Objective To study biological rule of recombinant human bone morphogenetic protein 2 (rhBMP-2) in regulating the expression of vascular endothelial growth factor (VEGF) of adipose-derived stem cells (ADSCs) at different induced concentrations and time points at gene level and protein level. Methods ADSCs were separated from adult human adipose tissues and cultured until passage 3. After ADSCs were induced by rhBMP-2 in concentrations of 0, 50, 100, and 200 ng/ mL respectively for 24 hours, and by 100 ng/mL rhBMP-2 for 3, 6, 12, 18, 24, 36, and 48 hours (ADSCs were not induced at corresponding time point as controls) respectively, the VEGF mRNA and protein expressions were detected by RT-PCR and ELISA. Results The VEGF mRNA and protein expressions induced by rhBMP-2 were concentration-dependent; the expressions were highest in a concentration of 100 ng/mL. The VEGF mRNA expression in concentrations of 50, 100, and 200 ng/mL were significantly higher than that in a concentration of 0 ng/mL (P lt; 0.05); and the expression in concentration of 100 ng/ mL was significantly higher than that in concentrations of 50 and 200 ng/mL (P lt; 0.05). The VEGF protein expression in a concentration of 100 ng/mL was significantly higher than that in the other concentrations (P lt; 0.05). The VEGF mRNA and protein expressions induced by rhBMP-2 were time-dependent. The VEGF mRNA and protein expressions at 3 and 6 hours after induction were significantly lower than those of non-induced ADSCs (P lt; 0.05); the expressions were lower at 12 hours after induction, showing no significant difference when compared with those of non-induced ADSCs (P gt; 0.05); the expressions reached peak at 18 and 24 hours after induction, and were significantly higher than those of non-induced ADSCs (P lt; 0.05); the expressions decreased in induced and non-induced ADSCs at 36 and 48 hours, showing no significant difference between induced and non-induced ADSCs (P gt; 0.05). Conclusion rhBMP-2 adjusts VEGF expression of ADSCs in a concentration- and time-dependent manner. The optimum inductive concentration of rhBMP-2 is 100 ng/mL, induced to 18-24 hours is a key period when rhBMP-2 is used to promote tissue engineering bone vascularization.
Objective To assess the effectiveness of surgical interventions for lumbar isthmic spondylolisthesis in adults.Methods RCTs of surgical treatment for adult lumbar isthmic spondylolisthesis were identified from specialized trials registered in Cochrane Back Group, The Cochrane Library (Issue 2, 2004)，additional electronic search (including MEDLINE (1966 to 2004)，EMBASE (1980 to 2004) and CBM), handsearching for Chinese journals. Two reviewers assessed the quality of the trials and extracted data independently. Meta analysis was conducted using RevMan 4.2. Results Four published trials including a total of 277 patients were included. Three trials compared different operative procedures and one trial considered conservative versus surgical treatment for lumbar isthmic spondylolisthesis in adults. Two trials had limitations of trial design which at times gave considerable potential for bias. As very few studies and patients were included, and different score criteria were used to assess the clinical outcomes in the review, we decided to provide a descriptive summary only. All trials drew a conclusion that lumbar posterolateral fusion for adult isthmic spondylolisthesis could relieve pain and improve clinical outcome. There was no significant difference in fusion rate and improvement of clinical outcomes between different operative procedures. One trial showed that the lumbar posterolateral fusion could improve function and relieve pain more efficiently than an exercise program. Three trials indicated there was no difference in fusion rate and improvement of clinical outcomes between different operative methods. One trial suggested that instrumented posterolateral fusion did not improve fusion rate but increased complication rates, operation time and bleeding loss. Two trials considered the role of decompressive laminectomy and reached a conflicting conclusion. Conclusions There is no adequate evidence about the most effective technique of treatment for adult lumbar isthmic spondylolisthesis. There is limited evidence that the lumbar posterolateral fusion for adult isthmic spondylolisthesis can efficiently relieve pain and improve clinical outcome. There is no evidence that the use of pedicle screw fixation can improve the fusion rate or the clinical outcome. At present, there is no enough evidence available from randomised trials to support the routine clinical use of instrumented fusion for lumbar isthmic spondylolisthesis in adults. As very few studies and patients were included in the review, it was cautious to draw any conclusions from the review. More trials with high quality on methodology are needed.