Ken Kobayashi

Garlic is utilized as a feed additive in livestock production. The pungent and spicy flavor of garlic is attributed to allicin, which functions as an agonist of the Ca ²⁺ channel TRPA1. Although mammary epithelial cells (MECs) express TRPA1, the physiological role remains largely unexplored. During lactation, MECs produce milk components and maintain the blood–milk barrier by forming tight junctions (TJs). In this study, we investigated whether allicin regulates milk production and TJs in mouse MECs via TRPA1. Allicin inhibited casein production and strengthened the TJ barrier integrity by recruiting claudin‐3 to the TJ region. Allicin induced TRPA1‐mediated Ca ²⁺ influx and inactivated STAT5 and Akt/mTOR signaling. Similarly, other TRPA1 agonists, allyl isothiocyanate (found in wasabi) and cinnamaldehyde (cinnamon), downregulated casein production and STAT5 inactivation. Notably, TRPA1 in MECs was expressed on the apical membrane in contact with milk, whereas its localization on the basolateral membrane could not be confirmed in this study. These findings suggest that the enhancement of TJ barrier integrity in MECs is a key physiological response to allicin that is mediated, at least in part, through TRPA1 localized to the apical membrane and accompanied by a concomitant reduction in milk production.

Osmotic and hydrostatic (intramammary pressure) pressures within the mammary gland may stimulate mammary epithelial cells and leukocytes, which alter milk production and immune functions. We aimed to clarify the effects of different volumes and concentrations of NaCl solution on milk and antimicrobial substance production in lactating goats. Intramammary infusions of different NaCl solution concentrations (0.9% and 2.7%) at different volumes (50 mL or until full in the udder) were carried out; milk samples were collected for 5 days after infusion. The infusions resulted in significant daily effects on milk yield, somatic cell count (SCC), sodium ion (Na ⁺ ) and potassium ion (K ⁺ ), milk amyloid A (MAA), S100A7, and lactoferrin (LF) concentrations. Sodium and potassium ions, SCC, and MAA levels differed depending on the infused volume, whereas those of S100A7 and LF differed according to the NaCl concentration. These results suggest that short‐term increases in hydrostatic and osmotic pressures modulate milk production and stimulate antimicrobial factor production in the mammary glands. Hence, they highlight a potential approach toward enhancing innate immune function in the udder.

Royal jelly (RJ), a honeybee product, is used as a cosmetic and food ingredient to improve skin condition. However, the influences of RJ on hair growth remain unclear. In this study, we investigated whether RJ regulates hair follicle development, hair shaft formation, and proliferation of hair follicle stem cells (HFSCs) using a gentle anagen induction model by shaving the back skin and a forced anagen induction model by depilating the back skin in mice. The results showed that topical application of RJ on depilated skin induced thinning of the hair shaft and smaller hair bulb formation during the anagen phase. In addition, RJ suppressed the proliferation of CK15-positive HFSCs in hair follicles at the early and middle anagen stages of shaved back skin. RJ suppressed the proliferation of cultured HFSCs in vitro. These findings suggested that RJ induces the formation of thin hair shafts by suppressing the HFSC proliferation.

Foreign body reactions (FBRs) are inadvertently observed in invading or artificially embedded materials, triggering inflammation and subsequent fibrotic processes to occur in situ. Here, we assessed the spatiotemporal formation of connective tissue around implanted materials to establish a technique using connective tissue formed by FBRs as xenografts. An acrylic resin implant, comprising a columnar inner rod and a tubular outer cylinder (OC) with several slits, was embedded in adult dairy cows. Tissues formed in the inner rod and OC groups were histologically analyzed at weeks 2, 4, 8, and 12. Edematous tissues with non-collagenous fibers formed for 2 weeks and showed increased cellularity after 4 weeks. The weight, thickness, amounts of total protein, collagen, DNA, and quantitative scores of α-smooth muscle actin-positive myofibroblasts or elastic fibers notably increased after 8 weeks, with condensed collagen fibers showing orientation. Inflammatory cells were primarily localized in tissues close to the OC, and their numbers increased, with the count of CD204+ cells peaking at 8 weeks and declining at 12 weeks. The count of Ki67+ proliferating cells slightly increased in tissues close to the OC; however, the number and lumen of CD31+ vessels increased. These results may help understand FBR-related tissue remodeling.