Ketogenic Diet Has Moderate Effects on the Fecal Microbiota of Wild-Type Mice

The ketogenic diet (KD) is a high-fat, low-carbohydrate diet that has been reported to have neuroprotective effects. The health effects of KD might be linked to an altered gut microbiome, which plays a major role in host health, leading to neuroprotective effects via the gut-brain axis. However, results from different studies, most often based on the 16S rRNA gene and metagenome sequencing, have been inconsistent. In this study, we assessed the effect of a 4-week KD compared to a western diet (WD) on the colonic microbiome of female C57Bl/6J mice by analyzing fecal samples using fluorescence in situ hybridization. Our results showed distinct changes in the total number of gut bacteria following the 4-week KD, in addition to changes in the composition of the microbiome. KD-fed mice showed higher absolute numbers of Actinobacteria (especially Bifidobacteria spp.) and lower absolute levels of Proteobacteria, often linked to gut inflammation, in comparison with WD-fed mice. Furthermore, an increased abundance of the typically rare genus Atopobium was observed. These changes may indicate the possible anti-inflammatory effects of the KD. However, since the overall changes in the microbiota seem low, the KD effects might be linked to the differential abundance of only a few key genera in mice.

Bacterial Vaginosis-Vaginal Polymicrobial Biofilms and Dysbiosis

BACKGROUND

Bacterial vaginosis (BV) is the most common genital disease worldwide in women of sexually active age, with a prevalence of 23-29%. Its traditional definition as dysbiosis, i.e., a disruption of the normal balance of the vaginal microbiota, with a massive increase of facultative and obligate anaerobic bacteria (mainly Gardnerella spp.) and a loss of lactobacilli, accurately describes the change in the vaginal microbiota, but does not explain the underlying pathophysiology.

METHODS

This review is based on information in pertinent articles retrieved by a selective literature search and on the authors' own research findings.

RESULTS

Fluorescent in situ hybridization (FISH) has revealed Gardnerella spp.-dominated polymicrobial vaginal biofilm as a cause of ascending gynecologic and pregnancy-related infections, preterm birth, and infertility in patients with BV. The biofilm-induced disturbance of epithelial homeostasis favors co-infection with pathogens of sexually transmitted infection (STI). Standard antibiotic therapy is ineffective against biofilms, and there is thus a recurrence rate above 50%. The characteristic biofilm can be followed as a diagnostic marker and is considered evidence of sexual transmission when heterosexual couples and ejaculate samples are examined. FISH studies have shown that, in addition to biofilm-related vaginosis, there are other dysbiotic changes in the vaginal microbiota that have not yet been characterized in detail. It is therefore justified to speak of a "bacterial vaginosis syndrome."

CONCLUSION

The simplistic view of BV as dysbiosis, characterizable by microscopic reference methods, has so far led to inadequate therapeutic success. An evaluation of molecular genetic testing methods that would be suitable for routine use and the development of therapeutic agents that are effective against biofilms are urgently needed if the "bacterial vaginosis syndrome" is to be effectively treated.

Inflammatory invasion on human vaginal mucosa correlated with combined drug treatment and recurrence in recurrent vulvovaginal candidiasis

AIM

Recurrent vulvovaginal candidiasis (RVVC) is a chronic, difficult to treat vaginal infection, caused by Candida species, which affects women of all ages and ethnic and social background. Most RVVC studies use animal models, and there is still a lack of observation on human tissue samples and effective therapy to reduce recurrence.

MATERIALS AND METHODS

We observed CD163⁺ macrophages and NLRP3 expression by immunohistochemistry, also investigated bacteria and fungi co-invasion by fluorescence in situ hybridization from 144 human vaginal biopsy tissues (48 RVVC, 48 VVC, 48 healthy volunteers), and we also explored the effect of combining metronidazole in the treatment of RVVC.

RESULTS

A large number of neutrophils, lymphocytes and plasma cells infiltrated the mucosa, basement membrane and submucosa, accompanied by significantly overexpressed NLRP3 inflammasome. While CD163⁺ macrophages often infiltrated under the basement membrane in patients with RVVC, 29.2% of cases were found Gardnerella and fungi jointly invaded the vaginal mucosas. RVVC vaginal mucosal histopathology revealed mucosal inflammatory responses dominated by neutrophils, which may involve activation of NLRP3 and immune tolerance of M2 macrophages (CD163⁺ ). Fluconazole combined with metronidazole can achieve higher efficiency (95.8% vs. 70.8%) and reduce the recurrence rate more (8.3% vs. 37.5%) at 6-month follow-up.

CONCLUSION

Inflammatory invasion on human vaginal mucosa correlated with combined drug treatment and recurrence in RVVC. The combined medication will need to further evaluate in future.

Clue Cells and Pseudo Clue Cells in Different Morphotypes of Bacterial Vaginosis

Introduction

Clue cells (epithelial cells heavily covered with adherent bacteria) are an accepted clue to the diagnosis of bacterial vaginosis. However, the exact morphologic criteria of clue cells and bacterial adherence were never elaborated.

Materials and Methods

We investigated adhesive and cohesive patterns of main microbiota groups in vaginal discharge using fluorescence in situ hybridization (FISH). Samples from 500 women diagnosed with bacterial vaginosis and positive for clue cells with classic microscopy were collected from 42 gynecologic practices in Berlin and reexamined in our FISH laboratory for the spatial distribution of Bifidobacteriaceae, Gardnerella, Fannyhessea vaginae (Atopobium); low G+C (guanine+cytosine) bacteria, lactobacilli, Lactobacillus iners; Lactobacillus crispatus, Gamma-Proteobacteria; and Enterobacteriaceae, Prevotella–Bacteroides, Veillonella, and Coriobacterium groups.

Results

Bacterial taxa present in vaginal smears were not accidentally assembled according to their relative abundance but were built in group-specific distribution patterns, which can be well described by two features: cohesiveness to each other and adherence to epithelial cells. Accordingly, four patterns can be distinguished: dispersed (non-adherent bacteria), dispersed adherent bacteria, cohesive (non-adherent) bacteria, and cohesive adherent bacteria. Direct cohesive adherence to the epithelial cells representing true clue cells was unique for Gardnerella species and observed only in 56% of the investigated samples. In the remaining vaginal samples, the epithelial cells were mechanically entrapped in bacterial masses, and the composition was unrelated to the epithelial cell surface, building non-adherent pseudo clue cells. The proportion of women with true clue cells in their samples from different gynecologic practices varied from 19% to 80%.

Discussion

Taxon indifferent imaging is inadequate for the exact analysis of the microbial layer adjacent to the vaginal epithelial cells. Morphologically seen bacterial vaginosis is a mix of at least two different conditions: biofilm vaginosis and bacterial excess vaginosis.

Antimicrobial Susceptibility of Microbiota in Bacterial Vaginosis Using Fluorescence In Situ Hybridization

Background: Testing of antibiotic resistance of intact vaginal microbiota in pure culture is not feasible. METHODS: Metronidazole, antiseptic octenisept®, antimycotic ciclopirox, bacterial probiotic Lactobacillus crispatus, yeast probiotic Saccharomyces boulardii, Gardnerella-phage-endolysin named phagolysin and phagolysin in combination with probiotics were tested for bacteriolytic activity. Included were vaginal swabs from 38 random women with Amsel-confirmed bacterial vaginosis (BV). Test aliquots were incubated by 37° for 2 and 24 h. Gardnerella, low G+C, Atopobium, lactobacilli, Lactobacillus iners and crispatus, Prevotella-Bacteroides, and Gammaproteobacteria microbial groups were quantified using fluorescence in situ hybridization (FISH). Results: The probiotic strain Lactobacillus crispatus demonstrated the weakest bacteriolytical effects, followed by metronidazole. Both had no impact on Gardnerella species, instead lysing Prevotella-Bacteroides, Enterobacteriaceae (by L.crispatus) or LGC, Atopobium and Prevotella-Bacteroides (by metronidazole) groups of the microbiota. Cytolytic activity on Gardnerella was highly pronounced and increased from octenisept to ciclopirox, phagolysin, phagolysin with L.crispatus, being best in the combination of phagolysin with S.boulardii. Universally active ciclopirox and octenisept® suppressed nearly all microbial groups including those which are regarded as beneficial. Phagolysin had no effect on naturally occurring Lactobacillus crispatus. Conclusions: FISH susceptibility testing allows unique efficacy evaluation of individually adjusted topical therapy without microbial isolation facilitating optimal therapy choice.

