Pharmacological removal of serum amyloid P component from intracerebral plaques and cerebrovascular Aβ amyloid deposits in vivo.

Abstract

Human amyloid deposits always contain the normal plasma protein serum amyloid P component (SAP), owing to its avid but reversible binding to all amyloid fibrils, including the amyloid β (Aβ) fibrils in the cerebral parenchyma plaques and cerebrovascular amyloid deposits of Alzheimer's disease (AD) and cerebral amyloid angiopathy (CAA). SAP promotes amyloid fibril formation in vitro, contributes to persistence of amyloid in vivo and is also itself directly toxic to cerebral neurons. We therefore developed (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC), a drug that removes SAP from the blood, and thereby also from the cerebrospinal fluid (CSF), in patients with AD. Here we report that, after introduction of transgenic human SAP expression in the TASTPM double transgenic mouse model of AD, all the amyloid deposits contained human SAP. Depletion of circulating human SAP by CPHPC administration in these mice removed all detectable human SAP from both the intracerebral and cerebrovascular amyloid. The demonstration that removal of SAP from the blood and CSF also removes it from these amyloid deposits crucially validates the strategy of the forthcoming 'Depletion of serum amyloid P component in Alzheimer's disease (DESPIAD)' clinical trial of CPHPC. The results also strongly support clinical testing of CPHPC in patients with CAA.

• Authors: Raya Al-Shawi, Glenys A Tennent, David J Millar, Angela Richard-Londt, Sebastian Brandner, David J Werring, J Paul Simons, Mark B Pepys
• Journal: Open biology (Open Biol) Vol. 6 Issue 2 Pg. 150202 (Feb 2016) ISSN: 2046-2441 [Electronic] England
• PMID: 26842068 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2016 The Authors.

Chemical References

• Amyloid beta-Peptides
• Serum Amyloid P-Component

Topics

• Alzheimer Disease (metabolism, pathology)
• Amyloid beta-Peptides (metabolism)
• Animals
• Cerebral Amyloid Angiopathy (metabolism, pathology)
• Disease Models, Animal
• Humans
• Immunohistochemistry
• Mice
• Mice, Transgenic
• Plaque, Amyloid (metabolism)
• Protein Aggregation, Pathological (drug therapy, metabolism)
• Serum Amyloid P-Component (genetics, metabolism)