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Alzheimer's Disease



Protective effect of L-deprenyl against apoptosis induced by okadaic acid in cultured neuronal cells.

Suuronen T, Kolehmainen P, Salminen A Department of Neuroscience and Neurology, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland.

Biochem Pharmacol 2000 Jun 15;59(12):1589-95

L-Deprenyl, an irreversible MAO-B (monoamine oxidase B, EC inhibitor, is used for the treatment of Parkinson's disease and to delay the progression of Alzheimer's disease. L-Deprenyl also exhibits protective effects against neuronal apoptosis which are independent of its ability to inhibit MAO-B. The purpose of this study was to compare the antiapoptotic efficacy of L-deprenyl against different types of apoptotic inducers in three neuronal cell culture models. The level of apoptosis was quantified by measuring the activation of caspase-3 enzyme, which is the main apoptotic executioner in neuronal cells. MTT [3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] and LDH (lactate dehydrogenase, EC 1. 1.1.27) assays were used to demonstrate the cytotoxic response of apoptotic treatments. Our results showed that okadaic acid, an inhibitor of protein phosphatase 1 and 2A, induced a prominent increase in caspase-3 activity both in cultured hippocampal and cerebellar granule neurons as well as in Neuro-2a neuroblastoma cells. Interestingly, L-deprenyl offered a significant protection against the apoptotic response induced by okadaic acid in all three neuronal models. The best protection appeared at the concentration level of 10(-9) M. L-Deprenyl also provided a protection against apoptosis after AraC (cytosine beta-D-arabinoside) treatment in hippocampal neurons and Neuro-2a cells and after etoposide treatment in Neuro-2a cells. However, L-deprenyl did not offer any protection against apoptosis caused by serum withdrawal or potassium deprivation. Okadaic acid treatment in vivo is known to induce an Alzheimer's type of hyperphosphorylation of tau protein, formation of beta-amyloid plaques, and a severe memory impairment. Our results show that the okadaic acid model provides a promising tool to study the molecular basis of Alzheimer's disease and to screen the neuroprotective capacity of L-deprenyl derivatives.

Vitamin E for Alzheimer's disease.

Tabet N, Birks J, Grimley Evans J. Old Age Psychiatry, The Maudsley Hospital, Denmark Hill, London, UK, SE5 8AZ.

Cochrane Database Syst Rev 2000;(4):CD002854

BACKGROUND: Vitamin E is a dietary compound that functions as an antioxidant scavenging toxic free radicals. Evidence that free radicals may contribute to the pathological processes in Alzheimer's disease has led to interest in the use of vitamin E in the treatment of this disorder.

OBJECTIVES: To examine the effects of vitamin E treatment for people with Alzheimer's disease.

EARCH STRATEGY: The Cochrane Dementia Group Register of Clinical Trials was searched with the following terms: vitamin E, Alzheimer's disease, dementia, alpha-tocopherol, cognitive impairment, cognitive function and controlled trials. The latest search was carried out in July 2000.

SELECTION CRITERIA: All unconfounded, double blind, randomized trials in which treatment with vitamin E at any dose was compared with placebo for patients with Alzheimer's disease.

DATA COLLECTION AND ANALYSIS: Two reviewers independently applied the selection criteria an assessed study quality. One reviewer extracted and analysed the data. For each outcome measure data were sought on every patient randomized. Where such data were not available an analysis of patients who completed treatment was conducted.

MAIN RESULTS: Only one study was identified which met the inclusion criteria (Sano 1997). The primary outcome used in this study of 341 participants was survival time to the first of 4 endpoints, death, institutionalisation, loss of 2 out of 3 basic activities of daily living, or severe dementia, defined as a global Clinical Dementia Rating of 3. The investigators reported the total numbers in each group who reached the primary endpoint within two years for participants completing the study ("completers"). There appeared to be some benefit from vitamin E with fewer participants reaching endpoint - 58% (45/77) of completers compared with 74% (58/78) - a Peto odds ratio of 0.49, 95% confidence interval 0.25 to 0.96. However, more participants taking vitamin E suffered a fall (12/77 compared with 4/78; odds ratio 3.07, 95% CI 1.09 to 8.62). It was not possible to interpret the reported results for specific endpoints or for secondary outcomes of cognition, dependence, behavioural disturbance and activities of daily living.

REVIEWER'S CONCLUSIONS: There is insufficient evidence of efficacy of vitamin E in the treatment of people with with Alzheimer's disease. The one published trial of acceptable methodology (Sano 1997) was restricted to patients with moderate disease, and the published results are difficult to interpret. There is sufficient evidence of possible benefit to justify further studies. There was an excess of falls in the vitamin E group compared with placebo which requires further evaluation.

Huperzine A (shuangyiping): a promising drug for Alzheimer's disease.

Tang XC. Department of Pharmacology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China.

Zhongguo Yao Li Xue Bao 1996 Nov;17(6):481-4

Hup A, a novel alkaloid isolated from Chineses herb Huperzia serrata, is a potent and selective inhibitor of AChE, with a rapid absorption and penetration into the brain in experimental animals. The inhibition is reversible with a longer duration of action. Hup A exhibited memory-enhancing activities in a broad range of animal cognitive model. Compared to Phy, Tac, and Gal, Hup A has better therapeutic indices, and peripheral cholinergic side effects are minimal at therapeutic doses. These findings suggest that Hup A is a promising candidate for clinical development as a symptomatic treatment for AD.

[Cognitive enhancement effect of piracetam in patients with mild cognitive impairment and dementia]. [Article in Hungarian]

Tariska P, Paksy A Memoria Klinika, Orszagos Pszichiatriai es Neurologiai Intezet, Budapest.