Vulvovaginal candidiasis: histologic lesions are primarily polymicrobial and invasive and do not contain biofilms

BACKGROUND

The recent demonstration of a vaginal biofilm in bacterial vaginosis and its postulated importance in the pathogenesis of recurrent bacterial vaginosis, including relative resistance to therapy, has led to the hypothesis that biofilms are crucial for the development of vulvovaginal candidiasis. The histopathology and microbial architecture of vulvovaginal candidiasis have not been previously defined; neither has Candida, containing biofilm been reported in situ. The present study aimed at clarifying the histopathology of vulvovaginal candidiasis including the presence or absence of vaginal biofilm.

STUDY DESIGN

In a cross-sectional study, vaginal tissue biopsies were obtained from 35 women with clinically, microscopically, and culture-proven vulvovaginal candidiasis and compared with specimens obtained from 25 healthy women and 30 women with active bacterial vaginosis. Vaginal Candida infection was visualized using fluorescent in situ hybridization with ribosomal gene-based probes.

RESULTS

Candida microorganisms were confirmed in 26 of 35 biopsies obtained from women with vulvovaginal candidiasis; however, Candida containing biofilm were not detected in any of the cases. Histopathological lesions were exclusively invasive and accompanied by co-invasion with Gardnerella or Lactobacillus species organisms.

CONCLUSION

Histopathological lesions of vulvovaginal candidiasis are primarily invasive in nature and polymicrobial and do not resemble biofilms. The clinical significance of Candida tissue invasion is unknown.

Genetic Mouse Models with Intestinal-Specific Tight Junction Deletion Resemble an Ulcerative Colitis Phenotype

BACKGROUND AND AIMS

A key pathogenetic feature of ulcerative colitis [UC] is an intrinsic low mucus phosphatidylcholine[PC] content. Recently, a paracellular transport for PC across tight junctions[TJs] was described, suggesting TJ disturbance as a cause of diminished luminal PC transport. Therefore, we aimed to generate mutant mice with TJ deletion to evaluate whether a UC phenotype developed.

METHODS

CL57BL/6 control wild-type mice were compared to mutant mice with tamoxifen-induced villin-Cre-dependent intestinal deletion of kindlin 1 and 2.

RESULTS

Electron microscopy of mucosal biopsies obtained from both mutants before overt inflammation following only 2 days of tamoxifen exposure revealed a defective TJ morphology with extended paracellular space and, by light microscopy, expanded mucosal crypt lumina. PC secretion into mucus was reduced by >65% and the mucus PC content dropped by >50%, causing a >50 % decrease of mucus hydrophobicity in both mutants. Consequently, the microbiota was able to penetrate the submucosa. After 3 days of tamoxifen exposure, intestinal inflammation was present in both mutants, with loose bloody stools as well as macroscopic and histological features of colitis. Oral PC supplementation was able to suppress inflammation. By analogy, colonic biopsies obtained from patients with UC in remission also showed a defective epithelium with widened intercellular clefts, and enlarged crypt luminal diameters with functionally impaired luminal PC secretion.

CONCLUSIONS

Genetic mouse models with intestinal deletion of kindlin 1 and 2 resulted in TJ deletion and revealed pathophysiological features of impaired PC secretion to the mucus leading to mucosal inflammation compatible with human UC.

Reduced Mass and Diversity of the Colonic Microbiome in Patients with Multiple Sclerosis and Their Improvement with Ketogenic Diet

Background: Colonic microbiome is thought to be involved in auto-immune multiple sclerosis (MS). Interactions between diet and the colonic microbiome in MS are unknown.

Methods: We compared the composition of the colonic microbiota quantitatively in 25 MS patients and 14 healthy controls.Fluorescence in situ hybridization (FISH) with 162 ribosomal RNA derived bacterial FISH probes was used. Ten of the MS patients received a ketogenic diet for 6 months. Changes in concentrations of 35 numerically substantial bacterial groups were monitored at baseline and at 2, 12, and 23/24 weeks.

Results: No MS typical microbiome pattern was apparent.The total concentrations and diversity of substantial bacterial groups were reduced in MS patients (P < 0.001). Bacterial groups detected with EREC (mainly Roseburia), Bac303 (Bacteroides), and Fprau (Faecalibacterium prausnitzii) probes were diminished the most. The individual changes were multidirectional and inconsistent. The effects of a ketogenic diet were biphasic. In the short term, bacterial concentrations and diversity were further reduced. They started to recover at week 12 and exceeded significantly the baseline values after 23–24 weeks on the ketogenic diet.

Conclusions: Colonic biofermentative function is markedly impaired in MS patients.The ketogenic diet normalized concentrations of the colonic microbiome after 6 months.

Impact of humic acids on the colonic microbiome in healthy volunteers

AIM

To test the effects of humic acids on innate microbial communities of the colon.

METHODS

We followed the effects of oral supplementation with humic acids (Activomin^®) on concentrations and composition of colonic microbiome in 14 healthy volunteers for 45 d. 3 × 800 mg Activomin^® were taken orally for 10 d followed by 3 × 400 mg for 35 d. Colonic microbiota were investigated using multicolor fluorescence in situ hybridization (FISH) of Carnoy fixated and paraffin embedded stool cylinders. Two stool samples were collected a week prior to therapy and one stool sample on days 10, 31 and 45. Forty-one FISH probes representing different bacterial groups were used.

RESULTS

The sum concentration of colonic microbiota increased from 20% at day 10 to 30% by day 31 and remained stable until day 45 (32%) of humic acid supplementation (P < 0.001). The increase in the concentrations in each person was due to growth of preexisting groups. The individual microbial profile of the patients remained unchanged. Similarly, the bacterial diversity remained stable. Concentrations of 24 of the 35 substantial groups increased from 20% to 96%. Two bacterial groups detected with Bac303 (Bacteroides) and Myc657 (mycolic acid-containing Actinomycetes) FISH probes decreased (P > 0.05). The others remained unaffected. Bacterial groups with initially marginal concentrations (< 0.1 × 10⁹/mL) demonstrated no response to humic acids. The concentrations of pioneer groups of Bifidobacteriaceae, Enterobacteriaceae and Clostridium difficile increased but the observed differences were statistically not significant.

CONCLUSION

Humic acids have a profound effect on healthy colonic microbiome and may be potentially interesting substances for the development of drugs that control the innate colonic microbiome.

