瘦素与骨代谢及肾性骨病

Relationship of leptin with bone metabolism and renal osteopathy

背景:瘦素是一种主要由脂肪组织分泌的激素,影响机体许多生理系统和代谢通路,并与许多疾病关系密切。目的:回顾与分析瘦素与骨代谢及肾性骨病的关系。资料来源:应用计算机检索Medline数据库1998-01/2004-12期间的相关文章,分别检索词为“leptin,bone”和“leptin,renal”,限定文章语言种类为English。资料选择:对资料进行初审,选取包括瘦素的基础或者临床研究文献,然后筛出明显不相关的文献,对余下的文献开始查找全文,进一步判断是否符合纳入标准,纳入标准:①基础研究。②与人类疾病具有相关性临床研究。资料提炼:共检索到474篇与瘦素相关的文章,根据实验研究的质量及与人类疾病的相关性引用31篇文章。包含有关瘦素概述的文章4篇,瘦素与骨代谢的研究25篇,2篇有关瘦素与肾性骨病的研究。资料综合:①瘦素影响分为两方面,即负性中枢作用和正性外周作用,而两方面作用的最终结果可能取决于血清瘦素的水平、血脑屏障对瘦素的转运能力等。②血清瘦素水平较低时,外周作用甚微,此时以中枢负性效应为主,导致骨质丢失、骨密度降低。③许多肥胖患者血清瘦素明显升高并超过一定界限时,血脑屏障对瘦素的转运达到饱和,此时外周正性作用可能大于中枢负性作用,从而促进骨形成,而许多慢性肾衰或维持性血透伴高瘦素血症的患者可能也存在类似情况。结论:瘦素从多方面对骨代谢起重要的调节作用,但也有学者认为瘦素与骨密度不相关,提示瘦素对骨转换和骨密度无直接作用。总之,瘦素与骨转换、骨密度的相关性,为临床骨代谢相关疾病的防治提供了新的思路。

BACKGROUND:Leptin,one of hormones secreted from adipose tissues,has an effect on many physiological systems and metabolic pathways and is closely related to many diseases. OBJECTIVE:To review and analyze the relationship of leptin with bone metabolism and renal osteotrophy. DATA SOURCES:A computer-based search in Medline for related articles published between January 1998 and December 2004 was performed by using the 'leptin,bone″ and 'leptin,renal″,and the language was limited to English. STUDY SELECTION:After the first check-up,the articles about clinical or basic studies of leptin were selected,and then the obviously unrelated articles were excluded.The full texts of the rest articles were searched for to further judge whether they were accordant with the inclusion criteria:①basic studies,②clinical research relevant to human diseases. DATA EXTRACTION:Totally 474 articles were related to leptin,in which 31 were cited on the basis of the quality of experimental studies and these studies' relevance to human diseases,including 4 articles about the summary of leptin,25 about leptin and bone metabolism,and 2 about leptin and renal osteopathy. DATA SYNTHESIS:①The effect of leptin on bone metabolism included two sides:negative central effect and positive peripheral effect,and the ultimate outcome might lie on the level of leptin serum,the transport capacity of blood-brain barrier for leptin and so on.②The peripheral effect of leptin was mild,when its serum level was low,mainly substituted by negative central effect to induce the loss of bone matrix and decrease of bone mineral density(BMD).③The transport capacity of blood-brain barrier for leptin reached its saturation when the level of serum leptin increased and surpassed a certain threshold in many obese patients,and simultaneously the positive peripheral effect might be more than the negative central effect,thus to induce the formation of new bone,which might similarly exist in the patients with chronic renal failure or maintenance hemodialysis accompanied by high level of leptin. CONCLUSION:Leptin regulates bone metabolism from various aspects,but there are also some researchers consider that leptin has nothing to do with BMD and suggest that leptin has no direct effect on bone transition and BMD.Anyway,the relativity of leptin to bone transition and BMD has provided some new directions for the prevention and treatment of bone metabolism associated diseases.