Sensory Hyperreactivity and Chemical Sensitivity, Tilia
Home
About this website
News
På svenska
Nyheter
Auf Deutsch
Download books
Research group
Funding sources
Research abstracts
Links
 

Latest update: 2011-02-27

Nyheter

De senaste forskningsresultaten om SHR

1. Inandat etanol kan förstärka symptomen vid SHR
Femton patienter med SHR och 15 friska kontrollpersoner fick andas in olika koncentrationer av etanol och därefter genomgå ett hosttest med capsaicin. Den starkaste etanolkoncentrationen medförde att känsligheten för capsaicin ökade, det vill säga patienterna hostade mer om de först andats in etanol. Eftersom parfym retar samma nervreceptorer som capsaicin blir slutsatsen att etanol som är ett vanligt lösningsmedel bland annat i parfym kan förstärka hosta och andra luftvägssymptom som utlöses av dofter och kemikalier. Artikeln är publicerad enligt nedan:

Inhaled ethanol potentiates the cough response to capsaicin in patients with airway sensory hyperreactivity

Authors: Millqvist E, Ternesten-Hasséus E, Bende M

Journal: Pulm Pharmacol Ther. 2008 Oct;21(5):794-7

A suggested explanation for airway symptoms induced by chemicals and scents is sensory hyperreactivity (SHR) of airway mucosal nerves. Patients with SHR have increased cough sensitivity to inhaled capsaicin, mediated by transient receptor potential (TRP) ion channels. In animal experiments, some TRP receptors are potentiated by ethanol, which is why in this study, the aim was to evaluate whether a pre-inhalation of ethanol could influence the capsaicin cough response in patients with SHR. Fifteen patients with SHR and 15 healthy controls were provoked on three occasions with two concentrations of inhaled capsaicin. Before each capsaicin provocation, a pre-inhalation of saline or one of two concentrations of ethanol was given in a double-blind, randomized fashion. The participants reacted in a dose-dependent way with cough on the capsaicin inhalations. Among the patients, but not in the control group, pre-inhalation of ethanol increased the cough response dose-dependently. The results suggest that the pathophysiology of SHR is related to airway mucosal TRP receptors in the sensory nerves. In scented products, the combination of ethanol as a solvent and perfume may augment an airway reaction in sensitive individuals.

PMID: 18621137 [PubMed - indexed for MEDLINE]
The full text is available at:
http://www.ncbi.nlm.nih.gov/pubmed/18621137



2. Ansträngning i kall luft utlöser hosta och ökar känsligheten för capsaicin hos patienter med SHR
Patienter med SHR som genomgick ett ansträngningsprov på en testcykel i en köldkammare fick symptom i form av hosta "tungandning" men inte någon luftvägskramp (som vid astma). Efter ansträngningstestet ökade känsligheten för inandat capsaicin (de hostade mera). En grupp med friska kontrollpersoner fick inte motsvarande besvär och inte heller ökad capsaicinkänslighet efter ansträngningstestet. Artikeln är publicerad enligt nedan:

Dyspnea from exercise in cold air is not always asthma

Authors: Ternesten-Hasseus E, Johansson EL, Bende M, Millqvist E

Journal: J Asthma 2008;45:705-9.

In the absence of other explanations, exercise-induced dyspnea is often labeled as a manifestation of asthma. The aim of this study was to use exercise provocation in cold air among patients with exercise-induced dyspnea, but without any bronchoconstriction, in order to study induced symptoms and different physiological parameters and to measure the possible influence of exercise in cold air on capsaicin cough sensitivity. Eleven patients with exercise-induced dyspnea but no asthma, along with 11 healthy controls, performed a capsaicin inhalation provocation on two occasions. One of these provocations was preceded by an exercise provocation in a cold chamber. Number of coughs, airway symptoms, spirometry, respiratory rate, pulse rate, end-tidal CO(2), and PSaO(2) were registered. During exercise, the patients coughed more than the controls and also had more airway symptoms. After exercise provocation, spirometry values remained unchanged, but capsaicin cough sensitivity was increased and end-tidal CO(2) decreased among the patients, both in comparison to the controls and in comparison to the patients themselves prior to exercise. Exercise-induced dyspnea may be associated with hypocapnia from hyperventilation and increased capsaicin cough sensitivity. The diagnosis of exercise-induced asthma should be questioned when the patient has no signs of bronchoconstriction.

