- Email: [email protected]
In vitro characterization of s44858: A positive allosteric modulator of ampa receptors and GluN2B selective non-competitive nmda receptors antagonist
P612
Poster Presentations: P2
AD features were replicated in human apoE4 target replacement mice (in contrast to human apoE3 replacement mice) thus providing a pharmacological model for assessing therapeutic modalities in apoE4 AD. Results: In a lead selection two ABCA1 agonist with favorable brain penetration were compared for their efficacy assessing AD phenotype characteristics in the hippocampus showing superior effects by CogpepB. CogpepB doseresponse was assessed by administering 20 and 60mg/kg/48 hour for 6 weeks assessing Novel Object Recognition, NOR). A highly statistically significant improvement in NOR compared to placebo was found by the lower dose with no additional benefit by the higher dose. In a 3rdstudy 20mg/kg/48h CogpepB was administered for 6 weeks to apoE4 and apoE3 mice and compared to placebo assessing Morris water maze test derived cognition which showed highly significant improvement in the apoE4 active group to that of the apoE3 mice. Interestingly, CogpepB treatment had no effect on apoE3 mice suggesting that the treatment effect is limited to apoE4 mice, potentially by correction of apoE4’s conformational restrictions with regard to ABCA1 interaction and lipid transfer from cells to extra-cellular apoE4. This mechanism of action notion was supported by direct demonstration of increased apoE4 lipidation by CogpepB. Conclusions: Taken together the findings suggest that an ABCA1 agonist, CogpepB, designed from the lipid binding segment of apoE is able to correct the apoE4 lipidation insufficiency thereby normalizing apoE4 phenotype and cognition. CogpepB therefore represents a novel therapeutic approach to apoE4 AD.
P2-310
IMPROVING SYNAPTIC PLASTICITY AND COGNITIVE FUNCTION IN RODENTS BY THE NOVEL PHOSPHODIESTERASE 9A INHIBITOR BI 409306
Holger Rosenbrock1, Anelise Marti1, Eliza Koros1, Frank Runge1, Holger Fuchs1, Riccardo Giovannini2, Cornelia Dorner-Ciossek1, 1 Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany; 2 Boehringer Ingelheim Research Italia, Milano, Italy. Contact e-mail: [email protected] Background: Phosphodiesterases (PDEs) in the brain have shown to
play an important role in synaptic plasticity and cognitive function. Among those PDEs is PDE9A, which specifically regulates the second messenger cGMP in neurons related to NMDA receptor signaling and is expressed in cognition relevant regions of the brain. Thus, PDE9A inhibitors are hypothesized to improve cognitive function via increasing NMDA receptor related cGMP signalling pathway to strengthen synaptic plasticity. This study characterizes the effects of the novel PDE9A inhibitor BI 409306 on hippocampal long-term potentiation (LTP), a widely accepted cellular experimental model of synaptic plasticity and memory formation. Moreover, the drug was evaluated for cGMP increase in rat cerebrospinal fluid (CSF) and brain and for improving memory function. Methods: The molecular potency of BI 409306 for PDE9A was determined using cytosolic extracts of SF9 insect cells over-expressing full-length human enzyme employing SPA technology. Functional effects of BI 409306 regarding synaptic plasticity were tested on LTP in rat hippocampal slices using a high-frequency stimulation paradigm for LTP induction in CA1 region. cGMP levels in rat prefrontal cortex were determined by using microdialysis technique and microdialysis probes were measured using a cGMP-specific radio-immunoassay. cGMP levels in rat CSF samples were determined by HPLC-MS/MS technique. Effects on
cognition were assessed in a novel object recognition task in mice. Results: The IC50 value of BI 409306 on PDE9A was determined
to be 52 nM. BI 409306 application to rat hippocampal slices significantly increased hippocampal LTP and induced a dosedependent increase of cGMP in rat CSF and prefrontal cortex. Regarding cognition, BI 409306 improved memory performance in the object recognition task which addresses episodic memory function. Conclusions: The study shows that BI 409306 is a potent PDE9A inhibitor which strengthens synaptic plasticity as demonstrated by increased hippocampal LTP. Systemic application of BI 409306 to rats increased cGMP levels in the CSF and brain indicating functional target engagement. Corroborating previous reports on memory enhancing efficacy of other PDE9A inhibitors in rodents, this data further demonstrates that PDE9A inhibition may be a potential approach to pharmacologically improve cognition in CNS disorders.
