MICROBIOME AND UVEITIDES. A REVIEW.

Microorganisms inhabiting all surfaces of mucous membranes and skin and forming a complex ecosystem with the host is called microbiota. The term microbiome is used for the aggregate genome of microbiota. The microbiota plays important role in the mechanisms of number of physiological and pathological processes, especially of the hosts immune system. The origin and course of autoimmune diseases not only of the digestive tract, but also of the distant organs, including the eye, are significantly influenced by intestinal microbiota. The role of microbiota and its changes (dysbiosis) in the etiopathogenesis of uveitis has so far been studied mainly in experimental models. Reduction of severity of non-infectious intraocular inflammation in germ-free mice or in conventional mice treated with broad-spectrum antibiotics was observed in both the induced experimental autoimmune uveitis model (EAU) and the spontaneous R161H model. Studies have confirmed that autoreactive T cell activation occurs in the intestinal wall in the absence of retinal antigen. Recent experiments focused on the effect of probiotic administration on the composition of intestinal microbiota and on the course of autoimmune uveitis. Our study group demonstrated significant prophylactic effect of the administration of the probiotic Escherichia coli Nissle 1917 on the intensity of inflammation in EAU. To date, only a few studies have been published investigating intestinal dysbiosis in patients with uveitis (e.g., in Behcets disease or Vogt-Koyanagi-Harada syndrome). The results of preclinical studies will be presumably used in clinical practice, mainly in the sense of prophylaxis and therapy, such as change in the lifestyle, diet and especially the therapeutic use of probiotics or the transfer of faecal microbiota.

Oral administration of Parabacteroides distasonis antigens attenuates experimental murine colitis through modulation of immunity and microbiota composition.

Commensal bacteria have been shown to modulate the host mucosal immune system. Here, we report that oral treatment of BALB/c mice with components from the commensal, Parabacteroides distasonis, significantly reduces the severity of intestinal inflammation in murine models of acute and chronic colitis induced by dextran sulphate sodium (DSS). The membranous fraction of P. distasonis (mPd) prevented DSS-induced increases in several proinflammatory cytokines, increased mPd-specific serum antibodies and stabilized the intestinal microbial ecology. The anti-colitic effect of oral mPd was not observed in severe combined immunodeficient mice and probably involved induction of specific antibody responses and stabilization of the intestinal microbiota. Our results suggest that specific bacterial components derived from the commensal bacterium, P. distasonis, may be useful in the development of new therapeutic strategies for chronic inflammatory disorders such as inflammatory bowel disease.

Protein levels of CC chemokine ligand (CCL)15, CCL16 and macrophage stimulating protein in patients with sarcoidosis.

The objective of this study was to assess protein levels for candidate cytokines, chemokines, growth factors, matrix metalloproteinases and their inhibitors in bronchoalveolar lavage fluid (BALF) in patients with polar forms of pulmonary sarcoidosis, i.e. Löfgren's syndrome (LS) and more advanced chest X-ray (CXR) stage III disease. Twenty-four inflammatory molecules were analysed in unconcentrated BALF samples from 10 sarcoidosis patients with CXR stage III and 10 patients with LS by semiquantitative protein array. Four novel molecules [CC chemokine ligand (CCL)15, CCL16, macrophage migration inhibitory factor (MIF) and macrophage stimulating protein (MSP)], detected for the first time in association with sarcoidosis, were then quantified by enzyme-linked immunosorbent assay in a second cohort of 68 sarcoidosis patients and 17 control subjects. The protein levels of CCL15, CCL16, CCL24, CXCL8, CXCL9, CXCL10, interleukin-16, MIF, MSP and matrix metallopeptidase 1 were increased in CXR stage III patients when compared with patients with LS. CCL15 and MSP up-regulation in CXR stage III patients in comparison with LS patients and controls was confirmed by enzyme-linked immunosorbent assay. Moreover, MSP was associated with treatment requirement (P = 0.001) and CCL15 was elevated in patients with disease progression at 2-year follow-up (P = 0.016). CCL16 levels were increased in sarcoidosis versus controls (P < 0.05), but no difference was observed between patient subgroups. MIF up-regulation was not confirmed in a larger patient group. In conclusion, chemokines CCL15, CCL16 and MSP were found elevated for the first time in BALF from sarcoidosis patients; our results showed that CCL15 and MSP may affect disease course.

Multiplex analysis of cytokines involved in tumour growth and spontaneous regression in a rat sarcoma model.

The aim of our study was to examine in vivo and in vitro cytokines produced by Lewis ratderived R5-28 sarcoma cells. These cells produce rapidly growing tumours in approximately two weeks after subcutaneous inoculation. However, spontaneous tumour regression was noted in about 40% of animals. For an explanation of this phenomenon, we evaluated the profile of 19 cytokines during tumour growth and spontaneous regression by the use of "antibody array". To detect cytokines directly originated by the sarcoma, the R5-28 cells were cultivated in vitro and then both the supernatants and the cell lysates were analysed. Our experiments showed three cytokines (MCP-1, TIMP-1 and VEGF) to be produced by R5-28 cells in vitro. Moreover, in vivo, another three cytokines (TNF-alpha, beta-NGF and LIX) were detected both in blood sera and tumour lysates, probably produced by immune and stromal cells during tumour growth. Changes in their expression after spontaneous regression are discussed.

