Alteration of interleukin-1 activity and the acute phase response in adjuvant arthritic rats treated with disease modifying antirheumatic drugs

Anti-malarial Drugs are Not Created Equal for SARS-CoV-2 Treatment: A Computational Analysis Evidence

BACKGROUND

The evolution of the pandemic has burdened the national healthcare systems worldwide and at present, there is no preferred antiviral treatment for COVID-19. Recently, the SARS-Cov-2 protease structure was released that may be exploited in in-silico studies in order to conduct molecular docking analysis.

METHODS

In particular, we compared the binding of twoantimalarial drugs, already in use, (i.e. chloroquine and hydroxychloroquine), which showed some potential clinical effects on COVID-19 patients, using ritonavir, lopinavir and darunavir as positive control tree antiviral recognized compounds.

RESULTS

Our results showed that hydroxychloroquine but not chloroquine exhibited a significant binding activity to the main protease similar to that possessed by protease inhibitors tested for other viral infections.

CONCLUSION

Our data suggest that hydroxychloroquine may exert additional direct antiviral activity compared to chloroquine. In the absence of clinical studies comparing the efficacy of these two compounds, hydroxychloroquine may offer additional effects and may be considered as the first choice.

G6PD deficiency, redox homeostasis, and viral infections: implications for SARS-CoV-2 (COVID-19)

The COVID-19 pandemic has so far affected more than 45 million people and has caused over 1 million deaths worldwide. Infection with SARS-CoV-2, the pathogenic agent, which is associated with an imbalanced redox status, causes hyperinflammation and a cytokine storm, leading to cell death. Glucose-6-phosphate dehydrogenase (G6PD) deficient individuals may experience a hemolytic crisis after being exposed to oxidants or infection. Individuals with G6PD deficiency are more susceptible to coronavirus infection than individuals with normally functioning G6PD. An altered immune response to viral infections is found in individuals with G6PD deficiency. Evidence indicates that G6PD deficiency is a predisposing factor of COVID-19.

COVID-19: Older drugs for a novel disease-Chloroquine, hydroxychloroquine, and possible Pentoxifylline-set to start the second innings?

Currently no drug is approved for the prophylaxis and management of COVID 19. Lots of activities on vaccine and trials with drugs are underway. Some evidence have shown positive results using older established drug in the management of severe cases. We are also of same view and opinion to adopt some emergency measure by pharmacological intervention till a newer drug available in the market.

Of chloroquine and COVID-19

Recent publications have brought attention to the possible benefit of chloroquine, a broadly used antimalarial drug, in the treatment of patients infected by the novel emerged coronavirus (SARS-CoV-2). The scientific community should consider this information in light of previous experiments with chloroquine in the field of antiviral research.

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In vitro data suggest that chloroquine inhibits SARS Cov-2 replication.

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In past research, chloroquine has shown in vitro activity against many different viruses, but no benefit in animal models.

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Chloroquine has been proposed several times for the treatment of acute viral diseases in humans without success.

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The outcomes of some current clinical trials of chloroquine in China have been announced, without access to the data.

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Peer review of the results and an independent assessment of the potential benefit for patients are essential.

Amelioration of adjuvant induced arthritis in Sprague Dawley rats through modulation of inflammatory mediators by Ribes alpestre Decne

ETHNOPHARMACOLOGICAL RELEVANCE

Ribes alpestre Decne has been commonly used in the treatment of joint complaints.

AIM OF STUDY

The present study was undertaken to evaluate the antiarthritic potential of ethanolic extract and fractions of Ribes alpestre and to explore its probable mechanism of action.

MATERIAL AND METHODS

Complete Freunds adjuvant induced arthritis in Sprague Dawley rats was used to assess antiarthritic activity of aqueous ethanol extract, butanol and aqueous fractions at 200 mg/kg oral dose for 28 days. Paw volume and diameter, arthritic index, body weight, hematological and biochemical parameters, radiographic and histological analysis of ankle joints were carried out. An array of pro-inflammatory mediators (IL-1β, IL-6, NF-Kβ, TNF-α, COX-2, IL-4, IL-10 and PGE2) were estimated by RT-PCR and enzyme linked immunosorbent assay. Antioxidant capacity was assessed using DPPH and reducing power assays. Qualitative phytochemical screening, total phenolic and flavonoid content and HPLC analysis of aqueous fraction of Ribes alpestre were also carried out.

