Smooth Muscle Constriction Research Articles

Salidroside ameliorates hypoxic pulmonary hypertension by regulating the two-pore domain potassium TASK-1 channel

BackgroundHypoxic pulmonary vasoconstriction (HPV) is a reflex constriction of vascular smooth muscle. This study aims to investigate the role of Salidroside (Sal) in pulmonary arterial dilatation and the potential mechanism of Sal regulating hypoxic pulmonary hypertension in vitro and in vivo. MethodsA rat model of hypoxic pulmonary hypertension (HPH) was constructed using hypoxic chamber. The effect of Sal on HPH were evaluated using vascular ring, whole cell patch-clamp, WGA staining, HE staining, and Sirius Scarlet staining assays. ResultsSal treatment alleviated the injury of acute hypoxia on pulmonary circulation in SD rats. Meanwhile, Sal treatment reduced the pulmonary vascular tone of acute hypoxia in a concentration-dependent manner, which was involved in the TWIK-related acid-sensitive potassium channel 1 (TASK-1) mediating diastolic effect. We found that Sal treatment significantly increased the TASK-1 current of pulmonary artery smooth muscle cells (PASMCs) in a concentration-dependent manner, as well as reversed the inhibitory effect of acute hypoxia on the TASK-1 current. Moreover, Sal treatment improved the TASK-1 current density, suppressed the proliferation, and enhanced the apoptosis of PASMCs in SD rats under continuous hypoxic condition. In addition, we found that the electrophysiological remodeling and pulmonary vascular remodeling of PASMCs were improved by the treatment of Sal through the regulation of TASK-1 channel. ConclusionsSal could alleviate HPH by restoring the function of TASK-1 channel, which may provide a novel method for the treatment of HPH.

Cerebral Artery Overexpression of the NMUR1 Gene Is Associated with Moyamoya Disease: A Weighted Gene Co-Expression Network Analysis

Introduction: This study aimed to elucidate mechanisms underlying moyamoya disease (MMD) pathogenesis and to identify potential novel biomarkers. We utilized gene co-expression networks to identify hub genes associated with the disease. Methods: Twenty-one middle cerebral artery (MCA) samples from MMD patients and 11 MCA control samples were obtained from the Gene Expression Omnibus (GEO) dataset, GSE189993. To discover functional pathways and potential biomarkers, weighted gene co-expression network analysis (WGCNA) was employed. The hub genes identified were re-assessed through differential gene expression analysis (DGEA) via DESeq2 for further reliability verification. Additional 4 samples from the superficial temporal arteries (STAs) from MMD patients were obtained from GSE141025, and a subgroup analysis stratified by arterial type (MCA vs. STA) DGEA was performed to assess if the hub genes associated with MMD are expressed significantly greater on the affected arteries compared to healthy ones in MMD. Results: WGCNA revealed a predominant module encompassing 139 hub genes, predominantly associated with the neuroactive ligand-receptor interaction (NLRI) pathway. Of those, 17 genes were validated as significantly differentially expressed. Neuromedin U receptor 1 (NMUR1) and thyrotropin-releasing hormone were 2 out of the 17 hub genes involved in the NLRI pathway (log fold change [logFC]: 1.150, p = 0.00028; logFC: 1.146, p = 0.00115, respectively). MMD-only subgroup analysis stratified by location showed that NMUR1 is significantly overexpressed in the MCA compared to the STA (logFC: 1.962; p = 0.00053) which further suggests its possible localized involvement in the progressive stenosis seen in the cerebral arteries in MMD. Conclusion: This is the first study to have performed WGCNA on samples directly affected by MMD. NMUR1 expression is well known to induce localized arterial smooth muscle constriction and, recently, type 2 inflammation which can predispose to arterial stenosis potentially advancing the symptoms and progression of MMD. Further validation and functional studies are necessary to understand the precise role of NMUR1 upregulation in MMD and its potential implications.