Lipocalin 2 Protects from Inflammation and Tumorigenesis Associated with Gut Microbiota Alterations

High mucosal and fecal concentrations of the antimicrobial siderophore-binding peptide Lipocalin-2 (Lcn2) are observed in inflammatory bowel disease. However, Lcn2 function in chronic intestinal inflammation remains unclear. Here, we demonstrate that Lcn2 protects from early-onset colitis and spontaneous emergence of right-sided colonic tumors resulting from IL-10 deficiency. Exacerbated inflammation in Lcn2(-/-)/Il10(-/-) mice is driven by IL-6, which also controls tumorigenesis. Lcn2(-/-)/Il10(-/-) mice exhibit profound alterations in gut microbial composition, which contributes to inflammation and tumorigenesis, as demonstrated by the transmissibility of the phenotype and protection conferred by antibiotics. Specifically, facultative pathogenic Alistipes spp. utilize enterobactin as iron source, bloom in Lcn2(-/-)/Il10(-/-) mice, and are sufficient to induce colitis and right-sided tumors when transferred into Il10(-/-) mice. Our results demonstrate that Lcn2 protects against intestinal inflammation and tumorigenesis associated with alterations in the microbiota.

Functional anatomy of the colonic bioreactor: Impact of antibiotics and Saccharomyces boulardii on bacterial composition in human fecal cylinders

Sections of fecal cylinders were analyzed using fluorescence in situ hybridization targeting 180 bacterial groups. Samples were collected from three groups of women (N=20 each) treated for bacterial vaginosis with ciprofloxacin+metronidazole. Group A only received the combined antibiotic regimen, whereas the A/Sb group received concomitant Saccharomyces boulardii CNCM I-745 treatment, and the A_Sb group received S. boulardii prophylaxis following the 14-day antibiotic course. The number of stool cylinders analyzed was 188 out of 228 in group A, 170 out of 228 in group A/Sb, and 172 out of 216 in group A_Sb. The colonic biomass was organized into a separate mucus layer with no bacteria, a 10-30μm broad unstirred transitional layer enriched with bacteria, and a patchy fermentative area that mixed digestive leftovers with bacteria. The antibiotics suppressed bacteria mainly in the fermentative area, whereas abundant bacterial clades retreated to the transitional mucus and survived. As a result, the total concentration of bacteria decreased only by one order. These effects were lasting, since the overall recovery of the microbial mass, bacterial diversity and concentrations were still below pre-antibiotic values 4 months after the end of antibiotic treatment. Sb-prophylaxis markedly reduced antibiotic effects and improved the recovery rates. Since the colon is a sophisticated bioreactor, the study indicated that the spatial anatomy of its biomass was crucial for its function.

Saccharomyces boulardii CNCM I-745 supports regeneration of the intestinal microbiota after diarrheic dysbiosis - a review

The probiotic medicinal yeast Saccharomyces cerevisiae HANSEN CBS 5926 (Saccharomyces boulardii CNCM I-745) is used for the prevention and treatment of diarrhea. Its action is based on multiple mechanisms, including immunological effects, pathogen-binding and antitoxinic effects, as well as effects on digestive enzymes. Correlated with these effects, but also due to its inherent properties, S. boulardii is able to create a favorable growth environment for the beneficial intestinal microbiota, while constituting extra protection to the host mucus layer and mucosa. This review focuses on the positive influence of S. boulardii on the composition of the intestinal microbiota. In a dysbiosis, as during diarrhea, the main microbial population (especially Lachnospiraceae, Ruminococcaceae, Bacteroidaceae, and Prevotellaceae) is known to collapse by at least one order of magnitude. This gap generally leads to transient increases in pioneer-type bacteria (Enterobacteriaceae, Bifidobacteriaceae, and Clostridiaceae). Several human studies as well as animal models demonstrate that treatment with S. boulardii in dysbiosis leads to the faster reestablishment of a healthy microbiome. The most relevant effects of S. boulardii on the fecal composition include an increase of short chain fatty acid-producing bacteria (along with a rise in short chain fatty acids), especially of Lachnospiraceae and Ruminococcaceae, as well as an increase in Bacteroidaceae and Prevotellaceae. At the same time, there is a suppression of pioneer bacteria. The previously observed preventive action of S. boulardii, eg, during antibiotic therapy or regarding traveler’s diarrhea, can be explained by several mechanisms, including a stabilizing effect on the healthy microbiota as well as possibly on the mucus layer. Several different dysbiotic situations could profit from the effects of S. boulardii CNCM I-745. Its additional potential lies in a general stabilization of the gut flora for at-risk populations. More studies are needed to explore the full potential of this versatile probiotic yeast.

Polymicrobial Gardnerella biofilm resists repeated intravaginal antiseptic treatment in a subset of women with bacterial vaginosis: a preliminary report

PURPOSE

Bacterial vaginosis is a recalcitrant polymicrobial biofilm infection that often resists standard antibiotic treatment. We therefore considered repeated treatment with octenidine, a local antiseptic that has previously been shown to be highly effective in several biofilm-associated infections.

METHODS

Twenty-four patients with recurrent BV were treated with a 7-day course of octenidine (octenidine dihydrochloride spray application with the commercial product Octenisept). In case of treatment failure or relapse within 6 months, patients were re-treated with a 28-day course of octenidine. In case of recurrence within 6 months after the second treatment course, patients were treated again with a 28-day course followed by weekly applications for 2 months. Treatment effect was evaluated by assessment of the presence of the biofilm on voided vaginal epithelial cells through fluorescence in situ hybridisation.

RESULTS

The initial cure rate following a 7-day course of octenidine was as high as 87.5%. The 6-month relapse rate was, however, as high as 66.6%. Repeated treatment for 28 days led to an overall cure rate of 75.0%; however, it was also associated with emergence of complete resistance to octenidine in a subset of women. The overall cure rate after three treatment courses with 1-year follow-up was 62.5 %, with 37.5 % of the patients showing complete resistance to octenidine.

CONCLUSION

Our preliminary results showed that octenidine dihydrochloride was initially highly effective, but the efficacy of repeated and prolonged treatment dropped quickly as challenge with the antiseptic rapidly led to bacterial resistance in a considerable subset of women.

Small intestinal permeability in older adults

It is not yet clear whether intestinal mucosal permeability changes with advancing age in humans. This question is of high importance for drug and nutrition approaches for older adults. Our main objective was to answer the question if small intestinal barrier integrity deteriorates with healthy aging. We conducted a cross‐sectional study including the pooled data of 215 nonsmoking healthy adults (93 female/122 male), 84 of whom were aged between 60 and 82 years. After a 12‐h fast, all participants ingested 10 g of lactulose and 5 g of mannitol. Urine was collected for 5 h afterwards and analyzed for test sugars. The permeability index (PI = lactulose/mannitol) was used to assess small intestinal permeability. Low‐grade inflammation defined by high‐sensitivity C‐reactive protein ≥1 mL/L and kidney function (estimated glomerular filtration rate) were determined in the older age group. The PI was similar in older compared to younger adults (P =0.887). However, the urinary recovery of lactulose and mannitol was lower in the older adults and this change was neither associated with urinary volume nor glomerular filtration rate. The PI was not significantly correlated with low‐grade inflammation or presence of noninsulin‐dependent type 2 diabetes. However, it significantly deteriorated in the copresence of both conditions compared to low‐grade inflammation alone (P =0.043) or type 2 diabetes alone (P =0.015). Small intestinal mucosal barrier does not deteriorate with age per se. But low‐grade inflammation coupled with minor disease challenges, such as type 2 diabetes, can compromise the small intestinal barrier.

Until now, it has not been clear if the small intestinal mucosal barrier deteriorates with age per se. We investigated the pooled data of 215 nonsmoking healthy adults, 84 of whom were aged between 60 and 82 years and found similar intestinal permeability results in all age classes. However, in participants with low‐grade inflammation coupled with type 2 diabetes the small intestinal integrity was compromised.

Infection through structured polymicrobial Gardnerella biofilms (StPM-GB)

BACKGROUND

We analysed data on bacterial vaginosis (BV) contradicting the paradigm of mono-infection.

