Bengt Jeppsson

Alteration of Intestinal Microflora Is Associated With Reduction in Abdominal Bloating and Pain in Patients With Irritable Bowel Syndrome

Alteration of intestinal microflora is associated with reduction in abdominal bloating and pain in patients with irritable bowel syndrome

A novel probiotic mixture exerts a therapeutic effect on experimental autoimmune encephalomyelitis mediated by IL-10 producing regulatory T cells.

Background Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system (CNS). One potential therapeutic strategy for MS is to induce regulatory cells that mediate immunological tolerance. Probiotics, including lactobacilli, are known to induce immunomodulatory activity with promising effects in inflammatory diseases. We tested the potential of various strains of lactobacilli for suppression of experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Methodology/Principal Findings The preventive effects of five daily-administered strains of lactobacilli were investigated in mice developing EAE. After a primary screening, three Lactobacillus strains, L. paracasei DSM 13434, L. plantarum DSM 15312 and DSM 15313 that reduced inflammation in CNS and autoreactive T cell responses were chosen. L. paracasei and L. plantarum DSM 15312 induced CD4+CD25+Foxp3+ regulatory T cells (Tregs) in mesenteric lymph nodes (MLNs) and enhanced production of serum TGF-β1, while L. plantarum DSM 15313 increased serum IL-27 levels. Further screening of the chosen strains showed that each monostrain probiotic failed to be therapeutic in diseased mice, while a mixture of the three lactobacilli strains suppressed the progression and reversed the clinical and histological signs of EAE. The suppressive activity correlated with attenuation of pro-inflammatory Th1 and Th17 cytokines followed by IL-10 induction in MLNs, spleen and blood. Additional adoptive transfer studies demonstrated that IL-10 producing CD4+CD25+ Tregs are involved in the suppressive effect induced by the lactobacilli mixture. Conclusions/Significance Our data provide evidence showing that the therapeutic effect of the chosen mixture of probiotic lactobacilli was associated with induction of transferable tolerogenic Tregs in MLNs, but also in the periphery and the CNS, mediated through an IL-10-dependent mechanism. Our findings indicate a therapeutic potential of oral administration of a combination of probiotics and provide a more complete understanding of the host-commensal interactions that contribute to beneficial effects in autoimmune diseases.

Lactobacillus plantarum 299v inhibits Escherichia coli-induced intestinal permeability.

The purpose of this work was to investigate whether a probiotic bacterium, Lactobacillus plantarum 299v, could affect Escherichia coli-induced passage of mannitol across the intestinal wall. Sprague-Dawley rats were pretreated for one week by either tube feeding with L. plantarum 299v twice daily, free access to L. plantarum 299v by adding the bacterium in the drinking water, or negative control receiving regular feeding. Intestinal segments were mounted in Ussing chambers and the mucosa was exposed to control medium, E. coli, and L. plantarum 299v (alone or together). [14C]Mannitol was added as a marker of intestinal permeability and samples were taken from the serosal side. E. coli exposure induced a 53% increase in mannitol passage across the intestinal wall (P < 0.05). One week of pretreatment with L. plantarum 299v in the drinking water abolished the E. coli-induced increase in permeability. Tube feeding for one week or short-term addition of L. plantarum 299v in the Ussing chambers had no effect on the permeability provoked by E. coli challenge. Notably, L. plantarum 299v itself did not change the intestinal passage of mannitol. These data demonstrate that pretreatment with L. plantarum 299v, which is a probiotic bacterium, protects against E. coli-induced increase in intestinal permeability, and that L. plantarum 299v alone has no influence on the intestinal permeability. Thus, this study supports the concept that probiotics may exert beneficial effects in the gastrointestinal tract.

Survival of Lactobacillus plantarum DSM 9843 (299v), and effect on the short-chain fatty acid content of faeces after ingestion of a rose-hip drink with fermented oats

