Blood endocannabinoid levels in patients with panic disorder

Endocannabinoids and Stress-Related Neurospsychiatric Disorders: A Systematic Review and Meta-Analysis of Basal Concentrations and Response to Acute Psychosocial Stress

Background: Dysregulation of the endocannabinoid (eCB) system is implicated in various stress-related neuropsychiatric disorders (SRDs), including anxiety, depression, and post-traumatic stress disorder (PTSD). In this systematic review and meta-analysis, our objectives were to characterize circulating anandamide (AEA) and 2-arachidonoylglycerol (2-AG) concentrations at rest and in response to acute laboratory-based psychosocial stress in individuals with SRDs and without (controls). Our primary aims were to assess the effects of acute psychosocial stress on eCB concentrations in controls (Aim 1), compare baseline (prestress) eCB concentrations between individuals with SRDs and controls (Aim 2), and explore differential eCB responses to acute psychosocial stress in individuals with SRDs compared with controls (Aim 3). Methods: On June 8, 2023, a comprehensive review of the MEDLINE (PubMed) database was conducted to identify original articles meeting inclusion criteria. A total of 1072, 1341, and 400 articles were screened for inclusion in Aims 1, 2, and 3, respectively. Results: Aim 1, comprised of seven studies in controls, revealed that most studies reported stress-related increases in AEA (86%, with 43% reporting statistical significance) and 2-AG (83%, though none were statistically significant except for one study in saliva). However, meta-analyses did not support these patterns (p's>0.05). Aim 2, with 20 studies, revealed that most studies reported higher baseline concentrations of both AEA (63%, with 16% reporting statistical significance) and 2-AG (60%, with 10% reporting statistical significance) in individuals with SRDs compared with controls. Meta-analyses confirmed these findings (p's<0.05). Aim 3, which included three studies, had only one study that reported statistically different stress-related changes in 2-AG (but not AEA) between individuals with PTSD (decrease) and controls (increase), which was supported by the meta-analysis (p<0.001). Meta-analyses showed heterogeneity across studies and aims (I2=14-97%). Conclusion: Despite substantial heterogeneity in study characteristics, samples, and methodologies, consistent patterns emerged, including elevated baseline AEA and 2-AG in individuals with SRDs compared with controls, as well as smaller stress-related increases in 2-AG in individuals with SRDs compared with controls. To consider eCBs as reliable biomarkers and potential intervention targets for SRDs, standardized research approaches are needed to clarify the complex relationships between eCBs, SRDs, and psychosocial stress.

Alterations in plasma endocannabinoid concentrations among individuals with major depression treated with electroconvulsive therapy

The role of the endocannabinoid system (ECS) in depression and suicidality has recently emerged. The purpose of the study was to identify changes in plasma endocannabinoid concentrations of several endocannabinoids and correlate them with depressive symptoms and suicidality in patients with severe major depression undergoing electroconvulsive therapy (ECT). The study included 17 patients that were evaluated in four visits at different stages of therapy. At each visit depression, anxiety and suicidality symptoms were assessed and blood samples collected. Several endocannabinoid concentrations increased following six sessions of ECT, as 2-AG (p < 0.05) and LEA (p < 0.01), and following twelve sessions of ECT, as 2-AG (p < 0.05), AEA (p < 0.05), LEA (p < 0.05) and DH-Gly (p < 0.05). Endocannabinoids also correlated with symptoms of depression, anxiety and suicidality at baseline and at the sixth ECT session. Finally, we found one endocannabinoid, l-Gly, that differentiated between remitted and not-remitted patients at the seventh and thirteenth ECT sessions (p < 0.05). Our findings suggest that depression is markedly related to imbalance of the endocannabinoid system, and further regulated by ECT. Plasma endocannabinoids could be promising biomarkers for detection of depression response and remission.

Lipids and lipid signaling molecules in human milk and infant formula, a chemical characterization of relevant biochemical components

Breastfeeding is the gold standard in infant nutrition and continuous researches aim to optimize infant formula composition as the best alternative available. Human milk lipid content provides more than 50% of energy requirements for infants together with essential vitamins, polyunsaturated fatty acids, and other bioactive components. While fatty acids and vitamins human milk content has been extensively studied and, when needed those have been added to infant formulas, less is known about polyunsaturated fatty acids functional derivatives and other bioactive components. Here we describe the comparison of lipid compositions in breast milk from 22 healthy volunteers breastfeeding mothers and the six most common infant formula devoting particular attention to two families of signaling lipids, endocannabinoids, and eicosanoids. The main differences between breast milk and formulas lie in a variety of saturated fatty and unsaturated fatty acids, in the total amount (45-95% less in infant formula) and a variety of endocannabinoids and eicosanoids (2-AG, 5(s)HETE, 15(S)-HETE and 14,15-EET).

