The tumor suppressive role of TIMP3 in the human osteosarcoma cells.

BACKGROUND: Tissue inhibitor of metalloproteinase 3 (TIMP3) regulates a variety of cellular activities such as proliferation, viability, apoptosis, and motility. Functional loss of TIMP3 is reported in several human cancers. However, its role in osteosarcoma (OS) remains largely unclear. METHODS: In this study, we explored the mechanism underlying the modulation of TIMP3 in the growth and aggressiveness of U2OS and 143B human OS cells at both cellular and molecular levels. RESULTS: Our results show that overexpression of TIMP3 inhibits endogenous MMP activity and represses a series of oncogenic phenotypes of tumor cells independent of MMP inhibition, including reduced proliferation and survival, induced apoptosis, as well as improved sensitivity of tumor cells in response to cisplatin chemotherapy. TIMP3 overexpression also suppresses tumor cell invasion via its MMP inhibitory capacity. Importantly, TIMP3 modulates tumor cell oncogenesis via its induction of PTEN and subsequent inactivation of the PI3K/AKT pathway. CONCLUSION: Our results suggest that TIMP3 is an oncosuppressor in human OS cells. Reactivation of TIMP3 function may be considered as a potential therapy for the treatment of this bone cancer.

The NF-κB pathway is critically implicated in the oncogenic phenotype of human osteosarcoma cells.

NF-κB is activated in a variety of human cancers. However, its role in osteosarcoma (OS) remains unknown. Here, we have elucidated the implication of NF-κB in the oncogenic phenotype of OS tumor cells. We reported that activation of NF-κB was a common event in the human OS. Inhibition of NF-κB using inhibitor Bay 11-7085 repressed proliferation, survival, migration, and invasion but increased apoptosis in 143B and MG63 OS cells, indicating that NF-κB is critically implicated in the oncogenesis of OS. Notably, Bay 11-7085 not only inactivated NF-κB but also reduced the phosphorylation of AKT via its induction of PTEN, suggesting the existence of a novel NF-κB/PTEN/PI3K/AKT axis. In vivo, Bay 11-7085 suppressed tumor growth in the bone by targeting NF-κB and AKT. Interestingly, combined treatment with Bay 11-7085 and the PI3K inhibitor, LY294002, triggered an augmented antitumor effect. Our results demonstrate that NF-κB potentiates the growth and aggressiveness of OS. Pharmacological inhibition of NF-κB represents a promising therapy for the treatment of OS.

Critical implication of the PTEN/PI3K/AKT pathway during BMP2-induced heterotopic ossification.

Heterotopic ossification (HO) is characterized by extraskeletal ossification in soft tissue. Thus far, there is a lack of effective drug therapy against HO. Loss of PTEN in osteoblasts has been reported to accumulate bone mass in skeletal development and promote fracture healing in association with the activation of the PI3K/AKT pathway. However, the role of the PTEN/PI3K/AKT signaling in HO pathogenesis remains unknown. The present study investigated the implication of this pathway during BMP2­induced osteogenic differentiation and ectopic bone formation. It was shown that overexpression of PTEN inhibited proliferation but stimulated apoptosis in mesenchymal pluripotent C3H10T1/2 cells. PTEN also inhibited BMP2­induced osteoblast differentiation, whereas BMP2 repressed PTEN expression and subsequently activated PI3K/AKT. The PI3K inhibitor, LY294002, blocked BMP2­induced osteoblastogenesis, suggesting that the PI3K/AKT pathway is critically required for BMP2 to initiate osteoblastogenesis. In vivo, implantation of BMP2 in muscle induced ectopic endochondral ossification. Strikingly, this bone­forming capacity was notably suppressed by the PI3K inhibitor LY294002. Hence, the results of the present study demonstrated that the PI3K/AKT signaling activity is indispensable for BMP2 to induce ectopic new bone. Targeting the PI3K/AKT pathway using inhibitor(s) may represent a potential molecular therapy for the treatment against HO.

Dkk1 acts as a negative regulator in the osteogenic differentiation of the posterior longitudinal ligament cells.

