Expression of Alpha-Smooth Muscle Actin in Nasal Polyp Tissue of Chronic Rhinosinusitis Patients With and Without Aspirin Hypersensitivity

Background: Previous research has shown that myofibroblasts in the nasal/sinus mucosa are not only structural cells but also a rich source of inflammatory mediators. Thus, they influence the immune response and play an essential role in the pathogenesis of chronic rhinosinusitis with nasal polyposis. Previous research did not provide a clear answer to the question of whether the number of myofibroblasts in nasal polyps (NPs) affects the extent of sinus disease. This cross-sectional study investigates the relationship between the number of active myofibroblasts, eosinophil count, and clinical parameters in patients with NPs with and without aspirin sensitivity. Methods: Patients diagnosed with NPs, with and without aspirin sensitivity, and healthy subjects were assessed according to the severity of their symptoms as well as endoscopic and radiological findings. The quantification of myofibroblasts present in the surgically excised polyp tissue/healthy nasal mucosa was conducted based on the expression of alpha-smooth muscle actin (alpha-SMA) in the subepithelial and perivascular compartments. Eosinophils were counted in the subepithelium of the tissue samples from all subjects. Results: Forty-nine subjects were included: 23 NP patients without, 14 NP patients with aspirin sensitivity, and 12 control participants. The highest levels of alpha-SMA expression and eosinophil count were observed in NP patients with aspirin sensitivity and the lowest in healthy subjects (P < .001; P < .001, respectively). A strong correlation was noted between alpha-SMA expression and clinical parameters, particularly with disease extent evaluated radiologically and endoscopically. Conclusion: Our results suggest a positive correlation between the quantity of myofibroblasts and the severity of chronic inflammation in the sinonasal region. The number of myofibroblasts in the NP tissue may serve as a reliable marker for assessing the clinical status of the disease.