Single-Operator Left atrial appendage Occlusion utilizing Conscious sedation TEE, Lack of Outpatient pre-imaging, and Same-day Expedited discharge (SOLO-CLOSE): A comparison with conventional approach.

BACKGROUND: Left atrial appendage occlusion (LAAO) with WATCHMAN currently requires preprocedural imaging, general anesthesia, and inpatient overnight admission. We sought to facilitate simplification of LAAO. AIMS: We describe and compare SOLO-CLOSE (single-operator LAA occlusion utilizing conscious sedation TEE, lack of outpatient pre-imaging, and same-day expedited discharge) with the conventional approach (CA). METHODS: A single-center retrospective analysis of 163 patients undergoing LAAO between January 2017 and April 2022 was conducted. The SOLO-CLOSE protocol was enacted on December 1, 2020. Before this date, we utilized the CA. The primary efficacy endpoint was defined as successful LAAO with ≤5 mm peri-device leak at time of closure. The primary safety endpoint was the composite incidence of all-cause deaths, any cerebrovascular accident (CVA), device embolization, pericardial effusion, or major postprocedure bleeding within 7 days of the index procedure. Procedure times, 7-day readmission rates, and cost analytics were collected as well. RESULTS: Baseline characteristics were similar in both cohorts. Congestive heart failure (37.5% vs. 11.1%) and malignancy (28.8% vs. 12.5%) were higher in SOLO-CLOSE. Median CHA2D2SVASc score was 5 in both cohorts. The primary efficacy endpoint was met 100% in both cohorts. Primary safety endpoint was similar between cohorts (p = 0.078). Mean procedure time was 30 min shorter in SOLO-CLOSE (p < 0.01). Seven-day readmissions for SOLO-CLOSE was zero. After SOLO-CLOSE implementation, there was a 188% increase in positive contribution margin per case. CONCLUSIONS: The SOLO-CLOSE methodology offers similar efficacy and safety when compared to the CA, while improving clinical efficiency, reducing procedural times, and increasing economic benefit.

Death-associated protein kinase 3 regulates the myogenic reactivity of cerebral arteries.

NEW FINDINGS: What is the central question of this study? DAPK3 contributes to the Ca2+ -sensitization of vascular smooth muscle contraction: does this protein kinase participate in the myogenic response of cerebral arteries? What is the main finding and its importance? Small molecule inhibitors of DAPK3 effectively block the myogenic responses of cerebral arteries. HS38-dependent changes to vessel constriction occur independent of LC20 phosphorylation, and therefore DAPK3 appears to operate via the actin cytoskeleton. A role for DAPK3 in the myogenic response was not previously reported, and the results support a potential new therapeutic target in the cerebrovascular system. ABSTRACT: The vascular smooth muscle (VSM) of resistance blood vessels is a target of intrinsic autoregulatory responses to increased intraluminal pressure, the myogenic response. In the brain, the myogenic reactivity of cerebral arteries is critical to homeostatic blood flow regulation. Here we provide the first evidence to link the death-associated protein kinase 3 (DAPK3) to the myogenic response of rat and human cerebral arteries. DAPK3 is a Ser/Thr kinase involved in Ca2+ -sensitization mechanisms of smooth muscle contraction. Ex vivo administration of a specific DAPK3 inhibitor (i.e., HS38) could attenuate vessel constrictions invoked by serotonin as well as intraluminal pressure elevation. The HS38-dependent dilatation was not associated with any change in myosin light chain (LC20) phosphorylation. The results suggest that DAPK3 does not regulate Ca2+ sensitization pathways during the myogenic response of cerebral vessels but rather operates to control the actin cytoskeleton. A slow return of myogenic tone was observed during the sustained ex vivo exposure of cerebral arteries to HS38. Recovery of tone was associated with greater LC20 phosphorylation that suggests intrinsic signalling compensation in response to attenuation of DAPK3 activity. Additional experiments with VSM cells revealed HS38- and siDAPK-dependent effects on the actin cytoskeleton and focal adhesion kinase phosphorylation status. The translational importance of DAPK3 to the human cerebral vasculature was noted, with robust expression of the protein kinase and significant HS38-dependent attenuation of myogenic reactivity found for human pial vessels.

Smoothelin-like 1 knockout mice display sex-dependent alterations in blood flow and cardiac function.

Smoothelin-like 1 (SMTNL1) modulates the contractile performance of smooth muscle and thus has a key role in vascular homeostasis. Elevated vascular tone, recognized as a contributor to the development of progressive cardiac dysfunction, was previously found with SMTNL1 deletion. In this study, we assessed cardiac morphology and function of male and female, wild-type (Smtnl1+/+) and global SMTNL1 knockout (Smtnl1-/-) mice at 10 weeks of age. Gross dissection revealed distinct cardiac morphology only in males; Smtnl1-/- hearts were significantly smaller than Smtnl1+/+, but the left ventricle (LV) proportion of heart mass was greater. Male Smtnl1-/- mice also displayed increased ejection fraction and fractional shortening, as well as elevated aortic and pulmonary flow velocities. The impact of cardiac stress with pressure overload by transverse aortic constriction (TAC) was examined in male mice. With TAC banding, systolic function was preserved, but the LV filling pressure was selectively elevated due to relaxation impairment. Smtnl1-/- mice displayed higher early/passive filling velocity of LV/early mitral annulus velocity ratio (E/E' ratio) and myocardial performance index along with a prolonged isovolumetric relaxation time. Taken together, the findings support a novel, sex-dimorphic role for SMTNL1 in modulating cardiac structure and function of mice.

Cyclooxygenase inhibitors for treating preterm labour: What is the molecular evidence? 1.

Preterm birth (<37 weeks of gestation) significantly increases the risk of neonatal mortality and morbidity. As many as half of all preterm births occur following spontaneous preterm labour. Since in such cases there are no known reasons for the initiation of labour, treatment of preterm labour (tocolysis) has sought to stop labour contractions and delay delivery. Despite some success, the use of cyclooxygenase (COX) inhibitors is associated with maternal/fetal side effects, and possibly increased risk of preterm birth. Clinical use of these drugs predates the collection of molecular and biochemical evidence in vitro, examining the expression and activity of COX enzymes in pregnant uterine tissues with and without labour. Such evidence is important to the rationale that COX enzymes are, or are not, appropriate targets for the tocolysis. The current study systematically searched existing scientific evidence to address the hypothesis that COX expression/activity is increased with the onset of human labour, in an effort to determine whether there is a rationale for the use of COX inhibitors as tocolytics. Our review identified 44 studies, but determined that there is insufficient evidence to support or refute a role of COX-1/-2 in the onset of preterm labour that supports COX-targeted tocolysis.

Cellular and Ionic Mechanisms of Arterial Vasomotion.

Rhythmical contractility of blood vessels was first observed in bat wing veins by Jones (Philos Trans R Soc Lond 1852:142, 131-136), and subsequently described in arteries and arterioles of multiple vascular beds in several species. Despite an abundance of descriptive literature regarding the presence of vasomotion, to date we do not have an accurate picture of the cellular and ionic basis of these oscillations in tone, or the physiological relevance of the changes in pulsatile blood flow arising from vasomotion. This chapter reviews our current understanding of the cellular and ionic mechanisms underlying vasomotion in resistance arteries and arterioles. Focus is directed to the ion channels, changes in cytosolic Ca2+ concentration, and involvement of intercellular gap junctions in the development and synchronization of rhythmic changes in membrane potential and cytosolic Ca2+ concentration within the vessel wall that contribute to vasomotion. The physiological consequences of vasomotion are discussed with a focus on the cerebral vasculature, as recent advances show that rhythmic oscillations in cerebral arteriolar diameter appear to be entrained by cortical neural activity to increase the local supply of blood flow to active regions of the brain.

Airway epithelial compression promotes airway smooth muscle proliferation and contraction.