Ossification of the posterior longitudinal ligament (OPLL) is a spinal disorder characterized by progressive ectopic bone formation in the PLL of the spine. Dickkopf-1 (Dkk1) is a secreted inhibitor of the Wnt pathway that negatively regulates bone formation during skeletal development. However, whether Dkk1 impacts the pathogenesis of OPLL has not been reported. This study is to investigate the role of Dkk1 in the development of OPLL. Our results show that the serum levels of Dkk1 are decreased in OPLL patients compared with non-OPLL controls. The expression of Dkk1 is also reduced in OPLL ligament cells. Downregulation of Dkk1 in ligament cells is associated with activation of the Wnt/ß-catenin signaling, as indicated by stabilized ß-catenin and increased T-cell factor-dependent transcriptional activity. Functionally, Dkk1 exerts a growth-inhibitory effect by repressing proliferation but promoting apoptosis of ligament cells. Dkk1 also suppresses bone morphogenetic protein 2-induced entire osteogenic differentiation of ligament cells, and this suppression is mediated via its inhibition of the Wnt pathway. Our results demonstrate for the first time that Dkk1 acts as an important negative regulator in the ossification of the PLL. Targeting the Wnt pathway using Dkk1 may represent a potential therapeutic strategy for the treatment of OPLL.

Circular RNA circ_0011269 sponges miR-122 to regulate RUNX2 expression and promotes osteoporosis progression.

Circular RNAs (circRNAs) are a novel class of noncoding RNAs that are widely expressed in human disease. However, circRNAs expression profile and potential mechanism in osteoporosis pathogenesis remain to be further studied. In the present study, a total of 69 circRNAs were identified to be abnormally expressed in osteoporosis patient samples by microarray and bioinformatics analyses. We found that circ_0011269 was notably downregulated in osteoporosis (fold change, 3.94). By means of miRanda algorithm, we constructed the interaction network of circ_0011269-miRNAs in osteoporosis based on target binding and miR-122 was enrolled in the network. Dual-luciferase reporter assay verified the target relationship of miR-122 and circ_0011269/RUNX2. The expression of circ_0011269 and RUNX2 were gradually increased during osteogenic differentiation while miR-122 exhibited a decreased expression. Moreover, overexpression of circ_0011269 could promote RUNX2 expression and inhibit osteoporosis. In summary, this study found that circ_0011269 sponges miR-122 to regulate RUNX2 expression and promotes osteoporosis progression.

The PI3K/AKT pathway promotes fracture healing through its crosstalk with Wnt/ß-catenin.

PI3K/AKT is one of the key pathways that regulate cell behaviors including apoptosis, proliferation, and differentiation. Although previous studies have demonstrated that this pathway is a crucial regulator of osteoblasts, the role of PI3K/AKT in fracture healing remains unclear. It is well known that the Wnt/ß-catenin pathway plays an essential role in bone regeneration. However, whether there exists crosstalk between Wnt/ß-catenin and PI3K/AKT in regulating osteoblasts and bone repair has not been reported. To address these issues, we establish a stabilized fracture model in mice and show that PI3K inhibitor LY294002 substantially inhibits the bone healing process, suggesting that PI3K/AKT promotes fracture repair. More importantly, we report that PI3K/AKT increases phosphorylation of GSK-3ß at Ser9 and phosphorylation of ß-catenin at Ser552 in fracture callus and murine osteoblastic MC3T3-E1 cells, both of which lead to ß-catenin stabilization, nuclear translocation, as well as ß-catenin-mediated TCF-dependent transcription, suggesting that ß-catenin is activated downstream of PI3K/AKT. Furthermore, we show that ICG001, the inhibitor of ß-catenin transcriptional activity, attenuates PI3K/AKT-induced osteoblast proliferation, differentiation, and mineralization, indicating that the PI3K/AKT/ß-catenin axis is functional in regulating osteoblasts. Notably, the PI3K/AKT pathway is also activated by Wnt3a and is involved in Wnt3a-induced osteoblast proliferation and differentiation. Hence, our results reveal the existence of a Wnt/PI3K/AKT/ß-catenin signaling nexus in osteoblasts, highlighting complex crosstalk between PI3K/AKT and Wnt/ß-catenin pathways that are critically implicated in fracture healing.

