Research progress on biologic repair of rotator cuff injury / 天津医药

Rotator cuff injury is a common shoulder disease,which often results in pain and limited motion of shoulder and reduces the quality of life.There are some limitations for current treatments,which often lead to repair failure or reinjury of rotator cuff.Therefore,a novel repair technique is needed.Biologic repair represents a novel technique in the management of rotator cuff injury,and has the potential to restore the normal histological structure of rotator cuff.Biologic repair involves the application of growth factors and/or cells to promote the regeneration of rotator cuff tendons. This study reviewed the literatures on biologic repair of rotator cuff injury,and presented the research progress.

Differentiation of human umbilical cord-derived mesenchymal stem cells into annulus fibrosus-like cells by co-culture / 临床与实验病理学杂志

Purpose To induce the differentiation of hu-man umbilical cord mesenchymal stem cells ( HUCMSCs) into annulus fibrosus (AF) cells by in vitro co-culture technique and to investigate the morphological and histological changes of HUCMSCs after co-culture. Methods HUCMSCs and AF cells were isolated from the normal neonatal umbilical cord and New Zealand white rabbit. Transwell six-well plates were used for co-culture with the cells seeded at the ratio of 1 ∶ 1, HUCMSCs cultured alone served as controls. After two weeks of co-culture, morphological changes were observed by inverted microscope. Real-time PCR was used to detect the expression of typeⅠcolla-gen, aggrecan and SOX-9 gene in HUCMSCs. Immunocyto-chemical staining and toluidine blue staining were used to detect the synthesis of cell matrix such as type Ⅰ collagen and aggre- can. Results The morphology of HUCMSCs in control group was long-fusiform, the morphology of HUCMSCs in co-culture gradually became short-fusiform or polygonal, and began to ap-pear synapse, showing the morphological features of AF-like cells. Real-time PCR results showed that typeⅠcollagen, aggre-can and SOX-9 mRNA were significantly increased in the co-cul-ture group (P＜0. 05). Immunocytochemical staining and tolui-dine blue staining showed that type I collagen and aggrecan were positive, respectively. Conclusion In vitro co-culture technol-ogy can induce HUCMSCs to differentiate into AF-like cells, which is expected to provide a new kind of seed cells for the bio-logical treatment of degenerative disc disease.

Effects of different decellularization methods on biomechanical properties and histological structure of annulus fibrosus in pigtail / 医用生物力学

Objective To investigate effects of different de-cellularization methods on biomechanical properties and histological structure of annulus fibrosus in pigtails and provide experimental evidence for the construction of tissue engineering annulus fibrosus. Methods Sixty Fresh annulus fibrosus were dissected from caudal disks of pigs and randomly assigned to 4 groups with 15 in each group. Triton X-100 group(Group A): annulus fibrosus were treated with hypotonic Tris-HCl buffer for 48 hours and de-cellularized with Triton X-100, DNase Ⅰ and RNase A. SDS group (Group B): annulus fibrosus were subjected to 3 cycles of freeze-thaw and subsequently de-cellularized with SDS, DNaseⅠ and RNase A. Trypsin group (Group C): annulus fibrosus were de-cellularized with Tris buffer containing trypsin, DNase Ⅰ and RNase A. Control group: fresh annulus fibrosus underwent no treatment. After the de-cellularization process was completed, hematoxylin-eosin (HE) staining was carried out to examine the efficacy on cell removal, and the ultrastructure of annulus fibrosus were observed by scanning electron microscopy. The collagen content, glycosaminoglycan (GAG) content and biomechanical parameters in each group were also detected. Results HE staining and scanning electron microscopy showed that no residual cells were found in Group A, B and C. The structure of annulus fibrosus in Group A was not disturbed, while that in Group B and C was damaged severely and slightly, respectively. There was no statistical difference in collagen content among Group A, B and C, as compared to the control group (P>0.05). But the GAG content was significantly more lower in Group A, B and C than in the control group (P0.05), while these parameters of Group B were lower than those in the control group (P<0.05). Conclusions The Triton X-100-treated annulus fibrosus retained the major extracellular matrix composition after cell removal and preserved the major structure and mechanical strength, which is preferable for the construction of tissue engineering annulus fibrosus.

