Porous shape memory scaffold of dextran and hydroxyapatite for minimum invasive implantation for bone tissue engineering applications.

Minimally invasive implantation of a porous scaffold of large volume into bone defect site remains a challenge. Scaffolds based on shape memory polymer (SMP) show potential to be delivered in the compact form via minimally invasive surgery. The present study chooses poly (ε-caprolactone)-diols (PCL-diols) as the SMP to cross-link carboxyl dextran via ester bonds together with particle leaching method to yield a porous SMP scaffold. The inner surfaces of porous SMP scaffold are then mineralized via in situ precipitation to yield mineralized porous SMP-hydroxyapatite (SMP-HA) scaffold. The porous SMP-HA scaffold possesses pore size of 400-500 µm, with HA particles uniformly distributed and orientationally aligned on the inner surfaces of scaffold. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) are carried out to identify the HA deposition. The phase transition temperature of the scaffold is adjusted to 38°C via changing the dosage of PCL (molecule weight: 2800) to endow the scaffold with shape deformation and fixed properties, as well as well-performed shape recovery property under body temperature. Bone marrow mesenchymal stem cells (BMSCs) adhere on the inner surfaces of SMP-HA scaffold, exhibiting larger spreading area when compared to cells adhered on SMP scaffold without HA, promoting its osteogenesis. In vivo degradation showed that the scaffold degrades completely after 6 months post-implantation. At the same time, significant tissue and capillary invasion indicated that the present porous SMP-HA scaffold hold great promise towards bone tissue engineering applications.

Inhibition of Src by microRNA-23b increases the cisplatin sensitivity of chondrosarcoma cells.

Chondrosarcomas are malignant cartilage-forming tumors from low-grade to high-grade aggressive tumors characterized by metastasis. Cisplatin is an effective DNA-damaging anti-tumor agent for the treatment against a wide variety of solid tumors. However, chondrosarcomas are notorious for their resistance to conventional chemo- and radio- therapies. In this study, we report miR-23b acts as a tumor suppressor in chondrosarcoma. The expressions of miR-23b are down-regulated in chondrosarcoma patient samples and cell lines compared with adjacent normal tissues and human primary chondrocytes. In addition, overexpression of miR-23b suppresses chondrosarcoma cell proliferation. By comparison of the cisplatin resistant chondrosarcoma cells and parental cells, we observed miR-23b was significantly down regulated in cisplatin resistant cells. Moreover, we demonstrate here Src kinase is a direct target of miR-23b in chondrosarcoma cells. Overexpression of miR-23b suppresses Src-Akt pathway, leading to the sensitization of cisplatin resistant chondrosarcoma cells to cisplatin. This chemo-sensitivity effect by the miR-23b-mediated inhibition of Src-Akt pathway is verified with the restoration of Src kinase in miR-23b-overespressing chondrosarcoma cells, resulting in the acquirement of resistance to cisplatin. In summary, our study reveals a novel role of miR-23b in cisplatin resistance in chondrosarcoma and will contribute to the development of the microRNA-targeted anti-cancer therapeutics.

Langerhans cell histiocytosis of spine: a comparative study of clinical, imaging features, and diagnosis in children, adolescents, and adults.

