Viral rhinitis

Modulation of airway hyperresponsiveness by rhinovirus exposure

Rhinovirus (RV) exposure has been implicated in childhood development of wheeze evoking asthma and exacerbations of underlying airways disease. Studies such as the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) and Childhood Origins of ASThma (COAST) have identified RV as a pathogen inducing severe respiratory disease. RVs also modulate airway hyperresponsiveness (AHR), a key characteristic of such diseases. Although potential factors underlying mechanisms by which RV induces AHR have been postulated, the precise mechanisms of AHR following RV exposure remain elusive.

A challenge to RV-related research stems from inadequate models for study. While human models raise ethical concerns and are relatively difficult in terms of subject recruitment, murine models are limited by susceptibility of infection to the relatively uncommon minor group (RV-B) serotypes, strains that are generally associated with infrequent clinical respiratory virus infections. Although a transgenic mouse strain that has been developed has enhanced susceptibility for infection with the common major group (RV-A) serotypes, few studies have focused on RV in the context of allergic airways disease rather than understanding RV-induced AHR. Recently, the receptor for the virulent RV-C CDHR3, was identified, but a dearth of studies have examined RV-C-induced effects in humans.

Currently, the mechanisms by which RV infections modulate airway smooth muscle (ASM) shortening or excitation-contraction coupling remain elusive. Further, only one study has investigated the effects of RV on bronchodilatory mechanisms, with only speculation as to mechanisms underlying RV-mediated modulation of bronchoconstriction.

[Acute respiratory viral infections: Topical issues of diagnosis, prevention and treatment in therapeutic practice]

AIM

to assess the efficacy and safety of the medication Grippferon with loratadine for the prevention of acute respiratory viral infections (ARVI) and influenza during the epidemics.

MATERIAL AND METHODS

This study included 103 patients (67 men and 36 women) aged 18 to 52 years (mean age 35.3±3.2 years). During the first visit (september 2015), we collected patient history data on the average rate of ARVI and influenza for the past three years, the disease duration and its symptoms, presence of concomitant allergic pathologies (such as vasomotor rhinitis, hay fever and urticaria) and food allergies. Appropriate recommendations for the medication use were given to patients. During the second visit (may 2016), we collected follow-up cards and then analyzed the findings.

RESULTS

33 percent of the patients were fully compliant with the medication dosage regimen. In the first group (68 people with a history of one-two ARVI cases in the autumn-winter period for the past three years) the average number of ARVI cases in previous years was 1,53±0,23, by comparing with 0,69±0,16 (p<0.01) during the follow-up period, when medication Grippferon with loratadine was used. No ARVI cases were noted in 21 patients. In the second group (35 people with a history of three or more ARVI cases for the past three years) the average number of ARVI cases in previous years was 3,69±0,29, by comparing with 2,49±0,22 (p<0.05) during the follow-up period, when nasal ointment Grippferon with loratadine was applied. Two people reported that they did not have ARVI. We noted a positive ARVI symptoms dynamics in patients, who received treatment with the given medication. Specifically, a reduced duration of fever and intoxication periods as well as decreased catarrhal symptoms in the nasopharynx and oropharynx were observed.

CONCLUSION

The results of our study allow us to consider a new combined medication Grippferon with loratadine (nasal ointment) as an effective and safe medication for the prevention and treatment of influenza and acute respiratory viral infections in the complex therapy in adult patients, including patients with allergic history.

How does rhinovirus cause the common cold cough?

Cough is a protective reflex to prevent aspiration and can be triggered by a multitude of stimuli. The commonest form of cough is caused by upper respiratory tract infection and has no benefit to the host. The virus hijacks this natural defence mechanism in order to propagate itself through the population. Despite the resolution of the majority of cold symptoms within 2 weeks, cough can persist for some time thereafter. Unfortunately, the mechanism of infectious cough brought on by pathogenic viruses, such as human rhinovirus, during colds, remains elusive despite the extensive work that has been undertaken. For socioeconomic reasons, it is imperative we identify the mechanism of cough. There are several theories which have been proposed as the causative mechanism of cough in rhinovirus infection, encompassing a range of different processes. Those of which hold most promise are physical disruption of the epithelial lining, excess mucus production and an inflammatory response to rhinovirus infection which may be excessive. And finally, neuronal modulation, the most convincing hypothesis, is thought to potentiate cough long after the original stimulus has been cleared. All these hypotheses will be briefly covered in the following sections.

