 63 men) from 11 centers, scintigraphy was used to assess gastric emptying of a 99Tc-labeled low fat meal (egg substitute) and percent intragastric residual contents 60, 120, and 240 min after completion of the meal. In 42 subjects, additional measurements were taken every 10 min for 1 h. In 20 subjects, gastric emptying of a 99Tc-labeled liver meal was compared with that of the 99Tc-labeled low fat meal.

RESULTS

Median values (95th percentile) for percent gastric retention at 60, 120, and 240 min were 69% (90%), 24% (60%) and 1.2% (10%) respectively. A power exponential model yielded similar emptying curves and estimated T50 when using images only taken at 1, 2 and 4 h, or with imaging taken every 10 min. Gastric emptying was initially more rapid in men but was comparable in men and women at 4 h; it was faster in older subjects (p < 0.05) but was independent of body mass index.

CONCLUSIONS

This multicenter study provides gastric emptying values in healthy subjects based on data obtained using a large sample size and consistent meal and methodology. Gastric retention of >10% at 4 h is indicative of delayed emptying, a value comparable to those provided by more intensive scanning approaches. Gastric emptying of a low fat meal is initially faster in men but is comparable in women at 4 h; it is also faster in older individuals but is independent of body mass.

Probiotics: from myth to reality. Demonstration of functionality in animal models of disease and in human clinical trials

The enteric flora comprise approximately 95% of the total number of cells in the human body and are capable of eliciting immune responses while also protecting against microbial pathogens. However, the resident bacterial flora of the gastrointestinal tract (GIT) may also be implicated in the pathogenesis of several chronic conditions such as inflammatory bowel disease (IBD). The University College Cork-based Probiotic Research Group has successfully isolated and identified lactic acid bacteria (LAB) which exhibit beneficial probiotic traits. These characteristics include the demonstration of bile tolerance; acid resistance; adherence to host epithelial tissue; and in vitro antagonism of potentially-pathogenic micro-organisms or those which have been implicated in promoting inflammation. The primary objective of this report is to describe the strategy adopted for the selection of potentially effective probiotic bacteria. The study further describes the evaluation of two members of the resulting panel of micro-organisms (Lactobacillus salivarius subsp. salivarius UCC118 and Bifidobacterium longum infantis 35624) under in vitro conditions and throughout in vivo murine and human feeding trials. Specifically, an initial feeding study completed in Balb/c mice focused upon (i) effective delivery of the probiotic micro-organisms to the GIT and evaluation of the ability of the introduced strains to survive transit through, and possibly colonise, the murine GIT; (ii) accepting the complexity of the hostile GIT and faecal environments, development of a method of enumerating the introduced bacterial strains using conventional microbiological techniques; and (iii) assessment of the effects of administered bacterial strains on the numbers of specific recoverable indigenous bacteria in the murine GIT and faeces. Additional research, exploiting the availability of murine models of inflammatory bowel disease, demonstrated the beneficial effects of administering probiotic combinations of Lactobacillus salivarius UCC118 and Bifidobacterium longum infantis 35624 in prevention of illness-related weight loss. A further ethically-approved feeding trial, successfully conducted in 80 healthy volunteers, demonstrated that yoghurt can be used as a vehicle for delivery of Lactobacillus salivarius strain UCC118 to the human GIT with considerable efficacy in influencing gut flora and colonisation.

Gastroduodenal motility

Several major themes emerged over the past year in the area of gastroduodenal motility. Mostly, these themes represented extensions of research areas discussed in prior reviews in this series rather than the emergence of completely new concepts. Thus, for example, considerable emphasis has again been placed on regional gastric motor function in dyspepsia and on the role of fundic relaxation and accommodation, in particular. Not surprisingly, basic physiologic research has also shown a keen interest in the regulation of fundic relaxation. One new and exciting development is the recognition of the stomach's role in satiety. The spectrum of gastric motor dysfunction in diabetes mellitus continues to be explored, and the important role of hyperglycemia in regulating gastric function has been further emphasized. More data have been provided on noninvasive alternatives to gastric motor function testing, and several studies have looked at factors that may influence variability in these various tests. There have been few innovations over the past year in the therapeutic arena; rather, the indications and limitations of current therapies have been further developed.

Small-bowel motility disturbances: a comparison of small-bowel series and antroduodenal manometry

RATIONALE AND OBJECTIVES

The authors' purpose was to compare the findings of small-bowel series with those of antroduodenal manometry to determine whether normal findings from a small-bowel series would make it unnecessary to perform antroduodenal manometry.

