Reduced airway absorption in seasonal allergic rhinitis

Desmopressin dose requirements in patients with permanent arginine vasopressin deficiency: a tertiary center experience

PURPOSE

The desmopressin daily dose requirement is highly variable among patients with arginine vasopressin (AVP) deficiency (i.e. central diabetes insipidus) and few studies to date have evaluated this topic, with often inconclusive results. The aim of our study was to identify clinical and biochemical predictors of such dose requirements in a cohort of patients with a confirmed diagnosis of permanent AVP deficiency who have good and stable control under substitutive treatment.

METHODS

We retrospectively analyzed data of all patients with permanent AVP deficiency undergoing regular follow-up at our Division. Inclusion criteria were the presence of stable disease under therapy for at least 12 months and in good biochemical and clinical control. Patients with AVP deficiency who lacked intact thirst or had a disease duration of less than 12 months were excluded from the analysis.

RESULTS

Out of the 132 patients initially screened, 96 patients (M/F 44/52; age 51 [37-63] years) met the inclusion criteria. Patients on nasal spray therapy (n = 8) had a significantly longer disease duration (p = 0.002) than patients treated with oral lyophilizate (n = 88). In the bivariate analysis, considering only patients treated with the sublingual formulation, the drug dose was correlated positively with estimated glomerular filtration rate (eGFR) and weight (r = 0.410, p < 0.001; r = 0.224, p = 0.036, respectively) and negatively with age (r = - 0.433, p < 0.001). In the multivariate regression analysis taking into account age, weight, and eGFR, only age emerged as a significant predictor of the required sublingual desmopressin dose (β = - 1.426, p = 0.044).

CONCLUSION

Our data suggest that patient age appears to be the primary factor associated with the daily sublingual desmopressin dose required to achieve adequate clinical and biochemical control in patients with permanent AVP deficiency.

Well-controlled mucosal exudation of plasma proteins in airways with intact and regenerating epithelium

Superficial, systemic microcirculations, distinct from the pulmonary circulation, supply the mucosae of human nasal and conducting airways. Non-injurious, inflammatory challenges of the airway mucosa cause extravasation without overt mucosal oedema. Instead, likely reflecting minimal increases in basolateral hydrostatic pressure, circulating proteins/peptides of all sizes are transmitted paracellularly across the juxtaposed epithelial barrier. Thus, small volumes of extravasated, unfiltered bulk plasma appear on the mucosal surface at nasal and bronchial sites of challenge. Importantly, the plasma-exuding mucosa maintains barrier integrity against penetrability of inhaled molecules. Thus, one-way epithelial penetrability, strict localization, and well-controlled magnitude and duration are basic characteristics of the plasma exudation response in human intact airways. In vivo experiments in human-like airways demonstrate that local plasma exudation is also induced by non-sanguineous removal of epithelium over an intact basement membrane. This humoral response results in a protective, repair-promoting barrier kept together by a fibrin-fibronectin net. Plasma exudation stops once the provisional barrier is substituted by a new cellular cover consisting of speedily migrating repair cells, which may emanate from all types of epithelial cells bordering the denuded patch. Exuded plasma on the surface of human airways reflects physiological microvascular-epithelial cooperation in first line mucosal defense at sites of intact and regenerating epithelium.

Clinical Factors Affecting Daily Dosage of Desmopressin Orally Disintegrating Tablets in Arginine Vasopressin Deficiency

CONTEXT

Desmopressin orally disintegrating tablets (ODTs) are widely used to treat arginine vasopressin deficiency (AVP-D). However, limited information is available on the dosage regimen; the dosage for each patient is selected based on their response to the initiation dose.

OBJECTIVE

To investigate the relationships between clinical characteristics and the daily dose of ODTs and to identify factors that affect ODT dosages.

METHODS

This retrospective study included 209 adult patients with AVP-D. Patients were administered ODTs sublingually and instructed to restrict eating and drinking for 30 minutes after taking ODTs using a patient leaflet. ODT dose titration was conducted during hospitalization with close monitoring of urine output, body weight, and serum sodium levels. Multivariable linear regression models were applied to identify clinical factors associated with the daily dose of ODTs at discharge. We also evaluated the dosage at 1 year in 134 patients who were followed up in our hospital.

RESULTS

The median daily dose of ODTs at discharge was 90 µg (IQR 60-120 µg). Multivariable linear regression models identified sex, age, and estimated creatinine clearance (eCCr) as significant factors associated with the daily dose of ODTs, with eCCr having the strongest effect. After excluding patients recovering from AVP-D, 71% of those followed up at our hospital took the same daily dose at 1 year after discharge.