P2-311
IN VITRO CHARACTERIZATION OF S44858: A POSITIVE ALLOSTERIC MODULATOR OF AMPA RECEPTORS AND GLUN2B SELECTIVE NON-COMPETITIVE NMDA RECEPTORS ANTAGONIST
Laurence Danober1, Jean-Yves Thomas1, Sylvie Challal1, Nathalie Rogez1, Karine Albinet1, Nadege Villain1, Laetitia Mony2, Pierre Paoletti2, Daniel Bertrand3, Stephanie Wagner4, Patrice Desos5, Alex Cordi5, Pierre Lestage1, 1P^ole Innovation Therapeutique Neuropsychiatrie, Institut de Recherches Servier, Croissy-sur-Seine, France; 2Institut de Biologie de l’Ecole Normale Superieure, CNRS-INSERM, Paris, France; 3HiQScreen, Vesenaz Geneva, Switzerland; 4 Neurofit, Illkirch, France; 5P^ole Expertise Recherche et Biopharmacie, Institut de Recherches Servier, Suresnes, France. Contact e-mail: Laurence. [email protected] Background: Modulation of the glutamate receptors has become
prime targets for improving cognition in Alzheimer, schizophrenia and depression. S44858 presents a unique mechanism of action, as it both potentiates AMPA receptors and blocks NMDA receptors. The aim of the present work was to characterize its mechanism of action using different in vitro approaches. Methods: Binding to the glutamate, ifenprodil, PCP or glycine sites on AMPA, kainate and NMDA receptors was determined on rat brain membrane preparation. Mechanism of action was examined using two-electrodes voltage-clamp recordings conducted in Xenopus laevis oocytes injected with either rat cortex or human hippocampal mRNAs or with rodent or human GluN1/GluN2A-2B-2C-2D cDNAs. Neuroprotective activity was evaluated by measuring the LDH activity on rat cortical cultures. Expression of Brain-Derived Neurotrophic Factor (BDNF) protein was measured by ELISA on primary rat cortical cultures. Extracellular AMPA and NMDA-mediated postsynaptic responses were recorded on Wistar rat hippocampal slices. Results: S44858 does not present affinity towards glutamate binding sites on AMPA, kainate and NMDA receptors nor towards glycine and PCP binding sites. A low affinity for the ifenprodil binding site is detected. On oocytes injected with rat cortex or human hippocampal mRNA, S44858 increases AMPA responses, but does not affect kainate responses and decreases NMDA responses. Differential sensitivity of S44858 was uncovered at the human AMPA receptors subtypes. S44858 displays also selectivity towards GluN2B subunits compared to other GluN2 subunits on rodent and human NMDA receptors. S44858 presents no toxicity on rat
Poster Presentations: P2
primary cultures but protects them from glutamate and NMDA insults. S44858 also increases AMPA-mediated BDNF expression. Finally, S44858 increases both AMPA-mediated synaptic responses and long-term potentiation, while decreasing NMDAmediated synaptic responses. Conclusions: Taken together, these results revealed that S44858 is a potent positive modulator of AMPA receptors and GluN2B selective antagonist. S44858 presents in vitro neurotrophic and neuroprotective properties and enhances synaptic plasticity. Further in vivo evaluations confirm that S44858 possesses neuroprotective, cognitive enhancing and antidepressant properties administration in the absence of side effects in rodents. Altogether, S44858 represents an attractive drug candidate for the treatment of various CNS diseases in which dysfunctions of glutamatergic pathways have been implicated.
