Identification of a pancreatic juice-specific fluorescent probe through 411 probes activated by aminopeptidases/proteases or phosphatases/phosphodiesterases

Abstract

Background

This study is a retrospective review aimed to identify pancreatic juice-specific fluorescent probes to visualize pancreatic juice using a library of 381 aminopeptidase/protease-activatable fluorescent probes and 30 phosphatase/phosphodiesterase probes. In 2013, we developed a fluorescence imaging technique using a chymotrypsin probe to visualize pancreatic juice, linked to postoperative pancreatic fistula (POPF). This probe required addition of trypsin to convert pancreatic chymotrypsinogen to chymotrypsin. Recently we accessed libraries of enzyme-activatable fluorescent probes to find probes that facilitated target-specific imaging.

Methods

Pancreatic juice and ascitic fluid samples were collected in eight patients undergoing pancreaticoduodenectomy. Reaction rates of pancreatic juice to background ascitic fluids were calculated for these 411 fluorescent probes.

Results

Forty-four fluorescent probes were screened in terms of high reactivity with pancreatic juice. Only one candidate probe targeting ectonucleotide pyrophosphatase/phosphodiesterase (ENPP) 1 was selected for a pancreatic juice-specific fluorescent probe. Inhibitor experiments and Western blotting supported the presence of ENPP1 in the pancreatic juice.

Conclusion

ENPP1-targeting fluorescent probe may have the potential to visualize pancreatic juice leakage during surgery. This finding may allow surgeons to suture leaking sites and decide the necessity of prophylactic abdominal drains; however, the role of ENPP1 in pancreatic juice remains to be clarified.