The "psychomicrobiotic": Targeting microbiota in major psychiatric disorders: A systematic review.

The gut microbiota is increasingly considered as a symbiotic partner in the maintenance of good health. Metagenomic approaches could help to discover how the complex gut microbial ecosystem participates in the control of the host's brain development and function, and could be relevant for future therapeutic developments, such as probiotics, prebiotics and nutritional approaches for psychiatric disorders. Previous reviews focused on the effects of microbiota on the central nervous system in in vitro and animal studies. The aim of the present review is to synthetize the current data on the association between microbiota dysbiosis and onset and/or maintenance of major psychiatric disorders, and to explore potential therapeutic opportunities targeting microbiota dysbiosis in psychiatric patients.

[Austrian nutrition and lifestyle recommendations for gout and hyperuricemia]. / Österreichische Ernährungs- und Lebensstilempfehlungen bei Gicht und Hyperurikämie.

BACKGROUND: Gout is the most common inflammatory arthropathy in the Western world. This is mainly due to the high socioeconomic status, sufficient even superfluous nutrition, overweight and alcohol consumption. Despite adequate medication, information and advice on nutrition and lifestyle are one of the cornerstones in the management of these patients. OBJECTIVE: The aim was to provide recommendations on nutrition and lifestyle in cases of gout and hyperuricemia by a group of rheumatologists, based on a review of the most recent literature. MATERIALS AND METHODS: The study group for osteoarthritis and crystal arthropathies of the Austrian Society for Rheumatology and Rehabilitation (ÖGR) carried out a literature search on this topic. The selected papers were listed according to the level of evidence. RESULTS: Based on this literature search nine recommendations were generated and modified via a Delphi approach: four red "don'ts" concerning nutrition and beverages to be avoided, three green "do's" concerning favorable food as well as two blue general lifestyle recommendations. The format of the recommendations is a two-page leaflet with the list of recommendations, level of evidence, strength of recommendation and literature citations on the front page and a colored icon presentation of food and beverages in a circle, matching the colors of the written recommendations, on the reverse. CONCLUSION: For the first time in Austria, nine recommendations on nutrition, beverages and lifestyle for patients with gout and hyperuricemia were defined for everyday practice, as education material for patients and updated information for physicians.

Autoantibody profiling in patients with very early rheumatoid arthritis: a follow-up study.

OBJECTIVE: To investigate time courses of autoantibody profiles in patients with early arthritis. PATIENTS AND METHODS: A total of 200 patients with very early arthritis (<3 months duration), among them 102 patients with a final diagnosis of rheumatoid arthritis (RA) and 98 with other rheumatic diseases, were followed up for several years. First follow-up testing was performed in all patients (mean 5 months from baseline), and 82 patients with RA and 35 patients without RA were available for last follow-up testing (mean 32 months from baseline). IgM-rheumatoid factor (RF) was measured by nephelometry, IgA-RF, IgG-RF and anti-cyclic citrullinated peptide antibodies (ACPA) by ELISA, and anti-RA33 antibodies were determined by immunoblotting. RESULTS: At baseline, IgA-RF was detectable in 29% and IgG-RF in 14% of patients with RA while IgM-RF>50 IU/ml (RF50) was positive in 45% of the patients; specificities were 97%, 99% and 96%, respectively. However, the vast majority of patients positive for IgA-RF or IgG-RF were also positive for RF50 or ACPA. During follow-up, the prevalence of ACPA slightly increased while prevalence of all RF subtypes and anti-RA33 decreased. Remarkably, the number of patients positive for RF50 and/or ACPA remained constant, and these patients had a highly increased risk for developing erosive disease in contrast to patients solely positive for anti-RA33. CONCLUSIONS: Testing for RF subtypes did not provide additional diagnostic information. Patients positive for RF50 and/or ACPA had an unfavourable prognosis, irrespectively of changes in the antibody profile during follow-up, whereas anti-RA33 positivity was inversely associated with erosiveness at baseline and at later time points.