During acute bronchoconstriction, the airway epithelium becomes mechanically compressed, as airway smooth muscle contracts and the airway narrows. This mechanical compression activates airway epithelium to promote asthmatic airway remodeling. However, whether compressed airway epithelium can feed back on the cause of bronchoconstriction has remained an open question. Here we examine the potential for epithelial compression to augment proliferation and contraction of airway smooth muscle, and thus potentiate further bronchoconstriction and epithelial compression. Well-differentiated primary human bronchial epithelial (HBE) cells maintained in air-liquid interface culture were mechanically compressed to mimic the effect of bronchoconstriction. Primary human airway smooth muscle (HASM) cells were incubated with conditioned media collected from mechanically compressed HBE cells to examine the effect of epithelial-derived mediators on HASM cell proliferation using an EdU assay and HASM cell contraction using traction microscopy. An endothelin receptor antagonist, PD-145065, was employed to probe the role of HBE cell-derived endothelin-1 on the proliferation and contraction of HASM cells. Conditioned media from compressed HBE cells increased HASM cell proliferation, independent of the endothelin-1 signaling pathway. However, conditioned media from compressed HBE cells significantly increased HASM cell basal contraction and histamine-induced contraction, both of which depended on the endothelin-1 signaling pathway. Our data demonstrate that mechanical compression of bronchial epithelial cells contributes to proliferation and basal contraction of airway smooth muscle cells and that augmented contraction depends on epithelial cell-derived endothelin-1. By means of both airway smooth muscle remodeling and contractility, our findings suggest a causal role of epithelial compression on asthma pathogenesis.

Transient stretch induces cytoskeletal fluidization through the severing action of cofilin.

With every deep inspiration (DI) or sigh, the airway wall stretches, as do the airway smooth muscle cells in the airway wall. In response, the airway smooth muscle cell undergoes rapid stretch-induced cytoskeletal fluidization. As a molecular mechanism underlying the cytoskeletal fluidization response, we demonstrate a key role for the actin-severing protein cofilin. Using primary human airway smooth muscle cells, we simulated a DI by imposing a transient stretch of physiological magnitude and duration. We used traction microscopy to measure the resulting changes in contractile forces. After a transient stretch, cofilin-knockdown cells exhibited a 29 ± 5% decrease in contractile force compared with prestretch conditions. By contrast, control cells exhibited a 67 ± 6% decrease ( P < 0.05, knockdown vs. control). Consistent with these contractile force changes with transient stretch, actin filaments in cofilin-knockdown cells remained largely intact, whereas actin filaments in control cells were rapidly disrupted. Furthermore, in cofilin-knockdown cells, contractile force at baseline was higher and rate of remodeling poststretch was slower than in control cells. Additionally, the severing action of cofilin was restricted to the release phase of the transient stretch. We conclude that the actin-severing activity of cofilin is an important factor in stretch-induced cytoskeletal fluidization and may account for an appreciable part of the bronchodilatory effects of a DI.

The pro-inflammatory cytokine TNF-α inhibits lymphatic pumping via activation of the NF-κB-iNOS signaling pathway.

OBJECTIVE: Mesenteric lymphatic vessel pumping, important to propel lymph and immune cells from the intestinal interstitium to the mesenteric lymph nodes, is compromised during intestinal inflammation. The objective of this study was to test the hypothesis that the pro-inflammatory cytokine TNF-α, is a significant contributor to the inflammation-induced lymphatic contractile dysfunction, and to determine its mode of action. METHODS: Contractile parameters were obtained from isolated rat mesenteric lymphatic vessels mounted on a pressure myograph after 24-hours incubation with or without TNF-α. Various inhibitors were administered, and quantitative real-time PCR, Western blotting, and immunofluorescence confocal imaging were applied to characterize the mechanisms involved in TNF-α actions. RESULTS: Vessel contraction frequency was significantly decreased after TNF-α treatment and could be restored by selective inhibition of NF-кB, iNOS, guanylate cyclase, and ATP-sensitive K+ channels. We further demonstrated that NF-кB inhibition also suppressed the significant increase in iNOS mRNA observed in TNF-α-treated lymphatic vessels and that TNF-α treatment favored the nuclear translocation of the p65 NF-κB subunit. CONCLUSIONS: These findings suggest that TNF-α decreases mesenteric lymphatic contractility by activating the NF-κB-iNOS signaling pathway. This mechanism could contribute to the alteration of lymphatic pumping reported in intestinal inflammation.

Cytoskeletal reorganization evoked by Rho-associated kinase- and protein kinase C-catalyzed phosphorylation of cofilin and heat shock protein 27, respectively, contributes to myogenic constriction of rat cerebral arteries.

