Biodistribution of the fatty acid analogue 18F-FTHA: plasma and tissue partitioning between lipid pools during fasting and hyperinsulinemia
: Guiducci L, Grönroos T, Järvisalo MJ, Kiss J, Viljanen A, Naum AG, Viljanen T, Savunen T, Knuuti J, Ferrannini E, Salvadori PA, Nuutila P, Iozzo P
Publisher: Society of Nuclear Medicine and Molecular Imaging
: 2007
: 48
: 3
: 455
: 462
DOI: https://doi.org/NA(external)
Alterations of free
fatty acid (FA) metabolism in several organs are implicated in the
pathogenesis of chronic disorders. The aim of this study was to
investigate the biodistribution and partitioning of the FA analog,
14(R,S)-(18)F-fluoro-6-thia-heptadecanoic acid ((18)F-FTHA), across
different lipid pools in plasma and in metabolically important organs
and its response to insulin.
Eight
anesthetized pigs were studied during fasting or euglycemic insulin
stimulation. Plasma samples from the carotid artery, hepatic vein, and
portal vein were collected at 10 and 40 min after (18)F-FTHA injection
via indwelling catheters. The animals were then sacrificed and tissue
biopsies rapidly obtained from the heart, brain, liver, subcutaneous and
visceral fat, pancreas, intestine, and skeletal muscle. Radioactivity
was assessed in the FA, phospholipid, and triglyceride or glycerol ester
pools.
The
tissue-to-plasma intact (18)F-FTHA ratio was high in all tissues, with
the highest values being in the heart and liver; (18)F-FTHA accumulated
in the brain to a significant extent. Hyperinsulinemia was associated
with higher plasma (18)F-FTHA clearance (P < 0.05) and lower labeled
triglyceride appearance (P
(18)F-FTHA
is a promising tracer in PET imaging of metabolically important organs,
which are currently inaccessible in vivo. Physiologic hyperinsulinemia
enhances plasma tracer clearance in fat, skeletal muscle, and pancreas.
