Association between senescent surface markers and pre-frailty in older subjects

Purpose Frailty is highly prevalent in old age and confers high risk for falls, disability, hospitalization, and mortality. Although the exact cause of frailty is still to be elucidated, immuno-senescence has been implicated in the pathophysiology of the syndrome. Therefore, we investigated the relationship between senescent surface markers and the risk of frailty in community-dwelling older subjects. Methodology One hundred and seventy-five apparently healthy older individuals (82 females and 93 males, 79,9 to 98,5 years) who presented no active pathology were enrolled in this study. Pre-frailty was defined by using the Fried et al. criteria. The surface markers of senescence were determined by using flow cytometry. Results The overall prevalence of pre-frailty was 94 (53,7%). Pre-frail subjects were significantly older than robust individuals (p<0,001) and the prevalence of pre-frailty was greater in men than women (p=0,003). Pre-frailty was associated with increased CD8-/CD8+ ratio (p=0,026, unadjusted and p=0,034, adjusted for age and sex). There were no significant differences in the expression of senescent surface markers in pre-frail compared to robust when men and women were treated separately. Though the percentage of CD8+CD28-CD57+ correlated positively with age (r=0,214, p=0,004), age did not affect the relationship between senescent marker expression and the risk of pre-frailty. Conclusion Our results portray that pre-frailty depends on sex and age. Also, in accordance with another on the oldest old in Belgium - the BELFRAIL Study - high CD8-/CD8+ ratios 5/39 were associated with pre-frailty. Further investigation is necessary to shed more light into this observation.