Automated Spatial Omics Landscape Analysis Approach Reveals Novel Tissue Architectures in Ulcerative Colitis.

The utility of spatial omics in leveraging cellular interactions in normal and diseased states for precision medicine is hampered by a lack of strategies for matching disease states with spatial heterogeneity-guided cellular annotations. Here we use a spatial context-dependent approach that matches spatial pattern detection to cell annotation. Using this approach in existing datasets from ulcerative colitis patient colonic biopsies, we identified architectural complexities and associated difficult-to-detect rare cell types in ulcerative colitis germinal-center B cell follicles. Our approach deepens our understanding of health and disease pathogenesis, illustrates a strategy for automating nested architecture detection for highly multiplexed spatial biology data, and informs precision diagnosis and therapeutic strategies.

GPR15 in colon cancer development and anti-tumor immune responses.

Introduction: The chemoattractant receptor, G protein-coupled receptor 15 (GPR15), promotes colon homing of T cells in health and colitis. GPR15 function in colon cancer is largely unexplored, motivating our current studies. Methods: In human study, immune cells were isolated from tumor tissues and healthy surgical tumor margins (STM), and their proportions as well as expression of GPR15 was analyzed by flow cytometry. In mouse studies, colon cancer was induced in GPR15-deficient (KO) and GPR15-suficient (Het) mice using azoxymethane (AOM) and dextran sulfate sodium (DSS) solution in drinking water. Serial endoscopy was performed in mice to monitor and visualize the distal region of colon. Mice were euthanized 10 weeks after the initial DSS administration, and the colon length and the number of polyps were recorded. Next, we identified the effects of GPR15L on established tumors in the MC38-colorectal cancer (CRC) mouse model. Immune cells were isolated from the mice colons or tumors and assessed by flow cytometry. Results: Our analysis of human CRC tissue revealed a significant reduction in GPR15+ immune cell frequencies in tumors compared to 'tumor-free' surgical margins. Similarly, our data analysis using The Cancer Genome Atlas (TCGA) indicated that lower GPR15 expression is associated with poor survival in human colon cancer. In the AOM/DSS colitis-associated colon cancer model, we observed increased colonic polyps and lower survival in Gpr15 +-KO compared to Gpr15-Het mice. Analysis of immune cell infiltrates in the colonic polyps showed significantly decreased CD8+ T cells and increased IL-17+ CD4+ and IL-17+ CD8+ T cells in Gpr15-KO than in Het mice. Consistent with a protective role of GPR15, administration of GPR15L to established tumors in the MC38-CRC model increased CD45+ cell infiltration, enhanced TNFa expression on CD4+ and CD8+ T cells at the tumor site and dramatically reduced tumor burden. Discussion: Our findings highlight an important, unidentified role of the GPR15-GPR15L axis in promoting a tumor-suppressive immune microenvironment and unveils a novel, colon-specific therapeutic target for CRC.

A tissue atlas of ulcerative colitis revealing evidence of sex-dependent differences in disease-driving inflammatory cell types and resistance to TNF inhibitor therapy.

Although literature suggests that resistance to TNF inhibitor (TNFi) therapy in patients with ulcerative colitis (UC) is partially linked to immune cell populations in the inflamed region, there is still substantial uncertainty underlying the relevant spatial context. Here, we used the highly multiplexed immunofluorescence imaging technology CODEX to create a publicly browsable tissue atlas of inflammation in 42 tissue regions from 29 patients with UC and 5 healthy individuals. We analyzed 52 biomarkers on 1,710,973 spatially resolved single cells to determine cell types, cell-cell contacts, and cellular neighborhoods. We observed that cellular functional states are associated with cellular neighborhoods. We further observed that a subset of inflammatory cell types and cellular neighborhoods are present in patients with UC with TNFi treatment, potentially indicating resistant niches. Last, we explored applying convolutional neural networks (CNNs) to our dataset with respect to patient clinical variables. We note concerns and offer guidelines for reporting CNN-based predictions in similar datasets.

Highlighting the Undetectable - Fluorescence Molecular Imaging in Gastrointestinal Endoscopy.

