Yoshito Kakihara

Background/Objectives: Regular physical exercise conditioning attenuates nociceptive responses. However, it remains unclear whether physical exercise performed before local inflammation exerts prolonged preventive effects. This study determined whether treadmill run (TR) preconditioning produces sustained preventive effects on craniofacial nociception and associated brain responses following persistent craniofacial inflammation. Methods: Male C57BL/6J mice were assigned to sedentary or TR groups. Daily TR conditioning was performed for 10 days before masseter muscle injection of complete Freund’s adjuvant (CFA) on Day 0. Craniofacial-pain- and related anxiety-like behaviors were determined by the orofacial formalin, elevated plus maze, and open-field tests before and 3 (CFA3) or 7 (CFA7) days after CFA injection. Brain responses in the amygdala, insular cortex, hippocampal CA1, and primary motor cortex were assessed using multiple epigenetic- and neural-activity-related markers. Results: Under sedentary conditions, both CFA3 and CFA7 groups showed increased pain- and anxiety-like behaviors and elevated expression of epigenetic- and neural-activity-related markers in most brain regions. TR preconditioning attenuated these behavioral responses even three and seven days after TR cessation and altered the expression of epigenetic markers in several brain regions, although the direction of change varied by region and time point. TR preconditioning consistently reduced the expression of neural activity markers in most brain areas in both the CFA3 and CFA7 groups, with a few exceptions. Conclusions: TR preconditioning exerted prolonged preventive effects on craniofacial-pain-like behaviors and associated brain responses following craniofacial inflammation.

Background/Objectives: With the aging of the population, the number of patients with osteoporosis is increasing worldwide. Osteoporosis results from an imbalance in bone remodeling by osteoblasts and osteoclasts. This study investigated the effects of sake lees and rice koji, traditional Japanese rice-fermented products, on bone metabolism. Methods: Both sake lees extract and rice koji extract increased alkaline phosphatase (ALP) activity, extracellular collagen accumulation, and mineralization of MC3T3-E1 cells. In addition, the intracellular protein levels of Hsp47 and Sec23IP, which are required for collagen maturation and secretion, respectively, were increased during the differentiation. On the other hand, both extracts significantly inhibited osteoclastic differentiation. Furthermore, the effects of freeze-dried sake lees or rice koji extract on osteoporotic bones were examined using twelve-week-old female C3H/HeJ ovariectomized (OVX) mice. Results: The groups of mice fed 20% or 40% freeze-dried sake lees showed significant suppression of the loss in bone volume fraction (BV/TV) and trabecular volume (Tb.V) compared with those fed a normal diet as well as the 40% freeze-dried sake lees-fed group reduced in the loss of trabecular thickness (Tb.Th). Similarly, the rice koji extract-treated mice showed significant inhibition of the loss in BV/TV, Tb.V, and even trabecular number (Tb.N.). Folic acid and S-adenosylmethionine (SAM), which have been reported to be present in sake lees, promoted extracellular collagen production by osteoblasts. Conclusions: In OVX mice, the intake of freeze-dried sake lees or rice koji extract was associated with the attenuation of trabecular bone loss, suggesting potential beneficial effects on bone metabolism.

Background/Objectives: Chronic craniofacial inflammation is recognized as a factor in anxiety-like behaviors, yet effective therapeutic options remain limited. Agmatine, a dietary bioactive compound found in fermented foods such as sake lees, exhibits modulatory effects on neural functions, alleviating psychological distress like anxiety associated with local inflammation. Methods: We investigated both the therapeutic and preventive effects of agmatine on anxiety-like behaviors and the related neural basis in a mouse model of persistent craniofacial inflammation induced by complete Freund’s adjuvant (CFA). Results: Comprehensive behavioral assessments, including the elevated plus maze, open field, dark–light box, social interaction, and novel object recognition tests, revealed that therapeutic agmatine administration (1.0 and 30 mg/kg) significantly reduced CFA-induced anxiety-like behaviors, with the higher dose showing more robust and sustained effects across multiple time points. These behavioral improvements were paralleled by reductions in acetylated histone H3, FosB, and c-Fos expression in key anxiety-related brain regions, suggesting a reversal of craniofacial inflammation-associated neural changes. In contrast, preventive agmatine treatment exerted modest and time-dependent behavioral benefits with minimal molecular normalization. Notably, preventive agmatine did not affect general locomotor activity (indicated by total movement distance), indicating that its anxiolytic effects were not confounded by altered locomotor activity. Metabolomic analysis confirmed the presence of agmatine in sake lees (~0.37 mM), supporting the hypothesis that fermented food products might offer dietary routes to emotional resilience. Conclusions: These findings underscore agmatine’s promise as a context-specific epigenetic modulator capable of mitigating anxiety-like behaviors by normalizing inflammation-driven molecular dysregulation in the brain.

