Evaluation of oral care using MA-T gel for high-risk patients: a pilot study.

BACKGROUND: Oral care with gel is a common method for preventing aspiration in high-risk patients. An oral care gel is used to clean and moisturize the oral cavity. However, the effects of gel care on the oral bacteria remain unclear. In this pilot study, we described a matching transformation system (MA-T) for elderly high-risk patients. MA-T is an on-demand aqueous chlorine dioxide solution that provides excellent safety and has various antimicrobial activities, even in the presence of abundant organic compounds. This study investigated the effects of MA-T gel in patients requiring nursing care. MATERIALS AND METHODS: Patients who were hospitalized for nursing care were included in this study. No drugs and foods were administered orally. Oral bacteria and intraoral humidity were examined by daily care using MA-T gel. Moreover, oral membranous substances were analyzed and material from the oral cavity was cultured on selective media for identifying opportunistic organisms. RESULTS: Membranous substances were present in the oral cavities of all patients. The number of bacteria decreased, and oral moisture improved, after treatment with MA-T gel. Moreover, oral humidity was also controlled with the continued use of MA-T gel. MA-T gels should be used not only for professional care but also on a daily basis for better oral care. Furthermore, the results of bacterial cultures showed that MA-T controls the propagation of opportunistic bacterial infections. CONCLUSION: Membranous substances may be observed in the oral cavity of individuals requiring nursing care for tube feeding. The results of this pilot study suggest that MA-T, a novel disinfectant, can be used for oral care in the elderly to reduce the risk of aspiration-pneumonia.

HIF-1α regulates mTOR signaling pathway during salivary gland development.

The mammalian target of rapamycin (mTOR)-composed of multiple complexes, including mTOR complex 1/2 (mTORC1/2)-is a serine-threonine kinase that regulates embryonic development. The transcription factor, hypoxia-inducible factor-1α (HIF-1α), is also involved in embryonic development. As the relationship between mTOR and HIF-1α during embryonic development remains unclear, we investigated the relationship between the two using ex vivo submandibular salivary gland organ cultures. When the expression of HIF-1α increased under hypoxic conditions (1% O2), the expression of mTOR signaling pathway-related proteins decreased. Conversely, when the expression of HIF-1α decreased, the expression of mTOR signaling pathway-related proteins increased. These results indicate a strong relationship between HIF-1α and the mTOR signaling pathway. For the first time, we clarified that HIF-1α negatively regulates the mTOR signaling pathway and suppresses salivary gland development under 1% O2 using small molecules. Our research provides new insights into the relationship between HIF-1α and the mTOR signaling pathway in embryonic organ development.

The HIF-1α pathway plays a critical role in salivary gland development in ex vivo organ cultures.

The transcription factor, hypoxia-inducible factor-1α (HIF-1α), has previously been shown to upregulate the expression of hypoxia-related genes, including erythropoietin (EPO). However, the role of hypoxia-inducible factor-1α in morphogenesis during salivary gland development is unclear. We investigated the function of HIF-1α in submandibular gland (SMG) organ cultures obtained from embryonic day 13.5 embryos from ICR female mice. Expression of HIF-1α, glucose transporter 1, and vascular endothelial growth factor was induced under hypoxia (5% O2 ). We further showed that BAY 87-2243-mediated inhibition of HIF-1α suppressed salivary gland development. Under severe hypoxia (1% O2 ), HIF-1α did not promote salivary gland development; this was due to suppression of cell proliferation and inhibition of the cell cycle and not because of autophagy and apoptosis. Additionally, using the inhibitor U0126, we verified that the ERK1/2 pathway is upstream of HIF-1α. Overall, we found that the HIF-1α signaling pathway plays a critical role in salivary gland development in ex vivo SMG organ cultures.

ΔNp63 is upregulated during salivary gland regeneration following duct ligation and irradiation in mice.

The transcription factor p63, a component of the p53 family, has important functions in development, homeostasis, and regeneration of epithelial tissues. However, the role of p63 in the regeneration of exocrine glands, including the salivary glands (SGs), has not been fully investigated. We investigated p63 expression in SG regeneration induced by duct ligation and irradiation. The expression of ΔNp63, a p63 isoform, increased and was colocalized with keratin 5 positive cells were myoepithelial cells. Furthermore, ΔNp63 expression was regulated by FGF7 stimulation via p38 MAPK phosphorylation and affected SG morphogenesis. These results suggest that ΔNp63 is essential for SG regeneration and may be a new target for regenerative treatment.