Lymph nodes (LNs) are critical components of anti-cancer immune responses, orchestrating antigen presentation to T-cells. Aging impairs immune function, but its impact on regional LNs in cancer remains poorly understood. This study investigated age-related morphological and immunological changes in mesenteric LNs and their association with the immune microenvironment in colorectal cancer (CRC). A total of 160 patients who underwent curative resection for CRC were retrospectively analyzed. LN ectasia, defined as sinusoidal dilation accompanied by a reduction in LN sinus macrophages, was evaluated histologically. LN ectasia was significantly more frequent in elderly patients and in right-sided colon cancers. Patients with pronounced LN ectasia showed reduced serum albumin and leukocyte counts. Immunohistochemical analysis revealed that marked LN ectasia was associated with decreased infiltration of CD8+ T cells and Iba1+/CD163+ tumor-associated macrophages in the primary cancer lesion, consistent with a “cold” immune microenvironment. Although LN ectasia was not directly associated with prognosis, it reflected systemic immunosenescence and attenuated local immune activation. These findings suggest that LN ectasia serves as a histological marker of aging-related LN dysfunction, contributing to diminished anti-cancer immunity in CRC.

After a crush injury in sciatic nerve fibers, dynamic changes in blood circulation and immune-cell mobilization occur during axonal regeneration. High-resolution visualization under near-physiological conditions is crucial for understanding these mechanisms. Conventional histological techniques introduce perfusion- and dehydration-induced artifacts that obscure circulation. We employed the in vivo cryotechnique (IVCT) to visualize blood flow within sciatic nerve fibers and assess temporal changes during regeneration. In uninjured mice, IVCT preserved native tissue architecture with minimal shrinkage compared to perfusion fixation, with superiority quantitatively shown by fractal analysis. In the crush model, hematoxylin-eosin, Luxol fast blue, and immunohistochemical staining of IVCT-prepared, freeze-substituted sections revealed axonal degeneration and regrowth. The close association between regenerating fibers and vascular structures, along with erythrocyte distribution, indicates a morphological link between nerves and blood vessels. Electrophysiological assessment using compound muscle action potentials and functional recovery measured by the sciatic functional index demonstrated restored nerve function at 28 days, consistent with histology. These findings suggest that IVCT is a useful method for analyzing peripheral nerve regeneration and vascular dynamics, thereby highlighting its potential as a novel approach in peripheral nerve research.

Periodontitis is a chronic inflammatory disease characterized by collagen degradation and alveolar bone loss. Although estrogen contributes to periodontal homeostasis, the role of the membrane-bound G protein–coupled estrogen receptor 30 (GPR30) in periodontitis remains unclear. This study investigated the temporal involvement of GPR30 in ligature-induced periodontitis, focusing on alveolar bone changes, collagen integrity, fibroblast activation, and epigenetic regulation. Twenty male Wistar rats were allocated to control and periodontitis groups and evaluated at days 7, 14, and 21 following placements of a stainless-steel ligature around the maxillary first molars. Alveolar bone loss was assessed radiographically, while inflammatory changes and collagen organization were examined using hematoxylin–eosin and Masson’s trichrome staining. Immunohistochemistry was performed to evaluate GPR30, collagen I/III, α-smooth muscle actin (α-SMA), and histone modifications. Statistical analysis was conducted using one-way ANOVA with Tukey’s post hoc test. Alveolar bone loss and collagen degradation were detectable on day 7 and peaked at day 14. GPR30 expression increased during the active inflammatory phase, accompanied by elevated α-SMA and histone H4 lysine 8 crotonylation (H4K8cr), and declined by day 21. Fibroblast transiently adopted a myofibroblast phenotype during inflammation and regressed during early tissue repair. Temporal changes in H4K8cr closely paralleled GPR30 expression. These findings indicate that GPR30 is dynamically associated with inflammatory and remodeling phases of periodontitis and may contribute to epigenetic regulation during periodontal tissue remodeling.

Microscopy with ultraviolet surface excitation (MUSE) enables rapid fluorescence imaging of tissue surfaces, but MUSE images differ markedly from conventional hematoxylin and eosin images, making cancer delineation challenging for routine pathological practice. We investigated the feasibility of deep learning-based semantic segmentation, which assigns a class label to each pixel, for pixel-wise breast cancer detection in MUSE images. Fresh breast tissues from 30 mastectomy patients with breast cancer were stained with terbium and Hoechst and imaged by MUSE. A total of 150 cancerous images (five per case) were manually annotated into cancerous and non-cancerous classes, and 300 non-cancerous images (ten per case) were collected. Models were trained and evaluated using five-fold nested cross-validation, comparing a cancer-only (CO) model trained solely on cancerous images with a cancer plus non-cancer (CN) model trained on both cancerous and non-cancerous images. The CO model achieved a higher Dice score than the CN model (CO, 0.7478; CN, 0.7343). Sliding window-based majority voting post-processing reduced scattered false-positive areas and improved Dice scores (CO, 0.7984; CN, 0.7849). These results support the feasibility of deep learning-based semantic segmentation for visualizing breast cancer regions and provide a basis for future quantitative applications using MUSE images.