kg i.p. in mice. S44858 also displays neuroprotective activity in middle cerebral artery occlusion (10-30 mg/kg i.p.) in mice and increases the sucrose drinking in the chronic mild stress model of depression (0.3-1 mg/kg p.o.) in rats. No effect on general behaviour, body temperature and spontaneous locomotor activity or occurrence of epileptic seizures was noticed after acute administration in mice and rats (10-100 mg/kg p.o.). Conclusions: Taken together, these results indicate that S44858 is neuroprotective, enhances cognition and synaptic plasticity and is antidepressant in the absence of side effects in rodents. S44858 is therefore an attractive drug candidate for the treatment of various CNS diseases in which dysfunctions of glutamatergic pathways have been implicated.
P2-313 P2-312
IN VIVO CHARACTERIZATION OF S44858, A POSITIVE ALLOSTERIC MODULATOR OF AMPA RECEPTORS AND GLUN2B SELECTIVE NON-COMPETITIVE NMDA ANTAGONIST
Pierre Lestage1, Laurence Danober1, Jean-Yves Thomas1, Martine Krentner1, Anita Roger1, Karine Albinet1, Caroline Louis1, Valerie Bertaina-Anglade2, Ali Kazem3, Daniel Beracochea3, Regis Bordet4, Mariusz Papp5, Celine Junges6, Marc Bertrand6, Patrice Desos7, Alex Cordi7, 1P^ole Innovation Therapeutique Neuropsychiatrie, Institut de Recherches Servier, Croissy-sur-Seine, France; 2Briotrial, Rennes, France; 3Universite de Bordeaux, Bordeaux, France; 4Service de Pharmacologie-H^opital Huriez-CHRU, Lille, France; 5 Institut of Pharmacology, Polish Academic of Sciences, Krakow, Poland; 6 P^ ole Expertise Recherche et Biopharmacie, Technologie Servier, Orleans, ole Expertise Recherche et Biopharmacie, Institut de Recherches France; 7P^ Servier, Suresnes, France. Contact e-mail: [email protected] Background: S45858 is a novel positive allosteric modulator of AMPA-type receptors that blocks GluN2B subtypes of NMDA receptors. S44858 protects against excitototoxicity, enhances BDNF expression and synaptic plasticity in vitro. The aim of the present work was to characterize in vivo pharmacological properties and safety of S44858. Methods: Plasmatic and cerebral concentrations were determined after acute oral administration. Extracellular excitatory postsynaptic responses were recorded in the dendritic field of the dentate gyrus of the hippocampus. Cognition was tested in natural forgetting in either Novel Object Recognition task or in spontaneous alternation task in T-maze. Effect of S44858 on aged-induced memory deficits was examined in Contextual Serial Discriminations task in a four-hole board apparatus after 9 d administration. Neuroprotection was evaluated on middle cerebral artery occlusion. Antidepressant-like effect was investigated in a chronic mild stress model of depression after 1-5 weeks administration. Changes in autonomic function, locomotor activity and body temperature were recorded in rodents. Results: Permeability of the BloodBrain-Barrier of S44848 is high in rats and mice. S44858 (30 mg/kg i.p.) both increases the synaptic response and the LTP in the hippocampal dentate gyrus on anesthetized rats. S44858 improves episodic-like memory in a novel object recognition test at 0.3-1 mg/kg p.o. in rats and mice and is able to reverse ageinduced deficits in contextual memory performances at 0.1-0.3 mg/kg/d p.o. in mice. S44858 improves spatial working memory in the spontaneous alternation test on a T-maze at 0.03-0.3 mg/
P613
INTRANASAL DEFEROXAMINE PREVENTS MEMORY LOSS IN THE INTRACEREBROVENTRICULAR STREPTOZOTOCIN RAT MODEL OF ALZHEIMER’S DISEASE
Jared M. Fine1, Anna C. Forsberg1, Benjamin M. Stroebel1, Dylan R. Verden1, Katherine A. Hamel1, Elise B. Raney1, William H. Frey, II,1, Leah R. Hanson2, 1HealthPartners Institute for Education and Research, St. Paul, MN, USA; 2HealthPartners Center for Memory and Aging, St. Paul, MN, USA. Contact e-mail: jared.m.fine@healthpartners. com Background: Deferoxamine (DFO) is a metal chelator found to
