Not just the brain: methamphetamine disrupts blood-spinal cord barrier and induces acute glial activation and structural damage of spinal cord cells

Methamphetamine induces a low dopamine transporter expressing state without altering the total number of peripheral immune cells

Methamphetamine is a widely abused psychostimulant and one of the main targets of dopamine transporter (DAT). Methamphetamine reduces DAT-mediated dopamine uptake and stimulates dopamine efflux leading to increased synaptic dopamine levels many folds above baseline. Methamphetamine also targets DAT-expressing peripheral immune cells, reduces wound healing and increases infection susceptibility. Peripheral immune cells such as myeloid cells, B cells and T cells express DAT. DAT activity on monocytes and macrophages exhibits immune suppressive properties via an autocrine paracrine mechanism, where deletion or inhibition of DAT activity increases inflammatory responses. In this study, utilizing a mouse model of daily single dose of methamphetamine administration, we investigated the impact of the drug on DAT expression in peripheral immune cells. We found in methamphetamine-treated mice that DAT expression was down-regulated in most of the innate and adaptive immune cells. Methamphetamine did not increase or decrease the total number of innate and adaptive immune cells but changed their immunophenotype to low-DAT-expressing phenotype. Moreover, serum cytokine distributions were altered in methamphetamine-treated mice. Therefore, resembling its effect in the CNS, in the periphery, methamphetamine regulates DAT expression on peripheral immune cell subsets, potentially describing methamphetamine regulation of peripheral immunity.

Co-Administration of Nanowired Monoclonal Antibodies to Inducible Nitric Oxide Synthase and Tumor Necrosis Factor Alpha Together with Antioxidant H-290/51 Reduces SiO2 Nanoparticles-Induced Exacerbation of Pathophysiology of Spinal Cord Trauma

Military personnel are often exposed to silica dust during combat operations across the globe. Exposure to silica dust in US military or service personnel could cause Desert Strom Pneumonitis also referred to as Al Eskan disease causing several organs damage and precipitate autoimmune dysfunction. However, the effects of microfine particles of sand inhalation-induced brain damage on the pathophysiology of traumatic brain or spinal cord injury are not explored. Previously intoxication of silica nanoparticles (50-60 nm size) is shown to exacerbates spinal cord injury induces blood-spinal cord barrier breakdown, edema formation and cellular changes. However, the mechanism of silica nanoparticles-induced cord pathology is still not well known. Spinal cord injury is well known to alter serotonin (5-hydroxytryptamine) metabolism and induce oxidative stress including upregulation of nitric oxide synthase and tumor necrosis factor alpha. This suggests that these agents are involved in the pathophysiology of spinal cord injury. In this review, we examined the effects of combined nanowired delivery of monoclonal antibodies to neuronal nitric oxide synthase (nNOS) together with tumor necrosis factor alpha (TNF-α) antibodies and a potent antioxidant H-290/51 to induce neuroprotection in spinal cord injury associated with silica nanoparticles intoxication. Our results for the first time show that co-administration of nanowired delivery of antibodies to nNOS and TNF-α with H-290/51 significantly attenuated silica nanoparticles-induced exacerbation of spinal cord pathology, not reported earlier.

Nanowired Delivery of Mesenchymal Stem Cells with Antioxidant Compound H-290/51 Reduces Exacerbation of Methamphetamine Neurotoxicity in Hot Environment

Military personnel are often exposed to hot environments either for combat operations or peacekeeping missions. Hot environment is a severe stressful situation leading to profound hyperthermia, fatigue and neurological impairments. To avoid stressful environment, some people frequently use methamphetamine (METH) or other psychostimulants to feel comfortable under adverse situations. Our studies show that heat stress alone induces breakdown of the blood-brain barrier (BBB) and edema formation associated with reduced cerebral blood flow (CBF). On the other hand, METH alone induces hyperthermia and neurotoxicity. These effects of METH are exacerbated at high ambient temperatures as seen with greater breakdown of the BBB and brain pathology. Thus, a combination of METH use at hot environment may further enhance the brain damage-associated behavioral dysfunctions. METH is well known to induce severe oxidative stress leading to brain pathology. In this investigation, METH intoxication at hot environment was examined on brain pathology and to explore suitable strategies to induce neuroprotection. Accordingly, TiO₂-nanowired delivery of H-290/51 (150 mg/kg, i.p.), a potent chain-breaking antioxidant in combination with mesenchymal stem cells (MSCs), is investigated in attenuating METH-induced brain damage at hot environment in model experiments. Our results show that nanodelivery of H-290/51 with MSCs significantly enhanced CBF and reduced BBB breakdown, edema formation and brain pathology following METH exposure at hot environment. These observations are the first to point out that METH exacerbated brain pathology at hot environment probably due to enhanced oxidative stress, and MSCs attenuate these adverse effects, not reported earlier.

