Immune regulation in adjuvant disease and other arthritis models: relevance to pathogenesis of chronic arthritis

In vitro and in vivo modulatory effects of fluoxetine on gene expression and antioxidant enzymes in CFA-induced chronic inflammatory model: drug repurposing for arthritis

Fluoxetine, being a selective serotonin uptake inhibitor, has been broadly used to modulate the neurotransmission of serotonin in the central nervous system. Fluoxetine performs a number of crucial central nervous system-related tasks, including neuroprotective effects against microglial neurotoxicity and protecting oxidative cell damage produced by stress in a variety of stress-related unfavourable health disorders. Studies have shown that the drug (fluoxetine) also has analgesic and anti-inflammatory characteristics in addition to its other basic benefits. Furthermore, existing treatment approaches (NSAIDs, DMARDs, corticosteroids and other immunosuppressants) for RA have limited effects on chronic immunological models. These facts served as the basis for carrying out a study on fluoxetine to explore its therapeutics in a chronic inflammatory rat model called Freund's complete adjuvant (FCA)-induced arthritis. The therapeutic effect of the fluoxetine in FCA-induced arthritic rats was assessed by paw volume, paw diameter, arthritic index and body weight at specific days through the experiment of 28 days. These findings were further co-investigated by haematological, biochemical parameters and radiographic imaging at the end of experiment. Furthermore, the modulatory effects on gene expression (NF-κB, PGE2, COX2, INF-γ, IL-4 and IL-10) and antioxidant properties were gritty using qRT-PCR and ELISA kits, respectively, in experimental arthritic rats. Fluoxetine at 10, 20 and 40 mg/kg doses reduced (p < 0.001) the serum concentration of C-reactive protein and rheumatoid factor as well as suppressed the expression of PGE2, NF-kB, COX2 and INF-γ when compared to arthritic control. Moreover, fluoxetine (at higher doses) caused significant rise of IL-4 and IL-10. These findings supported the anti-inflammatory and antioxidant potential of fluoxetine in chronic inflammatory model and endorsed it for clinical trials.

Enalapril attenuated CFA provoked arthritic manifestation by modulating proinflammatory and anti-inflammatory cytokine network

Enalapril with documented anti-inflammatory potential was evaluated in current investigation to explore its anti-arthritic efficacy. For anti-arthritic evaluation of enalapril, CFA-instigated arthritic model was employed after which various parameters comprising paw volume, body weight, arthritic index, hematological and biochemical parameters, radiographic analysis and level of various cytokines were estimated. Enalapril demonstrated significant (p˂0.001) anti-arthritic activity by suppressing paw volume, arthritic index while preserved CFA instigated weight loss. Likewise, enalapril also normalized the hematological and biochemical alterations, suppressed the level of proinflammatory cytokines with elevation of anti-inflammatory cytokines. Radiographic and histopathological analysis also further validates the anti-arthritic attribute of enalapril where enalapril preserved the normal architecture of arthritis induced joints. Outcomes of the study pointed out a notable anti-arthritic activity of enalapril. However detailed mechanistic studies are still required to point out the exact mechanism of action.

Effects of buprenorphine on acute pain and inflammation in the adjuvant-induced monoarthritis rat model

Background and aim

Animal modelling of arthritis is often associated with pain and suffering. Severity may be reduced with the use of analgesia which is, however, often withheld due to concerns of introducing a confounding variable. It is therefore important to design and validate pain relief protocols that reduce pain without compromising the scientific objectives. The present study evaluated the effect of buprenorphine analgesia in the immediate post-induction period of an adjuvant-induced monoarthritic rat model. The aim of this study was to extend previous work on refinement of the model by alleviating unnecessary pain.

Methods

Male and female Sprague Dawley rats were injected with 20 μl of complete Freund's adjuvant (CFA) into the left ankle. Rats were treated with buprenorphine, either injected subcutaneously or ingested voluntarily, and were compared to rats given subcutaneous injections with vehicle (saline or pure nut paste) or carprofen the first three days post CFA-injection. Measurements of welfare, clinical model-specific parameters and pain-related behaviour were assessed.

Results

Buprenorphine, administered either subcutaneously (0.10 or 0.15 mg/kg, twice daily) or by voluntary ingestion in nut paste (1.0 or 3.0 mg/kg, twice daily), improved mobility, stance, rearing and lameness scores significantly 7 h post CFA-injection. Mechanical hyperalgesia peaked at 7 h and was significantly lower in buprenorphine-treated animals, compared to vehicle-treated animals. Joint circumference was highest 24–72 h after CFA injection. Animals treated with buprenorphine did not decrease in joint circumference, opposite carprofen treated animals.

Conclusion

Buprenorphine, administered either subcutaneously or by voluntary ingestion, provides adequate analgesia for both sexes within the first 24 h post CFA-injection. Buprenorphine treatment improved clinical scores and appeared not to suppress the inflammatory response. The present study supports previous findings that voluntarily ingested buprenorphine is an effective alternative to repeated injections.

Preclinical characterization of itacitinib (INCB039110), a novel selective inhibitor of JAK1, for the treatment of inflammatory diseases

Pharmacological modulation of the Janus kinase (JAK) family has achieved clinically meaningful therapeutic outcomes for the treatment of inflammatory and hematopoietic diseases. Several JAK1 selective compounds are being investigated clinically to determine their anti-inflammatory potential. We used recombinant enzymes and primary human lymphocytes to assess the JAK1 specificity of itacitinib (INCB039110) and study inhibition of signal transducers and activators of transcription (STAT) signaling. Rodent models of arthritis and inflammatory bowel disease were subsequently explored to elucidate the efficacy of orally administered itacitinib on inflammatory pathogenesis. Itacitinib is a potent and selective JAK1 inhibitor when profiled against the other JAK family members. Upon oral administration in rodents, itacitinib achieved dose-dependent pharmacokinetic exposures that highly correlated with STAT3 pharmacodynamic pathway inhibition. Itacitinib ameliorated symptoms and pathology of established experimentally-induced arthritis in a dose-dependent manner. Furthermore, itacitinib effectively delayed disease onset, reduced symptom severity, and accelerated recovery in three distinct mouse models of inflammatory bowel disease. Low dose itacitinib administered via cannula directly into the colon was highly efficacious in TNBS-induced colitis but with minimal systemic drug exposure, suggesting localized JAK1 inhibition is sufficient for disease amelioration. Itacitinib treatment in an acute graft-versus-host disease (GvHD) model rapidly reduced inflammatory markers within lymphocytes and target tissue, resulting in a marked improvement in disease symptoms. This is the first manuscript describing itacitinib as a potent and selective JAK1 inhibitor with anti-inflammatory activity across multiple preclinical disease models. These data support the scientific rationale for ongoing clinical trials studying itacitinib in select GvHD patient populations.

