68Ga-BNOTA-PRGD2 PET/CT in Evaluation of Angiogenesis Following Stroke

Integrin αvβ3 is an important member of this receptor family and expressed preferentially on regenerative vascular endothelial cells, but not or very low on the quiescent vessel cells and other normal cells. The αvβ3 integrin is a key mediator of angiogenesis and thus may be an important diagnostic and therapeutic target associated with cerebrovascular repair processes after stroke.

The tri-peptide sequence of arginine-glycine-aspartic acid (RGD) can specifically bind to the integrin αvβ3 receptor. Accordingly, a variety of radiolabeled RGD-based peptides have been developed for non-invasive imaging of integrin αvβ3 expression via positron emission tomography (PET) or single photon emission computed tomography (SPECT) to monitor the angiogenesis in clinical Oncology and Cardiology. In Neurology, angiogenesis imaging based on integrin αvβ3 receptor has not been found in clinical trials, but preclinical animal studies showed it had great potential for clinical translation. Recently, series of RGD dimeric peptides with PEG linkers have been studied. The new types of RGD peptides showed much higher in vitro integrin αvβ3 binding affinity than the single RGD tri-peptide sequence. As a representative, 68Ga-BNOTA-PRGD2 could be easily prepared and exhibited excellent in vivo behavior in animal models and also tumor or myocardial infarction patients. No adverse reactions are observed in animal models or patients to date.

For the further interests in clinical translation of 68Ga-BNOTA-PRGD2, an open-label brain PET/CT study was designed to investigate diagnostic performance of 68Ga-BNOTA-PRGD2 in stroke patients in convalescence. A single dose of nearly 111 MBq 68Ga-BNOTA-PRGD2 ( ≤ 40 µg BNOTA-PRGD2) will be intravenously injected into the patients. Visual and semiquantitative method will be used to assess the PET/CT images. Changes of brain 18F-FDG PET/CT, enhanced brain MRI or CT, and any adverse events will be collected from the patients.