Synthesis and Biological Evaluation of a Radiolabeled PET (Positron Emission Tomography) Probe for Visualization of In Vivo α-Fucosidase Expression.

The acidic hydrolase α-fucosidase (AF) is a biomarker for maladies such as cancer and inflammation. The most advanced probes for α-fucosidase are unfortunately constrained to ex vivo or in vitro applications. The in vivo detection and quantification of AF using positron emission tomography would allow for better discovery and diagnosis of disease as well as provide better understanding of disease progression.

Lactate Production Precedes Inflammatory Cell Recruitment in Arthritic Ankles: an Imaging Study.

Purpose: Inflammation is involved in many disease processes. However, accurate imaging tools permitting diagnosis and characterization of inflammation are still missing. As inflamed tissues exhibit a high rate of glycolysis, pyruvate metabolism may offer a unique approach to follow the inflammatory response and disease progression.

Visualization and quantification of homing kinetics of myeloid-derived suppressor cells in primary and metastatic cancer.

Myeloid-derived suppressor cells (MDSCs) are immunosuppressive cells of the myeloid compartment and major players in the tumor microenvironment (TME). With increasing numbers of studies describing MDSC involvement in cancer immune escape, cancer metastasis and the dampening of immunotherapy responses, MDSCs are of high interest in current cancer therapy research. Although heavily investigated in the last decades, the migration dynamics of MDSC subpopulations in tumor- or metastases-bearing mice have not yet been studied extensively.

Weak Agonistic LPS Restores Intestinal Immune Homeostasis.

Generated by gram-negative bacteria, lipopolysaccharides (LPSs) are one of the most abundant and potent immunomodulatory substances present in the intestinal lumen. Interaction of agonistic LPS with the host myeloid-differentiation-2/Toll-like receptor 4 (MD-2/TLR4) receptor complex results in nuclear factor κB (NF-κB) activation, followed by the robust induction of pro-inflammatory immune responses. Here we have isolated LPS from a common gut commensal, Bacteroides vulgatus mpk (BVMPK), which provides only weak agonistic activity.

Cysteine-type cathepsins promote the effector phase of acute cutaneous delayed-type hypersensitivity reactions.

Cysteine-type cathepsins such as cathepsin B are involved in various steps of inflammatory processes such as antigen processing and angiogenesis. Here, we uncovered the role of cysteine-type cathepsins in the effector phase of T cell-driven cutaneous delayed-type hypersensitivity reactions (DTHR) and the implication of this role on therapeutic cathepsin B-specific inhibition. : Wild-type, cathepsin B-deficient (Ctsb) and cathepsin Z-deficient (Ctsz) mice were sensitized with 2,4,6-trinitrochlorobenzene (TNCB) on the abdomen and challenged with TNCB on the right ear to induce acute and chronic cutaneous DTHR.

Imaging fibrosis in inflammatory diseases: targeting the exposed extracellular matrix.

In a variety of diseases, from benign to life-threatening ones, inflammation plays a major role. Monitoring the intensity and extent of a multifaceted inflammatory process has become a cornerstone in diagnostics and therapy monitoring. However, the current tools lack the ability to provide insight into one of its most crucial aspects, namely, the alteration of the extracellular matrix (ECM).

Evaluation of the therapeutic potential of the selective p38 MAPK inhibitor Skepinone-L and the dual p38/JNK 3 inhibitor LN 950 in experimental K/BxN serum transfer arthritis.

Background: Mitogen-activated protein kinase (MAPK) signaling plays an important role in inflammatory diseases such as rheumatoid arthritis (RA).The aim of our study was to elucidate the therapeutic potential of the highly selective p38 MAPK inhibitor Skepinone-L and the dual inhibitor LN 950 (p38 MAPK and JNK 3) in the K/BxN serum transfer model of RA. Additionally, we aimed to monitor MAPK treatment non-invasively in vivo using the hypoxia tracer [F]fluoromisonidazole ([F]FMISO) and positron emission tomography (PET).

Comparative immuno-Cerenkov luminescence and -PET imaging enables detection of PSMA tumors in mice using Cu-radiolabeled monoclonal antibodies.

Here, we describe immuno-Cerenkov luminescence imaging (immuno-CLI) with a specific monoclonal antibody-based tracer for the detection of prostate tumors, which is used in preclinical positron emission tomography (PET) imaging. As PET isotopes generate a continuous spectrum of light in the ultraviolet/visible (UV/vis) wavelength range (Cerenkov luminescence, CL) in dielectric materials and consequently inside living tissues, these isotopes can also be detected by luminescence imaging performed with optical imaging (OI) systems. Imaging tumors with tracers that are specifically binding to a tumor-associated antigen can increase diagnostic accuracy, enables monitoring of treatment efficacy, and can be advantageous compared to radiolabeled small molecules used in PET-oncology such as 2-deoxy-2-[F]-fluoro-D-glucose ([F]FDG; glucose metabolism) or [C]choline (membrane synthesis) which was used to image prostate cancer.