Our understanding of the molecular events contributing to myogenic control of diameter in cerebral resistance arteries in response to changes in intravascular pressure, a fundamental mechanism regulating blood flow to the brain, is incomplete. Myosin light chain kinase and phosphatase activities are known to be increased and decreased, respectively, to augment phosphorylation of the 20-kDa regulatory light chain subunits (LC20) of myosin II, which permits cross-bridge cycling and force development. Here, we assessed the contribution of dynamic reorganization of the actin cytoskeleton and thin filament regulation to the myogenic response and serotonin-evoked constriction of pressurized rat middle cerebral arteries. Arterial diameter and the levels of phosphorylated LC(20), calponin, caldesmon, cofilin, and HSP27, as well as G-actin content, were determined. A decline in G-actin content was observed following pressurization from 10 mm Hg to between 40 and 120 mm Hg and in three conditions in which myogenic or agonist-evoked constriction occurred in the absence of a detectable change in LC20 phosphorylation. No changes in thin filament protein phosphorylation were evident. Pressurization reduced G-actin content and elevated the levels of cofilin and HSP27 phosphorylation. Inhibitors of Rho-associated kinase and PKC prevented the decline in G-actin; reduced cofilin and HSP27 phosphoprotein content, respectively; and blocked the myogenic response. Furthermore, phosphorylation modulators of HSP27 and cofilin induced significant changes in arterial diameter and G-actin content of myogenically active arteries. Taken together, our findings suggest that dynamic reorganization of the cytoskeleton involving increased actin polymerization in response to Rho-associated kinase and PKC signaling contributes significantly to force generation in myogenic constriction of cerebral resistance arteries.

Contribution of kv7.4/kv7.5 heteromers to intrinsic and calcitonin gene-related peptide-induced cerebral reactivity.

OBJECTIVE: Middle cerebral artery (MCA) diameter is regulated by inherent myogenic activity and the effect of potent vasodilators such as calcitonin gene-related peptide (CGRP). Previous studies showed that MCAs express KCNQ1, 4, and 5 potassium channel genes, and the expression products (Kv7 channels) participate in the myogenic control of MCA diameter. The present study investigated the contribution of Kv7.4 and Kv7.5 isoforms to myogenic and CGRP regulation of MCA diameter and determined whether they were affected in hypertensive animals. APPROACH AND RESULTS: Isometric tension recordings performed on MCA from normotensive rats produced CGRP vasodilations that were inhibited by the pan-Kv7 channel blocker linopirdine (P<0.01) and after transfection of arteries with siRNA against KCNQ4 (P<0.01) but not KCNQ5. However, isobaric myography revealed that myogenic constriction in response to increases in intravascular pressure (20-80 mm Hg) was affected by both KCNQ4 and KCNQ5 siRNA. Proximity ligation assay signals were equally abundant for Kv7.4/Kv7.4 or Kv7.4/Kv7.5 antibody combinations but minimal for Kv7.5/Kv7.5 antibodies or Kv7.4/7.1 combinations. In contrast to systemic arteries, Kv7 function and Kv7.4 abundance in MCA were not altered in hypertensive rats. CONCLUSIONS: This study reveals, for the first time to our knowledge, that in cerebral arteries, Kv7.4 and Kv7.5 proteins exist predominantly as a functional heterotetramer, which regulates intrinsic myogenicity and vasodilation attributed to CGRP. Surprisingly, unlike systemic arteries, Kv7 activity in MCAs is not affected by the development of hypertension, and CGRP-mediated vasodilation is well maintained. As such, cerebrovascular Kv7 channels could be amenable for therapeutic targeting in conditions such as cerebral vasospasm.

Abnormal Rho-associated kinase activity contributes to the dysfunctional myogenic response of cerebral arteries in type 2 diabetes.

The structural and functional integrity of the brain, and therefore, cognition, are critically dependent on the appropriate control of blood flow within the cerebral circulation. Inadequate flow leads to ischemia, whereas excessive flow causes small vessel rupture and (or) blood-brain-barrier disruption. Cerebral blood flow is controlled through the interplay of several physiological mechanisms that regulate the contractile state of vascular smooth muscle cells (VSMCs) within the walls of cerebral resistance arteries and arterioles. The myogenic response of cerebral VSMCs is a key mechanism that is responsible for maintaining constant blood flow during variations in systemic pressure, i.e., flow autoregulation. Inappropriate myogenic control of cerebral blood flow is associated with, and prognostic of, neurological deterioration and poor outcome in patients with several conditions, including type 2 diabetes. Here, we review recent advances in our understanding of the role of inappropriate Rho-associated kinase activity as a cause of impaired myogenic regulation of cerebral arterial diameter in type 2 diabetes.