RESULTS

Significant (p < 0.001) reduction in paw volume and thickness and arthritic score by aqueous ethanolic extract and its fractions has been found. Aqueous ethanolic extract and fractions in particular aqueous fraction considerably prevented decrease in body weight, alterations in hematological parameters. Radiographic and histological examination revealed no significant architectural changes in joints of treated rats. Significant (p < 0.05-0.001) down regulation of pro-inflammatory genes IL-1β, TNF-α, IL-6, COX-2, PGE2 and NF-Kβ alongwith noteworthy increase in levels of IL-4 and IL-10 was recorded among treated animals. Aqueous ethanol extract and its fractions demonstrated notable and concentration dependent (50-6400 μg/ml) antioxidant potential. Qualitative phytochemical analysis of active fraction (aqueous) displayed presence of flavonoids, alkaloids, tannins and glycosides. Besides total phenolic and flavonoid contents has been found to be 179.3 mg GAE/ml and 389.40 μg QE/ml in aqueous fraction of Ribes alpestre respectively. HPLC profile demonstrated presence of quercitin, chlorogenic acid, vanillic acid and cinamic acid in aqueous fraction.

CONCLUSION

Present communication suggests Ribes alpestre a potent antiarthritic therapy by ameliorating adjuvant arthritis in rats by downregulating proinflammatory mediators with up regulation of anti-inflammatory cytokines.

Paradoxical Effect of Chloroquine Treatment in Enhancing Chikungunya Virus Infection

Since 2005, Chikungunya virus (CHIKV) re-emerged and caused numerous outbreaks in the world, and finally, was introduced into the Americas in 2013. The lack of CHIKV-specific therapies has led to the use of non-specific drugs. Chloroquine, which is commonly used to treat febrile illnesses in the tropics, has been shown to inhibit CHIKV replication in vitro. To assess the in vivo effect of chloroquine, two complementary studies were performed: (i) a prophylactic study in a non-human primate model (NHP); and (ii) a curative study "CuraChik", which was performed during the Reunion Island outbreak in 2006 in a human cohort. Clinical, biological, and immunological data were compared between treated and placebo groups. Acute CHIKV infection was exacerbated in NHPs treated with prophylactic administration of chloroquine. These NHPs displayed a higher viremia and slower viral clearance (p < 0.003). Magnitude of viremia was correlated to the type I IFN response (Rho = 0.8, p < 0.001) and severe lymphopenia (Rho = 0.8, p < 0.0001), while treatment led to a delay in both CHIKV-specific cellular and IgM responses (p < 0.02 and p = 0.04, respectively). In humans, chloroquine treatment did not affect viremia or clinical parameters during the acute stage of the disease (D1 to D14), but affected the levels of C-reactive Protein (CRP), IFNα, IL-6, and MCP1 over time (D1 to D16). Importantly, no positive effect could be detected on prevalence of persistent arthralgia at Day 300. Although inhibitory in vitro, chloroquine as a prophylactic treatment in NHPs enhances CHIKV replication and delays cellular and humoral response. In patients, curative chloroquine treatment during the acute phase decreases the levels of key cytokines, and thus may delay adaptive immune responses, as observed in NHPs, without any suppressive effect on peripheral viral load.

Therapy and pharmacological properties of hydroxychloroquine and chloroquine in treatment of systemic lupus erythematosus, rheumatoid arthritis and related diseases

OBJECTIVES

This review examines the pharmacokinetics, modes of action and therapeutic properties of the anti-malarial drugs, hydroxychloroquine (HCQ) and chloroquine (CQ), in the treatment of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and related conditions, as well as osteoarthritis (OA).