decrease cognitive decline in a clinical trial of Alzheimer’s patients. However, this trial included painful intramuscular injections and side-effects such as nausea. Recent pre-clinical studies have shown that when delivered intranasally (IN), DFO decreased memory loss as measured by water maze in the APP/PS1 (amyloid) and P301L (tau) mouse models of Alzheimer’s disease. In this study the intracerebroventricular streptozotocin (ICV STZ) rat model, which includes both inflammation and insulin dysregulation, was treated with IN DFO. Methods: Treatment groups included Sprague Dawley rats with ICV injections of either STZ or saline (sham), which were treated intranasally with either saline or DFO (n¼10-15/ group). The five treatment groups were 1) Sham+IN saline, 2) STZ+IN saline, 3) Sham+IN DFO, 4) STZ+IN DFO (both pre and post-surgical treatment), and 5) STZ+IN DFO (post-surgical treatment only). Pre-treatment with IN saline or DFO began 4 days prior to model induction, which entailed ICV injection of STZ using a stereotaxic device. IN treatment continued 3x/wk for 3 weeks before behavior tests started and eventual euthanasia with tissue collection. Results: Spatial memory tests with the Morris water maze demonstrated a clear effect of the model, in which ICV STZ rats had significantly longer escape latencies (p<0.05) using a mixed-effects Cox-proportional hazards model. The same analyses showed that both groups of STZ rats treated with IN DFO had significantly shorter escape latencies than their saline-treated controls (p<0.05). These results were seen with both the fixed platform and moving platform water mazes. Pre-treatment with IN DFO also significantly decreased footslips on the tapered balance beam test (p<0.05). Conclusions: Intranasal DFO decreased the spatial memory loss associated with the ICV STZ rat model of sporadic Alzheimer’s disease. Furthermore, the pre-treatment decreased
Poster Presentations: P2
AD features were replicated in human apoE4 target replacement mice (in contrast to human apoE3 replacement mice) thus providing a pharmacological model for assessing therapeutic modalities in apoE4 AD. Results: In a lead selection two ABCA1 agonist with favorable brain penetration were compared for their efficacy assessing AD phenotype characteristics in the hippocampus showing superior effects by CogpepB. CogpepB doseresponse was assessed by administering 20 and 60mg/kg/48 hour for 6 weeks assessing Novel Object Recognition, NOR). A highly statistically significant improvement in NOR compared to placebo was found by the lower dose with no additional benefit by the higher dose. In a 3rdstudy 20mg/kg/48h CogpepB was administered for 6 weeks to apoE4 and apoE3 mice and compared to placebo assessing Morris water maze test derived cognition which showed highly significant improvement in the apoE4 active group to that of the apoE3 mice. Interestingly, CogpepB treatment had no effect on apoE3 mice suggesting that the treatment effect is limited to apoE4 mice, potentially by correction of apoE4’s conformational restrictions with regard to ABCA1 interaction and lipid transfer from cells to extra-cellular apoE4. This mechanism of action notion was supported by direct demonstration of increased apoE4 lipidation by CogpepB. Conclusions: Taken together the findings suggest that an ABCA1 agonist, CogpepB, designed from the lipid binding segment of apoE is able to correct the apoE4 lipidation insufficiency thereby normalizing apoE4 phenotype and cognition. CogpepB therefore represents a novel therapeutic approach to apoE4 AD.