METHODOLOGY

Tissues and epithelial cells of vagina, uterus, fallopian tubes and perianal region were investigated using fluorescence in situ hybridization (FISH) in women with BV and controls.

RESULTS

Healthy vagina was free of biofilms. Prolific structured polymicrobial (StPM) Gardnerella-dominated biofilm characterised BV. The intact StPM-Gardnerella-biofilm enveloped desquamated vaginal/prepuce epithelial cells and was secreted with urine and sperma. The disease involved both genders and occurred in pairs. Children born to women with BV were negative. Monotherapy with metronidazole, moxifloxacin or local antiseptics suppressed but often did not eradicate StPM-Gardnerella-biofilms. There was no BV without Gardnerella, but Gardnerella was not BV. Outside of StPM-biofilm, Gardnerella was also found in a subset of children and healthy adults, but was dispersed, temporal and did not transform into StPM-Gardnerella-biofilm.

CONCLUSIONS

StPM-Gardnerella-biofilm is an infectious subject. The assembly of single players to StPM-Gardnerella-biofilm is a not trivial every day process, but probably an evolutionary event with a long history of growth, propagation and selection for viability and ability to reshape the environment. The evolutionary memory is cemented in the structural differentiation of StPM-Gardnerella-biofilms and imparts them to resist previous and emerging challenges.

Common biostructure of the colonic microbiota in neuroendocrine tumors and Crohn's disease and the effect of therapy

BACKGROUND

The aims were to comparatively investigate the biostructure of colonic microbiota in patients with neuroendocrine tumors and Crohn's disease (CD) and to study the response of the microbiota to therapy.

METHODS

Sections of fecal cylinders from 66 patients with neuroendocrine tumors (NET; 25 foregut, 30 midgut, 11 hindgut), 50 patients with CD (Crohn's Disease Activity Index [CDAI] ≥150), and 30 patients with chronic idiopathic diarrhea seen at the Charité Hospital and 25 healthy controls were investigated using fluorescence in situ hybridization with probes specific for five bacterial groups: Faecalibacterium prausnitzii, Clostridium group XIVa / Roseburia group, Bacteroides, Enterobacteriaceae, and Bifidobacteriaceae.

RESULTS

We found a striking F. prausnitzii (Fprau) depletion in the stool of patients with NET of the midgut and patients with CD. The changes of the microbiota in the two other NET groups were uncharacteristic and similar to those observed in patients with chronic idiopathic diarrhea. Fprau depletion was reversible with chemotherapy and with interferon alpha-2b treatment in patients with midgut NET. Somatostatin analogs had no influence on Fprau concentrations.

CONCLUSIONS

Patients with NET and CD show similarities in their abnormalities of the fecal biostructure. Interferon alpha and systemic chemotherapy significantly improved the fecal biostructure in patients with midgut NET.

Positive effects of local therapy with a vaginal lactic acid gel on dysuria and E.coli bacteriuria question our current views on recurrent cystitis

OBJECTIVE

We tested the effect of vaginally applied lactic acid gel on symptoms and bacteriuria in acutely exacerbated recurrent Eschericia coli cystitis.

METHODS

Carnoy fixed samples of the morning urine from 20 women with a history of recurrent E.coli cystitis were prospectively investigated for bacteriuria using fluorescence in situ hybridization (FISH).

RESULTS

In 11/20 women with acute cystitis, the symptoms and bacteriuria were regressive with lactic acid gel treatment, without the need for antibiotic treatment. The complete regression of symptoms took between 1 week (7 women) and 4 weeks (4 women). In parallel with this regression, the microscopic shape of E.coli bacteria in these women changed from short rods to long curly filaments starting within the first days of therapy. The filamentous transformation affected 100% of the E.coli population in six women and at least 50% of E.coli population in five women and was not observed in urine samples from untreated women or in women without clinical response to lactic acid gel. This could not happen if the bladder was the origin of the infection.

CONCLUSIONS

A number of recurrent and probably acute cystitis is a local vagino-urethritis caused by an adhesive invasive E.coli biofilm of the vaginal surface.

Mucin depleted foci, colonic preneoplastic lesions lacking Muc2, show up-regulation of Tlr2 but not bacterial infiltration

Mucin depleted foci (MDF) are precancerous lesions of the colon in carcinogen-treated rodents and humans at high risk. Since MDF show signs of inflammation we hypothesized that the defective mucous production would expose them to the risk of being penetrated by intestinal bacteria, which can be sensed by Toll-like receptors (Tlrs) and activate inflammatory pathways. To verify this hypothesis we tested the expression of 84 genes coding for Tlrs and associated pathways using RT-qPCR in MDF (n = 7) from 1,2-dimethylhydrazine (DMH)-treated rats. Among the 84 tested genes, 26 were differentially expressed in MDF with 5 genes significantly up-regulated and 21 down-regulated when compared to the normal mucosa. Tlr2, as well as other downstream genes (Map4k4, Hspd1, Irak1, Ube2n), was significantly up-regulated. Among the genes regulating the NFkB pathway, only Map4k4 was significantly up-regulated, while 19 genes were not varied and 6 were down-regulated. Tlr2 protein was weakly expressed both in normal mucosa and MDF. To determine whether inflammation observed in MDF could be caused by bacteria contacting or infiltrating crypts, we performed fluorescence in situ hybridization (FISH) experiments with a rRNA universal bacterial probe. None of the 21 MDF tested, showed bacteria inside the crypts, while among the colonic tumors (n = 15), only one had very few bacteria on the surface and on the surrounding normal mucosa. In conclusion, the up-regulation of Tlr2 in MDF, suggests a link between this receptor and carcinogenesis, possibly related to a defective barrier function of these lesions. The data of FISH experiments do not support the hypothesis that inflammation in MDF and tumors is stimulated by bacterial infiltration.

Mucosal invasion by fusobacteria is a common feature of acute appendicitis in Germany, Russia, and China

BACKGROUND/AIM

To investigate the geographic occurrence of mucosa-invading Fusobacteria in acute appendicitis.

PATIENTS AND METHODS

Carnoy- and formalin-fixated appendices from Germany, Russia, and China were comparatively investigated. Bacteria were detected using fluorescent in situ hybridization. Cecal biopsies from patients with inflammatory bowel disease and other conditions were used as disease controls.

RESULTS

Fusobacteria represented mainly by Fusobacterium nucleatum were the major invasive component in bacterial infiltrates in acute appendicitis but were completely absent in controls. The occurrence of invasive Fusobacteria in Germany, Russia, and China was the same. The detection rate in Carnoy-fixated material was 70-71% and in formalin-fixated material was 30-36%.

CONCLUSIONS

Acute appendicitis is a polymicrobial infectious disease in which F. nucleatum and other Fusobacteria play a key role.

Necrotic enteritis due to simultaneous infection with Isospora suis and clostridia in newborn piglets and its prevention by early treatment with toltrazuril

In this study, 51 piglets originating from five different sows were included in the investigations. The animal source of all sows had a history of Clostridium perfringens type A (β2) infection. The piglets of three sows (n = 31) were experimentally infected with Isospora suis within the first 4 h after birth and were randomly assigned to the treatment group or the sham-dosing group. The piglets of the two remaining sows (n = 20) served as I. suis-uninfected controls. Twelve hours post-infection, the animals in the treatment group (n = 15) were treated with toltrazuril (20 mg/kg BW, Baycox® 5% suspension). During an observation period of 14 days faecal consistency, faecal oocyst counts, faecal germ counts, mortality, body weight development and clinical status were recorded. One piglet per study group and litter was necropsied, and intestinal tissue samples were taken for histopathological investigations and in situ hybridisation on study days (SDs) 3 and 14. I. suis-infected but untreated piglets showed clinical disease resulting in liquefaction of faeces and decreased body weight development. In 59.2% of the observations, I. suis-infected but untreated piglets showed abnormal faecal consistencies whereas only 12.0% or respectively 4.4% of the faecal samples had a pasty consistency in the I. suis-infected-treated or in the control animals. The mean body weight at the end of the study was 3.37 kg in the I. suis-infected but untreated piglets while the average body weight in the I. suis-infected-treated animals was calculated as 4.42 kg and the control animal's mean body weight was 4.45 kg. Moreover, mortality, occurring between SDs 8 and 14, in this study group was 38.5% (n = 5), with 30.8% (n = 4) died from necrotic enteritis. In contrast, no piglets died in the I. suis-uninfected control group or in the toltrazuril-treated study group. The results of this study corroborate the hypothesis that simultaneous infection with I. suis and C. perfringens type A soon after birth leads to distinct interactions between the two pathogens and result in an increase in clinical disease, mortality and metabolically active C. perfringens type A.