CCR2-dependent Gr1 monocytes promote kidney injury in shiga toxin-induced hemolytic uremic syndrome in mice.

The hemolytic uremic syndrome (HUS) is a life-threatening disease of the kidney that is induced by shiga toxin-producing E.coli. Major changes in the monocytic compartment and in CCR2-binding chemokines have been observed.

Standardization of Small Animal Imaging-Current Status and Future Prospects.

The benefit of small animal imaging is directly linked to the validity and reliability of the collected data. If the data (regardless of the modality used) are not reproducible and/or reliable, then the outcome of the data is rather questionable. Therefore, standardization of the use of small animal imaging equipment, as well as of animal handling in general, is of paramount importance.

Non-invasive In Vivo Fluorescence Optical Imaging of Inflammatory MMP Activity Using an Activatable Fluorescent Imaging Agent.

This paper describes a non-invasive method for imaging matrix metalloproteinases (MMP)-activity by an activatable fluorescent probe, via in vivo fluorescence optical imaging (OI), in two different mouse models of inflammation: a rheumatoid arthritis (RA) and a contact hypersensitivity reaction (CHR) model. Light with a wavelength in the near infrared (NIR) window (650 - 950 nm) allows a deeper tissue penetration and minimal signal absorption compared to wavelengths below 650 nm. The major advantages using fluorescence OI is that it is cheap, fast and easy to implement in different animal models.

Acceleration of the nonlinear dynamics in p-doped indium phosphide nanoscale resonators.

We demonstrated a twofold acceleration of the fast time constant characterizing the recovery of a p-doped indium-phosphide photonic crystal all-optical gate. Time-resolved spectral analysis is compared to a three-dimensional drift-diffusion model for the carrier dynamics, demonstrating the transition from the ambipolar to the faster minority carrier dominated diffusion regime. This opens the perspective for faster yet efficient nanophotonic all-optical gates.

In Vivo Hypoxia PET Imaging Quantifies the Severity of Arthritic Joint Inflammation in Line with Overexpression of Hypoxia-Inducible Factor and Enhanced Reactive Oxygen Species Generation.

Hypoxia is essential for the development of autoimmune diseases such as rheumatoid arthritis (RA) and is associated with the expression of reactive oxygen species (ROS), because of the enhanced infiltration of immune cells. The aim of this study was to demonstrate the feasibility of measuring hypoxia noninvasively in vivo in arthritic ankles with PET/MRI using the hypoxia tracers F-fluoromisonidazole (F-FMISO) and F-fluoroazomycinarabinoside (F-FAZA). Additionally, we quantified the temporal dynamics of hypoxia and ROS stress using L-012, an ROS-sensitive chemiluminescence optical imaging probe, and analyzed the expression of hypoxia-inducible factors (HIFs).

Cholesterol Modification of p40-Specific Small Interfering RNA Enables Therapeutic Targeting of Dendritic Cells.

Small interfering RNA (siRNA)-based therapies allow targeted correction of molecular defects in distinct cell populations. Although efficient in multiple cell populations, dendritic cells (DCs) seem to resist siRNA delivery. Using fluorescence labeling and radiolabeling, we show that cholesterol modification enables siRNA uptake by DCs in vitro and in vivo.

A Comparative pO2 Probe and [18F]-Fluoro-Azomycinarabino-Furanoside ([18F]FAZA) PET Study Reveals Anesthesia-Induced Impairment of Oxygenation and Perfusion in Tumor and Muscle.

Methods: CT26 colon carcinoma-bearing mice were anesthetized with isoflurane (IF) or ketamine/xylazine (KX) while breathing air or oxygen (O2). We performed 10 min static PET scans 1 h, 2 h and 3 h after [18F]FAZA injection and calculated the [18F]FAZA-uptake and tumor-to-muscle ratios (T/M). In another experimental group, we placed a pO2 probe in the tumor as well as in the gastrocnemius muscle to measure the pO2 and perfusion.

Assessment of murine brain tissue shrinkage caused by different histological fixatives using magnetic resonance and computed tomography imaging.

Especially for neuroscience and the development of new biomarkers, a direct correlation between in vivo imaging and histology is essential. However, this comparison is hampered by deformation and shrinkage of tissue samples caused by fixation, dehydration and paraffin embedding. We used magnetic resonance (MR) imaging and computed tomography (CT) imaging to analyze the degree of shrinkage on murine brains for various fixatives.

