Plasma Concentrations of Lysophosphatidic Acid and Autotaxin in Abstinent Patients with Alcohol Use Disorder and Comorbid Liver Disease

Exploratory study on plasma Acylglycerol and Acylethanolamide dysregulation in substance use and attention-deficit/hyperactivity disorder: Implications for novel biomarkers in dual diagnosis

Substance use disorder (SUD) is a major global public health challenge, frequently co-occurring with psychiatric conditions such as attention-deficit/hyperactivity disorder (ADHD). Endocannabinoid system (ECS) dysregulation has been implicated in both SUD and ADHD, but the interplay between these conditions remains poorly understood. This study investigates plasma concentrations of endocannabinoid-congeners in individuals with SUD, with and without comorbid ADHD, to identify potential biomarkers. This exploratory study included 469 participants divided into three groups: (1) healthy controls (n = 136), (2) patients with SUD without ADHD (n = 267), and (3) patients with SUD and comorbid ADHD (n = 66). Plasma concentrations of 12 endocannabinoid-related molecules, including acylglycerols (2-AG, 2-LG, 2-OG) and acylethanolamides (AEA, DEA, DHEA, DGLEA, LEA, OEA, PEA, POEA, and SEA), were quantified using high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS). A multinomial Elastic Net regression model was applied to assess their biomarker potential. Patients with SUD exhibited significantly lower plasma concentrations of 2-AG and 2-LG compared to controls, while most acylethanolamides were elevated, except for POEA and SEA. ADHD comorbidity was associated with lower concentrations of 2-AG, 2-LG, AEA, DGLEA, DHEA, and SEA, while PEA was elevated. Machine learning analysis identified AEA, OEA, PEA, and SEA as key biomarkers, achieving an accuracy of 72.1 % and an ROC-AUC of 0.77. This study suggests distinct ECS alterations in SUD and comorbid ADHD, highlighting endocannabinoid-congeners as potential biomarkers. Future research should validate these findings in larger cohorts and explore ECS-targeted therapeutic interventions for dual-diagnosis populations.

Serum Autotaxin Level Positively Associates with Metabolic-Associated Fatty Liver Disease and Hyperuricemia in Postmenopausal Women

INTRODUCTION

Autotaxin (ATX) is an adipokine known to affect energy metabolism and lipid homeostasis. We aimed to evaluate serum ATX levels in metabolic-associated fatty liver disease (MAFLD) and other metabolic disorders in postmenopausal women.

METHODS

Postmenopausal women who received an annual health examination were included. The metabolic and demographic characteristics of the subjects were collected, including age, gender, weight, height, blood pressure, and biochemical parameters. Serum ATX level was determined by ELISA.

RESULTS

This cross-sectional includes 20 postmenopausal women and 20 age-paired healthy controls. MAFLD patients showed significant metabolic disturbance presented with increased body mass index (BMI), blood pressure (p < 0.001) and decreased high-density lipoprotein cholesterol (p < 0.05), as well as liver injury companied by elevated ALT (p < 0.05). Serum ATX levels were statistically higher in MAFLD (253.1 ± 52.1 vs. 202.2 ± 53.2 ng/mL; p < 0.01) and positively correlated with ALT (p < 0.001), γ-glutamyltransferase and BMI (p < 0.01), SBP and TG (p < 0.05). Higher ATX group demonstrated worsen metabolic states with greater proportion of MAFLD, higher BMI (p < 0.01), and ALT (p < 0.05). Logistic regression analysis revealed that serum ATX levels would positively independently predicted MAFLD (OR 1.049, 95% CI: 1.001-1.098, p < 0.05) with AUC of 0.763. Serum level of ATX is significantly elevated in hyperuricemia group (257.3 ± 60.9 vs. 214.5 ± 49.4 ng/mL; p < 0.05) and positively correlated with uric acid level (p < 0.01). Serum ATX would also act as diagnosing parameter of hyperuricemia with AUC of 0.706.

CONCLUSIONS

Among postmenopausal women, serum ATX level is significantly elevated in MAFLD and related to multiple metabolic characteristics, especially hyperuricemia, which would thus serve as a potential noninvasive biomarker as well as a therapeutic target.

