Selecting Potential Targetable Biomarkers for Imaging Purposes in Colorectal Cancer Using TArget Selection Criteria (TASC):A Novel Target Identification Tool

Peritoneal carcinomatosis (PC) of colorectal origin is associated with a poor prognosis. However, cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is available for a selected group of PC patients, which significantly increases overall survival rates up to 30%. As a consequence, there is substantial room for improvement. Tumor targeting is expected to improve the treatment efficacy of colorectal cancer (CRC) further through 1) more sensitive preoperative tumor detection, thus reducing overtreatment; 2) better intraoperative detection and surgical elimination of residual disease using tumor-specific intraoperative imaging; and 3) tumor-specific targeted therapeutics. This review focuses, in particular, on the development of tumor-targeted imaging agents. A large number of biomarkers are known to be upregulated in CRC. However, to date, no validated criteria have been described for the selection of the most promising biomarkers for tumor targeting. Such a scoring system might improve the selection of the correct biomarker for imaging purposes. In this review, we present the TArget Selection Criteria (TASC) scoring system for selection of potential biomarkers for tumor-targeted imaging. By applying TASC to biomarkers for CRC, we identified seven biomarkers (carcinoembryonic antigen, CXC chemokine receptor 4, epidermal growth factor receptor, epithelial cell adhesion molecule, matrix metalloproteinases, mucin 1, and vascular endothelial growth factor A) that seem most suitable for tumor-targeted imaging applications in colorectal cancer. Further cross-validation studies in CRC and other tumor types are necessary to establish its definitive value

Preclinical studies and prospective clinical applications for bacteria-targeted imaging:the future is bright

Bacterial infections are a frequently occurring and major complication in human healthcare, in particular due to the rapid increase of antimicrobial resistance and the emergence of pan-drug-resistant microbes. Current anatomical and functional imaging modalities are insufficiently capable of distinguishing sites of bacterial infection from sterile inflammation. Therefore, definitive diagnosis of an infection can often only be obtained by tissue biopsy and subsequent culture and, occasionally, a definite diagnosis even appears to be impossible. To accurately diagnose bacterial infections early, novel imaging modalities are urgently needed. In this regard, bacteria-targeted imaging is an attractive option due to its specificity. Here, different bacteria-targeted imaging approaches are reviewed, and their promising future perspectives are discussed

A Facile and Reproducible Synthesis of Near-Infrared Fluorescent Conjugates with Small Targeting Molecules for Microbial Infection Imaging

Optical imaging of microbial infections, based on the detection of targeted fluorescent probes, offers high sensitivity and resolution with a relatively simple and portable setup. As the absorbance of near-infrared (NIR) light by human tissues is minimal, using respective tracers, such as IRdye800CW, enables imaging deeper target sites in the body. Herein, we present a general strategy for the conjugation of IRdye800CW and IRdye700DX to small molecules (vancomycin and amphotericin B) to provide conjugates targeted toward bacterial and fungal infections for optical imaging and photodynamic therapy. In particular, we present how the use of coupling agents (such as HBTU or HATU) leads to high yields (over 50%) in the reactions of amines and IRDye-NHS esters and how precipitation can be used as a convenient purification strategy to remove excess of the targeting molecule after the reaction. The high selectivity of the synthesized model compound Vanco-800CW has been proven in vitro, and the development of analogous agents opens up new possibilities for diagnostic and theranostic purposes. In times of increasing microbial resistance, this research gives us access to a platform of new fluorescent tracers for the imaging of infections, enabling early diagnosis and respective treatment

Sonication of Vascular Grafts and Endografts to Diagnose Vascular Graft Infection:a Head-To-Head Comparison with Conventional Culture and Its Clinical Impact

Vascular graft and endograft infection (VGEI) is a severe complication associated with high mortality and is often challenging to diagnose. For the definitive microbiological diagnosis, sonication of vascular grafts may increase the microbiological yield of these biofilm-associated infections. The objective of this study was to determine whether sonication of explanted vascular grafts and endografts results in a higher diagnostic accuracy than conventional culture methods and aids in clinical decision-making. A prospective diagnostic study was performed comparing conventional culture with sonication culture of explanted vascular grafts in patients treated for VGEI. Explanted (endo)grafts were cut in halves and were either subjected to sonication or conventional culture. Criteria based on the Management of Aortic Graft Infection Collaboration (MAGIC) case definition of VGEI were used for definitive diagnosis. The relevance of sonication cultures was assessed by expert opinion to determine the clinical impact on decision-making. Fifty-seven vascular (endo)graft samples from 36 patients (four reoperations; 40 episodes) treated for VGEI were included; 32 episodes were diagnosed with VGEI. Both methods showed a positive culture in 81% of the cases. However, sonication culture detected clinically relevant microorganisms that went unnoticed by conventional culturing in 9 out of 57 samples (16%, 8 episodes) and provided additional relevant information regarding growth densities in another 11 samples (19%, 10 episodes). Sonication of explanted vascular grafts and endografts improves the microbiological yield and aids in the clinical decision-making for patients with a suspected VGEI compared to conventional culture alone.</p

The smart activatable P2&amp;3TT probe allows accurate, fast, and highly sensitive detection of Staphylococcus aureus in clinical blood culture samples

