15-Hydroxyeicosatrienoic acid induces nasal congestion by changing vascular functions in mice.

BACKGROUND: Nasal congestion in allergic rhinitis (AR) is caused by vascular hyperpermeability and vascular relaxation of the nasal mucosa. We previously detected high levels of a lipoxygenation metabolite of dihomogammalinolenic acid, 15-hydroxy-8Z,11Z,13E-eicosatrienoic acid (15-HETrE) in the nasal lavage fluid of AR model mice. Here, we investigated the effects of 15-HETrE on vascular functions associated with nasal congestion. METHODS: We measured 15-HETrE levels in the nasal lavage fluid of ovalbumin-induced AR model mice and nasal discharge of patients with AR. We also assessed nasal congestion and vascular relaxation in mice. Vascular contractility was investigated using isolated mouse aortas. RESULTS: Five ovalbumin challenges increased 15-HETrE levels in AR model mice. 15-HETrE was also detected in patients who exhibiting AR-related symptoms. Intranasal administration of 15-HETrE elicited dyspnea-related behavior and decreased the nasal cavity volume in mice. Miles assay and whole-mount immunostaining revealed that 15-HETrE administration caused vascular hyperpermeability and relaxation of the nasal mucosa. Intravital imaging demonstrated that 15-HETrE relaxed the ear vessels that were precontracted via thromboxane receptor stimulation. Moreover, 15-HETrE dilated the isolated mouse aortas, and this effect was attenuated by K+ channel inhibitors and prostaglandin D2 (DP) and prostacyclin (IP) receptor antagonists. Additionally, vasodilatory effects of 15-HETrE were accompanied by an increase in intracellular cAMP levels. CONCLUSIONS: Our results indicate that 15-HETrE, whose levels are elevated in the nasal cavity upon AR, can be a novel lipid mediator that exacerbates nasal congestion. Moreover, it can stimulate DP and IP receptors and downstream K+ channels to dilate the nasal mucosal vasculature.

Autofluorescence multiphoton microscopy for visualization of tissue morphology and cellular dynamics in murine and human airways.

The basic understanding of inflammatory airway diseases greatly benefits from imaging the cellular dynamics of immune cells. Current imaging approaches focus on labeling specific cells to follow their dynamics but fail to visualize the surrounding tissue. To overcome this problem, we evaluated autofluorescence multiphoton microscopy for following the motion and interaction of cells in the airways in the context of tissue morphology. Freshly isolated murine tracheae from healthy mice and mice with experimental allergic airway inflammation were examined by autofluorescence multiphoton microscopy. In addition, fluorescently labeled ovalbumin and fluorophore-labeled antibodies were applied to visualize antigen uptake and to identify specific cell populations, respectively. The trachea in living mice was imaged to verify that the ex vivo preparation reflects the in vivo situation. Autofluorescence multiphoton microscopy was also tested to examine human tissue from patients in short-term tissue culture. Using autofluorescence, the epithelium, underlying cells, and fibers of the connective tissue, as well as blood vessels, were identified in isolated tracheae. Similar structures were visualized in living mice and in the human airway tissue. In explanted murine airways, mobile cells were localized within the tissue and we could follow their migration, interactions between individual cells, and their phagocytic activity. During allergic airway inflammation, increased number of eosinophil and neutrophil granulocytes were detected that moved within the connective tissue and immediately below the epithelium without damaging the epithelial cells or connective tissues. Contacts between granulocytes were transient lasting 3 min on average. Unexpectedly, prolonged interactions between granulocytes and antigen-uptaking cells were observed lasting for an average of 13 min. Our results indicate that autofluorescence-based imaging can detect previously unknown immune cell interactions in the airways. The method also holds the potential to be used during diagnostic procedures in humans if integrated into a bronchoscope.

Vein of foramen caecum: imaging findings.

Vein of foramen caecum has been classically described as a vein that connects nasal mucosa to the superior sagittal sinus in classic anatomy textbooks. However, its existence is controversial in literature. Herein, we demonstrated computed tomography and contrast enhanced magnetic resonance imaging findings of a tubular vascular structure extending to nasal mucosa and superior sagittal sinus.

