Facing the future: drug discovery reconsidered.
Explore the source record for details and available documents.
Anti-Inflammatory Agents, Non-Steroidal↗
Biomedical subjects
I G Otterness
Publications and source records attributed to I G Otterness.
Tenidap, a structurally novel drug for the treatment of arthritis: antiinflammatory and analgesic properties.
Tenidap is a new anti-rheumatic agent which has clinical properties characteristic of a disease modifying drug combined with acute antiinflammatory and analgesic activity. This paper details tenidap's cyclooxygenase (COX) inhibitory activity and the resulting pharmacological properties in experimental animals. Tenidap inhibited calcium ionophore-stimulated prostaglandin D2 synthesis by rat basophilic leukemia cells (COX-1) with an IC50 of 20 nM. In two different in vitro human test systems, tenidap inhibited COX-1 activity more potently than COX-2, although the relative potency ratio (COX-1/COX-2) differed markedly between the two systems. Tenidap inhibited the COX pathway when added to human blood in vitro (IC50, 7.8 mu M) and when administered orally to monkeys, rats and dogs (at 5, 2.5 and 10 mg/kg p.o., respectively) and COX activity measured ex vivo in blood collected 2 to 4 hours post dose. After oral administration to rats, tenidap inhibited carrageenan-induced paw edema with an ED50 of 14 mg/kg and inhibited the glucocorticoid-resistant UV erythema in guinea pigs with an ED50 of 1.4 mg/kg. It retained antiinflammatory activity in adrenalectomized rats indicating that this property is independent of adrenal stimulation. Oral administration of tenidap inhibited the development of adjuvant-induced polyarthritis in the rat and exhibited antinociceptive activity in the murine phenylbenzoquinone and rat acetic acid abdominal constriction tests. These data indicate that tenidap is an effective antiinflammatory and analgesic agent in animal models. These cyclooxygenase-dependent pharmacologic activities do not explain tenidap's disease modifying anti-arthritic properties but add a useful symptom modifying component to its clinical profile.
Analgesics, Non-Narcotic↗
Neutralization of endogenous IL-6 suppresses induction of IL-1 receptor antagonist.
IL-1 is a potent cytokine that promotes host defense and inflammation. These processes may be modulated by an IL-1 receptor antagonist (IL-1Ra) that binds to and blocks IL-1 receptors. The objective of this study was to define the cellular origin and regulation of IL-1Ra production during bacterial infection. Oral infection of mice with Yersinia enterocolitica resulted in expression of IL-1Ra mRNA and synthesis of IL-1Ra in Peyer's patches (PP), the local site of infection, as well as in noninfected organs such as spleens. By immunostaining, recruited circulating neutrophils were identified to be the primary source of IL-1Ra in tissues. Only approximately 20% of the IL-1Ra-staining cells were accounted for by inflammatory macrophages. Strikingly, neutralization of IL-6 by anti-IL-6 antiserum caused a suppression of both IL-1Ra mRNA in PP and synthesis of IL-1Ra in circulating neutrophils. Confirmatory evidence that IL-6 participates in the generation of IL-1Ra was obtained when rIL-6 induced, and anti-IL-6 antiserum blocked, IL-1Ra expression in cultures of macrophage and polymorphonuclear leukocytes (PMN). These findings suggest that IL-6 induced induction of IL-1Ra may provide a negative feedback loop, facilitating resolution of the inflammatory response locally and presumably at remote sites of infection.
Animals↗
ATP induces the release of IL-1 from LPS-primed cells in vivo.
The secretion of IL-1 from murine macrophages in vitro is an inefficient process that is distinct from those of other cytokines such as IL-6. We have therefore studied this process in vivo to see if these differences are maintained. Intraperitoneal injection of LPS in mice induced production and release of IL-6 into the extracellular fluid (peritoneal lavage). Although induction of intracellular IL-1 alpha and IL-1 beta was readily detected, these cytokines were not detected extracellularly. Injection of ATP 2 h after LPS led to the rapid extracellular release of IL-1 beta, IL-1 alpha, lactate dehydrogenase, and beta-N-acetylglucosaminidase. Western blot analysis revealed that a large proportion of the IL-1 beta was released as the 17-kDa form, whereas IL-1 alpha was unprocessed. Adenosine 5'-O-(3-thiotriphosphate) was also effective in causing IL-1 release but not UTP or ADP. This suggests that the ATP-mediated release of IL-1 is a receptor-mediated phenomenon that is associated with cell lysis.
Acetylglucosaminidase↗
Effects of tenidap on canine experimental osteoarthritis. I. Morphologic and metalloprotease analysis.
OBJECTIVE: To examine the effects of tenidap and diclofenac on osteoarthritic lesions and metalloprotease activity in experimental osteoarthritis (OA). METHODS: The anterior cruciate ligament of the right stifle joint of 25 mongrel dogs was sectioned by a stab wound. Seven dogs received no treatment, 6 were treated with oral omeprazole (20 mg/day), another 6 were treated with diclofenac (0.25 mg/kg/twice daily) plus omeprazole (20 mg/day), and 6 received oral tenidap (3 mg/kg/twice daily) plus omeprazole (20 mg/day). The dogs received medication for 8 weeks; all dogs were killed at the end of this period. Eight normal dogs were used as controls. Lesions were evaluated macroscopically for the incidence and size of osteophytes and the area and grade of cartilage erosions on the condyles and plateaus, along with histologic evaluation of the severity of the cartilage lesions and synovial inflammation. Stromelysin and collagenase activities and the collagenase messenger RNA (mRNA) level were measured in cartilage and synovial membrane. RESULTS: Compared with the untreated or omeprazole-treated OA groups, the dogs treated with tenidap exhibited significant reduction in the incidence (P < or = 0.001) and size (P < or = 0.0001) of osteophytes. Tenidap also significantly decreased the size and grade of cartilage macroscopic lesions, as well as the histologic severity of cartilage lesions on both condyles and plateaus. The histologic severity of synovial inflammatory reaction was also significantly reduced (P < or = 0.003) in the tenidap group. Tenidap markedly decreased stromelysin and collagenase activity in both cartilage (stromelysin P < or = 0.003; collagenase P < or = 0.01) and synovial membrane (stromelysin P < or = 0.003; collagenase P < or = 0.005). Moreover, tenidap also decreased the collagenase mRNA level in cartilage (P < or = 0.005) and synovial membrane (P < or = 0.002). Diclofenac slightly reduced the incidence and size of osteophytes and cartilage lesions, but these changes were not statistically significant. Diclofenac had no effect on the severity of synovial inflammation, metalloprotease activity, or collagenase expression. CONCLUSION: This study showed that tenidap had a more potent anti-osteoarthritic effect than diclofenac in this model. The effect of the drug in suppressing metalloprotease synthesis, a process known to play a major role in the pathophysiology of osteoarthritic lesions, may explain its mechanism of action.
Administration, Oral↗
Effects of exercise on synovium and cartilage from normal and inflamed knees.
The effect of running activity on normal and inflamed knees was determined by light microscopic (LM) and scanning electron microscopic (SEM) observations on hamster articular cartilage. Animals were split into two groups; one housed in standard cages and one given free access to running wheels. Twenty-one days prior to analysis, half of each group was given an intra-articular injection of lipopolysaccharide (LPS) to cause an inflammation, the other half were uninjected. No remarkable changes were observed by LM in either the control running or nonrunning groups. In contrast, cartilage proteoglycan depletion, and pannus and synovial hyperplasia were equally observed in both groups of LPS-injected animals. SEM observations on the patellae from control animals found them to be free from damage to the articular cartilage. The joints of both the LPS nonrunning and running animals contained synovial hypertrophy with villus projection from the synovial lining. However, only the LPS-injected running hamsters had cartilage fraying over large areas of the articular surface, as well as areas in which the villus projections had been flattened. These results demonstrated that mechanical stress applied to a proteoglycan-depleted cartilage enhances the breakdown of the collagen matrix as judged by fibrillation, and may aggravate the inflammation by crushing the swollen synovial lining where it encroaches on the joint space.
Animals↗
A study of the mechanism of action of the mild analgesic dipyrone.
