An open study of pentoxyfylline and thalidomide as adjuvant therapy in the treatment of rheumatoid arthritis

Brief research report: Repurposing pentoxifylline to treat intense acute swimming-Induced delayed-onset muscle soreness in mice: Targeting peripheral and spinal cord nociceptive mechanisms

In this study, we pursue determining the effect of pentoxifylline (Ptx) in delayed-onset muscle soreness (DOMS) triggered by exposing untrained mice to intense acute swimming exercise (120 min), which, to our knowledge, has not been investigated. Ptx treatment (1.5, 4.5, and 13.5 mg/kg; i.p., 30 min before and 12 h after the session) reduced intense acute swimming-induced mechanical hyperalgesia in a dose-dependent manner. The selected dose of Ptx (4.5 mg/kg) inhibited recruitment of neutrophils to the muscle tissue, oxidative stress, and both pro- and anti-inflammatory cytokine production in the soleus muscle and spinal cord. Furthermore, Ptx treatment also reduced spinal cord glial cell activation. In conclusion, Ptx reduces pain by targeting peripheral and spinal cord mechanisms of DOMS.

Etanercept in erythema nodosum leprosum

One of the biggest challenges in treating leprosy is the control of reaction events. Patients with lepromatous leprosy may present reaction type II, or erythema nodosum leprosum, during treatment, and this reaction can remain in a recurrent form after being released from the hospital, requiring the use of thalidomide and/or prednisone for long periods of time, in turn increasing the risk of side effects. Two reports of the use of antiTNF to treat erythema nodosum leprosum were found in the literature. A good response was found after an assay with infliximab and etanercept. This study reports on a patient with lepromatous leprosy and recurrent reaction, controlled by using etanercept and a 10-month follow-up, with the interruption of thalidomide and the maintenance of prednisone at 10 mg/day.

Pharmacological studies on the anti-inflammatory and immunomodulatory role of pentoxifylline and its interaction with nitric oxide (NO) in experimental arthritis in rats

AIM

Present study was designed to evaluate protective effects of pentoxifylline and its potentiation with low dose of nitric oxide (NO) modulators in adjuvant-induced experimental arthritis in rats.

METHOD

Wistar rats (200-300 g, n = 8 per group) of both sexes were used in the study. On day "0" experimental arthritis was induced by injecting 0.2 ml of Complete Freund's adjuvant (CFA) in sub-planter region of right hind paw of animals. Pentoxifylline treatment alone and in combination with NO modulators was given (i.p.) from day 14 to 28. Various arthritic parameters were recorded and blood and joint synovial fluid was collected for biochemical analysis.

RESULTS

CFA inoculation significantly increases (1) arthritic index (2) ankle diameter (3) paw volume (4) histopathology score (5) serum TNF-α, IL-6, IL-1β and synovial TNF-α levels (p < 0.001) (6) serum Th₁ and Th₂ cytokine levels g) MDA levels in rat paw tissue homogenates (7) serum NF-κB levels. Significant decrease in serum IL-10 levels and SOD activity was observed in rats after CFA inoculation. Decrease in body weight and suppressed general quality of life of CFA inoculated rats was also observed. These CFA-induced arthritic changes were significantly reversed by pentoxifylline alone and in combination with low dose of NO modulators (p < 0.05).

CONCLUSION

These results are suggestive of protective effects of pentoxifylline and its potentiation in combination with low dose of NO modulators. These results may provide new pharmacological therapy for management of rheumatoid arthritis (RA).

Target-Based Drug Repositioning Using Large-Scale Chemical-Protein Interactome Data

Drug repositioning, or the identification of new indications for known drugs, is a useful strategy for drug discovery. In this study, we developed novel computational methods to predict potential drug targets and new drug indications for systematic drug repositioning using large-scale chemical-protein interactome data. We explored the target space of drugs (including primary targets and off-targets) based on chemical structure similarity and phenotypic effect similarity by making optimal use of millions of compound-protein interactions. On the basis of the target profiles of drugs, we constructed statistical models to predict new drug indications for a wide range of diseases with various molecular features. The proposed method outperformed previous methods in terms of interpretability, applicability, and accuracy. Finally, we conducted a comprehensive prediction of the drug-target-disease association network for 8270 drugs and 1401 diseases and showed biologically meaningful examples of newly predicted drug targets and drug indications. The predictive model is useful to understand the mechanisms of the predicted drug indications.

Thalidomide in dermatology: revisited

The use of thalidomide in relation to dermatology is well- known and enough data is available in the literature about various aspects of thalidomide. Despite being an interesting and useful drug for many dermatoses, it is associated with many health hazards including the birth defects, phocomelia. We hereby present a comprehensive review about thalidomide and its application in dermatology.

Pentoxifylline decreases allodynia and hyperalgesia in a rat model of neuropathic pain

BACKGROUND AND THE PURPOSE OF THE STUDY

Pentoxifylline (PTX) is a non-specific cytokite pain in several animal models and humans. However, long-term therapeutic effects of PTX on neuropathic pain in a rat model of chronic constriction injury (CCI) are not completely clear. This study was conducted to examine the effect of long-term administration of PTX on neuropathic pain in rats.

METHODS

Neuropathic pain was induced by sciatic nerve ligation using of CCI model in rats. Rats were randomly assigned into sham, CCI-saline treated, and CCI-PTX treated (30 or 60 mg/kg ip) groups. PTX or saline administered at 30 min before CCI and daily for 14 days post-CCI. At the days of 3, 7, 11 and 14 following CCI, by using standard methods effects of thermal hyperalgesia, thermal and mechanical allodynia in all groups were examined using the standard methods.

