Tumor necrosis factor (TNF) inhibitor therapy for rheumatoid arthritis

Intraarticular Injection of Infliximab-Loaded Thermosensitive Hydrogel Alleviates Pain and Protects Cartilage in Rheumatoid Arthritis

Purpose

Pain and cartilage destruction caused by rheumatoid arthritis (RA) are major challenges during clinical treatment. Traditional systemic administration not only has obvious side effects but also provides limited relief for local symptoms in major joints. Local delivery of therapeutics for RA treatment is a potential strategy but is limited by rapid intraarticular release.

Materials and Methods

In this study, we prepared a thermoresponsive injectable hydrogel by mixing pluronic F127 (F127) and hyaluronic acid (HA) with poly (γ-glutamic acid) (PGA) incorporating infliximab (IFX), a new generation monoclonal antibody drug. We investigated the biocompatibility of the hydrogel and its IFX release profile. In vivo, we studied the clinical manifestations (articular skin temperature and joint diameter), detected cytokines in the synovial fluid and cartilage, performed behavioral studies on pain relief, and evaluated the cartilage protection effect.

Results

A thermoresponsive hydrogel was successfully prepared by mixing F127, HA, and PGA with injectable properties. The F127-HA-PGA hydrogel had a porous structure with interconnected pores. The infliximab-loaded thermosensitive hydrogel exhibited good biocompatibility and biodegradability and sustained release properties. Intraarticular injection of the IFX-loaded F127-HA-PGA hydrogel could alleviate the expression of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-17 (IL-17), in the synovial fluid and cartilage as well as relieve pain and inhibit cartilage destruction in RA.

Conclusion

The double effect on pain relief and cartilage protection indicated the significant potential of the IFX-loaded injectable hydrogel for RA treatment in major joint lesions.

Specific activation of pro-Infliximab enhances selectivity and safety of rheumatoid arthritis therapy

During rheumatoid arthritis (RA) treatment, long-term injection of antitumor necrosis factor α antibodies (anti-TNFα Abs) may induce on-target toxicities, including severe infections (tuberculosis [TB] or septic arthritis) and malignancy. Here, we used an immunoglobulin G1 (IgG1) hinge as an Ab lock to cover the TNFα-binding site of Infliximab by linking it with matrix metalloproteinase (MMP) -2/9 substrate to generate pro-Infliximab that can be specifically activated in the RA region to enhance the selectivity and safety of treatment. The Ab lock significantly inhibits the TNFα binding and reduces the anti-idiotypic (anti-Id) Ab binding to pro-Infliximab by 395-fold, 108-fold compared with Infliximab, respectively, and MMP-2/9 can completely restore the TNFα neutralizing ability of pro-Infliximab to block TNFα downstream signaling. Pro-Infliximab was only selectively activated in the disease site (mouse paws) and presented similar pharmacokinetics (PKs) and bio-distribution to Infliximab. Furthermore, pro-Infliximab not only provided equivalent therapeutic efficacy to Infliximab but also maintained mouse immunity against Listeria infection in the RA mouse model, leading to a significantly higher survival rate (71%) than that of the Infliximab treatment group (0%). The high-selectivity pro-Infliximab maintains host immunity and keeps the original therapeutic efficiency, providing a novel strategy for RA therapy.

During treatment of rheumatoid arthritis, systemic administration of anti-TNFα antibodies may induce on-target toxicities, limiting their application. The incorporation of IgG1 hinge as an antibody lock generates a pro-Infliximab whose activation is specific to the disease region, enabling safer RA therapy.

Bone morphogenetic protein-2 exhibits therapeutic benefits for osteonecrosis of the femoral head through induction of cartilage and bone cells