In vitro cartilage production using an extracellular matrix-derived scaffold and bone marrow-derived mesenchymal stem cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cartilage repair is a challenging research area because of the limited healing capacity of adult articular cartilage. We had previously developed a natural, human cartilage extracellular matrix (ECM)-derived scaffold for in vivo cartilage tissue engineering in nude mice. However, before these scaffolds can be used in clinical applications in vivo, the in vitro effects should be further explored.</p><p><b>METHODS</b>We produced cartilage in vitro using a natural cartilage ECM-derived scaffold. The scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and were characterized by scanning electron microscopy (SEM), micro-computed tomography (micro-CT), histological staining, cytotoxicity assay, biochemical and biomechanical analysis. After being chondrogenically induced, the induction results of BMSCs were analyzed by histology and Immunohisto-chemistry. The attachment and viability assessment of the cells on scaffolds were analyzed using SEM and LIVE/DEAD staining. Cell-scaffold constructs cultured in vitro for 1 week and 3 weeks were analyzed using histological and immunohistochemical methods.</p><p><b>RESULTS</b>SEM and micro-CT revealed a 3-D interconnected porous structure. The majority of the cartilage ECM was found in the scaffold following the removal of cellular debris, and stained positive for safranin O and collagen II. Viability staining indicated no cytotoxic effects of the scaffold. Biochemical analysis showed that collagen content was (708.2-44.7) µg/mg, with GAG (254.7 ± 25.9) µg/mg. Mechanical testing showed the compression moduli (E) were (1.226 ± 0.288) and (0.052 ± 0.007) MPa in dry and wet conditions, respectively. Isolated canine bone marrow-derived stem cells (BMSCs) were induced down a chondrogenic pathway, labeled with PKH26, and seeded onto the scaffold. Immunofluorescent staining of the cell-scaffold constructs indicated that chondrocyte-like cells were derived from seeded BMSCs and excreted ECM. The cell-scaffold constructs contained pink, smooth and translucent cartilage-like tissue after 3 weeks of culture. We observed evenly distributed cartilage ECM proteoglycans and collagen type II around seeded BMSCs on the surface and inside the pores throughout the scaffold.</p><p><b>CONCLUSION</b>This study suggests that a cartilage ECM scaffold holds much promise for in vitro cartilage tissue engineering.</p>

Long-term results and radiographic findings of percutanous vertebroplasties with polymethylmethacrylate for vertebral osteoporotic fractures / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Percutaneous vertebroplasty (PVP) has become a popular procedure for painful vertebral osteoporotic fracture (VOF), with immediate pain relief and improved mobility; however, polymethylmethacrylate (PMMA) injected into the vertebral body is not absorbable and little information is available concerning the long-term results. In this retrospective study, we evaluated the long-term clinical results and radiological changes after PVPs for VOFs.</p><p><b>METHODS</b>Fifty-one patients with VOFs were treated by PVPs with PMMA between 2000 and 2004. After > 7 years of follow-up, eight patients had died from causes unrelated to the intervention and 12 patients were lost to follow-up, thus leaving 31 patients available for evaluation with an average length of follow-up of 9.2 years (follow-up rate, 72.1%). Among these 31 patients, the PMMA was injected at 43 levels with a mean volume of 4.3 ml per level (range, 2 - 6 ml). The pain was assessed with a visual analog scale (VAS), and the mobility was graded as walking without difficulty (grade 1), walking with assistance (grade 2), and bedridden (grade 3). Plain radiographs and computed tomography (CT) were obtained and assessed pre-operatively, immediately post-operatively, and after 7 years of follow-up. The PMMA, vertebral height, and Cobb angle were assessed and compared.</p><p><b>RESULTS</b>All of the patients experienced pain relief and improved mobility after intervention and during the follow-up period. Cement leakage was detected in post-operative CT scans in 9 of 51 patients, but without neurological compromise. For the 31 patients followed up over 7 years, the VAS decreased from 8.3 ± 2.6 pre-operatively, to 2.1 ± 1.6 immediately post-operatively, and 1.0 ± 0.9 at the final follow-up evaluation, with significantly improved mobility. Additional compression fractures occurred at adjacent levels in three patients, and there were no new fractures at the augmented vertebrae. Based on a review of the radiographs, neither loose nor displaced cement was detected. The changes in vertebral height and Cobb angle were not significant. On CT scans, the cement closely contacted or infiltrated the trabecular bone. The boundary between the cement and trabecular bone was indistinct and there was no evident radiolucent gap between the cement and trabecular bone.</p><p><b>CONCLUSIONS</b>At an average follow-up of 9.2 years, PVPs provided sustained pain relief and improved mobility in patients with VOFs. The PMMA injected into the vertebral body combined closely with the host trabecular bone without adverse reactions.</p>

