The effect of multimeric adiponectin isoforms and leptin on the function of rheumatoid fibroblast-like synoviocytes.

OBJECTIVES: To evaluate the effects of physiologically relevant concentrations of multimeric adiponectin isoforms and leptin on the function of fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). METHOD: FLS, isolated from the synovial tissue of 21 RA patients, were stimulated for 24 h with interleukin (IL)-1ß (1 ng/mL) and adiponectin isoforms [fraction enriched with high-molecular-weight (HMW) oligomers and middle-molecular-weight (MMW) hexamers or low-molecular-weight (LMW) trimers, 10 µg/mL each], or leptin (10 ng/mL), either separately or in a combination of IL-1ß and the respective adipokine. Moreover, cells were pre-treated for 24 h with adipokines, then stimulated for 8 h with IL-1ß. The concentrations of IL-6, IL-8, matrix metalloproteinase (MMP)-3, and dickkopf (DKK)-1, an inhibitor of osteoblastogenesis, in culture supernatants, as well as the concentrations of leptin, HMW, MMW, and LMW adiponectin in sera and synovial fluid (SF) samples, were measured by specific enzyme-linked immunosorbent assays (ELISAs). RESULTS: In comparison with sera, SF samples contained similar amounts of leptin, lower amounts of total adiponectin but a higher proportion of the LMW isoform. Separately added IL-1ß and HMW/MMW adiponectin, but not LMW adiponectin or leptin, up-regulated the release of IL-6, IL-8, and MMP-3 from FLS but no synergy was observed in co-stimulation experiments. However, pre-treatment of FLS with HMW/MMW or LMW significantly raised the IL-1ß-triggered secretion of MMP-3 and IL-6 or MMP-3, respectively. CONCLUSIONS: Adiponectin not only triggers pro-inflammatory and pro-destructive activities of rheumatoid FLS but also pre-disposes these cells to a stronger response to IL-1ß. Thus, it is likely that adiponectin is more important in the initiation phase than in the chronic phase of RA.

Altered expression of V1a receptors mRNA in the brain and kidney after myocardial infarction and chronic stress.

Vasopressin released during myocardial infarction and in response to stress regulates blood pressure through multiple actions exerted in the brain, cardiovascular system and kidney. The aim of the present study was to determine whether myocardial infarction influences expression of vasopressin V1a receptor (V1aR) mRNA and protein in the brain and kidney and whether stress has an impact on expression of these parameters during the post-infarct state. Male, adult Sprague Dawley rats were subjected to myocardial infarction or sham surgery. Seven days later some rats were exposed to mild stress for 4weeks whereas other stayed at rest. Tissue fragments were harvested from four groups of rats (control, infarct, stress, infarct+stress). Expression of V1aR mRNA (Real time PCR) was determined in the preoptic, diencephalic, mesencephalopontine and medullary regions of the brain and in the renal cortex and medulla. Protein V1aR expression (Western blotting) was determined in the brain mesencephalopontine region and in the kidney medulla. In the preoptic, diencephalic, and mesencephalopontine regions, V1aR mRNA expression was significantly lower in the infarcted rats than in the sham-operated unstressed controls. The infarcted rats manifested also lower expression of V1aR protein in the mesencephalopontine region than the other groups. The stressed group demonstrated significantly higher V1aR mRNA expression in the brain medulla and in the renal cortex and renal medulla than the control group. In all brain regions and in the kidney, V1aR mRNA expression was significantly higher in the stressed rats than in the infarcted rats. The stressed rats showed also higher expression of V1aR protein in the renal medulla than the other groups. It is concluded that myocardial infarction and chronic stress cause significant but differential changes in the regulation of V1a receptors expression in the brain and the kidney.

BAFF from bone marrow-derived mesenchymal stromal cells of rheumatoid arthritis patients improves their B-cell viability-supporting properties.

Mesenchymal stromal cells (MSCs) represent a unique cell type with anti-proliferative effects on activated T and B cells. Based on our observation of differences between rheumatoid arthritis and osteoarthritis bone marrow B cells we hypothesized that rheumatoid arthritis bone marrow MSCs may enhance B-cell survival. We aimed to compare the effect of rheumatoid arthritis and osteoarthritis bone marrow-derived MSCs (rheumatoid arthritis MSCs, osteoarthritis MSCs) on the survival of healthy donor purified B cells. Rheumatoid arthritis and osteoarthritis MSCs were isolated from patients undergoing hip replacement surgery, and cultured in vitro for 2-5 passages. Washed cells were co-cultured with CD20+ B cells for 30-90 hours. Cell survival was analysed using 7-amino-actinomycin D labelling by flow cytometry. Expression of mRNA and protein was determined by RT-PCR and flow cytomery. Co-culture with both rheumatoid arthritis MSCs and osteoarthritis MSCs significantly enhanced B-cell survival, the effect being more prominent in rheumatoid arthritis MSCs. Both types of MSCs displayed expression of B cell-activating factor mRNA and protein. Blocking B cell-activating factor signalling from MSCs by specific anti-B cell-activating factor and anti-B cell-activating factor receptor antibodies weakly reversed the effect of MSCs on B-cell survival mainly in rheumatoid arthritis MSCs. MSC interaction with B cells provides stimuli for B-cell survival and therefore may contribute to the pathogenesis of rheumatoid arthritis. MSC-derived factors other than B cell-activating factor are likely to contribute to this effect. This feature is more prominent in rheumatoid arthritis MSCs, possibly due to the B cell-activating factor.

B cell activating factor, its role in autoimmunity, and targeting in autoimmune diseases.

B cell activation factor (BAFF), a recently identified member of the tumour necrosis factor (TNF) family, is a key survival factor during B cell maturation and is essential for the development of B cell tolerance. Breakdown of the regulation of BAFF expression results in excessive BAFF production that impairs B cell tolerance and leads to autoimmune phenomena. Consistent with this, BAFF levels are elevated in plasma of patients with various autoimmune diseases. BAFF is considered to be one of the principal factors that regulate the size and composition of B cell compartment. BAFF acts as an important driving factor for B cell hyperplasia and autoantibody production in autoimmune processes. Thus BAFF has become a very attractive target for the treatment of autoimmune diseases with an altered B cell function. Results of clinical trials have confirmed a crucial role of BAFF in the pathogenesis of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). BAFF inhibitors in the treatment of RA, SLE and other autoimmune diseases are under intensive investigation. However, BAFF biology remains poorly understood. Nonetheless, results of the ongoing studies may enable the development of a new generation of BAFF inhibitors with more selective efficacy and increased safety (Fig. 2, Ref. 92). Full Text (Free, PDF) www.bmj.sk.

Decreased expression of integrins by hematopoietic cells in patients with rheumatoid arthritis and anemia: relationship with bone marrow cytokine levels.

BACKGROUND AND OBJECTIVES: In order to gain a better insight into the pathogenesis of the anemia of chronic disease (ACD) accompanying rheumatoid arthritis, we analyzed the density of the integrins very late antigen (VLA) 4 and VLA-5 on the surface of erythroblasts from bone marrow in patients with rheumatoid arthritis. We also measured the concentration of interleukin (IL) 3 and tumor necrosis factor (TNF) alpha in bone marrow. Finally, we analyzed the relationship between integrin expression on hematopoietic cells and the degree of anemia and concentration of cytokines in bone marrow in patients with rheumatoid arthritis. RESULTS: Patients with rheumatoid arthritis who also had ACD were found to have lower hemoglobin levels and higher C-reactive protein and erythrocyte sedimentation rate compared to patients who had rheumatoid arthritis without ACD or osteoarthritis of the hip. The mean bone marrow concentration of IL-3 was elevated in patients with rheumatoid arthritis and ACD compared to those without ACD or patients with osteoarthritis. IL-3 concentration in bone marrow showed a significant negative correlation with VLA-4 and VLA-5 expression on erythroblasts, but only in patients with rheumatoid arthritis and ACD. CONCLUSION: Patients with rheumatoid arthritis and ACD have abnormal erythroblasts (decreased VLA density), possibly through an effect on early stages of erythroblast development. Increased levels of IL-3 and the negative correlation between IL-3 concentration in bone marrow and expression of the integrins VLA-4 and VLA-5 may suggest positive feedback between erythroblasts and IL-3, probably associated with decreased sensitivity of bone marrow erythroblasts to IL-3.

Heme oxygenase-1 participates in the anti-inflammatory activity of taurine chloramine.