KEY FINDINGS

Both HCQ and CQ have historically been employed successfully for the treatment of SLE and RA for over 70 years. HCQ has been used extensively for SLE where it has a good reputation for controlling the dermatological complications in SLE. It has also been reported to effectively control the symptoms of Sjøgren's syndrome, as well as preventing thrombosis in phospholipid antibody (aPL) syndrome. In RA and SLE, HCQ is preferred because of the lower incidence of gastrointestinal adverse reactions compared with CQ and it might have a lower risk of ocular adverse reactions. There is increasing evidence that HCQ may reduce atherosclerosis and risks of cardiovascular disease in rheumatic patients. Both HCQ and CQ have been shown to improve glycaemia and reduce the risks of type II diabetes mellitus. Although both HCQ and CQ are effective in low-moderate RA, HCQ is now preferred as part of combination therapy for more severe disease. The advantages of combination therapy are that the doses of the individual drugs may be lowered so reducing adverse reactions. Both HCQ and CQ are diastereoisomers, have basic properties and are given as the sulphate and phosphate salts. While being relatively well absorbed orally and with good bioavailability, they have long and variable plasma terminal elimination half-lives (approximately 40-60 days). This reflects their high volume of distribution, V D (HCQ 44,000L; CQ 65,000L) which extends into aqueous compartments, long mean residence time (HCQ 1300 h; CQ 900 h) and with about half the drugs (metabolites) undergoing renal clearance. The strong binding to melanin reflects the ocular injury and dermatological properties of these drugs. The consensus is that the occurrence of ocular adverse reactions can be minimised by close attention to the dose (which should be set on a body weight basis) with regular (e.g. quarterly) retinal examination. Although HCQ and CQ can pass through the placenta, the use of these drugs during pregnancy does not appear to risk harm to the baby and might be beneficial to the mother with SLE and her child by controlling the SLE disease activity, which is known to be an important factor affecting pregnancy outcome. The modes of action of HCQ and CQ in these arthritides represent somewhat of an enigma. Undoubtedly, these drugs have multiple actions related, in part, their ability to accumulate in lysosomes and autophagosomes of phagocytic cells as well as affecting MHC Class II expression and antigen presentation; actions of the production of pro-inflammatory cytokines [e.g. interleukin-1 (IL-1) tumour necrosis factor-α (TNFα)]; control of toll-like receptor-9 activation; and leucocyte generation of reactive oxygen species (ROS); i.e. antioxidant activity. The actions of these drugs on T and B cells are less clear but may depend on these leucocyte-mediated actions. Anti-malarials also protect against cytokine-mediated cartilage resorption. This and other actions may underlie the potential benefits in treating OA. The exact relationships of these various actions, mostly determined in vitro, have not been specifically defined in vivo or ex vivo in relation to clinical efficacy.

OUTCOMES

HCQ and CQ have a good reputation for being effective and relatively safe treatments in SLE, mild-moderate RA and Sjøgren's syndrome. There is need for (a) more information on their mode of action in relation to the control of these diseases, (b) scope for developing formulations that have improved pharmacokinetic and therapeutic properties and safety, and (c) further exploring their use in drug combinations not only with other disease modifying agents but also with biologics.

Quantitative gait analysis as a method to assess mechanical hyperalgesia modulated by disease-modifying antirheumatoid drugs in the adjuvant-induced arthritic rat

In the present study, azothioprine, chloroquine, D-penicillamine, methotrexate and sodium aurothiomalate (gold salt) were evaluated for possible disease-modifying effects in the adjuvant-induced arthritis model of human rheumatoid arthritis in rats. Gait analysis was used to examine the role of disease-modifying antirheumatic drugs in the development of pain. Body weights were also measured to monitor the progression of disease and the systemic antiarthritic effects of the test compounds used in this study, as well as their systemic toxicity. Our results showed that azothioprine (5 mg/kg/day), chloroquine (12.5 mg/kg/day), sodium aurothiomalate (2.5 mg/kg/day) and methotrexate (1 mg/kg/week) not only inhibited the macroscopic changes such as erythema and swelling of limbs, but also exhibited significant reversal of gait deficits seen in the untreated or saline-treated arthritic rats. No reduction in the body weights were observed in the arthritic rats treated with azothioprine, chloroquine, sodium aurothiomalate and methotrexate. D-Penicillamine (12.5 mg/kg/day), however, showed a significant reduction (P < 0.03) in the body weights of the arthritic rats over a period of 22 days; furthermore, it was unable to show any reduction in arthritic score (P < 0.1). In earlier experiments, chloroquine and methotrexate failed to suppress carageenan-induced edema, suggesting that the mode of antiarthritic action may be different from those of nonsteroidal anti-inflammatory agents. Since these disease-modifying antirheumatic drugs are reported to have an immunomodulatory role, especially the gold salt, which influences the monocyte–macrophage system, it is suggested that the observed antiarthritic effects of disease-modifying antirheumatic drugs may be partly attributed to their immunomodulatory activity.

