Inflammation-relevant microbiome signature of the stroke brain, gut, spleen, and thymus and the impact of exercise.

Stroke remains a significant unmet need in the clinic with few therapeutic options. We, and others, have implicated the role of inflammatory microbiota in stroke secondary cell death. Elucidating this inflammation microbiome as a biomarker may improve stroke diagnosis and treatment. Here, adult Sprague-Dawley rats performed 30 minutes of exercise on a motorized treadmill for 3 consecutive days prior to transient middle cerebral artery occlusion (MCAO). Stroke animals that underwent exercise showed 1) robust behavioral improvements, 2) significantly smaller infarct sizes and increased peri-infarct cell survival and 3) decreasing trends of inflammatory microbiota BAC303, EREC482, and LAB158 coupled with significantly reduced levels of inflammatory markers ionized calcium binding adaptor molecule 1, tumor necrosis factor alpha, and mouse monoclonal MHC Class II RT1B in the brain, gut, spleen, and thymus compared to non-exercised stroke rats. These results suggest that a specific set of inflammatory microbiota exists in central and peripheral organs and can serve as a disease biomarker and a therapeutic target for stroke.

The effects of feed naturally contaminated with Fusarium mycotoxins on the thymus in suckling piglets.

In this study, feed naturally containing Fusarium mycotoxins was fed to gilts during the perinatal period, and the effects on the thymus were investigated in one-week-old piglets. Twenty gilts were divided into equal control (0.26 mg deoxynivalenol, DON) and experimental (5.08 mg DON, 0.09 mg zearalenone and 21.61 mg fusaric acid per kg of feed) groups. One suckling piglet from each litter (n = 20) was sacrificed at one week of age to obtain thymus samples for further analysis. The cortex to medulla ratio of the thymus was morphometrically analysed using NIS Elements BR (Nikon) software. Paraffin-embedded thymus sections were stained to quantify apoptosis (with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling - TUNEL method), cellular proliferation (Ki-67) and macrophages (MAC 387). The results showed that the thymus cortex (P = 0.023) to medulla (P = 0.023) ratio was significantly lower in the experimental group. The number of apoptotic cells (cortex, P = 0.010, medulla, P = 0.001) and the number of proliferating cells in the thymus cortex (P = 0.001) and medulla (P < 0.001) were significantly higher in the experimental group. Our results indicate that feeding Fusarium mycotoxins to a parent animal during the perinatal period induces significant alterations in the thymus of one-week-old piglets, which indicates an immunosuppressive effect in piglets.

Paracoccidioides brasiliensis infection promotes thymic disarrangement and premature egress of mature lymphocytes expressing prohibitive TCRs.

BACKGROUND: Paracoccidioidomycosis, a chronic granulomatous fungal disease caused by Paracoccidioides brasiliensis yeast cells affects mainly rural workers, albeit recently cases in immunosuppressed individuals has been reported. Protective immune response against P. brasiliensis is dependent on the activity of helper T cells especially IFN-γ-producing Th1 cells. It has been proposed that Paracoccidioides brasiliensis is able to modulate the immune response towards a permissive state and that the thymus plays a major role in it. METHODS: In this paper, we show that acute infection of BALB/c mice with P. brasiliensis virulent isolate (Pb18) might cause alterations in the thymic environment as well as the prohibitive TCR-expressing T cells in the spleens. RESULTS: After seven days of infection, we found yeast cells on the thymic stroma, the thymic epithelial cells (TEC) were altered regarding their spatial-orientation and inflammatory mediators gene expression was increased. Likewise, thymocytes (differentiating T cells) presented higher migratory ability in ex vivo experiments. Notwithstanding, P. brasiliensis-infected mice showed an increased frequency of prohibitive TCR-expressing T cells in the spleens, suggesting that the selection processes that occur in the thymus may be compromised during the acute infection. CONCLUSION: In this paper, for the first time, we show that acute infection with Paracoccidioides brasiliensis yeast cells promotes thymic alterations leading to a defective repertoire of peripheral T cells. The data presented here may represent new mechanisms by which P. brasiliensis subverts the immune response towards the chronic infection observed in humans.

Beneficial bacteria inhibit cachexia.

Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny.

Presence of toll like receptor-2 in spleen, lymph node and thymus of Swiss albino mice and its modulation by Staphylococcus aureus and bacterial lipopolysaccharide. .

