The regulation and functions of the matricellular CCN proteins induced by shear stress.

Shear stress is a frictional drag generated by the flow of fluid, such as blood or interstitial fluid, and plays a critical role in regulating cellular gene expression and functional phenotype. The matricellular CCN family proteins are dynamically regulated by shear stress of different flow patterns, and their expression significantly alters the microenvironment of cells. Secreted CCN proteins mainly bind to several cell surface integrin receptors to mediate their diverse functions in regulating cell survival, function, and behavior. Gene-knockout studies indicate major functions of CCN proteins in the cardiovascular and skeletal systems, the two primary systems in which CCN expressions are regulated by shear stress. In the cardiovascular system, the endothelium is directly exposed to vascular shear stress. Unidirectional laminar blood flow generates laminar shear stress, which promotes a mature endothelial phenotype and upregulates anti-inflammatory CCN3 expression. In contrast, disturbed flow generates oscillatory shear stress, which induces endothelial dysfunction through the induction of CCN1 and CCN2. Shear-induced CCN1 binds to integrin α6ß1 and promotes superoxide production, NF-κB activation, and inflammatory gene expression in endothelial cells. Although the interaction between shear stress and CCN4-6 is not clear, CCN 4 exhibits a proinflammatory property and CCN5 inhibits vascular cell growth and migration. The crucial roles of CCN proteins in cardiovascular development, homeostasis, and disease are evident but not fully understood. In the skeletal system, mechanical loading on bone generates shear stress from interstitial fluid in the lacuna-canalicular system and promotes osteoblast differentiation and bone formation. CCN1 and CCN2 are induced and potentially mediate fluid shear stress mechanosensing in osteocytes. However, the exact roles of interstitial shear stress-induced CCN1 and CCN2 in bone are still not clear. In contrast to other CCN family proteins, CCN3 inhibits osteoblast differentiation, although its regulation by interstitial shear stress in osteocytes has not been reported. The induction of CCN proteins by shear stress in bone and their functions remain largely unknown and merit further investigation. This review discusses the expression and functions of CCN proteins regulated by shear stress in physiological conditions, diseases, and cell culture models. The roles between CCN family proteins can be compensatory or counteractive in tissue remodeling and homeostasis.

Aqueous extract of Arctium lappa L. root (burdock) enhances chondrogenesis in human bone marrow-derived mesenchymal stem cells.

BACKGROUND: Arctium lappa L. root (burdock root) has long been recommended for the treatment of different diseases in traditional Chinese medicine. Burdock root possesses anti-oxidative, anti-inflammatory, anti-cancer, and anti-microbial activities. The aim of the study was to elucidate whether aqueous extract of burdock root regulates mesenchymal stem cell proliferation and differentiation. METHODS: Human bone marrow-derived mesenchymal stem cells in 2D high density culture and in 3D micromass pellets were treated with chondrogenic induction medium and chondral basal medium in the absence or presence of aqueous extract of burdock root. The chondrogenic differentiation was accessed by staining glucosaminoglycans, immunostaining SOX9 and type II collagen and immuonblotting of SOX9, aggrecan and type II collagen. RESULTS: Treatment of aqueous extract of burdock root increased the cell proliferation of hMSCs. It did not have significant effect on osteogenic and adipogenic differentiation, but significantly enhanced chondrogenic induction medium-induced chondrogenesis. The increment was dose dependent, as examined by staining glucosaminoglycans, SOX9, and type II collagen and immunobloting of SOX9, aggrecan and type II collagen in 2D and 3D cultures. In the presence of supplemental materials, burdock root aqueous extract showed equivalent chondrogenic induction capability to that of TGF-ß. CONCLUSIONS: The results demonstrate that aqueous extract of Arctium lappa L. root promotes chondrogenic medium-induced chondrogenic differentiation. The aqueous extract of burdock root can even be used alone to stimulate chondrogenic differentiation. The study suggests that the aqueous extract of burdock root can be used as an alternative strategy for treatment purposes.

