Ulrich Feige

Activated T cells regulate bone loss and joint destruction in adjuvant arthritis through osteoprotegerin ligand.

Bone remodelling and bone loss are controlled by a balance between the tumour necrosis factor family molecule osteoprotegerin ligand (OPGL) and its decoy receptor osteoprotegerin (OPG). In addition, OPGL regulates lymph node organogenesis, lymphocyte development and interactions between T cells and dendritic cells in the immune system. The OPGL receptor, RANK, is expressed on chondrocytes, osteoclast precursors and mature osteoclasts. OPGL expression in T cells is induced by antigen receptor engagement, which suggests that activated T cells may influence bone metabolism through OPGL and RANK. Here we report that activated T cells can directly trigger osteoclastogenesis through OPGL. Systemic activation of T cells in vivo leads to an OPGL-mediated increase in osteoclastogenesis and bone loss. In a T-cell-dependent model of rat adjuvant arthritis characterized by severe joint inflammation, bone and cartilage destruction and crippling, blocking of OPGL through osteoprotegerin treatment at the onset of disease prevents bone and cartilage destruction but not inflammation. These results show that both systemic and local T-cell activation can lead to OPGL production and subsequent bone loss, and they provide a novel paradigm for T cells as regulators of bone physiology.

Anti-interleukin-1 and anti-tumor necrosis factor-α synergistically inhibit adjuvant arthritis in Lewis rats

Abstract. Interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-α) play dominant roles in mediating the progression of many inflammatory joint diseases, including rheumatoid arthritis in humans, collagen-induced arthritis in mice and rats, and adjuvant arthritis in rats. Blockade of either cytokine partially controls these diseases. The present study investigated the value of combination anti-cytokine therapy in arthritis: the efficacy of IL-1 receptor antagonist (IL-1ra) and 30 kDa polyethylene glycol (PEG)-conjugated soluble TNF receptor type I (PEG sTNF-RI) given together was assessed in Lewis rats with adjuvant arthritis. Administration of either IL-1ra or PEG sTNF-RI partially alleviated joint inflammation, loss of bone mineral density, and loss of body weight. In contrast, combination of these anti-cytokine treatments exhibited a synergistic capacity to inhibit these changes, even when combining doses of IL-1ra and PEG sTNF-RI that did not affect lesion severity when used alone. Statistical analysis of these adjuvant arthritis data using the isobologram method proved that IL-1ra and PEG sTNF-RI were clearly synergistic in inhibiting inflammation, loss of bone mineral density, loss of body weight, and histopathologic parameters of inflammation and joint destruction. These results suggest that treating autoimmune arthritic diseases with combinations of anti-IL-1 and anti-TNF molecules will achieve superior efficacy compared to the use of a single class of anti-cytokine agent and may allow for dose reductions that could prove useful in minimizing potential side effects.

RANKL is a Marker and Mediator of Local and Systemic Bone Loss in Two Rat Models of Inflammatory Arthritis

RANKL is an essential mediator of bone erosions, but the role of RANKL in systemic bone loss had not been studied in arthritis. RANKL protein was increased in rat joint extracts and serum at the earliest stages of arthritis. Osteoprotegerin (OPG) treatment reversed local and systemic bone loss, suggesting that RANKL is both a marker and mediator of bone loss in arthritis.

Design of PEGylated soluble tumor necrosis factor receptor type I (PEG sTNF-RI) for chronic inflammatory diseases

A recombinant C-terminal truncated form of the human soluble tumor necrosis factor receptor type I (sTNF-RI) was produced in E. coli. This soluble receptor contains the first 2.6 of the 4 domains of the intact sTNF-RI molecule. A monoPEGylated form of this molecule was produced using a 30 kD methoxyPEG aldehyde with approximately 85% selectivity for the N-terminal amino group. This molecule was shown to be less immunogenic in primates than the full length (4.0 domain) molecule or other versions of sTNF-RI which were either PEGylated at different sites or with different molecular weight PEGs. The 30 kD PEG also has a longer serum half-life to the molecule than lower molecular weight PEGs. This molecule markedly blunts the inflammatory response in a number of rheumatoid arthritis animal models. In addition, phase I/II and early phase II data in humans indicate that PEG sTNF-RI is non-immunogenic and that weekly dosing with this drug can reduce the number of tender and swollen joints in rheumatoid arthritis patients. PEG sTNF-RI has comparable American College of Rheumatology (ACR) efficacy scores as other anti-TNF molecules currently used to treat rheumatoid arthritic patients.

RANKL inhibition by osteoprotegerin prevents bone loss without affecting local or systemic inflammation parameters in two rat arthritis models: comparison with anti-TNFα or anti-IL-1 therapies

IntroductionRat adjuvant-induced arthritis (AIA) and collagen-induced arthritis (CIA) feature bone loss and systemic increases in TNFα, IL-1β, and receptor activator of NF-κB ligand (RANKL). Anti-IL-1 or anti-TNFα therapies consistently reduce inflammation in these models, but systemic bone loss often persists. RANKL inhibition consistently prevents bone loss in both models without reducing joint inflammation. Effects of these therapies on systemic markers of bone turnover and inflammation have not been directly compared.MethodsLewis rats with established AIA or CIA were treated for 10 days (from day 4 post onset) with either PBS (Veh), TNFα inhibitor (pegsunercept), IL-1 inhibitor (anakinra), or RANKL inhibitor (osteoprotegerin (OPG)-Fc). Local inflammation was evaluated by monitoring hind paw swelling. Bone mineral density (BMD) of paws and lumbar vertebrae was assessed by dual X-ray absorptiometry. Markers and mediators of bone resorption (RANKL, tartrate-resistant acid phosphatase 5b (TRACP 5B)) and inflammation (prostaglandin E2 (PGE2), acute-phase protein alpha-1-acid glycoprotein (α1AGP), multiple cytokines) were measured in serum (day 14 post onset).ResultsArthritis progression significantly increased paw swelling and ankle and vertebral BMD loss. Anti-TNFα reduced paw swelling in both models, and reduced ankle BMD loss in AIA rats. Anti-IL-1 decreased paw swelling in CIA rats, and reduced ankle BMD loss in both models. Anti-TNFα and anti-IL-1 failed to prevent vertebral BMD loss in either model. OPG-Fc reduced BMD loss in ankles and vertebrae in both models, but had no effect on paw swelling. Serum RANKL was elevated in AIA-Veh and CIA-Veh rats. While antiTNFα and anti-IL-1 partially normalized serum RANKL without any changes in serum TRACP 5B, OPG-Fc treatment reduced serum TRACP 5B by over 90% in both CIA and AIA rats. CIA-Veh and AIA-Veh rats had increased serum α1AGP, IL-1β, IL-8 and chemokine (C-C motif) ligand 2 (CCL2), and AIA-Veh rats also had significantly greater serum PGE2, TNFα and IL-17. Anti-TNFα reduced systemic α1AGP, CCL2 and PGE2 in AIA rats, while anti-IL-1 decreased systemic α1AGP, IL-8 and PGE2. In contrast, RANKL inhibition by OPG-Fc did not lessen systemic cytokine levels in either model.ConclusionsAnti-TNFα or anti-IL-1 therapy inhibited parameters of local and systemic inflammation, and partially reduced local but not systemic bone loss in AIA and CIA rats. RANKL inhibition prevented local and systemic bone loss without significantly inhibiting local or systemic inflammatory parameters.

Tumor necrosis factor α and RANKL blockade cannot halt bony spur formation in experimental inflammatory arthritis

OBJECTIVE To investigate the kinetics of bony spur formation and the relationship of bony spur formation to synovial inflammation and bone erosion in 2 rat arthritis models, and to address whether bony spur formation depends on the expression of tumor necrosis factor alpha (TNFalpha) or RANKL. METHODS Analysis of the kinetics of synovial inflammation, bone erosion, osteoclast formation, and growth of bony spurs was performed in rat collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA). In addition, inhibition experiments were performed to assess whether inhibition of TNFalpha and RANKL by pegylated soluble TNF receptor type I (pegTNFRI) and osteoprotegerin (OPG), respectively, affected bony spur formation. RESULTS Bony spurs emerged from the periosteal surface close to joints, and initial proliferation of mesenchymal cells was noted as early as 3 days and 5 days after onset of CIA and AIA, respectively. Initiation of bony spur formation occurred shortly after the onset of inflammation and bone erosion. Neither pegTNFRI nor OPG could significantly halt the osteophytic responses in CIA and AIA. CONCLUSION These results suggest that bony spur formation is triggered by inflammation and initial structural damage in these rat models of inflammatory arthritis. Moreover, emergence of bony spurs depends on periosteal proliferation and is not affected by inhibition of either TNFalpha or RANKL. Bony spur formation can thus be considered a process that occurs independent of TNFalpha and RANKL and is triggered by destructive arthritis.

The evolving systemic and local biomarker milieu at different stages of disease progression in rat adjuvant-induced arthritis.

IntroductionRats with adjuvant-induced arthritis (AIA) were necropsied on 14 occasions during preclinical, acute clinical and chronic clinical stages of AIA progression to characterize local (joint protein extracts) and systemic (serum) levels of mediators regulating inflammation and bone erosion in conjunction with lymphoid tissue-specific leukocyte kinetics.ResultsSystemic increases in alpha1 acid glycoprotein, tumor necrosis factor-α (TNFα), interleukin (IL)-17, transforming growth factor beta (TGFβ), and chemokine (C–C motif) ligand 2 (CCL2) together with local IL-1α/β and TGFβ enrichment and local lymphoid hyperplasia preceded the onset of clinical disease and joint damage. Systemic upregulation of TNFα, IL-6, IL-17, TGFβ, IL-18, CCL2, receptor activator of nuclear factor-κβ ligand (RANKL), and prostaglandin E2 during acute and/or chronic AIA coincided with systemic leukocytosis and CD4+ T cell increase in blood and spleen. In contrast, progression of joint erosions during clinical AIA was associated with intra-articular increases in IL-1α/β, IL-6, RANKL, IL-17, TGFβ, CCL2, and KC/GRO and also a dramatic decline in osteoprotegerin.ConclusionThese data indicate that systemic and local events in inflammatory arthritis are discrete processes, driven by multiple cellular and humoral mediators with distinct kinetic profiles.

