Treating Alzheimer's disease using nanoparticle-mediated drug delivery strategies/systems.

The administration of promising medications for the treatment of neurodegenerative disorders (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) is significantly hampered by the blood-brain barrier (BBB). Nanotechnology has recently come to light as a viable strategy for overcoming this obstacle and improving drug delivery to the brain. With a focus on current developments and prospects, this review article examines the use of nanoparticles to overcome the BBB constraints to improve drug therapy for AD The potential for several nanoparticle-based approaches, such as those utilizing lipid-based, polymeric, and inorganic nanoparticles, to enhance drug transport across the BBB are highlighted. To shed insight on their involvement in aiding effective drug transport to the brain, methods of nanoparticle-mediated drug delivery, such as surface modifications, functionalization, and particular targeting ligands, are also investigated. The article also discusses the most recent findings on innovative medication formulations encapsulated within nanoparticles and the therapeutic effects they have shown in both preclinical and clinical testing. This sector has difficulties and restrictions, such as the need for increased safety, scalability, and translation to clinical applications. However, the major emphasis of this review aims to provide insight and contribute to the knowledge of how nanotechnology can potentially revolutionize the worldwide treatment of NDDs, particularly AD, to enhance clinical outcomes.

Role of Deployment History on the Association Between Epilepsy and Traumatic Brain Injury in Post-9/11 Era US Veterans.

BACKGROUND AND OBJECTIVES: Traumatic brain injury (TBI) is a well-established epilepsy risk factor and is common among service members. Deployment-related TBI, where combat/blast may be more common, may have different outcomes than nondeployment-related TBI. This work examined associations of all TBI exposures (not just combat), and epilepsy, while adjusting for comorbidities associated with epilepsy, among veterans by deployment status. METHODS: The cohort included post-9/11 veterans with ≥2 years of care in both Veterans Health Administration and Defense Health Agency systems. We identified epilepsy using ICD-9/10-CM codes, antiseizure medication, and service-connected disability for epilepsy. We conducted a logistic regression model with interaction terms for conditions by deployment history that adjusted for demographics and military characteristics. RESULTS: The cohort (n = 938,890) included post-9/11 veterans of whom 27,436 (2.92%) had epilepsy. Most veterans had a history of deployment (70.64%), referred to as "deployed." Epilepsy was more common among veterans who were never deployed ("nondeployed") (3.85% vs 2.54%). Deployed veterans were more likely to have had TBI, compared with the nondeployed veterans (33.94% vs 14.24%), but nondeployed veterans with moderate/severe TBI had higher odds of epilepsy compared with deployed veterans (adjusted odds ratio [aOR] 2.92, 95% CI 2.68-3.17 vs aOR 2.01, 95% CI 1.91-2.11). Penetrating TBI had higher odds of epilepsy among the deployed veterans (aOR 5.33, 95% CI 4.89-5.81), whereas the odds of epilepsy for mild TBI did not significantly differ by deployment status. Although most neurologic conditions were more prevalent among the nondeployed veterans, they were often associated with higher odds of epilepsy in the deployed veterans. DISCUSSION: Deployment history had a significant differential impact on epilepsy predictors. As expected, penetrating TBI had a greater epilepsy impact among deployed veterans perhaps due to combat/blast. Some epilepsy predictors (moderate/severe TBI, multiple sclerosis, and Parkinson disease) had a stronger association in the nondeployed veterans suggesting a potential healthy warrior effect in which such conditions preclude deployment. Other neurologic conditions (e.g., brain tumor, Alzheimer disease/frontotemporal dementia) had a greater epilepsy impact in the deployed veterans. This may be attributable to deployment-related exposures (combat injury, occupational exposures). A better understanding of deployment effects is critical to provide targeted epilepsy prevention in veterans and military service members.

Veteran perspectives of epilepsy care: Impact of Veteran satisfaction, knowledge, and proactivity.

