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D Jovanovic

Publications and source records attributed to D Jovanovic.

At least 19 recordsLinked to original sources
PubMed2001

Effects of atropine, trimedoxime and methylprednisolone on the development of organophosphate-induced delayed polyneuropathy in the hen.

In this study we have examined the effects of atropine, trimedoxime (TMB-4) and methylprednisolone (MP) on the development of organophosphate-induced delayed polyneuropathy (OPIDP) in the hen. The birds were treated with standard neuropathic dose of diisopropylfluorophosphate (DFP) (1.1 mg/kg, sc), which produced OPIDP that could be graded as 5 on the 8-point scale, and the development of OPIDP was observed for the next 22 days. The results obtained have shown that atropine (20 mg/kg, ip), TMB-4 (15 mg/kg, im) and MP (2 or 10 mg/kg, ip) either alone or in different combinations are able to improve the condition of the birds. The most potent effect was obtained with atropine, TMB-4 (given 20 min before DFP) and MP (2 mg/kg, sc, given 20 min before and at 48 hour intrevals after poisoning) since the signs of OPIDP could hardly be seen (grade 1 at the 8-point scale). When TMB-4 and MP were given 15 or 40 min after DFP the protective/therapeutic effects of these drugs appeared to be diminished since walking disorders were more serious and graded as 2 or 4, respectively. The possible mechanisms of the action of the drugs in respect to OPIDP are discussed. In conclusion, the results of this study have shown that it is possible to prevent the development of DFP-induced OPIDP in the hen by treatment with atropine, trimedoxime and methylprednisolone when they were given before or soon after DFP.

Animals↗
PubMed2000

Nonlinear model for coherent electric field structures in the magnetosphere

A new pseudo-three-dimensional electron hole in a magnetized plasma is possible when the low-frequency ion dynamics is taken into account. The newly found nonlinear Bernstein-Greene-Kruskal stationary solution, whose parallel phase velocity ranges between almost zero and the electron thermal speed, has the form of a cylinder that is tilted relative to the magnetic field. These structures are interpreted as three-dimensional electron holes coupled with hydrodynamic vortices, and provide a possible theoretical explanation for the POLAR and FAST satellite observations of coherent structures characterized by bipolar spikes of the parallel electric field and large perpendicular ion kinetic energies.

Journal Article↗
PubMed2000

Kinetic vortex chain solution in the drift-wave plasma regime

A fully nonlinear Bernstein-Greene-Kruskal stationary solution is found in the form of a quasi-three-dimensional chain of electron holes coupled to hydrodynamic vortices. This new coherent structure is enabled by the trapping and depletion of resonant particles, and the cyclotron dissipation of the singular current sheets. It is expected to play an important role in the collisionless magnetic field line reconnection in the drift-wave plasma regime, where it represents a plausible saturated state.

Journal Article↗
PubMed2000

Vortices in relativistic electron beams

We demonstrate that a relativistic electron beam is properly described in the moving frame by the electron-magnetohydrodynamic equations of plasma physics. For large beam currents, the accelerator magnetic field is expected to be unstable to the fast magnetic reconnection. We present a plausible saturated state of the fast reconnection, in the form of a complex vortex pattern. The nonlinear dispersion equations of the vortex are derived and the relationship between the vortex structure and the background magnetic field is discussed.

Journal Article↗
PubMed1999

Mitogen-activated protein kinase and nuclear factor kappaB together regulate interleukin-17-induced nitric oxide production in human osteoarthritic chondrocytes: possible role of transactivating factor mitogen-activated protein kinase-activated proten kinase (MAPKAPK).