P2-310
IMPROVING SYNAPTIC PLASTICITY AND COGNITIVE FUNCTION IN RODENTS BY THE NOVEL PHOSPHODIESTERASE 9A INHIBITOR BI 409306
Holger Rosenbrock1, Anelise Marti1, Eliza Koros1, Frank Runge1, Holger Fuchs1, Riccardo Giovannini2, Cornelia Dorner-Ciossek1, 1 Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany; 2 Boehringer Ingelheim Research Italia, Milano, Italy. Contact e-mail: [email protected] Background: Phosphodiesterases (PDEs) in the brain have shown to
play an important role in synaptic plasticity and cognitive function. Among those PDEs is PDE9A, which specifically regulates the second messenger cGMP in neurons related to NMDA receptor signaling and is expressed in cognition relevant regions of the brain. Thus, PDE9A inhibitors are hypothesized to improve cognitive function via increasing NMDA receptor related cGMP signalling pathway to strengthen synaptic plasticity. This study characterizes the effects of the novel PDE9A inhibitor BI 409306 on hippocampal long-term potentiation (LTP), a widely accepted cellular experimental model of synaptic plasticity and memory formation. Moreover, the drug was evaluated for cGMP increase in rat cerebrospinal fluid (CSF) and brain and for improving memory function. Methods: The molecular potency of BI 409306 for PDE9A was determined using cytosolic extracts of SF9 insect cells over-expressing full-length human enzyme employing SPA technology. Functional effects of BI 409306 regarding synaptic plasticity were tested on LTP in rat hippocampal slices using a high-frequency stimulation paradigm for LTP induction in CA1 region. cGMP levels in rat prefrontal cortex were determined by using microdialysis technique and microdialysis probes were measured using a cGMP-specific radio-immunoassay. cGMP levels in rat CSF samples were determined by HPLC-MS/MS technique. Effects on
cognition were assessed in a novel object recognition task in mice. Results: The IC50 value of BI 409306 on PDE9A was determined
to be 52 nM. BI 409306 application to rat hippocampal slices significantly increased hippocampal LTP and induced a dosedependent increase of cGMP in rat CSF and prefrontal cortex. Regarding cognition, BI 409306 improved memory performance in the object recognition task which addresses episodic memory function. Conclusions: The study shows that BI 409306 is a potent PDE9A inhibitor which strengthens synaptic plasticity as demonstrated by increased hippocampal LTP. Systemic application of BI 409306 to rats increased cGMP levels in the CSF and brain indicating functional target engagement. Corroborating previous reports on memory enhancing efficacy of other PDE9A inhibitors in rodents, this data further demonstrates that PDE9A inhibition may be a potential approach to pharmacologically improve cognition in CNS disorders.
P2-311
IN VITRO CHARACTERIZATION OF S44858: A POSITIVE ALLOSTERIC MODULATOR OF AMPA RECEPTORS AND GLUN2B SELECTIVE NON-COMPETITIVE NMDA RECEPTORS ANTAGONIST
Laurence Danober1, Jean-Yves Thomas1, Sylvie Challal1, Nathalie Rogez1, Karine Albinet1, Nadege Villain1, Laetitia Mony2, Pierre Paoletti2, Daniel Bertrand3, Stephanie Wagner4, Patrice Desos5, Alex Cordi5, Pierre Lestage1, 1P^ole Innovation Therapeutique Neuropsychiatrie, Institut de Recherches Servier, Croissy-sur-Seine, France; 2Institut de Biologie de l’Ecole Normale Superieure, CNRS-INSERM, Paris, France; 3HiQScreen, Vesenaz Geneva, Switzerland; 4 Neurofit, Illkirch, France; 5P^ole Expertise Recherche et Biopharmacie, Institut de Recherches Servier, Suresnes, France. Contact e-mail: Laurence. [email protected] Background: Modulation of the glutamate receptors has become
