Letra Liliana, Santana Isabel, Seiça Raquel
Serviço de Neurologia, Centro Hospitalar e Universitário de Coimbra, Portugal, Av. Bissaya Barreto - Praceta Prof Mota Pinto, 3000-075, Coimbra, Portugal,
Metab Brain Dis. 2014 Sep;29(3):563-8. doi: 10.1007/s11011-014-9501-z. Epub 2014 Feb 20.
Alzheimer's disease is the leading cause of dementia and the most prevalent neurodegenerative disease. It is an aging-related multi-factorial disorder and growing evidence support the contribution of metabolic factors to what was formerly thought to be a centrally mediated process. Obesity has already been recognized as an important player in the pathogenesis of this type of dementia, independently of insulin resistance or other vascular risk factors. Although the exact underlying mechanisms are still unknown, adipocyte dysfunction and concomitant alteration in adipocyte-derived protein secretion seem to be involved, since these adipocytokines can cross the blood-brain barrier and influence cognitive-related structures. Very few studies have assessed the role of adipocytokines dysfunction on cognitive impaired patients and yielded contradictory results. Interestingly, extensive research on the central effects of leptin in Alzheimer's disease-transgenic mice has demonstrated its capacity to enhance synaptic plasticity and strength, as well as to prevent beta-amyloid deposition and tau phosphorylation. In addition, adiponectin, the most abundant adipocytokine whose levels are inversely correlated to adiposity, has shown to be neuroprotective to hippocampal cells. Many other adipose-derived cytokines have mainly pro-inflammatory properties, being able to trigger and/or enhance central inflammatory cascades and also to influence the secretion of other adipocytokines involved in cognition. This paper pretends to review the existing evidence on the contribution of adipocytokines dysfunction to the increased risk of dementia associated with mid-life obesity, unraveling its insulin-independent effects on cognition.
阿尔茨海默病是痴呆的主要病因,也是最常见的神经退行性疾病。它是一种与衰老相关的多因素疾病,越来越多的证据支持代谢因素对以前被认为是中枢介导过程的影响。肥胖已被公认为是这类痴呆发病机制中的一个重要因素,与胰岛素抵抗或其他血管危险因素无关。尽管确切的潜在机制尚不清楚,但脂肪细胞功能障碍以及脂肪细胞衍生蛋白分泌的相应改变似乎与之有关,因为这些脂肪细胞因子可以穿过血脑屏障并影响与认知相关的结构。很少有研究评估脂肪细胞因子功能障碍对认知受损患者的作用,且结果相互矛盾。有趣的是,对阿尔茨海默病转基因小鼠中瘦素的中枢作用进行的广泛研究表明,它有能力增强突触可塑性和强度,以及预防β-淀粉样蛋白沉积和tau蛋白磷酸化。此外,脂联素是最丰富的脂肪细胞因子,其水平与肥胖程度呈负相关,已被证明对海马细胞具有神经保护作用。许多其他脂肪衍生的细胞因子主要具有促炎特性,能够触发和/或增强中枢炎症级联反应,还能影响参与认知的其他脂肪细胞因子的分泌。本文旨在综述关于脂肪细胞因子功能障碍对与中年肥胖相关的痴呆风险增加的影响的现有证据,揭示其对认知的胰岛素非依赖性作用。