SNPs in FAM13A and IL2RB genes are associated with FeNO in adult subjects with asthma

Nitric oxide has different roles in asthma as both an endogenous modulator of airway function and a pro-inflammatory mediator. Fractional exhaled nitric oxide (FeNO) is a reliable, quantitative, non-invasive, simple, and safe biomarker for assessing airways inflammation in asthma. Previous genome-wide and genetic association studies have shown that different genes and single nucleotide polymorphisms (SNPs) are linked to FeNO. We aimed at identifying SNPs in candidate genes or gene regions that are associated with FeNO in asthma. We evaluated 264 asthma cases (median age 42.8 years, female 47.7%) who had been identified in the general adult population within the Gene Environment Interactions in Respiratory Diseases survey in Verona (Italy; 2008–2010). Two hundred and twenty-one tag-SNPs, which are representative of 50 candidate genes, were genotyped by a custom GoldenGate Genotyping Assay. A two-step association analysis was performed without assuming an a priori genetic model: step (1) a machine learning technique [gradient boosting machine (GBM)] was used to select the 15 SNPs with the highest variable importance measure; step (2) the GBM-selected SNPs were jointly tested in a linear regression model with natural log-transformed FeNO as the normally distributed outcome and with age, sex, and the SNPs as covariates. We replicated our results within an independent sample of 296 patients from the European Community Respiratory Health Survey III. We found that SNP rs987314 in family with sequence similarity 13 member A (FAM13A) and SNP rs3218258 in interleukin 2 receptor subunit beta (IL2RB) gene regions are significantly associated with FeNO in adult subjects with asthma. These genes are involved in different mechanisms that affect smooth muscle constriction and endothelial barrier function responses (FAM13A), or in immune response processes (IL2RB). Our findings contribute to the current knowledge on FeNO in asthma by identifying two novel SNPs associated with this biomarker of airways inflammation.

Gβγ subunit signalling underlies neuropeptide Y-stimulated vasoconstriction in rat mesenteric and coronary arteries.

Raised serum concentrations of the sympathetic co-transmitter neuropeptide Y (NPY) are linked to cardiovascular diseases. However, the signalling mechanism for vascular smooth muscle (VSM) constriction to NPY is poorly understood. Therefore, the present study investigated the mechanisms of NPY-induced vasoconstriction in rat small mesenteric (RMA) and coronary (RCA) arteries. Third-order mesenteric or intra-septal arteries from male Wistar rats were assessed in wire myographs for isometric tension, VSM membrane potential and VSM intracellular Ca2+ events. NPY stimulated concentration-dependent vasoconstriction in both RMA and RCA, which was augmented by blocking NO synthase or endothelial denudation in RMA. NPY-mediated vasoconstriction was blocked by the selective Y1 receptor antagonist BIBO 3304 and Y1 receptor protein expression was detected in both the VSM and endothelial cells in RMA and RCA. The selective Gβγ subunit inhibitor gallein and the PLC inhibitor U-73122 attenuated NPY-induced vasoconstriction. Signalling via the Gβγ-PLC pathway stimulated VSM Ca2+ waves and whole-field synchronised Ca2+ flashes in RMA and increased the frequency of Ca2+ flashes in myogenically active RCA. Furthermore, in RMA, the Gβγ pathway linked NPY to VSM depolarization and generation of action potential-like spikes associated with intense vasoconstriction. This depolarization activated L-type voltage-gated Ca2+ channels, as nifedipine abolished NPY-mediated vasoconstriction. These data suggest that the Gβγ subunit, which dissociates upon Y1 receptor activation, initiates VSM membrane depolarization and Ca2+ mobilisation to cause vasoconstriction. This model may help explain the development of microvascular vasospasm during raised sympathetic nerve activity.

Pharmacological Studies on the Ca2+ Influx Pathways in Platelet-Activating Factor (PAF)-Induced Mouse Urinary Bladder Smooth Muscle Contraction.