Toll-like receptors (TLR) are a family of pattern recognition receptors identifying pathogen associated molecular patterns (PAMPs). They play a critical role in the innate immune response during the initial interaction between the infecting microorganism and phagocytic cells. Here, we verified the presence of TLR-2 in spleen, lymph node and thymus of Swiss albino mice and their modulation after infection with Staphylococcus aureus and Lipopolysaccharide (LPS) challenge. It was seen that TLR-2 gene transcribed to its respective mRNA on S. aureus infection, in thymus, spleen and lymph node of mice but their levels and mode of expression varied. When challenged with LPS no prominent changes in the expression of TLR-2 receptor was observed but its expression increased gradually with time in the thymus, spleen and lymph node of S. aureus infected mice. TLR-2 expression was also found enhanced in infected splenic macrophages. By studying the serum cytokine profile the functionality of the receptor was measured. The results indicate the presence of TLR-2 in thymus, spleen and lymph node of Swiss albino strain of mice and that they are modulated by S. aureus.

Tuberculosis of the thymus in a 6-month-old infant with literature review.

Tuberculosis of the thymus is very uncommon. Most previously reported cases have involved adolescents or adults. Herein, we report a case of tuberculosis of the thymus diagnosed in a 6-month-old infant, presenting with progressive dyspnea and a mediastinal mass. Both clinical and radiologic findings were nonspecific, while pathologic findings confirmed thymic tissue with massive caseous granulomas consistent with tuberculosis.

Dynamics of the systemic components of the chicken (Gallus gallus domesticus) immune system following activation by Escherichia coli; implications for the costs of immunity.

The immune response is thought to be costly and deters from growth and reproduction, but the magnitude and sources of these costs are unknown. Thus, we quantified the changes in mass of leukocytes (CD4(+) and CD8(+) T cells, Bu1(+) IgM(+) and Bu1(+) IgG(+) B cells, monocytes/macrophages, heterophils and thrombocytes) and protective plasma proteins in systemic (non-mucosal) components of adult chickens injected intravenously with dead Escherichia coli. During the first day after E. coli injection most types of blood leukocytes decreased and α-1-acid glycoprotein increased. Specific IgM, specific IgY, total IgM, Bu1(+) lymphocytes in the spleen and bone marrow and thymic CD8(+) lymphocytes increased at 5d post-injection. Quantitatively, the increases in the weight of cells and antibodies due to E. coli were dwarfed by the increase in the weight of the liver and acute phase proteins. Thus the acute phase response was markedly more costly than the subsequent adaptive response. The weight of the cells and proteins of the systemic immune system prior to challenge was 0.14% of body weight. Following E. coli injection, the additional weight of the immune components and the hypertrophy of the liver resulted in a 3.6-fold increase in weight which is equivalent to 18.5% of a large egg.

[Protective effect of miliacin during experimental salmonellosis infection].

AIM: Evaluation of influence of triterpenoid miliacin on the development of experimental salmonellosis infection. MATERIALS AND METHODS: Studies were carried out in 330 male mice (CBAxC57Bl6)F1. Miliacin was administered 3 times intraperitoneally with the interval of 3 days between administrations at a single dose of 2 mg/kg. The animals were infected intraperitoneally by hospital origin Salmonella enteritidis strain (2x10(6) bacteria per mice). 4 groups of mice were used: I - intact; II - infected; III - infected after administering solvent for miliacin 3 times (tween 21 at final concentration of 1.6x 10(-7) mol/kg); IV - infected after administration ofmiliacin. RESULTS: Miliacin reduced the mortality of mice compared with groups II and III. Microbial contamination of mice spleen in group IV was significantly lower compared with group II at all the periods of the study, and liver - at days 10 and 15. Triterpenoid weakened cell depletion of bone marrow, thymus and limited hyperplasia of spleen compared with animals of groups II and III. Its protective effect did not correlate with increase of antibody titers. CONCLUSION: Miliacin weakens the severity of salmonellosis infection course.

Neuroendocrine-immunology of experimental Chagas' disease.

The cytokine-mediated stimulation of the hypothalamus-pituitary-adrenal (HPA) axis is relevant for immunoregulation and survival during bacterial endotoxemia and certain viral infections. However, only limited information is available regarding the effect of endogenous glucocorticoids on parasitic diseases. Here, we discuss evidence that the increased levels of corticosterone that occur following Trypanosoma cruzi infection in mice is an endocrine response that protects the host by impeding an excessive production of pro-inflammatory cytokines. Comparative studies between susceptible C57Bl/6J and resistant Balb/c mice indicate that the predisposition to the disease depends on the appropriate timing and magnitude of the activation of the HPA axis. However, this endocrine response also results in thymus atrophy and depletion of CD4(+)CD8(+) by apoptosis. On the other hand, using tumor necrosis factor (TNF)-receptor knockout mice, we found that TNF-alpha plays a complex role during this disease; it is involved in the mediation of cardiac tissue damage but it also contributes to prolonged survival. Taken together, this evidence indicates that a subtle balance between endocrine responses and cytokine production is necessary for an efficient defense against T. cruzi infection.

