随着公众舆论倾向于接受和随之而来的合法化,大麻的消费正在上升。具体来说,老年人是大麻使用量增加最快的人口之一,但旨在了解大麻对老年大脑影响的研究仍然很少。衰老的特征是许多大脑变化会慢慢改变认知能力。在衰老过程中受到很大影响的一个过程是轴突髓鞘形成。髓鞘的缓慢降解和损失(即,脱髓鞘)随着年龄的增长,大脑中的脱髓鞘已被证明与认知能力下降有关,此外,是衰老中经历的许多神经系统疾病的共同特征。目前还不知道是什么原因导致这种依赖年龄的退化,但这可能是由于许多混杂因素(即,炎症加剧,血流量减少,细胞衰老)影响许多负责维持整体稳态和髓磷脂完整性的细胞。重要的是,使用非人灵长类动物和啮齿类动物的动物研究也揭示了随着年龄的增长脱髓鞘,为研究人员提供了一个可靠的模型来尝试和理解细胞机制。在啮齿动物中,大麻最近被证明可以调节髓鞘形成过程。此外,研究大麻对小胶质细胞的直接调节作用,星形胶质细胞和少突胶质细胞谱系细胞暗示了潜在的机制,以防止这些细胞在衰老过程中导致脱髓鞘的一些更具破坏性的活动。然而,目前缺乏关于大麻如何影响老年大脑髓鞘形成的研究。因此,这篇综述将探索迄今为止积累的证据,以显示大麻如何影响髓鞘形成,并将推断这些知识对老年人大脑可能意味着什么。
Consumption of cannabis is on the rise as public opinion trends toward acceptance and its consequent legalization. Specifically, the senior population is one of the demographics increasing their use of cannabis the fastest, but research aimed at understanding cannabis\' impact on the aged brain is still scarce. Aging is characterized by many brain changes that slowly alter cognitive ability. One process that is greatly impacted during aging is axonal
myelination. The slow degradation and loss of myelin (i.e., demyelination) in the brain with age has been shown to associate with cognitive decline and, furthermore, is a common characteristic of numerous neurological diseases experienced in aging. It is currently not known what causes this age-dependent degradation, but it is likely due to numerous confounding factors (i.e., heightened inflammation, reduced blood flow, cellular senescence) that impact the many cells responsible for maintaining overall homeostasis and myelin integrity. Importantly, animal studies using non-human primates and rodents have also revealed demyelination with age, providing a reliable model for researchers to try and understand the cellular mechanisms at play. In rodents, cannabis was recently shown to modulate the
myelination process. Furthermore, studies looking at the direct modulatory impact cannabis has on microglia, astrocytes and oligodendrocyte lineage cells hint at potential mechanisms to prevent some of the more damaging activities performed by these cells that contribute to demyelination in aging. However, research focusing on how cannabis impacts
myelination in the aged brain is lacking. Therefore, this
review will explore the evidence thus far accumulated to show how cannabis impacts
myelination and will extrapolate what this knowledge may mean for the aged brain.