Effects of upadacitinib on enthesitis in patients with psoriatic arthritis: a post hoc analysis of SELECT-PsA 1 and 2.

OBJECTIVES: To characterize the effect of upadacitinib 15 mg once daily (UPA15) on enthesitis in patients with psoriatic arthritis from the SELECT-PsA Phase 3 trials. METHODS: Patients with an inadequate response/intolerance to ≥ 1 non-biologic DMARD (SELECT-PsA 1) or ≥ 1 biologic DMARD (SELECT-PsA 2) received UPA15, adalimumab 40 mg every other week or placebo (weeks 0-24) switched to UPA15 (week 24 onward). The Leeds Enthesitis Index (LEI) and Spondyloarthritis Research Consortium of Canada (SPARCC) index were used to assess improvement in enthesitis, enthesitis resolution, maintenance of enthesitis resolution, and protection from enthesitis development through week 56. RESULTS: Data from 639 patients receiving UPA15 and 635 patients receiving placebo (including 317 patients who switched from placebo to UPA15) were analysed. UPA15 led to higher rates of enthesitis resolution vs placebo at week 24 (LEI: 59.8% vs 38.0%; SPARCC index: 50.6% vs 31.5%, respectively) and greater improvements in the LEI (-1.7 vs -1.0) and SPARCC index (-3.4 vs -1.9); improvements were maintained through week 56. Improvements were observed after 12 weeks of UPA15 treatment. Over 90% of patients without enthesitis (LEI = 0) at baseline receiving UPA15 were enthesitis-free at week 56, and UPA15 prevented recurrence of enthesitis at week 56 in > 80% of patients with enthesitis at baseline who achieved resolution (LEI = 0) at week 24. CONCLUSIONS: UPA15 is associated with a comprehensive improvement in enthesitis, with improvements observed after 12 weeks of treatment. Additionally, treatment with UPA15 was associated with maintaining an enthesitis-free state after resolution and protection against new-onset enthesitis. CLINICALTRIALS.GOV IDENTIFIERS: NCT03104400 (SELECT-PsA 1) and NCT03104374 (SELECT-PsA 2).

Humanlike manual activities in Australopithecus.

The evolution of the human hand is a topic of great interest in paleoanthropology. As the hand can be involved in a vast array of activities, knowledge regarding how it was used by early hominins can yield crucial information on the factors driving biocultural evolution. Previous research on early hominin hands focused on the overall bone shape. However, while such approaches can inform on mechanical abilities and the evolved efficiency of manipulation, they cannot be used as a definite proxy for individual habitual activity. Accordingly, it is crucial to examine bone structures more responsive to lifetime biomechanical loading, such as muscle attachment sites or internal bone architecture. In this study, we investigate the manual entheseal patterns of Australopithecus afarensis, Australopithecus africanus, and Australopithecus sediba through the application of the validated entheses-based reconstruction of activity method. Using a comparative sample of later Homo and three great ape genera, we analyze the muscle attachment site proportions on the thumb, fifth ray, and third intermediate phalanx to gain insight into the habitual hand use of Australopithecus. We use a novel statistical procedure to account for the effects of interspecies variation in overall size and ray proportions. Our results highlight the importance of certain muscles of the first and fifth digits for humanlike hand use. In humans, these muscles are required for variable in-hand manipulation and are activated during stone-tool production. The entheses of A. sediba suggest muscle activation patterns consistent with a similar suite of habitual manual activities as in later Homo. In contrast, A. africanus and A. afarensis display a mosaic entheseal pattern that combines indications of both humanlike and apelike manipulation. Overall, these findings provide new evidence that some australopith species were already habitually engaging in humanlike manipulation, even if their manual dexterity was likely not as high as in later Homo.

2D shear wave elastography for the assessment of quadriceps entheses-a methodological study.