Platelet-activating factor (PAF) not only acts as a mediator of platelet aggregation, inflammation, and allergy responses but also as a constrictor of various smooth muscle (SM) tissues, including gastrointestinal, tracheal/bronchial, and pregnancy uterine SMs. Previously, we reported that PAF induces basal tension increase (BTI) and oscillatory contraction (OC) in mouse urinary bladder SM (UBSM). In this study, we examined the Ca2+ influx pathways involved in PAF-induced BTI and OC in the mouse UBSM. PAF (10-6 M) induced BTI and OC in mouse UBSM. However, the PAF-induced BTI and OC were completely suppressed by extracellular Ca2+ removal. PAF-induced BTI and OC frequencies were markedly suppressed by voltage-dependent Ca2+ channel (VDCC) inhibitors (verapamil (10-5 M), diltiazem (10-5 M), and nifedipine (10-7 M)). However, these VDCC inhibitors had a minor effect on the PAF-induced OC amplitude. The PAF-induced OC amplitude in the presence of verapamil (10-5 M) was strongly suppressed by SKF-96365 (3 × 10-5 M), an inhibitor of receptor-operated Ca2+ channel (ROCC) and store-operated Ca2+ channel (SOCC), but not by LOE-908 (3 × 10-5 M) (an inhibitor of ROCC). Overall, PAF-induced BTI and OC in mouse UBSM depend on Ca2+ influx and the main Ca2+ influx pathways in PAF-induced BTI and OC may be VDCC and SOCC. Of note, VDCC may be involved in PAF-induced BTI and OC frequency, and SOCC might be involved in PAF-induced OC amplitude.

Association between spectral analysis of heart rate variability and pulmonary function tests in bronchial asthma patients.

The parasympathetic vagus nerve supplies the heart and lung. The Parasympathetic activity modifies the heart rate and force of contraction in the heart and Airway bronchial smooth muscle constriction and hypersecretion of mucus in the lungs. There is a link between these two components. Hence this study is designed to find the association between Spectral analysis of heart rate variability and pulmonary function tests in bronchial asthma patients. In this study, 30 asthmatic patients were recruited from the respiratory medicine outpatient department and 30 healthy volunteers were included. Pulmonary function tests and heart rate variability was recorded in the physiology department. The pulmonary function parameters were found significantly reduced in the asthmatic patient and it shows obstructive lung diseases. Heart rate variability parameters were found a statistically significantly decreased mean HR, VLF ms2, and LF ms2 in the asthmatic patients when compared to controls. HF ms2 was found significantly increased in the asthmatic patient. These HF ms2 were increased to represent parasympathetic hyperactivity. This study concluded there is parasympathetic dominance in asthmatic patients. The parasympathetic activity might be one of the reasons for increases the airway bronchoconstriction and hypersecretion of mucus. There is a negative correlation was found between FEV1 value and HF ms2. A decrease in the FEV1 value leads to an increase in HF ms2.

Cysteinyl leukotriene receptor 1 is dispensable for osteoclast differentiation and bone resorption.

Cysteinyl leukotriene receptor 1 (CysLTR1) is a G protein-coupled receptor for the inflammatory lipid mediators cysteinyl leukotrienes, which are involved in smooth muscle constriction, vascular permeability, and macrophage chemokine release. The Cysltr1 gene encoding CysLTR1 is expressed in the macrophage lineage, including osteoclasts, and the CysLTR1 antagonist Montelukast has been shown to suppress the formation of osteoclasts. However, it currently remains unclear whether CysLTR1 is involved in osteoclast differentiation and bone loss. Therefore, to clarify the role of CysLTR1 in osteoclastogenesis and pathological bone loss, we herein generated CysLTR1 loss-of-function mutant mice by disrupting the cysltr1 gene using the CRISPR-Cas9 system. These mutant mice had a frameshift mutation resulting in a premature stop codon (Cysltr1 KO) or an in-frame mutation causing the deletion of the first extracellular loop (Cysltr1Δ105). Bone marrow macrophages (BMM) from these mutant mice lost the intracellular flux of calcium in response to leukotriene D4, indicating that these mutants completely lost the activity of CysLTR1 without triggering genetic compensation. However, disruption of the Cysltr1 gene did not suppress the formation of osteoclasts from BMM in vitro. We also demonstrated that the CysLTR1 antagonist Montelukast suppressed the formation of osteoclasts without functional CysLTR1. On the other hand, disruption of the Cysltr1 gene partially suppressed the formation of osteoclasts stimulated by leukotriene D4 and did not inhibit that by glutathione, functioning as a substrate in the synthesis of cysteinyl leukotrienes. Disruption of the Cysltr1 gene did not affect ovariectomy-induced osteoporosis or lipopolysaccharide-induced bone resorption. Collectively, these results suggest that the CysLT-CysLTR1 axis is dispensable for osteoclast differentiation in vitro and pathological bone loss, while the leukotriene D4-CysTR1 axis is sufficient to stimulate osteoclast formation. We concluded that the effects of glutathione and Montelukast on osteoclast formation were independent of CysLTR1.