RORγt, a multitask nuclear receptor at mucosal surfaces.

RORγt is a nuclear hormone receptor that has followed an exponential success carrier. Its modest origins as an orphan receptor cloned from human pancreas blossomed within 15 years into a critical regulator of anti-microbial immunity and a major target in the fight against inflammatory pathologies. Here, I review its role as a transcription factor required for the generation of type 3 lymphoid cells, which induce the development of lymphoid tissues, provide resistance of epithelial stem cells to injury, maintain homeostasis with the symbiotic microbiota, orchestrate defense against extracellular microbes, and regulate allergic responses. RORγt is also an intriguing molecule that is regulated by the circadian rhythm and includes cholesterol metabolites as ligands. RORγt therefore links anti-microbial immunity with circadian rhythms and steroids, the logic of which remains to be understood.

Extracellular processing and presentation of a 69-mer synthetic polypetide to MHC class I-restricted T cells.

The classical pathway for MHC class-I-restricted Ag presentation processes cytosolic Ag synthesized in or delivered into the cytosol for binding to MHC class I molecules in the ER. Alternatively, Ag may be processed and bind class I molecules in endocytic compartments or at the cell surface after regurgitation of processed peptides. We show that a 69-mer synthetic polypeptide that carries the optimal 9-mer Kd-restricted epitope from the Plasmodium berghei circumsporozoite protein, PbCS 245-253, is presented to CD8+ T cells after a short incubation (1-2 h) with target cells. The presentation kinetics correlate with the length of the peptides when shorter peptide analogues are used. This presentation is independent of the transporters associated with antigen processing and presentation (TAP), does not require newly synthesized proteins and does not proceed via regurgitation of intracellularly processed peptides. In contrast, it is substantially decreased in the absence of beta2 microglobulin or serum. Taken together, these data suggest that serum components, such as proteases and beta2 microglobulin, allow the processing and loading of exogenous polypeptides onto empty cell surface class I molecules for presentation to CTL.

Ca2+ uptake and IP3-induced Ca2+ release in permeabilized human lymphocytes.

The 45Ca2+ uptake and 45Ca2+ release in saponin-permeabilized human lymphocytes were studied. An ATP-dependent Ca2+ uptake into a nonmitochondrial, intracellular Ca2+ store is observed which is approx. 2 orders of magnitude greater than the ATP-independent Ca2+ uptake. The Ca2+ uptake is inhibited by vanadate, but it is insensitive to oligomycin and ruthenium red. IP3 induces dose-dependent 45Ca2+ release. For half-maximum Ca2+ release 0.25-0.5 microM IP3 is required. The results of our studies suggest that 45Ca2+ is predominantly stored within the endoplasmic reticulum of the lymphocytes.

CD8+ T-cell protective immunity induced by immunization with Plasmodium berghei CS protein-derived synthetic peptides: evidence that localization of peptide-specific CTLs is crucial for protection against malaria.

Immunization of BALB/c mice (H-2d) with a mixture of major histocompatibility complex (MHC) class I- and MHC class II-restricted synthetic peptides emulsified in incomplete Freund's adjuvant (IFA) induced a high level of specific cytotoxic T lymphocyte (CTL) activity. Peptides 249-260 or 252-260, derived from the circumsporozoite protein of Plasmodium berghei and representing a H-2Kd-restricted CTL epitope, were injected twice subcutaneously or intraperitoneally in BALB/c mice in combination with the tetanus toxin-derived universal T-helper peptide P30 in IFA. No protection was observed after exposure of immunized mice to infected mosquitoes. In contrast, when peptide 252-260-specific CTLs were expanded in vitro and adoptively transferred into naive recipient, mice were partially protected (64%) against a subsequent sporozoite challenge. Furthermore, direct transfer of lymph nodes or spleen cells from mice immunized with the peptide PbCS 252-260 also conferred protection to recipient mice. This protection was long-lasting and similar to that obtained with irradiated sporozoites.

Low serum hyaluronan in psoriatic arthritis patients in comparison to rheumatoid arthritis patients.

