Bone Ontogeny Research Articles

Bone Organoids: Recent Advances and Future Challenges.

Bone defects stemming from tumorous growths, traumatic events, and diverse conditions present a profound conundrum in clinical practice and research. While bone has the inherent ability to regenerate, substantial bone anomalies require bone regeneration techniques. Bone organoids represent a new concept in this field, involving the 3D self-assembly of bone-associated stem cells guided in vitro with or without extracellular matrix material, resulting in a tissue that mimics the structural, functional, and genetic properties of native bone tissue. Within the scientific panorama, bone organoids ascend to an esteemed status, securing significant experimental endorsement. Through a synthesis of current literature and pioneering studies, this review offers a comprehensive survey of the bone organoid paradigm, delves into the quintessential architecture and ontogeny of bone, and highlights the latest progress in bone organoid fabrication. Further, existing challenges and prospective directions for future research are identified, advocating for interdisciplinary collaboration to fully harness the potential of this burgeoning domain. Conclusively, as bone organoid technology continues to mature, its implications for both clinical and research landscapes are poised to be profound.

Skeletal-Vascular Interactions in Bone Development, Homeostasis, and Pathological Destruction.

Bone is a highly vascularized organ that not only plays multiple roles in supporting the body and organs but also endows the microstructure, enabling distinct cell lineages to reciprocally interact. Recent studies have uncovered relevant roles of the bone vasculature in bone patterning, morphogenesis, homeostasis, and pathological bone destruction, including osteoporosis and tumor metastasis. This review provides an overview of current topics in the interactive molecular events between endothelial cells and bone cells during bone ontogeny and discusses the future direction of this research area to find novel ways to treat bone diseases.

Trabecular bone ontogeny tracks neural development and life history among humans and non-human primates

Trabecular bone-the spongy bone inside marrow cavities-adapts to its mechanical environment during growth and development. Trabecular structure can therefore be interpreted as a functional record of locomotor behavior in extinct vertebrates. In this paper, we expand upon traditional links between form and function by situating ontogenetic trajectories of trabecular bone in four primate species into the broader developmental context of neural development, locomotor control, and ultimately life history. Our aim is to show that trabecular bone structure provides insights into ontogenetic variation in locomotor loading conditions as the product of interactions between increases in body mass and neuromuscular maturation.Our results demonstrate that age-related changes in trabecular bone volume fraction (BV/TV) are strongly and linearly associated with ontogenetic changes in locomotor kinetics. Age-related variation in locomotor kinetics and BV/TV is in turn strongly associated with brain and body size growth in all species. These results imply that age-related variation in BV/TV is a strong proxy for both locomotor kinetics and neuromuscular maturation. Finally, we show that distinct changes in the slope of age-related variation in bone volume fraction correspond to the age of the onset of locomotion and the age of locomotor maturity.Our findings compliment previous studies linking bone development to locomotor mechanics by providing a fundamental link to brain development and life history. This implies that trabecular structure of fossil subadults can be a proxy for the rate of neuromuscular maturation and major life history events like locomotor onset and the achievement of adult-like locomotor repertoires.

Endostructural and periosteal growth of the human humerus.

The growth and development of long bones are of considerable interests in the fields of comparative anatomy and palaeoanthropology, as evolutionary changes and adaptations to specific physical activity patterns are expected to be revealed during bone ontogeny. Traditionally, the cross-sectional geometry of long bones has been examined at discrete locations usually placed at set intervals or fixed percentage distances along the midline axis of the bone shaft. More recently, the technique of morphometric mapping has enabled the continuous analysis of shape variation along the shaft. Here we extend this technique to the full sequence of late fetal and postnatal development of the humeral shaft in a modern human population sample, with the aim of establishing the shape changes during growth and their relationship with the development of the arm musculature and activity patterns. A sample of modern human humeri from individuals of age ranging from 24 weeks in utero to 18 years was imaged using microtomography at multiple resolutions and custom Matlab scripts. Standard biomechanical properties, cortical thickness, surface curvature, and pseudo-landmarks were extracted along radial vectors spaced at intervals of 1° at each 0.5% longitudinal increment measured along the shaft axis. Heat maps were also generated for cortical thickness and surface curvature. The results demonstrate that a whole bone approach to analysis of cross-sectional geometry is more desirable where possible, as there is a continuous pattern of variation along the shaft. It is also possible to discriminate very young individuals and adolescents from other groups by relative cortical thickness, and also by periosteal surface curvature.

