alzheimers-disease

Lowrance S, Matchynski J, Rossignol J, Dekorver N, Sandstrom M, Dunbar G (2012) CXB-909 attenuates cognitive deficits in the mu-p-75 saporin mouse model of Alzheimer’s disease. Neuroscience & Medicine 3(1):65-68. doi: 10.4236/nm.2012.31010

Summary: CXB-909 is a small molecule NGF amplifier that has been shown to enhance neurite outgrowth in various neuronal cell lines. This type of molecule has potential therapeutic use in disorders such as Alzheimer’s disease. In this work the authors lesioned cholinergic cells in the basal forebrain of mice with bilateral 0.8 μg intracerebroventricular injections of mup75-SAP (Cat. #IT-16). Lesioned animals performed significantly worse than controls in a water maze task. Lesioned animals subsequently treated with CXB-909 displayed improved performance, indicating that CXB-909 can attenuate memory deficits caused by loss of cholinergic input.

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

Lee J, Jeong D, Chang J (2011) The effects of basal forebrain cholinergic neuron on novel object recognition. Neuroscience 2011 Abstracts 878.10. Society for Neuroscience, Washington, DC.

Summary: Medial septum and basal nucleus areas of the basal forebrain project cholinergic neurons to the frontal cortex and the Hippocampus.And degeneration of the cholinergic basal forebrain neurons is a common feature of Alzheimer’s disease (AD) has been correlated with cognitive decline. This research was studied to verify the effects of cholinergic neuron in basal forebrain to the role of the hippocampus and the frontal cortex on recognition through recognition test and immunohistochemistry after damaging cholinergic neuron of the basal forebrain by intraventricular injection of 192 IgG-saporin. 192 IgG-saporin of 8ul (0.63ug/ul) was injected to the bilateral lateral ventricle of rats. After 2 weeks, novel object recognition (NOR) test was conducted to elucidate damage of cholinergic neuron. In the NOR test, rats are exposed to two identical objects for 15 minutes in empty plastic box (60cmx60cmx30cm). After 3 hours, they are reintroduced to the same object and a new novel object for 10 minutes. This procedure was repeated for 4 days After completing the behavioral experiment, the ChAT of cholinergic neuron in the basal forebrain was ascertained to confirm with immunohistochemistry if cholinergic neuron was damaged. In NOR test, the lesion group with 192 IgG-saporin showed 10% lower novel object preference than normal group. However, this rate is not that significant value enough to elucidate behavioral difference between normal group and lesion group. In immunohistochemistry, the number of cholinergic neuron was remarkably decreased in basal forebrain. According to both of the NOR test and Immunohistochemistry in the condition under lesion, Cholingergic input to hippocampus and frontal cortex from basal forebrain affects recognition somewhat, however the effect is not so essential.

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

Clausen B, Klipec W, Bastlund J, Collins M (2011) P300-like event related potentials in IgG192-saporin induced rat model of Alzheimer´s disease. Neuroscience 2011 Abstracts 550.01. Society for Neuroscience, Washington, DC.

Summary: The P300 event-related potential (ERP) is a time-locked response to rare, response-relevant stimuli. Decreased ERP amplitude is correlated with decreased memory function. Not surprisingly, alterations in P300 ERP amplitude are commonly associated with the progressive disruption of cognitive function in human Alzheimer’s disease. Here, a rat model of Alzheimer’s disease was created by injecting the antibody-linked toxin, IgG192-saporin, into the basal forebrain, producing a progressive degeneration of cholinergic cells to mimic the cholinergic degeneration that is part of Alzheimer’s disease. The goal of this experiment was to investigate the rat model by examining the relationship between the expected degenerative deficits and possible changes in the EEG patterns. Following preliminary training that has produced reliable P300-like ERPs in prior experiments in our lab, half of the rats were injected with IgG192-saporin (lesioned), while the other half were injected with saline (controls). Recording electrodes were surgically implanted on the surface of the brain and in the prefrontal cortex (PFC) and ventral hippocampus (vHipp). Following recovery, P300-like ERP data was recorded for three weeks, after which a ChAT analysis of choline acetyltransferase activity confirmed the extent of cholinergic damage in PFC and Hipp. While no systematic increases in latency were found, surprisingly, significant increases in P300-like ERP amplitude occurred in PFC and vHipp in the lesioned compared to the control rats. The implication of these findings for a rat model of Alzheimer’s disease will be discussed.

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Winter SS, Köppen JR, Stout JM, Cameron HA, Wallace DG, Cheatwood JL (2011) Growth factor infusion increases BrdU-positive cells in the denervated medial septum following 192-IgG-saporin lesion. Neuroscience 2011 Abstracts 331.04. Society for Neuroscience, Washington, DC.

