Bridging large gaps in the injured spinal cord: mechanical and biochemical tissue adaptation

Incidence and consequences of spinal cord injuries： World- wide, every year 250,000-500,000 people suffer from spinal cord injury （SCI; www.who.int, 2013）. Traumatic lesions of the spinal cord lead to primary and secondary injury mechanisms, which result in axon damage, loss of signal conduction, demyelination of axons and long-lasting deficits in motor and sensory func- tion. The extent of the damage and the subsequent functional loss depend on the spinal level and the severity of the primary injury. Furthermore, pathophysiological and pathomorpholog- ical responses in acute and chronic SCI share similar but also different requirements for treatment.

Application of bioactive hydrogels combined with dental pulp stem cells for the repair of large gap peripheral nerve injuries

Due to the limitations in autogenous nerve grafting or Schwann cell transplantation,large gap peripheral nerve injuries require a bridging strategy supported by nerve conduit.Cell based therapies provide a novel treatment for peripheral nerve injuries.In this study,we first experimented an optimal scaffold material synthesis protocol,from where we selected the 10%GFD formula(10%GelMA hydrogel,recombinant human basic fibroblast growth factor and dental pulp stem cells(DPSCs))to fill a cellulose/soy protein isolate composite membrane(CSM)tube to construct a third generation of nerve regeneration conduit,CSM-GFD.Then this CSM-GFD conduit was applied to repair a 15-mm long defect of sciatic nerve in a rat model.After 12 week post implant surgery,at histologic level,we found CSM-GFD conduit could regenerate nerve tissue like neuron and Schwann like nerve cells and myelinated nerve fibers.At physical level,CSM-GFD achieved functional recovery assessed by a sciatic functional index study.In both levels,CSM-GFD performed like what gold standard,the nerve autograft,could do.Further,we unveiled that almost all newly formed nerve tissue at defect site was originated from the direct differentiation of exogeneous DPSCs in CSM-GFD.In conclusion,we claimed that this third-generation nerve regeneration conduit,CSM-GFD,could be a promising tissue engineering approach to replace the conventional nerve autograft to treat the large gap defect in peripheral nerve injuries.

The Income Gap GROWS Large

The income gap between regions, urban and rural areas, industries and various social groups is widening in China. The gap, as indicated by the Gini Coefficient, extended beyond an alarming level. A World Bank report said the Gini Coefficient for China surged to 0.47 in 2009, exceeding the "red line" of 0.4. The problems caused by the rising income disparity have been the focus of public attention. Some experts believe that it is high time for China to shrink this income gap. A Xinhua News Agency research team recently analyzed this trend, and published an article in the Economic Information Daily. Edited excerpts follow: