Injectable extracellular matrix-mimetic hydrogel based on electrospun Janus fibers.

To date, the reported injectable hydrogels have failed to mimic the fibrous architecture of the extracellular matrix (ECM), limiting their biological effects on cell growth and phenotype. Additionally, they lack the micro-sized pores present within the ECM, which is unfavorable for the facile transport of nutrients and waste. Herein, an injectable ECM-mimetic hydrogel (IEMH) was fabricated by shortening and dispersing Janus fibers capable of self-curling at body temperature into pH 7.4 phosphate buffer solution. The IEMH could be massively prepared through a side-by-side electrospinning process combined with ultraviolet irradiation. The IEMHs with only 5 wt% fibers could undergo sol-gel transition at body temperature to become solid gels with desirable stability, sturdiness, and elasticity and self-healing ability. In addition, they possessed notable pseudoplasticity, which is beneficial to injection at room temperature. The results obtained from characterization analysis via scanning electron microscopy, total internal reflection fluorescence microscopy, nuclear magnetic resonance spectroscopy, and Fourier-transform infrared spectroscopy indicate that their sol-gel transition under physiological conditions stems from the synergistic action of the tight entanglements between thermally-induced self-curling fibers and the hydrophobic interaction between the fibers. An MTT assay using C2C12 myoblast cells was performed to examine the in vitro cytotoxicity of IEMHs for biomedical applications, and the cell viability was found to be more than 95%.

Anatomic Restoration of Triple Disruption of the Superior Shoulder Suspensory Complex: A Case Report and Review of the Literature.

BACKGROUND: Multiple disruptions of the superior shoulder suspensory complex (SSSC) involving more than two components are extremely rare. In some extreme situations, three components of the SSSC structure can be involved. The ideal treatment for this type of injury is debatable. CASE PRESENTATION: A 21-year-old woman was referred to our emergency center following a traffic accident. A three-dimensional CT scan showed triple disruption of the SSSC involving concomitant ipsilateral fractures of the coracoid, the acromion, and the distal clavicle. The connection between the upper limber and the axial skeleton was destroyed. There was no evidence of associated injury and the neurovascular examination of the injured upper limb was normal. The patient underwent an open reduction and internal fixation to restore the anatomic integrity of the SSSC. The arm was supported in a broad arm sling for 2 weeks after surgery. Gentle passive range of motion activity under analgesic was encouraged from the second day postoperatively. One year and half after the operation, the patient had regained pain free and unrestricted shoulder stability and mobility. CONCLUSION: The manifestations of multiple disruptions of the SSSC may be variable. This case illustrated the challenges of treating the multiple disruption of the SSSC structure. It also showed that surgical intervention for this rare combination injury yields an excellent functional result. The good outcome achieved in this patient demonstrates that surgical intervention might be an optional resolution for multiple disruptions of the SSSC.

Regulatory effect of microRNA-34a on osteogenesis and angiogenesis in glucocorticoid-induced osteonecrosis of the femoral head.

Glucocorticoid-induced osteonecrosis of the femoral head (GIOFH) is a common and devastating orthopedic disease, and its underlying mechanism remains unclear. The aim of this study was to determine the role of microRNA-34a (mir-34a) in GIOFH. C57 mouse mesenchymal stem cells (mMSCs) and human umbilical vein endothelial cells (HUVECs) were cultured with dexamethasone (Dex). A total of 48 adult rats were treated with glucocorticoids, and after the onset of GIOFH, each femoral head was removed. Mir-34a mimics, an inhibitor and over-expressing lentivirus were used in vitro and in vivo, respectively. Real-time PCR, immunohistochemistry, ELISA, cell proliferation assays, osteoblastic differentiation, and endothelial activity assays were employed to evaluate the effect of mir-34a on mMSCs, osteoblasts, and vascular endothelial cells in glucocorticoid-treated mice. We found that Dex inhibited mMSC proliferation and osteoblastic differentiation, as well as the viability and activity of endothelial cells. Dex also caused osteonecrosis and decreased new vessel formation in vivo. Mir-34a alleviated the inhibitory effects of Dex on mMSCs and osteoblasts, while facilitating its inhibitory effects on endothelial cells. Mir-34a is an important regulator in osteogenesis and angiogenesis, and it might be useful as a therapeutic target for GIOFH. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:417-424, 2018.