The Cellular Choreography of Osteoblast Angiotropism in Bone Development and Homeostasis.

Interaction between endothelial cells and osteoblasts is essential for bone development and homeostasis. This process is mediated in large part by osteoblast angiotropism, the migration of osteoblasts alongside blood vessels, which is crucial for the homing of osteoblasts to sites of bone formation during embryogenesis and in mature bones during remodeling and repair. Specialized bone endothelial cells that form "type H" capillaries have emerged as key interaction partners of osteoblasts, regulating osteoblast differentiation and maturation and ensuring their migration towards newly forming trabecular bone areas. Recent revolutions in high-resolution imaging methodologies for bone as well as single cell and RNA sequencing technologies have enabled the identification of some of the signaling pathways and molecular interactions that underpin this regulatory relationship. Similarly, the intercellular cross talk between endothelial cells and entombed osteocytes that is essential for bone formation, repair, and maintenance are beginning to be uncovered. This is a relatively new area of research that has, until recently, been hampered by a lack of appropriate analysis tools. Now that these tools are available, greater understanding of the molecular relationships between these key cell types is expected to facilitate identification of new drug targets for diseases of bone formation and remodeling.

Forever young: The end of history illusion in children.

The "end of history" illusion in adults (Quoidbach et al., 2013) is an asymmetrical pattern in which people accept that they've changed in the past but don't believe they will change in the future. We explore here whether the same psychological forces that cause the illusion in adults exist in the minds of children. Two studies with 4- to 11-year-olds (N = 256) suggest that they do, even in a within-subject design where the same child is asked questions about the past and the future. A third study (N = 83) finds that this illusion does not persist when children are asked about other people. These studies suggest that even young children believe that although they used to be different in the past, from this point on, they will remain forever young.

Learning to Trust Yourself: Decision-Making Skills Among Parents of Children With Medical Complexity.

CONTEXT: Children with medical complexity have substantial medical needs and their caregivers must make many challenging decisions about their care. Caregivers often become more involved in decisions over time, but it is unclear what skills they develop that facilitate this engagement. OBJECTIVES: To describe the skills that caregivers developed as they gained experience making medical decisions. METHODS: Eligible caregivers had a child who met referral criteria for their centre's Complex Care program for >1 year, were adults responsible for their child's medical decisions, and spoke English or a language with an available interpreter. We followed a semistructured interview guide to ask caregivers to describe and reflect on two challenging medical decisions that they made for their child-one early and one recent. Guided by interpretive description, we identified and refined themes in an iterative process. RESULTS: We conducted 15 interviews with 16 parents (14 [88%] women, two [13%] men) of a child with medical complexity (aged 1-17 years). Parents described 1) becoming more adept at managing decisional information, 2) recognizing the influence of the decision's context, 3) building stronger relationships with providers, and 4) becoming more effective at guiding their child's care as a decision-maker. As parents built these skills, they developed a greater sense of agency and confidence as decision-makers. CONCLUSION: Parents of children with medical complexity change how they approach decision making over time as they acquire relevant skills. These findings can inform the development of interventions to support skill-building among new caregivers.

Therapeutic avenues in bone repair: Harnessing an anabolic osteopeptide, PEPITEM, to boost bone growth and prevent bone loss.

The existing suite of therapies for bone diseases largely act to prevent further bone loss but fail to stimulate healthy bone formation and repair. We describe an endogenous osteopeptide (PEPITEM) with anabolic osteogenic activity, regulating bone remodeling in health and disease. PEPITEM acts directly on osteoblasts through NCAM-1 signaling to promote their maturation and formation of new bone, leading to enhanced trabecular bone growth and strength. Simultaneously, PEPITEM stimulates an inhibitory paracrine loop: promoting osteoblast release of the decoy receptor osteoprotegerin, which sequesters RANKL, thereby limiting osteoclast activity and bone resorption. In disease models, PEPITEM therapy halts osteoporosis-induced bone loss and arthritis-induced bone damage in mice and stimulates new bone formation in osteoblasts derived from patient samples. Thus, PEPITEM offers an alternative therapeutic option in the management of diseases with excessive bone loss, promoting an endogenous anabolic pathway to induce bone remodeling and redress the imbalance in bone turnover.