OBJECTIVE: Serum hyaluronan (HA) was determined in 37 patients suffering from psoriatic arthritis (PSA), 39 patients with rheumatoid arthritis (RA), 31 with osteoarthritic joint disease (OA) and 26 healthy controls (C) in order to examine earlier reports that HA levels are increased in the serum of RA and to assess whether this finding is also relevant for PSA, another inflammatory joint disease, since HA in serum is considered a sign of inflammation in general. METHOD: HA in the serum samples was measured with an enzyme linked microplate assay. RESULTS: Sera from PSA, RA and OA patients showed a significantly higher HA concentration than those of healthy controls (56.0 +/- 16.0 micrograms/l). The serum HA concentration in PSA patients amounted to 107.8 +/- 57.2 micrograms/l, which was not significantly different from OA patients (104.9 +/- 16 micrograms/l). A significant difference, however, could be observed between the HA concentrations of the PSA subgroups: the mean HA level of patients suffering from symmetrical polyarthritis was 134 +/- 79.6 micrograms/l, which turned out to be significantly higher than in patients suffering from symmetrical oligoarthritis (89.9 +/- 42.8 micrograms/l; P < 0.04), but was insignificantly increased in comparison to patients with ankylosing spondylitis as the predominant feature (109 +/- 27.8 micrograms/l; P = 0.49). The mean HA concentration for RA sera was 197.1 +/- 122.9 micrograms/l, which was statistically significantly increased compared to PSA (P < 0.001) and OA (P < 0.001) sera. The sera of seropositive RA patients showed significantly higher HA levels than PSA patients with symmetrical polyarthritis (P < 0.04). CONCLUSION: The data obtained support recent studies which have shown HA levels to be higher in RA patients than in OA patients. Seronegative and seropositive RA patients showed the same HA concentrations, while patients suffering from "seronegative" PSA were found to have lower HA concentrations. Therefore, HA serum levels may reflect cartilage degradation in general or the degree of articular inflammatory processes, indicating different pathogenetic pathways.

The Austrian Early Arthritis Registry.

The Austrian Early Arthritis Registry (Austrian Early Arthritis Action, EAA) enrols and follows patients with inflammatory arthritis of very short (< 12 weeks) duration. Currently, data on 375 patients (almost 2000 individual follow-up examinations) have been entered into the EA database. Evaluations of data from 182 patients with a follow-up of at least one year are available. 65% of these patients have RA, as diagnosed using the ACR classification criteria in a cumulative fashion. Approximately 15% of these patients still have no established diagnosis and are being carried forward and observed as cases of "undifferentiated arthritis". In RA patients, the mean DAS 28 decreased significantly from an initial mean score of 5.5 (high disease activity) into the range of low disease activity. At the end of one year a DAS 28 of < 3.2 was observed in 52% of the RA patients. Radiological progression in these RA patients, who also received treatment very early, appears to be less severe than in other cohorts, although direct comparisons are impossible due to different methods of patient selection. In addition, the serological data from our cohort in cooperation with other study groups will allow development and validation of possible prediction algorithms for early arthritis patients which could improve the diagnostic and therapeutic approach to this patient group.

Early arthritis therapy: rationale and current approach.

Rheumatoid arthritis (RA) is a disease that seriously affects patients' quality of life and may lead to disability or even premature death, despite the availability of effective treatments. Evidence suggests that delay of treatment may be the main contributing factor for poor outcome. Delay is caused primarily by the erroneous belief that the course of RA may be controlled in many cases by mild measures such as nonsteroidal antiinflammatory drugs, physiotherapy, and rest. While this may be true in a certain percentage of patients, many patients with RA progress to severe disability. To prevent progression of disease, early treatment of RA, particularly in patients at high risk, seems mandatory. Therefore, early arthritis clinics (EAC) have been established in a number of countries. We discuss the rationale for early intervention and our experiences in Austrian EAC.

Regulatory T cells promote a protective Th17-associated immune response to intestinal bacterial infection with C. rodentium.

