A reverse translational study of PPAR-α agonist efficacy in human and rodent models relevant to alcohol use disorder

Alcohol Use Disorder (AUD) is a chronic relapsing disorder affecting an estimated 283 million individuals worldwide, with substantial health and economic consequences. Peroxisome proliferator-activated receptors (PPARs), particularly PPAR-α and PPAR-γ, have shown promise in preclinical studies as potential therapeutic targets for AUD. In this human laboratory study, we aimed to translate preclinical findings on the PPAR-α agonist fenofibrate to a human population with current AUD. We hypothesized that, relative to placebo, fenofibrate at the highest FDA-approved dose of 145 mg/d would attenuate responsiveness to in vivo alcohol cues in the lab and reduce drinking under natural conditions. However, the results did not show significant differences in craving and alcohol consumption between the fenofibrate and placebo groups. Reverse translational studies in rodent models confirmed the lack of fenofibrate effect at human-equivalent doses. These findings suggest that inadequate translation of drug dose from rodents to humans may account for the lack of fenofibrate effects on alcohol craving and consumption in humans with AUD. The results highlight the need for new brain-penetrant PPAR-α agonists to adequately test the therapeutic potential of PPAR-α agonists for AUD, and the importance of reverse translational approaches and selection of human-equivalent doses in drug development.

Psychosocial and psychiatric-related stress and cigarette smoking among Black and Latinx adults with psychiatric disorders

While the cigarette smoking prevalence in the United States has decreased, smoking disparities persist for individuals with psychiatric disorders and individuals who identify as racial/ethnic minorities. These groups also experience higher levels of psychosocial stress. This study was the first to examine the relationship between psychosocial and psychiatric-related stressors and cigarette smoking status in a sample of Black and Latinx adults with psychiatric illness. Stress associated with friend strain, lifetime discrimination, and attending appointments for psychotropic medication management were associated with cigarette smoking. The present results have implications for integrating smoking cessation interventions into mental health treatment settings.

Relationship of trauma exposure and PTSD to cigarette smoking prevalence, frequency, and quantity: Data from a nationally representative sample of U.S. adults

Individuals with Post-Traumatic Stress Disorder (PTSD) smoke cigarettes at much higher prevalences than the general population. Less is known about PTSD and other smoking behaviors (e.g., smoking quantity and frequency) or about smoking among individuals who experience trauma.

OBJECTIVE

To examine differences in cigarette smoking behaviors among adults in the United States (a) with no exposure to trauma or PTSD, (b) with trauma but no PTSD, and (c) with PTSD.

METHODS

Data came from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions-II (NESARC-II, 2004-2005) and included demographics, PTSD diagnoses, traumatic events, and smoking behaviors. Odds ratios and group differences in smoking prevalence and behaviors based on PTSD diagnoses and exposure to traumatic experiences were calculated.

RESULTS

Traumatic events and PTSD diagnoses were both associated with greater smoking prevalences than persons without trauma or PTSD. Individuals with PTSD who smoke were more likely to report daily smoking than those without PTSD who smoke (Cohen's d = 0.19). Cigarette users with either trauma or PTSD smoked more cigarettes per day than cigarette users without trauma or PTSD (Cohen's d = 0.35). US adults with trauma exposure or PTSD have higher smoking prevalences and more intense smoking behaviors than those without PTSD or trauma.

CONCLUSION

Trauma or PTSD may each serve as a clinical indicator of increased risk of cigarette smoking-related health problems and prompt the implementation of targeted interventions to reduce the harms of smoking. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Glucocorticoid receptor antagonism decreases alcohol seeking in alcohol-dependent individuals

Alcoholism, or alcohol use disorder, is a major public health concern that is a considerable risk factor for morbidity and disability; therefore, effective treatments are urgently needed. Here, we demonstrated that the glucocorticoid receptor (GR) antagonist mifepristone reduces alcohol intake in alcohol-dependent rats but not in nondependent animals. Both systemic delivery and direct administration into the central nucleus of the amygdala, a critical stress-related brain region, were sufficient to reduce alcohol consumption in dependent animals. We also tested the use of mifepristone in 56 alcohol-dependent human subjects as part of a double-blind clinical and laboratory-based study. Relative to placebo, individuals who received mifepristone (600 mg daily taken orally for 1 week) exhibited a substantial reduction in alcohol-cued craving in the laboratory, and naturalistic measures revealed reduced alcohol consumption during the 1-week treatment phase and 1-week post-treatment phase in mifepristone-treated individuals. Mifepristone was well tolerated and improved liver-function markers. Together, these results support further exploration of GR antagonism via mifepristone as a therapeutic strategy for alcoholism.

Role of Tet1 and 5-hydroxymethylcytosine in cocaine action

Ten-eleven translocation (TET) enzymes mediate the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), which is enriched in brain, and its ultimate DNA demethylation. However, the influence of TET and 5hmC on gene transcription in brain remains elusive. We found that ten-eleven translocation protein 1 (TET1) was downregulated in mouse nucleus accumbens (NAc), a key brain reward structure, by repeated cocaine administration, which enhanced behavioral responses to cocaine. We then identified 5hmC induction in putative enhancers and coding regions of genes that have pivotal roles in drug addiction. Such induction of 5hmC, which occurred similarly following TET1 knockdown alone, correlated with increased expression of these genes as well as with their alternative splicing in response to cocaine administration. In addition, 5hmC alterations at certain loci persisted for at least 1 month after cocaine exposure. Together, these reveal a previously unknown epigenetic mechanism of cocaine action and provide new insight into how 5hmC regulates transcription in brain in vivo.