Nanowired Delivery of Curcumin Attenuates Methamphetamine Neurotoxicity and Elevates Levels of Dopamine and Brain-Derived Neurotrophic Factor

Curcumin is a well-known antioxidant used as traditional medicine in China and India since ages to treat variety of inflammatory ailments as a food supplement. Curcumin has antitumor properties with neuroprotective effects in Alzheimer's disease. Curcumin elevates brain-derived neurotrophic factor (BDNF) and dopamine (DA) levels in the brain indicating its role in substance abuse. Methamphetamine (METH) is one of the most abused substances in the world that induces profound neurotoxicity by inducing breakdown of the blood-brain barrier (BBB), vasogenic edema and cellular injuries. However, influence of curcumin on METH-induced neurotoxicity is still not well investigated. In this investigation, METH neurotoxicity and neuroprotective effects of curcumin nanodelivery were examined in a rat model. METH (20 mg/kg, i.p.) neurotoxicity is evident 4 h after its administration exhibiting breakdown of BBB to Evans blue albumin in the cerebral cortex, hippocampus, cerebellum, thalamus and hypothalamus associated with vasogenic brain edema as seen measured using water content in all these regions. Nissl attaining exhibited profound neuronal injuries in the regions of BBB damage. Normal curcumin (50 mg/kg, i.v.) 30 min after METH administration was able to reduce BBB breakdown and brain edema partially in some of the above brain regions. However, TiO₂ nanowired delivery of curcumin (25 mg/kg, i.v.) significantly attenuated brain edema, neuronal injuries and the BBB leakage in all the brain areas. BDNF level showed a significant higher level in METH-treated rats as compared to saline-treated METH group. Significantly enhanced DA levels in METH-treated rats were also observed with nanowired delivery of curcumin. Normal curcumin was able to slightly elevate DA and BDNF levels in the selected brain regions. Taken together, our observations are the first to show that nanodelivery of curcumin induces superior neuroprotection in METH neurotoxicity probable by enhancing BDNF and DA levels in the brain, not reported earlier.

Mechanism underlying circularRNA_014301-mediated regulation of neuronal cell inflammation and apoptosis

Spinal cord injury (SCI) causes damage to the spinal cord owing to trauma or disease and myelinated fiber tracts that transmit sensation and motor signals to and from the brain. Circular RNAs (circRNAs) are a recently discovered class of regulatory molecules, and their roles in SCI are still unknown. circRNA_014301 was indicated to be differentially expressed in the spinal cord at the site of SCI in a rat model. To analyze the role of circRNA_014301 in SCI, we exposed rat adrenal pheochromocytoma PC12 cells were exposed to increasing concentrations of lipopolysaccharide (LPS) and to construct a PC12 cell inflammatory model. Cell Counting Kit-8 assay was used to analyze cell viability. Reverse transcription-quantitative PCR and ELISA were used to detect the expression of inflammatory factors (IL-1β, IL-6 and TNF-α). Annexin V-FITC/PI double staining was employed to detect cell apoptosis, and western blotting was performed to detect the expression of apoptotic proteins (Bax/Bcl-2/cleaved caspase-3) and NF-κB. The results demonstrated that LPS induced inflammation in PC12 cells as evidenced by the reduced cell proliferation and enhanced expression of inflammatory and apoptotic factors under increasing LPS concentrations. Western blotting analyses indicated that circRNA_014301 induced the expression of p-NF-κB/NF-κB, Bax and cleaved caspase-3, and decreased the expression of Bcl-2 following LPS-induced inflammation, and this apoptosis-promoting effect was relieved by small interfering-RNA-mediated knockdown of circRNA_014301. Thus, circRNA_014301 silencing alleviated apoptosis and inflammation in PC12 cells. SCI is invariably associated with spinal cord inflammation, and LPS was used to stimulate apoptosis and inflammatory injury in PC12 cells, and create a cell model of SCI. By promoting PC12 cell apoptosis under inflammatory conditions, it was indicated that circRNA_014301 may suppress SCI. Therefore, circRNA_014301 may represent a potential target for SCI diagnosis and therapy.

