The use of immunomodulators in early rheumatoid arthritis

Thiazolo[3,2-a]benzimidazoles: synthetic strategies, chemical transformations and biological activities

The present review covers the recent synthetic strategies and chemical transformations of thiazolo[3,2-a]benzimidazoles and it also presents the highlights of the biological activities of these compounds.

Facile synthesis and in-vitro antitumor activity of some pyrazolo[3,4-b]pyridines and pyrazolo[1,5-a]pyrimidines linked to a thiazolo[3,2-a]benzimidazole moiety

The key precursor E-3-(N,N-dimethylamino)-1-(3-methylthiazolo[3,2-a]benzimidazol-2-yl)prop-2-en-1-one 4 was synthesized in good yield using Gold's reagent. The reaction of enaminone 4 with 5-amino-3-aryl-1-phenylpyrazoles 5a, b in refluxing acetic acid in the presence of sulphuric acid, yielded pyrazolo[3,4-b]pyridines 7a, b. Similarly, pyrazolo[1,5-a]pyrimidines 10a, b and 14a-f were prepared by reaction of enaminone 4 with 5-amino-1H-pyrazoles 8a, b and 12a-f, respectively. The structure of pyrazolo[1,5-a]pyrimidine 10b was determined by X-ray diffraction. The synthesized compounds were tested for their in-vitro antitumor activity against the colon cancer cell line CaCo-2; their cytotoxicity against the normal fibroblast cell line BHK was explored as well. Some of the tested compounds exhibited cell growth inhibitory activity. The significant antitumor activity of compound 14f against the CaCo-2 cell line (IC(50 )= 0.5 microg/mL) was coupled with a lower toxicity against BHK (IC(50 )= 2.3 microg/mL).

Suppressive effects of bee venom on the immune responses in collagen-induced arthritis in rats

The effect of bee venom (BVA) on the development of type II collagen (CII)-induced arthritis (CIA) in rats has been studied. Male rats were immunized with an emulsion of 200 microg of CII and complete Freund's adjuvant (CFA). The rats were then given intraperitoneally (i.p.) injection of a suspension of BVA or saline during the experiment. The effect of BVA on cellular responses to CII was examined. In the control rats, the onset of arthritis was observed at the 24th day after the CII-immunization, and the severity of CIA was developed gradually. As compared with rats treated with saline, BVA i.p. injected at doses of more than 20 microl/100g mouse once a day for 14 days inhibited the ability of inguinal lymph node cells to produce T cell cytokines interleukin-1beta, -2, -6, tumor necrosis factor-alpha and interferon-gamma when the cells were obtained from rats 24 days after immunization and cultured in vitro with CII. When rats were injected i.p. with sheep red blood cells, hemagglutination titers in BVA-treated and control rats did not differ significantly when low doses of BVA was given to rats. However, i.p. injection of BVA at doses of more than 10 microl/100g/day suppressed antibody production. Pretreatment of rats with BVA could inhibit the development of collagen arthritis even when 10-20 microl/100g/day of the BVA were used for pretreatment. Interestingly, higher doses than 10 microlBVA/100g mouse were much effective for arthritis incidence. Treatment of rats with BVA prevented the development of collagen arthritis in a dose-dependent manner. Doses of BVA (15 and 20 microl/100g) resulted in decreased incidence of arthritis. In conclusion, therapeutic i.p injection with BVA improved the clinical course of the disease and the immune response to CII.

Effect ofButhus martensiKarsch on Aromatase Activity and Cytokine-Inducded NOS and NO Production in Osteoblasts and Leukaemic Cell Line FLG 29.1

Among the different scorpion species, Buthus martensi Karsch, a widely distributed scorpion species in Asia especially in Korea, has received a lot of attention. Indeed, over the past decade, more than 70 different peptides, toxins, or homologues have been isolated. It may prove a valuable resource for identifying potential anti-inflammatory and analgesic drugs. The recent observation has suggested that the aromatase is a possible local modulator of bone remodeling in osteoarthritis and osteoporosis. In the present study, therefore, the effect of Buthus martensi Karsch (BMK) extract, traditional immunosuppressive Korean aqua-acupuncture water, on the bone function of human osteoblastic cells was studied. To provide insights into the effect of BMK on aromatase activity in bone-derived cells, we examined the human leukaemic cell line FLG 29.1, which is induced to differentiate toward the osteoclastic phenotype by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and transforming growth factor (TGF)-beta1, and the primary first-passage osteoblastic cells (hOB). Gene expression of the aromatase was not affected by Buthus martensi Karsch in FLG 29.1 and hOB cells. However, enzyme activity was stimulated in a time-dependent fashion by 10.0 microg/ml BMK and by either 1-50 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 hr exposure. On the other hand, BMK strongly inhibited interleukin-1beta (IL-1beta)- and tumor necrosis factor (TNF)alpha-induced Nitricoxide (NO) synthase expression with little effect on constitutive NO synthase expression. BMK extracts (10 microg/ml) inhibited cytokine-induced iNOS and nNOS expression. BMK (10 microg/ml) did not affect the ecNOS expression, indicating the extracts are not working on the constitutive NOS expression. BMK strongly inhibited the cytokine-induced NO production (p < 0.01). BMK also showed significant inhibition on NO production in both induced by TNF-alpha+IL-1beta. NO donors, sodium nitroprusside, and NONOate dose-dependently elevated alkaline phosphatase activity. These results suggest that NO directly facilitates osteoblastic differentiation. This result also suggests that BMK is effective for bone resorptive action in bone cells.

Inhibitory effect of Buthus martensi Karsch extracts on interleukin-1β-induced expression of nitric oxide (NO) synthase and production of NO in human chondrocytes and LPS-induced NO and prostaglandin E2 production in mouse peritoneal macrophages

We examined the effect of Buthus martensi Karsch (BMK) extract on IL-1beta-induced production of nitrogen oxide (NO) in primary human osteoarthritis (OA) chondrocytes. The cells were treated with BMK (10 microg/ml) and IL-1beta (2 ng/ml) for different periods, and inducible nitric oxide synthase (iNOS) mRNA and protein expression were determined by real-time quantitative reverse transcriptase-polymerase chain reaction and Western blotting, respectively. The cytotoxicity of BMK on human OA chondrocytes was very low (IC50 > 250 microg/ml) as measured by the XTT assay method. Production of NO was determined as nitrite in culture supernatant. Human chondrocytes cotreated with BMK produced significantly less NO compared with chondrocytes stimulated with IL-1beta alone. Activation and translocation of and NF-(kappa)B DNA binding activity were determined by Western blotting and specific enzyme-linked immunosorbent assay. The inhibition of NO production correlated with the suppression of induction and expression of nuclear factor-kappaB (NF-(kappa)B) and activation protein-1 (AP-1)-dependent gene. BMK inhibited the activation and translocation of NF-(kappa)B to the nucleus, indicating that BMK inhibits the IL-1beta-induced production of NO in human chondrocytes by interfering with the activation of NF-(kappa)B through a novel mechanism. In addition, BMK reduced prostaglandin E2 (PGE2) production in mouse peritoneal macrophages stimulated with lipopolysaccharide, whereas no influence on the activity of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) or cyclooxygenase-1 (COX-1) was observed. Our data, therefore, suggest that BMK may be a therapeutically effective inhibitor of IL-1beta-induced inflammatory effects that are dependent on NF-(kappa)B activation in human OA chondrocytes. The results indicate that BMK exerts anti-inflammatory effects related to the inhibition of neutrophil functions and of NO and PGE2 production, which could be due to a decreased expression of iNOS and COX-2 through the transcription factors NF-(kappa)B and AP-1.

Effect of bee venom on aromatase expression and activity in leukaemic FLG 29.1 and primary osteoblastic cells

The effect of bee venom aqua-acupuncture (BVA) (api-toxin), a traditional immunosuppressive Korean aqua-acupuncture, on the bone function in human osteoblastic cells was studied. To provide insights into the effect of BVA on aromatase activity in bone-derived cells, we examined the human leukaemic cell line FLG 29.1, which is induced to differentiate toward the osteoclastic phenotype by TPA and TGF-beta1, and the primary first-passage osteoblastic cells (hOB). Southern blot of RT-PCR products with a 32P-labeled cDNA probe for the human aromatase demonstrated that FLG 29.1 and hOB cells express aromatase mRNA. Gene expression and enzyme activity were stimulated in a time-dependent fashion by 5.0 microl/ml BV and by either 1-50 nM TPA or 0.01-0.5 ng/ml TGF-beta1, with maximal responses after 2-3 h exposure. After 24 h incubation of the cells in the absence of these stimuli the aromatase mRNA and the protein were barely detectable. These findings demonstrate that cells of the osteoclastic lineage synthesize aromatase in vitro by the local cytokine of TGF-beta1 and BVA. These can offer an explanation for the lack of development of osteoarthritis in BVA-treated patients.

Sirolimus: continuing the evolution of transplant immunosuppression

OBJECTIVE

To review the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and economic issues associated with sirolimus, the most recent immunosuppressive agent approved for kidney transplantation.

