A phase 2 randomized, double-blind, placebo-controlled study of the effect of VIA-2291, a 5-lipoxygenase inhibitor, on vascular inflammation in patients after an acute coronary syndrome.

OBJECTIVE: Arachidonate 5-lipoxygenase (5-LO) is a key enzyme in the synthesis of leukotrienes. VIA-2291 is a potent 5-LO inhibitor, which has been shown to reduce hsCRP and noncalcified coronary plaque volume following an acute coronary syndrome (ACS). We aim to evaluate the effect of VIA-2291 on vascular inflammation compared to placebo using FDG-PET. METHODS: A Phase II, randomized, double-blind, parallel-group study was conducted in 52 patients with recent ACS assigned 1:1 to either 100 mg VIA-2291 or placebo for 24 weeks. The primary outcome was the effect of VIA-2291 relative to placebo on arterial inflammation detected by (18)fluorodeoxyglucose positron emission tomography (FDG-PET) within the index vessel after 24 weeks of daily treatment, compared to baseline. RESULTS: VIA-2291 was relatively well tolerated and was associated with a significant inhibition of the potent chemo-attractant LTB4, with a mean inhibition of activity of 92.8% (p<0.0001) at 6 weeks in the VIA-2291 group, without further significant change in inhibition at 24 weeks. However, for VIA-2291 was not associated with significant difference in inflammation (target-to-background ratio) compared to placebo at 24 weeks or 6 weeks of treatment. Further, VIA-2291 was not associated with a significant reduction in hsCRP from baseline after either 6 or 24 weeks of treatment. CONCLUSIONS: VIA-2291 is well-tolerated and effectively reduces leukotriene production. However, inhibition of 5-LO with VIA-2291 is not associated with significant reductions in vascular inflammation (by FDG-PET) or in blood inflammatory markers. Accordingly, this study does not provide evidence to support a significant anti-inflammatory effect of VIA-2291 in patients with recent ACS.

Treatment with 5-lipoxygenase inhibitor VIA-2291 (Atreleuton) in patients with recent acute coronary syndrome.

BACKGROUND: Production of leukotrienes by 5-lipoxygenase (5-LO) has been linked to unstable atherosclerotic plaques and cardiovascular events. VIA-2291 is a potent 5-LO inhibitor. METHODS AND RESULTS: In a double-blinded study, 191 patients were randomly assigned 3 weeks after an acute coronary syndrome to receive 25, 50, or 100 mg VIA-2291 or placebo daily for 12 weeks. The primary study end point, whole blood stimulated leukotriene LTB4 at trough drug level, was reduced in all VIA-2291 groups (P<0.0001) in a dose-dependent fashion, with approximately 80% inhibition in >90% of patients in the 100-mg group. A significant reduction of urine leukotriene LTE4 was obtained in all dose groups. No serious adverse events were considered related to study drug. A subset of 93 patients who had undergone a 64-slice coronary CT examination at baseline continued on study medication for a total of 24 weeks and underwent a repeat scan. Five of these patients withdrew or were noncompliant and 28 had nonevaluable scans. Among the 60 remaining patients, new coronary plaques were observed in 5 of 18 (27.8%) placebo-treated patients and in 2 of 42 (4.8%) VIA-2291-treated patients (P=0.01). A reduction in noncalcified plaque volume at 24 weeks versus placebo was observed in VIA-2291-treated groups in the 34 of these 60 patients in whom this end point was analyzable (P<0.01). CONCLUSIONS: VIA-2291 reduces leukotriene production at 12 weeks after an acute coronary syndrome. Preliminary data from the CT substudy suggest that such a reduction in leukotriene production may influence atherosclerosis; however, this requires confirmation in a larger study. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00358826.

Dynamic imaging of T cell-dendritic cell interactions in lymph nodes.

T cell immune responses begin within organized lymphoid tissues. The pace, topology, and outcomes of the cellular interactions that underlie these responses have, so far, been inferred from static imaging of sectioned tissue or from studies of cultured cells. Here we report dynamic visualization of antigen-specific T cells interacting with dendritic cells within intact explanted lymph nodes. We observed immunological synapse formation and prolonged interactions between these two cell types, followed by the activation, dissociation, and rapid migration of T cells away from the antigenic stimulus. This high-resolution spatiotemporal analysis provides insight into the nature of cell interactions critical to early immune responses within lymphoid structures.

Aerobic exercise in the rehabilitation of cancer patients after high dose chemotherapy and autologous peripheral stem cell transplantation.