RESULTS

The CCI-saline treated group showed a significant increase in mechanical and thermal allodynia, and thermal hyperalgesia as compared with the sham group in the tested days. Administration of the higher dose of PTX (60 mg/kg/day), but not the lower dose (30 mg/kg/day) significantly reduced mechanical and thermal allodynia, as compared with the CCI-saline treated group on days of 3, 7, 11 and 14 (all P values<0.001). Also, both doses of PTX significantly reduced thermal hyperalgesia as compared with the CCI-saline treated group on these days (all P values<0.001).

CONCLUSION

Results of this study show that chronic administration of PTX reduces the neuropathic pain in a rat model of CCI. Thus, this drug may have a therapeutic application in the treatment and management of neuropathic pain in humans.

Angiogenesis inhibition as a therapeutic approach for inflammatory synovitis

Angiogenesis inhibition, long studied in the treatment of malignancies, has begun to emerge as a potential therapeutic approach in managing inflammatory arthritis, particularly rheumatoid arthritis. The growth of new vessels is required for the development of the rheumatoid pannus, which then leads to extensive synovial inflammation and joint destruction. Vascular endothelial growth factor is the best studied mediator of angiogenesis, and several therapies have been developed that specifically target this molecule. Several other angiogenesis mediators, such as the angiopoietin-TIE system, hypoxia inducible factor and integrin alpha(V)beta(3), as well as naturally occurring inhibitors of angiogenesis, are also being investigated as potential therapeutic targets. Additionally, there are a number of drugs, including paclitaxel, 2-methoxyestradiol and fumagillin analogs, that might have a role in inhibiting angiogenesis and, thus, in treating proliferative synovitis.

Pentoxifylline : l'anti-TNF du pauvre ?

PURPOSE

Pentoxifylline (PTX) is a phosphodiesterase inhibitor drug used to improve peripheral vascular disease. In vitro studies demonstrated that PTX has anti-TNFalpha properties. We did a selective review of clinical trials which used PTX in patients with inflammatory rheumatic and non-rheumatic diseases.

CURRENT KNOWLEDGE AND KEY POINTS

Most of the identified clinical trials were uncontrolled and involved a low number of patients. Use of PTX in systemic lupus erythematous, Behçet's disease and sarcoidosis yielded significant preliminary results. Moreover, PTX markedly reduced proteinuria in several glomerulonephritis (lupus nephritis, membranous nephropathy, diabetic nephropathy).

FUTURE PROSPECTS AND PROJECTS

Further randomized and controlled clinical trials are required to examine whether PTX can improve outcome in patients with inflammatory diseases. Meanwhile, PTX should not be used for the treatment of these diseases.

Anti-nociceptive effect of thalidomide on zymosan-induced experimental articular incapacitation

The anti-nociceptive effect of thalidomide on zymosan-induced articular knee joint incapacitation in rats was investigated. Thalidomide (5-45 mg/kg), given 30 min before but not 2 h after the intra-articular injection of zymosan, inhibited the nociceptive response in a dose-dependent manner. Furthermore, thalidomide pretreatment significantly reduced the concentration of tumor necrosis factor-alpha (TNF-alpha, -68.4%) in the exudate of zymosan-injected joints, but not those of interleukin-1beta, interleukin-6, CINC-1 or interleukin-10. The expression of TNF-alpha, determined by immunohistochemical staining, in synovial tissues obtained from articular joints injected with zymosan was also inhibited by thalidomide pretreatment. The anti-nociceptive effect of thalidomide was not reversed by the co-administration of an opioid receptor antagonist, naloxone, suggesting that endogenous opioids do not mediate the anti-nociceptive effect of thalidomide in this model. In conclusion, the anti-nociceptive activity of thalidomide in zymosan-induced articular incapacitation is associated with the inhibition of TNF-alpha by resident synovial cells.

Drugs to suppress cough

Cough is an important defensive reflex of the airway and also a common symptom of respiratory disease. Cough after common respiratory virus infection is transient but is more persistent when associated with conditions such as asthma, rhinosinusitis, gastro-oesophageal reflux, chronic obstructive pulmonary disease and lung cancer. Persistent cough may be due to peripheral and/or central sensitisation of cough reflexes initiated by cough receptors, rapidly adapting receptors or nociceptors. Treatment directed at associated conditions such as asthma (with anti-inflammatories) and gastro-oesophageal reflux (with proton-pump inhibitors) improve cough. There remains a need to use drugs that suppress the neural activity of cough (termed nonspecific), as treatments directed at the clinical cause(s) of the underlying cough (termed specific) may not be effective. The most effective indirect antitussives are opioids such as morphine, codeine or pholcodeine, but they produce side effects such as drowsiness, nausea, constipation and physical dependence. Opioids such as kappa- and delta-receptor agonists, non-opioids such as nociceptin, neurokinin and bradykinin receptor antagonists, cannabinoids, vanilloid receptor-1 antagonists, blockers of Na+-dependent channels, and large conductance Ca2+-dependent K+-channel activators of afferent nerves may represent novel antitussives.

New antiangiogenic strategies for the treatment of proliferative synovitis

Angiogenesis inhibition, which has been extensively studied for the treatment of various malignancies, is beginning to emerge as a new potential therapy for proliferative synovitis, particularly rheumatoid arthritis (RA). The rheumatoid pannus, the site of inflammation and joint destruction in the rheumatoid synovium, relies on the development of new vasculature to sustain its growth. A host of mediators have been shown to induce angiogenesis at the site of the inflamed synovium; these include vascular endothelial growth factor, fibroblast growth factor, integrin alpha(V)beta3, angiopoietin, prosta-glandin E1 and prostaglandin E2, and matrix metalloproteinases. In addition, hypoxia at the site of synovial inflammation contributes to angiogenesis stimulation. Several naturally-occurring inhibitors exist, such angiostatin and endostatin. There are a number of drugs undergoing study in the treatment of proliferative synovitis, which capitalise on the correlation between angiogenesis inhibition and the reduction of signs and symptoms of RA. Paclitaxel and an anti-integrin alpha(V)beta3 antibody, LM-609, are currently in clinical trials. Other drugs that may inhibit angiogenesis in RA include TNP-470 (formerly called AGM-1470), PPI-2458, PTK-787, bevacizumab and thalidomide. Many of these drugs have shown promise for the treatment of oncologic disorders, and are now being evaluated for the treatment of proliferative synovitis.