Duration of bone protection by a single osteoprotegerin injection in rats with adjuvant-induced arthritis

Abstract. Daily osteoprotegerin (OPG) injection for 7 or more days prevents bone loss for 3 weeks in rats with adjuvant-induced arthritis (AdA). The present experiments defined the duration of bone protection in AdA provided by a single OPG bolus. Male Lewis rats received OPG at the onset or peak of clinical disease, after which bone mineral density (BMD), erosions, and osteoclasts were evaluated. An OPG bolus (4mg/kg subcutaneously) at onset eliminated osteoclasts, preserved BMD for 7 days, and prevented bone erosions for 4 days. In contrast, an OPG bolus (1, 3, 10, or 30mg/kg intravenously) given at the peak of disease eradicated osteoclasts in a dose-dependent manner but had no impact on bone integrity due to extensive pre-existing bone loss. These data indicate that one OPG injection will inhibit joint erosions for several days, and confirm that bone-sparing therapy must be initiated early in disease to protect joint integrity.

Treatment of rheumatoid arthritis with PEGylated recombinant human soluble tumour necrosis factor receptor type I: a clinical update

A recombinant form of the high affinity, natural inhibitor of tumour necrosis factor α (TNFα) is currently under development for the treatment of rheumatoid arthritis (RA).1 This molecule is referred to as recombinant-methionyl soluble TNF-type I receptor (r-metHu-sTNF-RI or sTNF-RI). Recombinant sTNF-RI is an Eschericia coli derived recombinant, truncated, monomeric form of the 4-domain soluble TNF-type I receptor. For optimal delivery, a high molecular weight (30 kDa) PEG molecule is attached at the N-terminus (met 1) position to form the molecule intended for clinical investigations (PEG r-metHu-sTNF-RI or PEG sTNF-RI). PEG sTNF-RI, with an approximate molecular weight of 42 kDa, has been designed for long term chronic subcutaneous (SC) administration for the treatment of RA. Preclinical studies to date demonstrate that PEG sTNF-RI is efficacious in rodent2-4 and primate5 models of acute and chronic inflammatory diseases, including E coli induced septic shock.6PEG sTNF-RI has demonstrated efficacy in predictive animal models of RA at doses as low as 0.3 mg/kg every other day.2 The results of these and other7-9 preclinical studies indicate that PEG sTNF-RI is a promising treatment for chronic inflammatory diseases. Eighty two subjects with active (for at least six months), moderate to severe RA (as defined by the American College of Rheumatology) were enrolled into this randomised, double blind, placebo controlled, dose escalation trial of safety and pharmacokinetics.10 Subjects were randomised to PEG sTNF-RI or placebo within one of two dose schedules. In schedule 1, subjects received a single dose of PEG sTNF-RI (100, 300, or 600 μg/kg) or placebo, followed six weeks later by weekly dosing for three weeks. In schedule 2, subjects received a single dose of PEG sTNF-RI (100, 300, or 600 μg/kg) or placebo every other week for six weeks. In addition, a group of subjects within schedules 1 and 2 received only a single dose …

The evolving systemic and local biomarker milieu at different stages of disease progression in rat collagen-induced arthritis

Rats with collagen-induced arthritis (CIA) were necropsied on 14 occasions from 4 days after induction to 27 days after disease onset to evaluate the kinetics of local (joint protein extracts) and systemic (serum) levels of inflammatory and pro-erosive factors. Systemic increases in α1 acid glycoprotein and KC/GRO together with systemic and local enrichment of interleukin (IL)-1β, IL-6, CCL2, transforming growth factor (TGF)-β and elevated IL-1α and IL-18 in joint extracts preceded the onset of clinical disease. Systemic upregulation of IL-1β, IL-6, TGF-β CCL2, RANKL and prostaglandin E2 (PGE2) during acute and/or chronic CIA coincided with systemic leukocytosis and a CD4+ T-cell increase in blood and spleen. In contrast, progression of joint erosions during clinical CIA was associated with intra-articular increases in IL-1α/β, IL-6, IL-18, CCL2, KC/GRO and RANKL, and a dramatic decline in osteoprotegerin (OPG). These data indicate that systemic and local events in inflammatory arthritis can be discrete processes, driven by multiple cellular and humoral mediators with distinct temporospatial profiles.