Publications by authors named "Keisuke Okabe"

Photoacoustic imaging (PAI) can evaluate lymphatic vessels with a high resolution (0.2 mm) compared with other methods. LUB0, a new PAI device that is smaller than the PAI-05 used since 2020 (both from Luxonus, Inc.

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Mammalian wounds leave visible scars, and there are no methods for complete regeneration. However, mouse fetuses regenerate their skin, including epidermal and dermal structures, up to embryonic day (E)13. This regeneration pattern requires the formation of actin cables in the wound margin epithelium; however, the molecular mechanisms are not fully understood.

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Background And Objectives: Lymphaticovenular anastomosis (LVA) is a surgical technique used to alleviate lymphedema by bypassing the lymphatic and venous vessels and facilitating lymphatic fluid drainage. Accurate evaluation of anastomotic patency is crucial for assessing LVA outcomes. Traditional near-infrared fluorescence lymphography has limitations, including fluorescence diffusion in subcutaneous fat and difficulty evaluating areas beneath the dermal backflow.

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Article Synopsis
  • - This study focused on how different cells in fetal mouse skin interact in 3D during regeneration, particularly looking at cell relationships and the role of tunneling nanotubes (TNTs) on embryonic days 13 and 15.
  • - Researchers performed skin incisions on the embryos and used advanced imaging techniques to observe the wound healing process, finding that epidermal keratinocytes worked closely with fibroblasts and macrophages for skin regrowth, especially at E13.
  • - They discovered that TNTs were present at the wound sites and played a crucial role in regeneration, but inhibiting their formation with cytochalasin B negatively affected healing, highlighting the importance of these cellular interactions.
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Wounds that occur in adults form scars due to fibrosis, whereas those in embryos regenerate. If wound healing in embryos is mimicked in adults, scarring can be reduced. We found that mouse fetuses could regenerate tissues up to embryonic day (E) 13, but visible scars remained thereafter.

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Unlike adult mammalian wounds, early embryonic mouse skin wounds completely regenerate and heal without scars. Analysis of the underlying molecular mechanism will provide insights into scarless wound healing. Twist2 is an important regulator of hair follicle formation and biological patterning; however, it is unclear whether it plays a role in skin or skin appendage regeneration.

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Background: Identification of the proper lymphatics is important for successful lymphaticovenular anastomosis (LVA) for lymphedema; however, visualization of lymphatic vessels is challenging. Photoacoustic lymphangiography (PAL) can help visualize lymphatics more clearly than other modalities. Therefore, we investigated the usefulness of PAL and determined whether the clear and three-dimensional image of PAL affects LVA outcomes.

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Mammalian skin, including human and mouse skin, does not regenerate completely after injury; it is repaired, leaving a scar. However, it is known that skin wounds up to a certain stage of embryonic development can regenerate. The mechanism behind the transition from regeneration to scar formation is not fully understood.

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Unlike adults, early developing fetuses can completely regenerate tissue, and replicating this could lead to the development of treatments to reduce scarring. Mice epidermal structures, including wound healing patterns, are regenerated until embryonic day (E) 13, leaving visible scars thereafter. These patterns require actin cable formation at the epithelial wound margin through AMP-activated protein kinase (AMPK) activation.

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Article Synopsis
  • Wounds on embryonic mouse fetuses can regenerate well until embryonic day (E) 13, after which they leave a permanent scar, suggesting a loss in regenerative capability.
  • The study investigated the role of sonic hedgehog (Shh), a protein important in embryonic development, in skin regeneration by examining its expression and effects in injured mouse embryos and adult mice.
  • Results indicated that while Shh expression remains stable at E13, it increases after E14 and negatively impacts skin texture regeneration, highlighting its crucial role in keratinocyte behavior during wound healing.
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Muscle regeneration requires the coordination of muscle stem cells, mesenchymal fibro-adipogenic progenitors (FAPs), and macrophages. How macrophages regulate the paracrine secretion of FAPs during the recovery process remains elusive. Herein, we systemically investigated the communication between CD206 M2-like macrophages and FAPs during the recovery process using a transgenic mouse model.

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Unlabelled: The dermal panniculus carnosus (PC) muscle is critical for wound contraction in lower mammals and is a useful model of muscle regeneration owing to its high cellular metabolic turnover. During wound healing in mice, skin structures, including PC, are completely regenerated up to embryonic day (E) 13, but PC is only partially regenerated in fetuses or adult animals after E14. Nevertheless, the mechanisms underlying wound repair for complete regeneration in PC have not been fully elucidated.

