Akt-dependent phosphorylation of endothelial nitric-oxide synthase mediates penile erection

In the penis, nitric oxide (NO) can be formed by both neuronal NO synthase and endothelial NOS (eNOS). eNOS is activated by viscous drag/shear stress in blood vessels to produce NO continuously, a process mediated by the phosphatidylinositol 3-kinase (PI3kinase)/Akt pathway. Here we show that PI3-kinase/Akt physiologically mediates erection. Both electrical stimulation of the cavernous nerve and direct intracavernosal injection of the vasorelaxant drug papaverine cause rapid increases in phosphorylated (activated) Akt and eNOS. Phosphorylation is diminished by wortmannin and LY294002, inhibitors of PI3-kinase, the upstream activator of Akt. The two drugs also reduce erection. Penile erection elicited by papaverine is reduced profoundly in mice with targeted deletion of eNOS. Our findings support a model in which rapid, brief activation of neuronal NOS initiates the erectile process, whereas PI3-kinase/Akt-dependent phosphorylation and activation of eNOS leads to sustained NO production and maximal erection.

Phospholipase C gamma 1 is a physiological guanine nucleotide exchange factor for the nuclear GTPase PIKE

Phospholipase C gamma 1 (PLC-gamma 1) hydrolyses phosphatidylinositol-4,5-bisphosphate to the second messengers inositol-1,4,5-trisphosphate and diacylglycerol. PLC-gamma 1 also has mitogenic activity upon growth-factor-dependent tyrosine phosphorylation; however, this activity is not dependent on the phospholipase activity of PLC-gamma 1, but requires an SH3 domain. Here, we demonstrate that PLC-gamma 1 acts as a guanine nucleotide exchange factor (GEF) for PIKE (phosphatidylinositol-3-OH kinase (PI(3)K) enhancer). PIKE is a nuclear GTPase that activates nuclear PI(3)K activity, and mediates the physiological activation by nerve growth factor (NGF) of nuclear PI(3)K activity. This enzymatic activity accounts for the mitogenic properties of PLC-gamma 1.

Pike. A nuclear gtpase that enhances PI3kinase activity and is regulated by protein 4.1N

While cytoplasmic PI3Kinase (PI3K) is well characterized, regulation of nuclear PI3K has been obscure. A novel protein, PIKE (PI3Kinase Enhancer), interacts with nuclear PI3K to stimulate its lipid kinase activity. PIKE encodes a 753 amino acid nuclear GTPase. Dominant-negative PIKE prevents the NGF enhancement of PI3K and upregulation of cyclin D1. NGF treatment also leads to PIKE interactions with 4.1N, which has translocated to the nucleus, fitting with the initial identification of PIKE based on its binding 4.1N in a yeast two-hybrid screen. Overexpression of 4.1N abolishes PIKE effects on PI3K. Activation of nuclear PI3K by PIKE is inhibited by the NGF-stimulated 4.1N translocation to the nucleus. Thus, PIKE physiologically modulates the activation by NGF of nuclear PI3K.

Inositol polyphosphate multikinase is a nuclear PI3-kinase with transcriptional regulatory activity

Phosphatidylinositol 3,4,5-trisphosphate is a major intracellular messenger molecule thought to be formed almost exclusively by cytosolic, wortmannin-inhibited phosphoinositide 3-kinase family members. Inositol polyphosphate multikinase was identified as an enzyme that generates a series of water-soluble inositol phosphates. We now report the robust, physiologic, and evolutionarily conserved phosphoinositide 3-kinase activity of inositol polyphosphate multikinase, which is localized to nuclei and unaffected by wortmannin. In yeast, this inositol lipid kinase activity physiologically regulates transcription.

Carbon monoxide neurotransmission activated by CK2 phosphorylation of heme oxygenase-2

Carbon monoxide (CO) is a putative gaseous neurotransmitter that lacks vesicular storage and must be synthesized rapidly following neuronal depolarization. We show that the biosynthetic enzyme for CO, heme oxygenase-2 (HO2), is activated during neuronal stimulation by phosphorylation by CK2 (formerly casein kinase 2). Phorbol ester treatment of hippocampal cultures results in the phosphorylation and activation of HO2 by CK2, implicating protein kinase C (PKC) in CK2 stimulation. Odorant treatment of olfactory receptor neurons augments HO2 phosphorylation and activity as well as cyclic guanosine monophosphate (cGMP) levels, with all of these effects selectively blocked by CK2 inhibitors. Likewise, CO-mediated nonadrenergic, noncholinergic (NANC) relaxation of the internal anal sphincter requires CK2 activity. Our findings provide a molecular mechanism for the rapid neuronal activation of CO biosynthesis, as required for a gaseous neurotransmitter.

