Methotrexate inhibition of bone mineral density increase in growing rabbits: prevention by folinic acid.

OBJECTIVE: Methotrexate (MTX) action on bone metabolism is as yet not completely understood. The results of clinical studies are controversial, since it is difficult to distinguish the side effects of MTX from those of the primary disease. This study assessed the effect of MTX, with and without folinic acid supplementation, on bone mineral density in growing normal rabbits. METHODS: Three groups of young NZW growing female rabbits were treated with: saline (n = 6) or MTX (0.25 mg/kg/week, n = 5) or MTX (same dose as above) plus folinic acid (0.25 mg/kg/week, n = 6) for a period of 3 months. The dose, duration and frequency of MTX administration were similar to the treatment of RA patients. The animals were submitted to dual-energy absorptiometry densitometry (HologicQDR 2000) before and after treatment; total body and L4-L5 BMD were evaluated. Histomorphometric analysis (L4 vertebrae) was also performed. RESULTS: Growing control rabbits showed increased total body BMD from a baseline of 0.180 +/- 0.006 to 0.198 +/- 0.007 gm/cm2 (mean +/- S.E.M, p < 0.006). In contrast, no increase in BMD (0.182 +/- 0.006 versus a baseline of 0.184 +/- 0.004, ns) was observed in the group treated with MTX, while the addition of folinic acid resulted in an increase in BMD values similar to controls, from a baseline of 0.181 +/- 0.004 to 0.198 +/- 0.003, p < 0.02), thus preventing adverse MTX bone effects. Average percent variations in BMD were +7.7%, -1% and +8.4% respectively. Spine (L4-L5) BMD showed analogous results, in line with the histomorphometric data. CONCLUSION: These results strongly support a deleterious action of MTX on bone metabolism, which is prevented by folinic acid supplementation. The potential clinical implications of our data are particularly significant for paediatric therapy.

Methotrexate as a preferential cyclooxygenase 2 inhibitor in whole blood of patients with rheumatoid arthritis.

OBJECTIVE: To investigate the regulation of whole-blood cyclooxygenase-1 and -2 (COX-2 and COX-1) activities by methotrexate (MTX) in rheumatoid arthritis (RA) patients. METHODS: Whole blood was withdrawn from nine healthy volunteers, 12 RA patients treated with MTX (RA/MTX) and six RA patients treated with chloroquine (RA/CQ). COX-1 activity was quantified as platelet thromboxane B(2) production in unstimulated blood and COX-2 activity was measured as prostaglandin E(2) (PGE(2)) production in whole blood stimulated with LPS. Thromboxane B(2) and PGE(2) were measured by radioimmunoassay. We studied the drug effect in vitro by direct incubation of MTX with blood obtained from normal donors. Ex vivo assays were performed with blood collected from RA/MTX and RA/CQ patients. The influence of serum factors on enzyme activities was analysed in blood collected from normal donors and incubated with RA/MTX, autologous or heterologous serum. RESULTS: In vitro assays showed no direct action of MTX on the activity of either enzyme. Assays performed with blood from RA/MTX patients showed preferential inhibition of COX-2 activity (PGE(2) = 10.11 +/- 2.42 ng/ml) when compared with blood of normal donors (PGE(2) = 37.7 +/- 4.36 ng/ml; P = 0.001). Inhibition of COX-2 activity was also observed when blood of normal donors was co-incubated with RA/MTX serum. CONCLUSION: Our results clearly show that the anti-inflammatory action of low-dose MTX is partly mediated by a serum factor induced by MTX or a MTX metabolite that preferentially inhibits the activity of COX-2.

Interrelationship of the kinin system, nitric oxide and eicosanoids in the antigen-induced arthritis in rabbits.

The aim of the present study was to investigate the interrelationship of the kinin system, nitric oxide and eicosanoids in the acute phase of antigen-induced arthritis (AIA) in rabbits. The arthritis was induced in immunized rabbits and the following parameters were evaluated 24 hours later: leukocyte influx (total and differential white cell count), vascular permeability (Evans's blue method), and synovial PMN cell infiltrate. PGE2 and LTB4 (radioimmunoassay) levels were quantified in the synovial fluid. The animals were pre-treated with 20mg/kg/day during 14 days with L-NAME or D-NAME and/or Enalapril (0.12 mg/kg/day-14 days), and/or the B2 antagonist of Bradykinin HOE 140 (0.9 mg/kg). Our results showed that L-NAME was effective in the prevention of AIA with reduction of all Inflammatory parameters analyzed. Enalapril partially reverted the L-NAME anti-inflammatory effects. The simultaneous treatment with HOE 140 abolished this reversion and returned the inflammatory parameters to the levels observed in L-NAME treated animals. Our results suggest that pressoric alterations induced by L-NAME could not account for all its anti-inflammatory action in this model of experimental arthritis. Additionally the contribution of the kinin system in AIA was characterized as well as its interaction with eicosanoids and nitric oxide.

[Intra-articular nitric oxide levels in patients with rheumatoid arthritis]. / Níveis intra-articulares de óxido nítrico em pacientes com doença reumatóide.

The aim of this study was the appraisal of the nitrite and nitrate levels in the synovial fluid of patients with rheumatoid arthritis (RA). The synovial fluid of patients with osteoarthritis (OA) was also evaluated by comparison. Demographic characteristics such as age and sex, and clinical and laboratorial parameters like duration of disease, functional class and erythrocyte sedimentation rate (ESR) were evaluated too. In the synovial fluid of all patients the total and differential leukocyte count, and the nitrite and nitrate levels determined by Griess reaction were analyzed. The results were statistically analyzed by Student's t test and correlation test. We found a significant increase in the intraarticular nitrite and nitrate levels in patients with RA when compared with OA patients (30.68 +/- 2.94 microM x 16.15 +/- 2.73 microM). We did not find any correlation between intraarticular nitrite and nitrate levels and the ESR or the total and differential leukocyte count in the RA synovial fluid. In this study we clearly found an increase in the intraarticular nitrite and nitrate levels in patients with rheumatoid arthritis.