BACKGROUND: Fatigue and loss of physical performance are frequent problems of cancer patients. In a pilot study, the authors evaluated the feasibility and effects of aerobic training in the rehabilitation of cancer patients after completing high dose chemotherapy. METHODS: Sixteen patients participated in a specially designed rehabilitation program for 6 weeks. The patients entered the program, which consisted of walking on a treadmill, shortly after completing treatment. Sixteen patients who did not train served as controls. Physical performance (maximum speed on the treadmill test), cardiac function, and hemoglobin concentration were compared at the time of discharge from the hospital and 7 weeks later. At the second examination, fatigue and limitations in daily activities due to impaired endurance were assessed during personal interviews. RESULTS: At the time of discharge from the hospital, maximum physical performance (training group: 6.2 +/- 1.1 km/hour; controls: 6.2 +/- 1.3 km/hour) and hemoglobin concentration (training group: 10.1 +/- 1.4 g/dL; controls: 10.1 +/- 1.2 g/dL) were similar for both groups. After 7 weeks, improvement in maximum physical performance (training group: 8.3 +/- 1.6 km/hour; controls 7.5 +/- 1.3 km/hour) and hemoglobin concentration (training group: 13 +/- 1 g/dL controls: 12 +/- 1.4 g/dL) were significantly higher for the training group (P < 0.05). By the second examination, no patient in the training group but 4 controls (25%) reported fatigue and limitations in daily activities due to low physical performance. CONCLUSIONS: Aerobic exercise improves the physical performance of cancer patients recovering from high dose chemotherapy. To reduce fatigue, this group of patients should be counseled to increase physical activity rather than rest after treatment.

Different types of blockers of the intermediate-conductance outwardly rectifying chloride channel in epithelia.

Epithelial chloride channels can be blocked by various inhibitors, which show considerable differences in their molecular structure. In the present patch-clamp study, we compared different blockers of one type of epithelial Cl- channel with respect to their inhibitory potency. We applied the blockers to excised inside-out-or outside-out-oriented membrane patches of cultured HT29 colon carcinoma and respiratory epithelial cells (REC) containing the outwardly rectifying intermediate-conductance (ICOR) chloride channel. Four types of inhibitory compounds were tested: stilbene disulphonate derivatives, indanyloxyacetic acid, amidine, and arylaminobenzoates. The concentrations for half-maximal inhibition (IC50) for the different channel blockers were (mumol/l): 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulphonic acid 100; 4,4'-diisothiocyanato-stilbene-2,2'-disulphonic acid 80; indanyloxyacetic acid 9; 4,4'-dinitrostilbene-2,2'-disulphonic acid 8; amidine 8 and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) 0.9. All compounds, when applied to the cytosolic side of the channel, induced a flicker-type block of the ICOR Cl- channel at lower concentrations and a complete channel inhibition at higher concentrations. The inhibitory potency of NPPB was much higher when it was added to the external surface of the channel in outside-out-oriented membrane patches. At 1 mumol/l the inhibition was complete. All blocker effects were fully reversible. The probe with the highest affinity (NPPB) and a closely related compound 5-nitro-2-(3-phenylethylamino)-benzoate (NPEB) were used to construct macromolecular probes by linking these blockers to aminopolyethyleneglycol (PEG) or amino-ethyl-O-dextran (5 kDa).2+ These macromolecular NPPB and NPEB derivatives inhibited the ICOR Cl- channels only from the outside but had no effect on the cytosolic side.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of epithelial chloride channels by cytosol.

Chloride channels that have an intermediate conductance and are outwardly rectifying were studied by the patch-clamp technique in cell-excised membrane patches from respiratory epithelial cells in primary culture (REC) of normal and cystic fibrosis tissue, HT29 and T84 human colon carcinoma cells and placenta trophoblast cells (PTC). Chloride channels were immediately activated by the exposure of the cytosolic side of the patch to a Ringer-type solution, which lacked cytosolic components normally inhibiting chloride channels in the "on" cell configuration. Tentatively, we labelled the cytosolic component (or components) responsible for this inhibition cytosolic inhibitor (CI). The presence of CI in cytosol derived from HT29 cells was shown by assaying crude cytosol extracts from these cells on Cl- channels from HT29 cells (n = 2) and REC from normal subjects and cystic fibrosis patients (n = 4). In order to examine CI further, PTC were used as a source of cytosol. The cytosol of PTC inhibited HT29 Cl- channels in a dose-dependent manner with a half-maximal inhibition observed at a 1:6 dilution (n = 11) of the native cytosol. CI from PTC was heat-stable (10 min at 100 degrees C, n = 8). When cytosol extract was partitioned into a chloroform phase, Cl- channel inhibition was shown for the lipophilic extract (n = 12) as well as for the aqueous phase (n = 10). The inhibitory potency of the lipid extract was slightly larger than that of the aqueous phase. Several separation procedures were used to determine the molecular size of CI. When CI was filtered through 30-kDa filters at 6000 rpm for 45 min, inhibitory potency was observed in the filtrate and the retained fraction (n = 3). The same was observed with 10-kDa filters (n = 6). When CI was dialysed through a 12-kDa membrane, inhibitory capacity was recovered from the dialysate. Similarly, gel filtration indicated that CI was less than 5 kDa (n = 13) and probably less than 1.5 kDa (n = 11), but greater than 700 kDa (n = 9). CI was exposed to bead-coupled hydrolysing enzymes (trypsin, non-specific protease, lipase, alpha-amylase, nucleotidase), but none of the enzymes used destroyed the inhibitory potency of CI. These data indicate that CI is present in HT29 as well as in PTC. It inhibits reversibly intermediate-conductance outwardly rectifying Cl- channels in REC, HT29, and PTC.(ABSTRACT TRUNCATED AT 400 WORDS)