alzheimers-disease

Matchynski JJ, Lowrance SA, Rossignol J, Dekorver NW, Puckett ND, Pappas CA, Trainor KJ, Delongchamp JL, Radwan J, Heldt JC, Dey ND, Dunbar GL (2010) The effects of a combination of antioxidants and essential fatty acids as treatment for Alzheimer’s disease in the mu-p75 saporin-injected model. Neuroscience 2010 Abstracts 856.15/I21. Society for Neuroscience, San Diego, CA.

Summary: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is marked by a progressive loss of memory and affects over five million people nationwide (Alzheimer’s Association, 2010). It is characterized by an increase in oxidative stress, amyloid plaques, neurofibrillary tangles, and the loss of cholinergic neurons. Mice injected with the ribosome deactivating protein, mu-p75 saporin, model the deficits in memory, loss of cholinergic neurons, and increased oxidative stress observed in AD. The current study aimed to decrease the deficits observed in the saporin mouse model using a combination of antioxidants from tart cherries and essential fatty acids, Cerise© total body rhythm (TBR). Mice dosed with TBR or methylcellulose were given bilateral ventricular injections of phosphate buffer saline or saporin. Memory and motor functioning were then measured in a series of behavioural tests. Results indicate that TBR decreased the memory deficits observed in object recognition, place recognition, and Morris-water-maze tasks, as well as the inflammatory response and loss of cholinergic neurons in the medial septum. The findings suggest that TBR could provide an effective, adjunctive treatment that may delay the onset or decrease the severity of AD.

Related Products: mu p75-SAP (Cat. #IT-16)

Lowrance SA, Matchynski JJ, Rossignol J, Dekorver N, Fink K, Salibi P, Dunbar GL (2010) Krx-0501 reduces cognitive deficits in a saporin mouse model of Alzheimer’s disease. Neuroscience 2010 Abstracts 856.8/I14. Society for Neuroscience, San Diego, CA.

Summary: Alzheimer’s disease (AD) is a progressive neurodegenerative disease marked by memory loss and dysfunction of cholinergic neurons. Neurotrophic factors, like nerve growth factor (NGF), have shown to improve cognitive function in AD patients. The inability of NGF to cross the blood brain barrier (BBB) and painful side effects have caused serious concerns over its future use as a treatment. Substituted pyrimidines, such as KRX-0501 (KRX; Keryx Biopharmaceuticals, New York, NY) on the other hand, readily cross the BBB and exert beneficial neurotrophic-like effects in vivo. In this study KRX was administered daily to mice that were given intra-cerebroventricular injections of mu p-75 Saporin (SAP; Advanced Targeting Systems, San Diego, CA) or vehicle (phosphate buffered saline). KRX treatment began at seven weeks of age and continued for 32 days. Doses were set at 10, 15, and 20mg/kg respectively. Animals were tested for cognitive impairment using the Morris water maze (MWM) task, object recognition (OR) and place recognition (PR) tasks while motor deficits were tested using MWM swim speed, rotarod (RR) and the open field (OF) tasks. On day 33 of KRX treatment, mice were sacrificed by transcardial perfusion. In a second experiment, mice received SAP or vehicle surgery and were sacrificed for enzyme-linked immunosorbent assay (ELISA) analysis. MWM results revealed significantly lower escape latencies of control animals relative to SAP animals. In addition mice treated with the low and middle doses of KRX displayed decreased escape latency on the MWM. In the OR task, only mice in the highest treatment group performed significantly above chance levels. No between group differences were seen in the PR task, swim speed, latency to fall from the RR, and distance travelled in the OF. Immunohistochemistry (IHC) using the glial fibrillary acidic protein antibody indicated that astrocyte activation took place primarily around the surgical injection sites. IHC labeling against choline-acetyltransferase revealed a significant decrease in cholinergic neurons of the medial septum. Finally, ELISA protein analysis of midbrain sections revealed that the KRX treatments did not increase levels of endogenous NGF. These results show that SAP injections produced a reproducible destruction of cholinergic neurons, accompanied by memory deficits in the MWM, in the absence of motoric deficits. The KRX treatment attenuated memory deficits, despite unabated cholinergic cell loss in the medial septum, and did so without affecting levels of endogenous NGF.

Related Products: mu p75-SAP (Cat. #IT-16)

Hammond R, Shinde A, Gibbs RB (2010) Effects of basal forebrain cholinergic lesions and estradiol on relative levels of estrogen receptor mRNAs in the rat forebrain. Neuroscience 2010 Abstracts 611.16/MMM67. Society for Neuroscience, San Diego, CA.