[Functional biostructure of colonic microbiota (central fermenting area, germinal stock area and separating mucus layer) in healthy subjects and patients with diarrhea treated with Saccharomyces boulardii]

The colonic content can be compared to a spatially structured high output bioreactor composed of three functionally different regions: a separating mucus layer, a germinal stock area, and a central fermenting area. The stool mirrors this structure and can be used for diagnosis in health and disease. In a first part, we introduce a novel method based on fluorescence in situ hybridization (FISH) of sections of punched-out stool cylinders, which allows quantitatively monitor microbiota in the mucus, the germinal stock and the central fermenting areas. in a second part, we demonstrate the practical implementation of this method, describing the biostructure of stool microbiota in healthy subjects and patients with chronic idiopathic diarrhea treated with Saccharomyces boulardii. Punched stool cylinders from 20 patients with chronic idiopathic diarrhea and 20 healthy controls were investigated using fluorescence in situ hybridization. Seventy-three bacterial groups were evaluated. Fluctuations in assembly of 11 constitutive bacterial groups were monitored weekly for 3 weeks prior to, 3 weeks during, and 3 weeks after oral Saccharomyces boulardii supplementation. Typical findings in healthy subjects were a 5-60 μm mucus separating layer; homogeneous distribution and fluorescence, high concentrations (>10 × 10(10) bacterial/mL) of the three habitual bacterial groups: Bacteroides, Roseburia and Faecalibacterium prausnitzii; and low concentrations of the occasional bacterial groups. The diarrhea could be described in terms of increased separating effort, purging, decontamination, bacterial substitution. Typical findings in diarrhea were: increased thickness of the protective mucus layer, its incorporation in the stool, absolute reduction in concentrations of the habitual bacterial groups, suppression of bacterial metabolism in the central fermenting area (hybridization silence), stratification of the stool structure by watery ingredients, and substitutive increase in the concentrations of occasional bacterial groups. The microbial and clinical symptoms of diarrhea were reversible with Saccharomyces boulardii therapy. The structure-functional analysis of stool microbiota allows to quantitatively monitor colonic malfunction and its response to therapy. Saccharomyces boulardii significantly improves the stool biostructure in patients with chronic idiopathic diarrhea and has no influence on the stool microbiota in healthy subjects.

Acute appendicitis is characterised by local invasion with Fusobacterium nucleatum/necrophorum

BACKGROUND

Acute appendicitis is a local intestinal inflammation with unclear origin. The aim was to test whether bacteria in appendicitis differ in composition to bacteria found in caecal biopsies from healthy and disease controls.

METHODS AND PATIENTS

We investigated sections of 70 appendices using rRNA-based fluorescence in situ hybridisation. Four hundred caecal biopsies and 400 faecal samples from patients with inflammatory bowel disease and other conditions were used as controls. A set of 73 group-specific bacterial probes was applied for the study.

RESULTS

The mucosal surface in catarrhal appendicitis showed characteristic lesions of single epithelial cells filled with a mixed bacterial population ('pinned cells') without ulceration of the surroundings. Bacteria deeply infiltrated the tissue in suppurative appendicitis. Fusobacteria (mainly Fusobacterium nucleatum and necrophorum) were a specific component of these epithelial and submucosal infiltrates in 62% of patients with proven appendicitis. The presence of Fusobacteria in mucosal lesions correlated positively with the severity of the appendicitis and was completely absent in caecal biopsies from healthy and disease controls. Main faecal microbiota represented by Bacteroides, Eubacterium rectale (Clostridium group XIVa), Faecalibacterium prausnitzii groups and Akkermansia muciniphila were inversely related to the severity of the disease. The occurrence of other bacterial groups within mucosal lesions of acute appendicitis was not related to the severity of the appendicitis. No Fusobacteria were found in rectal swabs of patients with acute appendicitis.

CONCLUSIONS

Local infection with Fusobacterium nucleatum/necrophorum is responsible for the majority of cases of acute appendicitis.

Gardnerella biofilm involves females and males and is transmitted sexually

OBJECTIVE

To study the incidence and distribution of adherent Gardnerella vaginalis.

METHODS

Bacteria adherent to desquamated epithelial cells in the urine were detected using fluorescence in situ hybridization (FISH). Urine from patients with bacterial vaginosis (BV, n = 20), their partners (n = 10) and different control populations (n = 344) including pregnant women and their partners, randomly selected populations of hospitalized man, women and children as also healthy controls was investigated.

RESULTS

Gardnerella was found in two different forms: cohesive and dispersed. In the cohesive form, Gardnerella were attached to the epithelial cells in groups of highly concentrated bacteria. In the dispersed form, solitary Gardnerella were intermixed with other bacterial groups. Cohesive Gardnerella was present in all patients with proven BV and their partners, in 7% of men and 13% of women hospitalized for reasons other than BV, in 16% of pregnant women and 12% of their male partners, and in none of the healthy laboratory staff or children. In sexual partners, occurrence of cohesive Gardnerella was clearly linked. Dispersed Gardnerella were found in 10-18% of randomly selected females, 3-4% of males and 10% of children and not sexually linked. In daily longitudinal investigations over 4 weeks no transition between cohesive and dispersed Gardnerella and vice versa was observed. Transmission of a cohesive Gardnerella strain could be followed retrospectively over 15 years using molecular genetic methods.

CONCLUSIONS

Cohesive Gardnerella biofilm is a distinct, clearly definable entity which involves both genders and is sexually transmitted. The correct name distinguishing it from symptom-defined conditions like BV should be gardnerellosis and for the bacterium Gardnerella genitalis.

Dissimilarity in the occurrence of Bifidobacteriaceae in vaginal and perianal microbiota in women with bacterial vaginosis

Recent data point at the similarity between the perianal and vaginal microflora in terms of Lactobacillus species involved. Bacterial vaginosis, the most common perturbation of the vaginal microflora involving primarily overgrowth of Gardnerella vaginalis, has also been suggested to involve a recto-vaginal pathway. We addressed this issue with regard to bacteria of the Bifidobacteriaceae family. In particular, we investigated the putative concordance of the presence of G. vaginalis and a series of Bifidobacteria between the perianal and vaginal microflora in 10 patients with bacterial vaginosis through multicolor fluorescence in situ hybridization analysis of desquamated epithelial cells. G. vaginalis was found in a biofilm mode of growth at the perianal and vaginal sites. In most women at least one of the following species was detected perianally: Bifidobacterium adolescentis, Bifidobacterium longum, Bifidobacterium breves, Bifidobacterium bifidum and Bifidobacterium catenulatum. At the vaginal site, none of these Bifidobacteria was found. We conclude that bacterial vaginosis does not occur as a result of simple growth per continuum of perianal bacteria. Only some species originating from the intestinal tract do display pronounced vaginotropism, like G. vaginalis, whereas many other species do not.

