Inhibition of type II collagen-induced arthritis in rats by triptolide.

The effects of purified triptolide, a diterpenoid triepoxide compound derived from the Chinese traditional anti-rheumatic medicinal plant extract, Tripterygium wilfordii Hook f (TWHf), were determined in type II collagen-induced arthritis (CIA) in rats. Lewis rats were immunized with bovine type II collagen and treated with purified triptolide 0.1 mg/kg/day or control (vehicle for triptolide) by daily gavage feedings for 28 days. Triptolide was well-tolerated with no evidence of toxicity. Treatment with triptolide resulted in significant delay in time to onset of arthritis (P = 0.039), as well as significantly decreased arthritis incidence (P = 0.024), clinical arthritis severity score (P < 0.0001), histopathological arthritis severity score (P < 0.0001), and in vivo cell-mediated immunity to collagen (P = 0.0004). Triptolide appeared to be a potent immunomodulatory inhibitor of CIA in rats and this may account for the previously observed anti-rheumatic properties of crude extracts of TWHf, although more extensive studies will be needed to confirm these effects.

A pilot study of zileuton, a novel selective 5-lipoxygenase inhibitor, in patients with systemic lupus erythematosus.

OBJECTIVE: This is a pilot study of zileuton, a selective 5-lipoxygenase inhibitor in systemic lupus erythematosus (SLE). METHODS: Forty patients with SLE received zileuton 600 mg qid or placebo in an 8 week, randomized prospective, double blind trial. Disease activity was manifested largely by constitutional, articular, and skin manifestations with no evidence of active renal, cardiac, or neurologic involvement. Concomitant administration of nonsteroidal antiinflammatories, corticosteroids, or antimalarials was not permitted. Disease activity was determined at baseline and at Days 15 and 57 by assessment of arthritis severity, the Systemic Lupus Activity Measure (SLAM), investigator and patient global ratings, hematologic indices, and serologic measures including autoantibody titers, complement levels, and interleukin 2 receptors (IL-2R). Total body sulfidopeptide leukotriene synthesis was measured by urinary leukotriene E4 (LTE4) concentrations. RESULTS: Overall SLAM (the primary measure of efficacy in this study) was significantly improved with zileuton compared with placebo (-2.1 +/- 1.3, compared with an increase of 2.3 +/- 1.3 with placebo by Day 57, p = 0.048). Changes in individual SLAM subscores, arthritis severity, global ratings, and IL-2R levels compared with baseline did not achieve statistical significance, but were generally decreased from baseline with zileuton (indicating trends towards improvement) and increased from baseline with placebo (indicating trends towards clinical worsening). Urine LTE4 levels at Day 57 had increased from baseline in the placebo group (indicating worsening) and decreased in the zileuton group (indicating improvement). CONCLUSION: Selective 5-lipoxygenase inhibition may be beneficial in mild SLE.

Population pharmacokinetics of zileution, a selective 5-lipoxygenase inhibitor, in patients with rheumatoid arthritis.

The pharmacokinetics of zileuton, a novel selective 5-lipoxygenase inhibitor, were studied in 37 patients with rheumatoid arthritis after administration of 200 mg, 400 mg, and 600 mg, zileuton for 4 weeks. Patients had 6-h pharmacokinetic evaluation of zileuton on day 14. Plasma zileuton concentrations were quantitated using HPLC. Zileuton pharmacokinetic parameters were estimated using standard noncompartmental methods. A population analysis of zileuton pharmacokinetics was also performed with the NONMEM computer program. The pharmacokinetics of zileuton in patients with rheumatoid arthritis were similar to those previously estimated in normal healthy humans. The peak concentrations and the areas under the curves during the dosing interval were dose proportional. The noncompartmental means of the CL/f, terminal-phase half-life, and V/f of zileuton were approximately 545 ml min-1, 1.4 h, and 64.3 1, respectively. The estimate of population typical values of the CL/f for a 70-kg person (540 ml min-1) and V/f for a 70-kg person (64.8 1) from the NONMEM analysis were in agreement with the noncompartmental estimates. Differences in body weight, but not age or gender, helped explain some of the variability in the pharmacokinetics of zileuton in patients. Therefore, there is no pharmacokinetic basis for alteration of the zileuton dose size or the dosing schedule in patients with rheumatoid arthritis.