The mechanism of action for the mild analgesics is controversial. While some have proposed that they inhibit prostaglandin synthesis in the central nervous system to interfere with nociceptive mediators in the brain, others have proposed that they act directly on nociceptive neural pathways to produce analgesia. This class of drugs also possesses antipyretic activity. We examined the antipyretic effect of one such drug, dipyrone, because this might elucidate the mechanism of its analgesic activity. In rats implanted with a femoral vein catheter and a cannula guide tube aimed towards the organum vasculosum laminae terminalis (OVLT) in the brain, an i.v. injection of 2 micrograms/kg interleukin-1 beta (IL-1 beta) produced a fever of 0.38 +/- 0.07 degrees C while an injection of 20 ng prostaglandin E1 (PGE) into the OVLT produced a fever of 1.18 +/- 0.18 degrees C. Dipyrone (25 mg/kg, i.v.) decreased the IL-1 beta fever but had no effect on the PGE fever. After pretreatment with the immunoadjuvant, zymosan, the IL-1 beta fevers were enhanced to equal those induced by PGE. Only 0.1 micrograms/kg, i.v. IL-1 beta raised body temperature by 1.20 +/- 0.10 degrees C. An increased dose of dipyrone (50 mg/kg, i.v.) was required to attenuate this IL-1 beta fever; however, the PGE fever remained unaffected by this treatment with dipyrone. Thus, dipyrone treatment blocks IL-1 beta fever where synthesis of prostaglandin is a crucial step in the febrile process, but it has no effect on PGE fever where synthesis is bypassed. This suggests that dipyrone, probably through its active metabolites, inhibits prostaglandin synthesis to induce antipyresis and, by analogy, analgesia as well.
Animals↗
Proteoglycan loss and subsequent replenishment in articular cartilage after a mild arthritic insult by IL-1 in mice: impaired proteoglycan turnover in the recovery phase.
The reparative responses of articular cartilage after an arthritic insult have not been studied extensively to this day. In the present study, we injected interleukin-1 (IL-1) into knee joints of mice to provoke a mild and transient arthritic insult, and characterized both the catabolic and the subsequent recovery phase. In the catabolic phase, which lasted 2 days after IL-1 injection, proteoglycan (PG) breakdown was profoundly accelerated and PG synthesis was markedly inhibited. Sulfation and polysaccharide synthesis were not affected, yet the number of chondroitin sulfate chains was decreased. The general chondrocyte protein synthesis was not inhibited by IL-1. IL-1 injected every other day for a total of three injections prolonged this catabolic phase and resulted in frank loss of articular cartilage proteoglycans. In the recovery phase, started 3 days after IL-1, PG synthesis was enhanced (1.7 times the normal) and proteoglycans had normal hydrodynamic properties. Remarkably, PG degradation was significantly decreased (approximately 50% of the normal). Zymographic analysis demonstrated enhanced expression of gelatinolytic activities in the extracts of the articular tissues shortly after IL-1 exposure and decreased levels in the recovery phase. We found that the overshoot of PG synthesis and impaired degradation act together to facilitate full cartilage repair 7 days after the last of the three IL-1 injections.
Animals↗
Transcriptional and translational regulation of IL-1 alpha and IL-1 beta account for the control of IL-1 in experimental yersiniosis.
Interleukin 1 (IL-1) gene expression was investigated in mice following oral infection with Yersinia enterocolitica 08. In Peyer's patches (PP), the primary site of bacterial invasion, induction of IL-1 alpha mRNA was delayed when compared to IL-1 beta mRNA. As shown by in situ hybridization. IL-1 alpha and IL-1 beta mRNA were found to be expressed within different cell types. These results indicate that expression of the two forms of IL-1 is regulated in a cell-specific manner at the transcriptional level. Moreover, IL-1 (alpha and beta) mRNA was increased in other organs such as spleen and lung. In spleens, IL-1 beta mRNA was found within the red pulp, and IL-1 alpha mRNA was located to the marginal zone confirming that differential expression of IL-1 alpha and IL-1 beta mRNA does not represent a tissue-specific event. However, as revealed by immunohistochemistry and measuring IL-1 activity in tissue homogenates, synthesis of IL-1 proteins was not detectable in spleens, unless mice were challenged with LPS. Because IL-1 synthesis was inducible in spleen cells following actinomycin D treatment, the results indicate that at distant sites of infection IL-1 (alpha and beta) mRNA is expressed but not translated into protein. It is concluded that cell-specific transcription of IL-1 alpha and IL-1 beta as well as dissociation between IL-1 mRNA and protein synthesis are two mechanisms effective in regulating the production of IL-1 during infection.
Animals↗
The value of C-reactive protein measurement in rheumatoid arthritis.