OBJECTIVE: To establish the scanning protocol for 2-dimensional shear wave elastography (SWE) on normal entheses by investigating the possible confounding factors that may increase the variability of measured elasticity. MATERIAL AND METHODS: 30 normal quadriceps entheses were scanned using SWE to compare the stiffness and coefficient variation by changing the ultrasonic coupling gel thickness, knee position, region of interest size, and scanning plane. RESULTS: No significant difference in median shear wave velocity (SWV) was observed in different coupling gel thicknesses. The median SWV was higher in the knee flexion position than in the extended position (p < 0.001). Increased knee flexion led to stiffer quadriceps enthesis and higher SWV (ρ = 0.8, p < 0.001). The median SWV was higher when the diameter region of interest was 4.0 mm than 2.0 mm (p = 0.001). The median SWV was higher in the transverse plane than in the longitudinal plane (p < 0.001). Strong correlation was found between SWV and the degree of the shear wave to muscle fiber direction (ρ = 0.8, p < 0.001). The coefficient variation was lower in a gel thickness of 2.5 cm, with an extended knee, a region of interest of 2.0 mm, and a longitudinal plane (p > 0.05). For interobserver reliability for the proposed protocol, the intraclass correlation coefficients was 0.763. CONCLUSION: In this study, we determined supine position with the knee extended; using 2.0 mm diameter region of interest and image acquisition at the longitudinal plane with thicker layer coupling gel seems most appropriate to reliably image healthy quadriceps entheses with SWE.

Architecture of head and neck soft tissues and associated entheses: An exploration of sexual dimorphism in, and population differences between, New Zealand and Thai individuals.

Understanding the musculoskeletal anatomy of soft tissues of the head and neck is important for surgical applications, biomechanical modelling and management of injuries, such as whiplash. Additionally, analysing sex and population differences in cervical anatomy can inform how biological sex and population variation may impact these anatomical applications. Although some muscles of the head and neck are well-studied, there is limited architectural information that also analyses sex and population variation, for many small cervical soft tissues (muscles and ligaments) and associated entheses (soft tissue attachment sites). Therefore, the aim of this study was to present architectural data (e.g., proximal and distal attachment sites, muscle physiological cross-sectional area, ligament mass, enthesis area) and analyse sex and population differences in soft tissues and entheses associated with sexually dimorphic landmarks on the cranium (nuchal crest and mastoid process) and clavicle (rhomboid fossa). Through the dissection and three-dimensional analysis of 20 donated cadavers from New Zealand (five males, five females; mean age 83 ± 8 years; range 67-93 years) and Thailand (five males, five females; 69 ± 13 years; range 44-87 years), the following soft tissues and their associated entheses were analysed: upper trapezius, semispinalis capitis and the nuchal ligament (nuchal crest); sternocleidomastoid, splenius capitis and longissimus capitis (mastoid process); the clavicular head of pectoralis major, subclavius, sternohyoid and the costoclavicular (rhomboid) ligament (rhomboid fossa). Findings indicate that although muscle, ligament and enthesis sizes were generally similar to previously published data, muscle size was smaller for six of the eight muscles in this study, with only the upper trapezius and subclavius demonstrating similar values to previous studies. Proximal and distal attachment sites were largely consistent with the current research. However, some individuals (six of 20) had proximal upper trapezius attachments on the cranium, with most attaching solely to the nuchal ligament, contrasting with existing literature, which often describes attachment to the occipital bone. With respect to sexual dimorphism, the Thai sample exhibited more sex differences in muscle size than the New Zealand sample, but for enthesis size (area), both samples had the same amount of statistically significant sex differences (5 of 10). Additionally, some significant population differences were found when comparing muscle and enthesis size data between the New Zealand and Thai samples. Despite these findings, no sex or population differences were found for ligament size (mass) in either group. This paper presents new architectural data for several understudied areas of the head and neck, as well as providing analyses on sex and population differences, two areas that have limited representation in anatomy.

Resolution of enthesitis by guselkumab and relationships to disease burden: 1-year results of two phase 3 psoriatic arthritis studies.