Mucosal flora in Crohn's disease and ulcerative colitis - an overview

The intestinal flora harbors varies pathogens. Clostridium perfringens (gas gangrene), Enterococci (endocarditis), Enterobacteriaceae (sepsis), Bacteroides (abscesses) are present in the large intestine of every healthy person in high concentrations. These bacteria are, however, separated from the colonic wall by an impenetrable mucus layer and are tolerated by the host. This separation is disturbed in patients with inflammatory bowel disease (IBD), where bacteria adhere to the mucosa and invade epithelial cells with concomitant inflammatory response. This chronic bowel inflammation can not subside as long as the mucus barrier remains defective. The inflammatory response interferes with the state of tolerance to the intestinal bacteria and leads to characteristic changes in the biostructure of the faecal microbiota. These changes in the biostructure of faecal microbiota are specific for active Crohn's disease and ulcerative colitis (UC) and can be longitudinally monitored. The reason for the defect of the mucus barrier in IBD patients is unclear. Epidemiologic studies indicate a negative role of western lifestyle and foods and document the rise in the incidence of IBD in the industrialized countries during the 20(th) century. In parallel to this, detergents were introduced in households and emulsifiers were increasingly added to food. The cleaning effect of these on the colonic mucus has to be investigated. The present contribution summarizes new data on the biostructure of the intestinal microbiota.

Bacterial overgrowth and inflammation of small intestine after carboxymethylcellulose ingestion in genetically susceptible mice

BACKGROUND

Detergents and emulsifiers added to food may destroy the mucus barrier, which normally isolates bacteria from the intestinal wall, and lead to chronic bowel inflammation in susceptible persons. We investigated the influence of 2% carboxymethylcellulose (CMC) on the biostructure of the intestinal microbiota in IL-10 gene-deficient mice.

METHODS

Twenty to 27-week-old IL-10 gene-deficient mice received either 2% CMC solution (n = 7) or water (n = 6) orally for 3 weeks. Intestinal bacteria were investigated using fluorescence in situ hybridization in paraffin-fixed sections of the intestine.

RESULTS

CMC-treated IL-10 gene-deficient mice demonstrated a massive bacterial overgrowth, distention of spaces between villi, with bacteria filling these spaces, adherence of bacteria to the mucosa, and migration of bacteria to the bottom of the crypts of Lieberkuehn. Leukocytes migrated into the intestinal lumen in 4 of the 7 CMC mice. The changes were similar to those observed in Crohn's disease in humans and were absent in control animals.

CONCLUSIONS

CMC induces bacterial overgrowth and small bowel inflammation in susceptible animals. Because of its ubiquity in products and its unrestricted use in food of the industrial world, CMC is an ideal suspect to account for the rise of IBD in the 20th century.

[Biomorphology of the Bacterial Invasion in Chronic pharyngotonsillitis ]

BACKGROUND

The study investigates whether relapses of chronicpharyngotonsillitis result from new infections caused by theoro-pharyngeal microbial flora or are reactivations of persistent bacterial infections of the tonsils.

METHODS

90 patients, who were surgically treated for chronicpharyngotonsillitis (age 13 months to 38 years, at least 5 episodes of disease and antibiotic treatment in the past) were included. The surgery was performed in the antibiotic- and symptom-free period (at least 6 weeks after the last exacerbation). Sections of tonsillar tissue were investigated for invasive bacteria using fluorescence in situ hybridization (FISH) with group and species-specific 15/23S RNA based probes.

RESULTS

Abundant foci of invasive bacteria were found in 86% of the resected tonsils, despite previous treatment with antibiotica and absent symptoms of ongoing infection. The diffuse infiltration of the tonsils was most predominant in the youger children. Local invasive processes such as abscesses, fissures filled with pus and superficial infiltration of the tonsillar epithelium were more typical for adults. All of the foci were polymicrobial and contained up to 10 different species or groups of bacteria. The local concentrations of invasive bacteria were up to 1012 bacteria/ml.

CONCLUSIONS

The chronic pharyngotonsillitis is the result of persistent invasive bacterial infections. The polymicrobial nature of the infectious foci enables them to resist the antibiotic treatment and to exacerbate afterwards. The surgical treatment is unavoidable as long as antibiotic treatment fails to clear the infection.

Observational study of children with aerophagia

Aerophagia is a rare disorder in children. The diagnosis is often delayed, especially when it occurs concomitantly with constipation. The aim of this report is to increase awareness about aerophagia. This study describes 2 girls and 7 boys, 2 to 10.4 years of age, with functional constipation and gaseous abdominal distention. The abdomen was visibly distended, nontender, and tympanitic in all. Documenting less distention on awakening helped to make the diagnosis. Air swallowing, belching, and flatulence were infrequently reported. The rectal examination often revealed a dilated rectal ampulla filled with gas or stool and gas. The abdominal X-ray showed gaseous distention of the colon in all and of the stomach and small bowel in 8 children. Treatment consisted of educating parents and children about air sucking and swallowing, encouraging the children to stop the excessive air swallowing, and suggesting to them not to use drinking straws and not to drink carbonated beverages. The aerophagia resolved in all in 2 to 20 months (mean=8 months).

Biostructure of fecal microbiota in healthy subjects and patients with chronic idiopathic diarrhea

BACKGROUND & AIMS

Dysbiosis is a key component of intestinal disorders. Our aim was to quantitatively access the biostructure of fecal microbiota in healthy subjects and patients with chronic idiopathic diarrhea and evaluate the responses to Saccharomyces boulardii treatment.

METHODS

We investigated punched fecal cylinders from 20 patients with chronic idiopathic diarrhea and 20 healthy controls using fluorescence in situ hybridization. Fluctuations in assembly of 11 bacterial groups were monitored weekly for 3 weeks before, during, and after oral S boulardii supplementation.

RESULTS

The structural organization of fecal microbiota in healthy subjects was stable and unaffected by S boulardii. The assembly of fecal microbiota in idiopathic diarrhea was markedly different, characterized by mucus depositions within feces; mucus septa and striae; marked reduction in concentrations of habitual Eubacterium rectale, Bacteroides, and Faecalibacterium prausnitzii groups; suppression of bacterial fluorescence in the center of the feces; increased concentrations and spatial shift of mucotrop bacteria to the fecal core; and increased concentrations of occasional bacteria. Except for elevated concentrations of some occasional bacterial groups, all parameters typical for diarrhea improved significantly with S boulardii treatment and most changes persisted after cessation of therapy. The improvement of the fecal microbiota was accompanied by partial (40%) and complete normalization (30%) of the diarrheal symptoms.

CONCLUSIONS

The fecal microbiota is highly structured. Fluorescence in situ hybridization analysis allowed us to quantitatively study the dysbiotic changes. S boulardii significantly improved the fecal biostructure in patients with diarrhea but had no influence on the feces in healthy subjects.

Active Crohn's disease and ulcerative colitis can be specifically diagnosed and monitored based on the biostructure of the fecal flora

BACKGROUND

The intestinal microflora is important in the pathogenesis of inflammatory bowel disease (IBD). The impact of its spatial organization on health and disease is unknown.

METHODS

We investigated sections of paraffin-embedded punched fecal cylinders. Fluctuations in spatial distribution of 11 bacterial groups were monitored in healthy subjects (n = 32), patients with IBD (n = 204), and other gastrointestinal diseases (n = 186) using fluorescence in situ hybridization (FISH).