Flexible high-definition white-light endoscopy is the current gold standard in screening for cancer and its precursor lesions in the gastrointestinal tract. However, miss rates are high, especially in populations at high risk for developing gastrointestinal cancer (e.g., inflammatory bowel disease, Lynch syndrome, or Barrett's esophagus) where lesions tend to be flat and subtle. Fluorescence molecular endoscopy (FME) enables intraluminal visualization of (pre)malignant lesions based on specific biomolecular features rather than morphology by using fluorescently labeled molecular probes that bind to specific molecular targets. This strategy has the potential to serve as a valuable tool for the clinician to improve endoscopic lesion detection and real-time clinical decision-making. This narrative review presents an overview of recent advances in FME, focusing on probe development, techniques, and clinical evidence. Future perspectives will also be addressed, such as the use of FME in patient stratification for targeted therapies and potential alliances with artificial intelligence. KEY MESSAGES: • Fluorescence molecular endoscopy is a relatively new technology that enables safe and real-time endoscopic lesion visualization based on specific molecular features rather than on morphology, thereby adding a layer of information to endoscopy, like in PET-CT imaging. • Recently the transition from preclinical to clinical studies has been made, with promising results regarding enhancing detection of flat and subtle lesions in the colon and esophagus. However, clinical evidence needs to be strengthened by larger patient studies with stratified study designs. • In the future fluorescence molecular endoscopy could serve as a valuable tool in clinical workflows to improve detection in high-risk populations like patients with Barrett's esophagus, Lynch syndrome, and inflammatory bowel syndrome, where flat and subtle lesions tend to be malignant up to five times more often. • Fluorescence molecular endoscopy has the potential to assess therapy responsiveness in vivo for targeted therapies, thereby playing a role in personalizing medicine. • To further reduce high miss rates due to human and technical factors, joint application of artificial intelligence and fluorescence molecular endoscopy are likely to generate added value.

The Tumor Immune Microenvironment in Pancreatic Ductal Adenocarcinoma: Neither Hot nor Cold.

Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic tumor and is associated with poor prognosis and treatment response. The tumor microenvironment (TME) is recognized as an important factor in metastatic progression across cancers. Despite extensive study of the TME in PDAC, the cellular and molecular signaling networks remain poorly understood, largely due to the tremendous heterogeneity across tumors. While earlier work characterized PDAC as an immunologically privileged tumor poorly recognized by the immune system, recent studies revealed the important and nuanced roles of immune cells in the pathogenesis of PDAC. Distinct lymphoid, myeloid, and stromal cell types in the TME exert opposing influences on PDAC tumor trajectory, suggesting a more complex organization than the classical "hot" versus "cold" tumor distinction. We review the pro- and antitumor immune processes found in PDAC and briefly discuss their leverage for the development of novel therapeutic approaches in the field.

In vivo visualization and molecular targeting of the cardiac conduction system.

Accidental injury to the cardiac conduction system (CCS), a network of specialized cells embedded within the heart and indistinguishable from the surrounding heart muscle tissue, is a major complication in cardiac surgeries. Here, we addressed this unmet need by engineering targeted antibody-dye conjugates directed against the CCS, allowing for the visualization of the CCS in vivo following a single intravenous injection in mice. These optical imaging tools showed high sensitivity, specificity, and resolution, with no adverse effects on CCS function. Further, with the goal of creating a viable prototype for human use, we generated a fully human monoclonal Fab that similarly targets the CCS with high specificity. We demonstrate that, when conjugated to an alternative cargo, this Fab can also be used to modulate CCS biology in vivo, providing a proof of principle for targeted cardiac therapeutics. Finally, in performing differential gene expression analyses of the entire murine CCS at single-cell resolution, we uncovered and validated a suite of additional cell surface markers that can be used to molecularly target the distinct subcomponents of the CCS, each prone to distinct life-threatening arrhythmias. These findings lay the foundation for translational approaches targeting the CCS for visualization and therapy in cardiothoracic surgery, cardiac imaging, and arrhythmia management.

Gut Microbiome in Inflammatory Bowel Disease: Role in Pathogenesis, Dietary Modulation, and Colitis-Associated Colon Cancer.

The gut microbiome has increasingly been recognized as a critical and central factor in inflammatory bowel disease (IBD). Here, we review specific microorganisms that have been suggested to play a role in the pathogenesis of IBD and the current state of fecal microbial transplants as a therapeutic strategy in IBD. We discuss specific nutritional and dietary interventions in IBD and their effects on gut microbiota composition. Finally, we examine the role and mechanisms of the gut microbiome in mediating colitis-associated colon cancer.

Antimicrobial peptides and the gut microbiome in inflammatory bowel disease.

Antimicrobial peptides (AMP) are highly diverse and dynamic molecules that are expressed by specific intestinal epithelial cells, Paneth cells, as well as immune cells in the gastrointestinal (GI) tract. They play critical roles in maintaining tolerance to gut microbiota and protecting against enteric infections. Given that disruptions in tolerance to commensal microbiota and loss of barrier function play major roles in the pathogenesis of inflammatory bowel disease (IBD) and converge on the function of AMP, the significance of AMP as potential biomarkers and novel therapeutic targets in IBD have been increasingly recognized in recent years. In this frontier article, we discuss the function and mechanisms of AMP in the GI tract, examine the interaction of AMP with the gut microbiome, explore the role of AMP in the pathogenesis of IBD, and review translational applications of AMP in patients with IBD.

