Multi-scale optical imaging of the delayed type hypersensitivity reaction attenuated by rapamycin

Combined Oral and Topical Application of Pumpkin (Cucurbita pepo L.) Alleviates Contact Dermatitis Associated With Depression Through Downregulation Pro-Inflammatory Cytokines

Background: Depression and contact dermatitis (CD) are considered relatively common health problems that are linked with psychological stress. The antioxidant, anti-inflammatory, and antidepressant activities of pumpkin were previously reported. Objectives: This study aimed to evaluate the efficacy of the combined topical and oral application of pumpkin fruit (Cucurbita pepo L.) extract (PE) in relieving CD associated with chronic stress-induced depression and compare it to the topical pumpkin extract alone and to the standard treatment. Materials and Methods: Forty male albino rats were exposed to chronic unpredictable mild stress (CUMS) for 4 weeks for induction of depression and then exposed to (1-fluoro-2, 4-dinitrofluorobenzene, DNFB) for 2 weeks for induction of CD. Those rats were assigned into 4 groups (n = 10 each); untreated, betamethasone-treated, PE-treated and pumpkin extract cream, and oral-treated groups. Treatments were continued for 2 weeks. All groups were compared to the negative control group (n = 10). Depression was behaviorally and biochemically confirmed. Serum and mRNA levels of pro-inflammatory cytokines, such as TNF-α, IL-6, COX-2, and iNOS, were assessed. Oxidant/antioxidant profile was assessed in the serum and skin. Histopathological and immunohistochemical assessments of affected skin samples were performed. Results: Pumpkin extract, used in this study, included a large amount of oleic acid (about 56%). The combined topical and oral administration of PE significantly reduced inflammatory and oxidative changes induced by CD and depression compared to the CD standard treatment and to the topical PE alone. PE significantly alleviated CD signs and the histopathological score (p < 0.001) mostly through the downregulation of pro-inflammatory cytokines and the upregulation of antioxidants. Conclusion: Pumpkin extract, applied topically and orally, could be an alternative and/or complementary approach for treating contact dermatitis associated with depression. Further studies on volunteer patients of contact dermatitis are recommended.

Update on the development of molecular imaging and nanomedicine in China: Optical imaging

Molecular imaging has received increased attention worldwide, including in China, because it offers noninvasive characterization of widely diverse clinically significant pathologies. To achieve these goals, nanomedicine has evolved into a broad interdisciplinary field with flexible designs to accommodate and concentrate imaging and therapeutic payloads into pathological cells through selective binding to disease specific cell membrane biomarkers. This concept of personalized medicine reflects the vision of "magic bullets" proposed by German biochemist Paul Ehrlich over 100 years ago. As happening worldwide, Chinese scientists are contributing to this tsunami of science and technologies through impactful national programs and international research collaborations. This review provides a comprehensive update of Chinese innovations to address intractable unmet medical need in China and worldwide in the optical sciences. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Ghrelin protects against contact dermatitis and psoriasiform skin inflammation by antagonizing TNF-α/NF-κB signaling pathways

Contact dermatitis and psoriasis are skin disorders caused by immune dysregulation, yet much remains unknown about their underlying mechanisms. Ghrelin, a recently discovered novel peptide and potential endogenous anti-inflammatory factor expressed in the epidermis, is involved in skin repair and disease. In this study, we investigated the expression pattern and therapeutic effect of ghrelin in both contact dermatitis and psoriasis mouse models induced by oxazolone (OXA) and imiquimod (IMQ), respectively, and in TNF-α-stimulated RAW264.7 macrophages, NHEKs and skin fibroblasts. Ghrelin expression was reduced in both the OXA-induced contact dermatitis and IMQ-induced psoriasis mouse models. Furthermore, treatment with ghrelin attenuated skin inflammation in both the contact dermatitis and psoriasis mouse models. Mice administered PBS after OXA- or IMQ-induced model generation exhibited typical skin inflammation, whereas ghrelin treatment in these mouse models substantially decreased the dermatitis phenotype. In addition, exogenous ghrelin attenuated the inflammatory reaction induced by TNF-α in RAW264.7 cells. Moreover, ghrelin administration limited activation of NF-κB signaling. In summary, ghrelin may represent a potential molecular target for the prevention and treatment of inflammatory skin diseases, including contact dermatitis and psoriasis.

In vivo imaging the motility of monocyte/macrophage during inflammation in diabetic mice

Diabetes, as a chronic metabolic disease, can impair the immune function of monocytes/macrophages (MMs). However, it is unclear how MM immune response to inflammation with the development of diabetes, and whether immune response around the inflammatory foci depends on the depth in tissue. Footpad provides a classical physiological site for monitoring cellular behavior during inflammation, but limited to the superficial dermis due to the strong scattering of footpad. Herein, we used confocal microscopy to monitor the motility of MMs in deeper tissue around inflammatory foci with the development of type 1 diabetic (T1D) mice through a switchable footpad skin optical clearing window. Delayed-type hypersensitivity (DTH) model was elicited on the footpad of T1D. Results demonstrated that progressive T1D led to the gradually potentiated MM recruitment and increased expression of monocyte chemoattractant protein-1 during DTH, but MM migration displacement, motion velocity and motility coefficient were significantly attenuated. Besides, MMs from the deeper dermis had a much larger migration displacement than those from superficial dermis at early stages of DTH but an opposite tendency at late stages for non-T1D, while progressive T1D obscured this difference gradually. This study will be helpful for investigating the influences of progressive metabolic diseases on immune response. MM motion trajectory at depth of superficial dermis and the deeper dermis at AOVA (heat-aggregated ovalbumin)-4 hours and AOVA-72 hours on non-T1D (A) and T1D-4 weeks (B). Mean motility coefficient (C) at the 2 depths. Data were pooled from 6 mice per group. *P < .05 and **P < .01 compared among different T1D disease durations. #P < .05 compared between different depths.

