New anti-inflammatory treatment strategy in Alzheimer's disease

Mefenamic Acid Loaded and TPGS Stabilized Mucoadhesive Nanoemulsion for the Treatment of Alzheimer's Disease: Development, Optimization, and Brain-Targeted Delivery via Olfactory Pathway

Alzheimer's disease (AD) is a very common disorder that affects the elderly. There are relatively few medications that can be used orally or as a suspension to treat AD. A mucoadhesive (o/w) nano emulsion of mefenamic acid was made by adding Carbopol 940P to the optimised drug nanoemulsion using distilled water as the aqueous phase (6%); Solutol HS: tween 20 (3.6%) as the surfactant and co-surfactant; and clove oil: TPGS (0.4%) as the oil phase and mefenamic acid as the drug (2.8 mg/ml). The mucoadhesive nanoemulsion (S40.5%w/v) had a particle size of 91.20 nm, polydispersity index of 0.270, and surface charge of - 12.4 mV. Significantly higher (p < 0.001) drug release (89.37%) was observed for mucoadhesive drug formulation in comparison to mucoadhesive drug suspension (25.64%) at 8 h. The ex vivo nasal permeation of 83.03% in simulated nasal fluid and 85.71% in artificial cerebrospinal fluid was observed. The percent inhibition and inhibitory concentration (IC50) of mucoadhesive drug nanoemulsion were found to be 91.57 ± 2.69 and 6.76 respectively. Higher cell viability on glioblastoma cells (85-80%) was researched for mucoadhesive nanoemulsion as compared to drug suspension (80-70%). Significantly higher (p < 0.001) drug absorption and Cmax (491.94 ± 24.13 ng/ml) of mucoadhesive drug nanoemulsion were observed than mucoadhesive drug suspension (107.46 ± 11.46 ng/ml) at 8 h. The stability studies confirmed that the formulation was stable at 40°C ± 2°C and 75 ± 5% RH. The authors concluded that the mucoadhesive mefenamic acid-loaded nanoemulsion may be an effective technique for treating Alzheimer's disease by intranasal route.

Sex Difference in Effects of Low-Dose Aspirin on Prevention of Dementia in Patients With Type 2 Diabetes: A Long-term Follow-up Study of a Randomized Clinical Trial

OBJECTIVE

To evaluate and compare the efficacy of long-term use of low-dose aspirin for the prevention of dementia in men and women.

RESEARCH DESIGN AND METHODS

This study is a follow-up cohort study of the Japanese Primary Prevention of Atherosclerosis With Aspirin for Diabetes (JPAD) trial, which was a randomized, open-label, standard care-controlled trial examining the effects of low-dose aspirin on cardiovascular events. We followed up 2,536 Japanese patients with type 2 diabetes (T2D) enrolled in the JPAD trial from 2002 to 2017. The primary outcome of this post hoc analysis was the incidence of dementia, which was defined by the prescription of antidementia drugs or admission due to dementia.

RESULTS

Among the originally enrolled patients, 2,121 (84%) retained their original allocation. During a median follow-up of 11.4 years, 128 patients developed dementia. The overall effect of low-dose aspirin on the prevention of dementia adjusted for age, sex, and other established risk factors was not significant (hazard ratio [HR] 0.82, 95% CI 0.58-1.16). However, a significant reduction was seen in the risk of dementia in women (HR 0.58, 95% CI 0.36-0.95), but not in men (HR 1.27, 95% CI 0.75-2.13) (P _interaction = 0.03).

CONCLUSIONS

Long-term use of low-dose aspirin may reduce the risk for dementia in women with T2D.

Examining barbiturate scaffold for the synthesis of new agents with biological interest

Aim: Barbiturates have a long history of being used as drugs presenting wide varieties of biological activities (antimicrobial, anti-urease and antioxidant). Reactive oxygen species are associated with inflammation implicated in cancer, atherosclerosis and autoimmune diseases. Multitarget agents represent a powerful approach to the therapy of complicated inflammatory diseases. Results: A novel series of barbiturates has been synthesized and evaluated in several in vitro assays. Compound 16b (lipoxygenases inhibitor, 55.0 μM) was found to be a cyclooxygenase-2 inhibitor (27.5 μM). Compound 8b was profiled as a drug-like candidate. Conclusion: The barbiturate core represents a new scaffold for lipoxygenases inhibition, and the undertaken derivatives show promise as multiple-target agents to combat inflammatory diseases.

P2Y1 and Cysteinyl Leukotriene Receptors Mediate Purine and Cysteinyl Leukotriene Co-Release in Primary Cultures of Rat Microglia