Summary: Beneficial effects of estradiol on cognitive performance are lost in response to cholinergic denervation of the hippocampus and frontal cortex. Effects of estradiol also decline with age and time following the loss of ovarian function, which parallels naturally-occurring declines in basal forebrain cholinergic function. We hypothesize that cholinergic impairment may alter the expression of estrogen receptors in specific regions of the brain, thereby decreasing estradiol effects. In the present study, quantitative RT-PCR was used to evaluate the effects of septal cholinergic lesions ± estradiol treatment on relative levels of three estrogen receptors, ERα, ERß, and GPR30. Young adult ovariectomized (OVX) rats received intraseptal injections of saline or 192 IgG-saporin (a selective cholinergic immunotoxin). One week later, rats received either silastic capsules containing 17ß-estradiol or a blank capsule, implanted s.c. Seven days later, rats were killed and the brains were dissected. Tissues from the hippocampus, frontal cortex, prefrontal cortex, striatum, and septum were collected. RNA was extracted and relative levels of ER mRNA determined. Levels within each sample were normalized to levels of GAPDH. Differences between treatments and controls were calculated using the ΔΔCt method. Preliminary data indicate that septal cholinergic lesions produced significant decreases in relative levels of ERα and ERß mRNA in the hippocampus, and an increase in ERß mRNA in the frontal cortex. Estradiol alone produced decreases in levels of ERα, ERß, and GPR30 mRNA in the frontal cortex, decreased levels of ERα and ERß mRNA in the septum, and increased levels of ERα mRNA in the striatum. In rats with cholinergic lesions that also received estradiol, decreased levels of ERα mRNA were detected in hippocampus and septum, and decreased levels of ERß mRNA also were detected in septum. Data suggest that some of the effects of cholinergic denervation on ER mRNA expression may be mitigated by estradiol treatment. These data show that cholinergic lesions significantly affect ER mRNA expression in the brain, and that effects are region-specific. Such effects could account for the loss of beneficial effects of estradiol on cognitive performance in association with age and time following menopause, as well as in association with specific neurodegenerative diseases such as Alzheimer’s disease.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Gibbs RB, Chipman AM, Nelson D (2010) Donepezil enhances effects of estradiol on DMP acquisition in rats with partial loss of septal cholinergic neurons. Neuroscience 2010 Abstracts 710.23/NNN23. Society for Neuroscience, San Diego, CA.

Summary: We hypothesize that effects of estradiol on cognitive performance decrease in association with decreased basal forebrain cholinergic function, and that this accounts for the loss of estradiol effect with age and time post-menopause. In the present study, we tested the feasibility of using donepezil, a cholinesterase inhibitor commonly used to treat Alzheimer’s disease, to enhance beneficial effects of estradiol on cognitive performance in rats with septal cholinergic lesions. Young adult, ovariectomized rats received intraseptal injections of 192IgG-saporin or vehicle. Two weeks later, rats started receiving daily injections of donepezil (Don, 5 mg/Kg/day, i.p.) or vehicle. A week later, rats received either silastic capsules containing 17ß-estradiol (E) or empty capsules, implanted s.c. Rats were then trained on a delayed matching-to-position (DMP) T-maze task. Upon completion, brains were collected and sections through the medial septum were processed for detection of choline acetyltransferase (ChAT). The severity of the cholinergic lesions was ranked on a 5-point scale by estimating the loss of ChAT-positive cells in the septum. Eighty-one rats completed the study. Lesions produced a decline in performance that correlated with the severity of cholinergic cell loss (F[4,76]=10.0, p<0.0001). In rats with >50% loss of septal cholinergic neurons, treating with E and/or Don had no significant effect on the rate of DMP acquisition (F[3,36]=0.90, p=0.45). In rats with <50% loss of septal cholinergic neurons, treating with the combination of Don+E significantly increased the rate of acquisition relative to controls (p<0.05 by Tukey test), and reduced deficits associated with increasing the intertrial delay (F[9, 111]=2.30, p=0.02 for Delay x Tx interaction). Treating with Don or E alone had no significant effect, although E alone produced a strong trend toward improvement. Cholinergic lesions also increased the likelihood that rats would adopt a persistent turn χ2=13.3, p=0.0003), and treatment with Don+E reduced this effect (χ2=8.8, p=0.03). These findings demonstrate that cholinergic dysfunction produces a learning impairment as well as a loss of estrogen effect on cognitive performance which can be attenuated by treating with a cholinesterase inhibitor. The findings also indicate a critical threshold for cholinergic function below which combined therapy is not effective. We propose that combining donepezil with estrogen therapy in postmenopausal women may offer significant cognitive benefits, particularly in relatively healthy older women showing early signs of cognitive impairment or Alzheimer’s disease.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Liu Y, Krencik R, Liu H, Ma L, Zhang X, Zhang S-C (2010) Functional cholinergic neurons from human embryonic stem cells. Neuroscience 2010 Abstracts 331.5/B19. Society for Neuroscience, San Diego, CA.