1,25-Dihydroxyvitamin D3 attenuates disease severity and induces synoviocyte apoptosis in a concentration-dependent manner in rats with adjuvant-induced arthritis by inactivating the NF-κB signaling pathway

An aggressive proliferation of synoviocytes is the hallmark of rheumatoid arthritis (RA). Emerging evidence shows that inhibiting the NF-κB signaling pathway with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] may be a therapeutic approach for controlling inflammatory diseases. In this study, we demonstrated the protective effects of three different 1,25(OH)2D3 concentration on adjuvant-induced arthritis (AA) rats through the NF-κB signaling pathway and their pro-apoptotic roles in cultured adjuvant-induced arthritis synoviocytes (AIASs). AA rats were prepared by injecting complete Freund's adjuvant and independently given daily intraperitoneal injection of 1,25(OH)2D3 at concentrations of 50, 100, and 300 ng/day/kg. Subsequently, AIASs were isolated from the inflamed joints of AA rats to test the effects of 1,25(OH)2D3 on AIASs in vitro. Intraperitoneal injection of 1,25-(OH)2D3 was found to induce a concentration- and time-dependent improvement in relieving the symptoms of AA. We found an increased paw withdrawal thermal latency (PWTL) in the affected paw of AA rats as the concentration of 1,25-(OH)2D3 increased. 1,25-(OH)2D3 treatment reduced levels of inflammatory factors in synovial tissues of AA rats. In the case of cultured AIASs, 1,25-(OH)2D3 was shown to inhibit cell proliferation and induce cell apoptosis in a concentration-dependent manner. Additionally, 1,25-(OH)2D3 inhibited the activation of the NF-κB signaling pathway. In conclusion, our study provides evidence emphasizing that 1,25(OH)2D3 has the potential to attenuate disease severity in RA potentially due to its contributory role in synoviocyte proliferation and apoptosis. The protective role of 1,25(OH)2D3 against RA depends on the NF-κB signaling pathway.

Pain Relieving Effect of-NSAIDs-CAIs Hybrid Molecules: Systemic and Intra-Articular Treatments against Rheumatoid Arthritis

To study new target-oriented molecules that are active against rheumatoid arthritis-dependent pain, new dual inhibitors incorporating both a carbonic anhydrase (CA)-binding moiety and a cyclooxygenase inhibitor (NSAID) were tested in a rat model of rheumatoid arthritis induced by CFA intra-articular (i.a.) injection. A comparison between a repeated per os treatment and a single i.a. injection was performed. CFA (50 µL) was injected in the tibiotarsal joint, and the effect of per os repeated treatment (1 mg kg⁻¹) or single i.a injection (1 mg mL⁻¹, 50 µL) with NSAIDs-CAIs hybrid molecules, named 4 and 5, was evaluated. The molecules 4 and 5, which were administered daily for 14 days, significantly prevented CFA-induced hypersensitivity to mechanical noxious (Paw pressure test) and non-noxious stimuli (von Frey test), the postural unbalance related to spontaneous pain (Incapacitance test) and motor alterations (Beam balance test). Moreover, to study a possible localized activity, 4 and 5 were formulated in liposomes (lipo 4 and lipo 5, both 1 mg mL⁻¹) and directly administered by a single i.a. injection seven days after CFA injection. Lipo 5 decreased the mechanical hypersensitivity to noxious and non-noxious stimuli and improved motor coordination. Oral and i.a. treatments did not rescue the joint, as shown by the histological analysis. This new class of potent molecules, which is able to inhibit at the same time CA and cyclooxygenase, shows high activity in a preclinical condition of rheumatoid arthritis, strongly suggesting a novel attractive pharmacodynamic profile.

Effect of inositol -stabilized arginine silicate on arthritis in a rat model

The purpose of this study was to test the effects of arginine-silicate-inositol complex (ASI), compared to a combination of the individual ingredients (A+S+I) of the ASI, on inflammatory markers and joint health in a collagen-induced arthritis (CIA) rat model. A total of 28 Wistar rats were divided into four groups: (i) Control; (ii) Arthritic group, rats subjected to CIA induction by injection of bovine collagen type II (A); (iii) Arthritic group treated with equivalent doses of the separate components of the ASI complex (arginine hydrochloride, silicon, and inositol) (A+S+I); (iv) Arthritic group treated with the ASI complex. The ASI complex treatment showed improved inflammation scores and markers over the arthritic control and the A+S+I group. ASI group had also greater levels of serum and joint-tissue arginine and silicon than the A+S+I group. Joint tissue IL-6, NF-κB, COX-2, TNF-α, p38 MAPK, WISP-1, and β-Catenin levels were lower in the ASI group compared to the other groups (P < 0.05 for all). In conclusion, these results demonstrate that the ASI complex may be effective in reducing markers of inflammation associated with joint health and that the ASI complex is more effective than a combination of the individual ingredients.

Anti-rheumatoid arthritis effects in adjuvant-induced arthritis in rats and molecular docking studies of Polygonum orientale L. extracts

BACKGROUND AND PURPOSE

Polygonum orientale L. (family: Polygonaceae), named Hongcao in China, has effects of dispelling wind and dampness, promoting blood circulation, and relieving pain. Our group has already studied and confirmed that POEa and POEe (ethyl acetate and ethyl ether extract of P. orientale, respectively) had anti-inflammatory and analgesic effects in early research, which was mainly relevant to the existence of flavonoids. According to the clinical application of P. orientale in traditional Chinese medicine, it has long been used for rheumatic arthralgia and rheumatoid arthritis. Therefore, our group further explored whether flavonoids of P. orientale have anti-rheumatoid arthritis effect and how does they play this role.

METHODS

Dried small pieces of the stems and leaves of P. orientale were decocted with water and partitioned successively to obtain POEa and POEe, respectively. The anti-rheumatoid arthritis effect of P. orientale was studied by using a Freund's complete adjuvant (FCA)-induced arthritis (AIA) in a rat model. The levels of PGE2, TNF-α, and IL-1β in serum of AIA rats were detected by enzyme linked immunosorbent assay (ELISA) to explore its mechanisms. In addition, we computationally studied the relationships between the 15 chemical components of POEa and POEe, and the currently focused 9 target proteins of rheumatoid arthritis by molecular docking.

RESULTS

Pharmacological experiments showed that POEa and POEe significantly ameliorate symptoms of rheumatoid arthritis via reducing paw swelling volume, arthritis score, and thymus and spleen indices, as well as increasing body weight in AIA rats. Simultaneously, the concentrations of PGE2, TNF-α, and IL-1β were significantly decreased by POEa and POEe. Histopathology revealed noticeable reduction in bone and cartilage, synovial hyperplasia, inflammatory cell infiltration, cartilage surface erosion, and joint degeneration by POEa and POEe treatment. In addition, the molecular docking studies showed that docking scores of 14 chemical compositions (including 12 flavonoids and 2 phenolic acids) of POEa and POEe with anti-rheumatoid arthritis protein targets were better than the complexed ligands of the anti-rheumatoid arthritis protein targets. Among them, six flavonoids in POEa and POEe had more docking protein targets (n ≥ 3). Five anti-rheumatoid arthritis targets including high-temperature requirement A1 protease (HtrA1), janus kinase 1 (JAK1), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (i-NOS), and prostaglandin E2 (PGE2) had better docking score compared with the complexed ligands. Moreover, most of the chemical components in POEa and POEe showed strong interaction with HtrA1.

