Blackmore Daniel G, Waters Michael J
Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
Front Neurosci. 2023 Mar 7;17:1082449. doi: 10.3389/fnins.2023.1082449. eCollection 2023.
Advanced age is typically associated with a decrease in cognitive function including impairment in the formation and retention of new memories. The hippocampus is critical for learning and memory, especially spatial learning, and is particularly affected by ageing. With advanced age, multiple neural components can be detrimentally affected including a reduction in the number of neural stem and precursor cells, a decrease in the formation of adult born neurons (neurogenesis), and deficits in neural circuitry, all of which ultimately contribute to impaired cognitive function. Importantly, physical exercise has been shown to ameliorate many of these impairments and is able to improve learning and memory. Relevantly, growth hormone (GH) is an important protein hormone that decreases with ageing and increases following physical exercise. Originally described due to its role in longitudinal growth, GH has now been identified to play several additional key roles, especially in relation to the brain. Indeed, the regular decrease in GH levels following puberty is one of the most well documented components of neuroendocrine ageing. Growth hormone deficiency (GHD) has been described to have adverse effects on brain function, which can be ameliorated GH replacement therapy. Physical exercise has been shown to increase circulating GH levels. Furthermore, we recently demonstrated the increase in exercise-mediated GH is critical for improved cognitive function in the aged mouse. Here we examine the multiple roles that GH plays, particularly in the aged brain and following trauma, irradiation and stroke, and how increasing GH levels can ameliorate deficits in cognition.
高龄通常与认知功能下降有关，包括新记忆形成和保留方面的损害。海马体对学习和记忆至关重要，尤其是空间学习，并且特别容易受到衰老的影响。随着年龄的增长，多个神经成分会受到不利影响，包括神经干细胞和前体细胞数量减少、成年后生成神经元（神经发生）减少以及神经回路缺陷，所有这些最终都会导致认知功能受损。重要的是，体育锻炼已被证明可以改善其中许多损害，并能够改善学习和记忆。与此相关的是，生长激素（GH）是一种重要的蛋白质激素，会随着年龄增长而减少，而在体育锻炼后会增加。生长激素最初因其在纵向生长中的作用而被描述，现在已被确定还发挥着其他几个关键作用，尤其是与大脑有关的作用。事实上，青春期后生长激素水平的定期下降是神经内分泌衰老中记录最充分的组成部分之一。生长激素缺乏症（GHD）已被描述对脑功能有不利影响，而生长激素替代疗法可以改善这种影响。体育锻炼已被证明可以提高循环中的生长激素水平。此外，我们最近证明运动介导的生长激素增加对改善老年小鼠的认知功能至关重要。在这里，我们研究生长激素所起的多种作用，特别是在老年大脑以及创伤、辐射和中风后的作用，以及提高生长激素水平如何改善认知缺陷。
