- Email: [email protected]
S3-01-04: Prion vaccination
T150
Symposia S3-01: Other Dementias
have been tested in an attempt to find therapeutic agents, but only a few classes of compounds showed any beneficial effect in in vivo and/or in vitro models. Studies from our group led to recognize that tetracyclines are able to (i) revert the protease-resistance of the disease-associated prion protein isoforms extracted from brain tissue of patients with all forms of Creutzfeldt-Jakob disease (CJD) and cattle with BSE, (ii) reduce the infectivity titer in prion-contaminated material, and (iii) prolong survival of prion-infected animals. Methods: Twenty-one patients fulfilling the diagnostic criteria of probable CJD were authorized to receive compassionate treatment with doxycycline at a daily oral dose of 100 mg, from the time of diagnosis to death. Survival times were compared with those of 78 probable CJD patients who did not receive doxycycline treatment. Results: The prolonged treatment with doxycycline was well tolerated in all patients, without adverse secondary effects. The subjects treated with doxycycline (n⫽21) survived significantly longer than untreated patients (n⫽78); in particular, the survival time (median ⫾ SE) was 13.0 ⫾ 4.0 months in the former and 6.0 ⫾ 0.7 months in the latter (Log Rank test: p 0.001). A significant difference was still present when the doxycyclinetreated group was compared to an untreated group equivalent for sex, age at onset and codon 129 PRNP polymorphism (treated: 13.9 ⫾ 3.8 months, untreated: 6.1 ⫾ 0.5 months, p 0.01), which are major predictors of survival in CJD. Conclusions: The positive effects of doxycycline treatment on CJD survival seen in this observational study are currently under verification in a randomized, double-blind study of doxycycline versus placebo, approved by the Italian Agency of Drug. A positive outcome of this trial would activate similar studies in other neurodegenerative disorders due to protein misfolding such as Alzheimer’s disease, since the effects of doxycycline seem to be dependent upon a direct interaction with abnormal protein conformers having an extensive beta-sheet conformation rather than a specific amino acid sequence. S3-01-04
PRION VACCINATION
Thomas Wisniewski, NYU School of Medicine, New York, NY, USA. Contact e-mail: [email protected] Background: Significant outbreaks of prion disease linked to oral exposure of the prion agent have occurred in animal and human populations. These disorders are associated with a conformational change of a normal protein, PrPC, to a toxic and infectious form, PrPSc. None of the prionoses currently have an effective treatment. Some forms of prion disease are thought to be spread by oral ingestion of PrPSc, such as chronic wasting disease and variant Creutzfeldt-Jakob disease. Attempts to obtain an active immunization in wild-type animals have been hampered by auto-tolerance to PrP and potential toxicity. Previously, we demonstrated that it is possible to overcome tolerance and obtain a specific anti-PrP antibody response by oral inoculation of the PrP protein expressed in an attenuated Salmonella vector. This past study showed that 30% of vaccinated animals were free of disease more than 350 days post-challenge. Methods: We used an attenuated Salmonella vaccine strains that was made to express multiple repeats of the intact mouse PrP. Salmonella vaccine strains are a well characterized method to induce mucosal immunity. In addition to the oral immunization we boosted the immune response by adding ip immunizations with recombinant PrP. This proved to be a highly effective means of inducing high anti-PrP gut secretory IgA titers without apparent signs of toxicity. Results: Our immunization procedure proved to be a highly effective means of inducing high anti-PrP gut secretory IgA titers without apparent signs of toxicity. 100% of mice with a high mucosal anti-PrP titer IgA and a high systemic IgG titer, prior to challenge, remained without symptoms of PrP infection at 400 days (long-rank test p 0.0001 versus sham controls). The brains from these surviving clinically asymptomatic mice were free of PrPSc infection by Western blot and histological examination. Conclusions: These promising findings suggest that effective mucosal vaccination may be a useful method for overcoming tolerance to PrP and preventing prion infection via an oral route.
