A policy overview of Japan's progress on dementia care in a super-aged society and future challenges.

Dementia is highly prevalent in Japan, a super-aged society where almost a third of the population is above 65 years old. Japan has been implementing ageing and dementia policies since 2000 and now has a wealth of experience to share with other nations who are anticipating a similar future regarding dementia. This article focuses on the 2019 National Framework for Promotion of Dementia Policies that, based on its philosophy of Inclusion and Risk Reduction, lays out five complementary strategies. Together, these five strategies encourage a whole of society approach in dementia care. We first elaborate on the activities being undertaken under each of these strategies and then discuss the future challenges that Japan needs to address. These policy and social innovations spearheaded by Japan can be useful information for other countries that are anticipating similar future as Japan.

Validity and reliability of the Oura Ring Generation 3 (Gen3) with Oura sleep staging algorithm 2.0 (OSSA 2.0) when compared to multi-night ambulatory polysomnography: A validation study of 96 participants and 421,045 epochs.

PURPOSE: To evaluate the validity and the reliability of the Oura Ring Generation 3 (Gen3) with Oura Sleep Staging Algorithm 2.0 (OSSA 2.0) through multi-night polysomnography (PSG). PARTICIPANTS AND METHODS: Participants were 96 generally healthy Japanese men and women aged between 20 and 70 years contributing with 421,045 30-s epochs. Sleep scoring was performed according to American Academy of Sleep Medicine criteria. Each participant could contribute with a maximum of three polysomnography (PSG) nights. Within-participant means were created for each sleep measure and paired t-tests were used to compare equivalent measures obtained from the PSG and Oura Rings (non-dominant and dominant hand). Agreement between sleep measures were assessed using Bland-Altman plots. Interrater reliability for epoch accuracy was determined by prevalence-adjusted and bias-adjusted kappa (PABAK). RESULTS: The Oura Ring did not significantly differ from PSG for the measures time in bed, total sleep time, sleep onset latency, sleep period time, wake after sleep onset, time spent in light sleep, and time spent in deep sleep. Oura Rings worn on the non-dominant- and dominant-hand underestimated sleep efficiency by 1.1 %-1.5 % and time spent in REM sleep by 4.1-5.6 min. The Oura Ring had a sensitivity of 94.4 %-94.5 %, specificity of 73.0 %-74.6 %, a predictive value for sleep of 95.9 %-96.1 %, a predictive value for wake of 66.6 %-67.0 %, and accuracy of 91.7 %-91.8 %. PABAK was 0.83-0.84 and reliability was 94.8 %. Sleep staging accuracy ranged between 75.5 % (light sleep) and 90.6 % (REM sleep). CONCLUSIONS: The Oura Ring Gen3 with OSSA 2.0 shows good agreement with PSG for global sleep measures and time spent in light and deep sleep.

Injectable phase-separated tetra-armed poly(ethylene glycol) hydrogel scaffold allows sustained release of growth factors to enhance the repair of critical bone defects.

With the rising prevalence of bone-related injuries, it is crucial to improve treatments for fractures and defects. Tissue engineering offers a promising solution in the form of injectable hydrogel scaffolds that can sustain the release of growth factors like bone morphogenetic protein-2 (BMP-2) for bone repair. Recently, we discovered that tetra-PEG hydrogels (Tetra gels) undergo gel-gel phase separation (GGPS) at low polymer content, resulting in hydrophobicity and tissue affinity. In this work, we examined the potential of a newer class of gel, the oligo-tetra-PEG gel (Oligo gel), as a growth factor-releasing scaffold. We investigated the extent of GGPS occurring in the two gels and assessed their ability to sustain BMP-2 release and osteogenic potential in a mouse calvarial defect model. The Oligo gel underwent a greater degree of GGPS than the Tetra gel, exhibiting higher turbidity, hydrophobicity, and pore formation. The Oligo gel demonstrated sustained protein or growth factor release over a 21-day period from protein release kinetics and osteogenic cell differentiation studies. Finally, BMP-2-loaded Oligo gels achieved complete regeneration of critical-sized calvarial defects within 28 days, significantly outperforming Tetra gels. The easy formulation, injectability, and capacity for sustained release makes the Oligo gel a promising candidate therapeutic biomaterial.

Probing the Molecular Mechanism of Viscoelastic Relaxation in Transient Networks.

