The consumption of a high-fat diet(HFD)has been linked to osteoporosis and an increased risk of fragility fractures.However,the specific mechanisms of HFD-induced osteoporosis are not fully understood.Our study shows that exposure to an HFD induces premature senescence in bone marrow mesenchymal stem cells(BMSCs),diminishing their proliferation and osteogenic capability,and thereby contributes to osteoporosis.Transcriptomic and chromatin accessibility analyses revealed the decreased chromatin accessibility of vitamin D receptor(VDR)-binding sequences and decreased VDR signaling in BMSCs from HFD-fed mice,suggesting that VDR is a key regulator of BMSC senescence.Notably,the administration of a VDR activator to HFD-fed mice rescued BMSC senescence and significantly improved osteogenesis,bone mass,and other bone parameters.Mechanistically,VDR activation reduced BMSC senescence by decreasing intracellular reactive oxygen species(ROS)levels and preserving mitochondrial function.Our findings not only elucidate the mechanisms by which an HFD induces BMSC senescence and associated osteoporosis but also offer new insights into treating HFD-induced osteoporosis by targeting the VDR-superoxide dismutase 2(SOD2)-ROS axis.

The consumption of a high-fat diet(HFD)has been linked to osteoporosis and an increased risk of fragility fractures.However,the specific mechanisms of HFD-induced osteoporosis are not fully understood.Our study shows that exposure to an HFD induces premature senescence in bone marrow mesenchymal stem cells(BMSCs),diminishing their proliferation and osteogenic capability,and thereby contributes to osteoporosis.Transcriptomic and chromatin accessibility analyses revealed the decreased chromatin accessibility of vitamin D receptor(VDR)-binding sequences and decreased VDR signaling in BMSCs from HFD-fed mice,suggesting that VDR is a key regulator of BMSC senescence.Notably,the administration of a VDR activator to HFD-fed mice rescued BMSC senescence and significantly improved osteogenesis,bone mass,and other bone parameters.Mechanistically,VDR activation reduced BMSC senescence by decreasing intracellular reactive oxygen species(ROS)levels and preserving mitochondrial function.Our findings not only elucidate the mechanisms by which an HFD induces BMSC senescence and associated osteoporosis but also offer new insights into treating HFD-induced osteoporosis by targeting the VDR-superoxide dismutase 2(SOD2)-ROS axis.

Objective To analyze the global status of COVID-19 epidemics, so as to preliminarily forecast the epidemic trend. Methods The epidemiological data of 208 countries and the prevention and control policies implemented by typical countries from December 31, 2019 to December 14, 2020 were collected. We use the cumulative incidence rate, cumulative mortality, cumulative fatality and real-time dependent reproduction number (R_t) to analyze the epidemic status. We use the provenance package to group different countries and discuss the effect of prevention and control measures. Results As of December 14, 2020, a cumulative incidence of 93.49 per 10000, a cumulative mortality rate of 0.21‰, and a cumulative fatality rate of 3.1‰ had been reported globally.112 of the 208 countries still had R_t ≥ 1.0, and 96 countries had R_t <1.0. The grouping of 208 countries showed that countries from the same continent often gather together and were geographically adjacent. Countries that were geographically adjacent could easily be grouped together. Conclusion As of December 14, 2020, the epidemic situation in most countries had not been effectively controlled, and epidemic prevention and control are facing greater pressure. Sub-Saharan countries currently had a high R_t , and the government had adopted more relaxed epidemic prevention measures. The epidemic situation in this region may continue to deteriorate, and needs to be focused in the later period.

Objective:To explore the characters of CDU imaging anatomy and results of clinical application of perforating branch of median cubital vein, and to find the evidence of utilizing perforating vein to establish high level hemodialysis access.Methods:From November, 2016 to October, 2019, 150 median cubital veins in 75 persons were observed by CDU. And the inner diameter and length of the perforating branch were measured Perforating branches of median cubital vein were categorized with ultrasonic imaging anatomy. Thirty-eight chronic kidney failure patients who can not build forearm fistulas were operated by end-to-side anastomosis between perforating branch vein and brachial artery to build hemodialysis access. The blood flow of fisultas was measured,the mature period of fisultas was recorded. The length of available vessels of fisultas was measured and the long-term utilization rate of fisultas was counted.Results:Perforating branch of median cubital vein was always located in a little below elbow near brachial artery, the rate of occurrence was 94.0%. It was sent out at intersection of veins. There were 4 types of perforating vein in image-anatomy. There was no significant difference in vessel length and vessel inner diameter between different types ( P>0.05) ; All the 38 patients with mature fistulas could meet the needs of hemodialysis. The available vascular length of fistulas in type I and type II patients was better than that in type III ( P<0.01), and the long-term utilization rates of fistulas in type I, type II and type III were 84.6%, 85.7% and 72.7%, respectively. There was no significant difference in blood flow and mature period between different types ( P>0.05) . Conclusion:It is most safe and reliable to use the type I and type II of perforating branch of median cubital vein to make the high level fistulas , which can provide a safe and efficient hemodialysis access for the patients with forearm vascular drain, elderly diabetes patients and difficult fistulas with repeatedly thrombosis.

