PET Quantification of Beta Cells in Baboons Using a Novel Imaging Agent

A unique marker on the surface of the human beta cell (called VMAT2) holds promise as a noninvasive imaging target to allow measurement of the number of beta cells a person possesses. However, finding imaging agents that bind specifically to this marker in human beta cells has been challenging. This study used baboons, which are a better model for humans than rodents, to test the value of a new imaging agent for the beta cell marker, as well as understand how to build more specific agents against the human beta cell marker. The new imaging agent showed specific binding in the pancreas of the baboons, suggesting utility in humans. Further studies appear warranted to directly estimate pancreatic binding in humans including T1D patients and also to clarify the cause of the apparent overestimation of beta cell numbers in T1D from previous animal studies.

Ramifications for Individuals with T1D:

A tool to accurately and noninvasively measure the amount of beta cells a person has would be useful in the development of new therapeutics as well as clinical trials on all stages of T1D. Such a tool could more quickly indicate if a new therapy was halting beta cell loss or stimulating their regrowth and expansion. This could speed the development of new therapies to cure T1D.

JDRF Involvement:

JDRF did not support this study.

Investigators and Institutions:

Harris PE, Farwell MD, Ichise M. Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY.

Reference:

Harris PE, Farwell MD, Ichise M. (2013) PET quantification of pancreatic VMAT 2 binding using (+) and (-) enantiomers of [(18)F]FP-DTBZ in baboons. Nucl Med Biol. 40(1):60-4 [Epub ahead of print 2012 Oct 26].