Micro-anatomical record of cortical bone remodeling and high vascularity in a fossil giant rat midshaft femur

Rat cortical bone does not typically undergo secondary (Haversian) remodeling. Haversian organization of rat bone has been mainly observed in experimental settings following biomechanical or dietary manipulation. Here, we report an observation of cortical secondary osteons within a histological femur cross-section from an extinct (late Quaternary) form of Timorese giant rat (Murinae gen. et sp. indet). The medio-lateral midshaft diameter of its femur, used as a measure of bone size, is 6.15 mm and indicates a heavier than normal skeletal frame. We compare this sample to bone histology in a small rat's midshaft femur of 2.33 mm diameter. A complete lack of Haversian bone remodeling characteristics is noted for the smaller sample, which is dominated by radial vascular canals. The giant rat shows clear secondary osteons and diffuse vascularity mainly composed of tightly packed longitudinal canals across its cortex. It appears that rat cortical bone can undergo bone remodeling, and is organized in a highly vascularized manner, in insular giant cases. Our findings from Timor align with results reported in experimental rat model skeletal biology literature and other insular fossil rat material. Where macroanatomical examination is limited, histological observations on fossil rat limb bones have the potential to aid reconstructions of life history and skeletal growth aspects in these rodents. Anat Rec, 302:1934-1940, 2019.y. This research was possible thanks to OSP funds from the School of Archeology and Anthropology at the Australian National University (to Miszkiewicz), and the Australian Research Council (Future Fellowship Award FT160100450 to Louys; Laureate FL120100156 to O’Connor)

Ancient Human Bone Microstructure in Medieval England: Comparisons between Two Socio-Economic Groups

Understanding the links between bone microstructure and human lifestyle is critical for clinical and anthropological research into skeletal growth and adaptation. The present study is the first to report correspondence between socio-economic status and variation in bone microstructure in ancient humans. Products of femoral cortical remodeling were assessed using histological methods in a large human medieval sample (N:450) which represented two distinct socio-economic groups. Osteonal parameters were recorded in posterior midshaft femoral sections from adult males (N:233) and females (N:217). Using univariate and multivariate statistics, intact, fragmentary, and osteon population densities, Haversian canal area and diameter, and osteon area were compared between the two groups, accounting for sex, age, and estimated femoral robusticity. The size of osteons and their Haversian canals, as well as osteon density, varied significantly between the socio-economic groups, although minor inconsistencies were observed in females. Variation in microstructure was consistent with historical textual evidence that describes differences in mechanical loading and nutrition between the two groups. Results demonstrate that aspects of ancient human lifestyle can be inferred from bone microstructure

The importance of open access software in the analysis of bone histology in biological anthropology

Justyna J. Miszkiewicz receives funding from the Australian Research Council (ARC) under grant DE190100068

Deciduous enamel 3D microwear texture analysis as an indicator of childhood diet in medieval Canterbury, England

This study conducted the first three dimensional microwear texture analysis of human deciduous teeth to reconstruct the physical properties of medieval childhood diet (age 1-8yrs) at St Gregory's Priory and Cemetery (11th to 16th century AD) in Canterbury, England. Occlusal texture complexity surfaces of maxillary molars from juvenile skeletons (n=44) were examined to assess dietary hardness. Anisotropy values were calculated to reconstruct dietary toughness, as well as jaw movements during chewing. Evidence of weaning was sought, and variation in the physical properties of food was assessed against age and socio-economic status. Results indicate that weaning had already commenced in the youngest children. Diet became tougher from four years of age, and harder from age six. Variation in microwear texture surfaces was related to historical textual evidence that refers to lifestyle developments for these age groups. Diet did not vary with socio-economic status, which differs to previously reported patterns for adults. We conclude, microwear texture analyses can provide a non-destructive tool for revealing subtle aspects of childhood diet in the past