A new spin on an old model: in vivo evaluation of disease progression by magnetic resonance imaging with respect to standard inflammatory parameters and histopathology in the adjuvant arthritic rat

OBJECTIVE

To noninvasively examine the pathogenesis of rat adjuvant-induced arthritis (AIA) by magnetic resonance imaging (MRI), and to correlate MRI indices of disease progression with classic inflammatory parameters and histologic evaluation.

METHODS

AIA was established in male Lewis rats following subcutaneous injection in the right hindpaw with 0.5 mg of heat-killed Mycobacterium butyricum suspended in light mineral oil. In vivo MRI evaluations of soft tissue and bony changes in AIA rats with matched histopathology were correlated with changes in left hindpaw volumes, circulating leukocytes, acute-phase reactants, and urinary collagen crosslinks throughout the disease process.

RESULTS

MRI of arthritic tibiotarsal joints of the uninjected left hindpaws from AIA rats demonstrated 2 distinct phases of disease activity. The first phase, apparent between days 10 and 18, was characterized by periarticular inflammation with marked synovitis, synovial fibroplasia, and distension of the joint capsule into the surrounding tissue. The secondary phase, occurring between days 18 and 30, was marked by continued soft tissue inflammation, periostitis with osteolysis, and periosteal new bone formation progressing to a state of near complete ankylosis by day 30. These 2 phases of disease activity observed by MRI paralleled biochemical, cellular, and histologic markers of disease progression.

CONCLUSION

MRI can be used to noninvasively detect, monitor, and quantify the chronic synovitis and progressive destruction of soft tissue and bone in live AIA rats, thereby improving the ability to evaluate disease progression in this preclinical animal model of rheumatoid arthritis.

Methotrexate maintains bone mass by preventing both a decrease in bone formation and an increase in bone resorption in adjuvant-induced arthritic rats

We examined the effects of low doses methotrexate (MTX) and indomethacin (IND) on bone mass and turnover in normal male Sprague-Dawley rats and those with adjuvant-induced arthritis. Normal and the adjuvant (heat-killed mycobacterium)-injected rats, 6 weeks of age, were given MTX at daily doses of 0.05, 0.1, or 0.2 mg/kg body weight (BW) or IND at a daily dose of 1.0 mg/kg BW. Rats were killed at the start, or at 14 and 28 days. In normal rats, the administration of these agents did not change the lumbar and femoral BMD values, nor did the serum osteocalcin or urinary deoxypyridinoline (D-Pyr) levels. Lumbar trabecular osteoclast number (Oc.N/BS) and osteoclast surface (Oc.S/BS) were decreased in the rats given IND. In the arthritic rats, the administration of MTX did not prevent an early increase of paw edema in the adjuvant-injected limb, but late inflammatory edema was alleviated in the non-injected limb. However, MTX administration at a dose of 0.1-0.2 mg/kg BW maintained an age-dependent increase in the lumbar and femoral BMD values. While serum osteocalcin levels were decreased and urinary D-Pyr values were increased in the arthritic control rats, these bone markers remained at the levels of the normal rats. Decreases in mineral apposition rate (MAR) and bone formation rate (BFR/BS) and increases in the trabecular Oc.N/BS and Oc.S/BS values were prevented by MTX. While IND almost completely prevented inflammatory paw edema, it did not improve the parameters of bone formation. An increase in osteoclasts was prevented and the osteopenia in the lumbar and the femoral bone was only partially prevented by IND. These data suggest that MTX improves bone mass and turnover in the arthritic rat, in which several cytokines that affect bone cells are involved. An increase in bone resorption may be due to prostaglandins, but bone formation defect was suggested to be due to other cytokines such as IL-1, IL-6, and TNF-alpha in this model.

