Effect of donepezil in Alzheimer disease can be measured by a computerized human analog of the Morris water maze.

BACKGROUND: Drug development for Alzheimer disease (AD) is challenged by the success in animal models tested in the Morris water maze (MWM) and the subsequent failures to meet primary outcome measures in phase II or III clinical trials in patients. The human variant of MWM (hMWM) enables us to examine allocentric and egocentric navigation as in the MWM. OBJECTIVE: It was the aim of this study to examine the utility of a computerized hMWM to assess the effects of donepezil in mild AD. METHODS: Donepezil 5 mg/day was started after initial hMWM testing in the treated group (n = 12), and after 28 days, the dose was increased to 10 mg/day. The performance after 3 months was compared to that of a non-treated group (n = 12). RESULTS: Donepezil stabilized or improved the spatial navigation performance after 3 months, especially in the allocentric delayed recall subtask (p = 0.014). CONCLUSIONS: The computerized hMWM has the potential to measure the effects of donepezil in mild AD. It is a sensitive cognitive outcome measure in AD clinical trials.

Commentary to the recently published review "Drug pipeline in neurodegeneration based on transgenic mice models of Alzheimer's disease" by Li, Evrahimi and Schluesener. Ageing Res. Rev. 2013 Jan;12(1):116-40.

Li and colleagues summarized the most frequently used Alzheimer's disease (AD) mouse models available for drug testing and the mediating effects of the different compounds. With almost 300 cited publications, authors present the research community's effort of the last 10 years in finding a new drug for the treatment of AD. Some of the transgenic mouse lines mentioned by Li and colleagues are discussed only very briefly. Since we are convinced that a couple of these models indeed have a great value for AD research and the development of new AD drugs we will subsequently describe a few of them in more detail. A suitable mouse model of AD does not only have to mimic major hallmarks of AD that are modifiable by different test substances as mentioned by the authors; they also have to be translational to clinical trials in humans. For the following discussion, we will therefore also include information on clinical trials of drugs previously tested in the different transgenic mice.

Low oxygen tension enhances hepatitis C virus replication.

Low oxygen tension exerts a significant effect on the replication of several DNA and RNA viruses in cultured cells. In vitro propagation of hepatitis C virus (HCV) has thus far been studied under atmospheric oxygen levels despite the fact that the liver tissue microenvironment is hypoxic. In this study, we investigated the efficiency of HCV production in actively dividing or differentiating human hepatoma cells cultured under low or atmospheric oxygen tensions. By using both HCV replicons and infection-based assays, low oxygen was found to enhance HCV RNA replication whereas virus entry and RNA translation were not affected. Hypoxia signaling pathway-focused DNA microarray and real-time quantitative reverse transcription-PCR (qRT-PCR) analyses revealed an upregulation of genes related to hypoxic stress, glycolytic metabolism, cell growth, and proliferation when cells were kept under low (3% [vol/vol]) oxygen tension, likely reflecting cell adaptation to anaerobic conditions. Interestingly, hypoxia-mediated enhancement of HCV replication correlated directly with the increase in anaerobic glycolysis and creatine kinase B (CKB) activity that leads to elevated ATP production. Surprisingly, activation of hypoxia-inducible factor alpha (HIF-α) was not involved in the elevation of HCV replication. Instead, a number of oncogenes known to be associated with glycolysis were upregulated and evidence that these oncogenes contribute to hypoxia-mediated enhancement of HCV replication was obtained. Finally, in liver biopsy specimens of HCV-infected patients, the levels of hypoxia and anaerobic metabolism markers correlated with HCV RNA levels. These results provide new insights into the impact of oxygen tension on the intricate HCV-host cell interaction.

Elevated levels of soluble total and hyperphosphorylated tau result in early behavioral deficits and distinct changes in brain pathology in a new tau transgenic mouse model.