Antihyperalgesic effect of pentoxifylline on experimental inflammatory pain

The antihyperalgesic effect of pentoxifylline was investigated in three experimental pain models. Pentoxifylline (0.5-1.6 mg kg(-1)) given 30 min before the stimulus significantly inhibited the writhing response induced by the intraperitoneal (i.p.) administration of either acetic acid (-90%) or zymosan (-83%), but not that of iloprost, in mice, as well as the zymosan-induced articular hyperalgesia in the zymosan arthritis in rats (-50%). Pentoxifylline also inhibited the mechanical hypernociception in rats induced by the intraplantar injection of either carrageenin (-81%), bradykinin (-56%) or tumor necrosis factor alpha (TNF-alpha; -46%), but not that induced by interleukin-1beta (IL-1beta) or prostaglandin E(2) (PGE(2)). Pentoxifylline did not inhibit the nociceptive response in the hot plate test in mice. Further, the antinociceptive effect of pentoxifylline in the writhing test in mice and the zymosan-induced articular hyperalgesia were not reversed by the coadministration of the opioid receptor antagonist naloxone. Thus, pentoxifylline antinociceptive effect is probably not mediated at a central level. Pentoxifylline significantly reduced TNF-alpha (-43%) and IL-1beta (-42%) concentrations in the joint exudates of rats stimulated by intra-articular injection of zymosan and the production of both cytokines (-66 and -86%, respectively) by mouse peritoneal macrophages stimulated in vivo with zymosan as well as the expression of TNF-alpha at the tissue level in carrageenin-injected rat paws. In conclusion, the antinociceptive activity of pentoxifylline is associated with the inhibition of the release of both TNF-alpha and IL-1beta.

Inhibiting cytokines of the interleukin-12 family: recent advances and novel challenges

Interleukin-12 (IL-12) and the more recently discovered IL-23 and IL-27 constitute a unique family of structurally related, heterodimeric cytokines that regulate cell-mediated immune responses and T helper 1 (Th1)-type inflammatory reactions. Not surprisingly, the potentiality of treating conditions such as multiple sclerosis (MS) and rheumatoid arthritis (RA) through pharmacological interference with IL-12 pathways has received widespread attention. In this review we have examined over 50 substances with reported IL-12 inhibitory effects. We demonstrate that a majority of these belong to a limited number of major functional classes, each of which targets discrete events in the IL-12 biological pathway. Thus, most IL-12 inhibitory substances appear to work either through inhibition of transcription factor NF-kappa B activation, up-regulation of intracellular cAMP, blockage of posttranslational processing or interference with signal transduction pathways. In addition, cyclophilin-binding drugs, and generic inhibitors of nuclear histone deacetylases, and of ion channels, pumps and antiporters are emerging as potential leads to novel targets for interference with IL-12 production. Many inhibitors of NF-kappa B and of IL-12 signal transduction have been proven effective in limiting or preventing disease in experimental autoimmune encephalomyelitis (EAE) models of MS. The sharing of the p40 subunit, the IL-12R beta 1 and components of the signal transduction pathways between IL-12 and IL-23 raises the question as to whether the beneficial effects of various drugs previously ascribed to inhibition of IL-12 may, in fact, have been due to concurrent blockage of both cytokines, or of IL-23, rather than IL-12. Moreover, the homodimeric beta(2)-form of IL-12, though originally considered to display only antagonistic effects, is now emerging as a pronounced agonist in a variety of inflammatory processes. Reassessment of IL-12 inhibitory compounds is therefore needed to scrutinize their effects on IL-12 alpha beta, beta(2) and IL-23 formation. This is likely to open exciting perspectives to the identification of drugs that target these cytokines either indiscriminately or selectively. The functional diversity of presently available inhibitors should facilitate an unprecedented flexibility in designing future trials for the treatment of IL-12- and IL-23-mediated disorders.

Thalidomide

Despite its history as a human teratogen, thalidomide is emerging as a treatment for cancer and inflammatory diseases. Although the evolution of its clinical application could not have been predicted from the tragedy associated with its misuse in the past, its history serves as a lesson in drug development that underscores the need to understand the molecular pharmacology of a compound's activity, including associated toxicities. Here, we summarise the applications for thalidomide with an emphasis on clinical trials published over the past 10 years, and consider our knowledge of the molecular pharmacology of the drug in the context of clinical trial data, attempting to provide a mechanism-guided understanding of its activity.

Is there any future for tumor necrosis factor antagonists in chronic heart failure?

Over the past decade, a large number of studies have demonstrated that tumor necrosis factor-alpha (TNFalpha) plays an important role in the development of heart failure. Indeed, administration of TNFalpha to experimental animals and transgenic over-expression of TNFalpha replicate the heart failure phenotype. Furthermore, attenuation of the biologic activity of TNFalpha abrogates the development of heart failure in model systems. These pre-clinical studies, suggested that anti-cytokine therapy could prove beneficial in the treatment of patients with heart failure. While early studies supported this hypothesis, anti-TNF strategies have not demonstrated salutary benefits in large, multicenter randomized and placebo-controlled clinical trials in patients with symptomatic heart failure. This finding was disappointing. However, recent studies might provide clarification of this conundrum. For example, the failure to elicit beneficial effects with anti-cytokine therapy might be explained by novel pharmacogenomic or pharmacodynamic effects, the design of the Phase III clinical trials, or discordance between animal models and the human condition. Thus, appropriately designed clinical trials and newer anticytokine agents may demonstrate benefit.