OBJECTIVE: To further characterize the effect of guselkumab, a selective IL-23p19-subunit inhibitor approved for PsA, on enthesitis and assess relationships between enthesitis resolution and patient status/outcomes. METHODS: Adults with active PsA despite standard therapies in the phase 3 DISCOVER-1 and DISCOVER-2 studies were randomized 1:1:1 to guselkumab 100 mg every 4 weeks (Q4W); guselkumab 100 mg at week 0, week 4, Q8W; or placebo through week 20 followed by guselkumab 100 mg Q4W. Independent assessors evaluated enthesitis using the Leeds Enthesitis Index (LEI; total score 0-6). Enthesitis findings through week 24 were pre-specified to be pooled across studies; post hoc and week 52 analyses also employed pooled data. RESULTS: Among 1118 randomized, treated patients in DISCOVER-1 and 2 who had ≥1 LEI site evaluated, 65% had enthesitis at baseline. These patients exhibited numerically more swollen and tender joints, systemic inflammation and impaired physical function than patients without enthesitis. Guselkumab Q4W and Q8W were superior to placebo in resolving pre-existing enthesitis at week 24 (45 and 50% vs 29%; both adjusted P = 0.0301). Enthesitis resolution rates continued to rise; 58% of guselkumab-randomized patients achieved resolution at week 52, including patients with mild (LEI = 1; 70-75%), moderate (LEI = 2; 69-73%) or severe (LEI = 3-6; 42-44%) enthesitis at baseline. Among guselkumab-randomized patients with resolved enthesitis at week 24, 42% achieved minimal disease activity at week 52, vs 17% of patients with unresolved enthesitis. CONCLUSION: Guselkumab resulted in higher proportions of PsA patients with resolved enthesitis by week 24, with maintenance of resolution rates through 1 year. As enthesitis confers greater disease burden, sustained resolution could portend better patient outcomes. CLINICAL TRIAL REGISTRATION: DISCOVER 1 (NCT03162796) and DISCOVER 2 (NCT03158285).

Biocultural evidence of precise manual activities in an Early Holocene individual of the high-altitude Peruvian Andes.

OBJECTIVES: Cuncaicha, a rockshelter site in the southern Peruvian Andes, has yielded archaeological evidence for human occupation at high elevation (4,480 masl) during the Terminal Pleistocene (12,500-11,200 cal BP), Early Holocene (9,500-9,000 cal BP), and later periods. One of the excavated human burials (Feature 15-06), corresponding to a middle-aged female dated to ~8,500 cal BP, exhibits skeletal osteoarthritic lesions previously proposed to reflect habitual loading and specialized crafting labor. Three small tools found in association with this burial are hypothesized to be associated with precise manual dexterity. MATERIALS AND METHODS: Here, we tested this functional hypothesis through the application of a novel multivariate methodology for the three-dimensional analysis of muscle attachment surfaces (entheses). This original approach has been recently validated on both lifelong-documented anthropological samples as well as experimental studies in nonhuman laboratory samples. Additionally, we analyzed the three-dimensional entheseal shape and resulting moment arms for muscle opponens pollicis. RESULTS: Results show that Cuncaicha individual 15-06 shows a distinctive entheseal pattern associated with habitual precision grasping via thumb-index finger coordination, which is shared exclusively with documented long-term precision workers from recent historical collections. The separate geometric morphometric analysis revealed that the individual's opponens pollicis enthesis presents a highly projecting morphology, which was found to strongly correlate with long joint moment arms (a fundamental component of force-producing capacity), closely resembling the form of Paleolithic hunter-gatherers from diverse geo-chronological contexts of Eurasia and North Africa. DISCUSSION: Overall, our findings provide the first biocultural evidence to confirm that the lifestyle of some of the earliest Andean inhabitants relied on habitual and forceful precision grasping tasks.

Ultrasound verified enthesophytes are associated with radiographic progression at entheses in psoriatic arthritis.