Endocannabinoid and perceived stress: Association analysis of endocannabinoid levels in hair versus levels in plasma and urine

The endocannabinoid system is considered to play a role in a wide range of functions, including stress. Hair analysis of endocannabinoids presents a promising methodological advancement for the retrospective assessment of long-term cumulative endocannabinoid secretion. Despite promising pilot study results suggesting the usefulness of hair endocannabinoid assessments, it remains unclear whether hair endocannabinoid levels mirror systemic endocannabinoid levels accurately. Two independent studies were conducted to investigate to what extent hair endocannabinoid and N-Acylethanolamine levels reflect the systemic levels retrospectively. Endocannabinoid and N-Acylethanolamine levels were measured in 3 cm and 1 cm hair segments respectively, and compared with the averaged levels in multiple plasma samples collected during three months (Study I), and in multiple 24-hour urine samples collected over a month (Study II). In addition, the Perceived Stress Scale was used to assess the perceived stress throughout the studies. Against our hypothesis, no association was found between the endocannabinoid or N-Acylethanolamine levels in hair and plasma or urine. However, hair palmitoylethanolamide (PEA), oleoylethanolamide (OEA), and stearoylethanolamide (SEA) levels were positively correlated with perceived stress in Study I. The current findings suggest that hair endocannabinoid or N-Acylethanolamine levels might not accurately reflect the levels of peripheral circulating endocannabinoid or N-Acylethanolamine. Nevertheless, hair N-Acylethanolamine levels might emerge as a useful strategy in the study of some psychological phenotypes, such as stress.

The Role of the Endocannabinoids 2-AG and Anandamide in Clinical Symptoms and Treatment Outcome in Veterans with PTSD

BACKGROUND

Although current treatments for Post-Traumatic Stress Disorder (PTSD) in war veterans are effective, unfortunately 30-50% still do not benefit from these treatments. Trauma-focused therapies, eg exposure therapy, are primarily based on extinction processes in which the endocannabinoid system (ECS) plays a significant role. Therefore, it can be hypothesized that poor treatment response on trauma-focused therapy due to extinction deficits may be associated with a poorly functioning ECS. The present study examined whether the endocannabinoids anandamide (AEA) and 2-arachidonylglycerol (2-AG) are associated with post-treatment symptom reduction.

METHODS

Blood plasma levels of AEA and 2-AG were determined in war veterans with a PTSD diagnosis (n = 54) and combat controls (n = 26) before and after a 6-8 month interval. During this period veterans with PTSD received trauma-focused therapy (eg cognitive behavioral therapy with exposure or eye-movement desensitization and reprocessing). Clinical symptoms were assessed before and after therapy with the Clinician Administered PTSD Scale (CAPS), State-Trait Anxiety Inventory (STAI) and Mood and Anxiety Symptom Questionnaire (MASQ).

RESULTS

Regression analysis demonstrated that pretreatment endocannabinoid levels were not predictive of PTSD symptom reduction. Additionally, baseline endocannabinoid levels did not differ between either PTSD and combat controls or between combat controls, treatment responders, and non-responders. Only cortisol levels significantly decreased over time from pre- to posttreatment (p = .041). Endocannabinoid levels were significantly lower in individuals who reported cannabis use during their lifetime, independent of PTSD diagnosis. Furthermore, correlation analysis revealed that pretreatment 2-AG levels in PTSD were positively correlated with anxious arousal (r = .354, p = .015) and negatively with avoidance symptoms (r = -.271, p = .048). Both posttreatment AEA and 2-AG were positively correlated with trait anxiety (AEA r = .459, p = .003; 2-AG r = .423, p = .006), anxious arousal (AEA r = .351, p = .024; 2-AG r = .311, p = .048) and general distress depression symptoms (AEA r = .414, p = .007; 2-AG r = .374, p = .016).

CONCLUSION

Since endocannabinoids are mainly generated 'on demand', future work could benefit by investigating endocannabinoid circulation under both baseline and stressful conditions. In line with previous research cannabis use was associated with lower endocannabinoid levels. The correlation analysis between pre- and posttreatment endocannabinoid levels and pre- and posttreatment clinical symptomatology were exploratory analysis and should be replicated in future research.

Intra-individual stability of hair endocannabinoid and N-acylethanolamine concentrations

Hair analysis of endocannabinoids and N-acylethanolamines presents a promising methodological advancement for the retrospective assessment of long-term cumulative endocannabinoids and N-acylethanolamines secretion over extended periods of time. A main assumption of this method application that hair endocannabinoid and N-acylethanolamine concentrations show intra-individual stability has not been confirmed yet. Thus, in the current study hair endocannabinoid and N-acylethanolamine levels were measured over a period of two and a half years with six months between each hair sample collection in 100 female participants. We found strong test-retest associations of hair endocannabinoid and N-acylethanolamine levels with intraclass correlation coefficients between 0.79 and 0.92. Furthermore, no correlations between perceived stress and hair endocannabinoids or N-acylethanolamines was observed. The current findings support the notion that endocannabinoids and N-acylethanolamines in hair are rather trait biomarkers that are stable over a considerable period of time rather than rapidly changing state markers.