Comparative analysis of peptide p5 and serum amyloid P component for imaging AA amyloid in mice using dual-isotope SPECT.

ABSTRACT: 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.

SUBMITTER: Wall JS 

PROVIDER: S-EPMC3664664 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature