Interactions between corticosteroids and a mucopolysaccharide containing tissue extract on mucopolysaccharide metabolism of fibroblast cultures

The pathogenesis and prevention of atherosclerosis

Most measures taken to prevent atherosclerosis still aim at lowering the cholesterol content of the plasma lipoproteins by dietary and pharmacological means. This approach has only proved successful to a limited extent. Diseases secondary to atherosclerosis are still the commonest cause of death in western industrialized countries. As all metabolic processes are regulated by opposing processes of equilibrium, i.e. by processes directed towards performance and recovery, we asked ourselves whether the fatty degeneration and sclerosis of the arteries could be causally related to a continuous dysregulation of these processes. We consider this to be the case, with a continuous deficiency of glycosaminoglycans (heparin, heparinoids) on the endothelial surface of the vessels. Numerous studies indicate that in the case of thinning of the anionic glycosaminoglycan film on the endothelial surface, the lipoprotein-lipase and antithrombin III activity induced by heparin is reduced, as result of which hyperlipoproteinaemia and increased tendency to thrombosis can only by compensated for to an inadequate extent. The formation of glycosaminoglycans is a characteristic of all mesenchymal cells, whereby the exogenous introduction of glycosaminoglycans into the extracellular space is of decisive importance for adequate glycosaminoglycan synthesis. Since Engelberg reported outstanding results obtained with heparin injections in the prevention and treatment of atherosclerotic disorders of the cardiac circulation, we considered it appropriate to use the well-proven dietary supplement of glycosaminoglycans in rheumatology, in the treatment of arthrosis, as well as in the prevention and treatment of atherosclerosis.

Anti-rheumatic drugs and cartilage

In this chapter an attempt has been made to draw together the known biology of cartilage and some of the mechanisms thought to be responsible for its failure in arthritis. The picture is far from complete but we are now in a good position to use this information to help appraise the pros and cons of the wide range of drugs now available to treat articular disorders. For convenience, these drugs were classified as NSAIDs, corticosteroids and chondroprotective agents. The influence of each of these classes on the metabolism of cartilage was examined in the light of published laboratory and clinical studies. It has been clearly shown that not all NSAIDs are the same. While many of the older drugs provided no benefit to cartilage metabolism, and in some instances suppressed it, the more recently discovered molecules appear to be free of these undesirable effects. Tiaprofenic acid, diclofenac and piroxicam emerged as drugs with little or no harmful effects on cartilage metabolism when used at concentrations within the human therapeutic range. For all NSAIDs, their potential effects on cartilage must be weighed against their respective anti-inflammatory potency, half-life, and effects on the gastric mucosa and other tissues. Other chapters in this book have addressed these important problems. The long-acting corticosteroids, betamethasone and triamcinolone hexacetonide, also appear to offer some benefit in the management of OA; however, as in RA, their use should be restricted to short-term applications. In terms of cartilage metabolism the chondroprotective agents pentosan polysulphate, Arteparon and Rumalon have been the most extensively studied class of drugs. While the laboratory studies have provided convincing evidence of their chondroprotective efficacy, it has been difficult to prove this clinically. This dichotomy of opinion (laboratory versus clinical) stems largely from the inadequacy of the methodologies currently available for the objective clinical assessment of patient response to anti-rheumatic drug therapy. With the advent of nuclear magnetic resonance imaging techniques and monoclonal antibodies to detect specific proteoglycan breakdown fragments in synovial fluid and plasma, the prospects for a unified research approach for the evaluation of these agents may now be possible.

The mode of action of a glycosaminoglycan-peptide-complex (Rumalon) on articular cartilage of the rat in vivo

Quantitative ultrastructural morphometry and autoradiography of articular cartilage were used to assess in 3 months old rats the effects of in vivo administration of dexamethasone alone or in combination with a glycosaminglycan-peptide-complex (GAGPC). Dexamethasone treatment (3 mg/kg week for three weeks) induced a decrease of 35S-sulphate incorporation in cartilage and ultrastructural changes of articular chondrocytes, mainly characterized by an increase in cell mortality rate, a decrease in length of endoplasmic reticulum, in the number of Golgi bodies and in mitochondrial pool and size. These autoradiographic and ultrastructural changes were reversed or prevented when GAGPC was administered concomitantly with dexamethasone. These results show that the modifications measured by quantitative ultrastructural morphometry of chondrocytes are consistent with changes in biosynthetic functions and that the GAGPC protects cartilage from the inhibitory effects of corticoids.