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Biomarkers across other neurodegenerative diseases as Parkinson's disease (PD)
Featured Research Session Abstract Submission F5-04: Neuroinflammation-Related Phenomenons in Alzheimer’s Disease 3) a submission package to support qualification by the EMA and FDA. Conclusions: Overview of these new processes, regulatory interactions, types of data required, analysis plans, potential questions to be addressed, potential pitfalls, and some examples of the utility of these type of drug development tools for trial simulation activities in mild to moderate AD. F5-03-05
REGULATORY CONSIDERATIONS
Maria Isaac, European Medicines Agency, London United Kingdom. Background: Early detection of the disease would be especially important to provide opportunity for early intervention to reduce disease progression or even reverse disease course. A number of pharmaceutical companies are developing novel agents that may be able to alter the trajectory of disease. Certain biomarkers, such as volumetric magnetic resonance imaging (MRI) or CSF amyloid and tau, which can be evidenced as having usefulness for trial design. Methods: EMA, FDA and other authorities have suggested a process for the review of novel methodologies, with updates on submissions of AD biomarkers and models for progression. There had earlier been a successful process with safety biomarkers. Results: The European Medicines Agency has released the first qualification opinion for a clinical biomarker for public consultation. The biomarker is intended to identify patients who can be recruited for clinical trials of treatments for pre-dementia Alzheimer’s disease. Conclusions: A process is now established with a focus on acceptability of specific use of the proposed biomarkers developed for a specific intended use in the context of pharmaceutical R&D. F5-03-06
BIOMARKERS ACROSS OTHER NEURODEGENERATIVE DISEASES AS PARKINSON’S DISEASE (PD)
Louis Kirby, Coalition Against Major Diseases, Tucson, Ariz., United States. Background: Early stage diagnosis is important for mechanism-based treatments in AD and PD. Biomarkers are going through the process of regulatory approval for use in the enrollment of subjects with episodic memory amnestic patients with MCI, similarly in PD for patient with fewer motor symptoms than full diagnosis. Methods: Identification of PD rests on distinguishing it from the other conditions exhibiting Parkinson’s-like symptoms. SPECT DAT analysis is unable to distinguish PD from most of the degenerative parkinsonisms that manifest a loss of DAT. For that separation, clinical means are employed. Results: Assessing Clinical criteria to diagnose PD across sites and the timing of the diagnosis with respect to the clinical diagnosis, the sensitivity ranged from 73% to 99% but the specificity ranged from 8% to 86%. SPECT visualization is approved as a device assist in the evaluation of adult patients with suspected Parkinsonian syndromes PS for DAT deficiency but not idiopathic Parkinson’s disease. Conclusions: Review of data from controlled follow up studies reveal the increased sensitivity and specificity of early stage enrollment for clinical PD trials using SPECT DAT scanning as a biomarker for which a qualification is being sought. THURSDAY, JULY 21, 2011 FEATURED RESEARCH SESSION ABSTRACT SUBMISSION F5-04 NEUROINFLAMMATION-RELATED PHENOMENONS IN ALZHEIMER’S DISEASE F5-04-01
A ROLE FOR HYPERTENSION IN CAA, NEUROINFLAMMATION AND NEUROPATHOLOGY IN ALZHEIMER’S?
David Cribbs, University of California, Irvine, Irvine, Calif., United States. Background: The common co-occurrence of Alzheimer’s disease (AD) and cerebral vascular pathology mesh with epidemiologic data showing that
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many vascular risk factors are also risk factors for brain atrophy and dementia. Currently, there is increasing recognition that cerebral vascular dysfunction plays a critical role in many neurodegenerative diseases, including AD where approximately 80-95% of the cases have cerebrovascular pathology. Furthermore, age-related cerebrovascular dysfunction contributes to ischemic stroke, intracerebral hemorrhages, and microbleeds. Apart from age, the greatest risk factor for cerebrovascular dysfunction is hypertension, and hypertension in midlife has been reported to increase the risk of dementia in the elderly. Hypertension commonly causes cerebral small vessel disease (SVD) in the white matter, which increases the risk of stroke and dementia. Surprisingly, plasma amyloid-beta1-40 (Ab40) levels have recently been independently associated with the diffuse-SVD subtype, and these results are consistent with the pathophysiological role of Ab40 in disrupting vascular endothelial function. Finally, the accumulation of Ab40 in the cerebrovascular system is a significant risk factor for intracerebral hemorrhage (ICH), and may also play a role in endothelial transport failure and blockage of perivascular drainage that may attenuate clearance of CNS waste products from the brain. Currently, there are no animal studies demonstrating a direct involvement of hypertension in the accumulation of Alzheimer’s disease-like pathology. To address this issue we have developed several mouse models that combine hypertension protocols with amyloid precursor protein (APP) transgenic mice (Tg2576), which accumulate significant CAA in the large cerebral vessels and the meninges by 18 months of age. Methods: All experiments were carried out in accordance with the Institutional Animal Care and Use Committee at the University of California, Irvine, and were consistent with Federal guidelines. To induce hypertension