Hydrogels, which have polymer networks through supramolecular and reversible interactions, exhibit various mechanical responsibilities to its surroundings. The influence of the reversible bonds on a hydrogel's macroscopic properties, such as viscoelasticity and dynamics, is not fully understood, preventing further innovative material development. To understand the relationships between the mechanical properties and molecular structures, it is required to clarify the molecular understanding of the networks solely crosslinked by reversible interactions, termed "transient networks". This review introduces our recent progress on the studies on the molecular mechanism of viscoelasticity in transient networks using multiple methods and model materials. Based on the combination of the viscoelasticity and diffusion measurements, the viscoelastic relaxation of transient networks does not undergo the diffusion of polymers, which is not explained by the framework of conventional molecular models for the viscoelasticity of polymers. Then, we show the results of the comparison between the viscoelastic relaxation and binding dynamics of reversible bonds. Viscoelastic relaxation is primarily affected by "dissociation dynamics of the bonds" and "network structures". These results are explained in the framework that the backbone, which is composed of essential chains supporting the stress, is broken by multiple dissociation events. This understanding of molecular dynamics in viscoelasticity will provide the foundation for designing transient networks.

Practical Compass of Single-Cell RNA-Seq Analysis.

PURPOSE OF REVIEW: This review paper provides step-by-step instructions on the fundamental process, from handling fastq datasets to illustrating plots and drawing trajectories. RECENT FINDINGS: The number of studies using single-cell RNA-seq (scRNA-seq) is increasing. scRNA-seq revealed the heterogeneity or diversity of the cellular populations. scRNA-seq also provides insight into the interactions between different cell types. User-friendly scRNA-seq packages for ligand-receptor interactions and trajectory analyses are available. In skeletal biology, osteoclast differentiation, fracture healing, ectopic ossification, human bone development, and the bone marrow niche have been examined using scRNA-seq. scRNA-seq data analysis tools are still being developed, even at the fundamental step of dataset integration. However, updating the latest information is difficult for many researchers. Investigators and reviewers must share their knowledge of in silico scRNA-seq for better biological interpretation. This review article aims to provide a useful guide for complex analytical processes in single-cell RNA-seq data analysis.

Percolation-induced gel-gel phase separation in a dilute polymer network.

Cosmic large-scale structures, animal flocks and living tissues can be considered non-equilibrium organized systems created by dissipative processes. Replicating such properties in artificial systems is still difficult. Herein we report a dissipative network formation process in a dilute polymer-water mixture that leads to percolation-induced gel-gel phase separation. The dilute system, which forms a monophase structure at the percolation threshold, spontaneously separates into two co-continuous gel phases with a submillimetre scale (a dilute-percolated gel) during the deswelling process after the completion of the gelation reaction. The dilute-percolated gel, which contains 99% water, exhibits unexpected hydrophobicity and induces the development of adipose-like tissues in subcutaneous tissues. These findings support the development of dissipative structures with advanced functionalities for distinct applications, ranging from physical chemistry to tissue engineering.

Modeling of intramembranous ossification using human pluripotent stem cell-derived paraxial mesoderm derivatives.

Vertebrates form their skeletal tissues from three distinct origins (the neural crest, paraxial mesoderm, and lateral plate mesoderm) through two distinct modes of ossification (intramembranous and endochondral ossification). Since the paraxial mesoderm generates both intramembranous and endochondral bones, it is thought to give rise to both osteoprogenitors and osteo-chondroprogenitors. However, it remains unclear what directs the paraxial mesoderm-derived cells toward these different fates in distinct skeletal elements during human skeletal development. To answer this question, we need experimental systems that recapitulate paraxial mesoderm-mediated intramembranous and endochondral ossification processes. In this study, we aimed to develop a human pluripotent stem cell (hPSC)-based system that models the human intramembranous ossification process. We found that spheroid culture of the hPSC-derived paraxial mesoderm derivatives generates osteoprogenitors or osteo-chondroprogenitors depending on stimuli. The former induced intramembranous ossification, and the latter endochondral ossification, in mouse renal capsules. Transcriptional profiling supported the notion that bone signatures were enriched in the intramembranous bone-like tissues. Thus, we developed a system that recapitulates intramembranous ossification, and that enables the induction of two distinct modes of ossification by controlling the cell fate of the hPSC-derived paraxial mesoderm derivatives.

Tissue-Adhesive Hydrogel Spray System for Live Cell Immobilization on Biological Surfaces.

