An observational study in Chronic Cough (CC), sponsored by McMaster University. Recruiting at 1 site in Canada. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-05-08.
Sponsored by McMaster University · Observational
Chronic cough is a common troublesome symptom which has a global prevalence of approximately 10%, but with wide variations across continents. Patients with refractory and unexplained chronic cough (RCC/UCC) often exhibit dysregulated vagal pathways, necessitating a neuronal biomarker for targeted treatment. ATP, involved in the ATP/P2X3 pathway, may serve as a potential biomarker due to its role in the cough reflex. The study aims to discover if ATP production by the airway epithelium is greater in RCC/UCC patients compared with healthy controls, if the epithelium is a source of ATP, whether gene and protein expression related to ATP production differs between these groups and whether ATP release is triggered by mechanical and chemical stimulation. Additionally, the study seeks to determine if biomarker gene expression signatures can differentiate RCC/UCC patients from healthy controls.
142 studies on the registry are indexed under Chronic Cough; 39 are open to participants now.
This study's planned enrollment of 30 is below the median of 100 across 37 observational studies indexed under Chronic Cough.
Browse Chronic Cough studies →McMaster University is the lead sponsor of 741 studies on the registry; 127 are open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 3 (43%) have results posted.
Counted across the registry records on this site, refreshed daily.
Healthy controls will be recruited through local advertising, existing study databases or participation in previous studies where they have given permission to be contacted. Participants with RCC/UCC will be recruited by the investigators from existing study databases, clinics at either of the following sites:
McMaster University Medical Centre, Department of Respiratory Medicine, 1200 Main St. West, Hamilton, Ontario, Canada, L8N 3Z5
Firestone Institute for Respiratory Health, St Joseph's Healthcare, 50 Charlton Ave E, Hamilton, ON L8N 4A6
Inclusion Criteria for RCC/UCC:
Inclusion Criteria for Healthy Controls:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
FEV1
From a breathing test (spirometry): how much air you can blow out in the first second. Often given as a percentage of what is expected for your age, height and sex.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Diagnostic Test: Bronchoscopy
Diagnostic Test: Bronchoscopy
Bronchoscopy will be performed in patients with refractory or unexplained chronic cough and healthy controls.
Difference in expressed genes
Expression of genes involved in intracellular ATP production, transport, extracellular metabolism in the airway epithelium will be compared in both RCC/UCC and healthy controls.
Time frame: At baseline
Difference Immune Cells and Cytokines
Investigate differences in the levels of neuroinflammatory mediators and immune cells from the respiratory airways and distal alveoli.
Time frame: 12 months
Gene Expression
To compare the differences in RCC/UCC and healthy control in gene expression profiling in bronchial biopsies (sub-epithelial dominant).
Time frame: At baseline
Difference in Nerve Morphology
Investigate differences in nerve length, nerve branch points, nerves expressive P2X3 receptors on airway sensory nerves expressing P2X3 receptor in RCC/UCC compared with healthy controls.
Time frame: baseline
Difference in ATP release
ATP release from the cultured bronchial epithelial cells (BEC) taken from RCC/UCC and healthy controls after exposure to dynamic mechanical stretch and environmental exposures (cigarette smoke and NO2).
Time frame: 5,15,30 minutes
Plan to share: No — This is an single visit of 15 patients with RCC/UCC compared with 15 Healthy Controls undergoing bronchoscopy at single centre in Hamilton, Ontario, Canada. Due to the small sample size individual level details will not be shared to protect confidentiality.
No publications or documents are linked to this record.
Started Nov 2024 (actual). Primary completion is estimated for Oct 2025, 10 months after the start.
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