S3-01-05
MOLECULAR PATHOGENESIS OF FAMILIAL BRITISH DEMENTIA AND FAMILIAL DANISH DEMENTIA
Tamas Revesz, Institute of Neurology, University College London, London, United Kingdom. Contact e-mail: [email protected] Background: Two non-Abeta hereditary cerebral amyloid diseases, familial British dementia (FBD) and familial Danish dementia (FDD) have emerged as important alternative models of the neurodegenerative process resulting in dementia in Alzheimer’s disease (AD). The genetic abnormality in these diseases results in extension of the open reading frame generating disease-specific precursor proteins. The newly created C-terminal amyloidogenic peptide ABri in FBD and ADan in FDD form fibrils and deposit in cerebral pathological lesions. Methods: FBD and FDD as well as control brains were studied with morphological methods, including immunohistochemistry, immunoelectron microscopy, in situ hybridization, biochemical and proteomic approaches. Results: Our studies indicate that BRI2 mRNA and BRI2 protein are widely expressed by neurons and glia in human CNS. In FBD ABri deposits in amyloid plaques and in blood vessels (cerebral amyloid angiopathy - CAA), while in FDD the predominant parenchymal ADan deposits are of preamyloid (non-fibrillar) nature. In FDD co-localization of AbetaX-42 with ADan has been demonstrated in cerebrovascular amyloid. The neurofibrillary tangle pathology in FBD and FDD is immunohistochemically, ultrastructurally and biochemically indistinguishable from that seen in AD. Biochemical studies have demonstrated that ABri and ADan amyloid peptides are highly heterogeneous and posttranslationally modified. Amyloid-associated proteins are present in the parenchymal and vascular ABri and ADan lesions in a pattern similar to that seen in AD. In both diseases the parenchymal and vascular amyloid deposits are associated with a marked inflammatory response with activation of both the classical and the alternative complement pathways, suggesting that the chronic inflammatory response generated by the ABri and ADan amyloid peptides in vivo might contribute to the pathogenesis of FBD and FDD. Conclusions: Morphological features of both FBD and FDD closely mimic AD neuropathology despite the fact that the amyloid peptides ABri and ADan both differ from Abeta in length and primary structure. These observations emphasize the importance of amyloid proteins as a causative element in the process of neurodegeneration. The absence of compact plaques in the Danish kindred strongly indicates that compact amyloid plaques, which are fundamental lesions for the diagnosis of AD, are not a prerequisite for the neurodegenerative process. S3-01-06
CEREBRAL AMYLOID ANGIOPATHY: EPIDEMIOLOGY, CLINICAL FEATURES, AND GENETIC RISK FACTORS
Masahito Yamada, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan. Contact e-mail: [email protected] Background: Cerebral amyloid angiopathy (CAA) is classified to 6 subtypes according to the biochemical diversities of cerebrovascular amyloid proteins. Sporadic Abeta CAA is common in the elderly, especially in Alzheimer’s disease (AD). CAA is related to cerebrovascular disorders, particularly intracerebral hemorrhage (ICH), dementia, and vascular inflammation. Epidemiology of CAA-related ICH (CAA-ICH) has not been elucidated as yet. As a genetic risk factor, apolipoprotein E (ApoE) genotype was reported to be associated with CAA as well as AD. Methods: We performed a nationwide survey of CAA-ICH in Japan for last 5 years to clarify the epidemiology and clinical features. Further, to identify genetic risk factors for CAA, we investigated whether polymorphisms of genes related to Abeta metabolism or clearance were associated with CAA severity in 167 elderly subjects. Results: The nationwide study in Japan identified 794 patients with CAA-ICH, giving an estimate of 2,882 patients in the whole country and 7.49 per 100,000 people (age⫽55) as period prevalence. During the median duration of follow-up of 2.9 years, recurrence of ICH occurred in 31.7 %, and average duration to next recurrence
Symposia S3-01: Other Dementias