Since 1973, assessment of serum concentrations of C-reactive protein (CRP) has been advocated as a objective measure of disease activity in rheumatoid arthritis (RA). Our review of clinical experience with CRP measurement suggests it has at least two important roles to play in the management of RA. First, persistently elevated CRP levels have prognostic value. In general, such elevated levels are found in those patients who are at greater risk for continuing joint deterioration and therefore may need more aggressive treatment and supportive care. Second, in general, improvement in CRP levels is an objective indication that a drug has produced a beneficial effect and thus may be useful to the physician for monitoring effects of therapy. Since CRP may be elevated in a number of conditions besides RA, a diagnosis of RA must be made before using CRP as a prognostic factor.
Anti-Inflammatory Agents, Non-Steroidal↗
Comparison of mobility changes with histological and biochemical changes during lipopolysaccharide-induced arthritis in the hamster.
Arthritis refers to a heterogeneous class of diseases characterized by impairment of movement. Yet animal models of arthritis have traditionally been based on the utilization of animals housed without the capability of extended free movement and without adjunctive measurement of mobility. To define the determinants of mobility impairment, we have established a lipopolysaccharide (LPS)-induced arthritis model in the hamster that prominently features monitoring of mobility and compares mobility changes with histological and biochemical changes during arthritis. Intraarticular LPS induces a dose-dependent inhibition of the hamster's mobility as measured by decreased daily distance on a running wheel (normal distance 9 to 12 km/day). At low concentrations of LPS (0.1 and 1 microgram/knee), daily distances returned to normal after 4 and 6 days, respectively. At higher concentrations, the mobility was still markedly suppressed after 6 days, and, at 100 micrograms/knee, irreversible chondrocyte loss was observed on the femoral condylar margins. Further studies were therefore conducted using 1 microgram LPS/knee. Histological and biochemical changes were examined to determine which resolved at the time of restoration of mobility. At the time of restoration of mobility, the synovial capsule was still edematous and heavily infiltrated with leukocytes; proteoglycan loss from the medial femoral condyle was still increasing. Plasma keratan sulfate failed to correlate with either proteoglycan loss or mobility changes. Proteoglycan synthesis, which was maximally suppressed the second day after LPS, was enhanced over controls at the time of restoration of mobility, suggesting the onset of repair. These results suggest a possible association of mobility inhibition with local cytokine synthesis. This model provides an approach to define the causes of mobility impairment.
Animals↗
Possible role of IL-1 in arthritis: effects of prostaglandins in the regulation of IL-1 synthesis and actions.
Explore the source record for details and available documents.
Animals↗
Modulation of cartilage destruction in murine arthritis with anti-IL-1 antibodies.
One of the early events in murine antigen-induced arthritis is the generation of IL-1 in the inflamed joint. We investigated the role of IL-1 in the acute phase of the arthritic process by selective blockage of IL-1 bioactivity by treatment with neutralizing antibodies. Pretreatment with anti-IL-1 antibodies moderately suppressed joint swelling. The decrease in chondrocyte proteoglycan synthesis seen in the acute phase of arthritis was prevented by treatment with anti-IL-1 antibodies. IL-1 does not appear to be a major contributor to the accelerated breakdown of articular cartilage in this model. The major impact of anti-IL-1 antibodies was the prevention of proteoglycan synthesis inhibition which clearly reduced articular cartilage depletion by maintaining normal proteoglycan synthesis.
Animals↗
Some factors affecting inhibition and restoration of mobility after induction of an acute arthritis in the hamster.
Mobility is impaired during arthritis. In order to study the causes of the mobility impairment, we have examined hamsters with a LPS arthritis in which running is inhibited over a 4-5 day period. Parameters have been examined to determine which correlate with running impairment. Knee diameter, as well as cell infiltration into the surrounding synovial tissue and the accompanying edema, failed to resolve by the time normal mobility was reestablished. Other factors must be primary determinants of mobility.
Animals↗
Transition from interleukin 1 beta (IL-1 beta) to IL-1 alpha production during maturation of inflammatory macrophages in vivo.
In situ production of interleukin 1 alpha (IL-1 alpha) and IL-1 beta was investigated in Peyer's patches (PP) of mice undergoing an acute bacterial infection with Yersinia enterocolitica O8. Synthesis of IL-1 beta, as determined by immunohistochemistry, was found primarily in monocytes migrating into the inflamed PP. In comparison, synthesis of IL-1 alpha was temporarily delayed by at least 24 h and was only found in mature macrophages, which did not produce detectable levels of IL-1 beta. This indicates a transition from IL-1 beta to IL-1 alpha production during maturation of monocytes into inflammatory macrophages, and further emphasizes a dichotomy between IL-1 alpha and IL-1 beta.
