The role of pleiotrophin in bone repair

Bone has an enormous capacity for growth, regeneration, and remodelling, largely due to induction of osteoblasts that are recruited to the site of bone formation. Although the pathways involved have not been fully elucidated, it is well accepted that the immediate environment of the cells is likely to play a role via cell–matrix interactions, mediated by several growth factors. Formation of new blood vessels is also significant and interdependent to bone formation, suggesting that enhancement of angiogenesis could be beneficial during the process of bone repair. Pleiotrophin (PTN), also called osteoblast-specific factor 1, is a heparin-binding angiogenic growth factor, with a well-defined and significant role in both physiological and pathological angiogenesis. In this review we summarise the existing evidence on the role of PTN in bone repair.     

Ulnar styloid process nonunion and outcome in patients with a distal radius fracture: A meta-analysis of comparative clinical trials

PurposeThere is no consensus on the relation between ulnar styloid process nonunion and outcome in patients with distal radius fractures. The aim of this study was to analyze whether patient-reported outcome is influenced by the nonunion of the accompanying ulnar styloid fracture in distal radius fracture patients.MethodsA meta-analysis of published studies comparing outcomes after distal radius fractures with a united versus a non-united ulnar styloid process was performed. In addition, if provided by the authors, the raw data of these studies were pooled and analysed as one study. The outcome measures of the analyses included patient-reported outcome, functional outcome, grip-strength, pain, and distal radioulnar joint (DRUJ) instability.ResultsData from six comparative studies were included, concerning 365 patients with a distal radius fracture. One hundred and thirty-five patients with an ulnar styloid union were compared with 230 patients with a nonunion of the ulnar styloid. No significant differences were found between groups regarding any outcome measure.ConclusionBased on this meta-analysis, there is no relation between the nonunion of the ulnar styloid process and function in patients with a distal radius fracture.     

Plate selection for fixation of extra-articular distal humerus fractures: A biomechanical comparison of three different implants

Operative fixation of extra-articular distal humerus using a single posterolateral column plate has been described but the biomechanical properties or limits of this technique is undefined. The purpose of this study was to evaluate the mechanical properties of distal humerus fracture fixation using three standard fixation constructs.Two equal groups were created from forty sawbones humeri. Osteotomies were created at 80 mm or 50 mm from the tip of the trochlea. In the proximal osteotomy group, sawbones were fixed with an 8-hole 3.5 mm LCP or with a 6-hole posterolateral plate. In the distal group, sawbones were fixed with 9-hole medial and lateral 3.5 mm distal humerus plates and ten sawbones were fixed with a 6-hole posterolateral plate. Biomechanical testing was performed using a servohydraulic testing machine. Testing in extension as well as internal and external rotation was performed. Destructive testing was also performed with failure being defined as hardware pullout, sawbone failure or cortical contact at the osteotomy.In the proximal osteotomy group, the average bending stiffness and torsional stiffness was significantly greater with the posterolateral plate than with the 3.5 mm LCP. In the distal osteotomy group, the average bending stiffness and torsional stiffness was significantly greater with the posterolateral plate than the 3.5 mm LCP. In extension testing, the yield strength was significantly greater with the posterolateral plate in the proximal osteotomy specimens, and the dual plating construct in the distal osteotomy specimens. The yield strength of specimens in axial torsion was significantly greater with the posterolateral plate in the proximal osteotomy specimens, and the dual plating construct in the distal osteotomy specimens.Limited biomechanical data to support the use of a pre-contoured posterolateral distal humerus LCP for fixation of extra-articular distal humerus exists. We have found that this implant provided significantly greater bending stiffness, torsional stiffness, and yield strength than a single 3.5 mm LCP plate for osteotomies created 80 mm from the trochlea. At the more distal osteotomy, dual plating was biomechanically superior. Our results suggest that single posterolateral column fixation of extra-articular humerus fractures is appropriate for more proximal fractures but that dual plate fixation is superior for more distal fractures.     

