Yasunori Matsuki

Stimulation with thromboxane A2 (TXA2) receptor agonist enhances ICAM-1, VCAM-1 or ELAM-1 expression by human vascular endothelial cells

A previous study reported that intercellular adhesion molecule‐1 (ICAM‐1) expression by human vascular endothelial cells (HUVEC) is augmented by intracellular signal transmission mainly through the protein kinase C (PKC) system stimulated by TXA2 receptors. In the present study, we show that a TXA2 receptor agonist, U46619, augments the expression of not only ICAM‐1, but also vascular cell adhesion molecule‐1 (VCAM‐1) or endothelial leucocyte adhesion molecule‐1 (ELAM‐1) in HUVEC both at protein and mRNA levels. Pretreatment with SQ29,548 (a TXA2 receptor antagonist) or PKC inhibitors greatly diminished the extent of U46619‐induced mRNA accumulation and surface expression of the adhesion molecules. An inhibitor of nuclear factor κB (NF‐κB) activation, PDTC, diminishes U46619‐induced VCAM‐1 mRNA accumulation. NAC, which inhibits NF‐κB and activation protein 1 (AP‐1) binding activity, inhibits the expression of ICAM‐1 or ELAM‐1 at protein and mRNA levels. These findings suggest that ICAM‐1 or ELAM‐1 expression of HUVEC stimulated via TXA2 receptors is augmented by induction of NF‐κB and AP‐1 binding activity through the PKC system, and that VCAM‐1 expression is augmented by induction of NF‐κB binding activity.

Filtration leukocytapheresis therapy in rheumatoid arthritis: A randomized, double‐blind, placebo‐controlled trial

OBJECTIVE To determine the efficacy and safety of filtration leukocytapheresis (LCP) for the treatment of rheumatoid arthritis (RA). METHODS Twenty-five patients with drug-resistant RA were randomly assigned to undergo filtration LCP and 7 to undergo sham apheresis (control group) in a randomized, double-blind, placebo-controlled study. Three apheresis procedures were performed, with 1-week intervals between procedures. The efficacy of filtration LCP was evaluated according to the American College of Rheumatology definition of improvement in RA. Medications for each patient were unchanged for at least 6 months prior to enrollment and throughout the study. RESULTS Tender joint counts, swollen joint counts, patient assessment of pain and global severity, physician assessment of global severity, and Health Assessment Questionnaire Disability Index were significantly improved in the LCP group compared with the control group (P < 0.05 for patient assessment of pain; P < 0.01 for all others). Seventy-nine percent of the patients in the LCP group exhibited significant overall improvement, while none of the patients in the control group were improved (P < 0.001). CONCLUSION The results indicate that filtration LCP is an effective and well-tolerated treatment for patients with drug-resistant RA.

Thromboxane A2 receptor blockade suppresses intercellular adhesion molecule-1 expression by stimulated vascular endothelial cells

Inhibition of the thromboxane A2-synthesizing enzyme (DP-1904: [+/-]-6-[1-imidazolylmethyl]-5,6,7,8-tetrahydronaphthalene-2-carbo xylic acid hydrochloride hemihydrate) reportedly suppresses intercellular adhesion molecule-1 (ICAM-1) expression on the surface of stimulated vascular endothelial cells (Ishizuka et al., 1994, Eur. J. Pharmacol 262, 113). In the present study, thromboxane A2 receptor antagonists suppressed the expression of ICAM-1 on the surface of human vascular endothelial cells that were stimulated by tumor necrosis factor alpha (TNF alpha), platelet activating factor (PAF), or U46619 (9,11-dideoxy-9 alpha, 11 alpha-epoxymethanoprostaglandin F2 alpha). Augmentation of ICAM-1 expression on human vascular endothelial cells stimulated by U46619 was suppressed by protein kinase C inhibitors. Thromboxane A2 receptor antagonist suppressed U46619 stimulation of protein kinase C activity of a cell membrane fraction. These results indicate that in human vascular endothelial cells, thromboxane A2, the production and secretion of which is stimulated by TNF alpha or PAF, binds to the thromboxane A2 receptors on cell membranes and augments ICAM-1 expression on the cell surfaces mainly through protein kinase C.

Hyaluronan production in human rheumatoid fibroblastic synovial lining cells is increased by interleukin 1β but inhibited by transforming growth factor β1

OBJECTIVES To investigate the regulatory roles of interleukin 1β (IL1β), tumour necrosis factor α (TNFα), interferon γ (IFNγ) or transforming growth factor β1 (TGFβ1) on hyaluronan (HA) synthesis by human fibroblastic synovial lining cells. METHODS Concentrations of HA in culture supernatants of fibroblastic synovial lining cell line (RAMAK-1 cell line) with or without stimulation by IL1β, TNFα, IFNγ or TGFβ1 were measured by sandwich binding protein assay. Levels of HA synthase mRNA of the cells with or without stimulation were detected by reverse transcribed polymerase chain reaction. Molecular weights of HA in the culture supernatants of the cells with or without stimulation were measured using high performance gel permeation liquid chromatography. RESULTS HA synthesis by the cells was not significantly augmented by TNFα or by IFNγ. It was significantly stimulated by IL1β but inhibited by TGFβ1. Molecular weights of HA in the culture supernatants of the cells were unchanged by stimulation with TNFα. They were remarkably increased by stimulation with IL1β and IFNγ, but reduced with TGFβ1. CONCLUSION IL1β is an up regulator of HA synthesis, while TGFβ1 is a down regulator. HA production in the synovial lining cells of inflamed joints (for example, rheumatoid arthritis) might be regulated by the balance of these cytokines.

DP-1904, a specific inhibitor of thromboxane A2 synthesizing enzyme, suppresses ICAM-1 expression by stimulated vascular endothelial cells

Intercellular adhesion molecule-1 (ICAM-1) is an antigen that is strongly expressed by vascular endothelial cells at sites of local inflammation and participates in the development of inflammation. In the present study, vascular endothelial cells were stimulated by inflammatory cytokines that promote thromboxane A2 synthesis to observe their effects on the expression and shedding of ICAM-1 on the cell surface. In addition, the suppressive effects of DP-1904 ([+/-]-6-[1-imidazolylmethyl]-5,6,7,8-tetrahydronaphthalene-2- carboxylic acid hydrochloride hemihydrate), a thromboxane A2 synthesis inhibitor, on ICAM-1 expression were evaluated. ICAM-1 expression on the surface of human umbilical vein endothelial cells was increased significantly by stimulation with interleukin-1 beta, tumor necrosis factor alpha (TNF alpha), thrombin and platelet-activating factor (PAF). DP-1904, an inhibitor of thromboxane A2 synthesis, significantly suppressed the expression of ICAM-1 on the surface of human vascular endothelial cells that had been stimulated by TNF alpha or PAF. These findings suggest that an enhanced expression of thromboxane A2 on human vascular endothelial cells is closely related to the expression of ICAM-1 on the surface of these cells.

Primary Sjögren's Syndrome Associated with Hyaline-vascular Type of Castleman's Disease and Autoimmune Idiopathic Thrombocytopenia

We describe a case of primary Sjögrens syndrome complicated by hyaline-vascular type of Castlemans disease and autoimmune idiopathic thrombocytopenia. This type of Castlemans disease was diagnosed by biopsy of a right axillary lymph node 7 years after the onset of Sjögrens syndrome. The specimen showed small hyaline-vascular lymphoid follicles and interfollicular capillary proliferation. Serum IL-6 was slightly increased, but systemic manifestations, such as fever or weight loss, were not present. Hyaline-vascular type of Castlemans disease should be considered a lymphoproliferative disorder associated with Sjögrens syndrome.

Anti-DNA antibody kinetics following selective removal by adsorption using dextran sulphate cellulose columns in patients with systemic lupus erythematosus

The aim of this study is to determine by mathematical analysis which of two models, the one‐ or the two‐compartment model, more closely approximates the kinetics of anti‐dsDNA following immunoadsorption procedures in patients with systemic lupus erythematosus. Titers of anti‐dsDNA were measured at specified intervals after apheresis to each model by nonlinear least‐squares methods, and Akaikes Information Criterion (AIC) was calculated to determine which model most approximately described the kinetics.

