Soluble Epoxide Hydrolase Is Associated with Postprandial Anxiety Decrease in Healthy Adult Women

Abstract

The metabolism of bioactive oxylipins by soluble epoxide hydrolase (sEH) plays an important role in inflammation, and sEH may be a risk modifier in various human diseases and disorders. The relationships that sEH has with the risk factors of these diseases remain elusive. Herein, sEH protein expression and activity in white blood cells were characterized before and after a high-fat meal in healthy women (HW) and women with anorexia nervosa (AN). sEH expression and sEH activity were significantly correlated and increased in both groups two hours after consumption of the study meal. Fasting sEH expression and activity were positively associated with body mass index (BMI) in both groups, while an inverse association with age was found in AN only (p value < 0.05). sEH was not associated with anxiety or depression in either group at the fasting timepoint. While the anxiety score decreased after eating in both groups, a higher fasting sEH was associated with a lower postprandial anxiety decrease in HW (p value < 0.05). sEH characterization using direct measurements verified the relationship between the protein expression and in vivo activity of this important oxylipin modulator, while a well-controlled food challenge study design using HW and a clinical control group of women with disordered eating elucidated sEH’s role in the health of adult women.

Keywords: anxiety; healthy adults; metabolism; soluble epoxide hydrolase.

Figure 1

Pearson’s correlations between soluble epoxide hydrolase (sEH) expression and sEH activity in healthy women (blue) and women with AN (red) at (A) fasting and (B) postprandial timepoints. Colored dots and solid lines represent individual data points and slopes of the examined relationships, respectively. r and p indicate Pearson’s correlation coefficient and p value, respectively. HW: healthy women; AN: anorexia nervosa.

Figure 2

Distribution of (A) sEH expression and (B) sEH activity in healthy women and women with anorexia nervosa at fasting (purple) and postprandial (green) timepoints. Diamonds and colored dots represent means and individual data points, respectively. Boxplots indicate the 25th percentile, median, and 75th percentile. HW: healthy women; AN: anorexia nervosa.

Figure 3

Bar plots of postprandial changes (%) in sEH expression and sEH activity in (A) healthy women and (B) women with anorexia nervosa at 2-h after consumption of the study meal. Bars and error bars represent the mean and standard error of the mean, respectively. p represents the p value of one-sample t-test for each study group, separately. HW: healthy women; AN: anorexia nervosa.

Figure 4

Polygonal graph summarizing mean sEH levels at fasting and postprandial timepoints and mean postprandial sEH changes (%) in healthy women (blue) and women with anorexia nervosa (pink). HW: healthy women; AN: anorexia nervosa.

Figure 5

Scatterplots for Pearson’s correlations of (A,B) fasting sEH expression and (C,D) sEH activity with age and BMI in healthy women (blue) and women with anorexia nervosa (red). Colored dots and solid lines represent individual data points and slopes of the examined relationships, respectively. r and p indicate Pearson’s correlation coefficient and p value, respectively. HW: healthy women; AN: anorexia nervosa; BMI: body mass index; NS: non-significant, p value ≥ 0.10.

Figure 6

Bar plots for anxiety level at fasting (purple) and postprandial (green) timepoints in HW and AN.

Figure 7

Scatterplots for Pearson’s correlations of sEH expression (top) and activity (bottom) with Beck Anxiety Score at (A) fasting and (B) postprandial timepoints in healthy women (blue) and women with anorexia nervosa (red). Scatterplots for Pearson’s correlations of sEH expression (top) and activity (bottom) with postprandial unit change in Beck Anxiety Score are presented in (C). Colored dots and solid lines represent individual data points and slopes of the examined relationships, respectively. r and p indicate Pearson’s correlation coefficient and p value, respectively. HW: healthy women; AN: anorexia nervosa; NS: non-significant, p value ≥ 0.10.