Current concepts in the therapy of the spondyloarthritides

Pharmacological inhibition of tumor necrosis factor may reduce pain behavior changes induced by experimental disc puncture in the rat: an experimental study in rats

STUDY DESIGN

Pain behavior assessment in rats following disc puncture (DP) and simultaneous tumor necrosis factor (TNF) inhibition.

OBJECTIVE

To assess if treatment with TNF inhibition could reduce the pain behavior changes induced by DP in the rat.

SUMMARY OF BACKGROUND DATA

Anular tears with leakage of nucleus pulposus have been suggested to be one possible cause of low back pain (LBP). In an experimental model, it was recently shown that DP might induce specific pain behavior changes. The aim of the present study was to a study if inhibition of TNF might reduce such pain behavior changes.

METHODS

Sixty rats underwent facetectomy and puncture of the fourth lumbar disc. The rats were simultaneously treated with doxycycline locally at 0.3 and 3.0 mg/kg and systemically at 3.0 mg/kg, or infliximab locally at 0.5 and 5.0 mg/kg, and systemically at 5.0 mg/kg, (n ∇ 10 for each subseries). The rats were videotaped at 1, 3, 7, 14, and 21 days after surgery. The videos were analyzed regarding presence of wet-dog shakes (WDS). Data from a previous study with sham surgery and DP without treatment were included for comparison.

RESULTS

All groups treated with doxycycline resulted in a statistically significant reduction of WDS compared to the group without treatment (DP). In infliximab treated animals, WDS decreased with statistically significance compared to the nontreated DP group at all analyzed days except for the group with high dose local treatment where a statistically significant reduction was obtained only at days 14 and 21.

CONCLUSION

The present study showed that TNF inhibition induced a marked reduction of wet dog shakes. It is not fully understood if wet-dog shakes may relate to LBP, but in view of recent clinical findings one may consider clinical studies of TNF inhibition for the treatment of LBP.

Etanercept: a review of its use in the management of ankylosing spondylitis and psoriatic arthritis

Etanercept (Enbrel), a recombinant, dimeric, soluble tumour necrosis factor (TNF) receptor protein, is approved in various countries for the treatment of adult patients with ankylosing spondylitis or psoriatic arthritis. Monotherapy with subcutaneous etanercept 25mg twice weekly or 50mg once weekly was effective and generally well tolerated in patients with ankylosing spondylitis or psoriatic arthritis participating in several large, well designed clinical studies. Treatment with etanercept was more effective than placebo in reducing disease activity and improving health-related quality of life (HR-QOL) in both patient populations, and in delaying structural disease progression in patients with psoriatic arthritis. The beneficial response to etanercept achieved with shorter-term treatment was sustained in studies of up to 4 years' total duration. Randomised, well designed, head-to-head comparisons, including pharmacoeconomic analyses, with other anti-TNF biological modulators are required to accurately position etanercept and fully establish its cost effectiveness. In the meantime, etanercept is a valuable treatment option for patients with ankylosing spondylitis or psoriatic arthritis who are suitable candidates for therapy.

TNF blockade: an inflammatory issue

Tumor necrosis factor (TNF), initially discovered as a result of its antitumor activity, has now been shown to mediate tumor initiation, promotion, and metastasis. In addition, dysregulation of TNF has been implicated in a wide variety of inflammatory diseases including rheumatoid arthritis, Crohn's disease, multiple sclerosis, psoriasis, scleroderma, atopic dermatitis, systemic lupus erythematosus, type II diabetes, atherosclerosis, myocardial infarction, osteoporosis, and autoimmune deficiency disease. TNF, however, is a critical component of effective immune surveillance and is required for proper proliferation and function of NK cells, T cells, B cells, macrophages, and dendritic cells. TNF activity can be blocked, either by using antibodies (Remicade and Humira) or soluble TNF receptor (Enbrel), for the symptoms of arthritis and Crohn's disease to be alleviated, but at the same time, such treatment increases the risk of infections, certain type of cancers, and cardiotoxicity. Thus blockers of TNF that are safe and yet efficacious are urgently needed. Some evidence suggests that while the transmembrane form of TNF has beneficial effects, soluble TNF mediates toxicity. In most cells, TNF mediates its effects through activation of caspases, NF-kappaB, AP-1, c-jun N-terminal kinase, p38 MAPK, and p44/p42 MAPK. Agents that can differentially regulate TNF expression or TNF signaling can be pharmacologically safe and effective therapeutics. Our laboratory has identified numerous such agents from natural sources. These are discussed further in detail.