BMP2 Modified by the m6A Demethylation Enzyme ALKBH5 in the Ossification of the Ligamentum Flavum Through the AKT Signaling Pathway.

Ossification of the ligamentum flavum (OLF) is characterized by a process of ectopic bone formation in the ligamentum flavum. The definitive pathophysiology of OLF still remains unclear, but the epigenetic m6A modification plays an important role in OLF. In addition, no studies have reported the function of ALKBH5 in OLF development. In this study, we investigated the function of the m6A demethylation enzyme ALKBH5 in OLF. To evaluate the function of ALKBH5, OLF tissues and normal ligamentum flavum tissues were collected. In vitro methods, including HE, IHC and western blotting assays, were used to evaluate the association of ALKBH5 with OLF. In addition, we verified the effects of ALKBH5 on osteogenesis using alizarin red and ALP staining. MeRIP q-PCR was performed to investigate the methylation level of BMP2. Moreover, the mechanism of ALKBH5-mediated regulation of the ossification of the ligamentum flavum cells through the AKT signaling pathway was also verified. The present study showed that the expression of ALKBH5 increased in OLF tissues. The overexpression of ALKBH5 increased the expression of osteogenic genes and promoted the ossification of ligamentum flavum cells. Furthermore, BMP2 was significantly enriched in the ligamentum flavum cells of the anti-m6A group compared with those of the IgG group. The overexpression of ALKBH5 led to the activation of p-AKT, and BMP2 was regulated by ALKBH5 through the AKT signaling pathway. ALKBH5 promoted the osteogenesis of the ligamentum flavum cells through BMP2 demethylation and AKT activation. ALKBH5 was shown to be an important demethylation enzyme in OLF development.

Synergism of amlodipine and candesartan on blood pressure reduction and organ protection in hypertensive rats.

This study was designed to investigate the possible synergism of amlodipine and candesartan on the reduction of blood pressure (BP) in hypertensive rats. The end organ protection was also observed. In acute experiment, spontaneously hypertensive rats (SHRs) were treated with intragastric administration of amlodipine (0.5, 1, 2, 3 mg/kg), candesartan (1, 2, 3, 4, 6, 8 mg/kg), and 14 different combinations to find the possible ratio of synergistic interaction. In two kidneys, one clip (2K1C) rats, the effects of amlodipine (1 mg/kg), canderastan (2 mg/kg) and their combination on BP reduction were also observed. In chronic study, SHRs were treated with amlodipine (1 mg/kg), candesartan (2 mg/kg), and their combination for 5 months. Organ damage evaluation was performed after BP recording. The probability sum test (q test) was used to evaluate the synergistic action. There is a synergistic interaction between amlodipine and candesartan on BP reduction. The optimal dose ratio is 1:2. The synergistic effect was also confirmed by 2K1C hypertensive rats. In chronic study, this combination (1:2) possessed an obvious synergism on the reduction of BP and BP variability (BPV) and protection on end organs. Multiple regression analysis showed that heart and aortic hypertrophy indexes and glomerular damage parameters were positively related to BP and BPV. In conclusion, combination of amlodipine and candesartan exhibited a potent antihypertensive effect and possessed an obvious synergism on BP reduction and organ protection in hypertension. The optimal proportion was 1:2. BP and BPV reduction may both importantly contribute to end organ protection.

Evaluation of Degenerative Lumbar Scoliosis After Short Segment Decompression and Fusion.

