Abnormal liver phosphatidylcholine synthesis revealed in patients with acute respiratory distress syndrome

Abstract

Acute respiratory distress syndrome (ARDS) is associated with a severe pro-inflammatory response; although decreased plasma cholesterol concentration has been linked to systemic inflammation, any association of phospholipid metabolic pathways with ARDS has not been characterized. Plasma phosphatidylcholine (PC), the major phospholipid of circulating lipoproteins, is synthesized in human liver by two biologically diverse pathways: the CDP:choline and phosphatidylethanolamine-N-methyltransferase (PEMT) pathways. Here, we used electrospray ionization–MS/MS both to characterize plasma PC compositions and to quantify metabolic fluxes of both pathways using stable isotopes in patients with severe ARDS and in healthy controls. Direct incorporation of methyl-D9-choline estimated CDP:choline pathway flux, while PEMT flux was determined from incorporations of one and two methyl-D3 groups derived from methyl-D9-choline. Results of MS/MS analysis showed significant alterations in plasma PC composition in patients with ARDS versus healthy controls. In particular, the increased overall methyl-D9-PC enrichment and—most important—the much lower methyl-D3-PC and methyl-D6-PC enrichments—suggest increased flux through the CDP:choline pathway and reduced flux through the PEMT pathway in ARDS. To our knowledge, this study is the first to demonstrate significant plasma PC molecular compositional changes combined with associated alterations in the dynamics of PC synthetic pathways in patients with ARDS.

More information

Identifiers

ORCID for Anthony Postle: orcid.org/0000-0001-7361-0756

ORCID for Ahilanandan Dushianthan: orcid.org/0000-0002-0165-3359

ORCID for Rebecca Cusack: orcid.org/0000-0003-2863-2870

ORCID for Michael Grocott: orcid.org/0000-0002-9484-7581

Catalogue record

Export record

Altmetrics