Microvascular remodeling of nasal mucosa in allergic rhinitis induced by an allergen in Sprague-Dawley rats.

This study aimed to observe microvascular changes in the nasal mucosa of Sprague-Dawley (SD) rats with allergic rhinitis (AR) after persistent exposure to an allergen with fluticasone propionate (FP) treatment. Ninety healthy SD rats were randomly distributed into the control group (A, N = 30), the group with continued exposure to an allergen (B, N = 30), and FP treatment group (C, N = 30). The animals of the persistence group were subjected to persistent exposure to an allergen after 7 weeks of modeling of ovalbumin (OVA) provocation in the nasal mucosa for 16 weeks. At the 8th, 12th, and 16th week after OVA provocation, each group was euthanized at each time point: the FP treatment after OVA provocation, and animals of the control group were not stimulated with OVA and were sacrificed at the same time point. The nasal mucosa of 5 animals from each group was analyzed for the expression of vascular endothelial growth factor (VEGF), and another 5 animals were used to make micro vascular corrosion casts for a scanning electron microscope. The results demonstrate that FP has a strong inhibitory effect on angiogenesis in AR. Inhalation of FP had an antiangiogenic effect through inhibition of VEGF expression but does not completely reverse the remodeling of the nasal mucosa in the short term nor does it have complete control over the expression of VEGF mRNA.

First experiences with an individual nasal olive in patients with hereditary haemorrhagic telangiectasia (HHT).

Hereditary haemorrhagic teleangiectasia (HHT) is most notably characterized by vulnerable vascular formations of the nasal superficial mucosa. Epistaxis is one of the most common symptoms of the afflicted patients, with an incidence of more than 90 %. A variable series of treatments have been described, ranging from nasal ointments to the complete surgical occlusion of the nose. The objective of this pilot study is the presentation of first experiences in treating patients suffering from HHT and chronically recurrent epistaxis with an individual nasal olive made from silicone. Eleven patients (six men, five women) aging from 44 to 80 years with known HHT were treated at the ENT department of Homburg/Saar between October 2008 and July 2012 because of nasal bleeding by Nd:YAG laser or argon plasma coagulation. After the surgical treatment, an imprint of the nasal aditus was taken to manufacture an individual custom-made silicone nasal olive. Patients were wearing the nasal olive for 3-8 h a day. Check-ups were made every 6 months. Epistaxis severity score (ESS) was used pre- and post-nasal olive application. The observation period was 12-48 months. The utilization of the silicone nasal olive led to a distinct reduction of epistaxis events. Apart from the nasal olive, our patients needed no further treatment of the nose during the observation period except for a nasal ointment. Insertion and removal of the nasal olive were handled by the patients themselves. The local manipulation in handling the nasal olive caused no epistaxis itself. A significant improvement of the ESS and satisfaction was reported in all patients. Use of an individually manufactured silicone nasal olive is a promising extension to the established treatments of epistaxis in HHT patients. Tolerance towards this treatment by the patients was high due to the low personal burden and encumbrance. The extended use of the presented method in HHT patients may be beneficial. However, a more prolonged observation period is necessary in the future to judge the long-term efficiency of individual nasal olives.

Pharmacological evaluation of selective α2c-adrenergic agonists in experimental animal models of nasal congestion.

Nasal congestion is one of the most troublesome symptoms of many upper airways diseases. We characterized the effect of selective α2c-adrenergic agonists in animal models of nasal congestion. In porcine mucosa tissue, compound A and compound B contracted nasal veins with only modest effects on arteries. In in vivo experiments, we examined the nasal decongestant dose-response characteristics, pharmacokinetic/pharmacodynamic relationship, duration of action, potential development of tolerance, and topical efficacy of α2c-adrenergic agonists. Acoustic rhinometry was used to determine nasal cavity dimensions following intranasal compound 48/80 (1%, 75 µl). In feline experiments, compound 48/80 decreased nasal cavity volume and minimum cross-sectional areas by 77% and 40%, respectively. Oral administration of compound A (0.1-3.0 mg/kg), compound B (0.3-5.0 mg/kg), and d-pseudoephedrine (0.3 and 1.0 mg/kg) produced dose-dependent decongestion. Unlike d-pseudoephedrine, compounds A and B did not alter systolic blood pressure. The plasma exposure of compound A to produce a robust decongestion (EC(80)) was 500 nM, which related well to the duration of action of approximately 4.0 hours. No tolerance to the decongestant effect of compound A (1.0 mg/kg p.o.) was observed. To study the topical efficacies of compounds A and B, the drugs were given topically 30 minutes after compound 48/80 (a therapeutic paradigm) where both agents reversed nasal congestion. Finally, nasal-decongestive activity was confirmed in the dog. We demonstrate that α2c-adrenergic agonists behave as nasal decongestants without cardiovascular actions in animal models of upper airway congestion.

