Published in:
Open Access 01-12-2009 | Research article
A polymorphic variant of the insulin-like growth factor 1 (IGF-1) receptor correlates with male longevity in the Italian population: a genetic study and evaluation of circulating IGF-1 from the "Treviso Longeva (TRELONG)" study
Published in: BMC Geriatrics | Issue 1/2009
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Background
An attenuation of the insulin-like growth factor 1 (IGF-1) signaling has been associated with elongation of the lifespan in simple metazoan organisms and in rodents. In humans, IGF-1 level has an age-related modulation with a lower concentration in the elderly, depending on hormonal and genetic factors affecting the IGF-1 receptor gene (IGF-1R).
Methods
In an elderly population from North-eastern Italy (n = 668 subjects, age range 70–106 years) we investigated the IGF-1R polymorphism G3174A (rs2229765) and the plasma concentration of free IGF-1. Frequency distributions were compared using χ2-test "Goodness of Fit" test, and means were compared by one-way analysis of variance (ANOVA); multiple regression analysis was performed using JMP7 for SAS software (SAS Institute, USA). The limit of significance for genetic and biochemical comparison was set at α = 0.05.
Results
Males showed an age-related increase in the A-allele of rs2229765 and a change in the plasma level of IGF-1, which dropped significantly after 85 years of age (85+ group). In the male 85+ group, A/A homozygous subjects had the lowest plasma IGF-1 level. We found no clear correlation between rs2229765 genotype and IGF-1 in the females.
Conclusion
These findings confirm the importance of the rs2229765 minor allele as a genetic predisposing factor for longevity in Italy where a sex-specific pattern for IGF-1 attenuation with ageing was found.