Factors associated with outcome of spinopelvic dissociation treated with lumbopelvic fixation

Spinopelvic dissociation is a rare high-energy injury, which is frequently associated with lumbosacral plexus and cauda equina deficits. During an 18-year period, 36 consecutive patients with a H-type sacral fracture and spinopelvic dissociation were treated using lumbopelvic fixation with a minimum follow-up of 18 months. We evaluated factors prognostic of outcome after standardised surgical fixation and neural decompression. Neurological recovery was assessed by Gibbons’ criteria. Pelvis Outcome Scale (POS clinical score) was used to evaluate the clinical outcome. Despite excellent or good radiological results in the vertical components of the sacral fractures having been achieved in all patients, 15 patients (42%) had a poor clinical outcome. The degree of initial translational displacement in the transverse sacral fracture was significantly associated with neurological recovery (as defined by a change in Gibbons score) (p = 0.038) and final POS clinical score (p < 0.001). Both neurological recovery and clinical outcome were worse in patients with completely displaced fractures than in patients with a partially displaced sacral fracture. The degree of residual translational displacement and kyphosis in the transverse sacral fracture were also associated with clinical outcome (POS clinical score) (p = 0.011 and p = 0,018, respectively). However, Roy-Camille classification (type 2 vs. type 3), age, gender, ISS, timing of surgery, and sacral laminectomy did not have a statistically significant association with the outcome. Based on the results, Roy-Camille sacral fracture classification (type 2 vs. type 3) was not prognostic of neurological impairment. Thus further categorisation of the transverse sacral fractures as partially displaced or completely displaced could be used to predict the rate of neurological recovery following lumbopelvic fixation. Accurate reduction of all sacral fracture components seems to be associated with better clinical outcome.     

Resveratrol plays dual roles in pancreatic cancer cells

Purpose

Although the potential anticancer effect of resveratrol (RSV) on pancreatic cancer has been reported, its mechanism was not fully understood. The role of vascular endothelial growth factor B (VEGF-B) in cancer remains controversial. Herein, we aimed to examine whether the anticancer effect of RSV was related to the VEGF-B.

Methods

The effect of RSV on pancreatic cancer cell line (capan-2 cells) was evaluated by CCK-8 assay, Hoechst 33342 staining, and flow cytometry. The mRNA level of VEGF-B was measured by real-time PCR. VEGF-B expression was knockdown by small interfering RNA (siRNA).The protein levels of VEGF-B, glycogen synthase kinase-3 beta (GSK-3β), and Bax were measured by Western blot.

Results

Resveratrol treatment inhibited tumor growth, induced apoptosis, and up-regulated Bax expression in capan-2 cells. The mRNA and protein levels of VEGF-B were up-regulated after RSV treatment. However, VEGF-B siRNA treatment increased the apoptotic rate, and inhibited tumor activator GSK-3β, while Bax expression was not affected. The combination of RSV and VEGF-B siRNA showed significantly higher apoptotic rate in comparison with RSV or VEGF-B siRNA mono-treatment group.

Conclusions

Resveratrol plays dual roles in pancreatic cancer: as a tumor suppressor via the up-regulation of Bax; as a tumor activator via the up-regulation of VEGF-B; and the anticancer effect of RSV is much stronger than the cancer promotion effect. The combination of RSV with pharmacological inhibitor of VEGF-B might, therefore, be a promising modality for clinical pancreatic cancer therapy.     