OBJECTIVE: To explore the signaling pathways by which the proinflammatory cytokine interleukin-17 (IL-17) may contribute to cartilage catabolism in osteoarthritis (OA) by inducing inducible nitric oxide synthase (iNOS) expression in chondrocytes. METHODS: We examined the IL-17-induced NO production in human OA chondrocytes, in combination with the proinflammatory cytokines IL-1beta, tumor necrosis factor alpha (TNF alpha), and leukemia inhibitory factor (LIF); the antiinflammatory cytokines IL-4, IL-10, and IL-13; and IL-1 receptor antagonist (IL-1Ra). Further, we explored the major intracellular signaling pathways through which IL-17 induced iNOS expression and NO production. RESULTS: Treatment with IL-17 induced a dose-dependent increase in the level of NO. When IL-17 was combined with the above factors, it resulted in a synergistic effect with TNF alpha, an additive effect with LIF, and no further effect than when used alone with IL-1beta. IL-4, IL-10, IL-13, and IL-1Ra had no true effect on IL-17-induced NO production. The cAMP mimetics, 3-isobutyl-1-methyl xanthine plus forskolin, completely blocked IL-17-induced NO production. KT-5720, genistein, and Calphostin C, inhibitors of protein kinase A (PKA), tyrosine kinase, and protein kinase C, respectively, reduced the IL-17-induced NO production by 72%, 56%, and 42%, respectively. Within minutes, IL-17 induced the phosphorylation of mitogen-activated protein kinase kinase-1/2 (MEK-1/2), -3/6 (MKK-3/6), p44/42, p38, and inhibitor of nuclear factor kappaB (I kappaB)-alpha, as well as the activation of mitogen-activated protein kinase-activated protein kinase-1 and -2 (MAPKAPK-1 and -2). Interestingly, IL-17 induced phosphorylation of the stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK) (p54/46) only when PKA was inhibited. Specific protein kinase inhibitors for MEK-1/2 (PD98059), p38 (SB202190), and nuclear factor kappaB (NF-kappaB) (pyrrolidine dithiocarbamate) each markedly decreased the IL-17-increased iNOS level and NO production. Inhibiting MAPK, including MEK-1/2 and p38, had no effect on the IL-17-induced activation of IkappaB-alpha, but reversed the IL-17 activation of MAPKAPK-1 and -2, respectively. CONCLUSION: These findings show that the stimulation of NO production by IL-17 is mediated mainly by a complex activation of kinases, especially PKA, NF-kappaB, and MAPK. NF-kappaB appears to require MAPK activation, with downstream activation of MAPKAPK probably acting as a transactivating factor, to induce iNOS expression.

Aged↗
PubMed1999

Reduction in the structural changes of experimental osteoarthritis by a nitric oxide inhibitor.

OBJECTIVE: To evaluate the in-vivo therapeutic efficacy of N -iminoethyl-L-Lysine (L-NIL), a selective inhibitor of inducible nitric oxide synthase (iNOS) in a dose response study, on the progression of lesions in the experimental osteoarthritic (OA) dog model. DESIGN: The sectioning of the anterior cruciate ligament of the right stifle joint of mongrel dogs was done by a stab wound. Dogs were separated into experimental groups: Group 1 received no treatment, Groups 2, 3, and 4 received oral L-NIL (0.3, 1 or 10mg/kg/day, respectively) starting immediately after surgery. The OA dogs were killed at 12 weeks after surgery. RESULTS: Macroscopically, L-NIL decreased the size of the cartilage lesions on condyles and plateaus. The histologic severity of the cartilage lesions was decreased in the L-NIL-treated dogs. This effect was more pronounced at the highest dosage tested (3 and 10mg/kg/day). CONCLUSIONS: This study confirms the effectiveness of L-NIL, a selective inhibitor of iNOS, in attenuating the progression of experimental OA. It also clearly shows that the effect is dose-dependent.

Animals↗
PubMed1999

Selective inhibition of inducible nitric oxide synthase in experimental osteoarthritis is associated with reduction in tissue levels of catabolic factors.

