In Vivo Dual Fluorescence Imaging to Detect Joint Destruction

Optical Imaging of Matrix Metalloproteinases Activity in Prostate Tumors in Mice

The molecular characterization of cancer could have significant clinical benefits, including early diagnosis, making treatment decisions, and monitoring therapeutic response. In this regard, noninvasive assessment of expression/activity of specific molecules in tumors could be vital in managing cancer. Optical probes have demonstrated promise in the molecular imaging of cancer. Here, we have described a method to noninvasively assess the activity of matrix metalloproteinases (MMPs) in human prostate tumors in mice. We used an activatable probe MMPSense™ 750 FAST (MMPSense750) with fluorescent properties in the near-infrared (NIR) range with peak excitation at ~749 nm and peak emission ~775 nm. These optical properties offer the advantage of a higher depth of detection. This probe has shown immense potential in imaging MMPs activity in deeper tissue with high target-specific signal and low background autofluorescence. Therefore, this probe could be valuable in assessing MMPs activity in primary tumors and metastasis.

Understanding Early-Stage Posttraumatic Osteoarthritis for Future Prospects of Diagnosis: from Knee to Temporomandibular Joint

PURPOSE OF REVIEW

Many mechanical load-bearing joints of the body are prone to posttraumatic osteoarthritis (PTOA), including the knee joint and temporomandibular joint (TMJ). Early detection of PTOA can be beneficial in prevention or alleviating further progression of the disease.

RECENT FINDINGS

Various mouse models, similar to those used in development of novel diagnosis strategies for early stages of OA, have been proposed to study early PTOA. While many studies have focused on OA and PTOA in the knee joint, early diagnostic methods for OA and PTOA of the TMJ are still not well established. Previously, we showed that fluorescent near-infrared imaging can diagnose inflammation and cartilage damage in mouse models of knee PTOA. Here we propose that the same approach can be used for early diagnosis of TMJ-PTOA. In this review, we present a brief overview of PTOA, application of relevant mouse models, current imaging methods available to examine TMJ-PTOA, and the prospects of near-infrared optical imaging to diagnose early-stage TMJ-OA.

Ameliorating effects of Gö6976, a pharmacological agent that inhibits protein kinase D, on collagen-induced arthritis

Toll-like receptor (TLR) signaling can contribute to the pathogenesis of arthritis. Disruption of TLR signaling at early stages of arthritis might thereby provide an opportunity to halt the disease progression and ameliorate outcomes. We previously found that Gö6976 inhibits TLR-mediated cytokine production in human and mouse macrophages by inhibiting TLR-dependent activation of protein kinase D1 (PKD1), and that PKD1 is essential for proinflammatory responses mediated by MyD88-dependent TLRs. In this study, we investigated whether PKD1 contributes to TLR-mediated proinflammatory responses in human synovial cells, and whether Gö6976 treatment can suppress the development and progression of type II collagen (CII)-induced arthritis (CIA) in mouse. We found that TLR/IL-1R ligands induced activation of PKD1 in human fibroblast-like synoviocytes (HFLS). TLR/IL-1R-induced expression of cytokines/chemokines was substantially inhibited in Gö6976-treated HFLS and PKD1-knockdown HFLS. In addition, serum levels of anti-CII IgG antibodies, and the incidence and severity of arthritis after CII immunization were significantly reduced in mice treated daily with Gö6976. Synergistic effects of T-cell receptor and TLR, as well as TLR alone, on spleen cell proliferation and cytokine production were significantly inhibited in the presence of Gö6976. Our results suggest a possibility that ameliorating effects of Gö6976 on CIA may be due to its ability to inhibit TLR/IL-1R-activated PKD1, which might play an important role in proinflammatory responses in arthritis, and that PKD1 could be a therapeutic target for inflammatory arthritis.

A NIR-II fluorescent probe for articular cartilage degeneration imaging and osteoarthritis detection

Articular cartilage (AC) is a complex water-bearing tissue consisting of chondrocytes, proteoglycans, and collagen. AC degeneration, which occurs in the early stage and throughout the entire course of osteoarthritis (OA), is one of the main pathological changes of OA. However, current clinical approaches are unable to detect AC degradation during the early stage of OA. Herein, a novel NIR-II probe, CH1055-WL, was developed with an organic fluorophore (CH1055) and type II collagen-binding peptide (WYRGRL) for AC targeting and degeneration imaging. In vitro and in vivo imaging studies demonstrated that CH1055-WL specifically bound to AC and permitted sensitive detection of age-related or surgically induced AC degeneration in living mice. In vitro imaging of cartilage samples from pig knee joint and in vivo imaging of live mice with the probe administered via local injection in joint cavities demonstrated that CH1055-WL specifically and efficiently bound to AC. Further evaluation of CH1055-WL revealed sensitive detection of age-related AC degeneration and surgically induced AC degeneration in living mice. Our results indicated that the cartilage-targeting probe CH1055-WL allowed visual monitoring of AC degeneration in living subjects, thus displaying promise for early OA detection.

