Citation Details

Journal Article

FMT; fluorescence molecular tomography; in vivo imaging; cancer

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Journal Article

Molecular imaging; Abdominal aortic aneurysm; Optical imaging; Pre-clinical; Endovascular imaging; Matrix metalloproteinase; in vivo imaging; MMPSense

Objectives: We present a method to quantify the inflammatory processes that drive abdominal aortic aneurysm (AAA) development that may help predict the rate of growth and thus guide medical and surgical management. We use an in vivo optical molecular imaging approach to quantify protease activity within the walls of AAAs in a rodent model.

Methods: AAAs were generated in mice by topical application of calcium chloride, followed by the administration of the MMP inhibitor doxycycline for 3 months. After this time period, an enzyme-activatable optical molecular imaging agent sensitive to MMP activity was administered, and MMP proteolytic activity was measured in vivo. Histology and in situ zymography were performed for validation. AAAs were also generated in rats, and MMP activity within the walls of the AAAs was also quantified endovascularly.

Results: A dose-dependent response of AAA growth rate to doxycycline administration was demonstrated, with high doses of the drug resulting in nearly complete suppression of aneurysm formation. There was a direct relationship between the rate of aneurysmal growth and measured MMP activity, with a linear best-fit well approximating the relationship. We additionally performed endovascular imaging of AAAs in rats and demonstrated a similar suppression of intramural MMP activity following doxycycline administration.

Conclusions: We present an in vivo evaluation of MMP activity within the walls of AAAs in rodents and show a direct, linear relationship between proteolytic activity and aneurysmal growth. We also illustrate that this functional imaging method can be performed endovascularly, demonstrating potential pre-clinical and clinical applications.

Journal Article

IntegriSense, Adoptive Transfer; Animals; Biological Markers/metabolism; Cell Death/genetics; Disease Models, Animal; Female; *Hematopoiesis, Extramedullary; Inflammation/immunology/metabolism; Interleukin-1beta/genetics/metabolism; Kinetics; Macrophages/cytology/*physiology; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; Monocytes/*cytology/*physiology; Myeloid Cells/metabolism; Myocardial Infarction/immunology/pathology/*physiopathology; Signal Transduction; Spleen/physiology; Stroke/immunology/metabolism; Wound Healing/physiology

Monocytes (Mo) and macrophages (MPhi) are emerging therapeutic targets in malignant, cardiovascular, and autoimmune disorders. Targeting of Mo/MPhi and their effector functions without compromising innate immunity's critical defense mechanisms first requires addressing gaps in knowledge about the life cycle of these cells. Here we studied the source, tissue kinetics, and clearance of Mo/MPhi in murine myocardial infarction, a model of acute inflammation after ischemic injury. We found that a) Mo tissue residence time was surprisingly short (20 h); b) Mo recruitment rates were consistently high even days after initiation of inflammation; c) the sustained need of newly made Mo was fostered by extramedullary monocytopoiesis in the spleen; d) splenic monocytopoiesis was regulated by IL-1beta; and e) the balance of cell recruitment and local death shifted during resolution of inflammation. Depending on the experimental approach, we measured a 24 h Mo/MPhi exit rate from infarct tissue between 5 and 13% of the tissue cell population. Exited cells were most numerous in the blood, liver, and spleen. Abrogation of extramedullary monocytopoiesis proved deleterious for infarct healing and accelerated the evolution of heart failure. We also detected rapid Mo kinetics in mice with stroke. These findings expand our knowledge of Mo/MPhi flux in acute inflammation and provide the groundwork for novel anti-inflammatory strategies for treating heart failure.

Journal Article

Animals, Bone Marrow Cells/metabolism/microbiology, Gene Expression Regulation, Intestines/metabolism, Kinetics, Lectins/chemistry, Listeria Infections/*metabolism/*prevention & control, Listeria monocytogenes/*metabolism, Mice, Mice, Inbred C57BL, Mice, Transgenic, Myeloid Differentiation Factor 88/metabolism/*physiology, Proteins/*metabolism, Recombinant Proteins/metabolism, Toll-Like Receptors/metabolism IVIS, Xenogen, Xen32

Listeria monocytogenes is a food-borne bacterial pathogen that causes systemic infection by traversing the intestinal mucosa. Although MyD88-mediated signals are essential for defense against systemic L. monocytogenes infection, the role of Toll-like receptor and MyD88 signaling in intestinal immunity against this pathogen has not been defined. We show that clearance of L. monocytogenes from the lumen of the distal small intestine is impaired in MyD88(-/-) mice. The distal ileum of wild-type (wt) mice expresses high levels of RegIII gamma, which is a bactericidal lectin that is secreted into the bowel lumen, whereas RegIII gamma expression in MyD88(-/-) mice is nearly undetectable. In vivo depletion of RegIII gamma from the small intestine of wt mice diminishes killing of luminal L. monocytogenes, whereas reconstitution of MyD88-deficient mice with recombinant RegIII gamma enhances intestinal bacterial clearance. Experiments with bone marrow chimeric mice reveal that MyD88-mediated signals in nonhematopoietic cells induce RegIII gamma expression in the small intestine, thereby enhancing bacterial killing. Our findings support a model of MyD88-mediated epithelial conditioning that protects the intestinal mucosa against bacterial invasion by inducing RegIII gamma.

Journal Article

Animals; Biofilms; Bioware; Colony-Forming Units Assay; Disease Susceptibility; Female; Luminescence; Mice; Mice, SCID; pXen-5; Staphylococcal Infections; Staphylococcus epidermidis; T-Lymphocytes; T-Lymphocytes, Cytotoxic

Staphylococcus epidermidis is the leading cause of hospital-acquired device-related infections, but there is a lack of suitable methods to investigate the pathogenesis of S. epidermidis infection. We created a bioluminescent strain of S. epidermidis and developed a subcutaneous catheter-related murine infection model for real-time monitoring of biofilm-associated infection. Additionally, we compared severely immunocompromised and immunocompetent mice, demonstrating the substantial effect of animal immune status on susceptibility to experimentally induced S. epidermidis disease. This study presents a novel approach for investigating the in vivo details of the pathogenesis of S. epidermidis infection.