Inflammation is widely recognized as contributing to the pathology of acute and chronic neurodegenerative conditions. Microglial cells are pathologic sensors in the brain and activated microglia have been viewed as detrimental. Leukotriene, including cysteinyl leukotrienes (CysLTs) are suggested to be involved in brain inflammation and neurological diseases and ATP, by its receptors is a candidate for microglia activation. A23187 (10μM) stimulated microglia to co-release CysLTs and [3H]adenine based purines ([3H]ABPs), mainly ATP. The biosynthetic production of CysLTs was abolished by 10μM MK-886, an inhibitor of 5-lipoxygenase-activating protein activity. RT-PCR analysis showed that microglia expressed both CysLT1 / CysLT2 receptors, P2Y1 ATP-receptors and several members of the ATP binding cassette (ABC) transporters including MRP1, MRP4 and Pgp. The increase in [Ca2+]i elicited by LTD4 (0.1 μM) and 2MeSATP (100μM), agonists for CysLT- and P2Y1-receptors, was abolished by the respective antagonists, BAYu9773 (0.5 μM) and suramin (50 μM). The stimulation of both receptor subtypes, induced a concomitant increase in the release of both [3H]ABPs and CysLTs that was blocked by the antagonists and significantly reduced by a cocktail of ABC transporter inhibitors, BAPTA/AM (intracellular Ca2+ chelator) and staurosporine (0.1 μM, PKC blocker). P2Y antagonist was unable to antagonise the effects of LTD4 and BAYu9773 did not reduce the effects of 2MeSATP. These data suggest that: i) the efflux of purines and cysteinyl-leukotrienes is specifically and independently controlled by the two receptor types, ii) calcium, PKC and the ABC transporter system can reasonably be considered common mechanisms underlying the release of ABPs and CysLTs from microglia. The blockade of P2Y1 or CysLT1/CysLT2 receptors by specific antagonists that abolished the raise in [Ca2+]i and drastically reduced the concomitant efflux of both compounds, as well as the effects of BAPTA and staurosporine support this hypothesis. In conclusion, the data of the present study suggest a cross talk between the purine and leukotriene systems in a possible autocrine/paracrine control of the microglia-mediated initiation and progression of an inflammatory response.

Chemical Speciation of the System Cu(II)-Indomethacin in Ethanol and Water by UV-Vis Spectrophotometry

It has been proposed that the metal-drug complexes could be in fact the active agents displaying therapeutic effects of drugs. The characterization of the global formation equilibrium of complexes formed between metal ions and species with biological activity such as nonsteroidal anti-inflammatory drugs provides essential information to understand the mechanism of action of drugs. Since equilibrium constants determine the relative predominance of species, they provide crucial information to identify what complexes are more likely to be present in the system being responsible for the therapeutic effects of the drug. In this paper, the systems formed between copper and Indomethacin of different concentrations in ethanol or water were studied by UV-Vis spectrophotometry. The stoichiometry of the complexes Cu(II)–Indomethacin and their formation constants were investigated. Moreover, molecular structures of the Cu(II)–Indomethacin complexes were explored by means of the molecular modeling within the frame of the density functional theory.

A biological perspective of CSF lipids as surrogate markers for cognitive status in HIV

The development and application of biomarkers to neurodegenerative diseases has become increasingly important in clinical practice and therapeutic trials. While substantial progress has been made at the basic science level in understanding the pathophysiology of HIV-Associated Neurocognitive Disorders (HAND), there are significant limitations in our current ability to predict the onset or trajectory of disease, and to accurately determine the effects of therapeutic interventions. Thus, the development of objective biomarkers is critical to further our understanding and treatment of HAND. In recent years, biomarker discovery efforts have largely been driven forward through the implementation of multiple "omics" approaches that include (but are not restricted to): Lipidomics, proteomics, metabolomics, genomics, transcriptomics, and advances in brain imaging approaches such as functional connectomics. In this paper we summarize our progress to date on lipidomic approaches to biomarker discovery, discuss how these data have influenced basic research on the neuropathology of HAND, and implications for the development of therapeutics that target metabolic pathways involved in lipid handling.

Plants traditionally used in age-related brain disorders (dementia): an ethanopharmacological survey

CONTEXT

Epidemiological studies have shown that despite mortality due to communicable diseases, poverty and human conflicts, the incidence of dementia increases in the developing world in tandem with the ageing population. Although some FDA approved drugs are available for the treatment of dementia, the outcomes are often unsatisfactory. In traditional practices of medicine, numerous plants have been used to treat cognitive disorders, including neurodegenerative diseases such as Alzheimer's disease (AD) and other memory-related disorders. In western medicine most of the drugs used for the treatment of neurodegenerative disorders are derived from plant sources.

OBJECTIVE

This article reviews plants and their active constituents that have been used for their reputed cognitive-enhancing and antidementia effects.

METHODS

A literature survey in Science Direct, Pubmed, and Google Scholar was performed to gather information regarding drug discovery from plants sources for the treatment of congnitive disorders and dementia.

RESULTS

More than forty herbal remedies were identified with cholinesterase inhibitory, anti-inflammatory, or antioxidant activities. Bioactive compounds include alkaloids, flavonoids, steroids, saponins, terpenoids, and essential oils. About eleven herbal plants with multipotent activity against AD are discussed.

CONCLUSION

Literature surveys show that most of the research has been conducted on herbal remedies effect on cholinesterase inhibitory and antioxidant activities. Studies regarding the effect of herbal drugs on β-secretase inhibitory activity and antiaggregation property are lacking. This review provides leads for identifying potential new drugs from plant sources for the treatment of neurodegenerative disorders.

Differential contribution of lipoxygenase isozymes to nigrostriatal vulnerability

The 5- and 12/15-lipoxygenase (LOX) isozymes have been implicated to contribute to disease development in CNS disorders such as Alzheimer's disease. These LOX isozymes are distinct in function, with differential effects on neuroinflammation, and the impact of the distinct isozymes in the pathogenesis of Parkinson's disease has not as yet been evaluated. To determine whether the isozymes contribute differently to nigrostriatal vulnerability, the effects of 5- and 12/15-LOX deficiency on dopaminergic tone under naïve and toxicant-challenged conditions were tested. In naïve mice deficient in 5-LOX expression, a modest but significant reduction (18.0% reduction vs. wildtype (WT)) in striatal dopamine (DA) was detected (n=6-8 per genotype). A concomitant decline in striatal tyrosine hydroxylase (TH) enzyme was also revealed in null 5-LOX vs. WT mice (26.2%); however, no changes in levels of DA or TH immunoreactivity were observed in null 12/15-LOX vs. WT mice. When challenged with the selective dopaminergic toxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), WT mice showed a marked reduction in DA (31.9%) and robust astrocytic and microglial activation as compared to saline-treated animals. In contrast, null 5-LOX littermates demonstrated no significant striatal DA depletion or astrogliosis (as noted by Western blot analyses for glial acidic fibrillary protein (GFAP) immunoreactivity). In naïve null 12/15-LOX mice, no significant change in striatal DA values was observed compared to WT, and following MPTP treatment, the transgenics revealed striatal DA reduction similar to the challenged WT mice. Taken together, these data provide the first evidence that: (i) LOX isozymes are involved in the maintenance of normal dopaminergic function in the striatum and (ii) the 5- and 12/15-LOX isozymes contribute differentially to striatal vulnerability in response to neurotoxicant challenge.