Combined treatment with terbutaline and aminophylline inhibits experimental amyloidosis in mice.

OBJECTIVE: To investigate the effects of drugs known to elevate adenosine 3':5'-cyclic monophosphate (cAMP) on experimental amyloidosis. METHODS: A beta 2-agonist, terbutaline, and a phosphodiesterase inhibitor, aminophylline, were administered in combination in a mouse model of amyloidosis induced by inflammatory stimulation with silver nitrate. Amyloidosis was quantitated by radioimmunoassay for splenic amyloid A (AA) protein. RESULTS: At the doses selected, aminophylline/terbutaline inhibited splenic amyloid deposition more potently than did colchicine, a known inhibitor of amyloidosis. CONCLUSION: Drugs known to elevate cAMP inhibit experimental mouse AA amyloidosis.

Suppression of renal disease and arthritis, and prolongation of survival in MRL-lpr mice treated with an extract of Tripterygium wilfordii Hook f.

OBJECTIVE: Treatment of MRL-lpr/lpr mice with Tripterygium wilfordii Hook f (TWHf) to evaluate its effects on mortality, renal disease, and arthritis. METHODS: Mice were fed water (group A, control), TWHf (group B), or first water and then TWHf (group C) from age 7 weeks until age 21 weeks. RESULTS: Arthritis and glomerulonephritis were decreased in groups B and C mice, and survival was increased in group B mice. CONCLUSION: TWHf decreases the mortality rate, and severity of glomerulonephritis and arthritis in MRL-lpr/lpr mice.

Defective lipopolysaccharide-induced production of both interleukin 1 alpha and interleukin 1 beta by A/J mouse macrophages is posttranscriptionally regulated.

Interleukin 1 (IL-1) production by A/J (A) and C57BL/6J (B6) mouse peritoneal macrophages stimulated with lipopolysaccharide (LPS) was determined. Strain A macrophages produced low levels of soluble IL-1 bioactivity compared with B6 macrophages. This defect was not reversed by indomethacin, interferon-gamma, phorbol myristate acetate, or calcium ionophore A23187. In contrast, cytosolic IL-1 bioactivity was similar in LPS-stimulated A and B6 macrophages. Western blotting revealed that A macrophage supernatants contained lower levels of both 17-kd IL-1 alpha and 17-kd IL-1 beta but similar levels of tumor necrosis factor alpha compared with B6 macrophages. Cytosolic levels of 31-kd pro-IL-1 alpha and also 31-kd pro-IL-1 beta were similar in A and B6 macrophages. Oligonucleotide probing indicated that A and B6 macrophages contained similar levels of IL-1 alpha and also IL-1 beta mRNA. These findings indicate that LPS-stimulated A macrophage culture supernatants contain low levels of both IL-1 alpha and IL-1 beta compared with B6 macrophages and that these defects in IL-1 production are posttranscriptionally regulated.

Inhibition of type II collagen induced arthritis in mice by an immunosuppressive extract of Tripterygium wilfordii Hook f.

The effects of Tripterygium wilfordii Hook f (TWHf), a Chinese herbal remedy, on type II collagen induced arthritis (CIA) in DBA/1LacJ mice were determined. Mice were divided into 4 groups receiving oral treatment for 63 days: Group A, sham feedings; Group B, TWHf (78 mg/day); Group C, TWHf (140 mg/day); Group D, TWHf (140 mg/day) starting 21 days after collagen immunization. Arthritis incidence was reduced and day of onset delayed in Groups B and C compared with A. Arthritic joint counts, arthritic severity scores, and anticollagen antibody titers were decreased in Groups B, C, and D compared with A. Histopathology revealed destructive arthritis only in Group A. Our results indicate that TWHf is a potent immunosuppressive inhibitor of CIA, even when treatment is begun 3 weeks after immunization.

Differential regulation of soluble interleukin 1 release and membrane expression by pharmacologic agents.

