Modified histamine-induced NO-mediated relaxation in resistance arteries in pre-eclampsia

Diagnostic features of mild cellulitis phlegmon in patients with rheumatoid arthritis treated with tocilizumab: a report of two cases

Two cases of subcutaneous soft tissue infection in 30 RA patients treated with tocilizumab are reported. In both patients, local redness, swelling, and heat were observed around the affected site. WBC spikes and such local findings were suggested to be clinically useful for the early detection of low-grade subcutaneous infection in RA patients whose disease is tightly controlled with tocilizumab. Of note, the C-reactive protein (CRP) level and temperature lacked clinical utility for such detection.

Phosphodiesterase-5 inhibitors and omental and placental small artery function in normal pregnancy and pre-eclampsia

OBJECTIVES

In pre-eclampsia (PE), endothelium-dependent function of myometrial small arteries is markedly attenuated. The residual PE response is wholly NO mediated. We have previously demonstrated that PDE5 inhibition can improve endothelial function in myometrial small arteries from women with PE. We aimed to assess whether the effect of PDE5 inhibition in PE was myometrial artery specific.

STUDY DESIGN

Small arteries were dissected from omental biopsies obtained at Caesarean section from normal pregnant women (NP, N = 20) and women with PE (N = 11). Chorionic plate small arteries were dissected from NP (N = 13) and PE (N = 11) placentae. Vasoconstriction (arginine vasopressin or thromboxane-mimetic U46619) and endothelial-dependent relaxation were assessed by wire and pressure myography. Constriction/relaxation curves were repeated post 1h incubation with PDE5 inhibitors UK-343664 or sildenafil citrate (0, 10 or 100 nM).

RESULTS

Omental artery constriction was increased in PE. Omental vessel constriction was unaffected by PDE5 inhibition. Sildenafil citrate improved bradykinin-induced but not acetylcholine-induced relaxation of omental small arteries from NP women. PDE5 inhibition did not alter relaxation of omental arteries from women with PE. Placental small arteries were unaffected by PDE5 inhibition.

CONCLUSION

Use of PDE5 inhibitors does not significantly alter endothelial-dependent relaxation in omental or placental small arteries from PE women.

L-arginine attenuates hypertension in pregnant rats with reduced uterine perfusion pressure

A chronic reduction in uterine perfusion pressure in the pregnant rat is associated with significant elevations in mean arterial pressure, proteinuria, and reductions in kidney function as is chronic nitric oxide blockade, suggesting that nitric oxide deficiency may contribute to the clinical manifestations of preeclampsia. The purpose of this study was to determine whether supplementation with L-arginine, the precursor for nitric oxide, attenuates the hypertension produced in response to a chronic reduction in uterine perfusion pressure in the pregnant rat. Reduced uterine perfusion was initiated at day 14 of gestation with arterial pressure determined at day 19 of gestation in conscious, chronically instrumented rats. Arterial pressure was significantly elevated in pregnant rats with chronic reductions in uterine perfusion as compared with pregnant control rats (132+/-2 versus 109+/-2 mm Hg, P<0.01, respectively). Treatment with L-arginine (2%) in the drinking water was initiated at day 10 of gestation. l-arginine supplementation resulted in a significant decrease in arterial pressure in both pregnant rats with reduced uterine perfusion pressure (113+/-2 mm Hg treated, P<0.01 versus untreated pregnant with reduced uterine perfusion pressure) and pregnant control (97+/-3 mm Hg treated, P<0.01 versus untreated pregnant) rats. However, supplementation with L-arginine decreased blood pressure by 19 mm Hg in pregnant with reduced uterine perfusion pressure (untreated versus treated) as compared with 12 mm Hg in pregnant (untreated versus treated) rats. Thus, these results suggest that l-arginine supplementation may be beneficial in attenuating the hypertension in preeclampsia.

