Search

In this paper, we review data of recent literature on the distribution in centenarians of candidate germ-line polymorphisms that likely affect the individual chance to reach the extreme limit of human life. On the basis of previous observations on the immunology, endocrinology and cellular biology of centenarians we focused on genes that regulate immune responses and inflammation (IL-6, IL-1 cluster, IL-10), genes involved in the insulin/IGF-I signalling pathway and genes that counteract oxidative stress (PON1). On the whole, data indicate that polymorphisms of these genes likely contribute to human longevity, in accord with observations emerging from a variety of animal models, and suggest that a common core of master genes and metabolic pathways are responsible for aging and longevity across animal species. Moreover, in the concern of our plan to discover new genetic factors related to longevity, we explored the possibility to by-pass the need of an a-priori choice of candidate genes, extending the search to genes and genomic regions of still unknown function. Alu sequences may be considered as good markers of highly variable and potentially unstable loci in functionally important genomic regions. We extensively screened Alu-rich genomic sites and found a new genomic region associated with longevity.

Background: Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) are key mediators of inflammation and their increased plasma levels are associated with acute coronary syndrome (ACS). Polymorphisms in the promoter region of IL-6 (-174 G>C) and TNF-α(-308 G>A) demonstrated to affect gene expression were analyzed to test their predictive power for cardiovascular death over one year follow-up in elderly male ACS patients. Methods: We assessed the IL-6 -174 G>C polymorphism and TNF-α -308 G>A polymorphism in 139 consecutive elderly male patients affected by an ACS, such as ST-Elevation (STEMI), No ST-Elevation (NSTEMI) Myocardial Infarction and Unstable Angina. The presence of well known risk factors for Coronary Heart Diseases (CHD) were also assessed in all ACS patients. Survival rate was assessed after one year follow-up. Results: We found that IL-6 -174 G>C polymorphism is an independent predictor of cardiovascular death after an ACS in male patients. In particular ACS patients carrying the IL-6 -174 C- (GG) genotypes showed a marked increase in one year follow-up mortality rate (HR=3.89, 95% CI 1.71-8.86, p=0.001). Moreover CRP serum levels ≥5.5 mg/dl (HR= 3.79, 95% CI 1.71-8.42, p=0.001), a history of CHD (HR=2.96, 95% CI 1.22-7.20, p=0.016) and the absence of statins treatment (HR=3.27, 95% CI 1.17-9.18, p=0.021), significantly increased one year risk of death in male ACS patients. Conclusions: These data suggest that IL-6 -174 G>C polymorphism can be added to other clinical markers in order to identify a subgroup of elderly ACS male patients at higher risk of death. © 2005 Elsevier Ireland Ltd. All rights reserved

The (A/G)-308 polymorphism of the tumor necrosis factor alpha gene (TNF) is associated with age-related diseases, but its influence on longevity is controversial. We genotyped for this polymorphism 747 Italian volunteers (401 women and 346 men, age 19-110 years). By applying a genetic-demographic (GD) approach we found that, in men, the survival function of allele A carriers is lower than that of noncarriers at all the ages (p =.044). After defining (by exploiting again demographic information) three age classes, we found that the frequency of men carrying the A allele decreases with age (p =.019), thus confirming the GD analysis results. The same analyses gave negative results in women. Therefore, allele A has a detrimental effect on life expectancy, and this effect is specific to men. A haplotype analysis carried out in men by screening the TNFa, TNFc, and TNFe microsatellite polymorphisms (spanning about 20 kb) confirmed the association of the TNF region with life expectancy.

Udgivelsesdato: 2008-Feb 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 TNFalpha, TNFbeta, 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=0.007 for 6p21.3 and P=0.015 for 11p15.5). In concordant families, a marginally significant TRD was observed at 6p21.3 only (P=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.European Journal of Human Genetics (2008) 16, 236-242; doi:10.1038/sj.ejhg.5201950; published online 7 November 2007.

The uneven distribution of Alu repetitive elements in the human genome is related to specific functional properties of genomic regions. We report the identification of a locus associated with human longevity in one of the chromosomal regions with the highest density of Alu elements, in 1p35. The locus, corresponding to a (TG)n microsatellite in the YTHDF2 gene, was identified by characterizing an ‘‘anonymous’’ marker detectable through interAlu fingerprinting, which previously evidenced an increased homozygosity in centenarians. After genotyping 412 participants of different ages, including 137 centenarians, we confirmed the increased homozygosity in centenarians at this locus, and observed a concomitantly increased frequency of the most frequent allele and the corresponding homozygous genotype. Remarkably, the same genotype was associated with increased YTHDF2 messenger RNA levels in immortalized lymphocytes. Finally, YTHDF2 messenger RNA resulted to be mainly expressed in testis and placenta. The data suggest a possible role of this locus in human longevity.