CONCLUSIONS

The flavonoids of P. orientale have anti-rheumatoid arthritis effect. In addition, the molecular docking results indicate that quercetin, catechol, orientin, and other six flavonoids may be closely related to HtrA1, JAK1, COX-2, i-NOS, and PGE2 protein target receptors. It suggests that these chemical compositions form strong protein-ligand complexes with these protein targets, especially HtrA1 to exert anti-rheumatoid arthritis. Further experimental studies show that mechanisms of anti-rheumatoid arthritis effects may also be relevant to inhibit the levels of PGE2, TNF-α, and IL-1β in serum. Therefore, our group can further explore the possible active ingredients and mechanisms of the anti-rheumatoid arthritis effects of flavonoids, and focus on the inhibition of the expression of inflammatory factors and the TGF-β1/Smad signaling pathway associated with HtrA1 protein target receptors, which can provide a direction and powerful reference for the action mechanism and drug research of anti-rheumatoid arthritis of flavonoids in P. orientale.

Ephedra gerardiana aqueous ethanolic extract and fractions attenuate Freund Complete Adjuvant induced arthritis in Sprague Dawley rats by downregulating PGE2, COX2, IL-1β, IL-6, TNF-α, NF-kB and upregulating IL-4 and IL-10

ETHNOPHARMACOLOGICAL RELEVANCE

The whole plant, roots and stems of Ephedra gerardiana (Family Ephedraceae) have long been used as a folk remedy to treat rheumatism and painful joints in Northern Areas of Pakistan.

AIM OF THE STUDY

The purpose of study was to observe the preventive efficacy of Ephedra gerardiana (EG) aerial parts in treating rheumatoid arthritis using Freund's complete adjuvant (FCA) induced arthritis in rat model and to determine its possible mechanism of action.

MATERIAL AND METHODS

Arthritis was induced in Sprague Dawley rats by immunization with 0.1 ml FCA in left footpad. EG aqueous ethanolic extract (30:70) and its aqueous, n-butanol and ethyl acetate fractions at 200 mg/kg were orally administered from day 0, 30 min prior to adjuvant injection and sustained for 28 days. Paw volume/diameter, arthritic score, body weight, and hematological (WBC, RBC, ESR, Hb and Platelet count) and biochemical (AST, ALT, ALP, urea, creatinine, CRP and RF) parameters were observed. The mRNA expression levels of COX-2, IL-1β, IL-6, NF-kB, TNF-α, IL-4 and IL-10 were measured by real time reverse transcription polymerase chain reaction (RT-PCR) while, PGE2 and TNF-α levels in serum samples were measured by Enzyme linked immunosorbent assay (ELISA). Moreover, radiographs of hind paws and histological changes in ankle joint were analyzed in adjuvant injected rats. In addition, anti-oxidant activity of plant extract and fractions was also evaluated using DPPH and reducing power assays. Also, preliminary phytochemistry and total phenolic and flavonoid contents were investigated in most active fraction (aqueous fraction).

RESULTS

EG extract and fractions (notably aqueous fraction) significantly suppressed paw swelling and arthritic score, prevented cachexia and remarkably ameliorated hematological and biochemical changes. Furthermore, the overproduction of PGE2, COX-2, IL-1β, IL-6, NF-kB and TNF-α were remarkably attenuated in all EG treated rats, however, IL-4 and 10 were markedly increased. The radiographic and histopathologic improvement in joint architecture was also observed in EG treated rats. Piroxicam, used as reference drug, also significantly suppressed arthritis. Additionally, plant exhibited notable anti-oxidant activity and phytochemical analysis revealed the presence of alkaloids, flavonoids, phenols, tannins, saponins and glycosides.

CONCLUSION

These results indicate that EG extract and fractions significantly attenuated adjuvant arthritis in rats by decreasing the levels of aforementioned pro-inflammatory and increasing the levels of anti-inflammatory mediators. This suggests that Ephedra gerardiana aerial parts might be used as a therapeutic agent for treating human arthritis.

Micellar solubilisation enhances the antiinflammatory activities of curcumin and boswellic acids in rats with adjuvant-induced arthritis

OBJECTIVE

Native extracts of curcumin and boswellia are known to exert antiinflammatory properties but have poor bioavailability when given orally. Using advanced micellation technology, it has been possible to produce stable solubilisates of these extracts with markedly enhanced bioavailability. In the present study, we compared the chronic antiinflammatory activities of native and micellar curcumin in the rat adjuvant arthritis model, using diclofenac as a reference drug.

METHODS AND PROCEDURES

Adjuvant arthritis was induced by injecting Freund's complete adjuvant (FCA) into the right hind paw of rats and monitoring paw volume over 3 wk. The drugs were given daily for 3 wk, starting from the day of adjuvant inoculation. The serum was collected at end of the experiment for the assay of inflammatory and oxidative stress parameters. Statistical comparisons between different groups were carried out by one-way analysis of variance followed by Tukey-Kramer multiple comparison test.

RESULTS

Solubilized curcumin showed better antiinflammatory activity than its native form. The reduction in paw volume was reflected in corresponding changes in relevant mediators of inflammation like tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), myeloperoxidase (MPO), and lipid peroxidation markers. The combination of curcumin and boswellia solubilisates synergistically produced an even more potent therapeutic effect.

CONCLUSION

The findings confirm that micellar solubilisation of curcumin and boswellia not only increases their bioavailability, but also enhances their biological activity. Micellar curcumin, in particular in combination with micellar boswellia, may thus represent a promising concomitant tool for antiinflammatory treatment and a potential antiinflammatory alternative to synthetic drugs.

Anti-inflammatory Effects of a Small Molecule Gastrin-Releasing Peptide Receptor Antagonist on Adjuvant-Induced Rheumatoid Arthritis in Rats

The anti-inflammatory effects of (R)-2-(1H-Imidazol-1-yl) ethyl-3-(1H-indol-3-yl)-2-(2-p-tolylacetamido)propanamide (RH-1402), a previous designed small molecule Gastrin releasing peptide (GRP) antagonist were evaluated in adjuvant-induced arthritic model of rats, and the inhibitory effect on neutrophil migration induced by GRP was determined by a transwell system experiment in vitro. The arthritis was induced by injection of Complete Freund's Adjuvant (CFA) containing 10 mg/mL of heat killed mycobacterium into the left hind footpad. Experimental rats were randomly divided into 6 groups, including control, placebo, positive control group, RH-1402 of low/middle/high dose group. Disease incidence and severity was evaluated through scoring of the paw edema and histologic features of joint synovial. Blood of all experimental rats was collected for interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) cytokine levels. A transwell system was used to investigate whether RH-1402 would inhibit neutrophils migrating up a gradient of GRP in vitro. RH-1402 (5 and 10 mg/kg) significantly decreased adjuvant induced increased arthritis index during the administration period (days 14-20). Significant inhibition of joint synovial histological features can be found in the RH-1402 treated group, including alleviated Hyperplasia, Inflammatory of infiltration and activation of pannus formation. It also suppressed TNF-α and IL-1β level. Five and 10 mg/kg of RH-1402 significantly inhibited the effect of GRP on neutrophil migration with a dose dependent relationship. These findings indicate that RH-1402 have potential protective anti-inflammatory effects on experimental models of arthritis.