in the mouse models, we used 3 different protocols for chronic administration of angiotensin II by subcutaneously implanted Alzet mini-osmotic pumps. First we used chronic angiotensin II alone at a dose of 1.1 mg/Kg/ day for 28 days in 12 months old Tg2576 or non-Tg littermates. Control groups received PBS by subcutaneously implanted Alzet mini-osmotic pumps. The second protocol utilized angiotensin II at the same dose but with the addition of L-NAME (100 mg/Kg/day), an inhibitor of nitric oxide synthase, in 24-month old mice. In the third protocol we supplemented the second chronic protocol (angiotensin II + L-NAME) after one week with acute angiotensin II injections (0.5 ug/g) twice daily in 14-months old mice because acute increases in blood pressure may contribute to rupture of cerebral blood vessels. Blood pressure was measured daily in conscious mice using a Kent Scientific non-invasive tail-cuff blood pressure monitor system. Clinical signs of stroke were measured using contralateral forelimb extension, circling behavior and other tests for motor dysfunction. Mice were overdosed with 100 mg/kg of Nembutal and intracardially perfused with 25 ml of ice cold PBS, pH 7.2. Brains were rapidly removed and were bisected along the mid-sagittal plane. One half was fixed in 4% paraformaldehyde for 24 hours for immunohistochemical analysis and the other half was snap-frozen on dry ice and pulverized for biochemical analysis. Brain sections were immunostained for total Ab, Ab40 and Ab42 and ELISAs for Ab40 and Ab42 were also performed. Prussian blue staining for hemosiderin deposits was used for microhemorrhage detection and the sections were counterstained with nuclear fast red. Results: Chronic angiotensin II only administration to 12 months old mice for 28 days did not induce clinical signs of stroke in non-Tg littermates or Tg2576 mice, even though mean blood pressure values rose to greater than 150 mmHg by the end of the experiment in both groups of mice. However, both non-Tg and Tg2576 mice displayed increased neuroinflammation in response to the hypertensive condition as observed by activated phenotypes for microglia and astrocytes when compared to the PBS control mice. Hypertensive Tg2576 mice developed more CAA and a trend toward greater plaque load than PBS-treated Tg2576 mice. Finally, there was a significant increase in cerebral Ab by ELISA for the hypertensive Tg2576 mice relative to the PBS group. We next tested the more aggressive chronic plus acute hypertension model in 14 months old Tg2576 mice. Within 5 days Tg2576 mice began to show clinical symptoms of stroke, whereas clinical symptoms were delayed by more than 5 days in non-Tg mice. The mean blood pressure values rose to greater than 160 mmHg at 14 days. Due to loss of mice we ended the
REGULATORY CONSIDERATIONS
Maria Isaac, European Medicines Agency, London United Kingdom. Background: Early detection of the disease would be especially important to provide opportunity for early intervention to reduce disease progression or even reverse disease course. A number of pharmaceutical companies are developing novel agents that may be able to alter the trajectory of disease. Certain biomarkers, such as volumetric magnetic resonance imaging (MRI) or CSF amyloid and tau, which can be evidenced as having usefulness for trial design. Methods: EMA, FDA and other authorities have suggested a process for the review of novel methodologies, with updates on submissions of AD biomarkers and models for progression. There had earlier been a successful process with safety biomarkers. Results: The European Medicines Agency has released the first qualification opinion for a clinical biomarker for public consultation. The biomarker is intended to identify patients who can be recruited for clinical trials of treatments for pre-dementia Alzheimer’s disease. Conclusions: A process is now established with a focus on acceptability of specific use of the proposed biomarkers developed for a specific intended use in the context of pharmaceutical R&D. F5-03-06
BIOMARKERS ACROSS OTHER NEURODEGENERATIVE DISEASES AS PARKINSON’S DISEASE (PD)
Louis Kirby, Coalition Against Major Diseases, Tucson, Ariz., United States. Background: Early stage diagnosis is important for mechanism-based treatments in AD and PD. Biomarkers are going through the process of regulatory approval for use in the enrollment of subjects with episodic memory amnestic patients with MCI, similarly in PD for patient with fewer motor symptoms than full diagnosis. Methods: Identification of PD rests on distinguishing it from the other conditions exhibiting Parkinson’s-like symptoms. SPECT DAT analysis is unable to distinguish PD from most of the degenerative parkinsonisms that manifest a loss of DAT. For that separation, clinical means are employed. Results: Assessing Clinical criteria to diagnose PD across sites and the timing of the diagnosis with respect to the clinical diagnosis, the sensitivity ranged from 73% to 99% but the specificity ranged from 8% to 86%. SPECT visualization is approved as a device assist in the evaluation of adult patients with suspected Parkinsonian syndromes PS for DAT deficiency but not idiopathic Parkinson’s disease. Conclusions: Review of data from controlled follow up studies reveal the increased sensitivity and specificity of early stage enrollment for clinical PD trials using SPECT DAT scanning as a biomarker for which a qualification is being sought. THURSDAY, JULY 21, 2011 FEATURED RESEARCH SESSION ABSTRACT SUBMISSION F5-04 NEUROINFLAMMATION-RELATED PHENOMENONS IN ALZHEIMER’S DISEASE F5-04-01
A ROLE FOR HYPERTENSION IN CAA, NEUROINFLAMMATION AND NEUROPATHOLOGY IN ALZHEIMER’S?
