Drug addiction: new targets for an old problem

Classically, exposure to psychotropic stimulants has been primarily associated with damage to dopaminergic neuronal terminals and oxidative stress. However, it is now widely accepted that the interaction between neuronal and glial cells plays a critical role in the development of drug addiction. In this sense, exposure to psychostimulants has been repeatedly shown to produce inflammation in the addicted brain. The existing data evidences that the overall contribution of inflammation to the build up of addiction remains unclear. Contrary to the common held view, our data revealed that methamphetamine (METH), a potent psychostimulant frequently associated to neuroinflammation, cannot stimulate microglia in a cell-autonomous manner. In addition, recent findings evidenced microglia as a multifunctional cell, critical for shaping and refining neuronal connectivity through synaptic plasticity. We hypothesised that the long-term adverse neuropsychiatric consequences occurring within the brain’s reward circuitry under psychostimulat exposure may be due, at least in part, to the underlying neuroinflammatory process, and that limiting it would be relevant to control the addictive behaviour. We show that preventing exacerbated microglial activation and associated neurotoxicity is beneficial at several levels, and that this knowledge can be easily translated into clinical applications.info:eu-repo/semantics/publishedVersio

The insula, a key brain area for bladder pain control, is modulated by stress

Stress may cause or aggravate Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) symptoms. Thus, stress models are being refined to be used as systemic in counterpoint to bladder centric animal models We hypothesised that different stress insults modulate the insula activity diversely. Two models were used in female Wistar rats, Maternal Deprivation Model (MDM, stress applied to new-borns and studies done at 6M) and Water Avoidance Stress test (WAS, stress is applied to 6M rats for 1h every 10 days and studies carried afterwards). Mechanical pain threshold was evaluated in L6/S1 dermatomes which share the spinal cord segments of bladder sensory innervation. Bladder function was evaluated by cystometry. Then Insulas were removed. One was immersed in RNAlater, homogenized, RNA extracted, and expression of different biomarkers assessed by real-time PCR. The other insula was immunoreacted against microglia markers Iba1 and Cd68. The analysis of positive cells used LASAF and ImageJ software. Morphometric analysis and 3D reconstructions used IMARIS software.info:eu-repo/semantics/publishedVersio

Methamphetamine promotes a-tubulin deacetylation in endothelial cells: The protective role of acetyl-L-carnitine

Methamphetamine (METH) is a powerful psychostimulant drug used worldwide for its reinforcing properties. In addition to the classic long-lasting monoaminergic-disrupting effects extensively described in the literature, METH has been consistently reported to increase blood brain barrier (BBB) permeability, both in vivo and in vitro, as a result of tight junction and cytoskeleton disarrangement. Microtubules play a critical role in cell stability, which relies on post-translational modifications such as a-tubulin acetylation. As there is evidence that psychostimulants drugs modulate the expression of histone deacetylases (HDACs), we hypothesized that in endothelial cells METH-mediation of cytoplasmatic HDAC6 activity could affect tubulin acetylation and further contribute to BBB dysfunction. To validate our hypothesis, we exposed the bEnd.3 endothelial cells to increasing doses of METH and verified that itleads to an extensivea-tubulin deacetylation mediated by HDACs activation. Furthermore, since we recently reported that acetyl-L-carnitine (ALC), a natural occurring compound, prevents BBB structural loss in a context of METH exposure, we reasoned that ALC could also preserve the acetylation of microtubules under METH action. The present results confirm that ALC is able to prevent METH-induced deacetylation providing effective protection on microtubule acetylation. Although further investigation is still needed, HDACs regulation may become a new therapeutic target for ALC

Acetil-L-Carnitina como neuroprotetor na excitotoxicidade do glutamato

A excitotoxicidade consiste na ativação excessiva de recetores de glutamato, causada pela acumulação extracelular deste neurotransmissor. A ativação dos recetores de glutamato promove o aumento excessivo da concentração intracelular de cálcio e morte neuronal associada à ativação de protéases como calpaínas e caspases - acontecimentos típicos de patologias como isquémia cerebral, Alzheimer, Parkinson e Huntington. A acetil-L-carnitina (ALC) é um éster da L-carnitina com funções neuroprotetoras, mas o mecanismo envolvido permanece desconhecido.info:eu-repo/semantics/publishedVersio