CONCLUSION

To achieve the safe and stable treatment of AVP-D, the daily dose of ODT needs to be selected based on a patient's sex, age, and eCCr under appropriate sublingual administration by patient education.

Acute seizure therapies in people with epilepsy: Fact or fiction? A U.S. Perspective

Patients with epilepsy (PWE) may experience seizure emergencies including acute repetitive seizures despite chronic treatment with daily antiseizure medications. Seizures may adversely impact routine daily activities and/or healthcare utilization and may impair the quality of life of patients with epilepsy and their caregivers. Seizures often occur at home, school, or work in a community setting. Appropriate treatment that is readily accessible for patients with seizure urgencies and emergencies is essential outside the hospital setting. When determining the best acute antiseizure therapy for PWE, clinicians need to consider all of the available rescue medications and their routes of administration including the safety and efficacy profiles. Benzodiazepines are a standard of care as a rescue therapy, yet there are several misconceptions about their use and safety. Reevaluating potential misconceptions and formulating best practices are necessary to maximize usage for each available option of acute therapy. We examine common beliefs associated with traditional use of acute seizure therapies to refute or support them based on the current level of evidence in the published literature.

Lack of observed impact of history or concomitant treatment of seasonal allergies or rhinitis on repeated doses of diazepam nasal spray administered per seizure episode in a day, safety, and tolerability: Interim results from a phase 3, open-label, 12-month repeat-dose safety study

Intranasal formulations are commonly used for drug delivery, and the literature has shown that seasonal allergies do not affect nasal administration of some agents. Diazepam nasal spray (Valtoco®) is a proprietary intranasal formulation with n-dodecyl-beta-d-maltoside (Intravail® A3) that is indicated for acute treatment of seizure clusters in patients with epilepsy aged 6 years and older. The analysis presented here is from an interim cutoff of a phase 3 open-label study evaluating the safety and tolerability of diazepam nasal spray. This analysis assessed whether seasonal allergies alter control of seizures with an intranasal formulation, using administration of a second dose as a surrogate efficacy endpoint. Of 158 evaluated patients with epilepsy having seizures despite a stable anti-seizure regimen, 62 patients had medical histories that included seasonal allergies or rhinitis. The results of this analysis show that seasonal allergies did not appear to influence use of a second dose; the groups of patients with and without a history of seasonal allergies both presented with low rates of seizure episodes for which a second dose was used, which suggests that there is not a major difference in pattern of use. Diazepam nasal spray demonstrated a similar safety and tolerability profile in patients with and without a history of seasonal allergies.

Clinical Practice Changes After Post-Market Safety Reports on Desmopressin Orally Disintegrating Tablet in Japan: A Single-Center Retrospective Study

Background

Desmopressin orally disintegrating tablet (ODT) was approved in March 2012 in Japan; the post-market safety reports, which warned about adequate initial dose of desmopressin ODT, were published in 2014. However, it is unclear how the warning affected physician and patient behavior.

Methods

We performed a retrospective single-center study to compare the clinical situation of Japanese central diabetes insipidus patients before and after the report.

Results

Thirty-four patients before October 2014 and 16 patients after November 2014 switched from intranasal desmopressin to desmopressin ODT. The mean follow-up period after the switch to desmopressin ODT was 38 ± 3 months. Patients switching after November 2014 tended to have lower ratios of oral to nasal desmopressin dose at switching and 3 months after the switch (at switching; P = 0.20, 3 months; P = 0.42, respectively), and higher ratios from 6 to 12 months than before October 2014 (6 months; P = 0.93, 9 months; P = 0.52, 12 months; P = 0.80, respectively). Relative doses per initial desmopressin ODT at 9 and 12 months were significantly higher in patients switching after November 2014 than in patients switching before October 2014 (9 months; P = 0.02, 12 months; P = 0.04, respectively). Moreover, logistic regression analysis revealed that the incidence of hyponatremia was dependent on the ratio of nasal to oral desmopressin dose (P = 0.02). In addition, in four out of six patients who had serum sodium level reduced below 130 mEq/L, hyponatremia occurred within 1 month after the switch.

Conclusions

A more gradual dose titration after the safety reports was performed, which involved the long-term safety of desmopressin ODT use. Vigilance of hyponatremia in early phase of desmopressin ODT use should be noted.

