Development of memantine as a drug for Alzheimer’s disease: A review of preclinical and clinical studies

Excitotoxicity contributes to neuronal cell death due to overstimulation of N-methyl-D-aspartate (NMDA) receptors by glutamate, which plays a significant role in the development and progression of Alzheimer’s disease (AD) and other neurodegenerative disorders. Studies have been conducted to identify a well-tolerated and selective NMDA receptor blocker in an effort to alleviate neurodegeneration. Memantine has been found to induce a distinct low-affinity NMDA receptor blockade in both preclinical and clinical studies Therefore, FDA approved this drug as a well-tolerated noncompetitive NMDA receptor blocker for treating moderate to severe cases of AD. Further, memantine showed neuroprotective effects in preclinical studies by selectively blocking excessive NMDA receptor activation. Altogether, this novel drug is well-tolerated and effective for treating moderate to severe AD in various clinical studies. This paper is a review of preclinical and clinical studies on the drug development process of memantine. Keywords: Memantine, Excitotoxicity, N-methyl-D-aspartate, Glutamate, Alzheimer’s disease, neurodegeneratio

Alcohol Consumption Impairs the Ependymal Cilia Motility in the Brain Ventricles

Ependymal cilia protrude into the central canal of the brain ventricles and spinal cord to circulate the cerebral spinal fluid (CSF). Ependymal cilia dysfunction can hinder the movement of CSF leading to an abnormal accumulation of CSF within the brain known as hydrocephalus. Although the etiology of hydrocephalus was studied before, the effects of ethanol ingestion on ependymal cilia function have not been investigated in vivo. Here, we report three distinct types of ependymal cilia, type-I, type-II and type-III classified based upon their beating frequency, their beating angle, and their distinct localization within the mouse brain-lateral ventricle. Our studies show for the first time that oral gavage of ethanol decreased the beating frequency of all three types of ependymal cilia in both the third and the lateral rat brain ventricles in vivo. Furthermore, we show for the first time that hydin, a hydrocephalus-inducing gene product whose mutation impairs ciliary motility, and polycystin-2, whose ablation is associated with hydrocephalus are colocalized to the ependymal cilia. Thus, our studies reinforce the presence of three types of ependymal cilia in the brain ventricles and demonstrate the involvement of ethanol as a risk factor for the impairment of ependymal cilia motility in the brain

Effects of MS-153 on chronic ethanol consumption and GLT1 modulation of glutamate levels in male alcohol-preferring rats

We have recently shown that upregulation of glutamate transporter 1 (GLT1) in the brain is associated in part with reduction in ethanol intake in alcohol-preferring (P) male rats. In this study, we investigated the effects of a synthetic compound, (R)-(−)-5-methyl-1-nicotinoyl-2-pyrazoline (MS-153), known to activate GLT1 on ethanol consumption as well as GLT1 expression and certain signaling pathways in P rats. P rats were given 24-hour concurrent access to 15% and 30% ethanol, water and food for five weeks. On week 6, P rats received MS-153 at a dose of 50 mg/kg (i.p.) or a vehicle (i.p.) for five consecutive days. We also tested the effect of MS-153 on daily sucrose (10%) intake. Our studies revealed a significant decrease in ethanol intake at the dose of 50 mg/kg MS-153 from Day 1 through Day 14. In addition, MS-153 at dose of 50 mg/kg did not induce any significant effect on sucrose intake. Importantly, we found that MS-153 upregulated the GLT1 level in the nucleus accumbens (NAc) but not in the prefrontal cortex (PFC). In accordance, we found upregulation of nuclear NFkB-65 level in NAc in MS-153-treated group, however, IkB was downregulated in MS-153-treated group in NAc. We did not find any changes in NFkB-65 and IkB levels in PFC. Interestingly, we revealed that p-Akt was downregulated in ethanol vehicle treated groups in the NAc; this downregulation was reversed by MS-153 treatment. We did not observe any significant differences in glutamate aspartate transporter (GLAST) expression among all groups. These findings reveal MS-153 as a GLT1 modulator that may have potential as a therapeutic drug for the treatment of alcohol dependence

