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Background: Obesity associated with various complications has increased worldwide. Body weight gain alters lipid metabolites (especially sphingolipids) contributing to obesity‐induced inflammation. However, the significance of the metabolites in the development of obese asthma is not yet clear. Methods: The serum levels of sphingolipids were measured using liquid chromatography‐tandem mass spectrometry in obese controls (n = 7) and patients with asthma: the obese group (BMI > 25 kg/m2, n = 13) vs the nonobese (n = 28) group. To examine the relationship between metabolic changes in sphingolipids and macrophage polarization, public microarray data were analyzed. In addition, the alteration in sphingolipid metabolism was investigated in wild‐type BALB/c mice fed a high‐fat diet. Results: The obese asthma had higher levels of serum C18:0 and C20:0 ceramides than the nonobese asthma group (P =.028 and P =.040, respectively). The value of the serum C18:0 ceramide (184.3 ng/mL) for discriminating the obese asthma from the nonobese asthma group showed 53.9% sensitivity and 85.7% specificity (AUC = 0.721, P =.024). The microarray data showed significantly increased ceramide synthesis and metabolic shift to ceramide accumulation during M1 macrophage polarization in humans. Increased airway hyperresponsiveness, M1 macrophage polarization, and C18:0 ceramide levels were noted in obese mice, but not in nonobese mice. Increased expression of ceramide synthase (CerS) 1 and CerS6 (not CerS2) was noted in lung tissues of obese mice. Conclusion: Alteration in sphingolipid metabolism favoring ceramide accumulation (especially long‐chain ceramides) may contribute to developing obese asthma. [ABSTRACT FROM AUTHOR]

Background: Asthma is associated with inflammatory dysregulation, but the underlying metabolic signatures are unclear. This study aimed to classify asthma inflammatory phenotypes based on cellular and metabolic features. Methods: To determine cellular and metabolic profiles, we assessed inflammatory cell markers using flow cytometry, sphingolipid (SL) metabolites using LC‐MS/MS, and serum cytokines using ELISA. Targeted gene polymorphisms were determined to identify genetic predispositions related to the asthma inflammatory phenotype. Results: In total, 137 patients with asthma and 20 healthy controls (HCs) were enrolled. Distinct cellular and metabolic profiles were found between them; patients with asthma showed increased expressions of inflammatory cell markers and higher levels of SL metabolites compared to HCs (P <.05 for all). Cellular markers (CD66+ neutrophils, platelet‐adherent eosinophils) and SL metabolic markers (C16:0 and C24:0 ceramides) for uncontrolled asthma were also identified; higher levels were observed in uncontrolled asthma compared to controlled asthma (P <.05 for all). Asthmatics patients with higher levels of CD66+ neutrophils had lower FEV1(%), higher ACQ (but lower AQLO) scores, and higher sphingosine and C16:0 ceramide levels compared to those with low levels of CD66+ neutrophils. Asthmatics patients with higher levels of platelet‐adherent eosinophils had higher S1P levels compared to those with lower levels of platelet‐adherent eosinophils. Patients carrying TT genotype of ORMDL3 had more CD66+ neutrophils; those with AG/ GG genotypes of SGMS1 exhibited higher platelet‐adherent eosinophils. Conclusion: Patients with uncontrolled asthma possess distinct inflammatory phenotypes including increased CD66+ neutrophils and platelet‐adherent eosinophils, with an imbalanced ceramide/S1P rheostat, potentially involving ORMDL3 and SGMS1 gene polymorphisms. Ceramide/S1P synthesis could be targeted to control airway inflammation. [ABSTRACT FROM AUTHOR]