Gelatin hydrogels are used as three-dimensional cell scaffolds and can be prepared using various methods. One widely accepted approach involves crosslinking gelatin amino groups with poly(ethylene glycol) (PEG) modified with N-hydroxysuccinimide ester (PEG-NHS). This method enables the encapsulation of live cells within the hydrogels and also facilitates the adhesion of the hydrogel to biological tissues by crosslinking their surface amino groups. Consequently, these hydrogels are valuable tools for immobilizing cells that secrete beneficial substances in vivo. However, the application of gelatin hydrogels is limited due to the requirement for several minutes to solidify under conditions of neutral pH and polymer concentrations suitable for live cells. This limitation makes it impractical for use with biological tissues, which have complex shapes or inclined surfaces, restricting its application to semi-closed spaces. In this study, we propose a tissue-adhesive hydrogel that can be sprayed and immobilized with live cells on biological tissue surfaces. This hydrogel system combines two components: (1) gelatin/PEG-NHS hydrogels and (2) instantaneously solidifying PEG hydrogels. The sprayed hydrogel solidified within 5 s after dispensing while maintaining the adhesive properties of the PEG-NHS component. The resulting hydrogels exhibited protein permeability, and the viability of encapsulated human mesenchymal stem/stromal cells (hMSCs) remained above 90% for at least 7 days. This developed hydrogel system represents a promising approach for immobilizing live cells on tissue surfaces with complex shapes.

A Disentangled VAE-BiLSTM Model for Heart Rate Anomaly Detection.

Cardiovascular diseases (CVDs) remain a leading cause of death globally. According to the American Heart Association, approximately 19.1 million deaths were attributed to CVDs in 2020, in particular, ischemic heart disease and stroke. Several known risk factors for CVDs include smoking, alcohol consumption, lack of regular physical activity, and diabetes. The last decade has been characterized by widespread diffusion in the use of wristband-style wearable devices which can monitor and collect heart rate data, among other information. Wearable devices allow the analysis and interpretation of physiological and activity data obtained from the wearer and can therefore be used to monitor and prevent potential CVDs. However, these data are often provided in a manner that does not allow the general user to immediately comprehend possible health risks, and often require further analytics to draw meaningful conclusions. In this paper, we propose a disentangled variational autoencoder (ß-VAE) with a bidirectional long short-term memory network (BiLSTM) backend to detect in an unsupervised manner anomalies in heart rate data collected during sleep time with a wearable device from eight heterogeneous participants. Testing was performed on the mean heart rate sampled both at 30 s and 1 min intervals. We compared the performance of our model with other well-known anomaly detection algorithms, and we found that our model outperformed them in almost all considered scenarios and for all considered participants. We also suggest that wearable devices may benefit from the integration of anomaly detection algorithms, in an effort to provide users more processed and straightforward information.

Miscibility and ternary diagram of aqueous polyvinyl alcohols with different degrees of saponification.

Liquid-liquid phase separation (LLPS), an important phenomenon in the field of polymer science and material design, plays an essential role in cells and living bodies. Poly(vinyl alcohol) (PVA) is a popular semicrystalline polymer utilized in the synthesis of artificial biomaterials. The aqueous solutions of its derivatives with tuned degrees of saponification (DS) exhibit LLPS. However, the miscibility and LLPS behavior of PVA aqueous solution are still unclear. This study describes the miscibility diagram of the ternary mixture, where water and two types of poly(vinyl alcohol) (PVA) with different DSs [98 (PVA98), 88 (PVA88), 82 (PVA82), and 74 mol% (PVA74)] were blended. UV-Vis measurement was conducted to evaluate the miscibility. Immiscibility was more pronounced at elevated temperatures, exhibiting LLPS. The ternary immiscibility diagram, displaying miscible-immiscible behaviors in the aqueous mixtures of PVA74:PVA98, PVA82:PVA98, and PVA88:PVA98 (blended at a constant volume ratio), indicated that increasing the concentration, temperature, and blend ratio of PVAs at a lower DS increased immiscibility, suggesting that the free energy of mixing increases with increasing these parameters. The miscible-immiscible behaviors of PVAs/water systems provide fundamental knowledge about LLPS and the design of PVA-based materials.

Need for Improvements in Medical Device Management in Low- and Middle-Income Countries: Applying Learnings from Japan's Experience.