Interleukin-6 (IL-6) and interleukin-8 (IL-8) are implicated in the pathogenesis of rheumatic diseases. In affected joints fibroblast-like synoviocytes (FLS) are the major source of these pro-inflammatory cytokines. We have previously found that production of both cytokines is inhibited in vitro by taurine chloramine (Tau-Cl). Heme oxygenase (HO-1) activity was also reported to restrict synthesis of various inflammatory mediators, including IL-6 and IL-8. The aim of present study was to investigate whether this enzyme activity is implicated in the mechanism of Tau-Cl suppressive effect. We have shown that in rheumatoid FLS both hemin (known HO-1 inducer) and Tau-Cl significantly up-regulate HO-1 expression at the mRNA and protein levels and simultaneously inhibit IL-1 beta-triggered production of pro-inflammatory cytokines. However, the inhibitory potency of these compounds differs, because hemin is more potent inhibitor of IL-8 than IL-6 production, while Tau-Cl exerts opposite effect. Importantly, pretreatment of the cells with HO-1 inhibitor completely reverses the inhibitory effect of hemin on both cytokines production. However, in Tau-Cl treated cells this inhibitor fully restores only IL-8 secretion but has weaker effect on IL-6 response. Thus, the present results: (i) support HO-1 activity to be relevant to negatively control production of pro-inflammatory cytokines, and (ii) underline implication of HO-1 in mediating Tau-Cl inhibitory action.

The role of cytokines in inflammatory response after total knee arthroplasty in patients with rheumatoid arthritis.

Surgery and trauma is accompanied by changes in blood levels of certain cytokines and chemokines including interleukin-6 (IL-6) and interleukin-8 (IL-8). However, there is little data on correlations between local and systemic levels of these mediators during orthopedic surgeries in rheumatoid arthritis (RA) patients who already show increased levels of proinflammatory cytokines due to their disease. We aimed to measure dynamics of blood and drainage fluid levels of IL-6 and IL-8 in postoperative period in rheumatoid arthritis patients undergoing knee replacement surgery and correlate these changes with blood levels of C-reactive protein (CRP), body temperature and pain. We report that blood and drainage fluid levels of IL-6 and IL-8 showed significantly increasing trend during the 36-h period after the surgery. Drainage fluid levels of both cytokines were significantly higher in comparison with blood, indicating their local production in the operated joint. In contrast, levels of CRP were higher in blood than in drainage fluid. Despite the fact that the levels of tested cytokines had already been high in RA patients before surgery, we conclude that after surgery their levels were being much significantly enough high in drainage fluid to reflect dominated local inflammatory reaction to surgical stress and trauma.

Is Taurolidine a candidate for treatment of rheumatoid arthritis?

OBJECTIVE: To study the therapeutic potential of taurolidine (TRD), a derivative of taurine with known anti-inflammatory and anti-proliferative properties, in various experimental models of synovitis. METHODS: In vitro: fibroblast-like synoviocytes (RA FLS) isolated from the synovial tissue of patients with rheumatoid arthritis (RA) were cultured in the presence of either TRD or polyvinylpyrrolidine (PVP), the pharmaceutical stabilizer of TRD, which was used as a control. Proliferation of RA FLS and cytokine (IL-6 and IL-8) release were measured. In vivo: (A). The effect of systemic TRD treatment on the development of collagen-induced arthritis (CIA) in female DBA1/J mice was investigated. Mice were treated either with intraperitoneal injections of 1 ml of 2% Taurolin Boehringer Ingelheim (TRD +PVP) or with PVP as placebo. The incidence of arthritis, myeloperoxidase (MPO) activity in periarticular tissue, as well as serum concentration of IgG specific to collagen II (IgG alphaCII) were determined. (B). The effect of intra-articular TRD treatment was studied in rabbits with antigen-induced monoarthritis (AIA). After the induction of AIA of right knees rabbits were treated either with intra-articular injections of 0.5 ml of 2% Taurolin or 0.5ml PVP ( placebo). The animals were examined for clinical signs of arthritis and diameter of joints was measured. After termination of the experiment, the arthritic knees were examined and histopathology of the joints was assessed. In addition, serum amyloid A (SAA) concentration was measured. RESULTS: n vitro: TRD exerted cytotoxic effect on RA FLS when applied at concentrations >100 microM. TRD at non-cytotoxic concentrations, inhibited PDGF-triggered RA FLS proliferation, reduced IL-1beta - stimulated production of IL-6 and slightly decreased intracellular content of IL-8. In vivo: (A). Intraperitoneal treatment with Taurolin significantly reduced the incidence (30%) of CIA when compared to the control mice (79%). However, Taurolin failed to control the development of CIA in mice with high serum level of IgG alphaCII (>1000 U).(B). Intra-articular application of 2% Taurolin resulted in amelioration of AIA in all treated rabbits (reduced diameter of arthritic joints and smaller rise of SAA level as compared to the control animals). Histopathologic evaluation revealed pannus formation in both groups and extensive necrotic lesions of synovial tissue treated with TRD, suggesting synoviorthesis-like effect. CONCLUSION: Results from AIA and from in vitro RA FLS studies suggest that intra-articular administration of TRD could be used as a "pharmacological scalpel" to remove the inflamed synovium. Our data confirmed anti-inflammatory and anti-proliferative properties of TRD in all experimental models encouraging further studies which should evaluate its therapeutic potential in RA.

