Massimo Realacci

Nitric oxide synthases in normal and benign hyperplastic human prostate: Immunohistochemistry and molecular biology

The expression of nitric oxide synthase (NOS) isoforms has been investigated in normal (three subjects) and benign hyperplastic prostate (ten patients) by immunohistochemistry and reverse transcriptase‐polymerase chain reaction (RT‐PCR). The inducible NOS (iNOS or NOS‐2) is not detected in normal prostate, while it is expressed in the prostate of all benign prostatic hyperplasia (BPH) patients, even in the absence of prostatitis or systemic signs of an inflammatory condition. This suggests that sex hormones may be involved in iNOS induction and that there may be a role for NO in the pathogenesis of BPH. Constitutive NOSs (nNOS and eNOS) are expressed in both normal and hyperplastic prostate and are co‐expressed in epithelial cells. eNOS, however, is present mainly in the basal layer cells; nNOS seems abundantly expressed in the more superficial cells of the affected prostate. This indicates that the switching between the two constitutive isoforms may be part of the usual process of cell differentiation from the basal to the secretory layer of the epithelium. Copyright

17β-Estradiol modulates the macrophage migration inhibitory factor secretory pathway by regulating ABCA1 expression in human first-trimester placenta

Successful pregnancy involves a series of events, most of them mediated by hormones and cytokines. Estrogens, besides being important for placental growth and embryo development, have a marked effect on the immune system exerting either pro- or anti-inflammatory properties. Numerous studies suggest that estrogens directly affect cellular function, including cytokine production. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in pregnancy, particularly during the earlier stages of placentation. Since reports on mice have shown that estrogens modulate MIF, herein we investigated the effect of estrogens on human placental MIF. By using an in vitro model of first-trimester chorionic villous explants, we found that 17beta-estradiol (E(2)) was able to modulate the release of MIF in a dose-dependent manner (10(-12) vs. 10(-9) M, P < 0.05; 10(-9) vs. 10(-5) M, P < 0.05; 10(-12) vs. 10(-5) M, P < 0.001). Unlike MIF release, no significant change in tissue MIF protein or MIF mRNA was observed. We showed evidence that E(2) concentrations (10(-9) and 10(-5) M) act on placental tissue downregulating the mRNA and protein expression of the ATP-binding cassette transporter protein A1, a membrane transporter involved in MIF secretion. These findings emphasize the mutual cooperation between hormones and cytokines and suggest that increasing estrogen levels with advancing gestation may have a major role in regulating placental MIF secretion.

Hormonal regulation of cytokine release by human fetal membranes at term gestation: effects of oxytocin, hydrocortisone and progesterone on tumour necrosis factor-α and transforming growth factor-β 1 output

Inflammatory cytokines can play an important role in the biomolecular processes leading to labour by regulating prostaglandin production in intrauterine tissues. In the setting of intrauterine infection, an increased production of these cytokines by placenta, decidua and fetal membranes occurs and is responsible for the onset and maintenance of preterm labour. However, the factors involved in the control of cytokine release by these tissues in normal pregnancy at term are still largely unknown. We investigated the possibility that the synthesis and release of tumour necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) by human fetal membranes at term gestation is regulated by several hormones potentially involved either in the maintenance of pregnancy or in the parturitional process. In the present study, the effects of hydrocortisone, progesterone and oxytocin on TNF-alpha and TGF-beta1 release by explants of fetal membranes at term gestation were evaluated. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to assess the effect of the above hormones on mRNA expression; TNF-alpha and TGF-beta1 release in culture medium was quantitifed by ELISA assays. Results show that both tissue mRNA expression for TNF-alpha and TNF-alpha release in culture medium were significantly increased by oxytocin, but not by hydrocortisone and progesterone. On the contrary, all the hormones tested increased both tissue TGF-beta1 mRNA expression and release in culture medium. These findings suggest that TNF-alpha and TGF-beta1 production by human fetal membranes in uncomplicated pregnancy at term is selectively modulated by oxytocin, hydrocortisone and progesterone.