Medical devices provide important infrastructural support in modern healthcare systems. However, in low- and middle-income countries (LMICs), inadequate maintenance and management of devices due to a shortage of healthcare personnel (not only doctors and nurses but also other professionals including biomedical engineers [BMEs]) has resulted in inefficient and weak healthcare systems. High-income countries, including Japan, have resolved these problems by developing human resources and technologies to maintain and manage these systems. In this paper, we discuss the possibility of mitigating these problems in LMICs through human resource development and technology, based on lessons from Japan's experience. The problem of medical device management in LMICs stems from the fact that there are few professionals, such as BMEs, in charge of the management of medical devices and that clinical engineering departments in charge of device management have not been established. Since the 1980s, Japan has introduced a licensing system for BMEs, establishing operational guidelines to clarify their responsibilities within hospitals and using technology to utilize data and reduce workloads. Nevertheless, workload problems and high costs required to introduce computerized management systems persist. Moreover, it would be difficult to implement the same measures as those adopted in Japan in LMICs where there is an overwhelming shortage of medical personnel. It may be necessary to further reduce workloads for data entry and device management; use up-to-date, inexpensive, and user-friendly technology; and train non-BME personnel to operate and maintain equipment.

The ME-BYO index: A development and validation project of a novel comprehensive health index.

Quantifying health status and identifying modifiable factors are essential for effective and individualized prevention of age-related conditions and for promoting health during aging. The ME-BYO concept from Kanagawa Prefecture, one of Japan's largest prefectures, can be used to establish a healthy aging society. In disease etiology, ME-BYO considers the status of an individual's body and mind as changing continuously from healthy to sick instead of being a dichotomy between the two. ME-BYO conceptualizes the entire process of this change. The ME-BYO index was developed in 2019 to comprehensively and numerically measure and visualize an individual's current health status and future disease risk by quantifying data on the four domains of metabolic function, locomotor function, cognitive function, and mental resilience. The ME-BYO index has been implemented in the personal health management application "My ME-BYO." However, scientific validation of this index and the development of a practical application using healthcare data remain to be completed. In 2020, our research team started a project to refine the ME-BYO index using data from the Kanagawa ME-BYO prospective cohort study, which is a large population-based genomic cohort study. This project will scientifically evaluate the ME-BYO index and develop a practical application for promoting healthy aging.

Stem cell-based modeling and single-cell multiomics reveal gene-regulatory mechanisms underlying human skeletal development.

Although the skeleton is essential for locomotion, endocrine functions, and hematopoiesis, the molecular mechanisms of human skeletal development remain to be elucidated. Here, we introduce an integrative method to model human skeletal development by combining in vitro sclerotome induction from human pluripotent stem cells and in vivo endochondral bone formation by implanting the sclerotome beneath the renal capsules of immunodeficient mice. Histological and scRNA-seq analyses reveal that the induced bones recapitulate endochondral ossification and are composed of human skeletal cells and mouse circulatory cells. The skeletal cell types and their trajectories are similar to those of human embryos. Single-cell multiome analysis reveals dynamic changes in chromatin accessibility associated with multiple transcription factors constituting cell-type-specific gene-regulatory networks (GRNs). We further identify ZEB2, which may regulate the GRNs in human osteogenesis. Collectively, these results identify components of GRNs in human skeletal development and provide a valuable model for its investigation.

Association between Metabolic Syndrome Status and Daily Physical Activity Measured by a Wearable Device in Japanese Office Workers.

(1) Background: This study examined the cross-sectional association between metabolic syndrome (MetS) status classified into three groups and daily physical activity (PA; step count and active minutes) using a wearable device in Japanese office workers. (2) Methods: This secondary analysis used data from 179 participants in the intervention group of a randomized controlled trial for 3 months. Individuals who had received an annual health check-up and had MetS or were at a high risk of MetS based on Japanese guidelines were asked to use a wearable device and answer questionnaires regarding their daily life for the entire study period. Multilevel mixed-effects logistic regression models adjusted for covariates associated with MetS and PA were used to estimate associations. A sensitivity analysis investigated the associations between MetS status and PA level according to the day of the week. (3) Results: Compared to those with no MetS, those with MetS were not significantly associated with PA, while those with pre-MetS were inversely associated with PA [step count Model 3: OR = 0.60; 95% CI: 0.36, 0.99; active minutes Model 3: OR = 0.62; 95% CI: 0.40, 0.96]. In the sensitivity analysis, day of the week was an effect modifier for both PA (p < 0.001). (4) Conclusions: Compared to those with no MetS, those with pre-MetS, but not MetS, showed significantly lower odds of reaching their daily recommended PA level. Our findings suggest that the day of the week could be a modifier for the association between MetS and PA. Further research with longer study periods and larger sample sizes are needed to confirm our results.

Surface modulation of extracellular vesicles with cell-penetrating peptide-conjugated lipids for improvement of intracellular delivery to endothelial cells.