Osteonecrosis of the femoral head is an orthopedic disease caused by femoral head damage or insufficient blood supply, which leads to the death of bone cells and bone marrow. Osteonecrosis of the femoral head leads to changes in the structure of the femoral head, femoral head collapse and joint dysfunction. Bone morphogenetic protein-2 (BMP-2) exhibits beneficial effects on bone formation, repair and angiogenesis at the femoral head. In the present study, the therapeutic effects of recombinant human BMP-2 containing an Fc fragment (rBMP-2/Fc) were investigated on a steroid induced mouse model of osteonecrosis of the femoral head. Bone cell viability was used to determine the in vitro effects of rBMP-2/Fc. The therapeutic efficacies of rBMP-2/Fc on mice with osteonecrosis of the femoral head were evaluated using clinical arthritis scores. The expression levels of inflammatory factors in the mice were analyzed by reverse transcription-quantitative polymerase chain reaction. Histological analysis was used to evaluate the effects of rBMP-2/Fc on the femoral head. The results revealed that rBMP-2/Fc treatment significantly increased the IL-6, IL-10, vascular endothelial growth factor and macrophage colony-stimulating factor expression levels in synovial cells compared with the control group (P<0.01). Furthermore, it was observed that rBMP-2/Fc significantly improved the viability and growth of synovial cells (P<0.01) through the nuclear factor (NF)-κB signaling pathway. Treatment with rBMP-2/Fc significantly decreased receptor activator of NF-κB ligand expression levels. Furthermore, in vivo experiments demonstrated that rBMP-2/Fc treatment markedly relieved the arthralgia and damage caused by osteonecrosis of the femoral head. In conclusion, rBMP-2/Fc treatment may be beneficial for articular cartilage repair by the upregulation of angiogenesis factors through the down regulation of the NF-κB signaling pathway in mice with osteonecrosis of the femoral head. This preclinical data suggests that rBMP-2/Fc may be a promising novel agent for treatment of osteonecrosis of the femoral head.

Platelet-rich plasma has beneficial effects in mice with osteonecrosis of the femoral head by promoting angiogenesis

Platelet-rich plasma (PRP) is autologous and multifunctional. Platelet concentrate from blood contains highly concentrated platelets and various types of cells, including growth factors. PRP promotes the recovery of cell proliferation and differentiation. Osteonecrosis of the femoral head is a disease caused by femoral head damage or an insufficient blood supply, which leads to the death of bone cells and abnormal bone marrow composition. The subsequent repair of bone cells may result in changes to the structure of femoral head, femoral head collapse and joint dysfunction. PRP may promote the repair of injured articular cartilage in patients with joint diseases through the removal of harmful inflammatory factors. In the present study, the therapeutic effects and primary mechanism of PRP action were investigated using a glucocorticoid-induced femoral head osteonecrosis mouse model. Dexamethasone (DEX) and phosphate-buffered saline were used as controls. The therapeutic efficacy of PRP to treat osteonecrosis in murine femoral heads was evaluated by assessing clinical arthritis scores. The present study indicated that mice with osteonecrosis of the femoral head treated with PRP exhibited downregulated expression of interleukin (IL)-17A, IL-1β, tumor necrosis factor-α, receptor activator of nuclear factor κ-B ligand, IL-6 and interferon-γ in the inflammatory tissue. In addition, the levels of hepatocyte growth factor, intercellular adhesion molecule-1, osteopontin, platelet-derived endothelial cell growth factor, vascular endothelial growth factor, platelet-derived growth factor, insulin-like growth factor-1 and transforming growth factor-β were increased following treatment with PRP. Joint tissue histological staining demonstrated that PRP alleviated osteonecrosis of the femoral head and reduced humoral and cellular immune responses that promoted beneficial effects on the histological parameters. Furthermore, the concentration of glucocorticoids were significantly decreased in the serum of PRP-treated mice with osteonecrosis compared with the DEX group (P<0.01). Notably, PRP promoted beneficial effects in mice with osteonecrosis of the femoral head by stimulating angiogenesis. Therefore, the present study indicated that treatment with PRP promotes beneficial effects by preventing joint inflammation, cartilage destruction and bone damage, and stimulating the repair of joint tissue in mice with osteonecrosis of the femoral head. These preclinical data suggest that PRP may be developed as a novel method of treating osteonecrosis of the femoral head.

Platelet-rich plasma shows beneficial effects for patients with knee osteoarthritis by suppressing inflammatory factors