A pharmacologic activator of endothelial KCa channels enhances coronary flow in the hearts of type 2 diabetic rats.

Endothelial dysfunction is a common early pathogenic event in patients with type 2 diabetes (T2D) who exhibit cardiovascular disease. In the present study, we have examined the effect of SKA-31, a positive modulator of endothelial Ca(2+)-activated K(+) (KCa) channels, on total coronary flow in isolated hearts from Goto-Kakizaki rats, a non-obese model of T2D exhibiting metabolic syndrome. Total coronary flow and left ventricular developed pressure were monitored simultaneously in isolated, spontaneously beating Langendorff-perfused hearts. Acute administrations of bradykinin (BK) or adenosine (ADO) increased coronary flow, but responses were significantly blunted in diabetic hearts at 10-12 and 18-20weeks of age compared with age-matched Wistar controls, consistent with the presence of endothelial dysfunction. In contrast, SKA-31 dose-dependently (0.01-5µg) increased total coronary flow to comparable levels in both control and diabetic rat hearts at both ages. Flow responses to sodium nitroprusside were not different between control and diabetic hearts, suggesting normal arterial smooth muscle function. Importantly, exposure to a sub-threshold concentration of SKA-31 (i.e. 0.3µM) rescued the impaired BK and ADO-evoked vasodilatory responses in diabetic hearts. Endothelial KCa channel activators may thus help to preserve coronary flow in diabetic myocardium.

Overactive bladder mediated by accelerated Ca2+ influx mode of Na+/Ca2+ exchanger in smooth muscle.

The Na(+)/Ca(2+) exchanger (NCX) is thought to be a key molecule in the regulation of cytosolic Ca(2+) dynamics. The relative importance of the two Ca(2+) transport modes of NCX activity leading to Ca(2+) efflux (forward) and influx (reverse) in smooth muscle, however, remains unclear. Unexpectedly, spontaneous contractions of urinary bladder smooth muscle (UBSM) were enhanced in transgenic mice overexpressing NCX1.3 (NCX1.3(tg/tg)). The enhanced activity was attenuated by KB-R7943 or SN-6. Whole cell outward NCX current sensitive to KB-R7943 or Ni(2+) was readily detected in UBSM cells from NCX1.3(tg/tg) but not wild-type mice. Spontaneous Ca(2+) transients in myocytes of NCX1.3(tg/tg) were larger and frequently resulted in propagating events and global elevations in cytosolic Ca(2+) concentration. Significantly, NCX1.3(tg/tg) mice exhibited a pattern of more frequent urination of smaller volumes and this phenotype was reversed by oral administration of KB-R7943. On the other hand, KB-R7943 did not improve it in KB-R7943-insensitive (G833C-)NCX1.3(tg/tg) mice. We conclude that NCX1.3 overexpression is associated with abnormal urination owing to enhanced Ca(2+) influx via reverse mode NCX leading to prolonged, propagating spontaneous Ca(2+) release events and a potentiation of spontaneous UBSM contraction. These findings suggest the possibility that NCX is a candidate molecular target for overactive bladder therapy.

Ca2+ sensitization due to myosin light chain phosphatase inhibition and cytoskeletal reorganization in the myogenic response of skeletal muscle resistance arteries.

Abstract The myogenic response of resistance arteries to intravascular pressure elevation is a fundamental physiological mechanism of crucial importance for blood pressure regulation and organ-specific control of blood flow. The importance of Ca(2+) entry via voltage-gated Ca(2+) channels leading to phosphorylation of the 20 kDa myosin regulatory light chains (LC20) in the myogenic response is well established. Recent studies, however, have suggested a role for Ca(2+) sensitization via activation of the RhoA/Rho-associated kinase (ROK) pathway in the myogenic response. The possibility that enhanced actin polymerization is also involved in myogenic vasoconstriction has been suggested. Here, we have used pressurized resistance arteries from rat gracilis and cremaster skeletal muscles to assess the contribution to myogenic constriction of Ca(2+) sensitization due to: (1) phosphorylation of the myosin targeting subunit of myosin light chain phosphatase (MYPT1) by ROK; (2) phosphorylation of the 17 kDa protein kinase C (PKC)-potentiated protein phosphatase 1 inhibitor protein (CPI-17) by PKC; and (3) dynamic reorganization of the actin cytoskeleton evoked by ROK and PKC. Arterial diameter, MYPT1, CPI-17 and LC20 phosphorylation, and G-actin content were determined at varied intraluminal pressures ± H1152, GF109203X or latrunculin B to suppress ROK, PKC and actin polymerization, respectively. The myogenic response was associated with an increase in MYPT1 and LC20 phosphorylation that was blocked by H1152. No change in phospho-CPI-17 content was detected although the PKC inhibitor, GF109203X, suppressed myogenic constriction. Basal LC20 phosphorylation at 10 mmHg was high at ∼40%, increased to a maximal level of ∼55% at 80 mmHg, and exhibited no additional change on further pressurization to 120 and 140 mmHg. Myogenic constriction at 80 mmHg was associated with a decline in G-actin content by ∼65% that was blocked by inhibition of ROK or PKC. Taken together, our findings indicate that two mechanisms of Ca(2+) sensitization (ROK-mediated phosphorylation of MYPT1-T855 with augmentation of LC20 phosphorylation, and a ROK- and PKC-evoked increase in actin polymerization) contribute to force generation in the myogenic response of skeletal muscle arterioles.