Thalidomide and its derivatives: emerging from the wilderness

Forty years on from its worldwide withdrawal, thalidomide is currently undergoing a remarkable renaissance as a novel and powerful immunomodulatory agent. Over the last decade it has been found to be active in a wide variety of inflammatory and malignant disorders where conventional therapies have failed. Recently, considerable progress has been made in elucidating its complex mechanisms of action, which include both anticytokine and antiangiogenic properties. However, in addition to its well known teratogenic potential, it has a significant side effect profile that leads to cessation of treatment in up to 30% of subjects. In response to this, two new classes of potentially safer and non-teratogenic derivatives have recently been developed. This review summarises the biological effects, therapeutic applications, safety profile, and future potential of thalidomide and its derivatives.

Therapy of ankylosing spondylitis and other spondyloarthritides: established medical treatment, anti-TNF-alpha therapy and other novel approaches

Therapeutic options for patients with more severe forms of spondyloarthritis (SpA) have been rather limited in recent decades. There is accumulating evidence that anti-tumor-necrosis-factor (anti-TNF) therapy is highly effective in SpA, especially in ankylosing spondylitis and psoriatic arthritis. The major anti-TNF-alpha agents currently available, infliximab (Remicade(R)) and etanercept (Enbrel(R)), are approved for the treatment of rheumatoid arthritis (RA) in many countries. In ankylosing spondylitis there is an unmet medical need, since there are almost no disease-modifying antirheumatic drugs (DMARDs) available for severely affected patients, especially those with spinal manifestations. Judging from recent data from more than 300 patients with SpA, anti-TNF therapy seems to be even more effective in SpA than in rheumatoid arthritis. However, it remains to be shown whether patients benefit from long-term treatment, whether radiological progression and ankylosis can be stopped and whether long-term biologic therapy is safe.

Thalidomide in cancer treatment: a potential role in the elderly?

There is increased interest in the treatment of cancer with thalidomide because of its antiangiogenic, immunomodulating and sedative effects. In animal models, the antitumour activity of thalidomide is dependent on the species, route of administration and coadministration of other drugs. For example, thalidomide has shown antitumour effects as a single agent in rabbits, but not in mice. In addition, the antitumour effects of the conventional cytotoxic drug cyclophosphamide and the tumour necrosis factor inducer 5,6-dimethylxanthenone-4-acetic acid (DMXAA) were found to be potentiated by thalidomide in mice bearing colon 38 adenocarcinoma tumours. Further studies have revealed that thalidomide upregulates intratumoral production of tumour necrosis factor-alpha 10-fold over that induced by DMXAA alone. Coadministration of thalidomide also significantly reduced the plasma clearance of DMXAA and cyclophosphamide. All these effects of thalidomide may contribute to the enhanced antitumour activity. Recent clinical trials of thalidomide have indicated that it has minimal anticancer activity for most patients with solid tumours when used as a single agent, although it was well tolerated. However, improved responses have been reported in patients with multiple myeloma. Palliative effects of thalidomide on cancer-related symptoms have also been observed, especially for geriatric patients with prostate cancer. Thalidomide also eliminates the dose-limiting gastrointestinal toxic effects of irinotecan. There is preliminary evidence indicating that the clearance of thalidomide may be reduced in the elderly. The exact role of thalidomide in the treatment of cancer and cancer cachexia in the elderly remains to be elucidated. However, it may have some value as part of a multimodality anticancer therapy, rather than as a single agent.

Small therapeutic molecules for the treatment of inflammatory bowel disease

New therapies for inflammatory bowel disease are needed, because standard therapies fail to induce remission in about 30% of patients, and because of the relative inefficacy of current maintenance therapies. This review summarises the current status of the development of small therapeutic molecules for inflammatory bowel disease.

Thalidomide reduces tumour necrosis factor alpha and interleukin 12 production in patients with chronic active Crohn's disease

BACKGROUND

Thalidomide improves clinical symptoms in patients with therapy refractory Crohn's disease, as shown in two recent studies. The mechanism of this effect however is still unknown. Suppression of tumour necrosis factor alpha (TNF-alpha) by thalidomide has been suggested as a possible mechanism. However, effects on other cytokines have not been adequately investigated.

AIM

The aim of our study was to investigate the effects of thalidomide on cytokine production in patients with inflammatory bowel disease (IBD).

METHODS

Ten patients with therapy refractory IBD (nine Crohn's disease, one ulcerative colitis) received thalidomide 300 mg daily in a 12 week open label study. Production of TNF-alpha, interleukin (IL)-1 beta, IL-6, and IL-12 was investigated in short term cultures of stimulated colonic lamina propria mononuclear cells (LPMC) and peripheral blood monocytes (PBMC) before and after 12 weeks of treatment. LPMC were also cultured with graded doses of thalidomide.

RESULTS

Three patients discontinued treatment because of sedative side effects. In the other patients, disease activity decreased significantly, with four patients achieving remission. Production of TNF-alpha and IL-12 decreased during treatment with thalidomide: LPMC (TNF-alpha: 42.3 (8.3) pg/ml v 16.4 (6.3); IL-12: 9.7 (3.3) v 5.0 (2.5); p<0.04) and PBMC (TNF-alpha: 62.8 (14.6) v 22.5 (9.2); p<0.02). Production of IL-1 beta and IL-6 did not change significantly. Culturing of LPMC with thalidomide showed a dose dependent decrease in TNF-alpha and IL-12 production.

