A Clinical Frailty Index in Aging Mice: Comparisons With Frailty Index Data in Humans

Abstract

We previously quantified frailty in aged mice with frailty index (FI) that used specialized equipment to measure health parameters. Here we developed a simplified, noninvasive method to quantify frailty through clinical assessment of C57BL/6J mice (5–28 months) and compared the relationship between FI scores and age in mice and humans. FIs calculated with the original performance-based eight-item FI increased from 0.06±0.01 at 5 months to 0.36±0.06 at 19 months and 0.38±0.04 at 28 months (n = 14). By contrast, the increase was graded with a 31-item clinical FI (0.02±0.005 at 5 months; 0.12±0.008 at 19 months; 0.33±0.02 at 28 months; n = 14). FI scores calculated from 70 self-report items from the first wave of the Survey of Health, Ageing and Retirement in Europe were plotted as function of age (n = 30,025 people). The exponential relationship between FI scores and age (normalized to 90% mortality) was similar in mice and humans for the clinical FI but not the eight-item FI. This noninvasive FI based on clinical measures can be used in longitudinal studies to quantify frailty in mice. Unlike the performance-based eight-item mouse FI, the clinical FI exhibits key features of the FI established for use in humans.

Pathophysiology of heart failure and frailty: a common inflammatory origin?

“…This study represents a potential murine model of frailty; however, it is confounded as IL‐10‐deficient mice exhibit signs of inflammatory bowel disease (Davidson et al ., 2000), which could explain the features described in the study. Recently, a frailty index in aging wild‐type C57BL/6 strain mice has been developed by measuring 31 health‐related variables including mobility, hemodynamic, metabolic, and body composition parameters both invasively (Parks et al ., 2012) and more recently with noninvasive approaches (Whitehead et al ., 2014). Furthermore, others have robustly characterized physical function measures in mice to standardize measures which could provide index values for physical function to aide in establishing murine models of frailty (Justice et al ., 2014).…”

Animal models of frailty: current applications in clinical research

“…Whitehead et al29 continued this work on the development of a mouse FI. We developed a mouse clinical FI which utilizes 31 simply assessed, and noninvasive, clinical measures to quantify frailty in C57BL/6J mice.…”

The Biology of Aging

“…A noteworthy advance in the area of experimental healthspan assessment is the recent description of a non-invasive frailty index for quantifying healthspan in mice 97 . Indices of frailty have been commonly used in geriatric medicine, but are rarely applied in studies of aged rodents.…”