Pain relieving and protective effects of Astragalus hydroalcoholic extract in rat arthritis models

OBJECTIVES

The evaluation of the pharmacological profile of the dried 50% hydroalcoholic extract (50%HA) of Astragali radix in two different animal models of articular damage resembling osteoarthritis and rheumatoid arthritis.

METHODS

Sodium monoiodoacetate (MIA) or complete Freund's adjuvant (CFA) was intra-articular injected (day 0) in the rat tibiotarsal joint to induce damages mimicking osteoarthritis or rheumatoid arthritis. Pain measurements (responses to non-noxious and noxious stimuli, spontaneous pain, articular pain) were assessed on days 7 and 14. On day 14, the tibiotarsal joints were explanted in order to measure the diameter and to assess histological evaluations. Furthermore, the plasmatic concentrations of inflammatory and anti-inflammatory cytokines were measured.

KEY FINDINGS

A single administration of 50%HA (300 mg/kg per os) significantly reduced both MIA-induced pain and CFA-induced pain (78% and 96% pain relief, respectively). The repeated administration prevented the development of hypersensitivity on day 14. The haematoxylin/eosin staining revealed that 50% HA attenuated joint alterations in MIA-injected rats, and furthermore, the joint inflammatory infiltrate was reduced in both models (by about 50%). In CFA-treated rats, 50%HA lowered the plasmatic levels of the pro-inflammatory cytokines interleukin-1β and tumour necrosis factor-α as well as the joint diameter.

CONCLUSIONS

The 50% hydroalcoholic extract of Astragali radix is a valuable candidate for the adjuvant treatment of articular diseases.

The Impacts of Chrysanthemum indicum Extract on Oxidative Stress and Inflammatory Responses in Adjuvant-Induced Arthritic Rats

Chrysanthemum indicum has been used as a therapeutic agent against inflammation, hypertension, and respiratory conditions for many years. This research's aim has been to examine the antioxidant impacts that Chrysanthemum indicum extract (CIE) has on the oxidative stress and inflammatory responses in adjuvant-induced arthritic (AA) rats. 40 rats were categorised into 4 groups according to a completely randomized approach: Group I involved normal control rats (CTRL) that received a basal diet; Group II involved arthritic control rats (CTRL-AA) that received the same diet; Group III involved rats that received a basal diet and 30 mg/kg CIE; and Group IV involved arthritic rats with the same diet as Group III rats (CIE-AA). After injection with complete Freund's adjuvant, body weight, arthritis score, and the serum levels of TNF-α, IL-1β, IL-6, myeloperoxidase (MPO), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were assessed. The results demonstrated that CIE delayed the onset time of arthritis and decreased the clinical arthritis severity score (P < 0.05). Observations of CIE-AA and CTRL-AA rats demonstrated that CIE alleviates oxidative stress and inflammatory responses in CIE-AA group. In conclusion, CIE alleviated oxidative stress and inflammatory responses, thereby highlighting its potential use as a candidate for clinical treatments of rheumatoid arthritis.

Xitong Wan attenuates inflammation development through inhibiting the activation of nuclear factor-κB in rats with adjuvant-induced arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Xitong Wan (XTW), a traditional Chinese herbs formula, has been used to treat "Bi Zheng" in the clinical practice of traditional Chinese medicine (TCM) for hundreds of years. However, no scientific validation is available on the anti-rheumatic effect of XTW.

AIM OF STUDY

This study was carried out to investigate the effects of XTW on joints swelling, joints destruction, production of inflammatory mediators and nuclear factor-κB (NF-κB) activation in rats with adjuvant-induced arthritis (AIA).

MATERIALS AND METHODS

AIA was induced by intradermal injection of Complete Freund's adjuvant in the footpad of Wistar rats. Paw volume was measured every 7 days during XTW treatment. Histological score was calculated by hematoxylin and eosin staining. Osteoclast number in articular tissues was counted by tartrate-resistant acid phosphatase staining. Levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in serum were detected by enzyme-linked immunosorbent assay. Levels of NF-κBp65 and inhibitor of NF-κB (IκB)α in synovium were analyzed by Western blot assay.

RESULTS

Compared with AIA group rats, XTW significantly decreased the paw volume of AIA rats. Meanwhile, XTW significantly reduced the histological score and osteoclast number in articular tissues of AIA rats. In addition, XTW markedly abated the levels of TNF-α, IL-1β and IL-6 in serum, as well as enhanced the level of IκBα in synovium of AIA rats. However, XTW did not show significant effect on the level of p65 in synovium of AIA rats.

CONCLUSIONS

These results suggest that XTW attenuates the inflammation development through inhibiting the NF-κB-mediated proinflammatory cytokines production in AIA rats. Our study provides the scientific evidence of XTW on treatment of rheumatoid arthritis in the clinical practice of TCM.

Acute effect of Capparis spinosa root extracts on rat articular pain

ETHNOPHARMACOLOGICAL RELEVANCE

Capparis spinosa L. originates from dry regions of Asia and Mediterranean basin. In traditional medicine of these areas, infusions from caper root are considered to be beneficial for the treatment of rheumatism, gout and against abdominal pains.

AIM OF THE STUDY

To evaluate the pain relieving properties of a Syrian cultivar of Capparis spinosa roots in rat models of osteoarthritis and rheumatoid arthritis.

MATERIALS AND METHODS

Decoction (DEC) and hydroalcoholic extract (EtH₂O) were obtained from powdered roots; the latter was further separated in CH₂Cl₂ and aqueous (H₂O-Res) fractions. The extracts were characterized in terms of spermidine alkaloids by HPLC/DAD/MS and stachydrine by NMR. Different amount of free and glycosilated forms of capparispine and analogues (from 0.5% w/w for DEC up to 7.6% w/w for CH₂Cl₂ fraction) were detected. Rat models of rheumatoid arthritis and osteoarthritis were induced by the intra-articular administration of Complete Freund's Adjuvant (CFA) or monosodium iodoacetate (MIA), respectively.

RESULTS

Fourteenth days after CFA or MIA injection, the different preparations of Capparis spinosa (3, 30, 100 and 300mgkg^-1) were acutely administered p.o.. Powdered roots (300mgkg^-1), DEC (100mgkg^-1), and EtH₂O (300mgkg^-1) significantly reduced hypersensitivity to mechanical noxious stimuli as well as spontaneous pain evaluated as hind limb bearing alterations in both models. The CH₂Cl₂ and the H₂O-Res (30mgkg^-1) were the most potent in reverting pain threshold alterations despite the different content of free alkaloids.

CONCLUSIONS

Capparis spinosa extracts relieved pain related to rheumatoid arthritis and osteoarthritis after single administration. A synergistic effect due to a specific "phytochemical mixture" is suggested.

Effects of the neutrophil elastase inhibitor EL-17 in rat adjuvant-induced arthritis

OBJECTIVES

Neutrophil elastase (NE), a granule-associated enzyme, participates in connective tissue breakdown and promotes cytokine release and specific receptor activation during various inflammatory diseases like RA. NE is increased in the SF and cartilage of RA patients and represents a target for the development of new therapeutic possibilities. The present research aimed to evaluate the preclinical pharmacological profile of the N-benzoylpyrazole derivative EL-17, a potent and selective NE inhibitor, in a rat model of RA.