Tauopathies, characterized by hyperphosphorylation and aggregation of tau protein, include frontotemporal dementias and Alzheimer's disease. To explore disease mechanisms and investigate potential treatments, we generated a transgenic (tg) mouse line overexpressing human tau441 with V337M and R406W mutations. Biochemical characterization of these TMHT (Thy-1 mutated human tau) mice showed a significant increase in human transgene expression relative to endogenous murine tau by Western blot and multi-array immunosorbent assay. Only soluble total tau and phosphorylated tau (ptau at residue Thr(181), Ser(199), Thr(231) and Thr(235)), but not insoluble total tau and ptau were increased. Application of the Phospho-Tau SRM assay revealed that phosphorylation at Ser(396) and Ser(404) in soluble tau in the presence of the R406W mutation was at baseline levels in the cortex of TMHT mice compared to non-tg littermates. Histological analyses showed a progressive increase in human tau protein in the amygdala over age, while hippocampal tau levels remained constant from 2 months onwards. Behavioral testing of TMHT mice in the Morris water maze revealed a distinct progressive spatial learning impairment starting already at 5 months of age. Furthermore, we showed that the TMHT mice have early olfactory deficits. These impairments are unbiased by any motor disturbance or lack of motivation. Our results prove that combination of the V337M and R406W mutations of tau accelerates human tau phosphorylation and induces tau pathology as well as cognitive deficits, making this model a suitable tool for basic research on tau as well as in vivo drug testing.

Longitudinal magnetization transfer imaging in mild to severe Alzheimer disease.

BACKGROUND AND PURPOSE: MTI has been proposed as a sensitive technique for studying microstructural brain tissue changes in patients with AD, but the course of these changes over time is largely unknown. We therefore used a placebo-controlled study of memantine to follow the evolution of tissue damage in AD by means of MTR measurements and investigated how MTR changes were related to brain atrophy and cognition. MATERIALS AND METHODS: Twenty-eight patients (76.5 ± 5.8 years) with mild to moderate AD underwent MTI, brain volume measurements, and cognitive testing at baseline and after 6 and 12 months. Nineteen healthy individuals (73.3 ± 3.2 years) served as controls. MTI was performed with a 2-minute protocol that was optimized for an enhanced MT effect and reduced motion sensitivity. Global and regional MTR measurements served as correlations with brain volumes and the MMSE score. RESULTS: AD patients had significantly lower global MTR values than controls, and showed a consistent and significant MTR reduction in all regions investigated over a period of 12 months. These MTR changes were paralleled by a brain tissue loss of 2.2% per year. Associations between MTR and cognition were found for the hippocampus, putamen, and thalamus, and were more pronounced in the left hemisphere. CONCLUSIONS: MTI in AD allows the assessment of ongoing global and regional brain damage independent of atrophy, and therefore appears to be a valuable marker for disease-related tissue changes.

Seroprevalence of Histomonas meleagridis in pullets and laying hens determined by ELISA.

Serum samples from 1120 layers from 56 flocks and 400 pullets from 20 flocks were tested by an indirect sandwich ELISA to investigate the prevalence of antibodies to Histomonas meleagridis in chickens kept in alternative husbandry systems. The overall prevalence of antibodies to H meleagridis in layers was 37.3 per cent, and positive birds were identified in 50 flocks. This was significantly higher than in pullets, where only 8.3 per cent of the birds tested positive. Optical density (OD) values obtained from pullet sera were much lower than the OD values from layers; however, positive birds were detected in half of the pullet flocks. In particular, all birds from an organic pullet flock were found to be positive, with high OD values. Overall, the highest prevalence of positive sera was obtained from birds kept in free-range flocks. Attempts to reisolate live histomonads from birds in 18 layer flocks were unsuccessful.

Oral vaccination of 1-day-old turkeys with in vitro attenuated Histomonas meleagridis protects against histomonosis and has no negative effect on performance.