PMID: 18951264 [PubMed - indexed for MEDLINE]
The full text is available at:
http://www.ncbi.nlm.nih.gov/pubmed/18951264



3. Inandad torr luft minskar känsligheten för capsaicin hos patienter med SHR
Patienter med kronisk hosta och SHR hostade mindre av inandat capsaicin om capsaicintestet föregicks av en så kallad torrluftsprovokation (häftig inandning av torrluft). Orsakerna till detta är fortfarande oklara men studien bidrar med värdefull kunskap som på sikt kan medverka till att vi bättre förstår de bakomliggande mekanismerna vid SHR. Artikeln är publicerad enligt nedan:

Down-regulation of cough sensitivity after eucapnic dry air provocation in chronic idiopathic cough

Authors: Johansson EL, Ternesten-Hasséus E, Millqvist E

Journal: Pulm Pharmacol Ther. 2009 Dec;22(6):543-7

Down-regulation of cough sensitivity in humans is rarely discussed in terms other than pharmacological treatment of cough or hypersensitive cough reflex. Chronic cough and increased cough sensitivity could be due to a number of airway and other diseases. When such conditions are excluded, there still remains a group of patients with no evident medical explanation for persistent coughing; such patients are often described as having "chronic idiopathic cough". The aim of this study was to use a standardized eucapnic dry air provocation among patients with chronic idiopathic cough in order to study physiological parameters and measure their possible influence on capsaicin cough sensitivity. Fourteen female patients with chronic idiopathic cough and ten healthy controls underwent a capsaicin inhalation provocation on two occasions. In all patients, irritating environmental factors were known to induce cough and airway symptoms. One of the two capsaicin provocations was preceded by a eucapnic dry air provocation. Number of coughs, spirometry, respiratory rate, pulse rate, end-tidal CO(2), and oxygen saturation by pulse oximetry (PSaO(2)) were registered and compared. The patients showed increased capsaicin sensitivity compared with the control subjects. This sensitivity was decreased when the capsaicin test was preceded by a eucapnic dry air provocation. Before the dry air provocation and after the capsaicin provocations, end-tidal CO(2) was decreased among the patients in comparison with the controls. After dry air provocation, spirometry values remained unchanged. The results suggest that in patients with chronic idiopathic cough, physiological down-regulation of the cough sensitivity is possible with a eucapnic dry air provocation.

PMID: 19646543 [PubMed - indexed for MEDLINE]
The full text is available at: http://www.ncbi.nlm.nih.gov/pubmed/19646543



4. Samband mellan astma och SHR
Syftet med denna studie var att undersöka SHR-förekomsten vid astma. Patienter med typisk astma fick besvara frågeformulär om känslighet för dofter och kemikalier samt frågor som speglade psykisk ohälsa som ångest och depression. Patienterna fick andas in capsaicin (ett standardiserat så kallat capsaicntest) och hostkänsligheten registrerades. Sammanfattningsvis var inte SHR vanligare bland patienter med astma än den förekomst som en tidigare studie visade bland den vanliga svenska befolkningen. Strikta kriterier hade satts upp både vad beträffar uppgiven känslighet för dofter i kombination med hostkänslighet för capsaicin för att kunna få diagnosen SHR. Även om patienter med astma inte nådde tröskeln för SHR var såväl angiven känslighet för dofter som capsaicinkänsligheten förhöjd. Studien visade inte några tecken till att SHR i högre grad skulle vara kopplat till ångest och depression. Artikeln är publicerad enligt nedan:

Relationship of airway sensory hyperreactivity to asthma and psychiatric morbidity

Authors: Johansson A, Millqvist E, Bende M

Journal: Ann Allergy Asthma Immunol. 2010 Jul;105(1):20-3

BACKGROUND: Patients with airway symptoms induced by chemicals and odors are common in allergy clinics, but the problems cannot be explained by allergic or asthmatic reactions. Previous studies have shown that these patients often have increased sensitivity to inhaled capsaicin, which is known to reflect sensory reactivity; a diagnosis of airway sensory hyperreactivity (SHR) has been suggested for this condition.
OBJECTIVES: To examine the relationship between asthma and SHR and to investigate whether patients with SHR show signs of increased psychiatric morbidity.
METHODS: This study included 724 patients who were attending an allergy center because of suspected allergy or asthma. All the patients completed a quantitative questionnaire on self-reported affective reactions and behavioral disruptions caused by odorous/pungent substances. A standardized capsaicin inhalation test was performed and a questionnaire to assess psychiatric morbidity was administered in patients with pronounced chemical sensitivity to identify those with SHR.
RESULTS: The prevalence of SHR was approximately 6% in asthmatic patients in the allergy center population, which is in accordance with the prevalence in a general population. There was no significant indication that SHR was related to either depression or anxiety.
CONCLUSION: There is no strong relationship between SHR and either asthma or psychiatric morbidity.

PMID: 20642199 [PubMed - in process]
The full text is available at: http://www.ncbi.nlm.nih.gov/pubmed/20642199



5. The cough hypersensitivity syndrome
En grupp forskare i England har nyligen lanserat ett nytt begrepp för kronisk hosta utan påtaglig förklaring: The cough hypersensitivity syndrome eller fritt översatt till svenska "Överkänslighetshosta". Detta begrepp inkluderar patienter med känslighet för dofter och kemikalier som kan få diagnosen SHR men även andra grupper av patienter med hosta av okänd anledning. Här är ett exempel på hur olika grenar inom luftvägsforskning försöker hitta en gemensam plattform. Artikeln är publicerad enligt nedan:

Cough hypersensitivity syndrome: a distinct clinical entity

Authors: Morice AH, Faruqi S, Wright CE, Thompson R, Bland JM

Journal: Lung. 2011 Feb;189(1):73-9

We postulate that most patients with chronic cough have a single discrete clinical entity: Cough Hypersensitivity Syndrome. We constructed a questionnaire that elicits the major components of the syndrome. Here we describe the validation of this questionnaire. Following iterative development, the Hull Airway Reflux Questionnaire (HARQ) was administered to patients and normal volunteers. It is self-administered and comprises 14 items with a maximum score of 70. Unselected patients were recruited sequentially from the Hull Cough Clinic. Preclinic questionnaires were compared with those obtained at the clinic. Responsiveness was assessed 2 months after the clinic visit. One hundred eighty-five patients and 70 normal volunteers were included in this study. There was a marked difference in HARQ scores between patients with chronic cough and normal volunteers. The sensitivity (94%) and specificity (95%) of the HARQ was high, with an area under the ROC curve of 0.99. All items of the scale significantly correlated positively with others in the scale and with the total score. On repeatability testing using Cohen's kappa with quadratic weights, significant agreement was noted for all items. Good correlation was observed between the total scores (r = 0.78). The questionnaire was also responsive to treatment; the minimum clinically significant change was estimated to be 16 points. We have demonstrated the HARQ to have good construct and criterion validity. It is both reproducible and responsive to change. It can be used as a diagnostic instrument and demonstrates that chronic cough represents a single coherent entity: Cough Hypersensitivity Syndrome.

PMID: 21240613 [PubMed - in process]
The full text is available at: http://www.ncbi.nlm.nih.gov/pubmed/21240613