title: Evidence that the gene encoding insulin degrading enzyme influences human lifespan.
abstract: Studies in model organisms have demonstrated that components of insulin and insulin-like signaling pathways are involved in the regulation of lifespan but the relevance of those findings to humans has remained obscure. Here we provide evidence suggesting that variants of the gene encoding insulin-degrading enzyme (IDE) may be influencing human lifespan. We have employed a variety of models and diverse samples that reproducibly indicate the relative change in IDE genotype frequency across the age spectrum as well as allow the detection of association with age-at-death. A tenable molecular basis of this is suggested by the observation of genetic association with both fasting plasma insulin levels and IDE mRNA expression. Across populations the emergent genetic model is indicative of over-dominance, where heterozygotes of critical markers have increased IDE mRNA expression and insulin levels, and this is reflected in diminished heterozygosity at advanced age. A critical and replicating feature of this study is that change in IDE genotype frequency with advancing age appears to be occurring only in men, and this is supported in that insulin levels are only associated with IDE in men. Results suggest a relationship between a gene that is intimately involved in insulin metabolism and the determination of lifespan in humans, but over-dominance and gender specificity will be important parameters to consider clarifying the biological importance of these findings.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mun-Gwan
authors.initials: MG
authors.lastname: Hong
authors.forename: Chandra
authors.initials: C
authors.lastname: Reynolds
authors.forename: Margaret
authors.initials: M
authors.lastname: Gatz
authors.forename: Boo
authors.initials: B
authors.lastname: Johansson
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Palmer
authors.forename: Harvest F
authors.initials: HF
authors.lastname: Gu
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.forename: Patrick G
authors.initials: PG
authors.lastname: Kehoe
authors.forename: Ulf
authors.initials: U
authors.lastname: de Faire
authors.forename: Nancy L
authors.initials: NL
authors.lastname: Pedersen
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Prince
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D005260:Female; D015870:Gene Expression; D005838:Genotype; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007339:Insulysin / Q000235:genetics / Q000502:physiology*; D015810:Linkage Disequilibrium; D008136:Longevity / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D007328:Insulin; D012333:RNA, Messenger; D007339:Insulysin