Passive transfer of allergic encephalomyelitis in rats: a tool for drug mechanism studies and detecting late-acting immunosuppressants.

1. A strategy is described for evaluating drugs against different phases in the development of an auto allergic disease, experimental allergic encephalomyelitis. It is based on a cell transfer technique whereby the disease is passively transferred with lymphoid cells from actively immunized donor rats to normal syngeneic rats = passive recipients. Drugs may be applied in vivo to either the cell donors or the cell recipients or to cells in vitro whilst in transit; their efficiency being determined by the severity of the passive disease (weight loss, paralysis) in the recipients. 2. Examples are given illustrating the application of these techniques to: (a) evaluating the lymphocyte-deactivating activity of various nitrogen mustards in vitro; (b) recognizing drugs, e.g. gold derivatives, clofazimine, etc. that are not conventional immunosuppressant (or cytostatic) agents which, when given to the recipient animals, may prevent the expression of the adopted disease; (c) comparing some known immunosuppressants for potency, duration of action, etc.; (d) demonstrating the versatility of cycloleucine, ICI-47,776, etc. 3. Some merits of the strategy are discussed vis a vis using the local graft-versus-host reaction in rats to search for new drugs.

Paracetamol (acetaminophen): a blessing or a hidden curse?

This Journal has recently published a splendid review of all you need to know about paracetamol (Graham et al. 2013), an analgesic widely used in the long-term management of arthritis. It clearly presents the science and hard facts. This commentary, by contrast, discusses some aspects of the metapharmacology of paracetamol; particularly by asking questions of how we might extract more benefit and suffer less adverse reactions when using this analgesic in the context of non-transient inflammation. As both a drug and a toxin, paracetamol exemplifies how beneficial and/or deleterious responses may be conditioned by circumstances (disease stress, nutritional status, fasting, etc.).

Synthesis and anti-inflammatory properties of some aromatic and heterocyclic aromatic curcuminoids.

A variety of novel aromatic and heterocyclic aromatic curcuminoids were synthesised, characterised and their anti-inflammatory activities (AIA) determined in vivo. Some of these compounds also were tested for inflammatory mediator production. The AIA of the main representatives of these compounds were assessed by oral administration to female Wistar rats using (a) acute carrageenan-induced paw oedema, (b) chronic adjuvant arthritis (therapeutic mode), and (c) anti-pyretic activity assessed in the yeast pyrexia. Gastric ulceration was determined in pre-inflamed rats. Natural curcumin showed modest aspirin-like anti-inflammatory activity which was enhanced when co-administered with the PGE(1) analogue misoprostol as a synergist. In contrast, four novel curcuminoids (RK-97, RK-103, RK-104 and RK-106) in which the bis-methoxy-phenyl group of curcumin was replaced with bis-dimethoxybutenolidyl-(ascorbate), bis-naphthyl, and bis-furanyl derivatives, respectively, had potent activity in the anti-arthritic assay with little gastric or systemic toxicity, compared with the vehicle-treated controls. Of the curcuminoids the furan RK-106 was the only compound to inhibit production of TNFα and IL-1ß in a monocytic cell-line THP-1 in vitro. The inactivity of RK-106 on the production of PGE(2) may be related to its absence of gastrotoxicity. None of the curcuminoids exhibited anti-pyretic activity and this may also be related to its insensitivity to PGE(2). Thus, these novel curcuminoids, such as RK-106, may warrant the development of new low gastro-toxic anti-inflammatory agents with selective inhibitory activity of cytokine inflammatory mediators.

Therapeutic gold. Is it due for a come-back?

The historical use of metallic gold and gold complexes in medicine is briefly outlined. Currently, there is a large body of opinion that they belong to another age, are no longer relevant and that there are more-than-adequate successors to replace them. Nevertheless some challenging questions remain: (1) Should we now ignore their remarkable properties for ameliorating rheumatoid arthritis, even inducing remissions and for preventing arthritis development in animals? (i) What mechanisms underlie their clinical activity? (ii) Can some of the adverse effects of traditional therapy with gold-thiolate complexes be reduced/prevented by either modifying their formulations, or by using some of their bio-transformation products at much lower doses? (iii) Are they equivalent, perhaps even superior to biological DMARDs (anti-TNFalpha, anti-IL-1), and if so, more cost effective?

Aurocyanide, dicyano-aurate (I), a pharmacologically active metabolite of medicinal gold complexes.

The aurocyanide anion, Au(CN) (2) (-) , is a human metabolite of several anti-rheumatic gold complexes containing monovalent gold (I) bound to a sulphur ligand. This article reviews some of the chemical and pharmacological properties of this intriguing metabolite, and reports its anti-arthritic and anti-inflammatory activity in rats. Au(CN) (2) (-) is generated from the therapeutic gold complexes by small amounts of hydrogen cyanide, HCN, produced from thiocyanate, SCN(-), by myeloperoxidase (MPO) an enzyme in neutrophils which normally produces hypochlorite, OCl(-). Thus, Au(CN) (2) (-) is formed at sites of inflammation where activated neutrophils are present. This includes atherosclerotic lesions as well as inflamed joints. MPO also oxidises Au(CN) (2) (-) to Au(III) complexes such as Au(CN) (4) (-) .Au(CN) (2) (-) is normally a very stable monovalent gold complex. In a biological context, only low concentrations are ever present at both extracellular and intracellular sites. However, Au(CN) (2) (-) produced locally may facilitate the cellular uptake and hence the therapeutic and toxic effects of gold drugs. Au(CN) (2) (-) may also be involved in a redox cycle where Au(CN) (2) (-) is oxidised to Au(CN) (4) (-) which is, in turn, reduced back to Au(CN) (2) (-) by endogenous thiols. There are still many questions to be resolved concerning Au(CN) (2) (-) including its intrinsic toxicity and the extent to which it may contribute to the overall anti-arthritic activities of the gold-thiolates from which it is formed in vivo.

Colloidal metallic gold is not bio-inert.

Metallic gold (Au degrees ) is a likely biotransformation product of monovalent gold, Au(I) whenever it is dissociated from in vivo ligands, Au degrees being formed either by bioreduction or by spontaneous dismutation (with co-production of trivalent gold). This review discusses the preparation and some biologically relevant properties of colloidal metallic gold (CMG) in its nano-particulate form. Tyndall's purple, a well characterised preparation of CMG, shows potent anti-arthritic activity in rats, approximately 10(3) times that of sodium aurothiomalate (Myocrysin). Even more remarkable is its broader spectrum of action in rats compared to this classic DMARD.

Adjuvant arthritis 50 years on: The impact of the 1956 article by C. M. Pearson, 'Development of arthritis, periarthritis and periostitis in rats given adjuvants'.

The Science Citation Index (Web of Science) has now accumulated over 700 citations to this report published in Proc Soc exp Biol Med 1956; 91: 95-101, including several in 2006. This memoire is a tribute to its author for revealing the opportunities for so much subsequent research in experimental pharmacology and toxicology. For half a century, the adjuvant disease in rats has enormously aided research on drugs to control arthritis and other chronic inflammatory disorders. The adjuvant also triggers many systemic responses beyond the articular tissues. So we are given simultaneously a window to explore the converse phenomenon: namely, how a chronic disease can affect drug efficacy and toxicity. This phenomenon has been variously described as patho-pharmacodynamics, conditional pharmacology/toxicology and 'a right nuisance' ! Nevertheless it has enormous heuristic value for clinical therapeutics.

Paracetamol [acetaminophen]-induced gastrotoxicity: revealed by induced hyperacidity in combination with acute or chronic inflammation.

Paracetamol is regarded as a relatively safe drug in the gastro-duodenal region of humans but recent epidemiological investigations have suggested that at high doses there may be an increased risk of ulcers and bleeding. To investigate the possibility that inflammatory conditions and gastric acidity may play a role in potentiating development of gastric mucosal injury from paracetamol in rats (as noted previously with various non-steroidal anti-inflammatory drugs) we studied the gastric irritant effects of paracetamol and some phenolic and non-phenolic analgesics and antipyretics in rats with adjuvant or collagen II induced arthritis or zymosan-induced paw inflammation and given 1.0 ml hydrochloric acid (HCl) 0.1 M and/or an i. p. injection of the cholinomimetic, acetyl-beta-methyl choline chloride 5.0 mg/kg. Gastric lesions were determined 2 h after oral administration of 100 or 250 mg/kg paracetamol or at therapeutically effective doses of the phenolic or non-phenolic analgesics/antipyretics. The results showed that gastric mucosal injury occurred with all these agents when given to animals that received all treatments so indicating there is an adverse synergy of these three factors, namely: (i) intrinsic disease; (ii) hyperacidity; and (iii) vagal stimulation for rapidly promoting gastric damage, both in the fundic as well as the antral mucosa, for producing gastric damage by paracetamol, as well as the other agents. Removing one of these three predisposing factors effectively blunts/abolishes expression of this paracetamol-induced gastrotoxicity in rats. These three factors, without paracetamol, did not cause significant acute gastropathy.

Arthritic disease suppression and cartilage protection with glycosaminoglycan polypeptide complexes (Peptacans) derived from the cartilage extracellular matrix: a novel approach to therapy.

Molecular fragments of cartilage are antigenic and can stimulate an autoimmune response. Oral administration of type II collagen prevents disease onset in animal models of arthritis but the effects of other matrix components have not been reported. We evaluated glycosaminoglycan polypeptides (GAG-P) and matrix proteins (CaP) from cartilage for a) mitigating disease activity in rats with collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) and b) stimulating proteoglycan (PG) synthesis by chondrocytes in-vitro. CIA and AIA were established in Wistar rats using standard methods. Agents were administered orally (10-200 mg/kg), either for seven days prior to disease induction (toleragenic protocol), or continuously for 15 days after injecting the arthritigen (prophylactic protocol). Joint swelling and arthritis scores were determined on day 15. Histological sections of joint tissues were assessed post-necropsy. In chondrocyte cultures, CaP + / - interleukin-1 stimulated PG biosynthesis. CaP was also active in preventing arthritis onset at 3.3, 10 or 20 mg/kg in the rat CIA model using the toleragenic protocol. It was only active at 20 and 200 mg/kg in the CIA prophylactic protocol. GAG-P was active in the CIA toleragenic protocol at 20 mg/kg but chondroitin sulfate and glucosamine hydrochloride or glucosamine sulfate were all inactive. The efficacy of CaP in the rat AIA model was less than in the CIA model. These findings lead us to suggest that oral CaP could be used as a disease-modifying anti-arthritic drug.

Anti-TNF-alpha therapy for chronic inflammation: reconsidering pentoxifylline as an alternative to therapeutic protein drugs.

Pentoxifylline is a useful inhibitor of TNF-alpha production, thus resembling anti-inflammatory corticosteroids. The combination of pentoxifylline with Lyprinol is an effective treatment for chronic inflammation in rats, in this respect mimicking low dose prednisone with Lyprinol.

Treating inflammation: some (needless) difficulties for gaining acceptance of effective natural products and traditional medicines.

The quality of so-called 'natural medicines' is extraordinarily variable. Lack of resolute pharmacological assays contributes to this hiatus. More stringent evaluation of anti-inflammatory and anti-pyretic activities in rats can help resolve some of the uncertainties surrounding (a) preparations of some herbal products including so-called 'nature's aspirin' (e.g. willowbark, ginger), cat's claw, celery seed, etc., and (b) some animal lipids (e.g. Lyprinol(R) (NZ Mussel), emu and fish oils). These animal products can be a remarkable resource for supplementing conventional/allopathic therapy for inflammatory disease, e.g. providing lipoxygenase inhibitors. Beyond the verifiable science, the healing professions and the general public still need to examine more carefully criteria for QUALITY(S) in any alternative medicine-to ensure the good (= both reputations and products) are not destroyed by the bad-in essence counteracting Gresham's Law which states: the bad tends to displace the good.

Combination anti-inflammatory therapy: synergism in rats of NSAIDs/corticosteroids with some herbal/animal products.

A useful function of any complementary medicine is to supplement some of the benefits from other treatment modalities. In rats, extracts from Indian celery seed and the NZ green-lipped mussel are powerful nutraceuticals that (i) amplify the potency of salicylates and prednisone for treating pre-established chronic inflammation (arthritis, fibrosis) and (ii) reduce the steroid's gastrotoxic and lymphopenic side effects. Such combinations might also be useful for treating inflammatory components of (a) osteoarthritis caused by microcrystalline hydroxyapatite (BCP) and (b) pseudo-gout, associated with calcium pyrophosphate crystals; that are usually refractory to monotherapy.

Lyprinol: anti-inflammatory and uterine-relaxant activities in rats, with special reference to a model for dysmenorrhoea.

Lyprinol exhibits anti-inflammatory activity distinct from that of most NSAIDs, controlling chronic but not acute inflammation. Unlike Cox-1 inhibitors (aspirin, meclofenamic acid) it is not gastro-toxic. Predosing rats with Lyprinol can modify both (i) the spontaneous and (ii) the oxytocin-induced contractions of the uterus. In humans there is anecdotal evidence that Lyprinol can relieve dysmenorrhea. This report explores the concept that the uterotrophic actions of Lyprinol are conditioned by: the intrinsic profile of estrogenic hormones and progestagens and, certain extrinsic stimuli. Evidence from in vitro studies indicates that Lyprinol is not a smooth muscle relaxant and that its uterotrophic mechanism is not that of a cyclo-oxygenase inhibitor, but may mimic that of a leukotriene receptor antagonist.

