Nasal Potential Difference (NPD) Protocol in Chronic Rhinosinusitis

  • End date
    Jul 22, 2024
  • participants needed
  • sponsor
    University of Alabama at Birmingham
Updated on 4 October 2022
ct scan
cystic fibrosis transmembrane conductance regulator
nasal polyp


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).


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.

Condition Rhinosinusitis
Clinical Study IdentifierNCT02038166
SponsorUniversity of Alabama at Birmingham
Last Modified on4 October 2022


Yes No Not Sure

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
Edema or erythema of the middle meatus or ethmoid bulla
) 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
Discolored nasal drainage arising from the nasal passages, nasal polyps, or polypoid
swelling as identified on physical examination with nasal endoscopy
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
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

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