OBJECTIVE: We used the experimental dog model of osteoarthritis (OA) to examine the in vivo effects of N-iminoethyl-L-lysine (L-NIL), a selective inhibitor of the inducible nitric oxide synthase (iNOS), on the tissue level and distribution of interleukin-1beta (IL-1beta), collagenase-1, stromelysin-1, cyclooxygenase-2 (COX-2), iNOS and nitrotyrosine, through immunohistochemical and morphometric analysis. METHODS: Cartilage and synovial membrane specimens were obtained from 3 experimental groups of dogs: Group I--unoperated dogs that received no treatment; Group II--dogs subjected to a sectioning of the anterior cruciate ligament of the right knee and given no treatment; and Group III--operated dogs that received oral treatment with L-NIL (10 mg/kg twice daily/po) for 10 weeks starting immediately after surgery. The operated dogs were killed 10 weeks post-surgery. The tissue distributions of IL-1beta, metalloproteases (MMP), COX-2, iNOS and nitrotyrosine were documented by immunohistochemistry using specific antibodies, and quantified by morphometric analysis. RESULTS: In cartilage, the cell scores (percentage of chondrocytes staining positive for the antigen) for iNOS and 3-nitrotyrosine were dramatically enhanced in OA specimens compared to normal (p < 0.0001). However, the cartilage of dogs treated with L-NIL showed significantly lower cell scores for iNOS (p<0.0001, condyle; p<0.001, plateau), nitrotyrosine (p<0.0004; p<0.0001) and COX-2 (p<0.0001; p<0.001) compared to that of untreated OA dogs. Similar findings were observed for collagenase-1 and stromelysin-1, where the increased cell scores of these 2 MMP in OA cartilage were reduced after treatment with L-NIL (collagenase: p<0.002, condyle; p<0.0003, plateau; stromelysin: p<0.006; p<0.0001). The increased cell scores for the IL-1beta, COX-2, iNOS and nitrotyrosine found in the synovial lining and mononuclear cell infiltrate of operated animals were also found to be markedly reduced in dogs treated with L-NIL. CONCLUSION: Our study demonstrates for the first time in vivo in an experimental model of OA, that a selective inhibition of iNOS by L-NIL and the subsequent decreased production of NO also results in a marked decrease in production of major catabolic factors such as MMP, IL-1beta and peroxynitrite, as well as a reduction in COX-2 expression.

Animals↗
PubMed1998

Reduced progression of experimental osteoarthritis in vivo by selective inhibition of inducible nitric oxide synthase.

OBJECTIVE: To evaluate the in vivo therapeutic efficacy of N-iminoethyl-L-lysine (L-NIL), a selective inhibitor of inducible nitric oxide synthase (iNOS), on the progression of lesions in an experimental osteoarthritis (OA) dog model. The effect of L-NIL on metalloprotease activity, levels of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), and nitrite/nitrate in synovial fluid was determined. METHODS: The OA model was created by sectioning the anterior cruciate ligament of the right stifle joint of mongrel dogs by a stab wound. Dogs were separated into experimental groups: Group 1 was made up of unoperated dogs that received no treatment, group 2 were operated dogs with no treatment, and group 3 were operated dogs that received oral L-NIL (10 mg/kg/twice daily) starting immediately after surgery. The OA dogs were killed at 10 weeks after surgery. RESULTS: Experiments showed that dog OA cartilage explants in culture produced an increased amount of NO (nitrite). Immunohistochemical study demonstrated that this was due to an increased level of iNOS in chondrocytes. OA dogs treated with L-NIL showed a reduction in the incidence of osteophytes compared with the untreated OA dogs (58% versus 92%) as well as in their size (mean +/- SEM 1.92 +/- 0.58 mm versus 5.08 +/- 0.66 mm). Macroscopically, L-NIL decreased the size of the cartilage lesions by approximately 50% both on condyles and plateaus. The histologic severity of both the cartilage lesions and synovial inflammation was significantly decreased in the L-NIL-treated dogs. Treatment with L-NIL also significantly decreased both collagenase and general metalloprotease activity in the cartilage and the levels of IL-1beta, PGE2, and nitrite/nitrate in synovial fluid. CONCLUSION: This study demonstrated the effectiveness of a selective inhibitor of iNOS, L-NIL, in attenuating the progression of experimental OA. The data suggest that L-NIL may act by reducing the activity of metalloproteases in cartilage and the production of IL-1beta by synovium, both of which are known to play a major role in the pathophysiology of OA structural changes.

Animals↗
PubMed1998

Effect of IL-13 on cytokines, cytokine receptors and inhibitors on human osteoarthritis synovium and synovial fibroblasts.

OBJECTIVE: In this study we investigated the effect of interleukin-13 (IL-13), an anti-inflammatory cytokine, for potential therapeutic use in osteoarthritis (OA). DESIGN: We examined the effect of IL-13 on the synthesis and expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), IL-1 receptor antagonist (IL-1Ra) and stromelysin-1 on human OA synovial membrane in ex vivo cultures. In addition, we explored the effect of IL-13 on both the IL-1 receptor (IL-1R) and TNF-receptor (TNF-R) systems on OA synovial fibroblasts. This included determination of the levels of IL-1 beta and TNF-alpha receptor binding, IL-1Ra and TNF-soluble receptors 55 and 75 (TNF-sR55 and TNF-sR75). RESULTS: In OA synovial membrane treated with LPS, IL-13 inhibited the synthesis of IL-1 beta, TNF-alpha and stromelysin-1, but increased IL-1Ra production. In addition, IL-13 reduced the level of IL-1 beta mRNA and stimulated the level of IL-1Ra mRNA. In synovial fibroblasts, IL-13 decreased the level of IL-1 binding, an effect related to the increased production of IL-1Ra. Although IL-13 had no effect on the TNF-R level, this cytokine markedly decreased the shedding of TNF-R75. CONCLUSION: These experiments suggest that IL-13 is potentially useful in the therapeutic treatment of OA, as it could regulate the major pathological process of this disease by reducing the production of proinflammatory cytokines and metalloproteases, and favoring the production of IL-1Ra.

