Intravital imaging of skin infections

Development of a novel technology for long-term culture and live imaging of excised human tissue

An integrated understanding of the structure and reactivity of cells, extracellular matrices, and appendages is important for elucidating their functions and mechanisms in our bodies. Three-dimensional imaging using immuno-fluorescent staining with decolorization technology aids in comprehending the internal structure of human organs. However, live imaging of skin dynamics using animal models is highly invasive and unsuitable for humans. The aim of this study was to establish a non-invasive live imaging method for excised human tissue. In this study, to maintain excised human skin tissue in a state similar to a living body, we developed a novel microneedle-based culture technique. This method was evaluated for cytotoxicity detection, inflammatory cytokine release, and tissue morphology. Using microneedles, we cultured excised skin tissue and observed cellular organelles, reactive oxygen species (ROS), and fibrous structures via fluorescent probes and autofluorescence. The microneedle technique prevented cell death and inflammation, enabling long-term culturing. We live-imaged various skin cells, extracellular matrices, and appendage structures, visualizing epidermal cell membranes, mitochondria, and ROS. Collagen and elastin fibers were observed using autofluorescence and second harmonic generation. This approach enabled live imaging for 5 d, providing insights into skin metabolism, regeneration, and responses to stimuli and drugs, ultimately advancing dermatological research.

Neutrophils under the microscope: neutrophil dynamics in infection, inflammation, and cancer revealed using intravital imaging

Neutrophils rapidly respond to inflammation resulting from infection, injury, and cancer. Intravital microscopy (IVM) has significantly advanced our understanding of neutrophil behavior, enabling real-time visualization of their migration, interactions with pathogens, and coordination of immune responses. This review delves into the insights provided by IVM studies on neutrophil dynamics in various inflammatory contexts. We also examine the dual role of neutrophils in tumor microenvironments, where they can either facilitate or hinder cancer progression. Finally, we highlight how computational modeling techniques, especially agent-based modeling, complement experimental data by elucidating neutrophil kinetics at the level of individual cells as well as their collective behavior. Understanding the role of neutrophils in health and disease is essential for developing new strategies for combating infection, inflammation and cancer.

Imaging viral infection in vivo to gain unique perspectives on cellular antiviral immunity

The past decade has seen near continual global public health crises caused by emerging viral infections. Extraordinary increases in our knowledge of the mechanisms underlying successful antiviral immune responses in animal models and during human infection have accompanied these viral outbreaks. Keeping pace with the rapidly advancing field of viral immunology, innovations in microscopy have afforded a previously unseen view of viral infection occurring in real-time in living animals. Here, we review the contribution of intravital imaging to our understanding of cell-mediated immune responses to viral infections, with a particular focus on studies that visualize the antiviral effector cells responding to infection as well as virus-infected cells. We discuss methods to visualize viral infection in vivo using intravital microscopy (IVM) and significant findings arising through the application of IVM to viral infection. Collectively, these works underscore the importance of developing a comprehensive spatial understanding of the relationships between immune effectors and virus-infected cells and how this has enabled unique discoveries about virus/host interactions and antiviral effector cell biology.

Epigenetic basis of diabetic vasculopathy

Type 2 diabetes mellitus (T2DM) causes peripheral vascular disease because of which several blood-borne factors, including vital nutrients fail to reach the affected tissue. Tissue epigenome is sensitive to chronic hyperglycemia and is known to cause pathogenesis of micro- and macrovascular complications. These vascular complications of T2DM may perpetuate the onset of organ dysfunction. The burden of diabetes is primarily because of a wide range of complications of which nonhealing diabetic ulcers represent a major component. Thus, it is imperative that current research help recognize more effective methods for the diagnosis and management of early vascular injuries. This review addresses the significance of epigenetic processes such as DNA methylation and histone modifications in the evolution of macrovascular and microvascular complications of T2DM.