Despite differences in presentation, age-related dementing diseases such as Alzheimer’s (AD), Parkinson’s (PD), and Huntington’s diseases (HD), and dementia with Lewy bodies (DLB) may share pathogenic processes. This review aims to systematically assemble and compare findings in various biochemical pathways across these four dementias.

PubMed and Google Scholar were screened for articles reporting on brain and biofluid measurements of metals and/or metabolites in AD, PD, HD, or DLB. Articles were assessed using specific a priori-defined inclusion and exclusion criteria. Of 284 papers identified, 198 met criteria for inclusion.

Although varying coverage levels of metals and metabolites across diseases and tissues made comparison of many analytes impossible, several common findings were identified: elevated glucose in both brain tissue and biofluids of AD, PD, and HD cases; increased iron and decreased copper in AD, PD and HD brain tissue; and decreased uric acid in biofluids of AD and PD cases. Other analytes were found to differ between diseases or were otherwise not covered across all conditions.

These findings indicate that disturbances in glucose and purine pathways may be common to AD, PD, and HD. However, standardisation of methodologies and better coverage in some areas – notably of DLB – are necessary to validate and extend these findings.

尽管表现不同，但与年龄相关的痴呆症，如阿尔茨海默病 (AD)、帕金森病 (PD) 和亨廷顿病 (HD) 以及路易体痴呆 (DLB) 可能具有共同的致病过程。本综述旨在系统地汇总和比较这四种痴呆的各种生化途径的发现。

PubMed 和 Google Scholar 筛选了关于 AD、PD、HD 或 DLB 中金属和/或代谢物的脑和生物流体测量的文章。文章使用特定的先验定义的纳入和排除标准进行评估。在确定的 284 篇论文中，198 篇符合纳入标准。

尽管不同疾病和组织中金属和代谢物的覆盖水平不同，无法对许多分析物进行比较，但还是确定了几个共同的发现：AD、PD 和 HD 病例的脑组织和生物体液中的葡萄糖升高；AD、PD 和 HD 脑组织中铁增加和铜减少；并降低 AD 和 PD 病例生物体液中的尿酸。发现其他分析物在疾病之间存在差异，或者未涵盖所有条件。

这些发现表明葡萄糖和嘌呤通路的紊乱可能对 AD、PD 和 HD 很常见。然而，方法的标准化和在某些领域（尤其是 DLB）的更好覆盖对于验证和扩展这些发现是必要的。