Growth and development of trabecular structure in the calcaneus of Japanese macaques (Macaca fuscata) reflects locomotor behavior, life history, and neuromuscular development.

Bone structure dynamically adapts to its mechanical environment throughout ontogeny by altering the structure of trabecular bone, the three‐dimensional mesh‐like structure found underneath joint surfaces. Trabecular structure, then, can provide a record of variation in loading directions and magnitude; and in ontogenetic samples, it can potentially be used to track developmental shifts in limb posture. We aim to broaden the analysis of trabecular bone ontogeny by incorporating interactions between ontogenetic variation in locomotor repertoire, neuromuscular maturation, and life history. We examine the associations between these variables and age‐related variation in trabecular structure in the calcaneus of Japanese macaques (Macaca fuscata). We used high‐resolution micro‐computed tomography scanning to image the calcaneus in a cross‐sectional sample of 34 juvenile M. fuscata aged between 0 and 7 years old at the Primate Research Institute, Japan. We calculated whole bone averages of standard trabecular properties and generated whole‐bone morphometric maps of bone volume fraction and Young’s modulus. Trabecular structure becomes increasingly heterogeneous in older individuals. Bone volume fraction (BV/total volume [TV]) decreases during the first month of life and increases afterward, coinciding with the onset of independent locomotion in M. fuscata. At birth, primary Young’s modulus is oriented orthogonal to the ossification center, but after locomotor onset bone structure becomes stiffest in the direction of joint surfaces and muscle attachments. Age‐related variation in bone volume fraction is best predicted by an interaction between the estimated percentage of adult brain size, body mass, and locomotor onset. To explain our findings, we propose a model where interactions between age‐related increases in body weight and maturation of the neuromuscular system alter the loading environment of the calcaneus, to which the internal trabecular structure dynamically adapts. This model cannot be directly tested based on our cross‐sectional data. However, confirmation of the model by longitudinal experiments and in multiple species would show that trabecular structure can be used both to infer behavior from fossil morphology and serve as a valuable proxy for neuromuscular maturation and life history events like locomotor onset and the achievement of an adult‐like gait. This approach could significantly expand our knowledge of the biology and behavior of fossil species.

Early ontogeny of humeral trabecular bone in Neandertals and recent modern humans

Trabecular bone ontogeny is well known in modern humans and unknown in Neandertals. Yet the bone developmental pattern is useful for interpreting fossils from evolutionary and functional perspectives. Interestingly, microstructure in early ontogeny is supposedly not influenced by high and specific mechanical loading related to the lifestyle of a human group and consequently does not directly depend on the activities of hunter-gatherers. Here, we specifically explored the early growth trajectories of the trabecular bone structure of the humerus and emphasized in particular how bone fraction (bone volume/total volume [BV/TV]) was built up in Neandertals, given the specific modern human bone loss after birth and the use of BV/TV in functional studies. Six Neandertals and 26 recent modern humans ranging from perinates to adolescents were included in this study. Six trabecular parameters were measured within a cubic region of interest extracted from the proximal metaphysis of the humerus. We found that the microstructural changes in Neandertals during early ontogeny (<1 year) fit with modern human growth trajectories for each parameter. The specific bone loss occurring immediately after birth in modern humans also occurred in Neandertals (but not in chimpanzees). However, the early childhood fossil Ferrassie 6 presented unexpectedly high BV/TV, whereas the high BV/TV in the Crouzade I adolescent was predictable. These results suggest that Neandertals and modern humans shared predetermined early growth trajectories and developmental mechanisms. We assume that the close relationship between skeletal characteristics in early ontogeny and adults in modern humans also existed in Neandertals. However, it was difficult to ensure that the high BV/TV in Neandertal early childhood, represented by only one individual, was at the origin of the high BV/TV observed in adults. Consequently, our study does not challenge the mechanical hypothesis that explains the trabecular gracilization of the humerus during the Holocene.