Acetyl-L-Carnitine Prevents Methamphetamine-Induced Structural Damage on Endothelial Cells via ILK-Related MMP-9 Activity

Abstract Methamphetamine (METH) is a potent psychostimulant highly used worldwide. Recent studies evidenced the involvement of METH in the breakdown of the blood-brain-barrier (BBB) integrity leading to compromised function. The involvement of the matrix metalloproteinases (MMPs) in the degradation of the neurovascular matrix components and tight junctions (TJs) is one of the most recent findings in METH-induced toxicity. As BBB dysfunction is a pathological feature of many neurological conditions, unveiling new protective agents in this field is of major relevance. Acetyl- L-carnitine (ALC) has been described to protect the BBB function in different paradigms, but the mechanisms underlying its action remain mostly unknown. Here, the immortalized bEnd.3 cell line was used to evaluate the neuroprotective features of ALC in METH-induced damage. Cells were exposed to ranging concentrations of METH, and the protective effect of ALC 1 mM was assessed 24 h after treatment. F-actin rearrangement, TJ expression and distribution, and MMPs activity were evaluated. Integrin-linked kinase (ILK) knockdown cells were used to assess role of ALC in ILK mediated METH-triggered MMPs’ activity. Our results show that METH led to disruption of the actin filaments concomitant with claudin-5 translocation to the cytoplasm. These events were mediated by MMP-9 activation in association with ILK overexpression. Pretreatment with ALC prevented METH-induced activation of MMP-9, preserving claudin-5 location and the structural arrangement of the actin filaments. The present results support the potential of ALC in preserving BBB integrity, highlighting ILK as a new target for the ALC therapeutic use.info:eu-repo/semantics/publishedVersio

NanoSPECT/MRI: a “new generation” high performance tool in pre-clinical imaging

Abstract Body: PreClinical Imaging it is an each-day evolving field, getting more and more important at distinct areas. The Biotechnology field is between those that taken the biggest benefit. With so much interest, it is not surprising that investment consented on Research and Development is also evolving at the same time that this specific branch of business into the Imaging Industry is getting more and more attention and growing in importance. Hybrid Imaging is also getting more and more interest in the last decade and actually there are different vendors proposing interesting technical solutions, making things easier for one that has the possibilities – and the knowledge about each will be the most adequate for the specific purpose on each situation! – to choose one (or more) of those solutions. This paper relates with the public presentation of images produced from the world first model of a new pre-clinical imaging system, an new equipment that mixes Nuclear Medicine and MRI Magnetic Resonance Imaging techniques, using as base the sub-millimeter Nano-SPECT (Single Photon Emission Computed Tomography), so an high-level performance system – the world reference, produced by MEDISO Company, in Hungary - from Nuclear Medicine and a new MRI component, optimized for Neurosciences, but able to perform adequately on other critical biological fields. As practical example from the possibilities being introduced, images from mice, which are being enrolled on a Neuroscience project, will be showed and will be discussed, but also will be compared with other images being produced on other, actually more current, technical solutions, in order to try to demonstrate the advantages and disadvantages of this specific new approach. Since this small – quick and unpretentious – comparison will be done, it is meant to make possible understanding the place and the real possibilities of this equipment, which it is expected to become available on the world market between the end of this year and the 1st Quarter from next year

The impact of psychostimulants on central and peripheral neuro-immune regulation: a scoping review of cytokine profiles and their implications for addiction

