Hydroalcoholic crude extract of Casearia sylvestris Sw. reduces chronic post-ischemic pain by activation of pro-resolving pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Casearia sylvestris Sw. is widely used in popular medicine to treat conditions associated with pain.

AIM OF THE STUDY

The present study investigated the influence of hydroalcoholic crude extract of Casearia sylvestris (HCE-CS) and contribution of pro-resolving mediators on mechanical hyperalgesia in a mouse model of chronic post-ischemia pain (CPIP).

METHODS AND RESULTS

Male Swiss mice were subjected to ischemia of the right hind paw (3h), then reperfusion was allowed. At 10min, 24h or 48h post-ischemia/reperfusion (I/R), different groups of animals were treated with HCE-CS (30mg/Kg, orally [p.o]), selected agonists at the pro-resolving receptor ALX/FPR2 (natural molecules like resolvin D1 and lipoxin A4 or the synthetic compound BML-111; 0.1-1µg/animal) or vehicle (saline, 10mL/Kg, s.c.), in the absence or presence of the antagonist WRW4 (10µg, s.c.). Mechanical hyperalgesia (paw withdrawal to von Frey filament) was asseseed together with histological and immunostainning analyses. In these settings, pro-resolving mediators reduced mechanical hyperalgesia and HCE-CS or BML-111 displayed anti-hyperalgesic effects which was markedly attenuated in animals treated with WRW4. ALX/FPR2 expression was raised in skeletal muscle or neutrophils after treatment with HCE-CS or BML-111.

CONCLUSION

These results reveal significant antihyperalgesic effect of HCE-CS on CPIP, mediated at least in part, by the pathway of resolution of inflammation centred on the axis modulated by ALX/FPR2.

A peptide derived from TIMP-3 inhibits multiple angiogenic growth factor receptors and tumour growth and inflammatory arthritis in mice

The binding of vascular endothelial growth factor (VEGF) to VEGF receptor-2 (VEGFR-2) on the surface of vascular endothelial cells stimulates many steps in the angiogenic pathway. Inhibition of this interaction is proving of value in moderating the neovascularization accompanying age-related macular degeneration and in the treatment of cancer. Tissue inhibitor of metalloproteinases-3 (TIMP-3) has been shown to be a natural VEGFR-2 specific antagonist-an activity that is independent of its ability to inhibit metalloproteinases. In this investigation we localize this activity to the C-terminal domain of the TIMP-3 molecule and characterize a short peptide, corresponding to part of this domain, that not only inhibits all three VEGF-family receptors, but also fibroblast growth factor and platelet-derived growth factor receptors. This multiple-receptor inhibition may explain why the peptide was also seen to be a powerful inhibitor of tumour growth and also a partial inhibitor of arthritic joint inflammation in vivo.

The impact of endogenous annexin A1 on glucocorticoid control of inflammatory arthritis

Objectives

To establish the role and effect of glucocorticoids and the endogenous annexin A1 (AnxA1) pathway in inflammatory arthritis.

Methods

Ankle joint mRNA and protein expression of AnxA1 and its receptors were analysed in naive and arthritic mice by real-time PCR and immunohistochemistry. Inflammatory arthritis was induced with the K/BxN arthritogenic serum in AnxA1^+/+ and AnxA1^−/− mice; in some experiments, animals were treated with dexamethasone (Dex) or with human recombinant AnxA1 or a protease-resistant mutant (termed SuperAnxA1). Readouts were arthritic score, disease incidence, paw oedema and histopathology, together with pro-inflammatory gene expression.

Results

All elements of the AnxA1 pathway could be detected in naive joints, with augmentation during ongoing disease, due to the infiltration of immune cells. No difference in arthritis intensity of profile could be observed between AnxA1^+/+ and AnxA1^−/− mice. Treatment of mice with Dex (10 µg intraperitoneally daily from day 2) afforded potent antiarthritic effects highly attenuated in the knockouts: macroscopic changes were mirrored by histopathological findings and pro-inflammatory gene (eg, Nos2) expression. Presence of proteinase 3 mRNA in the arthritic joints led the authors to test AnxA1 and the mutant SuperAnxA1 (1 µg intraperitoneally daily in both cases from day 2), with the latter one being able to accelerate the resolving phase of the disease.

Conclusion

AnxA1 is an endogenous determinant for the therapeutic efficacy of Dex in inflammatory arthritis. Such an effect can be partially mimicked by application of SuperAnxA1 which may represent the starting point for novel antiarthritic therapeutic strategies.