Methamphetamine exacerbates pathophysiology of traumatic brain injury at high altitude. Neuroprotective effects of nanodelivery of a potent antioxidant compound H-290/51

Military personnel are often exposed to high altitude (HA, ca. 4500-5000m) for combat operations associated with neurological dysfunctions. HA is a severe stressful situation and people frequently use methamphetamine (METH) or other psychostimulants to cope stress. Since military personnel are prone to different kinds of traumatic brain injury (TBI), in this review we discuss possible effects of METH on concussive head injury (CHI) at HA based on our own observations. METH exposure at HA exacerbates pathophysiology of CHI as compared to normobaric laboratory environment comparable to sea level. Increased blood-brain barrier (BBB) breakdown, edema formation and reductions in the cerebral blood flow (CBF) following CHI were exacerbated by METH intoxication at HA. Damage to cerebral microvasculature and expression of beta catenin was also exacerbated following CHI in METH treated group at HA. TiO2-nanowired delivery of H-290/51 (150mg/kg, i.p.), a potent chain-breaking antioxidant significantly enhanced CBF and reduced BBB breakdown, edema formation, beta catenin expression and brain pathology in METH exposed rats after CHI at HA. These observations are the first to point out that METH exposure in CHI exacerbated brain pathology at HA and this appears to be related with greater production of oxidative stress induced brain pathology, not reported earlier.

Toxic Effects of Methamphetamine on Perivascular Health: Co-morbid Effects of Stress and Alcohol Use Disorders

Methamphetamine (Meth) abuse presents a global problem and commonly occurs with stress and/or alcohol use disorders. Regardless, the biological causes and consequences of these comorbidities are unclear. Whereas the mechanisms of Meth, stress, and alcohol abuse have been examined individually and well-characterized, these processes overlap significantly and can impact the neural and peripheral consequences of Meth. This review focuses on the deleterious cardio- and cerebrovascular effects of Meth, stress, alcohol abuse, and their comorbid effects on the brain and periphery. Points of emphasis are on the composition of the blood-brain barrier and their effects on the heart and vasculature. The autonomic nervous system, inflammation, and oxidative stress are specifically highlighted as common mediators of the toxic consequences to vascular and perivascular health. A significant portion of the Meth abusing population also presents with stress and alcohol use disorders, prompting a need to understand the mechanisms underlying their comorbidities. Little is known about their possible convergent effects. Therefore, the purpose of this critical review is to identify shared mechanisms of Meth, chronic stress, and alcohol abuse that contributes to the dysfunction of vascular health and underscores the need for studies that directly address their interactions.

Neuronal and peripheral damages induced by synthetic psychoactive substances: an update of recent findings from human and animal studies

Preclinical and clinical studies indicate that synthetic psychoactive substances, in addition to having abuse potential, may elicit toxic effects of varying severity at the peripheral and central levels. Nowadays, toxicity induced by synthetic psychoactive substances poses a serious harm for health, since recreational use of these substances is on the rise among young and adult people. The present review summarizes recent findings on the peripheral and central toxicity elicited by “old” and “new” synthetic psychoactive substances in humans and experimental animals, focusing on amphetamine derivatives, hallucinogen and dissociative drugs and synthetic cannabinoids.

RETRACTED: Angelica polysaccharide protects PC-12 cells from lipopolysaccharide-induced injury via down-regulating microRNA-223

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concerns were initially raised regarding the Western Blots from Figures 1C, 1G, 2B, 2D, 4D, 4F, 5 (left panel), 6C and 6E. Given also the comments of Dr Elisabeth Bik regarding this article “… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated”, the journal requested the authors to provide the raw data. The authors have not provided raw data of sufficient quality and detail to support the authors’™ claim and therefore the Editor-in-Chief decided to retract the article.

The impact of methamphetamines in patients with traumatic brain injury, a retrospective review

OBJECTIVE

Both neurotoxic and neuroprotective effects of methamphetamines (METH) are being studied. There are few studies evaluating the effects of METH on patients with traumatic brain injury (TBI). The objective of this study is to compare clinical outcomes after TBI in METH users versus non-METH users.

PATIENT AND METHODS

A retrospective review of 304 patients with severe traumatic head injury were performed. Patients were evaluated and stratified based on toxicology screening for methamphetamines (METH) or none. Of the patients reviewed with a full toxicology, 24 of those patients were positive for METH, and 60 patients were negative. Patients were evaluated based on demographics, type of injury, Glasgow Coma Scale (GCS), and Glasgow Outcome Scale (GOS).

RESULTS

METH patients were younger upon presentation (43.5 versus 55.8, p = 0.003), with a larger improvement in GCS and GOS upon discharge (P = 0.012, 0.0001 respectively). There was no significant difference in length of hospital stay, initial presenting GCS and GOS, or discharge GCS and GOS.

CONCLUSIONS

Our findings demonstrate an improved change in GCS and GOS for those positive with METH than those without. Surprisingly, substance positive patients did not have a worse outcome score. Further investigation is necessary to evaluate the potential neuro-protective effects of METH in TBI.

