Abdominal vagus nerve stimulation alleviates collagen-induced arthritis in rats.

Rheumatoid arthritis (RA) is a chronic, autoimmune inflammatory disease. Despite therapeutic advances, a significant proportion of RA patients are resistant to pharmacological treatment. Stimulation of the cervical vagus nerve is a promising alternative bioelectric neuromodulation therapeutic approach. However, recent clinical trials show cervical vagus nerve stimulation (VNS) was not effective in a significant proportion of drug resistant RA patients. Here we aim to assess if abdominal vagus nerve stimulation reduces disease severity in a collagen-induced arthritis (CIA) rat model. The abdominal vagus nerve of female Dark Agouti rats was implanted and CIA induced using collagen type II injection. VNS (1.6 mA, 200 µs pulse width, 50 µs interphase gap, 27 Hz frequency) was applied to awake freely moving rats for 3 h/day (days 11-17). At 17 days following the collagen injection, unstimulated CIA rats (n = 8) had significantly worse disease activity index, tumor necrosis factor-alpha (TNF-α) and receptor activator of NFκB ligand (RANKL) levels, synovitis and cartilage damage than normal rats (n = 8, Kruskal-Wallis: P < 0.05). However, stimulated CIA rats (n = 5-6) had significantly decreased inflammatory scores and ankle swelling (Kruskal-Wallis: P < 0.05) compared to unstimulated CIA rats (n = 8). Levels of tumor necrosis factor-alpha (TNF-α) remained at undetectable levels in stimulated CIA rats while levels of receptor activator of NFκB ligand (RANKL) were significantly less in stimulated CIA rats compared to unstimulated CIA rats (P < 0.05). Histopathological score of inflammation and cartilage loss in stimulated CIA rats were no different from that of normal (P > 0.05). In conclusion, abdominal VNS alleviates CIA and could be a promising therapy for patients with RA.

Paraneoplastic systemic lupus erythematosus associated with colorectal cancer.

A 64-year-old gentleman initially presented with nephrotic syndrome and membranous nephropathy with positive staining for C1q, which was suspicious for lupus membranous nephritis. Investigation led to the simultaneous diagnosis of colorectal cancer (CRC). The CRC was surgically excised and the patient's nephrotic syndrome resolved. The patient subsequently presented with classic systemic lupus erythematosus (SLE) including positive serological markers, mouth-ulcers and a photosensitive maculopapular rash. Two months later the patient represented with an SLE flare encompassing the full-hand of renal-pulmonary syndrome and vasculitic-neuropathy, importantly at this presentation occult recurrence of CRC was proven with tissue biopsy. Major histocompatibility class II haplotyping demonstrated HLA-DRB1*03, a known predisposition for SLE. This case depicts the scenario of tumour transformation triggering SLE development in a predisposed individual after an initial paraneoplastic manifestation in the form of membranous nephropathy (plus C1q). This supports the potential role of tumourgenesis in the development of SLE in a primed individual.

Is RANKL inhibition both anti-resorptive and anabolic in rheumatoid arthritis?

A small peptide, OP3-4, blocks receptor activator of NF-κB from binding to its ligand, receptor activator of NF-κB ligand (RANKL), and was reported recently to inhibit bone resorption, promote bone formation and protect cartilage in a preclinical rheumatoid arthritis model. The latter effects may result from inhibition of RANKL reverse signalling in osteoblasts and chondrocytes. Whether other RANKL inhibitors, such as denosumab, share this action is not known, but OP3-4 at least has potential to provide anabolic treatment for both systemic and focal bone loss in inflammatory arthritis.

Oncostatin M acting via OSMR, augments the actions of IL-1 and TNF in synovial fibroblasts.