SPECT/CT Imaging, Biodistribution and Radiation Dosimetry of a 177Lu-DOTA-Integrin αvß6 Cystine Knot Peptide in a Pancreatic Cancer Xenograft Model.

INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignant neoplasms, as many cases go undetected until they reach an advanced stage. Integrin αvß6 is a cell surface receptor overexpressed in PDAC. Consequently, it may serve as a target for the development of probes for imaging diagnosis and radioligand therapy. Engineered cystine knottin peptides specific for integrin αvß6 have recently been developed showing high affinity and stability. This study aimed to evaluate an integrin αvß6-specific knottin molecular probe containing the therapeutic radionuclide 177Lu for targeting of PDAC. METHODS: The expression of integrin αvß6 in PDAC cell lines BxPC-3 and Capan-2 was analyzed using RT-qPCR and immunofluorescence. In vitro competition and saturation radioligand binding assays were performed to calculate the binding affinity of the DOTA-coupled tracer loaded with and without lutetium to BxPC-3 and Capan-2 cell lines as well as the maximum number of binding sites in these cell lines. To evaluate tracer accumulation in the tumor and organs, SPECT/CT, biodistribution and dosimetry projections were carried out using a Capan-2 xenograft tumor mouse model. RESULTS: RT-qPCR and immunofluorescence results showed high expression of integrin αvß6 in BxPC-3 and Capan-2 cells. A competition binding assay revealed high affinity of the tracer with IC50 values of 1.69 nM and 9.46 nM for BxPC-3 and Capan-2, respectively. SPECT/CT and biodistribution analysis of the conjugate 177Lu-DOTA-integrin αvß6 knottin demonstrated accumulation in Capan-2 xenograft tumors (3.13 ± 0.63%IA/g at day 1 post injection) with kidney uptake at 19.2 ± 2.5 %IA/g, declining much more rapidly than in tumors. CONCLUSION: 177Lu-DOTA-integrin αvß6 knottin was found to be a high-affinity tracer for PDAC tumors with considerable tumor accumulation and moderate, rapidly declining kidney uptake. These promising results warrant a preclinical treatment study to establish therapeutic efficacy.

A protease-activated, near-infrared fluorescent probe for early endoscopic detection of premalignant gastrointestinal lesions.

Fluorescence imaging is currently being actively developed for surgical guidance; however, it remains underutilized for diagnostic and endoscopic surveillance of incipient colorectal cancer in high-risk patients. Here we demonstrate the utility and potential for clinical translation of a fluorescently labeled cathepsin-activated chemical probe to highlight gastrointestinal lesions. This probe stays optically dark until it is activated by proteases produced by tumor-associated macrophages and accumulates within the lesions, enabling their detection using an endoscope outfitted with a fluorescence detector. We evaluated the probe in multiple murine models and a human-scale porcine model of gastrointestinal carcinogenesis. The probe provides fluorescence-guided surveillance of gastrointestinal lesions and augments histopathological analysis by highlighting areas of dysplasia as small as 400 µm, which were visibly discernible with significant tumor-to-background ratios, even in tissues with a background of severe inflammation and ulceration. Given these results, we anticipate that this probe will enable sensitive fluorescence-guided biopsies, even in the presence of highly inflamed colorectal tissue, which will improve early diagnosis to prevent gastrointestinal cancers.

AND-gate contrast agents for enhanced fluorescence-guided surgery.

Surgical resection of tumours requires precisely locating and defining the margins between lesions and normal tissue. However, this is made difficult by irregular margin borders. Although molecularly targeted optical contrast agents can be used to define tumour margins during surgery in real time, the selectivity of the contrast agents is often limited by the target being expressed in both healthy and tumour tissues. Here, we show that AND-gate optical imaging probes that require the processing of two substrates by multiple tumour-specific enzymes produce a fluorescent signal with significantly improved specificity and sensitivity to tumour tissue. We evaluated the performance of the probes in mouse models of mammary tumours and of metastatic lung cancer, as well as during fluorescence-guided robotic surgery. Imaging probes that rely on multivariate activation to selectively target complex patterns of enzymatic activity should be useful in disease detection, treatment and monitoring.

Detection of Premalignant Gastrointestinal Lesions Using Surface-Enhanced Resonance Raman Scattering-Nanoparticle Endoscopy.