Summary: During the progression of Alzheimer’s Disease, degeneration of basal forebrain structures is associated with a decline in mnemonic function and frequently results in episodes of wandering behavior. Previous work has demonstrated that the septohippocampal cholinergic system uniquely contributes to rat spatial orientation. Enhancement of endogenous adult neurogenesis represents one potential method to restore function to the septohippocampal system. Therefore, we tested the hypothesis that co-infusion of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) would increase the number of new cells in the medial septum following a lesion of the cholinergic system produced by focal injection of the ribosome-inactivating selective immunotoxin 192-IgG-saporin in rats. For this, rats received injections of 192-IgG-saporin into the medial septum. At the same time, a cannula was placed in the lateral ventricle and attached to a subcutaneously-placed osmotic minipump containing either 1) EGF, bFGF, and bromodeoxyuridine (BrdU), or 2) BrdU alone. Infusion of growth factors and BrdU continued for a period of two weeks, at which point the pumps were removed. At 21 days following 192-IgG-saporin injury, rats were perfused following standard protocols. Cryostat sections were collected at 40 microns and were processed via double-fluorescent immunochemistry (IHC) using antibodies against BrdU and doublecortin (DCX). Photomicrographs of BrdU and DCX immunofluorescence were captured under epifluorescence and the number of BrdU-positive and DCX-positive cells was quantified. We detected significantly higher numbers of BrdU-positive cells in the medial septum of rats that received growth factors compared to rats that received BrdU-only (p<0.05). These results indicate that infusion of growth factors following 192-IgG-saporin lesion of the medial septum resulted in an increase in the number of new immature neurons in the medial septum. Studies aimed at determining the fate of these young neurons and their influences on spatial orientation are ongoing.

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Pacheco-Herrero M, Thyssen D, Ramos-Rodriguez J, Berrocoso E, Bacskai B, Garcia-Alloza M (2011) Rapid beta-amyloid deposition and behavioural impairment after cholinergic denervation in APPswe/PS1dE9. Neuroscience 2011 Abstracts 47.02. Society for Neuroscience, Washington, DC.

Summary: Alzheimer’s disease (AD) is the most common cause of dementia. Although the ultimate neurotoxic mechanisms are not known, extensive evidence supports the role of amyloid-beta (Aβ) deposition as senile plaques (SP) in the disease. On the other hand, neuronal loss is the pathological feature that best correlates with the duration and severity of the illness and specifically, cholinergic denervation of the basal forebrain seems to be a good predictor of clinical dementia in AD. A close relationship has been documented between Aβ deposition and neurodegeneration, however, whether specific neurodegeneration may lead to senile plaque deposition remains unclear. We addressed this by inducing selective cholinergic lesions in APPswe/PS1dE9 mice with murine p-75 saporin, an inmunotoxin that selectively removes cholinergic innervation. We performed intracerebroventricular murine p-75 lesions in animals with an incipient (~3 months) and robust (~7 months of age) Aβ deposition and removed ~50% of basal forebrain cholinergic innervation to cortex and hippocampus. Immediately after injections, cranial windows were implanted and Aβ deposition was monitored in vivo and in real time in the cortex using methoxy-XO4 and multiphoton microscopy. We observed increased SP deposition as soon as 1 week after the lesion. We further corroborated our in vivo data post-mortem, using anti- Aβ and anti-fibrils antibodies as well as thioflavin S staining, both in the cortex and the hippocampus. 7 days after the surgery, when the lesion is established, animals were tested in the new object discrimination and Morris water maze tests. We observed an early memory impairment in young lesioned mice (~3 months) and this effect worsened with age (~7 months of age), when Aβ deposition is more robust. Altogether, our data suggest that cholinergic denervation may contribute to the deposition of Aβ and synergistically contribute to the cognitive impairment observed in AD.

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

Croxson PL, Kyriazis DA, Baxter MG (2011) Cholinergic modulation of a specific memory function of prefrontal cortex. Nat Neurosci 14(12):1510-1512. doi: 10.1038/nn.2971

Summary: The authors investigated loss of acetylcholine in the large and highly differentiated PFC’s of rhesus monkeys. The monkeys received 80-92 20-ng injections of ME20.4-SAP (Cat. #IT-15) per hemisphere. Lesioned animals were severely impaired on tasks involving spatial working memory.

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Gelfo F, Tirassa P, De Bartolo P, Caltagirone C, Petrosini L, Angelucci F (2011) Brain and serum levels of nerve growth factor in a rat model of Alzheimer’s disease. J Alzheimers Dis 25(2):213-217. doi: 10.3233/JAD-2011-110047 PMID: 21368378

Objective: Using nerve growth factor (NGF) as a marker of disease progression in Alzheimer’s disease using cholinergic depletion animal models.