Enhanced resistance to Cryptococcus neoformans infection induced by chloroquine in a murine model of meningoencephalitis

Although the pathogenesis of cerebral cryptococcosis is poorly understood, local immune cells, such as microglia and astrocytes, likely play a critical role in containing infection. Chloroquine (CQ) is a weak base that accumulates within acidic vacuoles and increases their pH. Consequently, proteolytic activity of lysosomal enzymes and intracellular iron release/availability are impaired, resulting in decreased availability of nutrients crucial to microorganism survival and growth in the host. We found that CQ enhances BV2 microglial-cell-mediated anticryptococcal activity in vitro. The phenomenon is (i) evident when both unopsonized and opsonized microorganisms are used and (ii) mimicked by NH4Cl, another weak base, and by bafilomycin A1, an inhibitor of vacuolar-type H+-ATPases. In vivo, intracerebral administration of CQ before lethal local challenge with Cryptococcus neoformans results in a significant augmentation of median survival time and a marked reduction of yeast growth in the brain and is associated with the enhancement of local interleukin 1beta (IL-1beta) and IL-6 mRNA transcripts. Overall, these results provide the first evidence that CQ enhances anticryptococcal host defenses.

Complete prevention of the clinical expression of adjuvant-induced arthritis in rats by cyclosporin-A and lobenzarit: the regulation of lymph node cell populations and cytokine production

A single dose of either cyclosporin-A (CsA) or lobenzarit (CCA) given with an arthrogenic adjuvant completely prevented expression of experimental adjuvant arthritis in rats. The aim of this study was to understand how these drugs prevented the arthritis expression by studying the popliteal lymph nodes draining the arthritic joints at various times after adjuvant injection. Neither drug affected the proliferation in popliteal lymph nodes at the time arthritis was normally expressed, however, there was a marked change in the types of cells present. Immunofluorescence assays showed a reduction in the proportion of CD4+ cells, while the proportion of B-lymphocytes was almost doubled. This coincided with a marked elevation in the ability of these cells to produce interleukin (IL)-6. At the same time production of other cytokines (IL-2, tumour necrosis factor (TNF) and interferon (IFN)-gamma) was not greatly affected. However, one day after adjuvant injection IL-2 and IFN-gamma production was reduced. In vitro experiments showed that IL-6 production by lymphoid cells was relatively unaffected by CsA and CCA but IL-2, TNF and IFN-gamma were suppressed by CsA. The results indicate that CsA and CCA may modify the response to the arthritic adjuvant by specifically inhibiting IL-2, TNF and IFN-gamma production at the time of adjuvant injection. The lack of inhibition of IL-6 by these drugs reveals it may not play a key role in the initiation of this model of chronic inflammation.

Effects of antirheumatic agents on cytokines

A review of the literature concerning the effects of traditional antirheumatic drugs on cytokines and the cytokine and anticytokine approaches already used in the therapy of rheumatoid arthritis (RA) is presented. Many antirheumatic drugs are capable of cytokine modulation in vitro. Corticosteroids inhibit the transcription of a broad spectrum of genes including those encoding monocyte, T cell-derived cytokines and several hemopoietic growth factors, whereas drugs such as cyclosporin A and D-penicillamine interfere with T cell activation more specifically by suppressing interleukin 2 (IL-2) production. The in vivo effects of drug therapy on cytokines in RA patients are less well established. Gold compounds reduce circulating IL-6 levels and the expression of monocyte-derived cytokines, such as IL-1, tumor necrosis factor (TNF), and IL-6, in the rheumatoid synovium. Decreases in circulating IL-6, soluble IL-2 (sIL-2R), and TNF receptors and in synovial fluid IL-1 levels have been reported with methotrexate. Reductions in circulating IL-6 and sIL-2R concentrations have also been observed with cyclosporin and corticosteroids, whereas azathioprine reduces IL-6 but not sIL-2R. Studies on sulfasalazine are conflicting and the in vivo effects of D-penicillamine and antimalarials have not been studied yet. Interferon gamma therapy is not effective in RA but may prove a useful antifibrotic for systemic sclerosis. Colony stimulating factors improve the granulocytopenia associated with Felty's syndrome or drug toxicities but can induce arthritis flares and should be reserved to treat infectious complications. Promising results are being obtained with selective antagonism of TNF and IL-1 in RA, and combinations of anticytokine strategies with traditional antirheumatic drugs have been already envisaged. These should preferably be based in a broader knowledge of the effects of antirheumatic agents on the cytokine network.