Separation of Isomeric Forms of Urolithin Glucuronides Using Supercritical Fluid Chromatography

Producción CientíficaUrolithins are gut microbiota metabolites produced in humans after consuming foods containing ellagitannins and ellagic acid. Three urolithin metabotypes have been reported for different individuals depending on the final urolithins produced. After absorption, they are conjugated with glucuronic acid (phase II metabolism), and these are the main circulating metabolites in plasma and reach different tissues. Different regioisomeric isomers of urolithin glucuronides have been described. Still, their identification and quantification in humans have not been properly reported due to resolution limitations in their analysis by reversed-phase high-performance liquid chromatography. In the present study, we report a novel method for separating these isomers using supercritical fluid chromatography. With this method, urolithin A 3- and 8-glucuronide, isourolithin A 3- and 9- glucuronide, and urolithin B 3-glucuronide (8-hydroxy urolithin 3-glucuronide; 3-hydroxy urolithin 8-glucuronide; 3-hydroxyurolithin 9-glucuronide; 9-hydroxyurolithin 3-glucuronide; and urolithin 3-glucuronide) were separated in less than 15 min. The proposed method was applied to successfully analyze these metabolites in urine samples from different volunteers belonging to different metabotypes.Taif University (TURSP- HC2021/3

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Quetiapine-Induced Place Preference in Mice: Possible Dopaminergic Pathway

Quetiapine, an atypical antipsychotic, is effective in the management of schizophrenia, depression, and anxiety. Although quetiapine overdosage and misuse have been reported, its abuse potential has not been investigated in animals. In this study, the abuse potential of quetiapine was assessed based on the conditioned place preference (CPP) paradigm of drug addiction in a mouse model. First, mice received intraperitoneal injections of quetiapine (40, 80, or 120 mg/kg) every other day during the conditioning phase. In the second experiment, mice were pretreated with 0.03 mg/kg SKF-35866, a D1 receptor antagonist, before receiving saline or quetiapine (120 mg/kg) during the conditioning phase. No significant changes in time spent in the quetiapine-paired chamber were observed compared with time spent in the saline-paired chamber in mice treated with 40 or 80 mg/kg. In contrast, the preference to the quetiapine-paired chamber was significantly increased in mice treated with 120 mg/kg quetiapine, and this effect was blocked by SKF-35866 pretreatment. These results demonstrated, for the first time, the abuse potential of quetiapine in an animal model of drug addiction. Interestingly, this CPP-inducing effect was likely mediated by activating D1 receptors

Potential Association between the Use of Anabolic Steroids and COVID-19 Infection

Anabolic androgenic steroids (AASs) are synthetic analogs of testosterone that can affect the immune system. Bodybuilders and sportsmen are at risk of abusing AASs. The aim of this study was to investigate the association between AASs use and coronavirus disease (COVID-19). This cross-sectional study included adults aged 18 years and above. Between 16 April and 23 June 2021, gym-attending participants completed an online survey. Multivariable analysis was performed using multiple logistic regression to identify factors associated with COVID-19 diagnosis and severity. Current use of AASs was reported in 7.5% of the 520 study participants. Approximately 20% of the study participants reported that they had contracted COVID-19, approximately half of whom reported moderate to severe disease. Contracting COVID-19 was reported more frequently by current users than by non-current users (35.90% vs. 18.92%, p = 0.011). Multivariable analysis revealed that contracting COVID-19 was nearly five times more likely among current users of AASs than among non-current users (OR = 4.89, 95% CI: 1.69–14.13). Current use of AASs was also associated with greater odds of moderate to severe COVID-19 disease (OR = 3.71, 95% CI: 1.04–13.21). Our findings suggest that the use of AASs could be an underlying risk factor for COVID-19 severity

Oral self-administration of pregabalin in a mouse model and the resulting drug addiction features