Effect of ion pairing with alkylamines on the in-vitro dermal penetration and local tissue disposition of salicylates.

Hydrophilic ionic drugs can be rendered lipophilic by ion-pair formation with hydrophobic counter-ions. This study examines the value of forming ion pairs between anionic salicylate and a series of amines as model cationic counter-ions to facilitate topical delivery and skin penetration. The in-vitro translocation of salicylate ions from a nonaqueous vehicle through human epidermis was estimated in the presence or absence of amines. The distribution into, and accumulation of the salicylate ion in various tissues following topical application to anaesthetised rats were also investigated. Although the epidermal permeation constants of the salicylate-amine ion pairs were lower than that of salicylate itself (enhancement ratios: 0.74-0.87), salicylate retention and localisation in the underlying rat tissues increased in the presence of some of the counter-ions studied. Salicylate concentrations (microg (g tissue)(-1)) in the dermis were 877.2+/-78.6 for salicylate alone and 1098+/-121.9-2586+/-332.5 for salicylate-amine ion pairs. The levels of salicylate in tissues up to the top muscle layer were 1.2-3.7-fold higher in the presence of the counter-ions. It is concluded that, although amine counter-ions have the ability to influence the penetration of salicylate, in-vitro permeability studies do not reflect the in-vivo increases in tissue concentrations resulting from probable changes in systemic clearance.

Non-NSAID over-the-counter (OTC) remedies for arthritis: good, bad or indifferent?

This overview looks at some of the issues involved with the ever-increasing availability of marketed non-prescription products, specifically claiming to treat the pain and inflammation of arthritis and other musculoskeletal problems.The question of whether the buyer is getting (any) value for their money cannot be answered without considering several key issues. These include: (a) reliability of claims; (b) placebo effect (but for how long?); (c) reliability of composition, and reproducibility (especially of natural products); (d) general safety; (e) interactions with other medications; (f) honest labelling (in the absence of stricter guidelines).A particularly difficult problem is to know how to recognise a 'drug of choice', particularly for such a multi-faceted disease as chronic arthritis, when there is so little information about the actual pharmacology/potential toxicity of these OTC products in the standard drug compendia and other readily available reference texts.This grey area can only be illuminated by (i) further introduction (and enforcement) of adequate standards/quality controls for products offered OTC; (ii) earliest prosecution of clinical trials to supercede unverified testimonial claims; (iii) appropriate funding to research/establish basic pharmacology of the active principles.In summary, more research, more regulation, and more realistic investment will be required to dispel present uncertainty about which non-NSAID drugs/nutriceuticals are indeed effective against arthritis/other forms of inflammation, and which are not.

Concerning the anti-arthritic action of cetyl myristoleate in rats: an interim report.

The proposed arthro-preventive action of cetyl myristoleate, an OTC product sold as a nutritional supplement, could not be confirmed, using an almost identical bioassay (adjuvant-induced polyarthritis in rats) as that described in the original report (Diehl and May, 1994) with the same, and 3 other, dosing schedules.

Over the counter (OTC) oral remedies for arthritis and rheumatism: how effective are they?

BACKGROUND: Increasingly patients resort to alternative remedies for arthritis and rheumatism, perhaps partly impelled by reports of toxicities from prescribed non-steroid anti-inflammatory drugs (NSAID). There is uncertainty about whether the most common alternative treatments provide relief or may cause adverse reactions. AIM: To ascertain the validity of manufacturers' claims permitted by the Therapeutic Goods Administration (TGA) in Australia for a range of self-medication products to treat the pain and inflammation of arthritis, available in local pharmacies, supermarkets or by mail order and in other countries. METHODS: OTC products were administered orally to rats in standard assays for suppressing experimental arthritis and fever and for determining potential gastrotoxicity. RESULTS: The three NSAIDs available OTC were efficacious but gastrotoxic. Of the 37 herbal formulations examined, seven were as effective as ibuprofen in the anti-arthritic assay without causing gastric bleeding. Five of the 10 animal-sourced products tested were also effective without evident toxicity. Within a certain class of product, e.g. celery seed extracts or dried mussel preparations, efficacies ranged from almost zero to highly effective. CONCLUSIONS: Consumers currently have no guide to the likely efficacy of TGA-approved remedies. Quality control is urgently needed to justify the veracity of TGA-permitted and other claims on product labels.