A simple and effective diagnostic test for gastrointestinal bleeding to improve patient outcomes

DESCRIPTION provided by applicant Problem Lower gastrointestinal bleeding is a significant medical problem in the United States accounting for more than hospital admissions and tens of billions of dollars of healthcare spending annually It is common for bleeding from a single site to stop and restart multiple times The three modalities now used to diagnose and locate gastrointestinal bleeding fail of the time largely because they all require a minimum rate of bleeding at the time of the test Without locating the source the patient continues to be at risk for further bleeding Approach Our initial proof of principle in ivo studies illustrate that a radiolabeled fibrinogen based molecular imaging tracer will concentrate at the injured blood vessel wall as part of the adherent clot and the tracer can be used to locate
bleeding sites even after bleeding has stopped To advance the fibrinogen based tracer concept towards a clinical test we propose to leverage single photon emission computed tomography and develop a tracer consisting of fibrinogen labeled with technetium m We propose to develop and test a high efficiency protocol to produce biologically active mTc fibrinogen An iterative set of experiments would maximize yield and specific activity of the radiolabeling process while maintaining stability and biological activity of the tracer Using the optimized process to produce an injectable SPECT tracer we would next demonstrate the efficacy of mTc fibrinogen to detect bleeding in an animal model Bleeding at a biopsy site in the descending colon of a rat will be located using SPECT imaging the results will be confirmed by radiometric measurements of excised tissues Impact The proposed technology represents a shift in the clinical paradigm for detecting lower gastrointestinal bleeding because it locates injured blood vessels not bleeding itself Our ultimate clinical product would consist of a radiopharmaceutical preparatory kit for preparing a single patient dose of the SPECT tracer using a mTc generator The tracer will be administered intravenously and localized using a nuclear medicine camera The mTc generator and camera are standard equipment in most hospitals Primary use will be for accurate diagnosis of lower gastrointestinal bleeding and possibly bleeding due to other disorders A rapid and accurate test to locate bleeding sites would transform the standard care measured as lower cost of healthcare due to fewer test procedures and associated complications shorter in patient days and reduced morbidity and mortality in patient outcomes

PUBLIC HEALTH RELEVANCE Bleeding in the lower gastrointestinal tract typically stops and starts again and is surprisingly difficult to locate since available tests fail of the time to locate the bleeding source The answer why is that current tests are only effective if the patient is bleeding during testing We are developing a faster safer test that locates the clot formed at the bleeding site rather than bleeding per se enabling accurate diagnosis of gastrointestinal bleeding and improved outcomes for patients with this diagnosis