Summary: Basal forebrain cholinergic neurons play a critical role in regulating memory and cognition. Degeneration or dysfunction of these neurons is associated with neurological conditions including Alzheimer’s disease and dementia. In this study, we aimed at generating cholinergic neurons from human embryonic stem cells (hESCs) for therapeutic development. hESCs were first differentiated to primitive neuroepithelial cells in a chemically defined medium. In the presence of sonic hedgehog, over 97% of the differentiated cells became Nkx2.1-expressing ventral forebrain progenitors. These ventral progenitors further differentiated to cholinergic neurons with basal forebrain characteristics by expressing ChAT, VAChAT, FoxG1, Nkx2.1, Islet1, ßIII-tubulin, MAP2, P75, Synapsin but not GABA, Glutamate, or Mash2. The hESC-generated cholinergic neurons were electrophysiologically active in vitro. Following transplantation into the hippocampus of mice, in which cholinergic neurons in the medial septum were destroyed by IgG-P75-saporin, the grafted human cells produced large cholinergic neurons. The animals transplanted with cholinergic neurons demonstrated an improvement in learning and memory deficit. These results indicate that the human stem cell-generated cholinergic neurons are functional, thus providing a new source for drug discovery and cell therapy for neurological disorders that affect cholinergic neurons.

Related Products: mu p75-SAP (Cat. #IT-16)

ATS Poster of the Year Winner

Rennie KE, Frechette M, Pappas BA (2010) The effects of neonatal cholinergic lesion on age-related changes in behaviour, neurogenesis and CA1 pyramidal cell morphology. Neuroscience 2010 Abstracts 349.8/J12. Society for Neuroscience, San Diego, CA.

Summary: Age-related cognitive decline is associated with dysfunction of the basal forebrain cholinergic (BFC) system, and cortico-hippocampal cholinergic denervation is a hallmark neurochemical feature of the Alzheimer’s-afflicted brain. It has been suggested that cognitive deficits that emerge with age may be rooted in early dysfunction of the BFC system and that impaired cholinergic transmission might interact with ageing-associated factors to produce cognitive decline. The purpose of this study was to examine the effects of neonatal cholinergic lesion on age-related changes in spatial working memory, neurogenesis and hippocampal CA1 pyramidal cell morphology. We have previously reported that neonatal cholinergic lesion results in only minor behavioural deficits, but impairs the birth and/or survival of new neurons and reduces CA1 dendritic complexity in the young adult rat. We hypothesized that memory impairments would become apparent in lesioned rats as they age, and that this impairment would be accompanied by more drastic reductions in neurogenesis and cytoarchitectural alterations than those that have been documented in the young adult animal after neonatal cholinergic lesion. Seven-day-old male Sprague-Dawley rats were subjected to basal forebrain cholinergic lesion by infusion of the cholinotoxin 192-IgG-Saporin into the lateral ventricles. At the age of 12 or 21 months, the rats were tested on a working memory version of the Morris water maze. While aging had only a slight effect on the memory performance of control rats, lesioned rats showed pronounced memory impairments with age. This occurred without CA1 cell loss or astrogliosis in 21-month-old lesioned rats when compared to age-matched controls. However, golgi analysis revealed that while cholinergic lesion did not alter the total dendritic length, branching, number of spines, or spine density of CA1 pyramidal cells in 21-month-old rats, the distribution of these parameters across branch orders was shifted. The lesion caused a slight reduction in apical branch length and spine density, and basal branch number, length and number of spines at low/middle branch orders, but increased these parameters at upper branch orders. Thus, perinatal cholinergic lesion precipitates spatial memory dysfunction during old age, and this seems to be associated with cytoarchitectural changes to neurons rather than neuronal loss.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Jeong D, Lee D, Chang J (2010) Decrease of Arc protein expression and delay of memory acquisition by immunolesion. Neuroscience 2010 Abstracts 145.5/H6. Society for Neuroscience, San Diego, CA.