The human forkhead box O1A (FOXO1A) gene belongs to the human forkhead gene family and acts downstream of the human insulin signalling pathway. In this study, polymorphisms of the Intron I of FOXO1A gene were studied in Italian healthy people and insulin resistant subjects. No significant association between the germ-line variability in the Intron I of FOXO1A and insulin resistance was observed. Interestingly, during the study, a new 39-bp sequence insertion polymorphism in Intron I of FOXO1A gene was described. The polymorphism was found to co-segregate in a co-dominant Mendelian fashion and to be present in an ethnically distinct population (Greeks). A BLAST search showed that the sequence shares 100% identity with a mtDNA (mitochondrial DNA) sequence coding for the ATP synthase 8 (ATPase8) and ATP synthase 6 (ATPase6) genes. Hence, FOXO1A Intron I is a polymorphic nuclear region involved in the exchange of DNA material between mitochondrial and genomic DNA, which is a well-established mechanism of evolutionary change in eukaryotes.

Cardiovascular diseases (CVD), such as myocardial infarction (MI), are major causes of disability and mortality in the elderly. The increasing burden of CVD in ageing industrialized populations requires intensive research in order to improve preventive and therapeutic strategies especially in old people and if possible slow the processes of cardiovascular disease generation and progression. Ageing is accompanied by an age-dependent up-regulation of the inflammatory response, due to chronic antigenic stress stimulation, which potentially triggers the onset of inflammatory diseases, especially CVD. However, the exact mechanisms are still poorly understood. Since CVD are caused by interactions between genetic and environmental factors, a possible approach to their prevention is to identify the potential genetic component of inflammatory cardiovascular risk factors, providing the basis for personalized lifestyle modification and improved pharmacological therapy. Some common gene polymorphisms associated with high production of inflammatory molecules have been associated with atherosclerosis. Therefore, controlling inflammation might play a protective role against CVD, especially in ageing. Although a large number of studies of pro- and anti-inflammatory gene variants in association with CVD and MI exists, the emerging data are quite conflicting and do not provide definitive evidence for a role of these polymorphisms in the pathogenesis of MI. In this paper we review the evidence for a possible role of genetic polymorphisms of the most important inflammatory cytokines (IL-6, TNF-α, IL-10) and immune receptors (CD14 receptor and TLR-4) in modulating the incidence or the prognosis of MI, with a special focus in ageing population.

Summary Adhesion of circulating cells to the arterial surface is among the first detectable events in atherogenesis. Cellular adhesion molecules, expressed by the vascular endothelium and by circulating leucocytes, mediate cell recruitment and their transendothelial migration. Platelet endothelial cellular adhesion molecule 1 (PECAM-1/CD31), involved in this migration, has been associated with the developmental course of atherosclerosis. A few studies have investigated an association between coronary heart disease and single nucleotide polymorphisms (SNPs) located in functionally important domains of the PECAM-1/CD31 gene. In particular, Ser563Asn and Gly670Arg SNPs have been described as susceptibility factors involved in acute myocardial infarction (AMI) in the Japanese male population. To confirm these observations, we studied 96 male patients (mean age 40 years; age range 20–46) affected by AMI and 118 healthy male controls (mean age 38 years, age range: 20–55), and analysed for the following PECAM-1/CD31 SNPs: Val125Leu, Asn563Ser and Gly670Arg. The frequency of the Gly670Arg polymorphism was significantly higher in patients with AMI (58.9% vs. 48.3%; P = 0.019), whereas the frequencies of the other two SNPs (Leu125Val and Ser563Asn) were not significantly different between patients and controls. By comparing the observed number of 670Arg/Arg genotypes in the patients with the expected number, calculated from the allele frequency in a healthy population, a significance of P = 0.02 (odds ratio, 2.04; 95% CI: 1.1–3.7) was obtained, supporting a recessive model of inheritance. Hence, the differences between patients and controls are significant, but relatively small. However, as AMI is a multifactorial disease, any single mutation will only provide a small or modest contribution to the risk, which also depends on environmental interaction. All in all, we believe that the results of the present study would add support to the role of pro/anti-inflammatory genotypes in determining susceptibility or resistance to immune-inflammatory diseases, including atherosclerosis.