Orv Hetil 2000 May 28;141(22):1189-93

Effectiveness and tolerability of two piracetam-containing drugs were compared in the frame of an open, multicentre, Phase-IV, prospective study with group and self control carried out in 9 Hungarian centres in 1998. Patients with cognitive decline from Alzheimer's disease and/or cerebrovascular origin have received the drug, in the first 4 weeks in 4800, later 2400 mg daily doses. One hundred four patients finished the study. No relevant difference with statistically significant degree was registered between the two groups. Based on this fact in this study data of the 104 patients were examined together. Authors examined two problems. The first: on which cognitive function is more effective the drug. Five factors of the modified Mini-Mental State Examination were separated and compared. Nearly all of them significantly increased especially the factors of memory, and concentration-psychomotor speed. The second examined field: are there certain subgroups with prognostic value about the effectiveness of piracetam treatment. Neither the duration of the illness, nor etiologic diagnosis, severity of cognitive decline, or former treatment with piracetam did influence significantly the efficacy. In case of depressive symptoms such connection was established: the more pronounced the severity of these symptoms the higher improvement can be expected in cognitive functions. This was also stressed by the logistic regression analysis. Authors described an original evaluation method of the trail-making test, which could widen the application of this popular test in psychopharmacologic studies. Final conclusions: the cognitive enhancer effect of piracetam appeared in a few weeks. This treatment could be effective even in Alzheimer's disease, in case of more pronounced cognitive decline, longer duration of the illness, and in case of former piracetam treatment as well. The degree of cognitive improvement was most pronounced in patients with comorbid depressive symptoms.

A 1-year controlled trial of acetyl-l-carnitine in early-onset AD.

Thal LJ, Calvani M, Amato A, Carta A. Department of Neurosciences, University of California-San Diego School of Medicine, La Jolla, CA 92093-0624, USA.

Neurology 2000 Sep 26;55(6):805-10

OBJECTIVE: To determine the efficacy of acetyl-l-carnitine (ALCAR) on the rate of decline in early-onset AD patients.

METHODS: A 1-year, multicenter, double-blind, placebo-controlled, randomized trial was conducted. Subjects were 45 to 65 years old, with a diagnosis of probable AD according to National Institute of Neurological Communicative Disorders-Alzheimer's Disease and Related Disorders Association criteria and had a Mini-Mental State Examination (MMSE) score between 12 and 26. They were treated with ALCAR (1 g tid) or placebo. Primary outcome measures were the Alzheimer's Disease Assessment Scale-Cognitive Component and the Clinical Dementia Rating Scale. Secondary measures included the ADAS Non-Cognitive Subscale, the MMSE, an Activities of Daily Living Scale (ADL), and a Clinician-Based Impression of Change (CIBIC).

RESULTS: Two-hundred twenty-nine patients were enrolled and randomized to drug treatment, with 117 taking placebo and 112 taking ALCAR. There were no significant differences between the two groups at baseline. For the primary outcome measures, there were no significant differences between the treatment groups on the change from baseline to endpoint in the intent-to-treat analysis. In the completer sample only, there was less deterioration in the MMSE for the ALCAR-treated subjects. There was no difference in rate of decline on the CIBIC and the ADL scale. There were no significant differences in the incidence of adverse events by treatment arm.

CONCLUSION: Overall, in a prospectively performed study in young-onset AD patients, ALCAR failed to slow decline. Less decline was seen on the MMSE in the completer sample only, with the difference being mediated by reducing decline in attention. A combination of ALCAR and a cholinesterase inhibitor should be tested for additivity.

Oral physostigmine and lecithin improve memory in Alzheimer disease.

Thal LJ, Fuld PA, Masur DM, Sharpless NS.

Ann Neurol 1983 May;13(5):491-6

Eight patients with early Alzheimer disease were treated with gradually increasing multiple daily doses of oral physostigmine and supplemental lecithin. Six individuals showed improvement in total recall and retrieval from long-term storage (LTR), with a decrease in intrusions (a measure of inaccurate recall). The optimal individual dose was either 2.0 or 2.5 mg of physostigmine for each responding patient. Results of this open trial were subsequently replicated during a double-blind crossover trial comparing physostigmine treatment to placebo. All six patients again demonstrated improvement in total recall and LTR, with a decrease in intrusions. The decrease in intrusions was strongly correlated with increasing inhibition of cholinesterase activity in cerebrospinal fluid, suggesting that the degree of improvement in the patient's memory was related to the amount of physostigmine that reached the brain. Other neurotransmitters and metabolites in cerebrospinal fluid were unaffected by the physostigmine therapy, suggesting a specific effect of physostigmine on the cholinergic system. The results suggest that small oral doses of physostigmine combined with lecithin ingestion have therapeutic benefit for some patients with Alzheimer disease.

Monoamine oxidase-B inhibitors in the treatment of Alzheimer's disease.

Thomas T Woodlands Medical and Research Center, 3150 Tampa Road, Oldsmar, FL 34677, USA.

Neurobiol Aging 2000 Mar-Apr;21(2):343-8

The monoamine oxidase-B (MAO-B) inhibitor L-deprenyl (Selegiline) is effective in treating Parkinson's disease and possibly Alzheimer's disease, with a concomitant extension of life span. It has been suggested that the therapeutic efficacy of L-deprenyl may involve actions other than the inhibition of the enzyme MAO-B. This article reviews some novel actions of L-deprenyl and suggests that stimulation of nitric oxide (NO) production could be central to the action of the drug. L-Deprenyl induced rapid increases in NO production in brain tissue and cerebral blood vessels. In vitro or in vivo application of L-deprenyl produced vasodilatation. The drug also protected the vascular endothelium from the toxic effects of amyloid-beta peptide. Because NO modulates activities including cerebral blood flow and memory, and reduced NO production has been observed in AD brain, stimulation of NO production by L-deprenyl could contribute to the enhancement of cognitive function in AD. MAO-B inhibitors are unique in that they exert protective effects on both vascular and neuronal tissue and thus warrant further consideration in the treatment of vascular and neurodegenerative diseases associated with aging.

[New hypothesis on etiopathogenesis of Alzheimer syndrome. Advanced glycation end products (AGEs)] [Article in German]

Thome J, Kornhuber J, Munch G, Schinzel R, Taneli Y, Zielke B, Rosler M, Riederer P. Psychiatrische Klinik und Poliklinik, Universitats-Nervenklinik, Wurzburg.