Summary: Cholinergic neuronal deficit is one of the common characteristics in both Alzheimer’s disease dementia (AD) and vascular dementia (VaD). Forebrain Cholinergic neurons in the basal forebrain project to the neocortex and the hippocampus which make an important role in memory function. We used 192 IgG-saporin to produce selective lesion of cholinergic basal forebrain neurons including the medial septum (MS) and the nucleus basalis magnocellularis (NBM). We intracerebroventricularly injected 192 IgG-saporin (0.63 µg/µl dose, 6 µl, 8 µl and 10 µl) or phosphate buffered saline (8 µl). Morris water maze and tissue perforation for immunohistochemistry and western blotting were sequentially performed 2 weeks after injection of 192 IgG-saporin. In the acquisition phase of Morris water maze, latency of 6ul group (2nd day), 8 µl group (2nd day) and 10 µl group (3rd day) was significantly delayed but it was recovered within 1week. Time in platform and the number of crossing were significantly different between 8 µl LV injection group and sham group in probe test. In immunohistological study, the extent of the cholinergic lesion was showed in the basal forebrain complex region of all 192 IgG-saporin injected rats. Expression of Arc protein is significantly decreased in the frontal cortex (8 µl and 10 µl groups) but hippocampus. Decrease of parvalbumin in the frontal cortex (8ul and 10 ul groups) and the hippocampus (10 µl) means nonselective lesion because of high dose of immunotoxin. We observed recovery after memory acquisition delay and decrease of synaptic activity in the frontal cortex except in the hippocampus. High dose of immunotoxin injured not only cholinergic neuron but also GABAergic neuron in the frontal cortex and the hippocampus. Hippocampal GABAergic cell synapse on to glutamatergic pyramidal cells. Deficit of the hippocampal inhibitory cell may facilitate hippocampal synaptic plasticity and the recovery.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Szot P, Franklin A, White S, Raskind M (2010) Time- and dose-response of 6-hydroxydopamine on locus coeruleus noradrenegric neurons in c57bl/6 mice. Neuroscience 2010 Abstracts 157.20/R1. Society for Neuroscience, San Diego, CA.

Summary: Locus coeruleus (LC) noradrenergic neurons are severely reduced in Alzheimer’s and Parkinson’s disease. However, it is unclear why these neurons are lost and the consequence of this loss on the progression and symptoms of these neurodegenerative disorders. Therefore, establishing an animal model of LC noradrenergic neuronal loss is critical in determining how the LC contributes to these disorders. The purpose of this study was to determine the dose- and time-response of noradrenergic neurotoxicity of 6-hydroydopamine (6OHDA) in adult male C57BL/6 mice. Our laboratory recently demonstrated that DSP4 does not result in a loss of LC noradrenergic neurons. Neurotoxicity of 6OHDA on LC noradrenergic neurons was determined by measuring tyrosine hydroxylase (TH) mRNA expression and TH-immunoreactivity (IR) in LC noradrenergic neurons. TH mRNA was quantitated using MCID (OD), while TH-IR was used to determine if protein levels reflected what was observed with mRNA. 6OHDA (20 µg/µl bilaterally) and dopamine beta-hydroxylase-saporin (DBH-saporin; 1 µg/µl bilaterally) were initially administered into the lateral ventricles (icv) and sacrificed 2 weeks later. 6OHDA reduced TH mRNA and -IR in both the dopaminergic neurons of the substantia nigra (SNpc) and ventral tegmental nucleus (VTA), and LC by -46%, -65% and -63%, respectively. DBH-saporin icv injection did not affect dopaminergic or noradrenergic neurons. Injection of DBH-saporin into the LC (0.1 µg/µl unilaterally) also did not affect LC noradrenergic neurons 2 weeks later. As a time-course 6OHDA (7 µg/µl) was injected unilaterally into the LC (vehicle was administered in the alternate LC) and sacrificed 3 days, 2 and 3 weeks later. A loss of LC noradrenergic neurons was observed only 3 weeks later (-81.4%). 6OHDA was then injected unilaterally into the LC at 7, 10, and 14 ug/ul (vehicle was administered in the alternate LC) and sacrificed 2 weeks later. The 7 µg/µl dose of 6OHDA did not affect TH mRNA in the LC as compared to control side (-19%), 10 ug/ul 6OHDA significantly reduced TH mRNA in the LC by ~55%, and 14 ug/ul 6OHDA dramatically reduced TH mRNA in the LC by ~90%. TH-IR in the LC of the three different 6OHDA doses reflected closely the TH mRNA data. 6OHDA at the dose of 14 µg/µl, which resulted in a near complete loss of LC noradrenergic neurons, did not affect dopaminergic neurons in the SN (-9%) and VTA (+17%). These data indicate that DBH-saporin, at the parameters studied, did not affect mouse LC noradrenergic neurons. 6OHDA demonstrated a time- and dose-response reduction of mouse LC noradrenergic neurons. The consequence of this LC neuronal loss on forebrain noradrenergic markers will also be presented.