Tuberculosis of thymus--a case report.

Tuberculosis rarely figures in the list of thymic masses. We hereby report a case of thymic tuberculosis successfully managed with surgical excision and antituberculouschemotherapy.

The thymus as a target for mycobacterial infections.

Mycobacterial infections are among the major health threats worldwide. Ability to fight these infections depends on the host's immune response, particularly on macrophages and T lymphocytes produced by the thymus. Using the mouse as a model, and two different routes of infection (aerogenic or intravenous), we show that the thymus is consistently colonized by Mycobacterium tuberculosis, Mycobacterium avium or Mycobacterium bovis BCG. When compared to organs such as the liver and spleen, the bacterial load reaches a plateau at later time-points after infection. Moreover, in contrast with organs such as the spleen and the lung no granuloma were found in the thymus of mice infected with M. tuberculosis or M. avium. Since T cell differentiation depends, to a large extent, on the antigens encountered within the thymus, infection of this organ might alter the host's immune response to infection. Therefore, from now on, the thymus should be considered in studies addressing the immune response to mycobacterial infection.

Impaired phagocytosis in caveolin-1 deficient macrophages.

Caveolae are plasma membrane invaginations that function as important regulators of numerous cellular processes, including signal transduction, cholesterol trafficking, and endocytosis. Caveolin-1 (Cav-1) constitutes the main structural protein of caveolae membranes. Here, we report an in vivo increase in the number of apoptotic cells in the thymus and spleen of Cav-1 deficient mice, following whole-body gamma-irradiation. We demonstrate that this increase in apoptotic cells is not due to increased apoptosis in lymphocytes per se, which normally do not express Cav-1, but rather to the decreased phagocytic clearance of apoptotic cells by macrophages, which do express Cav-1. Utilizing in vitro phagocytosis assays of both apoptotic thymocytes and Escherichia coli K-12 BioParticles, we demonstrate that the loss of Cav-1 decreases the phagocytic ability of thioglycollate-elicited peritoneal macrophages. We suggest that impaired macrophage phagocytosis in Cav-1 knockout mice could have implications for altered innate immunity against pathogens, the regulation of inflammatory responses, and the development of autoimmune disease.

Novel binding epitope for Helicobacter pylori found in neolacto carbohydrate chains: structure and cross-binding properties.

Helicobacter pylori is a bacterium that colonizes the stomach of a majority of the global human population causing common gastric diseases like ulcers and cancer. It has an unusually complex pattern of binding to various host glycoconjugates including interaction with sialylated, sulfated, and fucosylated sequences. The present study describes an additional binding epitope comprising the neolacto internal sequence of GlcNAcbeta3-Galbeta4GlcNAcbeta. The binding was detected on TLC plates as an interaction with a seven-sugar ganglioside of rabbit thymus. The glycolipid was purified and characterized as Neu5Gcalpha3Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3-Galbeta4Glcbeta1Cer with less than 10% of the fraction carrying a repeated lacto (type-1) core chain, Galbeta3Glc-NAcbeta3Galbeta3GlcNAcbeta. After stepwise chemical and enzymatic degradation and structural analysis of products the strongest binder was found to be the pentaglycosylceramide GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1-Cer, whereas the hexa- and tetraglycosylceramides were less active, and the trihexosylceramide was inactive. Further studies revealed that the terminal GlcNAcbeta of the pentaglycosylceramide may be exchanged for either GalNAcbeta3, GalNAcalpha3, or Galalpha3 without loss of the activity. Calculated minimum energy conformers of these four isoreceptors show a substantial topographical similarity suggesting that this binding is a result of a molecular mimicry. Although the glycoconjugate composition of human gastric epithelial cells is not known in detail it is proposed that repeating N-acetyllactosamine units of glycoconjugates may serve as bacterial attachment sites in the stomach.

Response of different organs of immune system of mice upon administration bacterial CpG DNA.