Linear Enamel Hypoplasia and Age-at- Death at Medieval (11

ABSTRACT Linear enamel hypoplasia (LEH) is a macroscopically detectable band-like dental defect, which represents localized decrease in enamel thickness caused by some form of disruption to a child's health. Such dental deformations are utilized in osteoarchaeological research as permanent markers of childhood physiological stress and have been extensively studied in numerous ancient human populations. However, currently there is no such data for medieval populations from Canterbury, UK. Here, LEH is examined in the context of age-at-death in human burials from the medieval St. Gregory's Priory and adjacent cemetery (11 th -16 th centuries), Canterbury, UK. The cemetery and Priory burials represented lower (n = 30) and higher status (n = 19) social groups, respectively. Linear enamel hypoplastic defects were counted on mandibular and maxillary anterior permanent teeth (n = 374). The age and sex of each skeleton were estimated using standard methods. Differences in LEH counts, age-at-death, and LEH formation ages were sought between the two social groups. Results indicate significantly greater frequencies of LEH in the Cemetery (mean = 17.6) compared to the Priory (mean = 7.9; t = À3.03, df = 46, p = 0.002). Adult age-at-death was also significantly lower in the Cemetery (mean = 39.8 years) compared to the Priory burials (mean = 44.1 years; t = 2.275, df = 47, p = 0.013). Hypoplasia formation ages differed significantly between the Priory (mean = 2.49 years) and Cemetery (mean = 3.22 years; t = 2.076; df = 47; p = 0.034) individuals. Results indicate that childhood stress may reflect adult mortality in this sample, and that the wellbeing of individuals from diverse social backgrounds can be successfully assessed using LEH analyses. Results are discussed in terms of the multifactorial etiology of LEH, as well as weaning-related LEH formation

Antibacterial Peptide Nucleic Acids—Facts and Perspectives

Antibiotic resistance is an escalating, worldwide problem. Due to excessive use of antibiotics, multidrug‐resistant bacteria have become a serious threat and a major global healthcare problem of the 21st century. This fact creates an urgent need for new and effective antimicrobials. The common strategies for antibiotic discovery are based on either modifying existing antibiotics or screening compound libraries, but these strategies have not been successful in recent decades. An alternative approach could be to use gene‐specific oligonucleotides, such as peptide nucleic acid (PNA) oligomers, that can specifically target any single pathogen. This approach broadens the range of potential targets to any gene with a known sequence in any bacterium, and could significantly reduce the time required to discover new antimicrobials or their redesign, if resistance arises. We review the potential of PNA as an antibacterial molecule. First, we describe the physicochemical properties of PNA and modifications of the PNA backbone and nucleobases. Second, we review the carriers used to transport PNA to bacterial cells. Furthermore, we discuss the PNA targets in antibacterial studies focusing on antisense PNA targeting bacterial mRNA and rRNA

Histomorphometry and cortical robusticity of the adult human femur

Recent quantitative analyses of human bone microanatomy, as well as theoretical models that propose bone micro- and gross anatomical associations, have started to reveal insights into biological links that may facilitate remodeling processes. However, relationships between bone size and the underlying cortical bone histology remain largely unexplored. The goal of this study is to determine the extent to which static indicators of bone remodeling and vascularity, measured using histomorphometric techniques, relate to femoral midshaft cortical width and robusticity. Using previously published and new quantitative data from 450 adult human male (n = 233) and female (n = 217) femora, we determine if these aspects of femoral size relate to bone microanatomy. Scaling relationships are explored and interpreted within a context of tissue form and function. Analyses revealed that the area and diameter of Haversian canals and secondary osteons, and densities of secondary osteons and osteocyte lacunae from the sub-periosteal region of the posterior midshaft femur cortex were significantly, but not consistently, associated with femoral size. Cortical width and bone robusticity were correlated with osteocyte lacunae density and scaled with positive allometry. Diameter and area of osteons and Haversian canals decreased as the width of cortex and bone robusticity increased, revealing a negative allometric relationship. These results indicate that measures of cortical bone remodeling and vascularity products link to femur size. Allometric relationships between more robust human femora with thicker cortical bone and histological products of bone remodeling correspond with principles of bone functional adaptation. Future studies may benefit from combining bone histomorphometric data with measurements of bone macrostructure