Molecular Cloning of Twist Gene and its Expression in Golden Pompano Trachinotus ovatus (Linnaeus 1758) Larvae at Different Water Temperatures

The twist gene in golden pompano Trachinotus ovatus larvae was cloned and analyzed in this study. in the first 18 days the expression of twist during larval fish ontogeny was explored, then on 18 day post hatch (DPH) the expression of twist in fish tissues was evaluated. Subsequently, the response of twist to water temperatures of 23, 26, and 29oC was compared on 12 DPH and 18 DPH. The cDNA sequence length of the twist gene in golden pompano is 880 bp with an open reading frame of 507 bp. The twist gene encodes 168 amino acids and has a calculated molecular weight of 18.93 kDa and a theoretical isoelectric point of 9.14. After hatching, the expression of twist increased with fish age, and peaked at 3 and 4 DPH. The highest expression of twist in fish tissue occurred in the spleen and stomach, followed by the brain and kidney on 18 DPH. On 12 DPH, the highest expression of twist was observed in fish reared at 26oC, and lowest expression was observed in fish reared at 29oC. On 18 DPH, the expression of twist was not significantly affected by the rearing temperatures. This study identified the gene expression of twist at the early developmental stage of golden pompano; the time dependent expression of twist in fish larvae may improve knowledge of bone ontogeny and formation in fish larvae.

Expression of Sox5, Sox8 and Sox9 Genes in Golden Pompano Trachinotus ovatus (Linnaeus 1758) Larvae During Ontogeny and in Response to Water Temperature

Sox5, Sox8, and Sox9 genes in golden pompano larvae were cloned and analyzed in this study. In the first trial, the expression of Sox genes during ontogeny of fish larvae in the first 18 days was examined, after which the expression of Sox genes in tissues was evaluated on 18 days post hatching (DPH). Subsequently, the response of Sox genes to water temperature (23, 26, and 29oC) on day 12 DPH and 18 DPH were compared. The expression levels of Sox8, Sox9a, and Sox9b peaked around 2 DPH before first feeding during fish ontogeny, and remained at low levels from 3-18 DPH. The expressions of Sox5 and Sox9a were affected by water temperature on 12 DPH and 18 DPH, while the expression of Sox8 was not affected by water temperature on 12 DPH and 18 DPH. The expression of Sox9b was affected by water temperature on 12 DPH. This study detected gene expression of Sox5, Sox8, and Sox9 at the early stage of development of golden pompano larvae. The time dependent expression of Sox genes in fish larvae is important for the understanding of bone ontogeny of fish larvae in early life.

Expression of Sox5, Sox8 and Sox9 Genes in Golden Pompano Trachinotus ovatus (Linnaeus 1758) Larvae During Ontogeny and in Response to Water Temperature

Sox5, Sox8, and Sox9 genes in golden pompano larvae were cloned and analyzed in this study. In the first trial, the expression of Sox genes during ontogeny of fish larvae in the first 18 days was examined, after which the expression of Sox genes in tissues was evaluated on 18 days post hatching (DPH). Subsequently, the response of Sox genes to water temperature (23, 26, and 29oC) on day 12 DPH and 18 DPH were compared. The expression levels of Sox8, Sox9a, and Sox9b peaked around 2 DPH before first feeding during fish ontogeny, and remained at low levels from 3-18 DPH. The expressions of Sox5 and Sox9a were affected by water temperature on 12 DPH and 18 DPH, while the expression of Sox8 was not affected by water temperature on 12 DPH and 18 DPH. The expression of Sox9b was affected by water temperature on 12 DPH. This study detected gene expression of Sox5, Sox8, and Sox9 at the early stage of development of golden pompano larvae. The time dependent expression of Sox genes in fish larvae is important for the understanding of bone ontogeny of fish larvae in early life.

Effects of the exposure to atrazine on bone development of Podocnemis expansa (Testudines, Podocnemididae).