Use of β2-agonists for viral bronchiolitis

A 9-month-old baby presented to my rural emergency department with 2 days of cough and congestion and 1 day of breathing difficulties in the month of February. An auscultation examination of the lungs indicated there were scattered, faint wheezes and coarse sounds. Based on the baby’s age, symptomatology, and the winter season, the likely diagnosis was bronchiolitis. Are inhaled β2-agonists an appropriate treatment for this patient?The use of inhaled β2-agonists in children younger than 2 years of age with bronchiolitis is not indicated. Wheezing is most commonly part of the diagnosis of bronchiolitis, a lower respiratory viral infection in young children. Unlike with asthma, smooth muscle constriction in the lungs is not a symptom of bronchiolitis. Treatment of bronchiolitis requires supportive care, but pharmaceutical interventions such as β2-agonists, steroids, and antibiotics have not been shown to decrease length of illness, illness severity, or hospitalization rates. There may be a subgroup of infants with bronchiolitis who respond to β2-agonists treatment; however, this group has not been fully identified in the literature to date.

Light-Mediated Inhibition of Colonic Smooth Muscle Constriction and Colonic Motility via Opsin 3.

Opsin photoreceptors outside of the central nervous system have been shown to mediate smooth muscle photorelaxation in several organs. We hypothesized that opsin receptor activation in the colon would have a similar effect and influence colonic motility. We detected Opsin 3 (OPN3) protein expression in the colonic wall and demonstrated that OPN3 was present in enteric neurons in the muscularis propria of the murine colon. Precontracted murine colon segments demonstrated blue light (BL) -mediated relaxation ex vivo. This photorelaxation was wavelength specific and was increased with the administration of the chromophore 9-cis retinal and a G protein receptor kinase 2 (GRK2) inhibitor. Light-mediated relaxation of the colon was not inhibited by L-NAME or tetrodotoxin (TTX). Furthermore, BL exposure in the presence of 9-cis retinal decreased the frequency of colonic migrating motor complexes (CMMC) in spontaneously contracting mouse colons ex vivo. These results demonstrate for the first time a receptor-mediated photorelaxation of colonic smooth muscle and implicate opsins as possible new targets in the treatment of spasmodic gastrointestinal dysmotility.

Protective effects of Surfacen® in allergen-induced asthma mice model

Airway obstruction with increased airway resistance in asthma, commonly caused by smooth muscle constriction, mucosal edema and fluid secretion into the airway lumen, may partly be due to a poor function of pulmonary surfactant. Surfacen®, a clinical pulmonary surfactant, has anti-inflammatory action, but its effect on asthma has not been studied. This work aimed to evaluate the effect of Surfacen® in a murine allergen-induced acute asthma model, using house dust mite allergens. In a therapeutic experimental setting, mice were first sensitized by being administered with two doses (sc) of Dermatophagoides siboney allergen in aluminum hydroxide followed by one intranasal administration of the allergen. Then, sensitized mice were administered with aerosol of hypertonic 3% NaCl, Salbutamol 0.15 mg/kg, or Surfacen® 16 mg in a whole-body chamber on days 22, 23, and 24. Further, mice were subjected to aerosol allergen challenge on day 25. Surfacen® showed bronchial dilation and inhibition of Th2 inflammation (lower levels of IL-5 and IL-13 in broncoalveolar lavage) which increased IFN-γ and unchanged IL-10 in BAL. Moreover, Sufacen® administration was associated with a marked inhibition of the serum specific IgE burst upon allergen exposure, as well as, IgG2a antibody increase, suggesting potential anti-allergy effects with inclination towards Th1. These results support also the effectiveness of the aerosol administration method to deliver the drug into lungs. Surfacen® induced a favorable pharmacological effect, with a bronchodilator outcome comparable to Salbutamol, consistent with its action as a lung surfactant, and with an advantageous anti-inflammatory and anti-allergic immunomodulatory effect.