Inhibition of the diclofenac-induced cyclooxygenase-2 activity by paracetamol in cultured macrophages is not related to the intracellular lipid hydroperoxide tone

Paracetamol, a weak inhibitor of cyclooxygenase COX-1 and COX-2 activities, has been reported to inhibit the activity of COX-2 induced by diclofenac in J774.2 macrophage cell line. The lack of inhibition of COX-2 by paracetamol in inflamed tissues and thereby the lack of anti-inflammatory activity has been attributed to high lipid hydroperoxide (LHP) tone. In this study, we demonstrate that the inhibition of the diclofenac-induced COX-2 activity in J774.2 cells by paracetamol is not related to the intracellular LHP tone as paracetamol inhibited this activity in the absence and presence of T-butyl hydroperoxide, which is an LHP donor, to the same extents. In fact, treatment of the cells with diclofenac resulted in an increase in the LHP tone. Stimulation of the cells with lipopolysaccharide (LPS) results in the induction of a COX-2 activity, which was not inhibited by paracetamol. This represents the classical induction pathway for COX-2. LPS stimulation did not alter the LHP tone. These results suggest that the enzymatic activity of the diclofenac-induced COX-2 protein does not depend on the supply of hydroperoxides to its peroxidase active site.

Paracetamol-induced hypothermia is independent of cannabinoids and transient receptor potential vanilloid-1 and is not mediated by AM404

In recent years, there has been increasing interest in hypothermia induced by paracetamol for therapeutic purposes, which, in some instances, has been reported as a side effect. Understanding the mechanism by which paracetamol induces hypothermia is therefore an important question. In this study, we investigated whether the novel metabolite of paracetamol, N-(4-hydroxyphenyl)arachidonylamide (AM404), which activates the cannabinoid (CB) and transient receptor potential vanilloid-1 (TRPV1) systems, mediates the paracetamol-induced hypothermia. The hypothermic response to 300 mg/kg paracetamol in CB(1) receptor (CB(1)R) and TRPV1 knockout mice was compared to wild-type mice. Hypothermia induced by paracetamol was also investigated in animals pretreated with the CB(1)R or TRPV1 antagonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperdinyl-1H-pyrazole-3-carboxamide trifluoroacetate salt (AM251) or 4'-chloro-3-methoxycinnamanilide (SB366791), respectively. In CB(1)R or TRPV1 knockout mice, paracetamol induced hypothermia to the same extent as in wild-type mice. In addition, in C57BL/6 mice pretreated with AM251 or SB366791, paracetamol induced hypothermia to the same extent as in control mice. AM404 failed to induce hypothermia at pharmacological doses. Inhibition of fatty acid amide hydrolase (FAAH), which is involved in the metabolism of paracetamol to AM404, did not prevent the development of hypothermia with paracetamol. Paracetamol also induced hypothermia in FAAH knockout mice to the same extent as wild-type mice. We conclude that paracetamol induces hypothermia independent of cannabinoids and TRPV1 and that AM404 does not mediate this response. In addition, potential therapeutic value of combinational drug-induced hypothermia is supported by experimental evidence.

Cyclooxygenase enzymes and their products in the carrageenan-induced pleurisy in rats

Rodent models of inflammation have helped in our understanding of the inflammatory process and also for the screening of compounds with anti-inflammatory potential. Although they do not represent a particular inflammatory disease in humans, cavity models of inflammation in rodents are easy to induce and to quantify the inflammatory reaction as well as to harvest the inflammatory exudates for cytological, biochemical and molecular biological analysis. Of these models, the carrageenan-induced pleurisy model has been extensively used to study the role of the cyclooxygenase (COX) enzymes and the prostaglandins in acute inflammation and also for the screening of COX-inhibiting anti-inflammatory drugs.

Activation of macrophage peroxisome proliferator-activated receptor-gamma by diclofenac results in the induction of cyclooxygenase-2 protein and the synthesis of anti-inflammatory cytokines

