A novel anti-rheumatic drug suppresses tumor necrosis factor-alpha and augments interleukin-10 in adjuvant arthritic rats.

Tumor necrosis factor-alpha (TNF-alpha) plays an important role in the pathology of rheumatoid arthritis. When N-[1-(4-¿[4-(pyrimidin-2-yl)piperazin-1-yl]methyl¿phenyl)cycloprop yl] acetamide (Y-39041) (3-30 mg/kg) was orally administered to rats with established arthritis from day 15 to day 20, hindpaw volume was significantly reduced. This inhibitory activity of Y-39041 was kept up after administration was stopped. On day 17 Y-39041 suppressed lipopolysaccharide-induced TNF-alpha and interleukin-6 production in serum at doses of 3-30 mg/kg, and augmented interleukin-10 production at doses of 10 and 30 mg/kg. The finding that Y-39041 suppresses TNF-alpha and interleukin-6 production and augments interleukin-10 production could be beneficial in the therapy of chronic inflammatory diseases.

Enhancement of host defense by Y-25510, (+-)-3-[4-(2-dimethylamino-1-methylethoxy)phenyl]-1H-pyrazolo[3,4 -b] pyridine-1-acetic acid, a novel synthetic compound. A comparison with recombinant human granulocyte colony-stimulating factor in 5-fluorouracil-treated mice.

The effect of a novel synthetic compound, Y-25510, (+-)-3-[4-(2-dimethylamino-1-methylethoxy)phenyl]-1H-pyrazolo[3,4 -b] pyridine-1-acetic acid, on recovery from long-lasting leukopenia induced by 5-fluorouracil was compared with that of recombinant human granulocyte colony-stimulating factor (rhG-CSF). When mice were administered i.p. with 5-FU (200 mg/kg) on days 0 and 7, intravenous administration of Y-25510 (100 and 1000 micrograms/kg) prevented the decrease in the peripheral leukocyte and neutrophil number and accelerated the recovery from leukopenia. Subcutaneous administration of rhG-CSF (50 micrograms/kg) did not prevent leukopenia but accelerated the recovery from leukopenia. In particular, peripheral neutrophil number increased over a normal level. The administration of Y-25510 (10, 100 and 1000 micrograms/kg) restored the decrease in the number of bone marrow cells, spleen cells, lymphocytes, neutrophils and monocytes. The administration of rhG-CSF (50 micrograms/kg) restored the decrease in the number of bone marrow cells, spleen cells, and neutrophils but not that of lymphocytes and monocytes. In fractions of bone marrow cells on day 21, the administration of Y-25510 (1000 micrograms/kg) showed a tendency of restoring the decrease in neutrophil number. In conclusion, the administration of Y-25510 prevented leukopenia and accelerated the recovery from leukopenia in the 5-FU-treated mice. It is suggested that the mechanism of the restorative action of Y-25510 is different from that of rhG-CSF. In a number of immature bone marrow cells Y-25510 has a potent stimulatory effect on the recovery from the decrease in number of hematopoietic cells, keeping a balance in number of each blood cell.

Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanism (IV): Potentiating effects on the function of peritoneal or spleen macrophages.

L-Cysteine ethylester hydrochloride (ethylcysteine; 30 mg/kg, p.o.) increased the number of la-positive cells (antigen presenting cells) in spleen adherent cells (SAC) and that of Lyt 1.2-positive cells (helper T cells), but not that of Lyt 2.2-positive cells (suppressor T cells) of C57BL/6 mice immunized with sheep red blood cells. The production of hemolytic plaque forming cells (HPFC) in spleens of syngeneic recipient mice was enhanced by the transfer of SAC or spleen lymphocytes of the donor mice pretreated with ethylcysteine. This drug augmented phagocytosis of yeast particles by peritoneal macrophages of ICR mice at concentrations of 1-100 microM. In ex vivo experiments, this drug (30 mg/kg, p.o.) augmented the phagocytosis of yeast particles by mouse macrophages and showed a tendency to increase the macrophage number in the peritoneal cavity. Ethylcysteine (30 mg/kg, p.o.) significantly accelerated the decrease of viable E. coli number in the liver of normal mice 2 and 48 hr after challenge. Furthermore, this drug at the same dose restored the suppression of the decrease of E. coli number in the blood and liver of mice treated with cyclophosphamide (200 mg/kg, i.p.). These results suggest that ethylcysteine augments the functions of macrophages in vitro and ex vivo, and these enhancing effects may lead to the enhancement of host resistance to infections in compromised hosts.

[Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanisms (II): Restorative effects on the suppression of antibody production].

The production of hemolytic plaque forming cells (HPFC) in the spleen of BALB/c mice immunized with sheep red blood cells was significantly inhibited by carrageenan treatment (0.3 mg/kg, i.p.; on days -3 and -1). Cysteine ethylester hydrochloride (ethylcysteine) restored the inhibition of the HPFC production by carrageenan treatment in a dose-dependent manner (10-100 mg/kg, p.o.). Ia positive cells (antigen-presenting cells) increased in the spleen adherent cells (SAC) obtained from immunized mice, whereas they decreased in the SAC obtained from carrageenan-treated mice. An increase of Ia positive cells occurred in the SAC of carrageenan-treated mice given ethylcysteine. Ethylcysteine (10-100 mg/kg, p.o.; on days -2 and -1) prevented both the suppression of the HPFC production and the decrease of the number of thymus lymphocytes and peripheral leukocytes induced by cyclophosphamide treatment (30 mg/kg, i.p.; on days -1 and 0). Lyt 1.2 positive cells (helper T cells) decreased in the spleen T cells of cyclophosphamide-treated mice, but increased in the spleen T cells from cyclophosphamide-treated mice give ethylcysteine. On the other hand, Thy 1.2 negative cells (B cells) did not increase in the spleen cells of cyclophosphamide-treated mice with or without ethylcysteine. These results suggest that ethylcysteine restores the immune response in immunosuppressed mice through the functions of macrophages and/or helper T cells.

[Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanisms (III): Potentiating effects on phagocytosis and nitroblue tetrazolium (NBT) reduction by leukocytes of mice and guinea pigs].

ICR mice were treated orally with cysteine ethylester hydrochloride (ethylcysteine, 10 and 100 mg/kg) immediately before the intraperitoneal injection of yeast particles. This agent significantly potentiated phagocytosis of yeast particles by peritoneal polymorphonuclear leukocytes in mice obtained 2 hr after the yeast injection, and the treatment with this agent (3 and 30 mg/kg, p.o.) 4 hr before the injection of yeast potentiated phagocytosis of yeast particles by mouse peritoneal leukocytes. This agent (30 mg/kg, p.o.) restored the suppression of phagocytosis of mouse leukocytes by the intraperitoneal administration of cyclophosphamide (30 mg/kg, i.p.) 24 hr before the yeast injection. This agent (10-100 mg/kg, p.o.) had no effect on the decrease of peripheral leukocyte number in irradiated mice (560 rad), but restored the suppression of phagocytosis, nitroblue tetrazolium (NBT) reduction and stimulated NBT reduction by the addition of lipopolysaccharide. Furthermore, this agent (3-30 mg/kg, p.o.) potentiated phagocytosis, NBT reduction and stimulated NBT reduction of peripheral leukocytes obtained from guinea pigs 2 and 6 hr after ethylcysteine treatment. It is suggested that ethylcysteine potentiates phagocytosis and NBT reduction of leukocytes in animals, and it restores phagocytosis and NBT reduction inhibited by the treatment with cyclophosphamide or X-ray irradiation. It may be possible that this stimulating effect of ethylcysteine could be at least in part involved in the stimulation of nonspecific resistance to infection in the compromised host.

[Effect of cysteine ethylester hydrochloride (Cystanin) on host defense mechanism].

Cysteine ethylester (10 approximately 100 mg/kg, p.o.) augmented the production of hemolytic plaque-forming cells (HPFC) to sheep red blood cells and lipopolysaccharide in the spleen of mice. It showed no effect, however, on the HPFC production to trinitrophenylated polyvinylpyrrolidone; and it had no activity as a polyclonal B cell activator like lipopolysaccharide. Cysteine ethylester at a concentration of 3 microM or more potentiated the phagocytosis of yeast by the peritoneal polymorphonuclear leukocytes of rats. This activity was less potent than that of levamisole and D-penicillamine. It also potentiated the reduction of nitroblue tetrazolium (NBT) by blood leukocytes prepared from guinea pigs and a human being. This activity was more potent than that of levamisole and D-penicillamine. Furthermore, cysteine ethylester at doses showing an immunopotentiating activity protected irradiated mice from death by spontaneous infection. These findings suggest that this drug may have a capacity to potentiate the host defense mechanisms.