METHODS

Complete Freund's Adjuvant (CFA) was injected in the tibiotarsal joint and the effect of acute or repeated treatments with EL-17 (1-30 mg/kg by mouth) were evaluated.

RESULTS

On day 14 after CFA injection, a single administration of EL-17 significantly reduced CFA-dependent hypersensitivity to mechanical noxious stimuli and the postural unbalance related to spontaneous pain. To evaluate the preventive efficacy, EL-17 was administered daily starting from the day of CFA treatment. Behavioural measurements performed on days 7 and 14 showed a progressive efficacy of EL-17 against hypersensitivity to mechanical noxious and non-noxious stimuli, as well as a decrease of hind limb weight-bearing alterations. Histological evaluation of the tibiotarsal joint (day 14) demonstrated significant prevention of articular derangement after EL-17 (30 mg/kg) treatment. The protective effects of EL-17 directly correlated with a complete reversion of the plasma NE activity increase induced by CFA.

CONCLUSIONS

The NE inhibitor EL-17 relieved articular pain after acute administration. Furthermore, repeated treatment reduced the development of hypersensitivity and protected joint tissue, revealing a disease-modifying profile.

The Evaluation of the Therapeutic Efficacy and Side Effects of a Macromolecular Dexamethasone Prodrug in the Collagen-Induced Arthritis Mouse Model

PURPOSE

To investigate the efficacy and safety of N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-dexamethasone conjugate (P-Dex) in the collagen-induced arthritis (CIA) mouse model.

METHODS

HPMA copolymer labeled with a near infrared fluorescence (NIRF) dye was administered to mice with CIA to validate its passive targeting to inflamed joints and utility as a drug carrier system. The CIA mice were treated with P-Dex, dexamethasone (Dex) or saline and the therapeutic efficacy and skeletal toxicity evaluated using clinical scoring and micro-computed tomography (μ-CT).

RESULTS

The NIRF signal of the HPMA copolymer localized to arthritic joints consistent with its passive targeting to sites of inflammation. While the CIA mice responded more rapidly to P-Dex compared to Dex, the final clinical score and endpoint μ-CT analyses of localized bone erosions indicated that both single dose P-Dex and dose equivalent daily Dex led to comparable clinical efficacy after 30 days. μ-CT analysis of the proximal tibial metaphyses showed that P-Dex treatment was associated with significantly higher BMD and BV/TV compared to Dex and the saline control, consistent with reduced glucocorticoid (GC) skeletal toxicity.

CONCLUSION

These results validate the therapeutic efficacy of P-Dex in the CIA mouse model. P-Dex treatment averted the adverse effects of GC's on systemic bone loss, supporting its utility in clinical development for the management of rheumatoid arthritis.

Mouse Models of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic debilitating autoimmune disorder characterized by synovitis that leads to cartilage and bone erosion by invading fibrovascular tissue. Mouse models of RA recapitulate many features of the human disease. Despite the availability of medicines that are highly effective in many patient populations, autoimmune diseases (including RA) remain an area of active biomedical research, and consequently mouse models of RA are still extensively used for mechanistic studies and validation of therapeutic targets. This review aims to integrate morphologic features with model biology and cover the key characteristics of the most commonly used induced and spontaneous mouse models of RA. Induced models emphasized in this review include collagen-induced arthritis and antibody-induced arthritis. Collagen-induced arthritis is an example of an active immunization strategy, whereas antibody- induced arthritis models, such as collagen antibody–induced arthritis and K/BxN antibody transfer arthritis, represent examples of passive immunization strategies. The coverage of spontaneous models in this review is focused on the TNFΔ ARE mouse, in which arthritis results from overexpression of TNF-α, a master proinflammatory cytokine that drives disease in many patients.

Therapeutic effects of the superoxide dismutase mimetic compound MnIIMe2DO2A on experimental articular pain in rats

Superoxide anion (O₂  ^•−) is overproduced in joint inflammation, rheumatoid arthritis, and osteoarthritis. Increased O₂  ^•− production leads to tissue damage, articular degeneration, and pain. In these conditions, the physiological defense against O₂  ^•−, superoxide dismutases (SOD) are decreased. The Mn^II complex MnL4 is a potent SOD mimetic, and in this study it was tested in inflammatory and osteoarticular rat pain models. In vivo protocols were approved by the animal Ethical Committee of the University of Florence. Pain was measured by paw pressure and hind limb weight bearing alterations tests. MnL4 (15 mg kg⁻¹) acutely administered, significantly reduced pain induced by carrageenan, complete Freund's adjuvant (CFA), and sodium monoiodoacetate (MIA). In CFA and MIA protocols, it ameliorated the alteration of postural equilibrium. When administered by osmotic pump in the MIA osteoarthritis, MnL4 reduced pain, articular derangement, plasma TNF alpha levels, and protein carbonylation. The scaffold ring was ineffective. MnL4 (10⁻⁷ M) prevented the lipid peroxidation of isolated human chondrocytes when O₂  ^•− was produced by RAW 264.7. MnL4 behaves as a potent pain reliever in acute inflammatory and chronic articular pain, being its efficacy related to antioxidant property. Therefore MnL4 appears as a novel protective compound potentially suitable for the treatment of joint diseases.

Protective effect of RC-3095, an antagonist of the gastrin-releasing peptide receptor, in experimental arthritis

OBJECTIVE

To evaluate the antiinflammatory effects of RC-3095 in 2 experimental models of arthritis, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA), and to determine the mechanisms of action involved.

METHODS

RC-3095 was administered daily to mice with CIA and mice with AIA, after induction of disease with methylated bovine serum albumin. Disease incidence and severity were assessed using a clinical index and evaluation of histologic features, respectively. In mice with CIA, gastrin-releasing peptide receptor (GRPR) was detected by immunohistochemical analysis, while in mice with AIA, migration of neutrophils, presence of glycosaminoglycans, and lymphocyte proliferation, determined using the MTT assay, were assessed. Expression of cytokines interleukin-17 (IL-17), IL-1β, and tumor necrosis factor α (TNFα) was evaluated in all mouse knees using enzyme-linked immunosorbent assay. Treg cell production was assessed by flow cytometry in the joints of mice with AIA.

RESULTS

In mice with AIA, administration of RC-3095 reduced neutrophil migration, mechanical hypernociception, and proteoglycan loss. These findings were associated with inhibition of the levels of all 3 proinflammatory cytokines, decreased lymphocyte proliferation, and increased Treg cell numbers. In the CIA model, treatment with RC-3095 led to a significant reduction in arthritis clinical scores and the severity of disease determined histologically. Synovial inflammation, synovial hyperplasia, pannus formation, and extensive erosive changes were all dramatically reduced in the arthritic mice treated with RC-3095. Furthermore, arthritic mice treated with RC-3095 showed a significant reduction in the concentrations of IL-17, IL-1β, and TNFα, and showed a diminished expression of GRPR.