Parturition dysfunction in obesity: time to target the pathobiology

Over a third of women of childbearing age in the United States are obese, and during pregnancy they are at increased risk for delayed labor onset and slow labor progress that often results in unplanned cesarean delivery. The biology behind this dysfunctional parturition is not well understood. Studies of obesity-induced changes in parturition physiology may facilitate approaches to optimize labor in obese women. In this review, we summarize known and proposed biologic effects of obesity on labor preparation, contraction/synchronization, and endurance, drawing on both clinical observation and experimental data. We present evidence from human and animal studies of interactions between obesity and parturition signaling in all elements of the birth process, including: delayed cervical ripening, prostaglandin insensitivity, amniotic membrane strengthening, decreased myometrial oxytocin receptor expression, decreased myocyte action potential initiation and contractility, decreased myocyte gap junction formation, and impaired myocyte neutralization of reactive oxygen species. We found convincing clinical data on the effect of obesity on labor initiation and successful delivery, but few studies on the underlying pathobiology. We suggest research opportunities and therapeutic interventions based on plausible biologic mechanisms.

UDP-glucuronate decarboxylase, a key enzyme in proteoglycan synthesis: cloning, characterization, and localization

UDP-glucuronate decarboxylase (UGD) catalyzes the formation of UDP-xylose from UDP-glucuronate. UDP-xylose is then used to initiate glycosaminoglycan biosynthesis on the core protein of proteoglycans. In a yeast two-hybrid screen with the protein kinase Akt (protein kinase B), we detected interactions with a novel sequence, which we cloned and expressed. The expressed protein displayed UGD activity but did not display the activities of homologous nucleotide sugar epimerases or dehydratases. We did not detect phosphorylation of UGD by Akt nor did we detect any influence of Akt on UGD activity. Effects of UGD on Akt kinase activity were also absent. Northern blot and Western blot analyses revealed the presence of UGD in multiple tissues and brain regions. Subcellular studies and histochemistry localized UGD protein to the perinuclear Golgi where xylosylation of proteoglycan core proteins is known to occur.

Alternatively spliced neuronal nitric oxide synthase mediates penile erection

A key role for nitric oxide (NO) in penile erection is well established, but the relative roles of the neuronal NO synthase (nNOS) versus endothelial forms of NOS are not clear. nNOS- and endothelial NOS-deficient mice maintain erectile function and reproductive capacity, questioning the importance of NO. Alternatively, residual NO produced by shorter transcripts in the nNOS(-/-) animals might suffice for normal physiologic function. We show that the beta splice variant of nNOS elicits normal erection despite a decrease in stimulus-response characteristics and a 5-fold increased sensitivity to the NOS inhibitor, l-NAME. Residual nNOSbeta generates only 10% of the normal NO level in vitro but produces citrulline and diaphorase staining reflecting in vivo NOS activity in pelvic ganglion nerves that is comparable to WT animals. Thus, alternatively spliced forms of nNOS are major mediators of penile erection and so may be targets for therapeutic intervention.

Sustained nitric oxide (NO)-releasing compound reverses dysregulated NO signal transduction in priapism

We evaluated the therapeutic potential of a sustained nitric oxide (NO)-releasing compound to correct the molecular hallmarks and pathophysiology of priapism, an important but poorly characterized erectile disorder. 1,5-Bis-(dihexyl-N-nitrosoamino)-2,4-dinitrobenzene (C6') and an inactive form of the compound [1,5-bis-(dihexylamino)-2,4-dinitrobenzene (C6)] were tested in neuronal cell cultures and penile lysates for NO release (Griess assay) and biological activity (cGMP production). The effect of local depot C6' or C6 was evaluated in mice with a priapic phenotype due to double neuronal and endothelial NO synthase deletion (dNOS(-/-)) or human sickle hemoglobin transgenic expression (Sickle). Changes in NO signaling molecules and reactive oxygen species (ROS) surrogates were assessed by Western blot. The physiological response after C6' treatment was assessed using an established model of electrically stimulated penile erection. C6' generated NO, increased cGMP, and dose dependently increased NO metabolites. C6' treatment reversed abnormalities in key penile erection signaling molecules, including phosphodiesterase type 5, phosphorylated endothelial nitric oxide synthase, and phosphorylated vasodilator-stimulated phosphoprotein. In Sickle mice, C6' also attenuated the increased ROS markers gp91(phox), 4-hydroxynonenal, and 3-nitrotyrosine. Finally, C6' corrected the excessive priapic erection response of dNOS(-/-) mice. Exogenous sustained NO release from C6' corrects pathological erectile signaling in mouse models of priapism and suggests novel approaches to human therapy.