have been tested in an attempt to find therapeutic agents, but only a few classes of compounds showed any beneficial effect in in vivo and/or in vitro models. Studies from our group led to recognize that tetracyclines are able to (i) revert the protease-resistance of the disease-associated prion protein isoforms extracted from brain tissue of patients with all forms of Creutzfeldt-Jakob disease (CJD) and cattle with BSE, (ii) reduce the infectivity titer in prion-contaminated material, and (iii) prolong survival of prion-infected animals. Methods: Twenty-one patients fulfilling the diagnostic criteria of probable CJD were authorized to receive compassionate treatment with doxycycline at a daily oral dose of 100 mg, from the time of diagnosis to death. Survival times were compared with those of 78 probable CJD patients who did not receive doxycycline treatment. Results: The prolonged treatment with doxycycline was well tolerated in all patients, without adverse secondary effects. The subjects treated with doxycycline (n⫽21) survived significantly longer than untreated patients (n⫽78); in particular, the survival time (median ⫾ SE) was 13.0 ⫾ 4.0 months in the former and 6.0 ⫾ 0.7 months in the latter (Log Rank test: p 0.001). A significant difference was still present when the doxycyclinetreated group was compared to an untreated group equivalent for sex, age at onset and codon 129 PRNP polymorphism (treated: 13.9 ⫾ 3.8 months, untreated: 6.1 ⫾ 0.5 months, p 0.01), which are major predictors of survival in CJD. Conclusions: The positive effects of doxycycline treatment on CJD survival seen in this observational study are currently under verification in a randomized, double-blind study of doxycycline versus placebo, approved by the Italian Agency of Drug. A positive outcome of this trial would activate similar studies in other neurodegenerative disorders due to protein misfolding such as Alzheimer’s disease, since the effects of doxycycline seem to be dependent upon a direct interaction with abnormal protein conformers having an extensive beta-sheet conformation rather than a specific amino acid sequence. S3-01-04
PRION VACCINATION
Thomas Wisniewski, NYU School of Medicine, New York, NY, USA. Contact e-mail: [email protected] Background: Significant outbreaks of prion disease linked to oral exposure of the prion agent have occurred in animal and human populations. These disorders are associated with a conformational change of a normal protein, PrPC, to a toxic and infectious form, PrPSc. None of the prionoses currently have an effective treatment. Some forms of prion disease are thought to be spread by oral ingestion of PrPSc, such as chronic wasting disease and variant Creutzfeldt-Jakob disease. Attempts to obtain an active immunization in wild-type animals have been hampered by auto-tolerance to PrP and potential toxicity. Previously, we demonstrated that it is possible to overcome tolerance and obtain a specific anti-PrP antibody response by oral inoculation of the PrP protein expressed in an attenuated Salmonella vector. This past study showed that 30% of vaccinated animals were free of disease more than 350 days post-challenge. Methods: We used an attenuated Salmonella vaccine strains that was made to express multiple repeats of the intact mouse PrP. Salmonella vaccine strains are a well characterized method to induce mucosal immunity. In addition to the oral immunization we boosted the immune response by adding ip immunizations with recombinant PrP. This proved to be a highly effective means of inducing high anti-PrP gut secretory IgA titers without apparent signs of toxicity. Results: Our immunization procedure proved to be a highly effective means of inducing high anti-PrP gut secretory IgA titers without apparent signs of toxicity. 100% of mice with a high mucosal anti-PrP titer IgA and a high systemic IgG titer, prior to challenge, remained without symptoms of PrP infection at 400 days (long-rank test p 0.0001 versus sham controls). The brains from these surviving clinically asymptomatic mice were free of PrPSc infection by Western blot and histological examination. Conclusions: These promising findings suggest that effective mucosal vaccination may be a useful method for overcoming tolerance to PrP and preventing prion infection via an oral route.