Amniotic fluid embolism-induced cardiopulmonary collapse successfully treated with combination VA-ECMO and Impella CP.

Amniotic fluid embolism (AFE) is a rare but potentially fatal complication of pregnancy. Prompt and aggressive resuscitative strategies are crucial in promoting survivability. We present a case of AFE resulting in cardiopulmonary collapse and subsequent cardiac arrest where we were able to safely deliver the baby and resuscitate the mother with veno-arterial extracorporeal membrane oxygenation and Impella CP-a novel combination known as ECPELLA. We discuss the implications of this approach as a more efficacious strategy in resuscitating AFE-induced cardiogenic shock and arrest.

Severe aortic insufficiency-induced cardiogenic shock treated with left atrial VA-ECMO and emergent valve-in-valve TAVR.

Conventional venoarterial extracorporeal membrane oxygenation (VA-ECMO) places a functional afterload burden on the left ventricle. In the setting of acute severe aortic insufficiency-induced cardiogenic shock, the utility of VA-ECMO in combination with a failing valve may result in catastrophic haemodynamic consequences. This challenge is compounded when the culprit is a failing surgical bioprosthetic valve. We present a case of severe rapid-onset bioprosthetic aortic insufficiency-induced cardiogenic shock successfully resuscitated with left atrial VA-ECMO promptly followed by emergent percutaneous valve-in-valve transaortic valve replacement. We discuss the logistics, implications, and associated haemodynamic manifestations in utilizing this strategy for such disease processes.

Prenatal exposure to a low dose of BPS causes sex-dependent alterations to vascular endothelial function in adult offspring.

Background: Bisphenol S (BPS) is among the most commonly used substitutes for Bisphenol A (BPA), an endocrine disrupting chemical used as a plasticizer in the manufacture of polycarbonate plastics and epoxy resins. Bisphenols interfere with estrogen receptor (ER) signaling, which modulates vascular function through stimulation of nitric oxide (NO) production via endothelial nitric oxide synthase (eNOS). BPS can cross into the placenta and accumulates in the fetal compartment to a greater extent than BPA, potentially interfering with key developmental events. Little is known regarding the developmental impact of exposure to BPA substitutes, particularly with respect to the vasculature. Objective: To determine if prenatal BPS exposure influences vascular health in adulthood. Methods: At the time of mating, female C57BL/6 dams were administered BPS (250 nM) or vehicle control in the drinking water, and exposure continued during lactation. At 12-week of age, mesenteric arteries were excised from male and female offspring and assessed for responses to an endothelium-dependent (acetylcholine, ACh) and endothelium-independent (sodium nitroprusside, SNP) vasodilator. Endothelium-dependent dilation was measured in the presence or absence of L-NAME, an eNOS inhibitor. To further explore the role of NO and ER signaling, wire myography was used to assess ACh responses in aortic rings after acute exposure to BPS in the presence or absence of L-NAME or an ER antagonist. Results: Increased ACh dilation and increased sensitivity to Phe were observed in microvessels from BPS-exposed females, while no changes were observed in male offspring. Differences in ACh-induced dilation between control or BPS-exposed females were eliminated with L-NAME. Increased dilatory responses to ACh after acute BPS exposure were observed in aortic rings from female mice only, and differences were eliminated with inhibition of eNOS or inhibition of ER. Conclusion: Prenatal BPS exposure leads to persistent changes in endothelium-dependent vascular function in a sex-specific manner that appears to be modulated by interaction of BPS with ER signaling.