It is now well-accepted that psychostimulants act on glial cells causing neuroinflammation and adding to the neurotoxic effects of such substances. Neuroinflammation can be described as an inflammatory response, within the CNS, mediated through several cytokines, reactive oxygen species, chemokines and other inflammatory markers. These inflammatory players, in particular cytokines, play important roles. Several studies have demonstrated that psychostimulants impact on cytokine production and release, both centrally and at the peripheral level. Nevertheless, the available data is often contradictory. Because understanding how cytokines are modulated by psychoactive substances seems crucial to perspective successful therapeutic interventions, here, we conducted a scoping review of the available literature. We have focused on how different psychostimulants impact on the cytokine profile. Publications were grouped according to the substance addressed (methamphetamine, cocaine, methylphenidate, MDMA or other amphetamines), the type of exposure and period of evaluation (acute, short- or long-term exposure, withdrawal, and reinstatement). Studies were further divided in those addressing central cytokines, circulating (peripheral) levels, or both. Our analysis showed that the classical pro-inflammatory cytokines TNF-α, IL-6, and IL-1β were those more investigated. The majority of studies have reported increased levels of these cytokines in the central nervous system after acute or repeated drug. However, studies investigating cytokine levels during withdrawal or reinstatement have shown higher variability in their findings. Although we have identified fewer studies addressing circulating cytokines in humans, the available data suggest that the results may be more robust in animal models than in patients with problematic drug use. As a major conclusion, an extensive use of arrays for relevant cytokines should be considered to better determine which cytokines, upon the classical ones, may be involved in the progression from episodic use to the development of addiction. A concerted effort is still necessary to address the link between peripheral and central immune players, including from a longitudinal perspective. Until there, the identification of new biomarkers and therapeutic targets to envision personalized immune-based therapeutics will continue to be unlikely.info:eu-repo/semantics/publishedVersio

Chronic ketamine administration impairs mitochondrial complex I in the rat liver

Aim Ketamine can induce hepatotoxicity which has been suggested to be dependent on mitochondrial impairment. This study investigated the long-term effects of chronic low-dose ketamine on liver mitochondrial function, oxidative stress parameters, liver histology and glycogen content. Main methods Adult rats were administered with saline or ketamine (5 or 10 mg/kg) twice a day for a fourteen-day period in order to mimic chronic treatments. Effects between groups were compared ten days after the treatment had ended. Liver mitochondrial function was monitored in isolated mitochondrial extracts through evaluation of respiration parameters and activity of respiratory complexes, as well as oxidative stress, through lipid peroxidation, protein oxidation and superoxide dismutase activity. The hepatic histology and liver glycogen content were also evaluated. Key findings Ketamine groups showed a decreased evolution in body weight gains during the treatment period. Ketamine had no effect either on serum liver enzymes or on the oxidative stress parameters of liver mitochondria. Ketamine decreased the hepatic glycogen content, inhibited mitochondrial complex I and oxygen consumption when glutamate–malate substrate was used. Significance These findings reflect a long-term mitochondrial bioenergetic deterioration induced by ketamine, which may explain the increased susceptibility of some patients to its prolonged or repeated use.info:eu-repo/semantics/publishedVersio

ALC Neuroprotection through autophagy and ups acitivity

Acetyl–L-carnitine (ALC) has beneficial effects in neurodegenerative diseases and was shown to be protective against exposure to methamphetamine (METH) reducing mitochondrial dysfunction and oxidative stress. However, the mechanisms underlying ALC action are still unknown, limiting its putative therapeutic use

Long-term effects of chronic cocaine exposure throughout adolescence on anxiety and stress responsivity in a wistar rat model

Adolescents display increased vulnerability to engage in drug experimentation. This is often considered a risk factor for later drug abuse. In this scenario, the permanent effects of cocaine exposure during adolescence on anxiety levels and stress responsivity, which may result in behavioral phenotypes prone to addiction, are now starting to be unveiled. Thus, the purpose of the present study was to evaluate the long-lasting effects of chronic cocaine administration during adolescence, on anxiety-like behavior and on stress response. Adolescent male Wistar rats were daily administered 45-mg cocaine/kg of body weight in three equal intraperitoneal doses with 1-h interval, from postnatal day (PND) 35 to 50. The effects of cocaine administration on anxiety levels, assessed in the Elevated Plus Maze (EPM), and on social stress response, assessed in the resident-intruder paradigm (R/I), were evaluated 10 days after withdrawal, when rats were reaching the adulthood. The underlying dopaminergic activity, and the corticosterone and testosterone levels were determined. Our results showed that cocaine induced long-lasting alterations in the hypothalamus-pituitary-adrenals (HPA) axis function and in testosterone levels. Such alterations resulted in significant and enduring changes in behavioral responses to environmental challenges, such as the EPM and R/I, including the evaluation of potential threats that may lead to high-risk behavior and low-benefit choices. This was further supported by an altered dopaminergic function in the amygdala and hippocampus. The present findings provide new insights into how the use of cocaine during adolescent development may modulate emotional behavior later in life. Compromised ability to recognize and deal with potential threats is an important risk factor to perpetuate compulsive drug seeking and relapse susceptibility.info:eu-repo/semantics/publishedVersio