Association between provider type and cesarean birth in healthy nulliparous laboring women: A retrospective cohort study

BACKGROUND

Term nulliparous women have the greatest variation across hospitals and providers in cesarean rates and therefore present an opportunity to improve quality through optimal care. We evaluated associations between provider type and mode of birth, including examination of intrapartum management in healthy, laboring nulliparous women.

METHODS

Retrospective cohort study using prospectively collected perinatal data from a United States academic medical center (2005-2012). The sample included healthy nulliparous women with spontaneous labor onset and term, singleton, vertex fetus managed by either obstetricians or certified nurse-midwives. Univariate and multivariate logistic regression was used to compare labor interventions and mode of birth by provider type.

RESULTS

A total of 1339 women received care by an obstetrician (n = 749) or nurse-midwife (n = 590). The cesarean rate was 13.4% (179/1339). Adjusting for maternal and pregnancy characteristics, care by obstetricians was associated with an increased risk of unplanned cesarean birth (adjusted odds ratio [aOR] 1.48 [95% confidence interval {CI} 1.04-2.12]) compared with care by midwives. Obstetricians more frequently used oxytocin augmentation (aOR 1.41 [95% CI 1.10-1.80]), neuraxial anesthesia (aOR 1.69 [95% CI 1.29-2.23]), and operative vaginal delivery with forceps or vacuum (aOR 2.79 [95% CI 1.75-4.44]). Adverse maternal or neonatal outcomes were not different by provider type across all modes of birth, but were more frequent in women with cesarean than vaginal births.

DISCUSSION

In low-risk nulliparous laboring women, care by obstetricians compared with nurse-midwives was associated with increased risk of labor interventions and operative birth. Changes in labor management or increased use of nurse-midwives could decrease the rate of a first cesarean in low-risk laboring women.

Seminal Fluid Metabolomic Markers of Oligozoospermic Infertility in Humans

Infertility affects 12–15% of couples worldwide, and male factors are the cause of nearly half of all cases. Studying seminal fluid composition could lead to additional diagnostic accuracy and a better understanding of the pathophysiology of male factor infertility. Metabolomics offers a new opportunity to evaluate biomarkers and better understand pathological mechanisms. The aim of the study was to identify new markers or therapeutic targets to improve outcomes in male factor or idiopathic infertility patients. Semen samples were obtained from 29 men with a normal spermogram test, and from 18 oligozoospermic men. Samples were processed and analyzed by Nuclear Magnetic Resonance spectroscopy and, subsequently, multivariate and univariate statistical analyses. Receiving Operator Curves (ROC) and Spearman correlations were also performed. An Orthogonal Partial Least Square Discriminant Analysis supervised multivariate model was devised to compare the groups. The levels of fructose, myo-inositol, aspartate and choline were altered. Moreover, Spearman Correlation associated fructose, aspartate and myo-inositol with the total amount of spermatozoa, total motile spermatozoa, % of immotility and % of “in situ” spermatozoic motility respectively. NMR-based metabolomics allowed the identification of a specific metabolic fingerprint of the seminal fluids of patients affected by oligozoospermia.

Use of a modified cluster sampling method to perform rapid needs assessment after Hurricane Andrew

STUDY OBJECTIVE

To rapidly obtain population-based estimates of needs in the early aftermath of Hurricane Andrew in South Florida.

METHODS

We used a modified cluster-sampling method (the Expanded Programme on Immunization [EPI] method) for three surveys. We selected a systematic sample of 30 quarter-mile square clusters for each survey and, beginning from a random start, interviewed members of seven consecutive occupied households in each cluster. Two surveys were of the most affected area (1990 population, 32,672) at three and ten days after the hurricane struck; one survey was of a less affected area (1990 population, 15,576) seven days after the hurricane struck.

MEASUREMENTS AND MAIN RESULTS

Results were available within 24 hours of beginning each survey. Initial findings emphasized the need for restoring utilities and sanitation and helped to focus medical relief on primary care and preventive services. The second survey of the most affected area showed improvement in the availability of food, water, electricity, and sanitation (P < or = .05). There was no evidence of disease outbreaks.

CONCLUSION

For the first time, the EPI method provided population-based information to guide and evaluate relief operations after a sudden-impact natural disaster. An improvement over previous approaches, the EPI method warrants further evaluation as a needs assessment tool in acute disasters.