The objective of this study was to investigate short segment decompression of degenerative lumbar scoliosis (DLS) and the efficiency of fusion treatment.After DLS surgery, the patients were retrospectively reviewed using the VAS (visual analog scale) and ODI (Oswestry Disability Index) to assess clinical outcomes. All patients underwent posterior lumbar decompressive laminectomy, pedicle screw internal fixation, and posterolateral bone graft fusion surgery. Radiographic measurements included the scoliotic Cobb angle, the fused Cobb angle, the anterior intervertebral angle (AIA), the sagittal intervertebral angle (SIA), and lumbar lordosis angle. The relationships between these parameters were examined by bivariate Pearson analysis and linear regression analysis.Preoperatively, the Cobb angle at the scoliotic segment was 15.4°, which decreased to 10.2° immediately following surgery (P < 0.05). The AIA significantly increased by the last follow-up (4.4 ± 3.4) compared with pre- and postoperative values (2.5 ± 2.8 and 2.2 ± 2.4, respectively; P < 0.05). However, the scoliotic Cobb angle and the AIA did not correlate with the VAS or ODI scores. At the final follow-up, no patients had pseudoarthrosis or internal instrumentation-related complications.Short fusion surgical treatment results in limited DLS correction, with correction loss over time. The AIA between the upper adjacent segment and proximal fused vertebra continues to increase postoperatively, which does not exacerbate clinical symptoms, as reflected by the low reoperation rates for repairing degeneration at adjacent levels.

Down-regulation of microRNA152 is associated with the diagnosis and prognosis of patients with osteosarcoma.

Potential values of microRNA152 (miR-152) as a serum diagnostic and prognostic biomarker have not been determined in human osteosarcoma. By detecting the expression of miR-152 among 80 osteosarcoma patients, 20 periostitis patients and 20 healthy individuals using qRT-PCR, we aimed to explore the clinical significance of miR-152 in osteosarcoma patients. The expression of miR-152 was significantly decreased in patients with osteosarcoma compared to patients with periostitis (P<0.01) and healthy controls (P<0.01). The relationship between clinicopathologic characteristics and miR-152 was analyzed by chi-square test. The outcome indicated that miR-152 might be linked with the development of osteosarcoma. Moreover, the receiver operating characteristic (ROC) curve was performed to estimate the diagnostic value of miR-152. The result demonstrated that miR-152 might be a promising diagnostic marker of osteosarcoma with an AUC of 0.956, combing with 92.5% specificity and 96.2% sensitivity. The relationship between miR-152 and overall survival of osteosarcoma patients was analyzed by Kaplan-Meier curve and log rank test. As a result, the survival time of patients with low miR-152 expression was significantly shorter than those with high miR-152 expression (P<0.001). Then Cox regression analysis was used to estimate the prognostic value of miR-152 in osteosarcoma. The outcomes showed that low miR-152 expression (P=0.004) might be a potential independent prognostic marker for osteosarcoma patients. These findings suggested that down-regulation of miR-152 could be considered as a predictor for diagnosis and prognosis of osteosarcoma patients.

Comparison of rhBMP-2 versus Autogenous Iliac Crest Bone Graft for 2-Level Anterior Cervical Discectomy and Fusion for Cervical Spondylotic Myelopathy.

BACKGROUND: Few studies have examined the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) in 2-level anterior cervical discectomy and fusion (ACDF). The purpose of this study was to compare the outcomes in a series of patients with CSM treated with 2-level ACDF with or without rhBMP-2. MATERIAL AND METHODS: The retrospective study included a total of 146 patients with CSM. The rhBMP-2 group consisted of 73 patients who underwent 2-level ACDF with rhBMP-2. A total of 73 patients who also received 2-level ACDF with autogenous ICBG alone were included in the matched-pair ICBG group with a ratio of 1:1, based on age, sex, and BMI. All data, including fusion rate and time, VAS, JOA score, operative date, and complications, were assessed. RESULTS: With respect to the length of hospital stay, operative times, and blood loss, there were no significant difference between the 2 groups. However, the rhBMP-2 group presented a shorter fusion time (P<0.013) and higher fusion rate (P<0.036) than the ICBG group. In the rhBMP-2 group, 22% required additional treatment for complications compared to 18% of patients in the ICBG group, which showed no significant difference (P=0.543). CONCLUSIONS: The application of rhBMP-2 in 2-level ACDF showed higher fusion rates, shorter fusion time, and similar function outcomes compared to those who received ACDF with ICBG alone.

Comparative Study of Modified Posterior Operation to Treat Kümmell's Disease.