The use of pesticides is a widely spread practice in Brazilian agriculture, and dispersion of these substances is an important factor for the fauna and flora. Atrazine is an endocrine disruptor in the xenoestrogen class that is used worldwide in agricultural practices. In Brazil, its use is permitted in several crops. Podocnemis expansa is a representative of the Testudines order that is the largest freshwater reptile of South America. Its distribution enables it to get in contact with molecules that are commonly used as pesticides, which may cause deleterious effects in target populations. In order to evaluate the possible effects of the exposure to atrazine on bone ontogeny of this species, eggs were artificially incubated in sand moistened with water contaminated with atrazine at concentrations equal to 0, 2, 20 or 200 μg/L. Embryos were collected throughout incubation and submitted to diaphanization of soft tissues with potassium hydroxide (KOH); bones were stained with Alizarin red S and cartilages by Alcian blue. Embryos were evaluated for the presence of abnormalities during the different stages of pre-natal development of skeletal elements. No effect of atrazine was observed on bone development during the embryonic phase in P. expansa individuals, in the conditions of this study.

Postnatal temporal bone ontogeny in Pan, Gorilla, and Homo, and the implications for temporal bone ontogeny in Australopithecus afarensis

Assessments of temporal bone morphology have played an important role in taxonomic and phylogenetic evaluations of fossil taxa, and recent three-dimensional analyses of this region have supported the utility of the temporal bone for testing taxonomic and phylogenetic hypotheses. But while clinical analyses have examined aspects of temporal bone ontogeny in humans, the ontogeny of the temporal bone in non-human taxa is less well documented. This study examines ontogenetic allometry of the temporal bone in order to address several research questions related to the pattern and trajectory of temporal bone shape change during ontogeny in the African apes and humans. We further apply these data to a preliminary analysis of temporal bone ontogeny in Australopithecus afarensis. Three-dimensional landmarks were digitized on an ontogenetic series of specimens of Homo sapiens, Pan troglodytes, Pan paniscus, and Gorilla gorilla. Data were analyzed using geometric morphometric methods, and shape changes throughout ontogeny in relation to size were compared. Results of these analyses indicate that, despite broadly similar patterns, African apes and humans show marked differences in development of the mandibular fossa and tympanic portions of the temporal bone. These findings indicate divergent, rather than parallel, postnatal ontogenetic allometric trajectories for temporal bone shape in these taxa. The pattern of temporal bone shape change with size exhibited by A. afarensis showed some affinities to that of humans, but was most similar to extant African apes, particularly Gorilla.

Solid Nomenclature: The Bedrock of Science. Similarities and Dissimilarities in Phenomena and Cells of Tooth and Bone Ontogeny

Solid Nomenclature: The Bedrock of Science. Similarities and Dissimilarities in Phenomena and Cells of Tooth and Bone Ontogeny

Cellular morphology and markers of cartilage and bone in the marine teleost Sparus auratus

Modifications have been characterised in terms of cellular organisation and the extracellular matrix (ECM) during bone ontogeny in the sea bream (Sparus auratus). During endochondral development, the agglomeration of matrix-secreting cells gives rise to chondrones; these chondrones frequently contain proliferating-cell-nuclear-antigen-positive cells, which subsequently become large collagen-II-positive cells with the characteristics of chondrocytes. Moreover, the matrix:cell ratio within the perichondrium increases, accompanied by a modification in ECM composition. Mineralisation of cartilage ECM is marked by a rapid fall in cell number, the switching off of collagen II transcription and the switching on of collagen X transcription, followed by collagen I transcription and bone mineralisation. The formation of dermal structures initiated upon the condensation of mesenchyme cells defines the future location of the dermal bone. Subsequent cellular differentiation gives rise to cells on the bone surface; these cells are positive for collagen I and osteonectin transcripts. The fish skeleton, with the exception of vertebrae, tends to comprise flattened bones that are covered by a monolayer of cells, the periosteum. A third type of tissue, present in gills, consists of chondrocyte-like cells embedded in a mineralised matrix resembling chondroid bone in mammals. The results suggest that the cellular organisation and ontogeny of endochondral and dermal bone in the sea bream are similar to those described in other vertebrates.