Nervenarzt 1996 Nov;67(11):924-9

Despite intense efforts, it has not yet been possible to clarify the etiopathogenesis of Alzheimer's dementia. There are, however, hypotheses which focus on certain aspects of this type of dementia, characterized by particular neuropathological alterations and clinical correlates. Recently, evidence has accumulated that advanced glycation endproducts (AGEs) could play an important role in the etiology of the Alzheimer's syndrome. AGEs are generated by an irreversible reaction through the non-enzymatic, long-term glycosylation of proteins. They are strongly resistant to proteolytic processes and induce protein crosslinking. They could thus inhibit the physiological functions of many proteins. Moreover, it is suggested that they contribute to the transformation of the soluble form of beta-amyloid into its unsoluble version. AGEs are also demonstrable in neurofibrillary tangles (NFTs). A further mechanism by which AGEs might be pathogenic is via their induction of oxidative stress. AGEs probably exert their pathological effects not only directly because of their chemical properties, but also by indirect receptor-mediated mechanisms. Further investigation of AGE-mediated mechanisms should reveal their role in the etiopathogenesis of the Alzheimer's syndrome and, finally, lead to the development of new pharmacological strategies aimed at inhibiting protein cross-linking.

Interactions between carnosine and zinc and copper: implications for neuromodulation and neuroprotection.

Trombley PQ, Horning MS, Blakemore LJ. Biomedical Research Facility, Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4340, USA.

Biochemistry (Mosc) 2000 Jul;65(7):807-16

This review examines interactions in the mammalian central nervous system (CNS) between carnosine and the endogenous transition metals zinc and copper. Although the relationship between these substances may be applicable to other brain regions, the focus is on the olfactory system where these substances may have special significance. Carnosine is not only highly concentrated in the olfactory system, but it is also contained in neurons (in contrast to glia cells in most of the brain) and has many features of a neurotransmitter. Whereas the function of carnosine in the CNS is not well understood, we review evidence that suggests that it may act as both a neuromodulator and a neuroprotective agent. Although zinc and/or copper are found in many neuronal pathways in the brain, the concentrations of zinc and copper in the olfactory bulb (the target of afferent input from sensory neurons in the nose) are among the highest in the CNS. Included in the multitude of physiological roles that zinc and copper play in the CNS is modulation of neuronal excitability. However, zinc and copper also have been implicated in a variety of neurologic conditions including Alzheimer's disease, Parkinson's disease, stroke, and seizures. Here we review the modulatory effects that carnosine can have on zinc and copper's abilities to influence neuronal excitability and to exert neurotoxic effects in the olfactory system. Other aspects of carnosine in the CNS are reviewed elsewhere in this issue.

Vitamin E supplementation prevents spatial learning deficits and dendritic alterations in aged apolipoprotein E-deficient mice.

Veinbergs I, Mallory M, Sagara Y, Masliah E. Departments of Neurosciences and Pathology, University of California, San Diego, School of Medicine, La Jolla, California 92093-0624, USA.

Eur J Neurosci 2000 Dec;12(12):4541-6

Recent studies have suggested that altered function of apolipoprotein E might lead to Alzheimer's disease via oxidative stress. In this context, the objective of this study was to determine if antioxidative treatment with vitamin E was neuroprotective in apolipoprotein E-deficient mice. For this purpose, 1-month-old control and apolipoprotein E-deficient mice received dietary vitamin E for 12 months. We showed that, compared to apolipoprotein E-deficient mice who received a regular diet, mice treated with vitamin E displayed a significantly improved behavioural performance in the Morris water maze. This improved performance was associated with preservation of the dendritic structure in vitamin E-treated apolipoprotein E-deficient mice. In addition, whilst untreated apolipoprotein E-deficient mice displayed increased levels of lipid peroxidation and glutathione, vitamin E-treated mice showed near normal levels of both lipid peroxidation and glutathione. These results support the contention that vitamin E prevents the age-related neurodegenerative alterations in apolipoprotein E-deficient mice.

The action of acetyl-L-carnitine on the neurotoxicity evoked by amyloid fragments and peroxide on primary rat cortical neurones.

Virmani MA, Caso V, Spadoni A, Rossi S, Russo F, Gaetani F. Research & Development Department, Sigma-tau HealthScience s.p.a., Via Treviso 4, 00040 Pomezia, Italy.

Ann N Y Acad Sci 2001 Jun;939:162-78

The amyloid beta-peptides have been implicated in the excitotoxic mechanism of neuronal injury in the pathogenesis of Alzheimer's disease. In this paper we examine the effect of different amyloid fragments (beta A1-40, A1-28, and A25-35), as well as potential neuroprotective compounds on rat cortical neuron viability. Exposure of neurones to beta A25-35 or A1-40 at concentrations as low as 1 microgram/ml inhibited, significantly, the MTT response and this level of inhibition was similar after 24-h or three-day exposure. Furthermore, the level of inhibition was not affected by the presence or absence of 5% horse serum in the medium. Preexposure (10 min) of neurones to ALC at concentrations of 0.1, 1, 5, and 10 mM attenuated the inhibition of the MTT response caused by beta A25-35 (50 micrograms/ml) in serum free medium for 24 h. The treatment of cells with vitamin E (100 microM), catalase (4 mg/ml), NGF (0.1 and 10 ng/ml), or cycloheximide (0.1 microgram/ml) significantly restored the MTT response that was inhibited by beta A25-35. The mechanism for the protective actions of these compounds against beta A25-35 toxicity is not clear but may involve free radical scavenger action and preservation of energy production, although other mechanisms, especially for ALC, such as a direct effect on A-beta interaction with charged anionic phospholipids and/or stabilizing action on membranes, are also possible.

Vitamin B(12) and folate in relation to the development of Alzheimer's disease.

Wang HX, Wahlin A, Basun H, Fastbom J, Winblad B, Fratiglioni L. Stockholm Gerontology Research Center and Division of Geriatric Medicine, NEUROTEC, Karolinska Institutet, Stockholm.

Neurology 2001 May 8;56(9):1188-94

OBJECTIVE: To explore the associations of low serum levels of vitamin B(12) and folate with AD occurrence.

