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As a promising alternative to autologous nerve grafts, tissue-engineered nerve grafts have been extensively studied as a way to bridge peripheral nerve defects and guide nerve regeneration. The main difference between autogenous nerve grafts and tissue-engineered nerve grafts is the regenerative microenvironment formed by the grafts. If an appropriate regenerative microenvironment is provided, the repair of a peripheral nerve is feasible. In this study, to mimic the body’s natural regenerative microenvironment closely, we co-cultured Schwann cells (SCs) and adipose-derived stem cells (ADSCs) as seed cells and introduced them into a silk fibroin (SF)/collagen scaffold to construct a tissue-engineered nerve conduit (TENC). Twelve weeks after the three different grafts (plain SF/collagen scaffold, TENC, and autograft) were transplanted to bridge 1-cm long sciatic nerve defects in rats, a series of electrophysiological examinations and morphological analyses were performed to evaluate the effect of the tissue-engineered nerve grafts on peripheral nerve regeneration. The regenerative outcomes showed that the effect of treatment with TENCs was similar to that with autologous nerve grafts but superior to that with plain SF/collagen scaffolds. Meanwhile, no experimental animals had inflammation around the grafts. Based on this evidence, our findings suggest that the TENC we developed could improve the regenerative microenvironment and accelerate nerve regeneration compared to plain SF/collagen and may serve as a promising strategy for peripheral nerve repair. [ABSTRACT FROM AUTHOR]

Purpose: Gemcitabine, a third-generation anticancer agent, has been shown to be active in several solid tumors. High-grade hemorrhage (grade≥3) has been reported with this drug, although the overall risk remains unclear. We conducted a meta-analysis of randomized controlled trials evaluating the incidence and risk of high-grade hemorrhage associated with gemcitabine. Methods: Pubmed was searched for articles published from January 1, 1990 to December 31, 2012. Eligible studies included prospective randomized controlled phase II and III trials evaluating gemcitabine-based vs non-gemcitabine-based therapy in patients with solid tumors. Data on high-grade hemorrhage were extracted. Overall incidence rates, relative risk (RR), and 95% confidence intervals (CI) were calculated employing fixed- or random-effects models depending on the heterogeneity of included trials. Results: A total of 6433 patients from 20 trials were included. Among patients treated with gemcitabine-based chemotherapy, the overall incidence of high-grade hemorrhage was 1.7% (95%CI: 0.9–3.1%), and the RR of high-grade hemorrhage was 2.727 (95%CI: 1.581–4.702, p<0.001). Exploratory subgroup analysis revealed the highest RR of hemorrhage in non-small-cell lung cancer (NSCLC) patients (RR: 3.234; 95%CI, 1.678–6.233; p<0.001), phase II trials (RR 7.053, 95%CI: 1.591–31.27; p = 0.01), trials reported during 2006–2012 (RR: 3.750; 95%CI: 1.735–8.108, p<0.001) and gemcitabine used as single agent (RR 7.48; 95%CI: 0.78–71.92, p = 0.081). Conclusion: Gemcitabine is associated with a significant increase risk of high-grade hemorrhage in patients with solid tumors when compared with non-gemcitabine-based therapy. [ABSTRACT FROM AUTHOR]

Mechanical strain plays a critical role in the proliferation, differentiation and maturation of bone cells. As mechanical receptor cells, osteoblasts perceive and respond to stress force, such as those associated with compression, strain and shear stress. However, the underlying molecular mechanisms of this process remain unclear. Using a four-point bending device, mouse MC3T3-E1 cells was exposed to mechanical tensile strain. Cell proliferation was determined to be most efficient when stimulated once a day by mechanical strain at a frequency of 0.5 Hz and intensities of 2500 µε with once a day, and a periodicity of 1 h/day for 3 days. The applied mechanical strain resulted in the altered expression of 1992 genes, 41 of which are involved in the mitogen-activated protein kinase (MAPK) signaling pathway. Activation of ERK by mechanical strain promoted cell proliferation and inactivation of ERK by PD98059 suppressed proliferation, confirming that ERK plays an important role in the response to mechanical strain. Furthermore, the membrane-associated receptors integrin β1 and integrin β5 were determined to regulate ERK activity and the proliferation of mechanical strain-treated MC3T3-E1 cells in opposite ways. The knockdown of integrin β1 led to the inhibition of ERK activity and cell proliferation, whereas the knockdown of integrin β5 led to the enhancement of both processes. This study proposes a novel mechanism by which mechanical strain regulates bone growth and remodeling.