Aging-Induced Impairment of Vascular Function: Mitochondrial Redox Contributions and Physiological/Clinical Implications.

Significance: The vasculature responds to the respiratory needs of tissue by modulating luminal diameter through smooth muscle constriction or relaxation. Coronary perfusion, diastolic function, and coronary flow reserve are drastically reduced with aging. This loss of blood flow contributes to and exacerbates pathological processes such as angina pectoris, atherosclerosis, and coronary artery and microvascular disease. Recent Advances: Increased attention has recently been given to defining mechanisms behind aging-mediated loss of vascular function and development of therapeutic strategies to restore youthful vascular responsiveness. The ultimate goal aims at providing new avenues for symptom management, reversal of tissue damage, and preventing or delaying of aging-induced vascular damage and dysfunction in the first place. Critical Issues: Our major objective is to describe how aging-associated mitochondrial dysfunction contributes to endothelial and smooth muscle dysfunction via dysregulated reactive oxygen species production, the clinical impact of this phenomenon, and to discuss emerging therapeutic strategies. Pathological changes in regulation of mitochondrial oxidative and nitrosative balance (Section 1) and mitochondrial dynamics of fission/fusion (Section 2) have widespread effects on the mechanisms underlying the ability of the vasculature to relax, leading to hyperconstriction with aging. We will focus on flow-mediated dilation, endothelial hyperpolarizing factors (Sections 3 and 4), and adrenergic receptors (Section 5), as outlined in Figure 1. The clinical implications of these changes on major adverse cardiac events and mortality are described (Section 6). Future Directions: We discuss antioxidative therapeutic strategies currently in development to restore mitochondrial redox homeostasis and subsequently vascular function and evaluate their potential clinical impact (Section 7). Antioxid. Redox Signal. 35, 974-1015.

Persistencia del conducto arterioso: Reporte de caso

The most common congenital heart disease found in dogs is the shunting patent ductus arteriosus (PDA), representing 25 to 30% of cases, mainly affecting purebred breeds and is more frequent in females. The ductus arteriosus (DA) is a structure present in fetal life, derived from the sixth aortic arch, connecting the pulmonary artery to the aorta. It helps in fetal circulation since lack of lung expansion offers great resistance to blood flow. At birth, the expansion of the lungs along with the alveolar and arterial PO2 increase stimulates the DA smooth muscle constriction, promoting its closure. PDA occurs when duct closure does not occur. It may be in the classic form, with the left-to-right shift, or the reverse form with the right-to-left shift. The diagnosis is made from clinical signs along with radiography, electrocardiography, echocardiography, and angiocardiography. Treatment is surgical, but as the patient may develop congestive heart failure (CHF), prior clinical treatment is required for possible arrhythmias and pulmonary edema. This paper aims to report a case of patent ductus arteriosus in a female Maltese canine, one-year-old. It had an audible machinery murmur on the left base of the heart, a palpable thrill, and complementary exams indicated severe cardiomegaly and CHF. After clinical treatment, the patient underwent surgical correction using the standard technique of ductus arteriosus ligation.

Biologic treatment options for severe asthma.

Asthma is a common condition that causes episodic expiratory airflow limitation due to bronchial smooth muscle constriction and airways inflammation resulting in increased respiratory symptoms and acute asthma exacerbations. Patients with severe asthma have relied on either recurrent courses or daily use of oral corticosteroids (OCS) to control their disease. However a high level of OCS exposure is associated with significant morbidity and mortality. In recent years the elucidation of the role of T2 inflammation underpinning asthma pathogenesis has led to the development of monoclonal antibody (mAb) therapies targeting this pathway. Established therapies now include omalizumab targeting IgE, mepolizumab and reslizumab targeting IL-5, benralizumab targeting the IL-5R and dupilumab targeting IL-4R. For many patients these therapies have been transformative and their use has additionally advanced our understanding of the immunology that underpins the disease. This article reviews the biologic therapies currently available for the treatment of severe asthma.