Animals↗
Biologic and immunohistochemical analysis of interleukin-6 expression in vivo. Constitutive and induced expression in murine polymorphonuclear and mononuclear phagocytes.
Interleukin-6 (IL-6) is considered an important multifunctional cytokine involved in the regulation of a variety of cellular responses, including the induction of acute-phase protein synthesis, lymphocyte activation, and hematopoiesis. In vitro studies have identified many cells that can produce IL-6, but the cellular sources under physiologic conditions have yet to be identified. Using immunoaffinity purified goat anti-murine IL-6, the authors performed immunohistochemical studies to localize cells expressing IL-6 in selected organs of normal and endotoxin challenged NIH-Swiss outbred mice. In the blood, findings were correlated with cell-associated bioactivity using the standard B9 cell proliferation assay. In normal mice, constitutive expression was seen in granulocytes, monocytes and their precursors as well as in bone marrow and splenic stromal macrophages. Hepatic macrophages were negative, as were lymphocytes, megakaryocytes, erythroid precursors, and endothelial cells. In the absence of significant serum levels of IL-6, cell-associated IL-6 bioactivity was detected in circulating polymorphonuclear leukocytes (PMNs), but not lymphocytes. After endotoxin challenge, there was a threefold increase in PMN IL-6 content from 1 to 3 hours followed by almost complete depletion at 6 hours. This correlated well with a threefold increase of IL-6 mRNA in the bone marrow followed by a decrease at 6 hours. This pattern also correlated with serum levels of IL-6, which peaked at 3 hours and dropped significantly by 6 hours. By 24 hours, cell-associated IL-6 showed recovery with no increase in serum levels. In vivo findings showing IL-6 expression in bone marrow macrophages support in vitro studies suggesting a role for IL-6 in hematopoiesis. Furthermore, PMNs as well as macrophages are likely important sources of IL-6 during inflammatory and septic states.
Animals↗
Protection against cartilage proteoglycan synthesis inhibition by antiinterleukin 1 antibodies in experimental arthritis.
We have used neutralizing antibodies raised against murine recombinant interleukin 1 (IL-1) to demonstrate a role for IL-1 in the cartilage destruction and inflammation of antigen induced arthritis. Ex vivo production of IL-1 was demonstrated in tissue cultures of joint cross sections shortly after arthritis induction. Neutralizing antimurine IL-1 antibodies identified the activity to be about 80% IL-1 alpha 24 h after onset of arthritis. In animals receiving a single injection of anti-IL-1 antisera at Day -3, cartilage proteoglycan synthesis suppression during the first 2 days of arthritis was prevented. Normal proteoglycan synthesis was maintained until Day 4 when anti-IL-1 antisera was given at Days -2, 0, and 2 or arthritis. Dose response experiments showed that the reduction in inflammation was insufficient to account for the clearcut reduction in cartilage proteoglycan synthesis inhibition. Our results demonstrate that IL-1 plays a role in cartilage pathology in murine antigen induced arthritis.
Animals↗
Isolation and characterization of biologically active murine interleukin-6 produced in Escherichia coli.
Interleukin-6 (IL-6) is a multi-functional cytokine produced and secreted by several different cell types, including those of the immune system. A cDNA coding for the mature murine IL-6 (mIL-6), which extends from amino acid (aa) 25 through 211, was cloned into a prokaryotic vector and then expressed in Escherichia coli. The recombinant mIL-6 (remIL-6) was isolated from bacterial inclusion bodies by solubilization in 4 M guanidine hydrochloride followed by gel-filtration chromatography. The protein was refolded to an active conformation by dialysis against 25 mM Na. acetate pH 5.5. A final step of purification and concentration on a cation exchange resin yielded pure and biologically active remIL-6. The purified preparation had the expected aa composition, as confirmed by aa analysis and pI of 7.0-7.1. The biological activity of the recombinant protein was measured in two systems; a proliferation assay employing 7TD1 cells, and a fibrinogen biosynthesis assay employing primary rat hepatocytes. Both assay systems demonstrated that the remIL-6 was active in the range of 10(8) units/mg, which is similar to that estimated for native cytokine. Antibodies raised in rabbits against remIL-6 neutralized the biological activity of both recombinant and native IL-6.
Animals↗