METHODS: A population-based longitudinal study in Sweden, the Kungsholmen

PROJECT: A random sample of 370 nondemented persons, aged 75 years and older and not treated with B(12) and folate, was followed for 3 years to detect incident AD cases. Two cut-off points were used to define low levels of vitamin B(12) (< or =150 and < or =250 pmol/L) and folate (< or =10 and < or =12 nmol/L), and all analyses were performed using both definitions. AD and other types of dementia were diagnosed by specialists according to DSM-III-R criteria.

RESULTS: When using B(12) < or =150 pmol/L and folate < or =10 nmol/L to define low levels, compared with people with normal levels of both vitamins, subjects with low levels of B(12) or folate had twice higher risks of developing AD (relative risk [RR] = 2.1, 95% CI = 1.2 to 3.5). These associations were even stronger in subjects with good baseline cognition (RR = 3.1, 95% CI = 1.1 to 8.4). Similar relative risks of AD were found in subjects with low levels of B(12) or folate and among those with both vitamins at low levels. A comparable pattern was detected when low vitamin levels were defined as B(12) < or =250 pmol/L and folate < or =12 nmol/L.

CONCLUSIONS: This study suggests that vitamin B(12) and folate may be involved in the development of AD. A clear association was detected only when both vitamins were taken into account, especially among the cognitively intact subjects. No interaction was found between the two vitamins. Monitoring serum B(12) and folate concentration in the elderly may be relevant for prevention of AD.

Huperzine A improves cognitive deficits caused by chronic cerebral hypoperfusion in rats.

Wang LM, Han YF, Tang XC. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 200031, Shanghai, People's Republic of China.

Eur J Pharmacol 2000 Jun 9;398(1):65-72

The effects of (-)-huperzine A, a promising therapeutic agent for Alzheimer's disease, on learning behavior and on alterations of the cholinergic system, the oxygen free radicals and energy metabolites induced by permanent bilateral ligation of the common carotid arteries were investigated in rats. Daily oral administration of huperzine A produced a significant improvement of the deficit in the learning of the water maze task, beginning 28 days after ischemia, correlating to about 33-40% inhibition of acetylcholinesterase activity in cortex and hippocampus. Huperzine A significantly restored the decrease in choline acetyltransferase activity in hippocampus and significantly reduced the increases in superoxide dismutase, lipid peroxide, lactate and glucose to their normal levels. The present findings demonstrate that the improvement by huperzine A of the cognitive dysfunction in the late phase in chronically hypoperfused rats is due to its effects, not only on the cholinergic system, but also on the oxygen free radical system and energy metabolism. Our results strongly suggest that huperzine A has therapeutic potential for the treatment of dementia caused by cholinergic dysfunction and/or decrease of cerebral blood flow.

Functional imaging of the frontal lobes in organic dementia. Regional cerebral blood flow findings in normals, in patients with frontotemporal dementia and in patients with Alzheimer's disease, performing a word fluency test.

Warkentin S, Passant U. Department of Psychogeriatrics, University Hospital, Lund, Sweden.

Dement Geriatr Cogn Disord 1997 Mar-Apr;8(2):105-9

Patterns of functional cortical activation were studied by means of regional cerebral blood flow measurements, performed during rest and during a word fluency task in normal subjects (n = 22), in patients with Alzheimer's disease (n = 17), and in patients with frontotemporal dementia (n = 15). Although all groups showed a significant activation of the Broca's area during word production, the activation of the dorsolateral prefrontal cortex was clearly subnormal in both dementia groups. The frontal dysfunction was not explained by number of words produced, illness duration, or age. Thus, the results demonstrate that the word fluency task is a sensitive measure of frontal lobe function, and its incorporation in imaging studies may facilitate the detection of subtle functional impairment of the frontal lobes in organic dementia.

A controlled study of 2 doses of idebenone in the treatment of Alzheimer's disease.

Weyer G, Babej-Dolle RM, Hadler D, Hofmann S, Herrmann WM. Institute of Psychology, Johann Wolfgang Goethe University, Frankfurt/Main, Germany.

Neuropsychobiology 1997;36(2):73-82

Two doses of idebenone were studied in a prospective, randomized, double-blind, placebo-controlled multicentre study in patients suffering from dementia of the Alzheimer type (DAT) of mild to moderate degree. Diagnosis was based on DSM-III-R (primary degenerative dementia) and NINCDS-ADRDA criteria (probable Alzheimer's disease). A total of 300 patients were randomized to either placebo, idebenone 30 mg t.i.d. or 90 mg t.i.d. (n = 100, each) and treated for 6 months. The primary outcome measure was the total score of the Alzheimer's Disease Assessment Scale (ADAS-Total) at month 6. Secondary outcome measures were the ADAS cognitive (ADAS-Cog) and noncognitive scores (ADAS-Noncog), the clinical global response (CGI-Improvement), the MMSE, the Digit Symbol Substitution test (DSS) and several scales for the assessment of daily activities (the self- and observer-rating scales NAA and NAB of the Nuremberg Age Inventory NAI and Greene's Assessment). Safety parameters were adverse events, vital signs, ECG and clinical laboratory parameters. Clinical and psychometric evaluations were performed at baseline, and after 1, 3 and 6 months of treatment. After month 6 idebenone 90 mg t.i.d. showed statistically significant improvement in the primary efficacy variable ADAS-Total and in ADAS-Cog. An analysis of therapy responders performed for 3 outcome measures (CGI-global improvement, ADAS-Cog, ADAS-Noncog), selected to represent different domains of assessment, revealed significant superiority of idebenone 90 mg t.i.d. with respect to placebo in each of the 3 variables and in the concordance of responses across the 3 measures. Exploratory results for a subgroup of patients (ADAS-Total > or = 20) showed dose-related superiority of idebenone additionally on ADAS-Noncog and the CGI-Improvement scale. Safety results were inconspicuous for all assessments. The study results demonstrate the efficacy and safety of idebenone in the treatment of DAT patients.

Tryptophan degradation and immune activation in Alzheimer's disease.

Widner B, Leblhuber F, Walli J, Tilz GP, Demel U, Fuchs D. Institute of Medical Chemistry and Biochemistry, University of Innsbruck, Austria.