Cilostazol prevents amyloid β peptide(25-35)-induced memory impairment and oxidative stress in mice

BACKGROUND AND PURPOSE

Cilostazol may be effective in dementia associated with a cerebral ischaemia. In this study, we examined whether it exerts beneficial effects on learning and/or memory impairment induced by Aβ(25-35) in mice, and compared its effects with those of aspirin.

EXPERIMENTAL APPROACH

Aβ(25-35) (9 nmol) was administered to mice i.c.v. Learning and memory behaviour were evaluated by measuring spontaneous alternation in a Y-maze and a step-down type passive avoidance test, on the 5th and 8th days after injection respectively. Levels of lipid peroxidation (malondialdehyde) and cytokines in the frontal cortex and hippocampus were measured 2, 3, 5 and 7 days after the Aβ(25-35) injection. The effects of repeated administration of cilostazol and aspirin (both at 30 and 100 mg·kg(-1), p.o.) on any changes induced by Aβ(25-35) were evaluated.

KEY RESULTS

Repeated administration of cilostazol significantly attenuated the impairment of spontaneous alternation and the shortened step-down latency induced by Aβ(25-35) . Aspirin did not show any beneficial effect. A significant increase in the levels of malondialdehyde (MDA) and IL-1β (only measured in hippocampus) was observed 2, 3 and 5 days after the Aβ(25-35) injection in the frontal cortex and hippocampus. Repeated administration of cilostazol (100 mg·kg(-1)) completely prevented the increase in MDA levels but failed to antagonize the increase in the expression of IL-1β induced by Aβ(25-35).

CONCLUSIONS AND IMPLICATIONS

These results suggest that the protective effect of cilostazol on Aβ(25-35)-induced memory impairment may be related to oxidative stress in the frontal cortex and the hippocampus.

Inflammation in neurodegenerative diseases

Neurodegeneration, the slow and progressive dysfunction and loss of neurons and axons in the central nervous system, is the primary pathological feature of acute and chronic neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease, neurotropic viral infections, stroke, paraneoplastic disorders, traumatic brain injury and multiple sclerosis. Despite different triggering events, a common feature is chronic immune activation, in particular of microglia, the resident macrophages of the central nervous system. Apart from the pathogenic role of immune responses, emerging evidence indicates that immune responses are also critical for neuroregeneration. Here, we review the impact of innate and adaptive immune responses on the central nervous system in autoimmune, viral and other neurodegenerative disorders, and discuss their contribution to either damage or repair. We also discuss potential therapies aimed at the immune responses within the central nervous system. A better understanding of the interaction between the immune and nervous systems will be crucial to either target pathogenic responses, or augment the beneficial effects of immune responses as a strategy to intervene in chronic neurodegenerative diseases.

Potential Anti-Dementia Agents in Traditional Chinese Medicine

Dementia is becoming one of the biggest threats to human health. However, there is no efficient therapeutic approach so far. Thus, traditional medicines, which have accumulated certain experience in the treatment of dementia, are attracting more and more attention. Indeed, many anti-dementia drugs or drug candidates have been derived from these medicines. In this article, the profile of anti-dementia agents contained in traditional Chinese medicine (TCM) is described. It is indicated that TCM is not only a rich source of acetylcholinesterase inhibitors, but also of great potential to derive other kinds of anti-dementia agents which are either directly associated with ameliorating dementia or have complementary effects. These agents have apparent implications for anti-dementia drug discovery, especially for finding multicomponent anti-dementia drugs.

Mammalian nicotinic acetylcholine receptors: from structure to function

The classical studies of nicotine by Langley at the turn of the 20th century introduced the concept of a "receptive substance," from which the idea of a "receptor" came to light. Subsequent studies aided by the Torpedo electric organ, a rich source of muscle-type nicotinic receptors (nAChRs), and the discovery of alpha-bungarotoxin, a snake toxin that binds pseudo-irreversibly to the muscle nAChR, resulted in the muscle nAChR being the best characterized ligand-gated ion channel hitherto. With the advancement of functional and genetic studies in the late 1980s, the existence of nAChRs in the mammalian brain was confirmed and the realization that the numerous nAChR subtypes contribute to the psychoactive properties of nicotine and other drugs of abuse and to the neuropathology of various diseases, including Alzheimer's, Parkinson's, and schizophrenia, has since emerged. This review provides a comprehensive overview of these findings and the more recent revelations of the impact that the rich diversity in function and expression of this receptor family has on neuronal and nonneuronal cells throughout the body. Despite these numerous developments, our understanding of the contributions of specific neuronal nAChR subtypes to the many facets of physiology throughout the body remains in its infancy.