The present study aimed at examining the curative effect of modified posterior operation on treatment of Kümmell's disease. About 30 patients of Kümmell's disease with complete image and clinical data treated during June 2004 to July 2013 were conducted with anterior and posterior approaches, respectively. Kyphotic Cobb angle, fractured vertebra wedge angle, and the anterior and posterior heights of fractured vertebra were all measured through x-ray before and after operation, and the pain visual analog scale (VAS) was determined for evaluating the effect of operations. The injury and restoration of neurological function were assessed using Frankel classification. Patients in group A were treated with anterior operation, whereas group B was posterior operation. Postoperatively, VAS score, kyphotic Cobb angle, anterior vertebra height, and pathologic vertebra wedge angle were all significantly improved in patients with Kümmell's disease receiving modified posterior operation (group B). Similar results were also observed in patients with anterior operation. The improvement of VAS and correction rate of kyphotic Cobb angle indicated equivalent effects of posterior and anterior operations. Meanwhile, alleviated neurological function damage was observed in 2 groups. Relevant factor analysis illustrated that there was no significant correlation of the severity and improvement rate of pain symptoms with age, medical history, anterior and posterior vertebra heights, kyphotic Cobb angle, and pathological vertebra wedge angle. Compared with traditional anterior approach, modified posterior operation, adopting transpedicular vertebral body grafting combined with vertebral pedicle screw fixation, could produce equivalent effects on kyphosis correction, pain relief, and improvement of neurological function in patients with Kümmell's disease.

Association between CTLA-4 gene polymorphism and ankylosing spondylitis: a case-control study.

AIMS: The aim of our study was to evaluate the association between CTLA-4 polymorphisms (+49A/G, -318C/T and CT60A/G) and ankylosing spondylitis (AS) susceptibility. METHODS: A total of 120 AS cases and healthy controls, matched on the age and gender, were enrolled in the study. Polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) were used to determine the gentypes of +49A/G, -318C/T and CT60A/G polymorphisms. Genotype distribution in control group was assessed by Hardy Weinberg Equilibrium (HWE) test. Odds ratio (OR) with 95% confidence interval (95% CI) were adopted to evaluate the relationship of CTLA-4 polymorphisms and AS susceptibility. RESULTS: In our study, genotype distribution of the three polymorphisms in control group was consistent with the HWE (P > 0.05). The genotype analysis showed that AA genotype of + 49A/G polymorphism could increase the risk for AS (OR=2.357, 95% CI=1.127-4.930). Moreover, the frequency of A allele was also presented as a risk factor for AS. Additionally, AA genotype and A allele of CT60A/G appeared to be related with AS susceptibility (OR=2.610, 95% CI=1.047-6.510; OR=1.751, 95% CI=1.160-2.641). However, the T allele of -318C/T appeared to be a protective factor for AS (OR=0.383, 95% CI=0.228-0.643). CONCLUSION: In summary, there existed significant association between CTLA-4 gene polymorphisms and increased or decreased risk for AS.

TNF-α and IL10 polymorphisms interaction increases the risk of ankylosing spondylitis in Chinese Han population.

AIMS: The target of this article was to reveal the role of tumor necrosis factors α (TNF-α) and Interleukin-10 (IL10) gene polymorphisms in ankylosing spondylitis (AS) development and explore the interaction between these two gene polymorphisms. METHODS: The genotyping of gene polymorphims was conducted using ABI Taqman assay method in 84 AS patients and 92 healthy people. Hardy-Weinberg equilibrium (HWE) was checked in the control group and the genotypes and alleles difference were compared with χ(2) test. Odds ratio (OR) with 95% confidence interval (CI) was calculated to identify the strength of association between gene polymorphism and disease. Meanwhile, multifactor dimensionality reduction (MDR) method was used to analysis the interaction between gene polymorphisms. RESULTS: The genotypes CG+CC of the minor allele in IL10 rs1878672 in cases was obviously higher frequency than the controls (P=0.03) and the minor allele C was also associated with the increased risk of AS, compared with G allele (OR=2.05, 95% CI=1.08-3.89). Rs3024490 in IL10 also showed a significant correlation to the onset risk of AS (GG vs. TT: OR=3.03, 95% CI=1.04-8.87; G vs. T: OR=1.70, 95% CI=1.08-2.68). What's more, there was the interaction between TNF-α rs3093662 and IL10 rs3021094, rs3024490 polymorphisms in AS. CONCLUSIONS: IL10 rs1878672 and rs3024490 polymorphisms obviously increase the susceptibility to AS, but not TNF-α rs3093662. Both IL10 and TNF-α polymorphisms may affect the onset of AS.