In a controlled and randomised double-blind study, 26 healthy adult volunteers consumed, for 21 d, 400 ml of a rose-hip drink containing oats (0.7 g/100ml) fermented with Lactobacillus plantarum DSM 9843 (RHL; containing 5 x 10(7) cfu ml(-1)), and 22 volunteers in a second group the same amount of a pure rose-hip drink (RH). Significant increases in the total faecal concentration of carboxylic acids (P < 0.05 after 1 week and P < 0.01 after 3 weeks of intake), acetic acid (P < 0.01 after 3 weeks of intake) and propionic acid (P < 0.01 after 3 weeks of intake and P < 0.05 eight days after intake ceased) were recorded in the RHL group, indicating increased fermentation in the colon. In both groups a significant increase was obtained in the concentration of faecal lactic acid (P < 0.001 after 1 and 3 weeks of intake). No changes were seen in the concentration of faecal butyrate. The numbers of faecal bifidobacteria and lactobacilli increased significantly in both groups after 3 weeks of intake. Sulphite-reducing clostridia rapidly decreased in the group receiving the product with Lb. plantarum DSM 9843 after 1 week of intake, and then also in the pure rose-hip group after 3 weeks of intake. No changes were seen in the numbers of total anaerobes, gram-negative anaerobes or total aerobes during administration. Lb. plantarum DSM 9843 was recovered in faeces from all volunteers in the RHL group. Median amounts were 7.0 (5.0-8.8) log10 cfu g(-1) after one week of intake, and 6.7 (5.0-8.9) log10 cfu g(-1) after 3 weeks, respectively. The strain was still recovered from faeces of five volunteers 8 d after administration ceased (> 4.8 log10 cfu g(-1)). During the period of intake the volunteers in the RHL group experienced a significant increase in stool volume, a significant decrease in flatulence and slightly softer stools. Volunteers in the RH group experienced a slight but significant decrease in stool volume.

Thioacetamide- and Carbon Tetrachloride-Induced Liver Cirrhosis

Two methods of inducing liver cirrhosis in the rat were studied. Intragastric administration of CCl4 for 16 weeks according to Proctor and Chatamra was compared to the administration of thioacetamide in the drinking water (0.3 g/l) for the same period. CCl4 administration induced micronodular cirrhosis in 6/8 animals with a 27% mortality. Thioacetamide induced cirrhosis in 6/8 animals without mortality. The histologic pictures differed somewhat in that the CCl4 group exhibited more necrosis and cellular swelling while the thioacetamide group had more nuclear atypias and proliferation. Biochemically both groups had elevated plasma levels of aspartate aminotransferase. The lysosomal enzyme beta-hexosaminidase (beta-NAG) showed a transient increase in the thioacetamide animals, while beta-glucuronidase decreased. CCl4-induced cirrhosis led to an increase in beta-NAG. Plasma zinc decreased in both groups as well as liver zinc content in the CCl4 group, while there was a continuous elevation of liver zinc in the thioacetamide group. We conclude that oral administration of thioacetamide is a simple and reliable method of inducing experimental liver cirrhosis. The differences in histological appearances and some biochemical parameters may be caused by the different mechanisms of action of thioacetamide and CCl4.

Gastrointestinal Surface Protection and Mucosa Reconditioning

BACKGROUND There is increasing evidence that preservation of the ecology of the gastrointestinal tract and the surface protection system--surfactants, mucus, and fiber--is important for the outcome in postoperative trauma patients, patients after bone marrow and liver transplantation, and patients with HIV or AIDS. Approximately 50% of the nourishment of the small intestine and > 80% of the nourishment of the large intestine comes from the lumen. This is especially deleterious to the large intestine. Within less than a week of intestinal starvation--even in the presence of intense parenteral nutrition--a mucosal atrophy is observed, promoting translocation of potentially pathogenic microorganisms. Enteral nutrition is crucial to the outcome in many of these conditions. If however, such a nutrition is based on simple carbohydrates, peptides, amino acids, or fatty acids, most of the nutrition administered will be absorbed in the upper gastrointestinal tract. Complex fibers and proteins can be regarded as nutrients especially destined to the lower gastrointestinal tract. They are fermented by the probiotic flora, normally colonizing the colonic mucosa, and the necessary nutrients: short-chain fatty acids and amino acids such as arginine and glutamine are produced at the level of the colonic mucosa. Careless antibiotic treatment reduces or eliminates this flora, induces local mucosal starvation, and makes the patients vulnerable to opportunistic infections and microbial intestinal translocation. METHODS AND RESULTS In this review the role of the different ingredients of the surface protection system are discussed. A program to recondition the intestines, particularly the colonic mucosa by resupply of species-specific lactobacilli, surfactants, amino acids (especially glutamine), and oat fiber (beta-glucans) is suggested. Extensive experience in animal models and early experience in a patient population are summarized and discussed. Oat has been chosen as a substrate for fermentation because it contains 100 times more of membrane lipids (surfactants) than any other food, has a favorable amino acid pattern (rich in glutamine), and is rich in water-soluble, fermentable-fiber beta-glucans. More than 1000 isolates of human-specific lactobacilli have been studied. Some strains, especially those of plantarum type, have proven effective in colonizing the colonic mucosa, suppressing the potentially pathogenetic flora, and may have other probiotic effects as well. CONCLUSION A totally new enteral formula has been designed based on probiotic bacteria and fiber and aimed at colonizing the intestinal mucosa with a local probiotic effect and fermentation of fiber.

