Pharmacotheraphy for Alzheimer's disease

Acute MDMA and Nicotine Co-administration: Behavioral Effects and Oxidative Stress Processes in Mice

3,4-Methylenedioxy-methylamphetamine (MDMA), a synthetic substance commonly known as ecstasy, is a worldwide recreational drug of abuse. As MDMA and nicotine activate the same neuronal pathways, we examined the influence of co-administration of nicotine (0.05 mg/kg) and MDMA (1 mg/kg) on cognitive processes, nicotine-induced behavioral sensitization and on processes linked with oxidative stress and α7 nicotinic acetylcholine receptors (nAChRs) expression in the brain of male Swiss mice. For behavioral study the passive avoidance (PA) test and locomotor sensitization paradigm were used. Also, the oxidative stress parameters as well as expression levels of α7 nAChRs in prefrontal cortex and hippocampus of mice treated with MDMA alone or in combination with nicotine were assessed. The results revealed that MDMA injections as well as co-administrations of MDMA and nicotine improved memory consolidation in male Swiss mice tested in PA task. Furthermore, one of the main findings of the present study is that MDMA increased locomotor activity in nicotine-sensitized mice. Our study showed for the first time strong behavioral and biochemical interactions between nicotine and MDMA. Both drugs are very often used in combination, especially by young people, thus these results may help explaining why psychoactive substances are being co-abused and why this polydrug administration is still a social problem.

Effects of imperatorin on scopolamine-induced cognitive impairment and oxidative stress in mice

RATIONALE

Imperatorin, a naturally occurring furanocoumarin, inactivates gamma-aminobutyric acid transaminase and inhibits acetylcholinesterase activity.

OBJECTIVES

The purpose of our experiment was to examine the influence of imperatorin on cognitive impairment and oxidative stress in the brain induced by scopolamine in male Swiss mice.

METHODS

In the present studies, we used scopolamine-invoke memory deficit measured in passive avoidance (PA) paradigm as an animal model of Alzheimer disease (AD).

RESULTS

Our finding revealed that imperatorin administered acutely at the doses of 5 and 10 mg/kg prior to the injection of scopolamine (1 mg/kg) improved memory acquisition and consolidation impaired by scopolamine. Furthermore, repeatable (7 days, twice daily) administration of the highest dose of imperatorin (10 mg/kg) significantly attenuated the effects of scopolamine on memory acquisition, whereas the doses of 5 and 10 mg/kg of this furanocoumarin were effective when memory consolidation was measured. Imperatorin, administered with scopolamine, increased antioxidant enzymes activity and decreased concentration of malondiamide, an indicator of lipid peroxidation level.

CONCLUSIONS

These results demonstrate that imperatorin may offer protection against scopolamine-induced memory impairments and possesses antioxidant properties, thus after further preclinical and clinical studies this compound may provide an interesting approach in pharmacotherapy, as well as prophylactics of AD.

Effects of imperatorin on nicotine-induced anxiety- and memory-related responses and oxidative stress in mice

The purpose of the reported experiments was to examine the effects of imperatorin [9-[(3-methylbut-2-en-1-yl)oxy]-7H-furo[3,2-g]chromen-7-one] on anxiety and memory-related responses induced by nicotine in mice and their relation to the level of nicotine-induced oxidative stress in brain as well as in the hippocampus and the prefrontal cortex. Male Swiss mice were tested for anxiety in the elevated plus maze test (EPM), and for cognition using passive avoidance (PA) procedures. Imperatorin, purified by high-speed counter-current chromatography from methanol extract of fruits of Angelica officinalis, acutely administered at the doses of 10 and 20mg/kg impaired the anxiogenic effect of nicotine (0.1mg/kg, s.c.). Furthermore, acute injections of subthreshold dose of imperatorin (1mg/kg, i.p.) improved processes of memory acquisition when co-administered with nicotine used at non-active dose of 0.05 mg/kg, s.c. Additionally, repeated administration of imperatorin (1mg/kg, i.p., twice daily, for 6 days) improved different stages of memory processes (both acquisition and consolidation) when injected in combination with non-active dose of nicotine (0.05 mg/kg, s.c.) in the PA task. Oxidative stress was assessed by determination of antioxidant enzymes (glutathione peroxidases (GPx), superoxide dismutase (SOD), glutathione reductase (GR)) activities as well as of malondialdehyde (MDA) concentration in the whole brain, the hippocampus and the prefrontal cortex after repeated administration of imperatorin (1mg/kg, 6 days) and single nicotine injection (0.05 mg/kgs.c.) on the seventh day. The results of our research suggest strong behavioural interaction between imperatorin and nicotine at the level of anxiety- and cognitive-like processes. Furthermore, imperatorin inhibited nicotine-induced changes in examined indicators of oxidative stress, especially in the hippocampus and the cortex.