Biophotonics in China

Biophotonics is a highly interdisciplinary field where physicists, chemists, biologists, physicians and engineers work together to solve the problems appearing in biology and medicine. In China, the Biophotonics discipline is often referred to as Biomedical Photonics, under the first-level disciplines Biomedical Engineering or Optical Engineering, and was initiated in the late 1990s. Over the past 20 years, biophotonics research in China expanded extraordinarily and has reached the frontiers of the world-level sciences. This white paper introduces the research groups in the biophotonics field in China, and their representative contributions.

FSOCA-induced switchable footpad skin optical clearing window for blood flow and cell imaging in vivo

The mouse footpad for its feature of hairlessness provides an available window for imaging vascular and cellular structure and function in vivo. Unfortunately, the strong scattering of its skin limits the penetration of light and reduces the imaging contrast and depth. Herein, an innovative footpad skin optical clearing agent (FSOCA) was developed to make the footpad skin transparent quickly by topical application. The results demonstrate that FSOCA treatment not only allowed the cutaneous blood vessels and blood flow distribution to be monitored by laser speckle contrast imaging technique with higher contrast, but also permitted the fluorescent cells to be imaged by laser scanning confocal microscopy with higher fluorescence signal intensity and larger imaging depth. In addition, the physiological saline-treatment could make the footpad skin recover to the initial turbid status, and reclearing would not induce any adverse effects on the distributions and morphologies of blood vessels and cells, which demonstrated a safe and switchable window for biomedical imaging. This switchable footpad skin optical clearing window will be significant for studying blood flow dynamics and cellular immune function in vivo in some vascular and immunological diseases. Picture: Repeated cell imaging in vivo before (a) and after (b) FSOCA treatment. (c) Merged images of 4 h (cyan border) or 72 h (magenta border) over 0 h. (d) Zoom of ROI in 4 h (yellow rectangle) or 72 h (red rectangle).

In Vivo Visualization of Tumor Antigen-containing Microparticles Generated in Fluorescent-protein-elicited Immunity

In vivo optical spatio-temporal imaging of the tumor microenvironment is useful to explain how tumor immunotherapies work. However, the lack of fluorescent antigens with strong immunogenicity makes it difficult to study the dynamics of how tumors are eliminated by any given immune response. Here, we develop an effective fluorescent model antigen based on the tetrameric far-red fluorescent protein KatushkaS158A (tfRFP), which elicits both humoral and cellular immunity. We use this fluorescent antigen to visualize the dynamic behavior of immunocytes as they attack and selectively eliminate tfRFP-expressing tumors in vivo; swarms of immunocytes rush toward tumors with high motility, clusters of immunocytes form quickly, and numerous antigen-antibody complexes in the form of tfRFP(+) microparticles are generated in the tumor areas and ingested by macrophages in the tumor microenvironment. Therefore, tfRFP, as both a model antigen and fluorescent reporter, is a useful tool to visualize specific immune responses in vivo.

Nonlinear optical microscopy for immunoimaging: a custom optimized system of high-speed, large-area, multicolor imaging

BACKGROUND

The nonlinear optical microscopy has become the current state-of-the-art for intravital imaging. Due to its advantages of high resolution, superior tissue penetration, lower photodamage and photobleaching, as well as intrinsic z-sectioning ability, this technology has been widely applied in immunoimaging for a decade. However, in terms of monitoring immune events in native physiological environment, the conventional nonlinear optical microscope system has to be optimized for live animal imaging. Generally speaking, three crucial capabilities are desired, including high-speed, large-area and multicolor imaging. Among numerous high-speed scanning mechanisms used in nonlinear optical imaging, polygon scanning is not only linearly but also dispersion-freely with high stability and tunable rotation speed, which can overcome disadvantages of multifocal scanning, resonant scanner and acousto-optical deflector (AOD). However, low frame rate, lacking large-area or multicolor imaging ability make current polygonbased nonlinear optical microscopes unable to meet the requirements of immune event monitoring.

METHODS

We built up a polygon-based nonlinear optical microscope system which was custom optimized for immunoimaging with high-speed, large-are and multicolor imaging abilities.

RESULTS

Firstly, we validated the imaging performance of the system by standard methods. Then, to demonstrate the ability to monitor immune events, migration of immunocytes observed by the system based on typical immunological models such as lymph node, footpad and dorsal skinfold chamber are shown. Finally, we take an outlook for the possible advance of related technologies such as sample stabilization and optical clearing for more stable and deeper intravital immunoimaging.

CONCLUSIONS

This study will be helpful for optimizing nonlinear optical microscope to obtain more comprehensive and accurate information of immune events.