Nitric oxide synthase inhibitor influences prostaglandin and interleukin-1 production in experimental arthritic joints.

OBJECTIVE: To assess involvement of nitric oxide (NO) in the increase in eicosanoid and interleukin- 1 (IL-1) levels in the synovial fluid during antigen-induced arthritis (AIA) in rabbits treated with a competitive inhibitor of NO synthesis. SUBJECTS: Thirteen New Zealand White rabbits were sensitized with 5 mg of methylated bovine serum albumin (mBSA). Arthritis was induced in the knee joint by injecting 0.5 ml of a sterile solution of mBSA (2 mg/ml) into the intra-articular cavity. TREATMENT: Prior to the induction of arthritis, the animals received N-Omega-Nitro-L-Arginine Methyl Ester (LNAME) or N-Omega-Nitro-D-Arginine Methyl Ester (DNAME) for 2 weeks, both at a dose of 20 mg/kg/day mixed with drinking water. METHODS: Leukocyte efflux (total and differential white cell count), vascular permeability (Evans's blue method), synovial PMN cell infiltrate, and total nitrite (NO2.)/nitrate (NO3.) (HPLC), PGE2, TxB2, LTB4 (radioimmunoassay), and IL-1 beta (ELISA) levels were quantified in the synovial fluid. RESULTS: LNAME but not DNAME significantly suppressed leukocyte efflux and protein leakage into the articular cavity as well as synovial PMN cell infiltrate. Total NO2./NO3., PGE2 and IL-1 beta levels were significantly reduced in the synovial fluid of LNAME treated animals. TxB2 and LTB4 were not affected by LNAME treatment. CONCLUSION: These data clearly show NO involvement in the IL-1-induced PGE2 production in the synovial fluid of antigen-induced arthritis in rabbits.

[Clinical and laboratory diagnosis of heart disease in systemic lupus erythematosus]. / Avaliação clínica e laboratorial da cardiopatia no lúpus eritematoso sistêmico.

PURPOSE: To examine heart disease in the systemic lupus erythematosus (SLE) and the association of cardiac abnormalities with anticardiolipin antibodies (ACL). METHODS: Sixteen patients with active SLE disease (group I) were compared with 14 patients without disease activity (group II). A control group of 10 healthy subjects were also evaluated. Patients were subjected to cardiovascular history and physical examination as well as electrocardiogram, thoracic x-ray, two-dimensional and Doppler echocardiogram, and ACL serum determination (ELISA). RESULTS: Myocardial disease characterized by tachycardia, heart failure or echocardiographic abnormalities was shown by 75% of patients in the group I. It was associated with ACL positive in 27.2% of these patients. Pericardial and valvular involvement were observed in 25% of patients in group I. Group II showed myocardial involvement in 21.4% of patients without positive ACL. CONCLUSION: Myocardial disease was the most frequent heart involvement in active SLE, and we did not found any association between SLE heart disease and positive anticardiolipin antibodies.

Low dose methotrexate decreases intraarticular prostaglandin and interleukin 1 levels in antigen induced arthritis in rabbits.

OBJECTIVE: To investigate the effects of methotrexate (MTX) on inflammation variables of antigen induced arthritis (AIA) in rabbits, such as protein leakage to the articular cavity, synovial fluid (SF) leukocyte count, synovial membrane polymorphonuclear (PMN) cell infiltrate, and intraarticular production of eicosanoids and interleukin 1 (IL-1). Dexamethasone and indomethacin were used for comparison. METHODS: NZW rabbits were treated with the following drugs: MTX (0.25 mg/kg), dexamethasone (0.15 mg/kg), indomethacin (4 mg/kg), and sterile saline (control group). All drugs were given by intramuscular route before arthritis was induced and the animals were sacrificed 4 or 24 h later. Leukocyte migration, protein leakage (Evans blue method), synovium PMN cell infiltrate, and intraarticular concentration of prostaglandin E2 (PGE2), thromboxane B2 (TXB2), leukotriene B4 (LTB4) (radioimmunoassay), and IL-1 beta (ELISA) were quantified in SF. RESULTS: Significant reduction of leukocyte migration and protein leakage was observed in the joint fluid of all treated animals. Decrease in the intensity of synovium PMN cell infiltrate also occurred with all treatments. Intraarticular PGE2, TXB2, and IL-1 beta were significantly reduced after 4 h of arthritis induction in animals treated with MTX and dexamethasone. Treatment with indomethacin reduced only PGE2 and TXB2 in SF. Treatments did not change SF IL-1 beta concentration 24 h after arthritis induction. Treatment with dexamethasone increased inflammatory variables and SF LTB4 concentration 24 h after the synovial cavity was challenged with antigen. CONCLUSION: Our results show that MTX, like dexamethasone, reduces the intensity of leukocyte afflux, protein leakage, synovial membrane PMN cell infiltrate, as well as the intraarticular production of PGE2, TXB2, and IL-1 beta in the early phase of antigen induced arthritis in rabbits.

Poliarterite nodosa na infancia. Descricao de caso. / Polyarteritis nodosa in childhood. Report of a case

Relata-se poliarterite nodosa na infancia associada a endocardite infecciosa descrita em seus aspectos clinicos laboratoriais e histopatologicos.Discutem-se as dificuldades de diagnostico, etiopatogenia, assim como o envolvimento neurologico central e a resposta a terapeutica instituida.com dois modelos e resistencia, sensive