Effects of resveratrol or estradiol on postexercise endothelial function in estrogen-deficient postmenopausal women

Regular exercise enhances endothelial function in older men, but not consistently in estrogen-deficient postmenopausal women. Estradiol treatment improves basal endothelial function and restores improvements in endothelial function (flow-mediated dilation, FMD) to aerobic exercise training in postmenopausal women; however, estradiol treatment is controversial. Resveratrol, an estrogen receptor ligand, enhances exercise training effects on cardiovascular function and nitric oxide (NO) release in animal models, but impairs exercise training effects in men. We conducted a randomized cross-over, double-blinded, placebo-controlled pilot study to determine whether acute (single dose) resveratrol (250-mg tablet) or estradiol (0.05 mg/day transdermal patch) treatment enhances FMD at rest and after a single bout of moderate-intensity aerobic exercise in healthy estrogen-deficient postmenopausal women (n = 15, 58.1 ± 3.2 yr). FMD was measured before and after (30, 60, and 120 min) a 40-min bout of moderate-intensity treadmill exercise (60-75% peak heart rate) under the respective conditions (separated by 1-2 wk). FMD was higher (P < 0.05) before exercise and at all post-exercise time points in the resveratrol and estradiol conditions compared to placebo. FMD was increased from baseline by 120 min postexercise in the estradiol condition (P < 0.001), but not resveratrol or PL conditions. Consistent with our previous findings, estradiol also enhances endothelial function in response to acute endurance exercise. Although resveratrol improved basal FMD, there was no apparent enhancement of FMD to acute exercise and, therefore, may not act as an estradiol mimetic.NEW & NOTEWORTHY The benefits of endurance exercise training on endothelial function are diminished in estrogen-deficient postmenopausal women, but estradiol treatment appears to restore improvements in endothelial function in this group. We show that basal endothelial function is enhanced with both acute estradiol and resveratrol treatments in estrogen-deficient postmenopausal women, but endothelial function is only enhanced following acute endurance exercise with estradiol treatment.

Metabolomics in Prenatal Medicine: A Review

Pregnancy is a complicated and insidious state with various aspects to consider, including the well-being of the mother and child. Developing better non-invasive tests that cover a broader range of disorders with lower false-positive rates is a fundamental necessity in the prenatal medicine field, and, in this sense, the application of metabolomics could be extremely useful. Metabolomics measures and analyses the products of cellular biochemistry. As a biomarker discovery tool, the integrated holistic approach of metabolomics can yield new diagnostic or therapeutic approaches. In this review, we identify and summarize prenatal metabolomics studies and identify themes and controversies. We conducted a comprehensive search of PubMed and Google Scholar for all publications through January 2020 using combinations of the following keywords: nuclear magnetic resonance, mass spectrometry, metabolic profiling, prenatal diagnosis, pregnancy, chromosomal or aneuploidy, pre-eclampsia, fetal growth restriction, pre-term labor, and congenital defect. Metabolite detection with high throughput systems aided by advanced bioinformatics and network analysis allowed for the identification of new potential prenatal biomarkers and therapeutic targets. We took into consideration the scientific papers issued between the years 2000-2020, thus observing that the larger number of them were mainly published in the last 10 years. Initial small metabolomics studies in perinatology suggest that previously unidentified biochemical pathways and predictive biomarkers may be clinically useful. Although the scientific community is considering metabolomics with increasing attention for the study of prenatal medicine as well, more in-depth studies would be useful in order to advance toward the clinic world as the obtained results appear to be still preliminary. Employing metabolomics approaches to understand fetal and perinatal pathophysiology requires further research with larger sample sizes and rigorous testing of pilot studies using various omics and traditional hypothesis-driven experimental approaches.

Gasotransmitters in pregnancy: from conception to uterine involution

Gasotransmitters are endogenous small gaseous messengers exemplified by nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S or sulfide). Gasotransmitters are implicated in myriad physiologic functions including many aspects of reproduction. Our objective was to comprehensively review basic mechanisms and functions of gasotransmitters during pregnancy from conception to uterine involution and highlight future research opportunities. We searched PubMed and Web of Science databases using combinations of keywords nitric oxide, carbon monoxide, sulfide, placenta, uterus, labor, and pregnancy. We included English language publications on human and animal studies from any date through August 2018 and retained basic and translational articles with relevant original findings. All gasotransmitters activate cGMP signaling. NO and sulfide also covalently modify target protein cysteines. Protein kinases and ion channels transduce gasotransmitter signals, and co-expressed gasotransmitters can be synergistic or antagonistic depending on cell type. Gasotransmitters influence tubal transit, placentation, cervical remodeling, and myometrial contractility. NO, CO, and sulfide dilate resistance vessels, suppress inflammation, and relax myometrium to promote uterine quiescence and normal placentation. Cervical remodeling and rupture of fetal membranes coincide with enhanced oxidation and altered gasotransmitter metabolism. Mechanisms mediating cellular and organismal changes in pregnancy due to gasotransmitters are largely unknown. Altered gasotransmitter signaling has been reported for preeclampsia, intrauterine growth restriction, premature rupture of membranes, and preterm labor. However, in most cases specific molecular changes are not yet characterized. Nonclassical signaling pathways and the crosstalk among gasotransmitters are emerging investigation topics.