Membrane IL-1 (mIL-1) expression was compared with release of soluble IL-1 (sIL-1) by C3H/HeNCrl mouse peritoneal macrophages. Selective antagonists of protein kinase C (PKC) (H-7) and calmodulin (W-7) in combination inhibited LPS-induced mIL-1 and sIL-1 production, suggesting a role for these activation pathways in IL-1 induction. Low levels of A23187, when combined with OAG (a direct activator of PKC), stimulated mIL-1 expression in the absence of sIL-1 release. Induction of mIL-1 by LPS was inhibited by PGE2 and dibutyryl cAMP, but higher concentrations were required to inhibit mIL-1 expression compared with sIL-1 release. LTB4 alone did not induce mIL-1 or sIL-1 production. LTB4 did enhance LPS-induced mIL-1 expression but not sIL-1 release. These results indicate that mIL-1 expression and sIL-1 release are differentially regulated. Membrane IL-1 is induced by lower levels of certain stimuli and is less effectively inhibited than is sIL-1 release. This differential regulation is further evidence to support the existance of membrane IL-1.

Adult Still's disease in only one of identical twins.

This report describes the occurrence of adult Still's disease in only one of a pair of identical twins after 8 years of followup. This suggests that environmental factors may be important in the development of this rare syndrome in at least some patients.

Genetic regulation of lipopolysaccharide-induced interleukin 1 production by murine peritoneal macrophages.

The production of IL 1 by LPS-stimulated peritoneal macrophages from inbred mouse strains was studied. Macrophages from A/J (A) mice were deficient in IL 1 production, when compared with high IL 1-producing strains, including C57BL/6J (B). The difference between A and B macrophages was maintained over a wide LPS concentration range and throughout a 72-hr incubation period. Because of these differences, it was possible to investigate the mechanisms regulating IL 1 production by applying techniques of genetic analysis by using recombinant inbred (RI) strains derived from the A and B progenitors. A strain distribution pattern (SDP) of IL 1 production (low/high response) was obtained with the use of 15 AXB/BXA RI strains. This suggested the presence of a major gene locus controlling the production of IL 1 in response to LPS stimulation, with allelic differences presumably resulting in deficient or efficient IL 1 production. In addition, there appeared to be one or more other loci involved in determining the magnitude of the IL 1 response to LPS in the responder mice. The IL 1 response did not appear to be linked to the major histocompatibility complex, since B10.A mice (which share the same H-2a haplotype as A/J) were efficient IL 1 producers. There did not appear to be any correlation between the degree of IL 1 production and the magnitude of the peritoneal macrophage inflammatory response, or between IL 1 production and LPS responsiveness (as determined by splenocyte proliferation). SDP analysis also indicated that the IL 1 response was not linked to macrophage tumoricidal activity. A comparison of the SDP for IL 1 production with a library of SDP for other known genetic waits suggested linkage with at least four loci on chromosome 1.

Regulation of interleukin 1 production by mouse peritoneal macrophages. Effects of arachidonic acid metabolites, cyclic nucleotides, and interferons.

The effects of prostaglandin E2 (PGE2), cyclic nucleotides, leukotriene B4 (LTB4), and interferons on interleukin 1 (IL 1) production by lipopolysaccharide (LPS)-stimulated C3H/HeNCrl mouse peritoneal macrophages were studied. IL 1 production was inhibited by PGE2, the adenosine 3':5'-monophosphate analog dibutyryl cAMP, the cAMP agonist isoproterenol, and the phosphodiesterase inhibitor isobutylmethylxanthine. These agents were more inhibitory when added early in the latent phase of IL 1 synthesis following stimulation with LPS rather than just prior to release of IL 1 into the medium. Production of both the intracellular and extracellular forms of IL 1 was blocked by PGE2 and cAMP. Suppression of LPS-induced IL 1 production by PGE2 was prevented by leukocyte alpha-interferon. Moreover, alpha-interferon augmented LPS-induced IL 1 production but did not stimulate IL 1 production in the absence of LPS. Immune gamma-interferon markedly inhibited LPS-stimulated IL 1 production. The lipoxygenase inhibitor eicosa-5,8,11,14-tetraynoic acid suppressed, whereas 3-amino-1-(3-trifluoromethylphenyl)-2-pyrazoline augmented, LPS-induced IL 1 production. The opposing effects of these agents suggested that lipoxygenase metabolites do not act as inducers of IL 1 production. Purified LTB4 did not stimulate base-line or augment LPS-induced IL 1 production (both intracellular and extracellular forms). Moreover, calcium ionophore A23187 (a lipoxygenase activator) did not stimulate IL 1 production, alone or in combination with LTB4. Thus, net IL 1 production by macrophages may be regulated by a balance between the effects of PGE2, cAMP, alpha-interferon, and gamma-interferon, but not LTB4.