Rho-associated kinase plays a role in rabbit urethral smooth muscle contraction, but not via enhanced myosin light chain phosphorylation.

The involvement of Rho-associated kinase (ROK) in activation of rabbit urethral smooth muscle contraction was investigated by examining the effects of two structurally distinct inhibitors of ROK, Y27632 and H1152, on the contractile response to electric field stimulation, membrane depolarization with KCl, and α1-adrenoceptor stimulation with phenylephrine. Both compounds inhibited contractions elicited by all three stimuli. The protein kinase C inhibitor GF109203X, on the other hand, had no effect. Urethral smooth muscle strips were analyzed for phosphorylation of three potential direct or indirect substrates of ROK: 1) myosin regulatory light chains (LC20) at S19, 2) the myosin-targeting subunit of myosin light chain phosphatase (MYPT1) at T697 and T855, and 3) cofilin at S3. The following results were obtained: 1) under resting tension, LC20 was phosphorylated to 0.65±0.02 mol Pi/mol LC20 (n=21) at S19; 2) LC20 phosphorylation did not change in response to KCl or phenylephrine; 3) ROK inhibition had no effect on LC20 phosphorylation in the absence or presence of contractile stimuli; 4) under resting conditions, MYPT1 was partially phosphorylated at T697 and T855 and cofilin at S3; 5) phosphorylation of MYPT1 and cofilin was unaffected by KCl or phenylephrine; and 6) KCl- and phenylephrine-induced contraction-relaxation cycles did not correlate with actin polymerization-depolymerization. We conclude that ROK plays an important role in urethral smooth muscle contraction, but not via inhibition of MLCP or polymerization of actin.

Role of myosin light chain kinase and myosin light chain phosphatase in the resistance arterial myogenic response to intravascular pressure.

The intrinsic ability of vascular smooth muscle cells (VSMCs) within arterial resistance vessels to respectively contract and relax in response to elevation and reduction of intravascular pressure is essential for appropriate blood flow autoregulation. This fundamental mechanism, referred to as the myogenic response, is dependent on apposite control of myosin regulatory light chain (LC(20)) phosphorylation, a prerequisite for force generation, through the coordinated activity of myosin light chain kinase (MLCK) and myosin light chain phosphatase (MLCP). Here, we highlight the molecular basis of the smooth muscle contractile mechanism and review the regulatory pathways demonstrated to participate in the control of LC(20) phosphorylation in the myogenic response, with a focus on the Ca(2+)-dependent and Rho-associated kinase (ROK)-mediated regulation of MLCK and MLCP, respectively.

Antioxidant micronutrient impact on hearing disorders: concept, rationale, and evidence.

PURPOSE: Although auditory disorders are complex conditions, device-related modalities dominate current treatment. However, dysfunction from the central cortex to the inner ear apparatus is increasingly thought to be related to biochemical pathway abnormalities and to free radical-induced oxidative damage and chronic inflammation. Therefore, considering appropriate biologic therapy as an adjunct to standard care against these damaging factors may provide rational expansion of treatment options for otolaryngologists and audiologists. METHODS: This review outlines the biologic concepts related to some auditory and vestibular conditions and details the current rationale for utilizing antioxidants for a spectrum of hearing disorders. The strategy is based on the authors' collective experience in antioxidant science and supported with published research, pilot animal data and preliminary clinical observations. RESULTS: A comprehensive micronutrient approach was developed to exploit these pathways, and demonstrated safety and efficacy against oxidative damage and inflammation and clinically relevant neuroprotection. Cooperative research with Department of Defense institutions used prospective, randomized designs to show (1) reduction in oxidative damage measured in plasma and urine over six months, (2) protection against oxidative damage during 12 weeks of intense military training, (3) protection against inflammation after total body blast exposure (rodents), (4) strong neuroprotection against chemically-induced Parkinson's disease (rodents), (5) nerve VIII function improvement after concussive head injury in military personnel, and (6) tinnitus improvement in majority of patients after 90-day evaluation. CONCLUSION: This systematic review of biologic strategies against hearing disorders combined with new animal and human observations may provide a rational basis for expanding current practice paradigms.