Combination of Heel-strike like Mechanical Loading with Deproteinized Cancellous Bone Scaffold Implantation to Repair Segmental Bone Defects in Rabbits.

Under physiological conditions bone defects often occur at mechanical load bearing sites and bone substitutes used for regeneration should be similarly subjected to mechanical loading stress. In this study, we investigated whether a novel heel-strike like mechanical loading method can be used as a complementary therapy to promote bone regeneration following bone substitute grafting. To test this, three groups of rabbits with segmental bone defects in the tibia were implanted with bovine deproteinized cancellous bone scaffold (DCBS), with one group also receiving heel-strike like mechanical loading generated by a rap stress stimulator. From weeks 4-12 post-operation X-ray and micro-CT scanning showed that rabbits receiving combination therapy had significantly more callus at the bone defect. Moreover, bone defects in the combination group were completely replaced with new bone at week 12, while the DCBS implantation alone group healed only partially and rabbits receiving neither DCBS nor mechanical loading developed only small calluses throughout the observation period. Analysis of micro-CT scanning results demonstrated that new bone density in the combination group was significantly higher than the DCBS only group at weeks 4 and 12 (p<0.05). H&E staining results also indicated a significantly higher percentage of new bone in the bone defect area and a lower percentage of residual scaffold in the combination group compared to the DCBS only group (p<0.05). Thus, this heel-strike like mechanical loading method appears to accelerate bone regeneration following substitute implantation by restoring a local mechanical loading environment in segmental bone defects.

[Treatments of stage-Is testicular mixed germ cell tumors: A report of 3 cases].

OBJECTIVE: To investigate different treatment methods for stage-Is testicular mixed germ cell tumors (TMGCTs). METHODS: We retrospectively analyzed the clinical data about 3'cases of stage-Is TMGCTs (aged 26-39 years) treated in the 175th Hospital of PLA, reviewed relevant literature, and explored the clinical characteristics of TMGCTs. RESULTS: Of the 3 patients, 1 was treated by radical orchiectomy, 1 by radical orchiectomy + retroperitoneal lymph node dissection + BEP chemotherapy scheme, and the other by radical orchiectomy + radiotherapy. The pathological components of TMGCTs were immature teratoma, seminoma, spermatocytoma, chorioepithelioma, embryonal carcinoma, and yolk sac tumor. No recurrence or distant metastasis was found during the 24-month follow-up after surgery. CONCLUSION: The diagnosis of TMGCTs primarily depends on physical examination, ultrasonography, MRI, and measurement of serum tumor markers, while its confirmation necessitates pathological examination, and its treatment is basically radical orchiectomy.

The immunomodulatory role of irisin on osteogenesis via AMPK-mediated macrophage polarization.

Bone healing is thought to be closely related to macrophages. Irisin, a cleaved hormone-like myokine, is well known to participate in immunoregulation and regulates bone metabolism. However, whether irisin could influence osteogenesis by affecting macrophage polarization is remain unknown. Here, the present study aims to investigate the potential immunomodulatory role of irisin on macrophages polarization and its subsequent impact on osteogenesis. We demonstrated that irisin increased cell viability without toxic effect in both Raw264.7 macrophages and MC3T3-E1 cells. Furthermore, irisin treatment polarized M0 and M1 macrophages towards M2 phenotype, with increased expression of CD206-APC, ARG-1 and TGF-ß1, and decreased expression of CD86-PE and TNF-α. In addition, the direct co-cultured test of Raw264.7 macrophages and pre-osteoblastic MC3T3-E1 cells showed that irisin-treated M0 and M1 macrophages promoted osteogenesis with obvious formation of mineralized particles. Interestingly, irisin exposure robustly activated AMPK-α signaling, as manifested by increased expression of phosphorylated AMPK-α. Knockdown of AMPK-α by siRNA significantly suppressed the phosphorylation of AMPK-α, abrogated irisin-induced polarization of M2 phenotype, and inhibited the osteogenic ability of Raw264.7 macrophages. Taken together, our findings showed that irisin-induced M2 polarization enhanced osteogenesis in osteoblasts, and this effect might be associated with activation of AMPK.

A review of emerging bone tissue engineering via PEG conjugated biodegradable amphiphilic copolymers.

Defects in bones can be caused by a plethora of reasons, such as trauma or illness, and in many cases, it poses challenges to the current treatment approaches for bone repair. With increasing demand of bone bioengineering in tissue transplant, there is a need to source for sustainable solutions to induce bone regeneration. Polymeric biomaterials have been identified as a promising approach due to its excellent biocompatibility and controllable biodegradability. Specifically, poly(ethylene glycol) (PEG) is one of the most commonly investigated polymer for use in bio-related application due to its bioinertness and versatility. Furthermore, the hydrophilic nature enables it to be incorporated with hydrophobic but biodegradable polymers like, polylactide (PLA) and polycaprolactone (PCL), to create an amphiphilic polymer. This article reviews the recent synthetic strategies available for the construction of PEG conjugated polymeric system, analysis of PEG influence on the material properties, and provides an overview of its application in bone engineering.

Recent development in cell encapsulations and their therapeutic applications.

Chronic and degenerative diseases are the main causes of death in the aging population worldwide. These diseases are currently maintained using long term administration of conventional drugs which are not curative and reduce the life quality of patients. It is urgent to develop new therapeutic approaches for the treatment of these diseases. Cell therapy that involves the injection of viable cell into patients is a promising therapeutic strategy in chronic and degenerative diseases. However, the survival of injected cells in host tissue is limited due to immunoresponse. Cell encapsulation potentially improves treatment approaches using viable cells and overcome the immuno-rejection following cell transplantation. In this review, we first present the main components and their different functions in the cell encapsulation, including semi permeable membrane, types of cells and matrix. Then, the recently developed technologies and approaches employed to encapsulate cells are summarized and compared in benefits and flaws. More importantly, the insights and significance of the encapsulated cells are also discussed in the application of treating various diseases.

Cementless arthroplasty with a distal femoral shortening for the treatment of Crowe type IV developmental hip dysplasia.

BACKGROUND: Severe developmental dysplasia of the hip is a surgical challenge. The purpose of this study is to describe the cementless arthroplasty with a distal femoral shortening osteotomy for Crowe type IV developmental hip dysplasia and to report the results of this technique. MATERIALS AND METHODS: 12 patients (2 male and 10 female) of Crowe type IV developmental hip dysplasia operated between January 2005 and December 2010 were included in the study. All had undergone cementless arthroplasty with a distal femoral shortening osteotomy. Acetabular cup was placed at the level of the anatomical position in all the hips. The clinical outcomes were assessed and radiographs were reviewed to evaluate treatment effects. RESULTS: The mean followup for the 12 hips was 52 months (range 36-82 months). The mean Harris hip score improved from 41 points (range 28-54) preoperatively to 85 points (range 79-92) at the final followup. The mean length of bone removed was 30 mm (range 25-40 mm). All the osteotomies healed in a mean time of 13 weeks (range 10-16 weeks). There were no neurovascular injuries, pulmonary embolism or no infections. CONCLUSION: Our study suggests that cementless arthroplasty with a distal femoral shortening is a safe and effective procedure for severe developmental dysplasia of the hip.