Effect of detoxification on N3 sleep correlates with brain functional but not structural changes in alcohol use disorder

BACKGROUND

Sleep disturbances are very common in alcohol use disorder (AUD) and contribute to relapse. Detoxification appears to have limited effects on sleep problems. However, inter-individual differences and related brain mechanisms have not been closely examined.

METHODS

We examined N3 sleep and the associated brain functional and structural changes in 30 AUD patients (9 Females, mean age: 42 years) undergoing a 3-week inpatient detoxification. Patients' N3 sleep, resting state functional connectivity (RSFC), grey matter volume (GMV) and negative mood were measured on week 1 and week 3.

RESULTS

AUD patients did not show significant N3 sleep recovery after 3-weeks of detoxification. However, we observed large variability among AUD patients. Inter-individual variations in N3 increases were associated with increases in midline default mode network (DMN) RSFC but not with GMV using a whole-brain approach. Exploratory analyses revealed significant sex by detoxification effects on N3 sleep such that AUD females showed greater N3 increases than AUD males. Further, N3 increases fully mediated the effect of mood improvement on DMN RSFC increases.

CONCLUSIONS

We show a significant relationship between N3 and DMN functional changes in AUD over time/abstinence. The current findings may have clinical implications for monitoring brain recovery in AUD using daily sleep measures, which might help guide individualized treatments. Future investigations on sex differences with a larger sample and with longitudinal data for a longer period of abstinence are needed.

Sex differences in weight gain during medication-based treatment for opioid use disorder: A meta-analysis and retrospective analysis of clinical trial data

BACKGROUND

Side effects of medications for opioid use disorder (MOUD) such as weight gain contribute to their stigma. Substantial evidence suggests that women have a more severe side effect profile to MOUD than men, and concerns about weight gain during treatment are prevalent. However, the few studies reporting sex differences in weight gain during treatment show conflicting results and are restricted to methadone. In addition, little is known about possible sex differences in weight gain to buprenorphine, which is the most commonly prescribed MOUD in the United States.

METHODS

To address these issues, we performed a systematic review and meta-analysis on the few studies reporting longitudinal data on sex differences in body mass index (BMI) gain during methadone treatment (Study 1). In a separate study, we also re-analyzed data from trial CTN-0030 of the National Institute on Drug Abuse Clinical Trial Network (NIDA CTN), which involved a 12-week buprenorphine treatment regimen (Study 2; n = 360; 209 Male, 151 Female).

RESULTS

For Study 1, across all papers reporting longitudinal data (k = 4, n = 362 OUD patients), there were BMI increases that ranged from 2.2 to 5.4 BMI after at least one year of methadone treatment, but there were no significant sex differences in BMI increases (Standardized Mean Difference, Female > Male = 0.352, SE =0.270; 95 % CI = [-0.18 0.88]; p = .193). Study 2 showed no significant differences in weight before and after 12 weeks of buprenorphine treatment nor did it show sex differences in weight change with treatment (β = 2.34, p = .511).

CONCLUSION

These analyses corroborate evidence of weight gain with methadone treatment but did not observe a sex-based disparity in weight gain with methadone or buprenorphine treatment for OUD.

Elevated transferrin saturation in individuals with alcohol use disorder: Association with HFE polymorphism and alcohol withdrawal severity

Iron loading has been consistently reported in those with alcohol use disorder (AUD), but its effect on the clinical course of the disease is not yet fully understood. Here, we conducted a cohort study to examine whether peripheral iron measures, genetic variation in HFE rs1799945 and their interaction differed between 594 inpatient participants with alcohol use disorder (AUD) undergoing detoxification and 472 healthy controls (HC). We also assessed whether HFE rs1799945 was associated with elevated peripheral iron and can serve as a predictor of withdrawal severity. AUD patients showed significantly higher serum transferrin saturation than HC. Within the AUD group, transferrin saturation significantly predicted withdrawal symptoms (CIWA-Ar) and cumulative dose of benzodiazepine treatment during the first week of detoxification, which is an indicator of withdrawal severity. HFE rs1799945 minor allele carriers showed elevated transferrin saturation compared to non-carriers, both in AUD and healthy controls. Exploratory analyses indicated that, within the AUD cohort, HFE rs1799945 predicted CIWA withdrawal scores, and this relationship was significantly mediated by transferrin saturation. We provide evidence that serum transferrin saturation predicts alcohol withdrawal severity in AUD. Moreover, our findings replicated previous studies on elevated serum transferrin saturation in AUD and an involvement of HFE rs1799945 in serum transferrin saturation levels in both AUD and healthy controls. Future studies may use transferrin saturation measures as predictors for treatment or potentially treat iron overload to ameliorate withdrawal symptoms.

Dopamine D1 and D2 receptors are distinctly associated with rest-activity rhythms and drug reward

BACKGROUND

Certain components of rest-activity rhythms such as greater eveningness (delayed phase), physical inactivity (blunted amplitude) and shift work (irregularity) are associated with increased risk for drug use. Dopaminergic (DA) signaling has been hypothesized to mediate the associations, though clinical evidence is lacking.