Increased 5-lipoxygenase immunoreactivity in the hippocampus of patients with Alzheimer's disease

The proinflammatory enzyme 5-lipoxygenase (5-LOX) is upregulated in Alzheimer's disease (AD), but its localization and association with the hallmark lesions of the disease, beta-amyloid (Abeta) plaques and neurofibrillary tangles (NFTs), is unknown. This study examined the distribution and cellular localization of 5-LOX in the medial temporal lobe from AD and control subjects. The spatial relationship between 5-LOX immunoreactive structures and AD lesions was also examined. We report that, in AD subjects, 5-LOX immunoreactivity is elevated relative to controls, and its localization is dependent on the antibody-targeted portion of the 5-LOX amino acid sequence. Carboxy terminus-directed antibodies detected 5-LOX in glial cells and neurons, but less frequently in neurons with dystrophic (NFT) morphology. In contrast, immunoreactivity observed using 5-LOX amino terminus-directed antibodies was virtually absent in neurons and abundant in NFTs, neuritic plaques, and glia. Double-labeling studies showed a close association of 5-LOX-immunoreactive processes and glial cells with Abeta immunoreactive plaques and vasculature and also detected 5-LOX in tau immunoreactive and amyloid containing NFTs. Different immunolabeling patterns with antibodies against carboxy vs amino terminus of 5-LOX may be caused by post-translational modifications of 5-LOX protein in Abeta plaques and NFTs. The relationship between elevated intracellular 5-LOX and hallmark AD pathological lesions provides further evidence that neuroinflammatory pathways contribute to the pathogenesis of AD.

Effects of zileuton and montelukast in mouse experimental spinal cord injury

BACKGROUND AND PURPOSE

5-lipoxygenase (5-LO) is the key enzyme in leukotriene (LT) biosynthesis from arachidonic acid (AA). Here, we examined the role of the 5-LO-product, cysteinyl-LT (Cys-LT), with a 5-LO inhibitor (zileuton) and a Cys-LT, receptor antagonist (montelukast), in the inflammatory response and tissue injury associated with spinal cord injury (SCI).

EXPERIMENTAL APPROACH

SCI was induced in mice by the application of vascular clips to the dura via a two-level T6 to T7 laminectomy for 1 min. Cord inflammation was assessed histologically and by measuring inflammatory mediators (ELISA) and apoptosis by annexin V, TUNEL, Fas ligand staining and Bax and Bcl-2 expression (immunohistochemistry and western blots). Motor function in hindlimbs was assessed by a locomotor rating scale, for 10 days after cord injury.

KEY RESULTS

SCI in mice resulted in tissue damage, oedema, neutrophil infiltration, apoptosis, tumour necrosis-alpha (TNF-alpha) and cyclooxygenase-2 (COX-2) expression, prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) production, and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in injured tissue. Treatment of the mice with zileuton or montelukast reduced the spinal cord inflammation and tissue injury, neutrophil infiltration, TNF-alpha, COX-2 and pERK1/2 expression, PGE(2) and LTB(4) production, and apoptosis. In separate experiments, zileuton or montelukast significantly improved the recovery of limb function over 10 days.

CONCLUSIONS AND IMPLICATIONS

Zileuton and montelukast produced a substantial reduction of inflammatory events associated with experimental SCI. Our data underline the important role of 5-LO and Cys-LT in neurotrauma.

Effect of acetaminophen, a cyclooxygenase inhibitor, on Morris water maze task performance in mice

Although the mechanism of action of acetaminophen (AAP) is not fully understood, some studies suggest that AAP and phenacetin (PHE) are selective cyclooxygenase (COX)-3 inhibitors. To examine the participation of COX-3 in memory formation, water maze performance was studied in mice treated with AAP, PHE or other COX inhibitors. Mice received intraperitoneal injections of drugs immediately after each training session. Administration of high-dose AAP [302.3 mg/kg (IC50 for COX-2)] or PHE [179.2 mg/kg (IC50 for COX-2)] and of non-specific (indomethacin: 20 mg/kg) or specific COX-2 (NS-398: 10 mg/kg) inhibitor impaired the performance in hidden platform (HP) not visible platform (VP) tasks, whereas low-dose (15.1 mg/kg) AAP facilitated performance in HP and VP tasks. The facilitation of performance by low-dose AAP was reversed by co-administration with a 5-HT(1/2) receptor antagonist (methysergide: 0.47 mg/kg). The middle-dose [69.5 mg/kg (IC50 for COX-3)] of AAP, the PHE [17.9 mg/kg (IC50 for COX-3)] and a specific COX-1 inhibitor (piroxicam: 10-20 mg/kg) did not influence performance in either task. These results suggest that the memory impairment by high-dose AAP and PHE and facilitation of performance by low-dose AAP could involve endogenous COX-2 and serotonergic neuronal activity, but not COX-3, respectively.

Inhibitors of brain phospholipase A2 activity: their neuropharmacological effects and therapeutic importance for the treatment of neurologic disorders

The phospholipase A(2) family includes secretory phospholipase A(2), cytosolic phospholipase A(2), plasmalogen-selective phospholipase A(2), and calcium-independent phospholipase A(2). It is generally thought that the release of arachidonic acid by cytosolic phospholipase A(2) is the rate-limiting step in the generation of eicosanoids and platelet activating factor. These lipid mediators play critical roles in the initiation and modulation of inflammation and oxidative stress. Neurological disorders, such as ischemia, spinal cord injury, Alzheimer's disease, multiple sclerosis, prion diseases, and epilepsy are characterized by inflammatory reactions, oxidative stress, altered phospholipid metabolism, accumulation of lipid peroxides, and increased phospholipase A(2) activity. Increased activities of phospholipases A(2) and generation of lipid mediators may be involved in oxidative stress and neuroinflammation associated with the above neurological disorders. Several phospholipase A(2) inhibitors have been recently discovered and used for the treatment of ischemia and other neurological diseases in cell culture and animal models. At this time very little is known about in vivo neurochemical effects, mechanism of action, or toxicity of phospholipase A(2) inhibitors in human or animal models of neurological disorders. In kainic acid-mediated neurotoxicity, the activities of phospholipase A(2) isoforms and their immunoreactivities are markedly increased and phospholipase A(2) inhibitors, quinacrine and chloroquine, arachidonyl trifluoromethyl ketone, bromoenol lactone, cytidine 5-diphosphoamines, and vitamin E, not only inhibit phospholipase A(2) activity and immunoreactivity but also prevent neurodegeneration, suggesting that phospholipase A(2) is involved in the neurodegenerative process. This also suggests that phospholipase A(2) inhibitors can be used as neuroprotectants and anti-inflammatory agents against neurodegenerative processes in neurodegenerative diseases.

