Exercise induction of gut microbiota modifications in obese,non-obese and hypertensive rats

Background

Obesity is a multifactor disease associated with cardiovascular disorders such as hypertension. Recently, gut microbiota was linked to obesity pathogenesisand shown to influence the host metabolism. Moreover, several factors such as host-genotype and life-style have been shown to modulate gut microbiota composition. Exercise is a well-known agent used for the treatment of numerous pathologies, such as obesity and hypertension; it has recently been demonstrated to shape gut microbiota consortia. Since exercise-altered microbiota could possibly improve the treatment of diseases related to dysfunctional microbiota, this study aimed to examine the effect of controlled exercise training on gut microbial composition in Obese rats (n = 3), non-obese Wistar rats (n = 3) and Spontaneously Hypertensive rats (n = 3). Pyrosequencing of 16S rRNA genes from fecal samples collected before and after exercise training was used for this purpose.

Results

Exercise altered the composition and diversity of gut bacteria at genus level in all rat lineages. Allobaculum (Hypertensive rats), Pseudomonas and Lactobacillus (Obese rats) were shown to be enriched after exercise, while Streptococcus (Wistar rats), Aggregatibacter and Sutturella (Hypertensive rats) were more enhanced before exercise. A significant correlation was seen in the Clostridiaceae and Bacteroidaceae families and Oscillospira and Ruminococcus genera with blood lactate accumulation. Moreover, Wistar and Hypertensive rats were shown to share a similar microbiota composition, as opposed to Obese rats. Finally, Streptococcus alactolyticus, Bifidobacterium animalis, Ruminococcus gnavus, Aggregatibacter pneumotropica and Bifidobacterium pseudolongum were enriched in Obese rats.

Conclusions

These data indicate that non-obese and hypertensive rats harbor a different gut microbiota from obese rats and that exercise training alters gut microbiota from an obese and hypertensive genotype background.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-511) contains supplementary material, which is available to authorized users.     

Lipopolysaccharide pretreatment of the udder protects against experimental Escherichia coli mastitis

Exposure to pathogen-associated molecular patterns such as LPS can cause an immune refractory state in mammals known as endotoxin tolerance (ET), resulting in a decreased inflammatory response after pathogen contact. This ET concept was used to reduce the severity of an experimentally-induced clinical mastitis. Cows were pretreated with 1?μg LPS per udder quarter and challenged 72?h (group L72EC) or 240?h (group L240EC) later with 500 CFU Escherichia coli. Pretreated animals showed no leukopenia after challenge, no (L72EC), or only slightly (L240EC), elevated body temperature and significantly reduced systemic and local clinical scores compared with cows that were not pretreated. Whereas an increase of milk somatic cell count after the E. coli challenge was abrogated in L72EC animals, it was significantly delayed in the L240EC group. In both pretreated groups the bacterial load in milk was markedly reduced. Based on the expression of inflammation-related genes in lobulo-alveolar mammary tissue, the tolerizing effect of LPS pretreatment is based on the inhibited up-regulation of inflammatory (TNF-α, IL-6, CXCL8, CCL20) and anti-inflammatory genes (IL-10, IRAK-M). These findings indicate that the concept of ET may be usefully applied as mastitis prophylaxis facilitating a rapid response to microbial infection and avoiding dysregulated inflammation.     

Rapid accumulation of polymorphonuclear neutrophils in the Corpus luteum during prostaglandin F(2α)-induced luteolysis in the cow

Prostaglandin F(2α) (PGF(2α)) induces luteolysis within a few days in cows, and immune cells increase in number in the regressing corpus luteum (CL), implying that luteolysis is an inflammatory-like immune response. We investigated the rapid change in polymorphonuclear neutrophil (PMN) numbers in response to PGF(2α) administration as the first cells recruited to inflammatory sites, together with mRNA of interleukin-8 (IL-8: neutrophil chemoattractant) and P-selectin (leukocyte adhesion molecule) in the bovine CL. CLs were collected by ovariectomy at various times after PGF(2α) injection. The number of PMNs was increased at 5 min after PGF(2α) administration, whereas IL-8 and P-selectin mRNA increased at 30 min and 2 h, respectively. PGF(2α) directly stimulated P-selectin protein expression at 5-30 min in luteal endothelial cells (LECs). Moreover, PGF(2α) enhanced PMN adhesion to LECs, and this enhancement by PGF(2α) was inhibited by anti-P-selectin antibody, suggesting that P-selectin expression by PGF(2α) is crucial in PMN migration. In conclusion, PGF(2α) rapidly induces the accumulation of PMNs into the bovine CL at 5 min and enhances PMN adhesion via P-selectin expression in LECs. It is suggested that luteolytic cascade by PGF(2α) may involve an acute inflammatory-like response due to rapidly infiltrated PMNs.     

Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

Background  

In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in meso-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (Enterococcus faecalis) and of a Gram (-) bacterium (Escherichia coli). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.     

