title: Higher circulating levels of IGF-1 are associated with longer leukocyte telomere length in healthy subjects.
abstract: Mutations that inhibit the insulin-like growth factor-1 (IGF-1) extend the lifespan of worms, flies and mice. However, it appears that relatively low circulating levels of IGF-1 in humans are associated with aging-related diseases and diminished longevity. As leukocyte telomere length (LTL) is ostensibly a biomarker of human aging, we examined the relationship between LTL and blood IGF-1 in a healthy cohort. Our sample comprised 476 healthy, unrelated Caucasians (208 men and 268 women), aged 16-104 years, living in the West Coast of Southern Italy. We measured LTL by Southern blots and IGF-1 by enzyme-linked immunoassay. Both IGF-1 and LTL diminished with age (IGF-1, r=-0.601, P<0.001; LTL, r=-0.706, P<0.001). Age-adjusted LTL was positively associated with IGF-1 level throughout the age range of the cohort (r=0.270, P<0.001). IGF-1 accounted for about 10% of the inter-individual variation in LTL over and above the effect of age. Our findings suggest that both circulating IGF-1 and LTL are indices of healthy aging in humans. Further research will be necessary to establish whether LTL will ultimately be used in clinical settings as an index of healthy aging.
authors.affiliation: Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Piazza Miraglia 2, 80138 Naples, Italy.
authors.forename: Michelangela
authors.initials: M
authors.lastname: Barbieri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Paolisso
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kimura
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Gardner
authors.forename: Virginia
authors.initials: V
authors.lastname: Boccardi
authors.forename: Michela
authors.initials: M
authors.lastname: Papa
authors.forename: Jacob V
authors.initials: JV
authors.lastname: Hjelmborg
authors.forename: Kaare
authors.initials: K
authors.lastname: Christensen
authors.forename: Michael
authors.initials: M
authors.lastname: Brimacombe
authors.forename: Tim S
authors.initials: TS
authors.lastname: Nawrot
authors.forename: Jan A
authors.initials: JA
authors.lastname: Staessen
authors.forename: Michael N
authors.initials: MN
authors.lastname: Pollak
authors.forename: Abraham
authors.initials: A
authors.lastname: Aviv
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D006706:Homeostasis; D006801:Humans; D007333:Insulin Resistance; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007962:Leukocytes / Q000648:ultrastructure*; D008136:Longevity / Q000502:physiology; D008297:Male; D008875:Middle Aged; D012737:Sex Factors; D016615:Telomere / Q000648:ultrastructure*
chemical_list: D007334:Insulin-Like Growth Factor I