One-day-old turkey poults were vaccinated against histomonosis (syn. histomoniasis) via the oral route by application of in vitro attenuated Histomonas meleagridis. Subsequently, two different groups composed of 14 birds each were challenged cloacally with highly virulent histomonads after 2 or 4 weeks. Two additional groups of non-vaccinated birds were infected with the challenge inoculum at the same time points. In addition, a group of 19 birds, of which 14 were vaccinated but not challenged, were kept for clinical and serological examinations. Non-vaccinated and non-challenged birds (n=10) represented the negative control group. All non-vaccinated but infected birds and 10 out of 14 vaccinated turkeys challenged 2 weeks post vaccination (w.p.v.) contracted severe histomonosis. Turkeys challenged 4 w.p.v. and all remaining birds used in this experiment did not show any pathognomonic clinical signs. In addition, no adverse effect regarding the weight gain could be observed in birds that were vaccinated but not challenged. The excretion of attenuated and virulent live histomonads was observed very infrequently by re-isolation, but transmission to in-contact birds was very efficient. Presence of antibodies was first noticed 3 w.p.v. and antibody levels remained above the cut-off value until termination of the experiment at 16 w.p.v. The present experiment demonstrates for the first time the potential efficacy of in vitro attenuated histomonads used as an orally applied vaccine to 1-day-old turkeys for protection against fatal histomonosis without affecting performance.

Experimental infection of chickens with Histomonas meleagridis confirms the presence of antibodies in different parts of the intestine.

Specific pathogen-free chickens were infected with a clonal culture of the protozoan parasite, Histomonas meleagridis. Severe lesions were found within the caeca of all birds euthanized at 7 and 14 days post-infection (d.p.i.). Following necropsy of birds, intestinal samples were taken to establish ex vivo tissue cultures to determine the IgG, IgA and IgM antibody levels in the supernatants before and after incubation with a recently established ELISA. Presence of antibodies was also determined in the sera and first optical density values for IgG above the cut-off were detected at 14 d.p.i. IgA levels remained low in the serum with a small peak 4 weeks p.i., a phenomenon also found for IgM. The intestinal tissue samples showed very strong immunological reactions in the parasitized caeca with an initial peak of IgM, high levels of IgG and a continuous increase of IgA. In the duodena and jejuna, IgA values reached similar high levels as those obtained in the caeca, whereas IgG and IgM increased only slightly.

Randomized, crossover, single-blind, placebo-controlled, human pharmacology clinical trial with desoxypeganine, a new cholinesterase and selective MAO-A inhibitor: multiple-dose pharmacokinetics.

UNLABELLED: Desoxypeganine, a naturally occurring alkaloid, is being developed for its potential utility in the pharmacological treatment of alcohol abuse to reduce craving and depression in alcohol abusers, and might also be useful as a smoking cessation aid. During the preclinical development it was characterized as a cholinesterase inhibitor, acting preferentially on butyrylcholinesterase, and as a selective inhibitor of monoamine oxidase A but not monoamine oxidase B. OBJECTIVE: The aim of the present human pharmacology clinical trial was to assess the oral bioavailability, pharmacokinetic profile and tolerability of desoxypeganine, administered in a multiple-dose regimen to healthy volunteers. SUBJECTS AND METHODS: Eighteen healthy adult volunteers of both sexes received placebo, 50 mg and 100 mg desoxypeganine (b.i.d. for 3 days) in a single-blind, crossover, randomized manner. Main pharmacokinetic parameters after single and multiple doses were estimated. Clinical tolerability and clinical laboratory safety, including effect on QTc interval, were assessed. RESULTS: Non-compartmental estimations of Cmax, AUC, tmax, t1/2 and MRT at 12-h intervals are given. No significant dose effect was observed in tmax, t1/2 and MRT. Cmax and AUC are approximately double with the dose of 100 mg comparing with the dose of 50 mg. A significant increase (p < 0.05) on Cmax and AUC was also obtained with the highest dose administered in comparison with the lowest one, revealing a slight but clinically insignificant accumulation. Steady state of drug concentration was reached in both genders during the study period. Plasma protein binding of desoxypeganine amounted to approximately 18%. No severe adverse events were recorded and none of the subjects suffered from any adverse event that led to withdrawal from the study. Most frequently recorded adverse event was dizziness. No significant effects of desoxypeganine on vital signs, laboratory parameters or QTc interval were observed. CONCLUSIONS: The present clinical trial describes the pharmacokinetic profile of two doses of desoxypeganine, administered orally in multiple dose to healthy volunteers. The drug was well tolerated without any severe clinical, clinical laboratory, or ECG adverse events being recorded.

CHF5074, a novel gamma-secretase modulator, attenuates brain beta-amyloid pathology and learning deficit in a mouse model of Alzheimer's disease.

