Development of a serum profile for healthy aging

Abstract

Increasing numbers of Americans are reaching 85 years of age or older, yet there are no reliable biomarkers to predict who will live this long. The goal of this pilot study therefore was: (1) to identify a potential serum pattern that could identify proteins involved in longevity and (2) to determine if this pattern was a marker of longevity in an independent sample of individuals. Serum samples were analyzed in three cohorts of individuals (n = 12 in each) aged 20-34, 60-74, and ≥ 90 years who participated in The Louisiana Healthy Aging Study. The 12 most abundant proteins were removed and the remaining proteins separated by two-dimensional gel electrophoresis. Gels were matched and the intensity of each spot quantified. Multivariate discriminant analysis was used to identify a serum pattern that could separate these three age cohorts. Seven protein spots were found that correctly distinguished the subjects into the three groups. However, these spots were not as successful in discriminating the ages in a second set of 15 individuals as only eight of these subjects were placed into their correct group. These preliminary results show that the proteomics approach can be used to identify potential proteins or markers that may be involved in the aging process and/or be important determinants of longevity.

Fig. 1

Representative 2-D gel electrophoresis of serum. The seven spots circled are the spots identified to discriminate among the three age groups

Fig. 2

Graphical representation of the first two components from the principal component analysis of the serum spots (a and b) and the average intensity of the seven spots selected by discriminant analysis (c). Individual subjects from each age group (filled circle young, filled triangle old, unfilled circle elderly) are shown in the training group (a) and test group (b). For c, the average ± SEM are shown for each group for each spot