MATERIALS AND METHODS

The findings from 33 small-bowel series performed on patients who had undergone antroduodenal manometry were retrospectively reviewed for abnormalities, including dilatation, transit time, fold thickening, and increased fluid. Antroduodenal manometry findings were classified into the following categories: normal, myopathy, neuropathy, obstructions, or nonspecific conditions.

RESULTS

Nine of 12 patients with specific abnormalities at antroduodenal manometry had abnormal results from the small-bowel series. Of seven patients with normal small-bowel series results, three had abnormal antroduodenal manometry results--two had previously undergone vagotomy with neuropathic changes and one had myopathic changes.

CONCLUSION

Small-bowel series and antroduodenal manometry are complementary examinations. Only a small number of patients with normal small-bowel series results will have abnormal results at antroduodenal manometry. A large number of patients with motility abnormalities have a combination of nonspecific changes, such as dilatation and increased fluid, at a small-bowel series.

Disturbances in small bowel motility

Recently, the small intestine has become the focus of investigation as a potential site of dysmotility in the irritable bowel syndrome (IBS). A number of motor abnormalities have been defined in some studies, and include 'clustered' contractions, exaggerated post-prandial motor response and disturbances in intestinal transit. The significance of these findings remains unclear. The interpretation of available studies is complicated by differences in subject selection, the direct influence of certain symptoms, such as diarrhoea and constipation, and the interference of compounding factors, such as stress and psychopathology. Dysmotility could also reflect autonomic dysfunction, disturbed CNS control and the response to heightened visceral sensation or central perception. While motor abnormalities may not explain all symptoms in IBS, sensorimotor interactions may be important in symptom pathogenesis and deserve further study.

Principles of applied neurogastroenterology: physiology/motility-sensation

Many of the symptoms characteristic of the functional gastrointestinal disorders (FGID) are consistent with dysfunction of the motor and/or sensory apparatus of the digestive tract. Those aspects of sensorimotor dysfunction most relevant to the FGID include alterations in: gut contractile activity; myoelectrical activity; tone and compliance; and transit, as well as an enhanced sensitivity to distension, in each region of the gastrointestinal tract. Assessment of these phenomena involves a number of techniques, some well established and others requiring further validation. Using such techniques, researchers have reported a wide range of alterations in sensory and in motor function in the FGID. Importantly, however, relationships between such dysfunction and symptoms have been relatively weak, and so the clinical relevance of the former remains unclear. Moreover, the proportions of patients in the various symptom subgroups who display dysfunction, and the extent and severity of their symptoms, require better characterization. On a positive note, progress is occurring on several fronts, especially in relation to functional dyspepsia and irritable bowel syndrome, and based on the data gathered to date, a number of areas where further advances are required can be highlighted.

Probiotics: from myth to reality. Demonstration of functionality in animal models of disease and in human clinical trials

The enteric flora comprise approximately 95% of the total number of cells in the human body and are capable of eliciting immune responses while also protecting against microbial pathogens. However, the resident bacterial flora of the gastrointestinal tract (GIT) may also be implicated in the pathogenesis of several chronic conditions such as inflammatory bowel disease (IBD). The University College Cork-based Probiotic Research Group has successfully isolated and identified lactic acid bacteria (LAB) which exhibit beneficial probiotic traits. These characteristics include the demonstration of bile tolerance; acid resistance; adherence to host epithelial tissue; and in vitro antagonism of potentially-pathogenic micro-organisms or those which have been implicated in promoting inflammation. The primary objective of this report is to describe the strategy adopted for the selection of potentially effective probiotic bacteria. The study further describes the evaluation of two members of the resulting panel of micro-organisms (Lactobacillus salivarius subsp. salivarius UCC118 and Bifidobacterium longum infantis 35624) under in vitro conditions and throughout in vivo murine and human feeding trials. Specifically, an initial feeding study completed in Balb/c mice focused upon (i) effective delivery of the probiotic micro-organisms to the GIT and evaluation of the ability of the introduced strains to survive transit through, and possibly colonise, the murine GIT; (ii) accepting the complexity of the hostile GIT and faecal environments, development of a method of enumerating the introduced bacterial strains using conventional microbiological techniques; and (iii) assessment of the effects of administered bacterial strains on the numbers of specific recoverable indigenous bacteria in the murine GIT and faeces. Additional research, exploiting the availability of murine models of inflammatory bowel disease, demonstrated the beneficial effects of administering probiotic combinations of Lactobacillus salivarius UCC118 and Bifidobacterium longum infantis 35624 in prevention of illness-related weight loss. A further ethically-approved feeding trial, successfully conducted in 80 healthy volunteers, demonstrated that yoghurt can be used as a vehicle for delivery of Lactobacillus salivarius strain UCC118 to the human GIT with considerable efficacy in influencing gut flora and colonisation.