OBJECTIVES: The aim of this prospective study was to examine whether ultrasound or clinical abnormalities at enthesal sites predict radiographic progression at entheses in psoriatic arthritis (PsA). METHODS: Consecutive PsA patients were included and subjected to clinical and ultrasound assessments at 14 entheses at baseline, 6 and 12 months. Radiographs were performed at 0 and 12 months. By US, we investigated structural (erosions, osteophytes) and inflammatory changes [grey scale (0-32) and power Doppler (0-14, range global ultrasound score 0-140)], and radiographs were evaluated for enthesophytes and erosions (score range 0-56). Multivariate regression models were conducted to identify the possible association of clinical and ultrasound findings with radiographic progression. RESULTS: We examined 83 patients at baseline, of whom 43 (51.8%) had complete clinical, ultrasound and X-ray data. Twenty-four of 43 patients (55.8%) developed radiographic progression of entheses. These patients were younger (49.6 vs 59.3, P =0.005), had shorter disease duration (9.7 vs 17.9 years, P=0.015) and lower clinical disease activity at 6-months [disease activity in psoriatic arthritis (DAPSA) 6.7 vs 17.0, P=0.018] as compared with patients without progression. Non-progressors had higher ultrasound enthesophyte scores at baseline than progressors (20 vs 15, P<0.05). The multivariate regression analysis revealed that 48.6% of the variance of the X-ray score at 12-months follow-up (RegcoeffB = 0.827, P=0.000) could be explained by the baseline US enthesophyte score. CONCLUSION: Our data indicate that radiographic progression at entheses is linked with age, disease duration and ultrasound verified enthesophytes at baseline. No other ultrasound parameter predicted radiographic progression at entheses.

Biomechanical pathways of dentoalveolar fibrous joints in health and disease.

Spatial and temporal adaptations within periodontal tissues and their interfaces result from functional loads. Functional loads can be physiologic and/or pathologic in nature. The prolonged effect of these loads can alter the overall biomechanics of a dentoalveolar fibrous joint (dentoalveolar joint) by changing the form of the tooth root and its socket. This "sculpting" of the tooth root and alveolar bony socket is a consequence of several mechano-biological changes that occur within the periodontal complex of a load-bearing dentoalveolar joint. These include changes in biochemical expressions, structure, elemental composition, and mechanical properties of alveolar bone, the underlying tissues of the roots of teeth, and their interfaces. These physicochemical changes in tissues continue to prompt mechano-responsive biochemical activities at the attachment sites of periodontal ligament (soft) with bone (hard), and ligament with cementum (hard), which are the entheses of a load-bearing dentoalveolar joint. Forces at soft-hard tissue attachment sites between disparate materials with different stiffness values theoretically generate strain singularities or discontinuities. These discontinuities under prolonged functional loading increase the probability for failure to occur specifically at the enthesial zones. However, in a normal dentoalveolar joint, gradual stiffness gradients exist from ligament to bone, and from ligament to cementum. The gradual transitions in stiffness from softer ligament (lower stiffness) to harder bone or cementum (higher stiffness) or vice versa optimize tissue and interfacial strains. Optimization of tissue and ligament-enthesial physical and chemical properties facilitates transmission of cyclic forces of varying magnitudes and frequencies that collectively maintain the overall biomechanics of a dentoalveolar joint. The objectives of this review are 3-fold: (i) to illustrate physicochemical adaptations at the periodontal ligament entheses of a human periodontal complex affected by subgingival calculus; (ii) to demonstrate how to "program" the hallmarks of periodontitis in small-scale vertebrates in vivo to generate spatiotemporal maps of physicochemical adaptations in a diseased dentoalveolar joint; and (iii) to correlate dentoalveolar joint biomechanics in healthy and diseased states to spatiotemporal maps of physicochemical adaptations within respective periodontal tissues. This interdisciplinary approach demonstrates that physicochemical adaptations within periodontal tissues using the mechanics of materials (tissue mechanics), materials science (tissue composition), and mechano-biology (matrix molecules) can help explain the mechano-adaptation of dentoalveolar joints in normal and diseased functional states. Multiscale biomechanics and mechano-biology approaches can provide insights into the functional competence of a diseased relative to a normal dentoalveolar joint. Insights gathered from interdisciplinary and multiscale biomechanics approaches include the following: (i) physiologic loads related to chewing maintain a balance between mineral-forming and-resorbing biochemical cellular events, resulting in gradual stiffness gradients at the periodontal ligament entheses, and, in turn, sustain the overall biomechanics of a normal "healthy" dentoalveolar joint; (ii) pathologic loads resulting from tissue degradation and physical changes to the periodontal complex promote an abrupt stiffness gradient at the periodontal ligament entheses. The shift from gradual to an abrupt stiffness gradient could prompt a shift in the biochemical cascades, exacerbate mechano-responsive biochemical expressions at periodontal ligament entheses farther away from the site of insult, and culminate in joint degradation; (iii) sustained pathologic function on periodontally diseased joints exacerbates degradation of periodontal ligament entheses providing insights into "rescue therapy", such as the use of an adequate "mechanocal dose" to regain joint function; and (iv) spatiotemporal maps of changes in biochemical expressions, and physicochemical properties of strain-dominated affected sites, including the periodontal ligament entheses, can guide anatomy-specific therapeutics for tissue regeneration and/or disease control with the purpose of regaining dentoalveolar joint function. Modulation of occlusal loads could minimize disease progression and potentially assist in regaining functional attachment of ligament to bone and/or ligament to cementum of the dentoalveolar joint. Elucidating mechanisms that drive the breakdown of the functionally active periodontal complex burdened with microbes will provide the required critical insights into regenerative medicine and/or biomimetic approaches that would facilitate rescue/regain of dentoalveolar joint function.