FK506 neuroprotection after cavernous nerve injury is mediated by thioredoxin and glutathione redox systems

INTRODUCTION

Immunophilin ligands such as FK506 (FK) preserve erectile function (EF) following cavernous nerve injury (CNI), although the precise mechanisms are unclear. We examined whether the thioredoxin (Trx) and glutathione (GSH) redox systems mediate this effect after CNI.

AIM

To investigate the roles of Trx reductase 2 (TrxR2) and S-Nitrosoglutathione reductase (GSNOR) as antioxidative/nitrosative and antiapoptotic mediators of the neuroprotective effect of FK in the penis after CNI.

METHODS

Adult male rats, wild-type (WT) mice, and GSNOR deficient (GSNOR -/-) mice were divided into four groups: sham surgery (CN [cavernous nerves] exposure only) + vehicle; sham surgery + FK (5 mg/kg/day/rat or 2 mg/kg/day/mouse, for 2 days, subcutaneous); CNI + vehicle; and CNI + FK. At day 4 after injury, electrically stimulated changes in intracavernosal pressure (ICP) were measured. Penises were collected for Western blot analysis of TrxR2, GSNOR, and Bcl-2, and for immunolocalization of TrxR2 and GSNOR.

MAIN OUTCOME MEASURES

EF assessment represented by maximal ICP and total ICP in response to electrical stimulation. Evaluation of protein expression levels and distribution patterns of antioxidative/nitrosative and antiapoptotic factors in penile tissue.

RESULTS

EF decreased after CNI compared with sham surgery values in both rats (P < 0.01) and WT and GSNOR -/- mice (P < 0.05). FK treatment preserved EF after CNI compared with vehicle treatment in rats (P < 0.01) and WT mice (P < 0.05) but not in GSNOR -/- mice. In rats, GSNOR (P < 0.01) and Bcl-2 (P < 0.05) expressions were significantly decreased after CNI. FK treatment in CN-injured rats restored expression of GSNOR and upregulated TrxR2 (P < 0.001) and Bcl-2 (P < 0.001) expressions compared with vehicle treatment. Localizations of proteins in the penis were observed for TrxR2 (endothelium, smooth muscle) and for GSNOR (nerves, endothelium, smooth muscle).

CONCLUSIONS

The neuroprotective effect of FK in preserving EF after CNI involves antioxidative/nitrosative and antiapoptotic mechanisms mediated, to some extent, by Trx and GSH systems.

Na+-Leak Channel, Non-Selective (NALCN) Regulates Myometrial Excitability and Facilitates Successful Parturition

BACKGROUND/AIMS

Uterine contractility is controlled by electrical signals generated by myometrial smooth muscle cells. Because aberrant electrical signaling may cause inefficient uterine contractions and poor reproductive outcomes, there is great interest in defining the ion channels that regulate uterine excitability. In human myometrium, the Na+ leak channel, non-selective (NALCN) contributes to a gadolinium-sensitive, Na+-dependent leak current. The aim of this study was to determine the role of NALCN in regulating uterine excitability and examine its involvement in parturition.

METHODS

Wildtype C57BL/6J mice underwent timed-mating and NALCN uterine expression was measured at several time points across pregnancy including pregnancy days 7, 10, 14, 18 and 19. Sharp electrode current clamp was used to measure uterine excitability at these same time points. To determine NALCN's contribution to myometrial excitability and pregnancy outcomes, we created smooth-muscle-specific NALCN knockout mice by crossing NALCNfx/fx mice with myosin heavy chain Cre (MHCCreeGFP) mice. Parturition outcomes were assessed by observation via surveillance video recording cre control, flox control, smNALCN+/-, and smNALCN-/- mice. Myometrial excitability was compared between pregnancy day 19 flox controls and smNALCN-/- mice.