Knee osteoarthritis is a degenerative disease that may develop due ageing, obesity, strain, congenital abnormal joints, joint deformity or trauma. It is caused by many factors, such as degradation of articular cartilage injury, joint edge and subchondral bone hyperplasia of reactivity. Platelet-rich plasma (PRP) is an autologous blood sample that contains highly concentrated platelets and multiple cell growth factors. PRP promotes synovial cell proliferation and differentiation and may recover cartilage morphology. In the present study, the clinical efficacy of PRP was investigated in patients with knee osteoarthritis aged between 18 and 30 years in a phase-III clinical study. Following an 8-week baseline, patients with knee osteoarthritis were randomized into once-weekly, double-blind treatment with PRP (2-14 ml) or placebo groups. The results indicated that patients with osteoarthritis treated with PRP had modulated plasma concentrations of inflammatory factors and pro-angiogenic factors compared with the placebo group. Treatment responses were assessed by median percent reduction in inflammatory and pro-angiogenic factors and these improved with PRP treatment compared with the placebo. Clinical data indicated that PRP alleviated knee osteoarthritis and reduced humoral and cellular immune responses that led to beneficial effects on histological parameters. Inflammation was significantly alleviated in patients receiving PRP compared with the placebo group. The most common treatment-emergent adverse events in the presence of PRP were hypertension and proteinuria. In conclusion, treatment with PRP for patients with knee osteoarthritis presented beneficial effects in alleviating joint inflammation, cartilage destruction and bone damage, and repairing joint tissue. These results suggested that PRP may be a potential therapeutic agent for knee osteoarthritis.

Platelet-rich plasma exhibits beneficial effects for rheumatoid arthritis mice by suppressing inflammatory factors

Platelet-rich plasma (PRP) is a multifunctional blood product containing highly concentrated platelets, and various cell growth factors which promote cell proliferation and differentiation. PRP exhibited benefits in injurious articular cartilage repair and the removal of inflammatory factors in clinical studies. Rheumatoid arthritis (RA) is an autoimmune disease manifesting primarily as inflammatory arthritis, which is associated with notable morbidity in humans. In the present study, the therapeutic effects and primary mechanism of PRP on a type II collagen‑induced arthritis (CIA) mouse model was investigated. Inflammatory factors interleukin (IL)‑6, IL‑8, IL‑17, IL‑1β, tumor necrosis factor (TNF)‑α and interferon (IFN)‑γ were analyzed in PRP and PBS‑treated groups. Vascular endothelial growth factor (VEGF), platelet‑derived growth factor (PDGF), insulin‑like growth factor (IGF)‑1 and transforming growth factor (TGF)‑β expression in peripheral whole blood was additionally analyzed. The therapeutic efficacy of PRP for RA mice was evaluated using clinical arthritis scores. The results of the present study demonstrated that treatment with PRP alleviated arthritis, and reduced humoral and cellular immune responses, leading to beneficial effects on histological parameters as observed using joint tissue histological staining. CIA mice treated with PRP exhibited downregulated expression of IL‑6, IL‑8, IL‑17A, IL‑1β, TNF‑α, receptor activator for nuclear factor‑κB and IFN‑γ in inflammatory tissue. In addition, VEGF, PDGF, IGF‑1 and TGF‑β expression in peripheral whole blood was increased following treatment with PRP. The serum concentration of anti‑collagen antibody was decreased in PRP‑treated CIA mice. In conclusion, CIA mice treated with PRP exhibited beneficial effects, including decreased joint inflammation, cartilage destruction and bone damage, and increased repair of joint tissue. The results of the present study suggested that PRP may be an effective therapeutic agent for RA.

Mandibular movements in older people with rheumatoid arthritis

OBJECTIVE

The aim of this study was to compare the mandibular movements in older people with and without temporomandibular disorder (TMD) associated with rheumatoid arthritis (RA).

STUDY DESIGN

Thirty partially or completely edentulous older adults (65.33 ± 4.7 years) were assigned to 2 groups: (1) with RA and TMD and (2) without RA and TMD. Chewing movements of the jaws during mastication of the test material (Optocal) and the range of mandibular movements were evaluated by using the JT-3-D kinesiographic device before and after new removable prosthesis insertion. Multiple comparisons were made with analysis of variance (ANOVA) and the Tukey-Kramer test.

RESULTS

Comparisons between the 2 groups before and after new prosthesis insertion revealed that the RA and TMD group had reduced opening angles (P < .05) during chewing. After insertion of new prostheses, both groups showed increased opening and closing angles during chewing (P < .05). The mandibular range of motion results showed that patients with RA and TMD exhibited lower aperture and laterality movements (P < .05) compared with controls before and after new prosthesis insertion. However, there was an increase in aperture, lefty laterality, and protrusion values after new prosthesis insertion in both groups.

CONCLUSIONS

TMD associated with RA may impair mandibular movements. Well-fitted prostheses may improve mandibular movements in older adults, especially those with RA.