The Novel Murine CD4+CD8+ Thymocyte Cell Line Exhibits Lineage Commitment into Both CD4+ and CD8+ T Cells by Altering the Intensity and the Duration of Anti-CD3 Stimulation In Vitro

A CD4+CD8+ double-positive thymocyte cell line, 257-20-109 was established from BALB/c mice thymocytes and used to analyze the requirements to induce CD4 or CD8 single-positive (SP) T cells. CD4SP cells were induced from 257-20-109 cells by anti-CD3 stimulation in the presence of the FcR-positive macrophage cell line, P388D1. During stimulation, maturation events, such as the down-regulation of CD24 and the up-regulation of CD69, H-2Dd, CD5, and Bcl-2, were recognized. Furthermore, these CD4SP cells appeared to be functional because the cells produced IL-2 and IL-4 when activated with phorbol ester and calcium ionophore. In contrast, CD8SP cells could be induced by stimulation with fixed anti-CD3 after removal of stimulation. To investigate the extent of signals required for CD4SP and CD8SP, the cells stimulated under either condition for 2 days were sorted and transferred to different culture conditions. These results suggested that the fate of lineage commitment was determined within 2 days, and that CD4 lineage commitment required longer activation. Furthermore, the experiments with subclones of 257-20-109 demonstrated that the lower density of CD3 did not shift the cells from CD4SP to CD8SP, but only reduced the amount of CD4SP cells. In contrast, when the 257-20-109 cells were stimulated by the combination of fixed anti-CD3 and anti-CD28, the majority of the cells shifted to CD4SP, with an enhancement of extracellular signal-regulated kinase 1 phosphorylation. Our results indicate that the signals via TCR/CD3 alone shifted the double-positive cells to CD8SP cells, but the reinforced signals via TCR/CD3 and costimulator could commit the cells to CD4SP.

Adsorption of anaphylatoxins from the plasma of systemic lupus erythematosus patients using dextran sulfate cellulose columns

Complement‐derived anaphylatoxin may be one of the causes of vascular injury and an indicator of activity in systemic lupus erythematosus (SLE). The present study examines the effectiveness of dextran sulfate (DS) column immunoadsorption treatment to remove anaphylatoxins (C3a, C4a, and C5a) from the blood of patients with SLE. Seven SLE patients were subjected to immunoadsorption using DS‐bound cellulose columns (Selesorb®, Kaneka). Blood samples were taken both before and after the immunoadsorption session. Specimens were also obtained from both the inlets and outlets of the DS columns every 1,000 ml of treated plasma volume. The DS columns removed anaphylatoxins C3a and C4a from the separated plasma (from 775 ± 334 ng/ml to 640 ± 252 ng/ml, and from 1,303 ± 847 ng/ml to 619 ± 578 ng/ml, respectively) during the clinical anti‐DNA apheresis procedure. In these study, the C5a levels in the circulating plasma of SLE patients were not elevated. To confirm whether DS‐bound cellulose beads adsorbs anaphylatoxins in vitro, zymosan‐activated plasma (ZAP) containing high levels of anaphylatoxins was incubated with DS‐bound cellulose beads. The levels of C3a, C4a and C5a in the ZAP significantly decreased by mixing with DS‐bound cellulose beads (P < 0.05). Nevertheless, C3a and C4a in the peripheral blood were not significantly decreased after the immunoadsorption, suggesting that these anaphylatoxins bypass the DS columns in apheresis and return to the patient via the cell‐rich fraction. J. Clin. Apheresis 13:108–113, 1998.

Anti-dsDNA antibody kinetics during in vivo apheresis in systemic lupus erythematosus patients and in an in vitro apheresis model

Levels of anti‐dsDNA measured just after an immunoadsorption procedure in systemic lupus erythematosus (SLE) patients are sometimes paradoxically larger than those measured just before the procedure. A 1:100 in vitro single‐compartment immunoadsorption system model was devised to determine which of two models, one‐ or two‐compartment, more closely approximates the kinetics of anti‐dsDNA during apheresis procedures. Ten SLE patients were employed in this study. A total of 4,100 ml of plasma was passed through the dextran sulfate cellulose columns during one clinical apheresis session. In eight of ten patients, the log of RIA‐measured anti‐dsDNA titers decreased linearly as treated plasma volume increased, in both the clinical procedure and the experimental model. The mean adsorption efficacy in the clinical apheresis procedure and in the in vitro model was 0.37 and 0.27, respectively. However, in one patient the RIA‐measured level of anti‐dsDNA increased during the apheresis procedure; this phenomenon was mirrored in the model (definitely a single pool model). In contrast, the level of anti‐dsDNA, as measured by ELISA, decreased in accordance with the increase of treated plasma volume in both the clinical and the in vitro apheresis procedures. Therefore, an increased titer of anti‐dsDNA as measured by RIA immediately following clinical apheresis cannot be accounted for exclusively by an inflow of antibodies from a secondary (extravascular) pool into the circulating plasma. In short, a one‐compartment model is applicable and an explanation must be sought elsewhere.