Drug treatment for rheumatoid arthritis

Total knee arthroplasty for rheumatoid arthritis

Abstract Total knee arthroplasty is a proven technique for the management of deformity and unremitting pain in the rheumatoid arthritic knee. Many important considerations must be taken into account in order to maximize the results of total knee replacement in this challenging patient population.

Cemented total hip arthroplasty in rheumatoid arthritis. A systematic review of the literature

BACKGROUND

Cemented total hip arthroplasty (THA) in rheumatoid arthritis (RA) is allegedly associated with increased rates of infection, dislocation and aseptic loosening of cup and stem.

METHOD

Systematic review of the literature on clinical and radiological results of cemented THA in RA.

RESULTS

Twenty-one case series and eight reports on four implant registries were included. The quality of most studies was judged to be poor. The reported rates of infection and dislocation in the case series were conflicting with a risk of bias due to under-registration. The registries proved unsuitable for providing reliable data on the incidence of these two complications. Increased rates of aseptic loosening were reported in 10 out of 20 case series on the cup and in six out of 19 on the stem. Nearly all of these were based on series implanted before 1980. None of the registries reported a significantly increased risk of aseptic loosening of cup or stem.

CONCLUSIONS

Considering the relatively frequent reports of increased infection rates in combination with the potential under-registration of complications, RA patients have to be considered to have a mild increased risk of postoperative infection. Case series and registries cannot answer the question of whether RA is a risk factor for dislocation as multivariate analysis is required. Increased rates of cup and stem failure due to aseptic loosening in RA patients are found in older but not in more recent studies.

Dexamethasone promotes osteoclastogenesis by inhibiting osteoprotegerin through multiple levels

Increased bone fragility attributed to osteopenia is a serious side effect of glucocorticoid treatment. Glucocorticoid-induced bone loss is caused primarily by hypofunction and apoptosis of osteoblasts, and secondarily by accelerated bone resorption. To explore the mechanism whereby dexamethasone (Dex) stimulates osteoclastogenesis in the coculture system, we analyzed the effect of Dex on the expression of both mouse osteoprotegerin (OPG) and receptor activator of NF-kappaB ligand (RANKL). Dex reduced OPG transcripts and OPG protein secretion by the ST2 osteoblastic cells. Since mainly the c-Jun homodimer maintains the steady-state transcription of the OPG gene, we examined the effect of Dex on c-Jun signaling in ST2 cells. Western blotting disclosed that Dex decreased the amount of phospho-c-Jun protein (p-c-Jun) and, correspondingly, the amount of the phosphorylated p46 isoform of Jun N-terminal kinase (JNK). The amount of phospho-SEK1 also decreased after Dex treatment, while the amounts of phospho-ERK and p38 remained constant. Among mitogen-activated protein (MAP) kinase inhibitors, the JNK inhibitor mimicked the inhibitory effect of Dex on OPG promoter activity. On the other hand, Dex treatment per se showed a nominal increase of RANKL gene expression. A part of Dex-mediated OPG gene suppression was achieved by the suppression of beta-catenin signaling. We speculate therefore that the bone resorptive action of Dex is mediated mainly by the inhibition of OPG by transrepressing the OPG gene through the AP-1 site, with a reduction (mediated mainly by the decrease in the p46 isoform of JNK) in the proportion of p-c-Jun in a JNK-dependent manner.

Developments in the rat adjuvant arthritis model and its use in therapeutic evaluation of novel non-invasive treatment by SOD in Transfersomes

The aim of this study was firstly to refine a rat model of arthritis, the adjuvant arthritis (AA) model, by studying the time course of the disease, introducing new evaluation methods such as haematological and biochemical parameters in order to identify the main stages of the disease. An optimisation of treatment schedule and evaluation criteria was developed. This refinement provided novel non-invasive anti-inflammatory treatment of the AA with SOD by using mixed lipid vesicles specially developed for transdermal delivery, Transfersomes (Tfs), this being the second major aim. The time course of AA includes a first stage: 1 day after the disease induction, the induced paw volume more than doubled and the paw circumference increased by approx. 50%. Two weeks later, another stage occurred where the disease shifted from the local arthritis form towards polyarthritis: an additional increase of volume and circumference of the induced and non-induced paws, occurred. The animals also started to loose weight around day 14 after the disease induction. Radiographic observable lesions increased correspondingly. Treatment of animals, started at day 1 after induction, by epicutaneous application of SOD-Tfs showed that 1 mg SOD/kg body weight is more efficient than 0.66 mg SOD /kg body weight. As a positive control, SOD liposomes intravenously injected were used for comparison and confirmed the biological efficiency of epicutaneously applied SOD in Tfs. SOD solution and empty Tfs epicutaneously applied exerted no effect. In addition, epicutaneous application of SOD-Tfs used prophylactically was able to suppress the induced rat paw oedema. Radiographic images showed less joint lesions in SOD-Tfs treated animals in comparison with control and placebo treated rats. It was shown for the first time that SOD incorporated into Tfs and applied onto a skin area not necessarily close to the inflamed tissue is able to promote non-invasive treatment of induced arthritis.