BACKGROUND CONTEXT: Langerhans cell histiocytosis (LCH) of the spine has been well documented in the literature, but most studies concern management of the disease. No focused report on the differences in clinical and radiographic features of spinal LCH among children, adolescents, and adults exists. PURPOSE: To review and stress the clinical and imaging differences of spinal LCH in children, adolescents, and adults to avoid false diagnosis. STUDY DESIGN: A retrospective study of children and adults with LCH of the spine. PATIENT SAMPLE: Consecutive patients treated at our institution. OUTCOME MEASURES: Visual analog scale for pain, Frankel scale for neurologic status, and X-ray, computed tomography (CT) and magnetic resonance imaging (MRI) for imaging. METHODS: Seventy-six patients with pathology-proven LCH involving the spine were treated at our institution between 1996 and 2010. Only patients with spine involvement pathologically and/or radiographically were included. Two groups were identified based on the age. Group I comprised children and adolescents (age <18 years; n=40) and Group II comprised adults (age ≥18 years; n=36). Analysis included age and gender distribution, clinical presentation, and imaging features and diagnosis. Pathologic diagnosis was performed by needle or open biopsy of the lesions. RESULTS: Of the 76 patients, 55 were male and 21 were female (ratio of 2.62:1). Neck or back pain was the most common symptom in all patients and was the only presenting symptom in some patients. Restricted motion of spine was the most frequent symptom secondary to pain. Thirty-seven patients presented with neurologic symptoms. Adult patients were more likely to suffer neurologic deficits (p<.005). The distribution of lesions revealed predominance in the cervical spine, followed by thoracic and lumbosacral spine. Plain radiology of children and adolescents with spinal LCH usually revealed a typical vertebral plana, but the adult patients represented different severity of vertebral collapse without typical features. The images of CT scans between the two groups were similar, and all revealed lytic lesions in vertebral bodies and/or posterior elements. In Group I, lesions showed hypointense on T1-weighted images in 15 cases and isointense in 25 cases. Nineteen patients presented as intermediate to slight high signal on T2-weighted images, and the remaining patients presented as hyperintense on T2-weighted images. In Group II, lesions showed hypointense on T1-weighted images in 29 cases, isointense on T1-weighted images in seven cases, and hyperintense on T2-weighted images in 36 cases. Paraspinal soft tissue mass was detected in 28 and 23 cases in Group I and Group II, respectively. Fifteen children and adolescent patients versus 23 adult patients had epidural spinal cord compression. Oversleeve-like or dumbbell sign was observed in 21 cases in Group I but only in four cases in Group II. CONCLUSIONS: The most common clinical manifestations of LCH of the spine were neck or back pain, followed by restricted motion of spine, neurologic symptoms, and deformity. Neurologic deficits were more frequent in adult patients. Vertebral plana is the typical imaging feature in children and adolescent patients but seldom in adults. Computed tomography is best for characterizing anatomy of the involved vertebra, and MRI is best for delineating marrow and soft tissue. The oversleeve-like sign on MRI may be a feature of spinal LCH as well as vertebra plana in children and adolescents. Needle biopsy under CT guidance should be performed before a treatment strategy is determined.

Eosinophilic granuloma of spine in adults: a report of 30 cases and outcome.

BACKGROUND: Eosinophilic granuloma (EG) of the spine is rare, especially in adults. There had been few large and long-term studies reported in the literature. The management goals of this disease in adults are preservation of neurologic function, relief of pain and reconstruction of spinal stability. However, there are still controversies over appropriate management modality of eosinophilic granuloma. METHODS: Clinical manifestations, radiographic presentations, therapeutic outcomes and follow-up findings of 30 adults who were histiologically diagnosed with spinal eosinophilic granuloma, including 28 patients who received surgical treatment at our institutions from 1985 to 2008 were reviewed retrospectively. RESULTS: There were 25 males and five females with a mean age of 34.5 years (range, 18-71 years). The post-operative follow-up period ranged from 2 to 22.4 years (mean, 8.3 years). Neurologic deficits developed in 21 patients, apparent kyphosis developed in four cases. In contrast to the classic feature of vertebra plana in children, we found that more severe lesions often led to asymmetric collapse in adult patients and only three patients presented with vertebra plana. Thirty-three vertebral lesions distributed throughout the spine column. Twenty-one lesions were in cervical spine, seven in the thoracic spine and five in the lumbar spine. Twenty-eight adult patients underwent surgical resection with or without chemotherapy or radiotherapy, and four (13.3%) patients had recurrence after surgery. No patient in our series died. CONCLUSIONS: The onset of spinal EG is insidious and mainly presents as osteolytic destruction. There is a particular high prevalence of lesions in the cervical spine and more severe lesions often led to asymmetric collapse. As the skeleton of adults is well-developed and the epiphysis has stopped growing, individualized management including surgical intervention should be considered in adult patients with spinal EG who present with neurological damage and spinal instability.

[Surgical treatment and prognosis of aneurysmal bone cyst in mobile spine].

OBJECTIVE: To investigate the effects of surgical treatment and prognosis of aneurysmal bone cyst (ABC) in mobile spine. METHODS: A total of 12 patients with ABC were operated on from 1996 to 2006, and the clinical data were retrospectively reviewed. The patients included 7 male and 5 female, aged from 16 to 52 years (mean, 29 years). Surgical interventions were selected according to WBB criteria. Seven patients underwent total spondylectomy, four underwent resection of posterior arch, one patient received sagittal resection only. Anti-poster or post-lateral approach reconstruction with bone-graft or bone cement and transpedicular screws fixation were performed in the cases. Eight cases received radiotherapy after the operation. RESULTS: The mean operation blood lose was 3210 ml. The patients were followed-up for 10 to 116 months (mean, 41.8 months). Seven patients got complete recover of spinal cord function, 4 patients experienced local recurrence in 1-2 years post operation. One patient died of multiple metastasis of chondrosarcoma after radiotherapy. CONCLUSIONS: ABC in spine is an aggressive disease with high local recurrence rate. Enbloc if possible provides the best result, with excellent prognosis. Radiotherapy should be selected carefully.