Genetic analysis of TNFST15 variants in ankylosing spondylitis.

AIMS: The purpose of this study was to explore the role of TNF-like ligand 1A (TL1A) gene (TNFST15) polymorphisms (rs3810936, rs7848647, and rs6478109) in the generation of ankylosing spondylitis (AS). METHODS: Polymerase chain reaction (PCR) and sequencing were used to conduct the genotyping of TNFSF15 polymorphisms in 113 AS patients and 120 healthy persons as the case and control groups. The frequencies comparison was performed by chi-square or t test between the two groups. Odds ratio (OR) and 95% confidence interval (95% CI) were calculated to represent the correlation between TNFSF15 polymorphism and AS. Besides, genotypes distribution of the former in controls was checked by Hardy-Weinberg equilibrium (HWE). RESULTS: There was statistically significant difference in AS patients and controls based on family history. Among TNFSF15 polymorphisms, only TT genotype frequency of rs3810936 in cases was obviously high, compared with the controls (P=0.04), the results indicated that TT was a high-risk genotype (OR=2.31, 95% CI=1.03-5.20). However, both of rs6478109, rs7848647 polymorphisms didn't show any association with AS. CONCLUSION: Rs3810936 of TNFSF15 were related to the risk of AS and we should pay more attention to the role of TNFSF15 polymorphisms in the pathogenesis of AS in the future.

CT findings of primary clear cell carcinoma of liver: with analysis of 19 cases and review of the literature.

PURPOSE: To analyze CT characteristics of primary clear cell carcinoma of the liver (PCCCL) and improve the current understanding and diagnose accuracy of the tumor. METHODS: Pre- and post-contrast CT images of 19 patients with pathology proven PCCCL were retrospectively analyzed. The clinical data and CT findings as well as relevant literature reports were reviewed. RESULTS: Thirteen patients were tested positive for HBsAg, and two patients were positive for HCVAb. The serum alpha-fetoprotein (AFP) levels of most tumors (14/19) were ≤20 ng/ml with 14 cases were associated with liver cirrhosis. All lesions were solitary intraparenchymal mass lesions which have well-defined boarders. On pre-contrast CT scans, 15 lesions appeared as hypo-attenuation and four lesions appeared as isointensity to the adjacent liver parenchyma. On post-contrast CT scans, 16 lesions showed avid enhancement on the hepatic arterial phase, of which 6 lesions were hypo-attenuation, and 10 lesions remained slightly hyper-attenuation or iso-attenuation on the portal venous phase images. Three lesions showed only mild enhancement on the hepatic arterial phase and hypo-attenuation on the portal venous phase. All lesions demonstrated hypointensity on the equilibrium phase. There are 12 lesions showed pseudocapsules. None of patients showed signs of portal vein thrombosis. There was no distal metastasis except only one patient had lymph node metastasis. CONCLUSION: The characteristics of CT imaging of PCCCL, such as tend to form pseudocapsules and less involved with vascular invasion, could be useful in differentiating from common type hepatocellular carcinoma (CHCC). Some CT imaging characteristics of PCCCL are similar to CHCC, such as prone to occur in patients with liver cirrhosis and early enhancement pattern on the hepatic arterial phase as well as hypo-attenuation on the equilibrium phase. Those features could be useful in differentiating PCCCL from other liver tumors, such as hemangioma and hepatic metastases.

Raw-data-based iterative reconstruction versus filtered back projection: image quality of low-dose chest computed tomography examinations in 87 patients.