Oxymetazoline inhibits and resolves inflammatory reactions in human neutrophils

The nasal decongestant oxymetazoline (OMZ) exhibits anti-oxidative and anti-inflammatory properties (I. Beck-Speier et al., J Pharmacol Exp Ther. 2006;316:842-851). In a follow up study, we hypothesized that OMZ generates pro-resolving lipoxins being paralleled by production of immune-modulating prostaglandin E(2) (PGE(2)) and anti-inflammatory 15(S)-hydroxy-eicosatetraenoic acid [15(S)-HETE] and depletion of pro-inflammatory leukotriene B(4) (LTB(4)). Human neutrophils (PMN) were chosen as the cellular system. The effect of OMZ on these parameters as well as on respiratory burst activity and oxidative stress marker 8-isprostane was analyzed in unstimulated and co-stimulated PMN by ultrafine carbon particles (UCP) or opsonized zymosan (OZ), respectively. In unstimulated cells, OMZ induced formation of PGE(2), 15(S)-HETE, and LXA(4). The levels of LTB(4) and 8-isoprostane were not affected, whereas respiratory burst activity was drastically inhibited. In UCP- and OZ-stimulated control cells, all parameters were elevated. Here, OMZ maintained the increased levels of PGE(2), 15(S)-HETE, and LXA(4), but substantially suppressed levels of LTB(4) and 8-isoprostane and inhibited the respiratory burst activity. These findings suggest a switch from the pro-inflammatory eicosanoid class LTB(4) to the pro-resolving LXA(4). Since LXA(4) is most relevant in returning inflamed tissue to homeostasis, OMZ is postulated to terminate rhinitis-related inflammation, thus contributing to shortening of disease duration.

Oxymetazoline modulates proinflammatory cytokines and the T-cell stimulatory capacity of dendritic cells

Abstract:  The nasal decongestant oxymetazoline (OMZ) is frequently used in the topical treatment of rhinitis/sinusitis. As proinflammatory cytokines play a critical role in the development and maintenance of local inflammation, the aim of this study was to investigate the influence of OMZ on immune cells in order to diminish the mucosal infiltration of the nose. Peripheral blood mononuclear cells (PBMC) from buffy coats of healthy volunteers were isolated and stimulated in the presence or absence of OMZ. In addition, monocyte‐derived dendritic cells (DC) were generated and different concentrations of OMZ were added. DC phenotype and their T‐cell stimulatory properties were analysed. The vasoactive substance OMZ showed a concentration dependent inhibitory effect on T‐cell activation as well as a dominant effect on T‐cell stimulatory properties of DC. Low concentrations of OMZ inhibited the proliferation of polyclonally activated T cells. In addition, secretion of proinflammatory mediators such as the cytokines interleukin‐1β (IL‐1β), tumor necrosis factor‐α (TNF α), IL‐6 and IL‐8 were inhibited in the presence of physiological doses of OMZ. Interestingly, the addition of IL‐6 to DC‐T‐cell co‐culture was able to completely restore T‐cell proliferation. In conclusion, these findings indicate that the anti‐inflammatory properties of OMZ are partially mediated by the inhibition of proinflammatory cytokines as well as reduced T‐cell stimulatory capacity of DC resulting in a repressed stimulation of T cells. Therefore, the therapeutic benefit of OMZ can be explained in part by its immunomodulating effects in the topical treatment of nasal inflammation.

Oxymetazoline Inhibits Proinflammatory Reactions: Effect on Arachidonic Acid-Derived Metabolites

The nasal decongestant oxymetazoline effectively reduces rhinitis symptoms. We hypothesized that oxymetazoline affects arachidonic acid-derived metabolites concerning inflammatory and oxidative stress-dependent reactions. The ability of oxymetazoline to model pro- and anti-inflammatory and oxidative stress responses was evaluated in cell-free systems, including 5-lipoxygenase (5-LO) as proinflammatory, 15-lipoxygenase (15-LO) as anti-inflammatory enzymes, and oxidation of methionine by agglomerates of ultrafine carbon particles (UCPs), indicating oxidative stress. In a cellular approach using canine alveolar macrophages (AMs), the impact of oxymetazoline on phospholipase A(2) (PLA(2)) activity, respiratory burst and synthesis of prostaglandin E(2) (PGE(2)), 15(S)-hydroxy-eicosatetraenoic acid (15-HETE), leukotriene B(4) (LTB(4)), and 8-isoprostane was measured in the absence and presence of UCP or opsonized zymosan as particulate stimulants. In cell-free systems, oxymetazoline (0.4-1 mM) inhibited 5-LO but not 15-LO activity and did not alter UCP-induced oxidation of methionine. In AMs, oxymetazoline induced PLA(2) activity and 15-HETE at 1 mM, enhanced PGE(2) at 0.1 mM, strongly inhibited LTB(4) and respiratory burst at 0.4/0.1 mM (p < 0.05), but did not affect 8-isoprostane formation. In contrast, oxymetazoline did not alter UCP-induced PLA(2) activity and PGE(2) and 15-HETE formation in AMs but inhibited UCP-induced LTB(4) formation and respiratory burst at 0.1 mM and 8-isoprostane formation at 0.001 mM (p < 0.05). In opsonized zymosan-stimulated AMs, oxymetazoline inhibited LTB(4) formation and respiratory burst at 0.1 mM (p < 0.05). In conclusion, in canine AMs, oxymetazoline suppressed proinflammatory reactions including 5-LO activity, LTB(4) formation, and respiratory burst and prevented particle-induced oxidative stress, whereas PLA(2) activity and synthesis of immune-modulating PGE(2) and 15-HETE were not affected.