Immunosuppressants-ligands as neuroprotectants

Effects of edaravone on human neutrophil function

BACKGROUND

Neutrophils play a crucial role in the antibacterial host defence system. Edaravone is used in critically ill patients who are often immuno-compromised secondary to concomitant disease or immunosuppressive therapy. The aim of the current study was to assess the effect of edaravone, a novel free-radical scavenger, on several aspects of human neutrophil function using an in vitro system.

METHODS

Chemotaxis, phagocytosis, reactive oxygen species (ROS) production by neutrophil (cellular) and xanthine-xanthine oxidase (acellular) systems, and intracellular calcium ion levels ([Ca(2 +) ]i) were measured in the absence and in the presence (at a clinically relevant concentration, and 0.1-fold, and 10-fold this concentration) of edaravone.

RESULTS

The clinically relevant concentration of edaravone did not inhibit chemotxais, phagocytosis, or superoxide production of neutrophils. Even at its ordinary clinical plasma concentration, the drug inhibited hydrogen peroxide (H(2)O(2)) and hydroxyl radical (OH*) generation in the cellular (neutrophil) as well as in the cell-free (xanthine-xanthine oxidase) system (P < 0.05). Edaravone did not affect elevation of [Ca(2 +) ]i in neutrophils stimulated by a chemotactic factor.

CONCLUSIONS

These findings suggest that edaravone quenched H(2)O(2), and OH* generated rather than impaired the ability of neutrophils to produce the ROS. However, further studies using in vivo systems are required to elucidate the effects of edaravone on neutrophil function in clinical settings.

Nonmyeloablative allogeneic bone marrow transplantation for treatment of myelodysplastic syndrome complicated by recent intracerebral hemorrhage

A patient with intracerebral hemorrhage is considered ineligible for hematopoietic stem cell transplantation (HSCT). We report a 49-year-old woman with myelodysplastic syndrome (MDS) complicated by refractoriness to platelet transfusion and intracerebral hemorrhage, who underwent allogeneic bone marrow transplantation from an HLA-identical unrelated male donor. Nine days before the scheduled transplantation, she developed dysarthria and right hemiparesis; computed tomography (CT) of the brain disclosed an acute hematoma in the left parietal lobe exceeding 3 cm in diameter. She underwent conditioning with reduced-intensity, including fludarabine (30 mg/m2/day on days -8 to -3), busulfan (4 mg/kg/day on days -6 and -5), and total body irradiation (4 Gy on day -2). Two weeks after transplantation, dysarthria and right hemiparesis began to resolve, and CT showed spontaneous resolution of the hematoma. Simultaneously, engraftment was confirmed. Thus, recent stroke may be not an absolute contraindication for HSCT.

Inhibitory effects of cyclosporin A on calcium mobilization-dependent interleukin-8 expression and invasive potential of human glioblastoma U251MG cells

Interleukin (IL)-8 produced from glioblastoma is suggested to contribute to its own proliferation and progression. Since various external stimuli have been shown to increase intracellular Ca(2+) in glioma cells, we investigated Ca(2+) mobilization-dependent IL-8 expression and effect of cyclosporin A (CsA), an inhibitor of calcineurin (Cn), on the expression and invasive potential of human glioblastoma U251MG cells. Combined treatment with Ca(2+)-ionophore and phorbol-myristate-acetate (A23187/PMA) increased IL-8 mRNA and protein levels. This increase was suppressed by CsA and by another Cn inhibitor FK506. Luciferase reporter gene assay and electrophoretic mobility shift assay revealed that activation of p65-containing nuclear factor-kappaB was essential for A23187/PMA-dependent activation of IL-8 promoter. CsA suppressed the promoter activity by attenuating IkappaB-alpha degradation. U251MG cells expressed IL-8 receptors CXCR-1 and -2, and Matrigel invasion assay revealed that CsA attenuated A23187/PMA-dependent stimulation of invasive potential, probably by inhibiting IL-8 production. In addition, IL-8-dependent proliferation was also suppressed by CsA. Taken together, these results demonstrate the novel inhibitory effects of CsA on glioblastoma cell functions, suggesting CsA as a potential therapeutic adjuvant for glioma treatment.