Dingledine Ray, Varvel Nicholas H, Dudek F Edward
Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, 30322, USA,
Adv Exp Med Biol. 2014;813:109-22. doi: 10.1007/978-94-017-8914-1_9.
The effect of seizures on neuronal death and the role of seizure-induced neuronal death in acquired epileptogenesis have been debated for decades. Isolated brief seizures probably do not kill neurons; however, severe and repetitive seizures (i.e., status epilepticus) certainly do. Because status epilepticus both kills neurons and also leads to chronic epilepsy, neuronal death has been proposed to be an integral part of acquired epileptogenesis. Several studies, particularly in the immature brain, have suggested that neuronal death is not necessary for acquired epileptogenesis; however, the lack of neuronal death is difficult if not impossible to prove, and more recent studies have challenged this concept. Novel mechanisms of cell death, beyond the traditional concepts of necrosis and apoptosis, include autophagy, phagoptosis, necroptosis, and pyroptosis. The traditional proposal for why neuronal death may be necessary for epileptogenesis is based on the recapitulation of development hypothesis, where a loss of synaptic input from the dying neurons is considered a critical signal to induce axonal sprouting and synaptic-circuit reorganization. We propose a second hypothesis - the neuronal death pathway hypothesis, which states that the biochemical pathways causing programmed neurodegeneration, rather than neuronal death per se, are responsible for or contribute to epileptogenesis. The reprogramming of neuronal death pathways - if true - is proposed to derive from necroptosis or pyroptosis. The proposed new hypothesis may inform on why neuronal death seems closely linked to epileptogenesis, but may not always be.
癫痫发作对神经元死亡的影响以及癫痫发作诱导的神经元死亡在获得性癫痫发生中的作用已经争论了数十年。孤立的短暂癫痫发作可能不会导致神经元死亡;然而,严重且反复的癫痫发作(即癫痫持续状态)肯定会。由于癫痫持续状态既会导致神经元死亡,又会引发慢性癫痫,因此有人提出神经元死亡是获得性癫痫发生的一个重要组成部分。多项研究,尤其是在未成熟大脑中的研究表明,神经元死亡对于获得性癫痫发生并非必要;然而,即使并非不可能,缺乏神经元死亡也很难证明,而且最近的研究对这一概念提出了挑战。除了传统的坏死和凋亡概念之外,新的细胞死亡机制还包括自噬、吞噬性细胞死亡、坏死性凋亡和炎性程序性坏死。关于神经元死亡为何可能是癫痫发生所必需的传统观点基于发育假说的重演,即垂死神经元的突触输入丧失被认为是诱导轴突发芽和突触回路重组的关键信号。我们提出了第二个假说——神经元死亡途径假说,该假说认为导致程序性神经退行性变的生化途径,而非神经元死亡本身,是癫痫发生的原因或促成因素。如果属实,神经元死亡途径的重编程被认为源自坏死性凋亡或炎性程序性坏死。所提出的新假说或许可以解释为何神经元死亡似乎与癫痫发生密切相关,但并非总是如此。