Cortical Bone Ontogeny: Activity, Nutritional Stress and Archaeology

AbstractThis poster introduces the idea that femoral compact bone growth and development demonstrates a very different pattern among infants and children in a contemporary sample of well-nourished active children versus archaeological samples of stressed, malnourished children.

Cortical Bone Ontogeny: Activity, Nutritional Stress and Archaeology

This poster introduces the idea that femoral compact bone growth and development demonstrates a very different pattern among infants and children in a contemporary sample of well-nourished active children versus archaeological samples of stressed, malnourished children.

Estimating body Mass and Nutritional Status from Subadult Hominin Skeletons

AbstractHominin body size and shape are key components to reconstructing phylogeny, life history, adaptation, and behavior in ancestral populations^1^. For adults, geometric properties of the femoral midshaft cross-section are used to infer locomotor behavior^2-5^, subsistence practices^6-7^, and functional adaptations^8-10^. Recently research has focused on patterns of compact bone ontogeny, particularly in regard to changes in bone strength with the acquisition of bipedal locomotion^11-13^ and examining population differences in ontogenetic trajectories for subadult humans^14-16^ and Neandertals^16^. Because femoral midshaft geometry is primarily shaped by biomechanical strains-weight bearing, locomotion, and muscle action-ontogenetic research requires estimates of body mass from the skeleton. Currently we use the width of the distal end of the femur to estimate subadult body mass but articular ends are constrained by pressures for joint congruence. Here I demonstrate the strong and consistent scaling relationship between body mass and femoral torsional strength (J) derived from measurement of midshaft cross-section geometry. Bone ends are most significantly affected by locomotor strain during the second year of life, during the initial acquisition of obligate bipedalism, after that time they are increasingly constrained by joint congruence. Results of a comparison of body mass for body size in prehistoric populations support the hypothesis that the midshaft is also a more sensitive indicator of population differences in body mass and activity levels during ontogeny. The femoral midshaft can be used to detect starvation and growth disruption in past populations because there is a mechano-biological interaction effect whereby disruptions in nutritional, metabolic and hormonal status lead to low body mass and activity levels^1, 11-13, 17-22^.

A theoretical model of endochondral ossification and bone architectural construction in long bone ontogeny

The role of mechanical stresses in the formation of endochondral ossification patterns and the construction of basic bone architecture in human long bones is investigated using a three-dimensional generalized model of long bone development. The distribution of mechanical stress which is created in developing bones as a result of intermittent mechanical loading is calculated using a computer model that mathematically represents the bone's geometry, material properties and loading conditions. The process of endochondral ossification is simulated by iteratively converting cartilaginous regions of the computer model to bone, based on the calculated intermittent hydrostatic and shear stress distributions. Once local regions of mineralized bone have formed, these regions are remodeled according to an algorithm which relates bone density to a mechanical stress stimulus. The results simulated the correct sequence of the appearance of morphological structures which are common to long bones in the human appendicular skeleton. These developmental structures include the site of the first endochondral bone and the secondary ossification center and the tubular nature of long bones. Our results suggest that mechanical loading histories may influence bone morphogenesis beginning from the early stages of endochondral ossification and continuing throughout life. The stress-based algorithms may be part of the 'rules of construction' or 'developmental constraints' which guide limb ontogeny.

Ontogeny of bone and the role of heterochrony in the myobatrachine genera Uperoleia, Crinia, and Pseudophryne (anura: Leptodactylidae: Myobatrachinae).

Descriptive data are provided for ontogeny of bone to metamorphosis in the myobatrachine species Uperoleia trachyderma; in pre- and postmetamorphic specimens of U. lithomoda, Crinia signifera, and Pseudophryne bibroni; and in postmetamorphic specimens of U. laevigata. Data derived from postmetamorphic U. laevigata indicate that dermal and endochondral elements ossify independently of each other in Uperoleia. Crinia signifera does not show the same degree of independence of ossification of dermal and endochondral elements as Uperoleia, whereas dermal and endochondral elements are not independent in P. bibroni. Ten (or possibly eleven) features are identified as being influenced by heterochrony within Uperoleia, confirming that the genus represents a highly pedomorphic lineage, four elements are influenced by heterochrony in Crinia, but only two in Pseudophryne.