prime targets for improving cognition in Alzheimer, schizophrenia and depression. S44858 presents a unique mechanism of action, as it both potentiates AMPA receptors and blocks NMDA receptors. The aim of the present work was to characterize its mechanism of action using different in vitro approaches. Methods: Binding to the glutamate, ifenprodil, PCP or glycine sites on AMPA, kainate and NMDA receptors was determined on rat brain membrane preparation. Mechanism of action was examined using two-electrodes voltage-clamp recordings conducted in Xenopus laevis oocytes injected with either rat cortex or human hippocampal mRNAs or with rodent or human GluN1/GluN2A-2B-2C-2D cDNAs. Neuroprotective activity was evaluated by measuring the LDH activity on rat cortical cultures. Expression of Brain-Derived Neurotrophic Factor (BDNF) protein was measured by ELISA on primary rat cortical cultures. Extracellular AMPA and NMDA-mediated postsynaptic responses were recorded on Wistar rat hippocampal slices. Results: S44858 does not present affinity towards glutamate binding sites on AMPA, kainate and NMDA receptors nor towards glycine and PCP binding sites. A low affinity for the ifenprodil binding site is detected. On oocytes injected with rat cortex or human hippocampal mRNA, S44858 increases AMPA responses, but does not affect kainate responses and decreases NMDA responses. Differential sensitivity of S44858 was uncovered at the human AMPA receptors subtypes. S44858 displays also selectivity towards GluN2B subunits compared to other GluN2 subunits on rodent and human NMDA receptors. S44858 presents no toxicity on rat
Poster Presentations: P2
primary cultures but protects them from glutamate and NMDA insults. S44858 also increases AMPA-mediated BDNF expression. Finally, S44858 increases both AMPA-mediated synaptic responses and long-term potentiation, while decreasing NMDAmediated synaptic responses. Conclusions: Taken together, these results revealed that S44858 is a potent positive modulator of AMPA receptors and GluN2B selective antagonist. S44858 presents in vitro neurotrophic and neuroprotective properties and enhances synaptic plasticity. Further in vivo evaluations confirm that S44858 possesses neuroprotective, cognitive enhancing and antidepressant properties administration in the absence of side effects in rodents. Altogether, S44858 represents an attractive drug candidate for the treatment of various CNS diseases in which dysfunctions of glutamatergic pathways have been implicated.
kg i.p. in mice. S44858 also displays neuroprotective activity in middle cerebral artery occlusion (10-30 mg/kg i.p.) in mice and increases the sucrose drinking in the chronic mild stress model of depression (0.3-1 mg/kg p.o.) in rats. No effect on general behaviour, body temperature and spontaneous locomotor activity or occurrence of epileptic seizures was noticed after acute administration in mice and rats (10-100 mg/kg p.o.). Conclusions: Taken together, these results indicate that S44858 is neuroprotective, enhances cognition and synaptic plasticity and is antidepressant in the absence of side effects in rodents. S44858 is therefore an attractive drug candidate for the treatment of various CNS diseases in which dysfunctions of glutamatergic pathways have been implicated.
P2-313 P2-312
IN VIVO CHARACTERIZATION OF S44858, A POSITIVE ALLOSTERIC MODULATOR OF AMPA RECEPTORS AND GLUN2B SELECTIVE NON-COMPETITIVE NMDA ANTAGONIST
Pierre Lestage1, Laurence Danober1, Jean-Yves Thomas1, Martine Krentner1, Anita Roger1, Karine Albinet1, Caroline Louis1, Valerie Bertaina-Anglade2, Ali Kazem3, Daniel Beracochea3, Regis Bordet4, Mariusz Papp5, Celine Junges6, Marc Bertrand6, Patrice Desos7, Alex Cordi7, 1P^ole Innovation Therapeutique Neuropsychiatrie, Institut de Recherches Servier, Croissy-sur-Seine, France; 2Briotrial, Rennes, France; 3Universite de Bordeaux, Bordeaux, France; 4Service de Pharmacologie-H^opital Huriez-CHRU, Lille, France; 5 Institut of Pharmacology, Polish Academic of Sciences, Krakow, Poland; 6 P^ ole Expertise Recherche et Biopharmacie, Technologie Servier, Orleans, ole Expertise Recherche et Biopharmacie, Institut de Recherches France; 7P^ Servier, Suresnes, France. Contact e-mail: [email protected] Background: S45858 is a novel positive allosteric modulator of AMPA-type receptors that blocks GluN2B subtypes