Combined use of rheology and portable low-field NMR in cystic fibrosis patients

Michela Abrami; Massimo Maschio; Massimo Conese; Marco Confalonieri; Fabio Gerin; Barbara Dapas; Rossella Farra; Alessandra Adrover; Lucio Torelli; Barbara Ruaro; Gabriele Grassi; Mario Grassi

doi:10.1016/j.rmed.2021.106623

Combined use of rheology and portable low-field NMR in cystic fibrosis patients

Respir Med. 2021 Nov-Dec:189:106623. doi: 10.1016/j.rmed.2021.106623. Epub 2021 Sep 25.

Authors

Affiliations

¹ Department of Engineering and Architecture, University of Trieste, Via Valerio 6/A, I-34127, Trieste, Italy.
² Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Via Dell'Istria, 65, I-34137, Trieste, Italy.
³ Department of Medical and Surgical Sciences, Foggia University, Ospedali Riuniti, Via L. Pinto, 1, I-71122, Foggia, Italy.
⁴ Cattinara University Hospital, Pulmonology Department, Strada di Fiume 447, I-34149, Trieste, Italy.
⁵ Department of Life Sciences, Cattinara University Hospital, Trieste University, Strada di Fiume 447, I-34149, Trieste, Italy.
⁶ Clinical Department of Medical, Surgical and Health Sciences, Cattinara University Hospital, Trieste University, Strada di Fiume 447, I-34149, Trieste, Italy.
⁷ Department of Chemical Engineering, Materials and Environment, Sapienza University of Roma, Via Eudossiana 18, I-00184, Rome, Italy.
⁸ Department of Life Sciences, Cattinara University Hospital, Trieste University, Strada di Fiume 447, I-34149, Trieste, Italy. Electronic address: ggrassi@units.it.

PMID: 34624628
DOI: 10.1016/j.rmed.2021.106623

Abstract

Background: As most cystic fibrosis (CF) patients progress to respiratory failure, lung functionality assessment is pivotal. We previously developed a test that indirectly monitors airways (inflammation/functional test) by measuring the spin-spin relaxation time (T_2m) of the water hydrogens present in CF sputum. Here the T_2m significance in the monitoring of CF lung disease was further investigated by studying the correlation of T_2m with: 1) sputum viscoelasticity, 2) mucociliary clearability index (MCI)/cough clearability index (CCI) and 3) sputum average mesh-size.

Methods: Sputum samples from 25 consenting CF subjects were analyzed by rheology tests (elastic modulus G and zero shear viscosity η₀) and Low Field Nuclear Magnetic (LF-NMR) resonance (T_2m). MCI/CCI were calculated from the rheological parameters. The average mesh-size (ξ) of the sputum structure was then evaluated by rheology/LF-NMR, together with FEV₁ for each patient.

Results: There was an inverse correlation between G and η₀ versus T_2m, indicating that a worsening of the lung condition (T_2m-FEV₁ drop) is paralleled by an increase in sputum viscoelasticity (G and η₀) favoring mucus stasis/inflammation. A direct correlation was also observed between T_2m and MCI/CCI, showing that T_2m provides information as to airway mucus clearing. Moreover, there was a direct correlation between T_2m and the average sputum mesh size (ξ).

Conclusions: We demonstrated a correlation between T_2m (measured in CF patient's sputum) and the sputum viscoelasticity/average mesh-size and with MCI/CCI, parameters related to airway mucus clearing. Thus, the present data strengthen the potential of our test to provide indirect monitoring of airway disease course in CF patients as T_2m depends on mucus solid concentration and nanostructure.

Keywords: Cystic fibrosis; Low field NMR; Rheology; Sputum.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Aged, 80 and over
Cystic Fibrosis / drug therapy
Cystic Fibrosis / physiopathology*
Female
Humans
Magnetic Resonance Spectroscopy*
Male
Middle Aged
Mucociliary Clearance
Respiratory Function Tests
Rheology*
Sputum / chemistry
Viscosity