软骨组织工程用羧甲基壳聚糖/氧化海藻酸钠 复合水凝胶的制备及体外评估

目的 优化羧甲基壳聚糖/氧化海藻酸钠（CMCS/OSA）复合水凝胶制备工艺,并应用于软骨组织工程。方法 制备氨基与醛基比例分别为2:1、1:1、1:2的CMCS/OSA复合水凝胶,并通过扫描电子显微镜观察、流变学检测、黏附拉力测试、溶胀率分析及细胞实验等方法评价复合水凝胶的微观形态、物理特性以及生物相容性,以制备满足软骨再生领域需求的水凝胶。结果 氨基与醛基比为1:1时,制备出的水凝胶具有良好的孔隙率、适宜的成胶时间、较强的黏附力及稳定的溶胀率等性质,对细胞有良好的生物相容性。结论 氨基与醛基比为1:1时制备出的CMCS/OSA复合水凝胶是软骨组织工程优异的支架材料。     

Mesoporous NiCo2O4 nanoflower constructed from nanosheets as electroactive materials for dye-sensitized solar cells

Binary metal compounds with a spinel structure could improve the electron transport, activating adsorption and active sites for electrocatalytic reaction. Furthermore, the electrocatalytic activity of electroactive materials also depends on their morphology and nanostructure. Herein, this work reported the fabrication of NiCo₂O₄ mesoporous nanoflowers and mesoporous nanospheres and their application as promising counter electrode (CE) electrocatalysts in dye-sensitized solar cells (DSSCs). The as-prepared NiCo₂O₄ mesoporous nanoflower contains abundant open space between nanosheets, generating the 3D porous nanostructure. When investigated as CE materials, NiCo₂O₄ nanoflowers exhibited high charge-transfer ability and intrinsic catalytic activity. The DSSC with NiCo₂O₄ nanoflowers displayed a much higher power conversion efficiency (PCE) of 7.32% than that based on the NiCo₂O₄ nanosphere CE (PCE = 5.58%), even comparable with that of commercial Pt CE (7.54%).

Mesoporous NiCo₂O₄ nanoflower constructed form nanosheets was successfully fabricated and showed efficient electrocatalytic performance as electroactive materials for dye-sensitized solar cells.     

糖尿病心肌病早期诊断指标的研究进展

随着糖尿病发病率的迅速增加,伴有心肌病的糖尿病患者数量也正以惊人的速度增长,然而目前对于糖尿病心肌病早期诊断的生化指标、辅助检查研究仍不充分。早期诊断糖尿病心肌病,对于疾病的防治及预后至关重要。现就糖尿病心肌病早期诊断指标的研究进展进行相关综述。     

The effect of thick fibers and large pores of electrospun poly(ε-caprolactone) vascular grafts on macrophage polarization and arterial regeneration

The vascular grafts prepared by electrospinning often have relatively small pores, which limit cell infiltration into the grafts and hinder the regeneration and remodeling of the grafts into neoarteries. To overcome this problem, macroporous electrospun polycaprolactone (PCL) scaffolds with thicker fibers (5–6 μm) and larger pores (∼30 μm) were fabricated in the present study. In vitro cell culture indicated that macrophages cultured on thicker-fiber scaffolds tended to polarize into the immunomodulatory and tissue remodeling (M2) phenotype, while those cultured on thinner-fiber scaffolds expressed proinflammatory (M1) phenotype. In vivo implantation by replacing rat abdominal aorta was performed and followed up for 7, 14, 28 and 100 d. The results demonstrated that the macroporous grafts markedly enhanced cell infiltration and extracellular matrix (ECM) secretion. All grafts showed satisfactory patency for up to 100 days. At day 100, the endothelium coverage was complete, and the regenerated smooth muscle layer was correctly organized with abundant ECM similar to those in the native arteries. More importantly, the regenerated arteries demonstrated contractile response to adrenaline and acetylcholine-induced relaxation. Analysis of the cellularization process revealed that the thicker-fiber scaffolds induced a large number of M2 macrophages to infiltrate into the graft wall. These macrophages further promoted cellular infiltration and vascularization. In conclusion, the present study confirmed that the scaffold structure can regulate macrophage phenotype. Our thicker-fiber electrospun PCL vascular grafts could enhance the vascular regeneration and remodeling process by mediating macrophage polarization into M2 phenotype, suggesting that our constructs may be a promising cell-free vascular graft candidate and are worthy for further in vivo evaluation.