Adolescent exposure to MDMA induces dopaminergic toxicity in substantia nigra and potentiates the amyloid plaque deposition in the striatum of APPswe/PS1dE9 mice

Therapeutic Potential of MDMA- and Psychedelic-Assisted Psychotherapy for Adolescent Depression and Trauma

PURPOSE OF REVIEW

There is a mental health crisis affecting youth, and the utility of existing treatments is often limited by lack of effectiveness and tolerability. The aim of this review is to report on outcomes of clinical trials for psilocybin-assisted psychotherapy for adults with depression and MDMA-assisted psychotherapy for adults with post-traumatic stress disorder (PTSD) and discuss recommendations for exploring these treatments in adolescent populations.

RECENT FINDINGS

There have been encouraging data supporting the use of psilocybin-assisted psychotherapy for depression, including previously treatment-resistant symptoms. MDMA-assisted psychotherapy is showing similar promise in treating PTSD, with excellent response and remission rates that appear durable. However, no studies have looked at the use of these treatments in younger patients. The safety and efficacy of psychedelic- and MDMA-assisted psychotherapies should be investigated in adolescents, especially considering the burden of untreated and undertreated psychiatric illness in youth, and the benefits of a potentially earlier, more effective, and more tolerable recovery process. Research and implementation should be tailored to the needs of this population, and equity and access should be considered at every stage. In this novel and rapidly evolving landscape, the psychiatric community is encouraged to advocate for safe, appropriate, and inclusive inquiry into, and application and scaling of these treatment models in adolescent patients.

Dopaminergic dysfunction in the 3xTg-AD mice model of Alzheimer's disease

Alzheimer's disease (AD) is characterized by amyloid (Aβ) protein aggregation and neurofibrillary tangles accumulation, accompanied by neuroinflammation. With all the therapeutic attempts targeting these biomarkers having been unsuccessful, the understanding of early mechanisms involved in the pathology is of paramount importance. Dopaminergic system involvement in AD has been suggested, particularly through the appearance of dopaminergic dysfunction-related neuropsychiatric symptoms and an overall worsening of cognitive and behavioral symptoms. In this study, we reported an early dopaminergic dysfunction in a mouse model presenting both amyloid and Tau pathology. 3xTg-AD mice showed an increase of postsynaptic D_2/3R receptors density in the striatum and D_2/3-autoreceptors in SN/VTA cell bodies. Functionally, a reduction of anxiety-like behavior, an increase in locomotor activity and D₂R hyper-sensitivity to quinpirole stimulation have been observed. In addition, microglial cells in the striatum showed an early inflammatory response, suggesting its participation in dopaminergic alterations. These events are observed at an age when tau accumulation and Aβ deposits in the hippocampus are low. Thus, our results suggest that early dopaminergic dysfunction could have consequences in behavior and cognitive function, and may shed light on future therapeutic pathways of AD.

β‑asarone modulates Beclin‑1, LC3 and p62 expression to attenuate Aβ40 and Aβ42 levels in APP/PS1 transgenic mice with Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly population. Autophagy is a well-known regulator of neurodegenerative diseases and β-asarone has been discovered to have certain neuropharmacological effects. Thus, the present study aimed to analyze the potential effects of β-asarone in AD and its possible mechanism of action in relation to autophagy. The present study investigated the effects of β-asarone on the number of senile plaques and amyloid β(Aβ)₄₀, Aβ₄₂, amyloid precursor protein (APP) and Beclin-1 mRNA levels in the hippocampus of APP/presenilin-1 (PS1) transgenic mice. The possible mechanism of β-asarone on autophagy-related proteins, including Beclin-1, light chain (LC)3A, LC3B and p62 levels, and the number of autophagosomes was also investigated. Mice were divided into a normal control group, a model group, a β-asarone-treated group, a 3-MA-treated group and a rapamycin-treated group. Treatments were continuously administered to all mice for 30 days by intragastric administration. The mice, including those in the normal and model control groups, were given equal volumes of saline. It was demonstrated that β-asarone treatment reduced the number of senile plaques and autophagosomes, and decreased Aβ₄₀, Aβ₄₂, APP and Beclin-1 expression in the hippocampus of model mice compared with untreated model mice. β-asarone also inhibited LC3A/B expression levels, but increased p62 expression. It was deduced that the neuroprotective effects of β-asarone in APP/PS1 transgenic mice resulted from its inhibition of autophagy. In conclusion, the data suggested that β-asarone should be explored further as a potential therapeutic agent in AD.

Effects of MDMA on neuroplasticity, amyloid burden and phospho-tau expression in APPswe/PS1dE9 mice

BACKGROUND

3,4-Methylenedioxymethamphetamine (MDMA) is still one of the most consumed drugs by adolescents. Its abuse is related with cognitive impairment, which seems due to maladaptive plasticity and neural stress. In turn, new hypotheses suggest that Alzheimer's disease (AD) may be promoted by neural stressors.

AIMS AND METHODS

To test if there is an increase in vulnerability to AD after chronic MDMA consumption, we investigated the effects of this drug on recognition memory and its neurotoxic and neuroplastic effects in a transgenic mouse model of presymptomatic familiar AD (APP/PS1 dE9, Tg).

RESULTS

MDMA-treated animals showed recognition memory deficits, regardless of genotype, which were accompanied by changes in plasticity markers. Tg mice showed an impaired expression of Arc compared with wild-type animals, but exposure to MDMA induced an increase in the expression of this factor of the same percentage in both genotypes. However, the expression of c-fos, BDNF and p-CREB was not significantly altered by MDMA treatment in Tg mice. Although Tg mice had higher free choline levels than wild-type mice (about 123%), MDMA did not modify these levels in any case, ruling out any specific effect of this drug on the acetylcholine pathway. MDMA treatment significantly increased the presence of cortical amyloid plaques, as well as Aβ40, Aβ42 and secreted APPβ levels in Tg mice. These plaques were accompanied by increased tau phosphorylation (S199), which does not seem to occur via the canonic pathway involving AKT, CDK5 or GSK3β.

CONCLUSIONS

The present results support previous evidences that MDMA can contribute to the amyloid cascade.