In vivo optical imaging of matrix metalloproteinase activity detects acute and chronic contact hypersensitivity reactions and enables monitoring of the antiinflammatory effects of N-acetylcysteine.

The aim of this study was to determine whether the severity of contact hypersensitivity reactions (CHSRs) can be observed by noninvasive in vivo optical imaging of matrix metalloproteinase (MMP) activity and whether this is an appropriate tool for monitoring an antiinflammatory effect. Acute and chronic CHSRs were elicited by application of a 1% trinitrochlorobenzene (TNCB) solution for up to five times on the right ear of TNCB-sensitized mice. N-Acetylcysteine (NAC)-treated and sham-treated mice were monitored by measuring ear swelling and optical imaging of MMP activity.

Labelling and tracking of human mesenchymal stromal cells in preclinical studies and large animal models of degenerative diseases.

Success of stem cell therapies were reported in different medical disciplines, including haematology, rheumatology, orthopaedic surgery, traumatology, and others. Currently, more than 4000 clinical trials using stem cells have been completed or are underway, among which 378 investigated or are at present investigating mesenchymal stromal cells (MSCs). The majority of clinical trials using stem- or progenitor- cells, including hematopoietic stem cells and MSCs, target the immune system.

Impact of anesthetics on 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) uptake in animal models of cancer and inflammation.

The aim of this study was to evaluate the impact of different anesthetics on 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) uptake in carcinomas and arthritic ankles. To determine the amount of [18F]FLT uptake in subcutaneous CT26 colon carcinomas or arthritic ankles, spontaneously room air/medical air-breathing mice were anesthetized with isoflurane, a combination of medetomidine/midazolam, or ketamine/xylazine. Mice were kept conscious or anesthetized during [18F]FLT uptake before the 10-minute static positron emission tomographic (PET) investigations.

In vivo imaging of cell proliferation enables the detection of the extent of experimental rheumatoid arthritis by 3'-deoxy-3'-18f-fluorothymidine and small-animal PET.

Unlabelled: The aim of this work was to study the feasibility of measuring cell proliferation noninvasively in vivo during different stages of experimental arthritis using the PET proliferation tracer 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT).

Methods: We injected mice with serum containing glucose-6-phosphate-isomerase-specific antibodies to induce experimental arthritis, and we injected control mice with control serum. Animals injected with (18)F-FLT 1, 3, 6, and 8 d after the onset of disease were analyzed in vivo by PET, PET/CT, or PET/MR imaging followed by autoradiography analysis.

Epigenetics-related genes in prostate cancer: expression profile in prostate cancer tissues, androgen-sensitive and -insensitive cell lines.

Epigenetic changes have been suggested to drive prostate cancer (PCa) development and progression. Therefore, in this study, we aimed to identify novel epigenetics-related genes in PCa tissues, and to examine their expression in metastatic PCa cell lines. We analyzed the expression of epigenetics-related genes via a clustering analysis based on gene function in moderately and poorly differentiated PCa glands compared to normal glands of the peripheral zone (prostate proper) from PCa patients using Whole Human Genome Oligo Microarrays.

ERG is specifically associated with ETS-2 and ETV-4, but not with ETS-1, in prostate cancer.

The erythroblast transformation-specific (ETS) family of transcription factors plays important roles in both physiological and pathological conditions. Even though many studies have focused on single ETS factors within a single tissue and within the context of specific promoters, the functional impact of multiple ETS members present within a specific cell type has not yet been investigated, especially in prostate cancer (PCa). As the most prominent gene rearrangement in PCa leads to the overexpression of the ETS-related gene (ERG), the aim of this study was to investigate whether ERG is part of a complex integrated transcriptional network that involves other ETS factors.

Feasibility of sequential PET/MRI using a state-of-the-art small animal PET and a 1 T benchtop MRI.

Purpose: Combined PET/MRI studies receive increasing attention, as their combination allows deeper insight into disease progression. We evaluated a novel 1 T benchtop MRI scanner (1T-MRI) for its use in sequential PET/MRI studies.

Procedures: Phantom studies were performed, addressing the attenuation caused by the MRI coils.

Oxygen breathing affects 3'-deoxy-3'-18F-fluorothymidine uptake in mouse models of arthritis and cancer.

Unlabelled: Noninvasive in vivo imaging of biologic processes using PET is an important tool in preclinical studies. We observed significant differences in 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) uptake in arthritic ankles and carcinomas between dynamic and static PET measurements when mice breathed oxygen. Thus, we suspected that air or oxygen breathing and the anesthesia protocol might influence (18)F-FLT tracer uptake.