Airways exudation of plasma macromolecules: Innate defense, epithelial regeneration, and asthma

This review discusses in vivo airway aspects of plasma exudation in relation to current views on epithelial permeability and epithelial regeneration in health and disease. Microvascular-epithelial exudation of bulk plasma proteins characteristically occurs in asthmatic patients, being especially pronounced in those with severe and exacerbating asthma. Healthy human and guinea pig airways challenged by noninjurious histamine-leukotriene–type autacoids also respond through prompt mucosal exudation of nonsieved plasma macromolecules. Contrary to current beliefs, epithelial permeability in the opposite direction (ie, absorption of inhaled molecules) has not been increased in patients with asthma and allergic rhinitis or in acutely exuding healthy airways. A slightly increased subepithelial hydrostatic pressure produces such unidirectional outward perviousness to macromolecules. Lack of increased absorption permeability in asthmatic patients can further be reconciled with occurrence of epithelial shedding, leaving small patches of denuded basement membrane. Counteracting escalating barrier breaks, plasma exudation promptly covers the denuded patches. Here it creates and sustains a biologically active barrier involving a neutrophil-rich, fibrin-fibronectin net. Furthermore, in the plasma-derived milieu, all epithelial cell types bordering the denuded patch dedifferentiate and migrate from all sides to cover the denuded basement membrane. However, this speedy epithelial regeneration can come at a cost. Guinea pig in vivo studies demonstrate that patches of epithelial denudation regeneration are exudation hot spots evoking asthma-like features, including recruitment/activation of granulocytes, proliferation of fibrocytes/smooth muscle cells, and basement membrane thickening. In conclusion, nonsieved plasma macromolecules can operate on the intact airway mucosa as potent components of first-line innate immunity responses. Exuded plasma also takes center stage in epithelial regeneration. When exaggerated, epithelial regeneration can contribute to the inception and development of asthma.

Topical dsRNA challenges may induce overexpression of airway antiviral cytokines in symptomatic allergic disease. A pilot in vivo study in nasal airways

BACKGROUND

Airway challenge with dsRNA is of interest since this agent acts on TLR3 and mimics rhinoviral (RV) infection-induced interferons/cytokines. Contrasting frequent employment of dsRNA in epithelial cell cultures there is no information on effects of dsRNA administered to human airways in vivo. Here we explore effects of nasal dsRNA challenges in subjects with seasonal allergic rhinitis inside and outside Swedish birch pollen season.

METHODS

We examined effects of dsRNA in seven patients with seasonal allergic rhinitis. By being studied both inside and outside of an active pollen season they served as their own controls. Based on pilot experiments a repeat dose regimen of dsRNA, 4 × 100 μg, was given daily into the right nostril on two consecutive days; left nostril received corresponding saline challenges. Airway cells for gene analyses were obtained by nasal brushing shortly before the first challenge and 48 h after challenges.

RESULTS

Pollen counts and nasal symptoms indicated a significant season of allergic rhinitis. At the height of the pollen season, dsRNA challenges increased three antiviral proteins, interferons β and λ1 and IL-32, compared to saline challenges. By contrast, outside the pollen season dsRNA did not increase the expression of these antiviral proteins. dsRNA did not cause any symptoms outside the season nor did it increase the allergic symptoms evoked by natural pollen exposure.

CONCLUSION

These findings suggest the possibility that active mucosal inflammation, induced by natural allergen exposure in human airways, transiently increases in vivo antiviral responsiveness of airway surface cells.

Barrier-enforcing measures as treatment principle in allergic rhinitis: a systematic review

BACKGROUND AND OBJECTIVES

Barrier-enforcing measures have been suggested as treatment options for allergic rhinitis. This review identifies and describes the literature on the subject.

METHODS

Relevant publications were searched for in the PubMed database (search entries: 'allergic rhinitis' and 'treatment'). The evaluation comprised condition (seasonal or perennial allergic rhinitis), type of intervention, duration of treatment, study design, peer review status or not, number of test subjects, type of allergen exposure, and outcome in terms of effects or not on nasal symptoms of allergic rhinitis.

RESULTS

Fifteen studies were either identified in the PubMed database search or from the reference lists of identified publications. Seven were placebo-controlled, randomized, and peer-reviewed, and symptom-reducing effects were reported by all of these reports. Limitations of this review reflect that the remainder of the studies had inferior designs, particularly lack of placebo control.

CONCLUSIONS

Barrier-enforcing measures as achieved by nasal administrations of cellulose powder and microemulsions, respectively, have symptom-reducing effects in allergic rhinitis.