RESULTS

The microbial structure differed in patients with Crohn's disease (CD), ulcerative colitis (UC), and healthy and disease controls. The profiles of CD and UC were distinctly opposite in 6 of 11 FISH probes used. Most prominent were a depletion of Faecalibacterium prausnitzii (Fprau<1 x 10(9)/mL) with a normal leukocyte count in CD and a massive increase of leukocytes in the fecal-mucus transition zone (>30 leukocytes/10(4) microm(2)) with high Fprau in patients with UC. These 2 features alone enabled the recognition of active CD (Crohn's Disease Activity Index [CDAI] >150) or UC (Clinical Activity Index [CAI] >3) with 79%/80% sensitivity and 98%/100% specificity. The mismatch in the sensitivity was mainly due to overlap between single IBD entities, and the specificity was exclusively due to the similarity of Crohn's and celiac disease. When inflammatory bowel disease (IBD) patients were pooled the sensitivity was 100% for severe disease, 84% for moderate activity, 72% for IBD with < or =12 months remission, and 24% for IBD with >12 months remission.

CONCLUSIONS

The fecal flora is highly structured and spatially organized. Diagnosing IBD and monitoring disease activity can be performed based on analysis of punched fecal cylinders independent from the patient's complaints.

An adherent Gardnerella vaginalis biofilm persists on the vaginal epithelium after standard therapy with oral metronidazole

OBJECTIVE

The purpose of this study was to determine the efficacy of standard treatment with oral metronidazole in the eradication of the bacterial vaginosis biofilm.

STUDY DESIGN

We conducted an interventional follow-up study in which 18 patients with bacterial vaginosis were treated with oral metronidazole during 1 week and subsequently had a single random follow-up assessment at 1-week intervals, up to 5 weeks, with 3 patients representing each point in time. Follow-up assessment included conventional scoring of the vaginal microflora and determination of bacterial biofilm characteristics on a vaginal biopsy through bacterial 16/23S recombinant DNA-based fluorescence in-situ hybridization.

RESULTS

Although all patients recovered, we consistently observed the resurgence with treatment cessation of a dense and active bacterial biofilm on the vaginal mucosa, primarily consisting of Gardnerella vaginalis and Atopobium vaginae.

CONCLUSION

A large reservoir of the core bacteria to bacterial vaginosis persists as a biofilm after metronidazole treatment.

Constipation as cause of acute abdominal pain in children

OBJECTIVE

To evaluate the causes of acute abdominal pain in a large academic pediatric primary care population.

STUDY DESIGN

The complete charts of 962 children, > or = 4 years old, who were seen for at least 1 health maintenance visit during a 6-month period, were reviewed retrospectively for complaints and cause of acute abdominal pain.

RESULTS

We found that 9% of the 962 children had a visit for acute abdominal pain, with significantly more girls (12%) than boys (5%) having this complaint. Acute and chronic constipation were the most frequent causes of acute abdominal pain, occurring in 48% of subjects. A surgical cause was present in 2% of subjects. The cause for the acute abdominal pain remained unknown in 19% of subjects. We did not find significant differences in diagnoses in the primary care clinics versus emergency department.

CONCLUSIONS

We found that constipation was the most common cause of acute abdominal pain in children.

Bacterial biofilm suppression with antibiotics for ulcerative and indeterminate colitis: consequences of aggressive treatment

BACKGROUND

Antibiotics are commonly used in inflammatory bowel disease (IBD). Little is known about their effect on the mucosal flora.

METHODS

The mucosal flora was investigated in colonoscopic biopsies from six groups of 20 IBD patients each. Patients were selected with regard to duration of/interval to combined metronidazole and ciprofloxacin therapy: group I patients with 1 day and group II with 7-14 days of antibiotic therapy, group III-V patients evaluated 1-4 weeks, 2-18 weeks, 26-36 weeks after cessation of antibiotic therapy, respectively. The control group VI included patients without antibiotic therapy. Thirty different fluorescent in situ hybridization (FISH) probes representative of the diversity of the human intestinal flora were applied to all specimens.

RESULTS

Bacteria adherent to mucosa could be seen exclusively in DAPI stain and were practically nonamenable to FISH probes in patients on antibiotics (0.001-3+/-0.001-5)x10(10)/mL. Occurrence and concentrations were significantly reduced in groups I and II as compared to untreated controls. The mucosal bacteria were significantly augmented after cessation of antibiotic therapy in group III (13.2+/-4.3) and group IV (5.8+/-2) but not in group V (1.1+/-0.8) as compared to group VI (0.5+/-0.4)x10(10)/mL. Neither Bacteroides nor Enterobacteriaceae groups were permanently suppressed by metronidazole-ciprofloxacin therapy.

CONCLUSIONS

The suppressing effects of antibiotics on the mucosal flora are accompanied by massive rebound effects. The concentrations of mucosal bacteria are dramatically increased as soon as 1 week after cessation of antibiotic therapy, remaining at a level that is at least one power higher over a period of 5 months as compared to the group without antibiotic treatment.

Altered intestinal function in patients with chronic heart failure

OBJECTIVES

We evaluated morphology and function of the gut in patients with chronic heart failure (CHF).

BACKGROUND

Intestinal translocation of bacterial endotoxin may contribute to the inflammatory state observed in patients with CHF. The morphology and function of the gut may be abnormal.

METHODS

We studied 22 patients with CHF (age 67 +/- 2 years, left ventricular ejection fraction [LVEF] 31 +/- 1%, New York Heart Association functional class 2.3 +/- 0.1, peak VO2 15.0 +/- 1.0 ml/kg/min) and 22 control subjects (62 +/- 1 years, LVEF 68 +/- 2%, peak VO2 24.7 +/- 1.3 ml/kg/min). Bowel wall thickness was assessed by transcutaneous sonography, small intestinal permeability by the lactulose-mannitol test, passive carrier-mediated transport by D-xylose test, large intestinal permeability by sucralose test (5- and 26-h urine collection, high-performance liquid chromatography), and mucosal bacterial biofilm by fluorescence in situ hybridization in biopsies taken during sigmoidoscopy.

RESULTS

Chronic heart failure patients, compared with control patients, showed increased bowel wall thickness in the terminal ileum (1.48 +/- 0.16 mm vs. 1.04 +/- 0.08 mm), ascending colon (2.32 +/- 0.18 mm vs. 1.31 +/- 0.14 mm), transverse colon (2.19 +/- 0.20 vs. 1.27 +/- 0.08 mm), descending colon (2.59 +/- 0.18 mm vs. 1.43 +/- 0.13 mm), and sigmoid (2.97 +/- 0.27 mm vs. 1.64 +/- 0.14 mm) (all p < 0.01). Chronic heart failure patients had a 35% increase of small intestinal permeability (lactulose/mannitol ratio: 0.023 +/- 0.001 vs. 0.017 +/- 0.001, p = 0.006), a 210% increase of large intestinal permeability (sucralose excretion: 0.62 +/- 0.17% vs. 0.20 +/- 0.06%, p = 0.03), and a 29% decrease of D-xylose absorption, indicating bowel ischemia (26.7 +/- 3.0% vs. 37.4 +/- 1.4%, p = 0.003). Higher concentrations of adherent bacteria were found within mucus of CHF patients compared with control subjects (p = 0.007).

CONCLUSIONS

Chronic heart failure is a multisystem disorder in which intestinal morphology, permeability, and absorption are modified. Increased intestinal permeability and an augmented bacterial biofilm may contribute to the origin of both chronic inflammation and malnutrition.