Gendered division of labor in a Celtic community? A comparison of sex differences in entheseal changes and long bone shape and robusticity in the pre-Roman population of Verona (Italy, third-first century BC).

OBJECTIVES: The presence of a gendered subdivision of labor has been bioarchaeologically investigated in various prehistoric and historical contexts. Little is known, however, about the type of differences in daily activities characterizing men and women among the Celtic communities of Italy. The focus of the present study is the analysis of differences in patterns of entheseal changes (ECs) and long bone shape and robusticity between sexes among the Cenomani Gauls of Seminario Vescovile (SV-Verona, Italy, third-first century BC). MATERIALS AND METHODS: The sample includes 56 adult individuals (22 females and 34 males). Presence of ECs on nine bilateral postcranial attachment sites, and values of humeral and femoral shape and robusticity indices based on external measurements were compared between sexes by means of generalized linear models and Mann-Whitney tests. RESULTS: Results show a lack of difference between sexes in long bone shape and robusticity, and a higher incidence of upper and, especially, lower limb ECs in males. DISCUSSION: These results suggest the presence of sex-specific activities at SV mostly related to farming and differently influencing the considered variables. Also, this study suggests the relevance of a series of nonbiomechanical factors (developmental, hormonal, genetic, and methodological) when attempting biocultural reconstructions from osteoarchaeological samples.

The mechanical hypothesis of septal aperture formation tested in an early medieval population from Ostrów Lednicki (Poland).

The aetiology of septal aperture formation is still an open question. The influence of bone robusticity, osteoarthritis, osteoporosis, and the size and shape of ulnar processes has been discussed. Some researchers have shown that weaker muscles lead to greater joint hypermobility, the impingement of ulnar processes on the humeral lamina, and, consequently, septal aperture formation. Assuming this theory is correct, the question is whether flexion or extension or both play a role in septal lamina perforation. The aim of the study was to examine the mechanical hypothesis of septal aperture formation in samples of skeletal material derived from an early medieval cemetery in Ostrów Lednicki (Poland). A total of 136 pairs of bones (humeri and ulnae) were examined. Septal aperture was scored as present or absent. Entheseal changes in ulna were used as markers of activity patterns, especially involving elbow extension and flexion. Entheseal changes were assessed based on a three-point rating scale. A significant negative correlation between septal aperture and triceps muscles was noted in right bones in females (τ = -0.331) and in both sexes combined (τ = -0.322). The relationship between septal aperture and the brachialis muscle was positive but non-significant. This means that looser triceps lead to greater looseness of the elbow, greater protrusion of the olecranon process, and consequent septal aperture formation. Different results were obtained for the brachialis, which may suggest that forearm flexion does not significantly affect septal lamina perforation.

A three-dimensional digital microscopic investigation of entheseal changes as skeletal activity markers.

OBJECTIVES: The current article explores the effectiveness of entheseal changes (EC) as skeletal activity markers by testing the correlation between such changes and cross-sectional geometric (CSG) properties while controlling for the effect of age and body size. MATERIALS AND METHODS: The originality of the article lies in capturing EC in a continuous quantitative manner using three-dimensional microscopy. Roughness and bone resorption were recorded on Zones 1 and 2 of three humeral entheses (subscapularis, supraspinatus, and infraspinatus) in a documented sample of 29 male skeletons. RESULTS: Our analysis found that merely 5.91% of the partial correlations between EC and CSG properties were statistically significant. In addition, two unexpected patterns were identified, namely a higher number of significant correlations on the left side entheses compared to the right side ones, and a higher number of correlations between minimum roughness and CSG properties compared to mean and maximum roughness. DISCUSSION: These patterns are the inverse of what we would expect if activity had exerted an important effect on EC expression. Therefore, they support the lack of association between EC and habitual activity, even though various factors potentially affecting the above results are discussed.