Meloxicam: a potent inhibitor of adjuvant arthritis in the Lewis rat

The effects of meloxicam, piroxicam, diclofenac and tenidap on the swelling of hind paws, radiologically-detectable bone and cartilage destruction of hind paws, increase in spleen weight, increase in erythrocyte sedimentation rate and changes in serum protein composition in male Lewis rats with adjuvant arthritis were studied following once-daily oral administration of these drugs for 21 days. All the drugs dose-dependently inhibited hind paw swelling. For equal activity against hind paw swelling caused by the secondary reaction, the required daily dose of piroxicam was about twice that of meloxicam; those of diclofenac and tenidap were about 3.5 and 60 times higher respectively. The bone and cartilage destruction induced by adjuvant arthritis were inhibited by meloxicam at low daily doses and by piroxicam at doses approximately four times those of meloxicam. Diclofenac and tenidap had only a weak effect on radiologically-detectable lesions when administered at doses sufficient to reduce paw swelling. Meloxicam also had a dose-dependent corrective effect on the systemic changes which occur in adjuvant arthritic rats, e.g. increase in spleen weight, increase in erythrocyte sedimentation rate and changes in serum protein composition. Piroxicam produced similar effects, at 3-4 times higher doses. Diclofenac and tenidap did not show comparable effects when administered at appropriate doses. These findings indicate that the action of meloxicam and piroxicam differs from that of diclofenac and tenidap in adjuvant arthritis in the Lewis rat. At oral doses which significantly reduce edema formation, only meloxicam and piroxicam showed a significant effect on systemic parameters of adjuvant disease in the Lewis rat.

Changes in urinary deoxypyridinoline level and vertebral bone mass in the development of adjuvant-induced arthritis in rats

This study was designed to determine the effect of bone resorption on the development of generalized osteopenia in adjuvant-induced arthritic rats. Thirty of a total of sixty male SD rats, 6 weeks of age, were injected with killed mycobacterium butyricum suspended in mineral oil into the right hind paw and assigned to six groups of 5 animals each. The other thirty animals served as the age-matched noninjected controls. Animals were sacrificed at 4, 7, 10, 14, 21, and 28 days post-injection after measuring the bilateral hind-paw volumes. Twenty-four-hour urinary samples were obtained before sacrifice and the levels of deoxypyridinoline (D-Pyr) and creatinine (CR) were measured. Plasma intact osteocalcin levels were measured by a sandwich enzyme immunoassay at the start, 14 and 28 days after injection. Bone mineral measurement and histomorphometrical analyses were performed on specimens of the third lumbar vertebral body. On the seventh day after injection, arthritic rats showed significant decreases in the values of bone mineral content (BMC) and density (BMD) when compared to controls. Urinary D-Pyr/Cr ratios, however, did not increase on the seventh day, showing a significant increase on the tenth day after injection. The serum osteocalcin level was significantly reduced on the fourteenth day. The trabecular bone volume (BV/TV) in the arthritic rats showed a significant decrease from the seventh day. The trabecular thickness (Tb.Th) value significantly decreased on the seventh day after injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulation of alpha 1-acid glycoprotein (AGP) gene induction following honey bee venom administration to adjuvant arthritic (AA) rats; possible role of AGP on AA development

Honey bee venom (HBV) administration to adjuvant arthritic (AA) rats resulted in a significant suppression of arthritis and in suppression of the hepatic acute phase alpha 1-acid glycoprotein (AGP) gene induction at the early stages of disease development. AGP administration in AA rats resulted in acceleration of arthritis development and in increase of severity and duration of the disease. IL-1, IL-6, tumour necrosis factor (TNF) and glucocorticoids alone are not responsible for the HBV-mediated AGP gene down-regulation. These results indicate that AGP gene expression in AA and HBV-treated AA rats involves the interaction of several factors, and that AGP plays a role for AA development in rats.