Critical role of CXC chemokines in endotoxemic liver injury in mice

Tissue accumulation of leukocytes constitutes a rate‐limiting step in endotoxin‐induced tissue injury. Chemokines have the capacity to regulate leukocyte trafficking. However, the role of CXC chemokines, i.e., macrophage inflammatory protein‐2 (MIP‐2) and cytokine‐induced neutrophil chemoattractant (KC), in leukocyte recruitment, microvascular perfusion failure, cellular injury, and apoptosis in the liver remains elusive. Herein, mice were challenged with lipopolysaccharide (LPS) in combination with D‐galactosamine, and intravital microscopy of the liver microcirculation was conducted 6 h later. It was found that immunoneutralization of MIP‐2 and KC did not reduce LPS‐induced leukocyte rolling and adhesion in postsinusoidal venules. In contrast, pretreatment with monoclonal antibodies against MIP‐2 and KC abolished (83% reduction) extravascular recruitment of leukocytes in the livers of endotoxemic mice. Notably, endotoxin challenge increased the expression of CXC chemokines, which was mainly confined to hepatocytes. Moreover, endotoxin‐induced increases of liver enzymes and hepatocellular apoptosis were decreased by more than 82% and 68%, respectively, and sinusoidal perfusion was restored in mice passively immunized against MIP‐2 and KC. In conclusion, this study indicates that intravascular accumulation of leukocytes in the liver is independent of CXC chemokines in endotoxemic mice. Instead, our novel data suggest that CXC chemokines are instrumental in regulating endotoxin‐induced transmigration and extravascular tissue accumulation of leukocytes. Indeed, these findings demonstrate that interference with MIP‐2 and KC functions protects against septic liver damage and may constitute a potential therapeutic strategy to control pathological inflammation in endotoxemia.

Modulation of the Effect of Dextran Sulfate Sodium-Induced Acute Colitis by the Administration of Different Probiotic Strains of Lactobacillus and Bifidobacterium

The pathogenic mechanism of inflammatory bowel diseases is not fully understood but colonic microflora including Lactobacillus and Bifidobacterium species may affect the induction of colonic inflammation. In this study the relative efficacy of different probiotic organisms in the prevention of colitis was compared in an induced rat colitis model. Three Lactobacillus strains and two Bifidobacterium strains were fed to Sprague–Dawley rats for 7 days prior to offering the rats 5% dextran sulfate sodium (DSS) in their drinking water to induce colitis and the administration of the probiotics continued for 7 days with the DSS. Colitis severity was assessed daily using a disease activity index (DAI). Samples were collected 7 days after colitis induction for intestinal bacterial flora and bacterial translocation. The DAI decreased significantly on days 4, 5, 6, and 7 in the Lactobacillusplantarum DSM 9843, Bifidobacterium sp. 3B1, and Bifidobacterium infantis DSM 15158 groups compared to the colitis control. It decreased significantly on days 5, 6, and 7 in the Bifidobacterium infantis DSM 15158 group compared to the Lactobacillus paracaesi DSM 13434 and Lactobacillus gasseri 5B3 groups. It also decreased significantly on day 7 in the L. plantarum DSM 9843 group compared to the L. gasseri 5B3 group. Bacterial translocation to the mesenteric lymph nodes decreased significantly in all treatment groups compared to the colitis control. Enterobacteriaceae bacterial translocation to the liver decreased in all treatment groups compared to the colitis control. Administration of certain strains of Lactobacillusand Bifidobacterium significantly improves the DAI and reduces bacterial translocation, and L. plantarum DSM 9843, Bifidobacterium sp. 3B1, and Bifidobacterium infantis DSM 15158 seem to have the best effect.