Alzheimer's disease and Helicobacter pylori infection: Defective immune regulation and apoptosis as proposed common links

Although degenerative diseases of the central nervous system, including Alzheimer's disease (AD), have an increasingly high impact on aged population their association with Helicobacter pylori (H. pylori) infection has not as yet been thoroughly researched. Current H. pylori infection appears to induce irregular humoral and cellular immune responses that, owing to the sharing of homologous epitopes (molecular mimicry), cross-react with components of nerves, thereby contributing and possibly perpetuating the apoptotic neural tissue damage observed in neurodegenerative diseases including AD. An association between AD and H. pylori infection has been recently addressed by two studies. A higher seropositivity for anti-H. pylori immunoglobulin G antibodies in 30 patients with AD than in 30 age-matched controls was reported in one study; this serological test, however, has limitations because it does not discriminate between current and old infections. In the other study, by introducing the histological method (the actual gold standard) for diagnosis of H. pylori infection, we reported a higher prevalence of H. pylori infection in 50 AD patients than in 30 anemic controls. This pathogen may influence the pathophysiology of AD by promoting platelet and platelet-leukocyte aggregation; releasing various pro-inflammatory and vasoactive substances; developing cross-mimicry with host antigens; producing reactive oxygen metabolites and circulating lipid peroxides; influencing the apoptotic process; and increasing, through induction of atrophic gastritis, homocysteine, which contributes to vascular disorders implicated in endothelial damage and neurodegeneration.

The 5-lipoxygenase enzymatic pathway in the mouse brain: young versus old

The 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism is an important source of inflammatory mediators, and is also present in the central nervous system. In this study, we assayed the expression levels and activity of 5-LO in different brain regions of young versus old C57Bl/6 mice. 5-LO mRNA was expressed in all the brain regions considered, i.e. cortex, hippocampus, and cerebellum. The highest expression level was observed in cerebellum compared with cortex and hippocampus, although it was not affected by aging. By contrast, 5-LO mRNA and protein levels were significantly increased in the hippocampus of old (25 months) versus young (3 months) mice. Finally, levels of the leukotriene B4, a metabolic product of 5-LO, were significantly increased in the hippocampus of old mice, but no difference was observed in cortex and cerebellum. These results demonstrate that the 5-LO enzymatic pathway is widely expressed in the mouse CNS, where significant changes are region-specific and age-dependent. This observation supports the hypothesis that 5-LO may be involved in diseases of the brain associated with aging.

Ulva conglobata, a marine algae, has neuroprotective and anti-inflammatory effects in murine hippocampal and microglial cells

It has been reported that inflammatory processes are associated with the pathophysiology of Alzheimer's disease (AD), and the treatment of AD using anti-inflammatory agents slows the progress of AD. Marine algae have been utilized in food products as well as in medicine products for a variety of purposes. In this study, we investigated the neuroprotective effects of methanol extracts of Ulva conglobata (U. conglobata), a marine algae, on glutamate-induced neurotoxicity in the murine hippocampal HT22 cell line and the anti-inflammatory effects on interferon gamma (IFN-gamma)-induced microglial activation in BV2 cells. U. conglobata methanol extracts significantly attenuated the neurotoxicity induced by glutamate in HT22 cells and inhibited nitric oxide production induced by IFN-gamma in BV2 cells. U. conglobata methanol extract treatments were also examined and it was found that they almost completely suppressed the expression of the proinflammatory enzyme cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). These results suggest that U. conglobata possesses therapeutic potential for combating neurodegenerative diseases associated with neuroinflammation.

Synthesis and pharmacochemical study of novel polyfunctional molecules combining anti-inflammatory, antioxidant, and hypocholesterolemic properties

We have designed and synthesized a series of novel molecules having a residue of a classical NSAID and an antioxidant moiety, both attached through amide bonds to a known nootropic structure, an L-proline, trans-4-hydroxy-L-proline or DL-pipecolinic acid residue. The compounds were found to retain anti-inflammatory and antioxidant activities, to acquire hypocholesterolemic action, and to possess a greatly reduced gastrointestinal toxicity. The novel molecules could find useful applications, among others, in slowing the progression or delaying the onset of neurodegenerative diseases.