Perinatal period cytokines related to increased risk of future allergy development.

Testing of cytokine levels in colostrum, cord blood and amniotic fluid of healthy and allergic mothers and their newborns (using protein microarrays and quantitative analysis by ELISA) revealed differences in the levels of IL-5, IL-10, TGF-beta, TNF-alpha, EGF and eotaxin between healthy and allergic groups. Significantly higher concentration of IL-5 and IL-10 in the colostrum of allergic mothers and cord blood of their children and also tendency to a higher level of IL-4 found at allergic mothers and their children (but without statistical significance) indicate a bias to T(H)2 response in this group. The higher level of TGF-beta in the colostrum of healthy mothers should be involved in beneficial immunological tuning of their children including enhanced IgA formation and better intestine maturation. In amniotic fluid, concentration of TGF-beta was higher in children of allergic mothers. A significantly higher level of EGF was proved in the colostrum of healthy mothers and in cord blood of their children in comparison with allergic group. EGF deficiency in the allergic group could impair or delay intestine maturation and support thus allergy development.

Oral administration of probiotic bacteria (E. coli Nissle, E. coli O83, Lactobacillus casei) influences the severity of dextran sodium sulfate-induced colitis in BALB/c mice.

Our study examined whether repeated preventive oral administration of live probiotic bacterial strains Escherichia coli O83:K24:H31 (Ec O83), Escherichia coli Nissle 1917 O6:K5:H1 (Ec Nis) and Lactobacillus casei DN 114001 (Lc) can protect mice against dextran sodium sulfate (DSS)-induced colitis. A significant decrease in average symptom score was observed in Ec O83-, Ec Nis- and Lc-pretreated group (p < 0.05). Significant differences in body mass loss between Lc pretreated mice with DSS-induced colitis were found when compared with nontreated mice (p < 0.05). PBS pretreated mice had a significantly shorter colon than Ec O83-, Ec Nis- and Lc-pretreated mice (p < 0.05). Administration of Lc significantly decreased the severity of DSS induced histological marks of inflammation (p < 0.05). A significant difference (p < 0.05) was also found in specific IgA level against given probiotic in enteral fluid between colitic mice and healthy mice pretreated with Ec 083 and Ec Nis.

Intestinal inflammation modulates expression of 11beta-hydroxysteroid dehydrogenase in murine gut.

The effect of glucocorticoids is controlled at the pre-receptor level by the activity of 11beta-hydroxysteroid dehydrogenase (11HSD). The isoform 11HSD1 is an NADP+ -dependent oxidoreductase, usually reductase, that amplifies the action of glucocorticoids due to reduction of the biologically inactive 11-oxo derivatives cortisone and 11-dehydrocorticosterone to cortisol and corticosterone. The NAD+ -dependent isoform (11HSD2) is an oxidase that restrains the effect of hormones due to 11beta-oxidation of cortisol and corticosterone to their 11-oxo derivatives. Although the immunosuppressive and anti-inflammatory effects of glucocorticoids are well known, the relationship between inflammation and local metabolism of glucocorticoids is not well understood. In this study, we demonstrated that colitis induced by dextran sulfate sodium modulates colonic 11HSD1. Experimentally induced intestinal inflammation stimulated colonic NADP+ -dependent but not NAD+ -dependent 11HSD activity. Colonic 11HSD1 mRNA was increased, whereas 11HSD2 mRNA was not changed. Additional parallel studies revealed a similar pattern of 11HSD1 mRNA induction in mesenteric lymph nodes and intestinal intraepithelial lymphocytes, but not in spleen and peritoneal macrophages. These data suggest that inflammation modulates local metabolism of glucocorticoid and support the notion that pre-receptor regulation of endogenous corticosteroids might play a role in inflammatory processes.

Interaction of mucosal microbiota with the innate immune system.

Organisms live in continuos interaction with their environment; this interaction is of vital importance but at the same time can be life threatening. The largest and most important interface between the organism and its environment is represented by surfaces covered with epithelial cells. Of these surfaces, mucosae comprise in humans approximately 300 m2, and the skin covers approximately 1.8 m2 surface of the human body. Mucosal tissues contain two effector arms of the immune system, innate and adaptive, which operate in synergy. Interaction with commensal bacteria, which outnumber the nucleated cells of our body, occurs physiologically on epithelial surfaces; this interaction could pose the risk of inflammation. The mucosal immune system has developed a complex network of regulatory signalling cascades that is a prerequisite for proper activation but also for a timely inactivation of the pathway. As demonstrated in gnotobiotic animal models of human diseases, impaired regulation of mucosal responses to commensal bacteria plays an important role in the development of several inflammatory and autoimmune diseases.