Diagnostic features of pathological fractures located in extremities caused by bone tumor or tumor like lesion / 中华骨科杂志

ObjectiveTo explore the clinical characteristics of pathological fracture in extremities caused by bone tumors or tumor-like lesions. MethodsFrom August 2002 to December 2010, 139 patients with pathological fractures were entered in the study, including 79 males and 60 females with an average age of 31.1 years. Fractures included tumor-like lesion in 55 cases, benign tumor in 13, giant cell tumor (GCT)in 7, primary malignant tumors in 28, and metastatic tumors in 36. Forces induced to fractures were classified into four grades: spontaneous fracture, functional activity, minor injury, severe injury. Age, fracture location, histological results, fractures forces, prodromes, and misdiagnosis were all observed. Chi-square test were use to compare forces and prodromes within different tumors. ResultsThe highest morbidity rate is 32.4％(45/139) which lies in 11-20 years old. The cites of fractures including femurs in 71 cases, humerus in 36, tibia in 15, fingers in 7, radiuses in 4, fibula in 3, ulnas in 2, and metatarsus in 1. Fracture forces include spontaneous fractures in 29 cases, functional activity in 42, minor injuries in 65, and traumatic injuries in 3. Sixty-seven patients(48.2％) had local prodromes. The prodromes of both malignant tumors and metastatic tumors were more than benign tumors. Twenty cases experienced misdiagnosis with average delay time of 12 weeks. ConclusionMinor injury forces and local prodromes are clinical key features of pathological fractures. Both of them are key points of avoiding misdiagnosis.

Evaluation of an extracellular matrix-derived acellular biphasic scaffold/cell construct in the repair of a large articular high-load-bearing osteochondral defect in a canine model / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Osteochondral lesion repair is a challenging area of orthopedic surgery. Here we aimed to develop an extracellular matrix-derived, integrated, biphasic scaffold and to investigate the regeneration potential of the scaffold loaded with chondrogenically-induced bone marrow-derived mesenchymal stem cells (BMSCs) in the repair of a large, high-load-bearing, osteochondral defect in a canine model.</p><p><b>METHODS</b>The biphasic scaffolds were fabricated by combining a decellularization procedure with a freeze-drying technique and characterized by scanning electron microscopy (SEM) and micro-computed tomography (micro-CT). Osteochondral constructs were fabricated in vitro using chondrogenically-induced BMSCs and a biphasic scaffold, then assessed by SEM for cell attachment. Osteochondral defects (4.2 mm (diameter) × 6 mm (depth)) were created in canine femoral condyles and treated with a construct of the biphasic scaffold/chondrogenically-induced BMSCs or with a cell-free scaffold (control group). The repaired defects were evaluated for gross morphology and by histological, biochemical, biomechanical and micro-CT analyses at 3 and 6 months post-implantation.</p><p><b>RESULTS</b>The osteochondral defects of the experimental group showed better repair than those of the control group. Statistical analysis demonstrated that the macroscopic and histologic grading scores of the experimental group were always higher than those of the control group, and that the scores for the experimental group at 6 months were significantly higher than those at 3 months. The cartilage stiffness in the experimental group (6 months) was (6.95 ± 0.79) N/mm, 70.77% of normal cartilage; osteochondral bone stiffness in the experimental group was (158.16± 24.30) N/mm, 74.95% of normal tissue; glycosaminoglycan content of tissue-engineered neocartilage was (218 ± 21.6) µg/mg (dry weight), 84.82% of native cartilage. Micro-CT analysis of the subchondral bone showed mature trabecular bone regularly formed at 3 and 6 months, with no significant difference between the experimental and control groups.</p><p><b>CONCLUSION</b>The extracellular matrix-derived, integrated, biphasic scaffold shows potential for the repair of large, high-load-bearing osteochondral defects.</p>

Application of minimal access in spinal surgery / 上海第二医科大学学报

Minimal access spinal surgery(MASS),a new minimally invasive technique,has been developed on the basis of classic minimally invasive spinal surgery(MISS).With some special equipments,this procedure can reduce approach-related morbidity and collateral damage to surrounding tissues,and can be performed under direct visualization of the spine.The MASS combines the merits of MISS and traditional open procedures,and comparable results can be obtained while decreasing approach-related complications and learning curve.Now,the application of MASS has become more frequent in clinical practice due to its favourable characteristics in curative effect,postoperative recovery and economic efficacy.