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.