Cancers of the gastrointestinal (GI) tract are among the most frequent and most lethal cancers worldwide. An important reason for this high mortality is that early disease is typically asymptomatic, and patients often present with advanced, incurable disease. Even in high-risk patients who routinely undergo endoscopic screening, lesions can be missed due to their small size or subtle appearance. Thus, current imaging approaches lack the sensitivity and specificity to accurately detect incipient GI tract cancers. Here we report our finding that a single dose of a high-sensitivity surface-enhanced resonance Raman scattering nanoparticle (SERRS-NP) enables reliable detection of precancerous GI lesions in animal models that closely mimic disease development in humans. Some of these animal models have not been used previously to evaluate imaging probes for early cancer detection. The studies were performed using a commercial Raman imaging system, a newly developed mouse Raman endoscope, and finally a clinically applicable Raman endoscope for larger animal studies. We show that this SERRS-NP-based approach enables robust detection of small, premalignant lesions in animal models that faithfully recapitulate human esophageal, gastric, and colorectal tumorigenesis. This method holds promise for much earlier detection of GI cancers than currently possible and could lead therefore to marked reduction of morbidity and mortality of these tumor types.

Biodegradable fluorescent nanoparticles for endoscopic detection of colorectal carcinogenesis.

Early and comprehensive endoscopic detection of colonic dysplasia - the most clinically significant precursor lesion to colorectal adenocarcinoma - provides an opportunity for timely, minimally-invasive intervention to prevent malignant transformation. Here, the development and evaluation of biodegradable near-infrared fluorescent silica nanoparticles (FSN) is described that have the potential to improve adenoma detection during fluorescence-assisted white-light colonoscopic surveillance in rodent and human-scale models of colorectal carcinogenesis. FSNs are biodegradable (t1/2 of 2.7 weeks), well-tolerated, and enable detection and delineation of adenomas as small as 0.5 mm2 with high tumor-to-background ratios. Furthermore, in the human-scale, APC 1311/+ porcine model, the clinical feasibility and benefit of using FSN-guided detection of colorectal adenomas using video-rate fluorescence-assisted white-light endoscopy is demonstrated. Since nanoparticles of similar size (e.g., 100-150-nm) or composition (i.e., silica, silica/gold hybrid) have already been successfully translated to the clinic, and, clinical fluorescent/white light endoscopy systems are becoming more readily available, there is a viable path towards clinical translation of the proposed strategy for early colorectal cancer detection and prevention in high-risk patients.

Emerging Intraoperative Imaging Modalities to Improve Surgical Precision.

Intraoperative imaging (IOI) is performed to guide delineation and localization of regions of surgical interest. While oncological surgical planning predominantly utilizes x-ray computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US), intraoperative guidance mainly remains on surgeon interpretation and pathology for confirmation. Over the past decades however, intraoperative guidance has evolved significantly with the emergence of several novel imaging technologies, including fluorescence-, Raman, photoacoustic-, and radio-guided approaches. These modalities have demonstrated the potential to further optimize precision in surgical resection and improve clinical outcomes for patients. Not only can these technologies enhance our understanding of the disease, they can also yield large imaging datasets intraoperatively that can be analyzed by deep learning approaches for more rapid and accurate pathological diagnosis. Unfortunately, many of these novel technologies are still under preclinical or early clinical evaluation. Organizations like the Intra-Operative Imaging Study Group of the European Society for Molecular Imaging (ESMI) support interdisciplinary interactions with the aim to improve technical capabilities in the field, an approach that can succeed only if scientists, engineers, and physicians work closely together with industry and regulatory bodies to resolve roadblocks to clinical translation. In this review, we provide an overview of a variety of novel IOI technologies, discuss their challenges, and present future perspectives on the enormous potential of IOI for oncological surgical navigation.

The tyrosine kinase inhibitor imatinib mesylate suppresses uric acid crystal-induced acute gouty arthritis in mice.

Gouty arthritis is caused by the deposition of monosodium urate (MSU) crystals in joints. Despite many treatment options for gout, there is a substantial need for alternative treatments for patients unresponsive to current therapies. Tyrosine kinase inhibitors have demonstrated therapeutic benefit in experimental models of antibody-dependent arthritis and in rheumatoid arthritis in humans, but to date, the potential effects of such inhibitors on gouty arthritis has not been evaluated. Here we demonstrate that treatment with the tyrosine kinase inhibitor imatinib mesylate (imatinib) can suppress inflammation induced by injection of MSU crystals into subcutaneous air pouches or into the ankle joint of wild type mice. Moreover, imatinib treatment also largely abolished the lower levels of inflammation which developed in IL-1R1-/- or KitW-sh/W-sh mice, indicating that this drug can inhibit IL-1-independent pathways, as well as mast cell-independent pathways, contributing to pathology in this model. Imatinib treatment not only prevented ankle swelling and synovial inflammation when administered before MSU crystals but also diminished these features when administrated after the injection of MSU crystals, a therapeutic protocol more closely mimicking the clinical situation in which treatment occurs after the development of an acute gout flare. Finally, we also assessed the efficiency of local intra-articular injections of imatinib-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles in this model of acute gout. Treatment with low doses of this long-acting imatinib:PLGA formulation was able to reduce ankle swelling in a therapeutic protocol. Altogether, these results raise the possibility that tyrosine kinase inhibitors might have utility in the treatment of acute gout in humans.