Clinical characteristics of children with severe neurologic impairment: A scoping review.

OBJECTIVE: The aim of this study is to extrapolate the clinical features of children with severe neurologic impairment (SNI) based on the functional characteristics and comorbidities described in published studies. METHODS: Four databases were searched. We included studies that describe clinical features of a group of children with SNI (≥20 subjects <19 years of age with >1 neurologic diagnosis and severe functional limitation) using data from caregivers, medical charts, or prospective collection. Studies that were not written in English were excluded. We extracted data about functional characteristics, comorbidities, and study topics. RESULTS: We included 102 studies, spanning 5 continents over 43 years, using 41 distinct terms for SNI. The terms SNI and neurologic impairment (NI) were used in 59 studies (58%). Most studies (n = 81, 79%) described ≥3 types of functional characteristics, such as technology assistance and motor impairment. Studies noted 59 comorbidities and surgeries across 10 categories. The most common comorbidities were related to feeding, nutrition, and the gastrointestinal system, which were described in 79 studies (77%). Most comorbidities (76%) were noted in <10 studies. Studies investigated seven clinical topics, with "Gastrointestinal reflux and feeding tubes" as the most common research focus (n = 57, 56%). The next most common topic, "Aspiration and respiratory issues," included 13 studies (13%). Most studies (n = 54, 53%) were retrospective cohorts or case series; there were no clinical trials. CONCLUSIONS: Despite the breadth of described comorbidities, studies focused on a narrow set of clinical topics. Further research is required to understand the prevalence, clinical impact, and interaction of the multiple comorbidities that are common in children with SNI.

A detailed methodology for a three-dimensional, self-structuring bone model that supports the differentiation of osteoblasts towards osteocytes and the production of a complex collagen-rich mineralised matrix.

Background: There are insufficient in vitro bone models that accommodate long-term culture of osteoblasts and support their differentiation to osteocytes. The increased demand for effective therapies for bone diseases, and the ethical requirement to replace animals in research, warrants the development of such models.Here we present an in-depth protocol to prepare, create and maintain three-dimensional, in vitro, self-structuring bone models that support osteocytogenesis and long-term osteoblast survival (>1 year). Methods: Osteoblastic cells are seeded on a fibrin hydrogel, cast between two beta-tricalcium phosphate anchors. Analytical methods optimised for these self-structuring bone model (SSBM) constructs, including RT-qPCR, immunofluorescence staining and XRF, are described in detail. Results: Over time, the cells restructure and replace the initial matrix with a collagen-rich, mineralising one; and demonstrate differentiation towards osteocytes within 12 weeks of culture. Conclusions: Whilst optimised using a secondary human cell line (hFOB 1.19), this protocol readily accommodates osteoblasts from other species (rat and mouse) and origins (primary and secondary). This simple, straightforward method creates reproducible in vitro bone models that are responsive to exogenous stimuli, offering a versatile platform for conducting preclinical translatable research studies.

Not the same same: Distinguishing between similarity and identity in judgments of change.

What makes someone the same person over time? There are (at least) two ways of understanding this question: A person can be the same in the sense of being very similar to how they used to be (similarity), or they can be the same in the sense of being the same individual (numerical identity). In recent years, several papers have claimed to explore the commonsense notion of numerical identity. However, we suggest here that these researchers have instead been studying similarity. We develop a novel method that uses simple intuitions about objects to illustrate these two notions of "same person", and then asks which concept applies to instances of personal change. Across 4 studies (N = 2446), we find that these previously documented intuitions are best understood as reflecting judgments about similarity, not identity (Experiments 1 and 2). We then use this method to explore the situations in which participants do perceive a change in numerical identity. We find that when a person's entire brain (Experiments 3 and 4) or soul (Experiment 4) has been replaced with that of another person, the majority of participants judge that numerical identity has changed. However, we also note that a substantial minority of participants denied that identity had changed, opening new questions about the role of the body in intuitive judgments of personal identity.