David Cribbs, University of California, Irvine, Irvine, Calif., United States. Background: The common co-occurrence of Alzheimer’s disease (AD) and cerebral vascular pathology mesh with epidemiologic data showing that
S811
many vascular risk factors are also risk factors for brain atrophy and dementia. Currently, there is increasing recognition that cerebral vascular dysfunction plays a critical role in many neurodegenerative diseases, including AD where approximately 80-95% of the cases have cerebrovascular pathology. Furthermore, age-related cerebrovascular dysfunction contributes to ischemic stroke, intracerebral hemorrhages, and microbleeds. Apart from age, the greatest risk factor for cerebrovascular dysfunction is hypertension, and hypertension in midlife has been reported to increase the risk of dementia in the elderly. Hypertension commonly causes cerebral small vessel disease (SVD) in the white matter, which increases the risk of stroke and dementia. Surprisingly, plasma amyloid-beta1-40 (Ab40) levels have recently been independently associated with the diffuse-SVD subtype, and these results are consistent with the pathophysiological role of Ab40 in disrupting vascular endothelial function. Finally, the accumulation of Ab40 in the cerebrovascular system is a significant risk factor for intracerebral hemorrhage (ICH), and may also play a role in endothelial transport failure and blockage of perivascular drainage that may attenuate clearance of CNS waste products from the brain. Currently, there are no animal studies demonstrating a direct involvement of hypertension in the accumulation of Alzheimer’s disease-like pathology. To address this issue we have developed several mouse models that combine hypertension protocols with amyloid precursor protein (APP) transgenic mice (Tg2576), which accumulate significant CAA in the large cerebral vessels and the meninges by 18 months of age. Methods: All experiments were carried out in accordance with the Institutional Animal Care and Use Committee at the University of California, Irvine, and were consistent with Federal guidelines. To induce hypertension in the mouse models, we used 3 different protocols for chronic administration of angiotensin II by subcutaneously implanted Alzet mini-osmotic pumps. First we used chronic angiotensin II alone at a dose of 1.1 mg/Kg/ day for 28 days in 12 months old Tg2576 or non-Tg littermates. Control groups received PBS by subcutaneously implanted Alzet mini-osmotic pumps. The second protocol utilized angiotensin II at the same dose but with the addition of L-NAME (100 mg/Kg/day), an inhibitor of nitric oxide synthase, in 24-month old mice. In the third protocol we supplemented the second chronic protocol (angiotensin II + L-NAME) after one week with acute angiotensin II injections (0.5 ug/g) twice daily in 14-months old mice because acute increases in blood pressure may contribute to rupture of cerebral blood vessels. Blood pressure was measured daily in conscious mice using a Kent Scientific non-invasive tail-cuff blood pressure monitor system. Clinical signs of stroke were measured using contralateral forelimb extension, circling behavior and other tests for motor dysfunction. Mice were overdosed with 100 mg/kg of Nembutal and intracardially perfused with 25 ml of ice cold PBS, pH 7.2. Brains were rapidly removed and were bisected along the mid-sagittal plane. One half was fixed in 4% paraformaldehyde for 24 hours for immunohistochemical analysis and the other half was snap-frozen on dry ice and pulverized for biochemical analysis. Brain sections were immunostained for total Ab, Ab40 and Ab42 and ELISAs for Ab40 and Ab42 were also performed. Prussian blue staining for hemosiderin deposits was used for microhemorrhage detection and the sections were counterstained with nuclear fast red. Results: Chronic angiotensin II only administration to 12 months old mice for 28 days did not induce clinical signs of stroke in non-Tg littermates or Tg2576 mice, even though mean blood pressure values rose to greater than 150 mmHg by the end of the experiment in both groups of mice. However, both non-Tg and Tg2576 mice displayed increased neuroinflammation in response to the hypertensive condition as observed by activated phenotypes for microglia and astrocytes when compared to the PBS control mice. Hypertensive Tg2576 mice developed more CAA and a trend toward greater plaque load than PBS-treated Tg2576 mice. Finally, there was a significant increase in cerebral Ab by ELISA for the hypertensive Tg2576 mice relative to the PBS group. We next tested the more aggressive chronic plus acute hypertension model in 14 months old Tg2576 mice. Within 5 days Tg2576 mice began to show clinical symptoms of stroke, whereas clinical symptoms were delayed by more than 5 days in non-Tg mice. The mean blood pressure values rose to greater than 160 mmHg at 14 days. Due to loss of mice we ended the