Enhanced expression of mineralocorticoid receptors in the heart after the myocardial infarct in rats.

Increasing evidence suggests that enhanced stimulation of the heart and kidney by mineralocorticoids plays significant role in development of the post-infarct cardiac failure. Because increased synthesis of mineralocorticoid receptors (MR) is one of the putative factors determining pathogenic effects of mineralocorticoids we decided to determine whether the myocardial infarct results in an enhanced expression of MR mRNA and MR protein. To this end male Sprague-Dawley rats were subjected either to ligation of the left coronary artery or to sham surgery. After four weeks expressions of MR mRNA and MR protein were evaluated in both groups of rats in the left (LV) and right (RV) ventricle walls, and in the renal cortex and renal medulla by means of semiquantitative PCR and Western blotting methods. Coronary ligation resulted in the myocardial infarction encompassing 30.2% +/- 1.9% (range 23-40%) of the left ventricle wall. In the infarcted rats expression of MR mRNA was significantly greater than in the sham-operated rats, both in the LV (P<0.02) and in the RV (P<0.005). In the left but not in the right ventricle increased MR mRNA expression was associated with significant increase in expression of MR protein (P<0.001). In the renal cortex and renal medulla MR mRNA and MR protein expression in the infarcted and the sham-operated rats did not differ. The study reveals that during the post-infarct state expression of MR mRNA is elevated in both cardiac ventricles while expression of MR mRNA protein is increased only in the left ventricle. The results suggest that the enhanced expression of mineralocorticoid receptors may contribute to enhanced effects of mineralocorticoids in the heart during the post-infarct state.

Comparison of taurine chloramine and taurine bromamine effects on rheumatoid arthritis synoviocytes.

Fibroblast-like synoviocytes (FLS) participate in rheumatoid arthritis (RA) chronic synovitis by producing pro-inflammatory cytokines (IL-6, IL-8), growth factors (VEGF) and other inflammatory mediators (PGE2, NO). We have previously reported that Tau-Cl, generated by neutrophils, inhibits in vitro some of these pathogenic RA FLS functions. Taurine bromamine (Tau-Br) originates from eosinophils and neutrophils, and its immunoregulatory activities are poorly known. Therefore, we investigated the effects of Tau-Br on RA FLS functions and compared it to Tau-Cl anti-inflammatory action. When applied at noncytotoxic concentrations: (i) Tau-Br inhibited IL-6 and PGE2 production with potency similar to Tau-Cl (IC50 approximately 250 microM), (ii) Tau-Br failed to affect VEGF and IL-8 synthesis, while Tau-Cl exerted inhibitory effect (IC50 approximately 400 microM), (iii) none of these compounds affected NO generation and iNOS expression. Thus, Tau-Cl is more effective than Tau-Br in normalization of pro-inflammatory RA FLS functions.

Taurine chloramine inhibits proliferation of rheumatoid arthritis synoviocytes by triggering a p53-dependent pathway.