of NMDA receptors. S44858 protects against excitototoxicity, enhances BDNF expression and synaptic plasticity in vitro. The aim of the present work was to characterize in vivo pharmacological properties and safety of S44858. Methods: Plasmatic and cerebral concentrations were determined after acute oral administration. Extracellular excitatory postsynaptic responses were recorded in the dendritic field of the dentate gyrus of the hippocampus. Cognition was tested in natural forgetting in either Novel Object Recognition task or in spontaneous alternation task in T-maze. Effect of S44858 on aged-induced memory deficits was examined in Contextual Serial Discriminations task in a four-hole board apparatus after 9 d administration. Neuroprotection was evaluated on middle cerebral artery occlusion. Antidepressant-like effect was investigated in a chronic mild stress model of depression after 1-5 weeks administration. Changes in autonomic function, locomotor activity and body temperature were recorded in rodents. Results: Permeability of the BloodBrain-Barrier of S44848 is high in rats and mice. S44858 (30 mg/kg i.p.) both increases the synaptic response and the LTP in the hippocampal dentate gyrus on anesthetized rats. S44858 improves episodic-like memory in a novel object recognition test at 0.3-1 mg/kg p.o. in rats and mice and is able to reverse ageinduced deficits in contextual memory performances at 0.1-0.3 mg/kg/d p.o. in mice. S44858 improves spatial working memory in the spontaneous alternation test on a T-maze at 0.03-0.3 mg/
P613
INTRANASAL DEFEROXAMINE PREVENTS MEMORY LOSS IN THE INTRACEREBROVENTRICULAR STREPTOZOTOCIN RAT MODEL OF ALZHEIMER’S DISEASE
Jared M. Fine1, Anna C. Forsberg1, Benjamin M. Stroebel1, Dylan R. Verden1, Katherine A. Hamel1, Elise B. Raney1, William H. Frey, II,1, Leah R. Hanson2, 1HealthPartners Institute for Education and Research, St. Paul, MN, USA; 2HealthPartners Center for Memory and Aging, St. Paul, MN, USA. Contact e-mail: jared.m.fine@healthpartners. com Background: Deferoxamine (DFO) is a metal chelator found to
decrease cognitive decline in a clinical trial of Alzheimer’s patients. However, this trial included painful intramuscular injections and side-effects such as nausea. Recent pre-clinical studies have shown that when delivered intranasally (IN), DFO decreased memory loss as measured by water maze in the APP/PS1 (amyloid) and P301L (tau) mouse models of Alzheimer’s disease. In this study the intracerebroventricular streptozotocin (ICV STZ) rat model, which includes both inflammation and insulin dysregulation, was treated with IN DFO. Methods: Treatment groups included Sprague Dawley rats with ICV injections of either STZ or saline (sham), which were treated intranasally with either saline or DFO (n¼10-15/ group). The five treatment groups were 1) Sham+IN saline, 2) STZ+IN saline, 3) Sham+IN DFO, 4) STZ+IN DFO (both pre and post-surgical treatment), and 5) STZ+IN DFO (post-surgical treatment only). Pre-treatment with IN saline or DFO began 4 days prior to model induction, which entailed ICV injection of STZ using a stereotaxic device. IN treatment continued 3x/wk for 3 weeks before behavior tests started and eventual euthanasia with tissue collection. Results: Spatial memory tests with the Morris water maze demonstrated a clear effect of the model, in which ICV STZ rats had significantly longer escape latencies (p<0.05) using a mixed-effects Cox-proportional hazards model. The same analyses showed that both groups of STZ rats treated with IN DFO had significantly shorter escape latencies than their saline-treated controls (p<0.05). These results were seen with both the fixed platform and moving platform water mazes. Pre-treatment with IN DFO also significantly decreased footslips on the tapered balance beam test (p<0.05). Conclusions: Intranasal DFO decreased the spatial memory loss associated with the ICV STZ rat model of sporadic Alzheimer’s disease. Furthermore, the pre-treatment decreased