Escherichia coli isolated from a Crohn's disease patient adheres, invades, and induces inflammatory responses in polarized intestinal epithelial cells

Inflammatory diseases of the intestinal tract are a major health concern both in the United States and around the world. Evidence now suggests that a new category of Escherichia coli, designated Adherent Invasive E. coli (AIEC) is highly prevalent in Crohn's Disease (CD) patients. AIEC strains have been shown to colonize and adhere to intestinal epithelial cells (IEC). However, the role AIEC strains play in the induction of an inflammatory response is not known. Therefore, we examined several E. coli strains (designated LF82, O83:H1, 6604 and 6655) that were isolated from CD patients for their ability to induce inflammation in two IEC, Caco-2BBe and T-84 cells. Results showed that each strain had varying abilities to adhere to and invade IEC as well as induced cytokine secretion from polarized IEC. However, E. coli O83:H1 displayed the best characteristics of AIEC strains as compared to the prototype AIEC strain LF82, inducing cytokine secretion from IEC and promoting immune cell migration through IEC. Upon further analysis, E. coli O83:H1 did not harbor virulence genes present in known pathogenic intestinal organisms. Further characterization of E. coli O83:H1 virulence determinants showed that a non-flagellated O83:H1 strain significantly decreased the organism's ability to adhere to and invade both IEC and elicit IEC cytokine secretion compared to the wild type and complemented strains. These findings demonstrate that E. coli O83:H1 possesses the characteristics of the AIEC LF82 strain that may contribute to the low-grade, chronic inflammation observed in Crohn's disease.

Viscosity gradient within the mucus layer determines the mucosal barrier function and the spatial organization of the intestinal microbiota

BACKGROUND

Migration is an important virulence factor for intestinal bacteria. However, the role of bacterial mobility in the penetration of viscous mucus and their spatial organization within the colon is relatively unknown.

METHODS

Movements of fecal bacteria were assessed in gels of varying agarose concentrations and were compared with patterns of bacterial distribution observed in colons from conventional and Enterobacter cloacae-monoassociated mice. Bacteria were visualized using fluorescence in situ hybridization.

RESULTS

Long curly bacteria moved best in moderate viscosity gels, short rods and cocci preferred a low viscous environment, whereas high viscosity immobilized all bacterial groups. The spatial distribution of bacteria in the murine colon was also shape- and not taxonomy-dependent, indicating the existence of vertical (surface to lumen) and longitudinal (proximal to distal colon) viscosity gradients within the mucus layer. Our results suggest that mucus viscosity is low in goblet cells, at the crypt basis and close to the intestinal lumen, whereas sites adjacent to the columnar epithelium have a high mucus viscosity. The mucus viscosity increased progressively toward the distal colon, separating bacteria selectively in the proximal colon and completely in the distal colon.

CONCLUSIONS

The site-specific regulation of mucus secretion and dehydration make the mucus layer firm and impenetrable for bacteria in regions close to the intestinal mucosa but loose and lubricating in regions adjacent to the luminal contents. Selective control of mucus secretion and dehydration may prove to be a key factor in the management of chronic diseases in which intestinal pathogens are involved.

Comparative study of the intestinal mucus barrier in normal and inflamed colon

AIM

To study the role of mucus in the spatial separation of intestinal bacteria from mucosa.

PATIENTS AND METHODS

Mucus barrier characteristics were evaluated using histological material obtained by biopsy from purged colon, colon prepared with enema and material from untreated appendices fixed with non-aqueous Carnoy solution. Bacteria were evaluated using fluorescence in situ hybridization, with bacterial 16S RNA probes and related to the periodic acid Schiff alcian blue stain. Biopsies from controls (n = 20), patients with self-limiting colitis (SLC; n = 20), ulcerative colitis (n = 20) and 60 randomly selected appendices were investigated.

RESULTS

The mucosal surface beneath the mucus layer was free of bacteria in > or =80% of the normal appendices and biopsies from controls. The thickness of the mucus layer and its spread decreased with increasing severity of the inflammation; the epithelial surface showed bacterial adherence, epithelial tissue defects and deep mucosal infiltration with bacteria and leucocytes. Bacteria and leucocytes were found within mucus in all biopsy specimens from patients with ulcerative colitis, SLC, and acute appendicitis. The concentration of bacteria within mucus was inversely correlated to the numbers of leucocytes.

CONCLUSIONS

The large bowel mucus layer effectively prevents contact between the highly concentrated luminal bacteria and the epithelial cells in all parts of the normal colon. Colonic inflammation is always accompanied by breaks in the mucus barrier. Although the inflammatory response gradually reduces the number of bacteria in mucus and faeces, the inflammation itself is not capable of preventing bacterial migration, adherence to and invasion of the mucosa.

Effects of the Angiotensin II Type 1 Receptor Antagonist Telmisartan on Monocyte Adhesion and Activation in Patients with Essential Hypertension

Circulating monocytes from hypertensive patients show elevated secretion patterns of pro-inflammatory cytokines, an increased expression of adhesion molecules, and an increased adhesion to vascular endothelial cells. We tested the hypothesis that telmisartan, an angiotensin II type 1 (AT(1)) receptor antagonist, reduces the activation of circulating monocytes from hypertensive patients and diminishes the monocyte-endothelial cell adhesion. Monocytes of 20 hypertensive patients and 20 normotensive controls were isolated by density gradient centrifugation and Dynabeads, and the monocyte adhesion to human aortic endothelial cell monolayers was measured by adhesion assays. To characterize monocyte activation we assessed the expression of activity-related cell surface markers that are also involved in monocyte adhesion to endothelial cells, such as CD11a/b and CD54, as well as the chemokine receptors CCR1, CCR2 and CCR5 before and after telmisartan therapy using flow cytometry. Spontaneous adhesion of monocytes from hypertensive patients and the adhesion after stimulation with angiotensin II were significantly increased compared with those in normotensive controls (p<0.05). Treatment of hypertensive patients with the AT(1) receptor antagonist telmisartan significantly diminished the adhesion of circulating monocytes to human endothelial cells (p=0.02) despite the increase in the expressions of CD11b, CD54 and CCR5 after telmisartan therapy. Reducing monocyte adhesion may be a novel beneficial effect of the AT(1) receptor antagonist telmisartan helping to prevent vascular alterations in hypertension. The mechanism of action remains to be elucidated, since reduction in monocyte adhesion was not attributable to changes in adhesion molecule expression.

Azathioprine and mesalazine-induced effects on the mucosal flora in patients with IBD colitis

BACKGROUND

The impact of azathioprine and 5-aminosalicylic acid (5-ASA) on the innate immunity and mucosal flora is unknown. The study investigated the influence of IBD treatment on the concentrations and spatial organization of mucosal bacteria using fluorescence in situ hybridization with 16s r-RNA targeting probes.

METHODS

We prospectively investigated colonoscopic biopsies from five groups of 20 subjects each: patients with ulcerative or indeterminate colitis treated with azathioprine (group 1), azathioprine and 5-ASA (group 2), 5-ASA (group 3), untreated IBD (group 4), and healthy controls.

RESULTS

The elevated numbers of leukocytes in mucus of IBD patients were reduced nearly to norm in patients treated with azathioprine alone. In contrast, 5-ASA therapy had no influence on mucus leukocyte migration and was associated with the lowest concentrations of mucosal bacteria of all IBD groups. The suppressed migration of leukocytes in azathioprine-treated patients was accompanied by a 28-fold higher concentration of mucosal bacteria when compared with the 5-ASA group or a 1000-fold increase when compared with healthy controls. The percent of the epithelial surface covered with adherent bacteria (P < 0.001) and the amenability of mucosal bacteria (P = 0.01) were also significantly increased in the azathioprine-treated group compared with all other IBD groups. The patients receiving both 5-ASA and azathioprine did not differ statistically from untreated IBD patients either in mucus leukocyte migration or in bacterial concentrations.

CONCLUSIONS

Azathioprine and 5-ASA induce opposite effects on the mucus barrier. Concomitant therapy of 5-ASA and azathioprine mutually neutralizes the effects of both on the mucosal flora and the barrier function.