CONCLUSION

These findings suggest that the GRP pathway has a significant role in chronic arthritis, and its inhibition can be explored as a possible therapeutic strategy in rheumatoid arthritis.

Human adjuvant disease induced by foreign substances: a new model of ASIA (Shoenfeld's syndrome)

OBJECTIVE

To investigate the clinical, laboratory and histological manifestations of patients who received illegal injections of foreign substances for cosmetic purposes.

PATIENTS AND METHODS

We studied patients who met the following inclusion criteria: 1) history of application of foreign substances for cosmetic purposes, 2) clinical data of autoimmune disease or non-specific autoimmune manifestation (i.e. arthralgias, myalgia, malaise, fever, and weight loss), 3) detection of autoantibodies in patients' sera, 4) histological evidence of chronic inflammation and/or granulomatous reaction to foreign body.

RESULTS

Fifty female patients aged 44.4 ± 10 years were studied. The mean time between application of foreign substances and onset of symptoms was 4.5 ± 4.3 years. Patients were followed for 12 ± 7.5 years. Forty-one patients were injected with mineral oil, nine patients received other substances: three iodine gadital, one guayacol, one guayacol plus silicone fluid, two collagen, two silicone fluid. The sites of application were: buttocks (36), legs and/or thighs (11), breasts (eight) hands and face (one), face (two) (seven patients received an injection to more than one site). Thirty patients presented with non-specific autoimmune manifestations, whereas 20 patients fulfilled the criteria for a defined autoimmune disease such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, overlap syndrome, autoimmune hemolytic anemia, autoimmune thyroiditis, autoimmune hepatitis, and ulcerative colitis.

CONCLUSIONS

Cases of human adjuvant disease following illegal injections of oil substances for cosmetic purposes are reported. Patients presented with defined autoimmune diseases as well as with non-specific autoimmune manifestations. Illegal injection of these substances could lead to serious local and systemic complications, even to death. These cases represent another model of Autoimmune/inflammatory Syndrome Induced by Adjuvants (ASIA). The use of these substances should be prohibited.

A high molecular weight protein extract of Mastobranchus indicus (Mi-64) having antiarthritic activity in experimental animals

Mi-64, a high molecular weight protein (130 kDa), obtained from the tissue homogenate of marine polychaete (Mastobranchus indicus) collected from the Indian Sunderban has antiarthritic activity in experimental animals. The FCA-induced arthritis model was developed in Wistar albino rats to evaluate the antiarthritic effects of Mi-64. After FCA induction, the rats were treated with Mi-64 (0.25 and 0.5 mg kg(-1) body weight) for 10 days. We have determined the paw/ankle swellings, urinary hydroxyproline and glucosamine, serum acid and alkaline phosphatases to assess the antiarthritic activity. The levels of interleukin-1 beta (IL-1β), IL-6, cytokine-induced neutrophil chemoattractant-1 (CINC-1), tumor necrosis factor-alpha (TNF-α), and IL-10 were measured by ELISA. Results showed that Mi-64 significantly reduced paw/ankle swellings and restored the urinary hydroxyproline/glucosamine and serum phosphatases. Mi-64 significantly inhibited the overproduction of IL-1β, IL-6, CINC-1, and TNF-α and augmented IL-10 production. The data suggest that Mi-64 produced significant antiarthritic effects that may be mediated by balancing the pro- and anti-inflammatory cytokines.

Effect of cocoa-enriched diets on lymphocytes involved in adjuvant arthritis in rats

Cocoa and its flavonoids have potential anti-inflammatory properties in vitro and in acute inflammation models in vivo. The aim of the present study was to ascertain the effects of two cocoa-enriched diets on adjuvant arthritis (AA) in rats, considering not only clinical and biochemical inflammatory indices, but also antibody response and lymphocyte composition. Female Wistar rats were fed with a 5 or 10 % cocoa-enriched diet beginning 2 weeks before arthritis induction and until the end of the study. AA was induced by an intradermal injection of heat-killed Mycobacterium butyricum suspension. The hind-paw swelling (plethysmometry), serum anti-mycobacterial antibody concentration (ELISA), blood and inguinal lymph node lymphocyte subset percentage (flow cytometry), and IL-2, interferon γ and PGE₂ released from splenocytes (ELISA) were assessed. Although the cocoa diets had no significant effect on hind-paw swelling, a tendency to reduce it was observed at the end of the study. Cocoa-enriched diets were able to decrease the serum anti-mycobacterial antibody concentration and the splenocyte PGE2 production, as well as the proportion of T-helper (Th) lymphocytes in blood and regional lymph nodes, which probably includes cells responsible for the arthritic process. The cocoa diets prevented a decrease in the proportion of regulatory T-cells in blood and a disequilibrium between inguinal lymph node natural killer (NK) CD8⁺ and NK CD8⁻ subsets. In conclusion, the cocoa-enriched diets during AA were not able to significantly decrease joint inflammation but modified Th-cell proportions and prevented specific antibody synthesis.

Prevention of the progression of adjuvant induced arthritis by oral supplementation of Indian fresh water mussel (Lamellidens marginalis) aqueous extract in experimental rats

AIM OF THIS STUDY

Mussel is well accepted as food all over India. Beside for its nutritive value, people residing in Kosi river basin, Bihar, India, consume a preparation of soup, made from the footpad of molluscan species, with the belief that it gives relief from signs and symptoms of joint pain and related problems. This study was designed to explore the preventive activity of Indian fresh water mussel (Lamellidens marginalis) aqueous extract oral supplementation in experimental arthritis model.

MATERIALS AND METHODS

Arthritis was induced in male albino rats by intradermal injection of Freund's complete adjuvant in right hind footpad. Lamellidens marginalis extract (LME1, 500 mg/kg/day and LME2, 1 g/kg/day) peroral supplementation started from the 1st day after adjuvant injection and was continued for the subsequent 13 days. Severity of arthritis was evaluated from paw diameter, ankle diameter, paw weight, urinary hydroxyproline, glucosamine level, serum interleukin-1β, IL6, IL10, CINC1, TNFα level, lysosomal enzyme levels and from histopathological assessment.

RESULTS

Lamellidens marginalis extract supplementation significantly (p<0.05) decreased paw diameter, ankle diameter, and paw weight in treated groups (LME1, 500 mg/kg/day and LME2, 1 g/kg/day) as compared with arthritic group. Urinary hydroxyproline, glucosamine level, serum IL1β, IL6, CINC1, TNFα, IL10 and lysosomal enzyme levels were restored significantly (p<0.05) in treated groups (LME1, 500 mg/kg/day and LME2, 1 g/kg/day) as compared to arthritic group. Synovial membrane damage and neutrophil infiltration in histopathological examination was restored significantly by LME supplementation as compared to arthritic group.

CONCLUSIONS

Thus, it might be concluded that experimental animals supplemented with Lamellidens marginalis extract were protected against the severity of disease progression in adjuvant induced arthritis.