The effect of terbutaline on the absorption of pulmonary administered insulin in subjects with asthma

AIM

To investigate the effect of prior administration of a bronchodilator on the absorption of inhaled insulin in people with asthma treated with inhaled corticosteroids.

METHODS

A single-centre, randomized, open-label, two-period cross-over trial was carried out in 41 nondiabetic subjects with asthma treated with inhaled steroids, with reversible bronchoconstriction (Rev+; n= 25) or without reversible bronchoconstriction (Rev-; n= 16). A dose of 0.10 U kg(-1) inhaled human insulin was administered on each dosing day with or without prior administration of the bronchodilator terbutaline (in random order).

RESULTS

Prior administration of terbutaline led to a 44% increase in absorption of insulin over 6 h for the Rev+ group compared with no prior administration of bronchodilator [ratio (95% confidence interval) 1.44 (1.13, 1.82), P= 0.004], whereas no effect was seen for the Rev- or the whole group. The maximum insulin concentration (C(max)) increased by 34% for the Rev+ group (P = 0.018) and 17% for the whole group (P= 0.046), whereas no significant effect of prior terbutaline administration was seen for Rev-. The time to C(max) was not significantly different for the Rev+ group, whereas it was approximately 30% longer after bronchodilator administration for the Rev- group (P= 0.044) and the whole group (P= 0.032).

CONCLUSIONS

In people with asthma and reversible bronchoconstriction, the administration of a bronchodilator prior to administration of inhaled insulin led to increased absorption of insulin, whereas no effect on insulin absorption in subjects without significant reversibility could be detected.

Airway microvascular extravasation and luminal entry of plasma

Extravasation of plasma from postcapillary venules is a specific in vivo response to inflammatory insults. In the nasal and bronchial airways, extravasated plasma has a widespread distribution in the lamina propria, between the epithelial cells and in the airway lumen. This feature, in combination with the fact that the process involves extravasation of bulk plasma, with all peptides and proteins of plasma, indicates that plasma exudation contributes to the dramatic change of the mucosal milieu that characterizes airway inflammation. Accordingly, this process is of key importance to conditions such as allergic rhinitis and asthma. The means by which extravasated plasma participates in mucosal defence is physiological in the sense that it may operate on the surface of the epithelium without impairing its function as an absorption barrier. The flow of plasma into the airway lumen may thus wash away unwanted material from inter-epithelial cell spaces, exuded binding proteins may bind unwanted solutes non-specifically and extravasated immunoglobulins may neutralize allergens. In addition to the role as defence mechanism, extravasated plasma components may act as important pro-inflammatory factors. Furthermore, experimental data as well as observations in natural disease suggest that luminal levels of plasma proteins can be employed as an accessible index reflecting to what degree the airway mucosa is affected by inflammatory processes.

Allergic rhinitis: past, present and the future

Allergic rhinitis represents a global health issue affecting between 10% to 25% of the world population, with increasing prevalence over the last decade. Although often trivialized by patients and doctors, allergic rhinitis is a significant cause of morbidity, in addition to its substantial economic impact. While allergic rhinitis is an inflammatory disorder of the upper airways, inflammation alone is insufficient to explain the chronic nature of the disease. An exciting concept which has recently emerged in asthma concerns the role of the bronchial epithelium as a key regulator of airway inflammatory and remodelling responses in asthma. It has been shown by our group that the disruption and alteration in the function of the lower airway epithelium in asthma leads to the generation of a variety of stimuli that lead to the restructuring of the airway wall. This raises interesting questions regarding a similar role for the upper airway epithelium in allergic rhinitis. This review aims to interpret past and current research into allergic rhinitis, and to address specific areas where future research is warranted, particularly in relation to the possibility of an altered upper airway epithelial phenotype in allergic rhinitis.