Lochial secretions of Escherichia coli- or Arcanobacterium pyogenes-infected bovine uteri modulate the phenotype and the functional capacity of neutrophilic granulocytes

It has been suggested that in cases of puerperal endometritis of cattle infected with Escherichia coli and Arcanobacterium pyogenes, the neutrophils are compromised in their defense capacity or downregulated functionally. In addition to direct bacterial effects, contents of lochial secretions and secreted products of locally activated polymorphonuclear neutrophilic granulocytes (PMNs) may also account for changes in function of freshly immigrating neutrophils. In this study, lochial secretions were obtained from healthy cows and from cows infected by E. coli or A. pyogenes. Separated uterine PMN of infected cows displayed an altered phenotype and function which correlated with the degree of bacterial contamination. Concurrently tested circulating PMN showed no such changes. Infected lochial secretions sterilized by filtration also changed the phenotype of blood PMN. Lochial secretions of healthy cows displayed only minor effects. The effects on PMN function in infected cows varied: ingestion was less affected, whereas generation of reactive oxygen species (ROS) was severely depressed. Concurrently tested purified bacterial products (solubles and fragments) of E. coli and A. pyogenes did not induce the phenotypical and functional changes observed in blood PMN. Since infected lochia also contained high numbers of immigrated and probably activated PMN, the influence of supernatants from phorbol myristate acetate-activated PMN were tested on freshly isolated blood PMN. Such supernatants also increased the expression of certain surface molecules and inhibited the ROS generation. Thus, reduced function and altered phenotypes of PMN which immigrate into the uteri of cows with bacterial endometritis is due not only to interactions with bacteria or bacterial products, but is also to the uterine milieu.     

Some immune parameters in carp cyprinus Carpio susceptible and resistant to the haemoflagellate Trypanoplasma borreli

The present study addresses aspects of the (specific) immune response of carp to the haemoflagellate Trypanoplasma borreli. Sera of resistant carp contained antibodies, which agglutinated the flagellates in vitro. When flagellates were incubated in fish sera from resistant carp, binding of antibodies to flagellates could be demonstrated by flow cytometry, and T. borreli were effectively killed. Heat-treatment of the sera prevented killing, indicating that complement activation is important for the control of a T. borreli infection. Sera of carp that were highly susceptible to infection with T. borreli contained no antibodies capable of binding to or killing the parasite. Furthermore, specific antibodies were not generated after experimental infection. This lack of antibody production in susceptible carp is not due to a general unresponsiveness of lymphoid cells, since peripheral blood leukocytes (PBL) from susceptible and resistant carp responded to mitogenic stimuli in vitro with lymphocyte proliferation in a similar manner. However, viable flagellates were significantly less able to stimulate proliferation of PBL from susceptible carp. In vitro-produced culture supernatants of freshly isolated PBL from both carp lines (but not those of head kidney cells) differentially modulated the mitogen-induced proliferation of PBL from susceptible and resistant carp. The supernatants enhanced the proliferation of leukocytes obtained from individuals from the same carp line, but suppressed the mitogen-induced proliferation of PBL from the other line tested. This indicates that lymphoid cells from susceptible and resistant carp differ in their spectrum of spontaneously produced immunomodulatory mediators. Whether this is decisive for a T. borreli-specific and successful immune response is discussed.     

Effect of hexavalent carcinogenic chromium on carp Cyprinus carpio immune cells

Chromium is widely used in industrial processes, and is released into aquatic environments by electroplating, tannery and textile industries. Fishes in natural waters or in aquaculture facilities supplied with these waters are exposed to chromium waste and are presumed to be affected by deposits. Herein, we examine the effect of hexavalent chromium on carp Cyprinus carpio derived immune cells. In vitro exposure of carp leukocytes to hexavalent chromium induced cytotoxicity, decreased mitogen-induced lymphocyte activation and phagocyte functions at concentrations between 2 and 200 micromol Cr l(-1). Neutrophils responded to chromium challenge by changes in cell shape together with reduced nitric oxide and reactive oxygen production. This occurred at much lower concentrations than for the cytotoxic effects seen in leukocyte cultures derived from peripheral blood or pronephros. In a similar way, activation of carp lymphocytes by pokeweed mitogen was reduced in a dose-dependent manner, while cytotoxic effects on non-activated lymphocytes were observed at much higher doses of 200 micromol Cr l(-1). Altered lymphocyte and neutrophil functions are considered to be responsible for decreased resistance to pathogens observed in fishes under chronic chromium challenge.     

Summary of the animal homologue section of HLDA8

Development of reagents against leukocyte differentiation antigens in veterinary immunology is slower compared to humans and mice. Cross-reactivity studies with monoclonal antibodies (mAb) generated against human molecules represent an excellent approach for the detection of new reagents for the minor characterised species. Three hundred seventy-seven commercially available mAb from different companies were tested for their reactivity with cells from 17 species--including non-human primates, ruminants, swine, horse, carnivores, rabbit, guinea pig, chicken and fish. In a first round of testing by flow cytometry (FCM) 182 mAb showed reactivity with atleast one of the species described above. Most of the cross-reactivity was found against non-human primate leukocytes, but also species in evolutionarily more distant from humans showed in some cases a clear staining pattern in flow cytometry (FCM). In a second round these FCM-results were confirmed by molecular analyses, by immunoprecipitation studies and analyses on transfectants. Interesting was the broad species-overlapping reactivity of mAb directed against CD9 (11 out of 17 species), CD11a (11/17), CD14 (11/17), CD18 (13/17), CD21 (7/17), CD29 (10/17), CD44 (13/17), CD45 (9/17), CD47 (10/17), and CD49d (13/17), CD61 (6/17), CD86 (7/17), CD91 (5/17), and CD172a (10/17), indicating evolutionary highly conserved epitopes on these surface molecules. Our results suggest the suitability of crossreactive mAb for the animal model studies. Moreover, these findings contribute to our understanding of the evolution of the immune system.