Non-neuronal Role of Acetylcholinesterase in Bone Development and Degeneration.

Acetylcholinesterase (AChE), an enzyme catalyzing the degradation of acetylcholine, plays an important suppressive role in the cholinergic regulation by terminating the action of acetylcholine. The expression of acetylcholinesterase and other cholinergic components is not restricted to only brain and nerve tissues but can also be found in non-neuronal tissues like the immune system and bone tissue. Primary identification of these components has been achieved. However, the information about their specific functions and underlying molecular mechanisms in bone remains scattered. Here, the physiological process of bone development, homeostasis, and degeneration are introduced. Next, the cholinergic system and its expression in bone tissue is documented. Among them, special attention goes to AChE, as the structure of this enzyme suggests diverse binding affinities, enabled by a peripheral site and a catalytic site. The peripheral site supports the non-enzymatic function of AChE in non-neuronal systems. Based on recent studies, the non-neuronal roles of acetylcholinesterase, both enzymatically and non-enzymatically, in bone development, homeostasis and degeneration are summarized briefly together with potential mechanisms to support these functions. We conclude that AChE may be a potential therapeutic target for bone diseases like osteoporosis.

Expression of adiponectin in the subchondral bone of lumbar facet joints with different degrees of degeneration.

BACKGROUND: Osteoarthritis research has been most commonly performed in the setting of the articular cartilage of the knee. To the best of our knowledge, no studies have evaluated the role of adiponectin in osteoarthritis of the lumbar facet joint (FJOA). Therefore, in this study, we explored whether adiponectin was expressed in the lumbar facet joints and evaluated the role of adiponectin in FJOA. METHODS: We enrolled patients who underwent lumbar computed tomography (CT) and magnetic resonance imaging (MRI) at the Orthopedic Department of the First Affiliated Hospital of Nanchang from May 2015 to June 2016. Lumbar facet joints were obtained from 135 patients at the time of lumbar fusion surgery and divided into three groups according to the Weishaupt grade. Cytokine levels in the subchondral bones were evaluated by enzyme-linked immunosorbent assays (ELISAs), and adiponectin levels were determined by immunohistochemistry, western blotting, and quantitative polymerase chain reaction (qPCR). RESULTS: By ELISA, adiponectin levels were examined in the subchondral bone for lumbar facet joint, and adiponectin was found to be negatively correlated with BMI in 52 patients (p < 0.001, r = -0.861). By immunohistochemistry analysis, adiponectin was found to be expressed in the subchondral bone of the lumbar facet, whereas the cartilage area was negative for adiponectin expression. Immunostaining intensity and area was related to the degeneration of the lumbar facet joint, and, in our research, considerably decreased staining intensity and area were observed in more severely degenerated lumbar facet joints. Furthermore, the expression of adiponectin was also reduced in degenerated lumbar facet joints, and the level of decline corresponded to degeneration detected by western blotting and qPCR analysis (n = 27, p < 0.0001). CONCLUSIONS: Adiponectin expression was observed in the subchondral bone of the lumbar facet joint and decreased as the degree of degeneration increased. Thus, the results of this study provide new insights into the relationship between adiponectin and osteoarthritis.

3D superimposition and understanding temporomandibular joint arthritis.

OBJECTIVES: To investigate the 3D morphological variations in 169 temporomandibular ioint (TMJ) condyles, using novel imaging statistical modeling approaches. SETTING AND SAMPLE POPULATION: The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Cone beam CT scans were acquired from 69 subjects with long-term TMJ osteoarthritis (OA, mean age 39.1±15.7 years), 15 subjects at initial consult diagnosis of OA (mean age 44.9±14.8 years), and seven healthy controls (mean age 43±12.4 years). MATERIALS AND METHODS: 3D surface models of the condyles were constructed, and homologous correspondent points on each model were established. The statistical framework included Direction-Projection-Permutation (DiProPerm) for testing statistical significance of the differences between healthy controls and the OA groups determined by clinical and radiographic diagnoses. RESULTS: Condylar morphology in OA and healthy subjects varied widely with categorization from mild to severe bone degeneration or overgrowth. DiProPerm statistics supported a significant difference between the healthy control group and the initial diagnosis of OA group (t=6.6, empirical p-value=0.006) and between healthy and long-term diagnosis of OA group (t=7.2, empirical p-value=0). Compared with healthy controls, the average condyle in OA subjects was significantly smaller in all dimensions, except its anterior surface, even in subjects with initial diagnosis of OA. CONCLUSION: This new statistical modeling of condylar morphology allows the development of more targeted classifications of this condition than previously possible.

Estimating age of mature adults from the degeneration of the sternal end of the clavicle.

The sternal end of the clavicle has been illustrated to be useful in aging young adults, however, no studies have investigated what age-related changes occur to the sternal end post epiphyseal fusion. In this study, three morphological features (i.e., surface topography, porosity, and osteophyte formation) were examined and scored using 564 clavicles of individuals of European ancestry (n = 318 males; n = 246 females), with known ages of 40+ years, from four documented skeletal collections: Hamann-Todd, Pretoria, St. Bride's, and Coimbra. An ordinal scoring method was developed for each of the three traits. Surface topography showed the strongest correlation with age, and composite scores (formed by summing the three separate trait scores) indicated progressive degeneration of the surface with increasing chronological age. Linear regression analyses were performed on the trait scores to produce pooled-sample age estimation equations. Blind tests of the composite score method and regression formulae on 56 individuals, aged 40+ years, from Christ Church Spitalfields, suggest accuracies of 96.4% for both methods. These preliminary results display the first evidence of the utility of the sternal end of the clavicle in aging older adult individuals. However, in the current format, these criteria should only be applied to individuals already identified as over 40 years in order to refine the age ranges used for advanced age. These findings do suggest the sternal end of the clavicle has potential to aid age estimates beyond the traditional "mature adult" age category (i.e., 46+ years), and provides several suggestions for future research.