Objective. To evaluate the effects of fluoxetine and amitriptyline on nitric oxide (NO), prostaglandin E 2 (PGE 2), and hyaluronic acid (HA) production in human synovial cells and synovial tissue cultures. Methods. Human synovial cells, synovial tissue, and cartilage were cultured in the presence or absence of cytokines, lipopolysaccharides (LPS), fluoxetine, or amitriptyline. Production of NO, PGE 2 , and HA was determined in culture media. Sulfated glycosaminogly-can (S-GAG) synthesis was evaluated in cartilage by 35 S incorporation. Results. Fluoxetine (0.3 g/ml, 1 g/ml, and 3 g/ml) inhibited NO release by 56%, 62%, and 71%, respectively, in the media of synovial cells stimulated by interleukin-1 (IL-1; 1 ng/ml) plus tumor necrosis factor (TNF; 30 ng/ml). Amitriptyline (0.3 g/ml, 1 g/ml, and 3 g/ml) caused a 16%, 27.3%, and 51.4% inhibition of NO release. Fluoxetine and amitriptyline (0.3 g/ml, 1 g/ml, and 3 g/ml) significantly (P < 0.05) inhibited PGE 2 release in the media of human synovial cells in the presence of IL-1 plus TNF, in a dose-dependent manner (up to 88% inhibition). Fluox-etine (0.3 g/ml, 1 g/ml, and 3 g/ml) and amitripty-line (1 g/ml and 3 g/ml) significantly (P < 0.05) inhibited PGE 2 release in the media of human synovial tissue in the presence of LPS. Fluoxetine and amitrip-tyline (0.3 g/ml, 1 g/ml, and 3 g/ml) also significantly (P < 0.05) inhibited HA production by human synovial cells in the presence of IL-1 plus TNF. Fluoxetine and amitriptyline (1 g/ml) partially reversed IL-1-induced inhibition of 35 S-GAG synthesis by human cartilage cultures (P < 0.05). Neither fluox-etine nor amitriptyline had a toxic effect on cells in the concentrations used. Conclusion. Inhibition of NO and PGE 2 production by connective tissue cells is a mechanism by which some antidepressant medications may affect pain, artic-ular inflammation, and joint damage.

Objective-To evaluate the eVect of aminoguanidine (AG) on de novo interleukin 1 (IL1 ), nitric oxide (NO), and interleukin 1 receptor antagonist (IL1ra) production by osteoarthritic human synovial tissue and articular cartilage cultures. Methods-Synovial tissue and cartilage, obtained during surgery from 29 patients undergoing total knee or hip replacement for osteoarthritis, were cut into small pieces and cultured in the presence or absence of lipopolysaccharide (LPS) and test materials. IL1 , IL1ra, and NO were determined in culture media. The inducible nitric oxide synthase inhibitor, AG, was added to cultures in various concentrations (0.3-3 mmol/l). Results-In synovial tissue cultures AG (0.3, 1, and 3 mmol/l) decreased LPS (1 µg/ml) stimulated IL1 and NO release in the media in a dose dependent manner (p<0.05 at 1 mmol/l and p<0.05 at 0.3 mmol/l, respectively). In articular cartilage cultures AG (0.3, 1, and 3 mmol/l) decreased LPS (1 µg/ml) stimulated IL1 and NO release in the media in a dose dependent manner (p<0.05 at 1 mmol/l and p<0.01 at 0.3 mmol/l, respectively). Hydrocortisone (5 µg/ml) also significantly decreased LPS stimulated IL1 release in media of synovial tissue and cartilage cultures and NO in media of synovial cultures. AG (0.3, 1, and 3 mmol/l) decreased LPS (1 µg/ml) stimulated IL1ra levels in media of synovial tissue cultures in a dose dependent manner (p<0.05 at 1 mmol/l) but increased LPS (1 µg/ml) stimulated IL1ra release in media of cartilage cultures (p<0.01 at 3 mmol/l). The NO donor, nitroprusside (10, 30, 100, and 300 µg/ml) stimulated IL1 release in media of synovial tissue cultures in a dose dependent manner (p<0.01 at 100 µg/ml). AG and nitroprusside at the concentrations used had no toxic eVect on human synovial cells. Conclusions-NO synthase inhibitors may modulate osteoarthritis and articular inflammatory processes not only by decreasing NO synthesis but also by their eVects on IL and IL1ra production. (Ann Rheum Dis 2001;60:391-394) Cytokines have important roles in cartilage destruction in osteoarthritis (OA).1 2 Among them, it appears that interleukin 1 (IL1) has a key role 3 and nitric oxide (NO) also plays a part.4 Both IL1 and NO contribute to cartilage degradation and inhibition of its synthesis. Because IL1 was shown to stimulate NO production in osteoarthritic synovium and cartilage, 7 8 it has been suggested that the deleterious eVects of IL1 on articular cartilage are mediated, at least in part, by NO.9 10 Therefore, inhibitors of NO synthesis are being investigated as possible anti-arthritic agents.11 Aminoguanidine (AG) is a relatively selective inducible nitric oxide synthase inhibitor.

system in vitro was correlated with origin of synoviocytes. Moreover the relation between invasive growth of FLS in the transwell system and growth characteristics and expression of MMP 1-14, 17, 19, cathepsin K, TIMP-1 and -2 was determined. Methods FLS were derived from 56 patients (30 rheumatoid arthritis (RA), 17 osteoarthritis (OA), 9 avascular necrosis (AVN) or fractures). Invasive growth of FLS through a collagen matrix was measured in a transwell system coated with matrigel. The number of cells grown through the matrix and the transwell membrane were counted. Growth rate was determined by counting of FLS after seven days of culturing. Expression of MMP's, cathepsin-K and TIMP's was investigated using RT-PCR and related to expression of a household gene, beta-actin. Results FLS from RA invaded more easily in vitro than FLS from OA and AVN (median: RA: 4788 (cells grown through matrix and transwell membrane), OA: 1875; p <0.001 and AVN: 1530; p = 0.014 respectively). The median rate of proliferation of RA FLS was 0.27 per day compared to OA 0.22 per day (p = 0.012) and AVN and fractures 0.25 per day (RA versus AVN: p = 0.242; OA versus AVN: p = 0.553), but there was no correlation between rate of proliferation and invasive growth in vitro. FLS that expressed MMP-1, MMP-3 or MMP-10 were significantly more invasive (median number of invasive cells: 3835, 4248, 4990, respectively) than cells that did not express MMP-1, MMP-3 or MMP-10 (1605, p = 0.03; 1970, p = 0.004; 2360, p = 0.012, respectively). Expression of the other MMP's, cathepsin-K and TIMP's did not show a significant relationship with invasive growth. Expression of MMP-9 showed a trend with higher expression in more invasive cells (p = 0.066). There was also a significant relationship between the expression of MMP-1 and MMP-9 and a diagnosis of RA (both p = 0.013). Conclusion FLS of RA invade more easily in a matrigel matrix than OA FLS. This is not due to a greater rate of proliferation of RA FLS than OA FLS, although FLS from RA patients have a 25% higher rate of proliferation than FLS from OA patients. A significant relationship exists between the expression of MMP-1, MMP-3 and MMP-10 and invisive growth in a matrigel transwell system and this relationship was nearly significant for MMP-9. FLS of RA patients expressed significantly more often MMP-1 and MMP-9 than FLS from OA patients.