European Journal of Human Genetics (2002) 10, 292–296 2002 Nature Publishing Group All rights reserved 1018-4813/02 $25.00

an increased frequency of Arg192 allele in centenarians

Bonafe`1,9, Francesca Marchegiani2,9, Maurizio Cardelli2, Fabiola Olivieri2, Cavallone2, Simona Giovagnetti2, Carlo Pieri2, Maurizio Marra2, Roberto Troiano3, Paola Gueresi4, Giovanni Passeri5, Maurizio Berardelli6,8, Paolisso7, Michelangela Barbieri7, Silvia Tesei2, Rosmarie Lisa2, De Benedictis8 and Claudio Franceschi*,1,2

1Department of Experimental Pathology, Bologna University, Bologna, Italy; 2Italian National Research Centers on Aging, Ancona, Italy; 3Department of Biomedical Sciences, University of Modena, Modena, Italy; 4Statistical Science, University of Bologna, Bologna, Italy; 5Institute of Internal Medicine and Medical Therapy, University of Parma, Parma, Italy; 6Department of Geriatrics and Internal Medicine, University of Magna Graecia, Catanzaro, Italy; 7Department of Geriatric Medicine and Metabolic Disease, II University of Naples, Naples, Italy; 8Department of Cell Biology, University of Calabria, Rende, Italy

lipo-peroxides. PON1 has recently attracted attention as a protective factor against oxidative modification of LDL and may therefore play an important role in the prevention of the atherosclerotic process. Two polymorphisms have been extensively studied: a Leucine (L allele) to Methionine (M allele) substitution at codon 55, and a Glutamine (A allele) to Arginine (B allele) substitution at codon 192. We have examined these two aminoacidic changes in 579 people aged 20 to 65 years old, and 308 centenarians. We found that the percentage of carriers of the B allele at codon 192 (B+ individuals) is higher in centenarians than in controls (0.539 vs 0.447), moreover we found that among the B+ individuals, the phenomenon was due to an increase of people carrying M alleles at codon 55 locus. In conclusion, we propose that genetic variability at PON1 locus affects survival at extreme advanced age. European Journal of Human Genetics (2002) 10, 292 – 296. doi:10.1038/sj.ejhg.5200806

Keywords: polymorphism; human longevity; apolipoproteins; aging

Introduction

atherogenesis and to the capability of proteins of modulating local inflammatory response.4

A great deal of data indicate that risk factors for the major causes of mortality in the elderly, (cardiovascular diseases, diabetes) are associated with alterations in anti-oxidant, inflammatory and lipidic profile.1–3 Particular importance has been attributed to the role of peroxidation of LDL in

Serum Paraoxonase 1 (PON1) has been claimed to play a central role in the scenario. The enzyme is a High Density Lipoprotein (HDL)-bound Arylesterase which hydrolises lipo- peroxides and it is therefore responsible for the protective effects of HDL on peroxidation of Low Density Lipoproteins (LDL).5 Indeed, oxydised LDL are capable of stimulating the production of foam cells, are cytotoxic towards arterial wall cells, and induce macrophagic cytokines, resulting in highly proinflammatory and proatherogenic.6 The inter-individual variability of PON1 serum activity has been thought to modulate the risk to develop atherogenesis. In fact, the

*Correspondence: C Franceschi, Direzione Scientifica I.N.R.C.A., Villa Gusso, Via S. Margherita,

Ancona, Italy. Tel: +

-

-

; Fax: +

-

-

; E-mail: b.molecolare@inrca.it

The first two authors contributed equally to this study Received

December

; revised

March

; accepted

of 5 min at 728C. The PCR products were digested with NlaIII (New England Biolabs) for 4 h at 378C, and the samples were electrophoresed in 2% agarose gels. Some genotypes at both loci were confirmed by direct sequencing of amplified DNA fragments with the automatic sequencer (ABI PRISM 310, Perkin Elmer Biosystem).

variability of the PON1 gene at codons 192 (Gln/Arg=A/B alleles) and 55 (Leu/Meth=L/M alleles) has been associated with enzymatic activity and concentration.7,8 Consistently, a large number of studies suggested an association between cardiovascular diseases and the Arg variant.9 Even Leu 192 55 has been associated with cardiovascular disease susceptibil- ity.9 Recently, the role of Arg allele on CHD (cardiovascular 192 heart disease) risk in the Italian population has been questioned10 and recent data indicate that PON1 genotype affects the vasculature responsiveness to triglycerids.11 Interestingly, when the impact of A/B and L/M alleles of PON1 on mortality of individuals aged over 85 years of age was analysed, no significant effect has been found, leading to hypothesise that PON1 variants have not a major effect on the risk of fatal cardiovascular disease at the population level.12

Statistical analysis

Allelic, genotypic and combined genotypes frequency dis- tributions were compared by Monte Carlo w2. Sex-specific age-related differences were assessed by Mantel-Haenszel test, implemented with SPSS package (SPSS, Chicago, IL, USA). HWE (Hardy-Weinberg Equilibrium) was checked by Monte Carlo Markov Chain.15 Estimation of maximum-likelihood multi-locus haplotype frequencies was calculated using an EM (Expectation Maximization) algorithm, implemented with Arlequin package.16 Standard Deviations were calcu- lated by bootstrap (1000 replications). Difference in haplo- type frequency distribution was assessed by Fisher exact test.

In this study we wanted to test the hypothesis that PON1 genotypes affect long term survival, i.e. whether allele, genotype and combined genotypes frequency distributions of centenarians are different from those found in young individuals.

Results

PON1 192 alleles and genotypes in young people and centenarians

Materials and methods