Memory-related effects of cholinergic receptor ligands in mice as measured by the elevated plus maze test

The purpose of our experiments was to examine the influence of cholinergic receptor ligands on memory-related behavior in mice using the elevated plus maze (EPM) test. The EPM test allows the exploration of different memory processes (acquisition and consolidation), depending on the time of drug treatment. The time necessary for mice to move from the opened arm to the enclosed arm (i.e., transfer latency, TL) was used as an index of memory. Our findings reveal that for both the processes of acquisition and consolidation, treatment with nicotine (0.035 or 0.175 mg/kg, free base, sc) shortened TL on the second day of the experiments (TL2), thus improving memory processes. Treatment with scopolamine (0.3 or 1.0 mg/kg, ip) significantly increased TL2 values, thus impairing cognitive processes. Moreover, we found that treatment with nicotine, at the non-effective doses used during testing, prevented scopolamine-induced memory impairment by inducing a decrease in TL2 values. Next, we evaluated the influence of bupropion (10 or 20 mg/kg, ip), a drug currently used for smoking cessation in humans, on memory-related behavior induced by treatment with nicotine and scopolamine. An acute injection of bupropion (10 or 20 mg/kg) prior to injection with either nicotine (0.035 mg/kg) or scopolamine (1.0 mg/kg) significantly prevented nicotine-induced memory improvement or scopolamine-induced memory impairment. Bupropion treatment can diminish the rewarding (dependence-producing) effects of nicotine and also the cognitive effects that are related to addiction. Our studies further indicate the great involvement of the cholinergic system in memory processes and the potential for the development of more effective pharmacotherapies for memory impairment-like human disorders in which the cholinergic pathways have been implicated.

Multiplexed quantification of dementia biomarkers in the CSF of patients with early dementias and MCI: a multicenter study

In this report we evaluated the clinical performance of APOE genotyping and three protein biomarkers (total tau, beta-amyloid(1-42), and tau phosphorylated at threonine 181) in a prospective multicenter study using the INNO-BIA AlzBio3 assay applied on Luminex platform. Concentration of biomarkers of Alzheimer's disease in cerebrospinal fluid (CSF) was measured with multiplexing technology (n=223), and compared to the results of ELISA assays in patients with early dementias or mild cognitive impairment (MCI) collected at 12 gerontopsychiatric university departments, and APOE genotyping was performed. Concentrations of Abeta(1-42) were statistically significantly lower in MCI-AD subjects compared to MCI-O, and significantly lower in D-AD patients compared to MCI-O. P-tau(181P) concentrations were significantly higher in MCI-AD patients compared to MCI-O, and significantly higher in D-AD patients compared to MCI-O. The total tau concentrations in MCI-AD patients were significantly higher compared to MCI-O, and higher in D-AD compared to MCI-O, moreover, the concentration of total tau was significantly higher in D-AD compared to MCI-AD patients. For the differential diagnosis between D-AD and D-O, the optimal cutoff concentration of Abeta(1-42) was 197.7 pg/mL, and that for P-tau(181P) was 47.9 pg/mL. These cutoff values were also applied to discriminate between MCI-AD and MCI-O subjects. Simultaneous measurement of the biomarkers significantly improves management of the samples and quality control of the assays' performance.

The German Competence Net Dementias: Standard operating procedures for the neurochemical dementia diagnostics

Aging of population results in an increasing number of patients with dementia. Therefore, recently a BMBF-supported project, Competence Net Dementia, was launched to reveal diagnostic, therapeutic, and epidemiologic aspects of demential disorders. In this project, our task was to establish and maintain human body fluids (HBF) bank to collect cerebrospinal fluid, plasma, serum, and full blood of patients enrolled into the study. As the pre-analytical sample handling is a prerequisite of all studies aiming at finding novel disease biomarkers, standard operating procedures (SOPs) were launched by our group to allow standardized collection, storage, and shipment of the samples among all 14 University centers involved in HBF collection. Currently, to our best knowledge the CND HBF bank represents one of the largest prospectively collected set of the samples from subjects with mild cognitive impairment and early dementias. With the samples collected in the HBF bank, recently introduced analytical technologies (like e.g. surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS), differential gel electrophoresis (DIGE), and multiplexing) can be promptly tested with regard to their potential usefulness in neurochemical dementia diagnostics.