THE EFFECT OF INHALER USE SATISFACTION AMONG PATIENTS WITH ASTHMA ON THE DISEASE CONTROL

SESSION TITLE: Late-breaking Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: Asthma is a common inflammatory lung disorder of the upper respiratory tract that is characterized by reversible bronchial smooth muscle constriction, inflammation and hyperresponsiveness of the airways. Asthma guidelines emphasizes on the education, prevention, diagnosis and management of asthma. As shown in many studies factors such as age, gender, duration, severity of the disease, type of inhaler use, inhalation technique play an important role in drug effectiveness of chronic respiratory diseases including asthma. However, there are few studies that have assessed the impact of asthmatic patients’ satisfaction on the disease control. Patient satisfaction with their inhaler use is now gaining more attention in drug effectiveness. Most studies that discussed the asthmatic patients’ satisfaction with the control of the disease were not done in Saudi Arabia, nor in Middle East. That is why, our study focused more about how patient satisfaction can affect the control of the disease in the eastern province of KSA. This study aim to determine the impact of asthmatic patients' satisfaction upon disease control. We hypothesized that there is more disease control with patients who have high satisfaction upon their inhaler use. METHODS: An analytical cross-sectional study conducted across the eastern province asthmatic population. Total number of 150 patients estimated to be included in this study based on our inclusion criteria by filling two types of questionnaires Treatment Satisfaction questionnaire for Medication (TSQM) to assess the patient satisfaction and Asthma Control Test (ACT) to assess the disease control along with demographical data sheet. After obtaining the responses, the data has been analyzed by using unpaired t-test and chi square test with considering a p value of 0.05 to be statistically significant. RESULTS: 162 responds received from the online surveys that was distributed through WhatsApp and twitter across the eastern province of Saudi Arabia. 91 participants were excluded and 71 participants were included, mostly women (66.2%) followed by male (33.8%) with mean age of 28.8 years. From the 71 participants, majority of them had uncontrolled asthma (93%) while the minority had somewhat controlled asthma (7%). The results showed that the most common inhaler device used was MDI(71.8%) followed by SVN(18.3%) and lastly DPI(9.9%). There is no relationship between asthmatic patient satisfaction and the asthma control (P-value of 0.62). CONCLUSIONS: There is no association or relationship between the level of asthmatic patient satisfaction with the disease control thus the research hypothesis rejected. Further studies is needed to detect the impact of asthmatic patients' satisfaction upon disease control. CLINICAL IMPLICATIONS: Taking the asthmatic patient satisfaction in consideration upon the asthma medication as an important key factor will provide better disease control and management. DISCLOSURES: no disclosure on file for Sara Almesned; No relevant relationships by Nawal Alotaibi, source=Web Response No relevant relationships by Abeer Alshammeri, source=Web Response No relevant relationships by Abdullah Ghazwani, source=Web Response

ANTIHISTAMINIC ACTIVITY MODELS

Histamine is referred to as common allergic reactions and symptoms. Most of them are compared to histamine intolerance. Some common responses involved with this intolerance may vary but include headaches or migraines, nasal congestion or sinus problems, fatigue, hives, digestive problems, irregular menstrual cycle, nausea, and vomiting. Histamine is derived from a natural amino acid, S-histidine, through the histidine decarboxylase/ aromatic decarboxylase catalysis. Histamine is the compound that the mast cell generates for the immune response. Histamine promotes gastrointestinal secretion and induces capillary dilation, bronchial smooth muscle constriction, and reduced blood pressure. Antihistamines are medicinal products to treat allergic rhinitis and allergies. This includes the in vitro animal model and in-vivo tissue preparation antihistaminic activity. Animal models are significant instruments for understanding the pathological process of human illnesses in experimental medical science. Medicines associated with antihistamine include antiallergy, antivertigo, antimigraine, sedatives, antiemetic, etc. Elderly people are much more likely than youthful people to develop sleepiness from the use of antihistamines. The most common drugs used are cetirizine, levocetirizine, chlorpheniramine, diphenhydramine, loratadine, cimetidine, and fexofenadine. Animal models include histamine-induced bronchoconstriction, passive paw anaphylaxis, milk-induced leukocytosis and eosinophilia, clonidine, and haloperidol-induced catalepsy. While tissue models include isolated goat, and guinea-pig trachea chain preparation, as well as an isolated guinea pig, rat, mice ileum tissue preparation, and the dose-response curve of histamine, were plotted. The focus of the study had been on herbal plants and medicinal products, as they can effectively boost a variety of circumstances without significant adverse side effects. We can assess antihistaminic activity by using plant extracts or any synthetic drug.