DATA SOURCES

A MEDLINE search (1966-June 2000) was completed to identify primary and review articles. In addition, abstracts from recent meetings on transplantation were reviewed for information and research on sirolimus.

STUDY SELECTION AND DATA EXTRACTION

Blinded, randomized, controlled studies were the goal, but, as with most newly approved immunosuppressive agents, a significant amount of information on sirolimus is not available in this optimal form. All articles were assessed and all pertinent information was incorporated in this review.

DATA SYNTHESIS

Sirolimus is structurally related to the immunosuppressive agent tacrolimus, and retains a pharmacokinetic and drug interaction profile similar to that of the calcineurin inhibitors, cyclosporine and tacrolimus. However, the novel mechanism of action of sirolimus differs significantly from these agents, as does its adverse effect profile. The most significant adverse reaction is hyperlipidemia. Clinical experience with sirolimus has allowed transplant centers to expand its use into other areas of transplantation as well as certain autoimmune disorders.

CONCLUSIONS

The definitive role of sirolimus will continue to be determined; however, sirolimus offers an excellent addition to the transplant immunosuppression armamentarium.

Suppressive effects of Tripterygium wilfordii Hook f., a traditional Chinese medicine, on collagen arthritis in mice

The effect of chloroform extract of Tripterygium wilfordii Hook f. (TWH extract), a traditional immunosuppressive Chinese herb, on type II collagen (C II)-induced arthritis (CIA) in DBA/1J mice was studied. In the first set of experiments, we examined the effect of TWH extract on cellular immune responses to C II. As compared with mice treated with saline, TWH extract administered orally at doses of more than 400 microg kg(-1) once a day for 14 days inhibited the ability of inguinal lymph node cells to produce T cell cytokines interleukin-2 and interferon-gamma when the cells were obtained from mice 21 days after immunization and cultured in vitro with C II. Treatment with TWH extract also inhibited production of macrophage cytokines interleukin-1beta and tumor necrosis factor-alpha in response to in vitro stimulation of lymph node cells with C II. In the second part of the experiment, we evaluated the influence of TWH extract on the incidence and development of arthritis in murine CIA. Mice were immunized twice at a 3-week interval with bovine C II, with TWH extract being given orally once a day for 14 days with four different regimens. A 14-day course of TWH extract treatment at a daily dose of 400 microg kg(-1), which began on the day of the first C II immunization, suppressed the development of arthritis, as well as antibody production and delayed-type hypersensitivity to C II. Treatment with TWH extract, which started on the same day as the booster immunization, also resulted in inhibition of development of arthritis and of immune responses to C II. On the other hand, therapeutic administration with TWH extract did not affect the clinical course of the disease and the immune response to C II.

Effects of antirheumatic agents on cytokines

A review of the literature concerning the effects of traditional antirheumatic drugs on cytokines and the cytokine and anticytokine approaches already used in the therapy of rheumatoid arthritis (RA) is presented. Many antirheumatic drugs are capable of cytokine modulation in vitro. Corticosteroids inhibit the transcription of a broad spectrum of genes including those encoding monocyte, T cell-derived cytokines and several hemopoietic growth factors, whereas drugs such as cyclosporin A and D-penicillamine interfere with T cell activation more specifically by suppressing interleukin 2 (IL-2) production. The in vivo effects of drug therapy on cytokines in RA patients are less well established. Gold compounds reduce circulating IL-6 levels and the expression of monocyte-derived cytokines, such as IL-1, tumor necrosis factor (TNF), and IL-6, in the rheumatoid synovium. Decreases in circulating IL-6, soluble IL-2 (sIL-2R), and TNF receptors and in synovial fluid IL-1 levels have been reported with methotrexate. Reductions in circulating IL-6 and sIL-2R concentrations have also been observed with cyclosporin and corticosteroids, whereas azathioprine reduces IL-6 but not sIL-2R. Studies on sulfasalazine are conflicting and the in vivo effects of D-penicillamine and antimalarials have not been studied yet. Interferon gamma therapy is not effective in RA but may prove a useful antifibrotic for systemic sclerosis. Colony stimulating factors improve the granulocytopenia associated with Felty's syndrome or drug toxicities but can induce arthritis flares and should be reserved to treat infectious complications. Promising results are being obtained with selective antagonism of TNF and IL-1 in RA, and combinations of anticytokine strategies with traditional antirheumatic drugs have been already envisaged. These should preferably be based in a broader knowledge of the effects of antirheumatic agents on the cytokine network.