Consensus paper of the WFSBP Task Force on Biological Markers of Dementia: the role of CSF and blood analysis in the early and differential diagnosis of dementia

Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimer's disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Abeta peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.

Antioxidant treatment in Alzheimer's disease: current state

Accumulating data from experimental and human studies indicate that oxidative stress (OS) plays a major role in the pathogenesis of Alzheimer's disease (AD). The production of reactive oxygen species (ROS), which leads to OS, can occur very early, even before the appearance of symptoms and molecular events (beta-amyloid plaques and neurofibrillary tangles), leading to tissue damage via several different cellular molecular pathways. ROS can cause damage to cardinal cellular components such as lipids, proteins, and nucleic acids (e.g., RNA, DNA), causing cell death by modes of necrosis or apoptosis. The damage can become more widespread because of the weakened cellular antioxidant defense systems. Therefore, treatment with antioxidants might theoretically act to prevent propagation of tissue damage and improve both survival and neurological outcome. Indeed, several studies preformed to date examined whether dietary intake of several antioxidants, mainly vitamins, might prevent or reduce the progression of AD. Although a few of the antioxidants showed some efficacy in these trials, no answer is yet available as to whether antioxidants are truly protective against AD. Reasons for these results might include, in part, blood-brain barrier (BBB) permeability, inappropriate timing of administration, or suboptimal drug levels at the target site in the central nervous system. Thus, antioxidant cocktails or antioxidants combined with other drugs may have more successful synergistic effects. Further, well-designed intervention, as well as observational investigations based on large cohorts studied over a long period of time with several methods for assessing antioxidant exposure, including relation to BBB penetration, are needed to test this hypothesis.

Stroke, dementia, and drug delivery

Stroke and dementia represent a major health burden for elderly subjects as they are associated with significant morbidity and mortality. The rates of stroke and dementia are progressively increasing due to the ageing population in most westernized countries. Therefore, both these conditions represent a major therapeutic target. However, the therapeutic options available for the management of stroke and dementia remain largely unsatisfactory, the main reason being the difficulty in transferring the results obtained in animal and in vitro studies to the clinical setting. This review focuses on the recent advances in pathophysiology and treatment of these conditions and future directions for research. Moreover, the technique of functional magnetic resonance imaging is discussed in detail as a tool to assess the effects of therapeutic agents on the central nervous system and monitor the progression of diseases. Finally, an overview of the issue of drug delivery into the central nervous system is presented.

Activation of Stat3 by receptor tyrosine kinases and cytokines regulates survival in human non-small cell carcinoma cells

Overexpression of receptor tyrosine kinases including the epidermal growth factor receptor (EGF-R) as well as nonreceptor tyrosine kinases, such as Src, have been implicated in the formation of human lung cancers. In addition, cytokines like interleukin-6 (IL-6) have been demonstrated to modulate lung cancer cell growth and elevated levels of IL-6 have been shown to be an adverse prognostic factor for patients with lung cancer. Despite a large body of evidence pointing to their potential importance, few direct studies into the role of signal transducers and activators of transcription (STAT) pathways in human lung cancer have been undertaken. Here we demonstrate that multiple nonsmall cell lung cancer cell lines demonstrate constitutive Stat3 DNA-binding activity. Stat3 DNA-binding activity is specifically upregulated by the addition of epidermal growth factor (EGF), IL-6, and hepatocyte-derived growth factor (HGF). Furthermore, the stimulation of Stat3 DNA-binding activity by EGF requires the activity of EGF-R tyrosine kinase as well as Src-kinase, while the upregulation of Stat3 activity by IL-6 or HGF requires only Src-kinase activity. Treatment of A549 lung cancer cells with PD180970 or SU6656, both pharmacological inhibitors of Src-kinase, resulted in reduced Src and Stat3 activity, cell cycle arrest in G2, and reduced viability of cells accompanied by induction of apoptosis. Treatment of Stat3-positive A549 and H358 cells with antisense Stat3 oligonucleotides results in complete loss of Stat3 DNA-binding activity and apoptosis, while Stat3-positive H1299 cells remained healthy. Finally, an adenoviral vector expressing a dominant-negative Stat3 isoform results in loss of Stat3 DNA-binding activity, apoptosis, and reduced cellular viability. These results demonstrate a role of Stat3 in transducing survival signals downstream of tyrosine kinases such as Src, EGF-R, and c-Met, as well as cytokines such as IL-6, in human nonsmall cell lung cancers.