Smooth Muscle Differentiation Is Essential for Airway Size, Tracheal Cartilage Segmentation, but Dispensable for Epithelial Branching.

Airway smooth muscle is best known for its role as an airway constrictor in diseases such as asthma. However, its function in lung development is debated. A prevalent model, supported by invitro data, posits that airway smooth muscle promotes lung branching through peristalsis and pushing intraluminal fluid to branching tips. Here, we test this model invivo by inactivating Myocardin, which prevented airway smooth muscle differentiation. We found that Myocardin mutants show normal branching, despite the absence of peristalsis. In contrast, tracheal cartilage, vasculature, and neural innervation patterns were all disrupted. Furthermore, airway diameter is reduced in the mutant, counter to the expectation that the absence of smooth muscle constriction would lead to a more relaxed and thereby wider airway. These findings together demonstrate that during development, while airway smooth muscle is dispensable for epithelial branching, it is integral for building the tracheal architecture and promoting airway growth.

The Effects of pH on the Structure and Bioavailability of Imidazobenzodiazepine-3-Carboxylate MIDD0301.

We describe the effects of pH on the structure and bioavailability of MIDD0301, an oral lead compound for asthma. MIDD0301 interacts with peripheral GABAA receptors to reduce lung inflammation and airway smooth muscle constriction. The structure of MIDD0301 combines basic imidazole and carboxylic acid function in the same diazepine scaffold, resulting in high solubility at neutral pH. Furthermore, we demonstrated that MIDD0301 can interconvert between a seven-membered ring structure at neutral pH and an acyclic compound at or below pH 3. Both structures have two stable conformers in solution that can be observed by 1H NMR at room temperature. Kinetic analysis showed opening and closing of the seven-membered ring of MIDD0301 at gastric and intestinal pH, occurring with different rate constants. However, in vivo studies showed that the interconversion kinetics are fast enough to yield similar MIDD0301 blood and lung concentrations for neutral and acidic formulations. Importantly, acidic and neutral formulations of MIDD0301 exhibit high lung distribution with low concentrations in brain. These findings demonstrate that MIDD0301 interconverts between stable structures at neutral and acidic pH without changes in bioavailability, further supporting its formulation as an oral asthma medication.

Medicinal Plants as Potential Hemostatic Agents.

Medicinal plants with a variety of phytochemical ingredients remain a potential source for new drug discovery. The use of medicinal herbs in a wide range of diseases and symptoms, such as bleeding, is prevalent in traditional and ethno medicine worldwide. Thus, this work provides a comprehensive review of medicinal plants or their isolated compounds, with respect to their ethno-medicinal use, which have demonstrated the stimulating effect on the hemostasis process. The relevant studies were withdrawn from electronic databases including Pubmed, EMBASE and Web of Science with a structured search methodology. The total of 17 medicinal plants with hemostatic activity were extracted. The most frequently studied plant families were Compositae, Lamiaceae, Fabaceae, and Asteraceae. Bioactive compounds exerting hemostatic activity included tannins, iridoid glycosides, glycoconjugate, lignan, saponins and phenolic compounds. The most attributed mechanisms include coagulation stimulation via increasing the factor XII activity and plasma fibrinogen levels, the fibrinolysis inhibition, vascular or smooth muscle constriction and platelet aggregation. The most important adverse effects of high dose extract or isolated compounds administration were hepatotoxicity and nephrotoxicity. This review provides a list of medicinal plants with hemostatic activity that could be used as valuable sources of new plant-based hemostatic agents. Furthermore, this could be practical in detecting possible interactions of plants with anticoagulant, antiplatelet, fibrinolytic and antifibrinolytic medications.