Predictive gene signature of response to the anti-TweakR mAb PDL192 in patient-derived breast cancer xenografts

Purpose

(1) To determine TweakR expression in human breast cancers (BC), (2) evaluate the antitumor effect of the anti-TweakR antibody PDL192, used alone or after chemotherapy-induced complete remission (CR), on patient-derived BC xenografts (PDX) and (3) define predictive markers of response.

Experimental Design

TweakR expression was analyzed by IHC on patients and PDXs BC samples. In vivo antitumor effect of PDL192 was evaluated on eight TweakR-positive BC PDXs alone or after complete remission induced by a combination of doxorubicin and cyclophosphamide. Using both responding and resistant PDX tumors after PDL192 administration, RT-QPCR were performed on a wide list of selected candidate genes to identify predictive markers of response.

Results

TweakR protein was expressed in about half of human BC samples. In vivo PDL192 treatment had significantly anti-tumor activity in 4 of 8 TweakR-positive BC PDXs, but no correlation between the expression level of the Tweak receptor and response to therapy was observed. PDL192 also significantly delayed tumor relapse after CR. Finally, an 8 gene signature was defined from sensitive and resistant PDXs.

Conclusions

PDL192 was highly efficient in some BC PDXs. We found 8 genes that were differentially expressed in responding and resistant tumors and could constitute a gene expression signature which would need to be extended to other xenograft models for confirmation. These data confirm the therapeutic potential of TweakR targeting in BC and the possibility of prospectively selecting patients who might benefit from therapy.

Retrospective cohort study of anti-tumor necrosis factor agent use in a veteran population

Introduction. Anti-tumor necrosis factor (TNF) agents are effective for several immunologic conditions (rheumatoid arthritis (RA), Crohn’s disease (CD), and psoriasis). The purpose of this study was to evaluate the efficacy and safety of anti-TNF agents via chart review.

Methods. Single-site, retrospective cohort study that evaluated the efficacy and safety of anti-TNF agents in veterans initiated between 2010 and 2011. Primary aim evaluated response at 12 months post-index date. Secondary aims evaluated initial response prior to 12 months post-index date and infection events.

Results. A majority of patients were prescribed anti-TNF agents for CD (27%) and RA (24%). Patients were initiated on etanercept (41%), adalimumab (40%), and infliximab (18%) between 2010 and 2011. No differences in patient demographics were reported. Response rates were high overall. Sixty-five percent of etanercept patients, 82% of adalimumab patients, and 59% of infliximab patients were either partial or full responders, respectively. Approximately 16%, 11%, and 12% of etanercept, adalimumab, and infliximab were non-responders, respectively. Infections between the groups were non-significant. Etanercept and adalimumab patients had higher but non-significant odds of being a responder relative to infliximab.

Conclusions. Most patients initiated with anti-TNF agent were responders at 12 months follow-up for all indications in a veteran population.

ADAMTS-12: a multifaced metalloproteinase in arthritis and inflammation

ADAMTS-12 is a member of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family of proteases, which were known to play important roles in various biological and pathological processes, such as development, angiogenesis, inflammation, cancer, arthritis, and atherosclerosis. In this review, we briefly summarize the structural organization of ADAMTS-12; concentrate on the emerging role of ADAMTS-12 in several pathophysiological conditions, including intervertebral disc degeneration, tumorigenesis and angioinhibitory effects, pediatric stroke, gonad differentiation, trophoblast invasion, and genetic linkage to schizophrenia and asthma, with special focus on its role in arthritis and inflammation; and end with the perspective research of ADAMTS-12 and its potential as a promising diagnostic and therapeutic target in various kinds of diseases and conditions.

Immunomodulation in human and experimental arthritis: including vitamin D, helminths and heat-shock proteins

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that is mainly directed to the joints, affecting the synovial membrane, the cartilage and also the bone. This disease affects 1% to 2% of the world population and is associated with significant morbidity and increased mortality. RA experimental models have allowed a great deal of information to be translated to the corresponding human disease. This review summarizes some of the most relevant findings targeting immunomodulation in arthritis. Some general guidelines to choose an adequate experimental model and also our experience with arthritis are supplied.

A novel IKKα inhibitor, noraristeromycin, blocks the chronic inflammation associated with collagen-induced arthritis in mice

OBJECTIVES

To evaluate the therapeutic efficacy of a novel inhibitor for IκB kinase alpha (IKKα), noraristeromycin (NAM), for murine experimental model of rheumatoid arthritis, collagen- induced arthritis (CIA).