Cyclooxygenase-2 (COX-2) is an inducible isoform of the COX family of enzymes central to the synthesis of pro-inflammatory prostaglandins. Induction of COX-2 is mediated by many endogenous and exogenous molecules that include pro-inflammatory cytokines and bacterial lipopolysaccharide (LPS). It has been demonstrated that COX-2 can also be induced by diclofenac in cultured J774.2 macrophages. This induction was delayed compared to COX-2 induced by LPS and paracetamol selectively inhibited activity of this protein. The aim of the present study was to determine the transcription factor involved in the production of COX-2 after treatment of J774.2 cells with 500 microM diclofenac. Pre-treatment of cells with the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) antagonists GW9662 (0.1-1 microM) or biphenol A Diglycidyl Ether (100-200 microM) resulted in reduction of the induction of COX-2 by diclofenac, but not by LPS. Induction of COX-2 by the PPAR-gamma agonist 15deoxyDelta(12,14)prostaglandin J(2) was also reduced when the cells were pre-treated with the PPAR-gamma antagonists BADGE or GW9662. On the other hand, pre-treatment of cells with the nuclear factor-kappa-B (NF-kappaB) Super-repressor IkappaBalpha (150-600 nM) reduced the induction of COX-2 by LPS, but not by diclofenac. We, therefore, have identified that PPAR-gamma activation is a requirement for COX-2 induction after diclofenac stimulation of J774.2 cells. These results along with the finding that treatment of J774.2 macrophages with diclofenac resulted in the release of the anti-inflammatory cytokines, interleukin-10 and transforming growth factor-beta suggest that the diclofenac-induced COX-2 protein may possess anti-inflammatory actions.

The inhibition of neutrophil-endothelial cell adhesion by hyaluronan independent of CD44

OBJECTIVE

To study the effect of hyaluronan on cell adhesion and recruitment both in vitro and in vivo, since hyaluronan both inhibits restenosis and is anti-inflammatory. When administered to animals undergoing angioplasty the recruitment of cells into the restenotic plaque is inhibited, as well as into inflammatory lesions. The recent discovery that ICAM-1 binds hyaluronan and exhibits the B(X(7))B HA binding motif, led us also to investigate whether cell adhesion could be modulated by hyaluronan.

MATERIALS AND METHODS

Human neutrophils were adhered to human umbilical vein (HUVEC) or Ea.hy.926 HUVEC cells stimulated with phorbol myristate acetate (PMA) or tumour necrosis factor (TNFalpha). Neutrophil binding in vivo utilized FMLP-stimulated hamster cheek pouch post-capillary venules.

RESULTS

Hyaluronan inhibited human neutrophil adhesion to both PMA and TNFalpha-stimulated HUVEC. Ea.hy.926 human immortal HUVECs expressed ICAM-1 in response to TNFalpha and PMA. E-selectin was also upregulated by 6 h with TNFalpha but not significantly with PMA. TNFalpha induced CD44 expression within 4 h, but PMA not significantly up to 6 h. However, specific binding of [125I]hyaluronan to Ea.hy.926 cells was increased by PMA-stimulation at 4 h. Neutrophil adhesion to PMA-stimulated Ea.hy.926 HUVECs was inhibited in a concentration dependent fashion by both anti-ICAM-1 and hyaluronan (1 ng/ml-10 microg/ml) at 4 h. At 1 mg/ml adhesion was stimulated by hyaluronan. Hyaluronan had no effect on neutrophil adhesion to resting Ea.hy.926 cells. Hyaluronan (25 mg/kg, i.v.) inhibited cell adhesion to FMLP-stimulated post capillary venules of the hamster cheek pouch, whilst leaving cell rolling unaffected.

CONCLUSIONS

These results show that hyaluronan, at concentrations below those where intra-molecular associations occur, binds selectively to stimulated endothelial cells and inhibits neutrophil adhesion in vitro and in vivo via a mechanism which may involve molecules other than CD44, such as ICAM-1.

Heat-shock proteins and their role in chondrocyte protection, an application for autologous transplantation

Articular cartilage injury presents a unique therapeutic challenge. As cartilage possesses no blood or nerve supply of its own it has a particular susceptibility to early injury and a poor capacity for self-repair. Treatment options are limited and injury can eventually lead to osteoarthritis. Autologous chondrocyte transplantation is an exciting therapeutic development, but despite initial encouraging results, graft failure and formation of fibro- as opposed to hyaline cartilage remain problematic. Bleeding is an inevitable consequence of surgery, and blood-induced cartilage damage is well documented. It is hypothesised here that protecting chondrocytes against blood could significantly improve results. Heat-shock protein induction may confer chondroprotection. The expression of heat-shock proteins in human chondrocytes and rat femoral head cartilage following heat shock was analysed by Western blotting, and red-blood-cell-induced chondrocyte death was assessed by cell viability and apoptosis by flow cytometry. We demonstrate that heat-shock induced expression of heat-shock protein 70 (HSP70) (rat and human) and HSP32 (human). Blood and blood products reduced rat cartilage proteoglycan synthesis and human chondrocyte viability, and induced human chondrocyte apoptosis at concentrations considerably lower than those reported previously. The induction of HSP70 in rat cartilage was ineffective in reducing chondrocyte death in the absence or presence of red blood cells or red cell products. Heat shock to human chondrocytes reduced low levels of apoptosis (<20%) and cell death induced by low levels of blood products, but not higher levels. Induction of HSP32 with diacetylrhein appeared to be more effective and may hold greater promise. Blood has potent adverse effects on chondrocytes and the induction and chondroprotective effects of heat-shock proteins could be applied to increase the initial success of implanted chondrocytes improving the outcome of autologous chondrocyte transplantation.

