嗅鞘细胞移植治疗脊髓损伤:理论研究的进展

学术背景:一般认为中枢神经系统损伤后,由于内在的再生能力差和外在环境抑制,损伤轴突不能再生。近年来研究证实脊髓损伤后采用一些改变其局部环境的方法,能促使损伤神经修复、再生及恢复脊髓部分神经功能。目的:移植的嗅鞘细胞通过加速轴突穿过受损脊髓的区域,从而恢复部分神经功能,有必要对嗅鞘细胞移植治疗脊髓损伤的基础和临床研究现状进行深入认识。检索策略:由该论文的研究人员应用计算机检索Pubmed数据库1994-01/2007-07的相关文献,检索词"spinal cord injury,Olfactory Ensheathing Cells,Neumtrophic Factors",并限定文章语言种类为English。同时计算机检索中国期刊全文数据库2000-01/2007-07的相关文献,检索词"嗅鞘细胞,脊髓损伤",并限定文章语言种类为中文。共检索到76篇文献,对资料进行初审,纳入标准:①文章所述内容应与嗅鞘细胞移植治疗脊髓损伤密切相关。②同一领域选择近期发表或在权威杂志上发表的文章。排除标准:①重复性研究。②Meta分析。文献评价:文献的来源主要是通过对嗅鞘细胞移植治疗脊髓损伤方面内容进行汇总分析。所选用的34篇文献中,4篇为综述,其余均为临床或基础实验研究。资料综合:①大量的基础和临床研究显示:脊髓损伤后采用一些改变其局部环境的方法,能促使损伤神经修复、再生和恢复脊髓部分冲经功能。在这些方法中,嗅鞘细胞被认为是治疗脊髓损伤最有前景的方法之一。②嗅鞘细胞具有许旺细胞和星形胶质细胞相似的特征,在其膜上表达出很多与细胞黏合和轴突生长相关的分子,还能分泌大量不同种类的神经营养和支持因子;实验证实嗅鞘细胞移植入各种脊髓损伤的模型表现出促进脊髓轴突再生的能力。③临床研究证实,嗅鞘细胞移植对脊髓损伤患者的脊髓神经功能恢复具有帮助作用,且安全性有保障。结论:采用嗅鞘细胞移植治疗脊髓损伤已被公认为非常有效且前景广阔的治疗方法之一。目前采用嗅鞘细胞移植治疗的晚期脊髓损伤患者为数尚少,还需要进一步观察研究其最终恢复程度和临床安全性;此外仍需探讨如何提高脊髓神经功能恢复的程度。     

Time-dependent association between metabolic syndrome and risk of CKD in Korean men without hypertension or diabetes

BACKGROUND: The time-dependent association between metabolic syndrome and risk of chronic kidney disease (CKD) is not clear. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: The study cohort was composed of 10,685 healthy men without CKD, hypertension, or diabetes who participated in a health-checkup program at a large work site. PREDICTOR: Metabolic syndrome. OUTCOMES & MEASUREMENTS: CKD was defined as an estimated glomerular filtration rate (GFR) less than 60 mL/min/1.73 m(2). A standard Cox proportional hazards model and a time-dependent Cox model were used to calculate adjusted hazard ratios (HRs) in the CKD model. RESULTS: During 40,616.8 person-years of follow-up, 291 incident cases of CKD developed; 787 patients (7.4%) had metabolic syndrome at baseline and 1,444 (14.4%) developed incident metabolic syndrome during follow-up. After adjustment for age, baseline GFR, gamma-glutamyltransferase level, and uric acid level, metabolic syndrome at baseline was associated with a significantly increased risk of CKD (HR, 1.99; 95% confidence interval, 1.46 to 2.73). Metabolic syndrome over time as a time-dependent variable also predicted the development of CKD (HR, 1.83; [corrected] 95% confidence interval, 1.34 to 2.49) [corrected] The relationship between metabolic syndrome and incident CKD remained significant, even after further adjustment for the homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein level, current smoking, alcohol consumption, or regular exercise. In addition, there were graded relationships between number of metabolic syndrome traits or quintile of homeostasis model assessment of insulin resistance over time as a time-dependent variable and risk of CKD. Both increased triglyceride and low high-density lipoprotein cholesterol levels among metabolic syndrome traits were associated with significantly increased risk of CKD. These results were effectively unchanged, even after additional adjustment for incident hypertension and incident diabetes. LIMITATIONS: Estimated GFR was used instead of a directly measured GFR to define CKD. CONCLUSION: Metabolic syndrome is an independent risk factor for the development of CKD in Korean men without hypertension or diabetes, even with changes in status of metabolic syndrome over time.