Platelets support pulmonary recruitment of neutrophils in abdominal sepsis

Objective: Recent findings indicate that platelets not only regulate thrombosis and hemostasis but may also be involved in proinflammatory activities. Herein, we hypothesized that platelets may play a role in sepsis by activating and priming circulating neutrophils for subsequent recruitment into the lung. Design: Prospective experimental study. Setting: University Hospital Research Unit. Subject: Male C57BL/6 mice. Interventions: Lung edema, bronchoalveolar infiltration of neutrophils, levels of myeloperoxidase, expression and function of membrane-activated complex-1 (Mac-1) on neutrophils and the CXC chemokines, macrophage inflammatory protein-2, and cytokine-induced neutrophil chemoattractant were determined after cecal ligation and puncture (CLP). Mice received a platelet-depleting antibody as well as antibodies directed against P-selectin glycoprotein-ligand-1 and Mac-1 before CLP induction. Measurements and Main Results: CLP caused significant pulmonary damage characterized by neutrophil infiltration, increased levels of CXC chemokines, and edema formation in the lung. Furthermore, CLP up-regulated Mac-1 expression on neutrophils and increased the number of neutrophils binding platelets in the circulation. Interestingly, depletion of platelets reduced CLP-induced edema and neutrophil recruitment in the bronchoalveolar space by >60%. Furthermore, depletion of platelets reduced Mac-1 expression on neutrophils. On the other hand, inhibition of P-selectin glycoprotein-ligand-1 abolished CLP-induced neutrophil–platelet aggregation but had no effect on neutrophil expression of Mac-1. Conclusions: These data demonstrate that platelets play a key role in regulating infiltration of neutrophils and edema formation in the lung via upregulation of Mac-1 in abdominal sepsis.

Mucosal in vitro permeability in the intestinal tract of the pig, the rat, and man: species- and region-related differences.

Background: The barrier properties of the gastrointestinal mucosa may be studied by measuring its permeability to different-sized marker molecules. Owing to difficulties in obtaining human tissue it is, however, often necessary to extrapolate findings from experimental animals to man. The aim of the present study was to compare regional intestinal mucosal permeability in man, the rat, and the pig, using the same marker molecules and in vitro technique. Methods: Segments from jejunum, ileum, colon, and rectum were mounted in Ussing diffusion chambers, and the mucosa-to-serosa passage of C-mannitol, fluorescein isothiocyanate (FITC)–dextran 4,400, a-lactalbumin, ovalbumin, and FITC–dextran 70,000 was studied.Results: Irrespective of species or intestinal region an inverse relationship between the molecular weight of the markers and the permeability was seen. The mannitol permeability was higher in the small intestine than in the colon in man, whereas the rat showed a higher permeability in the ileum than in the jejunum and colon. The FITC–dextran 4,400 permeability was higher in all intestinal regions in the rat than in man and the pig. The macromolecules showed low permeability with no regional differences. Conclusions: The results showed differences between intestinal regions and between species. Permeability data from the pig correlated fairly well with those of man, whereas the rat differed, making it difficult to extrapolate from the rat to man.BACKGROUND The barrier properties of the gastrointestinal mucosa may be studied by measuring its permeability to different-sized marker molecules. Owing to difficulties in obtaining human tissue it is, however, often necessary to extrapolate findings from experimental animals to man. The aim of the present study was to compare regional intestinal mucosal permeability in man, the rat, and the pig, using the same marker molecules and in vitro technique. METHODS Segments from jejunum, ileum, colon, and rectum were mounted in Ussing diffusion chambers, and the mucosa-to-serosa passage of 14C-mannitol, fluorescein isothiocyanate (FITC)-dextran 4,400, alpha-lactalbumin, ovalbumin, and FITC-dextran 70,000 was studied. RESULTS Irrespective of species or intestinal region an inverse relationship between the molecular weight of the markers and the permeability was seen. The mannitol permeability was higher in the small intestine than in the colon in man, whereas the rat showed a higher permeability in the ileum than in the jejunum and colon. The FITC-dextran 4,400 permeability was higher in all intestinal regions in the rat than in man and the pig. The macromolecules showed low permeability with no regional differences. CONCLUSIONS The results showed differences between intestinal regions and between species. Permeability data from the pig correlated fairly well with those of man, whereas the rat differed, making it difficult to extrapolate from the rat to man.