Aged↗
PubMed1998

Effects of captopril on morphologic changes in kidney of spontaneously hypertensive rats with adriamycin nephropathy.

Antihypertensive therapy has been shown to slow down the progression of chronic renal failure. Angiotensin converting enzyme inhibitors and calcium antagonists have been emphasized as the agents with the most protective effect. Our previous study showed that captopril slowed down renal function deterioration in the early course of adriamycin (ADR) nephropathy in spontaneously hypertensive rats (SHR). The present study was undertaken with the aim to examine morphologic changes associated with that slower renal function deterioration. Adult (24 weeks) female SHR were randomly divided into the following groups: the control group (n = 12) was given tap water to drink; the adriamycin (ADR) group (n = 25) was treated with ADR; the ADR-captopril (ADR-C) group (n = 27) was treated with ADR and thereafter with captopril (60 mg/kg/day). Rats were sacrificed at weeks 6, 12 and 18 and histologic analysis was semiquantitatively performed. In the control group the glomeruli exhibited only minor changes at the end of the study. In the ADR group slight glomerular mesangial hypercellularity appeared in the sixth week and progressed in focal and segmental sclerosis. Some glomeruli showed segmental proliferation and increased fibrular matrix of a tuft adherent to a fibrocellular crescents. In the ADR-C group, glomeruli with a slight increase of mesangial matrix were seen at the end of the sixth week, mesangial hypercellularity developed until the end of the sixth week, mesangial hypercellularity developed until the end of the 12th week and segmental glomerulosclerosis until the end of the study. Semiquantitative analysis revealed that the mean semiquantitative scores for mesangial expansion and glomerular sclerosis were significantly lower in ADR-C group than in ADR group throughout the study. We concluded that captopril slowed down mesangial expansion and reduced the development of glomerular sclerosis.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

The effects of tenidap on canine experimental osteoarthritis: II. Study of the expression of collagenase-1 and interleukin 1beta by in situ hybridization.

OBJECTIVE: To examine the effect of tenidap on the expression of collagenase- and interleukin 1beta (IL-1beta) genes in experimental canine osteoarthritis (OA). METHODS: The anterior cruciate ligaments of the right stifle joints of experimental dogs were sectioned by a stab wound incision and tissues samples were taken. Four dogs had received no treatment, 4 were treated with oral omeprazole (20 mg/day), and another 4 were treated with tenidap (3 mg/kg/bid) and omeprazole (20 mg/day). The dogs received medication for 8 weeks; all dogs were sacrificed at the end of this period. Tissues from 4 healthy dogs were used as controls. IL-1beta and collagenase-1 gene expression were measured in synovial membrane (synovial lining cells and mononuclear cell infiltrate) and collagenase-1 expression in cartilage using in situ hybridization techniques. Results were calculated as the percentage of cells expressing the gene, and expressed as cell score. RESULTS: The collagenase-1 cell score in the full thickness samples was significantly higher in OA cartilage than in normal cartilage, both in condyles and plateaus (p < 0.0002). Tenidap treated dogs showed a significantly lower cell score in femoral condyles and tibial plateaus in the superficial (p < 0.0002), deep (p < 0.005, p < 0.002, respectively), and full thickness (p < 0.0002) layers compared to OA dogs. No staining for collagenase-1 was observed in normal membrane. In OA synovial membrane, the collagenase-1 cell score was high in both the synovial lining cells and mononuclear cell infiltrate. Tenidap treated dogs showed a significantly lower score compared to OA tissue in both the synovial lining cells (p < 0.03) and the mononuclear cell infiltrate (p < 0.03). The relative decrease in the collagenase-1 cell score in the tenidap treated dogs was more pronounced in the mononuclear cell infiltrate. Staining for IL-1beta was observed in only a few lining cells in normal synovial membrane from unoperated dogs. In OA synovial membrane from untreated dogs, staining for IL-1beta was intense and was found in all dog specimens. The cell score was significantly higher in OA lining cells (p < 0.03) and mononuclear cell infiltrate (p < 0.03) compared to normal. In tenidap treated dogs, the score for IL-1beta was significantly lower than in OA, both in synovial lining cells (p < 0.03) and mononuclear cell infiltrate (p < 0.03). CONCLUSION: Tenidap significantly reduced in vivo expression of collagenase-1 and IL-1beta in experimental OA. These data are an extension of our previous study and showed that tenidap exerts its protective effects on OA lesions, likely by reducing the catabolic pathways of the disease.