Study of a combined percutaneous local anaesthetic and the TDS system for venepuncture

Transdermal Delivery System (TDS) is a liquid formulation which can be applied to the skin via a metered pump spray to deliver drug across skin. This placebo controlled, double blind trial compared anaesthetic properties of two TDS systems (TDS alpha and TDS beta) with placebo. The active and placebo treatments were applied to the dorsum of the hands, bilaterally and simultaneously for 5 min on 100 healthy volunteers. Following cannulation, pain perception was measured using the verbal rating score (VRS) and visual analogue score (VAS). Lidocaine plasma levels were assessed at 0 and 2 h. The VRS and VAS results show that TDS beta significantly decreased pain score compared to placebo (p < 0.02). Blood lidocaine at 2 h post application was also higher for TDS beta than for TDS alpha, suggesting that a 5 min application of TDS beta was effective in delivering local anaesthetic and accelerating the onset of skin anaesthesia prior to venous cannulation in adults.

The modulation of intra-articular inflammation, cartilage matrix and bone loss in mono-articular arthritis induced by heat-killed Myobacterium tuberculosis

Inflammation models for the assessment of anti-rheumatic drug activity utilize a variety of stimuli and sites. However, the determination of cartilage and bone degradation remains time consuming and problematic. A rapid rat model of Mycobacterium tuberculosis monoarticular arthritis with induces of inflammation, as well as patellar cartilage proteoglycan and bone degradation has been reported. This study characterizes this model with respect to the actions of anti-rheumatic drugs. Dexamethasone, cyclosporin and prednisolone inhibited all three parameters. Methotrexate inhibited joint inflammation alone, whilst azathioprine was without effect. Levamisole inhibited cartilage and bone degradation without affecting joint inflammation. NSAIDs were divided in their actions. Naproxen, piroxicam, diclofenac and tiaprofenic acid all inhibited joint inflammation and bone loss, but naproxen and piroxicam both significantly potentiated cartilage proteoglycan loss. This model appears to rely on cellular recruitment at this early stage, the anti-metabolites being ineffective. The modulation of inflammation can result in a protection against cartilage and bone damage in arthritis; however, certain NSAIDs are detrimental to cartilage integrity. The pharmacological manipulation of inflammatory arthritis can therefore dislocate inflammation from its effects on tissue destruction.

Tetrahydro-derivatives of cortisone promote granulomatous tissue angiogenesis in vivo on topical application in hyaluronan

Hyaluronan is an essential component of the extracellular matrix and alters the quality of wound healing as well as modulating angiogenesis. It is also used as a topical and i.v. drug delivery system. We have previously reported that cortisone in hyaluronan gel inhibits granulomatous tissue angiogenesis, as does tetrahydrocortisol (THF) administered s.c. We have investigated the effects of tetrahydrocortisone (THE) and THF administered s.c. on granulomatous tissue angiogenesis, and compared this with their topical administration in hyaluronan. Carmine/gelatin vascular casts of murine chronic granulomatous air pouches were formed and the vascularity index calculated as μg carmine/mg granuloma dry mass. THF inhibited angiogenesis as previously reported; however, THE stimulated angiogenesis significantly. On topical application in 2.5% hyaluronan both steroids dramatically stimulated granulomatous tissue angiogenesis, THE by 100% and THF by 300% at 1mg/kg. Previous work has shown that topical hyaluronan alone has little effect on granulomatous tissue angiogenesis. Thus the topical application of the tetrahydro-steroid derivatives results in the stimulation of angiogenesis and converts the angiostatic properties of THF to an angiogenic profile. These formulations may therefore have potential as topical therapies, e.g. for the acceleration of wound healing.