CONCLUSION

The clinical effects of thalidomide in Crohn's disease may be mediated by reduction of both TNF-alpha and IL-12.

The modification of human tumour blood flow using pentoxifylline, nicotinamide and carbogen

AIM

To assess the effect of combining oral nicotinamide, oral pentoxifylline and carbogen gas (2% CO2, 98% O2) breathing on human tumour red cell flux.

METHODS AND MATERIALS

Microregional red blood cell flux was measured in accessible tumour nodules using laser Doppler microprobes in 11 patients with histologically proven malignancy. Patients received single oral doses of nicotinamide 40 mgkg-1 and pentoxifylline 1200 mg 2h before a 10-min period of carbogen gas breathing, corresponding to peak plasma concentrations of these drugs. Red cell flux in up to six microregions in each tumour was measured for 30 min, recording pre-, during and post-carbogen breathing for 10 min each.

RESULTS

Data from ten of the 11 patients could be assessed. The red cell flux in 48 microregions was analysed and the mean red cell flux was calculated. A mean relative increase in red cell flux of 1.18 (+/-0.09, 95% confidence interval (CI)) was observed after 6 min of carbogen breathing, 2h after the administration of nicotinamide and pentoxifylline. This compares to relative increases of 1.4 (+/-0.39, 95%CI) after nicotinamide with carbogen and 1.15 (+/-0.10, 95%CI) after pentoxifylline with carbogen. These differences are not statistically significant (P>0.05). The increased red cell flux persisted after the cessation of carbogen gas breathing.

CONCLUSIONS

A combination of pentoxifylline, nicotinamide and carbogen produces an increase in human tumour red cell flux, similar to that observed when each of the drugs are used alone with carbogen breathing.

Thalidomide: new indications?

Thalidomide, which was developed as a nonbarbiturate sedative agent, was taken off the market in 1961 after it was linked to a spate of major birth defects. Gradually, thalidomide was reintroduced for the treatment of a few skin diseases including leprous erythema nodosum, severe mucosal ulcers (e.g., associated with HIV infection or Behçet's disease), lymphocytic skin infiltrations, cutaneous lupus erythematosus, and chronic graft-versus-host disease. Recent reports of original pharmacological properties including modulation of cytokine production (mainly reduced TNF-alpha production) and inhibition of angiogenesis have led to the suggestion that thalidomide may be useful in some inflammatory and neoplastic conditions. Several open-label studies and case reports have described the effects of thalidomide in Crohn's disease, rheumatoid arthritis, ankylosing spondylarthritis, systemic sclerosis, and a few other systemic disorders. In these indications, minor but dose-limiting side effects were apparently common. Thalidomide analogs with better acceptability profiles are under evaluation. The anti-angiogenic effects of thalidomide may make this compound valuable as single-drug therapy or as an adjunct to chemotherapy in patients with cancer, particularly those with metastases or multiple myeloma. This possibility requires further evaluation.

Combination therapy including pentoxifylline for entero-Behçet's disease

Behçet's disease is a chronic relapsing vasculitis characterized by recurrent aphthous oral and genital ulcerations with uveitis. Multiple organs can be involved. Entero-Behçet's disease is often uncontrollable, relapsing, and can cause acute intestinal bleeding or perforation. We utilized a combination therapy including 600 mg of pentoxifylline per day, in two doses, to treat three female patients and observed the subsequent changes in clinical symptoms, serum C reactive protein levels, and endoscopic findings. In all three patients, clinical symptoms as well as serum C reactive protein levels improved immediately. Endoscopically, lower intestinal lesions were significantly reduced or healed in all of them. Combination therapy including pentoxifylline appears to be clinically effective in the patients with entero-Behçet's disease.

Oral pentoxifylline inhibits release of tumor necrosis factor-alpha from human peripheral blood monocytes : a potential treatment for aseptic loosening of total joint components

BACKGROUND

Pentoxifylline (Trental) is a methylxanthine-derivative drug that has been used for more than twenty years in the treatment of peripheral vascular disease. Pentoxifylline is also a potent inhibitor of tumor necrosis factor-alpha (TNF-alpha) secretion, both in vitro and in vivo, and has demonstrated efficacy in the treatment of certain animal and human inflammatory diseases. Pentoxifylline has a potential therapeutic role in the treatment of aseptic loosening of total joint replacement components because it inhibits TNF-alpha secretion by particle-stimulated human peripheral blood monocytes. The purpose of our study was to determine whether the particle-stimulated secretion of TNF-alpha by peripheral blood monocytes was inhibited in volunteers who had received pentoxifylline orally.

METHODS

Human peripheral blood monocytes were harvested from eight healthy volunteers and were exposed to three different concentrations of titanium particles or to 500 ng/mL of lipopolysaccharide as a positive control. The same volunteers were then given pentoxifylline (400 mg, five times per day) for seven days. Their peripheral blood monocytes were again isolated and exposed to experimental conditions, and the TNF-alpha levels were measured.

RESULTS

The peripheral blood monocytes from all eight volunteers showed a significant reduction in TNF-alpha release following oral treatment with pentoxifylline. This reduction was observed at exposures of 10(7) and 10(6) titanium particles/mL and in the lipopolysaccharide-treated group, but not at 10(5) particles/mL.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate the ability of an oral drug to decrease the release of TNF-alpha from human peripheral blood monocytes exposed ex vivo to particle debris. TNF-alpha is involved in the pathogenesis of osteolysis and subsequent loosening of total joint arthroplasty components. The ability to suppress the release of TNF-alpha in patients with a total joint replacement may help to control osteolysis and to reduce the development of aseptic loosening. This effect could increase implant longevity and decrease the need for revision arthroplasty.

