Chiharu Ohira

Background/Objectives: In this study, we focused on a mixed microbial culture of Lactobacillus paracasei, Pichia membranifaciens, and Saccharomyces cerevisiae (LS) as a new probiotic and examined the therapeutic and preventive effects of topical treatment with LS in a mouse model of atopic dermatitis (AD). Methods: Immunomodulatory effects of LS were examined with murine dendritic cell lines (DC2.4) by measuring the interleukin (IL)-10 and tumor necrosis factor (TNF) α levels. The anti-inflammatory effects of LS were evaluated in stimulated human epidermal keratinocytes (HaCaTs) by focusing on the production of IL-8 and thymus and activation-regulated chemokine (TARC). Therapeutic and preventive properties of topical treatment with LS (10%) were finally examined in a mouse model of AD developed by topical sensitization to house dust mite ointment. Clinical symptoms, back skin thickness, and transepidermal water loss (TEWL) were monitored weekly, and the immune responses in the auricular lymph nodes were analyzed after necropsy. Results: LS treatment significantly enhanced the secretions of IL-10 and TNFα by DC2.4 cells. IL-8 and TARC production by stimulated HaCaT cells was significantly decreased by co-culturing with LS. Although there were no significant changes in clinical symptoms, skin thickness, or TEWL in the therapeutic setting of the AD mouse model, the number of IgE-positive B cells and IL-4 levels in the local lymph nodes significantly decreased in the LS treatment group. Preventive treatment with LS significantly decreased AD symptoms compared to those in AD control mice. Conclusions: Our findings indicate that the immunomodulatory and anti-inflammatory effects of LS prevent the development of AD.

Ashitaba (Angelica keiskei) is a perennial herb native to Japan, traditionally consumed as a health-promoting food and herbal medicine. This study evaluated the antimicrobial, anti-halitosis, and anti-inflammatory effects of Ashitaba extract on canine periodontal disease (PD) caused by Porphyromonas gulae (P. gulae). In vitro, Ashitaba extract (0.006–0.1%) significantly inhibited P. gulae viability by up to 80% and reduced biofilm formation by approximately 10% at 0.1%. The extract also suppressed the production of volatile sulfur compounds—hydrogen sulfide and methyl mercaptan—by over 80% and 40%, respectively, within 10 min. Furthermore, Ashitaba extract markedly decreased P. gulae-induced pro-inflammatory cytokine secretion (IL-1β, IL-6, TNF-α) by up to 90% in murine, canine, and human macrophage and gingival cell lines. In vivo, daily oral application of 0.05% Ashitaba-extract gel for four weeks, with or without tooth brushing, significantly improved gingivitis scores (by 40–60%), reduced halitosis levels, and decreased P. gulae DNA detection and enzymatic activity in dogs with PD. These findings demonstrate that Ashitaba extract possesses potent bactericidal, anti-halitosis, and anti-inflammatory properties, supporting its potential as a natural adjunctive therapy for the prevention and management of canine periodontal disease.

Background/Objectives: In this study, we focused on a mixed microbial culture of Lacto-bacillus paracasei, Pichia membranifaciens and Saccharomyces cerevisiae (LS) as a new probiotic and examined the therapeutic and preventive effects of dermal treatment with LS in a mouse model of atopic dermatitis (AD). Methods: Immunomodulatory effects of LS were examined with murine dendritic cell lines (DC2.4) by measuring the interleukin (IL)-10 and tumor necrosis factor (TNF) α levels. The anti-inflammatory effects of LS were evalu-ated in stimulated human epidermal keratinocytes (HaCaTs) by focusing on the produc-tion of IL-8 and thymus and activation-regulated chemokine (TARC). Therapeutic and preventive properties of topical treatment with LS (10%) were finally examined in a mouse model of AD developed by topical sensitization to house dust mite ointment. Clinical symptoms, back skin thickness, and transepidermal water loss (TEWL) were monitored weekly, and the immune responses in the auricular lymph nodes were analyzed after necropsy. Results: LS treatment significantly enhanced the secretions of IL-10 and TNFα by DC2.4 cells. IL-8 and TARC production by stimulated HaCaT cells was significantly decreased by co-culturing with LS. Although there were no significant changes in clinical symptoms, skin thickness, or TEWL in the therapeutic setting of AD mouse model, the number of IgE-positive B cells and IL-4 levels in the local lymph nodes significantly de-creased in the LS treatment group. Preventive treatment with LS significantly decreased AD symptoms compared to those in AD control mice. Conclusions: Our findings indicate that the immunomodulatory and anti-inflammatory effects of LS prevent the development of AD.

Mycotoxins are synthesized by various fungal species and are known to exert toxic effects on vertebrates and other animals, even at low concentrations. However, the current countermeasure for mycotoxin contamination is random inspection of samples prior to shipment. In this study, we focused on Chlorella sorokiniana (CS) from Ishigaki Island, Japan, and examined its ability to detoxify deoxynivalenol (DON), ochratoxin A (OTA), and fumonisin B1 (FB1) in vitro and in vivo. The binding of CS to DON, OTA, and FB1 was evaluated in vitro. The detoxification of CS was demonstrated by monitoring its concentrations in the plasma and urine samples of male ICR mice. Plasma and urine samples were collected 30 min, 2 h, and 24 h after an oral administration of 5 mg/kg mycotoxins and/or 500 mg/kg CS. CS bound to more than 80% and 40% of DON and OTA, respectively, whereas the binding of CS to FB1 was less than 10%. The concentrations of DON and OTA in plasma and urine samples were substantially reduced by CS co-administration, whereas CS did not affect FB1 absorption. The co-administration of CS substantially inhibited the systemic absorption of DON and OTA.

Deoxynivalenol (DON) is a mycotoxin commonly found worldwide and is implicated in various health effects. We recently demonstrated that subacute oral exposure to DON significantly exacerbates symptoms of type 2 helper T-cell-mediated allergic diseases in a model. We aim to investigate the role of oral DON exposure in type 17 helper T-cell-mediated immunoreactive diseases using a mouse psoriasis model. Psoriasis was induced by the dermal administration of 5% imiquimod in female BALB/c mice. A standard rodent diet was supplemented with DON to achieve a final concentration of 0.3 ppm (1.5 μg/kg bw/day), which was administered daily for 14 days. Skin thickness, scratching behavior, and transepidermal water loss (TEWL) were continuously measured during imiquimod administration. Mice exposed to DON exhibited significant increases in skin thickness, TEWL, and scratching behavior. Histological evaluations revealed aggravated hyperplasia, neutrophil infiltration, and inflammatory cell accumulation in the dermis. Furthermore, DON exposure significantly increased the number of CD4+ helper T cells and CD11c+ MHC class II+ dendritic cells in the auricular lymph nodes, along with elevated TNF-α and IL-17 levels in stimulated T cells. The gene expression of IL-17 in skin tissue was also significantly up-regulated in DON-treated mice. Collectively, these findings suggest that oral exposure to DON aggravates symptoms in a mouse psoriasis model.