BACKGROUND AND PURPOSE: We evaluated the effects of 1-(3',4'-dichloro-2-fluoro[1,1'-biphenyl]-4-yl)-cyclopropanecarboxylic acid (CHF5074), a new gamma-secretase modulator, on brain beta-amyloid pathology and spatial memory in transgenic mice expressing the Swedish and London mutations of human amyloid precursor protein (hAPP). EXPERIMENTAL APPROACH: Sixty 6-month-old hAPP mice were treated for 6 months with CHF5074 or ibuprofen (375 ppm in the diet) or standard diet. Twenty-one wild-type mice received standard diet. KEY RESULTS: Compared with transgenic controls, CHF5074 treatment significantly reduced the area occupied by plaques in cortex (P = 0.003) and hippocampus (P = 0.004). The number of plaques were also reduced by CHF5074 in both cortex (P = 0.022) and hippocampus (P = 0.005). Plaque-associated microglia in CHF5074-treated animals was lower than in transgenic controls in cortex (P = 0.008) and hippocampus (P = 0.002). Ibuprofen treatment significantly reduced microglia area in cortex and hippocampus but not beta-amyloid burden. On the last day of the Morris water maze, transgenic controls performed significantly worse than the non-transgenic animals and the CHF5074-treated transgenic mice, on the swimming path to reach the hidden platform. Ibuprofen-treated animals did not perform significantly better than transgenic controls. CONCLUSIONS AND IMPLICATIONS: Chronic CHF5074 treatment reduced brain beta-amyloid burden, associated microglia inflammation and attenuated spatial memory deficit in hAPP mice. This novel gamma-secretase modulator is a promising therapeutic agent for Alzheimer's disease.

Establishing an indirect sandwich enzyme-linked-immunosorbent-assay (ELISA) for the detection of antibodies against Histomonas meleagridis from experimentally infected specific pathogen-free chickens and turkeys.

No serological method suitable for large screening of antibodies against Histomonas meleagridis in poultry is available so far, the objective targeted in the present investigation. Consequently, an ELISA was developed as a suitable tool for this purpose. Investigating serum samples from non-infected specific pathogen-free (spf) chickens and commercial turkeys a high-background signal was noticed when ELISA plates were directly coated with purified parasitic cells. This signal was significantly reduced by coating the plates with a polyclonal rabbit antibody, raised against histomonads, prior to the addition of the antigen. Adopting this approach five antigen preparations were compared and a high reproducibility could be demonstrated reflected by a very low coefficient of variation of 5.3% and 1.7% for the chicken and turkey sera, respectively. After this initial development all further experiments were carried out with one set of plates and the same antigen preparation. Investigating chicken sera obtained from birds infected at 14 days of life, OD values above a predetermined cut-off value were observed 2 weeks post-infection and a rise of IgG antibodies was noticed until 6 weeks post-infection, when the experiment was terminated. Non-protected turkeys infected at 6 weeks of age displayed an increasing IgG response until 14 days post-infection, prior to the death of animals due to histomonosis. In comparison, the majority of turkeys vaccinated with attenuated histomonads, obtained through prolonged passaging and challenged 4 weeks later with virulent parasites, displayed a demonstrable antibody response after the challenge only. Antibody titres increased until 4 weeks post-challenge when the birds were killed and the study was terminated. Altogether, the developed indirect sandwich ELISA proved to be a quick and efficient method to detect IgG antibodies against H. meleagridis in sera of experimentally infected chickens and turkeys and will be a helpful tool to obtain more insights into the epidemiology of the parasite and the immune response of its hosts.

Longitudinal multimodal imaging in mild to moderate Alzheimer disease: a pilot study with memantine.

