Fluorescence image-guided surgery combined with intraoperative therapeutic modalities has great potential for intraoperative detection of oncologic targets and eradication of unresectable cancer residues. Therefore, we have developed an activatable theranostic nanoplatform that can be used concurrently for two purposes: (1) tumor delineation with real-time near infrared (NIR) fluorescence signal during surgery, and (2) intraoperative targeted treatment to further eliminate unresected disease sites by non-toxic phototherapy.

Circulating cancer exosomes are microvesicles which originate from malignant cells and other organs influenced by the disease and can be found in blood. The exosomal proteomic cargo can often be traced to the cells from which they originated, reflecting the physiological status of these cells. The similarities between cancer exosomes and the tumor cells they originate from exhibit the potential of these vesicles as an invaluable target for liquid biopsies. Exosomes were isolated from the serum of eight osteosarcoma-bearing dogs, five healthy dogs, and five dogs with traumatic fractures. We also characterized exosomes which were collected longitudinally from patients with osteosarcoma prior and 2 weeks after amputation, and eventually upon detection of lung metastasis. Exosomal proteins fraction were analyzed by label-free mass spectrometry proteomics and were validated with immunoblots of selected proteins. Ten exosomal proteins were found that collectively discriminate serum of osteosarcoma patients from serum healthy or fractured dogs with an accuracy of 85%. Additionally, serum from different disease stages could be distinguished with an accuracy of 77% based on exosomal proteomic composition. The most discriminating protein changes for both sample group comparisons were related to complement regulation, suggesting an immune evasion mechanism in early stages of osteosarcoma as well as in advanced disease.

OBJECTIVE To evaluate the usefulness of injection of indocyanine green (ICG) solution with near-infrared (NIR) fluorescence imaging for transcutaneous detection of sentinel lymph nodes (SLNs) and their associated lymphatic vessels in the oral mucosa of healthy dogs. ANIMALS 6 adult purpose-bred research hounds. PROCEDURES Each dog was sedated, and 1 mL of ICG solution was injected into the gingival mucosa dorsal to the right maxillary canine tooth. Subsequently, NIR fluorescence imaging was used to transcutaneously detect the lymphatic vessels and SLNs. The distance between the injection site and each SLN was measured. Time to first evidence of node fluorescence was recorded, and velocity of ICG movement was calculated. A slide preparation of a fine-needle aspiration sample of the fluorescing structure underwent cytologic examination (to confirm presence of lymphatic tissue) and NIR fluorescence imaging (to confirm presence of ICG). RESULTS The ipsilateral mandibular lymphocentrum was the SLN in all dogs. The time to visually detectable fluorescence ranged from 4 to 15 minutes (mean ± SD, 8.8 ± 3.76 minutes). The mean velocity was 1.94 ± 0.93 cm/min. Fluorescence was not observed in the contralateral lymph nodes. Each fluorescing structure was confirmed to be lymphatic tissue, and NIR fluorescence imaging revealed that ICG was present in the sampled SLN. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that injection of ICG solution with NIR fluorescence imaging can be used to transcutaneously identify SLNs along with associated lymphatic vessels in the oral mucosa of healthy dogs. Time from injection to identification of fluorescence was rapid with prolonged retention of material within the SLN, indicating that this procedure could be performed during surgery.