Haruyoshi Yamaza

Individuals with disabilities who are unable to maintain oral intake are at high risk of inadequate oral hygiene because of reduced masticatory stimulation and impaired self‐cleansing, leading to excessive dental calculus accumulation. However, the effects of this on tooth eruption are poorly understood. Herein, we report the case of an 18‐year‐old boy with CHARGE syndrome managed with gastrostomy feeding since childhood. Following prolonged inadequate oral care, severe dental calculus accumulated throughout the dentition. Thick calculi encased the mandibular right first and second deciduous molars, physically obstructing eruption of the permanent premolars. Because safe delivery of care could not be ensured under local anesthesia, treatment was performed under general anesthesia. Full‐mouth scaling, mobile deciduous tooth extraction, and restorative procedures were performed. No periodontal pockets were observed, and radiographic assessment showed no alveolar bone resorption. After calculus removal, the impacted premolar erupted spontaneously within 2 months and had achieved complete eruption 8 months later. This case demonstrates that severe dental calculus accumulation can cause reversible eruption disturbances in children who do not receive oral intake. Early dental intervention, continuous oral hygiene management, and multidisciplinary care are essential for preventing oral and systemic complications in children with disabilities.

Pluripotent stem cell differentiation is commonly evaluated using in vivo assays; however, these approaches are time-consuming, technically demanding, and limited in experimental controllability. To address these limitations, we aimed to establish a controllable in vitro platform for studying the multi-lineage differentiation of human induced pluripotent stem cells (iPSCs) in a three-dimensional (3D) environment. We developed a Matrigel-based 3D culture system for the organoid-like differentiation of human iPSC-derived embryoid bodies (EBs), hereafter referred to as a Matrigel-based in vitro 3D differentiation platform (MIVDP). To generate EBs, naïve-like iPSCs carrying enhanced green fluorescent protein (EGFP), introduced via a piggyBac-based transposon system prior to naïve-like conversion, were used. These EBs were then embedded in Matrigel and cultured on membrane filters at the air-liquid interface in a standard medium, such as Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum, for up to three weeks. Under these conditions, EBs formed 3D multicellular structures containing various differentiated cell types derived from all three germ layers, as confirmed by histological and immunocytochemical analyses. Furthermore, when cultured in an osteogenic differentiation medium, EB-derived structures preferentially differentiated into osteoblast-like cells, as confirmed by Alizarin Red S staining and osteogenic marker gene expression. Because this system recapitulates certain aspects of multi-lineage differentiation and tissue organization, it can provide a controllable in vitro platform for studying the 3D differentiation and lineage specification of human iPSCs.

Hirschsprung disease (HSCR) and its associated disorders (AD-HSCR) often result in severe hypoperistalsis caused by enteric neuropathy, mesenchymopathy, and myopathy. Notably, HSCR involving the small intestine, isolated hypoganglionosis, chronic idiopathic intestinal pseudo-obstruction, and megacystis-microcolon-intestinal hypoperistalsis syndrome carry a poor prognosis. Ultimately, small-bowel transplantation (SBTx) is necessary for refractory cases, but it is highly invasive and outcomes are less than optimal, despite advances in surgical techniques and management. Thus, regenerative therapy has come to light as a potential form of treatment involving regeneration of the enteric nervous system, mesenchyme, and smooth muscle in affected areas. We review the cutting-edge regenerative therapeutic approaches for managing HSCR and AD-HSCR, including the use of enteric nervous system progenitor cells, embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells as cell sources, the recipient intestine's microenvironment, and transplantation methods. Perspectives on the future of these treatments are also discussed.

A subpopulation of mesenchymal stem cells, developmentally derived from multipotent neural crest cells that form multiple facial tissues, resides within the dental pulp of human teeth. These stem cells show high proliferative capacity in vitro and are multipotent, including adipogenic, myogenic, osteogenic, chondrogenic, and neurogenic potential. Teeth containing viable cells are harvested via minimally invasive procedures, based on various clinical diagnoses, but then usually discarded as medical waste, indicating the relatively low ethical considerations to reuse these cells for medical applications. Previous studies have demonstrated that stem cells derived from healthy subjects are an excellent source for cell-based medicine, tissue regeneration, and bioengineering. Furthermore, stem cells donated by patients affected by genetic disorders can serve as in vitro models of disease-specific genetic variants, indicating additional applications of these stem cells with high plasticity. This review discusses the benefits, limitations, and perspectives of patient-derived dental pulp stem cells as alternatives that may complement other excellent, yet incomplete stem cell models, such as induced pluripotent stem cells, together with our recent data.

Background: Human deciduous pulp stem cells (hDPSCs) have remarkable stem cell potency associated with cell proliferation, mesenchymal multipotency, and immunosuppressive function and have shown beneficial effects in a variety of animal disease models. Recent studies demonstrated that hDPSCs exhibited in vivo anti-fibrotic and anti-inflammatory action and in vivo hepatogenic-associated liver regeneration, suggesting that hDPSCs may offer a promising source with great clinical demand for treating liver diseases. However, how to manufacture ex vivo large-scale clinical-grade hDPSCs with the appropriate quality, safety, and preclinical efficacy assurances remains unclear. Methods: We isolated hDPSCs from human deciduous dental pulp tissues formed by the colony-forming unit-fibroblast (CFU-F) method and expanded them under a xenogeneic-free and serum-free (XF/SF) condition; hDPSC products were subsequently stored by two-step banking including a master cell bank (MCB) and a working cell bank (WCB). The final products were directly thawed hDPSCs from the WCB. We tested the safety and quality check, stem cell properties, and preclinical potentials of final hDPSC products and hDPSC products in the MCB and WCB. Results: We optimized manufacturing procedures to isolate and expand hDPSC products under a XF/SF culture condition and established the MCB and the WCB. The final hDPSC products and hDPSC products in the MCB and WCB were validated the safety and quality including population doubling ability, chromosome stability, microorganism safety, and stem cell properties including morphology, cell surface marker expression, and multipotency. We also evaluated the in vivo immunogenicity and tumorigenicity and validated in vivo therapeutic efficacy for liver regeneration in a CCl₄-induced chronic liver fibrosis mouse model in the final hDPSC products and hDPSC products in the WCB. Conclusion: The manufacture and quality control results indicated that the present procedure could produce sufficient numbers of clinical-grade hDPSC products from a tiny deciduous dental pulp tissue to enhance clinical application of hDPSC products in chronic liver fibrosis.

This review focuses on mechanisms of calorie restriction (CR), particularly the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis as an evolutionary conserved signal that regulates aging and lifespan, underlying the effects of CR in mammals. Topics include (1) the relation of the GH-IGF-1 signal with chronic low-level inflammation as one of the possible causative factors of aging, that is, inflammaging, (2) the isoform specificity of the forkhead box protein O (FoxO) transcription factors in CR-mediated regulation of cancer and lifespan, (3) the role for FoxO1 in the tumor-inhibiting effect of CR, (4) pleiotropic roles for FoxO1 in the regulation of disorders, and (5) sirtuin (Sirt) as a molecule upstream of FoxO. From the evolutionary view, the necessity of neuropeptide Y (Npy) for the effects of CR and the pleiotropic roles for Npy in life stages are also emphasized. Genes for mediating the effects of CR and regulating aging are context-dependent, particularly depending on nutritional states.