OBJECTIVE: To study the feasibility of multimodal neuroimaging in mild to moderate Alzheimer disease (AD) and to estimate the size of possible treatment effects of memantine on potential functional, structural and metabolic biomarkers of disease progression. METHODS: In this randomised, double-blind, placebo-controlled pilot study, 36 patients with moderate AD received 52 weeks of memantine (20 mg/day) or placebo. Patients were re-evaluated after 26 and 52 weeks to measure the change from baseline in several outcome measures including global and regional glucose metabolism, total brain and hippocampal volumes, as well as chemical shift imaging-derived global and regional N-acetylaspartate and myoinositol concentrations. RESULTS: In the total population, global glucose metabolism decreased by 2.3% (p<0.01), total brain volume by 2.1% (p<0.001) and hippocampal volume by 2.7% (p<0.01) after 52 weeks. Chemical shift imaging (CSI) spectra were severely affected by patient-induced artefacts and highly variable. Patients receiving memantine showed less decline in glucose metabolism in all brain areas than patients on placebo. Their loss of hippocampal volume was substantially smaller (2.4% vs 4.0%). No between-group differences were seen for changes in total brain volume. CONCLUSIONS: The results support the use of multimodal imaging including MRI and positron emission tomography (PET) to monitor the progression of moderate AD. CSI yielded unreliable longitudinal results. The data suggest that memantine has potentially protective effects in AD and they can be used for planning larger confirmatory studies on the cerebral effects of memantine.

Phase I clinical trial with desoxypeganine, a new cholinesterase and selective MAO-A inhibitor: tolerance and pharmacokinetics study of escalating single oral doses.

Desoxypeganine (DOP) is a natural alkaloid that has been characterized as a cholinesterase inhibitor and a selective inhibitor of monoamine oxidase A. DOP has been investigated for its potential utility in the pharmacological treatment of alcohol abuse and as a smoking cessation aid. The aim of this clinical trial was to evaluate the tolerance and single-dose pharmacokinetic profile of DOP in healthy human volunteers. The study was an open-label, dose-escalation, phase I clinical trial involving the administration of increasing single oral doses of DOP (50, 100, 150 and 200 mg). The study was conducted according to the Declaration of Helsinki and Good Clinical Practice. Eighteen healthy adult volunteers (8 males and 10 females, age ranging 20-30 years) were recruited. DOP was administered sequentially, escalating in single doses of 50, 100, 150 and 200 mg in four experimental sessions with a washout period of at least 1 week between them. Progress to the next dose was allowed only if the previous dose was tolerated. Pharmacokinetic parameters were determined using noncompartmental methods. Clinical and analytical safety was assessed throughout the study, and QTc intervals were measured at regular intervals. The main pharmacokinetic parameters and renal excretion are described. No serious adverse events were registered, and none of the subjects discontinued the study because of lack of tolerance. All the adverse events recorded were mild to moderate and increased with the dose. The ECG measurements revealed that even at a higher dose, the QTc interval remained below the safety threshold. In summary, this first phase I study indicates that DOP has linear and dose-proportional pharmacokinetics, satisfactory oral bioavailability and plasma half-life and renal excretion. Also, DOP has shown an adequate safety profile that allows the continuation of clinical development.

The role of alpha-synuclein in neurodegenerative diseases: a potential target for new treatment strategies?

Alpha-synuclein (AS) is the main constituent of Lewy bodies. There is an ongoing discussion if overexpression is already dangerous, or if toxicity is subjected to oligomers, protofibrils or mature aggregates. The facts that the central hydrophobic part of AS is also a constituent of amyloid plaques in Alzheimer's disease (AD) and that a majority of patients have Lewy bodies and Lewy neurites in specific brain areas raised our interest in the contribution of AS to AD pathogenesis. The N-terminal amino acid sequence 1-15 of beta-synuclein (BS) seems to be a natural antiaggregation factor for AS. We synthesized a library with different sequence variations. Several of these peptides displayed neuroprotective activity in tissue culture models of neurodegeneration induced by oxidative stress or beta-amyloid 1-42. In spite of the fact that these peptides have a short half-life, a significant in vivo reduction in brain plaque load and improvement of behavior was demonstrated in amyloid precursor protein transgenic mice after intranasal treatment for 2 months. KEGV, the shortest sequence, was also active after intraperitoneal application. The in vitro effects cannot be explained by the antiaggregatory potential, but most likely by interaction of BS derivates with antiapoptotic PI3/Akt or antioxidative pathways. The possibility that BS-derived peptidomimetics act as neuroprotectants and prevent protein misfolding suggests therapeutic usefulness.

Is alpha-synuclein pathology a target for treatment of neurodegenerative disorders?