Elevated guanylate cyclase and cyclic-guanosine monophosphate-dependent protein kinase levels in nasal mucosae of antigen-challenged rats.

OBJECTIVE: In patients with severe allergic rhinitis, the most serious symptom is rhinostenosis, which is considered to be induced by a dilatation of plexus cavernosum. The vascular relaxing responses to chemical mediators are mainly mediated by the production of nitric oxide (NO). However, the exact mechanism(s) in nasal venoresponsiveness of allergic rhinitis is not fully understood. In the present study, we investigated the roles of soluble guanylate cyclase (sGC) and cyclic-guanosine monophosphate (c-GMP)-dependent protein kinase G (PKG) in venodilatation of nasal mucosae of antigen-challenged rats. METHODS: Actively sensitized rats were repeatedly challenged with aerosolized antigen (2,4-dinitrophenylated Ascaris suum). Twenty-four hours after the final antigen challenge, nasal septum mucosa was exposed surgically and observed directly in vivo under a stereoscopic microscope. The sodium nitroprusside (SNP) and 8-Br-cGMP (a PKG activator) were administered into arterial injection, and the venous diameters of nasal mucosa were observed. RESULTS: The intra-arterial injections of SNP and 8-Br-cGMP-induced venodilatation were significantly augmented in the nasal mucosae of repeatedly antigen-challenged rats. Furthermore, protein expressions of sGC and PKG were significantly increased in nasal mucosae of the antigen-challenged rats. CONCLUSION: The present findings suggest the idea that the promoted cGMP/PKG pathway may be involved in the enhanced NO-induced venodilatation in nasal mucosae of antigen-challenged rats.

[The phenomenon of vascular microthrombosis in mucoperichondrium associated with plastic closure of nasal septum perforations].

The objective of the present study was to identify specific hematological features characterizing the pathophysological processes of clinical significance associated with plastic closure of nasal septum perforations. Changes of clinical, biochemical, and coagulation-related blood characteristics developing as a result of the surgical treatment of the patients with ENT pathology were analysed. It was shown that D-dimer is a specific hematological characteristic that reflects the phenomenon of postoperative vascular microthrombosis in mucoperichondrial-periosteal flaps associated with plastic closure of nasal septum perforations. Based on the results of this study, the authors recommend to prescribe low-molecular weight heparins for prophylactic purposes to the patients undergoing plastic closure of nasal septum perforations.

The potential role of prostaglandin D2 in nasal congestion observed in a guinea pig model of allergic rhinitis.

BACKGROUND: Allergic rhinitis is the most common allergic disease, displaying the typical nasal symptom of congestion. Prostaglandin D(2) (PGD(2)), a chemical mediator released in large amounts by mast cells upon allergic stimulation in humans, is known to be involved in nasal congestion. However, the mechanism by which this congestion occurs remains unclear. METHODS: The effect of PGD(2) on the nasal airflow in guinea pigs was measured using a noninvasive approach that avoided any anesthetic effect. Isometric tension of isolated nasal mucosa and the nasal vascular corrosion resin cast technique were used to clarify the area of nasal mucosal vessels affected by PGD(2), and to examine the mechanism of PGD(2)-induced nasal congestion. Moreover, the involvement of second messengers in PGD(2)-induced mucosal relaxation was investigated. RESULTS: PGD(2) induced an increase in intranasal pressure in a guinea pig model of rhinitis. Additionally, sinusoidal microvessel dilatation appeared around the septum using the vascular corrosion resin cast technique in the nasal mucosa. Moreover, relaxation of the nasal mucosa following stimulation of the prostanoid DP-1 receptor was associated with cAMP levels in the tissue. CONCLUSIONS: PGD(2)-induced nasal congestion is caused by direct dilatation of the sinusoid vessels through the increase of cAMP levels in the nasal mucosa, demonstrating that the mechanism of PGD(2)-induced nasal congestion is different from other chemical mediators. Consequently, antagonists for the prostanoid DP-1 receptor would be an alternative approach for the relief of nasal congestion. Alternatively, the combined administration with antagonists for other mediators involved in nasal congestion may also be a valuable therapy for allergic rhinitis.