The pharmacology of nitric oxide in the peripheral nervous system of blood vessels

Unanticipated, novel hypothesis on nitric oxide (NO) radical, an inorganic, labile, gaseous molecule, as a neurotransmitter first appeared in late 1989 and into the early 1990s, and solid evidences supporting this idea have been accumulated during the last decade of the 20th century. The discovery of nitrergic innervation of vascular smooth muscle has led to a new understanding of the neurogenic control of vascular function. Physiological roles of the nitrergic nerve in vascular smooth muscle include the dominant vasodilator control of cerebral and ocular arteries, the reciprocal regulation with the adrenergic vasoconstrictor nerve in other arteries and veins, and in the initiation and maintenance of penile erection in association with smooth muscle relaxation of the corpus cavernosum. The discovery of autonomic efferent nerves in which NO plays key roles as a neurotransmitter in blood vessels, the physiological roles of this nerve in the control of smooth muscle tone of the artery, vein, and corpus cavernosum, and pharmacological and pathological implications of neurogenic NO have been reviewed. This nerve is a postganglionic parasympathetic nerve. Mechanical responses to stimulation of the nerve, mainly mediated by NO, clearly differ from those to cholinergic nerve stimulation. The naming "nitrergic or nitroxidergic" is therefore proposed to avoid confusion of the term "cholinergic nerve", from which acetylcholine is released as a major neurotransmitter. By establishing functional roles of nitrergic, cholinergic, adrenergic, and other autonomic efferent nerves in the regulation of vascular tone and the interactions of these nerves in vivo, especially in humans, progress in the understanding of cardiovascular dysfunctions and the development of pharmacotherapeutic strategies would be expected in the future.

Effect of tumour necrosis factor-alpha and interleukin 1beta on endothelium-dependent relaxation in rat mesenteric resistance arteries in vitro

1. Pre-eclampsia is associated with elevated proinflammatory cytokine levels and endothelial dysfunction. This study examined the effect of two cytokines, tumour necrosis factor-alpha (TNF) and interleukin-1beta (IL-1) on endothelium-dependent relaxation in response to acetylcholine (ACH), bradykinin (BK) and histamine (HIS) in rat mesenteric small arteries in vitro. 2. Rat mesenteric arteries were mounted in an isometric myograph. Tone was induced with phenylephrine (PE) or a depolarizing solution containing 80 mM KCl (K(80)). Relaxation was measured in response to ACH, BK, HIS and sodium nitroprusside (SNP), an endothelium-independent relaxant. Inhibition of NO synthase by a combination of N(omega)-monomethyl-L-arginine (L-NMMA) and N(omega)-nitro-L-arginine methyl ester (L-NAME) significantly inhibited relaxation in response to ACH and BK. Addition of an inhibitor of cyclooxygenase, indomethacin, had no additional effect when added to L-NMMA and L-NAME. Inhibition of endothelium-derived hyperpolarizing factor (EDHF) by K(80) partially reduced responses to ACH and BK. Inhibition of HIS-induced relaxation was more marked with K(80). L-NMMA and L-NAME largely abolished the remaining relaxation to ACH, BK and HIS in arteries contracted with K(80). 3. Preincubation with TNF for 30 min caused an inhibition of relaxation in response to ACH and BK in arteries contracted with PE. Responses to HIS and SNP were not affected by TNF under these conditions. TNF also inhibited ACH-induced relaxation in arteries contracted with K(80). IL-1 had no effect on responses to ACH and the combination of TNF and IL-1 was not more effective than TNF alone. 4. The inhibitory effect of TNF on ACH-induced relaxation was abolished by coincubation with superoxide dismutase (SOD) and was not seen if NO synthase was inhibited by L-NMMA and L-NAME. 5. TNF inhibits the NO-dependent component of endothelium-dependent relaxation in response to ACH and BK, but does not inhibit the EDHF-dependent component. This effect may be attributable to the ability of TNF to increase levels of superoxide anions (O(2)(-)) and the ability of O(2)(-) to inactivate NO. This mechanism could contribute to the endothelial dysfunction seen in situations where TNF is elevated, such as pre-eclampsia.