OBJECTIVE AND DESIGN: Taurine chloramine (Tau-Cl), originating from activated neutrophils, possesses antiinflammatory activities. Fibroblast-like synoviocytes (FLS) participate in the chronic synovitis and synovial membrane hyperplasia that are characteristic pathological features of rheumatoid arthritis (RA). The present study was conducted to investigate the mechanism of the Tau-Cl effect on the proliferation of these cells in culture. MATERIALS AND METHODS: FLS were stimulated in vitro with platelet derived growth factor (PDGF) alone or together with Tau-Cl. Cell proliferation was evaluated by counting the total and dividing cell numbers and by measurement of (3)H-thymidine incorporation. Expression of the key cell-cycle regulators was evaluated at the protein (Western blotting) and/or mRNA (RT-PCR) levels. RESULTS: Treatment of RA FLS with Tau-Cl (200-500 microM) resulted in an early nuclear accumulation of p53 tumor suppressor protein. Moreover, Tau-Cl inhibited PDGF-triggered cell proliferation (IC(50) value approximately 250-300 microM), accompanied by characteristic modulation of p53 transcriptional targets: down-regulation of proliferating cell nuclear antigen (PCNA) and survivin, and concomitant up-regulation of p21 mitotic inhibitor. CONCLUSION: We propose that Tau-Cl inhibits proliferation of RA FLS by triggering a p53-dependent cell-cycle arrest and conclude that this compound suppresses pathways in FLS that are known to contribute to the pathology of RA.

Expression of mineralocorticoid receptors mRNA in the brain, heart and kidney of Sprague Dawley rats with renovascular hypertension.

A large body of evidence indicates that mineralocorticoids play significant role in regulation of cardiovascular functions and in pathogenesis of several forms of hypertension by means of multiple effects exerted in the brain, heart and kidney. However, little is known about regulation of expression of mineralocorticoid receptors mRNA in the hypertensive states. The purpose of the present study was to determine whether expression of mineralocorticoid receptors mRNA is altered in the brain as well as in the left ventricle of the heart and in the kidney in the rats with the Goldblatt 2K,1C renovascular hypertension. Competitive PCR method was used for relative quantitative analysis of mineralocorticoid receptors mRNA in the brain, heart and kidney samples harvested from 12 to 14 weeks old, male Sprague Dawley rats subjected either to constriction of the left renal artery (n=8) or to the sham surgery (n=9). The 2K,1C rats manifested significantly higher systolic blood pressure (P<0.005) and significantly reduced weight of the left kidney (P<0.001) in comparison to the sham-operated rats. In both groups, mineralocorticoid receptors mRNA was well expressed in the preoptic, diencephalic, mesencephalopontine, medullary and cerebellar regions of the brain, and in the heart, renal cortex and the renal medulla. Significant differences were found between expression of MR mRNA in different brain regions. In the 2K,1C rats, expression of mineralocorticoid receptors mRNA was significantly lower than in the sham-operated rats in the mesencephalopontine (P<0.02) and medullary (P<0.005) regions of the brain as well as in the heart (P<0.030) and the renal medulla of the kidney (P<0.001). No significant differences were detected in the other brain regions and in the renal cortex. The results provide evidence that mineralocorticoid receptors mRNA expression is significantly diminished in the brain stem, the heart and the renal medulla of rats with the 2K,1C renovascular hypertension.

Is there a role of taurine bromamine in inflammation? Interactive effects with nitrite and hydrogen peroxide.

OBJECTIVE AND DESIGN: The myeloperoxidase system of neutrophils generates chlorinating and brominating oxidants in vivo. The major haloamines of the system are taurine chloramine (TauCl) and taurine bromamine (TauBr). It has been demonstrated in vitro that TauCl exerts both antiinflammatory and anti-bacterial properties. Much less is known about TauBr. The present study was conducted to compare bactericidal and immunoregulatory capacity of TauBr with that of the major chlorinating oxidants: HOCl and TauCl. Moreover, the effect of nitrites and H(2)O(2) on TauBr activity was investigated. MATERIALS: TauBr was prepared by reaction of HOBr with taurine. The reaction was monitored by UV absorption spectra. METHODS: Bactericidal activity of TauBr, TauCl and HOCl was tested by incubation of E. coli with the compounds and determined by the pour-plate method. To test the anti-inflammatory activity the compounds were incubated with LPS and IFN-gamma stimulated murine peritoneal macrophages. The production of following mediators was measured: nitrites by Griess reaction; TNF-alpha, IL-6, IL-10, IL-12p40 using capture ELISA. In some experiments the compounds were incubated with either nitrites or H(2)O(2). RESULTS: In our experimental set-up TauBr and HOCl exerted strong bactericidal effects on E. coli (MBC = 110 microM and 8 microM, respectively), while TauCl (< 1000 microM) did not kill test bacteria. However, both, TauBr and TauCl, at noncytotoxic concentrations (< 300 microM) inhibited the cytokine and nitric oxide production by macrophages. H(2)O(2) completely abolished the biological activities of TauBr but not those of TauCl. Nitrites did not affect any activity of TauBr or TauCl while they diminished the HOCl(-) mediated bacterial killing. CONCLUSION: TauBr, despite very low concentration of Br(-) in body fluids, may support TauCl and HOCl in the regulation of inflammatory response and in killing of bacteria by neutrophils. However, TauBr activity in vivo will depend on the presence of H(2)O(2) and possible other mediators of inflammation which can compete with target molecules for TauBr.