Using dynamic analysis of Laser-Doppler blood flowmetry to measure nasal mucosa bloody flow in postural changes.

BACKGROUND: The regulation of nasal mucosa blood flow (NMBF) is affected by multiple factors, such as the autonomic nervous system, medications, temperature, humidity, endocrine, even emotional stress and vision. The effects of postural changes on NMBF have been described in numerous studies. However, the results are far from consistent due to different experimental designs. OBJECTIVE: Dynamic analysis of Laser-Doppler blood flowmetry (LDBF) is employed to recognize the effect of postural changes on NMBF. METHODS: NMBF was continuously measured by LDBF in 14 participants with changing postures (sitting and supine). NMBF was measured in Blood Perfusion Unit (BPU), equivalent to the number of red blood cells multiplied by their mean velocity in a measured volume. RESULTS: NMBF increases significantly in a supine posture compared with that in a sitting posture. CONCLUSION: Our study demonstrates that NMBF is significantly influenced after initial postural change, suggesting that changes in posture may be regarded as an important factor regulating NMBF.

[The use of laser Doppler flowmetry for the estimation of the influence of intranasal medications on microcirculation in nasal cavity mucosa].

AIM OF THE STUDY: to investigate the influence of various intranasal medications on the microcirculatory bed in nasal cavity mucosa using the original method of laser Doppler flowmetry. METHODS: this comprehensive study of the influence of intranasal medicines on nasal cavity mucosa using laser Doppler flowmetry was designed to evaluate the mucociliary clearance, breathing efficiency of the nose, and subjective symptoms of its impairment. The outcomes of a single application of intranasal medications were estimated in 90 rhinologically healthy subjects; in 15 of them, the micrcirculatory blood flow in the nasal cavity was investigated in the early postoperative period with the use of intranasal decongestants and irrigation products. RESULTS: this study has demonstrated the relationship between the changes in the microcirculatory bed and the application of intranasal medications acting on nasal mucosa. Moreover, these agents were shown to affect intranasal mucosa and its microcirculatory bed following rhinological surgical interventions. Tachyphylaxis of the microcirculatory bed after the administration of the decongestants developed earlier than previously thought. At the came time, irrigation therapy exerted the beneficial effect on the state of the intranasal microcirculatory bed in the postoperative period.

Venous networks in the upper airways of bats: A histological and diceCT study.

Our knowledge of nasal cavity anatomy has grown considerably with the advent of micro-computed tomography (CT). More recently, a technique called diffusible iodine-based contrast-enhanced CT (diceCT) has rendered it possible to study nasal soft tissues. Using diceCT and histology, we aim to (a) explore the utility of these techniques for inferring the presence of venous sinuses that typify respiratory mucosa and (b) inquire whether distribution of vascular mucosa may relate to specialization for derived functions of the nasal cavity (i.e., nasal-emission of echolocation sounds) in bats. Matching histology and diceCT data indicate that diceCT can detect venous sinuses as either darkened, "empty" spaces, or radio-opaque islands when blood cells are present. Thus, we show that diceCT provides reliable information on vascular distribution in the mucosa of the nasal airways. Among the bats studied, a nonecholocating pteropodid (Cynopterus sphinx) and an oral-emitter of echolocation sounds (Eptesicus fuscus) possess venous sinus networks that drain into the sphenopalatine vein rostral to the nasopharynx. In contrast, nasopharyngeal passageways of nasal-emitting hipposiderids are notably packed with venous sinuses. The mucosae of the nasopharyngeal passageways are far less vascular in nasal-emitting phyllostomids, in which vascular mucosae are more widely distributed in the nasal cavity, and in some nectar-feeding species, a particularly large venous sinus is adjacent to the vomeronasal organ. Therefore, we do not find a common pattern of venous sinus distribution associated with nasal emission of sounds in phyllostomids and hipposiderids. Instead, vascular mucosa is more likely critical for air-conditioning and sometimes vomeronasal function in all bats.

