Genetic markers in the EET metabolic pathway are associated with outcomes in patients with aneurysmal subarachnoid hemorrhage

Abstract

Preclinical studies show that epoxyeicosatrienoic acids (EETs) regulate cerebrovascular tone and protect against cerebral ischemia. We investigated the relationship between polymorphic genes involved in EET biosynthesis/metabolism, cytochrome P450 (CYP) eicosanoid levels, and outcomes in 363 patients with aneurysmal subarachnoid hemorrhage (aSAH). Epoxyeicosatrienoic acids and dihydroxyeicosatetraenoic acid (DHET) cerebrospinal fluid (CSF) levels, as well as acute outcomes defined by delayed cerebral ischemia (DCI) or clinical neurologic deterioration (CND), were assessed over 14 days. Long-term outcomes were defined by Modified Rankin Scale (MRS) at 3 and 12 months. CYP2C8*4 allele carriers had 44% and 36% lower mean EET and DHET CSF levels (P=0.003 and P=0.007) and were 2.2- and 2.5-fold more likely to develop DCI and CND (P=0.039 and P=0.041), respectively. EPHX2 55Arg, CYP2J2*7, CYP2C8*1B, and CYP2C8 g.36785A allele carriers had lower EET and DHET CSF levels. CYP2C8 g.25369T and CYP2C8 g.36755A allele carriers had higher EET levels. Patients with CYP2C8*2C and EPHX2 404del variants had worse long-term outcomes while those with EPHX2 287Gln, CYP2J2*7, and CYP2C9 g.816G variants had favorable outcomes. Epoxyeicosatrienoic acid levels were associated with Fisher grade and unfavorable 3-month outcomes. Dihydroxyeicosatetraenoic acids were not associated with outcomes. No associations passed Bonferroni multiple testing correction. These are the first clinical data demonstrating the association between the EET biosynthesis/metabolic pathway and the pathophysiology of aSAH.

Figure 1

Cytochrome P450 (CYP) eicosanoid levels in genetic groups. Mean epoxyeicosatrienoic acid (EET) (A), maximum EET (B), mean dihydroxyeicosatetraenoic acid (DHET) (C), and maximum DHET (D) levels in cerebrospinal fluid (CSF) from patients with aneurysmal subarachnoid hemorrhage (aSAH) are compared in genotype groups. The mean and maximum EET and DHET CSF levels for each patient were calculated and were used to compare the mean±s.e.m. of the CYP eicosanoid levels for each patient in the variant allele carrier (striped bars) and wild-type (WT) genotype (solid bars) groups using t-test with Welch's correction as appropriate. Genotype groups were compared using ANOVA in Supplementary Figure 1. Statistical significance established at *P<0.05.

Figure 2

Cytochrome P450 (CYP) eicosanoid levels in outcome groups. Mean epoxyeicosatrienoic acid (EET) (A), maximum EET (B), mean dihydroxyeicosatetraenoic acid (DHET) (C), and maximum DHET (D) levels in cerebrospinal fluid (CSF) from patients with aneurysmal subarachnoid hemorrhage (aSAH) are compared in outcomes groups. Acute outcomes (solid bars) included the presence or absence of delayed cerebral ischemia (DCI) and clinical neurologic deterioration (CND) up to 14 days after the hemorrhage. Long-term outcomes (stripped bars) were determined by global functional recovery at 3 and 12 months using the Modified Rankin Scale (MRS) and were dichotomized into favorable (MRS 0 to 2) and unfavorable (MRS 3 to 6) groups. The mean and maximum EET and DHET CSF levels for each patient were calculated and were used to compare the mean±s.e.m. of the CYP eicosanoid levels in outcome groups using t-test with Welch's correction as appropriate. Statistical significance established at *P<0.05.

Figure 3

Cytochrome P450 (CYP) eicosanoid temporal concentration profiles and trajectory patterns. (A) Raw population values of dihydroxyeicosatetraenoic acid (DHET) cerebrospinal fluid (CSF) concentrations (ng/mL) from 269 patients up to 14 days after hemorrhage are shown. (B) DHET CSF concentration versus time from hemorrhage (days) in high (filled circles, n=65 (24.2%)), moderate (open circles, n=159 (59.1%)), and low (X, n=45 (16.7%)) concentration groups as identified by trajectory analysis is shown. Concentration data are presented as geometric mean with 95% confidence interval.