Exosomes (diameter 30-200 nm) are a subtype of extracellular vesicles secreted by cells containing DNA, microRNA (miRNA), and proteins. Exosomes are expected to be valuable as a means of delivering drugs or functional miRNAs in treatment of diseases. However, the delivery of exosomes is not sufficiently effective, even though exosomes have intrinsic delivery functions. Cell-penetrating peptides (CPPs) are short peptide families that facilitate cellular intake of molecules and vesicles. We previously reported that the modification of cells, and liposomes with CPP-conjugated-lipids, CPPs conjugated with poly (ethylene glycol)-conjugated phospholipids (PEG-lipid), that induce adhesion by CPPs, can be useful for cell-based assays and harvesting liposomes. In this study, we aimed to modulate the exosome surface using Tat peptide (YGRKKRRQRRR)-PEG-lipids to improve intracellular delivery to endothelial cells. We isolated and characterized exosomes from the medium of HEK 293 T cell cultures. Tat conjugated PEG-lipids with different spacer molecular weights and lipid types were incorporated into exosomes using fluorescein isothiocyanate labeling to optimize the number of Tat-PEG-lipids immobilized on the exosome surface. The exosomes modified with Tat-PEG-lipids were incubated with human umbilical vein endothelial cells (HUVECs) to study the interaction. Tat conjugated with 5 kDa PEG and C16 lipids incorporated on the exosome surface were highly detected inside HUVECs by flow cytometry. Fluorescence was negligible in HUVECs for control groups. Thus, Tat-PEG-lipids can be modified on the exosome surface, improving the intracellular delivery of exosomes.

Orally administrable peptides derived from egg yolk promote skeletal repair and ameliorate degenerative skeletal disorders in mouse models.

Introduction: Aging, genetic mutations, and other pathological conditions cause impairment of skeletal growth and bone metabolism, which affect activities of daily living and quality of life in all life stages. Although several drugs have been used in clinical settings and new drugs have been developed for the treatment of skeletal degenerative disorders such as osteoporosis and genetic disorders such as osteogenesis imperfecta (OI), there is clear demand for development of new drugs, especially orally available anabolic drugs that are applicable for a wide range of skeletal disorders. Methods: To identify therapeutic candidates for skeletal disorders, peptide screening was performed. To validate the identified peptides, we performed a bone histomorphometric analysis with rat bone tissues and in vitro cell proliferation assays of skeletal cells. To understand the metabolism of the peptides, we performed a biochemical analysis, followed by in vitro assays for proliferation and differentiation of skeletal cells. We examined the therapeutic efficacy of the identified peptides with several mouse models representing skeletal disorders including bone fracture, osteoporosis, and osteogenesis imperfecta. In vivo therapeutic effects of the candidate were assessed with radiological analysis and mechanical property tests. Results: We identified the egg yolk-derived functional peptide PF201. PF201 promoted in vivo bone formation in rodents and enhanced proliferation of osteoblasts and chondrocytes in vitro. D2, a metabolite of PF201, was present and circulated after digestion and absorption in the digestive tract. D2 had positive impacts on the proliferation and differentiation of mesenchymal stem cells and preosteoblasts. Oral administration of D2 accelerated bone healing in a mouse fracture model. D2 also improved bone strength and fracture healing under ovariectomy-induced osteoporotic conditions in mice, and D2 showed a therapeutic effect in a mouse OI model. Conclusion: D2 is likely to be a candidate for an orally available therapeutic for a range of skeletal disorders.

Decoupling between Translational Diffusion and Viscoelasticity in Transient Networks with Controlled Network Connectivity.

The mobility of sustained molecules is influenced by viscoelasticity, which is strongly correlated with the diffusional property in polymeric liquid. However, the study of transient networks formed by a reversible crosslink, which is the viscoelastic liquid, was insufficient due to the absence of a model system. We compare the viscoelastic and diffusional properties of the transient networks, using the model system with controlled network connectivity (Tetra-PEG slime). According to independent measurements of viscoelasticity and diffusion, the root-mean-square distance the polymer diffuses during the viscoelastic relaxation time shows a large deviation from the self-size of the polymer, which is contrary to the conventional understanding. This decoupling between viscoelasticity and diffusion is unique for transient networks, suggesting that the viscoelastic relaxation is not induced by the diffusion of one prepolymer, particularly in the network with low connectivity. These findings will provide a definite basis for discussion to understand the viscoelasticity in transient networks.