John B. Trudeau

Learn More
The mechanisms associated with the development of severe, corticosteroid (CS)-dependent asthma are poorly understood, but likely heterogenous. It was hypothesized that severe asthma could be divided pathologically into two inflammatory groups based on the presence or absence of eosinophils, and that the inflammatory subtype would be associated with distinct(More)
BACKGROUND Asthma is a heterogeneous process, yet little is understood regarding phenotypes. OBJECTIVE To determine whether phenotypic differences exist between early-onset, severe asthma as compared with late-onset disease and whether the presence or absence of eosinophilia influences the phenotypes. METHODS Cross-sectional analysis of integrated(More)
To investigate the contribution of leukotrienes (LTs) to inflammation and bronchoconstriction in nocturnal asthma, we performed a randomized trial in 12 asthmatic patients and 6 normal control subjects. This study involved pulmonary function testing, methacholine challenge, bronchoscopy for cell counts, LT and thromboxane (TX) levels in bronchoalveolar(More)
The transforming growth factor (TGF)-beta family is important for tissue repair in pathological conditions including asthma. However, little is known about the impact of either TGF-beta1 or TGF-beta2 on asthmatic airway epithelial mucin expression. We evaluated bronchial epithelial TGF-beta1 and TGF-beta2 expression and their effects on mucin expression,(More)
BACKGROUND Although 15(S)-hydroxyeicosatetraenoic acid (15(S)-HETE), a product of 15-lipoxygenase (15-LO), may be involved in mild to moderate asthma, little is known about its potential roles in severe asthma. OBJECTIVES This study was performed to evaluate 15(S)-HETE levels in bronchoalveolar lavage fluid (BALF) from severe asthmatics with and without(More)
Chronic diseases may involve an "innate" response followed by an adaptive immune response, of a Th1 or Th2 variety. Little is known regarding the interactions of these responses. We hypothesized that TGF-beta1 (innate response factor associated with wound repair) in combination with IL-13 (Th2 factor) might augment inflammatory processes associated with(More)
BACKGROUND TGF-beta induces expression of tissue inhibitor of metalloproteinase 1 (TIMP-1), a potent inhibitor of matrix metalloproteinases that controls extracellular matrix metabolism and deposition. IL-13 alone does not induce TIMP-1, but in combination with TGF-beta it augments TIMP-1 expression. Although these interactions have implications for(More)
BACKGROUND Airway remodeling may play an important role in asthma pathophysiology. Transforming growth factor beta (TGF-beta) has a critical role in the remodeling process. Although cellular sources for TGF-beta have been previously investigated in asthma airways, the expression, release, or both of TGF-beta from asthmatic airways and blood neutrophils has(More)
BACKGROUND Exhaled nitric oxide is increased in asthma, but the mechanisms controlling its production, including the effects of T-helper type 2 (Th2) cytokines, are poorly understood. In mouse and submerged human epithelial cells, Th2 cytokines inhibit expression of inducible nitric oxide synthase (iNOS). Arginases have been proposed to contribute to asthma(More)
Epithelial 15-lipoxygenase 1 (15LO1) and activated ERK are increased in asthma despite modest elevations in IL-13. MAPK kinase (MEK)/ERK activation is regulated by interactions of Raf-1 with phosphatidylethanolamine-binding protein 1 (PEBP1). Epithelial 15LO1 generates intracellular 15-hydroxyeicosatetraenoic acid (15HETE) conjugated to(More)