Intermittent low-dose injections of parathyroid hormone (PTH) have been reported to exert bone anabolic effects and to promote fracture healing. As an important proangiogenic cytokine, vascular endothelial growth factor (VEGF) is secreted by bone marrow mesenchymal stem cells (BMSCs) and osteoblasts, and serves a crucial regulatory role in the process of vascular development and regeneration. To investigate whether lack of endogenous PTH causes reduced angiogenic capacity and thereby delays the process of fracture healing by downregulating the VEGF signaling pathway, a PTH knockout (PTHKO) mouse fracture model was generated. Fracture healing was observed using X-ray and micro-computerized tomography. Bone anabolic and angiogenic markers were analyzed by immunohistochemistry and western blot analysis. The expression levels of VEGF and associated signaling pathways in murine BMSC-derived osteoblasts were measured by quantitative polymerase chain reaction and western blot analysis. The expression levels of protein kinase A (PKA), phosphorylated-serine/threonine protein kinase (pAKT), hypoxia-inducible factor-1 alpha (HIF1 alpha) and VEGF were significantly decreased in BMSC-derived osteoblasts from PTHKO mice. In addition, positive platelet endothelial cell adhesion molecule staining was reduced in PTHKO mice, as determined by immunohistochemistry. The expression levels of HIF1 alpha, VEGF, runt-related transcription factor 2, osteocalcin and alkaline phosphatase were also decreased in PTHKO mice, and fracture healing was delayed. In conclusion, lack of endogenous PTH may reduce VEGF expression in BMSC-derived osteoblasts by downregulating the activity of the PKA/pAKT/HIF1 alpha/VEGF pathway, thus affecting endochondral bone formation by causing a reduction in angiogenesis and osteogenesis, ultimately leading to delayed fracture healing.

Based on previous findings that cyclooxygenase-2 (COX-2) is a critical molecule in chondrocyte differentiation and skeletal repair, we hypothesized that COX-2 deficiency or inhibition affects the ossification of vertebral endplates (VEP) and degeneration of intervertebral discs (IVD) and thus is involved in the pathogenesis of low back pain (LBP). We aimed to delineate the COX-2 working mechanism and its interacting molecules, and to explore the effect of NSAIDs and selective COX-2 inhibitor on degenerative spinal diseases. Here, lumbar spinal samples harvested from Cox-2 mutant (Cox-2-/-) and wild type (WT) mice were used for histological examinations. Nucleus pulposus (NP) cells isolated from rat were treated with PGE-2. Mouse endplate chondrocytes (mEC) isolated from mice were treated with a recombinant sonic hedgehog (Shh) protein. A mouse IVD organ culture system was established and treated COX-2 inhibitor Celecoxib. Human lumbar endplate chondrocytes were cultured and treated with Celecoxib. Immunohistochemical (IHC) studies were done in the human and mouse VEP samples. Radiographic and histological examinations revealed delayed VEP ossification in Cox-2-/- mice compared to WT ones. Decreased PGE-2 expression was found to promote Shh expression in rat NP cells, while Shh increased noggin expression in mEC. IHC showed that noggin expression was increased while pSmad1 expression decreased in the VEP of Cox-2-/- mice. Human VEP samples from patients with severe IVD degeneration showed decreased expression of Shh and noggin and increased expression of COX-2 and pSmad1 compared with milder cases. In cultured mouse IVDs and human endplate chondrocytes, Celecoxib enhanced expression of Shh and noggin and decreased Smad1 phosphorylation. In conclusion, COX-2/PGE-2 axis plays an important role in VEP ossification and IVD degeneration through crosstalk with Shh and BMP signaling pathways. These findings may facilitate clinical use of COX-2 inhibitor to prevent LBP progression.

mTOR is a valuable oncotarget for osteosarcoma. The anti-osteosarcoma activity by a novel mTOR kinase inhibitor, CZ415, was evaluated. We demonstrated that CZ415 potently inhibited survival and proliferation of known osteosarcoma cell lines (U2OS, MG-63 and SaOs2), and primary human osteosarcoma cells. Further, CZ415 provoked apoptosis and disrupted cell cycle progression in osteosarcoma cells. CZ415 treatment in osteosarcoma cells concurrently blocked mTORC1 and mTORC2 activation. Intriguingly, ERK-MAPK activation could be a major resistance factor of CZ415. ERK inhibition (by MEK162/U0126) or knockdown (by targeted ERK1/2 shRNAs) dramatically sensitized CZ415-induced osteosarcoma cell apoptosis. In vivo, CZ415 oral administration efficiently inhibited U2OS tumor growth in mice. Its activity was further potentiated with co-administration of MEK162. Collectively, we demonstrate that ERK inhibition sensitizes CZ415-induced anti-osteosarcoma activity in vitro and in vivo. CZ415 could be further tested as a promising anti-osteosarcoma agent, alone or in combination of ERK inhibition.