Bioactive signalling lipids as drivers of chronic liver diseases

Lipids are important in multiple cellular functions, with most having structural or energy storage roles. However, a small fraction of lipids exert bioactive roles through binding to G protein-coupled receptors and induce a plethora of processes including cell proliferation, differentiation, growth, migration, apoptosis, senescence and survival. Bioactive signalling lipids are potent modulators of metabolism and energy homeostasis, inflammation, tissue repair and malignant transformation. All these events are involved in the initiation and progression of chronic liver diseases. In this review, we focus specifically on the roles of bioactive lipids derived from phospholipids (lyso-phospholipids) and poly-unsaturated fatty acids (eicosanoids, pro-resolving lipid mediators and endocannabinoids) in prevalent chronic liver diseases (alcohol-associated liver disease, non-alcoholic fatty liver disease, viral hepatitis and hepatocellular carcinoma). We discuss the balance between pathogenic and beneficial bioactive lipids as well as potential therapeutic targets related to the agonism or antagonism of their receptors.

Plasma Lysophosphatidic Acid Concentrations in Sex Differences and Psychiatric Comorbidity in Patients with Cocaine Use Disorder

We have recently reported sex differences in the plasma concentrations of lysophosphatidic acid (LPA) and alterations in LPA species in patients with alcohol and cocaine use disorders. Preclinical evidence suggests a main role of lysophosphatidic acid (LPA) signaling in anxiogenic responses and drug addiction. To further explore the potential role of the LPA signaling system in sex differences and psychiatric comorbidity in cocaine use disorder (CUD), we conducted a cross-sectional study with 88 patients diagnosed with CUD in outpatient treatment and 60 healthy controls. Plasma concentrations of total LPA and LPA species (16:0, 18:0, 18:1, 18:2 and 20:4) were quantified and correlated with cortisol and tryptophan metabolites [tryptophan (TRP), serotonin (5-HT), kynurenine (KYN), quinolinic acid (QUIN) and kynurenic acid (KYNA)]. We found sexual dimorphism for the total LPA and most LPA species in the control and CUD groups. The total LPA and LPA species were not altered in CUD patients compared to the controls. There was a significant correlation between 18:2 LPA and age at CUD diagnosis (years) in the total sample, but total LPA, 16:0 LPA and 18:2 LPA correlated with age at onset of CUD in male patients. Women with CUD had more comorbid anxiety and eating disorders, whereas men had more cannabis use disorders. Total LPA, 18:0 LPA and 20:4 LPA were significantly decreased in CUD patients with anxiety disorders. Both 20:4 LPA and total LPA were significantly higher in women without anxiety disorders compared to men with and without anxiety disorders. Total LPA and 16:0 LPA were significantly decreased in CUD patients with childhood ADHD. Both 18:1 LPA and 20:4 LPA were significantly augmented in CUD patients with personality disorders. KYNA significantly correlated with total LPA, 16:0 LPA and 18:2 LPA species, while TRP correlated with the 18:1 LPA species. Our results demonstrate that LPA signaling is affected by sex and psychiatric comorbidity in CUD patients, playing an essential role in mediating their anxiety symptoms.

LPA1 receptors in the lateral habenula regulate negative affective states associated with alcohol withdrawal

The role of lysophosphatidic acid (LPA) signaling in psychiatric disorders and drug abuse is significant. LPA receptors are widely expressed in the central nervous system, including the lateral habenula (LHb). Recent studies suggest that LHb is involved in a negative emotional state during alcohol withdrawal, which can lead to relapse. The current study examines the role of LHb LPA signaling in the negative affective state associated with alcohol withdrawal. Adult male Long-Evans rats were trained to consume either alcohol or water for eight weeks. At 48 h of withdrawal, alcohol-drinking rats showed anxiety- and depression-like symptoms, along with a significant increase in LPA signaling and related neuronal activation molecules, including autotaxin (ATX, Enpp2), LPA receptor 1/3 (LPA1/3), βCaMKII, and c-Fos. However, there was a decrease in lipid phosphate phosphatase-related protein type 4 (LPPR4) in the LHb. Intra-LHb infusion of the LPA1/3 receptor antagonist ki-16425 or PKC-γ inhibitor Go-6983 reduced the abnormal behaviors and elevated relapse-like ethanol drinking. It also normalized high LPA1/3 receptors and enhanced AMPA GluA1 phosphorylation in Ser831 and GluA1/GluA2 ratio. Conversely, selective activation of LPA1/3 receptors by intra-LHb infusion of 18:1 LPA induced negative affective states and upregulated βCaMKII-AMPA receptor phosphorylation in Naive rats, which were reversed by pretreatment with intra-LHb Go-6983. Our findings suggest that disturbances in LPA signaling contribute to adverse affective disorders during alcohol withdrawal, likely through PKC-γ/βCaMKII-linked glutamate signaling. Targeting LPA may therefore be beneficial for individuals suffering from alcohol use disorders.