OBJECTIVE: The objective was to compare standard-dose chest computed tomography (CT) reconstructed with filtered back projection (FBP) versus low-dose images with FBP and raw-data-based iterative reconstruction. METHODS: Eighty-seven consecutive patients (46 male; mean age, 54.54 ± 16.12; mean body mass index, 24.58 ± 4.07) referred for initial chest CT with full-dose examinations [mean dose-length product (DLP), 183.37 ± 44.13 mGy · cm] and follow-up chest CT with half-dose examinations (mean DLP, 91.08 ± 23.81 mGy · cm) were included. The full-dose protocol was reconstructed with FBP; the half-dose protocol was reconstructed with FBP and sinogram-affirmed iterative reconstruction (SAFIRE). Noise and signal-to-noise ratio were compared using a paired Student's t test; subjective image quality and lesion conspicuity were compared using Wilcoxon signed ranks test. RESULTS: Actual radiation dose of follow-up CT was about 50% (49.26% ± 2.62%) of standard-dose protocol. Compared to full-dose images with FBP, there was no significant difference in half-dose images with SAFIRE in the objective noise (ascending aorta: P=.38, descending aorta: P=.70, trachea on mediastinal images: P=.37) and SNR (ascending aorta: P=.14, descending aorta: P=.72, trachea on mediastinal images: P=.06) on mediastinal images. Noise was significantly lower (P<.001) and SNR was significantly higher (P<.001) in half-dose images with SAFIRE on lung images. Noise was significantly higher (P<.001) and SNR was significantly lower (P<.001) in half-dose images with FBP. Subjective image quality was similar on both mediastinal images (P=.317) and lung images (P=.614) of half-dose SAFIRE images versus full-dose FBP images. Lesion conspicuity was also similar. Subjective image quality was significantly lower on both mediastinal images (P<.001) and lung images (P<.001) of half-dose FBP images versus full-dose FBP images. The conspicuity of some lesions was significantly lower (ground-glass opacity, P<.0001; ill-defined micronodule, P<.0001; lung cyst, P<.0001; emphysematous lesion, P=.003) on half-dose FBP versus full-dose FBP images. CONCLUSION: Compared to full-dose CT images reconstructed with the conventional FBP algorithm, SAFIRE with three iterations could provide similar or better image quality at 50% less dose.

Icariin protects against glucocorticoid-induced osteoporosis in vitro and prevents glucocorticoid-induced osteocyte apoptosis in vivo.

Icariin is the major active ingredient in Herba epimedii which is a commonly used Chinese herbal medicine for the treatment of osteoporosis. The present study aims to evaluate the osteoprotective effect of Icariin in glucocorticoid-induced osteoporosis in vivo and investigate the effect of Icariin on glucocorticoid-induced osteocyte apoptosis in vitro. A total of 48 female Sprague-Dawley rats were used. Glucocorticoid-induced osteoporosis was induced by daily injections of dexamethasone (0.1 mg/kg, daily, s.c.) for 60 days, whereas sham animals were injected daily with vehicle. At the end of the osteoporosis development period, osteoporotic rats were randomized to receive: vehicle (n = 8), Icariin (5,125 mg/kg, i.g.; n = 8), or alendronate (0.03 mg/kg, s.c.; n = 8) for 12 weeks. Sham animals were treated with vehicle for 12 weeks. At the beginning and at the end of treatments, animals were examined for bone mineral density. Serum bone-alkaline phosphatase and carboxy-terminal collagen cross links were measured. Primary osteocytes were isolated, and apoptosis was determined by trypan-blue assay. Interaction between Icariin and estrogen receptor and prosurvival signaling pathways activated by Icariin were also investigated. Icariin showed a comparable efficacy with alendronate in increasing bone mass. Icariin significantly increased bone-alkaline phosphatase (bone formation marker) and reduced carboxy-terminal collagen cross links (bone resorption marker). In vitro studies demonstrated that Icariin significantly prevented GC-induced apoptosis in osteocytes by activating ERK signaling via estrogen receptor. Our results suggest that Icariin might exert osteoprotective effect by maintaining osteocyte viability, thereby, regulating bone remodeling. Furthermore, our study provides preclinical evidence for the efficacy of Icariin for management of Glucocorticoid-induced osteoporosis.