Sulfated glycosaminoglycans and glucosamine may synergize in promoting synovial hyaluronic acid synthesis

High-molecular-weight hyaluronic acid (HA) produced by the synovium may function physiologically to aid preservation of cartilage structure and prevent arthritic pain; both the size and concentration of HA in synovial fluid are diminished in osteoarthritis (OA). Glucosamine therapy for OA can be expected to increase synovial HA production by providing rate-limiting substrate. In addition, certain sulfated glycosaminoglycans and polysaccharides - including chondroitin sulfate (CS), dermatan sulfate, and pentosan polysulfate - stimulate synovial HA production, apparently owing to a hormone-like effect triggered by the binding of these polymers to membrane proteins of synovial cells. Surprisingly, a significant proportion of orally administered CS is absorbed as intact polymers - apparently by pinocytosis. These considerations may rationalize clinical studies concluding that oral CS provides slow-onset but durable pain relief and functional improvement in OA. The possibility that oral glucosamine and CS may interact in a complementary or synergistic fashion to improve synovial fluid HA content in OA should be assessed in clinical studies, and the potential of adjunctive CS administration to improve the clinical response achievable with optimal intakes of glucosamine should likewise be evaluated. In light of the fact that the synovium virtually functions as a 'placenta' for cartilage, focusing on synovium as the target for therapeutic intervention in OA may be a rational strategy.

Effects of low dose ionizing radiation on murine chronic granulomatous tissue

PURPOSE

Substantial clinical evidence shows the efficacy of low-dose radiotherapy in the treatment of a wide variety of benign conditions. However, experimental investigations into these empirically clinical observations remain scarce. We investigated in vivo low-dose radiation effects on chronic granulomatous tissue by using the air pouch model in mice.

MATERIAL AND METHODS

Chronic granulomatous air pouches were induced in mice and dosed according to 4 protocols: group I: sham control; group II: 2 Gy on day 2; group III: 2 Gy on day 6; group IV: 5 daily doses of 0.5 Gy from day 2 to 6. On day 7 after granuloma induction the granuloma wet and dry weight was estimated, the vascular content was assessed by the formation of vascular casts incorporating carmine, the inducible nitric oxide synthase (iNOS)- and heme oxygenase 1 (HO-1)-expression in tissue homogenates was assessed by Western blot analysis, and the immunohistochemical localization of iNOS was carried out in cryostat sections of the granulomatous tissue.

RESULTS

We did not observe any significant reduction in granulomatous tissue wet weight or dry weight following the different radiation treatments, which indicates that anti-proliferative effects in response to the low radiation doses used, are probably not involved in the effects of anti-inflammatory radiotherapy. A single dose of 2 Gy on day 2, as well as fractionated treatment with 5 x 0.5 Gy lead to an increase in vascularity. iNOS-expression in the homogenized granulomatous tissue was decreased, being most pronounced after single-dose irradiation with 2 Gy on day 2, early on in the acute phase of inflammation. In contrast, the HO-1-expression was increased in all irradiated groups.

CONCLUSION

Low doses of radiation interfere with the NO- and the HO-1 pathway. Since NO contributes to several aspects of inflammation such as oedema formation and inflammatory pain, we put forward the hypothesis, that the inhibitory effect of low doses of ionizing radiation on the NO pathway is one radiobiological mechanism underlying the clinically observed efficacy of anti-inflammatory radiotherapy and might result in the reduction of swelling as well as relief of pain. Furthermore, the suppression of iNOS activity could be due to the increase in the stress protein HO-1 by low dose radiotherapy.

The effects of cyclooxygenase 2 inhibitors on cartilage erosion and bone loss in a model of Mycobacterium tuberculosis-induced monoarticular arthritis in the rat

Selective cyclooxygenase 2 (COX 2) inhibitors NS-398 and nimesulide were investigated for their effects on patellar cartilage and bone content in a model of Mycobacterium tuberculosis (M.tb)-induced monoarticular arthritis in the rat. The protective/destructive properties of these nonsteroidal antiinflammatory drugs (NSAIDs) were compared with piroxicam, known to accelerate cartilage breakdown and reduce bone erosion in this model in comparison to untreated arthritic controls. Male CFHB Wistar rats were injected intraarticularly with heat killed M.tb into the left stifle joint, resulting in loss of patellar cartilage glycosaminoglycans (GAG), bone erosion and inflammation. The right stifle joint received saline. Animals were dosed daily, p.o., with NS-398 (1, 10 mg/kg), nimesulide (0.5, 5 mg/kg) or piroxicam (10 mg/kg). Four days after M.tb injection, patellar GAG content, bone weight and joint swelling were measured in drug-treated animals and untreated arthritic controls. Changes in the left joint were compared to the right. The expression and distribution of COX 2 protein was determined by immunocytochemistry in synovial tissue from arthritic controls over the time course. Focal accumulations of inflammatory cells were positively immunolabelled for COX 2 in the synovium from the left stifle joint of untreated arthritic animals, 6 h after injection of M.tb. Labeling of inflammatory cell infiltrates increased and was widespread in the synovium at 24 h. By day 4 fibroblasts were positively labelled for COX 2 in addition to polymorphonuclear and mononuclear leukocytes. Piroxicam and nimesulide at the higher dose significantly exacerbated M.tb-induced cartilage GAG loss while NS-398 was without effect. Both COX 2 inhibitors did not alter M.tb-induced patellar bone loss. In contrast, piroxicam significantly reduced bone loss. All COX inhibitors significantly reduced joint swelling. In conclusion, the selective inhibition of COX 2 may result in the amelioration of synovitis with a lowered risk of NSAID-induced cartilage damage in rheumatic disease.