Enthesitis: Much More Than Focal Insertion Point Inflammation.

PURPOSE OF REVIEW: Recognition of the importance of enthesitis as the pivotal pathological process underpinning spondyloarthropathies (SpA) has increased in recent years. Thus, we summarized the current knowledge on the pathogenic role of enthesitis on SpA shown by both animal models and human studies in vivo. RECENT FINDINGS: Experimental models have shown several SpA-like diseases that commence at entheses and are linked to nail disease as well as dactylitis, two important entheseal-associated conditions in humans. Frequently, enthesitis is not the primary outcome measure in studies of peripheral PsA and SpA although arguably it is the key parameter being indirectly assessed in spinal disease in ankylosing spondylitis. The use of different agents including JAK, IL-17, and IL-23 inhibitors contributes significantly to our understanding of enthesitis in terms of involved immune pathways. Enthesitis and enthesis organ inflammation may be the primary pathological process underlying SpA associated skeletal inflammation. Emergent studies are beginning to elucidate the molecular basis for this type of joint inflammatory response.

Diffuse idiopathic skeletal hyperostosis: Diagnostic, clinical, and paleopathological considerations.

Diffuse idiopathic skeletal hyperostosis (DISH) is a disease primarily affecting the spine. However, it is also associated with the ossification/calcification of tendon, ligament, and capsule insertions (entheses) occurring at multiple peripheral sites. The etiology of the condition is unknown, as the name suggests (diffuse idiopathic skeletal hyperostosis), although some correlations with diabetes mellitus, obesity, and age have been noted. Clinical diagnostic criteria have been adapted for paleopathological assessment of archeological skeletal remains, revealing some interesting patterns between monastic and lay populations; showing a higher incidence of DISH among individuals buried in monastic cemeteries. Although fascinating, the mechanisms behind this difference in prevalence are still not fully understood and have been attributed to the relatively richer diets of the monks and priests. The development of diagnostic criteria, where early stage cases of DISH can be identified as well as a better understanding of its causes, is paramount to the prevention of this potentially debilitating condition and perhaps this is where paleopathologists can assist. The use of dry bone rather than living patients for detailed assessment means that paleopathologists are less restricted by the techniques they can use in their investigations and the condition's occurrence in various archeological assemblages can provide interesting insights into its etiology. Clin. Anat. 29:870-877, 2016. © 2016 Wiley Periodicals, Inc.

Locomotor activity influences muscle architecture and bone growth but not muscle attachment site morphology.

The ability to make behavioural inferences from skeletal remains is critical to understanding the lifestyles and activities of past human populations and extinct animals. Muscle attachment site (enthesis) morphology has long been assumed to reflect muscle strength and activity during life, but little experimental evidence exists to directly link activity patterns with muscle development and the morphology of their attachments to the skeleton. We used a mouse model to experimentally test how the level and type of activity influences forelimb muscle architecture of spinodeltoideus, acromiodeltoideus, and superficial pectoralis, bone growth rate and gross morphology of their insertion sites. Over an 11-week period, we collected data on activity levels in one control group and two experimental activity groups (running, climbing) of female wild-type mice. Our results show that both activity type and level increased bone growth rates influenced muscle architecture, including differences in potential muscular excursion (fibre length) and potential force production (physiological cross-sectional area). However, despite significant influences on muscle architecture and bone development, activity had no observable effect on enthesis morphology. These results suggest that the gross morphology of entheses is less reliable than internal bone structure for making inferences about an individual's past behaviour.

Differentiating zones at periodontal ligament-bone and periodontal ligament-cementum entheses.

