The polyunsaturated fatty acid and oxylipin plasma signature of aneurysmal subarachnoid haemorrhage, case-control study.

Delayed cerebral ischemia (DCI) following aneurysmal subarachnoid haemorrhage (aSAH) is a complex and acute condition with limited options for early detection and effective treatments. The plasma levels of individual polyunsaturated fatty acids (PUFA) and their bioactive metabolites (oxylipins) of aSAH patients both at admission and over time remain largely unexplored, particularly concerning the development of DCI. In this study, plasma samples of aSAH patients were collected at admission and on days 4, 10, and 21 post-admission. ASAH patients who did not develop DCI were age- and sex matched to aSAH patients who did develop DCI. Control groups included patients with an unruptured aneurysm (UA) and healthy controls (HC). PUFA and oxylipin levels in plasma were measured using liquid chromatography with tandem mass spectrometry and were analysed using non-parametric univariate tests. At admission, aSAH (n ​= ​47) patients showed elevated levels of several PUFAs, such as linoleic acid and arachidonic acid, as well as oxylipins, including 12-HETE, 20-HETE and 19,20-DiHDPA, compared to UA (n ​= ​24) and HC (n ​= ​13). 12-HETE was predominantly found in the S-configuration, indicating synthesis via 12(S)-lipoxygenase. PUFA and oxylipin levels dropped significantly by day four post-admission, except for 19,20-DiHDPA. No PUFAs or oxylipins differentiated patients who developed DCI. We characterized a distinct plasma PUFA- and oxylipin profile in aSAH patients at admission and identified a significant decline in PUFA and oxylipin levels by day 4 post-admission.