RESULTS

We found that in the mouse uterus, NALCN protein levels were high early in pregnancy, decreased in mid and late pregnancy, and then increased in labor and postpartum. Sharp electrode current clamp recordings of mouse longitudinal myometrial samples from pregnancy days 7, 10, 14, 18, and 19 revealed day-dependent increases in burst duration and interval and decreases in spike density. NALCN smooth muscle knockout mice had reduced myometrial excitability exemplified by shortened action potential bursts, and an increased rate of abnormal labor, including prolonged and dysfunctional labor.

CONCLUSIONS

Together, our findings demonstrate that the Na+ conducting channel NALCN contributes to the myometrial action potential waveform and is important for successful labor outcomes.

Increased activation of L-type voltage-dependent calcium channels is associated with glycine enhancement of N-methyl-D-aspartate-stimulated dopamine release in global cerebral ischemia/reperfusion

We investigated the relationships among N-methyl-D-aspartate, glycine, L-type voltage-dependent calcium channels, and [3H]dopamine release in a canine model of global cerebral ischemia/reperfusion. The binding of [3H]PN200-110 ([3H]isradipine) to L-type voltage-dependent calcium channels, that open as a consequence of N-methyl-D-aspartate-induced changes in membrane potential, was approximately doubled in striatal membranes prepared from ischemic animals relative to controls, and remained significantly elevated at 30 min and 2 h of reperfusion. These changes coincided temporally with changes in the ability of the voltage-sensitive calcium channel blocker nitrendipine to inhibit glycine enhancement of N-methyl-D-aspartate-stimulated [3H]dopamine release in striatal slices prepared from the same animals. Compared with nonischemic controls, N-methyl-D-aspartate-stimulated [3H]dopamine release was increased in ischemic animals and remained increased throughout reperfusion up to at least 24 h. Glycine enhanced N-methyl-D-aspartate-stimulated release in all treatment groups. The enhancement of N-methyl-D-aspartate-stimulated dopamine release by glycine was reduced by the inclusion of nitrendipine in striatal slices from ischemic and 30-min reperfused animals. These data suggest that glycine may facilitate opening of the voltage-dependent calcium channels activated by N-methyl-D-aspartate and that this facilitation is blocked by the antagonist nitrendipine.

Prevention and Management of Severe Obstetric Anal Sphincter Injuries (OASIs): a National Survey of Nurse- Midwives

INTRODUCTION AND HYPOTHESIS

There are no data on midwives' knowledge and management of obstetric anal sphincter injuries (OASIs) in the USA. We performed a cross-sectional national survey characterizing OASI practice by certified nurse midwives (CNMs), hypothesizing that few midwives personally repair OASIs and that there are gaps in CNM OASI training/education.

METHODS

We emailed a REDCap internet-based survey to 6909 American College of Nurse Midwives members (ACNM). We analyzed responses from active clinicians performing at least one delivery per month, asking about OASI risks, prevention, repair, and management. We summarized descriptive data then evaluated OASI knowledge by patient and provider characteristics.

RESULTS

We received 1070 (15.5%) completed surveys, and 832 (77.8%) met the inclusion/exclusion criteria. Participants were similar to ACNM membership. Respondents most frequently identified prior OASI (87%) and nutrition (71%) as antepartum OASI risk factors and, less frequently, nulliparity (36%) and race (22%). Identified intrapartum risks included forceps delivery (94%) and midline episiotomy (88%). When obstetric laceration is suspected, 13.6% of respondents perform a rectal examination routinely. Only 15% of participants personally perform OASI repair. Overall, participants matched 64% of evidence-based answers. OASI education/training courses were attended by 30% of respondents, and 44% knew of OASI protocols within their group/institution. Of all factors evaluated, the percent of evidence-based responses was only different for respondent education/CME and protocols.

CONCLUSIONS

Quality initiatives regarding OASI prevention and management may improve care. Our data suggest OASI training for midwives may improve delivery care in the US. Further studies of other obstetric providers are needed.

Perinatal Endotoxemia Induces Sustained Hepatic COX-2 Expression through an NFκB-Dependent Mechanism

BACKGROUND

Exposure to perinatal infection is associated with the multiple morbidities complicating preterm birth. How a relatively immature innate immune response contributes to this is unknown.

OBJECTIVE

We sought to determine if the perinatal innate immune response to endotoxemia induces a unique pattern of cyclooxygenase-2 (COX-2) expression via an NFκB-dependent mechanism.

METHODS

Hepatic and pulmonary COX-2 mRNA expression was assessed following perinatal (at embryonic days 15 and 19 and after birth) or adult endotoxemia. Hepatic NFκB activity was assessed by cytosolic inhibitory protein degradation and subunit nuclear translocation. Immunohistochemistry and isolated cell preparations determined hepatic macrophage COX-2 expression, and the effect of pharmacologic and genetic inhibition of NFκB activity was tested.