The effect of taurine chloramine on pro-inflammatory cytokine production by peripheral blood mononuclear cells isolated from rheumatoid arthritis and osteoarthritis patients.

OBJECTIVE: Pro-inflammatory cytokines play a critical role in the pathogenesis of RA. A natural oxidant, TauCl exerts anti-inflammatory activities. Here, the effects of Tau and TauCl on key pro-inflammatory cytokines--IL-1beta, IL-6 and TNF-alpha production by LPS-triggered peripheral blood mononuclear cells (PBMCs) isolated from RA and OA patients and healthy blood donors--were examined. METHODS: PBMCs were stimulated with LPS (24 h) in the presence of Tau or TauCl (200-400 microM). Cytokine production was measured in culture supernatants (secreted) and cells lysates (cell-associated) using specific ELISAs. RESULTS: Production of the secretedforms of IL-1beta and IL-6 was inhibited by TauCl with IC50 approximately equal to 250 microM and 300-400 microM respectively, in all investigated groups. In all cultures of PBMCs TauCl raised the TNF-alpha production at the low concentration (200 mM), while at the higher concentration (400 microM) either reduced it (55% of RA, 70% of OA patients and 55% of healthy donors) or exerted no effect (remainder of patients). Interestingly, Tau did not significantly affect any cytokine production. CONCLUSION: TauCl at high concentrations down-regulates pro-inflammatory cytokine production. However, the impact of TauCl on TNF-alpha production by PBMCs from RA is more limited than in cells isolated from OA patients.

Differential expression of vasopressin V1a and V1b receptors mRNA in the brain of renin transgenic TGR(mRen2)27 and Sprague-Dawley rats.

Recent evidence indicates that renin transgenic rats TGR(mRen2)27 (TGR) manifest increased activity of the central vasopressinergic system. Because one of the reasons for this finding could be an increased synthesis of vasopressin receptors, we determined in the present study expression of V1a and V1b vasopressin receptors (R) mRNA in the brain of TGR rats and of their parent Sprague-Dawley (SD) strain. Competitive PCR method was applied for quantitative analysis of V1a and V1b receptors mRNA in the preoptic, diencephalic, mesencephalopontine and medullary regions. V1aR mRNA expression was similar in SD and TGR rats in the preoptic, diencephalic and mesencephalopontine regions. In the medullary region expression of V1aR mRNA was significantly lower in TGR than in SD rats. V1bR mRNA did not differ in TGR and SD rats in the preoptic, diencephalic and medullary region whereas it was significantly elevated in the mesencephalopontine region. The results provide evidence for differential regulation of V1a and V1b receptors genes in the brain stem of TGR rats that is manifested by downregulation of V1aR mRNA in the medulla and upregulation of V1bR mRNA in the mesencephalopontine region.

Taurine chloramine modulates cytokine production by human peripheral blood mononuclear cells.

The effect of taurine (Tau) and taurine chloramine (Tau-Cl) on the production of TNF- alpha, IL-1 beta, and IL-6 by peripheral blood mononuclear cells of healthy volunteers was examined. Cells were stimulated with bacterial lipopolysaccharide (LPS) in the presence of either Tau or Tau-Cl. After 24 h culture the cytokine concentrations were measured in both culture supernatants (secreted) and cell lysates (cell-associated) using ELISA. In LPS-stimulated cells Tau-Cl inhibited both the secreted and cell-associated IL-1 beta and IL-6, while exerted dual effect on TNF- alpha production: raising it slightly at low and reducing at higher concentration. By contrast, Tau had no significant effect on the cytokine production. These results indicate that Tau-Cl modulates synthesis of pro-inflammatory cytokines, and therefore it may play a role in the initiation and propagation of immune response.

Impaired generation of taurine chloramine by synovial fluid neutrophils of rheumatoid arthritis patients.