OBJECTIVE: Veterans are at elevated risk of epilepsy due to higher rates of traumatic brain injury (TBI). However, little work has examined the extent to which quality of care is associated with key outcomes for Veterans with epilepsy (VWE). This study aimed to examine the impact of quality of care on three outcomes: patients' knowledge of epilepsy self-care, proactive epilepsy self-management, and satisfaction with care. METHOD: We conducted a cross-sectional study of Post-9/11 Veterans with validated active epilepsy who received VA care (n = 441). Veterans were surveyed on care processes using American Academy of Neurology epilepsy quality measures, and a patient-generated measure related to the use of emergency care. Outcome measures included epilepsy self-care knowledge, proactive epilepsy self-management, and satisfaction with epilepsy care. Covariates included sociodemographic and health status variables and a measure of patient-provider communication. An ordinary least-squares (OLS) regression model was used to determine if the quality of care was associated with the outcomes adjusting for multiple comparisons. RESULTS: Self-reported measures of quality of care were broadly associated with satisfaction with care and epilepsy knowledge. OLS modeling indicated that healthcare provider guidance on when to seek emergency care was significantly associated with higher Veteran satisfaction with care (p < 0.01). Veterans who were asked about seizure frequency at every visit by their provider also reported higher satisfaction with care (p < 0.01) and increased epilepsy knowledge (p < 0.01). Veteran-provider communication was positively associated with epilepsy knowledge and proactive epilepsy self-management. Veterans with epilepsy with drug resistance epilepsy were significantly less satisfied with their care and reported lower proactivity compared to epilepsy controlled with medications. Further analysis indicated Black VWEs reported lower scores on epilepsy self-care knowledge compared to Whites (p < 0.001). CONCLUSIONS: This study found that quality measures were associated with satisfaction and epilepsy knowledge but not associated with proactive self-management in multivariable models. The finding that better communication between providers and Veterans suggests that in addition to technical quality, interpersonal quality is important for patient outcomes. The secondary analysis identified racial disparities in epilepsy knowledge. This work offers opportunities to improve the quality of epilepsy care through the practice of patient-centered care models that reflect Veteran priorities and perceptions.

COVID-19 pandemic experiences among people with epilepsy: Effect on symptoms of co-occurring health conditions and fear of seizure.

OBJECTIVE: The Coronavirus disease 2019 (COVID-19) pandemic profoundly affected people worldwide, but little is known about how it impacted people with epilepsy (PWE). We examined the associations between COVID-19 stressors and health outcomes including increases in other health symptoms and fear of seizure among PWE. METHODS: This cross-sectional study used data from an online survey that asked about demographic characteristics, health conditions, and potential life stressors during COVID-19. Data were collected from October 30 to December 8, 2020. COVID-19 stressors were anger, anxiety, stress, healthcare access, fear of seeking healthcare, social isolation, sense of control over their lives, and alcohol consumption. A binary variable was created for each of these measures to indicate whether PWEs experienced a negative change versus a neutral or positive change. We used multivariable logistic regression to assess the associations of COVID-19 stressors with primary outcomes: exacerbated co-occurring health conditions and increasing fear of seizure during the pandemic. RESULTS: Of the 260 PWE included in the study, 165 (63.5%) were women; the average age was 38.7 years. During the survey administration period, 79 (30.3%) of the respondents reported exacerbated co-occurring health conditions, and 94 (36.2%) reported an increased fear of seizures. Regression results indicated that the fear of seeking healthcare during COVID-19 was associated with both exacerbated co-occurring health conditions (aOR 1.12; 95%CI 1.01-1.26) and increasing fear of seizure (aOR 2.31; 95%CI 1.14-4.68). Social isolation was associated with exacerbated co-occurring health conditions during COVID-19 (aOR 1.14; 95%CI 1.01-1.29). Reduced access to physical healthcare was associated with increasing fear of seizure (aOR 2.58; 95%CI 1.15-5.78). CONCLUSION: A considerable number of PWE experienced more symptoms of existing health conditions and fear of seizure during the initial year of the pandemic (2020). Fear of seeking healthcare services was associated with both negative outcomes. Assuring access to health care and reducing social isolation could potentially reduce negative outcomes for PWE. It is necessary to provide adequate support for PWE to reduce risks as COVID-19 continues to be a health concern.

Caregiver burden and COVID-19: How epilepsy caregivers experienced the pandemic.