Dexamethasone enhances osteoclast formation synergistically with transforming growth factor-beta by stimulating the priming of osteoclast progenitors for differentiation into osteoclasts

Long-term administration of glucocorticoids (GCs) causes osteoporosis with a rapid and severe bone loss and with a slow and prolonged bone disruption. Although the involvement of GCs in osteoblastic proliferation and differentiation has been studied extensively, their direct action on osteoclasts is still controversial and not conclusive. In this study, we investigated the direct participation of GCs in osteoclastogenesis. Dexamethasone (Dex) at <10(-8) M stimulated, but at >10(-7) M depressed, receptor activator of NF-kappaB ligand (RANKL)-induced osteoclast formation synergistically with transforming growth factor-beta. The stimulatory action of Dex was restricted to the early phase of osteoclast differentiation and enhanced the priming of osteoclast progenitors (bone marrow-derived monocytes/macrophages) toward differentiation into cells of the osteoclast lineage. The osteoclast differentiation depending on RANKL requires the activation of NF-kappaB and AP-1, and the DNA binding of these transcription factors to their respective consensus cis-elements was enhanced by Dex, consistent with the stimulation of osteoclastogenesis. However, Dex did not affect the RANKL-induced signaling pathways such as the activation of IkappaB kinase followed by NF-kappaB nuclear translocation or the activation of JNK. On the other hand, Dex significantly decreased the endogenous production of interferon-beta, and this cytokine depressed the RANKL-elicited DNA binding of NF-kappaB and AP-1, as well as osteoclast formation. Thus, the down-regulation of inhibitory cytokines such as interferon-beta by Dex may allow the osteoclast progenitors to be freed from the suppression of osteoclastogenesis, resulting in an increased number of osteoclasts, as is observed in the early phase of GC-induced osteoporosis.

Antiarthritic activity of an orally active C5a receptor antagonist against antigen-induced monarticular arthritis in the rat

OBJECTIVE

To determine if the new, orally active C5a receptor antagonist, the cyclic peptide AcF-[OPdChaWR], reduces the severity of pathology in a rat model of immune-mediated monarticular arthritis.

METHODS

Arthritis was induced in the right knee of previously sensitized rats by the intraarticular injection of methylated bovine serum albumin. Rats were examined for either 14 days or 28 days, or for 49 days following a second antigen challenge at 28 days. The C5a antagonist (1 or 3 mg/kg/day) and/or ibuprofen (30 mg/kg/day) were administered orally on a daily basis either before or after arthritis induction.

RESULTS

Rats receiving AcF-[OPdChaWR] had significant reductions in right knee swelling, gait disturbance, lavaged joint cell numbers, and right knee histopathology, as well as in serum levels of tumor necrosis factor alpha (TNFalpha) and intraarticular levels of interleukin-6 and TNFalpha on day 14. In the 14- and 28-day studies, ibuprofen resulted in a similar reduction in gait abnormalities and intraarticular inflammatory cells compared with the C5a antagonist, but was less effective in reducing knee swelling over the course of the study and had no effect on knee histopathology. Combination therapy with AcF-[OPdChaWR] and ibuprofen resulted in no greater efficacy than with the C5a antagonist alone. Rats injected twice with the antigen in the 49-day study displayed the most severe histopathology and this, as well as knee swelling and gait abnormalities, was significantly reduced by repeated treatment with the C5a antagonist.

CONCLUSION

An agent that inhibits the action of C5a in this model significantly reduced joint pathology, while ibuprofen was not effective. C5a antagonists could therefore have broader therapeutic benefits than nonsteroidal antiinflammatory drugs as antiarthritic agents for rheumatoid arthritis.

2-Chloroadenosine but not adenosine induces apoptosis in rheumatoid fibroblasts independently of cell surface adenosine receptor signalling

1. The apoptotic effect of adenosine and its analogues was studied in fibroblast-like synoviocytes derived from rheumatoid arthritis patients (RA-FLSs). Evoked cell death was quantitatively examined by assessing DNA fragmentation using an enzyme-liked immunosorbent assay and by measuring phosphatidylserine exposure through flow cytometric analysis of annexin V binding. 2. Exposing cells for 24 h to 2-chloroadenosine (2-CADO), a nonspecific, adenosine deaminase (ADA)-resistant, adenosine receptor (AdoR) agonist, induced DNA fragmentation, and thus apoptosis, in RA-FLSs at concentrations > or =50 microM. By contrast, incubation with adenosine for up to 72 h did not evoke DNA fragmentation, even in the presence of ADA inhibitor coformycin and nucleoside transporter inhibitor nitrobenzylmercaptopurin (NBMPR). Transcription of all four AdoR isoforms was detected in RA-FLSs; nevertheless selective AdoR agonists similarly failed to induce DNA fragmentation. 3. DNA fragmentation evoked by 2-CADO was inhibited by NBMPR and by 5'-iodotubercidin, an adenosine kinase inhibitor, but not by xanthine amine congener, an A(1) and A(2) receptor antagonist, or by selective AdoR antagonists. 4. The nonspecific caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone abolished the apoptotic effect of 2-CADO. 5. These results suggest that 2-CADO induces apoptosis in RA-FLSs independently of AdoR-mediated signalling. Instead, 2-CADO, but not adenosine, is taken up into RA-FLSs via human equilibrative nucleoside transporter-1, where it is phosphorylated by adenosine kinase. The resultant phospho-2-CADO induces DNA fragmentation by activating a caspase pathway.