Pharyngeal Inflammation on Positron Emission Tomography/Magnetic Resonance Imaging Before and After Obstructive Sleep Apnea Treatment
Annals of the American Thoracic Society, 2022
Cohen O., Kaufman A., Choi H., Khan S., Robson P., Suárez-Fariñas M., Mani V., Shah N.
| Disease area | Application area | Sample type | Products |
|---|---|---|---|
Respiratory Diseases | Pathophysiology | Nasal Fluid |  Olink Target 96 |
Abstract
Rationale: There is upper airway inflammation in OSA patients which reduces with CPAP therapy.
Objectives: Validate use of positron emission tomography/magnetic resonance imaging (PET/MRI) to quantify metabolic activity within the pharyngeal mucosa of patients with OSA against nasal lavage proteomics, and assess the impact of continuous positive airway pressure (CPAP) therapy.
Methods: Adults with OSA underwent [18F]-Fluoro-2-deoxy-D-glucose (FDG)-PET/MRI of the neck before and three months after initiating CPAP. Nasal lavage samples were collected. Inflammatory protein expression from samples was analyzed using the Olink platform. Upper airway imaging segmentation was performed. Target-to-background ratio (TBRmax) were calculated from target pharyngeal maximum standard uptake values (SUV) and personalized background mean SUV. Most-diseased segment-TBRmax were identified per participant at locations with highest PET avidity. Correlation analysis was performed between baseline TBRmax and nasal lavage proteomics. TBRmax was compared pre- and post-CPAP using linear mixed-effect models.
Results: Among thirty-eight participants, baseline mean age was 46.3 years (SD 12.5), 21% were female, mean BMI was 30.9 kg/m2 (SD 4.6), and mean pRDI was 31 events/hour (SD 16.4). There was a significant positive correlation between pharyngeal mucosa most-diseased segment-TBRmax and nasal lavage proteomic inflammation (r=0.41 [p<0.001, FDR=0.002]). Primary analysis revealed a reduction in the most-diseased segment-TBRmax after median 2.91 months of CPAP therapy (-0.86 [SE±0.30 p=0.007]). Stratified analysis by smoking status revealed a significantly decreased most-diseased segment-TBRmax post-CPAP therapy among never smokers but not among ever smokers (-1.01 [SE±0.39, p=0.015] versus -0.64 [SE±0.49, p=0.201]). Conclusions: CPAP therapy reduces metabolic activity measured by PET/MRI within the upper airway of adults with OSA. Further, PET/MRI measures of upper airway metabolic activity correlate with a non-invasive marker of inflammation, i.e., nasal lavage inflammatory protein expression.