Animals↗
PubMed1998

Collagenase-1 and collagenase-3 synthesis in normal and early experimental osteoarthritic canine cartilage: an immunohistochemical study.

OBJECTIVE: The coexistence of different collagenases in cartilage suggests the possibility of specific roles for these enzymes in the degradation of the collagen network in osteoarthritis (OA). We investigated the in situ synthesis and distribution of collagenase- and collegenase-3 in normal and early experimental OA cartilage. METHODS: The OA model was created on 12 mongrel dogs by sectioning the anterior cruciate ligament of the right stifle joint with a stab wound. Dogs were divided into 3 groups of 4 animals each, and sacrificed at 4, 8, and 12 weeks, respectively. A 4th group (n = 4) of unoperated dogs was used as control. Articular cartilage from femoral condyles and tibial plateaus was examined histologically to grade severity of lesions, and immunohistochemical and morphometric analyses were performed to detect the presence of chondrocytes producing collagenase-1 and -3. RESULTS: In OA dogs, the histologic severity of lesions increased with time, being most severe at 8 and 12 weeks after surgery. In cartilage from OA compared to unoperated dogs, the immunoreactivity was 5-9 times higher (p < 0.0002) for collagenase-1, and 3-6 times higher (p < 0.0002) for collagenase-3, in both femoral condyles and tibial plateaus. Although the cell score increased throughout the cartilage, comparison of the superficial and upper intermediate layers (superficial) with the lower intermediate and deep layers (deep) revealed a significantly higher level for collagenase-1 (p < 0.007) in the superficial layers, contrary to the collagenase-3 data, which indicated a higher level (p < 0.007) in the deep layers. For collagenase- , the cell score increased steadily up to the 12th week, and for collagenase-3, the elevation peaked at 8 weeks. Correlation between the histologic severity and cell score in cartilage specimens from unoperated and OA dogs revealed the highest coefficient for collagenase- at the superficial layers (r = 0.69, p < 0.0001), while for collagenase-3, this was noted at the deep layers (r = 0.65, p < 0.0004). CONCLUSION: The number of chondrocytes involved in the synthesis of collagenase-1 and collegenase-3 increases dramatically in the early phase of OA. However, the difference in the topographic distribution of these enzymes, as well as the variation in their correlation pattern, may reflect a different function allocated for each collagenase in the OA cartilage degradation process.

Animals↗
PubMed1998

[Resection of the anterior cruciate ligament of the knee using arthroscopy induces arthrosis in dogs. Validity of the Pond-Nuki model].

INTRODUCTION AND GOAL: The dog model of osteoarthritis is the one most used for the study of the pathophysiology of this disease, given its resemblance to human osteoarthritis. Although the percutaneous section of the ligament is the most known technique, variability of and iatrogenic lesions might occur. The goal of this study was to validate the arthroscopic technique regarding the osteaorthritic lesions found in the percutaneous Pond-Nuki dog model. METHODS: The arthroscopic section of the canine anterior cruciate ligament (ACL) was compared to the percutaneous technique. Six dogs were operated percutaneously (Group I) and another six by arthroscopy (Group II). At eight weeks, animals were sacrificed and analysis were done on the osteophytes (mm) and cartilage lesions [macroscopy (Pelletier scale: grade 0-4, and size, mm2)] and [microscopy (Mankin scale: 0-14)] on femoral condyles and tibial plateaus. RESULTS: Osteophytes (Group I: 3.4 mm, Group II: 4.4 mm) and cartilage lesions (grade: 2.07 and 1.67; size: 27.9 and 33.9 m, respectively) on both femoral condyles and tibial plateaus are similar and not statistically different. Total microscopic scoring for both groups (6.2 and 6.5, respectively) are also similar and not statistically significant. DISCUSSION: Experimental osteoarthritis induced by arthroscopic transection of the ACL in dogs is characterised by macroscopic and microscopic lesions that resemble those found after percutaneous stab transection. Arthroscopic technique is more reliable and the present results allow its validation regarding the classical percutaneous technique.