Estradiol 17-β and Progesterone Modulate Inducible Nitric Oxide Synthase and High Mobility Group Box 1 Expression in Human Endometrium

The aim of the present study is to investigate the effects of ovarian sex steroid hormones on the expression and the release of several locally active substances by human endometrium. Specific objectives are (1) to ascertain if estradiol 17-β (E2) and progesterone modulate inducible nitric oxide synthase (iNOS) expression and nitric oxide release; (2) to determine whether human endometrium can express High Mobility Group Box 1 (HMGB1), a multifunctional cytokine, and whether sexual steroid hormones can modulate this expression; and (3) to evaluate whether nitric oxide can influence HMGB1 expression in this tissue. Endometrial tissue was obtained from 40 healthy premenopausal women who underwent hysteroscopy for suspected benign gynecological conditions. Endometrium was incubated with E2, progesterone, or sodium nitroprusside, a nitric oxide donor. Nitrite assay was used to quantify stable nitric oxide metabolites in culture medium, and Western blot analysis was used to detect iNOS and HMGB1. Incubation of endometrium with E2 results in an increase in iNOS expression and nitric oxide metabolite production. The opposite effect is obtained by incubating tissues with progesterone. HMGB1 is expressed by human endometrium, and its expression is increased by E2 and decreased by progesterone. Incubation with sodium nitroprusside results in a reduction in HMGB1 expression. Both E2 and progesterone modulate iNOS expression and nitric oxide production in human endometrium. HMGB1 is expressed in the human endometrium, and its expression is modulated by E2, progesterone, and nitric oxide.

Oxytocin modulates Nitric oxide generation by Human fetal membranes at term pregnancy

Problem:  Nitric oxide (NO), an important mediator of the inflammatory response, is involved in several reproductive processes including pregnancy and labor. Uterus, placenta and fetal membranes are significant sources of NO. Presently, there is no information on factors regulating NO production by fetal membranes.

Effects of prolonged exposure to pancreatic glucagon on the function, antigenicity and survival of isolated human islets.

Certain clinical conditions are associated with inappropriately high levels of circulating glucagon. To date, little information is available about the direct effects of prolonged exposure of human islet cells to pancreatic glucagon. In the present study we evaluated the function, antigenicity and survival of human islets exposed for 24 h to human pancreatic glucagon.

Expression of NOS–2, COX–2 and Th1/Th2 cytokines in migraine

AbstractNitric oxide (NO) probably plays an important role in the pathogenesis of migraine without aura (MWA). As the activation of NO–ergic cascade has been shown to be closely linked to cyclooxygenase pathway and to cause some differences in peripheral blood lymphocyte populations, we investigated if the Th1/Th2 balance in peripheral blood of MWA patients was affected in comparison to controls. Twenty–six MWA patients and 10 healthy controls (C) were enrolled in this study. Blood samples were taken at baseline (T0) and during an induced migraine attack (T1). Total RNA from human peripheral blood lymphocytes (PBLs) was isolated and reverse–transcribed to prepare complementary DNA. COX–2, NOS–2 and β–actin were amplified using PCR. PBLs from patients and controls were stimulated with phorbol 12–myristate 13–acetate plus ionomycin in the presence of brefeldin A. Cells were surface–stained with fluorochrome–conjugated anti–CD3 and anti–CD8 monoclonal antibodies (mAbs) and intracellularly stained with fluorochrome– conjugated anti–IFN–γ or anti–IL–4 mAbs. The level of cytokine expression was analyzed by gating on the CD4+ lymphocyte subset. Th1 and Th2 type cytokines (IFN–γ, IL–2, IL–4) were directly assayed in serum by ELISA. Preliminary results indicate that NOS–2 was upregulated in MWA patients at basal time if compared to controls, whereas after NOD administration NOS–2 was significantly decreased. COX–2 was upregulated in MWA patients at basal time and it had an opposite trend after NOD administration. The homeostatic Th1/Th2 balance defined by the IFN–γ or IL–4 cytokine expression was unchanged in MWA patients in comparison to controls, and NOD administration did not affect that pattern. The cell activation machinery was not altered after mitogenic activation, as shown by CD69 expression level. Cytokine serum levels showed no significant changes in all studied situations. This study confirms the relevance of the NOS/COX system in MWA but, in contrast with previous studies, excludes their effect and activation on peripheral cytokine production. More sophisticated experimental models are needed to investigate the ability of NOS/COX to activate migraine pain.