INTRODUCTION: Caregivers of adults with epilepsy face unique challenges, yet most studies focus on the impact of epilepsy on those living with the condition, rather than the impact on caregivers. Our objective was to evaluate whether caregivers' pandemic-related changes and experiences - namely those related to their health, healthcare access, and well-being - were associated with their caregiving burden. METHODS: Caregivers of adults with epilepsy (n = 261) were recruited through Qualtrics Panels to participate in an online survey examining health, well-being, COVID-19 experiences, and caregiver burden from October-December, 2020. The burden was measured using the Zarit 12-item measure; the clinically significant burden was defined as a score greater than 16. Adjustments were made to account for burden scores related to exposures of interest. Chi-square tests, t-tests, and generalized linear regression models were used to compare cross-sectional associations between COVID-19 experiences and burden. RESULTS: Over half (57.9%) of caregivers had clinically significant caregiver burden. Most reported increased anxiety (65%), stress (64%), and sense of social isolation (58%) during the pandemic. Many caregivers reported that their sense of control over their life (44%) and their use of healthcare changed (88%) due to COVID-19. In adjusted models, caregivers who reported increased anger, increased anxiety, decreased sense of control, or changes in healthcare utilization during COVID-19 had about twice the odds of having clinically significant caregiver burden compared to caregivers who did not report changes. DISCUSSION: Changes experienced by caregivers of adults with epilepsy during the pandemic were strongly associated with clinically significant levels of caregiver burden. These findings demonstrate the link between mass-level events, such as a pandemic, the burden caregivers of adults with epilepsy may carry, and subsequent psychological outcomes. CONCLUSION: Caregivers of adults with epilepsy may need support to reduce the negative impact of COVID-19-related experiences and should be connected to healthcare and resources that can help alleviate their burden.

Multimodal Quality of Life Assessment in Post-9/11 Veterans With Epilepsy: Impact of Drug Resistance, Traumatic Brain Injury, and Comorbidity.

BACKGROUND AND OBJECTIVES: Epilepsy is defined by the occurrence of multiple unprovoked seizures, but quality of life (QOL) in people with epilepsy is determined by multiple factors, in which psychiatric comorbid conditions play a pivotal role. Therefore, understanding the interplay between comorbid conditions and QOL across epilepsy phenotypes is an important step toward improved outcomes. Here, we report the impact of QOL across distinct epilepsy phenotypes in a cohort of post-9/11 veterans with high rates of traumatic brain injury (TBI). METHODS: This observational cohort study from the Veterans Health Administration included post-9/11 veterans with epilepsy. A process integrating an epilepsy identification algorithm, chart abstraction, and self-reported measures was used to classify patients into 1 of 4 groups: (1) epilepsy controlled with medications, (2) drug-resistant epilepsy (DRE), (3) posttraumatic epilepsy (PTE), or (4) drug-resistant PTE (PT-DRE). Summary scores for 6 QOL measures were compared across the groups after adjustment for age, sex, and number of comorbid conditions. RESULTS: A total of 529 survey respondents with epilepsy were included in the analysis: 249 controls (i.e., epilepsy without DRE or PTE), 124 with DRE, 86 with PTE, and 70 with PT-DRE. DRE was more common in those with PTE compared with those with nontraumatic epilepsy (45% vs 33%, odds ratio 1.6 [95% CI 1.1-2.4], p = 0.01). Patients with PTE and PT-DRE had significantly more comorbid conditions in health records than those with nontraumatic epilepsy. Those with both PTE and DRE reported the lowest QOL across all 6 measures, and this persisted after adjustment for comorbid conditions and in further linear analyses. DISCUSSION: Among those with PTE, DRE prevalence was significantly higher than prevalence of nontraumatic epilepsies. PTE was also associated with higher burden of comorbidity and worse overall QOL compared to nontraumatic epilepsies. People with PTE are distinctly vulnerable to the comorbid conditions associated with TBI and epilepsy. This at-risk group should be the focus of future studies aimed at elucidating the factors associated with adverse health outcomes and developing antiepileptogenic therapies.

Military Injuries-Understanding Posttraumatic Epilepsy, Health, and Quality-of-Life Effects of Caregiving: Protocol for a Longitudinal Mixed Methods Observational Study.

