Synthesis of glycosaminoglycan in adult human articular cartilage in organ culture from patients with rheumatoid arthritis

Quantitative assessment of the effect of 0.05% chlorhexidine on rat articular cartilage metabolism in vitro and in vivo

Wound infection remains a problem. Syringe and needle jet lavage of chlorhexidine gluconate 0.05% removed or killed 99.8% of contaminating bacteria within 1 minute in a wound model. In clinical use, however, possible toxicity to articular cartilage is a concern. In an established intact rat patella model in vitro, 1 minute of exposure to chlorhexidine 0.05% and chlorhexidine jet lavage did not significantly alter cartilage metabolism. A 1-hour exposure decreased metabolic activity. In vivo, a 30-minute exposure with or without rinsing produced no impairment of metabolic activity 6 weeks later, suggesting that cartilage has the potential for biological recovery. However, injecting and leaving chlorhexidine 0.05% in the joints was detrimental to the metabolic activity of the articular cartilage as assessed 6 weeks later. Thus, chlorhexidine gluconate 0.05% could be used on normal articular cartilage. Any potential damage from prolonged exposure can be avoided by rinsing after 1 minute.

Structural and biochemical abnormalities of articular cartilage in rheumatoid arthritis

Compared with normal cartilage, the water content, extraction yields, and capacity of 34SO4 incorporation, were found to be increased in articular cartilage from rheumatoid joints, which also synthesizes an increased proportion of low and middle density small size proteoglycans (PGs), enriched in dermatan sulfate. These small [35S]-PGs also possess longer glycosaminoglycan side chains and lack the ability to interact with hyaluronan. An altered pattern of PG synthesis of rheumatoid chondrocytes may contribute to cartilage damage in this condition.

Human rheumatoid arthritic cartilage and its neutral proteoglycan-degrading proteases. The effects of antirheumatic drugs

Measurements were made of the neutral proteoglycan-digesting protease activity in the cartilage matrix breakdown observed in the rheumatoid arthritic process. Normal knee (tibial plateau) cartilage specimens were obtained from 7 fresh cadavers and 29 cartilage specimens were obtained from 23 patients diagnosed as having rheumatoid arthritis (RA). The total neutral metalloproteoglycan-degrading enzyme (NMPE) activity in RA cartilages exhibited roughly an eightfold elevation over that of control subjects. The active form of the NMPE for diseased cartilage was higher than that observed for normal cartilage, but was not statistically different. A very low level of activity was detected for serine proteases and no variation was observed between normal and diseased cartilages. Data obtained from RA cartilages were also analyzed with respect to the relationship between enzyme activities and the patients' medications. Four groups of patients were then selected according to their drug treatments: S + G patients received steroid and gold therapy; S patients received steroids only; NS + NG patients did not receive steroid or gold therapy; G patients received gold therapy alone. The total NMPE activity for each of these groups remained at a very high level. The active enzyme activity measured in S + G and S patients was decreased to a level not different from that of normal controls. Specimens from NS + NG patients presented a significantly higher level of the active form of the enzyme (P less than 0.05) when compared with either normal controls, S + G, or S patients. No significant difference was noted in the level of serine protease activity between the RA cartilage and normal cartilage.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of synovial tissue on the synthesis of proteoglycan by the articular cartilage of young pigs

Explants of pig articular cartilage were grown in organ culture in the presence of synovial tissue; controls consisted of paired explants that were cultivated in isolation. To find whether the synovial tissue affected synthesis of sulfated proteoglycan by the cartilage, 35SO4 was added to the medium and its incorporation into the cartilage examined by both biochemical assay and autoradiography. The synovial tissue severely inhibited the uptake of 35SO4, but if the synovium was removed after 8 days cultivation and the cartilage was grown in isolation for a further 4 days, incorporation of 35SO4 equalled and sometimes surpassed that of controls which had been grown without synovium continuously for 12 days. Synovium did not prevent the formation of new cartilage on the cut surfaces of the explants, but it reduced the incidence of newly formed cartilage.

Effect of homologous synovial membrane on adult human articular cartilage in organ culture, and failure to influence it with D-penicillamine

Adult human articular cartilage has been maintained in organ culture for 8 days, and the culture medium, which was changed on alternate days, was pooled. Normal and rheumatoid cartilage was obtained from patients and 4 types of culture were prepared: (1) cartilage alone; (2) cartilage + D-penicillamine; (3) cartilage + homologous synovium; (4) cartilage, synovium, and D-penicillamine. The hexosamines and hexuronic acid were measured in the cartilage explants and in the medium. The quantity released was divided by the amount measured in the original cartilage explant and the different culture variables were compared. D-penicillamine did not alter the release of cartilage proteoglycan, but the addition of synovium did. The rheumatoid cartilage released significantly more proteoglycan than normal cartilage whether or not homologous synovium was present.

Somatomedin activity in synovial fluid from patients with joint diseases

The somatomedin activity in synovial fluids from 50 patients with a variety of joint diseases has been studied and compared with the activity in each of the patient's own serum and a standard reference serum (SRS). The porcine costal cartilage bioassay of Van den Brande and Du Caju (1974a) has been used with the isotopes 3H-thymidine and 35S-sulphate. Synovial fluids from most patients with post-traumatic and post-operative effusions, osteoarthritis and arthritis associated with psoriasis, Reiter's disease, and ankylosing spondylitis stimulated the synthesis of DNA and proteoglycans in cartilage. Synovial fluids from patients with rheumatoid arthritis either had impaired capacity to stimulate DNA synthesis, or they inhibited it; a similar, but less evident pattern was observed for proteoglycan synthesis. Some synovial fluids from patients with miscellaneous synovitides stimulated, while others inhibited cartilage metabolism. It is concluded that the synovial fluid from patients with rheumatoid arthritis and from some patients with miscellaneous synovitides contained an inhibitor(s) to DNA and possibly proteoglycan synthesis. The sera from nearly all the patients stimulated both DNA and proteoglycan synthesis, but the somatomedin potency ratios for serum in terms of SRS were generally less than 1.0. There was a significant inverse correlation between the serum somatomedin potency ratio and the age of the patient.

Organ culture of human articular cartilage: studies on sulphated glycosaminoglycan synthesis

An organ culture system is described for adult human articular cartilage obtained from joints after femoral head replacement operations. Cartilage slices maintain maximal viability for 2 days in culture as assessed by uptake of [3H]uridine and [3H]leucine into whole tissue, and 35SO4 into sulphated glycosaminoglycans (GAGs). Since GAGs are the components of cartilage matrix, the depletion of which is associated with osteoarthrosis, a method for measuring sulphated GAG synthesis in culture has been investigated.

Hip joint restoration in juvenile rheumatoid arthritis

Six children with long-standing juvenile rheumatoid arthritis and radiographic evidence of severe hip joint damage were found 6 months to 5 years afterward to have radiographic evidence of significant hip joint space widening and remodeling of articular surfaces. The disease activity had decreased and hip joint function had improved in all children. Each child had received various antiinflammatory drugs, but no specific medication could be implicated in the improvement. Evidence from animal studies suggests that intensive physical therapy with emphasis on continued weight bearing may have been important in promoting healing in these children. It appears that restoration of severely damaged hip joints in JRA can occur when the disease activity is controlled. Restoration may be favored by a child's greater potential for bone remodeling and by vigorous physical therapy with emphasis upon continued ambulation.