Objective: To investigate the long-term outcomes of posterior long segment instrumentation and fusion in adult degenerative scoliosis (ADS), and to explore the correlative factors of sagittal imbalance after long segment instrumentation and fusion, and to summarize the impacts of different lowest instrumented vertebra (LIV) on sagittal complication rates. Methods: ADS patients who underwent long segment instrumentation and fusion between January 2008 and January 2014 were retrospectively reviewed and divided into two groups depended on LIV (L ₅ group and S₁ group). The follow-up time was at least five years. Radiographic parameters, Visual Analogue Score (VAS), Oswestry Disability Indexscore(ODI), the 12-item Short Form Health Survey-Physical Component Summary (SF-12 PCS)and sagittal complications were analyzed. And the correlation between sagittal imbalance and sagittal complications were calculated. Patients were divided into two groups(sagittal imbalance group and sagittal balance group) to explore the correlative factors of sagittal imbalance. Results: All of 56 patients were included and evaluated in this study, and 35 cases stopped at L ₅, 21 cases at S₁. The mean follow-up time was 6.6±1.6 years. No significant difference were found in age, gender, follow-up time and surgery method (P>0.05) between two groups. No significant differences were found in Cobb angle(11.8°±7.3° vs 12.6°±6.4°), coronal balance distance(CBD) (0.7±0.6 cm vs 1.0±0.5 cm), sagittal vertebral axis(SVA)(3.0±3.1 cm vs 2.6±5.6 cm), thoracic kyphosis(TK) (21.4°±9.6° vs 22.5°±6.9°), lumbar lordosis(LL) (-32.7°±7.3° vs-34.8°±9.1°), pelvic tilt (PT) (23.4°±9.8° vs 23.3°±8.1°), VAS score(2.0±1.2 vs. 2.2±0.9), ODI score(18.5%±6.4% vs 19.3%±5.2%) and SF-12 PCSscore(45.5±5.2 vs 42.4±7.0) between two groups at final follow-up time(P>0.05). Radiographic parameters including Cobb angle, CBD, SVA and health related quality of life scores including VAS score, ODI score and SF-12 PCS scores were improved significantly at two weeks postoperatively, two-year follow-up time andfinal follow-up time in two groupscompared with those preoperatively (P<0.05). And no significant difference were found in radiographic parameters and health related quality of life scores between those at two years follow-up time and those at final follow-up time; Sagittal complication rates at final follow-up were higher than these at two years follow-up (82.1% vs 33.9%, P=0.000). Sagittal imbalance was related to internal fixation failure in L ₅ group (r=0.691, P=0.011), internal fixation failure in S₁ group (r=0.691, P=0.001) and pseudoarticulation formation (r=0.499, P=0.021). 10 patients in the sagittal imbalance group were with preoperative sagittal imbalance, 9 with preoperative coronal imbalance, 6 with internal fixation failure, 5 with proximal junctional kyphosis (PJK), 4 with adjacent segment degeneration during the follow-up periods, the incidence rates of which were higher than those in the sagittal balance group. LL in the sagittal imbalance group was lower than that in the sagittal balance group at two years follow-up time and final follow-up time. Compared with the sagittal imbalance group, the sagittal balance group achieved a higher SF-12 PCS (45.4±5.1 vs 41.6±7.4, P<0.05) and lower ODI scores (17.8%±6.1% vs 21.5±4.6%, P<0.05), and no significant difference was found in VAS scores between two groups (1.9±1.2 vs 2.4±0.8, P>0.05). The incidence of adjacent segment degeneration in L ₅ group was higher than that in S₁ group (P<0.05) at final follow-up time, and the incidence of pseudojoint in S₁ group was higher than that in L ₅ group (P=0.002) at final follow-up time. Conclusion Posterior long segment instrumentation and fusion for adult degenerative spinal deformity can obtain satisfying long-term clinical outcomes, and postoperative sagittal imbalance was related to preoperative sagittal/coronal imbalance, postoperativeinternal fixation failure, PJK, pseudoarticulation formation and adjacent segment degeneration. Distal fusion at L ₅ or S₁ may lead to high risk of adjacent segment degeneration or pseudoarticulation formation respectively.

OBJECTIVE: To systematically evaluate the application of microcapsuled cell or encystation materials for treating diabetes mellitus at hone or abroad in recent years.METHODS: A computer-based online search of PubMed database was undertaken to identify related articles about the microcapsulated cell or encystation material for treating diabetes mellitus published from 1980 to 2009 by using the key words of "microcapsulation, islet, transplantation" in English. Meanwhile, we search CNKI for relevant articles published between 1999 and 2009 with the same key words in Chinese. The related randomized, controlled, and clinical studies were collected according to conclusion and exclusion criteria.RESULTS: Among 25 articles, there were 46 patients with type I diabetes mellitus, 106 rats, 20 pigs, and 25 monkeys. The experimental results showed that both the microcapsulated islets and non-microcapsulated islets could secrete insulin and decrease blood glucose level. The normal blood glucose level with microcapulated islets could be maintained for a long time.Thus, microcapsule had a great immune isolation reaction.CONCLUSION: After transplantation, microencapsulated islet cells could improve and adjust abnormal glycometabolism of patients with diabetes mellitus; furthermore, the immunoisolation effect of microcapsule could eliminate or relieve the immunological rejection of receptors to allograft or xenograft, while it could also relieve or eliminate dependence on immunosuppressive drugs. Appropriate material of microcapsule, reasonable process, advanced equipment, advanced separation and purification technologies of islet, and suitable site for transplantation could improve the function of artificial islet cell, enhance the anti-machinery and chemical strength of microencapsuiated islet, improve biocompatibility, and prolong survival time.