Intestinal infection with the mouse pathogen Citrobacter rodentium induces a strong local Th17 response in the colon. Although this inflammatory immune response helps to clear the pathogen, it also induces inflammation-associated pathology in the gut and thus, has to be tightly controlled. In this project, we therefore studied the impact of Foxp3(+) regulatory T cells (Treg) on the infectious and inflammatory processes elicited by the bacterial pathogen C. rodentium. Surprisingly, we found that depletion of Treg by diphtheria toxin in the Foxp3(DTR) (DEREG) mouse model resulted in impaired bacterial clearance in the colon, exacerbated body weight loss, and increased systemic dissemination of bacteria. Consistent with the enhanced susceptibility to infection, we found that the colonic Th17-associated T-cell response was impaired in Treg-depleted mice, suggesting that the presence of Treg is crucial for the establishment of a functional Th17 response after the infection in the gut. As a consequence of the impaired Th17 response, we also observed less inflammation-associated pathology in the colons of Treg-depleted mice. Interestingly, anti-interleukin (IL)-2 treatment of infected Treg-depleted mice restored Th17 induction, indicating that Treg support the induction of a protective Th17 response during intestinal bacterial infection by consumption of local IL-2.

Development and function of intestinal innate lymphoid cells.

Innate lymphoid cells (ILCs) are generated from common lymphoid precursors, like lymphocytes, but do not express an antigen receptor. ILCs include Natural Killer (NK) cells, first described 38 years ago, as well as the more recently discovered lymphoid tissue inducer (LTi) cells, NK(22) cells and ILC2s. ILCs reflect many functions of CD4(+) T helper cells by expressing IFNγ, IL-17, IL-22 or IL-13. However, in contrast to T cells, they are not selected on the basis of antigen specificity, and expand and act shortly after stimulation. Therefore, ILCs play fundamental roles early in responses to infection and injury, in the maintenance of homeostasis, and possibly in the regulation of adaptive immunity. Here, we review the recent data on the development and role of RORγt(+) ILCs and ILC2s in intestinal homeostasis and defense.

A new vision of immunity: homeostasis of the superorganism.

The immune system is commonly perceived as an army of organs, tissues, cells, and molecules that protect from disease by eliminating pathogens. However, as in human society, a clear definition of good and evil might be sometimes difficult to achieve. Not only do we live in contact with a multitude of microbes, but we also live with billions of symbionts that span all the shades from mutualists to potential killers. Together, we compose a superorganism that is capable of optimal living. In that context, the immune system is not a killer, but rather a force that shapes homeostasis within the superorganism.

The development of intestinal lymphoid tissues at the interface of self and microbiota.

Intestinal lymphoid tissues face the challenging task of inducing adaptive immunity to pathogens, yet maintaining homeostasis with the enormous commensal microbiota. To that aim, the ancient partnership between self and flora has resulted in the generation of a unique set of lymphoid tissues capable of constant large-scale reformatting. A first set of lymphoid tissues, the mesenteric lymph nodes and Peyer's patches, are programmed to develop in the sterile environment of the fetus, whereas a second set of lymphoid tissues, the tertiary lymphoid tissues, are induced to form by the microbiota and inflammation. The diversity of intestinal lymphoid tissues confers the flexibility required to adapt the number of immune inductive sites to the size of the flora and the extent of the pathogenic threat. The result is a functional superorganism combining self and microbes for the best possible symbiosis.

Autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis.