Alpha-synuclein is the main constituent of intra-neuronal Lewy bodies, which are characteristic of Parkinson's disease, but aggregates are also found as axonal inclusions. Alpha-synuclein pathology is found together with beta-amyloid plaques and neurofibrillary tangles in Alzheimer's disease and other neurodegenerative disorders. In spite of the fact that the biological function of this synaptic protein is not known so far, there is an increasing body of evidence indicating an interaction with amyloid peptides, but also with tau-hyperphosphorylation. A high proportion of alpha-synuclein purified from Lewy bodies is phosphorylated on Ser129. There are still different opinions about the toxicity of the alpha-synuclein aggregates. Alpha-synuclein seems to influence different intracellular signaling pathways which are in direct relation to defense mechanisms against reactive oxygen species or apoptosis. It is obvious that overproduction of alpha-synuclein, but also different mutations, are inducing the formation of aggregates. Because of the possible link to neurodegeneration, different attempts have been made to counteract alpha-synuclein aggregation. An interesting approach is utilizing beta-synuclein, a biological factor, with an aminoacid sequence closely resembling that of alpha-synuclein. Proof of concept studies indicated that overexpression of beta-synuclein is able to counteract alpha-synuclein aggregation in a transgenic animal model, while also ameliorating functional deficits. As an alternative approach, the use of low molecular beta-synuclein N-terminal peptide derivatives has been considered. Several of these structures displayed clear neuroprotective activities in tissue culture models of neurodegeneration, including beta-amyloid toxicity. Therefore it has been speculated that these compounds might have a broad therapeutic efficacy in different neurodegenerative disorders. A proof of concept study in hAPP-transgenic animals resulted in a highly significant decrease in beta-amyloid plaque load, an increase in soluble beta-amyloid peptides and a decrease in insoluble forms. There was also significant improvement of cognitive deficits in this APP transgenic mouse model following intranasal but also peripheral treatment with three of these compounds. From this study it is concluded that the observed effects of the peptides derived from beta-synuclein N-terminus are depending on both, a direct interaction with aggregation of proteins, but also with stimulation of anti-apoptotic and anti-oxidative intracellular signaling pathways.

Neuroprotection of cerebrolysin in tissue culture models of brain ischemia: post lesion application indicates a wide therapeutic window.

All attempts to reduce neuronal damage after acute brain ischemia by the use of neuroprotective compounds have failed to prove efficacy in clinical trials so far. One of the main reasons might be the relatively narrow time window for intervention. In this study 2 different tissue culture models of ischemia, excitotoxic lesion by the use of glutamate and oxygen-glucose deprivation (OGD), were used to investigate the effects of delayed application of Cerebrolysin (Cere) on neuronal survival. This drug consists of low molecular weight peptides with neuroprotective and neurotrophic properties similar to naturally occurring growth factors. After both types of lesion, acute as well as delayed treatment with Cere resulted in a dose dependent and significant rescue of neurons. In the model of excitotoxic cell death significant drug effects were found even when the treatment started with a delay of 96 hours after addition of glutamate. In the OGD model pronounced effects were found after 48 hours delay of treatment, and even after 72 hours a small but significant rescue of neurons was detected. The neuroprotective effects of a single addition of Cerebrolysin to the culture medium resulted in significant protection until end of the experiments which was up to 2 weeks after the initial lesion. A shift of the efficacious dosages from low to high concentrations indicates that most likely active compounds are used up, indicating that multiple dosing might even increase the effect size. In conclusion the results indicate that Cere displays a relatively wide therapeutic time window which might be explained by a combination of acute neuroprotective properties and neurotrophic efficacy.

A peptide preparation protects cells in organotypic brain slices against cell death after glutamate intoxication.

Cerebrolysin has been shown to have neurotrophic and neuroprotective potential similar to NGF or BDNF. In the present study organotypic brain slices were utilized to determine the neuroprotective effects of Cerebrolysin, in a glutamate lesion paradigm mimicking a key event in ischemia. The study focused on the effects of Cerebrolysin on both necrotic and apoptotic cell death. Two specific DNA intercalating dyes were used to distinguish the type of cell death. The drug effect was evaluated both microscopically and quantitatively before, 24 hours after and then again 8 days after the lesion. Cerebrolysin was added either before and after the lesion or after the lesion only. The most pronounced effect was seen with the drug added both prior to and after the glutamate lesioning. A treatment after the lesion only also counteracted necrosis and apoptosis. The results render the drug relevant for treating acute as well as chronic neurodegenerative diseases.