Staphylococcus aureus bacteraemia (SAB) is associated with high mortality and morbidity rates. Yet, there is currently no adequate diagnostic test for early and rapid diagnosis of SAB. Therefore, this study was aimed at exploring the potential for clinical implementation of a nuclease-activatable fluorescent probe for early diagnosis of SAB. To this end, clinical blood culture samples from patients with bloodstream infections were incubated for 1 h with the "smart" activatable P2&3TT probe, the total assay time being less than 2 h. Cleavage of this probe by the secreted S. aureus enzyme micrococcal nuclease results in emission of a readily detectable fluorescence signal. Incubation of S. aureus-positive blood culture samples with the P2&3TT probe resulted in 50-fold higher fluorescence intensity levels than incubation with culture-negative samples. Moreover, incubation of the probe with non-S. aureus-positive blood cultures yielded essentially background fluorescence intensity levels for cultures with Gram-negative bacteria, and only ~ 3.5-fold increased fluorescence intensity levels over background for cultures with non-S. aureus Gram-positive bacteria. Importantly, the measured fluorescence intensities were dose-dependent, and a positive signal was clearly detectable for S. aureus-positive blood cultures with bacterial loads as low as ~ 7,000 colony-forming units/mL. Thus, the nuclease-activatable P2&3TT probe distinguishes clinical S. aureus-positive blood cultures from non-S. aureus-positive blood cultures and culture-negative blood, accurately, rapidly and with high sensitivity. We conclude that this probe may enhance the diagnosis of SAB

Ex Vivo Tracer Efficacy in Optical Imaging of Staphylococcus Aureus Nuclease Activity

The key to effective treatment of bacterial infections is a swift and reliable diagnosis. Current clinical standards of bacterial diagnosis are slow and laborious. There are several anatomical imaging modalities that can detect inflammation, but none can distinguish between bacterial and sterile inflammation. Novel tracers such as smart activatable fluorescent probes represent a promising development that allow fast and specific testing without the use of ionizing radiation. Previously, a smart activatable probe was developed that is a substrate for the micrococcal nuclease as produced by Staphylococcus aureus. In the present study, the function of this probe was validated. Practical applicability in terms of sensitivity was assessed by incubation of the probe with 26 clinical S. aureus isolates, and probe specificity was verified by incubation with 30 clinical isolates and laboratory strains of various bacterial pathogens. The results show that the nuclease-specific probe was activated by all tested S. aureus isolates and laboratory strains with a threshold of ~106-107 cells/mL. The probe was also activated by certain opportunistic staphylococci. We therefore propose that the studied nuclease probe represents a significant step forward to address the need for a rapid, practical, and precise method to detect infections caused by S. aureus

Yeast Infections after Esophagectomy:A Retrospective Analysis

Esophageal malignancy is a disease with poor prognosis. Curative therapy incorporates surgery and is burdensome with high rates of infection morbidity and mortality. The role of yeast as causative organisms of post-esophagectomy infections is poorly defined. Consequently, the benefits of specific antifungal prophylactic therapy in improving patient outcome are unclear. Therefore, this study aimed at investigating the incidence of yeast infections at the University Medical Center Groningen among 565 post-esophagectomy patients between 1991 and 2017. The results show that 7.3% of the patients developed a yeast infection after esophageal resection with significantly increased incidence among patients suffering from diabetes mellitus. For patients with yeast infections, higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores, more frequent intensive care unit readmissions, prolonged hospital stays and higher mortality rates were observed. One-year survival was significantly lower for patients with a yeast infection, as well as diabetes mellitus and yeast-positive pleural effusion. We conclude that the incidence of yeast infections following esophagectomy is considerable, and that patients with diabetes mellitus are at increased risk. Furthermore, yeast infections are associated with higher complication rates and mortality. These observations encourage further prospective investigations on the possible benefits of antifungal prophylactic therapy for esophagectomy patients

Image-guided in situ detection of bacterial biofilms in a human prosthetic knee infection model:a feasibility study for clinical diagnosis of prosthetic joint infections

Purpose Due to an increased human life expectancy, the need to replace arthritic or dysfunctional joints by prosthetics is higher than ever before. Prosthetic joints are unfortunately inherently susceptible to bacterial infection accompanied by biofilm formation. Accurate and rapid diagnosis is vital to increase therapeutic success. Yet, established diagnostic modalities cannot directly detect bacterial biofilms on prostheses. Therefore, the present study was aimed at investigating whether arthroscopic optical imaging can accurately detect bacterial biofilms on prosthetic joints. Methods Here, we applied a conjugate of the antibiotic vancomycin and the near-infrared fluorophore IRDye800CW, in short vanco-800CW, in combination with arthroscopic optical imaging to target and visualize biofilms on infected prostheses. Results We show in a human post-mortem prosthetic knee infection model that a staphylococcal biofilm is accurately detected in real time and distinguished from sterile sections in high resolution. In addition, we demonstrate that biofilms associated with the clinically most relevant bacterial species can be detected using vanco-800CW. Conclusion The presented image-guided arthroscopic approach provides direct visual diagnostic information and facilitates immediate appropriate treatment selection