METHODS

We examined associations between rhythm components and striatal D1 (D1R) and D2/3 receptor (D2/3R) availability in 32 healthy adults (12 female, age: 42.40±12.22) and its relationship to drug reward. Rest-activity rhythms were assessed by one-week actigraphy combined with self-reports. [11C]NNC112 and [11C]raclopride Positron Emission Tomography (PET) scans were conducted to measure D1R and D2/3R availability, respectively. Additionally, self-reported drug-rewarding effects of 60 mg oral methylphenidate were assessed.

RESULTS

We found that delayed rhythm was associated with higher D1R availability in caudate, which was not attributable to sleep loss or 'social jet lag', whereas physical inactivity was associated with higher D2/3R availability in nucleus accumbens (NAc). Delayed rest-activity rhythm, higher caudate D1R and NAc D2/3R availability were associated with greater sensitivity to the rewarding effects of methylphenidate.

CONCLUSION

These findings reveal specific components of rest-activity rhythms associated with striatal D1R, D2/3R availability and drug-rewarding effects. Personalized interventions that target rest-activity rhythms may help prevent and treat substance use disorders.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03190954FUNDING. This work was accomplished with support from the National Institute on Alcohol Abuse and Alcoholism (ZIAAA000550).

Cannabis Affects Cerebellar Volume and Sleep Differently in Men and Women

Background: There are known sex differences in behavioral and clinical outcomes associated with drugs of abuse, including cannabis. However, little is known about how chronic cannabis use and sex interact to affect brain structure, particularly in regions with high cannabinoid receptor expression, such as the cerebellum, amygdala, and hippocampus. Based on behavioral data suggesting that females may be particularly vulnerable to the effects of chronic cannabis use, we hypothesized lower volumes in these regions in female cannabis users. We also hypothesized poorer sleep quality among female cannabis users, given recent findings highlighting the importance of sleep for many outcomes related to cannabis use disorder. Methods: Using data from the Human Connectome Project, we examined 170 chronic cannabis users (>100 lifetime uses and/or a lifetime diagnosis of cannabis dependence) and 170 controls that we attempted to match on age, sex, BMI, race, tobacco use, and alcohol use. We performed group-by-sex ANOVAs, testing for an interaction in subcortical volumes, and in self-reported sleep quality (Pittsburgh Sleep Questionnaire Inventory). Results: After controlling for total intracranial volume and past/current tobacco usage, we found that cannabis users relative to controls had smaller cerebellum volume and poorer sleep quality, and these effects were driven by the female cannabis users (i.e., a group-by-sex interaction). Among cannabis users, there was an age of first use-by-sex interaction in sleep quality, such that females with earlier age of first cannabis use tended to have more self-reported sleep issues, whereas this trend was not present among male cannabis users. The amygdala volume was smaller in cannabis users than in non-users but the group by sex interaction was not significant. Conclusions: These data corroborate prior findings that females may be more sensitive to the neural and behavioral effects of chronic cannabis use than males. Further work is needed to determine if reduced cerebellar and amygdala volumes contribute to sleep impairments in cannabis users.

Ketogenic diet reduces alcohol withdrawal symptoms in humans and alcohol intake in rodents

Individuals with alcohol use disorder (AUD) show elevated brain metabolism of acetate at the expense of glucose. We hypothesized that a shift in energy substrates during withdrawal may contribute to withdrawal severity and neurotoxicity in AUD and that a ketogenic diet (KD) may mitigate these effects. We found that inpatients with AUD randomized to receive KD (n = 19) required fewer benzodiazepines during the first week of detoxification, in comparison to those receiving a standard American (SA) diet (n = 14). Over a 3-week treatment, KD compared to SA showed lower "wanting" and increased dorsal anterior cingulate cortex (dACC) reactivity to alcohol cues and altered dACC bioenergetics (i.e., elevated ketones and glutamate and lower neuroinflammatory markers). In a rat model of alcohol dependence, a history of KD reduced alcohol consumption. We provide clinical and preclinical evidence for beneficial effects of KD on managing alcohol withdrawal and on reducing alcohol drinking.

Inducible L-arginine/nitric oxide pathway in human internal mammary artery and saphenous vein

To characterize the L-arginine/nitric oxide (NO) pathway in human vascular smooth muscle (VSM), contractile responses of isolated internal mammary arteries (IMA) and saphenous veins (SV) were observed after induction of NO synthase by interleukin-1 beta (IL-1 beta) or by lipopolysaccharide (LPS). In IL-1 beta-treated endothelium-denuded rings, contractile responses to phenylephrine were reduced in SV rings only. Maximum phenylephrine-induced contraction was depressed by approximately 50%. This was not modified by the presence of indomethacin, NG-nitro-L-arginine methyl ester (L-NAME), or methylene blue (MeB). In LPS-treated vessels, contractile responses were depressed in both SV and IMA rings (40%), and this was not affected by indomethacin. In SV, L-NAME, NG-monomethyl-L-arginine, or MeB did not affect the inhibitory effect of LPS, whereas the effect was reversed in IMA by these inhibitors. In LPS-treated IMA, but not in SV, exogenous L-arginine evoked significant vasodilation (20%). We conclude that VSM of the human IMA possesses an L-arginine/NO pathway inducible by LPS. In SV, LPS or IL-1 beta treatment inhibits contraction by an unidentified system that is not dependent on NO synthase or on guanylate cyclase activities.