Utility of animal models for identification of potential therapeutics for rheumatoid arthritis

Animal models of rheumatoid arthritis (RA) are widely used for testing potential new therapies for RA. However, the question of which animal model is most predictive of therapeutic efficacy in human RA commonly arises in data evaluation. A retrospective review of the animal models used to evaluate approved, pending RA therapies, and compounds that were discontinued during phase II or III clinical trials found that the three most commonly used models were adjuvant-induced arthritis (AIA) in rats and collagen-induced arthritis (CIA) in rats and mice. Limited data were found for more recently developed genetically modified animal models. Examination of the efficacy of various compounds in these animal models revealed that a compound's therapeutic efficacy, rather than prophylactic efficacy, in AIA and CIA models was more predictive of clinical efficacy in human RA than data from either model alone.

Subcutaneous inflammation (panniculitis) in tibio-tarsal joint of rats inoculated with complete Freund's adjuvant

Complete Freund's adjuvant (CFA)-induced arthritis in rats, which presents similar features to rheumatoid arthritis, is a model widely used in aetiopathogenetic and investigational drug studies. In this model, arthritis is induced by intradermal injection of Mycobacterium tuberculosis suspended in mineral oil in the hind footpad. Although the histopathology findings in the joint are well described, the marked subcutaneous features of panniculitis that concomitantly occur in this model have received no attention. The objective of this paper is to describe the subcutaneous histopathological features in 8 Wistar rats after intraplantar injection of CFA. We studied the subcutaneous histopathological features in 8 Wistar rats after intraplantar injection of CFA in the left hind paw. The levels of subcutaneous inflammation of the animals in this study were evaluated for the histological characteristics present in the tissue and scored with 4 parameters (acute inflammation, chronic inflammation with fibrosis, subcutaneous and profound soft tissue necrosis, and the presence of giant cells, neutrophils, macrophages and lymphocytes) on days 4, 7, 11 and 15 after induction. All animals developed intense subcutaneous inflammation characteristic of panniculitis, with predominance of acute changes in the initial period, with progression to a self-perpetuating chronic fibrotic process on day 15. These observations precede the joint changes. Besides being an interesting model for better studying diseases with panniculitis, our observations bring up issues concerning the possible relations between subcutaneous and joint inflammatory changes.

Freund's complete adjuvant induces arthritis in mice lacking a functional interferon-gamma receptor by triggering tumor necrosis factor alpha-driven osteoclastogenesis

OBJECTIVE

To investigate the hypothesis that Freund's complete adjuvant (CFA) plays an essential role in the induction of collagen-induced arthritis in mice, by testing whether CFA by itself is able to induce arthritis in interferon-gamma receptor-knockout (IFNgammaR-KO) mice.

METHODS

IFNgammaR-KO and wild-type mice were sensitized with a single intradermal injection of CFA containing heat-killed Mycobacterium butyricum. Flow cytometric analysis and in vitro osteoclastogenesis assays were performed on blood, spleen, and bone marrow cells. Tumor necrosis factor (TNF) levels were measured in the serum, and levels of RANKL, osteoprotegerin (OPG), and TNFalpha in the synovium were determined by quantitative reverse transcriptase-polymerase chain reaction. Effects of treatment with the TNFalpha antagonist etanercept were assessed.

RESULTS

Symptoms of arthritis appeared in IFNgammaR-KO mice but not in wild-type mice, and reached an incidence of 55%. The onset coincided with an expansion of CD11b+ splenocytes that spontaneously produced TNFalpha and with increased osteoclastogenesis in spleen and blood cells. Expansion of CD11b+ splenocytes and osteoclast precursor cells was more pronounced in arthritic than in nonarthritic mice. There was a >100-fold increase in the RANKL:OPG ratio in the synovia of CFA-sensitized mice compared with those of naive animals. Treatment with etanercept prevented the development of arthritis and mitigated the increased expansion of myeloid cells as well as the increase in osteoclast precursor numbers in the spleen and blood.

CONCLUSION

These results indicate that sensitization of mice with CFA creates a condition in which dysregulation of a single cytokine leads to arthritis by triggering TNFalpha-driven osteoclastogenesis.

Anti-inflammatory effects of 4-phenyl-3-butenoic acid and 5-(acetylamino)-4-oxo-6-phenyl-2-hexenoic acid methyl ester, potential inhibitors of neuropeptide bioactivation

Substance P (SP) and calcitonin gene-related peptide (CGRP) are well established mediators of inflammation. Therefore, inhibition of the biosynthesis of these neuropeptides is an attractive potential strategy for pharmacological intervention against a number of inflammatory diseases. The final step in the biosynthesis of SP and CGRP is the conversion of their glycine-extended precursors to the active amidated peptide, and this process is catalyzed by sequential action of the enzymes peptidylglycine alpha-monooxygenase (PAM) and peptidylamidoglycolate lyase. We have demonstrated previously that 4-phenyl-3-butenoic acid (PBA) is a PAM inhibitor, and we have also shown that in vivo inhibition of serum PAM by PBA correlates with this compound's ability to inhibit carrageenan-induced edema in the rat. Here we demonstrate the ability of PBA to inhibit all three phases of adjuvant-induced polyarthritis (AIP) in rats; this represents the first time that an amidation inhibitor has been shown to be active in a model of chronic inflammation. We recently introduced 5-(acetylamino)-4-oxo-6-phenyl-2-hexenoic acid (AOPHA) as one of a new series of mechanism-based amidation inhibitors. We now report for the first time that AOPHA and its methyl ester (AOPHA-Me) are active inhibitors of serum PAM in vivo, and we show that AOPHA-Me correspondingly inhibits carrageenan-induced edema in rats in a dose-dependent manner. Neither PBA nor AOPHA-Me exhibits significant cyclooxygenase (COX) inhibition in vitro; thus, the anti-inflammatory activities of PBA and AOPHA-Me are apparently not a consequence of COX inhibition. We discuss possible pharmacological mechanisms that may account for the activities of these new anti-inflammatory compounds.

Heat shock proteins in autoimmune diseases

Heat shock proteins (hsp's) are among the most conserved proteins in evolution. They have been identified as important pathogen-related antigens as well as autoantigens suitable for construction of novel vaccines. The high evolutionary homology of hsp's has raised the question about the safety of such vaccines. Experimental and clinical observations have confirmed that hsp proteins are involved in the regulation of some autoimmune disease such as autoimmune arthritis, type 1 diabetes mellitus, atherosclerosis, multiple sclerosis, and other autoimmune reactions. It has been shown in experimental animals that some hsp proteins (especially hsp60, hsp70, and hsp10) can either induce or prevent autoimmune reactions depending on the circumstances. This article discusses the involvement of hsp proteins in the etiology of autoimmune diseases and it presents promising experimental data on the effects of immunization with hsp proteins in the prevention and therapy of autoimmune diseases.