Extraintestinal Complications of Inflammatory Bowel Disease

Extraintestinal complications of inflammatory bowel disease (IBD) are often secondary to the underlying disease. Therefore, the first priority is to get active IBD into remission with medications, since surgery for IBD is not indicated for the treatment of extraintestinal complications. Symptoms of extraintestinal complications usually can be treated with simple agents; the treatment of patients with refractory symptoms and the use of more complex drug regimens should be done in cooperation with specialists on affected organ systems. Careful consideration of prescribed drugs is necessary because they may negatively influence the course of IBD.

Old and new drugs used in rheumatoid arthritis: a historical perspective. Part 2: the newer drugs and drug strategies

After a 20-year hiatus, drug development for rheumatoid arthritis resumed in the early 1980s with cyclosporine, continuing in the 1990s with minocycline, leflunomide, and the tumor necrosis factor-alpha antagonists, infliximab and etanercept. Unlike the older disease-modifying antirheumatic drugs (apart from the cytotoxics), the newer drugs were designed with strict reference to proven pathophysiology in rheumatoid arthritis and, apart from minocycline, the intended action of these agents is highly likely the explanation for the observed efficacy. The evidence for the evolution of more rational drug development in rheumatoid arthritis has not altered the fact that efficacy versus toxicity still remains the major determinant in the practical use of these agents, as well as in the use of other, experimental agents briefly discussed. Action, efficacy, and toxicity also determine the rational chronologic use of these drugs alone and, in particular, in combination.

Pentoxifylline induces the shedding of L-selectin on polymorphonuclear cells by stimulation via adenosine receptor as well as by the inhibition of phosphodiesterase

Abstract We investigated the effects of pentoxifylline (PTX) on the expression of L-selectin on polymorphonuclear leukocytes (PMN). PTX induced the down-regulation of L-selectin expression in dose- and time-dependent manner. The measurement of soluble L-selectin in the culture medium by ELISA indicated that the down-regulation of L-selectin expression by PTX was due to the shedding of L-selectin from PMN. The mechanism by which PTX induced the shedding of L-selectin was investigated. The concentration of intracellular cyclic AMP (cAMP) was increased after treatment of PMN with PTX. However, an elevation of cAMP induced by dibutyryl cAMP (dbcAMP) as well as other methylxanthine derivatives (caffeine, aminophylline, and theophylline) did not induce the shedding of L-selectin. Although stimulation of the adenosine receptor with 5'-N-ethylcarboxamidoadenosine (NECA) or 5'-(N-cyclopropyl)-carboxamido-adenosine (CPCA) adenosine receptor agonists did not induce the shedding of L-selectin, shedding of L-selectin was demonstrated when PMN was incubated simultaneously with rolipram, a phosphodiesterase (PDE) inhibitor, and CPCA. Moreover, shedding of L-selectin induced by PTX was attenuated by aminophylline, an adenosine receptor antagonist. These results indicated that PTX induces the shedding of L-selectin on PMN by stimulation via the adenosine receptor as well as inhibition of PDE.

Rheumatoid factors, anti-filaggrin antibodies and low in vitro interleukin-2 and interferon-gamma production are useful immunological markers for early diagnosis of community cases of rheumatoid arthritis. A preliminary study

OBJECTIVE

To determine whether measurements of different autoantibodies (Ab) and cytokines are useful to distinguish very early rheumatoid arthritis (RA) from other inflammatory rheumatisms.

METHODS

From a population-based recruitment, 32 patients with very early polyarthritis (median duration: 4 months) were studied. Evaluations at entry (M0), and at 6 (M6) and 12 months (M12). Ab tested: rheumatoid factors (RF) by agglutination methods and ELISA, antiperinuclear factor (APF), antikeratin Ab (AKA), anti-Sa and antinuclear Ab. Cytokine production (TNFalpha, IL2, IFNgamma, IL1beta, IL10) in whole blood cell culture (WBCC) was determined at M0. At M12, patients were classified as having RA (N = 15) or other rheumatic diseases.

RESULTS

At M0, AKA/APF and anti-Sa Ab frequencies were low, 13% and 7%, respectively. While most Ab detected at M0 persisted, others appeared during follow-up, particularly APF, which rose from 13 to 40% at M12. At M6, IgM-RF was detected in two RA patients exclusively by ELISA. AKA/APF were found to be highly specific markers for RA (100% specificity). At some time during follow-up, two RF-negative RA patients were AKA-positive. In two patients, AKA and APF were present at M0 before they satisfied ACR criteria. IL2 and IFNgamma production was significantly lower (P < 0.05) for RA patients.

CONCLUSION

AKA/APF and anti-Sa Ab were detected in community cases of very early RA. AKA/APF and RF detected by ELISA might contribute to an earlier diagnosis of RA. Low production of IFNgamma and IL2 in WBCC constituted a distinct immunopathological feature in very early RA patients.

Thalidomide treatment in chronic constrictive neuropathy decreases endoneurial tumor necrosis factor-alpha, increases interleukin-10 and has long-term effects on spinal cord dorsal horn met-enkephalin

Thalidomide reduces thermal hyperalgesia and mechanical allodynia in chronic constrictive sciatic nerve injury (CCI). Since thalidomide mainly inhibits tumor necrosis factor alpha (TNF-alpha) synthesis with less well defined effects on other cytokines, we investigated the effect of the drug on the expression of the proinflammatory cytokines TNF-alpha, interleukin-1beta (IL-1beta) and interleukin 6 (IL-6), and of the anti-inflammatory cytokine interleukin-10 (IL-10) in the lesioned rat sciatic nerve. The increase of endoneurial TNF-alpha during the first week after CCI was reduced after thalidomide treatment, as shown with immunohistochemistry and enzyme-linked-immunosorbent assay. In contrast, endoneurial IL-1beta-immunoreactivity (IR) and IL-6-IR were not altered by thalidomide treatment, nor was macrophage influx. Recruitment of epineurial IL-10 immunoreactive macrophages as well as the recovery of injury-induced depletion of endoneurial IL-10-IR was enhanced by thalidomide treatment. To control for central plasticity as another factor for the effects of thalidomide, the spinal cord was analyzed for changes in neurotransmitters. The decrease in CGRP-IR and SP-IR in the dorsal horn of operated animals was not influenced by treatment. In contrast, the increase in met-enkephalin observed in the dorsal horn of operated animals was further enhanced in the thalidomide-treated animals. The study elucidates some of the complex alterations in CCI and its modulation by thalidomide, and provides further evidence for a possible therapeutic benefit of cytokine-modulating substances in the treatment of neuropathic pain.