BACKGROUND: Veterans with posttraumatic epilepsy (PTE), particularly those with comorbidities associated with epilepsy or traumatic brain injury (TBI), have poorer health status and higher symptom burden than their peers without PTE. One area that has been particularly poorly studied is that of the role of caregivers in the health of veterans with PTE and the impact caring for someone with PTE has on the caregivers themselves. OBJECTIVE: In this study, we aim to address the following: describe and compare the health and quality of life of veterans and caregivers of veterans with and without PTE; evaluate the change in available supports and unmet needs for services among caregivers of post-9/11 veterans with PTE over a 2-year period and to compare support and unmet needs with those without PTE; and identify veteran and caregiver characteristics associated with the 2-year health trajectories of caregivers and veterans with PTE compared with veterans without PTE. METHODS: We conducted a prospective cohort study of the health and quality of life among 4 groups of veterans and their caregivers: veterans with PTE, nontraumatic epilepsy, TBI only, and neither epilepsy nor TBI. We will recruit participants from previous related studies and collect information about both the veterans and their primary informal caregivers on health, quality of life, unmet needs for care, PTE and TBI symptoms and treatment, relationship, and caregiver experience. Data sources will include existing data supplemented with primary data, such as survey data collected at baseline, intermittent brief reporting using ecological momentary assessment, and qualitative interviews. We will make both cross-sectional and longitudinal comparisons, using veteran-caregiver dyads, along with qualitative findings to better understand risk and promotive factors for quality of life and health among veterans and caregivers, as well as the bidirectional impact of caregivers and care recipients on one another. RESULTS: This study was approved by the institutional review boards of the University of Utah and Salt Lake City Veterans Affairs and is under review by the Human Research Protection Office of the United States Army Medical Research and Development Command. The Service Member, Veteran, and Caregiver Community Stakeholders Group has been formed and the study questionnaire will be finalized once the panel reviews it. We anticipate the start of recruitment and primary data collection by January 2022. CONCLUSIONS: New national initiatives aim to incorporate the caregiver into the veteran's treatment plan; however, we know little about the impact of caregiving-both positive and negative-on the caregivers themselves and on the veterans for whom they provide care. We will identify specific needs in this understudied population, which will inform clinicians, patients, families, and policy makers about the specific impact and needs to equip caregivers in caring for veterans at home. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/30975.

The relationship between macro-socioeconomics determinants and COVID-19 vaccine distribution.

Since coronavirus disease 2019 (COVID-19) has continued to spread globally, many countries have started vaccinations at the end of December 2020. This research examines the relationship between COVID-19 vaccine distribution and two macro-socioeconomics measures, including human development index and gross domestic product, among 25 countries for two points in time, including February and August 2021. The COVID-19 dataset is a collection of the COVID-19 data maintained by Our World in Data. It is a daily updated dataset and includes confirmed cases, vaccinations, deaths, and testing data. Ordinary Least Squares was applied to examine how macro-socioeconomic measures predict the distribution of the COVID-19 vaccine over time. RESULTS: The results indicate that a higher gross domestic product per capita is positively associated with higher COVID-19 vaccine distribution, and this relationship becomes more robust over time. However, some countries may have more successful vaccine distribution results regardless of their gross domestic product. In addition, the result shows human development index does not have a significant relationship with vaccine distribution. CONCLUSION: Economic measures may be counted as a more vital indicator for vaccine distribution as they have a more direct relationship distribution with health infrastructure than social measures such as human development index.

The Influence of COVID-19 Vaccination on Daily Cases, Hospitalization, and Death Rate in Tennessee, United States: Case Study.

BACKGROUND: The COVID-19 outbreak highlights our vulnerability to novel infections, and vaccination remains a foreseeable method to return to normal life. However, infrastructure is inadequate for the immediate vaccination of the whole population. Therefore, policies have adopted a strategy to vaccinate older adults and vulnerable populations while delaying vaccination for others. OBJECTIVE: This study aimed to understand how age-specific vaccination strategies reduce daily cases, hospitalizations, and death rates using official statistics for Tennessee, United States. METHODS: This study used publicly available data on COVID-19, including vaccination rates, positive cases, hospitalizations, and deaths from the Tennessee Department of Health. Data from the first date of vaccination (December 17, 2020) to March 3, 2021, were retrieved. The rates were adjusted by 2019 data from the US Census Bureau, and age groups were stratified into 10-year intervals starting with 21 years of age. RESULTS: The findings showed that vaccination strategy can reduce the numbers of patients with COVID-19 in all age groups, with lower hospitalization and death rates in older populations. Older adults had a 95% lower death rate from December to March; no change in the death rate of other age groups was observed. The hospitalization rate was reduced by 80% for people aged ≥80 years, while people who were 50 to 70 years old had nearly the same hospitalization rate as prior to vaccination. CONCLUSIONS: This research indicates that targeting older age groups for vaccination is the optimal way to avoid higher transmissions and reduce hospitalization and death rates.