J Neural Transm 2000;107(3):343-53

Alzheimer's disease (AD) is likely associated with systemic immune activation. During immune response, interferon-gamma stimulates indoleamine 2,3-dioxygenase (IDO) converting tryptophan to N-formylkynurenine followed by kynurenine in an ensuing step. Thus, IDO activity is estimated by the kynurenine per tryptophan quotient (Kyn/Trp). In 21 patients suffering from AD, in 20 controls of similar age, and in 49 blood donors we measured serum tryptophan and kynurenine concentrations by HPLC. Lower tryptophan concentrations were found in elderly control subjects compared to blood donors (62.1 vs. 73.0 microM, p < 0.005). Tryptophan concentrations tended to be still lower in AD patients (54.4 microM, p = 0.07) compared to elderly controls. Enhanced tryptophan degradation in patients was reflected by significantly increased Kyn/Trp (46.1 vs. 34.1 in elderly controls, p < 0.05). Correlations were found in patients between Kyn/Trp and concentrations of soluble immune markers in serum, i.e., neopterin, interleukin-2 receptor and tumor necrosis factor receptor (all p < 0.001). Increased Kyn/Trp was associated with reduced cognitive performance. Tryptophan degradation due to immune activation may exert impact on the pathogenesis of AD.

Memantine in severe dementia: results of the 9M-Best Study (Benefit and efficacy in severely demented patients during treatment with memantine).

Winblad B, Poritis N. Karolinska Institutet, Department of Clinical Neuroscience and Family Medicine, Huddinge University Hospital, Sweden.

Int J Geriatr Psychiatry 1999 Feb;14(2):135-46

OBJECTIVES: To assess clinical efficacy and safety of memantine--an uncompetitive N-methyl-D-aspartate (NMDA) antagonist--in moderately severe to severe primary dementia.

MATERIALS AND METHODS: Dementia was defined by DSM-III-R criteria and severity was assessed by the Global Deterioration Scale (stages 5-7) and the Mini-Mental State Examination (< 10 points). Primary endpoints were the Clinical Global Impression of Change (CGI-C) rated by the physician, and the Behavioural Rating Scale for Geriatric Patients (BGP), subscore 'care dependence', rated by the nursing staff. Secondary endpoints included the modified D-Scale (Arnold/Ferm).

RESULTS: The ITT sample comprised 166 patients and 151 patients were treated per protocol. At 12-week ITT endpoint analysis, 82 received memantine 10 mg per day, 84 placebo. Dementia was in 49% of the Alzheimer type and in 51% of the vascular type (CT, Hachinski score). A positive response in the CGI-C was seen in 73% versus 45% in favour of memantine (stratified Wilcoxon p < 0.001), independent of the etiology of dementia. The results in the BGP subscore 'care dependence' were 3.1 points improvement under memantine and 1.1 points under placebo (p = 0.016). A coincident response of the two independent target variables was observed in 61.3% (memantine) versus 31.6% (placebo). Secondary endpoint analysis of the D-Scale assessing basic ADL functions support the primary results. Regarding the safety profile, no significant differences between treatment groups were observed.

CONCLUSIONS: The results of this trial support the hypothesis that memantine treatment leads to functional improvement and reduces care dependence in severely demented patients.

Aluminium and Alzheimer's disease.

Wisniewski HM, Wen GY. New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314.

Ciba Found Symp 1992;169:142-54; discussion 154-64

The hypothesis that aluminium (Al) is a cause of (or a risk factor in) the development of beta-amyloid plaques and neurofibrillary tangles (NFT) and dementia in Alzheimer's disease (AD) is based on studies by Wisniewski et al, Klatzo et al and Terry & Pena in 1965 that showed that injection of experimental animals with Al compounds induces the formation of NFT. Other publications revealed that Al affects cognitive functions in experimental animals and humans undergoing dialysis for renal failure. Electron probe and laser microprobe mass analysis (LAMMA) studies have demonstrated the presence of Al in NFT and cores of amyloid stars and nuclei of neurons in AD patients. Other studies have indicated the association between amyotrophic lateral sclerosis/Guam parkinsonism-dementia complex and Al in the environment. A recent report suggests that the chelating agent desferrioxamine slows the rate of cognitive decline in AD patients. Extensive studies of the pathology of AD and Al-induced encephalopathy by our group and others indicate that Al does not cause Alzheimer's disease neuropathology. However, under certain conditions, cognition can be affected when Al enters the brain. Therefore, for individuals with renal failure or undergoing dialysis or individuals with a damaged blood-brain barrier, the intake of Al should be controlled.

The efficacy of ginkgo for elderly people with dementia and age-associated memory impairment: new results of a randomized clinical trial

van Dongen MC, van Rossum E, Kessels AG, Sielhorst HJ, Knipschild PG Department of Epidemiology, Maastricht University, The Netherlands. [Record supplied by publisher]

J Am Geriatr Soc 2000 Oct;48(10):1183-94

OBJECTIVES: To evaluate the efficacy, the dose-dependence, and the durability of the effect of the ginkgo biloba special extract EGb 761 (ginkgo) in older people with dementia or age-associated memory impairment.

DESIGN: A 24-week, randomized, double-blind, placebo-controlled, parallel-group, multicenter trial.

SETTING: Homes for the elderly in the southern part of the Netherlands.

PARTICIPANTS: Older persons with dementia (either Alzheimer's dementia or vascular dementia; mild to moderate degree) or age-associated memory impairment (AAMI). 214 Participants were recruited from 39 homes for the elderly.

INTERVENTION: The participants were allocated randomly to treatment with EGb 761 (2 tablets per day, total dosage either 240 (high dose) or 160 (usual dose) mg/day) or placebo (0 mg/d). The total intervention period was 24 weeks. After 12 weeks of treatment, the initial ginkgo users were randomized once again to either continued ginkgo treatment or placebo treatment. Initial placebo use was prolonged after 12 weeks.