Localization of near-infrared labeled antibodies to the central nervous system in experimental autoimmune encephalomyelitis

Antibodies, including antibodies to the RNA binding protein heterogeneous nuclear ribonucleoprotein A1, have been shown to contribute to the pathogenesis of multiple sclerosis, thus it is important to assess their biological activity using animal models of disease. Near-infrared optical imaging of fluorescently labeled antibodies and matrix metalloproteinase activity were measured and quantified in an animal model of multiple sclerosis, experimental autoimmune encephalomyelitis. We successfully labeled, imaged and quantified the fluorescence signal of antibodies that localized to the central nervous system of mice with experimental autoimmune encephalomyelitis. Fluorescently labeled anti-heterogeneous nuclear ribonucleoprotein A1 antibodies persisted in the central nervous system of mice with experimental autoimmune encephalomyelitis, colocalized with matrix metalloproteinase activity, correlated with clinical disease and shifted rostrally within the spinal cord, consistent with experimental autoimmune encephalomyelitis being an ascending paralysis. The fluorescent antibody signal also colocalized with matrix metalloproteinase activity in brain. Previous imaging studies in experimental autoimmune encephalomyelitis analyzed inflammatory markers such as cellular immune responses, dendritic cell activity, blood brain barrier integrity and myelination, but none assessed fluorescently labeled antibodies within the central nervous system. This data suggests a strong association between autoantibody localization and disease. This system can be used to detect other antibodies that might contribute to the pathogenesis of autoimmune diseases of the central nervous system including multiple sclerosis.

Drug-Free ROS Sponge Polymeric Microspheres Reduce Tissue Damage from Ischemic and Mechanical Injury

The inherent antioxidant function of poly(propylene sulfide) (PPS) microspheres (MS) was dissected for different reactive oxygen species (ROS), and therapeutic benefits of PPS-MS were explored in models of diabetic peripheral arterial disease (PAD) and mechanically induced post-traumatic osteoarthritis (PTOA). PPS-MS (∼1 μm diameter) significantly scavenged hydrogen peroxide (H2O2), hypochlorite, and peroxynitrite but not superoxide in vitro in cell-free and cell-based assays. Elevated ROS levels (specifically H2O2) were confirmed in both a mouse model of diabetic PAD and in a mouse model of PTOA, with greater than 5- and 2-fold increases in H2O2, respectively. PPS-MS treatment functionally improved recovery from hind limb ischemia based on ∼15-25% increases in hemoglobin saturation and perfusion in the footpads as well as earlier remodeling of vessels in the proximal limb. In the PTOA model, PPS-MS reduced matrix metalloproteinase (MMP) activity by 30% and mitigated the resultant articular cartilage damage. These results suggest that local delivery of PPS-MS at sites of injury-induced inflammation improves the vascular response to ischemic injury in the setting of chronic hyperglycemia and reduces articular cartilage destruction following joint trauma. These results motivate further exploration of PPS as a stand-alone, locally sustained antioxidant therapy and as a material for microsphere-based, sustained local drug delivery to inflamed tissues at risk of ROS damage.

Noninvasive visualization of early osteoarthritic cartilage using targeted nanosomes in a destabilization of the medial meniscus mouse model

Background

Early stage osteoarthritis (OA) is clinically asymptomatic due to the avascular and the aneural nature of the cartilage tissue. Nevertheless, early detection of cartilage tissue is critical in order to impede the progression of OA. Hence, in order to develop effective preventive therapy for OA, diagnosis in the early stages is necessary.

Methods

To achieve this goal, we have developed targeted, fluorescent nanosomes conjugated with monoclonal anti-type II collagen antibodies (MabCII) for diagnosis of early OA. The MabCII-coated nanosomes (targeted-nanosomes) bind to the damaged cartilage explants in vitro and in vivo in an OA mouse model that mimics early stage OA. The OA mouse model was induced by destabilization of the medial meniscus (DMM) in 9–10 weeks old C57Bl/6 mice.

Results

The targeted-nanosomes enhanced the binding specificity to the cartilage tissue according to the severity of damage.

Conclusion

We show that MabCII-nanosomes can precisely detect early stage OA in the DMM mouse model. Thus, MabCII-nanosomes have the potential to be used as a non-invasive method for diagnosing the early osteoarthritic lesions.

Artificial Organs 2016: A Year in Review

In this Editor's Review, articles published in 2016 are organized by category and briefly summarized. We aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, the International Society for Mechanical Circulatory Support, the International Society for Pediatric Mechanical Cardiopulmonary Support, and the Vienna International Workshop on Functional Electrical Stimulation, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We were pleased to publish our second Virtual Issue in April 2016 on "Tissue Engineering in Bone" by Professor Tsuyoshi Takato. Our first was published in 2011 titled "Intra-Aortic Balloon Pumping" by Dr. Ashraf Khir. Other peer-reviewed Special Issues this year included contributions from the 11th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Ündar and selections from the 23rd Congress of the International Society for Rotary Blood Pumps edited by Dr. Bojan Biocina. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.

Non-invasive dual fluorescence in vivo imaging for detection of macrophage infiltration and matrix metalloproteinase (MMP) activity in inflammatory arthritic joints

Detection and intervention at an early stage is a critical factor to impede arthritis progress. Here we present a non-invasive method to detect inflammatory changes in joints of arthritic mice. Inflammation was monitored by dual fluorescence optical imaging for near-infrared fluorescent (750F) matrix-metalloproteinase activatable agent and allophycocyanin-conjugated anti-mouse CD11b. Increased intensity of allophycocyanin (indication of macrophage accumulation) and 750F (indication of matrix-metalloproteinase activity) showed a biological relationship with the arthritis severity score and the histopathology score of arthritic joints. Our results demonstrate that this method can be used to detect early stages of arthritis with minimum intervention in small animal models.