Racial and Gender-Based Differences in COVID-19.

The novel coronavirus disease (COVID-19) has become a global health crisis since its first appearance in Wuhan, China. Current epidemiological studies suggest that COVID-19 affects older patients with multiple comorbidities, such as hypertension, obesity, and chronic lung diseases. The differences in the incidence and severity of COVID-19 are likely to be multifaceted, depending on various biological, social, and economical factors. Specifically, the socioeconomic differences and psychological impact of COVID-19 affecting males and females are essential in pandemic mitigation and preparedness. Previous clinical studies have shown that females are less susceptible to acquire viral infections and reduced cytokine production. Female patients have a higher macrophage and neutrophil activity as well as antibody production and response. Furthermore, in-vivo studies of the angiotensin-converting enzyme 2 (ACE2) showed higher expression in the kidneys of male than female patients, which may explain the differences in susceptibility and progression of COVID-19 between male and female patients. However, it remains unknown whether the expression of ACE2 differs in the lungs of male or female patients. Disparities in healthcare access and socioeconomic status between ethnic groups may influence COVID-19 rates. Ethnic groups often have higher levels of medical comorbidities and lower socioeconomic status, which may increase their risk of contracting COVID-19 through weak cell-mediated immunity. In this article, we examine the current literature on the gender and racial differences among COVID-19 patients and further examine the possible biological mechanisms underlying these differences.

New systematically modified vesamicol analogs and their affinity and selectivity for the vesicular acetylcholine transporter - A critical examination of the lead structure.

To verify vesamicol as lead structure in the development of radioligands for imaging of VAChT in the brain by PET, we systematically modified this molecule and investigated four different groups of derivatives. Structural changes were conducted in all three ring systems A, B, and C resulting in a library of different vesamicol analogs. Based on their in vitro binding affinity toward VAChT as well as σ1 and σ2 receptors, we performed a structure-affinity relationship (SAR) study regarding both affinity and selectivity. The compounds possessed VAChT affinities in the range of 1.32 nM (benzovesamicol) to >10 µM and selectivity factors from 0.1 to 73 regarding σ1 and σ2 receptors, respectively. We could confirm the exceptional position of benzovesamicols as most affine VAChT ligands. However, we also observed that most of the compounds with high VAChT affinity demonstrated considerable affinity in particular to the σ1 receptor. Finally, none of the various vesamicol analogs in all four groups showed an in vitro binding profile suitable for specific VAChT imaging in the brain.

The role of nitric oxide in the PKA inhibitor induced spatial memory deficits in rat: involvement of choline acetyltransferase.

Several lines of evidence show that cAMP-PKA signaling pathway plays critical role in memory functions and suggest nitric oxide as an important modulator in learning and memory. In this study, we assessed the effects of intra-hippocampal infusion of H-89, a selective PKAII inhibitor, and 1400 W, a selective inducible nitric oxide synthase (iNOS) inhibitor, on spatial memory in rats. By using the Morris water maze, spatial memory retention parameters were examined 48 h after the infusions through measuring escape latency, traveled distance, and swimming speed. The rats receiving intra-hippocampal infusions of 1400 W (100 µM/side) showed a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the control saline group. In contrast, a significant increase (**P<0.01) in escape latency and traveled distance was observed after infusion of 10 µM H-89. Moreover, among combination groups, co-administration of 1400 W (400 µM/side) with 10 µM/side of H-89 caused a significant reduction (*P<0.05) in escape latency and traveled distance in comparison with the H-89 group. Also, we evaluated the molecular effects of 1400 W on the expression of choline acetyltransferase (ChAT), a cholinergic marker, in the CA1 region of the hippocampus and medial septal area (MSA). Immunohistochemical analysis of post-training bilateral intra-hippocampal infusion of 1400 W revealed a significant increase in ChAT immunoreactivity levels in both the CA1 and the MSA regions. Overall, the results suggest that 1400 W has protective effect against H89-induced spatial memory impairment. Moreover, the observed memory improvements caused by 1400 W infusions, might be due to interaction of iNOS with the cholinergic system.