MEASUREMENTS: Outcomes were assessed after 12 and 24 weeks of intervention. Outcome measures included neuropsychological testing (trail-making speed (NAI-ZVT-G), digit memory span (NAI-ZN-G), and verbal learning (NAI-WL)), clinical assessment (presence and severity of geriatric symptoms (SCAG), depressive mood (GDS), self-perceived health and memory status (report marks)), and behavioral assessment (self-reported level of instrumental daily life activities).

RESULTS: An intention-to-treat analysis showed no effect on each of the outcome measures for participants who were assigned to ginkgo (n = 79) compared with placebo (n = 44) for the entire 24-week period. After 12 weeks of treatment, the combined high dose and usual dose ginkgo groups (n = 166) performed slightly better with regard to self-reported activities of daily life but slightly worse with regard to self-perceived health status compared with the placebo group (n = 48). No beneficial effects of a higher dose or a prolonged duration of ginkgo treatment were found. We could not detect any subgroup that benefited from ginkgo. Ginkgo use was also not associated with the occurrence of (serious) adverse events.

CONCLUSIONS: The results of our trial suggest that ginkgo is not effective as a treatment for older people with mild to moderate dementia or age-associated memory impairment. Our results contrast sharply with those of previous ginkgo trials.

Cholinesterase inhibitors and Gingko extracts--are they comparable in the treatment of dementia? Comparison of published placebo-controlled efficacy studies of at least six months' duration.

Wettstein A Stadtarztlicher Dienst, Zurich.

Phytomedicine 2000 Jan;6(6):393-401

The efficacy of four cholinesterase inhibitors (tacrine, donepezil, rivastigmine, metrifonate) and Ginkgo special extract EGb 761 in Alzheimer's disease were compared. The differences in the effects of the active substance and placebo on cognition were measured on the ADAS-Cog scale, taking into account the different degrees of dementia in the various studies and the dropout rate due to adverse drug reactions. Efficacy, expressed as the delay in symptom progression or the difference in response rate between active substance and placebo, showed no major differences between the four cholinesterase inhibitors and the Ginkgo special extract. Only tacrine exhibited a high dropout rate due to adverse drug reactions. In view of this, the subject of new prescriptions should be critically reviewed. Second-generation cholinesterase inhibitors (donepezil, rivastigmine, metrifonate) and Ginkgo special extract EGb 761 should be considered equally effective in the treatment of mild to moderate Alzheimer's dementia.

Efficacy of tablet huperzine-A on memory, cognition, and behavior in Alzheimer's disease.

Xu SS, Gao ZX, Weng Z, Du ZM, Xu WA, Yang JS, Zhang ML, Tong ZH, Fang YS, Chai XS, et al. Zhejiang Supervision and Detection Station of Drug Abuse, Zhejiang Medical University, Hangzhou, China.

Zhongguo Yao Li Xue Bao 1995 Sep;16(5):391-5

AIM: To evaluate the efficacy and safety of tablet huperzine-A (Hup) in patients with Alzheimer's disease.

METHODS: Using multicenter, prospective, double-blind, parallel, placebo controlled and randomized method, 50 patients were administered orally 0.2 mg (4 tablets) Hup and 53 patients were given po 4 tablets of placebo bid for 8 wk. All patients were evaluated with Wechsler memory scale, Hasegawa dementia scale, mini-mental state examination scale, activity of daily living scale, treatment emergency symptom scale, and measured with BP, HR, ECG, EEG, ALT, AKP, BUN, Cr, Hb, WBC, and urine routine.

RESULTS: About 58% (29/50) of patients treated with Hup showed improvements in their memory (P < 0.01), cognitive (P < 0.01), and behavioral (P < 0.01 functions. The efficacy of Hup was better than placebo (36%, 19/53) (P < 0.05). No severe side effect was found.

CONCLUSION: Hup is a promising drug for symptomatic treatment of Alzheimer's disease.

Estrogen therapy in postmenopausal women: effects on cognitive function and dementia.

Yaffe K, Sawaya G, Lieberburg I, Grady D. Department of Psychiatry, University of California, San Francisco 94121, USA.

JAMA 1998 Mar 4;279(9):688-95

CONTEXT: Several studies have suggested that estrogen replacement therapy in postmenopausal women improves cognition, prevents development of dementia, and improves the severity of dementia, while other studies have not found a benefit of estrogen use. OBJECTIVE: To determine whether postmenopausal estrogen therapy improves cognition, prevents development of dementia, or improves dementia severity. DATA SOURCES: We performed a literature search of studies published from January 1966 through June 1997, using MEDLINE, manually searched bibliographies of articles identified, and consulted experts.

STUDY SELECTION: Studies that evaluated biological mechanisms of estrogen's effect on the central nervous system and studies that addressed the effect of estrogen on cognitive function or on dementia.

DATA EXTRACTION: We reviewed studies for methods, sources of bias, and outcomes and performed a meta-analysis of the 10 studies of postmenopausal estrogen use and risk of dementia using standard meta-analytic methods.

DATA SYNTHESIS: Biochemical and neurophysiologic studies suggest several mechanisms by which estrogen may affect cognition: promotion of cholinergic and serotonergic activity in specific brain regions, maintenance of neural circuitry, favorable lipoprotein alterations, and prevention of cerebral ischemia. Five observational studies and 8 trials have addressed the effect of estrogen on cognitive function in nondemented postmenopausal women. Cognition seems to improve in perimenopausal women, possibly because menopausal symptoms improve, but there is no clear benefit in asymptomatic women. Ten observational studies have measured the effect of postmenopausal estrogen use on risk of developing dementia. Meta-analysis of these studies suggests a 29% decreased risk of developing dementia among estrogen users, but the findings of the studies are heterogeneous. Four trials of estrogen therapy in women with Alzheimer disease have been conducted and have had primarily positive results, but most have been small, of short duration, non-randomized, and uncontrolled.

CONCLUSIONS: There are plausible biological mechanisms by which estrogen might lead to improved cognition, reduced risk for dementia, or improvement in the severity of dementia. Studies conducted in women, however, have substantial methodologic problems and have produced conflicting results. Large placebo-controlled trials are required to address estrogen's role in prevention and treatment of Alzheimer disease and other dementias. Given the known risks of estrogen therapy, we do not recommend estrogen for the prevention or treatment of Alzheimer disease or other dementias until adequate trials have been completed.