Bone morphometric changes in adjuvant-induced polyarthritic osteopenia in rats: evidence for an early bone formation defect

Adjuvant polyarthritis (AP) in rats is known to result in extensive bone loss. This study investigates the mechanisms responsible for the early trabecular osteopenia evaluated at a single point in time--2 weeks after adjuvant injection--in the hindpaw of female Lewis rats using biochemical and histomorphometric methods. At this early point in time, the inflammation was generalized (inflammatory score, 20; albumin/globulin, -80% versus control). Histomorphometric analysis of the noninjected femur showed that the trabecular bone volume was significantly decreased (-28% versus control) in both proximal and distal parts, and the femur growth rate was unaffected. The trabecular osteopenia was associated with a 90% decrease in osteoid surface and a concomitant thinning (-19%) of the trabeculae. Both the double-fluorescence-labeled surface and the osteoblast surface were also markedly decreased (-75%). In addition, the mineral apposition rate was reduced (-50%) and the bone formation rate was decreased by as much as 90%. The trabecular bone volume was decreased in relation with the extent of double-fluorescence labeling (r = 0.38, p = 0.03) and bone formation rate (r = 0.42, p = 0.01), suggesting that the generalized osteopenia resulted from the reduced bone formation. This was associated with a 26% reduction in plasma osteocalcin. Neither the osteoclast surface nor the number of osteoclasts was consistently affected. However, urinary hydroxyproline was increased by 100-200%, which likely reflected the cartilage and bone destruction at the site of injection. The present data show that the early extensive osteopenia observed 2 weeks after AP induction in rats results from defective bone formation with unchanged bone resorption. The role of cytokines in such an inhibitory effect on bone formation remains to be determined.

The modulation of interleukin 1 production by interferon gamma, and the inhibitory effects of gold compounds

We have studied the in vitro effects of gold sodium thiomalate (GST) and auranofin (Auf) on the production of interleukin 1 (IL1) expressed as thymocyte co-stimulatory activity (TCSA), and interleukin 1 beta (IL1 beta) as modulated by interferon gamma (IFN gamma). Adherent cells (ADC), of which 80% were monocytes, were obtained from human peripheral blood, and stimulated with lipoprotein polysaccharide (LPS) for 24-48 h. TCSA and IL1 beta production by fresh ADC (0-24 h) was significantly higher than that of aged ADC (24-48 h). The addition of IFN gamma to ADC cultures, however, maintained the capacity of aging ADC to respond optimally to LPS. The addition of GST or Auf inhibited this modulatory effect of IFN gamma, resulting in a marked reduction of TCSA and IL1 beta production. The effects of IFN gamma on the production of IL1 may be important in the pathogenesis of rheumatoid arthritis (RA). The inhibition by GST and Auf of IFN gamma modulation may contribute to the therapeutic efficacy of these drugs in RA.

Differential effects of anti-arthritic agents on subnormal plasma iron levels in adjuvant arthritic rats

Nonsteroidal anti-inflammatory drugs (NSAID's) and other antirheumatic compounds such as disease modifying antirheumatic drugs (DMARD's), immunosuppressives and glucocorticoids were tested to determine if daily medication for two weeks could elevate subnormal levels of plasma iron in adjuvant-arthritic (AA) rats. Aspirin, indomethacin, ibuprofen and phenylbutazone were chosen as representative carboxylic acids and pyrazole NSAID's. Although NSAID's at all doses significantly reduced noninjected paw swelling, no NSAID significantly enhanced subnormal plasma iron levels in AA rats. In contrast, the standard DMARD's auranofin and gold sodium thiomalate, as well as the glucocorticoid, dexamethasone and the immunosuppressives, methotrexate and cyclosporin-A all significantly restored plasma iron levels 28 to 100 percent. Plasma iron depression, a parameter of the acute phase response probably under regulation by pro-inflammatory cytokines, is not reversed by NSAID treatment. This appears to be a useful method for distinguishing NSAID's from other anti-arthritic compounds.