OBJECTIVE: To identify how the gp130-signaling cytokine oncostatin M (OSM), acting alone or in concert with IL-1ß or TNFα, affects synovial fibroblast expression of genes relevant to inflammation and bone erosion in inflammatory arthritis. METHODS: Synovial fibroblasts (SFs) were isolated from non-arthritic wild type (WT) or OSM receptor deficient (OSMR(-/-)) mice and stimulated with OSM, IL-1ß or TNFα and their combinations. Cytokine gene expression was assessed by quantitative RT-PCR. ELISA, flow cytometry and immunohistochemistry identified protein expression. Gene expression patterns were confirmed in SFs isolated from patients with osteoarthritis (OASFs) and rheumatoid arthritis (RASFs). RESULTS: Expression of OSM and its receptors, gp130, OSMR and LIFR, was increased in synovial tissue from the mouse antigen-induced arthritis model. In isolated WT mouse synovial fibroblasts OSM alone, or in synergy with IL-1ß, or together with TNFα, potently induced expression of the pro-inflammatory cytokine IL-6. OSM also induced a sustained increase in mRNA levels of the pro-osteoclastic cytokine RANKL. Combining OSM with IL-1ß, but not with TNFα, further increased RANKL expression. Importantly these effects of OSM were all dependent on the expression of OSMR. Furthermore, OSM also increased expression of its own receptors, gp130 and OSMR and the IL-1 receptor, IL1-R1; the latter effects were also observed in both human OASFs and RASFs. CONCLUSION: Together our data suggests that OSM signaling via OSMR in SFs has the potential to contribute significantly to joint destruction in inflammatory arthritis. It not only induces expression of pro-inflammatory and pro-osteoclastic cytokines but can also augment its own actions and that of IL-1 by inducing expression of OSMR and IL-1R1.

The 'iron salute' in haemochromatosis.

The presentation of haemochromatosis is typified by abdominal pain, arthralgia and fatigue or weakness. Arthropathy may be the major presenting feature. The detection of an osteoarthritis-like process involving the metacarpophalangeal (MCP) and wrist joints in middle aged men should signal the possibility of under lying haemochromatosis. Other joints such as the shoulder, hip,knee or ankle may be affected. However, the preferential involvement of the second and third MCP joints is striking and may provide the opportunity for early identification of iron overload disease. The "iron salut" can be an efficient screening tool for this MCP joint arthropathy but it is not well known by clinicians.

Inflammation-induced bone loss: can it be prevented?

Inflammatory synovitis induces profound bone loss and OCLs are the instrument of this destruction. TNF blockers have an established role in the prevention of inflammatory bone loss in RA; however, not all patients respond to anti-TNF therapy and side effects may prevent long-term treatment in others. The B-cell--depleting antibody rituximab and the T-cell costimulation blocker abatacept are emerging as major treatment options for patients who are resistant to anti-TNF [96,97]. Proof-of-concept studies demonstrate that targeting RANK-mediated osteoclastogenesis prevents inflammatory bone loss and clinical application has only just begun. The efficacy of RANKL inhibition has been witnessed in trials of Denosumab, and RANKL-neutralizing antibodies are likely to become the treatment of choice for blocking RANKL in RA [77,78]. A major limitation of RANKL antagonism is that it does not treat synovitis. Therefore, anti-RANKL therapy most likely will be used in the context of MTX therapy. There is uncertainty about the possible extraskeletal adverse effects of long-term effects of long-term RANKL blockade. In particular, anti-RANKL therapy could jeopardize dendritic cell function or survival. The demonstrable role of OCLs in inflammation-induced bone loss also invites a reconsideration of the new BPs for bone protection [98]. Studies of ZA in preclinical models indicate that bone protection is comparable to that afforded by OPG. One possible caveat is that intravenous BPs are linked to jaw osteonecrosis [99], although the incidence is confined mainly to intensive treatment in the oncology setting. Although pulsed PTH stimulated bone formation in arthritic models, it has yet to be proven clinically in the context of powerful OCL inhibition with TNF or RANKL antagonists. With strategies that normalize OCL numbers, clinicians are poised to accomplish effective prevention of inflammation-induced bone loss.