Summary: Different Alzheimer’s disease stages show different levels of NGF present in the brain. 192-IgG-SAP was used to deplete the cholinergic neurons in rats the same way as Alzheimer’s does in humans. NGF levels were measured by ELISA 3, 7, and 15 days after injection and a disease progression correlation with NGF was constructed.

Usage: 2 µL/side of immunotoxin 192 IgG-SAP (IT-01) diluted in PBS (2 µg/µL) was bilaterally injected into lateral ventricles (rate: 1 µL/min).

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Angelucci F, Gelfo F, De Bartolo P, Caltagirone C, Petrosini L (2011) BDNF concentrations are decreased in serum and parietal cortex in immunotoxin 192 IgG-Saporin rat model of cholinergic degeneration. Neurochem Int 59(1):1-4. doi: 10.1016/j.neuint.2011.04.010

Summary: Brain-derived neurotrophic factor (BDNF) plays a role in neuronal function during the degeneration of neurons caused by pathological conditions such as Alzheimer’s disease. In order to investigate the relationship between brain and serum BDNF levels the authors administered 2 µg of 192-IgG-SAP (Cat. #IT-01) into each lateral ventricle of rats and measured brain and serum BDNF levels by ELISA. It was found that BDNF levels dropped in lesioned animals, but not until 15 days post surgery.

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Antonini V, Marrazzo A, Kleiner G, Coradazzi M, Ronsisvalle S, Prezzavento O, Ronsisvalle G, Leanza G (2011) Anti-amnesic and neuroprotective actions of the sigma-1 receptor agonist (-)-MR22 in rats with selective cholinergic lesion and amyloid infusion. J Alzheimers Dis 24(3):569-586. doi: 10.3233/JAD-2011-101794 PMID: 21297260

Summary: Sigma-1 receptor agonists such as (-)-MR22 are potential therapeutic drugs for the treatment of cognitive and affective disorders. To model a cognitive disorder, rats received 81-ng bilateral injections of 192- IgG-SAP (Cat. #IT-01) into the medial septum/vertical limb of the diagonal band of Broca, and 130-ng bilateral injections into the nucleus basalis magnocellularis. Lesioned animals also were treated with pre- aggregated amyloid peptide. Pretreatment with (-)-MR22 reversed cognitive impairments in the double-lesioned animals, indicating the potential use of sigma-1 receptor agonists as protective agents.

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Koppen JR, Winter SS, Cheatwood JL, Wallace DG (2010) Role of the septohippocampal GABAergic system in spatial orientation. Neuroscience 2010 Abstracts 806.16/KKK21. Society for Neuroscience, San Diego, CA.

Summary: Spatial orientation depends on the integrity of multiple neural systems. For example, during the progression of Alzheimer’s Disease, degeneration of the basal forebrain is associated with cognitive impairments including episodes of wandering. The medial septum projects both cholinergic and GABAergic fibers into the hippocampus. Research and therapies have typically focused on enhancing function of the cholinergic component; however, the GABAergic component has also been shown to contribute to hippocampal function. Previous attempts to characterize the role of the GABAergic system in spatial orientation involved non-selective lesion techniques in combination with the water maze task have failed to characterize the nature of the deficit mediating the impaired performance. Development of GAT1-Saporin immunotoxin provides a novel tool to selectively destroy GABAergic neurons in the medial septum. The current study examined the effects of injecting GAT1-Saporin or saline (sham lesion) into the medial septum on spatial orientation using the food-hoarding paradigm. The food-hoarding paradigm involves training rats to search for food pellets on a large circular table and carrying the food pellet directly to a visible refuge. Three probes dissociate the use of environmental and self-movement cues: 1) Hidden probe involved placing the refuge below the surface of the table, limiting rats to use distal environmental or self-movement cues to locate the refuge; 2) Dark Probe involved using the hidden refuge with the room lights off, limiting rats to use self-movement cues to locate the refuge; 3) New probe involved placing the hidden refuge on the opposite side of table, placing environmental and self-movement cues in conflict. Both sham and GAT1-Saporin rats were accurate in returning to the refuge during the Hidden probe. Only sham rats were accurate in carrying food to the refuge during the Dark probe. During the New probe, both groups initially carried the food pellet to the former refuge location. Although sham rats consistently carried the food pellet to the new refuge location after their initial error, GAT1-Saporin rats continued to perseverate to the former refuge location. The current study demonstrates a role for the septohippocampal GABAergic system in spatial orientation related to processing self-movement cues.

Related Products: GAT1-SAP (Cat. #IT-32)