Mefenamic Acid Shows Neuroprotective Effects and Improves Cognitive Impairment in in Vitro and in Vivo Alzheimer's Disease Models

Nonsteroidal anti-inflammatory drugs (NSAIDs) exert anti-inflammatory, analgesic, and antipyretic activities and suppress prostaglandin synthesis by inhibiting cyclooxygenase, an enzyme that catalyzes the formation of prostaglandin precursors from arachidonic acid. Epidemiological observations indicate that the long-term treatment of patients suffering from rheumatoid arthritis with NSAIDs results in reduced risk and delayed onset of Alzheimer's disease. In this study, we investigated the therapeutic potential for Alzheimer's disease of mefenamic acid, a commonly used NSAID that is a cyclooxygenase-1 and 2 inhibitor with only moderate anti-inflammatory properties. We found that mefenamic acid attenuates the neurotoxicities induced by amyloid beta peptide (Abeta)(1-42) treatment and the expression of a Swedish double mutation (KM595/596NL) of amyloid precursor protein (Swe-APP) or the C-terminal fragments of APP (APP-CTs) in neuronal cells. We also show that mefenamic acid decreases the production of the free radical nitric oxide and reduces cytochrome c release from mitochondria induced by Abeta(1-42), Swe-APP, or APP-CTs in neuronal cells. In addition, mefenamic acid up-regulates expression of the antiapoptotic protein Bcl-X(L). Moreover, our study demonstrates for the first time that mefenamic acid improves learning and memory impairment in an Abeta(1-42)-infused Alzheimer's disease rat model. Taking these in vitro and in vivo results together, our study suggests that mefenamic acid could be used as a therapeutic agent in Alzheimer's disease.

5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR) attenuates the expression of LPS- and Abeta peptide-induced inflammatory mediators in astroglia

BACKGROUND

Alzheimer's disease (AD) pathology shows characteristic 'plaques' rich in amyloid beta (Abeta) peptide deposits. Inflammatory process-related proteins such as pro-inflammatory cytokines have been detected in AD brain suggesting that an inflammatory immune reaction also plays a role in the pathogenesis of AD. Glial cells in culture respond to LPS and Abeta stimuli by upregulating the expression of cytokines TNF-alpha, IL-1beta, and IL-6, and also the expression of proinflammatory genes iNOS and COX-2. We have earlier reported that LPS/Abeta stimulation-induced ceramide and ROS generation leads to iNOS expression and nitric oxide production in glial cells. The present study was undertaken to investigate the neuroprotective function of AICAR (a potent activator of AMP-activated protein kinase) in blocking the pro-oxidant/proinflammatory responses induced in primary glial cultures treated with LPS and Abeta peptide.

METHODS

To test the anti-inflammatory/anti-oxidant functions of AICAR, we tested its inhibitory potential in blocking the expression of pro-inflammatory cytokines and iNOS, expression of COX-2, generation of ROS, and associated signaling following treatment of glial cells with LPS and Abeta peptide. We also investigated the neuroprotective effects of AICAR against the effects of cytokines and inflammatory mediators (released by the glia), in blocking neurite outgrowth inhibition, and in nerve growth factor-(NGF) induced neurite extension by PC-12 cells.

RESULTS

AICAR blocked LPS/Abeta-induced inflammatory processes by blocking the expression of proinflammatory cytokine, iNOS, COX-2 and MnSOD genes, and by inhibition of ROS generation and depletion of glutathione in astroglial cells. AICAR also inhibited down-stream signaling leading to the regulation of transcriptional factors such as NFkappaB and C/EBP which are critical for the expression of iNOS, COX-2, MnSOD and cytokines (TNF-alpha/IL-1beta and IL-6). AICAR promoted NGF-induced neurite growth and reduced neurite outgrowth inhibition in PC-12 cells treated with astroglial conditioned medium.

CONCLUSION

The observed anti-inflammatory/anti-oxidant and neuroprotective functions of AICAR suggest it as a viable candidate for use in treatment of Alzheimer's disease.

Fatty acid oxidation in the pathogenesis of Alzheimer's disease

Alzheimer's disease (AD) is the most common dementing illness of the elderly and is a mounting public health problem. Pharmacoepidemiological data, analytical data from human tissue and body fluids, and mechanistic data mostly from murine models all have implicated oxidation products of two fatty acids, arachidonic acid (AA) and docosahexaenoic acid (DHA), in the pathogenesis of neurodegeneration. Here we review the biochemistry of AA and DHA oxidation, both enzyme-catalyzed and free radical mediated, and summarize those studies that have investigated these oxidation products as effectors of neurodegeneration and biomarkers of AD. Given the evolving appreciation for toxicity associated with current pharmaceuticals used to block AA and DHA oxidation, we close by speculating on likely areas of future research directed at suppressing this facet of neurodegeneration. If successful, these interventions are unlikely to cure AD, but may check its explosive growth and hopefully reduce its incidence and prevalence in the elderly.

Age-related loss of neuronal nicotinic receptor expression in the aging mouse hippocampus corresponds with cyclooxygenase-2 and PPAR? expression and is altered by long-term NS398 administration

Age-related changes in the mammalian dorsal hippocampus are associated with diminished expression of neuronal nicotinic acetylcholine receptors (nAChR), which is particularly severe in pathologies such as those associated with dementias, including Alzheimer's disease. Because the mouse is a useful model for age-related decline in nAChR expression in the basal forebrain and limbic system, we used immunohistochemistry to examine the influence of long-term (12-month) oral administration of nicotine and/or the cyclooxygenase-2 (COX-2) preferring non-steroidal anti-inflammatory drug (NSAID) NS398 on nAChR alpha4, alpha5, alpha7, and beta4 expression in the C57BL/6 mouse. Inhibitory neurons of the dorsal hippocampus that express nAChRs also constitutively express COX-2 and the peroxisome proliferator-antagonist receptor subtype gamma-2 (PPAR gamma2) which is also a target of NS398. Administration of NS398 correlated with retention of nAChR alpha4 and to a lesser extent nAChR beta4, but not nAChR alpha5 or alpha7, but nicotine exhibited no similar effect. Nicotine and NS398 co-administration abolished the NS398-related effect on nAChR alpha4 retention. These results provide evidence that the interaction during aging between oral administration of nicotine and NSAIDs are not straightforward and could even be antagonistic when combined.