Effects of protein kinase A and G inhibitors on hippocampal cholinergic markers expressions in rolipram- and sildenafil-induced spatial memory improvement.

Although there are number of studies showing that phosphodiesterase (PDE) 4 and 5 inhibitors affect different kinds of memory, their effects on spatial memory consolidation in conjunction with the cholinergic activity in the hippocampus have not been studied before. In the present study firstly, rats were evaluated for the effects of different doses of the PDE4 inhibitor rolipram and the PDE5 inhibitor sildenafil on spatial memory consolidation in the water maze task. Rolipram or sildenafil was daily administered intraperitoneally 3 or 0 h after the last trial of training, respectively. Then in a separate related experiment the effect of the most efficient doses of rolipram or sildenafil accompanied by an intrahippocampally injected protein kinase A (PKA) or protein kinase G (PKG) inhibitor, respectively, was examined. Finally for determination of the hippocampal cholinergic activity the protein expression of hippocampal vesicular acetylcholine transporter (VAChT) and cholineacetyltransferase (ChAT) was measured. Rolipram at 0.03 mg/kg as well as sildenafil at 3 mg/kg increased spatial memory and their enhancing effect was completely blocked following inhibition of PKA and PKG, respectively. Furthermore, none of the treatments had a significant effect on the hippocampal ChAT and VAChT levels. Our data showed that rolipram and sildenafil enhanced spatial memory consolidation in an inverted U-shaped dose-response curve. This effect is dependent on the activity of cAMP/PKA- and cGMP/PKG-mediated pathways, respectively in the hippocampus. However, we did not find evidence for a chronic increase of cholinergic activity in the observed PDE inhibitor-induced memory improvement.

Interactive effects of a protein kinase AII inhibitor and testosterone on spatial learning in the Morris water maze.

Neurohormones such as testosterone (TE) are important in modulation of learning and memory. In the present study, we investigated the interactive effects of pre-training bilateral intra-hippocampal infusions of testosterone and H-89, a selective PKAII inhibitor, on spatial acquisition in the Morris water maze (MWM). Different doses of TE (20, 40 and 80 µg/side) and H-89 (5 and 10 µM/side) were administered 30 min before start of the training each day. Control animals received bilateral intra-hippocampal infusions of DMSO as vehicle for TE and H-89. Animals were trained for 4 days and each day included one block of four trials. The results of this study showed that bilateral infusion of TE (40 and 80 µg/side) or H-89 (10 µM/side) impaired spatial learning as indicated by significant increases in escape latency and traveled distance compared to the control group. Although pre-training bilateral infusions of a low concentration of either TE (20 µg/side) or H-89 (5 µM/side) into the CA1 region of the hippocampus did not affect learning capabilities, but the combination of the low doses of the drugs led to significant deficits in spatial acquisition. Overall, our data suggest that spatial acquisition was affected by PKAII inhibition or TE administration. Moreover, when co-administered, these drugs had a negative synergistic impact on acquisition.

Evaluation of systemic administration of Boswellia papyrifera extracts on spatial memory retention in male rats.

Time-dependent effects of ethanolic extract of Boswellia papyrifera, administered systemically, on spatial memory retention in the Morris water maze were investigated in male rats. A total extract of Boswellia papyrifera (300 mg/kg) was administered every eight hours to three groups of rats by gavage for 1, 2 and 4 weeks. In a separate set of experiments, three doses of a fraction of the extract, called the boswellic acids (100, 200 and 300 mg/kg) were administered by gavage to three groups of rats three times a day for 2 weeks. Following these applications, animals were trained for 4 days. Behavioral testing for evaluation of spatial memory retention was performed 48 h after completion of training. Boswellia papyrifera extracts and boswellic acids caused a significant reduction in escape latency and distance traveled but had no influence on swimming speed. These findings provide evidence that Boswellia papyrifera extracts affect spatial memory retention irrespective of the treatment period. In addition our data show that systemic administration of the boswellic acids fraction enhanced spatial memory retention in a dose-dependent manner. These improving effects may be due to some extent to the interactions of these products with inflammatory mediators, neurotransmitter signaling cascades or protein kinase pathways in the brain.

