脑铁代谢与脑出血后脑损伤

脑出血后血肿周围脑组织损伤的机制十分复杂。最近研究显示,脑出血后铁离子和铁代谢蛋白的代谢异常是导致脑出血后脑损伤的原因之一。本文对目前脑铁分布、功能和脑内铁转运机制的认识,脑出血后异常增高的铁离子和铁代谢蛋白导致脑损伤的作用机制,以及异常脑铁代谢的磁共振成像检查和铁螯合剂的实验研究作了简要综述。     

缺氧诱导因子影响脑铁代谢调控神经系统铁超载的机制研究进展

铁超载作为许多神经系统疾病的病理性特征, 可引起氧化应激反应, 导致神经细胞铁代谢异常。缺氧诱导因子(HIF)可通过调控脑铁的摄取、储存、排出和胞内调节等过程参与脑铁代谢, 抑制脑铁超载有望成为神经系统疾病治疗的新靶点。本文现围绕HIF调控脑铁代谢的生理/病理机制综述如下, 以期为相关神经系统疾病的治疗提供新的思路和方法。     

脑铁代谢失衡与迟发性运动障碍

对脑铁代谢的基本过程及脑铁代谢失衡与迟发性运动障碍的关系进行综述。     

脑铁离子转运途径及铁转运相关蛋白的研究进展

既往认为铁离子对人体有益,对脑发育和功能的维持具有重要作用,但越来越多的研究显示过量的铁对大脑具有神经毒性作用,但目前缺乏有效的防治途径。因此有必要探讨铁离子在脑组织中的转运途径及转运相关蛋白,为防治脑出血、颅脑损伤,以及帕金森综合征、阿尔茨海默病造成铁离子累积所致脑损害提供可能的新靶点。     

脑内铁代谢与神经退行性疾病

铁的正常代谢是大脑发挥正常功能的必要因素。近年研究发现,脑内铁的代谢紊乱在阿尔茨海默病、帕金森病等神经退行性疾病的发生发展中起重要作用。本文对脑内铁正常和异常代谢调节情况及其与神经退行性疾病的关系做一综述。     

铁代谢异常与中枢神经系统疾病

由于血脑屏障的存在,脑铁代谢与外周器官不同.铁在脑内代谢的异常可致脑铁沉积或脑内铁缺乏,导致细胞生理功能障碍,引起神经细胞的死亡.目前已经发现阿尔茨海默病、帕金森病、癫、不宁腿综合征的发病机制及疾病的发展与脑铁代谢异常有关.     

脑梗塞后脑代谢及高糖对脑代谢影响的研究

目的 探测脑梗塞后梗塞区及对照区域的代谢变化并探讨高糖对梗塞区域代谢的影响，为脑梗塞的临床治疗提供理论依据。方法 雄性SD大鼠左侧颈内动脉插线法制作脑梗塞模型。用磁共振定域^1H—MRS技术，在同一活体上分别连续检测梗塞区及对照区域代谢变化。结果 脑梗塞后梗塞区NAA、Cho、Pcr／Cr强度均低于对照区，并出现明显的Lac信号。NAA在脑梗塞急性期明显降低。加用高糖1～2h内，所选区域NAA、Cho、Pcr／Cr均有小幅回升，随后又渐趋下降；原有乳酸信号成倍增加(2．4倍)。结论 (1)NAA的变化可反映神经元的功能状况，可望作为MRS早期诊断脑梗死的有效指标。(2)Lac峰的出现是脑梗死早期的敏感指标，其含量变化可直接反映局部病理代谢状况。(3)NAA和Cho的降低证明脑梗塞后即发生细胞膜结构、膜功能及膜间连接损伤；(4)高糖可加剧脑梗塞区的病理代谢导致Lac大量积聚；(5)采用MRS定域波谱技术可更精确、更客观地连续检测活体动物大脑各区域代谢变化。     

铁代谢在创伤性颅脑损伤中的研究进展

创伤性颅脑损伤(traumatic brain injury,TBI)是一类由多种因素导致的颅脑损伤性疾病,可引起一系列复杂的病理生理过程.缺乏早期干预靶点是TBI预后不良的重要因素.另外,TBI不良预后与损伤脑组织铁代谢紊乱密切相关,铁代谢调节干预,尤其是铁螯合剂,在TBI中显示出巨大治疗潜力.本文将对铁代谢与TBI...     

MRI检测帕金森病脑铁含量的研究进展

近来研究表明,帕金森病有脑铁代谢紊乱、脑铁含量增多。由于脑铁使MRI中TW12信号降低,可根据TW12信号强度定量评估脑内各部铁含量的变化。因此,运用MRI不同序列可能为PD发病机理及定量诊断提供了一种有参考价值的无创的新的评估方法。     

Wilson病患者的铁代谢相关指标研究

目的:研究Wilson病(WD)患者的血清铁代谢相关指标水平.方法:选取未接受过正规驱铜治疗的WD患者103例(WD组),WD组再依据MRI异常分为3个亚组:WD-MRI无异常组、WD-MRI长T2组和WD-MRI短T2组.另选取健康志愿者25名(正常对照组)和乙肝患者18例(乙肝对照组)为研究对象.WD组患者于入院时进行血清铜蓝蛋白以及血清铁代谢指标测定;正常对照组及乙肝对照组均检测铁代谢指标.结果:WD各亚组高铁铁蛋白水平与正常对照组比均显著增高,差异有统计学意义(P<0.05);与乙肝对照组比较则显著降低(P<0.01).WD组转铁蛋白明显降低,与正常对照组和乙肝对照组比较,均差异有显著统计学意义(均P<0.01).WD各亚组的人转铁蛋白受体与乙肝对照组比较,差异有显著统计学意义(P<0.01);乙肝对照组与正常对照组比较,差异有显著统计学意义(P<0.01).结论:WD患者存在铁代谢异常,但不同于乙肝对照组的人转铁蛋白受体高表达,可能是转铁蛋白的低调节所致.     