Neuropeptide dietary supplement N-PEP-12 enhances cognitive function and activates brain bioelectrical activity in healthy elderly subjects.

N-PEP-12 is a dietary supplement consisting of neuropeptides and amino acids. In animal experiments, the compound has been shown to enhance cognitive function and reduce neurodegenerative events associated with aging. In this study, we investigated the effects of a single oral dose of N-PEP-12 (180 mg) on brain bioelectrical activity and cognitive performance in healthy elderly subjects. N-PEP-12 induced a significant (p < 0.05) increase in relative alpha-activity power 6 h after administration. This enhancement was accompanied by a generalized decrease in slow Delta-activity. Significant improvement in memory performance subtests was also seen 6 h after N-PEP-12 administration in some but not in all tests. Taken together, these data suggest that N-PEP-12 might be a reliable dietary supplement to be investigated for improving and, perhaps, maintaining brain function among healthy older adults.

N-PEP-12--a novel peptide compound that protects cortical neurons in culture against different age and disease associated lesions.

The neuroprotective potency of N-PEP-12, a novel, proprietary compound consisting of biopeptides and amino acids was investigated. Lesion models have been applied in neuronal cultures of embryonic chicken cortex, pre-treated with N-PEP-12 from the first day onwards. On day 8 in vitro neurons were lesioned and cell viability was measured 24 and 48 hours later. To simulate acute brain ischemia, cytotoxic hypoxia was induced by sodium cyanide or by iodoacetate and excitotoxicity by L-glutamate. Ionomycin for up to 48 hours induced calcium overload. The cytoskeleton was disrupted by addition of colchicine. N-PEP-12 shows dose-dependent neuroprotection in all different models. The effect size depends on the recovery time but also on the extent of the lesion. In cases of mild to moderate lesion pronounced dose-dependent effects could be demonstrated. This indicates that chronic exposure to N-PEP-12 is able to prevent neuronal cell death associated to conditions occurring during normal aging and neurological disorders like ischemic stroke, hypoxia, brain trauma, or AD.

Amelioration of the cerebrovascular amyloidosis in a transgenic model of Alzheimer's disease with the neurotrophic compound cerebrolysin.

Increased production and reduced clearance of amyloid beta (Abeta) plays a central role in the pathogenesis of Alzheimer's disease (AD). We have recently shown that the neurotrophic peptide mixture Cerebrolysin (Cbl) has the ability of improving synaptic functioning and reducing amyloid deposition in a transgenic (tg) animal model of Alzheimer's disease (AD). Since in AD, potentially toxic Abeta aggregates accumulate not only around neurons but also in the blood vessels, then it is important to investigate whether bioactive compounds such as Cbl might have the capacity to ameliorate the age-related cerebral amyloid angiopathy (CAA) in tg models. To this end, tg mice expressing mutant human amyloid precursor protein (APP) under the Thy1 promoter were treated with Cbl or saline alone starting at 7 or 12 months of age for a total of three months. Neuropathological analysis with an antibody against Abeta showed that Cbl decreased amyloid deposition around the blood vessels in a time dependent manner. These effects were accompanied by a reduction in perivascular microgliosis and astrogliosis and increased expression of markers of vascular fitness such as CD31 and ZO-1. No lymphocytic infiltration was observed associated with Abeta in the vessels. Consistent with these findings, ultrastructural analysis showed that while in tg mice treated with saline alone there was an abundant accumulation of amyloid fibers in the vascular wall accompanied by thickening of the basal membrane and endothelial cell damage, in Cbl-treated mice there was considerable reduction in the subcellular alterations of endothelial and smooth muscle cells with preservation of basal membranes and intercellular junctions. Taken together, these results suggest that Cbl treatment might have beneficial effects in patients with cognitive impairment due to cerebrovascular amyloidosis by reducing Abeta accumulation and promoting the preservation of the cerebrovasculature.