BACKGROUND AND OBJECTIVE: The structural and functional integrity of bone-periodontal ligament (PDL)-cementum complex stems from the load-bearing attachment sites (entheses) between soft (PDL) and hard (bone, cementum) tissues. These attachment sites are responsible for the maintenance of a bone-PDL-cementum complex biomechanical function. The objective was to investigate changes in spatiotemporal expression of key biomolecules in developing and functionally active entheses. MATERIAL AND METHODS: Multilabeling technique was performed on hemimandibles of 3 wk and 3 mo-old scleraxis-GFP transgenic mice for CD146, CD31, NG2, osterix and bone sialoprotein. Regions of dominant stretch within the PDL were evaluated by identifying directionality of collagen fibrils, PDL fibroblasts and PDL cell cytoskeleton. RESULTS: CD146+ cells adjacent to CD31+ vasculature were identified at PDL-bone enthesis. NG2+ cells were located at coronal bone-PDL and apical cementum-PDL entheses in the 3-wk-old group, but at 3 mo, NG2 was positive at the entheses of the apical region and alveolar crest. NG2 and osterix were colocalized at the osteoid and cementoid regions of the PDL-bone and PDL-cementum entheses. Bone sialoprotein was prominent at the apical region of 3-wk-old mice. The directionality of collagen fibers, fibroblasts and their cytoskeleton overlapped, except in the apical region of 3 wk. CONCLUSION: Colocalization of biomolecules at zones of the PDL adjacent to attachment sites may be essential for the formation of precementum and osteoid interfaces at a load-bearing bone-PDL-tooth fibrous joint. Biophysical cues resulting from development and function can regulate recruitment and differentiation of stem cells potentially from a vascular origin toward osteo- and cemento-blastic lineages at the PDL-bone and PDL-cementum entheses. Investigating the coupled effect of biophysical and biochemical stimuli leading to cell differentiation at the functional attachment sites is critical for developing regeneration strategies to enable functional reconstruction of the periodontal complex.

Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design.

The studies of entheses in bioarchaeology attempted to reconstruct the habitual physical activities of past populations. However, the studies of microarchitecture of the underlying bone are still lacking despite well-known potential of bone internal microarchitecture to reflect mechanical loading. It is unknown whether different morphological expressions of entheseal changes (ECs) correlate with the microstructural characteristics of the underlining bone. This study analyzed bone microstructural characteristics at the entheses. Our focus was on examining the possible successive nature of the three-stage scale of entheseal macroscopic changes by comparing EC scores with the microarchitectural features at the attachment sites. The study was based on the hypothesis that mechanical loading influences the microarchitecture of the bone at the attachment site. The bone samples were taken from 24 adult male skeletons from medieval cemeteries in Serbia, with different macroscopic expression score of EC. We evaluated the macroscopic and microscopic appearance of four entheses of the lower limbs (origin of the soleus muscle and the insertions of the adductor magnus, gluteus maximus, and iliopsoas muscles). The specimens were scanned using microcomputed tomography (Scanco µCT 40). Our data showed a lack of consistent correlation between stages of the macroscopic scoring systems with microarchitecture at the entheses, only cortical thickness was significantly different between EC stages. Analyzing relationship between trabecular and cortical bone microstructure we found correlations between cortical and trabecular variables only in Stage C. Results of our study suggest that macroscopic EC might not represent distinct successive phases in bone adaptation to mechanical loading.

Evaluating the efficiency of different recording protocols for entheseal changes in regards to expressing activity patterns using archival data and cross-sectional geometric properties.

OBJECTIVES: In the past decade there have been extensive discussions on the potential utility of entheseal changes (EC) as activity markers. Nevertheless, no study to date has compared different EC recording protocols with respect to their correlation to activity patterns. MATERIALS AND METHODS: This article records changes on fibrocartilaginous entheses of the upper limbs of 90 male skeletons from the documented Athens Collection using the Hawkey and Merbs (Int J Osteoarchaeol 5 (1995) 324-338), Mariotti et al. (Collegium Antropol 28 (2004) 145-159), and Villotte et al. (Am J Phys Anthropol 142 (2010) 224-234) recording schemes in order to determine which one exhibits the highest correlation with activity. Activity is assessed by means of the recorded profession of each individual, as well as employing cross-sectional geometric properties. Generalized Linear Models are used to explore the impact of age, body mass, and activity on EC expression. RESULTS: Our results agree with previous studies that age is the primary factor determining EC, whereas body mass is the second most influential factor. In contrast, activity in the form of profession or cross-sectional geometry rarely showed a significant correlation to EC expression and no clear pattern could be discerned irrespective of the recording technique. However, bilateral differences in the impact of age and body mass in EC expression were traced and may relate to activity patterns. CONCLUSIONS: The differences found in the bilateral impact of age and body mass highlight the fact that the activity patterns of the individuals under examination must play an underlying role to EC expression, though current recording schemes for EC do not capture this, rendering further work in the direction of developing more elaborate recording standards imperative.