Heterotopic ossification with femoral vein compression mimicking deep vein thrombosis.

Heterotopic ossification (HO) in patients with spinal cord injury could lead to local tissue swelling and sometimes mimic the clinical presentation of deep vein thrombosis. Recognition and effective management is critical. We report the case of a bedridden patient with spinal cord injury presenting with diffuse right lower limb swelling caused by external venous compression from HO. The patient underwent surgery and local radiation therapy. Postoperative venography disclosed a marked improvement in the blood flow, and symptoms were alleviated. We discuss the role of venography in the diagnosis and treatment of venous compression in the setting of HO.

Irreducible Elbow Dislocation Associated with Hill-Sachs-like Lesion over the Capitellum.

Irreducible dislocation of the elbow is an uncommon event. We present the case of a posterolateral elbow dislocation after a fall injury in a 67-year-old woman. A closed reduction performed in the emergency department was unsuccessful since the limited passive range of motion resulted in difficulty to perform longitudinal traction and flexion. Computed tomography images showed that the posterolateral aspect of the capitellum was impacted by the tip of the coronoid process, thus appearing similar to the Hill-Sachs lesion in the humeral head. Subsequent open reduction of the elbow revealed the dislocation to be irreducible since the tip of the coronoid process had wedged into a triangular Hill-Sachs-like lesion in the capitellum. The joint was reduced by providing distal traction on the forearm, and main fragments were disengaged using digital pressure. At the 3-month follow-up, the patient reported no dislocations, and had an acceptable range of motion. Thus, we propose that to avoid iatrogenic injury to the joint or other nearby structures, irreducible dislocations should not be subjected to repeated manipulation.

Pathological fractures in predicting clinical outcomes for patients with osteosarcoma.

BACKGROUND: Studies reported contradictory results for the prognostic significance of a pathological fracture in osteosarcoma patients. The aim of this study is to report the outcomes for a cohort of patients with osteosarcoma who presented with and without pathological fractures and to identify the prognostic importance of pathological fracture in predicting outcomes and influences on survival. METHODS: Data of patients with osteosarcoma were retrospectively reviewed. Between March 1992 and June 2014, a total of 268 patients with osteosarcoma were included in this analysis, of whom 34 (12.7%) with fractures at diagnosis or sustained after chemotherapy and 234 (87.3%) without fracture. All patients were treated with approaches that integrated chemotherapy and surgical resections to maximal extent of all sites whenever feasible. The association between potential prognostic factors and survival for these patients were analyzed and compared. RESULTS: No significant difference was observed in overall survival, progression free survival, and disease free survival between osteosarcoma patients with pathological fractures and without fracture. The patients without fracture had a 5-year survival of 50% and 10-year survival of 21%, in contrast to 37% (5-year) and 22% (10-year) in patients with fractures. Lung metastasis was the significant predictor for the presence of fractures. Advanced stage (III) of tumor, lung metastasis, poor response to chemotherapy, and local recurrence were associated increased risk for death in all osteosarcoma patients. CONCLUSION: Pathological fracture is not a predictor of worse survival in this study. Further studies with matched cases are needed to confirm our observations.

Total Hip Arthroplasty for Patients Who Have Ankylosing Spondylitis: Is Postoperative Irradiation Required for Prophylaxis of Heterotopic Ossification?

Postoperative radiation for prevention of heterotopic ossification (HO) has been proven effective for the patients with ankylosing spondylitis (AS) after total hip arthroplasties (THA). This study aims to evaluate the effect of postoperative radiation in HO formation following THA in patients with AS. We retrospectively reviewed 129 hips from 91 patients with AS receiving primary THA from July 2004 to December 2012. There were total 38 patients (53 hips) did not receive postoperative prophylaxis in Group I. Moreover, 53 patients (76 hips) received postoperative single-fraction radiotherapy of 500 cGy in Group II. After a minimum 12-month follow-up, there was no significant difference in HO formation between the two groups (P=0.210). This study suggests that postoperative radiation may not be necessary in Asian patients.