Prescription drug abuse is an issue that is rapidly growing globally. Pregabalin, an anticonvulsant, analgesic, and anxiolytic medication, is effective in the management of multiple neurological disorders; however, there is increasing concern regarding its widespread illicit use. It has been previously reported in mice that pregabalin can induce conditioned place preference. In this current investigation, the potential of pregabalin to elicit free-choice drinking in a mouse model of drug addiction, and its effect on recognition and withdrawal behaviors after forced abstinence, were studied. Twenty-two male BALB/c mice were randomly divided into three groups (n = 7–8/group); control, pregabalin-30, and pregabalin-60. The study had three phases: habituation (days 1–5) with free water access, free-choice drinking (days 6–13) with pregabalin groups receiving one water and one pregabalin bottle, and forced abstinence (days 14–21) with free water access. On day 13, the first open field test was conducted, followed by the Novel Object Recognition Test. On day 21, the second open field test was performed, followed by the Tail Suspension Test and Forced Swimming Test. Pregabalin elicited voluntary drinking in the higher-dose group, concurrently causing a decline in recognition memory performance in the novel object recognition test. Moreover, pregabalin induced withdrawal behavior after a period of forced abstinence in the forced swimming and tail suspension tests. This is the first report to establish an animal model of free-choice pregabalin drinking that may be used for further molecular studies and targeted therapy for pregabalin addiction

The Possible Relationship between the Abuse of Tobacco, Opioid, or Alcohol with COVID-19

Introduction: Substance use disorder has been frequently reported to increase the risk of infectious diseases, which might be owing to the sharing of contaminated inhalation, smoking, vaping, or injection equipment. Aim: This review analyzes the recent literature with the aim to put in light the possible relationship between the abuse of different substances (Tobacco, opioid, and Alcohol) with coronavirus disease (COVID-19). Tobacco: Multiple studies confirmed that cigarette smoking affects the respiratory system by increasing the expression of angiotensin-converting enzyme-2 (ACE2) receptors, which have a significant association with COVID-19 infection rate and disease severity. Opioid: Studies conducted regarding the association of opioid use disorder (OUD) and COVID-19 infection severity are limited; however, opioids can lead to both respiratory depression and kidney injuries, causing poor prognosis for those with COVID-19 infections. Alcohol: People with alcohol use disorders are at risk of developing acute lung injury and severe COVID-19 infection. Alcohol consumption during the COVID-19 pandemic has two possible scenarios: either increased or decreased based on situations. Conclusion: SUD has been frequently reported to have a positive relationship with COVID-19 severity Further studies are needed to understand the effects of opioids and alcohol abuse on COVID-19

Effects of ceftriaxone on glial glutamate transporters in Wistar rats administered sequential ethanol and methamphetamine

Methamphetamine (METH) is one of the psychostimulants that is co-abused with ethanol. Repeated high doses of METH have been shown to cause increases in extracellular glutamate concentration. We have recently reported that ethanol exposure can also increase the extracellular glutamate concentration and downregulate glutamate transporter subtype 1 (GLT-1). GLT-1 is a glial transporter that regulates the majority of extracellular glutamate. A Wistar rat model of METH and ethanol co-abuse was used to examine the expression of GLT-1 as well as other glutamate transporters (xCT and GLAST). We also examined the body temperature in rats administered METH, ethanol or both drugs. We further investigated the effects of ceftriaxone (CEF), a β-lactam antibiotic known to upregulate GLT-1, in this METH/ethanol co-abuse rat model. After seven days of either ethanol (6 g/kg) or water oral gavage, Wistar rats received either saline or METH (10 mg/kg i.p. every 2 hrs x 4), followed by either saline or CEF (200 mg/kg) posttreatment. METH administered alone decreased GLT-1 expression in the NAc and PFC and increased body temperature, but did not reduce either xCT or GLAST expression in ethanol and water-pretreated rats. Interestingly, ethanol and METH were found to have an additive effect on the downregulation of GLT-1 expression in the NAc but not in the PFC. Moreover, ethanol alone caused GLT-1 downregulation in the NAc and elevated body temperature compared to control. Finally, CEF posttreatment significantly reversed METH-induced hyperthermia, restored GLT-1 expression, and increased xCT expression. These findings suggest the potential therapeutic role of CEF against METH- or ethanol/METH-induced hyperglutamatergic state and hyperthermia