The use of generalized linear models and generalized estimating equations in bioarchaeological studies.

The current article explores whether the application of generalized linear models (GLM) and generalized estimating equations (GEE) can be used in place of conventional statistical analyses in the study of ordinal data that code an underlying continuous variable, like entheseal changes. The analysis of artificial data and ordinal data expressing entheseal changes in archaeological North African populations gave the following results. Parametric and nonparametric tests give convergent results particularly for P values <0.1, irrespective of whether the underlying variable is normally distributed or not under the condition that the samples involved in the tests exhibit approximately equal sizes. If this prerequisite is valid and provided that the samples are of equal variances, analysis of covariance may be adopted. GLM are not subject to constraints and give results that converge to those obtained from all nonparametric tests. Therefore, they can be used instead of traditional tests as they give the same amount of information as them, but with the advantage of allowing the study of the simultaneous impact of multiple predictors and their interactions and the modeling of the experimental data. However, GLM should be replaced by GEE for the study of bilateral asymmetry and in general when paired samples are tested, because GEE are appropriate for correlated data.

Enthesopathies - Mechanical, inflammatory or both?

Entheses have the challenging task of transferring biomechanical forces between tendon and bone, two tissues that differ greatly in composition and mechanical properties. Consequently, entheses are adapted to withstand these forces through continuous repair mechanisms. Locally specialized cells (mechanosensitive tenocytes) are crucial in the repair, physiologically triggering biochemical processes to maintain hemostasis. When repetitive forces cause "material fatigue," or trauma exceeds the entheses' repair capacity, structural changes occur, and patients become symptomatic. Clinical assessment of enthesopathies mainly depends on subjective reports by the patient and lacks specificity, especially in patients with central sensitization syndromes. Ultrasonography has been increasingly used to improve the diagnosis of enthesopathies. In this article, the literature on how biomechanical forces lead to entheseal inflammation, including factors contributing to differentiation into a "clinical enthesitis" state and the value of ultrasound to diagnose enthesopathies will be reviewed, as well as providing clues to overcome the pitfalls of imaging.

Entheseal changes and activity patterns in southern African hunter-gatherer/herders from the Holocene.

OBJECTIVES: Activity patterns and lifeways in southern African hunter-gatherer/herders (sAHGH) during the Holocene were dynamic, with subsistence activities and mobility varying through space and time. In this study, spatial and temporal variations in entheseal changes (ECs) are assessed as physical activity markers in sAHGH from the Holocene. METHODS: The Coimbra method was used to assess fibrocartilaginous ECs in the upper and lower limbs of 118 sAHGH from the Holocene. Descriptive statistics and generalized estimating equations were used to explore the association between ECs, sex, age, ecological biomes, and temporality. RESULTS: A total of 118 individuals were sampled, comprising 67 males, and 42 females, mostly from the fynbos (59/118), forest (30/118) and succulent karoo biomes (16/118). ECs were identified in 94% of the sample. Interobserver scoring suggests our findings are likely to underrepresent the extent of EC score differences in sAHGH. Findings indicate a complex pattern of physical activity in sAHGH with differences attributable to regional ecology rather than age or sex. More prominent ECs were identified in individuals from the forest biome, relative to the fynbos and succulent karoo biomes. These were consistent with resource search and processing costs, and terrain differences in these ecozones. ECs were only detected temporally relative to the infiltration of pastoralism (at 2000 BP) when the data were stratified by ecological biome. DISCUSSION: This study provides evidence that regional ecology plays a central role in driving activity patterns regardless of social or cultural organization. Ecological biomes provide a gradient along which the temporal impact of resource limitations on human biology, activity patterns and sociocultural behaviors can be studied.