[Value of anti-TNF-alpha molecules in inflammatory and infectious diseases]

INTRODUCTION

The pathophysiological interest of tumor necrosis factor-alpha (TNF-alpha) has been recently reported in inflammatory and infectious diseases. Thus, TNF-alpha blockade has become a new field of therapeutical research.

CURRENT KNOWLEDGE AND KEY POINTS

Several biological agents specifically directed against TNF-alpha are available: anti-TNF-alpha monoclonal antibodies on the one hand--either mainly murine sequence (cA2), partially humanized (CDP 571) or fully human (D2E7)--and TNF-alpha soluble receptors on the other hand (lenercept or etanercept). The first clinical studies reveal interesting results. In rheumatoid arthritis (cA2, etanercept), these molecules may be used either alone or in synergistic combination with methotrexate. They produce a significant response compared to placebo or methotrexate alone, without loss of efficacy in medium-term treatment. In Crohn's disease (cA2 CDP571), they reduce significantly the activity of the disease, compared to placebo, and cA2 makes it possible to accelerate closure of the fistulas. The studies of severe sepsis did not reveal a significant efficacy, however, and only one study has been published on malignant disease, with a possible interesting effect. Even if these medications are usually well tolerated, the frequency of infections is slightly increased. The development of anti-DNA antibodies has also been reported, but drug-induced lupus is highly unusual.

FUTURE PROSPECTS AND PROJECTS

Further studies will define the place of anti-TNF-alpha biological agents among the other available treatments of rheumatoid arthritis and Crohn's disease. Because of their high cost, these drugs will probably be limited to patients with active inflammatory disease despite more conventional treatments.

Potential novel uses of thalidomide: focus on palliative care

Thalidomide, after being banned from the market in the early 1960s because of the worldwide teratogenesis disaster, is currently being rediscovered because of its multiple therapeutic effects in various serious diseases and symptoms. Original studies examined the anxiolytic, mild hypnotic, anti-emetic and adjuvant analgesic properties of this drug. Subsequently, thalidomide was found to be highly effective in managing the cutaneous manifestations of leprosy (erythema nodosum leprosum) and even to be superior to aspirin (acetylsalicylic acid) in controlling leprosy-associated fever. Recent research shows promising results with thalidomide in patients with progressive bodyweight loss related to advanced cancer and HIV infection. Thalidomide therapy of diseases such as tuberculosis, sarcoidosis, aphthous ulcers in HIV syndrome and Behcet's disease, rheumatoid arthritis, multiple myeloma, graft-versus-host disease, pyoderma gangrenosum, inflammatory bowel disease, Sjögren's syndrome, lupus erythematosus and a variety of solid tumours is currently being explored. Furthermore, in preliminary studies, thalidomide has been found to be effective in several syndromes related to advanced cancer, such as the cancer cachexia syndrome, chronic nausea, insomnia, profuse sweating and pain. Whether thalidomide has a therapeutic effect on neoplastic fever has yet to be elucidated. These intriguing features make the use of the drug potentially attractive for palliative care. In addition, by a distinct mechanism of action compared with most other drugs, thalidomide offers the possibility of combined treatment with other agents with non-overlapping toxicities. The mechanism of action of thalidomide is probably based on the suppression of tumour necrosis factor-alpha and the modulation of interleukins. However, it is not possible to identify a single dominant mechanism, since the action of cytokines and the effect of thalidomide appear to be complex. This review article discusses the original uses and teratogenic effects of thalidomide within its historical context and, linking recent research at the molecular level with clinical findings, aims to provide the reader with insight into the current understanding of its biological actions, toxicities and potential benefits.

The TH1 and TH2 cytokine network in healthy subjects: suggestions for experimental studies to create prognostic and diagnostic indices for biotherapeutic treatments

In vivo and in vitro studies have demonstrated the selective regulatory effect that TH1 and TH2 cytokines reciprocally exert in the regulation of the polarization of precursor cells into TH1 or TH2 types. The study of the network relationships between TH1 and TH2 (TH1/TH2) cytokines in healthy subjects could lead to a better understanding of how the physiological network of cytokines regulates the immune response. Such study could lead to gain suggestions for follow-up experiments to create prognostic and diagnostic indices for biotherapeutic treatments of patients. Hence we determined serum levels (environment network) and PBMC production (cellular network) of IL2, IFN gamma, IL4, IL6 and IL10 in the peripheral blood of healthy subjects; these cytokines made up our networks under basic conditions. Both men and women were studied as hormones can influence the polarization of TH1 and TH2 cells. Cytokines within the physiological network function simultaneously so multivariate statistical methods were used to study TH1/TH2 relationships. The use of mathematical modelling is the only effective way of studying the immune system as a whole. The physiological TH1/TH2 network under activation conditions was evaluated by incorporating: sIL2R and sIL6R into the basic environment network model and the production levels of cytokines by PBMC after PHA stimulus, into the basic cellular network model. The influence of APC was evaluated by adding: serum levels of TNF alpha and IL1 beta to the environment network model, and production levels of IFN gamma, IL10 and IL6, after stimulus with LPS, to the cellular network model. Our results led us to hypothesize that the physiological network of TH1/TH2 cytokines regulates TH polarization by means of specific relationships between TH1 and TH2 cytokines, which may be different in men and women. These relationships could be studied experimentally to create prognostic and diagnostic indices for more efficient prevention programs and biotherapeutic treatments of patients.