RESULTS

Perinatal endotoxemia induced sustained hepatic macrophage COX-2 expression and NFκB activity compared to in exposed adults. Isolated hepatic macrophages and immunohistochemistry demonstrated enriched LPS-induced COX-2 expression that was sensitive to pharmacologic and genetic approaches to attenuate NFκB activity. Finally, pharmacologic inhibition of endotoxemia-induced NFκB activity in neonatal mice prevented hepatic NFκB activity and attenuated COX-2 expression.

CONCLUSION

Our findings of sustained neonatal hepatic NFκB activity and COX-2 expression in response to endotoxemia support a robust perinatal innate immune response. This may represent a link between the innate immune response and the pathogenesis of diseases associated with preterm birth.

Sex-specific dysregulation of cysteine oxidation and the methionine and folate cycles in female cystathionine gamma-lyase null mice: a serendipitous model of the methylfolate trap

In addition to its role in the endogenous synthesis of cysteine, cystathionine gamma-lyase (CGL) is a major physiological source of the vasorelaxant hydrogen sulfide. Cgl null mice are potentially useful for studying the influence of this compound upon vascular tone and endothelial function. Here, we confirm a previous report that female Cgl null mice exhibit an approximate 45-fold increase in plasma total homocysteine compared to wild type controls. This level of homocysteine is approximately 3.5-fold higher than that observed in male Cgl null mice and is essentially equivalent to that observed in mouse models of cystathionine beta synthase deficient homocystinuria. Cgl null mice of both sexes exhibited decreased expression of methylenetetrahydrofolate reductase and cysteinesulfinate decarboxylase compared to WT controls. Female Cgl null mice exhibited a sex-specific induction of betaine homocysteine S-methyltransferase and methionine adenosyltransferase 1, alpha and a 70% decrease in methionine synthase expression accompanied by significantly decreased plasma methionine. Decreased plasma cysteine levels in female Cgl null mice were associated with sex-specific dysregulation of cysteine dioxygenase expression. Comparative histological assessment between cystathionine beta-synthase and Cgl null mice indicated that the therapeutic potential of cystathionine against liver injury merits possible further investigation. Collectively, our data demonstrates the importance of considering sex when investigating mouse models of inborn errors of metabolism and indicate that while female Cgl null mice are of questionable utility for studying the physiological role of hydrogen sulfide, they could serve as a useful model for studying the consequences of methionine synthase deficiency and the methylfolate trap.

Estrogen Regulates Local Cysteine Metabolism in Mouse Myometrium

Sulfur amino acid metabolism influences reproductive physiology, and transsulfuration in particular may be critical for normal cellular function. The sex hormone estrogen (E2) modulates gene expression and redox balance in some tissues by inducing the transsulfuration enzymes cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). The role of sex hormones in sulfur amino acid metabolism by uterine smooth muscle is not known. Here, we show that CBS and CSE proteins increase in the mouse myometrium during estrus and diestrus, respectively, suggesting that E2 reciprocally regulates myometrial CBS and CSE expression. In ovariectomized mice, exogenous E2 upregulates CBS and downregulates CSE levels. E2 promotes CBS mRNA and protein expression but attenuates CSE protein expression without affecting CSE mRNA. This pattern of E2-stimulated changes in transsulfuration enzyme expression is specific to the uterine smooth muscle. E2 does not change vaginal or cervical expression of CBS or CSE significantly, and E2 decreases expression of CSE in the liver without affecting CBS. E2 also downregulates myometrial cysteinesulfinic acid decarboxylase (CSAD) and decreases myometrial biochemical synthesis of the gaso-transmitter hydrogen sulfide (H2S). These findings suggest that myometrial sulfur amino acid metabolism may regulate uterine redox homeostasis, with implications for the source and metabolism of myometrial cysteine in high E2 states such as estrus and pregnancy.