BACKGROUND: Early treatment prevents progression of joint damage in rheumatoid arthritis (RA), but diagnosis in early disease is impeded by lack of appropriate diagnostic criteria. OBJECTIVE: To study the value of rheumatoid factor (RF), anti-cyclic citrullinated peptide autoantibodies (anti-CCP), and anti-RA33 autoantibodies for diagnosis of RA and prediction of outcome in patients with very early arthritis. METHODS: The prospective follow up inception cohort included 200 patients with very early (<3 months) inflammatory joint disease. Autoantibodies were measured at baseline and analysed in a tree based model which aimed at determining the added diagnostic value of testing for anti-CCP and anti-RA33 as compared with RF alone. RESULTS: RA was diagnosed in 102 patients, while 98 developed other inflammatory arthropathies. Receiver operator curve analysis showed an optimum cut off level for RF at 50 U/ml, above which anti-CCP and anti-RA33 had no additional diagnostic value. Remarkably, RF >or=50 U/ml and anti-CCP showed similar sensitivity and high specificity for RA, but overlapped considerably. Anti-RA33 was less specific and did not correlate with RF or anti-CCP. Among patients with RA, 72% showed at least one of these three autoantibodies, compared with 15% of non-RA patients. RF >or=50 U/ml and anti-CCP were predictors of erosive disease, whereas anti-RA33 was associated with mild disease. CONCLUSIONS: Stepwise autoantibody testing in early inflammatory joint disease, starting with RF, followed by anti-CCP (in patients with RF <50 U/ml), and finally anti-RA33, should be used as a sensitive and effective strategy for distinguishing patients with RA at high risk for poor outcome.

The functional half-life of H-2Kd-restricted T cell epitopes on living cells.

The functional half-life (t1/2) of different complexes formed by major histocompatibility complex (MHC) class I molecules and antigen on the surface of target cells was measured using specific cytotoxic T lymphocyte (CTL) clones in cytolysis, and interferon-gamma-production and Ca(2+)-mobilization assays. Functional t1/2 values of 5-10 h were obtained, which are in accordance with some previous estimations obtained from biochemical and immunochemical measurements. Moreover, these values were independent of the type of target cell, fixation of the target cells, or proteases able to degrade the peptides, suggesting that the unfolding of the peptide/MHC complexes at the cell surface alone determines the functional t1/2 of the CTL epitopes.

Selective induction of NK cell proliferation and cytotoxicity by activated NKT cells.

NK T cells produce cytokines when their semi-invariant TCR engages glycolipids associated with CD1d. The physiological consequences of NKT cell activation remain controversial, although they have been implicated in control of autoimmunity, parasites and tumors. We show here that specific activation of NKT cells in liver and spleen leads to a rapid induction of extensive NK cell proliferation and cytotoxicity. This NK cell activation is dependent, at least in part, on IFN-gamma production by NKT cells and IL-12 production by antigen-presenting cells. Remarkably, activation of NK cells by NKT cells is highly selective, since bystander T and B lymphocytes show transient expression of activation markers but almost no proliferation. Collectively our data suggest that CD1d-dependent NKT cells regulate innate immunity by sampling blood-borne glycolipid antigens and rapidly activating NK cells.

Rapid death and regeneration of NKT cells in anti-CD3epsilon- or IL-12-treated mice: a major role for bone marrow in NKT cell homeostasis.

Natural killer T (NKT) cells express a T cell receptor (TCR) and markers common to NK cells, including NK1.1. In vivo, NKT cells are triggered by anti-CD3epsilon MAb to rapidly produce large amounts of IL-4 and by IL-12 to reject tumors. We show here that anti-CD3epsilon MAb treatment rapidly depletes the liver (and partially the spleen) of NKT cells and that homeostasis is achieved 1 to 2 days later via NKT cell proliferation that occurs mainly in bone marrow. Similar results were obtained in mice treated with IL-12. Collectively, our data demonstrate that peripheral NKT cells are highly sensitive to activation-induced cell death and that bone marrow plays a major role in restoring NKT cell homeostasis.

A simple mathematical model for the functional peptide/MHC/TCR interactions.

T cell-specific activation requires ligation of TCRs with peptide-MHC complexes on the APC. On the basis of simple chemical and statistical laws, we have constructed a mathematical model to describe this trimolecular interaction between effector and target cells, and we demonstrate its predictive value in the case of in vitro peptide Ag titration. Moreover, this model can generate mechanistic explanations for cellular immunity phenomena like anergy, peripheral tolerance, cell-mediated suppression, TCR antagonism, and thymic selection events.