Animals↗
PubMed1997

Effects of tenidap on the progression of osteoarthritic lesions in a canine experimental model. Suppression of metalloprotease and interleukin-1 activity.

OBJECTIVE: To study, in vivo, the therapeutic effectiveness of tenidap, an antirheumatic drug, on the progression of lesions in an experimental osteoarthritis (OA) dog model. The action of tenidap on the activity and expression of metalloproteases in cartilage, as well as on the bioactivity of interleukin-1 (IL-1) in synovial fluid, was determined. METHODS: The anterior cruciate ligament of the right stifle joint of 20 mongrel dogs was sectioned through a stab wound. Dogs were divided into 3 groups: group I (n = 7) received no treatment, group II (n = 6) was treated with oral omeprazole (20 mg/day), and group III (n = 7) received oral omeprazole (20 mg/day) and a therapeutic dosage of oral tenidap (3 mg/kg twice daily). Four weeks following surgery, the untreated dogs (group I) were killed, and drug treatments were begun for the other dogs (groups II and III). These dogs received medications for 8 weeks (weeks 4-12) and then were killed. Evaluations were made of the incidence and size of osteophytes as well as of the size and grade of cartilage erosions on both the condyles and plateaus. Histologic examination of the severity of the cartilage lesions and synovial inflammation was also performed. Activity levels of collagenase, stromelysin, and gelatinase as well as collagenase-1, collagenase-3, and stromelysin-1 messenger RNA were determined in the cartilage. The level of IL-1 activity in the synovial fluid was also measured. RESULTS: Among the dogs with OA, lesions were more severe at 12 weeks than at 4 weeks. Group III (tenidap-treated) dogs had a slightly reduced incidence of osteophytes compared with the group II (12-week OA) dogs (71% versus 100%), and the size of the osteophytes was significantly diminished (mean +/- SEM 1.75 +/- 0.69 mm versus 4.38 +/- 0.64 mm). Macroscopically, tenidap decreased the size (condyles 6.00 +/- 2.18 mm2 versus 21.08 +/- 6.70 mm2, plateaus 15.50 +/- 4.77 mm2 versus 35.0 +/- 3.64 mm2) and the grade (condyles 0.57 +/- 0.20 versus 1.17 +/- 0.21, plateaus 1.07 +/- 0.22 versus 2.00 +/- 0.25) of the cartilage lesions compared with the 12-week OA dogs. At the histologic level, the severity of cartilage lesions was also decreased in the tenidap-treated dogs versus the 12-week OA dogs, both on the condyles (3.43 +/- 0.54 versus 5.55 +/- 0.38) and on the plateaus (3.39 +/- 0.35 versus 5.54 +/- 0.60). All 3 OA groups showed a significant and similar level of synovial inflammation. Tenidap markedly decreased collagenase, stromelysin, and gelatinase activity, as well as the level of expression of collagenase-3 in the cartilage. Interestingly, the activity level of IL-1 in synovial fluid was also significantly reduced in the tenidap-treated dogs. CONCLUSION: Tenidap markedly reduced the severity of OA lesions, indicating the effect of this drug in decreasing the progression of disease. It appears that the drug acts by reducing the activity and/or expression of metalloproteases in cartilage, a process known to play a major role in the pathophysiology of OA lesions. This effect could be mediated by the suppressive effect of tenidap on IL-1 activity.

Animals↗
PubMed1997

In vivo suppression of early experimental osteoarthritis by interleukin-1 receptor antagonist using gene therapy.