Neuroimaging of the vesicular acetylcholine transporter by a novel 4-[18F]fluoro-benzoyl derivative of 7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazines.

Phenylpiperidinyl-octahydro-benzo[1,4]oxazines represent a new class of conformationally restrained vesamicol analogues. Derived from this morpholine-fused vesamicol structure, a new fluorine-18-labeled 4-fluorobenzoyl derivative ([(18)F]FBMV) was synthesized with an average specific activity of 75 GBq/micromol and a radiochemical purity of 99%. The radiolabeling method included an exchange reaction of a 4-nitro group of the precursor by fluorine-18, a reduction procedure to eliminate excess of the nitro compound, followed by a high-performance liquid chromatography purification. [(18)F]FBMV demonstrates (i) a moderate lipophilic character with a logD(pH7.0) 1.8+/-0.10; (ii) a considerable binding affinity to the vesicular acetylcholine transporter (VAChT) (K(i)=27.5 nM), as determined using PC12 cells transfected with a VAChT cDNA, and a low affinity to sigma(1,2) receptors (K(i) >3000 nM); (iii) a good uptake into the rat and pig brains; (iv) a typical accumulation in the VAChT-containing brain regions; and (v) an approximately 20% reduction in cortical tracer binding after a specific cholinergic lesion using 192IgG-saporin. [(18)F]FBMV exhibits another PET marker within the group of vesamicol derivatives that demonstrates potentials in imaging brain cholinergic deficits, while its usefulness in clinical practice must await further investigation.

A new 18F-labeled fluoroacetylmorpholino derivative of vesamicol for neuroimaging of the vesicular acetylcholine transporter.

With the aim of producing selective radiotracers for in vivo imaging of the vesicular acetylcholine transporter (VAChT) using positron mission tomography (PET), here, we report synthesis and analysis of a new class of conformationally constrained vesamicol analogues with moderate lipophilicity. The sequential ring opening on trans-1,4-cyclohexadiene dioxide enabled an approach to synthesize 6-arylpiperidino-octahydrobenzo[1,4]oxazine-7-ols [morpholino vesamicols]. The radiosynthesis of the [18F]fluoroacetyl-substituted derivative ([18F]FAMV) was achieved starting from a corresponding bromo precursor [2-Bromo-1-[7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazin-4-yl]-ethanone] and using a modified commercial computer-controlled module system with a radiochemical yield of 27+/-4%, a high radiochemical purity (99%) and a specific activity of 35 GBq/micromol. In competitive binding assays using a PC12 cell line overexpressing VAChT and [3H]-(-) vesamicol, 2-fluoro-1-[7-hydroxy-6-(4-phenyl-piperidin-1-yl)-octahydro-benzo[1,4]oxazin-4-yl]-ethanone (FAMV) demonstrated a high selectivity for binding to VAChT (K(i): 39.9+/-5.9 nM) when compared to its binding to sigma 1/2 receptors (Ki>1500 nM). The compound showed a moderate lipophilicity (logD (pH 7)=1.9) and a plasma protein binding of 49%. The brain uptake of [18F]FAMV was about 0.1% injected dose per gram at 5 min after injection and decreased continuously with time. Notably, an increasing accumulation of radioactivity in the lateral brain ventricles was observed. After 1 h, the accumulation of [18F]FAMV, expressed as ratio to the cerebellum, was 4.5 for the striatum, 2.0 for the cortical and 1.5 for the hippocampal regions, measured on brain slices using ex vivo autoradiography. At the present time, 75% of [18F]FAMV in the plasma was shown to be metabolized to various hydrophilic compounds, as detected by high-performance liquid chromatography. The degradation of [18F]FAMV was also detected in brain extracts as early as 15 min post injection (p.i.) and increased to 50% at 1 h postinjection. In conclusion, although the chemical properties of [18F]FAMV and the selectivity of binding to VAChT appear to be promising indicators of a useful PET tracer for imaging VAChT, a low brain extraction, in combination with only moderate specific accumulation in cholinergic brain regions and an insufficient in vivo stability prevents the application of this compound for neuroimaging in humans.