METHODS

NAM has been chemically synthesized as reported earlier. CIA was induced in DBA/1JNCrlj mice by intradermal inoculation of bovine type II collagen (col II) together with Freund Complete Adjuvant. Following the Day 21 booster injection of col II with Freund Incomplete Adjuvant, the animals were monitored for the development of arthritis and clinically evaluated. NAM was administered orally at different doses prior to induction (prophylactic protocol) or after the emergence of definitive arthritis (therapeutic protocol).

RESULTS

Here we demonstrate the experimental evidence that oral administration of NAM could completely prevent the occurrence of experimental arthritis in CIA mouse model at 0.3 mg/kg with ED50 value of approximately 0.1 mg/kg twice daily. Moreover, twice daily oral therapeutic dosage of 1 mg/kg of NAM significantly inhibited the paw swelling and disease progression even after the occurrence of experimental CIA. In addition, NAM exhibited an excellent pharmacokinetics in mice and oral administration of NAM could suppress the production of TNFα elicited by lipopolysaccharide (LPS) in a dose-dependent manner.

CONCLUSIONS

These results indicated that IKKα inhibition is an effective novel therapy for the treatment of chronic inflammatory processes such as those associated with RA and other related conditions.

Endemic fungal infections in inflammatory bowel disease associated with anti-TNF antibody therapy

Patients with inflammatory bowel disease are susceptible to complications from pharmacologic treatment of their disease. Tumor necrosis factor (TNF)-α inhibitors are being used increasingly in the treatment of inflammatory bowel disease and can be associated with adverse events, including common infections, and rarely the development of serious life-threatening opportunistic infections. TNF-α inhibitors have the ability to prevent an effective patient granulomatous response, and this may be associated with an increased risk of developing mycobacterial and certain fungal infections, including histoplasmosis, blastomycosis, and coccidioidomycosis, endemic in several parts of the United States. The concern for invasive fungal infection was realized during clinical trials and further demonstrated after the marketing of TNF-α inhibitors. Because of this awareness, the Food and Drug Administration developed an adverse event-reporting system to capture cases of infections associated with the use of TNF-α inhibitors. These opportunistic fungi have a great degree of regional variability, and it has been very difficult to quantify the incidence of infection in patients treated with TNF-α inhibitors. Currently, there are no formal guidelines regarding the use of TNF-α inhibitors and these fungal infections. Considering that gastroenterologists have embraced the use TNF-α inhibitors as a valuable armamentarium in the treatment of inflammatory bowel disease, they must be aware of therapy-related infectious complications, including appropriate diagnostic, therapeutic, and preventive strategies. In this article, we explore the association of these fungal entities in relation to the TNF-α inhibitor therapy by considering information provided in the gastroenterology, infectious diseases, rheumatology, and transplant literature. Finally, we provide some recommendations on diagnosis and treatment.

DBM1285 suppresses tumor necrosis factor alpha production by blocking p38 mitogen-activated protein kinase/mitogen-activated protein kinase-activated protein kinase 2 signaling pathway

Tumor necrosis factor alpha (TNF-alpha) is a major inflammatory cytokine that plays an important role in the development of various inflammatory diseases. TNF-alpha has been considered as a potential therapeutic target for the treatment of chronic inflammatory diseases, including rheumatoid arthritis and inflammatory bowel disease. In this study, we report that cyclopropyl-{4-[4-(4-fluorophenyl)-2-piperidin-4-yl-thiazol-5-yl]pyrimidin-2-yl}amine (DBM1285) is a novel inhibitor of TNF-alpha production. DBM1285 concentration-dependently inhibited lipopolysaccharide (LPS)-induced TNF-alpha secretion in various cells of macrophage/monocyte lineage, including mouse bone marrow macrophages, THP-1 cells, and RAW 264.7 cells. However, LPS-induced mRNA expression of TNF-alpha was not affected by DBM1285 in these cells. Further studies demonstrated that the inhibitory effect of DBM1285 on TNF-alpha production might be mediated by post-transcriptional regulation through the modulation of the p38 mitogen-activated protein kinase (MAPK)/MAPK-activated protein kinase 2 (MK2) signaling pathway. We also confirmed that DBM1285 directly inhibits p38 MAPK enzymatic activity. In vivo administration of DBM1285 inhibited LPS-induced increase in the plasma level of TNF-alpha in mice. Whole-blood in vivo target inhibition assay also revealed that DBM1285 attenuates p38 MAPK activity after oral administration in mice. Moreover, DBM1285 suppressed zymosan-induced inflammation and adjuvant-induced arthritis in murine models. Collectively, these results suggest that DBM1285 inhibits TNF-alpha production, at least in part, by blocking the p38 MAPK/MK2 pathway. Furthermore, in vivo results suggest that DBM1285 might be a possible therapeutic candidate for the treatment of TNF-alpha-related chronic inflammatory diseases.

