Serum and Fecal Oxylipins in Patients with Alcohol-Related Liver Disease

Abstract

Background: Alcohol-related liver disease is one of the most prevalent chronic liver diseases worldwide. Mechanisms involved in the pathogenesis of alcohol-related liver disease are not well understood. Oxylipins play a crucial role in numerous biological processes and pathological conditions. Nevertheless, oxylipins are not well studied in alcohol-related liver disease.

Aims: (1) To characterize the patterns of bioactive ω-3 and ω-6 polyunsaturated fatty acid metabolites in alcohol use disorder and alcoholic hepatitis patients and (2) to identify associations of serum oxylipins with clinical parameters in patients with alcohol-related liver disease.

Methods: We performed a comprehensive liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis of serum and fecal oxylipins derived from ω-6 arachidonic acid, ω-3 eicosapentaenoic acid, and docosahexaenoic acid in a patient cohort with alcohol-related liver disease.

Results: Our results show profound alterations in the serum oxylipin profile of patients with alcohol use disorder and alcoholic hepatitis compared to nonalcoholic controls. Spearman correlation of the oxylipins with clinical parameters shows a link between different serum oxylipins and intestinal permeability, aspartate aminotransferase, bilirubin, albumin, international normalized ratio, platelet count, steatosis, fibrosis and model for end-stage liver disease score. Especially, higher level of serum 20-HETE was significantly associated with decreased albumin, increased hepatic steatosis, polymorphonuclear infiltration, and 90-day mortality.

Conclusions: Patients with alcohol-related liver disease have different oxylipin profiles. Future studies are required to confirm oxylipins as disease biomarker or to connect oxylipins to disease pathogenesis.

Keywords: AA; DHA; EPA; Lipid mediator; Metabolomics; PUFA.

Figure 1.

Oxylipins derived from arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. AA: arachidonic acid; EPA: eicosapentaenoic acid; DHA: docosahexaenoic acid; LOX: lipoxygenase; COX: cyclooxygenase; CYP: cytochrome p450; HpETE: hydroperoxyeicosatetraenoic acid; HETE: hydroxyeicosatetraenoic acid; DiHETE: dihydroxyeicosatetraenoic acid; PG: prostaglandin; TX: thromboxane X; EpETrE: epoxyeicosatrienoic acid; DiHETrE: dihydroxyeicosatrienoic acid; HpEPE: hydroperoxy-eicosapentaenoic acid; HEPE: hydroxyeicosapentaenoic acid; DiHEPE: dihydroxy-eicosapentaenoic acid; EpETE: epoxyeicosatetraenoic acid; HpDoHE: hydroperoxy-docosahexaenoic acid; HDoHE: hydroxydocosahexaenoic acid; DiHDoHE: dihydroxy-docosahexaenoic acid; DiHDPE: dihydroxy-docosapentaenoic acid

Figure 2.

Hierarchical clustering of serum oxylipins in control, alcohol use disorder and alcoholic hepatitis patients (A). *: adjusted p-value < 0.05. Partial least squares discriminant analysis of serum oxylipins (B). Important serum oxylipins identified by variable importance in projection scores (C). Ctrl: non-alcoholic control; AUD: alcohol use disorder; AH: alcoholic hepatitis.

Figure 3.

Hierarchical clustering of fecal oxylipins in controls, alcohol use disorder and alcoholic hepatitis patients (A). *: adjusted p-value < 0.05. Partial least squares discriminant analysis of fecal oxylipins (B). Important fecal oxylipins identified by variable importance in projection scores (C). Ctrl: non-alcoholic control; AUD: alcohol use disorder; AH: alcoholic hepatitis.

Figure 4.

ChemRICH analysis of serum oxylipins in alcoholic use disorder patients and controls (A). Ctrl: non-alcoholic control; AUD: alcohol use disorder; AH: alcoholic hepatitis. Significantly impacted metabolite clusters are shown in the plot (p < 0.05). The y-axis shows the most significantly altered clusters on the top. Red = increased in AUD patients. ChemRICH analysis of fecal oxylipins in alcoholic use disorder patients and controls (b). Ctrl nonalcoholic control; AUD alcohol use disorder; AH alcoholic hepatitis. Significantly impacted metabolite clusters are shown in the plot (p < 0.05). The y-axis shows the most significantly altered clusters on the top. Red=increased in AUD patients. Spearman correlation of serum oxylipins with intestinal permeability (C). Color intensity represents the correlation coefficient (R); Red: positive correlation; Blue: negative correlation. * p<0.05; ** p<0.01; *** p<0.001. Number of controls N=15; Number of AUD patients N=28. Spearman correlation of fecal oxylipins with intestinal permeability (D). Color intensity represents the correlation coefficient (R); Red: positive correlation; Blue: negative correlation. * p<0.05; ** p<0.01; *** p<0.001. Number of controls N=15; Number of AUD patients N=28.

Figure 5.

Spearman correlation of serum or fecal 4-HDoHE, 5-HETE, 5,6-DiHETrE with total gut permeability (A). Number of controls N=15; Number of alcoholic use disorder patients N=28. Total gut permeability was elevated in alcohol use disorder patients compared with control subjects (B). AUD: alcohol use disorder. Number of controls N=15; Number of alcoholic use disorder patients N=28. Serum levels of 4-HDoHE (C), 5-HETE (D), 5,6-DiHETrE (E) were increased in alcohol use disorder patients compared with controls. AUD: alcohol use disorder. Number of controls N=15; Number of alcoholic use disorder patients N=28.

Figure 6.

ChemRICH analysis of serum oxylipins in alcoholic hepatitis and alcohol use disorder patients (A). AUD: alcohol use disorder; AH: alcoholic hepatitis. Significantly impacted metabolite clusters are shown in the plot (p<0.05). The y-axis shows the most significantly altered clusters on the top. Red=increased in AH patients. Blue=decreased in AH patients. ChemRICH analysis of fecal oxylipins in alcoholic hepatitis and alcoholic use disorder (B). AUD: alcohol use disorder; AH: alcoholic hepatitis. Significantly impacted metabolite clusters were shown in the plot (p<0.05). The y-axis shows the most significantly altered clusters on the top. Red=increased in AH patients. Blue=decreased in AH patients. Purple=some increased compounds, others decreased in AH patients. Spearman correlation of serum oxylipins with laboratory parameters in alcohol use disorder and alcoholic hepatitis patients (c). Color intensity represents the correlation coefficient (R); Red: positive correlation. Blue: negative correlation. * p<0.05, ** p<0.01, *** p<0.001. INR, international normalized ratio; ALT, alanine aminotransferase; AST, aspartate aminotransferase; GGT, gamma-glutamyl-transferase; AP, alkaline phosphatase.

Figure 7.

Spearman correlation of serum oxylipins with parameters of liver disease stage in alcohol use disorder patients (A). CAP: controlled attenuation parameter. Color intensity represents the correlation coefficient (R); Red: positive correlation. Blue: negative correlation. * p<0.05. Number of alcohol use disorder patients N=30. Spearman correlation of serum oxylipins with liver histology and clinical scores in alcoholic hepatitis patients (B). Color intensity represents the correlation coefficient (R); Red: positive correlation. Blue: negative correlation. * p<0.05, ** p<0.01, *** p<0.001. MELD: model for end-stage liver disease; MELDNa: sodium model for end-stage liver disease. Number of alcoholic hepatitis patients N=7.