Neuroimmune Axes of the Blood-Brain Barriers and Blood-Brain Interfaces: Bases for Physiological Regulation, Disease States, and Pharmacological Interventions

Central nervous system (CNS) barriers predominantly mediate the immune-privileged status of the brain, and are also important regulators of neuroimmune communication. It is increasingly appreciated that communication between the brain and immune system contributes to physiologic processes, adaptive responses, and disease states. In this review, we discuss the highly specialized features of brain barriers that regulate neuroimmune communication in health and disease. In section I, we discuss the concept of immune privilege, provide working definitions of brain barriers, and outline the historical work that contributed to the understanding of CNS barrier functions. In section II, we discuss the unique anatomic, cellular, and molecular characteristics of the vascular blood-brain barrier (BBB), blood-cerebrospinal fluid barrier, and tanycytic barriers that confer their functions as neuroimmune interfaces. In section III, we consider BBB-mediated neuroimmune functions and interactions categorized as five neuroimmune axes: disruption, responses to immune stimuli, uptake and transport of immunoactive substances, immune cell trafficking, and secretions of immunoactive substances. In section IV, we discuss neuroimmune functions of CNS barriers in physiologic and disease states, as well as pharmacological interventions for CNS diseases. Throughout this review, we highlight many recent advances that have contributed to the modern understanding of CNS barriers and their interface functions.

Acceleration of cardiovascular-biological age by amphetamine exposure is a power function of chronological age

BACKGROUND

Amphetamine abuse is becoming more widespread internationally. The possibility that its many cardiovascular complications are associated with a prematurely aged cardiovascular system, and indeed biological organism systemically, has not been addressed.

METHODS

Radial arterial pulse tonometry was performed using the SphygmoCor system (Sydney). 55 amphetamine exposed patients were compared with 107 tobacco smokers, 483 non-smokers and 68 methadone patients (total=713 patients) from 2006 to 2011. A cardiovascular-biological age (VA) was determined.

RESULTS

The age of the patient groups was 30.03±0.51-40.45±1.15 years. This was controlled for with linear regression. The sex ratio was the same in all groups. 94% of amphetamine exposed patients had used amphetamine in the previous week. When the (log) VA was regressed against the chronological age (CA) and a substance-type group in both cross-sectional and longitudinal models, models quadratic in CA were superior to linear models (both p<0.02). When log VA/CA was regressed in a mixed effects model against time, body mass index, CA and drug type, the cubic model was superior to the linear model (p=0.001). Interactions between CA, (CA)² and (CA)³ on the one hand and exposure type were significant from p=0.0120. The effects of amphetamine exposure persisted after adjustment for all known cardiovascular risk factors (p<0.0001).

CONCLUSIONS

These results show that subacute exposure to amphetamines is associated with an advancement of cardiovascular-organismal age both over age and over time, and is robust to adjustment. That this is associated with power functions of age implies a feed-forward positively reinforcing exacerbation of the underlying ageing process.

Propitious Therapeutic Modulators to Prevent Blood-Spinal Cord Barrier Disruption in Spinal Cord Injury

The blood-spinal cord barrier (BSCB) is a specialized protective barrier that regulates the movement of molecules between blood vessels and the spinal cord parenchyma. Analogous to the blood-brain barrier (BBB), the BSCB plays a crucial role in maintaining the homeostasis and internal environmental stability of the central nervous system (CNS). After spinal cord injury (SCI), BSCB disruption leads to inflammatory cell invasion such as neutrophils and macrophages, contributing to permanent neurological disability. In this review, we focus on the major proteins mediating the BSCB disruption or BSCB repair after SCI. This review is composed of three parts. Section 1. SCI and the BSCB of the review describes critical events involved in the pathophysiology of SCI and their correlation with BSCB integrity/disruption. Section 2. Major proteins involved in BSCB disruption in SCI focuses on the actions of matrix metalloproteinases (MMPs), tumor necrosis factor alpha (TNF-α), heme oxygenase-1 (HO-1), angiopoietins (Angs), bradykinin, nitric oxide (NO), and endothelins (ETs) in BSCB disruption and repair. Section 3. Therapeutic approaches discusses the major therapeutic compounds utilized to date for the prevention of BSCB disruption in animal model of SCI through modulation of several proteins.

Breakdown of Blood-Brain and Blood-Spinal Cord Barriers During Acute Methamphetamine Intoxication: Role of Brain Temperature

Methamphetamine (METH) is a powerful and often-abused stimulant with potent addictive and neurotoxic properties. While it is generally believed that structural brain damage induced by METH results from oxidative stress, in this work we present data suggesting robust disruption of blood-brain and blood-spinal cord barriers during acute METH intoxication in rats. We demonstrate the relationships between METH-induced brain hyperthermia and widespread but structure-specific barrier leakage, acute glial cell activation, changes in brain water and ionic homeostasis, and structural damage of different types of cells in the brain and spinal cord. Therefore, METH-induced leakage of the blood-brain and blood-spinal cord barriers is a significant contributor to different types of functional and structural brain abnormalities that determine acute toxicity of this drug and possibly neurotoxicity during its chronic use.