UNLABELLED: CpG DNA are potent immunostimulator and currently being tested as adjuvant in immunotherapy of various diseases. THE AIM of this study was to investigate the effects of a single dose of bacterial CpG DNA challenge on response of murine immune system organs and on a zeta-potential of different lymphoid organ cells and peritoneal macrophages in normal and tumor-bearing mice. METHODS: Indexes and cellularity of immune organs of mice were evaluated. Z-potential was measured by cellular electrophoresis. RESULTS: Subcutaneous administration of CpG DNA induced local transitory hyperplasia of lymph nodes, moderate increase of splenic index and total spleen cellularity, whereas intraperitoneal injection of CpG DNA caused full-blown spleen enlargement and increase of splenocyte content, and also mice showed transitory aseptic peritonitis. Response of thymus on challenge of CpG DNA was bi-phase: initial phase - response on antigen as stimulus, and late proliferative phase. It was noted that tumor growth does not affect zeta-potential in peritoneal macrophages and mononuclear lymphocytes, but causes increase of zeta-potential on thymocytes and decreases it in lymphocytes from lymph nodes. Furthermore, single administration of CpG DNA normalizes of thymocytes and lymph nodes lymphocytes zeta-potential and increases it in peritoneal macrophages and mononuclear lymphocytes. CONCLUSION: The findings demonstrate a close correlation between the hyperplasia of lymphoid follicles induced by challenge of CpG DNA and increase of their cellularity. Observed Z-potential alterations of immune system cells after CpG DNA immunization evidence on more significant polyanion accumulation on the surface of splenic macrophages and mononuclear cells.

Thymus tuberculosis poorly responding to anti-mycobacterial therapy in a young girl with primary infection.

Tuberculous infection of the thymus is a rare condition, previously described only in young adults. A case of a young girl with primary pulmonary tuberculosis, hilar and mediastinal lymph node enlargement and a partially necrotic mass in antero-superior mediastinum is described. Treatment with three anti-mycobacterial drugs was started, effective in markedly reducing all the intrathoracic abnormalities with the exception of the antero-superior mediastinal mass. Since the radiographic and ultrasonographic appearance of the thymus tuberculous infection may be indistinguishable from other serious conditions, including lymphoma and thymoma, a diagnostic procedure was performed. Evaluation of the resected specimen showed foci of caseation and multiple granulomas with extensive central necrosis within the thymic tissue.

Thymus invasion and atrophy induced by Paracoccidioides brasiliensis in BALB/c mice.

Literature has shown that immunosuppression observed in systemic mycosis can be related to damage in primary lymphoid organs. We have studied the immunopathological alterations induced experimentally by Paracoccidioides brasiliensis in these organs. In this work, thymic alterations induced in BALB/c mice during acute and chronic stages of infection are described. It was observed that P. brasiliensis is able to invade the thymic microenvironment, inducing severe atrophy characterized by degeneration of the cortical area, organ weight decrease, loss of corticomedullary delimitation and increase in histiocyte number. Occurrence of polymorphonuclear infiltration in the subcapsular area was also observed. Our results demonstrate that P. brasiliensis induces profound thymic atrophy and raises the question of whether this could be a fungal strategy to achieve successful establishment in the host over the long term.

Programmed cell death in thymus during experimental paracoccidioidomycosis.

Many works have shown that immunosuppressive effects induced by systemic mycosis can be related to primary lymphoid organ damage. Previous studies in our laboratory showed that Paracoccidioides brasiliensis was able to invade the thymus, inducing a severe atrophy with significant reduction of cortical area along with a loss of cortico-medullary boundary. The objective of the present study was to investigate whether thymic atrophy is caused by programmed cell death (PCD) and to examine the ultrastructural characteristics of the thymus in experimentally infected BALB/c mice. The results revealed an eightfold increase in the apoptotic index occurring by day 5 post infection, i.e., during early stages of the infection, shown by immunohistochemistry. In addition, typical cell alterations of autophagic PCD were observed by transmission electron microscopy. Taken together, these results reinforce the idea that thymic alterations may be involved in the immunosuppressive phenomenon frequently associated with paracoccidioidomycotic infection.

New Ehrlichia species closely related to Ehrlichia chaffeensis isolated from Ixodes ovatus ticks in Japan.

Seven Ehrlichia strains (six HF strains and one Anan strain) that were obtained from laboratory mice by intraperitoneally inoculating homogenates of adult Ixodes ovatus collected in Japan were characterized. 16S rRNA sequences of all six HF strains were identical, and the sequences were 99.7, 98.2, and 97.7% identical to those of Anan strain, Ehrlichia chaffeensis (human monocytic ehrlichiosis agent), and E. muris, respectively. Partial GroEL amino acid sequencing also revealed that the six HF strains had identical sequences, which were 99.0, 98.5, and 97.3% identical to those of E. chaffeensis, the Anan strain, and E. canis, respectively. All HF strains were lethal to mice at higher dosages and intraperitoneal inoculation, whereas the Anan or E. muris strain induced only mild clinical signs. Light and electron microscopy of moribund mice inoculated with one of the HF strains revealed severe liver necrosis and the presence of numerous ehrlichial inclusions (morulae) in various organs. The study revealed that members of E. canis genogroup are naturally present in Ixodes ticks. HF strains that can cause severe illness in immunocompetent laboratory mice would be valuable in studying the pathogenesis and the roles of both cellular and humoral immune responses in ehrlichiosis caused by E. canis genogroup.