Age-dependent role of SIRT6 in jawbone via regulating senescence and autophagy of bone marrow stromal cells

AbstractAge-related jawbone loss directly impact the function of oral cavity resulted from tooth loss, implant failure, and jaw fracture. Numerous evidences show that age-related senescence of bone marrow stromal cells (BMSCs) play a critical role in bone loss, but little attention has been paid to jawbone. Here, we delineated the critical role of sirtuin family protein 6 (SIRT6) in senescence, autophagy, and osteogenesis of BMSCs from jawbones. Radiography analysis showed less jawbone quality in elderly than young people. We also showed that SIRT6 expression decreased in bone tissue and BMSCs from the elderly by immunochemical staining. BMSCs from the elderly exhibited decreased osteogenic differentiation and inclined senescence which these phenotypes could be simulated by SIRT6 knockdown. Furthermore, accompanied with the inhibition of SIRT6, the autophagy level and ostogenesis of BMSCs was also decreased. However, using rapamycin, an autophagy activator, could rescue these adverse effects of BMSCs caused by SIRT6 inhibition. Mechanistically, SIRT6 regulated the autophagy and osteogenesis of BMSCs by activating AKT-mTOR pathway, at least in part. Finally, a decreased jawbone quality was shown in SIRT6 haploinsufficiency mice by Wnt1 specific tissue knockdown (Wnt1-Cre;SIRT6fl/+) model. Taken together, our data revealed that SIRT6 adjusted senescence and osteogenesis of BMSCs via altering autophagy level, and associated with age-related bone loss. SIRT6 could be as a promisi...
Source: Journal of Molecular Histology - Category: Laboratory Medicine Source Type: research

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A 44-year-old woman with a history of hypertension and partial gastrectomy presented to the emergency department with low thoracic back pain of 2  days' duration without red flag symptoms. The physical examination was significant for point tenderness to palpation in the lower thoracic spine without overlying skin changes or neurologic symptoms. Considering her large body habitus and history of gastrectomy, a thoracic radiograph was obtained to rule out compression fracture due to osteoporosis (Figure 1).
Source: The Journal of Emergency Medicine - Category: Emergency Medicine Authors: Tags: Visual Diagnosis in Emergency Medicine Source Type: research
CONCLUSIONS: A high index of suspicion is needed to diagnose sacral insufficiency fracture after LS arthrodesis. A trial of conservative management is reasonable for select patients; potential surgical indications include refractory pain, neurological deficit, fracture nonunion with anterolisthesis or kyphotic angulation, L5-S1 pseudarthrosis, and spinopelvic malalignment. Lumbopelvic fixation with iliac screws may be effective salvage treatment to allow fracture healing and symptom improvement. High-risk patients may benefit from prophylactic lumbopelvic fixation at the time of index LS arthrodesis. PMID: 32217798 [P...
Source: Journal of Neurosurgery.Spine - Category: Neurosurgery Authors: Tags: J Neurosurg Spine Source Type: research
AbstractPurpose of ReviewThis review discusses imaging modalities for fracture repair assessment, with an emphasis on pragmatic clinical and translational use, best practices for implementation, and challenges and opportunities for continuing research.Recent FindingsSemiquantitative radiographic union scoring remains the clinical gold standard, but has questionable reliability as a surrogate indicator of structural bone healing, particularly in early-stage, complex, or compromised healing scenarios. Alternatively, computed tomography (CT) scanning enables quantitative assessment of callus morphometry and mechanics through ...
Source: Current Osteoporosis Reports - Category: Orthopaedics Source Type: research
Authors: Li J, Karim MA, Che H, Geng Q, Miao D Abstract To investigate whether p16 deletion can prevent osteoporosis caused by estrogen deficiency, we first confirmed that p16 protein expression levels were significantly up-regulated in bony tissue of ovariectomized (OVX) wild-type mice. Eight-week-old wild-type and p16-/- mice were then sham-operated or bilateral OVX. After 12 weeks, the bone phenotypes of all models were analyzed by radiography, micro-computed tomography, histology, immunohistochemistry, and molecular biology. The results showed that p16 deficiency could rescue OVX-induced osteoporosis by signifi...