Description of the efficacy and safety of three new biologics in the treatment of rheumatoid arthritis

English articles on abatacept, golimumab, and tocilizumab in rheumatoid arthritis published between 2002 and 2009 were reviewed systematically. All randomized clinical trials, open-label extensions, meta-analyses, and reviews were examined. There were thirteen articles on abatacept, four on golimumab, and seven on tocilizumab. All three drugs were effective in methotrexate-naïve, methotrexate-incomplete responders, and tumor-necrosis-factor-failure rheumatoid arthritis patients. Of the three, only abatacept has been tested in a head-to-head trial with infliximab, in which it was found to be equivalent to infliximab. Golimumab resulted in a more modest improvement than the others in methotrexate-naïve patients, although no direct comparisons among the three drugs were possible or appropriate. Descriptive analysis of adverse events showed that patients receiving abatacept, golimumab, and tocilizumab were subject to more adverse events than controls overall, as expected. In the abatacept studies, a few cases of tuberculosis, more cardiovascular events and gastrointestinal bleedings and more basal cell carcinoma were seen. Golimumab was associated with more skin rashes and pneumonia, while tocilizumab was associated with increased lipids, more liver-function abnormalities, and neutropenia. These new medications are useful additions to the rheumatologic armamentarium and represent greater convenience (golimumab) or different mechanisms of action (abatacept and tocilizumab) than tumor-necrosis-factor inhibitors for treating rheumatoid arthritis. As expected, some adverse events occur when using these drugs and patients need to be watched carefully.

Dichloroacetate alleviates development of collagen II-induced arthritis in female DBA/1 mice

INTRODUCTION

Dichloroacetate (DCA) has been in clinical use for the treatment of lactacidosis and inherited mitochondrial disorders. It has potent anti-tumor effects both in vivo and in vitro, facilitating apoptosis and inhibiting proliferation. The pro-apoptotic and anti-proliferative properties of DCA prompted us to investigate the effects of this compound in arthritis.

METHODS

In the present study, we used DCA to treat murine collagen type II (CII)-induced arthritis (CIA), an experimental model of rheumatoid arthritis. DBA/1 mice were treated with DCA given in drinking water.

RESULTS

Mice treated with DCA displayed much slower onset of CIA and significantly lower severity (P < 0.0001) and much lower frequency (36% in DCA group vs. 86% in control group) of arthritis. Also, cartilage and joint destruction was significantly decreased following DCA treatment (P = 0.005). Moreover, DCA prevented arthritis-induced cortical bone mineral loss. This clinical picture was also reflected by lower levels of anti-CII antibodies in DCA-treated versus control mice, indicating that DCA affected the humoral response. In contrast, DCA had no effect on T cell- or granulocyte-mediated responses. The beneficial effect of DCA was present in female DBA/1 mice only. This was due in part to the effect of estrogen, since ovariectomized mice did not benefit from DCA treatment to the same extent as sham-operated controls (day 30, 38.7% of ovarectomized mice had arthritis vs. only 3.4% in sham-operated group).

CONCLUSION

Our results indicate that DCA delays the onset and alleviates the progression of CIA in an estrogen-dependent manner.

Tyrosine kinases as targets for the treatment of rheumatoid arthritis

As critical regulators of numerous cell signaling pathways, tyrosine kinases are implicated in the pathogenesis of several diseases, including rheumatoid arthritis (RA). In the absence of disease, synoviocytes produce factors that provide nutrition and lubrication for the surrounding cartilage tissue; few cellular infiltrates are seen in the synovium. In RA, however, macrophages, neutrophils, T cells and B cells infiltrate the synovium and produce cytokines, chemokines and degradative enzymes that promote inflammation and joint destruction. In addition, the synovial lining expands owing to the proliferation of synoviocytes and infiltration of inflammatory cells to form a pannus, which invades the surrounding bone and cartilage. Many of these cell responses are regulated by tyrosine kinases that operate in specific signaling pathways, and inhibition of a number of these kinases might be expected to provide benefit in RA.