Involvement of K(+) channels in the augmented nasal venous responsiveness to nitric oxide in rat model of allergic rhinitis.

OBJECTIVE: one of the factors of nasal obstruction observed in allergic rhinitis is thought to be a dilatation of microveins in nasal mucosa, although the exact mechanism(s) is not fully understood. In nasal mucosae of repeatedly antigen challenged rats, NO-induced venodilatation itself is augmented. In the present study, the roles of K(+) channels in sodium nitroprusside (NO donor; SNP)-induced venodilatation of nasal mucosae in antigen-challenged rats were investigated. METHODS: actively sensitized rats were repeatedly challenged with aerosolized antigen. Twenty-four hours after the final antigen challenge, nasal septum mucosa was exposed surgically and observed directly in vivo under a stereoscopic microscope. The 20µl reagents were administered onto the exposed septal mucosal surface, and the venous diameters of nasal mucosa were observed. RESULTS: the SNP-induced venodilatation of septal mucosa was markedly and significantly increased in the antigen-challenged rats. The SNP-induced venodilatation was significantly inhibited by pretreatment with either tetraethylammonium [TEA; a large-conductance Ca(2+) activated-K(+) (K(Ca)) and voltage dependent K(+) (Kv) channel inhibitor] or glibenclamide [an ATP sensitive K(+) (K(ATP)) channel inhibitor]. CONCLUSIONS: these findings suggest that NO-induced venodilatation is augmented in nasal mucosae of challenged rats, and K(+) channels play an important role in the augmented venous responsiveness to NO in nasal mucosae of repeatedly antigen challenged rats.

Reduced expression of angiotensin II and angiotensin receptor type 1 and type 2 in resistance arteries from nasal lesions in granulomatosis with polyangiitis (Wegener's granulomatosis).

OBJECTIVES: Angiotensin II (ANGII) is involved in vessel inflammation and is important in the development of cardiovascular disorders such as atherosclerosis. During active disease, patients with granulomatosis with polyangiitis (GPA; Wegener's granulomatosis) have accelerated atherosclerosis and ANGII inhibitors are recommended to these patients to reduce atherosclerosis. We assessed the hypothesis that the expression of ANGII and its receptors in arteries in granulomatous lesions change in GPA. METHODS: ANGII and angiotensin receptors were quantified in vessels from granulomatous lesions from patients with GPA using immunohistochemistry. Anti- ANGI type 1 (AT1) and type 2 (AT2) antibodies were applied on formalin-fixed and paraffin-embedded biopsies from nasal mucous membranes from eight patients with GPA and eight controls. RESULTS: ANGII expression was localized to the endothelial cells (ECs) in arteries and sparsely to vascular smooth muscle cells (VSMCs) in nasal biopsies. AT1 receptor (AT1R) staining was intense and located in the VSMCs in the medial layer of the control arteries. AT2 receptor (AT2R) immunostaining was faint and was located only in the ECs. Patients with GPA showed marked down-regulation of positively immunostained ECs for ANGII or AT2R, and a reduced number of AT1R in VSMCs. ANGII, AT1R, and AT2R staining was persistent on infiltrating leucocytes. CONCLUSIONS: These results suggest down-regulation of the angiotensin system in arteries in granulomatous nasal lesions in GPA. Inhibition of the angiotensin system may prove less efficient in inhibiting the vascular inflammation process in GPA.

Antigen-dependent rescue of nose-associated lymphoid tissue (NALT) development independent of LTbetaR and CXCR5 signaling.