Adiponectin links maternal metabolism to uterine contractility

Adiponectin is secreted by adipose tissue and promotes insulin sensitivity. Low circulating adiponectin is associated with increased risk for preterm labor, but the influence of adiponectin on uterine myometrial physiology is unknown. We hypothesized that adiponectin receptors (AdipoRs) decrease myometrial contractility via AMPK to promote uterine quiescence in pregnancy. Using quantitative RT-PCR, we found that nonpregnant or pregnant human and mouse myometrium express AdipoR1 and AdipoR2 mRNAs. We confirmed AdipoR2 protein expression in human and mouse myometrium, with increased abundance in late mouse pregnancy. Both recombinant adiponectin and a pharmacologic AdipoR agonist, AdipoRon, potently inhibited uterine myometrial strip contractions in physiologic organ bath. The relaxation was independent of contractile stimulus (oxytocin, KCl, U46619). AdipoR agonists increased AMPK phosphorylation in pregnant mouse myometrium, and the direct AMPK activator A769662 also relaxed myometrial strips. However, the AMPK inhibitor dorsomorphin (compound C) blocked AMPK phosphorylation but did not abolish relaxation with either AdipoRon or A769662. In summary, adiponectin inhibits myometrial contractility consistent with the possibility that it is a previously unrecognized link between maternal metabolism and pregnancy maintenance. We also identify a separate role for AMPK regulating myometrial contractions that may influence labor onset.-Vyas, V., Guerra, D. D., Bok, R., Powell, T., Jansson, T., Hurt, K. J. Adiponectin links maternal metabolism to uterine contractility.

The role of L-type voltage dependent calcium channels in stimulated [3H]norepinephrine release from canine hippocampal slices following global cerebral ischemia and reperfusion

The hippocampus is among those brain regions which are selectively vulnerable to ischemic damage. Hippocampal damage due to transient cerebral ischemia is mainly of the delayed, non-necrotic type which may arise after disruption or activation of specific cellular systems, including transmitter release through excitatory amino acid receptors. We investigated the contribution of L-type voltage dependent calcium channels (VDCCs) to glycine (GLY) potentiated N-methyl-D-aspartate (NMDA) receptor- and potassium-stimulated [3H]norepinephrine (NE) release in a canine model of global cerebral ischemia and reperfusion. Tissue was collected from four experimental groups: non-arrested controls (NA), global cerebral ischemia induced by 10 minute cardiac arrest (CA), and CA followed by 30 min or 24 hours reperfusion after restoration of spontaneous circulation. Brain slices prepared from all groups accumulated approximately equivalent amounts of [3H]NE. The sensitivity of [3H]NE release to stimulation by NMDA/GLY or elevated potassium was unchanged after ischemia and reperfusion. About 30% of release stimulated by the addition of 20 mM potassium was inhibited by the NMDA receptor-operated channel antagonist MK801 in all groups except CA in which only 4% of release was inhibited by MK801. The ability of 1 microM nitrendipine (NTP) to block stimulated release indicated that the contribution of the L-type VDCC to potassium or NMDA/GLY-stimulated release was significant only in NA and 24 hour reperfused animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Protein kinase A facilitates relaxation of mouse ileum via phosphorylation of neuronal nitric oxide synthase

BACKGROUND AND PURPOSE

The enteric neurotransmitter nitric oxide (NO) regulates gastrointestinal motility by relaxing smooth muscle. Pharmacological cAMP induction also relaxes gastrointestinal smooth muscle, but it is uncertain whether cAMP augments or suppresses enteric NO signalling. In other organ systems, cAMP can increase neuronal NO production by stimulating protein kinase A (PKA) to phosphorylate neuronal NOS (nNOS) Serine-1412 (S1412). We hypothesized that cAMP also increases nNOS S1412 phosphorylation by PKA in enteric neurons to augment nitrergic relaxation of mouse ileum.

EXPERIMENTAL APPROACH

We measured contractile force and nNOS S1412 phosphorylation in ileal rings suspended in an organ bath. We used forskolin to induce cAMP-dependent relaxation of wild type, nNOS^S1412A knock-in and nNOSα-null ileal rings in the presence or absence of PKA, protein kinase B (Akt) and NOS inhibitors.

KEY RESULTS

Forskolin stimulated phosphorylation of nNOS S1412 in mouse ileum. Forskolin relaxed nNOSα-null and nNOS^S1412A ileal rings less than wild-type ileal rings. PKA inhibition blocked forskolin-induced nNOS phosphorylation and attenuated relaxation of wild type but not nNOS^S1412A ileum. Akt inhibition did not alter nNOS phosphorylation with forskolin but did attenuate relaxation of wild type and nNOS^S1412A . NOS inhibition with L-NAME eliminated the effects of PKA and Akt inhibitors on relaxation.

CONCLUSION AND IMPLICATIONS

PKA phosphorylation of nNOS S1412 augments forskolin-induced nitrergic ileal relaxation. The relationship between cAMP/PKA and NO is therefore synergistic in enteric nitrergic neurons. Because NO regulates gut motility, selective modulation of enteric neuronal cAMP synthesis may be useful for the treatment of gastrointestinal motility disorders.