Evaluation of potential antirheumatic drugs in vitro using lymphocytes and epithelial cells. The selective action of indoxole, methyl glyoxal and chloroquine

Sequential Sonogashira/intramolecular aminopalladation/cross-coupling of ortho-ethynyl-anilines catalyzed by a single palladium source: rapid access to 2,3-diarylindoles

We have developed a practical and efficient one-pot protocol for the synthesis of 2,3-diarylindoles via Pd-catalyzed bis-arylative cyclization of various o-ethynylanilines with aryl iodides. Mechanism studies showed that a Pd-catalyzed Sonogashira reaction took place firstly, giving an internal alkyne intermediate, which subsequently underwent intramolecular aminopalladation/cross-coupling to give access to 2,3-diarylindoles. The present methodology exhibits a broad substrate scope, producing various 2,3-diaryl indoles bearing two different aryl groups.

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.

Anti-inflammatory glucocorticoid drugs: reflections after 60 years

This review considers the problem of the serious concomitant side effects of powerful anti-inflammatory drugs modelled upon the principal human glucocorticoid hormone, cortisol. The very nature of the original bio-assays to validate their cortisol-like hormonal and anti-inflammatory activities ensured that pleiotropic toxins were selected for clinical studies. Other complicating factors have been (1) considerable reliance on bio-assays conducted in laboratory animals that primarily secrete corticosterone, not cortisol, as their principal anti-inflammatory adrenal hormone; (2) some differences in the binding of xenobiotic cortisol analogues (vis á vis cortisol) to transport proteins, detoxifying enzymes and even some intra-cellular receptors; (3) the "rogue" properties of these hormonal xenobiotics, acting independently of--but still able to suppress--hormonal mechanisms regulating endogenous cortisol; and (4) problems of intrinsic/acquired "steroid resistance", diminishing their clinical efficacy, but not necessarily all their toxicities. The rather gloomy conclusion is that devising new drugs to reproduce the effect of multi-potent hormones may be a recipe for disaster, in contexts other than simply remedying an endocrine deficiency. Promising new developments include "designed" combination therapies that allow some reduction in total steroid doses (and hopefully their side effects); sharpening strategies to limit the actual duration of steroid administration; and resurgent interest in searching for more selective analogues (both steroidal and non-steroid) with less harmful side effects. Some oversights and neglected areas of research are also considered. Overall, it now seems timely to engage in some drastic rethinking about (retaining?) these "licensed toxins" as fundamental therapies for chronic inflammation.

Role of lymphocytes in non-immune experimental inflammation

The role of lymphocytes in acute, non-immune inflammation has been studied in rats. Using drug-induced leucopenia and cell transfer studies it was found that the reduced carrageenin paw oedema in leucopenic rats could be restored by a specific subclass of lymphocytes distinct from T and B lymphocytes. The inflammatory effect of these lymphocytes appears to be mediated by a factor, the release of which is inhibited by steroidal and non-steroidal anti-inflammatory drugs and antilymphocyte sera.

Articular cartilage, blood serum glycosaminoglycans and glycoproteins in osteoarthritis deformans

Glycosaminoglycans in articular cartilage from human femoral heads have been isolated and fractionated by means of a cellulose microscale technique. The glucosaminoglycans have been identified by different procedures as keratan sulphate, hyaluronic acid, heparitin sulphate, chondroitin 4-sulphate, chondroitin 6-sulphate and dermatan sulphate. Osteoarthritic cartilage showed a significant reduction of dermatan sulphate, chondroitin 6-sulphate, keratan sulphate and heparitin sulphate. The content of glycoprotein carbohydrate components in the cartilage (neuraminic acid derivatives, hexoses, 6-deoxyhexoses) also appeared to be reduced. It has been shown that chondroitin 4-sulphate, keratan sulphate and dermatan sulphate content was considerably increased in osteoarthritic serum. Among serum glycoprotein carbohydrate constituents only the content of 6-deoxyhexoses was slightly increased.

Lymphocyte surface poisons: disulfides and thiolsulfonates

Eight disulfides (I-VIII) and a thiolsulfonate (IX) were promising blocking agents of lymphocytes in graft-versus-host reactions (GvHR) without comensurate intracellular effects. The blocking effects were assayed through inhibition of the local GvHR after parental lymphocytes had been incubated with agents at suitable concentrations and then inoculated into F1 hybrid offspring. The intracellular effects were assessed beforehand by measuring the inhibition of [6-3H]thymidine incorporation by lymphocytes in the presence of a wide range of concentrations of agents. Concentration levels which induced no greater than approx. 50% inhibition of the [6-3H] thymidine incorporation were considered to reflect sufficiently small intracellular effects and were used for the subsequent GvHR comparisons. Cellular survival always was 90% or more for the GvHR tests (unless stated otherwise), even when inhibition of thymidine incorporation was as high as 50%; hence the thymidine data are useful not only as guides for dose levels in the GvHR but also as leads to new agents that may show immunosuppressive or anti-leukemic activity through intracellular effects. Structural specificity of the active compounds as cell-surface poisons is evidenced by little or no activity (less than 30% inhibition of GvHR) of 28 other disulfides, 2 trisulfides, 2 Bunte salts, and 8 other thiolsulfonates. Active agents may owe this function to replacement of the H of SH in cell-surface thiol receptors by an SR group. Glutathione did not significantly inactivate agents, probably because the products of reaction also are active disulfides. When two agents (III, IX) were given orally or intraperitoneally to F1 hybrid recipients of untreated parental cells, doses of 10--15 mg/kg produced a GvHR inhibition of 17--53%.

About some possible anti-inflammatory properties of various membrane permeant agents

Non steroidal anti-inflammatory drugs uncouple mitochondrial oxidative phosphorylation. They are membrane permeant agents. They also inhibit nucleic acids synthesis in lymphoid cells. Three antibiotics (valinomycin, gramicidin A, alamethicin) and one cyclic polyether (dibenzo-18-crown-6) which are potent membrane permeant agents and good uncouplers are demonstrated to inhibit such a nucleic acids synthesis. This inhibition is largely dependent on the ionic composition of the incubation medium. It is suggested on the basis of some preliminary results that these drugs, which are non-acidic molecules, should be further investigated for potential anti-inflammatory properties.

Inhibition of enzymes by alkylsalicylic acids

5-n-Alkylsalicylates inhibited a variety of enzymes that transform acidic substances, viz. glucose-6-phosphate dehydrogenase, glyoxalase, xanthine oxidase, carbonic anhydrase and D-amino-acid oxidase. Inhibitory potency rose to a peak at the n-nonyl derivative. None of the tests were of value, either singly or in combination, as screening processes for anti-inflammatory activity. The comparable results with a trinitrobenzaldehyde reagent suggest that the various inhibitions arise by non-specific association of the drugs with arginine and lysine residues in proteins.

Identification of a bacterial growth inhibitors from HeLa cells: a ketoaldehyde

The growth-inhibiting factor found earlier in human cell cultures appeared to be a ketoaldehyde. An infrared spectral study of 2,4-dinitrophenylhydrazine derivatives suggested that the ketoaldehyde was 4-hydroxy-2-ketobutyraldehyde. The compound, when synthesized, gave the same DNPH derivatives as the natural substance.