Nose-associated lymphoid tissue (NALT) in the rodent upper respiratory tract develops postnatally and is considered to be independent of several factors known to be involved in the organogenesis of LN and Peyer's patches (PP). In this study we demonstrate that at least two different pathways result in NALT development. Following NALT anlage formation the intrinsic pathway relies on a signaling cascade including those mediated through the chemokine receptor CXCR5 and the lymphotoxin beta receptor (LTbetaR). This allows for the formation of high endothelial venules and thereby the recruitment of lymphocytes into NALT. Alternatively, high endothelial venule formation and lymphocyte recruitment can be induced in the NALT anlage by environmental signals, which are independent of LT-betaR and chemokine receptor CXCR5 signaling but in part rely on CD40 ligand. Thus, our study identifies a novel mechanism that facilitates the rescue of NALT development at late stages in adult life independent of the canonical LTbetaR-CXCR5 signaling axis.

Historical, pathophysiological, and therapeutic aspects of vidian neurectomy.

Vidian neurectomy yields dramatic relief of nasal hypersecretion in patients with allergic rhinitis. Clinical studies conducted on vidian neurectomized nasal mucosa have shown that nasal hypersecretion observed after challenging the nasal mucosa with antigen is caused by reflexively induced activation of the parasympathetic center secondary to stimulation of the sensory nerve terminals in the nasal mucosa by histamine. On the contrary, nasal mucosal swelling is caused mostly by the direct effects of chemical mediators on the nasal vasculature, although vascular reflex mediated by the noncholinergic parasympathetic nerve may be partially involved in the onset of nasal mucosal swelling after antigen challenge. Considering the long-term side effects of inhibition of lacrimation and possible partial recurrence of hyperreactive nasal symptoms observed after vidian neurectomy, less invasive endoscopic posterior nasal neurectomy is considered the treatment of choice for patients with allergic rhinitis who require surgical intervention.

Concomitant activity of histamine and cysteinyl leukotrienes on porcine nasal mucosal vessels and nasal inflammation in the rat.

BACKGROUND: Histamine and cysteinyl leukotrienes are pivotal mast cell mediators which contribute considerably and likely complementary to the symptoms of allergic rhinitis. Currently, we sought to explore the direct actions of histamine and leukotriene D(4) (LTD(4)), a cysteinyl leukotriene, on porcine nasal arteries and veins. We also studied combined blocks of histamine and cysteinyl leukotrienes using loratadine and montelukast in an in vivo model of allergy-mediated nasal inflammation. METHODS: For the evaluation of the action of histamine and LTD(4) on arteries and veins, porcine nasal mucosa was isolated and cut into slices (100-300 microm thick). Real-time images of the nasal arteries and veins were recorded and vessel activities estimated by changes in cross-sectional area before and after the tested drugs. For the in vivo studies, the effect of loratadine and montelukast given alone and in combination was examined on upper airway inflammation in ovalbumin-sensitized and -challenged Brown Norway rats. RESULTS: Both histamine (0.001-10 micromol/l) and LTD(4) (0.001-10 micromol/l) produced a concentration-dependent increase in the lumen area of nasal mucosa arteries and veins. Histamine (0.01 micromol/l) alone produced a 24 and 12% increase in cross-sectional areas of arteries and veins, respectively. LTD(4) (0.001 micromol/l) alone increased artery and vein dilation by about 17 and 9%, respectively. Combination treatment with histamine (0.01 micromol/l) and LTD(4) (0.001 micromol/l) increased vessel dilation by 65% (arteries) and 26% (veins). In our in vivo Brown Norway rat studies, oral loratadine (0.01-10 mg/kg) and montelukast (0.01-10 mg/kg) significantly reduced antigen-induced total nasal inflammatory cell infiltration in a dose-dependent manner. The antiinflammatory dose-response curve of loratadine was shifted to the left when studied in combination with montelukast (0.01 mg/kg). Similarly, the dose-response characteristics of montelukast (0.01-10 mg/kg) was shifted in the presence of loratadine (0.01 mg/kg). CONCLUSION: Our studies support the position that histamine and cysteinyl leukotrienes may act collaboratively to elicit allergic nasal pathologies such as upper airway inflammation and nasal vessel dilation (which may translate into increased nasal mucosal engorgement). Furthermore, the current results are supportive of the hypothesis that combined treatment of allergic rhinitis with an H(1) receptor antagonist and a CysLT(1) receptor antagonist may have greater benefit than sole treatment with these agents alone.