Effect of glucocorticoids on nasal polyposis, with detection of inflammatory response by measurement of nitric oxide levels in nasal polyp tissue.

OBJECTIVE: To investigate endoscopic staging, and nitric oxide levels in the polyp tissue, in patients with nasal polyposis undergoing glucocorticoid therapy. METHODS: Nasal polyposis was evaluated using endoscopic staging and measurement of polyp tissue nitric oxide levels (chemiluminescence method). Forty-five nasal polyposis patients received either nasal therapy (n = 15), oral therapy (n = 15) or combined therapy (n = 15). Pre-treatment and post-treatment staging and nitric oxide levels were evaluated. RESULTS: Endoscopic grading indicated significant post-treatment staging improvements in the oral (p = 0.016) and combined (p = 0.016) groups. Post-treatment staging differed significantly between the three groups (p = 0.041), with greater improvements in the oral and combined groups. All groups showed significantly lower post-treatment nitric oxide levels, compared with baseline, but post-treatment levels did not differ significantly between groups. A significant association was found between treatment response and nitric oxide level alteration. CONCLUSION: This study demonstrates the favourable effects of glucocorticoids on nasal polyposis, and alteration in nitric oxide tissue levels post-treatment. Nitric oxide level in nasal polyp tissue could be an indicator of treatment response, and may aid surgical decision-making by detecting cases that probably will not respond to medical treatment.

Plasma markers of NO synthase activity in women after ovarian hyperstimulation: influence of estradiol on ADMA.

The beneficial effects of estrogen on vasculature are partially explained by an estrogen-induced increase in nitric oxide (NO) synthesis. Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of NO synthase. In the present study, the effect of 17beta-estradiol (E2) on ADMA and NO synthesis was investigated both in vivo and in vitro. Plasma NO and ADMA levels were measured in healthy women at a low menstrual estrogenic stage (E2 < 100 pg/ml) and in women who were undergoing ovarian hyperstimulation (E2 > 2000 pg/ml) before in vitro fertilization embryo transfer. Primary human umbilical vein endothelial cell (HUVEC) cultures were incubated with and without 100 nM E2 for 24 hours and the NO and ADMA levels of the media were measured. A nitric oxide analyzer was used for the detection of NO metabolites. ADMA and L-arginine were measured by high-performance liquid chromatography after precolumn derivatization with o-phthaldialdehyde. The IVF patients with high plasma E2 concentrations had significantly lower (48%, n = 12) plasma ADMA and higher (56%, n = 14) NO levels than the women at a low estrogenic stage. The incubation of HUVEC cultures with estradiol resulted in a significant decrease (47%, n = 10) in ADMA and an increase (46%, n = 10) in NO concentration in the culture media. Estradiol, by reducing ADMA, may therefore facilitate NO synthesis in endothelial cells. The protective effects of estradiol on vasculature may partly be related to a reduction in ADMA levels.

Acute Effects of 17ß-Estradiol and ATP on Endothelial Cells; Effects of Genistein and PMA on Calcium Response.

Various studies have shown that 17ß-estradiol (E2), has acute effects on cardiovascular system in addition to its genomic effect. Acute administration of E2 had been shown to increase intracellular free calcium concentration (Ca+2)i in human umbilical vein endothelial cells (HUVEC). The present study investigates the signalling pathway responsible for Ca+2 response to E2. In the study, the effect of E2 on phosphoinositide turnover was investigated by use of Dowex-1 anion-exchange columns after labeling cells with myo(3H)inositol. Additionally, the effects of tyrosine phosphorylation inhibitor genistein and protein kinase C activator 4ß-phorbol-12ß-myristate-13-acetate (PMA) on the Ca+2 response to E2 and ATP were investigated and compared in fura-2 loaded HUVEC. The data demonstrates that E2 treatment causes 45% increase in inositol phosphate production in parallel to increases in (Ca+2)i. Genistein and PMA inhibit the Ca+2 response to E2 ~75%, 49%, while they inhibit the response to ATP ~62%, 73% respectively. Our data suggests the involvement of PLC in the signaling stimulated by E2 and indicate the involvement of tyrosine phosphorylation and PKC. Differences in the effect of the inhibitors on E2- and ATPinduced responses suggest that there may be differences in the upstream signaling initiated by E2 and ATP, such as different roles for tyrosine phosphorylation.