Protective effects of idebenone and alpha-tocopherol on beta-amyloid-(1-42)-induced learning and memory deficits in rats: implication of oxidative stress in beta-amyloid-induced neurotoxicity in vivo.

Yamada K, Tanaka T, Han D, Senzaki K, Kameyama T, Nabeshima T. Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University School of Medicine, Japan.

Eur J Neurosci 1999 Jan;11(1):83-90

Amyloid beta-peptide (A beta), the major constituent of the senile plaques in the brains of patients with Alzheimer's disease, is cytotoxic to neurons and has a central role in the pathogenesis of the disease. Previous studies have suggested that oxidative stress is involved in the mechanisms of A beta-induced neurotoxicity in vitro. In the present study, we examined whether oxidative stress contributes to learning and memory deficits caused by continuous intracerebroventricular infusion of A beta-(1-42). In the A beta-(1-42)-infused rats, spontaneous alternation behaviour in a Y-maze and spatial memory in a water maze task were significantly impaired, as compared with A beta-(40-1)-infused control rats. The retention of passive avoidance learning was also significantly impaired by treatment with A beta-(1-42). Potent antioxidants idebenone and alpha-tocopherol prevented the behavioural deficits in Y-maze and water maze, but not passive avoidance, tasks in A beta-(1-42)-infused rats when they were repeatedly administered by mouth once a day from 3 days before the start of A beta infusion to the end of behavioural experiments. Lipid peroxide levels in the hippocampus and cerebral cortex of A beta-(1-42)-infused rats did not differ from those in control animals, and neither idebenone nor alpha-tocopherol affected the lipid peroxide levels. These results suggest that treatment with antioxidants such as idebenone and alpha-tocopherol prevents learning and memory deficits caused by A beta.

Orally active NGF synthesis stimulators: potential therapeutic agents in Alzheimer's disease.

Yamada K; Nitta A; Hasegawa T; Fuji K; Hiramatsu M; Kameyama T; Furukawa Y; Hayashi K; Nabeshima T Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University School of Medicine, Japan.

Behav Brain Res (Netherlands) Feb 1997, 83 (1-2) p117-22

The degeneration of cholinergic neurons may be responsible for cognitive impairment in patients with Alzheimer's disease (AD). Since nerve growth factor (NGF) plays an important role in the survival and maintenance of cholinergic neurons in the central nervous system, this factor may have some beneficial effects on the cognitive impairment observed in patients with AD. However, since NGF does not cross the blood-brain barrier and is easily metabolized when administered peripherally, it can only be used when directly injected into the brain. In this review, we show that repeated oral administration of the NGF synthesis stimulators, idebenone and propentofylline, partially restored the age-associated decrease of NGF in the frontal and parietal cortices. Furthermore, this treatment attenuated the impairment of performance in the water maze, passive avoidance, and habituation tasks in rats with bilateral forebrain lesions, and in rats which had received continuous infusion of anti-NGF antibody into the septum. The behavioral improvement induced by idebenone and propentofylline was accompanied by recovery of both the reduced activity of choline acetyltransferase and the changes in [3H]QNB binding. These results suggest that the use of NGF synthesis stimulators may provide a novel therapeutic approach to cholinergic dysfunction. (32 Refs.) (NOTE: Idebenone and propentophylline are drugs that can be ordered from offshore pharmacies.)

Free radicals and lipid peroxidation do not mediate beta-amyloid-induced neuronal cell death.

Yao ZX, Drieu K, Szweda LI, Papadopoulos V. Division of Hormone Research, Departments of Cell Biology and Pharmacology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20007, USA.

Brain Res 1999 Nov 20;847(2):203-10

"beta Amyloid (Abeta)-induced free radical-mediated neurotoxicity" is a leading hypothesis as a cause of Alzheimer's disease (AD). Abeta increased free radical production and lipid peroxidation in PC12 nerve cells, leading to increased 4-hydroxy-2-nonenal (HNE) production and modification of specific mitochondrial target proteins, apoptosis and cell death. Pretreatment of the cells with isolated ginkgolides, the anti-oxidant component of Ginkgo biloba leaves, or vitamin E, prevented the Abeta-induced increase of reactive oxygen species (ROS). Ginkgolides, but not vitamin E, inhibited the Abeta-induced HNE modification of mitochondrial proteins. However, treatment with these anti-oxidants did not rescue the cells from Abeta-induced apoptosis and cell death. These results indicate that free radicals and lipid peroxidation may not mediate Abeta-induced neurotoxicity.

The Ginkgo biloba extract EGb 761 rescues the PC12 neuronal cells from beta-amyloid-induced cell death by inhibiting the formation of beta-amyloid-derived diffusible neurotoxic ligands.

Yao Z, Drieu K, Papadopoulos V. Division of Hormone Research, Departments of Cell Biology, Pharmacology, and Neuroscience, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20007, USA.

Brain Res 2001 Jan 19;889(1-2):181-90

beta Amyloid (Abeta) treatment induced free radical production and increased glucose uptake, apoptosis and cell death in PC12 nerve cells. Addition of the standardized extract of Ginkgo biloba leaves, EGb 761 together with the Abeta protein prevented, in a dose-dependent manner, the Abeta-induced free radical production, increased glucose uptake, apoptosis and cell death. However, pretreatment of the cells with EGb 761 did not rescue the cells from the Abeta-induced toxicity although it prevented the Abeta-induced reactive oxygen species generation. Moreover, the terpene and flavonoid-free EGb 761 extract, HE 208, although inhibited the Abeta-induced increased glucose uptake, it failed to protect the cells from apoptosis and cytotoxicity induced by Abeta. In conclusion, these results indicate that the terpenoid and flavonoid constituents of EGb 761, acting probably in combination with components present in HE 208, are responsible for rescuing the neuronal cells from Abeta-induced apoptosis and cell death; their mechanism of action being distinct of their antioxidant properties. Because pre- and post-treatment with EGb 761 did not protect the cells from Abeta-induced neurotoxicity, we examined whether EGb 761 interacts directly with Abeta. Indeed, in vitro reconstitution studies demonstrated that EGb 761 inhibits, in a dose-dependent manner, the formation of beta-amyloid-derived diffusible neurotoxic soluble ligands (ADDLs), suggested to be involved in the pathogenesis of Alzheimer's disease.

