Indicator Of Biological Aging Research Articles

Telomeres and Human Somatic Fitness

Mean leukocyte telomere length may be an indicator of biological age, and as such it appears to provide information over and above chronological age of the risk for developing diseases of aging in humans. Here I propose that the mean leukocyte telomere length is an index of "somatic fitness," a concept that breaks down the artificial boundary between aging and diseases of aging. I also propose that, in exceptionally old humans, ultrashort leukocyte telomeres might be a determinant of life span.

Frailty Index as a Measure of Biological Age in a Chinese Population

The concept of a frailty index, developed in Canadian elderly populations as an indicator of biological age as opposed to chronological age, was tested in an elderly Chinese population to determine whether it is applicable in a different ethnic and cultural setting. A data set including 62 physical, psychological, and socioeconomic variables from a cohort of 2,032 persons 70 years and older (999 men, 1,033 women) was used. The distribution of the index was evaluated using the Cramer-von Mises goodness-of-fit test, and multiple linear regression was used to assess its relationship with age and sex. A biological age for each participant was calculated based on an inverse regression of age on mean frailty index and sex. The Cox proportional hazards regression model was used to assess the ability of biological age to predict death. The distribution of the frailty index most closely resembled a Weibull distribution. The frailty index increased with age until the mid-80s, when it leveled off, and was higher in women than men for each age group. The distribution of biological age is wider than that for chronological age, and it strongly predicted death. Women had an estimated 20% lesser chance of dying at a given time than did men of the same chronological age and degree of frailty. The study confirms the robustness of the concept and method of calculating the frailty index developed in elderly Canadian populations. It also suggests that the sex difference in life expectancy may have an underlying genetic basis independent of frailty.

Effect of repeated stress on a number of plasma amino acids and related compounds in young and old rats

A number of amino compounds were studied in the plasma of young and old rats exposed to an immobilization stress on 3 different days. Baseline values were similar for all compounds between age groups except for slightly higher phenylalanine levels in old animals. Most differences were seen in the stress responses. Stress response intensities for alanine, aspartic acid, methionine, phenylalanine, and tyrosine were generally higher in old rats and recovery times from stress were usually longer. Although the stress responses decreased in young rats for some compounds over the three exposures, old rats showed no or less adaptation during this time. All the other amino acids showed no marked age effects. This study shows that certain plasma amino acids can serve as selective indicators of biological age and that their stress responses might be better markers of the aging process than their resting levels.

Effect of Repeated Stress on a Number of Plasma Amino Acids and Related Compounds in Young and Old Rats

A number of amino compounds were studied in the plasma of young and old rats exposed to an immobilization stress on 3 different days. Baseline values were similar for all compounds between age groups except for slightly higher phenylalanine levels in old animals. Most differences were seen in the stress responses. Stress response intensities for alanine, aspartic acid, methionine, phenylalanine, and tyrosine were generally higher in old rats and recovery times from stress were usually longer. Although the stress responses decreased in young rats for some compounds over the three exposures, old rats showed no or less adaptation during this time. All the other amino acids showed no marked age effects. This study shows that certain plasma amino acids can serve as selective indicators of biological age and that their stress responses might be better markers of the aging process than their resting levels.

Distribution of α-tocopherol in early foliage samples in several forage crops

Concentrations of α-tocopherol in foliage samples of the forages annual rye, winter rye, red fescue, Kentucky blue-grass and white clover were determined. Concentrations of α-tocopherol increased with age in all four of the grasses tested during the six-week experimental period to values of 70.9, 80.9, 94.0 and 146.7 μg g −1 dry wt in annual rye, winter rye, red fescue and Kentucky blue-grass, respectively. White clover, the only legume forage tested, did not increase α-tocopherol concentrations with age, remaining at about 20 μg g −1 dry wt for each time sample. These results support the hypothesis that concentrations of α-tocopherol may act as indicators of biological age, although exceptions to this concept are likely to exist.

Age dependent α-tocopherol concentrations in leaves of soybean and pinto beans

The concentrations of α-tocopherol in foliage samples of soybeans ( Glycine max) and pinto beans ( Phaseolus vulgaris) were investigated. In both species, the α-tocopherol concentrations increased with age. Four-week-old soybeans had α-tocopherol concentrations of 135.1, 64.2 and 48.9 μg g −1 dry wt in unifoliates, first trifoliates and second trifoliates, respectively, while four-week-old pinto beans had α-tocopherol concentrations of 288.7, 123.3 and 40.6 μg g −1 dry wt in unifoliates, first trifoliates and second trifoliates. These results strengthen the hypothesis that increasing levels of α-tocopherol may act as an indicator of biological age in various plant species.

Divergence of biological and chronological aging: Evidence from rodent studies

Literature on aging populations of rodents supports the intuitive view that significant functional variation exists among like-aged, elderly individuals: chronological age as a solitary measure is a poor indicator of biological age. In this report, we review a variety of studies which classify aged rodents based on genetic and/or behavioral similarities, in addition to chronological age, and have provided valuable neurobiological and physiological information on age-related changes which accompany functional impairments, or the lack of them. Beyond their descriptive value for gerontological research, these findings suggest ways in which biological aging can be manipulated to promote good function in aged individuals.