Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy

The plaques associated with Alzheimer’s disease are formed as a result of the aggregation of Aβ peptides, which vary in length from 38 to 43 amino acids. The 1-40 peptide is the most abundant, while the 1-42 peptide appears to be the most destructive to neurons and/or glial cells in a variety of ass...

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Main Authors: Allen P. Kaplan, Berhane Ghebrehiwet, Kusumam Joseph
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/13/24/2039
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author Allen P. Kaplan
Berhane Ghebrehiwet
Kusumam Joseph
author_facet Allen P. Kaplan
Berhane Ghebrehiwet
Kusumam Joseph
author_sort Allen P. Kaplan
collection DOAJ
description The plaques associated with Alzheimer’s disease are formed as a result of the aggregation of Aβ peptides, which vary in length from 38 to 43 amino acids. The 1-40 peptide is the most abundant, while the 1-42 peptide appears to be the most destructive to neurons and/or glial cells in a variety of assays. We have demonstrated that aggregated Aβ, a state prior to plaque formation, will activate the plasma bradykinin-forming pathway when tested in vitro. Aggregation is zinc-dependent, optimal at 25–50 µM, and the rate of aggregation is paralleled by the rate of activation of the bradykinin-forming pathway as assessed by plasma kallikrein formation. The aggregation of Aβ 1-38, 1-40, and 1-42 is optimal after incubation for 3 days, 3 h, and under 1 min, respectively. The cascade is initiated by the autoactivation of factor XII upon binding to aggregated Aβ; then, prekallikrein is converted to kallikrein, which cleaves high-molecular-weight kininogen (HK) to release bradykinin. Studies by a variety of other researchers have demonstrated the presence of each “activation-step” in either the plasma or spinal fluid of patients with Alzheimer’s disease, including activated factor XII, kallikrein, and bradykinin itself. There is also evidence that activation is more prominent as dementia worsens. We now have medications that can block each step of the bradykinin-forming pathway as currently employed for the therapy of hereditary angioedema. Given the current state of therapy for Alzheimer’s disease, which includes monoclonal antibodies that retard the rate of progression by 30% at most and have significant side effects, it seems imperative to explore prophylaxis using one of the long-acting agents that target plasma kallikrein or factor XIIa. There is a long-acting bradykinin antagonist in development, and techniques to target kallikrein mRNA to lower levels or knock out the prekallikrein gene are being developed.
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spelling doaj-art-72e4b6b005524487a74cddd17a471bfa2025-08-20T02:55:56ZengMDPI AGCells2073-44092024-12-011324203910.3390/cells13242039Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for TherapyAllen P. Kaplan0Berhane Ghebrehiwet1Kusumam Joseph2Department of Medicine, The Medical University of South Carolina, Charleston, SC 29425, USADepartment of Medicine, Stony Brook University, Stony Brook, NY 11794, USAAstria Pharmaceuticals, Boston, MA 02210, USAThe plaques associated with Alzheimer’s disease are formed as a result of the aggregation of Aβ peptides, which vary in length from 38 to 43 amino acids. The 1-40 peptide is the most abundant, while the 1-42 peptide appears to be the most destructive to neurons and/or glial cells in a variety of assays. We have demonstrated that aggregated Aβ, a state prior to plaque formation, will activate the plasma bradykinin-forming pathway when tested in vitro. Aggregation is zinc-dependent, optimal at 25–50 µM, and the rate of aggregation is paralleled by the rate of activation of the bradykinin-forming pathway as assessed by plasma kallikrein formation. The aggregation of Aβ 1-38, 1-40, and 1-42 is optimal after incubation for 3 days, 3 h, and under 1 min, respectively. The cascade is initiated by the autoactivation of factor XII upon binding to aggregated Aβ; then, prekallikrein is converted to kallikrein, which cleaves high-molecular-weight kininogen (HK) to release bradykinin. Studies by a variety of other researchers have demonstrated the presence of each “activation-step” in either the plasma or spinal fluid of patients with Alzheimer’s disease, including activated factor XII, kallikrein, and bradykinin itself. There is also evidence that activation is more prominent as dementia worsens. We now have medications that can block each step of the bradykinin-forming pathway as currently employed for the therapy of hereditary angioedema. Given the current state of therapy for Alzheimer’s disease, which includes monoclonal antibodies that retard the rate of progression by 30% at most and have significant side effects, it seems imperative to explore prophylaxis using one of the long-acting agents that target plasma kallikrein or factor XIIa. There is a long-acting bradykinin antagonist in development, and techniques to target kallikrein mRNA to lower levels or knock out the prekallikrein gene are being developed.https://www.mdpi.com/2073-4409/13/24/2039Alzheimer’sbradykininkallikrein
spellingShingle Allen P. Kaplan
Berhane Ghebrehiwet
Kusumam Joseph
Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
Cells
Alzheimer’s
bradykinin
kallikrein
title Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
title_full Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
title_fullStr Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
title_full_unstemmed Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
title_short Alzheimer’s Disease: In Vitro and In Vivo Evidence of Activation of the Plasma Bradykinin-Forming Cascade and Implications for Therapy
title_sort alzheimer s disease in vitro and in vivo evidence of activation of the plasma bradykinin forming cascade and implications for therapy
topic Alzheimer’s
bradykinin
kallikrein
url https://www.mdpi.com/2073-4409/13/24/2039
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