Dose-dependent role of novel agents emodin and BTB14431 in colonic cancer treatment in rats.

BACKGROUND: BTB14431 is an in silico homolog to emodin. Both were found to possess anti-tumor effects in vitro. The aim of this work was to analyze the tumor suppressing effects of both molecules in an intraperitoneal (ip) and intravenous (iv) treated rat model (WAG-Rij). METHODS: A tumor cell suspension (CC531) was applied at the cecum after laparotomy and at the back. The rats where treated twice a day over 1 week with BTB14431, emodin and isotone sodium chloride solution (control). Treatment was applied iv or ip in a variety of dosages. Peripheral blood samples were taken before tumor application and on day 7. Twenty-one days after the last day of therapy animals were euthanized and tumor growth was evaluated. RESULTS: Data showed an insignificant decrease of tumor growth after iv and ip treatment with low doses of BTB14431 and emodin. Differential blood analysis showed apoptosis. Increased doses of emodin clearly raised mortality rate. CONCLUSIONS: Apoptosis was verified but no tumor-suppressing effects could be observed for iv and ip treatment with both agents in contrast to in vitro studies in our model. Establishing a successful ip treatment model for emotion and BTB14331 requires further studies.

Neutrophil myeloperoxidase diminishes the toxic effects and mortality induced by lipopolysaccharide.

Neutrophils have crucial antimicrobial functions but are also thought to contribute to tissue injury upon exposure to bacterial products, such as lipopolysaccharide (LPS). To study the role of neutrophils in LPS-induced endotoxemia, we developed a new mouse model, PMNDTR mice, in which injection of diphtheria toxin induces selective neutrophil ablation. Using this model, we found, surprisingly, that neutrophils serve to protect the host from LPS-induced lethal inflammation. This protective role was observed in conventional and germ-free animal facilities, indicating that it does not depend on a particular microbiological environment. Blockade or genetic deletion of myeloperoxidase (MPO), a key neutrophil enzyme, significantly increased mortality after LPS challenge, and adoptive transfer experiments confirmed that neutrophil-derived MPO contributes importantly to protection from endotoxemia. Our findings imply that, in addition to their well-established antimicrobial properties, neutrophils can contribute to optimal host protection by limiting the extent of endotoxin-induced inflammation in an MPO-dependent manner.

A Clinical Wide-Field Fluorescence Endoscopic Device for Molecular Imaging Demonstrating Cathepsin Protease Activity in Colon Cancer.

PURPOSE: Early and effective detection of cancers of the gastrointestinal tract will require novel molecular probes and advances in instrumentation that can reveal functional changes in dysplastic and malignant tissues. Here, we describe adaptation of a wide-field clinical fiberscope to perform wide-field fluorescence imaging while preserving its white-light capability for the purpose of providing wide-field fluorescence imaging capability to point-of-care microscopes. PROCEDURES: We developed and used a fluorescent fiberscope to detect signals from a quenched probe, BMV109, that becomes fluorescent when cleaved by, and covalently bound to, active cathepsin proteases. Cathepsins are expressed in inflammation- and tumor-associated macrophages as well as directly from tumor cells and are a promising target for cancer imaging. The fiberscope has a 1-mm outer diameter enabling validation via endoscopic exams in mice, and therefore we evaluated topically applied BMV109 for the ability to detect colon polyps in an azoxymethane-induced colon tumor model in mice. RESULTS: This wide-field endoscopic imaging device revealed consistent and clear fluorescence signals from BMV109 that specifically localized to the polypoid regions as opposed to the normal adjacent colon tissue (p < 0.004) in the murine colon carcinoma model. CONCLUSIONS: The sensitivity of detection of BMV109 with the fluorescence fiberscope suggested utility of these tools for early detection at hard-to-reach sites. The fiberscope was designed to be used in conjunction with miniature, endoscope-compatible fluorescence microscopes for dual wide-field and microscopic cancer detection.