Potential prodrugs of non-steroidal anti-inflammatory agents for targeted drug delivery to the CNS

Recently non-steroidal anti-inflammatory drugs (NSAIDs) have been proposed to prevent or to cure Alzheimer's disease. In this respect, we synthesized new potential prodrugs of several NSAIDs in order to increase their access to the brain. The carboxylic group of NSAIDs was attached to the 1,4-dihydro-1-methylpyridine-3-carboxylate moiety, which acts as a carrier, via an amino alcohol bridge, according to the chemical delivery approach developed by Bodor. The lipophilicity of potential prodrugs was evaluated both via traditional experimental parameters, such as partition coefficient and chromatographic R(m) value, and by predictive computational methods. From experimental parameters, all prodrugs were more lipophilic when compared to their corresponding parent compounds and consequently a better blood brain barrier (BBB) penetration is hypothesised. Prodrug lipophilicity was correlated with a calculated log P value according to Kowwin's method. The correlation between experimental Rm0 and calculated log P, determined by PLS analysis, was good for all compounds with the exception of compound 7i. In addition the BBB permeation profile of our synthesized compounds was predicted using the BBB VolSurf model and seven of the synthesized prodrugs resulted in good candidates for BBB penetration.

Salvia for dementia therapy: review of pharmacological activity and pilot tolerability clinical trial

S. lavandulaefolia Vahl. (Spanish sage) extracts and constituents have demonstrated anticholinesterase, antioxidant, anti-inflammatory, oestrogenic and CNS depressant (sedative) effects all of which are currently relevant to the treatment of Alzheimer's disease (AD). The essential oil inhibits the enzyme acetylcholinesterase (AChE) from human brain tissue and bovine erythrocyte and individual monoterpenoid constituents inhibit AChE with varying degrees of potency. In vivo AChE inhibition of select brain (striatal and hippocampal over cortical) AChE was obtained following oral administration of the essential oil to rats. In a study in healthy volunteers essential oil administration produced significant effects on cognition. In a pilot open-label study involving oral administration of the essential oil to patients with AD, a significant increase in diastolic and systolic blood pressure was observed in two patients, however this may have been due primarily to preexisting hypertension and there were no abnormalities in other vital signs or blood samples during the trial period. Although an open label trial is not free from practice effects or rater-caregiver expectations, statistically significant differences between baseline and 6 weeks treatment were a reduction in neuropsychiatric symptoms and an improvement in attention.

Modulatory role of cyclooxygenase inhibitors in aging- and scopolamine or lipopolysaccharide-induced cognitive dysfunction in mice

Inflammation processes may play a critical role in the pathogenesis of the degenerative changes and cognitive impairments associated with Alzheimer's disease (AD). Non-steroidal anti-inflammatory drugs are reported to be effective in reducing the risk of developing AD or cognitive impairments. Present experiments were performed to study the possible effect of various NSAIDs on cognitive performance of young, aged and scopolamine or lipopolysaccharide (LPS) treated mice (an animal model of AD) using one trial step through type of passive avoidance and in elevated plus maze task. Chronic administration of NSAIDs at the ED(50) doses (nimesulide, rofecoxib and naproxen for 15 days) significantly reversed the age or scopolamine-induced retention deficits in both test paradigms. However, in both the memory paradigms chronic administration of NSAIDs failed to modulate the retention performance of young mice. Acute administration of LPS (50 mcg/mouse, i.p.) significantly exhibited retention deficits after 24 h and seventh day of its administration in both test paradigms. Chronic administration (7 days) of rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor (1.92 mg/kg, p.o.) significantly reversed the LPS-induced retention deficits in both tests. The results of this study showed chronic treatment of NSAIDs reverses the cognitive deficits in age and scopolamine or LPS treated mice. These findings establish a link between the central nervous system expression of various pro-inflammatory cytokines and learning impairment in mice.

Neutrophils CD11b and fibroblasts PGE(2) are elevated in Alzheimer's disease

To evaluate whether inflammation-like mechanisms present in the brain of Alzheimer's disease (AD) patients are reflected in the periphery, the expression of CD11b in peripheral blood neutrophils and the expression and activity of inflammatory markers in cultured skin fibroblasts were examined. We found significantly higher levels of CD11b in neutrophils from sporadic AD patients than in controls and this elevation was positively correlated with disease severity and progression rate of mental decline. Cultured skin fibroblasts from familial (FAD) and sporadic AD patients and from controls were immunopositive for both isoforms of cyclooxygenase with no differences between groups. In unstimulated culture, the production of prostaglandin-E2 in the medium was significantly higher in fibroblasts from sporadic AD and FAD patients than in controls, and this elevation was reverted by the addition of 25 microM of ibuprofen. Our findings provide further evidence of the presence of inflammatory and immuno-related markers in the periphery of AD patients and support those studies indicating the beneficial effects of anti-inflammatory therapy in AD.

The diet-induced proinflammatory state: a cause of chronic pain and other degenerative diseases?

BACKGROUND

It is the rare physician who includes diet therapy and nutritional supplements in patient care. Perhaps this is because chiropractic and medical schools devote very few classroom hours to nutrition. It is also possible that physicians are under the misconception that a detailed biochemical understanding of each individual disease is required before nutritional interventions can be used.

OBJECTIVE

The purpose of this article is two-fold: (1) to demonstrate that chronic pain and other degenerative conditions encountered in clinical practice have similar biochemical etiologies, such as a diet-induced proinflammatory state, and (2) to outline a basic nutritional program that can be used by all practitioners.

DATA SOURCES

The data were accumulated over a period of years by reviewing contemporary articles and books and subsequently by retrieving relevant articles. Articles were also selected through MEDLINE and manual library searches.

