. Corrected and improved text:

Title: APOE and longevity among Han Chinese population

Authors: Zhang Jian-Gang, Ma Yong-Xing, Wang Chuan-Fu, Lu Pei-Fang, Zhen Song-Bai, Gu Nui-Fan, Feng Guo-Yin

Affiliations:
a. Section of Human Genome Project, Shanghai Research Center of Life Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, People's Republic of China
b. Department of Aging and Anti-aging, Shanghai Institute of Gerontology and Geriatric, Huadong Hospital, 221 West Yan An Road, Shanghai 200040, People's Republic of China
c. Shanghai Mental Center, 600 South Wan Ping Road, Shanghai 200030, People's Republic of China
d. Shanghai Brain Research Institute, Chinese Academy of Sciences, 320 Yue Yang Road

Received: 25 February 1998; revised: 15 May 1998; accepted: 21 May

Abstract:
The apolipoprotein E gene (APOE), located on chromosome 19, has three common APOE alleles encoding APOE*2, APOE*3 and APOE*4. It has been considered to be closely associated with human longevity among Western populations. However, the allele frequency varies among racial and ethnic groups. We studied the relationship between APOE and longevity among 1562 Han Chinese (246 females and 1316 males) whose ages ranged from 20-108 years old in the Shanghai metropolitan area and Lian Yungang province. APOE was amplified by one-stage PCR using the forward primer: 5'-GGC ACG GCT GTC CAA GGA GCT-3' and reverse primer: 5'-GAT GGC GCT GAG GCC GCG CT-3'. The PCR product was digested directly with 5 U of CfoI and separated by a 20% polyacrylamide (acrylamide:bisacrylamide 29:1) non-denaturing gel. The allele frequency of APOE*4 in the very old age group (85 years) was significantly different from that in the youth (20-39 years), middle (40-59 years) and old (60-84 years) age groups (2.5% vs 8.4%, 7.9% or 7.6%; p < 0.05), respectively.

Keywords: Apolipoprotein E; Longevity; Han Chinese; PCR; RFLP

Introduction:
Many factors relating to longevity have been studied in the past, and it has been argued that genes play a key role in the aging process. At present, two main developments in support of this hypothesis (Jazwinski, 1996) can be found. The first one was from efforts to test evolutionary theories of aging, and the second one arose from studies of genes modulating lifespan. Smith and Walford (1977) and Walford and Bergmann (1979) found evidence that the main histocompatibility genes H-2 in mice had played an important role in lifespan by inducing an appropriate immune response or by influencing DNA repair capacity. Although there is evidence supporting the contention that a genetic component contributes to the determination of human longevity, the only association reported so far is the HLA locus, which was reported by three independent investigations (Proust et al., 1982; Takata et al., 1987; Yong-Xing et al., 1997). In order to search for genetic influences on human longevity in Han Chinese, we studied a candidate gene, Apolipoprotein E (APOE), which had been well characterized in the Western population.

Subjects:
Blood samples were collected from 1562 healthy people (246 females and 1316 males, Table 1) with ages ranging from 20-108 years old. A total of 1506 unrelated samples were gathered from the Shanghai area and 56 people were selected from Lian Yungang city, Jiangsu province, which is 600 km away from Shanghai. The selected healthy subjects had to meet the following criteria: good physical and mental health confirmed by clinical, radiological, biological examinations and a brief cognitive test (Ming-Yuan et al., 1990). Regarding their ages, all subjects were divided into the following subgroups: youth (20-39 years old), middle (40-59 years old), old (60-84 years old) and very old (85 years old) age groups, respectively. The acid citrate dextrose (ACD) was used as anticoagulant (Sambrook et al., 1989).

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