Absorption across the nasal airway mucosa in house dust mite perennial allergic rhinitis

House dust mite allergens express protease activity and it has been suggested that this property has pathogenic effects by increasing airway absorption. In accordance, house dust mite allergens may increase mucosal permeability in vitro. The objective of the present study was to examine nasal absorption of desmopressin (1-deamino-8-D-arginine vasopressin) in patients with perennial house dust mite allergic rhinitis and in healthy subjects in vivo. Patients with perennial allergic rhinitis were examined after a 4-week treatment withdrawal period, when symptoms of allergic rhinitis occurred, and healthy subjects were examined together with the patients. Desmopressin (20 microg ml(-1)) was moved into the nasal cavity using a nasal pool-device that contained 15 ml fluid. The fluid was kept in the nasal cavity for 15 min and then recovered. Urine was collected for 24 h after the nasal administration and the urinary excretion of desmopressin was determined as an index of nasal absorption. The urinary excretion of desmopressin was 1148+/-535 pmol 24 h(-1) in patients with perennial house dust mite allergic rhinitis and 1012+/-291 pmol 24 h(-1) in healthy subjects. We conclude that nasal airway absorption of the 1067 Da peptide desmopressin is unaffected in perennial house dust mite allergic rhinitis compared with healthy subjects.

Loss of size-selectivity at histamine-induced exudation of plasma proteins in atopic nasal airways

Plasma proteins occur in the airway lumen in inflammatory airway diseases. This study tests the hypothesis that airway microvascular-epithelial exudation of plasma proteins, as induced by a non-injurious inflammatory mediator, is characterized by loss of size-selectivity. Using a nasal pool-device, the nasal mucosa of 10 allergic individuals, without current disease, was sequentially exposed to saline and histamine (40 and 400 microg ml(-1)). Nasal lavage fluid and blood-levels of albumin (69 kD) and alpha2-macroglobulin (720 kD) were determined. Histamine produced concentration-dependent exudation of albumin and alpha2-macroglobulin. The albumin/alpha2-macroglobulin concentration ratio of the saline lavage fluid (baseline) was 40+/-19. However, at the histamine challenges the ratios were 25+/-3 and 22+/-2, respectively, which did not differ from that of circulating plasma (22+/-2). We conclude that there is minor and size-selective luminal entry of plasma proteins at baseline. However, at concentration-dependent exudative responses to histamine, plasma proteins enter the airway lumen without being sieved. These data indicate that inflammatory stimulus-induced extravasation, lamina propria distribution and paracellular epithelial passage of plasma occur with minimal size-selectivity. Inferentially, the full immunological capacity of plasma proteins may readily be made available at the surface of human intact airway mucosa.

The effects of sensitization and hypersensitivity reaction on transepithelial antigen transport of rat nasal mucosa

METHODS

The prevalence of airway allergy is very high. The ways that antigen passes across the airway tract epithelial barrier are not well understood. This study uses a model antigen, horseradish peroxidase (HRP), to sensitize and challenge the respiratory tract in the rat model.

RESULTS

The results showed increases in HRP endosomes in nasal epithelial cells 5 minutes after HRP challenge in the sensitized rats compared with controls, which were further increased 30 minutes after HRP challenge, as well as with the paracellular region filled with HRP products. Meanwhile, mast cells were activated as shown by degranulation. Analysis of cell type showed that there were many more HRP endosomes in the nonciliated cells and there were many more nonciliated cells in the nasal mucosa of the sensitized rats.

CONCLUSION

The results demonstrate that sensitization promotes airway mucosal epithelial cells' uptake and transport of specific antigen and that mast cells may play certain roles in this process.

Nasal histamine reactivity; relationships to skin-test responses, allergen provocation and symptom severity in patients with long-continuing allergic rhinitis

It has been reported that skin-test reactivity and rhinitis symptom severity weaken in the course of time. A corresponding weakening might also be seen in non-specific nasal hyper-reactivity, but the relationships of these responses are poorly understood. Our aim was to measure nasal responsiveness to histamine in a series of patients with long-continuing allergic rhinitis and to compare these measurements with skin test responses, allergen provocation and changes in severity of allergic rhinitis symptoms. A total of 73 patients in whom allergic rhinitis had been verified over 20 years earlier were re-interviewed and re-investigated. Skin prick tests with common allergens were performed and the presence of nasal allergy was confirmed by allergen provocation. Non-specific nasal hyper-reactivity was determined with nasal histamine challenge using four concentrations of histamine phosphate. The response was registered by counting sneezes, recording changes in nasal discharge and mucosal swelling and measuring nasal airway resistance. Sneezing and discharge scores showed that milder non-specific nasal hyper-reactivity was associated with lack of reactivity in skin prick tests and nasal allergen challenge. No association was observed between allergy test results and changes in nasal airway resistance during the histamine provocation. In most patients the symptoms of rhinitis had become milder or disappeared during the follow-up, but the results of the histamine challenge showed no relationship with the changes in symptom severity. In patients with allergic rhinitis, reactivity to histamine is associated with a concomitant change in skin and nasal mucosal reactivity to allergens.