Prostaglandin E1 inhibition of experimental amyloidosis in CBA/J mice.

The antiinflammatory activity of systemically administered prostaglandin E1 (PGE1) was studied in experimental CBA/J mouse amyloidosis induced by chronic stimulation with silver nitrate. PGE1 lowered splenic deposition of amyloid A protein (AA) (p = 0.035). Serum amyloid A protein (SAA) levels were not suppressed by PGE1 in the acute phase, while decreased SAA levels appeared to be an integral part of the chronic inflammatory phase, with or without PGE1 treatment. Accelerated amyloid deposition induced by amyloid-enhancing factor (AEF) was not blocked by PGE1. This suggests that PGE1 inhibits amyloidosis in the predeposition phase, possibly by preventing formation of AEF or other deposition factors.

Effect of colchicine on experimental amyloidosis in two CBA/J mouse models. Chronic inflammatory stimulation and administration of amyloid-enhancing factor during acute inflammation.

To investigate the mechanism of action of colchicine in blocking amyloid deposition, two model systems of amyloidosis in CBA/J mice were studied. In experimental chronic inflammation, daily injection of silver nitrate (AgNO3) resulted in the deposition of 667 +/- 68 ng of amyloid A protein (AA)/mg of spleen after 25 days. Treatment with 10 micrograms of colchicine daily decreased AgNO3-induced AA deposition to 12 +/- 1 ng of AA/mg of spleen (p less than 0.001). Colchicine diminished the acute phase serum amyloid A protein (SAA) response after 24 hours. Over a 25-day period, SAA concentrations declined and approached baseline both in colchicine-treated and (unexpectedly) in control mice. This suggested that suppression of SAA levels was not the primary event inhibiting amyloid deposition. In a model of accelerated amyloid deposition, injection of preformed amyloid-enhancing factor along with AgNO3 induced the deposition of 974 +/- 46 ng of AA/mg of spleen 48 hours later. Colchicine only partially decreased amyloid-enhancing factor-induced amyloid deposition to 578 +/- 91 ng of AA/mg of spleen, while blunting the acute phase SAA response. These results suggest that colchicine inhibits amyloidosis in the predeposition phase, possibly by blocking formation of amyloid-enhancing factor.

Colchicine in acute inflammation: stimulation of production of interleukin-1 and modulation of the acute phase serum amyloid A protein response.

The effects of colchicine on the acute phase serum amyloid A (SAA) response were studied in CBA/J mice to determine whether these effects are mediated via inhibition of interleukin-1 (IL-1) production. Prolonged pretreatment (72 h) with colchicine blunted the SAA response to stimulation with silver nitrate (AgNO3), while brief pretreatment (12 h) unexpected augmented SAA production. In a macrophage model, colchicine stimulated baseline production of IL-1 (SAA inducer and lymphocyte activating factor activities) and augmented lipopolysaccharide (LPS) induced IL-1 production. This indicates that colchicine does not inhibit amyloidosis via direct effects on early inducers of the acute phase SAA response.

Serum amyloid A protein concentration in progressive systemic sclerosis (scleroderma).

Serum amyloid A protein (SAA) concentrations were determined in 62 patients with progressive systemic sclerosis (PSS). Forty-seven patients had normal or slightly elevated SAA levels (less than 1000 ng/ml = micrograms/l), while 15 patients had moderately to markedly elevated SAA levels, similar to those observed in active rheumatoid arthritis (RA) (greater than or equal to 1000 ng/ml = micrograms/l). Five patients with PSS had SAA levels corresponding to those observed in amyloidosis secondary to RA. High SAA was associated with more severe skin thickening and diminished cumulative survival at five years. The rarity of amyloidosis secondary to PSS is unlikely to be related to an intrinsic defect in SAA production.