This narrative review provides an overview of current knowledge on the impact of nutritional strategies on chronic craniofacial pain associated with temporomandibular disorders (TMDs). Individuals experiencing painful TMDs alter their dietary habits, avoiding certain foods, possibly due to chewing difficulties, which might lead to nutrient deficiencies. Our literature investigation revealed that the causal links between nutritional changes and craniofacial pain remain unclear. However, clinical and preclinical studies suggest that nutraceuticals, including vitamins, minerals, polyphenols, omega-3 fatty acids, isoprenoids, carotenoids, lectins, polysaccharides, glucosamines, and palmitoylethanolamides, could have beneficial effects on managing TMDs. This is described in 12 clinical and 38 preclinical articles since 2000. Clinical articles discussed the roles of vitamins, minerals, glucosamine, and palmitoylethanolamides. The other nutraceuticals were assessed solely in preclinical studies, using TMD models, mostly craniofacial inflammatory rodents, with 36 of the 38 articles published since 2013. Our investigation indicates that current evidence is insufficient to assess the efficacy of these nutraceuticals. However, the existing data suggest potential for therapeutic intervention in TMDs. Further support from longitudinal and randomized controlled studies and well-designed preclinical investigations is necessary to evaluate the efficacy of each nutraceutical intervention and understand their underlying mechanisms in TMDs.

This study determined the effect of daily administration of Rice-koji on anxiety and nociception in mice subjected to repeated forced swim stress (FST). In a parallel experiment, it was determined whether ergothioneine (EGT) contained in Rice-koji displayed similar effects. Anxiety and nociception were assessed behaviorally using multiple procedures. c-Fos and FosB immunoreactivities were quantified to assess the effect of both treatments on neural responses in the paraventricular nucleus of the hypothalamus (PVN), nucleus raphe magnus (NRM), and lumbar spinal dorsal horn (DH). FST increased anxiety- and pain-like behaviors in the hindpaw. Rice-koji or EGT significantly prevented these behaviors after FST. In the absence of formalin, both treatments prevented decreased FosB expressions in the PVN after FST, while no effect was seen in the NRM and DH. In the presence of formalin, both treatments prevented changes in c-Fos and FosB expressions in all areas in FST mice. Further, in vitro experiments using SH-SY5Y cells were conducted. Rice-koji and EGT did not affect cell viability but changed the level of brain-derived neurotrophic factor. In conclusion, Rice-koji could reduce anxiety and pain associated with psychophysical stress, possibly mediated by the modulatory effects of EGT on neural functions in the brain.

The conditions of stress contagion are induced in bystanders without direct experiences of stressful events. This study determined the effects of stress contagion on masseter muscle nociception in mice. Stress contagion was developed in the bystanders after cohabitating with a conspecific mouse subjected to social defeat stress for 10 days. On Day 11, stress contagion increased anxiety‐ and orofacial inflammatory pain‐like behaviors. The c‐Fos and FosB immunoreactivities evoked by masseter muscle stimulation were increased in the upper cervical spinal cord, while c‐Fos expressions were increased in the rostral ventromedial medulla, including the lateral paragigantocellular reticular nucleus and nucleus raphe magnus in stress contagion mice. The level of serotonin in the rostral ventromedial medulla was increased under stress contagion, while the number of serotonin positive cells was increased in the lateral paragigantocellular reticular nucleus. Stress contagion increased c‐Fos and FosB expressions in the anterior cingulate cortex and insular cortex, both of which were positively correlated with orofacial inflammatory pain‐like behaviors. The level of brain‐derived neurotrophic factor was increased in the insular cortex under stress contagion. These results indicate that stress contagion can cause neural changes in the brain, resulting in increased masseter muscle nociception, as seen in social defeat stress mice.

Tissue-specific stem cells exist in tissues and organs, such as skin and bone marrow. However, their pluripotency is limited compared to embryonic stem cells. Culturing primary cells on plastic tissue culture dishes can result in the loss of multipotency, because of the inability of tissue-specific stem cells to survive in feeder-less dishes. Recent findings suggest that culturing primary cells in medium containing feeder cells, particularly genetically modified feeder cells expressing growth factors, may be beneficial for their survival and proliferation. Therefore, the aim of this study was to elucidate the role of genetically modified human feeder cells expressing growth factors in maintaining the integrity of primary cultured human deciduous dental pulp cells. Feeder cells expressing leukemia inhibitory factor, bone morphogenetic protein 4, and basic fibroblast growth factor were successfully engineered, as evidenced by PCR. Co-culturing with mitomycin-C-treated feeder cells enhanced the proliferation of newly isolated human deciduous dental pulp cells, promoted their differentiation into adipocytes and neurons, and maintained their stemness properties. Our findings suggest that genetically modified human feeder cells may be used to maintain the integrity of primary cultured human deciduous dental pulp cells.

This study was designed to investigate the effects of Sake Lees extracts (SLE, Sake Kasu) on the functional activity of odontoblastic cells and tooth pulp of the rats. For in vitro studies, a rat clonal odontoblast-like cell line, KN-3 cells were cultured. SLE significantly decreased KN-3 cell proliferation, but showed no significant cytotoxicity. SLE effects on several protein productions of KN-3 cells were compared with PBS. SLE and PBS increased alkaline phosphatase (ALP), dentin sialoprotein (DSP), and osterix in a day-course dependent manner, while SLE increased the induction of ALP on day 9–21 and DSP on day 15–21. SLE also increased Runx2 expression on day 3 and 9 compared to PBS. Alizarin Red stainings revealed that SLE showed a subtle increase in mineralization of KN-3 cells on day 15 and 21. A histological investigation was conducted to assess if SLE induced reparative dentin formation after direct capping at the exposed tooth pulp in rats, suggesting that SLE could increase the reparative dentin formation more than PBS. These findings suggest that Sake Lees could have functional roles in the alterations of odontoblastic activity, which might influence the physiology of the tooth pulp.