Mechanisms of the anti-inflammatory activity of low-dose radiation therapy

PURPOSE

To investigate the hypothesis that modulation of the function of activated macrophages is one of the mechanisms of the clinically observed anti-inflammatory and analgesic efficacy of low-dose radiotherapy in the treatment of a variety of painful joint diseases with total doses between 1 and 6 Gy.

MATERIALS AND METHODS

Metabolic activity, cell proliferation, reproductive integrity, nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression by unstimulated or [LPS/gamma-IFN-stimulated macrophages in vitro was investigated at different times after radiation doses ranging from 0.3 Gy to 10 Gy. In vivo, chronic granulomatous air pouches were induced in mice and either sham treated or irradiated with 2 Gy on day 2 or day 6, or with five daily doses of 0.5 Gy. On day 7, the iNOS expression was assessed by Western blot and localized by immuno-histochemistry in cryostat sections.

RESULTS

In stimulated macrophages, metabolic activity, proliferation and reproductive integrity were not affected by radiation doses up to 10 Gy since they are apparently irreversible post-mitotic cells. However, a dose-dependent modulation of the NO pathway was observed with significant inhibition by the low radiation doses used in anti-inflammatory radiotherapy but with super-stimulation by the high radiation doses used in cancer therapy.

CONCLUSIONS

The empirically based anti-inflammatory radiotherapy of benign diseases appears to act through specific modulation of different pathways of inflammatory reactions such as the nitric oxide pathway in stimulated macrophages.

The codependence of angiogenesis and chronic inflammation

Angiogenesis is the growth of new blood vessels from existing ones. It is an important aspect of new tissue development, growth, and tissue repair. It is also a component of many diseases including cancer, blindness, and chronic inflammation such as rheumatoid arthritis (RA) and psoriasis. There is considerable evidence to suggest that angiogenesis and chronic inflammation are codependent; recent studies have begun to reveal the nature of this link, which involves both augmentation of cellular infiltration and proliferation and overlapping roles of regulatory growth factors and cytokines. Through these studies, we have begun to understand the codependence of chronic inflammation and angiogenesis, the potential benefits of targeting angiogenesis in the treatment of chronic inflammation, and of targeting chronic inflammation to affect angiogenesis.

The inhibition of colon-26 adenocarcinoma development and angiogenesis by topical diclofenac in 2.5% hyaluronan

Topical diclofenac in 2.5% hyaluronan inhibits basal cell carcinoma, actinic keratosis, and murine colon-26 growth in vivo. colon-26 tumor growth was preceded by angiogenesis and reduced apoptotic and mitotic indices. Diclofenac reduced proliferation and viability in vitro, and stimulated apoptosis. Hyaluronan inhibited proliferation and viability at 1 mg/ml but was inactive below this level. Topical application of diclofenac inhibited tumor prostaglandin synthesis and retarded angiogenesis and tumor growth (ratio of treatment:control, 0.174). The mitotic index remained unaltered in vivo, whereas the apoptotic index and necrosis were increased. Topical vehicle exhibited slight antitumor and antiangiogenesis activity. The substantial quantities of diclofenac delivered locally in hyaluronan may exhibit antitumor activity in similar fashion to those seen in vitro and explain its clinical efficacy.

Proteoglycan degrading activity in granulomatous inflammation: comparison between the C57b1/6 and C57bg/bg mouse

OBJECTIVE AND DESIGN

Proteoglycan (GAG) and collagen are lost from cartilage juxtaposed to murine granulomatous tissue in both control and C57bg/bg (elastase deficient mice). The objective was to extract and characterise proteoglycan degrading activity within granulomas of both strains.

MATERIALS

15 animals (female C57b1/6 and C57bg/bg mice) per group were used.

TREATMENT

Cotton-wrapped rat femoral head cartilages were implanted subcutaneously into the dorsum of the mice and the granulomas excised fourteen days later.

