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A1617 - Pharmacometabolic Response to Pirfenidone Treatment in Pulmonary Fibrosis Detected by High Resolution MALDI FTICR-Mass Spectrometry Imaging
Author Block: I. E. Fernandez1, N. Sun2, M. Wei2, M. Witting3, M. Aichler2, S. Verleden4, P. Schmitt-Kopplin3, O. Eickelberg5, A. Walch2; 1Comprehensice Pneumology Center (CPC), Helmholtz Zentrum Muenchen, Munich, Germany, 2Research Unit Analytical Pathology, Helmholtz Zentrum Muenchen, Neuherberg, Germany, 3Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum Muenchen, Neuherberg, Germany, 4Leuven Lung Transplant Unit, KU Leuven, Leuven, Belgium, 5Pulmonary Sciences and Critical Care Medicine, Univ of Colorado Denver, Denver, CO, United States.
Rationale: Idiopathic pulmonary fibrosis is a fatal condition with limited life expectancy and response to available therapies. Pirfenidone has been approved for the treatment of IPF, but we know little about distinct metabolic changes in the lung upon pirfenidone treatment.
Methods: In this study, we used high resolution MALDI-FTICR-mass spectrometry (MS) to simultaneously detect, visualize, and quantify in situ endogenous and exogenous metabolites in lungs of mice and humans subjected to experimental fibrosis or with IPF, respectively, and assessed the effect of pirfenidone treatment on these levels. For that, we used bleomycin-induced pulmonary fibrotic mice,
treated with and without pirfenidone; and explanted tissue from non-disease, IPF and IPF patients under pirfenidone treatment at the moment of transplant.
Results: In total, 1402 molecules were found to be significant different between PBS and bleomycin-induced fibrosis tissue, with 409 molecules enriched and 993 molecules reduced in fibrotic regions. Furthermore, 536 of these molecules were annotated in METLIN database, putatively assigned to 57 lipids (24 reduced and 33 enriched in fibrotic regions), 234 peptides (223 reduced and 11 enriched in fibrotic regions), and 245 other metabolites. In IPF patients, 825 molecules were found to be significant different between the donor and fibrotic tissue, with 480 molecules enriched and 345 molecules reduced in IPF. The two central metabolic pathways with highest enrichment in fibrotic mice were: ascorbate and aldarate metabolism (p=0.0088024), amino sugar and nucleotide sugar metabolism (p=0.009716). Upon pirfenidone treatment in fibrotic mice, the most significantly downregulated pathway was ascorbate and aldarate metabolism (p=0.0004288). In IPF tissue, the two highest regulated pathways were: pentose and glucoronate interconversions (p=0.00015368), ascorbate and aldarate metabolism (p=0.0014891). Furthermore, metabolic pathway analysis and endogenous metabolite quantification revealed that pirfenidone treatment restored redox imbalance and glycolysis in IPF tissue, and downregulates ascorbate and aldarate metabolism, thereby likely contributing to in situ modulation of collagen processing. As such, we detected specific alterations of metabolite pathways in fibrosis, and most importantly, metabolic recalibration following pirfenidone treatment.
Conclusion: Taken together, these identified alterations in metabolites support the idea that metabolic profiles are transformed in regions affected by pulmonary fibrosis. Furthermore, here we highlight the suitability of high resolution MALDI-FTICR-MS to decipher therapeutic effects of pirfenidone and will help clarify disease mechanisms of pulmonary fibrosis that may contribute to improvement of currently available therapies for IPF.