Groupe de recherche PRIMUS, Department of Family Medicine, University of Sherbrooke, 3001 12e Ave N, Sherbrooke, QC J1H 5N4, Canada; Research Center on Aging, 1036 Rue Belvédère S, Sherbrooke, QC J1H 4C4, Canada.
Groupe de recherche PRIMUS, Department of Family Medicine, University of Sherbrooke, 3001 12e Ave N, Sherbrooke, QC J1H 5N4, Canada.
Mech Ageing Dev. 2020 Dec;192:111344. doi: 10.1016/j.mad.2020.111344. Epub 2020 Sep 16.
Are diseases caused by aging? What are the mechanisms of aging? Do all species age? These hotly debated questions revolve around a unitary definition of aging. Because we use the word "aging" so frequently, both colloquially and scientifically, we rarely pause to consider whether this word maps to an underlying biological phenomenon, or whether it is simply a grab-bag of diverse phenomena linked more by our mental associations than by any underlying biology. Here, we consider how the presence of the colloquial word "aging" generates a cognitive bias towards supposing there is a unitary biological phenomenon. We ask what kind of evidence would support or refute that idea, and subsequently show clear evidence at multiple levels that aging is not a unitary phenomenon. In particular, the known aging pathways lead to heterogeneous outputs, not a single coordinated phenomenon. From levels ranging from cellular/molecular to clinical to demographic to evolutionary, we show how the supposition that aging is a unitary phenomenon can mislead and distract us from asking the best questions. For major sub-disciplines of aging biology, we show how going beyond the notion of unitary aging can hone the paradigm and help advance the pace of discovery.
疾病是由衰老引起的吗？衰老的机制是什么？所有物种都会衰老吗？这些备受争议的问题都围绕着衰老的单一定义展开。由于我们在日常用语和科学中频繁使用“衰老”一词，因此很少会停下来思考这个词是否映射到一个潜在的生物学现象上，或者它是否仅仅是一系列不同现象的统称，这些现象更多地与我们的心理联想有关，而与任何潜在的生物学联系不大。在这里，我们考虑了“衰老”这个常用词的存在如何产生一种认知偏见，使人们倾向于假设存在一种单一的生物学现象。我们询问什么样的证据可以支持或反驳这个观点，随后在多个层面上展示了明确的证据，表明衰老不是一种单一的现象。特别是，已知的衰老途径会导致异质的结果，而不是单一的协调现象。从细胞/分子到临床到人口统计再到进化的各个层面，我们展示了衰老作为一种单一现象的假设如何会误导我们，并使我们无法提出最佳问题。对于衰老生物学的主要分支学科，我们展示了超越单一衰老概念如何能使范式更加精确，并有助于加快发现的步伐。