METHODS

Granuloma and granuloma cell-granule preparations were fractionated within a detergent-based buffer and tested for their abilities to degrade cartilage in vitro in the presence and absence of enzyme inhibitors. Elastase and cathepsin G activities were also assessed using specific substrates. Statistical significance was calculated using Student's t-test.

RESULTS

Extracts from both strains induced the loss of cartilage GAG. This was correlated with cathepsin G activity (r = 0.96) and was inhibited by a specific cathepsin-G inhibitor (95%, p < 0.001), but not specific elastase or metalloproteinase inhibitors. Elastase activity but not that of cathepsin G was absent in the beige mice, whilst both enzymes were active in the controls.

CONCLUSIONS

It appears that neutrophil cathepsin G may play an important role in the degradation of cartilage proteoglycan in the murine cotton-pellet granuloma in both C57b1/6 and C57bg/bg.

[The effect of x-rays on experimental arthritis in the rat]

AIMS

We investigated the therapeutic efficacy of low doses of X-rays on different in-vivo models of monoarticular arthritis which have been developed for the investigation of anti-inflammatory drugs.

MATERIAL AND METHODS

Zymosan or heat-inactivated mycobacterium tuberculosis was injected into 1 knee joint of Wistar rats to produce, via different pathogenetic mechanisms, an acute monoarticular arthritis. Five days later, the amount of joint swelling, bone destruction and cartilage catabolism were measured. Immediately after arthritis induction, the knees were irradiated with a single dose of 5 Gy or with 4 daily fractions of 1 Gy.

RESULTS

X-irradiation with daily doses of 1 Gy significantly reduced bone loss and cartilage degradation in Zymosan-induced arthritis and joint swelling in mycobacterium tuberculosis induced arthritis. However, a single high radiation dose significantly increased bone loss in mycobacterium tuberculosis induced arthritis.

CONCLUSIONS

These data confirm the hypothesis of an anti-inflammatory effect of low radiation doses which so far has been based only on clinical experience. By using an established model of monoarticular arthritis we have now the opportunity to study the mechanism of the anti-inflammatory radiation effect in comparison to that of anti-inflammatory drugs. This way, we hope to provide a scientific basis for the use of radiotherapy in various painful degenerative joint disorders.

The pharmacological modulation of angiogenesis in chronic granulomatous inflammation

Angiogenesis is required for the progression of chronic inflammation, and agents that alter it can affect the development of inflammation and the consequent tissue destruction. However, in vivo quantification of neovascularization and its modulation by angiostatic and angiogenic agents is difficult. Studies have relied on reported effects of drugs on embryonic and tumor vasculature to infer angiomodulatory actions. We have characterized a vascular casting method that incorporates carmine in gelatin. Vascularity expressed as micrograms dye/mg dry tissue (vascularity index, V.I.) was studied in the murine chronic granulomatous air pouch. Carmine was retained within the vasculature by gelatin, and its content increased before the granulomatous tissue, resulting in a V.I. peak at 5 days, regression and a second peak over 14 to 28 days. The modulation of prostaglandin synthesis, plasma exudation and vasomotor tone showed that the carmine V.I. remained unaffected, unlike Evans blue, illustrating independence from acute inflammatory processes such as vasomotor tone and plasma exudation. The angiogenic stimulus p.o. heparin increased the V.I., whereas a sub-anti-inflammatory dose of cortisone with 1000 U heparin reduced it. Higher doses of heparin overcame this. The potent angiostatic steroid tetrahydrocortisol significantly reduced the V.I. in the absence of heparin. Cortisone exhibited independence from heparin on topical administration in hyaluronan. Dexamethasone inhibited granulomatous tissue development with a resulting increase in V.I. These observations indicated the differential effects of angiostatic and anti-inflammatory steroid activity. The pharmacological modulation of angiogenesis in inflammation can therefore be quantified.

Angiostasis and vascular regression in chronic granulomatous inflammation induced by diclofenac in combination with hyaluronan in mice