Systemic and developmental exposure to lead causes spatial memory deficits and a reduction in COX-2 immunoreactivity in the hippocampus of male rats.

Chronic lead exposure during development is known to produce learning deficits. In the present study, we investigated the effects of developmental exposure to lead on spatial memory, as shown in the Morris water maze, and on expression of inducible cyclooxygenase-2 protein in the hippocampi of male rats. Rats were separated into four groups according to which concentration of lead acetate at which developmental stage they were exposed. One group was exposed maternally to lead acetate at a concentration of 250 parts per million (ppm), one group was exposed continuously to 250 ppm lead, one group was exposed maternally to 750 ppm lead, and one group was exposed continuously to 750 ppm lead. Increases were observed in both average escape latency and traveled distance of the rats in the maternally and continuously 750 ppm lead-exposed groups, indicating significant impairment of spatial memory. Quantitative immunostaining analysis by optical density measurement of brain sections from rats in all lead-exposed groups revealed a significant reduction (P < 0.001) in the intensity of cyclooxygenase-2 immunoreactivity in the Ammon's horn region 1 (CA1) and the dentate gyrus areas of the hippocampus. This reduction was concentration-dependent, with the maximum reduction observed in rats exposed to 750 ppm lead. Taken together, these findings suggest that exposure to lead causes spatial memory deficits in male rats and a significant reduction in cyclooxygenase-2 immunoreactivity in the CA1 and dentate gyrus areas.

Protective effects of chronic lithium treatment against spatial memory retention deficits induced by the protein kinase AII inhibitor H-89 in rats.

We have previously shown that infusion of the PKAII inhibitor H-89 in the CA1 area of the hippocampus impaired spatial memory retention. There is some evidence suggesting the neuroprotective effects of chronic lithium administration including its ability to attenuate a deleterious effect of chronic stress on spatial memory in rats. In the present study, we investigated whether chronic administration of lithium can improve memory as well as influence the inhibitory effect of H-89 on spatial memory retention. Male albino rats were treated systemically with lithium (600 mg/l) for 4 weeks and then trained for 4 days in the Morris water maze. Testing the animals 48 h later showed a significant reduction in escape latency (p < 0.05) and travel distance (p < 0.05) compared to the controls. In separate experiments, the rats were similarly treated with lithium for 4 weeks, followed by similar training for 4 days and then immediately infused bilaterally with vehicle or 5 micromol/l H-89 into the CA1 region of the hippocampus. Animals were then tested 48 h after H-89 infusion in order to assess their spatial memory retention. The lithium treatment caused a significant reduction in escape latency (p < 0.001) and travel distance (p < 0.001) compared to H-89-treated animals. The data suggest that lithium treatment for 4 weeks improved spatial memory retention and that lithium pretreatment prevented or reversed the H-89-induced spatial memory deficits.

Post-training intrahippocampal infusion of nicotine-bucladesine combination causes a synergistic enhancement effect on spatial memory retention in rats.

We previously had shown that bilateral intrahippocampal infusion of 1 microg nicotine (but not 0.5 microg dose) led to an improvement in spatial memory retention in the Morris water maze task in male rats. We also reported that a similar type of bilateral infusion of H89, a protein kinase AII (PKA II) inhibitor, caused a deficit in spatial memory retention. In the present study, we wished to test the hypothesis that intrahippocampal infusion of dibutyryl cyclic AMP (DB-cAMP also called bucladesine), a membrane permeable selective activator of PKA, into the CA1 region can cause an improvement in spatial memory in this maze task. Indeed, bilateral infusion of 10 and 100 microM bucladesine (but not 1 and 5 microM doses) led to a significant reduction in escape latency and travel distance (showing an improvement in spatial memory) compared to the control. Also, bilateral infusion of 0.5 microg nicotine or 1 microM bucladesine alone did not lead to an improvement in spatial memory. However, such bilateral infusion of bucladesine at 1 and 5 microM concentrations infused within minutes after 0.5 microg nicotine infusion improved spatial memory retention. Taken together, our data suggest that intrahippocampal bucladesine infusions improve spatial memory retention in male rats and that bucladesine can interact synergistically with nicotine to improve spatial memory.