RESULTS

The typical American diet is deficient in fruits and vegetables and contains excessive amounts of meat, refined grain products, and dessert foods. Such a diet can have numerous adverse biochemical effects, all of which create a proinflammatory state and predispose the body to degenerative diseases. It appears that an inadequate intake of fruits and vegetables can result in a suboptimal intake of antioxidants and phytochemicals and an imbalanced intake of essential fatty acids. Through different mechanisms, each nutritional alteration can promote inflammation and disease.

CONCLUSION

We can no longer view different diseases as distinct biochemical entities. Nearly all degenerative diseases have the same underlying biochemical etiology, that is, a diet-induced proinflammatory state. Although specific diseases may require specific treatments, such as adjustments for hypomobile joints, beta-blockers for hypertension, and chemotherapy for cancer, the treatment program must also include nutritional protocols to reduce the proinflammatory state.

[Glial activation and brain aging]

While basal forebrain cholinergic neurons degenerate in aging and Alzheimer's disease, the cholinergic groups of the upper brainstem are preserved. Since the brainstem reticular-like cholinergic neurons differ from the rostral cholinergic phenotype by their high expression of nitric oxide synthase (NOS) mRNA, we hypothesized that they contain biochemical mechanisms to protect themselves against self-induced damage by nitric oxide (NO). Our initial question was a source of the NO during the aging process. We found a significant correlation between cognitive function and markers for glial activation and oxidative stress using aged rats. This result indicates that oxidative stress accompanied by glial activation may be occurred in the cognitively impaired animals. We also found mitochondrial DNA (mDNA) was significantly damaged in these animals, while accumulation of oxidative damage was not evident in other molecules. Therefore, oxidative damage to the mDNA by glial activation may occur in the cells having poor protection against oxidative stress during aging. Then the dysfunction of mitochondria, induced by the mDNA damage, may induce cell death as well as produce another oxidative stress to cause neuronal damage. The damaged neurons induce further glial activation and such self-accelerated immune-like response results in progressive neurodegeneration.

In-vitro activity of S. lavandulaefolia (Spanish sage) relevant to treatment of Alzheimer's disease

Salvia lavandulaefolia Vahl. (Spanish sage) essential oil and individual monoterpenoid constituents have been shown to inhibit the enzyme acetylcholinesterase in-vitro and in-vivo. This activity is relevant to the treatment of Alzheimer's disease, since anticholinesterase drugs are currently the only drugs available to treat Alzheimer's disease. Other activities relevant to Alzheimer's disease include antioxidant, anti-inflammatory and estrogenic effects. Results of in-vitro tests for these activities are reported here for S. lavandulaefolia extracts, the essential oil and its major constituents. Antioxidant activity (inhibition of bovine brain liposome peroxidation) was found in the EtOH extract of the dried herb (5 mg mL(-1)) and the monoterpenoids (0.1 M) alpha- and beta-pinene and 1,8-cineole. Thujone and geraniol had lower antioxidant effects, while camphor had no antioxidant effects. Possible anti-inflammatory activity (eicosanoid inhibition in rat leucocytes) was found in the EtOH extract (50 microg mL(-1)) and was shown by the monoterpenoids alpha-pinene and geraniol (0.2 mM), but not 1,8-cineole, thujone or camphor. Possible estrogenic activity (via induction of beta-galactosidase activity in yeast cells) was found in the essential oil (0.01 mg mL(-1)) and the monoterpenoid geraniol (0.1-2 mM). 1,8-Cineole, alpha- and beta-pinene and thujone did not exhibit estrogenic activity in this analysis. These results demonstrate that S. lavandulaefolia, its essential oil and some chemical constituents have properties relevant to the treatment of Alzheimer's disease and provide further data supporting the value of carrying out clinical studies in patients with Alzheimer's disease using this plant species.

Neurogenesis and neuroprotection in the adult brain. A putative role for 5-lipoxygenase?

5-Lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) are two enzymes that are critical for the synthesis of eicosanoids, the inflammatory metabolites of arachidonic acid. Both 5-LOX and COX-2 are expressed in the brain, including in CNS neurons. The physiologic role of these proteins in neuronal functioning is not clear. In non-neuronal tissues these two enzymes often assume similar roles: in addition to their function in inflammation, 5-LOX and COX-2 appear to be associated with cell proliferation, that is, with tumor growth. High 5-LOX expression has been noticed in the proliferating brain or pancreatic tumor cells; reduction in tumor cell proliferation and/or destruction of tumor cells was achieved with 5-LOX inhibitors. Proliferation of immature neurons/neuroblasts is an important component of mitotic neurogenesis. We investigated the role of 5-LOX in proliferation using cultures of human neuronal precursor cells, NT2. We found that these cells express 5-LOX mRNA and we used 3H-thymidine incorporation as a measure of cell proliferation; this was reduced by treating the cultures with 5-LOX inhibitor AA-861. We propose that the 5-LOX pathway plays a crucial role in mitotic neurogenesis. Additional studies should explore whether 5-LOX may participate in neurogenesis related pathologies and whether it should be considered a target for procedures aimed at altering neurogenesis for therapeutic purposes.

Neurotoxicity as a mechanism for neurodegenerative disorders: basic and clinical aspects

This three day meeting focused on chronic neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), and amylotrophic lateral sclerosis (ALS). It attracted 69 participants from 10 countries with dominance of Chile and USA. Neurodegeneration and its prevention increasingly gain in importance as the number of people affected increases year-by-year. The meeting addressed various basic aspects having pragmatic implications such as: oxidative stress, inflammatory reaction, glial activation, role of glutamatergic system and apoptosis using a plethora of in vitro and in vivo methods.