A common arginine to proline polymorphism is harboured at codon 72 of the human p53 gene. In this investigation, we found that fibroblasts and lymphocytes isolated from arginine allele homozygote centenarians and sexagenarians (Arg þ ) undergo an oxidative-stress-induced apoptosis at a higher extent than cells obtained from proline allele carriers (Pro þ ). At variance, the difference in apoptosis susceptibility between Arg þ and Pro þ is not significant when cells from 30-year-old people are studied. Further, we found that Arg þ and Pro þ cells from centenarians differ in the constitutive levels of p53 protein and p53/MDM2 complex, as well as in the levels of oxidative stress-induced p53/Bcl-xL complex and mitochondria-localised p53. Consistently, all these differences are less evident in cells from 30-year-old people. Finally, we investigated the in vivo functional relevance of the p53 codon 72 genotype in a group of old patients (66-99 years of age) affected by acute myocardial ischaemia, a clinical condition in which in vivo cell death occurs. We found that Arg þ patients show increased levels of Troponin I and CK-MB, two serum markers that correlate with the extent of the ischaemic damage in comparison to Pro þ patients. In conclusion, these data suggest that p53 codon 72 polymorphism contributes to a genetically determined variability in apoptotic susceptibility among old people, which has a potentially relevant role in the context of an age-related pathologic condition, such as myocardial ischaemia.

SummarySequence variations in a variety of pro-or anti-inflammatory cytokine genes have been found to influence successful aging and longevity. Because of the role played by the transforming growth factor β β β β 1 (TGF-β β β β 1) cytokine in inflammation and regulation of immune responses, the variability of the TGF-β β β β 1 gene may affect longevity by playing a role in inflamm-aging. Two polymorphisms, G/ A − − − − 800 and C/T − − − − 509 , located in the 5′ ′ ′ ′ region, and two missense polymorphisms, T/C 869 and G/C 915 which change (Leu > Pro) 10 and (Arg > Pro) 25 , respectively, located in the signal peptide, were analysed in 419 subjects from Northern and Central Italy, including 172 centenarians and 247 younger controls. In addition, the effects of the TGF-β β β β 1 genetic variability on plasma levels of the biologically active form (naturally processed) of this cytokine were studied in 143 randomly selected subjects, including 73 centenarians. Significant differences were found at the +915 site as far as the C allele and GC genotype were concerned, both of them being lower in centenarians than in young controls ( P = 0.034 and 0.028, respectively), but none of the other tested genetic variants was significantly different between centenarians and controls. Moreover, a particular haplotype combination (G − − − − 800 /C − − − − 509 /C 869 /C 915 ) was notably lower in centenarians than in younger individuals ( P = 0.007). Finally, active TGF-β β β β 1 plasma levels were significantly increased in the elderly group, but no relationship with TGF-β β β β 1 genotypes was observed. These results suggest that, at least in this population, the variability of the TGF-β β β β 1 gene influences longevity and that the age-related increase in plasma levels of active TGF-β β β β 1 seems not to be genetically regulated.

To investigate the genetic contribution to familial similarity in longevity, we set up a novel experimental design where cousin-pairs born from siblings who were concordant or discordant for the longevity trait were analyzed. To check this design, two chromosomal regions already known to encompass longevity-related genes were examined: 6p21.3 (genes TNFa, TNFb, HSP70.1) and 11p15.5 (genes SIRT3, HRAS1, IGF2, INS, TH). Population pools of 1.6, 2.3 and 2.0 million inhabitants were screened, respectively, in Denmark, France and Italy to identify families matching the design requirements. A total of 234 trios composed by one centenarian, his/her child and a child of his/her concordant or discordant sib were collected. By using population-specific allele frequencies, we reconstructed haplotype phase and estimated the likelihood of Identical By Descent (IBD) haplotype sharing in cousin-pairs born from concordant and discordant siblings. In addition, we analyzed haplotype transmission from centenarians to offspring, and a statistically significant Transmission Ratio Distortion (TRD) was observed for both chromosomal regions in the discordant families (P ¼ 0.007 for 6p21.3 and P ¼ 0.015 for 11p15.5). In concordant families, a marginally significant TRD was observed at 6p21.3 only (P ¼ 0.06). Although no significant difference emerged between the two groups of cousin-pairs, our study gave new insights on the hindrances to recruiting a suitable sample to obtain significant IBD data on longevity-related chromosomal regions. This will allow to dimension future sampling campaigns to study-genetic basis of human longevity.

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