Systemic iron metabolism: a review and implications for brain iron metabolism

Mammalian cells and organisms coordinate to regulate expression of numerous proteins involved in the uptake, sequestration, and export of iron. When cells in the systemic circulation are depleted of iron, they increase synthesis of the transferrin receptor and decrease synthesis of the iron sequestration protein, ferritin. In iron-depleted animals, expression of duodenal iron transporters markedly increases and intestinal iron uptake increases accordingly. The major proteins of iron metabolism in the systemic circulation are also expressed in the central nervous system. However, the mechanisms by which iron is transported and distributed throughout the central nervous system are not well understood. Iron accumulation in specific regions of the brain is observed in several neurodegenerative diseases. It is likely that misregulation of iron metabolism is important in the pathophysiology of several human neurodegenerative diseases.     

Hallervorden-Spatz syndrome and brain iron metabolism.

Aberrant iron metabolism in the brain is typified by Hallervorden-Spatz syndrome. In this disorder, large amounts of iron are deposited in the globus pallidus and the pars reticulata of the substantia nigra. It is characterized by extrapyramidal dysfunction, as demonstrated by dystonia, rigidity, and choreoathetosis; onset during the first two decades of life; and progression of signs and symptoms. Corroborative findings include corticospinal tract involvement, ie, spasticity and extensor toe signs, progressive intellectual impairment, retinitis pigmentosa and optic atrophy (usually associated visual evoked response and electroretinogram abnormalities), seizures, familial occurrence, hypointense areas in the basal ganglia on magnetic resonance imaging scans (particularly in the substantia nigra), abnormal cytosomes in circulating lymphocytes, and sea-blue histiocytes in bone marrow. Iron function in normal brain metabolism is manifold, but high concentrations of iron in the basal ganglia area may signal a unique relationship. Data support the likelihood that iron plays a role in the modulation of dopamine binding to postsynaptic receptors. In addition, transferrin receptors and iron are also concentrated in oligodendrocytes in normal brain and, thus, may have a function in myelination. A role of iron also seems likely in oxidation and peroxidation reactions involving membranes and DNA, a capability that becomes uncontrolled when protective biologic mechanisms become inadequate.     

Rethinking the role of ceruloplasmin in brain iron metabolism

For more than three decades, it has been widely accepted that ceruloplasmin plays an important role in iron efflux from mammalian cells, including brain cells, via the activity of ferroxidase. However, in light of recent findings, this view might not be completely accurate and the role of ceruloplasmin in brain iron metabolism may need to be re-evaluated. Based on recent studies, we propose in this article that the role of ceruloplasmin in iron uptake by brain neuronal cells might be more important than its role in iron release from the cells. A possible explanation of why the absence of ceruloplasmin induces excessive iron accumulation in neurons in aceruloplasminemia (ceruloplasmin gene mutations) was also discussed.     

大鼠脑室出血后脑铁代谢与脑积水发生关系的研究

目的 观察脑室出血后铁离子和铁蛋白的动态变化,及去铁敏治疗前后慢性脑积水的发生率.方法 SD雄性大鼠170只,随机分为5组:正常对照组、假性脑室出血组、脑室出血组、侧脑室注铁离子组及脑室出血加去铁敏组.以前肉后0.4 mm冠状面的侧脑室宽度评价脑积水的发生率,以亚铁嗪法测量大鼠脑脊液铁离子含量,以ELISA试剂盒测量脑组织铁蛋白含量.结果 正常对照组、假性脑室出血组无脑积水发生,脑室出血组、侧脑室注铁离子组、脑室出血加去铁敏组28 d时脑积水发生率分别为80％、73％、20％,脑室出血加去铁敏组脑积水发生率显著低于脑室出血组和侧脑室注铁离子组(P＜0.01).脑脊液中铁离子含量和脑组织中铁蛋白在脑室出血组和侧脑室注铁离子组中各个时相点均显著高于假性脑室出血组(P＜0.01);脑室出血加去铁敏组铁离子含量在各个时相点,及铁蛋白在7、28d时均显著低于脑室出血组(P＜0.01).结论 大鼠脑室出血后脑脊液和脑组织铁含量明显升高,去铁敏可降低脑脊液中铁离子和脑组织中铁蛋白含量,降低脑积水的发生率.     

Neurotoxic effects of iron overload under high glucose concentration

Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be associated with oxidative stress and the NF-E2-related factor 2 （Nrf2）/ARE signaling pathway. As an in vitro cellular model of diabetic peripheral neuropathy, PC12 cells ex- posed to high glucose concentration were used in this study. PC12 cells were cultured with ferric ammonium citrate at different concentrations to create iron overload. PC12 cells cultured in ferric ammonium citrate under high glucose concentration had significantly low cell viability, a high rate of apoptosis, and elevated reactive oxygen species and malondialdehyde levels. These changes were dependent on ferric ammonium citrate concentration. Nrf2 mRNA and protein expression in the ferric ammonium citrate groups were inhibited markedly in a dose-dependent manner. All changes could be inhibited by addition of deferoxamine. These results indicate that iron overload aggravates oxidative stress injury in neural cells under high glucose concentration and that the Nrf2/ARE sigfnaling pathway might play an important role in this process.