Plasma concentrations of lysophosphatidic acid and the expression of its receptors in peripheral blood mononuclear cells are altered in patients with cocaine use disorders

We have recently reported alterations in the plasma concentrations of lysophosphatidic acid (LPA) in patients with substance use disorders. In order to further explore the potential role of the LPA signaling system as biomarker in cocaine use disorders (CUD) we conducted a cross-sectional study with 105 patients diagnosed with CUD and 92 healthy controls. Participants were clinically evaluated and blood samples were collected to determine plasma concentrations of total LPA and LPA species (16:0-, 18:0-, 18:1-, 18:2-, and 20:4-LPA), and the gene expression of LPA1 and LPA2 receptors in peripheral blood mononuclear cells. We found that patients with CUD had significantly lower plasma concentration of the majority of LPA species, while the mRNA expression of LPA1 receptor was found to be higher than controls. Moreover, we found a positive association between plasma concentration of 20:4-LPA and relevant CUD-related variables: age of onset cocaine use and length of cocaine abstinence. The statistical analysis revealed sex differences in concentrations of total LPA and LPA species, and women showed higher LPA concentrations than men. Furthermore, studies in rats of both sexes showed that plasma concentrations of total LPA were also altered after acute and chronic cocaine administration, revealing a sexual dimorphism in these effects. This study found alterations on the LPA signaling system in both, patients with CUD and rats treated with cocaine. Our results demonstrate that LPA signaling is impacted by CUD and sex, which must be taken into consideration in future studies evaluating LPA as a reliable biomarker for CUD.

Plasma Amino Acid Concentrations in Patients with Alcohol and/or Cocaine Use Disorders and Their Association with Psychiatric Comorbidity and Sex

(1) Background: Co-occurrence of mental and substance use disorders (SUD) is prevalent, but complicates their clinical courses, and specific biomarkers are required. Amino acids are altered in primary mental disorders; however, little is known about SUD and psychiatric comorbidity. Because most psychiatric disorders and biomarkers show sex differences, we investigated amino acids in men and women with alcohol and/or cocaine use disorders (AUD and/or CUD) and psychiatric comorbidity. (2) Methods: A cross-sectional study was conducted in 295 participants, who were divided into four groups (AUD, n = 60; CUD, n = 41; AUD + CUD, n = 64; and control, n = 130). Participants were clinically assessed, and plasma amino acid concentrations were analyzed in relation to sex, diagnosis of SUD and psychiatric comorbidity (3) Results: In the total sample, there were sex differences, and women showed lower Iso, Leu, Gln and Glu than men. While patients with CUD and AUD + CUD had higher Glu, Gly, Orn and Ser than controls, patients with AUD showed no differences. In SUD, patients with psychiatric comorbidity had lower Orn and higher Ala than non-comorbid patients in the AUD group. (4) Conclusions: There was a dysregulation of plasma amino acids in abstinent patients with SUD. However, our results suggest the importance of considering the clinical characteristics and sex in the validity of amino acids as potential biomarkers for SUD.

Sex Differences in Plasma Lysophosphatidic Acid Species in Patients with Alcohol and Cocaine Use Disorders

Preclinical evidence suggests a main role of lysophosphatidic acid (LPA) signaling in drug addiction. Recently, we reported alterations in the plasma concentrations of LPA species in patients with alcohol use disorder (AUD). As there are sex differences in drug addiction, the main aim of the present study was to investigate whether relevant LPA species (16:0-LPA, 18:0-LPA, 18:1-LPA, 18:2-LPA and 20:4-LPA) were associated with sex and/or substance use disorder (SUD). This exploratory study was conducted in 214 abstinent patients with lifetime SUD, and 91 healthy control subjects. The SUD group was divided according to the diagnosis of AUD and/or cocaine use disorder (CUD). Participants were clinically assessed, and plasma samples were collected to determine LPA species and total LPA. We found that LPA concentrations were significantly affected by sex, and women showed higher concentrations than men. In addition, there were significantly lower 16:0-LPA, 18:2-LPA and total LPA concentrations in patients with SUD than in controls. Namely, patients with CUD and AUD + CUD showed lower LPA concentrations than controls or patients with AUD. In conclusion, our data suggest that LPA species could be potential biomarkers for SUD in women and men, which could contribute to a better stratification of these patients in treatment programs.