Related Products: Anti-DBH-SAP (Cat. #IT-03)

Klinkenberg I, Blokland A (2010) The validity of scopolamine as a pharmacological model for cognitive impairment: A review of animal behavioral studies. Neurosci Biobehav Rev 34(8):1307-1350. doi: 10.1016/j.neubiorev.2010.04.001 PMID: 20398692

Objective: To provide an overview is given of the effects of scopolamine on animal behavior.

Summary: The most important and influential articles over the past 40 years are included in the present review. The cholinergic hypothesis of memory function as originally put forward by Bartus et al. (1982) has undergone a revision after several lesion studies were performed which used the highly specific cholinergic toxin 192 IgG-SAP (Wiley et al., 1995).

Related Products: 192-IgG-SAP (Cat. #IT-01)

See Also:

• Chudasama Y et al. Cholinergic modulation of visual attention and working memory: Dissociable effects of basal forebrain 192-IgG-saporin lesions and intraprefrontal infusions of scopolamine. Learn Mem 11(1):78-86, 2004.
• Wiley RG et al. Destruction of the cholinergic basal forebrain using immunotoxin to rat NGF receptor: modeling the cholinergic degeneration of Alzheimer’s disease. J Neurol Sci 128:157-166, 1995.
• Wiley RG et al. Immunolesioning: Selective destruction of neurons using immunotoxin to rat NGF receptor. Brain Res 562:149-153, 1991.
• Wrenn CC et al. The behavioral functions of the cholinergic basal forebrain: lessons from 192 IgG-saporin. Int J Dev Neurosci 16(7-8):595-602, 1998.
• Wenk GL The nucleus basalis magnocellularis cholinergic system: one hundred years of progress. Neurobiol Learn Mem 67(2):85-95, 1997.
• Baxter MG et al. Intact spatial learning in both young and aged rats following selective removal of hippocampal cholinergic input. Behav Neurosci 110:460-467, 1996.
• Baxter MG et al. Intact spatial learning in both young and aged rats following selective removal of hippocampal cholinergic input. Behav Neurosci 110:460-467, 1996.
• Baxter MG et al. Disruption of decrements in conditioned stimulus processing by selective removal of hippocampal cholinergic input. J Neurosci 17:5230-5236, 1997.
• Chiba AA et al. Selective removal of cholinergic neurons in the basal forebrain alters cued target detection. Neuroreport 10(14):3119-3123, 1999.
• McGaughy J et al. Effects of chlordiazepoxide and scopolamine, but not aging, on the detection and identification of conditional visual stimuli. J Gerontol A Biol Sci Med Sci 50(2):B90-B96, 1995.
• McGaughy J et al. Crossmodal divided attention in rats: effects of chlordiazepoxide and scopolamine. Psychopharmacology (Berl) 115(1-2):213-220, 1994.
• Torres EM et al. Behavioral, histochemical and biochemical consequences of selective immunolesions in discrete regions of the basal forebrain cholinergic system. Neuroscience 63:95-122, 1994.
• Voytko ML Cognitive functions of the basal forebrain cholinergic system in monkeys: memory or attention?. Behav Brain Res 75(1-2):13-25, 1996.

De Bartolo P, Cutuli D, Ricceri L, Gelfo F, Foti F, Laricchiuta D, Scattoni ML, Calamandrei G, Petrosini L (2010) Does age matter? Behavioral and neuro-anatomical effects of neonatal and adult basal forebrain cholinergic lesions. J Alzheimers Dis 20:207-227. doi: 10.3233/JAD-2010-1355 PMID: 20164586

Summary: The authors characterized the differences caused by age on the effect of cholinergic lesions of the basal forebrain. Seven-day-old rats received 210 ng bilateral intracerebroventricular injections of 192-IgG-SAP (Cat. #IT-01). Eighty-day-old rats received 4 µg bilateral intracerebroventricular injections of 192-IgG-SP. Both experimental groups displayed similar behavior, indicating that development of a depleted cholinergic system yields similar results to cholinergic dysfunction in adulthood.

Related Products: 192-IgG-SAP (Cat. #IT-01)