OBJECTIVE: This study explored the therapeutic effect of interleukin-1 receptor antagonist (IL-1Ra), administered by gene transfer, on the progression of osteoarthritic (OA) lesions in an experimental dog model. METHODS: Seventeen mature mongrel dogs were divided into 3 groups. Group 1 (n = 7) had an anterior cruciate ligament (ACL) section of the right knee through a stab wound incision. Groups 2 and 3 (n = 5 per group), had an ACL section of the right knee and partial synovectomy of the left knee. Each dog's synovium was subjected to enzymatic digestion, and the synovial fibroblasts were propagated in monolayer culture. Synovial cells from each dog were transduced in vitro using the retrovirus MFG with either the Escherichia coli beta-galactosidase (lac Z) gene (group 2) or the human IL-1Ra gene (group 3). Two days after surgery, the dogs received intraarticular injections as follows: group 1 phosphate buffered saline (PBS) (2 ml); group 2 autologous cells (60 x 10(6) cells/2 ml of PBS) transduced with the lac Z gene; group 3 autologous cells transduced with the IL-1Ra gene. Synovial fluid was aspirated at 2 weeks and 4 weeks. All dogs were euthanized at 4 weeks postsurgery. The right knees were dissected, and lesions were scored for macroscopic and microscopic changes. Synovial explants were dissected and representative specimens were used for histology or were cultured for 48 hours. The levels of IL-1Ra in synovial fluid and synovial explant conditioned medium were measured by specific enzyme-linked immunosorbent assay. RESULTS: The level of IL-1Ra in synovial fluid of group 3 was 202.8 +/- 131.5 ng/ml (mean +/- SEM) at 2 weeks and 2.8 +/- 2.2 ng/ml at 4 weeks after surgery. Membrane explants isolated from dogs that received synovial cells transduced with the IL-1Ra gene (group 3) actively produced IL-1Ra (4.0 +/- 2.0 ng/gm of tissue wet weight). The severity of OA cartilage lesions was similar in groups 1 and 2. In contrast, group 3 dogs had a marked reduction in macroscopic lesion severity on the tibial plateaus (P < 0.01 for grade; P < 0.04 for size) and femoral condyles. Moreover, the histologic lesion severity was decreased on both plateaus (P < 0.06) and condyles. CONCLUSION: This study showed that a local increase in IL-1Ra production in OA knee joints by intraarticular injection of transduced synovial cells can reduce the progression of experimentally induced lesions.

Animals↗
PubMed1997

The therapeutic effects of tenidap in canine experimental osteoarthritis: relationship with biochemical markers.

OBJECTIVE: To define the dose-response relationship of the therapeutic effects of tenidap in experimental osteoarthritis (OA) and relate this to the effects on interleukin 1 (IL-1) and metalloprotease activity. METHODS: The anterior cruciate ligament of the right knee joints of 22 mongrel dogs were sectioned (ACLS) through a stab wound. Seven dogs received no treatment, 5 were treated with oral omeprazole (20 mg/day), another 5 were treated with oral tenidap (1.5 mg/kg bid) plus omeprazole (20 mg/day), and 5 received tenidap (0.5 mg/kg bid) plus omeprazole (20 mg/day). The dogs received medication for 8 weeks beginning 4 weeks after surgery. All dogs were killed 12 weeks after surgery, except for those in the first group, which were sacrificed at 4 weeks. 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, collagenase, and gelatinase activities were measured in cartilage and synovial membrane. Also, the level of IL-1 activity was measured in the synovial fluid. RESULTS: Dogs treated with tenidap at both 1.5 and 0.5 mg/kg bid exhibited a reduction in the size of osteophytes (2.25 +/- 0.30 mm, 1.70 +/- 0.65 mm, respectively) compared to the 12 weeks OA group (3.55 +/- 0.94 mm). Tenidap also significantly decreased the size and/or grade or cartilage macroscopic lesions on both condyles and plateaus. This reduction was more pronounced in dogs treated with the higher drug dose. The histological severity of cartilage lesions on femoral condyles was reduced for both tenidap doses used and significance (p < 0.04) reached for the 1.5 mg/kg bid tenidap treated dogs. Tenidap markedly and significantly reduced the level of metalloprotease activity for all 3 enzymes tested in synovial membrane (stromelysin, p < 0.03; collagenase, p < 0.02; gelatinase, p < 0.03) and in cartilage (stromelysin, p < 0.02; collagenase, p < 0.02; gelatinase, p < 0.03) with greater reduction, in general, in dogs treated with the higher dose of tenidap. IL-1 activity was significantly reduced (p < 0.02) only in animals treated with tenidap at 1.5 mg/kg bid. CONCLUSION: This study confirms that tenidap is an effective anti-osteoarthritic drug in this ACLS model where therapy was begun 4 weeks after surgery. We have defined doses that gave graded therapeutic effects, and under these conditions the effectiveness coincided with the suppression of IL-1 and metalloprotease activity, processes known to play a major role in the pathophysiology of OA lesions.

Animals↗