Experimental Gerontology 39 (2004) 1089–1094

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Association between serum paraoxonase (PON1) gene promoter T(-107)C polymorphism, PON1 activity and HDL levels in healthy Sicilian octogenarians

a a b a a Campo , Maria A. Sardo , Giuseppe Trimarchi , Michele Bonaiuto , Luisa Fontana , a a a a Maria Castaldo , Antonio Bonaiuto , Carlo Saitta , Alessandra Bitto , Bruno Manducaa , Stefania Riggioa , Antonino Saittaa,*

aDepartment of Internal Medicine, 82 Via Camiciotti, Messina 98123, University of Messina, Italy bInstitute of Statistical Science, 82 Via Camiciotti, Messina 98123, University of Messina, Italy

Received 14 November 2003; received in revised form 3 March 2004; accepted 5 March 2004

Abstract

Age is associated with an enhanced low density lipoprotein (LDL) oxidation and atherosclerosis, thus, subjects over 80 years without cardiovascular disease provide a model to investigate the protective factors against atherosclerosis. Serum paraoxonase (PON1), an high density lipoprotein (HDL)-bound enzyme, prevents LDL oxidation.

The aim of the present study was to evaluate the contribution of the PON1 promoter T(-107)C and coding region Gln192Arg (Q192R) and Leu55Met (L55M) polymorphisms to the resistance to develop cardiovascular events in Sicilian healthy octogenarians. Distribution of PON1 genotypes and activity, and biochemical parameters, were compared between 100 octogenarians and 200 adults. Individuals in the elderly group displayed significant higher levels of HDL-C ðP , 0:001Þ and PON1 activity ðP , 0:001Þ: The analysis of PON1 genotypes distribution showed an higher percentage of (-107)CC among octogenarians compared with controls. A significant difference among T(-107)C genotypes respect to PON1 activity and HDL-C levels occurred in both groups. The CC genotype was associated with higher PON1 activity and HDL levels compared to the TT genotypes.

In conclusion, our results provide a strong evidence that in healthy Sicilians ageing may be characterized by a low frequency of PON1 (-107)T ‘risk’ allele and by an high frequency of favourable genotypes such as (-107)CC, influencing PON1 activity and HDL-C levels. q 2004 Elsevier Inc. All rights reserved.

Keywords: Paraoxonase polymorphism; Octogenarians; PON 1; T(-107)C; Q192R; L55M

1. Introduction

in frequency with ageing (Hofman et al., 1991; Fried et al., 1998). Thus, the old subjects who achieve long life-spans in absence of severe atherosclerosis related disorders, such as coronary artery disease (CAD), stroke and peripheral artery disease, can provide a model to investigate the protective factors increasing their resistance to develop atherosclerotic disease (Rowe and Kahn, 1987).

The elderly persons have been suggested to have a greater risk for oxidative stress (Beckman and Ames, 1998) and low density lipoprotein (LDL) oxidation (Jira et al., 1996), which may contribute to the increased incidence of atherosclerotic disease in this population (Steinberg et al., 1989). A decline in protective mechanisms against oxidative stress has also been found during ageing (Azhar et al., 1995; Napoli et al., 1997; Lykkesfeldt et al., 1998). Moreover, conditions such as hypertension, smoking habit, diabetes and hypercholesterolemia, which may enhance oxidative

Human serum paraoxonase (PON1), a high density lipoprotein (HDL) associated ester hydrolase enzyme has been shown to protect LDL from oxidation by the hydrolysis of biologically active lipoperoxides (Mackness et al., 1991). Animal models, including PON1-knockout mice, demon- strated that PON1 deficiency was related to an increased susceptibility of LDL to oxidation and atherosclerosis

* Corresponding author. Tel.: þ

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- E-mail address: asaitta@unime.it (A. Saitta).

S. Campo et al. / Experimental Gerontology 39 (2004) 1089–1094

development (Shih et al., 1996). In human, it has been suggested that PON1 is significantly associated with CAD risk (Mackness et al., 1991; Ayub et al., 1999) and that its activity is under genetic regulation an vary widely among individuals and populations (Sanghera et al., 1998). PON1 activity variation has been related mainly to the expression of two polymorphisms located in the coding region of PON1 gene, Glutamine 192 Arginine (Q192R) and Leucine 55 Metionine (L55M; Ruitz et al., 1995; Garin et al., 1997). While the L55M polymorphism affects serum PON1 levels (Garin et al., 1997), 192 Q and R isoforms show low and high activity, respectively, towards synthetic substrate paraoxon (Ruitz et al., 1995). The role of these polymorph- isms in predicting atherosclerosis remains controversial, actually several studies revealed a significant association between PON1 coding region polymorphisms and CAD risk (Sanghera et al., 1997,1998; Ruitz et al., 1995; Garin et al., 1997; Serrato and Marian, 1995; Salonen et al., 1999) while others reported a lack of association (Herrmann et al., 1996; Ombres et al., 1998; Gardemann et al., 2000; Arca et al., 2002).

Inclusion criteria for study population were normal ECG pattern and no history or clinical signs of arterial disease including CAD, stroke or peripheral arterial disease (PAD). Subjects with cognitive (Mini-Mental State Examination) and functional (Barthel Index and Instrumental Activities of Daily Living) impairment, thyroid, hepatic or kidney disease, infectious or autoimmune disease were excluded from the study.

Table 1 shows the characteristics of the study population. In all the subjects blood pressure, height, and weight were measured by routine methods and venous blood for clinical chemistry and DNA analysis was collected after overnight fasting.