S3-01-05
MOLECULAR PATHOGENESIS OF FAMILIAL BRITISH DEMENTIA AND FAMILIAL DANISH DEMENTIA
Tamas Revesz, Institute of Neurology, University College London, London, United Kingdom. Contact e-mail: [email protected] Background: Two non-Abeta hereditary cerebral amyloid diseases, familial British dementia (FBD) and familial Danish dementia (FDD) have emerged as important alternative models of the neurodegenerative process resulting in dementia in Alzheimer’s disease (AD). The genetic abnormality in these diseases results in extension of the open reading frame generating disease-specific precursor proteins. The newly created C-terminal amyloidogenic peptide ABri in FBD and ADan in FDD form fibrils and deposit in cerebral pathological lesions. Methods: FBD and FDD as well as control brains were studied with morphological methods, including immunohistochemistry, immunoelectron microscopy, in situ hybridization, biochemical and proteomic approaches. Results: Our studies indicate that BRI2 mRNA and BRI2 protein are widely expressed by neurons and glia in human CNS. In FBD ABri deposits in amyloid plaques and in blood vessels (cerebral amyloid angiopathy - CAA), while in FDD the predominant parenchymal ADan deposits are of preamyloid (non-fibrillar) nature. In FDD co-localization of AbetaX-42 with ADan has been demonstrated in cerebrovascular amyloid. The neurofibrillary tangle pathology in FBD and FDD is immunohistochemically, ultrastructurally and biochemically indistinguishable from that seen in AD. Biochemical studies have demonstrated that ABri and ADan amyloid peptides are highly heterogeneous and posttranslationally modified. Amyloid-associated proteins are present in the parenchymal and vascular ABri and ADan lesions in a pattern similar to that seen in AD. In both diseases the parenchymal and vascular amyloid deposits are associated with a marked inflammatory response with activation of both the classical and the alternative complement pathways, suggesting that the chronic inflammatory response generated by the ABri and ADan amyloid peptides in vivo might contribute to the pathogenesis of FBD and FDD. Conclusions: Morphological features of both FBD and FDD closely mimic AD neuropathology despite the fact that the amyloid peptides ABri and ADan both differ from Abeta in length and primary structure. These observations emphasize the importance of amyloid proteins as a causative element in the process of neurodegeneration. The absence of compact plaques in the Danish kindred strongly indicates that compact amyloid plaques, which are fundamental lesions for the diagnosis of AD, are not a prerequisite for the neurodegenerative process. S3-01-06
CEREBRAL AMYLOID ANGIOPATHY: EPIDEMIOLOGY, CLINICAL FEATURES, AND GENETIC RISK FACTORS
Masahito Yamada, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan. Contact e-mail: [email protected] Background: Cerebral amyloid angiopathy (CAA) is classified to 6 subtypes according to the biochemical diversities of cerebrovascular amyloid proteins. Sporadic Abeta CAA is common in the elderly, especially in Alzheimer’s disease (AD). CAA is related to cerebrovascular disorders, particularly intracerebral hemorrhage (ICH), dementia, and vascular inflammation. Epidemiology of CAA-related ICH (CAA-ICH) has not been elucidated as yet. As a genetic risk factor, apolipoprotein E (ApoE) genotype was reported to be associated with CAA as well as AD. Methods: We performed a nationwide survey of CAA-ICH in Japan for last 5 years to clarify the epidemiology and clinical features. Further, to identify genetic risk factors for CAA, we investigated whether polymorphisms of genes related to Abeta metabolism or clearance were associated with CAA severity in 167 elderly subjects. Results: The nationwide study in Japan identified 794 patients with CAA-ICH, giving an estimate of 2,882 patients in the whole country and 7.49 per 100,000 people (age⫽55) as period prevalence. During the median duration of follow-up of 2.9 years, recurrence of ICH occurred in 31.7 %, and average duration to next recurrence