111Indium Labelling of Recombinant Activated Coagulation Factor VII : In Vitro and Preliminary In Vivo Studies in Healthy Rats

Abstract EN

The aim of this study is to investigate whether 111Indium-labelled recombinant FVIIa (rFVIIa) could be a potential radiopharmaceutical for localization of bleeding sources.

DTPA-conjugated rFVIIa was radiolabelled with 111In chloride.

In vitro binding efficiency of 111In-DTPA-rFVIIa to F1A2-Mab-sepharose was 99% in buffer, while it was 88–82% in serum.

The binding efficiency of 111In-DTPA-rFVIIa to TF (1–209)-sepharose was 48% in buffer whereas 39%–36% in serum, respectively.

In vivo experiment was conducted in healthy rats, and gamma camera images were taken immediately after iv.

administration of 1.6–1.8 MBq 111In-DTPA-rFVIIa up to 120–130 min.

Five min after administration of 111In-DTPA-rFVIIa, percentage of 111In activity was 6.0% in the cardiac region and 24.5% in the liver region.

After 2 hours activity was decreased to 3.3% in heart while it had increased to 42.0% in the liver.

The 111In-DTPA-rFVIIa might be a potential radiopharmaceutical for visualisation of tissues with significant TF expression such as acute bleeding lesions in the gastrointestinal tract.