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Up to a certain developmental stage, a fetus can completely regenerate wounds in the skin. To clarify the mechanism of fetal skin regeneration, identifying when the skin switches from fetal-type wound regeneration to adult-type wound repair is necessary. We hypothesized that this switch occurs at several time points and that complete skin regeneration requires epidermal-dermal interactions and the formation of actin cables.

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Mast cells and inflammatory cells are abundant in keloid and hypertrophic scar tissues. Even if the cause of physical injury is similar, such as piercing or scratching with hands, clinical findings show differences in the size of keloids in the same area. Hence, we performed histological studies on giant keloids larger than the earlobe, and other smaller keloids.

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Article Synopsis
  • Mice embryos have a unique ability to heal wounds without scars up to embryonic day 13 (E13), but this ability decreases after E17, leading to scar formation.
  • The protein Lhx2 plays a crucial role in managing hair follicle stem cells during this healing process, with its expression increasing after E13.
  • When Lhx2 was knocked down in embryos at E15, wound healing was significantly delayed and scars became more prominent, indicating its importance in both cell division related to healing and the development of scars.
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Wnt proteins secrete glycoproteins that are involved in various cellular processes to maintain homeostasis during development and adulthood. However, the expression and role of Wnt in wound healing have not been fully documented. Our previous studies have shown that, in an early-stage mouse fetus, no scarring occurred after cutaneous wounding, and complete regeneration was achieved.

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Adult mammalian wounds leave visible scars, whereas skin wounds in developing mouse fetuses are scarless until a certain point in development when complete regeneration occurs, including the structure of the dermis and skin appendages. Analysis of the molecular mechanisms at this transition will provide clues for achieving scarless wound healing. The fibroblast growth factor (FGF) family is a key regulator of inflammation and fibrosis during wound healing.

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Nicotinamide mononucleotide (NNM) is an orally bioavailable NAD precursor that has demonstrated beneficial effects against aging and aging-associated diseases in animal models. NMN is ultimately converted to NAD, a redox cofactor that mediates many metabolic enzymes. NAD also serves as the substrate for poly(ADP-ribose) polymerase (PARP) and sirtuins, and regulates various biological processes, such as metabolism, DNA repair, gene expression, and stress responses.

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Background: Variations in skin healing capacities are observed during different murine embryonic developmental stages. Through embryonic day 16 (E16), embryos are able to regenerate dermal architecture following flank skin wounding; however, after E17, wounds heal incompletely, inducing scar formation. The regenerative ability of the E16 fetal dermis depends on the migration of dermal mesenchymal cells.

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Background: Dermal backflow (DBF), which refers to lymphatic reflux due to lymphatic valve insufficiency, is a diagnostic finding in lymphedema. However, the three-dimensional structure of DBF remains unknown. Photoacoustic lymphangiography (PAL) is a new technique that enables the visualization of the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and can provide three-dimensional images of superficial lymphatic vessels and the venous system.

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Lymphaticovenular anastomosis (LVA) is a widely performed surgical procedure for the treatment of lymphedema. For good LVA outcomes, identifying lymphatic vessels and venules is crucial. Photoacoustic lymphangiography (PAL) is a new technology for visualizing lymphatic vessels.

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Recently, obesity-induced insulin resistance, type 2 diabetes, and cardiovascular disease have become major social problems. We have previously shown that Astaxanthin (AX), which is a natural antioxidant, significantly ameliorates obesity-induced glucose intolerance and insulin resistance. It is well known that AX is a strong lipophilic antioxidant and has been shown to be beneficial for acute inflammation.

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Background:  Lymphatic vessels are difficult to identify using existing modalities as because of their small diameter and the transparency of the lymph fluid flowing through them.

Methods:  Here, we introduce photoacoustic lymphangiography (PAL), a new modality widely used for lymphedema treatment, to observe limb lymphatic vessels. The photoacoustic imaging system used in this study can simultaneously visualize lymphatic vessels and veins with a high resolution (0.

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Background: Lymphaticovenular anastomosis (LVA) is a minimally invasive surgical procedure used to treat lymphedema. Volumetric measurements and quality-of-life assessments are often performed to assess the effectiveness of LVA, but there is no method that provides information regarding postoperative morphological changes in lymphatic vessels and veins after LVA. Photoacoustic lymphangiography (PAL) is an optical imaging technique that visualizes the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and provides three-dimensional images of superficial lymphatic vessels and the venous system simultaneously.

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Background: Cultured epidermal transplantation (JACE) is performed for giant congenital melanocytic nevus (GCMN), but there are few reports on its postoperative course and surgical content or indications. We aimed to investigate the postoperative course of GCMN patients undergoing cultured epidermal autograft transplantation and compare the outcomes between 2 nevus tissue resection methods.

Methods: Twelve GCMN patients aged 0 months to 8 years and 9 months were included in this single-center case series study.

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