Alzheimer's amyloid beta-peptide associated free radicals increase rat embryonic neuronal polyamine uptake and ornithine decarboxylase activity: protective effect of vitamin E.

Yatin SM, Yatin M, Aulick T, Ain KB, Butterfield DA. Department of Chemistry, Sanders-Brown Center of Aging, University of Kentucky, Lexington 40506-0055, USA.

Neurosci Lett 1999 Mar 19;263(1):17-20

Recent evidence indicates that alterations in brain polyamine metabolism may be critical for nerve cell survival after a free radical initiated neurodegenerative process. It has been shown previously that A beta(1-42) and A beta(25-35) are toxic to neurons through a free radical dependent oxidative mechanism. Treatment of rat embryonic hippocampal neuronal cultures with A beta-peptides increased ornithine decarboxylase (ODC) activity and spermidine uptake, suggesting that oxidative stress upregulates the polyamine mechanism for the repair of free radical damage. Pretreatment of the cells with vitamin E prior to A beta exposure decreased ODC activity and spermidine uptake to control level. This study is the first to demonstrate that A beta treated cells show an increased polyamine metabolism in response to free radical mediated oxidative stress and that the free radical scavenger vitamin E prevents these attenuations. These results are discussed with reference to Alzheimer's disease.

Essential fatty acids preparation (SR-3) improves Alzheimer's patients quality of life.

Yehuda S, Rabinovtz S, Carasso RL, Mostofsky DI. Department of Psychology Bar-Ilan University, Ramat Gan, Israel.

Int J Neurosci 1996 Nov;87(3-4):141-9

In a number of previous reports we showed the salutary effects on rats of SR-3, a compound comprising a 1:4 ratio of n-3 and n-6 fatty acids. Improvements were noted in learning tasks, thermoregulation, recovery from neurotoxins, and seizure protection. Because we were impressed that these effects are related to changes in membrane fluidity and neuronal functioning and because Alzheimer's Disease is also associated with lipid defects, we undertook a short term (4 week) double blind study with 100 Alzheimer patients (60 received SR-3 and 40 in a placebo control). The results indicated improvements in mood, cooperation, appetite, sleep, ability to navigate in the home, and short term memory. Overall improvement was reported for 49 patients, and in no case did a guardian report adverse effects to the compound. While not uniform or permanent, and while no mode of action for SR-3 can be precisely identified at this time, the promising results in quality of life for the patient and caregiver warrant further clinical trials and continued basic research into the neuropsychological substrate of the disease and its response to SR-3.

Essential fatty acids and the brain: possible health implications.

Youdim KA, Martin A, Joseph JA. Laboratory of Neuroscience, United States Department of Agriculture, Jean Mayer Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.

Int J Dev Neurosci 2000 Jul-Aug;18(4-5):383-99

Linoleic and alpha-linolenic acid are essential for normal cellular function, and act as precursors for the synthesis of longer chained polyunsaturated fatty acids (PUFAs) such as arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), which have been shown to partake in numerous cellular functions affecting membrane fluidity, membrane enzyme activities and eicosanoid synthesis. The brain is particularly rich in PUFAs such as DHA, and changes in tissue membrane composition of these PUFAs reflect that of the dietary source. The decline in structural and functional integrity of this tissue appears to correlate with loss in membrane DHA concentrations. Arachidonic acid, also predominant in this tissue, is a major precursor for the synthesis of eicosanoids, that serve as intracellular or extracellular signals. With aging comes a likely increase in reactive oxygen species and hence a concomitant decline in membrane PUFA concentrations, and with it, cognitive impairment. Neurodegenerative disorders such as Parkinson's and Alzheimer's disease also appear to exhibit membrane loss of PUFAs. Thus it may be that an optimal diet with a balance of n-6 and n-3 fatty acids may help to delay their onset or reduce the insult to brain functions which these diseases elicit.

Reactive oxygen species-induced apoptosis in PC12 cells and protective effect of bilobalide.

Zhou LJ, Zhu XZ Department of Pharmacology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences.

J Pharmacol Exp Ther 2000 Jun;293(3):982-8

Although clinical studies have demonstrated that EGb 761, a standard extract of Ginkgo biloba, was effective in mild-to-moderate dementia of the Alzheimer's disease patients, the mechanism underlying its neuroprotective effect remains unclear. In this study, effects of bilobalide, the main constituent of the nonflavone fraction of EGb 761, on reactive oxygen species (ROS)-induced apoptosis in PC12 cells was studied. Exposure of cells to xanthine (100 microM)/xanthine oxidase (150 mU/ml) (ROS producer) resulted in a characteristic DNA fragmentation and an increase in the apoptosis rate. When p53, c-Myc, Bcl-2, Bcl-x(L), and Bax were measured by flow cytometry and the activities of caspase-1- and caspase-3-like protease determined with Ac-YVAD-AMC or Ac-DEVD-AMC as substrates, the profile of ROS-induced changes in these apoptosis regulatory and effector proteins suggests that elevation of c-Myc, p53, and Bax and activation of caspase-3 play an important role in the apoptosis. When cells were treated with ROS and bilobalide (25-100 microM) simultaneously, a dose-dependent reduction in the apoptotic rate was found. The percentage of cells with positive staining for c-Myc and p53 decreased from 27.8 and 50.1% to 16.7 and 23.2%, respectively, when bilobalide (25 microM) was present. Bilobalide also reduced ROS-induced elevation of Bax and activation of caspase-3 effectively. Our results provide the first direct evidence that bilobalide can protect neurons against oxidative stress. Bilobalide may block the apoptosis in the early stage and then attenuate the elevation of c-Myc, p53, and Bax and activation of caspase-3 in cells.

Idebenone - monograph.


Altern Med Rev 2001 Feb;6(1):83-6

No abstract available Full page editorial found here

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