Taurine (Tau), a dominant free amino acid present in neutrophil cytoplasm, serves as a scavenger for hypochlorous acid (HOCl) released during these cells activation. The resulting taurine chloramine (Tau-Cl) exerts potent anti-inflammatory properties. In the present study we tested the hypothesis that the formation of Tau-Cl is impaired in neutrophils isolated from rheumatoid arthritis (RA) patients. The inhibition of zymosan-triggered chemiluminescence in the presence of exogenous Tau was used for indirect measurement of Tau-Cl generation. The chemiluminescence of neutrophils isolated from peripheral blood (PB) of healthy volunteers and RA patients was inhibited by Tau with similar potency. By contrast, synovial fluid (SF) neutrophils of these patients were significantly less sensitive for Tau-mediated inhibition. Therefore, our data indicate impaired generation of Tau-Cl in neutrophils isolated from SF of RA patients.

Effect of taurine chloramine, the product of activated neutrophils, on the development of collagen-induced arthritis in DBA 1/J mice.

Taurine chloramine (TauCl), a product of neutrophil myeloperoxidase - halide system, formed by a reaction of taurine with HOCl, is known as an anti-microbial and anti-inflammatory long-lived oxidant. We previously reported that TauCl inhibits in vitro the production of proinflammatory cytokines (IL-6, IL-8) by RA synoviocytes. Therefore we performed this study to investigate the effect of TauCl treatment on the development of collagen-induced arthritis (CIA) in DBA1/J mice. Early administration of TauCl (after primary immunization) resulted in the delay of the onset of CIA, but had no effect on severity of arthritis. TauCl, given daily for 21 days after booster immunization, did not reduce the symptoms of arthritis in those mice, which already developed CIA, but significantly diminished incidence of the disease (55% vs. 90% of placebo mice). The mechanism of this effect is unknown. This is the first in vivo study suggesting that TauCl may be used for immune intervention in chronic inflammatory diseases.

Vasopressin V1a, V1b and V2 receptors mRNA in the kidney and heart of the renin transgenic TGR(mRen2)27 and Sprague Dawley rats.

Vasopressin plays significant role in regulation of blood pressure by means of V1 and V2 receptors, however regulation of synthesis of these receptors in hypertension is only poorly recognized. The purpose of the present study was to compare expression of V1a, V1b and V2 vasopressin (R) mRNA in the renal cortex, renal medulla and the heart of hypertensive renin transgenic TGR(mRen2)27 rats (TGR) and of their parent normotensive Sprague Dawley (SD) strain. The study was performed on 12 weeks old TGR and SD rats. Competitive PCR method was used for quantitative analysis of V1a, V1b and V2 receptors mRNA in fragments of renal cortex, renal medulla and apex of the left ventricle of the heart. In both strains expression of V1aR and V2R mRNA was significantly greater in the renal medulla than in the renal cortex. In the renal medulla but not in the cortex expression of V1aR mRNA was significantly greater in TGR than in SD rats. V2R mRNA expression was similar in the renal cortex and renal medulla of both strains. V1aR mRNA was well expressed in the heart of SD and TGR rats, however there was no significant difference between these two strains. V2R mRNA was not present in the heart. V1bR mRNa could not be detected either in the kidney or in the heart. The results provide evidence for specific increase of expression of V1a receptors mRNA in the renal medulla of TGR rats.

Expression of IL-15 and IL-15 receptor isoforms in select structures of human fetal brain.

IL-15, a key cytokine linking innate and acquired immunity, is expressed in many cell types and tissues. Recent data indicate constitutive expression of IL-15 in human neural cell lines and tissues. The aim of the present study was to examine the expression patterns of mRNA encoding IL-15 and IL-15 receptor alpha (IL-15Ralpha) isoforms in select structures of human fetal brain. We report that mRNA for IL-15 and IL-15Ralpha isoforms were expressed in all tested brain structures: cerebral cortex, cerebellum, hippocampus, and thalamus. However, the levels of IL-15 and IL-15Ralpha mRNA were higher in the hippocampus and cerebellum in comparison with cortex and thalamus. Moreover, higher levels of cytosol in comparison with membrane-bound IL-15 isoform were present in all brain structures. The constitutive, but distinct, expression of IL-15 and its receptors in select human fetal brain structures suggests that IL-15 plays a role in their development and physiology.