Socio-economic Determinants of Bone Health from Past to Present

Increasing epidemiology evidence amounts for social determinants of bone health underlying musculo-skeletal conditions such as osteoporosis. Amongst different facets influencing skeletal health, socio-economic status (SES) has been identified as a critical factor determining one’s access to resources, health care, education, nutrition, and physical activity. Recent conceptual and epigenetic studies assessing SES links with DNA methylation offer further support for the adverse effects of social disadvantage in early life on bone quantity and quality in adulthood. However, this evidence for socially patterned risks in bone fragility is not restricted to the contemporary society. Data exist for ancient human skeletal samples deriving from SES stratified cemeteries that also reflect bone changes consistent with lifestyles specific to social standing. Similarly to modern data, the conclusion drawn from the ancient times has been for a negative effect of low SES on bone growth and maintenance. Some contradictory results, mirroring previously reported inconsistencies in epidemiological studies, have also been reported showing that high SES can equally result in poor bone health. It becomes clear that ancient perspectives can offer a further line of support into these ongoing epidemiological and epigenetic research efforts. Taken together, a holistic approach to clinical understanding and practice of bone health is recommended, building upon ancient and modern findings to target living groups who are most at risk of developing low bone mass and compromised bone micro-architecture

Cartesian coordinates in two-dimensional bone histology images

Palaeohistologists who work with well-preserved hominin cortical bone can examine two-dimensional (2D) histology images for quantitative parameters of secondary osteons and Haversian canals to reconstruct past bone remodelling. Standard techniques in this space include area measurements and counts of histology components recorded from an image. The ‘point-count’ technique involves counting all the items (e.g., secondary osteons, osteocyte lacunae) of interest per image area. The open access image analysis software ImageJ/ FIJI facilitates this technique in a user-friendly way. Raw data points are captured and can be saved in a spreadsheet. Aside from the total number of counts, the software also issues Cartesian (XY) coordinates locating each counted point. These XY coordinates are typically neglected within palaeohistological approaches due their assumed irrelevance to research questions of bone remodelling significance. We provide a short evaluation of XY coordinates captured by ImageJ/FIJI from 2D bone histology images, and a protocol for a simple calculation of XY distances that follow the path of point counting. We focus on osteocyte lacunae which serve as a proxy for osteoblast-osteocyte conversion in live bone by replicating the protocol on a bone sample from a Medieval English individual. We discuss the potential of XY coordinates for reconstructing the proximity of osteocyte lacunae and related bone remodelling activity through exchange of nutrients by neighbouring cells. We recommend palaeohistologists report XY coordinate data in their results to ensure better hominin palaeobiology characterisation

Bone loss markers in the earliest Pacific Islanders

International audienceAbstract Kingdom of Tonga in Polynesia is one of the most obese nations where metabolic conditions, sedentary lifestyles, and poor quality diet are widespread. These factors can lead to poor musculoskeletal health. However, whether metabolic abnormalities such as osteoporosis occurred in archaeological populations of Tonga is unknown. We employed a microscopic investigation of femur samples to establish whether bone loss afflicted humans in this Pacific region approximately 3000 years ago. Histology, laser confocal microscopy, and synchrotron Fourier-transform infrared microspectroscopy were used to measure bone vascular canal densities, bone porosity, and carbonate and phosphate content of bone composition in eight samples extracted from adult Talasiu males and females dated to 2650 BP. Compared to males, samples from females had fewer vascular canals, lower carbonate and phosphate content, and higher bone porosity. Although both sexes showed evidence of trabecularised cortical bone, it was more widespread in females (35.5%) than males (15.8%). Our data suggest experiences of advanced bone resorption, possibly as a result of osteoporosis. This provides first evidence for microscopic bone loss in a sample of archaeological humans from a Pacific population widely afflicted by metabolic conditions today