Pharmacological modulation of rat monocytes: in vivo effects on Ia expression and interleukin-1 production

Amlodipine reduces the antimigratory effect of diclofenac in spontaneously hypertensive rats

Amlodipine, an antihypertensive drug, and diclofenac, an antiinflammatory drug, may generally be combined, particularly in elderly patients; therefore, the potential for their interaction is high. We aim to determine if amlodipine interferes with the antimigratory effect of diclofenac. For this, male spontaneously hypertensive rats (SHRs) were treated with either diclofenac (1 mg.kg.d, 15 d) alone or combined with amlodipine (10 mg.kg.d, 15 d). Leukocyte rolling, adherence, and migration were studied by intravital microscopy. Diclofenac did not change (180.0 +/- 2.3), whereas amlodipine combined (163.4 +/- 5.1) or not (156.3 +/- 4.3) with diclofenac reduced the blood pressure (BP) levels in SHR (183.1 +/- 4.4). Diclofenac and amlodipine reduced leukocyte adherence, migration, and ICAM-1 expression, whereas only diclofenac reduced rolling leukocytes as well. Combined with amlodipine, the effect of the diclofenac was reduced. Neither treatment tested increased the venular shear rate or modified the venular diameters, number of circulating leukocytes, P-selectin, PECAM-1, L-selectin, or CD-18 expressions. No difference could be found in plasma concentrations of both drugs given alone or in association. In conclusion, amlodipine reduces leukocyte migration in SHR, reducing endothelial cell ICAM-1 expression. Amlodipine reduces the effect of the diclofenac, possibly by the same mechanism. A pharmacokinetic interaction as well as an effect on the other adhesion molecules tested could be discarded.

Losartan attenuates the antimigratory effect of diclofenac in spontaneously hypertensive rats

Many patients with hypertension, particularly elderly patients, take nonsteroidal antiinflammatory drugs (NSAIDs) and antihypertensive agents. However, few studies describe the effect of the association of antihypertensive agents with NSAIDs on inflammatory response in hypertension. To investigate this, spontaneously hypertensive rats (SHRs) were treated with either diclofenac alone or diclofenac combined with losartan (an AT1 angiotensin II antagonist). The leukocyte-endothelial interaction was then observed using intravital microscopy. Blood pressure of SHR (169.6+/-3.6) was increased by diclofenac (186.4+/-2.9), reduced by losartan (152.6+/-3.5), and reduced by the combination of the 2 (158.9+/-3.7). All the treatments tested reduced the number of rollers, adherent and migrated leukocytes, and the expression of endothelial intercellular adhesion molecule-1 and P-selectin. The association of losartan reduced the effect of diclofenac on leukocyte migration. Neither treatment tested increased the venular shear rate or modified the venular diameters, number of circulating leukocytes, and L-selectin expression on granulocytes. The reduction of CD11/CD18 expression induced by diclofenac alone was hindered by losartan. A pharmacokinetic interference between losartan and diclofenac was ruled out since no significant differences were observed in the plasma concentrations of each drug when they were associated. In conclusion, although diclofenac does not interfere with the losartan antihypertensive effect, losartan attenuates the effect of diclofenac has on leukocyte behavior and expression of adhesion molecules. Losartan has an antimigratory effect, reducing leukocyte migration by reducing ICAM-1 and P-selectin expression. Losartan may hinder the full expression of the antimigratory effect of diclofenac.

Enalapril Interferes with the Effect of Diclofenac on Leucocyte-Endothelium Interaction in Hypertensive Rats

Nonsteroidal anti-inflammatory drugs are known to attenuate the effects of some antihypertensive agents. However, the effect these drugs have on leukocyte migration when combined with antihypertensive agents has not been studied. To investigate this effect, we treated spontaneously hypertensive rats with saline, diclofenac, enalapril, or diclofenac combined with enalapril and observed leukocyte-endothelium interaction. Blood pressure was increased by diclofenac, reduced by enalapril and reduced by the combination of the two. Diclofenac did not interfere with the blood pressure-lowering effect of enalapril. Internal spermatic fascia venules were observed using intravital microscopy. Diclofenac reduced rollers, whereas enalapril, alone or combined with diclofenac, had no significant effect on rollers. All treatments reduced adherent and migrated leukocytes and expression of endothelial intercellular adhesion molecule-1. Venular shear rate, venular diameters, number of circulating leukocytes, and post-leukotriene B4 expression of l-selectin and CD11/CD18 integrin in leukocytes were unaffected by any treatment. Expression of P-selectin was reduced by diclofenac and unaffected by enalapril, even when combined with diclofenac. Our data suggest that, although diclofenac does not interfere with the enalapril anti-hypertensive effect, enalapril interferes with the effect diclofenac has on leukocyte rolling and endothelial P-selectin expression. Involvement of reduced endothelial intercellular adhesion molecule-1 expression might explain the lower numbers of adherent and migrated leukocytes. The anti-inflammatory properties of a nonsteroidal anti-inflammatory drug could therefore be attenuated in hypertensive patients receiving an angiotensin-converting enzyme inhibitor.