Development of a Novel Simple Gel Formulation Containing an Ion-Pair Complex of Diclofenac and Phenylephrine

Background and Aim: Since the pharmacological effects of diclofenac (DF) are short-lived because of its short half-life, prolongation of the pharmacological effect in a topical formulation is needed for more appropriate clinical use. For the enhancement of dermal accumulation and prolongation of the pharmacological effect of drugs, the aim of this study was to develop a simple gel formulation containing an ion-pair complex of DF and phenylephrine (PHE), which induce constriction of the vascular smooth muscles. Materials and Methods: The ion-pair complex was prepared by mixing sodium DF and an ethanolic solution of PHE. The formed complex was characterized by powder X-ray diffraction (PXRD) and Fourier-transform infrared (FT-IR) spectroscopy. The ion-pair complex for the gel formulation was prepared by mixing an equimolar concentration of 50% 1,3-butylene glycol and distilled aqueous solution of 2% xanthan gum, which was characterized by proton nuclear magnetic resonance (¹H-NMR). Skin permeation and accumulation of DF and PHE were evaluated by in vitro and in vivo studies. Results: From the results of PXRD and FT-IR, it was suggested that new crystalline peaks formed by the ion-pair complex and their complex interacted with the carboxyl group in DF and the amino group in PHE. In the gel formulation, the ion-pair complexes were detected by ¹H-NMR. The ion-pair complex enhanced the accumulation of DF in the skin in the in vitro study. On the other hand, PHE accumulation in the dermis increased with the ion-pair complex, as exhibited by the in vivo study. Conclusion: A new gel formulation containing the ion-pair complex of DF and PHE was developed, which improved the accumulation of DF in skin.

Abstract P2017: Angiotensin-Induced Constriction via Rho Kinase Activation in Pressure-Overloaded Rat Thoracic Aortas

Activation of the angiotensin II (Ang II) receptor increases myosin light chain (MLC) kinase activity and causes inactivation of MLC phosphatase thorough myosin phosphatase targeting subunit 1 (MYPT1) phosphorylation by Rho kinase. This results in MLC phosphorylation and subsequent smooth muscle constriction. However, the detailed mechanism of Rho kinase activation by Ang II is still unknown. The aim of this study was to clarify whether Ang II-induced constriction in pressure-overloaded rat thoracic aortas is mediated by Rho kinase activation through epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase 1 and 2 (Erk1/2), and janus kinase (JAK). Pressure-overload in the rat thoracic aortas was produced by suprarenal abdominal aortic coarctation. After 4 weeks, the thoracic aortas were excised for performing organ chamber experiments. Ang II was cumulatively added to reach a final concentration of a 0.1 – 1 μM. The inhibitors were added to 15 min prior to Ang II, and protein levels were measured by Western blotting. The contractile response to Ang II was significantly enhanced in the pressure-overloaded rats as compared to sham-operated ones [E max (% 40 mM KCl-induced constriction): sham; 44.6 ± 2.4, pressure-overload; 61.6 ± 2.2]. Ang II-induced constriction was attenuated by inhibitors of Rho kinase (E max : sham; 14.2 ± 5.3, pressure-overload; 6.8 ± 0.6), Erk1/2 (E max : sham; 21.2 ± 3.5, pressure-overload; 33.7 ± 3.5), and EGFR (E max : sham; 7.8 ± 2.0, pressure-overload; 26.6 ± 3.0) in both the sham-operated and pressure-overloaded rats. The Ang II-induced constriction was attenuated by JAK inhibitor (E max : sham; 41.9 ± 4.8, pressure-overload; 45.1 ± 4.2) in only pressure-overloaded rats. The protein levels of MYPT1 and JAK exhibited to increase in the pressure-overloaded rat thoracic aortas (MYPT1: sham; 1.0 ± 0.1, pressure-overload; 1.3 ± 0.1, JAK: sham; 1.0 ± 0.1, pressure-overload; 1.2 ± 0.1). These data suggest that Ang II-induced constriction is mediated by Rho kinase activation via EGFR, Erk1/2, and JAK in pressure-overloaded rat thoracic aortas. Moreover, Ang II-induced constriction was enhanced in pressure-overloaded rats probably because the protein levels of MYPT1 and JAK tended to increase in the thoracic aortas.