Citation Details

Journal Article

OsteoSense

Preclinical models for musculoskeletal disorders are critical for understanding the pathogenesis of bone and joint disorders in humans and the development of effective therapies. The assessment of these models primarily relies on morphological analysis which remains time consuming and costly, requiring large numbers of animals to be tested through different stages of the disease. The implementation of preclinical imaging represents a keystone in the refinement of animal models allowing longitudinal studies and enabling a powerful, non-invasive and clinically translatable way for monitoring disease progression in real time. Our aim is to highlight examples that demonstrate the advantages and limitations of different imaging modalities including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and optical imaging. All of which are in current use in preclinical skeletal research. MRI can provide high resolution of soft tissue structures, but imaging requires comparatively long acquisition times; hence, animals require long-term anaesthesia. CT is extensively used in bone and joint disorders providing excellent spatial resolution and good contrast for bone imaging. Despite its excellent structural assessment of mineralized structures, CT does not provide in vivo functional information of ongoing biological processes. Nuclear medicine is a very promising tool for investigating functional and molecular processes in vivo with new tracers becoming available as biomarkers. The combined use of imaging modalities also holds significant potential for the assessment of disease pathogenesis in animal models of musculoskeletal disorders, minimising the use of conventional invasive methods and animal redundancy.

Journal Article

Animals; Bioware; Bone Marrow; Bone Marrow Cells; Disease Models, Animal; Female; Host-Pathogen Interactions; Humans; Knee Joint; Listeria monocytogenes; Listeriosis; Mice; Mice, Inbred BALB C; Mutation; pXen-5; Tibia

Murine listeriosis is one of the most comprehensive and well-studied models of infection, and Listeria monocytogenes has provided seminal information regarding bacterial pathogenesis. However, many aspects of the mouse model remain poorly understood, including carrier states and chronic colonization which represent important features of the spectrum of host-pathogen interaction. Bone marrow has recently been shown to harbor L. monocytogenes, which spreads from this location to the central nervous system. Bone could, therefore, be an important chronic reservoir, but this infection is difficult to study because it involves only a few bacteria and the extent of infection cannot be assessed until after the animal is sacrificed. We employed in vivo bioluminescence imaging to localize L. monocytogenes bone infections over time in live mice, revealing that the bacteria grow in discrete foci. These lesions can persist in many locations in the legs of mice and are not accompanied by a histological indication such as granuloma or a neutrophil infiltratate. We demonstrate that highly attenuated hly mutants, which have defective intracellular replication, are capable of prolonged focal infection of the bone marrow for periods of up to several weeks. These results support the recently proposed hypothesis that the bone marrow is a unique niche for L. monocytogenes.

Journal Article

Bioware; Gene Silencing; PC-3M-luc; Peptides; Proteins; RNA Interference; Transfection

RNA interference (RNAi) is an attractive phenomenon for practical use that specifically inhibits gene expression and is carried out by small double-stranded RNAs (dsRNAs) including small interfering RNA (siRNA) or short hairpin RNA (shRNA). In addition, RNAi is of great interest for clinical use to cure refractory diseases related to the expression of a specific gene. To achieve gene silencing in the body, a sufficient amount of dsRNA must be delivered and internalized into target cells. However, dsRNAs have a large molecular weight and net negative charge, which limits their membrane-permeating ability. Moreover, dsRNAs are rapidly degraded by endonucleses in the body. Therefore, for the efficient delivery of dsRNAs, many approaches based on drug delivery systems have been carried out. In this review, we focus on recent reports about the application of functional peptides and proteins designed for the efficient delivery of dsRNAs.

Journal Article

Inflammation; Calcification; Atherosclerosis; Molecular imaging; in vivo imaging; ProSense; OsteoSense

Optical molecular imaging represents an emerging method that can detect pathobiological processes in vivo at the cellular and molecular levels, offering a dynamic link between imaging and biology. This review discusses the impact of molecular imaging methods in atherosclerosis research and preventive medicine and focuses on the inflammation-dependent mechanisms of arterial calcification.

Journal Article

N/A

BACKGROUND: Lung cancer is the leading cause of cancer-related death in the United States, with more than half of the cancers are located peripherally. Computed tomography (CT) has been utilized in the last decade to detect early peripheral lung cancer. However, due to the high false diagnosis rate of CT, further biopsy is often necessary to confirm cancerous cases. This renders intervention for peripheral lung nodules (especially for small peripheral lung cancer) difficult and time-consuming, and it is highly desirable to develop new, on-the-spot earlier lung cancer diagnosis and treatment strategies. PURPOSE: The objective of this study is to develop a minimally invasive multimodality image-guided (MIMIG) intervention system to detect lesions, confirm small peripheral lung cancer, and potentially guide on-the-spot treatment at an early stage. Accurate image guidance and real-time optical imaging of nodules are thus the key techniques to be explored in this work. METHODS: The MIMIG system uses CT images and electromagnetic (EM) tracking to help interventional radiologists target the lesion efficiently. After targeting the lesion, a fiber-optic probe coupled with optical molecular imaging contrast agents is used to confirm the existence of cancerous tissues on-site at microscopic resolution. Using the software developed, pulmonary vessels, airways, and nodules can be segmented and visualized for surgical planning; the segmented results are then transformed onto the intra-procedural CT for interventional guidance using EM tracking. Endomicroscopy through a fiber-optic probe is then performed to visualize tumor tissues. Experiments using IntegriSense 680 fluorescent contrast agent labeling alphavbeta3 integrin were carried out for rabbit lung cancer models. Confirmed cancers could then be treated on-the-spot using radio-frequency ablation (RFA). RESULTS: The prototype system is evaluated using the rabbit VX2 lung cancer model to evaluate the targeting accuracy, guidance efficiency, and performance of molecular imaging. Using this system, we achieved an average targeting accuracy of 3.04 mm, and the IntegriSense signals within the VX2 tumors were found to be at least two-fold higher than those of normal tissues. The results demonstrate great potential for applying the system in human trials in the future if an optical molecular imaging agent is approved by the Food and Drug Administration (FDA). CONCLUSIONS: The MIMIG system was developed for on-the-spot interventional diagnosis of peripheral lung tumors by combining image-guidance and molecular imaging. The system can be potentially applied to human trials on diagnosing and treating earlier stage lung cancer. For current clinical applications, where a biopsy is unavoidable, the MIMIG system without contrast agents could be used for biopsy guidance to improve the accuracy and efficiency.