Source: American Journal of Translational Research - Category: Research Tags: Am J Transl Res Source Type: research
This study aimed to investigate whether USF concomitant with low-energy DRF was associated with the bone mineral status and the degree of radiographically observed pretreatment radius displacement in Japanese adults above 50  years of age.MethodsThe study subjects were 45 (44 female, 1 male) consecutive patients aged>  50 years with DRF caused by falls from June 2015 to May 2016. Fractures due to high-energy injuries were excluded. Patients were divided into two groups according to the presence or absence of USF. Radius displacement was assessed on anteroposterior and lateral radiographs by measuring ul...
Source: Archives of Orthopaedic and Trauma Surgery - Category: Orthopaedics Source Type: research
AbstractPurpose of ReviewTo summarize the bone findings, mainly bone mass and fracture risk, in Ehlers –Danlos syndromes (EDS).Recent FindingsLow bone mineral density and fractures seem to be frequent in some of the rare EDS types (kyphoscoliotic, arthrochalasia, spondylodysplastic, and classic-like EDS). For the more prevalent hypermobile and classic EDS types, some case –control studies found mildly decreased bone mineral density, but it was not clear that fracture rates were increased. Nevertheless, abnormalities in vertebral shape seem to be common in classical and hypermobile EDS types. In a cohort of indi...
Source: Current Osteoporosis Reports - Category: Orthopaedics Source Type: research
Objective: Immunological abnormalities, the resulting endocrinopathies and their treatments may impact bone health in patients with autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED, APS1). The aim of the present study was to describe skeletal characteristics in patients with APECED and the prevalence and risk factors of compromised bone health.Patients and methods: We performed a cross-sectional study on 44 patients (27 females) with APECED and 82 age-, gender- and ethnicity-matched control subjects (54 females). We determined the prevalence of osteoporosis by dual-energy X-ray absorptiome...
Source: Frontiers in Endocrinology - Category: Endocrinology Source Type: research
ConclusionsIn contrast to the well ‐established association between black race and knee or hip OA, odds of hand OA are lower in black versus nonblack subjects, which is not mediated by known hand OA risk factors. Future mechanistic works are warranted to determine the mediating protective factors for hand OA among the black subject s.
Source: Arthritis and Rheumatology - Category: Rheumatology Authors: Tags: FULL LENGTH Source Type: research
Abstract BACKGROUND: The concurrent presence of sarcopenia and osteoporosis may enhance fracture risk. AIM: To evaluate the association between sarcopenia, osteoporosis, or the concurrent presence of both the conditions (osteosarcopenia) and the burden (number and severity) of vertebral fractures in women with hip fracture. DESIGN: Cross-sectional study. POPULATION: We studied 350 women with subacute hip fracture. METHODS: Lateral radiographs of the spine were taken 18.2±4.5 days after fracture occurrence and the spine deformity index (SDI) was calculated. Body composition was assessed b...
Source: European Journal of Physical and Rehabilitation Medicine - Category: Rehabilitation Authors: Tags: Eur J Phys Rehabil Med Source Type: research
Authors: Tobert DG, Schwab JH Abstract Vertebral compression fractures commonly occur as sequelae to osteoporosis, malignancy, infection, or trauma. Although all compression fractures have an underlying pathology, the term pathologic vertebral compression fracture (pVCF) is traditionally reserved for fractures that result from primary or metastatic spine tumors. Discriminating a pVCF from osteoporotic vertebral compression fractures is important because the subsequent diagnostic workup and therapeutic plan differ substantially between the two etiologies. A carefully obtained history inquiring about high-risk sympto...
Source: Instructional Course Lectures - Category: Orthopaedics Tags: Instr Course Lect Source Type: research
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