Thalidomide: current and potential clinical applications

More than three decades after its withdrawal from the world marketplace, thalidomide is attracting growing interest because of its reported immunomodulatory and anti-inflammatory properties. Current evidence indicates that thalidomide reduces the activity of the inflammatory cytokine tumor necrosis factor (TNF)-alpha by accelerating the degradation of its messenger RNA. Thalidomide also inhibits angiogenesis. Recently, the drug was approved for sale in the United States for the treatment of erythema nodosum leprosum, an inflammatory complication of Hansen's disease. However, it has long been used successfully in several other dermatologic disorders, including aphthous stomatitis, Behçet's syndrome, chronic cutaneous systemic lupus erythematosus, and graft-versus-host disease, the apparent shared characteristic of which is immune dysregulation. Many recent studies have evaluated thalidomide in patients with human immunodeficiency virus (HIV) infection; the drug is efficacious against oral aphthous ulcers, HIV-associated wasting syndrome, HIV-related diarrhea, and Kaposi's sarcoma. To prevent teratogenicity, a comprehensive program has been established to control access to the drug, including registration of prescribing physicians, dispensing pharmacies, and patients; mandatory informed consent and education procedures; and limitation of the quantity of drug dispensed. Clinical and, in some patients, electrophysiologic monitoring for peripheral neuropathy is indicated with thalidomide therapy. Other adverse effects include sedation and constipation. With appropriate safeguards, thalidomide may benefit patients with a broad variety of disorders for which existing treatments are inadequate.

Measurement of induced cytokines in AIDS clinical trials using whole blood: a preliminary report. ACTG Inducible Cytokines Focus Group. AIDS Clinical Trials Group

Measures of immune function have become increasingly important as endpoints in AIDS clinical trials, with respect to both modulation and reconstitution of immunity by experimental therapies. Measurement of immune function in this setting requires the development of robust analytic approaches suitable for the clinical laboratory. Experiments were performed to evaluate the suitability of using cultured heparinized ("whole") blood for induction of tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma), two cytokines critical in AIDS pathogenesis. TNF-alpha expression ranged from 229 to 769 pg/ml in lipopolysaccharide (LPS)-stimulated cultures and was not detected in unstimulated cultures. IFN-gamma expression ranged from 0 to 112,000 pg/ml in phytohemagglutinin A (PHA)-stimulated cultures and from 0 to 789 pg/ml in antigen-stimulated cultures. The mean coefficient of variation observed in three weekly determinations was 0.47 for TNF-alpha and ranged from 0.12 to 1.73 for IFN-gamma. These values indicate that sample sizes of 8, 24, and 29 subjects would be sufficient to detect twofold changes in LPS-induced TNF-alpha and in PHA- and antigen-induced IFN-gamma respectively, if two baseline and two treatment determinations were obtained, and if the interpatient variability of changes in true levels from baseline to follow-up is negligible compared to the variability in the three weekly measurements. Measurement of LPS-induced TNF-alpha and mitogen- or antigen-induced IFN-gamma can be performed simply and reproducibly in human immunodeficiency virus-infected persons by the whole-blood culture method. Further studies are warranted to determine the effect of overnight shipping on assay reproducibility and to determine the extent to which responses can be reliably detected in subjects with low CD4 cell numbers.

The future role of anti-tumour necrosis factor (TNF) products in the treatment of rheumatoid arthritis

Tumour necrosis factor-alpha (TNF alpha) is a pleiotropic cytokine which is overproduced in rheumatoid joints primarily by macrophages. This cytokine has a potential pathogenic role in the establishment of rheumatoid synovitis, in the formation of pannus tissue and in the process of joint destruction, as it increases synoviocyte proliferation and triggers a cascade of secondary mediators involved in the recruitment of inflammatory cells, in neo-angiogenesis and in the process of joint destruction. These findings made TNF alpha a potential target for anticytokine therapy. Experimental studies have shown that TNF alpha blockade by monoclonal antibodies or by soluble TNF receptor reduced the extent and severity of arthritis both in collagen-induced arthritis in mice and in transgenic mice overexpressing TNF alpha, which develop a rheumatoid-like destructive arthritis. Clinical studies based on the use of anti-TNF alpha antibodies or soluble receptors have suggested a potential beneficial effect of TNF alpha-blocking therapy in inducing amelioration of inflammatory parameters in patients with long-standing active disease. In these patients anti-TNF alpha therapy induces a rapid improvement in multiple clinical assessment of disease activity, including morning stiffness, pain score, Ritchie articular index and swollen joint count. The clinical benefits are associated with an improvement in some serological parameters, such as C-reactive protein and serum amyloid-A, erythrocyte sedimentation rate, blood cytokine levels, haemoglobin, white cells and platelet counts, rheumatoid factor titre and histological features of the synovium. However, it remains to be determined whether anti-TNF alpha therapy may be useful in the long term management of rheumatoid patients and in the achievement of better outcomes of disease. Because TNF alpha production also serves a specific function in host defence against infections and tumours, the adverse effects of long term anti-TNF alpha therapy must be carefully evaluated. In addition, targeting a single mediator may be not sufficient to block the complex inflammatory response in rheumatoid arthritis. For these reasons therapeutic strategies aimed at concomitantly interfering with multiple pathogenic pathways are currently under investigation.