Nasal Potential Difference (NPD) Protocol in Chronic Rhinosinusitis

March 13, 2026 updated by: Brad Woodworth, MD, University of Alabama at Birmingham

Chloride Secretagogues for Acquired CFTR Dysfunction in Chronic Rhinosinusitis (NPD Protocol)

The purpose of this study is to determine if acquired (partial) Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) deficiency contributes substantially to the pathogenic mechanisms underlying Chronic Rhinosinusitis (CRS), creating a localized environment that impairs mucociliary clearance (MCC).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Detailed Description

Nasal Potential Difference (NPD) measurements will be conducted on participants. The NPD measurement, is a bioelectric assay of CFTR-dependent ion transport that has been used in a variety of protocols designed to detect CFTR function. A 4-Step protocol will be utilized. The nasal cavities will be perfused in a step-wise fashion with the following solutions: 1) Ringer's solution, 2) Ringer's solution + amiloride 100μM, 3) Low-Cl--containing solution, and 4) Low-Cl- + isoproterenol (10 µM). The potential difference will be monitored in nasal epithelium in comparison to an agar filled reference butterfly electrode placed in the volar aspect of the forearm, and connected via a calomel cell to a high impedance voltmeter.

Following placement of the subcutaneous reference bridge, the nasal probe will be secured 1-3 cm within the inferior meatus and secured in position at the most polarizing position. Each nare will then be sequentially perfused with Ringer solution. All nasal potential difference tracings will be scored independently by a single reviewer.

The investigator and an internal committee comprised of Gregory Fleming James Associate Scientists will oversee the safety of the study. Our internal committee is a multidisciplinary group consisting of physician and subspecialists who, collectively, have experience in treatment patients with cystic fibrosis and other airway disease in the conduct of randomized clinical trials. The primary responsibility of this committee is to protect the safety and welfare of subjects consenting to the investigator's procurement of remnant tissue during endoscopic sinus procedure. Members are responsible for reviewing procedural conduct, including acquisition of consents and materials, to protect patient well-being. An interim data safety review will be conducted on a yearly basis. The committee will consist of at least 3 members with clinical trials experience in airway diseases. During annual review, issues relating to the safety and process for acquiring human tissues will be reviewed. Summary reports from each annual meeting will be prepared and will address concerns about the procurement of tissue or any other information deemed pertinent to the review.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
20

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35244
        • Recruiting
        • University of Alabama at Birmingham
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients presenting to UAB for evaluation of CRS

Description

The patient eligibility criteria are designed to limit enrollment to healthy individuals and patients who clearly have CRS based on Sinus and Allergy health partnership criteria, but who are sufficiently well (both in terms of CRS and in terms of concomitant illness, such as asthma) to safely participate in study procedures and provide interpretable results.

Inclusion Criteria:

a. Patients with CRS will be diagnosed according to Sinus and Allergy Health Partnership symptom-based and objective criteria as follows: i. Duration of disease is qualified by continuous symptoms (≥ 2 major factors or at least 1 major factor & 2 minor symptoms; Table 2) for ≥ 12 consecutive weeks or ≥ 12 weeks of physical findings. ii. One of these signs of inflammation must be present and identified in association with ongoing symptoms.

  1. Discolored nasal drainage arising from the nasal passages, nasal polyps, or polypoid swelling as identified on physical examination with nasal endoscopy.
  2. Edema or erythema of the middle meatus or ethmoid bulla
  3. Generalized or localized erythema or edema. If it does not involve the middle meatus or ethmoid bulla, CT scan is performed to confirm a diagnosis.
  4. The CT scan must demonstrate isolated or diffuse mucosal thickening, bone changes, air-fluid levels. b. Age ≥ 19 years and Weight ≥ 50 kg c. Ability to perform NPD testing d. Negative pregnancy test (for females of childbearing potential) e. Written informed consent

Exclusion Criteria:

  1. Acute illness within 2 weeks before start of study treatment.
  2. History of major asthma attack within 2 months prior to start of study treatment.
  3. Change in intranasal medications (including use of corticosteroids, cromolyn, atrovent, phenylephrine, or oxymetazoline) within 14 days prior to start of study treatment.
  4. Positive hepatitis B surface antigen, hepatitis C antibody test, or human immunodeficiency virus (HIV) test.
  5. Hemoglobin <10 gm/dL and Serum albumin <2.5 g/dL.
  6. Abnormal liver function (serum ALT, AST, alkaline phosphatase, or total bilirubin >2 times upper limit of normal).
  7. Abnormal renal function (serum creatinine >1.5 times upper limit of normal).
  8. Pregnancy or breast feeding.
  9. History of solid organ or hematological transplantation
  10. History of autoimmune or granulomatous disorder.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Measurable Difference in CFTR function
Time Frame: One Year
A >-5 mV increase in total chloride secretion (change in NPD following nominal Cl- solution + amiloride + isoproterenol) is typically designated as evidence of measurable difference in CFTR function. Results of NPD measurements between CRS patients and healthy controls will be examined.
One Year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Alabama at Birmingham

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Heart, Lung, and Blood Institute (NHLBI)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Brad Woodworth, MD, University of Alabama at Birmingham

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2015

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 9, 2014

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 14, 2014

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 16, 2014

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 17, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 13, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • IRB-100930005
  • 1K08HL107142-01 (U.S. NIH Grant/Contract)

Drug and device information, study documents

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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