Osteoporosis is a common problem in aged people and those with related diseases, such as inflammatory bowel diseases. Deregulation of vitamin D metabolism plays a role in the pathogenesis of osteoporosis. Micro RNA (miR) can regulate cytokine expression in cells. This study test a hypothesis that inflammatory cytokine interleukin (IL)-13 increases miR-19a to compromise cyp27b1 (a vitamin D hydroxylase) in peripheral CD14+ cells. Bone mineral density of L2–L4 was measured in 20 patients with ulcerative colitis (UC) and 20 healthy subjects. Peripheral CD14+ cells were isolated from healthy people and patients with UC. Expression of cyp27b1 by CD14+ cells was analyzed in the presence or absence of IL-13 in the culture. We observed that bone mineral density (BMD) in UC patients was significantly lower than healthy subjects. The BMD is negatively correlated with miR-19a in peripheral CD14+ cells. MiR-19a in peripheral CD14+ cell was correlated with serum IL-13 in UC patients. Expression of cyp27b1 in peripheral CD14+ cells was correlated with miR-19a and serum IL-13 in UC patients. IL-13 suppressed cyp27b1 expression in CD14+ cells. IL-13 increased expression of miR-19a in CD14+ cells. IL-13 suppresses cyp27b1 expression in peripheral CD14+ cells via up regulating miR-19a expression. J. Cell. Biochem. 118: 376–381, 2017. © 2016 Wiley Periodicals, Inc.

STUDY DESIGN:Technical note. OBJECTIVE:To determine the correlation between the high-intensity lesions observed on T2-weighted magnetic resonance images (T2W MRI) and the cervical dynamic characteristics of patients with cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA:Intramedullary high signal intensity is frequently observed on T2W MRI of CSM patients and represents pathologic changes in the spinal cord. However, few studies have attempted to identify the effects on cervical dynamics associated with such changes in MRI signals. METHODS:This study included 71 CSM patients who were admitted to our hospital between May, 2009 and May, 2012 (44 men, 27 women; average age, 52.5±11.7 y). They were divided into 3 groups depending on T2W MRI data: group 1, no hyperintensity; group 2, slight hyperintensity; and group 3, bright hyperintensity. The Cobb angle on cervical flexion-extension radiographs was measured as a parameter of cervical spine dynamics. RESULTS:Total hyperflexion, hyperextension curvature, range of movement (ROM), and segmental hyperflexion curvature did not differ among the groups (P>0.05). Segmental hyperextension curvature and ROM were greater in groups 2 and 3 than in group 1 (P<0.05) but did not differ significantly between groups 2 and 3 (P>0.05). CONCLUSIONS:Increased segmental hyperextension curvature (≥10 degrees) and ROM are risk factors for high-intensity lesions on T2W MRI in CSM patients.

Study Design: Literature review and meta-analysis.Objective: To perform a systematic review and meta-analysis of risk factors for new osteoporotic vertebral compression fracture (VCF) after vertebroplasty.Summary of Background Data: New osteoporotic VCF is one of the serious complications of vertebroplasty, and it is important to investigate the risk factors for such VCFs. The risk factors for new VCFs reported so far remain controversial because of limited data and lack of uniform measurements and evaluation.Methods: We searched the electronic database of PubMed for case-control studies about the risk of new osteoporotic VCFs after vertebroplasty.Results: A total of 116 studies were identified, of which 16 studies including 559 cases and 1736 controls met the inclusion criteria. The significant risk factors for new VCFs were low bone mineral density [BMD; standardized mean difference (SMD), -0.73; 95% confidence interval (CI), -1.26 to -0.20], low body mass index (BMI; SMD, -0.30; 95% CI, -0.51 to -0.10), and intradiscal cement leakage [ odds ratio (OR), 2.13; 95% CI, 1.40-2.36]. The significant risk factors for new VCFs adjacent to the treated VCF were low BMD (SMD, -0.43; 95% CI, -0.76 to -0.09), low BMI (SMD, -0.52; 95% CI, -0.81 to -0.22), and intradiscal cement leakage (OR, 2.61; 95% CI, 1.63-4.17). Low BMD, low BMI, intradiscal cement leakage, cement volume, surgical approach, age, sex, and thoracolumbar junction fracture were all not significant risk factors for new VCFs away from the original VCF. Only one study reported dynamic characteristics as risk factors for new VCFs.Conclusions: The results of this meta-analysis strongly suggested that patients with low BMD, low BMI, and intradiscal cement leakage were at high risk for new VCFs after vertebroplasty, and risk-reduction options should be considered for such patients.