Regulation of IGF-I by IGFBP3 and IGFBP5 during odontoblast differentiation in mice

ObjectivesAlthough intracellular signaling pathways of insulin-like growth factor I (IGF-I) related to the proliferation of dental pulp cells have been investigated, the switching mechanism from cell proliferation to differentiation during odontogenesis remains elusive. This study aimed to elucidate the role of IGF binding protein (IGFBP) 3 and 5 in regulation of IGF-I during odontoblast differentiation in mouse incisors.MethodsThe detailed expression patterns of IGF-I, IGF-I receptor (IGF-IR), IGFBP3, and IGFBP5 together with that of an odontoblast differentiation marker, nestin, were examined by immunohistochemistry and/or in situ hybridization using paraffinized sections of TetOP-H2B-GFP mouse incisors at postnatal 4 weeks.ResultsUndifferentiated dental papilla cells and preodontoblasts (preOB) showed intense IGF-I- and IGF-IRα-positive reactions, and the expression was observed in differentiated odontoblasts, such as immature odontoblasts (iOB) and mature odontoblasts (mOB). IGFBP3/Igfbp3 was transiently expressed in preOB and early iOB, and the intensity of expression gradually reduced with the progression of odontoblast differentiation. In contrast, immunohistochemical analysis for IGFBP5 identified a positive reaction in the undifferentiated dental papilla cells and differentiated odontoblasts, and the expression of Igfbp5 was reduced in the differentiated odontoblasts.ConclusionThe present study demonstrated the expression patterns of IGF-I, IGF-IR, IGFBP3, and IGFBP5 during odontoblast differentiation in mouse incisors. These results suggested that IGFBP3 regulates the transition from the proliferative to differentiation stage by inhibiting the action of IGF-I on the proliferation of dental papilla cells, and that IGFBP5 plays an important role in the maintenance of the differentiated odontoblasts during tooth development.     

Older adults’ social network and support and its association with physical activity

The purpose of this study was to describe older adults’ social network and support during a physical activity intervention and its association with physical activity. Mixed methods were used for this secondary analysis of existing data from a physical activity intervention. Seventy-three participants who completed a session by telephone on using support comprised the sample. Participants reported on average approximately eight individuals in their social network. Half reported support for physical activity from a spouse/partner, adult child, or friend. Those who perceived support for self-reported physical activity tended to have greater improvements on average from baseline for mean daily minutes of physical activity than those with no perceived support. Four-fifths developed a plan for a spouse/partner, friend, adult child, or sibling to provide physical activity support. Participants reported that the session was helpful and increased their confidence in using support; over one-quarter intended to use support after the intervention ended.     

Over-the-counter medications containing diphenhydramine and doxylamine used by older adults to improve sleep

International Journal of Clinical Pharmacy - Background The unintentional misuse of over-the-counter sleep aids among older adults is an important public health problem and a focus of Healthy...     

Multi-tissue DNA methylation age: Molecular relationships and perspectives for advancing biomarker utility

The multi-tissue DNA methylation estimator of chronological age (DNAm-age) has been associated with a wide range of exposures and health outcomes. Still, it is unclear how DNAm-age can have such broad relationships and how it can be best utilized as a biomarker. Understanding DNAm-age’s molecular relationships is a promising approach to address this critical knowledge gap. In this review, we discuss the existing literature regarding DNAm-age’s molecular relationships in six major categories: animal model systems, cancer processes, cellular aging processes, immune system processes, metabolic processes, and nucleic acid processes. We also present perspectives regarding the future of DNAm-age research, including the need to translate a greater number of ongoing research efforts to experimental and animal model systems.