Related Experiment Video
Updated: May 28, 2026
Biochemical Purification and Proteomic Characterization of Amyloid Fibril Cores from the Brain
Published on: April 28, 2022
Comparative analysis of peptide p5 and serum amyloid P component for imaging AA amyloid in mice using dual-isotope
Jonathan S Wall1, Tina Richey, Angela Williams
1Department of Radiology, University of Tennessee Graduate School of Medicine, Knoxville, TN 37920-6999, USA. jwall@utmck.edu
Purpose:
I-labeled human serum amyloid P component (SAP) is used clinically only in the UK for imaging visceral amyloidosis to assist with diagnosis, disease staging, and monitoring response to therapy. We compare a new amyloid-reactive probe, peptide p5, with SAP for imaging amyloidosis.
Procedures:
Dual-energy SPECT/CT images were acquired of (125)I-labeled SAP and (99m)Tc-labeled p5 in mice with systemic AA amyloidosis (n = 3). Twelve organs and tissues were harvested for radiotracer biodistribution assessment and for micro-autoradiographic analysis.
Results:
I-SAP and (99m)Tc-p5 localized equivalently in amyloid deposits in liver (∼10% injected dose (ID)/g) whereas (125)I-SAP was twofold higher in the spleen (∼20% ID/g; (99m)Tc-p5, ∼10% ID/g). In contrast, (99m)Tc-p5 was bound to pancreatic and intestinal amyloid approximately fivefold more efficiently as evidenced in biodistribution data.
Conclusions:
Radiolabeled p5 is an effective amyloid-imaging radiotracer as compared to SAP in the murine model of amyloidosis and may be rapidly translated for imaging patients with visceral amyloidosis in the USA.