Angiostasis and vascular regression in chronic granulomatous inflammation was assessed in mice induced with diclofenac in combination with hyaluronan. The local injection of 0.1 mL HYAL EX-0001 (0.18% diclofenac in 2.5% hyaluronan) reduced granulomatous development after six days treatment from 150.4 +/- 13.8 (0.18 saline) to 117.1 +/- 17.8 mg (dry weight, n = 10), but not significantly when compared with 0.1 mL 2.5% hyaluronan alone or diclofenac in 0.1 mL saline. Diclofenac administered in saline had no significant effect when compared with saline control. The vascular density, expressed as carmine content per mg dry weight tissue, in those animals treated with HYAL EX-0001 was also significantly reduced to 5.27 +/- 0.55 micrograms mg-1 (P < 0.1, n = 10) when compared with saline control (7.99 +/- 1.0), hyaluronan alone (7.20 +/- 1.0), and diclofenac in saline. (7.36 +/- 1.28). A similar profile of activity was seen on topical application except that all treatments did not affect granulomatous tissue development. On therapeutic dosing of mice daily with HYAL EX-0001 from day 7 after induction of the granulomatous tissue, the granulomatous tissue development was dramatically reduced from 111.67 +/- 4.40 mg (n = 14 on day 7) to 60.23 +/- 7.22 (P < 0.001, n = 8 on day 14) and 54.98 +/- 7.88 (P < 0.001, n = 8 on day 21). HYAL EX-0001 after 14 days of application significantly reduced granulomatous tissue mass when compared with the hyaluronan-dosed control on day 21 (89.58 +/- 7.49, P = 0.01, n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Sex differences in inflammation induced cartilage damage in rodents. The influence of sex steroids

OBJECTIVE

To investigate sex differences in granulomatous inflammation and its effects upon articular cartilage and to assess the potential role of sex steroids in the process.

METHODS

The cotton-pellet cartilage implant model was used with male and female mice in the presence and absence of gonadectomy and hormone replacement. The effects of granulomatous tissue upon articular cartilage was assessed and tissue content of interleukin 1 (IL-1) was determined. The expression of sex hormone receptors in inflammatory tissue was investigated by immunocytochemistry.

RESULTS

Female mice showed a higher ability than males to degrade cartilage irrespective of the sex of the cartilage implanted. Gonadectomy resulted in a significant acceleration of cartilage damage in both sexes, which was reverted by estrogen replacement in females and androgen replacement in males. Female granulomata had significantly higher IL-1 content than those from males. Gonadectomy was associated with an increased IL-1 content in males but not in females, the effects being abolished by androgen replacement in males. Estrogen and androgen receptors were identified in inflammatory cells from the granulomatous tissue.

CONCLUSION

Our data demonstrate that sex hormones affect inflammation induced cartilage degradation in male and female mice probably through the modulation of cytokine production and release in the granulomatous tissue. Further investigation on the effects of sex steroids in inflammation induced cartilage degradation may help elucidate their pathogenic role and therapeutic potential in human disease.

Inhibition of interleukin 1 beta induced rat and human cartilage degradation in vitro by the metalloproteinase inhibitor U27391

Interleukin 1 induced proteoglycan loss from cartilage in vitro was prevented by a biochemical inhibitor of metalloproteinase activity. The inhibitor also partially relieved the inhibition of proteoglycan synthesis caused by interleukin 1. The loss of glycosaminoglycan by rat and human femoral head cartilage in response to human recombinant interleukin 1 beta (rhIL-1 beta) was established, and the modulation of this loss by the metalloproteinase inhibitor U27391 was investigated. Rat femoral head cartilage consistently lost glycosaminoglycan in response to rhIL-1 beta whereas only a proportion (30%) of normal human femoral head cartilage did so. Concentrations of 10-100 mumol/l U27391 inhibited the action of rhIL-1 beta on rat femoral head cartilage, reversing both the loss of glycosaminoglycan and the inhibition of glycosaminoglycan synthesis. U27391 also prevented the reduction in glycosaminoglycan content of those human femoral head cartilage explants responsive to rhIL-1 beta. Metalloproteinase inhibition therefore prevents rhIL-1 beta induced glycosaminoglycan loss by rat and human femoral head cartilage, suggesting that inhibitors of such enzymes may prove to be of therapeutic benefit in erosive diseases in humans.

Some observations on the pharmacology of 'deep-heat', a topical rubifacient

A topically applied rubifacient delivered by aerosol (Deep-Heat) was studied. After spray application to the forearms of volunteers, without massage, the erythema produced was measured by thermography and correlated with the concentration of 2 salicylate components of the mixture found in local and systemic venous blood. Maximum erythema occurred at about 30 minutes, while blood salicylate levels were maximal between 20 and 30 minutes after application. Methyl salicylate was absorbed before ethyl salicylate. Over the time period of the erythematous response oxygen levels in local venous blood were raised. Finally, platelets collected from venous blood draining from the sprayed site, when induced to clump by the addition of arachidonic acid in an aggregometer, showed increased resistance to clumping when compared with control cells. The mechanism of these observed phenomena and the mode of action of the constituents of Deep-Heat are discussed.