Commensal bacteria (normal microflora), mucosal immunity and chronic inflammatory and autoimmune diseases

Commensal microflora (normal microflora, indigenous microbiota) consists of those micro-organisms, which are present on body surfaces covered by epithelial cells and are exposed to the external environment (gastrointestinal and respiratory tract, vagina, skin, etc.). The number of bacteria colonising mucosal and skin surfaces exceeds the number of cells forming human body. Commensal bacteria co-evolved with their hosts, however, under specific conditions they are able to overcome protective host responses and exert pathologic effects. Resident bacteria form complex ecosystems, whose diversity is enormous. The most abundant microflora is present in the distal parts of the gut; the majority of the intestinal bacteria are Gram-negative anaerobes. More than 50% of intestinal bacteria cannot be cultured by conventional microbiological techniques. Molecular biological methods help in analysing the structural and functional complexity of the microflora and in identifying its components. Resident microflora contains a number of components able to activate innate and adaptive immunity. Unlimited immune activation in response to signals from commensal bacteria could pose the risk of inflammation; immune responses to mucosal microbiota therefore require a precise regulatory control. The mucosal immune system has developed specialised regulatory, anti-inflammatory mechanisms for eliminating or tolerating non-dangerous, food and airborne antigens and commensal micro-organisms (oral, mucosal tolerance). However, at the same time the mucosal immune system must provide local defense mechanisms against environmental threats (e.g. invading pathogens). This important requirement is fulfilled by several mechanisms of mucosal immunity: strongly developed innate defense mechanisms ensuring appropriate function of the mucosal barrier, existence of unique types of lymphocytes and their products, transport of polymeric immunoglobulins through epithelial cells into secretions (sIgA) and migration and homing of cells originating from the mucosal organised tissues in mucosae and exocrine glands. The important role of commensal bacteria in development of optimally functioning mucosal immune system was demonstrated in germ-free animals (using gnotobiological techniques). Involvement of commensal microflora and its components with strong immunoactivating properties (e.g. LPS, peptidoglycans, superantigens, bacterial DNA, Hsp) in etiopathogenetic mechanism of various complex, multifactorial and multigenic diseases, including inflammatory bowel diseases, periodontal disease, rheumatoid arthritis, atherosclerosis, allergy, multiorgan failure, colon cancer has been recently suggested. Animal models of human diseases reared in defined gnotobiotic conditions are helping to elucidate the aetiology of these frequent disorders. An improved understanding of commensal bacteria-host interactions employing germ-free animal models with selective colonisation strategies combined with modern molecular techniques could bring new insights into the mechanisms of mucosal immunity and also into pathogenetic mechanisms of several infectious, inflammatory, autoimmune and neoplastic diseases. Regulation of microflora composition (e.g. by probiotics and prebiotics) offers the possibility to influence the development of mucosal and systemic immunity but it can play a role also in prevention and treatment of some diseases.

The utility of pathway selective estrogen receptor ligands that inhibit nuclear factor-kappa B transcriptional activity in models of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease that produces synovial proliferation and joint erosions. The pathologic lesions of RA are driven through the production of inflammatory mediators in the synovium mediated, in part, by the transcription factor NF-κB. We have identified a non-steroidal estrogen receptor ligand, WAY-169916, that selectively inhibits NF-κB transcriptional activity but is devoid of conventional estrogenic activity. The activity of WAY-169916 was monitored in two models of arthritis, the HLA-B27 transgenic rat and the Lewis rat adjuvant-induced model, after daily oral administration. In both models, a near complete reversal in hindpaw scores was observed as well as marked improvements in the histological scores. In the Lewis rat adjuvant model, WAY-169916 markedly suppresses the adjuvant induction of three serum acute phase proteins: haptoglobin, α1-acid glycoprotein (α1-AGP), and C-reactive protein (CRP). Gene expression experiments also demonstrate a global suppression of adjuvant-induced gene expression in the spleen, liver, and popliteal lymph nodes. Finally, WAY-169916 was effective in suppressing tumor necrosis factor-α-mediated inflammatory gene expression in fibroblast-like synoviocytes isolated from patients with RA. Together, these data suggest the utility of WAY-169916, and other compounds in its class, in treating RA through global suppression of inflammation via selective blockade of NF-κB transcriptional activity.

Immunonutrition and cancer

The immune system is the body's primary defence against invading pathogens, non-self components and cancer cells. Inflammatory processes, including the release of pro-inflammatory cytokines and formation of reactive oxygen and nitrogen species, are an essential part of these processes. Although such actions are usually followed rapidly by anti-inflammatory effects, excessive production of pro-inflammatory cytokines, or their production in the wrong biological context may lead to situations of chronic inflammation. Whether such conditions arise as a result of exogenous chemicals, invading pathogens or disease processes, the long-term implications include an increased risk of cancer. A number of nutrients have the ability to modulate immune response and counter inflammatory processes. Zinc, epigallocatechin galate (EGCG), omega-3 polyunsaturated fatty acids and probiotics all act differently to modulate immune response, but all appear to have the potential to protect against cancer development and progression. We suggest that immunonutrition may provide a less invasive alternative to immunotherapy in protection against cancers associated with chronic inflammation.

The T cells specific for the carboxyl-terminal determinants of self (rat) heat-shock protein 65 escape tolerance induction and are involved in regulation of autoimmune arthritis

Immunization of Lewis rats with heat-killed Mycobacterium tuberculosis H37Ra leads to development of polyarthritis (adjuvant-induced arthritis; AA) that shares several features with human rheumatoid arthritis (RA). Immune response to the 65-kDa mycobacterial heat-shock protein (Bhsp65) is believed to be involved in induction of AA as well as in experimental modulation of this disease. However, the understanding of several critical aspects of the pathogenesis of AA in the Lewis rat has severely been hampered by the lack of information both regarding the level as well as epitope specificity of tolerance to the mammalian self (rat) homologue of Bhsp65, 65-kDa rat heat-shock protein (Rhsp65), and about the functional attributes of the T cell repertoire specific for this self protein. In this study, we established that tolerance to Rhsp65 in the Lewis rat is incomplete, and that the residual T cells primed upon challenge with this self hsp65 are disease regulating in nature. We also have defined the T cell epitopes in the C-terminal region within Rhsp65 that contribute predominantly to the immune reactivity as well as the AA-protective effect of this self protein. Furthermore, the T cells primed by peptides comprising these C-terminal determinants can be efficiently restimulated by the naturally generated epitopes from endogenous Rhsp65, suggesting that self hsp65 might also be involved in natural remission from acute AA. These novel first experimental insights into the self hsp65-directed regulatory T cell repertoire in AA would help develop better immunotherapeutic approaches for autoimmune arthritis.

Suppressive oligonucleotides protect against collagen-induced arthritis in mice

OBJECTIVE

To examine whether systemic administration of oligonucleotides (ODNs), known to inhibit the production of proinflammatory cytokines, alters host susceptibility to collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA).

METHODS

CIA was induced by injecting DBA/1 mice with type II collagen (CII) in Freund's complete adjuvant, followed 3 weeks later by CII in Freund's incomplete adjuvant. The effect of suppressive ODNs on the incidence and severity of disease was monitored, as were immune correlates of CIA.

RESULTS

Suppressive ODNs administered during the inductive phase of CIA significantly reduced the incidence and severity of arthritis. Treatment with suppressive ODNs significantly decreased serum titers of pathogenic IgG anti-CII autoantibodies and interferon-gamma production by collagen-reactive T cells.

CONCLUSION

Suppressive ODNs may be of therapeutic value in the treatment of RA, and potentially other autoimmune diseases.